Composite material, light-emitting element, light-emitting device, electronic device, lighting device, and organic compound

The present invention relates to a composite material in which an organic compound and an inorganic compound are combined, a light emitting element, a light emitting device, an electronic device, and a lighting device. It also relates to an organic compound that can be used in the composite material.

In recent years, research and development of light emitting devices using organic electroluminescence (EL) have been actively carried out. The basic configuration of these light emitting elements is that a layer containing a luminescent organic compound is sandwiched between a pair of electrodes. By applying a voltage to this device, it is possible to obtain light emission from a luminescent organic compound.

Since such a light emitting element is a self-luminous type, it has advantages such as higher visibility of pixels and no need for a backlight as compared with a liquid crystal display, and is considered to be suitable as a flat panel display element. Further, it is a great advantage that such a light emitting element can be manufactured thin and lightweight. Another feature is that the response speed is extremely fast.

Further, since these light emitting elements can be formed in a film shape, a large area element can be easily formed. This is a feature that is difficult to obtain with a point light source represented by an incandescent lamp or an LED, or a line light source represented by a fluorescent lamp, and therefore has high utility value as a surface light source that can be applied to lighting or the like.

As described above, light emitting elements using organic EL are expected to be applied to light emitting devices and lighting. On the other hand, there are many problems with light emitting devices using organic EL. One of the issues is reduction of power consumption. In order to reduce power consumption, it is important to lower the drive voltage of the light emitting element. Since the emission intensity of a light emitting element using an organic EL is determined by the amount of current flowing through it, it is necessary to pass a large amount of current at a low voltage in order to lower the drive voltage.

So far, as a method for lowering the drive voltage, an attempt has been made to provide a buffer layer between an electrode and a layer containing a luminescent organic compound. For example, it is known that the drive voltage can be lowered by providing a buffer layer made of polyaniline (PANI) doped with camphorsulfonic acid between an indium tin oxide (ITO) and a light emitting layer (ITO). For example, see Non-Patent Document 1). It is explained that this is because PANI has excellent carrier injection into the light emitting layer. In Non-Patent Document 1, PANI, which is a buffer layer, is also regarded as a part of the electrode.

However, as described in Non-Patent Document 1, PANI has a problem that the transmittance deteriorates as the film thickness increases. Specifically, it is reported that the transmittance is less than 70% at a film thickness of about 250 nm. That is, since there is a problem in the transparency of the material itself used for the buffer layer, the light generated inside the device cannot be efficiently extracted.

Further, according to Patent Document 1, an attempt is made to increase the brightness per certain current density, that is, the current efficiency by connecting light emitting elements (described as a light emitting unit in Patent Document 1) in series. There is. In Patent Document 1, a layer in which an organic compound and a metal oxide (specifically, vanadium oxide and renium oxide) are mixed is applied to a connecting portion when connecting light emitting elements in series, and this layer is used. It is said that holes and electrons can be injected into the light emitting unit.

However, as can be seen from the examples, the mixed layer of the organic compound and the metal oxide disclosed in Patent Document 1 has a large absorption peak not only in the infrared region but also in the visible light region (around 500 nm). It is seen, and there is still a problem with transparency. This is the effect of the absorption band generated by the charge transfer interaction. Therefore, the light generated inside the element cannot be efficiently extracted, and the luminous efficiency of the element is lowered.

<p num="0010"><patcit num="1"><text>Japanese Unexamined Patent Publication No. 2003-272860</text></patcit></p>

<p num="0011"><nplcit num="1"><text>Y.Yang, and one other person, Apu ride Physics Letters, Vol.64 (10), 1245-1247 ( 1994)</text></nplcit></p>

<p num="0012">Therefore, in one aspect of the present invention, it is an object of the present invention to provide a composite material in which an organic compound and an inorganic compound are composited, which has high carrier transportability. Another issue is to provide a composite material having high carrier injection properties into organic compounds. Another object of the present invention is to provide a composite material in which light absorption due to charge transfer interaction is unlikely to occur. Another issue is to provide a composite material having high translucency to visible light.</p><p num="0013">Another object of one aspect of the present invention is to provide a light emitting element having high luminous efficiency by applying the composite material to the light emitting element. Another issue is to provide a light emitting element having a low drive voltage. Another issue is to provide a light emitting element having a long life. Another object of the present invention is to provide a light emitting device using the light emitting element, an electronic device or a lighting device using the light emitting device.</p><p num="0014">The invention disclosed below aims to solve at least one of the above problems.</p>

<p num="0015">One aspect of the present invention includes an organic compound and an inorganic compound exhibiting electron acceptability for the organic compound, and the organic compound has only a benzene ring, and the number of benzene rings contained in the organic compound. Is a composite material of 4 or more and 25 or less. Unless otherwise specified, the ring (benzene ring) contained in the organic compound contained in the composite material of one aspect of the present invention may be either substituted or unsubstituted.</p><p num="0016">Alternatively, one aspect of the present invention includes an organic compound having a molecular weight of 350 or more and 2000 or less and an inorganic compound exhibiting electron acceptability for the organic compound, and the ring of the organic compound is only a benzene ring. It is a composite material.</p><p num="0017">Alternatively, one embodiment of the present invention contains an organic compound and a transition metal oxide, and the organic compound has only a benzene ring, and the number of benzene rings contained in the organic compound is 4 or more and 25 or less. It is a composite material.</p><p num="0018">Alternatively, one aspect of the present invention is a composite material containing an organic compound having a molecular weight of 350 or more and 2000 or less and a transition metal oxide, and the ring of the organic compound is only a benzene ring.</p><p num="0019">The composite material has high carrier transportability. In addition, it has high carrier injection properties into organic compounds. In addition, light absorption due to charge transfer interaction is unlikely to occur. In addition, it has high translucency with respect to visible light (hereinafter, simply referred to as translucency).</p><p num="0020">The absorption peak of the organic compound contained in the composite material of one aspect of the present invention occurs on the shorter wavelength side than the visible light region (380 nm to 760 nm).</p><p num="0021">The composite material not only suppresses the generation of light absorption due to the charge transfer interaction, but also can control the absorption peak of the organic compound itself to occur on the shorter wavelength side than the visible light region (380 nm to 760 nm). A composite material having high translucency can be obtained.</p><p num="0022">When the molecular weight of the organic compound is 350 or more, the film quality of the composite material is stabilized, which is preferable. It is particularly preferable that the molecular weight is 450 or more. The upper limit of the molecular weight is not particularly limited, but when the composite material is formed by heat-deposited, it is preferably 2000 or less in consideration of the vapor deposition property.</p><p num="0023">Further, the organic compound may have an alkyl group having 1 to 6 carbon atoms as a substituent. Moreover, the organic compound may contain silicon. For example, the organic compound may have a silicon-crosslinked benzene ring. When the benzene ring is bonded to another benzene ring via silicon, the conjugated system does not easily extend between these benzene rings, which is effective from the viewpoint of translucency.</p><p num="0024">Further, the organic compound may have a trialkylsilyl group as a substituent. When the organic compound has a trialkylsilyl group which is a bulky (bulky) substituent, the amorphous property of the single film of the organic compound can be enhanced. Therefore, in one aspect of the present invention, not only has a high singlet excitation energy level (S1 level) and a triplet excitation energy level (T1 level), and also has high translucency, but also has a large molecular weight. , An organic compound having high heat resistance and high amorphousness of the film can be used.</p><p num="0025">Further, from the viewpoint of carrier transportability, it is preferable that two or more benzene rings are connected in a single bond (for example, it is preferable to have a biphenyl group or the like). In addition, from the viewpoint of thermophysical characteristics, when many benzene rings are connected by a single bond in order to increase the molecular weight, it is preferable to connect them at the ortho or meta position or to crosslink with silicon so that the conjugated system does not extend too much. ..</p><p num="0026">The maximum occupied orbital level (HOMO level) of the organic compound used in the above composite material is not particularly limited, but the organic compound used in one aspect of the present invention has a relatively deep HOMO level (specifically,-. It has 5.7eV or less). Therefore, it is possible to suppress the occurrence of light absorption based on the charge transfer interaction. Therefore, the HOMO level of the organic compound used in the composite material is preferably -5.7 eV or less as measured by photoelectron spectroscopy.</p><p num="0027">The transition metal oxide contained in the composite material includes titanium oxide, vanadium oxide, molybdenum oxide, tungsten oxide, renium oxide, ruthenium oxide, chromium oxide, zirconium oxide, and hafnium oxide. , Tantalu oxide, one or more selected from silver oxide is preferable.</p><p num="0028">Further, one aspect of the present invention is a light emitting device having a layer containing a light emitting substance (hereinafter, also referred to as an EL layer) between a pair of electrodes, and the layer containing the light emitting substance has a layer containing the above composite material. ..</p><p num="0029">In the light emitting device, the layer containing the composite material is preferably in contact with the electrode functioning as the anode among the pair of electrodes. Further, the layer containing the composite material is preferably in contact with the electrode that functions as a cathode among the pair of electrodes.</p><p num="0030">Further, the light emitting device may have two layers containing a composite material, and one of the layers containing the composite material is in contact with an electrode that functions as an anode among a pair of electrodes and the other. The layer is preferably in contact with an electrode that functions as a cathode.</p><p num="0031">Here, as described above, the organic compound used in one embodiment of the present invention has a relatively deep HOMO level (specifically, -5.7 eV or less). Therefore, the organic compound (organic compound used for the hole transport layer, the light emitting layer, etc.) used for the layer in contact with the cathode side of the layer containing the composite material has a relatively deep HOMO level (for example, -6.0 eV). Even in this case, hole injection from the composite material into the organic compound can be performed satisfactorily. Of course, even when the organic compound has a shallow HOMO level (for example, -5.0 eV), hole injection from the composite material into the organic compound can be performed satisfactorily. Therefore, the HOMO level of the organic compound contained in the layer in contact with the cathode side of the layer containing the composite material (hereinafter referred to as the first layer) is preferably -6.0 eV or more and -5.0 eV or less.</p><p num="0032">Further, the difference in HOMO level between the composite material and the organic compound is preferably small, and the difference is preferably within 0.2 eV. Further, as described above, from the viewpoint of reducing the difference between the HOMO level of the organic compound used in the first layer and the HOMO level of the organic compound used in the composite material, the organic compound used in the first layer It is preferable to use an organic compound having only a benzene ring (the number of the benzene rings is 4 or more and 25 or less, or the molecular weight of the organic compound is 350 or more and 2000 or less). For example, the same organic compound as the organic compound used in the above composite material may be used. In particular, when a plurality of benzene rings contained in the organic compound are bonded at the ortho-position or the meta-position, the film has high amorphousness and can be suitably used for the first layer. Moreover, since it has a high T1 level, it can be particularly suitably used for the first layer of a phosphorescent light emitting device.</p><p num="0033">Further, from the same viewpoint, the light emitting layer in contact with the first layer is also an organic compound having only a benzene ring (the number of the benzene rings is 4 or more and 25 or less, or the molecular weight of the organic compound is 350 or more and 2000. It is preferable to include (particularly, as a host material). For example, the same organic compound as the organic compound used in the above composite material may be used. In particular, when a plurality of benzene rings contained in the organic compound are bonded at the ortho-position or the meta-position, the film has high amorphousness and can be suitably used for (the host material of) the light emitting layer. Further, since it has a high T1 level, it can be particularly suitably used for (a host material) of a light emitting layer of a phosphorescent light emitting device.</p><p num="0034">That is, one aspect of the present invention has a layer containing a luminescent substance between a pair of electrodes, and the layer containing the luminescent substance is a layer containing the composite material, a first layer, and a luminescent layer from the anode side. The layer containing the composite material, the first layer, and the light emitting layer are organic compounds having only a benzene ring (the number of the benzene rings is 4 or more and 25 or less, or the organic). It is a light emitting element containing (the molecular weight of the compound is 350 or more and 2000 or less).</p><p num="0035">In particular, it is preferable that the organic compound contained in the layer containing the composite material, the first layer, and the light emitting layer is the same compound because the hole injection property between these layers is good. In addition, the synthesis cost can be suppressed, which is preferable.</p><p num="0036">Further, in the light emitting layer, the first organic compound is dispersed in the second organic compound, the ring of the second organic compound is only the benzene ring, and the benzene of the second organic compound. The number of rings is preferably 4 or more and 25 or less.</p><p num="0037">Further, one aspect of the present invention has a first EL layer to an nth EL layer (n is a natural number of 2 or more) between a pair of electrodes, and a kth EL layer (k is 1 or more and less than n). It is a light emitting device having a layer containing the above-mentioned composite material between the (natural number) and the (k + 1) th EL layer. That is, the composite material can be used for an intermediate layer (also referred to as a charge generation layer) in an organic EL light emitting device (tandem type organic EL light emitting device) having a structure in which a plurality of light emitting units are laminated. At this time, an organic compound having only a benzene ring in contact with the cathode side of the layer containing the composite material (the number of the benzene rings is 4 or more and 25 or less, or the molecular weight of the organic compound is 350 or more and 2000 It is preferable to provide a layer containing (the following).</p><p num="0038">Further, one aspect of the present invention is a light emitting device having the above light emitting element. Further, it is an electronic device having the light emitting device in the display unit. Further, it is a lighting device having the light emitting device in the light emitting unit.</p><p num="0039">Further, the organic compound represented by the following structural formula (112), which can be used for the composite material of one aspect of the present invention, is also a novel substance and is therefore included in the present invention. Therefore, one aspect of the present invention is an organic compound represented by the structural formula (112).</p><p num="0040"><chemistry num="1"><img id="000002" he="71" wi="158" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></chemistry></p>

<p num="0041">According to one aspect of the present invention, it is possible to provide a composite material in which an organic compound and an inorganic compound are composited, and which has high carrier transportability. Further, it is possible to provide a composite material having high carrier injection property into an organic compound. Further, it is possible to provide a composite material in which light absorption due to charge transfer interaction is unlikely to occur. Further, it is possible to provide a composite material having high translucency with respect to visible light.</p><p num="0042">Further, according to one aspect of the present invention, by applying the composite material to a light emitting element, it is possible to provide a light emitting element having high luminous efficiency. Further, it is possible to provide a light emitting element having a low drive voltage. Further, it is possible to provide a light emitting element having a long life. Further, it is possible to provide a light emitting device using the light emitting element, an electronic device using the light emitting device, and a lighting device.</p>

<figref num="1">The figure which shows the light emitting element of one aspect of this invention.</figref><figref num="2">The figure which shows the light emitting element of one aspect of this invention.</figref><figref num="3">The figure which shows the light emitting device of one aspect of this invention.</figref><figref num="4">The figure which shows the light emitting device of one aspect of this invention.</figref><figref num="5">The figure which shows the light emitting device of one aspect of this invention.</figref><figref num="6">The figure which shows the electronic device of one aspect of this invention.</figref><figref num="7">The figure which shows the lighting apparatus of one aspect of this invention.</figref><figref num="8">The figure which shows the absorption spectrum and the emission spectrum of the toluene solution of mBP3P.</figref><figref num="9">The figure which shows the absorbance of mBP3P of Example 1 and the composite material.</figref><figref num="10">The figure which shows 6P of Example 1 and the absorbance of the composite material.</figref><figref num="11">The figure which shows the absorbance of SiPSi of Example 1 and the composite material.</figref><figref num="12">The figure which shows the voltage-luminance characteristic of the light emitting element of Example 2.</figref><figref num="13">The figure which shows the luminance-current efficiency characteristic of the light emitting element of Example 2.</figref><figref num="14">The figure which shows the result of the reliability test of the light emitting element of Example 2.</figref><figref num="15">The figure which shows the voltage-luminance characteristic of the light emitting element of Example 3.</figref><figref num="16">The figure which shows the luminance-current efficiency characteristic of the light emitting element of Example 3. FIG.</figref><figref num="17">The figure which shows the result of the reliability test of the light emitting element of Example 3. FIG.</figref><figref num="18">The figure which shows the light emitting element of an Example.</figref><figref num="19">The figure which shows the voltage-luminance characteristic of the light emitting element of Example 4.</figref><figref num="20">The figure which shows the luminance-current efficiency characteristic of the light emitting element of Example 4.</figref><figref num="21">The figure which shows the absorption spectrum and the emission spectrum of the toluene solution of mTP3P.</figref><figref num="22">The figure which shows the absorption spectrum and the emission spectrum of the thin film of mTP3P.</figref><figref num="23">mBP22PSi¹The figure which shows the 1 H NMR chart.</figref><figref num="24">The figure which shows the absorption spectrum and the emission spectrum of the toluene solution of mBP22PSi.</figref><figref num="25">The figure which shows the absorption spectrum and the emission spectrum of the thin film of mBP22PSi.</figref><figref num="26">The figure which shows the luminance-current efficiency characteristic of the light emitting element of Example 7.</figref><figref num="27">The figure which shows the luminance-chromaticity coordinate characteristic of the light emitting element of Example 7.</figref><figref num="28">The figure which shows the luminance-external quantum efficiency characteristic of the light emitting element of Example 7.</figref><figref num="29">The figure which shows the emission spectrum of the light emitting element of Example 7.</figref><figref num="30">The figure which shows the result of the reliability test of the light emitting element of Example 7.</figref><figref num="31">The figure which shows the luminance-current efficiency characteristic of the light emitting element of Example 8.</figref><figref num="32">The figure which shows the luminance-chromaticity coordinate characteristic of the light emitting element of Example 8.</figref><figref num="33">The figure which shows the luminance-external quantum efficiency characteristic of the light emitting element of Example 8.</figref><figref num="34">The figure which shows the emission spectrum of the light emitting element of Example 8.</figref><figref num="35">The figure which shows the result of the reliability test of the light emitting element of Example 8.</figref><figref num="36">The figure which shows the luminance-current efficiency characteristic of the light emitting element of Example 9.</figref><figref num="37">The figure which shows the luminance-chromaticity coordinate characteristic of the light emitting element of Example 9.</figref><figref num="38">The figure which shows the luminance-external quantum efficiency characteristic of the light emitting element of Example 9.</figref><figref num="39">The figure which shows the emission spectrum of the light emitting element of Example 9.</figref><figref num="40">The figure which shows the result of the reliability test of the light emitting element of Example 9.</figref>

The embodiment will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it is easily understood by those skilled in the art that the form and details of the present invention can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention is not construed as being limited to the description of the embodiments shown below. In the configuration of the invention described below, the same reference numerals are commonly used between different drawings for the same parts or parts having similar functions, and the repeated description thereof will be omitted.

First, the outline of the difference between the technique behind the present invention and the present invention will be described. As shown in Patent Document 1, a composite material in which an aromatic amine and an electron-accepting inorganic compound are mixed is converted into an aromatic amine by depriving the aromatic amine of electrons. Holes are interpreted as the generation of electrons in inorganic compounds. In other words, such composites are interpreted as a charge transfer complex of aromatic amines and electron-accepting inorganic compounds. Then, using such a phenomenon, some composite materials having excellent carrier transportability and carrier injection property have been reported so far.

However, in such cases, it is generally known that an absorption band based on charge transfer interaction is generated. It is said that this absorption band occurs in the deep red to near-infrared region, but in reality, in many cases, an absorption band also occurs in the visible light region. For example, a composite material in which 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (abbreviation: NPB or α-NPD) and vanadium oxide, or NPB and molybdenum oxide are mixed is around 1300 nm. In addition to the absorption band of, an absorption band is also generated near 500 nm. This is a great disadvantage for optical devices such as light emitting elements.

The present inventors have an organic compound having only a benzene ring (the number of the benzene ring is 4 or more and 25 or less, or the molecular weight of the organic compound is 350 or more and 2000 or less) and a transition metal. By combining an oxide or an inorganic compound that exhibits electron acceptability with the organic compound, excellent carrier transport property is achieved even though light absorption based on charge transfer interaction cannot be confirmed (almost never occurs). And carrier injectability was found. Conventionally, holes and electrons generated by charge transfer interactions have been considered to be elements of carrier transportability and carrier injection properties, so that light absorption due to charge transfer interactions is not clearly observed. The present invention, which can exhibit excellent carrier transportability and carrier injection property, contradicts the general theory and can be said to be an unpredictable and surprising function.

As described above, the organic compound used in one embodiment of the present invention has only a benzene ring. Benzene has a large energy gap between its own HOMO level and LUMO level. In addition, the S1 level and the T1 level are high. Therefore, by using only the benzene ring as the ring of the organic compound, the organic compound itself can be designed to be a compound having no absorption peak in the visible light region (almost no absorption in the visible light region). Therefore, there is a great merit from the viewpoint of improving the translucency.

In addition, benzene has a very low HOMO level. Therefore, the simple substance of the organic compound used in one aspect of the present invention is considered to be excellent in hole injection into other organic compounds, but is a conductive material represented by Al or ITO (work function is 3). It is considered difficult to receive holes from ~ 5eV). However, by forming a composite material as in one aspect of the present invention, it is possible to overcome the problem of hole injectability from an electrode while maintaining excellent hole injectability into other organic compounds. .. Such properties of the composite material contribute to the reduction of the driving voltage when used in a light emitting element. In addition, since it has high translucency, it is possible to improve the luminous efficiency. Furthermore, it is considered that the deep HOMO level can prevent the accumulation of carriers in the light emitting element, so that the life can be extended.

Hereinafter, aspects of the present invention will be described with reference to specific examples.

(Embodiment 1) In the present embodiment, the composite material of one aspect of the present invention will be described.

The composite material of one aspect of the present invention is a composite material of an organic compound having a specific skeleton and an inorganic compound. The method for producing the composite material according to one aspect of the present invention is not limited, and for example, it can be formed by a co-deposited method in which the organic compound and the inorganic compound are simultaneously vapor-deposited. In the composite material of one aspect of the present invention, the mixing ratio of the organic compound and the inorganic compound is preferably about 8: 1 to 1: 2 (= organic compound: inorganic compound) in terms of mass ratio, and more preferably 4: 1 to 1: 1. 1 (= organic compound: inorganic compound). The mixing ratio can be controlled by adjusting the vapor deposition rates of the organic compound and the inorganic compound, respectively, when the composite material is formed by the co-evaporation method.

First, the organic compound that can be used in the composite material of one aspect of the present invention is an organic compound that has only a benzene ring and the number of the benzene rings is 4 or more and 25 or less. Further, the organic compound that can be used in the composite material of one aspect of the present invention is an organic compound having only a benzene ring and a molecular weight of 350 or more and 2000 or less.

The organic compound may have an alkyl group having 1 to 6 carbon atoms or a trialkylsilyl group as a substituent. Further, the organic compound may have a benzene ring crosslinked with silicon.

The composite material using the organic compound has high carrier transportability. In addition, it has high carrier injection properties into organic compounds. In addition, light absorption due to charge transfer interaction with an inorganic compound is unlikely to occur. In addition, it has high translucency.

The composite material using the organic compound not only suppresses the generation of light absorption based on the charge transfer interaction, but also can control the absorption peak of the organic compound itself to occur on the shorter wavelength side than the visible light region. High translucency can be obtained.

Since benzene is an aromatic hydrocarbon, it is an important conjugated ring for exhibiting carrier transportability (particularly hole transportability). At the same time, it is also a conjugated ring with a wide energy gap. Therefore, since the organic compound has only a benzene ring, it not only suppresses the generation of light absorption based on the charge transfer interaction, but also causes the absorption peak of the organic compound to occur on the shorter wavelength side than the visible light region. Since it can be controlled, a composite material having high translucency can be obtained by using the organic compound.

The method for producing the composite material is not particularly limited, but it is preferable to co-deposit the organic compound and the inorganic compound. In this case, it is desired that the organic compound is easily vaporized. Therefore, from the viewpoint of molecular weight, it is desirable that the molecular weight of the organic compound is 2000 or less. Further, when the composite material is formed by a wet process (a method of forming a film as a solution) by binding an alkyl chain or the like to the organic compound, the molecular weight may be 2000 or more.

From the results of experiments and studies conducted by the present inventors, when an aromatic hydrocarbon compound (for example, anthracene compound) and an inorganic compound are mixed, if the ratio of the inorganic compound is high, the compound is compounded. Although crystallization of the material can be suppressed, a slight absorption peak due to the charge transfer interaction between the skeleton of the aromatic hydrocarbon compound (for example, anthracene skeleton) and the inorganic compound may increase in the visible light region. On the other hand, as shown in one aspect of the present invention, an organic compound having only a benzene ring (the number of the benzene rings is 4 or more and 25 or less, or the molecular weight of the organic compound is 350 or more and 2000 or less. ) Is used, it is difficult for new absorption peaks to increase even when the proportion of inorganic compounds is high. Therefore, while maintaining high transmittance, crystallization of the composite material is suppressed and the film quality of the composite material is stabilized. Therefore, in the case of the composite material of one aspect of the present invention, even when it is desired to increase the ratio of the inorganic compound for the purpose of suppressing crystallization, the ratio of the organic compound and the inorganic compound is not restricted, and it is derived from the charge transfer interaction. It is possible to suppress the observation of the absorption peak in the visible light region. Therefore, the operation of film formation can be simplified. Specifically, the composite material of one aspect of the present invention is less likely to cause light absorption due to charge transfer interaction even in a film having a mass ratio of an organic compound to an inorganic compound of 4: 2, and is red from the visible light region. Almost no significant absorption peaks are observed up to the outer region.

The HOMO level of the organic compound contained in the composite material of one aspect of the present invention described above is preferably -5.7 eV or less as measured by photoelectron spectroscopy. As mentioned above, benzene has a very low HOMO level. Therefore, it is easy for the organic compound simple substance used in one aspect of the present invention to have a low HOMO level of -5.7 eV or less.

When an organic compound has a low HOMO level, it is considered to be excellent in hole injection into other organic compounds, but a conductive material such as Al or ITO (work function is about 3 to 5 eV). ) Is considered difficult to receive holes. However, by forming a composite material as in one aspect of the present invention, it is possible to overcome the problem of hole injectability from an electrode while maintaining excellent hole injectability into other organic compounds. .. Such properties of the composite material contribute to the reduction of the driving voltage when used in a light emitting element. In addition, since it has high translucency, it is possible to improve the luminous efficiency. Furthermore, since it is considered that the deep HOMO level can prevent the accumulation of carriers, a long life can be achieved.

The following structural formulas (100) to (112) show an example of an organic compound that can be used in the composite material of one aspect of the present invention.

<chemistry num="2"><img id="000003" he="193" wi="158" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></chemistry>

<chemistry num="3"><img id="000004" he="194" wi="158" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></chemistry>

<chemistry num="4"><img id="000005" he="69" wi="158" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></chemistry>

Subsequently, an inorganic compound that can be used in the composite material of one aspect of the present invention will be described.

An inorganic compound exhibiting electron acceptability with respect to the organic compound used in the composite material of one aspect of the present invention can be used. For example, iron (III) chloride and aluminum chloride are examples of inorganic compounds having high electron acceptability.

Alternatively, a transition metal oxide can be used as the inorganic compound in the composite material of one aspect of the present invention. Preferably, oxides of metals belonging to groups 4 to 8 in the periodic table of elements are desirable. In particular, titanium oxide, vanadium oxide, tantalum oxide, molybdenum oxide, tungsten oxide, renium oxide, ruthenium oxide, chromium oxide, zirconium oxide, hafnium oxide, and silver oxide are preferable. Of these, molybdenum oxide is a material that is particularly easy to handle because it is easy to deposit, has low hygroscopicity, and is stable.

It is considered that the transition metal oxide is not so high in electron acceptability (low reactivity) as compared with the above-mentioned strong Lewis acid such as iron (III) chloride. Further, as described above, in the composite material according to one aspect of the present invention, the occurrence of absorption based on the charge transfer interaction is small (or hardly occurs). From these facts, it is difficult to prove that the transition metal oxide acts as an electron acceptor in a general sense in the present invention. However, on the other hand, as will be described later in the examples, there is a fact that when an electric field is applied, a current that cannot be passed by the organic compound alone can be passed. Therefore, when a transition metal oxide is used in the composite material which is one aspect of the present invention, it is considered that carriers are easily generated at least by assisting the application of an electric field. Therefore, in the present specification, an inorganic compound (such as a transition metal oxide as described above) in a composite material is treated as having electron acceptability as long as carriers are generated at least by assisting electric field application.

As described above, the composite material of one aspect of the present invention is a material having a low HOMO level and high carrier transportability. Further, the composite material of one aspect of the present invention is a material having excellent carrier injection property into an organic compound. Further, the composite material of one aspect of the present invention is a material in which absorption based on charge transfer interaction is unlikely to occur. Further, the composite material of one aspect of the present invention is a material having high translucency.

Therefore, the composite material of one aspect of the present invention can be used for a light emitting element, a photoelectric conversion element, a semiconductor element such as a transistor, and the like.

Further, since the composite material of one aspect of the present invention is excellent in carrier transport property and carrier injection property into an organic compound, a low drive voltage can be realized by using it for a light emitting element or the like.

Further, since the composite material of one aspect of the present invention has translucency, high luminous efficiency can be realized by using it for a light emitting element or the like.

Further, since the composite material of one aspect of the present invention suppresses the accumulation of electric charges, it is possible to manufacture a device having a long life by using it as a light emitting device or the like.

Further, the composite material of one aspect of the present invention can be used for an organic thin film solar cell. Since the composite material of one aspect of the present invention is excellent in carrier transportability, it can be used for a carrier transport layer, a carrier injection layer, or a charge generation layer.

It should be noted that this embodiment can be appropriately combined with other embodiments.

(Embodiment 2) In the present embodiment, the light emitting device of one aspect of the present invention will be described with reference to FIG.

The light emitting element of the present embodiment is formed by sandwiching an EL layer (a layer containing a light emitting substance) between a pair of electrodes. The EL layer has at least a layer containing the composite material of one aspect of the present invention shown in the first embodiment and a light emitting layer. Further, the EL layer may have other layers. For example, a layer composed of a substance having high carrier injectability and a substance having high carrier transport property so that a light emitting region is formed at a position away from the electrode, that is, carriers are recombined at a site away from the electrode. May be provided. In the present specification, a layer composed of a substance having high carrier injection and a substance having high carrier transportability is also referred to as a functional layer having functions such as carrier injection and transport. As the functional layer, a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, or the like can be used. In the present embodiment, the layer containing the composite material of one aspect of the present invention is used as the hole injection layer.

Further, it is preferable to provide one or more layers (such as a hole transport layer) between the layer containing the composite material of one aspect of the present invention and the light emitting layer. As a result, quenching (decrease in efficiency) due to the excitation energy generated in the light emitting layer being transmitted to the layer containing the composite material can be suppressed, and a more efficient device can be obtained.

In the light emitting element shown in FIG. 1, an EL layer 102 is provided between a pair of electrodes of the first electrode 101 and the second electrode 108. The EL layer 102 is laminated on the first electrode 101 in the order of the hole injection layer 701, the hole transport layer 702, the light emitting layer 703, the electron transport layer 704, and the electron injection layer 705. In the light emitting device shown in the present embodiment, the first electrode 101 functions as an anode and the second electrode 108 functions as a cathode.

As the support of the light emitting element (see the substrate 100 in FIG. 1A), for example, a glass substrate, a quartz substrate, a plastic substrate, or the like can be used. Further, a flexible substrate may be used. The flexible substrate is a bendable (flexible) substrate, and examples thereof include a plastic substrate made of polycarbonate, polyarylate, and polyether sulfone. Further, a film (consisting of polypropylene, polyester, polyvinyl fluoride, polyvinyl chloride, etc.), an inorganic vapor-deposited film, or the like can also be used. Anything other than these may be used as long as it functions as a support for the light emitting element.

As the first electrode 101, various metals, alloys, conductive compounds, and mixtures thereof can be used. For example, ITO, indium oxide-tin oxide containing silicon or silicon oxide, indium Zinc Oxide, indium oxide containing tungsten oxide and zinc oxide (IWZO) and the like can be mentioned. These conductive metal oxide films are usually formed by sputtering, but may be produced by applying a sol-gel method or the like. For example, an indium oxide-zinc oxide film can be formed by a sputtering method using a target in which 1 to 20 wt% zinc oxide is added to indium oxide. Further, the IWZO film can be formed by a sputtering method using a target containing 0.5 to 5 wt% of tungsten oxide and 0.1 to 1 wt% of zinc oxide with respect to indium oxide. In addition, gold, platinum, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, nitrides of metal materials (for example, titanium nitride) and the like can be mentioned.

As the material of the first electrode 101, it is preferable to use a material having a large work function (work function is 4.0 eV or more). Regarding the light emitting element having a configuration in which the first electrode 101 and the layer containing the composite material of one aspect of the present invention are in contact with each other, the material used for the first electrode 101 is not limited to a material having a large work function. Materials with a small work function can also be used. For example, aluminum, silver, an alloy containing aluminum (for example, Al-Si) and the like can also be used.

The hole injection layer 701 is a layer containing the composite material of one aspect of the present invention.

The organic compound used in the composite material of one aspect of the present invention (see Embodiment 1) has a low HOMO level and good hole injection into the hole transport layer 702 and the light emitting layer 703. On the other hand, an injection barrier is formed between the first electrode 101 and the hole, and it is difficult for holes to be injected from the first electrode 101.

However, since the light emitting device of one aspect of the present invention uses the composite material of one aspect of the present invention for the hole injection layer 701, the injection barrier between the first electrode 101 and the hole injection layer 701 is relaxed. can do. Therefore, the injection barrier from the first electrode 101 to the light emitting layer 703 is small, an element having high carrier injection property can be realized, and a light emitting element having a low drive voltage can be provided.

Further, the composite material of one aspect of the present invention has high carrier generation efficiency and high carrier transportability. Therefore, by using the composite material of one aspect of the present invention, a light emitting device having high luminous efficiency can be realized.

In addition, the organic compound does not generate a large absorption peak in the visible light region. Further, the organic compound has a low HOMO level, and absorption based on a charge transfer interaction with the inorganic compound is unlikely to occur. Therefore, the composite material of one aspect of the present invention is less likely to have an absorption peak in the visible light region and has high translucency. Therefore, from this as well, it can be said that a light emitting device having high luminous efficiency can be realized by using the composite material of one aspect of the present invention.

Further, since the composite material of one aspect of the present invention can suppress the accumulation of electric charges, it is possible to provide a light emitting device having a long life.

The emission color of the light emitting device to which the composite material of one aspect of the present invention is applied is not limited. Further, the light emitting device to which the composite material of one aspect of the present invention is applied may be fluorescent or phosphorescent. The composite material of one aspect of the present invention can be suitably used for the hole injection layer in any of the light emitting devices because it absorbs the light emitting energy and hardly impairs the efficiency.

The hole transport layer 702 is a layer containing a substance having a high hole transport property. As the material of the hole transport layer 702, the organic compound used for the composite material of one aspect of the present invention may be used. Other substances with high hole transport properties include, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (abbreviation: NPB or α-NPD), N, N'-. Bis (3-Methylphenyl) -N, N'-Diphenyl- [1,1'-Biphenyl] -4,4'-Diamine (abbreviation: TPD), 4-Phenyl-4'-(9-Phenylfluoren-9) -Il) Triphenylamine (abbreviation: BPAFLP), 4,4'-bis [N- (9,9-dimethylfluoren-2-yl) -N-phenylamino] biphenyl (abbreviation: DFLDPBi), 4,4' Aromatic amine compounds such as -bis [N- (spiro-9,9'-bifluoren-2-yl) -N-phenylamino] biphenyl (abbreviation: BSPB) can be used. The substances mentioned here are mainly 10^-6cm²It is a substance with hole mobility of / Vs or more. However, any substance other than these may be used as long as it is a substance having a higher hole transport property than electrons. The layer containing the substance having a high hole transport property is not limited to a single layer, but may be a layer in which two or more layers made of the above substances are laminated.

In the hole transport layer 702, 4,4'-di (N-carbazolyl) biphenyl (abbreviation: CBP), 9- [4- (10-phenyl-9-anthracene) phenyl] -9H-carbazole (abbreviation: abbreviation) : CzPA), 9-phenyl-3- [4- (10-phenyl-9-anthril) phenyl] -9H-carbazole (abbreviation: PCzPA) and other carbazole derivatives and 2-tert-butyl-9,10- Using anthracene derivatives such as di (2-naphthyl) anthracene (abbreviation: t-BuDNA), 9,10-di (2-naphthyl) anthracene (abbreviation: DNA), 9,10-diphenylanthracene (abbreviation: DPAnth) May be.

In particular, since the organic compound in the composite material according to one aspect of the present invention has a low HOMO level, a material having a low HOMO level can also be applied to the hole transport layer. With such a configuration, it is possible to prevent the accumulation of electric charges at the interface between the light emitting layer and the hole transport layer, and it is possible to extend the life of the light emitting element. Specifically, the HOMO level of the hole transport layer is preferably -5.6 eV or less. From this point of view, the compound used for the hole transport layer is preferably a carbazole derivative, a dibenzothiophene derivative, a dibenzofuran derivative, an anthracene derivative or the like. Moreover, you may use the organic compound used for the composite material of one aspect of this invention. At this time, it is preferable to use the organic compound used for the composite material of one aspect of the present invention for the hole injection layer and the hole transport layer because the HOMO level becomes close to each other and the carrier injection barrier becomes smaller. In particular, when the organic compound used for the composite material of one aspect of the present invention used for the hole injection layer and the organic compound used for the hole transport layer are the same material, the hole injection property between these layers becomes good, which is preferable.

The hole transport layer 702 includes poly (N-vinylcarbazole) (abbreviation: PVK), poly (4-vinyltriphenylamine) (abbreviation: PVTPA), and poly [N- (4- {N'-[ 4- (4-Diphenylamino) phenyl] phenyl-N'-phenylamino} phenyl) methacrylamide] (abbreviation: PTPDMA), poly [N, N'-bis (4-butylphenyl) -N, N'-bis Polymer compounds such as (phenyl) benzidine] (abbreviation: Poly-TPD) can also be used.

The light emitting layer 703 is a layer containing a luminescent organic compound. As the luminescent organic compound, for example, a fluorescent compound that emits fluorescence or a phosphorescent compound that emits phosphorescence can be used.

Examples of the fluorescent compound that can be used in the light emitting layer 703 include N, N'-bis [4- (9H-carbazole-9-yl) phenyl] -N, N'-diphenyl as a blue light emitting material. Stillben-4,4'-diamine (abbreviation: YGA2S), 4- (9H-carbazole-9-yl) -4'-(10-phenyl-9-anthryl) triphenylamine (abbreviation: YGAPA), 4- ( Examples thereof include 10-phenyl-9-anthryl) -4'-(9-phenyl-9H-carbazole-3-yl) triphenylamine (abbreviation: PCBAPA). In addition, as green-based luminescent materials, N- (9,10-diphenyl-2-anthryl) -N, 9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCAPA), N- [9,10-bis (1,1'-biphenyl-2-yl) -2-anthril] -N, 9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCABPhA), N- (9,10-diphenyl-2-anthril) -N, N', N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N- [9,10-bis (1,1'-biphenyl-2-yl) -2-anthril]- N, N', N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA), N- [9,10-bis (1,1'-biphenyl-2-yl)]-N- [4- (9H-carbazole-9-yl) phenyl] -N-phenylanthracen-2-amine (abbreviation: 2YGABPhA), N, N, 9-triphenylanthracene-9-amine (abbreviation: DPhAPhA) and the like can be mentioned. Examples of the yellowish luminescent material include rubrene, 5,12-bis (1,1'-biphenyl-4-yl) -6,11-diphenyltetracene (abbreviation: BPT), and the like. In addition, as a red light emitting material, N, N, N', N'-tetrakis (4-methylphenyl) tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N, N , N',

The organic compound used in the composite material of one aspect of the present invention emits purple to blue fluorescence. Therefore, the organic compound used in the composite material of one aspect of the present invention can be used in the light emitting layer 703 as a fluorescent compound.

Further, as a phosphorescent compound that can be used for the light emitting layer 703, for example, as a blue light emitting material, bis [2- (4', 6'-difluorophenyl) pyridinato-N, C^2’] Iridium (III) Tetrakis (1-Pyrazolyl) Borato (abbreviation: FIr6), Bis [2- (4', 6'-difluorophenyl) Pyridinato-N, C^2’] Iridium (III) picolinate (abbreviation: FIrpic), bis {2- [3', 5'-bis (trifluoromethyl) phenyl] pyridinato-N, C^2’} Iridium (III) picolinate (abbreviation: [Ir (CF)₃ppy)₂(pic)]), Bis [2- (4', 6'-difluorophenyl) pyridinato-N, C^2’] Iridium (III) Acetylacetonate (abbreviation: FIr (acac)) and the like. In addition, as a greenish luminescent material, Tris (2-phenylpyridinato-N, C)^2’) Iridium (III) (abbreviation: [Ir (ppy)₃]), Bis (2-Phenylpyridinato-N, C^2’) Iridium (III) Acetylacetoneate (abbreviation: [Ir (ppy))₂(acac)]), Bis (1,2-diphenyl-1H-benzoimidazolato) Iridium (III) Acetylacetoneate (abbreviation: [Ir (pbi))₂(acac)]), bis (benzo [h] quinolinato) iridium (III) acetylacetoneate (abbreviation: [Ir (bzq))₂(acac)]), Tris (benzo [h] quinolinato) iridium (III) (abbreviation: [Ir (bzq))₃]) And so on. In addition, as a yellowish luminescent material, bis (2,4-diphenyl-1,3-oxazolato-N, C)^2’) Iridium (III) Acetylacetoneate (abbreviation: [Ir (dpo))₂(acac)]), bis [2- (4'-perfluorophenylphenyl) pyridinate] iridium (III) acetylacetonate (abbreviation: [Ir (p-PF-ph))₂(acac)]), bis (2-phenylbenzothiazolato-N, C^2’) Iridium (III) Acetylacetoneate (abbreviation: [Ir (bt))₂(acac)]), (Acetylacetoneto) bis [2,3-bis (4-fluorophenyl) -5-methylpyrazinato] iridium (III) (abbreviation: [Ir (Fdppr-Me))₂(acac)]), (Acetylacetoneto) Bis {2- (4-Methoxyphenyl) -3,5-Dimethylpyrazinato} Iridium (III) (Abbreviation: [Ir (dmmoppr))₂(acac)]) and so on. In addition, as an orange-based luminescent material, Tris (2-phenylquinolinato-N, C)^2’) Iridium (III) (abbreviation: [Ir (pq))₃]), Bis (2-Phenylquinolinato-N, C^2’) Iridium (III) Acetylacetoneate (abbreviation: [Ir (pq))₂(acac)]), (Acetylacetoneto) Bis (3,5-Dimethyl-2-phenylpyrazinato) Iridium (III) (Abbreviation: [Ir (mppr-Me))₂(acac)]), (Acetylacetoneto) Bis (5-isopropyl-3-methyl-2-phenylpyrazinato) Iridium (III) (Abbreviation: [Ir (mppr-iPr))₂(acac)]) and so on. In addition, as a red-based luminescent material, bis [2- (2'-benzo [4,5-α] thienyl) pyridinato-N, C^3’] Iridium (III) Acetylacetoneate (abbreviation: [Ir (btp))₂(acac)]), Bis (1-Phenylisoquinolinato-N, C^2’) Iridium (III) Acetylacetoneate (abbreviation: [Ir (piq))₂(acac)]), (Acetylacetoneto) bis [2,3-bis (4-fluorophenyl) quinoxalinato] Iridium (III) (abbreviation: [Ir (Fdpq))₂(acac)]), (Acetylacetoneto) Bis (2,3,5-triphenylpyrazinato) Iridium (III) (Abbreviation: [Ir (tppr))₂(acac)]), (dipivaloylmethanato) bis (2,3,5-triphenylpyrazinato) iridium (III) (abbreviation: [Ir (tppr))₂(dpm)]), 2,3,7,8,12,13,17,18-octaethyl-21H, 23H-porphyrin platinum (II) (abbreviation: PtOEP) and other organometallic complexes can be mentioned. In addition, tris (acetylacetonato) (monophenanthroline) terbium (III) (abbreviation: Tb (acac)₃(Phen)), Tris (1,3-diphenyl-1,3-propanedionat) (monophenanthroline) Europium (III) (abbreviation: Eu (DBM))₃(Phen)), Tris [1- (2-tenoyl) -3,3,3-trifluoroacetonato] (monophenanthroline) Europium (III) (abbreviation: Eu (TTA))₃Rare earth metal complexes such as (Phen)) can be used as phosphorescent compounds because they emit light from rare earth metal ions (electronic transitions between different multiplicities).

The light emitting layer 703 may have a configuration in which the above-mentioned luminescent organic compound (guest material) is dispersed in another substance (host material). As the host material, various materials can be used, and it is preferable to use a substance having a higher minimum empty orbital level (LUMO level) and a lower HOMO level than the guest material. When the guest material is a fluorescent compound, the singlet excitation energy level (S1 level) is preferably high, and when the guest material is a phosphorescent compound, the triplet excitation energy level (T1 level) is preferably high.

The organic compound used in the composite material of one aspect of the present invention has a high LUMO level, a low HOMO level, and a high S1 level and a high T1 level, respectively. Therefore, it can be used as a host material for a fluorescent compound that emits visible light or a host material for a phosphorescent compound.

Specific examples of the host material include tris (8-quinolinolato) aluminum (III) (abbreviation: Alq) and tris (4-methyl-8-quinolinolato) aluminum (III) (abbreviation: Almq).₃), Bis (10-Hydroxybenzo [h] quinolinato) Beryllium (II) (abbreviation: BeBq₂), Bis (2-methyl-8-quinolinolato) (4-phenylphenorato) Aluminum (III) (abbreviation: BAlq), Bis (8-quinolinolato) Zinc (II) (abbreviation: Znq), Bis [2- ( 2-benzoxazolyl) Phenolato] Zinc (II) (abbreviation: Zn (BOX))₂), Bis [2- (2-benzothiazolyl) phenolato] Zinc (II) (abbreviation: Zn (BTZ))₂) And other metal complexes, 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis [5- (p) -tert-butylphenyl) -1,3,4-oxadiazol-2-yl] benzene (abbreviation: OXD-7), 3- (4-biphenylyl) -4-phenyl-5- (4-tert-butyl) Phenyl) -1,2,4-triazole (abbreviation: TAZ), 2,2', 2''-(1,3,5-benzenetriyl) Tris (1-phenyl-1H-benzoimidazole) (abbreviation: Heterocyclic compounds such as TPBI), vasofenantroline (abbreviation: BPhen), vasocuproin (abbreviation: BCP), 9- [4- (10-phenyl-9-anthryl) phenyl] -9H-carbazole (abbreviation: CzPA), 3,6-Diphenyl-9- [4- (10-Phenyl-9-anthryl) phenyl] -9H-carbazole (abbreviation: DPCzPA), 9,10-bis (3,5-diphenylphenyl) anthracene (abbreviation: DPPA) ), 9,10-Di (2-naphthyl) anthracene (abbreviation: DNA), 2-tert-butyl-9,10-di (2-naphthyl) anthracene (abbreviation: t-BuDNA), 9,9'-biantolyl (Abbreviation: BANT), 9,9'-(Stilben-3,3'-Zyle) Diphenantren (Abbreviation: DPNS), 9,9'-(Stilben-4,4'-Zyle) Diphenantren (Abbreviation: DPNS2) ), 3,3', 3''-(benzene-1,3,5-triyl) tripylene (abbreviation: TPB3), 9,10-diphenylanthracene (abbreviation: DPAnth), 6,12-dimethoxy-5,11 -Condensed aromatic compounds such as -diphenylchrycene, N, N-diphenyl-9- [4- (10-phenyl-9-anthryl) phenyl] -9H-carbazole-3-amine (abbreviation: CzA1PA), 4- (10) -Phenyl-9-anthryl) Triphenylamine (abbreviation: DPhPA), N,9-Diphenyl-N- [4- (10-Phenyl-9-anthryl) phenyl] -9H-carbazole-3-amine (abbreviation: PCAPA), N, 9-diphenyl-N- {4- [4- (10) -Phenyl-9-anthryl) Phenyl] Phenyl} -9H-carbazole-3-amine (abbreviation: PCAPBA), N- (9,10-diphenyl-2-anthryl) -N, 9-diphenyl-9H-carbazole-3 -Amines (abbreviation: 2PCAPA), NPB (or α-NPD), TPD, DFLDPBi, BSPB and other aromatic amine compounds can be used.

In addition, a plurality of types of host materials can be used. For example, in order to suppress crystallization, a substance that suppresses crystallization, such as rubrene, may be further added. In addition, NPB, Alq, or the like may be further added in order to transfer energy to the guest material more efficiently.

The crystallization of the light emitting layer 703 can be suppressed by having the guest material dispersed in the host material. In addition, it is possible to suppress concentration quenching due to a high concentration of guest material.

Further, a polymer compound can be used as the light emitting layer 703. Specifically, as a blue-based luminescent material, poly (9,9-dioctylfluorene-2,7-diyl) (abbreviation: PFO), poly [(9,9-dioctylfluorene-2,7-diyl)- co- (2,5-dimethoxybenzene-1,4-diyl)] (abbreviation: PF-DMOP), poly {(9,9-dioctylfluorene-2,7-diyl)-co- [N, N'- Di- (p-butylphenyl) -1,4-diaminobenzene]} (abbreviation: TAB-PFH) and the like can be mentioned. In addition, as green-based luminescent materials, poly (p-phenylene vinylene) (abbreviation: PPV), poly [(9,9-dihexylfluorene-2,7-diyl) -alt-co- (benzo [2,1,1) 3] Thiadiazole-4,7-diyl)] (abbreviation: PFBT), poly [(9,9-dioctyl-2,7-divinylene fluoreneylene) -alt-co- (2-methoxy-5- (2) -Ethylhexyloxy) -1,4-phenylene)] and the like. In addition, as orange to red luminescent materials, poly [2-methoxy-5- (2'-ethylhexoxy) -1,4-phenylene vinylene] (abbreviation: MEH-PPV), poly (3-butylthiophene-2, 5-Diyl) (abbreviation: R4-PAT), poly {[9,9-dihexyl-2,7-bis (1-cyanovinylene) phenylylene] -alt-co- [2,5-bis (N, N'- Diphenylamino) -1,4-phenylene]}, poly {[2-methoxy-5- (2-ethylhexyloxy) -1,4-bis (1-cyanovinylene phenylene)]-alt-co- [2, 5-Bis (N, N'-diphenylamino) -1,4-phenylene]} (abbreviation: CN-PPV-DPD) and the like can be mentioned.

Further, by providing a plurality of light emitting layers and making the light emitting colors of the respective light emitting layers different, it is possible to obtain light emission of a desired color as the entire light emitting element. For example, in a light emitting element having two light emitting layers, a light emitting element that emits white light as a whole by making the light emitting color of the first light emitting layer and the light emitting color of the second light emitting layer have a complementary color relationship. It is also possible to obtain. The complementary color refers to the relationship between colors that become achromatic when mixed. That is, white light can be obtained by mixing light obtained from a substance that emits a complementary color. The same applies to a light emitting element having three or more light emitting layers.

The electron transport layer 704 is a layer containing a substance having a high electron transport property. Examples of substances with high electron transport properties include Alq and Almq.₃, BeBq₂, BAlq and the like, and examples thereof include metal complexes having a quinoline skeleton or a benzoquinoline skeleton. In addition, Zn (BOX)₂, Zn (BTZ)₂Oxazole-based and thiazole-based ligands such as metal complexes can also be used. Further, in addition to the metal complex, PBD, OXD-7, TAZ, BPhen, BCP and the like can also be used. The substances mentioned here are mainly 10^-6cm²It is a substance with electron mobility of / Vs or more. Further, the electron transport layer is not limited to a single layer, but may be a layer in which two or more layers made of the above substances are laminated.

The electron injection layer 705 is a layer containing a substance having a high electron injection property. Alkali metals such as lithium, cesium, calcium, lithium fluoride, cesium fluoride, calcium fluoride, lithium oxide and the like, alkaline earth metals, or compounds thereof can be used for the electron injection layer 705. In addition, rare earth metal compounds such as erbium fluoride can be used. Further, the substance constituting the electron transport layer 704 described above can also be used.

The hole injection layer 701, the hole transport layer 702, the light emitting layer 703, the electron transport layer 704, and the electron injection layer 705 described above are described by a vapor deposition method (including a vacuum vapor deposition method), an inkjet method, a coating method, and the like, respectively. It can be formed by a method.

In the light emitting element shown in FIG. 2A, an EL layer 102 is provided on the substrate 100 between a pair of electrodes of the first electrode 101 and the second electrode 108. The EL layer 102 has a hole injection layer 701, a hole transport layer 702, a light emitting layer 703, an electron transport layer 704, and an electron injection layer 705. The light emitting element in FIG. 2A is a second electrode 108 that functions as a cathode on the substrate 100, and an electron injection layer 705, an electron transport layer 704, and a light emitting layer 703 that are sequentially laminated on the second electrode 108. It is composed of a hole transport layer 702, a hole injection layer 701, and a first electrode 101 provided on the hole transport layer 702 and functioning as an anode.

Further, by making the emission color of each EL layer different, it is possible to obtain emission of a desired color as the entire light emitting element. For example, in a light emitting element having two EL layers, a light emitting element that emits white light as a whole by making the light emitting color of the first EL layer and the light emitting color of the second EL layer have a complementary color relationship. It is also possible to obtain. The same applies to a light emitting element having three or more EL layers.

As shown in FIG. 1 (B), a plurality of EL layers may be laminated between the first electrode 101 and the second electrode 108. In this case, it is preferable to provide a charge generation layer 803 between the laminated first EL layer 800 and the second EL layer 801. The charge generation layer 803 can be formed by using the composite material of one aspect of the present invention. The composite material of one aspect of the present invention has high carrier generation efficiency and high hole transportability when a voltage is applied. Therefore, by using the composite material of one aspect of the present invention, a light emitting device having a low drive voltage can be realized. In addition, a light emitting element having high luminous efficiency can be realized.

Also in this case, the organic compound used for the composite material of one aspect of the present invention is preferably used for the hole transport layer in contact with the layer containing the composite material of one aspect of the present invention and the light emitting layer in contact with the hole transport layer. be able to.

In addition, the organic compound is unlikely to have an absorption peak in the visible light region. In addition, the organic compound has a low HOMO level, and absorption based on charge transfer interaction with the inorganic compound is unlikely to occur. Therefore, the composite material of one embodiment of the present invention has an absorption peak in the visible light region. It is hard to occur and has high translucency. Therefore, from this as well, it can be said that a light emitting device having high luminous efficiency can be realized by using the composite material of one aspect of the present invention.

Further, the charge generation layer 803 may have a laminated structure of a layer made of the composite material of one aspect of the present invention and a layer made of another material. In this case, as the layer made of another material, a layer containing an electron donating substance and a substance having a high electron transporting property, a layer made of a transparent conductive film, or the like can be used. A light emitting element having such a configuration is unlikely to cause problems such as energy transfer and quenching, and it is easy to make a light emitting element having both high luminous efficiency and long life by expanding the range of material selection. It is also easy to obtain phosphorescence emission from one EL layer and fluorescence emission from the other. This structure can be used in combination with the above-mentioned structure of the EL layer.

Similarly, as shown in FIG. 2B, a light emitting element in which three or more EL layers 802 are laminated can also be applied. A long-life element that emits light with high brightness while maintaining a low current density by arranging a plurality of EL layers with a charge generation layer sandwiched between a pair of electrodes, such as the light emitting element according to the present embodiment. Can be realized.

As shown in FIG. 1 (C), the EL layer has a hole injection layer 701, a hole transport layer 702, a light emitting layer 703, and an electron transport layer 704 between the first electrode 101 and the second electrode 108. , The electron injection buffer layer 706, the electron relay layer 707, and the composite material layer 708 in contact with the second electrode 108 may be provided.

It is preferable to provide the composite material layer 708 in contact with the second electrode 108 because the damage to the EL layer 102 can be reduced particularly when the second electrode 108 is formed by using the sputtering method. As the composite material layer 708, the composite material of one aspect of the present invention can be used.

Further, since the composite material layer 708 functions as a charge generation layer, carriers can be satisfactorily injected into the electron relay layer 707 from the second electrode 108 via the composite material layer 708.

Further, by providing the electron injection buffer layer 706, the injection barrier between the composite material layer 708 and the electron transport layer 704 can be relaxed, so that the electrons generated in the composite material layer 708 can be easily transferred to the electron transport layer 704. Can be injected into.

The electron injection buffer layer 706 includes alkali metals, alkaline earth metals, rare earth metals, and compounds thereof (alkali metal compounds (including oxides such as lithium oxide, halides, and carbonates such as lithium carbonate and cesium carbonate). , Alkali earth metal compounds (including oxides, halides and carbonates), or rare earth metal compounds (including oxides, halides and carbonates)) and other highly electron-injectable substances can be used. Is.

When the electron injection buffer layer 706 is formed by containing a substance having a high electron transport property and a donor substance, the donor has a mass ratio of 0.001 or more and 0.1 or less with respect to the substance having a high electron transport property. It is preferable to add a sex substance. The donor substances include alkali metals, alkaline earth metals, rare earth metals, and compounds thereof (alkali metal compounds (including oxides such as lithium oxide, halides, and carbonates such as lithium carbonate and cesium carbonate). , Alkali earth metal compounds (including oxides, halides, carbonates), or rare earth metal compounds (including oxides, halides, carbonates), as well as tetrathianaphthalcene (abbreviation: TTN), Organic compounds such as nickerosen and decamethyl nickerosen can also be used. As the substance having high electron transportability, it can be formed by using the same material as the material of the electron transport layer 704 described above.

Further, it is preferable to form an electron relay layer 707 between the electron injection buffer layer 706 and the composite material layer 708. The electron relay layer 707 does not necessarily have to be provided, but by providing the electron relay layer 707 having high electron transportability, electrons can be quickly sent to the electron injection buffer layer 706.

The structure in which the electron relay layer 707 is sandwiched between the composite material layer 708 and the electron injection buffer layer 706 consists of an acceptor substance contained in the composite material layer 708 and a donor substance contained in the electron injection buffer layer 706. It is a structure that is less susceptible to interaction and less likely to interfere with each other's functions. Therefore, it is possible to suppress an increase in the drive voltage.

The electron relay layer 707 contains a substance having high electron transportability, and the LUMO level of the substance having high electron transportability is contained in the LUMO level of the acceptor substance contained in the composite material layer 708 and the electron transport layer 704. It is formed so as to be between the LUMO level of a substance with high electron transportability. When the electron relay layer 707 contains a donor substance, the donor level of the donor substance is also the LUMO level of the acceptor substance contained in the composite material layer 708 and the electron transport contained in the electron transport layer 704. Try to be between the LUMO level of the highly sexual substance. As a specific energy level value, the LUMO level of the substance having high electron transport property contained in the electron relay layer 707 is preferably -5.0 eV or more, preferably -5.0 eV or more and -3.0 eV or less.

As the substance having high electron transport property contained in the electron relay layer 707, it is preferable to use a phthalocyanine-based material or a metal complex having a metal-oxygen bond and an aromatic ligand.

Specific examples of the phthalocyanine-based material contained in the electron relay layer 707 include CuPc, SnPc (Phthalocyanine tin (II) complex), ZnPc (Phthalocyanine zinc complex), CoPc (Cobalt (II) phthalocyanine, β-form), and FePc. It is preferable to use either (Phthalocyanine Iron) or PhO-VOPc (Vanadyl 2,9,16,23-tetraphenoxy-29H, 31H-phthalocyanine).

As the metal complex having a metal-oxygen bond and an aromatic ligand contained in the electron relay layer 707, it is preferable to use a metal complex having a metal-oxygen double bond. Since the metal-oxygen double bond has acceptor properties (property to easily accept electrons), electron transfer (transfer) becomes easier. Moreover, the metal complex having a metal-oxygen double bond is considered to be stable. Therefore, by using a metal complex having a metal-oxygen double bond, it becomes possible to drive the light emitting element more stably at a low voltage.

A phthalocyanine-based material is preferable as the metal complex having a metal-oxygen bond and an aromatic ligand. Specifically, any of VOPc (Vanadyl phthalocyanine), SnOPc (Phthalocyanine tin (IV) oxide complex) and TiOPc (Phthalocyanine titanium oxide complex) has a molecular structure in which a metal-oxygen double bond is transferred to another molecule. On the other hand, it is preferable because it easily acts and has high acceptability.

The phthalocyanine-based material described above preferably has a phenoxy group. Specifically, a phthalocyanine derivative having a phenoxy group, such as PhO-VOPc, is preferable. Phthalocyanine derivatives with phenoxy groups are soluble in solvents. Therefore, it has an advantage that it is easy to handle in forming a light emitting element. Further, since it is soluble in a solvent, it has an advantage that maintenance of the apparatus used for film formation becomes easy.

The electron relay layer 707 may further contain a donor substance. Donor substances include alkali metals, alkaline earth metals, rare earth metals and their compounds (including alkali metal compounds (including oxides such as lithium oxide, halides, carbonates such as lithium carbonate and cesium carbonate), and alkaline soil. In addition to metal compounds (including oxides, halides and carbonates) or rare earth metal compounds (including oxides, halides and carbonates), tetrathianaphthalcene (abbreviation: TTN), nickerosen, deca Organic compounds such as methylnickerosen can be used. By including these donor substances in the electron relay layer 707, the movement of electrons becomes easy, and the light emitting element can be driven at a lower voltage.

When the electron relay layer 707 contains a donor substance, in addition to the above-mentioned materials, a substance having a LUMO level higher than the acceptor level of the acceptor substance contained in the composite material layer 708 is used as a substance having high electron transport property. Can be used. As a specific energy level, it is preferable to use a substance having a LUMO level in the range of -5.0 eV or more, preferably -5.0 eV or more and -3.0 eV or less. Examples of such a substance include a perylene derivative and a nitrogen-containing condensed aromatic compound. Since the nitrogen-containing condensed aromatic compound is stable, it is a preferable material as a material used for forming the electron relay layer 707.

Specific examples of the perylene derivative include 3,4,9,10-perylenetetracarboxylic dianhydride (abbreviation: PTCDA), 3,4,9,10-perylenetetracarboxylic bisbenzoimidazole (abbreviation: PTCBI), N, N'-dioctyl-3,4,9,10-perylenetetracarboxylic dianimide (abbreviation: PTCDI-C8H), N, N'-dihexyl-3,4,9,10-perylenetetracarboxylic dianimide (abbreviation) : Hex PTC) etc.

Specific examples of the nitrogen-containing condensed aromatic compound include pyradino [2,3-f] [1,10] phenanthroline-2,3-dicarbonitrile (abbreviation: PPDN), 2,3,6,7, 10,11-Hexacyano-1,4,5,8,9,12-Hexaazatriphenylene (abbreviation: HAT (CN))₆), 2,3-Diphenylpyrazine [2,3-b] pyrazine (abbreviation: 2PYPR), 2,3-bis (4-fluorophenyl) pyrazine [2,3-b] pyrazine (abbreviation: F2PYPR), etc. Can be mentioned.

In addition, 7,7,8,8-tetracyanoquinodimethane (abbreviation: TCNQ), 1,4,5,8-naphthalenetetracarboxylic dianhydride (abbreviation: NTCDA), perfluoropentacene, copper hexane Decafluorophthalocyanine (abbreviation: F)₁₆CuPc), N, N'-bis (2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctyl) -1,4, 5,8-Naphthalenetetracarboxylic dianimide (abbreviation: NTCDI-C8F), 3', 4'-dibutyl-5,5''-bis (dicyanomethylene) -5,5''-dihydro-2,2': 5', 2''-terthiophene) (abbreviation: DCMT), metanofullerene (eg [6,6] -phenyl C₆₁Methyl butyrate) and the like can be used.

When the electron relay layer 707 contains a donor substance, the electron relay layer 707 may be formed by a method such as co-evaporation of a substance having a high electron transport property and the donor substance.

The hole injection layer 701, the hole transport layer 702, the light emitting layer 703, and the electron transport layer 704 may be formed by using the above-mentioned materials, respectively. In particular, the hole injection layer 701 may be a composite material of one aspect of the present invention. Further, as the hole transport layer 702 and the light emitting layer 703, the organic compound used in the composite material of one aspect of the present invention can be preferably used.

It should be noted that this embodiment can be appropriately combined with other embodiments.

(Embodiment 3) In the present embodiment, a light emitting device having a light emitting element according to one aspect of the present invention will be described with reference to FIG. Note that FIG. 3 (A) is a top view showing a light emitting device, and FIG. 3 (B) is a cross-sectional view of FIG. 3 (A) cut with AB and CD.

The light emitting device of the present embodiment includes a source side drive circuit 401 and a gate side drive circuit 403, a pixel unit 402, a sealing substrate 404, a sealing material 405, and an FPC (flexible printed circuit) 409, which are drive circuit units. And the element substrate 410. The inside surrounded by the sealing material 405 is a space.

The routing wiring 408 is a wiring for transmitting signals input to the source side drive circuit 401 and the gate side drive circuit 403, and is a video signal, a clock signal, a start signal, a reset signal, etc. from the FPC 409 which is an external input terminal. To receive. Although only the FPC is shown here, a printed wiring board (PWB) may be attached to the FPC. The light emitting device in the present specification includes not only the light emitting device main body but also a state in which an FPC or PWB is attached to the light emitting device main body.

The drive circuit unit and the pixel unit are formed on the element substrate 410 shown in FIG. 3 (A). In FIG. 3 (B), the source side drive circuit 401, which is the drive circuit unit, and the pixel unit 402 are included. One pixel is shown.

The source side drive circuit 401 is formed as a CMOS circuit in which an n-channel type TFT423 and a p-channel type TFT424 are combined. Further, the drive circuit may be formed by various CMOS circuits, MIMO circuits or MIMO circuits formed by TFT. Further, in the present embodiment, the driver integrated type in which the drive circuit is formed on the substrate is shown, but it is not always necessary, and the drive circuit can be formed on the outside instead of on the substrate.

Further, the pixel portion 402 is formed by a plurality of pixels including a switching TFT 411, a current control TFT 412, and a first electrode 413 electrically connected to the drain thereof. An insulator 414 is formed so as to cover the end portion of the first electrode 413. Here, it is formed by using a positive photosensitive acrylic resin film.

Further, in order to improve the covering property, a curved surface having a curvature is formed at the upper end portion or the lower end portion of the insulator 414. For example, when positive photosensitive acrylic is used as the material of the insulating material 414, it is preferable that only the upper end portion of the insulating material 414 has a curved surface having a radius of curvature (0.2 μm to 3 μm). Further, as the insulator 414, either a negative type that becomes insoluble in the etchant by irradiation with light or a positive type that becomes soluble in the etchant by irradiation with light can be used.

An EL layer 416 and a second electrode 417 are formed on the first electrode 413, respectively. Here, as the material used for the first electrode 413 that functions as an anode, it is desirable to use a material having a large work function. For example, an ITO film, an indium tin oxide film containing silicon, an indium oxide film containing 2 to 20 wt% zinc oxide, a titanium nitride film, a chromium film, a tungsten film, a Zn film, a single layer film such as a Pt film. In addition, a laminated structure of a titanium nitride film and a film containing aluminum as a main component, a three-layer structure of a titanium nitride film, a film containing aluminum as a main component, and a titanium nitride film can be used. In addition, when the laminated structure is used, the resistance as wiring is low, and good ohmic contact can be obtained.

The EL layer 416 is formed by various methods such as a thin-film deposition method using a thin-film deposition mask, a droplet ejection method such as an inkjet method, a printing method, and a spin coating method. The EL layer 416 contains the composite material of one aspect of the invention shown in Embodiment 1. Further, the other material constituting the EL layer 416 may be a low molecular weight material, an oligomer, a dendrimer, or a high molecular weight material.

Further, as a material used for the second electrode 417 formed on the EL layer 416 and functioning as a cathode, a material having a small work function (Al, Mg, Li, Ca, or an alloy or compound thereof, Mg-Ag, etc. It is preferable to use Mg-In, Al-Li, etc.). In order for the light generated in the EL layer 416 to pass through the second electrode 417, a thin metal thin film and a transparent conductive film (ITO, 2 to 20 wt% oxidation) are used as the second electrode 417. It is preferable to use a laminate with indium oxide containing zinc, silicon or indium oxide containing silicon oxide-tin oxide, zinc oxide, etc.).

Further, by bonding the sealing substrate 404 to the element substrate 410 with the sealing material 405, the light emitting element 418 is provided in the space 407 surrounded by the element substrate 410, the sealing substrate 404, and the sealing material 405. There is. The space 407 is filled with a filler, which may be filled with an inert gas (nitrogen, argon, etc.) or a sealing material 405.

It is preferable to use an epoxy resin for the sealing material 405. Further, it is desirable that these materials are materials that do not allow moisture or oxygen to permeate as much as possible. Further, as a material used for the sealing substrate 404, in addition to a glass substrate and a quartz substrate, a plastic substrate made of FRP (Fiberglass-Reinforced Plastics), PVF (polyvinyl fluoride), polyester, acrylic or the like can be used.

As described above, an active matrix type light emitting device having the light emitting element of one aspect of the present invention can be obtained.

Further, the light emitting device of the present invention can be used not only for the above-mentioned active matrix type light emitting device but also for a passive matrix type light emitting device. FIG. 4 shows a perspective view and a cross-sectional view of a passive matrix type light emitting device using the light emitting element of the present invention. Note that FIG. 4 (A) is a perspective view showing a light emitting device, and FIG. 4 (B) is a cross-sectional view of FIG. 4 (A) cut by XY.

In FIG. 4, an EL layer 504 is provided between the first electrode 502 and the second electrode 503 on the substrate 501. The end of the first electrode 502 is covered with an insulating layer 505. A partition layer 506 is provided on the insulating layer 505. The side wall of the partition wall layer 506 has an inclination such that the distance between one side wall and the other side wall becomes narrower as it gets closer to the substrate surface. That is, the cross section in the short side direction of the partition wall layer 506 is trapezoidal, and the bottom side (the side facing the same direction as the surface direction of the insulating layer 505 and in contact with the insulating layer 505) is the upper side (the surface of the insulating layer 505). It faces in the same direction as the direction, and is shorter than the side that does not contact the insulating layer 505). By providing the partition wall layer 506 in this way, it is possible to prevent defects in the light emitting element due to crosstalk or the like.

From the above, it is possible to obtain a passive matrix type light emitting device having the light emitting element of one aspect of the present invention.

FIG. 5 shows an example of a light emitting device to which one aspect of the present invention is applied. FIG. 5 (A) is a top view showing a light emitting device, and FIGS. 5 (B) and 5 (C) are cross-sectional views of FIG. 5 (A) cut between EFs.

The light emitting device 900 shown in FIGS. 5A to 5C includes a light emitting element 908 (first electrode 101, EL layer 102, and second electrode 108) on the first substrate 901. The light emitting element 908 can be formed by using the material shown in the second embodiment. The EL layer 102 contains the composite material of one aspect of the present invention.

The light emitting device of the present embodiment has a structure in which a light emitting element emits light in the upper direction (also referred to as a top emission structure), a structure in which light is emitted in the upper and lower directions (also referred to as a dual emission structure), and a lower direction. Any structure that emits light (also called a bottom emission structure) can be applied.

Figure 5 (B) shows a light emitting device with a bottom emission structure.

The light emitting device shown in FIG. 5B has a first electrode 101 on the first substrate 901, an EL layer 102 on the first electrode 101, and a second electrode on the EL layer 102. Has 108.

The first terminal 903 is electrically connected to the auxiliary wiring 910 and the first electrode 101, and the second terminal 904 is electrically connected to the second electrode 108. Further, an insulating layer 909 is formed between the ends of the first electrode 101 and the second electrode 108, and between the auxiliary wiring 910 and the EL layer 102. Although FIG. 5B shows a configuration in which the first electrode 101 is formed on the auxiliary wiring 910, the auxiliary wiring 910 may be formed on the first electrode 101.

The first substrate 901 and the second substrate 902 are bonded to each other by the sealing material 912. Further, the desiccant 911 may be provided between the first substrate 901 and the second substrate 902.

Further, the upper part, the lower part, or both of the first substrate 901 may have a light extraction structure. As the light extraction structure, a concavo-convex structure may be provided at the interface through which light is transmitted from the side having a high refractive index to the side having a low refractive index. Specifically, as shown in FIG. 5 (B), a light extraction structure 913a having a fine concavo-convex structure is provided between the light emitting element 908 having a high refractive index and the first substrate 901 having a lower refractive index. A configuration in which a light extraction structure 913b having a concavo-convex structure is provided between the first substrate 901 and the atmosphere can be mentioned.

However, in the light emitting element, if the first electrode 101 has irregularities, a leak current may occur in the EL layer 102 formed on the first electrode 101. Therefore, in the present embodiment, the flattening layer 914 having a refractive index equal to or higher than the refractive index of the EL layer 102 is provided in contact with the light extraction structure 913a. As a result, the first electrode 101 can be made into a flat film, and the generation of leakage current in the EL layer due to the unevenness of the first electrode 101 can be suppressed. Further, since the light extraction structure 913a is provided at the interface between the flattening layer 914 and the first substrate 901, the light that cannot be extracted into the atmosphere due to the influence of total reflection is reduced, and the light extraction efficiency of the light emitting device is improved. Can be done.

In FIG. 5B, the first substrate 901, the light extraction structure 913a, and the light extraction structure 913b are shown as different elements, but the present invention is not limited to this. Two or all of these may be integrally formed. Further, the light extraction structure 913a may be entirely formed inside the seal region.

Figure 5 (C) shows a light emitting device with a top emission structure.

The light emitting device shown in FIG. 5C has a second electrode 108 on the first substrate 901, an EL layer 102 on the second electrode 108, and a first electrode on the EL layer 102. Has 101.

The first terminal 903 is electrically connected to the second electrode 108, and the second terminal 904 is electrically connected to the first electrode 101. An insulating layer 909 is formed at the ends of the first electrode 101 and the second electrode 108.

The first substrate 901 and the second substrate 902 are bonded to each other by the sealing material 912. Further, the auxiliary wiring may be formed on the first electrode 101. Further, the desiccant 911 may be provided between the first substrate 901 and the second substrate 902. The desiccant 911 is preferably provided at a position that does not overlap with the light emitting region of the light emitting element. Alternatively, it is preferable to use a desiccant that transmits the light of the light emitting element.

The shape of the light emitting device 900 shown in FIG. 5 (A) is octagonal, but the present invention is not limited to this. The light emitting device 900 and the light emitting element 908 may have other polygonal or curved shapes. In particular, the shape of the light emitting device 900 is preferably a triangle, a quadrangle, a regular hexagon, or the like. This is because a plurality of light emitting devices 900 can be provided in a limited area without any gap. Further, it is possible to form the light emitting device 900 by effectively utilizing the limited substrate area. Further, the number of elements formed on the substrate is not limited to one, and a plurality of elements may be provided.

As the material of the first substrate 901 and the second substrate 902, a translucent material such as glass, quartz, or an organic resin can be used. At least one of the first substrate 901 and the second substrate 902 transmits the light emitted by the light emitting element.

When an organic resin is used as the substrate, the organic resin may be, for example, a polyester resin such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), a polyacrylic nitrile resin, a polyimide resin, a polymethyl methacrylate resin, or a polycarbonate (PC) resin. , Polyether sulfone (PES) resin, polyamide resin, cycloolefin resin, polystyrene resin, polyamideimide resin, polyvinyl chloride resin and the like can be used. Further, a substrate in which glass fibers are impregnated with an organic resin or a substrate in which an inorganic filler is mixed with an organic resin can also be used.

Since all of the light emitting devices shown in the present embodiment are formed by using the light emitting element of one aspect of the present invention, it is possible to obtain a light emitting device having low power consumption.

It should be noted that this embodiment can be appropriately combined with other embodiments.

(Embodiment 4) In the present embodiment, examples of various electronic devices and lighting fixtures completed by using the light emitting device, which is an aspect to which the present invention is applied, will be described with reference to FIGS. 6 and 7.

Electronic devices to which a light emitting device is applied include, for example, television devices (also referred to as televisions or television receivers), monitors for computers, digital cameras, digital video cameras, digital photo frames, mobile phones (mobile phones, mobile phones). (Also called a telephone device), a portable game machine, a mobile information terminal, a sound reproduction device, a large game machine such as a pachinko machine, and the like. Specific examples of these electronic devices and lighting fixtures are shown in FIG.

FIG. 6A shows an example of a television device. In the television device 7100, the display unit 7103 is incorporated in the housing 7101. The display unit 7103 can display an image, and the light emitting device can be used for the display unit 7103. Further, here, a configuration in which the housing 7101 is supported by the stand 7105 is shown.

The operation of the television device 7100 can be performed by the operation switch provided in the housing 7101 or the separate remote controller 7110. The operation keys 7109 included in the remote controller 7110 can be used to control the channel and volume, and the image displayed on the display unit 7103 can be operated. Further, the remote controller 7110 may be provided with a display unit 7107 for displaying information output from the remote controller 7110.

The television device 7100 is configured to include a receiver, a modem, and the like. The receiver can receive general television broadcasts, and by connecting to a wired or wireless communication network via a modem, it can be unidirectional (sender to receiver) or bidirectional (sender and receiver). It is also possible to perform information communication between (or between recipients, etc.).

FIG. 6B shows a computer, which includes a main body 7201, a housing 7202, a display unit 7203, a keyboard 7204, an external connection port 7205, a pointing device 7206, and the like. A computer is manufactured by using a light emitting device for its display unit 7203.

FIG. 6C shows a portable game machine, which is composed of two housings, a housing 7301 and a housing 7302, and is connected by a connecting portion 7303 so as to be openable and closable. The display unit 7304 is incorporated in the housing 7301, and the display unit 7305 is incorporated in the housing 7302. In addition, the portable game machine shown in FIG. 6C also includes a speaker unit 7306, a recording medium insertion unit 7307, an LED lamp 7308, and input means (operation key 7309, connection terminal 7310, sensor 7311 (force, displacement, position). , Speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, voice, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, smell or infrared Includes a function to measure), microphone 7312), etc. Of course, the configuration of the portable game machine is not limited to the above, and it is sufficient that a light emitting device is used for at least both the display unit 7304 and the display unit 7305, or a configuration in which other auxiliary equipment is appropriately provided. can do. The portable game machine shown in FIG. 6 (C) has a function of reading a program or data recorded on a recording medium and displaying it on a display unit, and wirelessly communicates with another portable game machine to share information. Has a function. The functions of the portable game machine shown in FIG. 6 (C) are not limited to this, and can have various functions.

FIG. 6 (D) shows an example of a mobile phone. The mobile phone 7400 is equipped with an operation button 7403, an external connection port 7404, a speaker 7405, a microphone 7406, and the like, in addition to the display 7402 built into the housing 7401. The mobile phone 7400 is manufactured by using a light emitting device for the display unit 7402.

In the mobile phone 7400 shown in FIG. 6 (D), information can be input by touching the display unit 7402 with a finger or the like. In addition, operations such as making a phone call or composing an e-mail can be performed by touching the display unit 7402 with a finger or the like.

The screen of the display unit 7402 mainly has three modes. The first is a display mode that mainly displays an image, and the second is an input mode that mainly inputs information such as characters. The third is a display + input mode in which two modes, a display mode and an input mode, are mixed.

For example, when making a phone call or composing an e-mail, the display unit 7402 may be set to a character input mode mainly for inputting characters, and the characters displayed on the screen may be input. In this case, it is preferable to display the keyboard or the number button on most of the screen of the display unit 7402.

In addition, by providing a detection device having sensors such as a gyro and an acceleration sensor inside the mobile phone 7400, the orientation (vertical or horizontal) of the mobile phone 7400 can be determined and the screen display of the display unit 7402 can be determined. Can be switched automatically.

The screen mode can be switched by touching the display unit 7402 or by operating the operation button 7403 of the housing 7401. It is also possible to switch depending on the type of image displayed on the display unit 7402. For example, if the image signal displayed on the display unit is moving image data, the display mode is switched, and if the image signal is text data, the input mode is switched.

Also, in the input mode, the signal detected by the optical sensor of the display unit 7402 is detected, and if there is no input by the touch operation of the display unit 7402 for a certain period of time, the screen mode is switched from the input mode to the display mode. You may control it.

The display unit 7402 can also function as an image sensor. For example, the person can be authenticated by touching the display unit 7402 with a palm or a finger and photographing a palm print, a fingerprint, or the like. Further, if a backlight that emits near-infrared light or a sensing light source that emits near-infrared light is used for the display unit, finger veins, palmar veins, and the like can be imaged.

FIG. 6 (E) is a tabletop luminaire, which includes a lighting unit 7501, an umbrella 7502, a variable arm 7503, a support 7504, a stand 7505, and a power supply 7506. The tabletop lighting fixture is manufactured by using a light emitting device for the lighting unit 7501. The lighting fixtures include ceiling-fixed lighting fixtures and wall-mounted lighting fixtures.

FIG. 7 shows an example in which the light emitting device is used as an indoor lighting device 811. Since the light emitting device can have a large area, it can be used as a large area lighting device. In addition, it can also be used as a roll-type lighting device 812. As shown in FIG. 7, the desktop lighting fixture 813 described with reference to FIG. 6 (E) may be used in combination in the room equipped with the indoor lighting device 811.

As described above, an electronic device or a lighting fixture can be obtained by applying a light emitting device. The range of application of the light emitting device is extremely wide, and it can be applied to electronic devices in all fields.

The configuration shown in the present embodiment can be used by appropriately combining the configurations shown in the previous embodiment.

<p num="0192">In this example, a specific example of the composite material of one aspect of the present invention will be illustrated. The composite material of one aspect of the present invention comprises an organic compound having only a benzene ring and having 4 or more and 25 or less benzene rings, and an inorganic compound exhibiting electron acceptability for the organic compound. Including.</p><p num="0193">Table 1 shows the organic compounds used in the constituent examples 1 to 3 of this example and the HOMO level (eV) of the organic compounds. The HOMO level is a value measured by photoelectron spectroscopy. The structural formula of the organic compound is shown below.</p><p num="0194"><tables num="1"><img id="000006" he="26" wi="85" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></tables></p><p num="0195"><chemistry num="5"><img id="000007" he="77" wi="158" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></chemistry></p><p num="0196">The absorption spectrum of a toluene solution of 1,3,5-tri (biphenyl-3-yl) benzene (abbreviation: mBP3P) is shown in FIG. 8 (A), and the emission spectrum is shown in FIG. 8 (B). An ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, V550 type) was used for the measurement of the absorption spectrum. The solution was placed in a quartz cell for measurement. Regarding the absorption spectrum, the absorption spectrum obtained by subtracting the absorption spectrum measured by putting only toluene in the quartz cell is shown. In FIG. 8 (A), the horizontal axis represents the wavelength (nm) and the vertical axis represents the absorption intensity (arbitrary unit). In FIG. 8B, the horizontal axis represents the wavelength (nm) and the vertical axis represents the emission intensity (arbitrary unit). The peak emission wavelength of mBP3P was 349 nm (excitation wavelength 290 nm).</p><p num="0197">From FIG. 8 (A), it was found that the absorption spectrum of the toluene solution of mBP3P showed almost no absorption in the visible light region. Further, from FIG. 8B, it was found that mBP3P is suitable as a material for the hole transport layer in contact with the light emitting layer and a host material for the light emitting layer because the emission peak is on the short wavelength side.</p><p num="0198">In addition, as will be described later, the absorption spectrum of the mBP3P thin film also shows almost no absorption in the visible light region (see FIGS. 9 (A) and 9 (B)). Since almost no absorption was observed in the visible light region in both the solution and the thin film, it was found that the organic compound is suitable for both a single film and a mixed film with other organic compounds. From this, it was found that the organic compound can be suitably used for the composite material, the hole transport layer, and the light emitting layer of one aspect of the present invention.</p><p num="0199">Further, in the constituent examples 1 to 3, molybdenum oxide was used as the inorganic compound.</p><p num="0200">A method for producing a composite material according to one aspect of the present invention will be described.</p><p num="0201">(Configuration example 1) First, the glass substrate is fixed to the substrate holder in the vacuum vapor deposition apparatus. Then, mBP3P and molybdenum oxide (VI) were put into different resistance heating type evaporation sources, and 10^-4A film containing mBP3P and molybdenum oxide was formed by a co-evaporation method while the pressure was reduced to about Pa. At this time, co-deposition was performed so that the ratios of mBP3P and molybdenum oxide were 4: 2, 4: 1, and 4: 0.5 (= mBP3P: molybdenum oxide) in mass ratio. The film thickness was 50 nm.</p><p num="0202">FIG. 9 shows the results of measuring the absorption spectra of the composite film of mBP3P and molybdenum oxide (Structure Example 1) formed in this way. For comparison, the absorption spectrum of the mBP3P-only film (film thickness 50 nm) is also shown.</p><p num="0203">(Configuration example 2) First, the glass substrate is fixed to the substrate holder in the vacuum vapor deposition apparatus. Then, p-sexiphenyl (abbreviation: 6P) and molybdenum oxide (VI) are put into different resistance heating type evaporation sources, and 10^-4A film containing 6P and molybdenum oxide was formed by a co-evaporation method in a state where the pressure was reduced to about Pa. At this time, the ratios of 6P and molybdenum oxide were co-deposited so that the mass ratios were 4: 2, 4: 1, and 4: 0.5 (= 6P: molybdenum oxide). The film thickness was 50 nm.</p><p num="0204">The result of measuring the absorption spectrum of the composite film of 6P and molybdenum oxide (Structure Example 2) formed in this way is shown in FIG. For comparison, the absorption spectrum of a 6P-only film (film thickness 50 nm) is also shown.</p><p num="0205">(Configuration example 3) First, the glass substrate is fixed to the substrate holder in the vacuum vapor deposition apparatus. Then, 1,4-bis (triphenylsilyl) benzene (abbreviation: SiPSi) and molybdenum oxide (VI) are put into different resistance heating type evaporation sources, and 10^-4A film containing SiPSi and molybdenum oxide was formed by a co-evaporation method while the pressure was reduced to about Pa. At this time, the ratios of SiPSi and molybdenum oxide were co-deposited so that the mass ratios were 4: 2, 4: 1, and 4: 0.5 (= SiPSi: molybdenum oxide). The film thickness was 50 nm.</p><p num="0206">FIG. 11 shows the results of measuring the absorption spectra of the composite film of SiPSi and molybdenum oxide (Structure Example 3) formed in this way. For comparison, the absorption spectrum of the SiPSi-only film (film thickness 50 nm) is also shown.</p><p num="0207">In FIGS. 9 to 11, the horizontal axis represents wavelength (nm) and the vertical axis represents absorbance (no unit).</p><p num="0208">It was found that the composite material of one aspect of the present invention is a material having high translucency, with almost no remarkable absorption peak in the visible light region. Further, in the composite material of one aspect of the present invention, a remarkable absorption peak was hardly observed even in an infrared region (a region having a wavelength of 700 nm or more).</p><p num="0209">Further, the absorption spectrum of the composite material of one aspect of the present invention composed of the organic compound and molybdenum oxide has almost the same shape as the absorption spectrum of the organic compound, and a film having a high concentration of molybdenum oxide (specifically, In each configuration example, even in a film in which the ratio of the organic compound and molybdenum oxide was 4: 2 by mass), a remarkable absorption peak was hardly observed from the visible light region to the infrared region. This suggests that the composite material of one aspect of the present invention is less likely to absorb light due to charge transfer interaction.</p>

<p num="0210">In this embodiment, the light emitting device of one aspect of the present invention will be described with reference to FIG. 18 (A). The structural formula of the material used in this example is shown below. The structural formula of the material used in the previous embodiment will be omitted.</p><p num="0211"><chemistry num="6"><img id="000008" he="123" wi="158" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></chemistry></p><p num="0212">The manufacturing method of the light emitting element 1 of this example is shown below.</p><p num="0213">(Light emitting element 1) First, an indium tin oxide (ITSO) film containing silicon oxide was formed on the glass substrate 1100 by a sputtering method to form a first electrode 1101 that functions as an anode. The film thickness was 110 nm, and the electrode area was 2 mm × 2 mm.</p><p num="0214">As a pretreatment for forming a light emitting element on the substrate 1100, the surface of the substrate was washed with water, fired at 200 ° C. for 1 hour, and then UV ozone treatment was performed for 370 seconds.</p><p num="0215">Then 10^-4The substrate was introduced into a vacuum vapor deposition apparatus whose internal pressure was reduced to about Pa, and after vacuum firing at 170 ° C. for 30 minutes in a heating chamber inside the vacuum vapor deposition apparatus, the substrate 1100 was allowed to cool for about 30 minutes.</p><p num="0216">Next, the substrate 1100 on which the first electrode 1101 is formed is fixed to the substrate holder provided in the vacuum vapor deposition apparatus so that the surface on which the first electrode 1101 is formed faces downward, and 10^-4After reducing the pressure to about Pa, the hole injection layer 1111 was formed by co-depositing mBP3P and molybdenum oxide (VI) on the first electrode 1101. The film thickness was 50 nm, and the ratio of mBP3P to molybdenum oxide was adjusted to be 4: 2 (= mBP3P: molybdenum oxide) by mass ratio. The co-evaporation method is a vapor deposition method in which vapor deposition is performed simultaneously from a plurality of evaporation sources in one processing chamber.</p><p num="0217">Next, 9-phenyl-3- [4- (10-phenyl-9-anthryl) phenyl] -9H-carbazole (abbreviation: PCzPA) was formed on the hole injection layer 1111 so as to have a film thickness of 10 nm. The film was formed to form the hole transport layer 1112.</p><p num="0218">In addition, 9- [4- (N-carbazolyl)] phenyl-10-phenylanthracene (abbreviation: CzPA), and N, N'-bis (3-methylphenyl) -N, N'-bis [3- (9) -Phenyl-9H-fluorene-9-yl) phenyl] -pyrene-1,6-diamine (abbreviation: 1,6 mM FLPAPrn) was co-deposited to form a light emitting layer 1113 on the hole transport layer 1112. Here, the mass ratios of CzPA and 1,6 mMemFLPA Prn were adjusted to be 1: 0.04 (= CzPA: 1,6 mMMemFLPA Prn). The film thickness of the light emitting layer 1113 was set to 30 nm.</p><p num="0219">Next, CzPA was formed on the light emitting layer 1113 so as to have a film thickness of 10 nm to form the first electron transport layer 1114a.</p><p num="0220">Then, basophenanthroline (abbreviation: BPhen) was formed on the first electron transport layer 1114a so as to have a film thickness of 20 nm to form the second electron transport layer 1114b.</p><p num="0221">Further, lithium fluoride (LiF) was deposited on the second electron transport layer 1114b with a film thickness of 1 nm to form an electron injection layer 1115.</p><p num="0222">Finally, as the second electrode 1103 that functions as a cathode, aluminum was vapor-deposited to a film thickness of 200 nm to produce the light emitting device 1 of this embodiment.</p><p num="0223">In the above-mentioned vapor deposition process, the resistance heating method was used for all the vapor deposition.</p><p num="0224">Table 2 shows the element structure of the light emitting element 1 obtained as described above.</p><p num="0225"><tables num="2"><img id="000009" he="30" wi="137" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></tables></p><p num="0226">After performing the work of sealing the light emitting element 1 in a glove box having a nitrogen atmosphere so that the light emitting element is not exposed to the atmosphere, the operating characteristics of the light emitting element 1 were measured. The measurement was performed at room temperature (atmosphere maintained at 25 ° C).</p><p num="0227">The voltage-luminance characteristics of the light emitting element 1 are shown in FIG. In FIG. 12, the horizontal axis represents voltage (V) and the vertical axis represents brightness (cd / m).²). The brightness-current efficiency characteristics are shown in FIG. In FIG. 13, the horizontal axis is the brightness (cd / m).²), And the vertical axis represents the current efficiency (cd / A). In addition, the brightness of the light emitting element 1 is 1000 cd / m.²Table 3 shows the voltage (V), CIE chromaticity coordinates (x, y), current efficiency (cd / A), and external quantum efficiency (%) at.</p><p num="0228"><tables num="3"><img id="000010" he="25" wi="122" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></tables></p><p num="0229">1000 cd / m as shown in Table 3²The CIE chromaticity coordinates of the light emitting element 1 at the brightness of (x, y) = (0.14, 0.19). From this result, it was found that the light emitting element 1 obtained blue light emission derived from 1,6 mM FLPA Prn.</p><p num="0230">From FIGS. 12 and 13, it can be seen that the light emitting element 1 has a low drive voltage and a high luminous efficiency.</p><p num="0231">Next, the reliability test of the light emitting element 1 was performed. The results of the reliability test are shown in Fig. 14. In FIG. 14, the vertical axis shows the normalized luminance (%) when the initial luminance is 100%, and the horizontal axis shows the driving time (h) of the element.</p><p num="0232">Reliability test shows initial brightness of 5000 cd / m²The light emitting element of this embodiment was driven under the condition that the current density was constant.</p><p num="0233">From FIG. 14, the brightness of the light emitting element 1 after 170 hours maintained 65% of the initial brightness. It can be seen that the light emitting device 1 to which one aspect of the present invention is applied has a long life.</p><p num="0234">From the above results, it was shown that a device having high luminous efficiency can be realized by using the composite material of one aspect of the present invention for the hole injection layer of the light emitting device. Further, it has been shown that a light emitting device having a low driving voltage can be provided by using the composite material of one aspect of the present invention for the hole injection layer of the light emitting device. Further, it was shown that a long-life light emitting device can be produced by using the composite material of one aspect of the present invention for the hole injection layer.</p>

<p num="0235">In this embodiment, the light emitting device of one aspect of the present invention will be described with reference to FIG. 18 (B). The structural formula of the material used in this example is shown below. The structural formula of the material used in the previous embodiment will be omitted.</p><p num="0236"><chemistry num="7"><img id="000011" he="96" wi="158" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></chemistry></p><p num="0237">The manufacturing method of the light emitting elements 2 and 3 of this embodiment is shown below.</p><p num="0238">(Light emitting element 2) First, an ITSO film was formed on the glass substrate 1100 by a sputtering method to form a first electrode 1101 that functions as an anode. The film thickness was 110 nm, and the electrode area was 2 mm × 2 mm.</p><p num="0239">As a pretreatment for forming a light emitting element on the substrate 1100, the surface of the substrate was washed with water, fired at 200 ° C. for 1 hour, and then UV ozone treatment was performed for 370 seconds.</p><p num="0240">Then 10^-4The substrate was introduced into a vacuum vapor deposition apparatus whose internal pressure was reduced to about Pa, and after vacuum firing at 170 ° C. for 30 minutes in a heating chamber inside the vacuum vapor deposition apparatus, the substrate 1100 was allowed to cool for about 30 minutes.</p><p num="0241">Next, the substrate 1100 on which the first electrode 1101 is formed is fixed to the substrate holder provided in the vacuum vapor deposition apparatus so that the surface on which the first electrode 1101 is formed faces downward, and 10^-4After reducing the pressure to about Pa, the hole injection layer 1111 was formed by co-depositing mBP3P and molybdenum oxide (VI) on the first electrode 1101. The film thickness was 60 nm, and the ratio of mBP3P to molybdenum oxide was adjusted to be 4: 2 (= mBP3P: molybdenum oxide) by mass ratio.</p><p num="0242">Next, 1,3-bis (N-carbazolyl) benzene (abbreviation: mCP) was formed on the hole injection layer 1111 so as to have a film thickness of 20 nm to form the hole transport layer 1112.</p><p num="0243">In addition, mBP3P and Tris [3-methyl-1- (2-methylphenyl) -5-phenyl-1H-1,2,4-triazolat] iridium (III) (abbreviation: [Ir (Mptz1-mp))₃]) Was co-deposited to form a first light emitting layer 1113a on the hole transport layer 1112. Here, mBP3P and [Ir (Mptz1-mp)₃] Mass ratio is 1: 0.08 (= mBP3P: [Ir (Mptz1-mp)]₃]) Was adjusted to be. The film thickness of the first light emitting layer 1113a was set to 30 nm.</p><p num="0244">Then, 2- [3- (dibenzothiophen-4-yl) phenyl] -1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), and [Ir (Mptz1-mp)₃] Was co-deposited to form a second light emitting layer 1113b on the first light emitting layer 1113a. Here, mDBTBIm-II and [Ir (Mptz1-mp)₃] Mass ratio is 1: 0.08 (= mDBTBIm-II: [Ir (Mptz1-mp)]₃]) Was adjusted to be. The film thickness of the second light emitting layer 1113b was set to 10 nm.</p><p num="0245">Next, BPhen was formed on the second light emitting layer 1113b so as to have a film thickness of 15 nm to form an electron transport layer 1114.</p><p num="0246">Further, LiF was deposited on the electron transport layer 1114 with a film thickness of 1 nm to form an electron injection layer 1115.</p><p num="0247">Finally, as the second electrode 1103 that functions as a cathode, aluminum was vapor-deposited so as to have a film thickness of 200 nm to produce the light emitting device 2 of this embodiment.</p><p num="0248">(Light emitting element 3) The hole transport layer 1112 of the light emitting device 3 was formed by forming a film of mBP3P so as to have a film thickness of 20 nm. Except for the hole transport layer 1112, it was produced in the same manner as the light emitting device 2.</p><p num="0249">In the above-mentioned vapor deposition process, the resistance heating method was used for all the vapor deposition.</p><p num="0250">Table 4 shows the element structures of the light emitting elements 2 and 3 obtained as described above.</p><p num="0251"><tables num="4"><img id="000012" he="41" wi="137" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></tables></p><p num="0252">After performing the work of sealing the light emitting elements 2 and 3 in a glove box having a nitrogen atmosphere so that the light emitting elements were not exposed to the atmosphere, the operating characteristics of the light emitting elements 2 and 3 were measured. The measurement was performed at room temperature (atmosphere maintained at 25 ° C).</p><p num="0253">The voltage-luminance characteristics of the light emitting elements 2 and 3 are shown in FIG. In FIG. 15, the horizontal axis represents voltage (V) and the vertical axis represents brightness (cd / m).²). The brightness-current efficiency characteristics are shown in FIG. In FIG. 16, the horizontal axis is the brightness (cd / m).²), And the vertical axis represents the current efficiency (cd / A). In addition, the brightness of the light emitting elements 2 and 3 is 500 cd / m.²Table 5 shows the voltage (V), CIE chromaticity coordinates (x, y), current efficiency (cd / A), and external quantum efficiency (%) in the vicinity.</p><p num="0254"><tables num="5"><img id="000013" he="36" wi="122" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></tables></p><p num="0255">500cd / m²The CIE chromaticity coordinates of the light emitting element 2 at near brightness are (x, y) = (0.18,0.29), and the CIE chromaticity coordinates of the light emitting element 3 are (x, y) = (0.18,0.30). there were. From this result, the light emitting elements 2 and 3 are [Ir (Mptz1-mp).₃] It was found that a blue luminescence derived from was obtained.</p><p num="0256">From FIGS. 15 and 16, it can be seen that the light emitting elements 2 and 3 have low drive voltages and high luminous efficiencies, respectively.</p><p num="0257">Next, the reliability test of the light emitting elements 2 and 3 was performed. The results of the reliability test are shown in FIG. In FIG. 17, the vertical axis shows the normalized luminance (%) when the initial luminance is 100%, and the horizontal axis shows the driving time (h) of the element.</p><p num="0258">Reliability test shows initial brightness of 300 cd / m²The light emitting element of this embodiment was driven under the condition that the current density was constant.</p><p num="0259">From FIG. 17, it was 81 hours that the light emitting element 2 maintained 50% of the initial brightness, and 47 hours that the light emitting element 3 maintained 50% of the initial brightness.</p><p num="0260">Since the phosphorescent substance exhibiting blue color or the host material used together with the phosphorescent substance has a high T1 level, the bandgap is wide and the HOMO level tends to be low. Therefore, it is difficult to inject holes into the luminescent substance, and the drive voltage tends to increase and the life tends to decrease. The organic compound (here, mBP3P) used in the composite material of one aspect of the present invention is a material having a low HOMO level. By using the composite material of one aspect of the present invention for the hole injection layer, holes can be satisfactorily injected into the hole transport layer. In particular, by using mBP3P as an organic compound contained in a hole injection layer (a layer using a composite material according to one aspect of the present invention), a material for a hole transport layer, and a host material for a light emitting layer, up to the light emitting layer. Holes can be injected well. The composite material of one aspect of the present invention can be suitably used for a phosphorescent light emitting device that exhibits a blue color as shown in this example. By using the composite material of one aspect of the present invention, it is possible to realize a light emitting device in which an increase in driving voltage and a decrease in life are suppressed.</p>

<p num="0261">In this embodiment, the light emitting device of one aspect of the present invention will be described with reference to FIG. 18 (A). The structural formula of the material used in this example is shown below. The structural formula of the material used in the previous embodiment will be omitted.</p><p num="0262"><chemistry num="8"><img id="000014" he="46" wi="158" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></chemistry></p><p num="0263">The manufacturing method of the light emitting elements 4 and 5 of this embodiment is shown below.</p><p num="0264">(Light emitting element 4) First, an ITSO film was formed on the glass substrate 1100 by a sputtering method to form a first electrode 1101 that functions as an anode. The film thickness was 110 nm, and the electrode area was 2 mm × 2 mm.</p><p num="0265">As a pretreatment for forming a light emitting element on the substrate 1100, the surface of the substrate was washed with water, fired at 200 ° C. for 1 hour, and then UV ozone treatment was performed for 370 seconds.</p><p num="0266">Then 10^-4The substrate was introduced into a vacuum vapor deposition apparatus whose internal pressure was reduced to about Pa, and after vacuum firing at 170 ° C. for 30 minutes in a heating chamber inside the vacuum vapor deposition apparatus, the substrate 1100 was allowed to cool for about 30 minutes.</p><p num="0267">Next, the substrate 1100 on which the first electrode 1101 is formed is fixed to the substrate holder provided in the vacuum vapor deposition apparatus so that the surface on which the first electrode 1101 is formed faces downward, and 10^-4After reducing the pressure to about Pa, the hole injection layer 1111 was formed by co-depositing SiPSi and molybdenum oxide (VI) on the first electrode 1101. The film thickness was 50 nm, and the ratio of SiPSi to molybdenum oxide was adjusted to be 4: 2 (= SiPSi: molybdenum oxide) by mass ratio.</p><p num="0268">Next, PCzPA was formed on the hole injection layer 1111 so as to have a film thickness of 20 nm to form the hole transport layer 1112.</p><p num="0269">Further, CzPA and 1,6 mM FLPAPrn were co-deposited to form a light emitting layer 1113 on the hole transport layer 1112. Here, the mass ratio of CzPA and 1,6 mMMemFLPA Prn was adjusted to be 1: 0.04 (= CzPA: 1,6 mMMemFLPA Prn). The film thickness of the light emitting layer 1113 was set to 30 nm.</p><p num="0270">Next, CzPA was formed on the light emitting layer 1113 so as to have a film thickness of 10 nm to form the first electron transport layer 1114a.</p><p num="0271">Then, BPhen was formed on the first electron transport layer 1114a so as to have a film thickness of 15 nm to form the second electron transport layer 1114b.</p><p num="0272">Further, LiF was deposited on the second electron transport layer 1114b with a film thickness of 1 nm to form an electron injection layer 1115.</p><p num="0273">Finally, as the second electrode 1103 that functions as a cathode, aluminum was vapor-deposited to a film thickness of 200 nm to produce the light emitting device 4 of this embodiment.</p><p num="0274">(Light emitting element 5) The hole injection layer 1111 of the light emitting device 5 was formed by co-depositing 4,4'-bis (triphenylsilyl) biphenyl (abbreviation: SiBiSi) and molybdenum oxide (VI). The film thickness was 50 nm, and the ratio of SiBiSi to molybdenum oxide was adjusted to be 4: 2 (= SiBiSi: molybdenum oxide) by mass ratio. Except for the hole injection layer 1111, it was produced in the same manner as the light emitting device 4.</p><p num="0275">In the above-mentioned vapor deposition process, the resistance heating method was used for all the vapor deposition.</p><p num="0276">Table 6 shows the element structures of the light emitting elements 4 and 5 obtained as described above.</p><p num="0277"><tables num="6"><img id="000015" he="43" wi="135" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></tables></p><p num="0278">After performing the work of sealing the light emitting elements 4 and 5 in a glove box having a nitrogen atmosphere so that the light emitting elements were not exposed to the atmosphere, the operating characteristics of the light emitting elements 4 and 5 were measured. The measurement was performed at room temperature (atmosphere maintained at 25 ° C).</p><p num="0279">The voltage-luminance characteristics of the light emitting elements 4 and 5 are shown in FIG. In FIG. 19, the horizontal axis represents voltage (V) and the vertical axis represents brightness (cd / m).²). The brightness-current efficiency characteristics are shown in FIG. In FIG. 20, the horizontal axis is the brightness (cd / m).²), And the vertical axis represents the current efficiency (cd / A). In addition, the brightness of the light emitting elements 4 and 5 is 1000 cd / m.²Table 7 shows the voltage (V), CIE chromaticity coordinates (x, y), current efficiency (cd / A), and external quantum efficiency (%) at.</p><p num="0280"><tables num="7"><img id="000016" he="37" wi="122" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></tables></p><p num="0281">1000cd / m²The CIE chromaticity coordinates of the light emitting element 4 at the brightness of are (x, y) = (0.14,0.17), and the CIE chromaticity coordinates of the light emitting element 5 are (x, y) = (0.14,0.16). It was. From this result, it was found that the light emitting elements 4 and 5 could emit blue light derived from 1,6 mM FLPAPrn.</p><p num="0282">From FIGS. 19 and 20, it can be seen that the light emitting elements 4 and 5 have low drive voltages and high luminous efficiencies, respectively. Further, it can be seen that the driving voltage of the light emitting element 5 using SiBiSi having a biphenylene group is particularly low.</p><p num="0283">From the above results, it was shown that a device having high luminous efficiency can be realized by using the composite material of one aspect of the present invention for the hole injection layer of the light emitting device. Further, it has been shown that a light emitting device having a low driving voltage can be provided by using the composite material of one aspect of the present invention for the hole injection layer of the light emitting device.</p>

<p num="0284">In this example, 1,3,5-tris [(3,5-diphenyl) phenyl] benzene (abbreviation: mTP3P), which is an organic compound that can be used in the composite material of one aspect of the present invention, will be described. The structural formula of mTP3P is shown below.</p><p num="0285"><chemistry num="9"><img id="000017" he="65" wi="158" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></chemistry></p><p num="0286">The absorption spectrum of the toluene solution of mTP3P is shown in FIG. 21 (A), and the emission spectrum is shown in FIG. 21 (B). The absorption spectrum of the mTP3P thin film is shown in FIG. 22 (A), and the emission spectrum is shown in FIG. 22 (B). An ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, V550 type) was used for the measurement of the absorption spectrum. The solution was placed in a quartz cell for measurement. Regarding the absorption spectrum, the absorption spectrum obtained by subtracting the absorption spectrum measured by putting only toluene in a quartz cell was shown for the solution, and the absorption spectrum obtained by subtracting the absorption spectrum of the quartz substrate was shown for the thin film. In FIGS. 21 (A) and 22 (A), the horizontal axis represents the wavelength (nm) and the vertical axis represents the absorption intensity (arbitrary unit). In FIGS. 21 (B) and 22 (B), the horizontal axis represents the wavelength (nm) and the vertical axis represents the emission intensity (arbitrary unit). In the case of the toluene solution, the peak emission wavelengths were 295 nm, 304 nm, and 347 nm (excitation wavelength 385 nm). In the case of the thin film, the peak emission wavelength was 356 nm (excitation wavelength 271 nm).</p><p num="0287">As can be seen from FIGS. 21 (A) and 22 (A), the absorption spectrum of the toluene solution of mTP3P and the absorption spectrum of the thin film show almost no absorption in the visible light region. Since almost no absorption was observed in the visible light region in both the solution and the thin film, it was found that the organic compound is suitable for both a single film and a mixed film with other organic compounds. Further, as can be seen from FIGS. 21 (B) and 22 (B), the emission peak of mTP3P is on the short wavelength side. From the above, mTP3P can be suitably used for the composite material of one aspect of the present invention, the material of the hole transport layer, or the light emitting layer (particularly the host material).</p><p num="0288">mTP3P has a high glass transition point (Tg) of 132 ° C and a stable film quality. From this, mTP3P can be suitably used for the composite material of one aspect of the present invention.</p>

<p num="0289">In this example, bis [3,5-di (biphenyl-3-yl) phenyl] diphenylsilane (abbreviation: mBP22PSi), which is an organic compound that can be used in the composite material of one aspect of the present invention, will be described. The structural formula of mBP22PSi is shown below.</p><p num="0290"><chemistry num="10"><img id="000018" he="67" wi="158" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></chemistry></p><p num="0291">[Synthesis method of mBP22PSi] The synthesis scheme of mBP22PSi is shown below.</p><p num="0292"><chemistry num="11"><img id="000019" he="68" wi="158" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></chemistry></p><p num="0293">Diphenyl-di (3,5-dibromobenzene) silane 1.4 g (2.2 mmol), 3-biphenylboronic acid 1.9 g (9.7 mmol), palladium (II) acetate 110 mg (0.5 mmol), tri (ortho) in a 100 ml three-necked flask. -Trill) phosphine 290 mg (1.0 mmol) was added and replaced with nitrogen. Toluene (20 mL), ethanol (2 mL), and 2.0 M potassium carbonate aqueous solution (10 mL) (potassium carbonate 2.7 g) were added, and the mixture was degassed by stirring under reduced pressure. The mixture was stirred at 85 ° C for 14 hours under a nitrogen stream. Subsequently, 0.4 g (2.2 mmol) of 3-biphenylboronic acid, 290 mg (1.0 mmol) of tri (ortho-tolyl) phosphine, and 110 mg (0.5 mmol) of palladium acetate were added, and the mixture was further stirred at 85 ° C. under a nitrogen stream for 13 hours. After stirring, the mixture was filtered through Celite (Wako Pure Chemical Industries, Ltd., Catalog No .: 531-16855). Water was added to the filtrate and extracted with toluene, the obtained organic layer was washed with saturated brine, and magnesium sulfate was added to adsorb water. The obtained mixture was naturally filtered, and the yellow oil obtained by concentration was purified by silica gel column chromatography (hexane: toluene = 3: 1) to obtain a white solid. Methanol was added to the white solid and the suspension obtained by irradiating with ultrasonic waves was suction-filtered to obtain 1.14 g of the target white solid (yield 56%).</p><p num="0294">It was confirmed by nuclear magnetic resonance spectroscopy (NMR) that this compound was the target substance, mBP22PSi.</p><p num="0295">Of the obtained substance¹The 1 H NMR data is shown below.¹1 H NMR (CDCl₃, 300MHz): δ (ppm) = 7.30-7.59 (m, 38H), 7.74-7.79 (m, 8H), 7.95 (d, J = 1.5Hz, 4H), 7.97 (d, J = 1.5Hz, 2H) ..</p><p num="0296">Also,¹The 1 H NMR chart is shown in FIG. Note that FIG. 23 (B) is an enlarged chart showing the range of 6.00 ppm to 10.00 ppm in FIG. 23 (A).</p><p num="0297">The absorption spectrum of the toluene solution of mBP22PSi is shown in FIG. 24 (A), and the emission spectrum is shown in FIG. 24 (B). The absorption spectrum of the thin film of mBP22PSi is shown in FIG. 25 (A), and the emission spectrum is shown in FIG. 25 (B). An ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, V550 type) was used for the measurement of the absorption spectrum. The solution was placed in a quartz cell for measurement. Regarding the absorption spectrum, the absorption spectrum obtained by subtracting the absorption spectrum measured by putting only toluene in a quartz cell was shown for the solution, and the absorption spectrum obtained by subtracting the absorption spectrum of the quartz substrate was shown for the thin film. In FIGS. 24 (A) and 25 (A), the horizontal axis represents the wavelength (nm) and the vertical axis represents the absorption intensity (arbitrary unit). In FIGS. 24 (B) and 25 (B), the horizontal axis represents the wavelength (nm) and the vertical axis represents the emission intensity (arbitrary unit). In the case of the toluene solution, the peak emission wavelength was 336 nm (excitation wavelength 287 nm). In the case of the thin film, the peak emission wavelengths were 338 nm, 342 nm, and 348 nm (excitation wavelength 256 nm).</p><p num="0298">As can be seen from FIGS. 24 (A) and 25 (A), the absorption spectrum of the toluene solution of mBP22PSi and the absorption spectrum of the thin film show almost no absorption in the visible light region. Since almost no absorption was observed in the visible light region in both the solution and the thin film, it was found that the organic compound is suitable for both a single film and a mixed film with other organic compounds. Further, as can be seen from FIGS. 24 (B) and 25 (B), the emission peak of mBP22PSi is on the short wavelength side. From the results of this example, it was found that mBP22PSi can be suitably used for the composite material of one aspect of the present invention, the material of the hole transport layer, or the light emitting layer (particularly the host material).</p>

<p num="0299">In this embodiment, the light emitting device of one aspect of the present invention will be described with reference to FIG. 18 (B). Since the material used in this example is the material used in the previous example, the structural formula is omitted.</p><p num="0300">The manufacturing method of the light emitting element 6 of this example is shown below.</p><p num="0301">(Light emitting element 6) First, an ITSO film was formed on the glass substrate 1100 by a sputtering method to form a first electrode 1101 that functions as an anode. The film thickness was 110 nm, and the electrode area was 2 mm × 2 mm.</p><p num="0302">As a pretreatment for forming a light emitting element on the substrate 1100, the surface of the substrate was washed with water, fired at 200 ° C. for 1 hour, and then UV ozone treatment was performed for 370 seconds.</p><p num="0303">Then 10^-4The substrate was introduced into a vacuum vapor deposition apparatus whose internal pressure was reduced to about Pa, and after vacuum firing at 170 ° C. for 30 minutes in a heating chamber inside the vacuum vapor deposition apparatus, the substrate 1100 was allowed to cool for about 30 minutes.</p><p num="0304">Next, the substrate 1100 on which the first electrode 1101 is formed is fixed to the substrate holder provided in the vacuum vapor deposition apparatus so that the surface on which the first electrode 1101 is formed faces downward, and 10^-4After reducing the pressure to about Pa, the hole injection layer 1111 was formed by co-depositing mBP22PSi and molybdenum oxide (VI) on the first electrode 1101. The film thickness was 60 nm, and the ratio of mBP22PSi to molybdenum oxide was adjusted to be 4: 2 (= mBP22PSi: molybdenum oxide) by mass ratio.</p><p num="0305">Next, mBP22PSi was formed on the hole injection layer 1111 so as to have a film thickness of 20 nm to form the hole transport layer 1112.</p><p num="0306">In addition, mBP22PSi and [Ir (Mptz1-mp)₃] Was co-deposited to form a first light emitting layer 1113a on the hole transport layer 1112. Here, mBP22PSi, and [Ir (Mptz1-mp)₃] Mass ratio is 1: 0.06 (= mBP22PSi: [Ir (Mptz1-mp)]₃]) Was adjusted to be. The film thickness of the first light emitting layer 1113a was set to 30 nm.</p><p num="0307">And mDBTBIm-II, and [Ir (Mptz1-mp)₃] Was co-deposited to form a second light emitting layer 1113b on the first light emitting layer 1113a. Here, mDBTBIm-II, and [Ir (Mptz1-mp)₃] Mass ratio is 1: 0.06 (= mDBTBIm-II: [Ir (Mptz1-mp)]₃]) Was adjusted to be. The film thickness of the second light emitting layer 1113b was set to 10 nm.</p><p num="0308">Next, BPhen was formed on the second light emitting layer 1113b so as to have a film thickness of 15 nm to form an electron transport layer 1114.</p><p num="0309">Further, LiF was deposited on the electron transport layer 1114 with a film thickness of 1 nm to form an electron injection layer 1115.</p><p num="0310">Finally, as the second electrode 1103 that functions as a cathode, aluminum was vapor-deposited to a film thickness of 200 nm to produce the light emitting device 6 of this embodiment.</p><p num="0311">In the above-mentioned vapor deposition process, the resistance heating method was used for all the vapor deposition.</p><p num="0312">Table 8 shows the element structure of the light emitting element 6 obtained as described above.</p><p num="0313"><tables num="8"><img id="000020" he="28" wi="138" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></tables></p><p num="0314">The light emitting element 6 was sealed in a glove box having a nitrogen atmosphere so that the light emitting element was not exposed to the atmosphere, and then the operating characteristics of the light emitting element 6 were measured. The measurement was performed at room temperature (atmosphere maintained at 25 ° C).</p><p num="0315">The luminance-current efficiency characteristics of the light emitting element 6 are shown in FIG. In FIG. 26, the horizontal axis is the brightness (cd / m).²), And the vertical axis represents the current efficiency (cd / A). In addition, the luminance-chromaticity coordinate characteristics are shown in FIG. In FIG. 27, the horizontal axis is the brightness (cd / m).²), And the vertical axis represents the chromaticity coordinates (x-coordinate or y-coordinate) . The brightness-external quantum efficiency characteristics are shown in FIG. In FIG. 28, the horizontal axis is the brightness (cd / m).²), And the vertical axis represents the external quantum efficiency (%). The emission spectrum of the light emitting element 6 is shown in FIG. In FIG. 29, the horizontal axis represents the wavelength (nm) and the vertical axis represents the emission intensity (arbitrary unit). In addition, the brightness of the light emitting element 6 is 800 cd / m.²Table 9 shows the voltage (V), CIE chromaticity coordinates (x, y), current efficiency (cd / A), and external quantum efficiency (%) at.</p><p num="0316"><tables num="9"><img id="000021" he="25" wi="121" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></tables></p><p num="0317">800cd / m²The CIE chromaticity coordinates of the light emitting element 6 at the brightness of (x, y) = (0.18, 0.29). From this result, the light emitting element 6 is [Ir (Mptz1-mp).₃] It was found that a blue luminescence derived from was obtained.</p><p num="0318">It was found that mBP22PSi has a high T1 level and can be used as a host material for dispersing a luminescent material (guest material) that exhibits luminescence (phosphorescence or fluorescence) in the visible light region.</p><p num="0319">From FIGS. 26 and 28, it can be seen that the light emitting element 6 has high luminous efficiency.</p><p num="0320">Further, from FIG. 27, the color change of the light emitting element 6 was hardly observed from low brightness to high brightness. From this, it can be said that the light emitting element 6 is an element having a good carrier balance.</p><p num="0321">Next, the reliability test of the light emitting element 6 was performed. The results of the reliability test are shown in Fig. 30. In FIG. 30, the vertical axis shows the normalized luminance (%) when the initial luminance is 100%, and the horizontal axis shows the driving time (h) of the element.</p><p num="0322">Reliability test shows initial brightness of 300 cd / m²The light emitting element of this embodiment was driven under the condition that the current density was constant.</p><p num="0323">From FIG. 30, it was 72 hours that the light emitting element 6 maintained 50% of the initial brightness.</p><p num="0324">Since the phosphorescent substance exhibiting blue color or the host material used together with the phosphorescent substance has a high T1 level, the bandgap is wide and the HOMO level tends to be low. Therefore, it is difficult to inject holes into the luminescent substance, and the drive voltage tends to increase and the life tends to decrease. The organic compound (here, mBP22PSi) used in the composite material of one aspect of the present invention is a material having a low HOMO level. By using the composite material of one aspect of the present invention for the hole injection layer, holes can be satisfactorily injected into the hole transport layer. In particular, by using mBP22PSi as an organic compound contained in a hole injection layer (a layer using a composite material according to one aspect of the present invention), a material for a hole transport layer, and a host material for a light emitting layer, a first method can be used. Holes can be satisfactorily injected from the electrode to the light emitting layer. Moreover, since the same material can be used for a plurality of layers, the synthesis cost can be suppressed. The composite material of one aspect of the present invention can be suitably used for a phosphorescent light emitting device that exhibits a blue color as shown in this example. By using the composite material of one aspect of the present invention, it is possible to realize a light emitting device in which an increase in driving voltage and a decrease in life are suppressed.</p>

<p num="0325">In this embodiment, the light emitting device of one aspect of the present invention will be described with reference to FIG. 18 (B). The structural formula of the material used in this example is shown below. The structural formula of the material used in the previous embodiment will be omitted.</p><p num="0326"><chemistry num="12"><img id="000022" he="37" wi="158" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></chemistry></p><p num="0327">The manufacturing method of the light emitting element 7 to the light emitting element 9 of this example is shown below.</p><p num="0328">(Light emitting element 7) The light emitting device 7 was manufactured by applying the same materials, methods, and conditions as those of the light emitting device 6 of Example 7 except for the hole transport layer 1112.</p><p num="0329">The hole transport layer 1112 of the light emitting element 7 was formed by forming a film of mCP so as to have a film thickness of 20 nm.</p><p num="0330">(Light emitting element 8) The light emitting element 8 was manufactured by applying the same materials, methods, and conditions as those of the light emitting element 7 except for the first light emitting layer 1113a.</p><p num="0331">The first light emitting layer 1113a of the light emitting element 8 includes mBP22PSi, 9-phenyl-9H-3- (9-phenyl-9H-carbazole-3-yl) carbazole (abbreviation: PCCP), and [Ir (Mptz1-mp).₃] Was formed by co-depositing. Here, mBP22PSi, PCCP, and [Ir (Mptz1-mp)₃] Mass ratio is 1: 0.25: 0.06 (= mBP22PSi: PCCP: [Ir (Mptz1-mp)]₃]) Was adjusted to be. The film thickness of the first light emitting layer 1113a was set to 30 nm.</p><p num="0332">(Light emitting element 9) The light emitting device 9 was manufactured by applying the same materials, methods, and conditions as those of the light emitting device 8 except for the electron transport layer 1114.</p><p num="0333">The electron transport layer 1114 of the light emitting device 9 was formed by forming a film of mDBTBIm-II so as to have a film thickness of 15 nm.</p><p num="0334">Table 10 shows the element structures of the light emitting elements 7 to 9 obtained as described above.</p><p num="0335"><tables num="10"><img id="000023" he="59" wi="138" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></tables></p><p num="0336">After performing the work of sealing these light emitting elements in a glove box having a nitrogen atmosphere so that the light emitting elements were not exposed to the atmosphere, the operating characteristics of these light emitting elements were measured. The measurement was performed at room temperature (atmosphere maintained at 25 ° C).</p><p num="0337">The brightness-current efficiency characteristics of the light emitting elements 7 to 9 are shown in FIG. In FIG. 31, the horizontal axis is the brightness (cd / m).²), And the vertical axis represents the current efficiency (cd / A). The luminance-chromaticity coordinate characteristics are shown in FIG. In FIG. 32, the horizontal axis is the brightness (cd / m).²), And the vertical axis represents the chromaticity coordinates (x-coordinate or y-coordinate). The brightness-external quantum efficiency characteristics are shown in FIG. In FIG. 33, the horizontal axis is the brightness (cd / m).²), And the vertical axis represents the external quantum efficiency (%). Further, the emission spectra of the light emitting elements 7 to 9 are shown in FIG. 34. In FIG. 34, the horizontal axis represents the wavelength (nm) and the vertical axis represents the emission intensity (arbitrary unit). In addition, the brightness of the light emitting elements 7 to 9 is 700 cd / m.²Table 11 shows the voltage (V), CIE chromaticity coordinates (x, y), current efficiency (cd / A), and external quantum efficiency (%) in the vicinity.</p><p num="0338"><tables num="11"><img id="000024" he="47" wi="122" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></tables></p><p num="0339">700cd / m²The CIE chromaticity coordinates of the light emitting element 7 at near brightness are (x, y) = (0.19,0.30), and the CIE chromaticity coordinates of the light emitting element 8 are (x, y) = (0.17,0.27). Yes, the CIE chromaticity coordinates of the light emitting element 9 were (x, y) = (0.18, 0.28). From this result, the light emitting element 7 to the light emitting element 9 are [Ir (Mptz1-mp).₃] It was found that a blue luminescence derived from was obtained.</p><p num="0340">From FIGS. 31 and 33, it can be seen that the light emitting elements 7 to 9 have high luminous efficiency.</p><p num="0341">Further, from FIG. 32, the color change of the light emitting element 7 to the light emitting element 9 was hardly observed from low brightness to high brightness. From this, it can be said that the light emitting element 7 to the light emitting element 9 are elements having a good carrier balance.</p><p num="0342">Further, from Table 11, it can be seen that the light emitting element 8 and the light emitting element 9 have a lower drive voltage than the light emitting element 7. It is considered that this is because holes are efficiently injected into the first light emitting layer by containing PCCP having high hole transporting property in the first light emitting layer of the light emitting element 8 and the light emitting element 9. ..</p><p num="0343">By including the organic compound (here, mBP22PSi) used in the hole injection layer in the first light emitting layer, holes can be satisfactorily injected from the first electrode to the first light emitting layer. In addition, the luminescent material (guest material, here [Ir (Mptz1-mp))₃]) A device with a low drive voltage is realized by including an auxiliary dopant material (PCCP in this case), which has a HOMO level relatively close to the HOMO level and has high hole transportability, in the first light emitting layer. can do. Specifically, the difference between the HOMO level of the guest material and the HOMO level of the auxiliary dopant material is preferably 0.2 eV or less.</p><p num="0344">Further, from Table 11, it can be seen that the light emitting element 7 has higher current efficiency than the light emitting element 8 and the light emitting element 9. This is because the T1 level of mBP22PSi, which is an organic compound of one aspect of the present invention, is high, and the excitation energy generated in the first light emitting layer is efficiently [Ir (Mptz1-mp).₃] It is thought that it is because it has moved to. Since mBP22PSi, which is an organic compound of one aspect of the present invention, has a high (small absolute value) LUMO level and a low (large absolute value) HOMO level, carriers injected into the first light emitting layer ( (Hole and electron) are trapped in the layer and efficiently [Ir (Mptz1-mp)₃], It is considered that the carrier loss was suppressed and the recombination probability was increased.</p><p num="0345">Next, the reliability test of the light emitting element 7 to the light emitting element 9 was performed. The results of the reliability test are shown in Fig. 35. In FIG. 35, the vertical axis shows the normalized luminance (%) when the initial luminance is 100%, and the horizontal axis shows the driving time (h) of the element.</p><p num="0346">Reliability test shows initial brightness of 300 cd / m²The light emitting element of this embodiment was driven under the condition that the current density was constant.</p><p num="0347">From FIG. 35, the light emitting element 7 maintained 50% of the initial brightness for 93 hours, the light emitting element 8 maintained 50% of the initial brightness for 44 hours, and the light emitting element 9 maintained 50% of the initial brightness. It was 110 hours that maintained 50% of the initial brightness.</p><p num="0348">Since the phosphorescent substance exhibiting blue color or the host material used together with the phosphorescent substance has a high T1 level, the bandgap is wide and the HOMO level tends to be low. Therefore, it is difficult to inject holes into the luminescent substance, and the drive voltage tends to increase and the life tends to decrease. The organic compound (here, mBP22PSi) used in the composite material of one aspect of the present invention is a material having a low HOMO level. By using the composite material of one aspect of the present invention for the hole injection layer, holes can be satisfactorily injected into the hole transport layer. In particular, by using mBP22PSi as a host material for the hole injection layer (organic compound contained in the composite material), the hole transport layer, and the light emitting layer, holes can be satisfactorily injected into the light emitting layer. The composite material of one aspect of the present invention can be used for a phosphorescent light emitting device that exhibits a blue color as shown in this example. By using the composite material of one aspect of the present invention, it is possible to realize a light emitting device in which an increase in driving voltage and a decrease in life are suppressed.</p>

<p num="0349">In this embodiment, the light emitting device of one aspect of the present invention will be described with reference to FIG. 18 (A). The structural formula of the material used in this example is shown below. The structural formula of the material used in the previous embodiment will be omitted.</p><p num="0350"><chemistry num="13"><img id="000025" he="98" wi="158" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></chemistry></p><p num="0351">The manufacturing method of the light emitting element 10 of this example is shown below.</p><p num="0352">(Light emitting element 10) First, an ITSO film was formed on the glass substrate 1100 by a sputtering method to form a first electrode 1101 that functions as an anode. The film thickness was 110 nm, and the electrode area was 2 mm × 2 mm.</p><p num="0353">As a pretreatment for forming a light emitting element on the substrate 1100, the surface of the substrate was washed with water, fired at 200 ° C. for 1 hour, and then UV ozone treatment was performed for 370 seconds.</p><p num="0354">Then 10^-4The substrate was introduced into a vacuum vapor deposition apparatus whose internal pressure was reduced to about Pa, and after vacuum firing at 170 ° C. for 30 minutes in a heating chamber inside the vacuum vapor deposition apparatus, the substrate 1100 was allowed to cool for about 30 minutes.</p><p num="0355">Next, the substrate 1100 on which the first electrode 1101 is formed is fixed to the substrate holder provided in the vacuum vapor deposition apparatus so that the surface on which the first electrode 1101 is formed faces downward, and 10^-4After depressurizing to about Pa, the hole injection layer 1111 is co-deposited with 4,4'-di (N-carbazolyl) biphenyl (abbreviation: CBP) and molybdenum oxide (VI) on the first electrode 1101. Was formed. The film thickness was 60 nm, and the ratio of CBP to molybdenum oxide was adjusted to be 4: 2 (= CBP: molybdenum oxide) by mass ratio.</p><p num="0356">Next, 4-phenyl-4'-(9-phenylfluorene-9-yl) triphenylamine (abbreviation: BPAFLP) was formed on the hole injection layer 1111 so as to have a film thickness of 20 nm. A hole transport layer 1112 was formed.</p><p num="0357">In addition, mBP22PSi and Tris (2-phenylpyridinato-N, C)^2’) Iridium (III) (abbreviation: [Ir (ppy)₃]) Was co-deposited to form a light emitting layer 1113 on the hole transport layer 1112. Here, mBP22PSi, and [Ir (ppy)₃] Mass ratio is 1: 0.06 (= mBP22PSi: [Ir (ppy))₃]) Was adjusted to be. The film thickness of the light emitting layer 1113 was set to 40 nm.</p><p num="0358">Next, mDBTBIm-II was formed on the light emitting layer 1113 so as to have a film thickness of 15 nm to form the first electron transport layer 1114a.</p><p num="0359">Then, BPhen was formed on the first electron transport layer 1114a so as to have a film thickness of 20 nm to form the second electron transport layer 1114b.</p><p num="0360">Further, LiF was deposited on the second electron transport layer 1114b with a film thickness of 1 nm to form an electron injection layer 1115.</p><p num="0361">Finally, as the second electrode 1103 that functions as a cathode, aluminum was vapor-deposited so as to have a film thickness of 200 nm to produce the light emitting device 10 of this embodiment.</p><p num="0362">In the above-mentioned vapor deposition process, the resistance heating method was used for all the vapor deposition.</p><p num="0363">Table 12 shows the element structure of the light emitting element 10 obtained as described above.</p><p num="0364"><tables num="12"><img id="000026" he="30" wi="138" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></tables></p><p num="0365">After performing the work of sealing the light emitting element 10 in a glove box having a nitrogen atmosphere so that the light emitting element is not exposed to the atmosphere, the operating characteristics of the light emitting element 10 were measured. The measurement was performed at room temperature (atmosphere maintained at 25 ° C).</p><p num="0366">The luminance-current efficiency characteristics of the light emitting element 10 are shown in FIG. In FIG. 36, the horizontal axis is the brightness (cd / m).²), And the vertical axis represents the current efficiency (cd / A). The luminance-chromaticity coordinate characteristics are shown in FIG. 37. In FIG. 37, the horizontal axis is the brightness (cd / m).²), And the vertical axis represents the chromaticity coordinates (x-coordinate or y-coordinate). The brightness-external quantum efficiency characteristics are shown in FIG. 38. In FIG. 38, the horizontal axis is the brightness (cd / m).²), And the vertical axis represents the external quantum efficiency (%). The emission spectrum of the light emitting element 10 is shown in FIG. 39. In FIG. 39, the horizontal axis represents the wavelength (nm) and the vertical axis represents the emission intensity (arbitrary unit). In addition, the brightness of the light emitting element 10 is 1000 cd / m.²Table 13 shows the voltage (V), CIE chromaticity coordinates (x, y), current efficiency (cd / A), and external quantum efficiency (%) at.</p><p num="0367"><tables num="13"><img id="000027" he="25" wi="122" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></tables></p><p num="0368">1000 cd / m as shown in Table 13²The CIE chromaticity coordinates of the light emitting element 10 at the brightness of (x, y) = (0.32,0.62). From this result, the light emitting element 10 is [Ir (ppy).₃] It was found that a green luminescence derived from was obtained.</p><p num="0369">It was found that mBP22PSi has a high T1 level and can be used as a host material for dispersing a phosphorescent material having a wavelength longer than green and a light emitting material (guest material) exhibiting fluorescence in the visible light region.</p><p num="0370">From FIGS. 36 and 38, it can be seen that the light emitting element 10 has high luminous efficiency.</p><p num="0371">Further, from FIG. 37, the light emitting element 10 showed almost no color change from low brightness to high brightness. From this, it can be said that the light emitting element 10 is an element having a good carrier balance.</p><p num="0372">Next, the reliability test of the light emitting element 10 was performed. The results of the reliability test are shown in Fig. 40. In FIG. 40, the vertical axis shows the normalized luminance (%) when the initial luminance is 100%, and the horizontal axis shows the driving time (h) of the element.</p><p num="0373">Reliability test shows initial brightness of 1000 cd / m²The light emitting element 10 was driven under the condition that the current density was constant.</p><p num="0374">From FIG. 40, the brightness of the light emitting element 10 after 250 hours was 84% of the initial brightness.</p><p num="0375">From the above results, it was shown that mBP22PSi, which is an organic compound according to one aspect of the present invention, can be suitably used as a host material for a light emitting layer.</p><p num="0376">(Reference example 1) Tris [3-methyl-1- (2-methylphenyl) -5-phenyl-1H-1,2,4-triazolat] iridium (III) (abbreviation: [Ir (Mptz1-mp)) used in the above examples.₃] Is shown as an example of synthesizing.</p><p num="0377">[Step 1: Synthesis of N- (1-ethoxyethylidene) benzamide] First, ethyl acetate hydrochloride 15.5 g, toluene 150 mL, triethylamine (Et)₃N) 31.9 g was placed in a 500 mL three-necked flask and stirred at room temperature for 10 minutes. A mixed solution of 17.7 g of benzoyl chloride and 30 mL of toluene was added dropwise to this mixture from a 50 mL dropping funnel, and the mixture was stirred at room temperature for 24 hours. After a lapse of time, the reaction mixture was suction filtered and the solid was washed with toluene. The resulting filtrate was concentrated to give N- (1-ethoxyethylidene) benzamide (red oil, 82% yield). The synthesis scheme of step 1 is shown below.</p><p num="0378"><chemistry num="14"><img id="000028" he="34" wi="158" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></chemistry></p><p num="0379">[Step 2: Synthesis of 3-Methyl-1- (2-Methylphenyl) -5-Phenyl-1H-1,2,4-Triazole (abbreviation: HMptz1-mp)] Next, o-trilhydrazine hydrochloride 8.68 g, carbon tetrachloride 100 mL, triethylamine (Et)₃N) 35 mL was placed in a 300 mL eggplant flask and stirred at room temperature for 1 hour. After a lapse of a predetermined time, 8.72 g of N- (1-ethoxyethylidene) benzamide obtained in step 1 above was added to this mixture, and the mixture was stirred at room temperature for 24 hours. After a lapse of a predetermined time, water was added to the reaction mixture, and the organic substance was extracted with chloroform from the aqueous layer. The extract solution and the organic layer were washed with saturated brine, and anhydrous magnesium sulfate was added and dried. The resulting mixture was naturally filtered and the filtrate was concentrated to give an oil. The obtained oil was purified by silica gel column chromatography. Dichloromethane was used as the developing solvent. The resulting fraction was concentrated to give 3-methyl-1- (2-methylphenyl) -5-phenyl-1H-1,2,4-triazole (abbreviation: HMptz1-mp) (orange oil, Yield 84%). The synthesis scheme of step 2 is shown below.</p><p num="0380"><chemistry num="15"><img id="000029" he="47" wi="158" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></chemistry></p><p num="0381">[Step 3; Tris [3-Methyl-1- (2-Methylphenyl) -5-Phenyl-1H-1,2,4-Triazolate] Iridium (III) (abbreviation: [Ir (Mptz1-mp))₃]) Synthesis] Next, 2.71 g of the ligand HMptz1-mp2.71 g and 1.06 g of tris (acetylacetonato) iridium (III) obtained in step 2 above were placed in a reaction vessel equipped with a three-way cock. This reaction vessel was replaced with argon and heated at 250 ° C. for 48 hours to react. The reaction mixture was dissolved in dichloromethane and purified by silica gel column chromatography. As the developing solvent, first, dichloromethane was used, and then a mixed solvent of dichloromethane: ethyl acetate = 10: 1 (volume ratio) was used. The obtained fraction was concentrated to give a solid. The solid was washed with ethyl acetate and then recrystallized from a mixed solvent of dichloromethane and ethyl acetate to form an organometallic complex [Ir (Mptz1-mp).₃] Was obtained (yellow powder, yield 35%). The synthesis scheme of step 3 is shown below.</p><p num="0382"><chemistry num="16"><img id="000030" he="71" wi="158" file="JP6034603B2_D0001.tif" img-format="tif" img-content="drawing" /></chemistry></p><p num="0383">Nuclear magnetic resonance spectroscopy of the yellow powder obtained in step 3 above (¹The analysis results by 1 H NMR) are shown below. From this result, [Ir (Mptz1-mp)₃] Was obtained.</p><p num="0384">Of the obtained substance¹The 1 H NMR data is shown below.¹1 NMR.δ (CDCl₃): 1.94-2.21 (m, 18H), 6.47-6.76 (m, 12H), 7.29-7.52 (m, 12H).</p>

100 boards 101 First electrode 102 EL layer 108 Second electrode 401 Source side drive circuit 402 Pixel part 403 Gate side drive circuit 404 Encapsulation board 405 Sealing material 407 space 408 Route wiring 409 FPC (Flexible Print Circuit) 410 element board 411 TFT for switching 412 TFT for current control 413 First electrode 414 insulation 416 EL layer 417 Second electrode 418 Luminescent element 423 n-channel TFT 424 p channel type TFT 501 board 502 First electrode 503 Second electrode 504 EL layer 505 insulation layer 506 bulkhead layer 701 hole injection layer 702 hole transport layer 703 Luminescent layer 704 Electron transport layer 705 Electron injection layer 706 Electron injection buffer layer 707 Electronic relay layer 708 composite layer 800 1st EL layer 801 Second EL layer 802 EL layer 803 Charge generation layer 811 Lighting device 812 Lighting equipment 813 Desktop lighting fixture 900 Luminous device 901 First board 902 Second board 903 1st terminal 904 2nd terminal 908 Luminescent element 909 Insulation layer 910 Auxiliary wiring 911 desiccant 912 Sealing material 913a Light extraction structure 913b Light extraction structure 1100 board 1101 first electrode 1103 second electrode 1111 Hole injection layer 1112 Hole transport layer 1113 Light emitting layer 1113a First light emitting layer 1113b Second light emitting layer 1114 Electron transport layer 1114a First electron transport layer 1114b Second electron transport layer 1115 Electron injection layer 7100 television device 7101 chassis 7103 Display 7105 stand 7107 Display 7109 Operation keys 7110 Remote control device 7201 Body 7202 chassis 7203 Display 7204 keyboard 7205 External connection port 7206 Pointing device 7301 housing 7302 housing 7303 Connection 7304 Display 7305 Display 7306 Speaker section 7307 Recording medium insertion part 7308 LED lamp 7309 Operation keys 7310 Connection terminal 7311 sensor 7312 Microphone 7400 mobile phone 7401 chassis 7402 Display 7403 Operation button 7404 External connection port 7405 speaker 7406 microphone 7501 Lighting unit 7502 Umbrella 7503 Variable arm 7504 prop 7505 units 7506 power supply