Transparent front electrode for use in photovoltaic device and method of making same

Front electrode for Use in Photovoltaic Device and Method of Making Same

Background of the invention

Certain embodiments of this invention relate to a photovoltaic device including an electrode such as a front electrode/contact. In some representative embodiments of this invention, the front electrode comprises or is made of a transparent conductive coating (TCC) plurality of layers, and is positioned on the surface of a front glass substrate opposite a patterned surface. surface of the substrate.

In some exemplary embodiments, the patterned (i.e., etched) surface of the front transparent glass substrate faces incoming light, where the TCC is provided on the opposite side of the substrate facing the semiconductor layer of the photovoltaic (PV) device. In other words, the permeable glass substrate has a typical first surface and a TCC of a front electrode on its second surface. The typical first or front surface of the glass substrate reduces incident solar flux reflection losses and increases absorption of photon(s) in the semiconductor film through scattering, refraction, and difffusion. TCC can enhance transmission in selected PV regions active in the visible and near IR spectrum, while rejecting and/or blocking unwanted IR thermal energy from certain other regions of the spectrum.

In some exemplary embodiments, the front electrode of the photovoltaic (PV) device includes a multilayer coating (or TCC) material comprising at least one substantially infrared (IR) reflective and conductive metal layer made of or comprising silver, gold, or the like, and the packaging material may include at least one transparent conductive oxide (TCO) layer (e.g., made of or including tin oxide, zinc oxide, or similar). In some representative embodiments, the multilayer front electrode coating material is designed to achieve one or more of the following characteristic properties: (a) Low sheet resistance (Rs) thus increasing conductivity and improving the overall output power of a photovoltaic module output power photovoltaic module output power; (b) Increased reflection of infrared (IR) and thus reduce the operating temperature of the photovoltaic module in order to increase the output power of the module; (c) Reducing the reflection and/or increasing the transmission of light in the region ranging from 450-700 nm, and/or 450-600 nm, and this leads to Increase the output power of the photovoltaic module; (d) Reducing the overall thickness of the front electrode packing material, which can reduce manufacturing costs and/or time; And/or (e) improving or expanding the processing window when forming the TCO layer(s) due to the reduced effect of the conductivity of the TCO layers on the overall electrical properties of the module given the presence of a mainly metallic layer(s) that reflects infrared (IR) radiation. Highly conductive.

Photovoltaic devices are known in the art (for example, see US Patents 6,784,361, 6,288,325, 6,613,603, and 6,123,824, the disclosures of which are incorporated herein by reference). Photovoltaic devices made of amorphous silicon, for example, include a front electrode or contact.

Typically, the front electrode is made of a transparent conductive oxide (TCO) such as zinc oxide or tin oxide formed on a substrate such as a glass substrate. In many cases, a single-layer front electrode is formed using a chemical pyrolysis method in which chemical pyrolysis-producing raw materials are sprayed onto a glass substrate at about 400 to 600°C. Typical TCO layers of tin oxide doped with fluorine that decompose heat and are used as front electrodes can be about 400 nm thick, providing a sheet resistance (Rs) of about 15 ohms/square. To obtain a large output power, it is desirable to have a front electrode that has low sheet resistance and good ohmic contact with the top layer of the cell, allowing maximum solar energy in certain desirable ranges to penetrate the absorbing semiconductor film.

Unfortunately, photovoltaic devices (e.g., solar cells) that include conventional TCO front electrodes suffer from the following problems.

First, the fluorine-doped pyrolytic TCO layer of about 400 nm thick used as the full front electrode has a sheet resistance (Rs) of about 15 ohms/square, which is large for a full front electrode. It is desirable to have a lower plate resistance (and thus better conductivity) for the front electrode of a photovoltaic device. A lower sheet resistance can be achieved by increasing the thickness of such a TCO layer, but this will cause less light to pass through the TCO layer, reducing the output power of the photovoltaic (PV) device.

Second, conventional TCO front electrodes such as tin oxide allow a fairly large amount of infrared (IR) radiation to pass through it, allowing it to reach the semiconductor or absorbent layer(s) of the photovoltaic device. Photovoltaic (PV) device. These infrared rays cause heat that increases the operating temperature of the photovoltaic device and thus reduces its output power.

Third, conventional TCO front electrodes such as pyrolytic tin oxide tend to reflect a fairly large amount of light in the region of about 450-700 nm so that at least about 80% of the useful solar energy reaches the semiconductor layer. semiconductor absorbing layer; This fairly high reflection of visible light is a waste of energy and results in reduced photovoltaic module output power. Because of the absorption of the TCO layer and the reflections of light that occur between the TCO layer (n is about 1.8 to 2 at a wavelength of 550 nm) and the thin film semiconductor (n is about 3.0 to 4.5), and between the TCO layer and the glass substrate ( n is about 1.5), the TCO-coated glass at the front of the photovoltaic (PV) device typically allows less than 80% of the useful solar energy that hits the device to reach the semiconductor membrane, which converts Light into electrical energy.

Fourth, the large total thickness (e.g., 400 nm) of the front electrode in the case of a 400 nm tin oxide TCO layer causes increased manufacturing costs.

Fifth, the processing window for forming a TCO layer of zinc oxide or tin oxide to make a front electrode is small and significant. In this regard, even small changes in the curing window can negatively affect the conductivity of the TCO layer. When the TCO layer is a single conductive layer of the front electrode, such negative effects can be severely harmful.

Based on this, it can be recognized that there is a need in the field for an improved front electrode for a photovoltaic device that can solve or address one or more of the five problems mentioned above.

General description of the invention

In some representative embodiments of this invention, the front electrode of a photovoltaic device includes a multi-plurality of layers transparent conductive coating (TCC) material, which is placed on the surface of a front glass substrate opposite. Patterned surface of the substrate. In some exemplary embodiments, the patterned (i.e., etched) surface of the front transparent glass substrate faces incoming light, wherein the TCC is provided on the opposite side of the substrate facing the semiconductor layer of the photovoltaic (PV) device. . The typical first or front surface of the glass substrate reduces incident solar flux reflection losses and increases absorption of photon(s) in the semiconductor film through scattering, refraction, and difffusion.

In some representative embodiments of this invention, the front electrode of a photovoltaic device includes a multilayer coating comprising a substantially conductive metallic IR reflecting layer (e.g., a silver-based layer, or gold, or the like), and optionally on at least one transparent conductive oxide (TCO) layer (e.g., made of or comprising a material such as tin oxide, zinc oxide, or etc.). In certain representative cases, the plurality of layers of the front electrode coating material may comprise a plurality of TCO layers and/or a plurality of primarily conductive IR reflective metal layers, alternately arranged in order to serve to reduce visible light reflections , increased conductivity, increased ability to reflect IR rays, etc.

In some representative embodiments of this invention, a plurality of layers laminated material for a front electrode can be designed to achieve one or more of the following characteristic properties: (a) Low sheet resistance (Rs) thus increasing conductivity and improving the overall output power of a photovoltaic module output power; (b) Increase infrared (IR) reflectance and thus reduce the operating temperature of the photovoltaic module in order to increase the output power of the module; (c) reduce reflection and increase light transmission in the region(s) of approximately 450-700 nm, and/or 450-600 nm, which results in increased output power of the photovoltaic module; (Dr) Reducing the overall thickness of the front electrode packing material, which can reduce manufacturing costs and/or time; And/or (e) improving or expanding the processing window when forming the TCO layer(s) due to the reduced effect of the conductivity of the TCO layers on the overall electrical properties of the module given the presence of a metallic layer(s) that primarily reflects infrared rays. IR is highly conductive.

In some representative embodiments of this invention, a photovoltaic device is provided comprising: front glass substrate; an active semiconductor membrane; A substantially permeable front electrode located between at least the front glass substrate and the semiconductor membrane; Wherein the highly permeable front electrode, as it moves away from the front glass substrate toward the semiconducting film, includes at least one highly permeable layer which may be conductive or non-conductive, a primarily infrared reflective metallic layer ( IR) includes silver and/or gold, At least one transparent conductive oxide (TCO) film is placed between the IR reflective layer and the semiconducting film; Whereas the front electrode is provided on the inner surface of the front glass substrate facing the semiconductor film, the textured surface of the front glass substrate facing the light reduces incidental solar flux reflection losses and increases the absorption of photons in the semiconductor film.

In some representative embodiments of this invention, a photovoltaic device is provided comprising:

glass substrate; Semiconductor film; and a substantially permeable front electrode located at least between the substrate and the fabricated semiconductor film; Whereas, the substantially permeable electrode, as it moves away from the glass substrate toward the semiconducting film, comprises a substantially conductive metal layer comprising silver, and a transparent conductive oxide (TCO) film located at least between The layer containing silver and the semiconductor membrane.

Brief explanation of the drawings

Figure 1: A cross-section view of a representative photovoltaic device according to a representative embodiment of this invention.

Figure 2: It is a curve showing the refractive index (n) versus wavelength (nm). It shows the refractive index (n) of glass, a TCO film, a thin film of silver, and hydrogenated silicon (in a non-metallic phase). (microcrystalline or amorphous, micro- or poly-crystal line phase).

Figure 3: A curve showing the percentage of transmittance (T%) versus wavelength (nm), which shows the transmittance spectra in a thin film of hydrogenated silicon for a photovoltaic device to compare examples of this invention with a comparative example (reference TCO); This shows that the examples of this invention (Examples 1, 2, and 3) have increased transmittance in the wavelength range of approximately 450-700 nm and thus have helped increase the output power of the typical photovoltaic module, compared to the comparative example (reference TCO).

Figure 4: is a curve showing the percentage of reflectance (R%) versus wavelength (nm), showing the reflectance spectra from a thin film of hydrogenated silicon for a photovoltaic device in order to compare examples of this invention (Examples 1, 2, and 3 indicated in Figure 3) versus a comparative example (reference TCO indicated in Figure 3); This shows that the representative embodiment of this invention has increased reflectivity in the IR range, and this has resulted in a reduction in the operating temperature of the photovoltaic module in order to Increased output power of the module, compared to the comparative example. Whereas the same examples 1-3 and the comparative example (reference TCO) have been referred to in Figures 3 and 4, the same specific curves used in Figure 3 are also used in Figure 4.

Figure 5: A cross-section view of a photovoltaic (PV) device according to Example No. 1 of this invention.

Figure 6: A cross-section view of a photovoltaic device according to Example No. 2 of this invention.

Figure 7: A cross-section view of a photovoltaic device according to Example No. 3 of this invention.

Figure 8: A cross-section view of a photovoltaic device according to another representative embodiment of this invention.

Figure 9: A cross-section view of a photovoltaic device according to another representative embodiment of this invention.

Figure 10: A cross-section view of a photovoltaic device according to another representative embodiment of this invention.

Figure 11: A cross-section view of a photovoltaic device according to another representative embodiment of this invention.

Figure 12: A measured emission (T) and reflectance (R) spectrum (% of first surface 1a) versus wavelength (nm), showing the results of Example 4 (with a 10 ohm/sq Ag-based TCC coating material for a front glass substrate front glass substrate has a textured surface).

Figure 13: A graph of transmission ratio versus wavelength (nm), showing the results according to Example 4 (compared to the comparative example).

Figure 14: A graph of transmission percentage (T%) versus wavelength (nm) showing the transmission spectrum in a Si cell for a photovoltaic (PV) device, showing the results of Example 5 of this invention having a composite front surface to the front glass substrate.

Figure 15: is a graph of transmission percentage (T%) versus wavelength (nm) showing the transition spectrum in a CdS/CdTe cell for a photovoltaic device, comparing Example 4 of this invention (having a composite front surface to the front glass substrate) against comparative examples; This shows that Example 4 of this invention achieves increased transmission at a wavelength of about 500-700 nm and thus a typical voltaic output power, compared to the comparative example without the etched front surface (dotted line .

Detailed description

Referring now more specifically to figures in which similar reference numbers indicate similar parts/layers in multiple views.

Photovoltaic devices, such as solar cells, convert solar radiation into usable electrical energy. Typically, energy conversion occurs as a result of the photovoltaic effect. Solar radiation (e.g., sunlight) incident on a photovoltaic device is absorbed by an active region of a semiconductor material (e.g., a semiconductor film containing one or more semiconductor layers, e.g. Layers made of silicon, and sometimes the semiconductor layer is called the absorbent layer or absorbent membrane), by generating an electron-hole pair in the active region. Electrons and holes can be separated by an electric field at a junction in a photovoltaic (PV) device. The separation of electrons and holes by the junction generates an electric current and an electric voltage. In some exemplary embodiments, electrons flow toward the region of the semiconductor material that has n-type conductivity, and holes flow toward the region of the semiconductor material that has p-conductivity. Current can flow through an external circuit that connects the n-type region to the p-type region while light continues to generate electron-hole pairs in the photovoltaic (PV) device.

In some exemplary embodiments, photovoltaic devices made of single junction amorphous silicon (single Si junction) comprise three semiconductor layers. Specifically, a p-type layer, an n-type layer, and an i-type layer, which is the original layer. An amorphous silicon film (which can include one or more layers such as p-, n-, and i-type layers) can be hydrogenated amorphous silicon in some cases, but it can also be It may comprise hydrogenated amorphous silicon carbon, hydrogenated amorphous silicon germanium, or the like, in some representative embodiments of this invention. For example, but not limited to, when a photon of light is absorbed in the layer, it leads to an increase in the unit of electrical current (an electron-hole pair). The p and n layers, which contain charged dopant ions, create an electric field through the i layer that pulls the electrical charge out of the i layer and sends it to an optional external circuit where it can provide power to the electrical components. It should be noted that while some representative embodiments of this invention have been directed towards amorphous-silicon based photovoltaic devices, this invention is not limited to them and can be used with other types of photovoltaic devices and in some cases including: But not limited to devices incorporating other types of semiconductor materials, single or double thin-film solar cells, CdS and/or CdTe photovoltaic devices (including CdS/CdTe), and Photovoltaics made from polysilicon and/or microcrystalline Si, and the like.

In certain embodiments of this invention, the front electrode of the PV device comprises or is made of a transparent conductive coating (TCC) plurality of layers, and is positioned on the surface of a front glass substrate opposite corresponding to a typical substrate surface patterned surface of the substrate. In some exemplary embodiments, the patterned (i.e., etched) surface of the front transparent glass substrate faces incoming light, wherein the TCC is provided on the opposite side of the substrate facing the semiconductor layer of the photovoltaic (PV) device. . The typical first or front surface of the glass substrate reduces incident solar flux reflection losses and increases absorption of photon(s) in the semiconductor film through scattering, refraction, and difffusion. TCC can enhance transmission in selected PV regions active in the visible and near IR spectrum, while rejecting and/or blocking unwanted IR thermal energy from certain other regions of the spectrum. In some representative embodiments of this invention, the surface of the front glass substrate on which the front electrode or TCC is placed can be flat or substantially flat (atypical), while in alternative representative embodiments, it can also be typical.

Figure 1 is a cross-section view of a photovoltaic device according to a representative embodiment of this invention. The photovoltaic device includes a transparent front glass substrate (1) (another suitable substrate material may also be used in place of glass in some cases), optional dielectric layer(s) (2), and an electrode a multilayer front electrode (3), and an active semiconductor film (5) made of or including one or more semiconductor layers (such as tandem layer stacks such as pin, pn, pinpin, or the like), And a back electrode/contact back electrode/contact (7) which may be made of TCO or metal, an optional encapsulant (9) or adhesive of a material such as ethyl vinyl acetate (EVA) or similar, and an optional top layer superstrate (11) of a material such as glass. Of course, another layer(s), not explained, can be added to the device. The front glass substrate (1) and/or rear superstate (11) may be made of soda-lime-silica based glass, in some embodiments of this invention; They can have a low iron content and/or an anti-reflective coating applied to them to optimize transmittance in some representative cases. While the substrate(s) (1, 11) may be made of glass in some representative embodiments of this invention, other materials such as quartz, plastic, or the like may be used to fabricate the substrate(s) (1) and/or (11) instead Of glass. Furthermore, the superstate (11) is optional in some cases. Glass (1) and/or (11) may or may not be heat-tempered and/or heat-formed, in some representative embodiments of this invention. Furthermore, it must be understood that the word "on" as used herein covers both a layer that is placed directly or indirectly on an object, while other layers may be located between it and the object.

The dielectric layer(s) (2) can be of any substantially permeable material such as metal oxide and/or nitride, which can have a refractive index of about 1.5 to 2.5, preferably From about 1.6 to 2.5, the best from about 1.6 to 2.2, the best from about 1.6 to 2, and the most favorable from about 1.6 to 1.8. However, in some cases, the insulating layer (2) can have a refractive index (n) of about 2.3 to 2.5. Examples of materials from which the insulating layer is made (2) include:

silicon oxide, silicon nitride, silicon oxynitride, zinc oxide, tin oxide, titanium oxide (e.g., TiO2), aluminum oxynitride, aluminum oxide, or mixtures of the foregoing. The insulating layer(s) (2) acts as a protective layer in some embodiments of this invention, in order to prevent substances such as sodium from migrating outward from the glass substrate (1) and reaching the IR and/or semi-infrared reflective layer(s). Mosul. In addition to this, the insulating layer (2) is a material with a refractive index (n) in the range described above, in order to reduce visible light reflection and thus increase transmission of visible light. (For example, light with a wavelength of about 450-700 nm and/or 450-600 nm) passes through the coating and into the semiconductor (5), leading to an increase in the output power of the photovoltaic module. Stereotyping.

Continuing with reference to Figure 1, the multilayer front electrode (3) in the representative model shown in Figure 1, which is provided for representational purposes only and not for limitation purposes, includes, starting at the glass substrate (1) and moving outward , on a transparent conductive oxide (TCO) layer or a first dielectric layer (3a), a first layer that is primarily metallic and conductive to infrared IR (3b), a second TCO layer (3c), and a second, primarily metallic layer. IR reflective and permeable (3D), third TCO layer (3E), and optional protective layer (3F). Optionally, layer 3a can be a dielectric layer instead of the TCO layer in some cases and act as a core layer for layer 3b. This multilayer film (3) forms the front electrode in some representative embodiments of this invention. Naturally, some layers of electrode (3) may be removed in some alternative representative embodiments of this invention (e.g., one or more layers 3a, 3c, 3d, and/or 3e may be removed), as Additional layers can also be provided in the multilayer electrode (3). The front electrode (3) may extend continuously across all or a significant portion of the glass substrate (1), or alternatively may be patterned to have a desired design (e.g., strips), in various exemplary embodiments thereof. Invention. Each of the layers/membranes (1-3) is substantially permeable in some representative embodiments of this invention.

The first and second conductors 3b and 3d can be made of both essentially metal layers that reflect IR rays, or they can include any suitable IR-reflecting material such as silver, gold, or the like. These materials reflect large amounts of IR rays, and this leads to a reduction in the amount of IR that reaches the semiconductor membrane (5). Since IR increases the temperature of the device, reducing the amount of IR radiation reaching the semiconductor film 5 is beneficial in that it reduces the operating temperature of the photovoltaic module resulting in an increase in the output power of the photovoltaic module. Furthermore, the highly conductive nature of such mainly metallic layers (3b) and/or (3d) enables an increase in the overall electrode conductivity (3). In some representative embodiments of this invention, the multilayer electrode (3) has a sheet resistance of less than or equal to about 12 ohms/square, better of less than or equal to about 9 ohms/square, and even better of less than or equal to about 6 ohms/square. Square. Again, increasing conductivity (which also means reducing plate resistance) increases the total output power of the photovoltaic module, by reducing losses due to resistance in the side direction in which the current is to be controlled at the cell cutting edge. It should be noted that the primarily metallic IR-reflecting and conductive first and second layers (3b) and (3d) (as well as the other layers of electrode 3) are thin enough to be highly permeable to visible light. In some representative embodiments of this invention, the thickness of the first and second essentially metallic IR-reflecting and conducting layers (3b) and (3d) ranges from about 3 to 12 nm, preferably from about 5 to 10 nm, and more preferably from about 5 nm. to 8 nm. In embodiments where neither layer 3b or 3d is used, the thickness of the remaining primarily metallic IR-reflecting and conducting layer can range from about 3 to 18 nm, preferably from about 5 to 12 nm, and most preferably from about 3 to 18 nm. About 6 to 11 nm in some representative embodiments of this invention. These thicknesses (plural thickness) are desirable in that they allow the 3B and/or 3D layers to reflect a large amount of IR radiation, while at the same time being highly permeable to the visible radiation that is allowed to reach the semiconductor 5 for the photovoltaic device. (PV) device converts it into electrical energy. The highly conductive IR-reflecting layers (3b) and (3d) contribute to the overall conductivity of electrode (3) to a much greater extent than the TCO layers. This allows expanding the processing window(s) of TCO layer(s) that have limited window area to achieve both high conductivity and permeability.

The first, second, and third TCO layers 3a, 3c, and 3e, respectively, may be of any suitable TCO material including, but not limited to, conductive forms of:

zinc oxide, zinc aluminum oxide, tin oxide, tin antimony oxide, zinc tin oxide, indium tin oxide, indium zinc oxide

(It can be treated with silver), or something similar. These layers typically have equivalent sub-quantities in order to make them conductive according to what is known in the field. For example, these layers are made of material(s) that give them a resistance of no more than about 10 ohm cm (preferably not more than 1 ohm cm, and most preferably no more than about 20 ohm cm). One or more of these layers may be treated by doping with other materials such as fluorine, aluminum, antimony, or the like, in some representative cases, as long as they remain highly conductive to visible light. In some representative embodiments of this invention, the TCO layers (3c) and/or 3e are thicker than the layer (3a) (e.g., at least about 5 nm thicker, at least about 10 more preferably, at least about 20 or 30 nm thicker at least). In some representative embodiments of this invention, the thickness of the TCO layer (3a) ranges from about 3 to 80 nm, preferably from about 10 nm, having a representative thickness of about 10 nm. The optional layer (3a) is provided primarily as a core layer for layer (3b) and/or for anti-reflection purposes, and its conductivity is not as important as that of layers 3b 3e (therefore, layer 3a can be an insulator instead of a TCO layer in some embodiments representation). In some representative embodiments of this invention, the thickness of the TCO layer (3c) ranges from about 20 to about 150 nm, preferably from about 40 to 120 nm, having a representative thickness of about 74 75 nm. In some representative embodiments of this invention, the TCO (3e) layer has a thickness ranging from about 20 to 180 nm, preferably from about 40 to 130 nm, having a representative thickness of about 94 or 115 nm. In some representative embodiments of this invention, a portion of the layer (3e) has a thickness of, for example, about 1-25 nanometers or 5-25 nanometers, at the junction between layers (3e) and (5) and may be replaced by a membrane. Low conductivity with a large refractive index (n) (3F) such as titanium oxide in order to enhance light transmittance as well as reduce the back diffusion of generated electric charge carriers; In this way the performance can be improved better.

In some exemplary embodiments, the textured surface 1a of the front glass substrate is designed

Transparent glass substrate 1 (i.e. engraved and/or patterned). In this application, the use of the word "patterned" covers etched surfaces, and the use of the word "etched" covers patterned surfaces. The textured surface 1a of the front glass substrate 1 can include a prismatic surface, a rough finishing surface, or the like in various embodiments of this invention. The outer surface 1a of the front glass substrate 1 may have peaks and valleys defined therein by curved segments interconnected with the peaks and valleys (for example, see Fig. 1). The main surface of the substrate 1 may be etched (e.g., by high-frequency etching using a high-frequency etching method or the like), or typically by roller(s) or the like during glass manufacturing to form Composite (and/or modular) surface 1a. In some representative embodiments, the patterned (e.g., etched) surface 1a of the front transmitting glass substrate faces incoming light (see sun in the figures), wherein TCC3 is provided on the corresponding surface 1b of the substrate facing the semiconductor membrane 5 of the device Photovoltaic (PV) device. The typical first or front surface of the glass substrate 1 reduces incident solar flux reflection losses and increases absorption of photon(s) in the semiconductor film 5 through scattering, refraction, and/or difffusion. Solar flux transmission can also be developed in the photovoltaic semiconductor 5 using a patterned/etched surface 1a of the front glass substrate 1 in combination with an Ag-based TCC3 as shown in Figures 1 and 5-11. The patterned and/or embossed surface 1 results in an effective low index coating due to the introduction of void(s), acting as an antireflection coating. Compared to a smooth front surface, a patterned and/or patterned surface 1 offers the following ideal advantages: (a) low reflection from the first surface 1a, especially at skewed incident angles, due to trapped light and thus increased solar flux in solar cells, and (b) Increased optical path of light in semiconductor 5 resulting in increased photovoltaic current. This can be applied to models of Figures 1 and 5-11 in certain cases.

In some representative embodiments of this invention, the average surface roughness on surface 1a of the front glass substrate ranges from about 0.1 µm to 1 mm, most preferably from about 0.5 to 20 µm, most preferably from about 0.1 to 10 µm, most preferably from about 2 8 micrometer. A larger value of surface roughness can lead to more fouling collection on the front substrate 1, while a lower value of surface roughness 1a will insufficiently increase transmission. This surface roughness of 1a can be applied to any model discussed herein. Providing this surface roughness at surface 1a is advantageous because it can avoid the need for a separate AR shell on the glass front substrate 1 in some representative embodiments of this invention.

In some exemplary embodiments, the inner or second surface 1b of the front glass substrate 1 is flat or substantially flat. In other words, surface 1b is not patterned or etched. In these embodiments, as shown in the figures, the front electrode 3 is provided on the flat or substantially flat surface 1b of the glass substrate 1. Accordingly, the layers 3a-3f are substantially flat or planar in such exemplary embodiments of this Invention. Alternatively, in other representative embodiments, the inner surface 1b of the glass substrate 1 may be as patterned as the outer textured surface 1a.

In some representative embodiments of this invention, the photovoltaic device can be fabricated by providing a glass substrate 1 and then placing (e.g., by dispersion or other suitable technique) a multilayer electrode 3 on the substrate 1. The structure is then coupled to The substrate (1) and front electrode 3 are interconnected with the rest of the device to form the photovoltaic device shown in Figure 1. For example, the semiconductor layer 5 can then be formed on the front electrode on substrate 1. Alternatively, the back contact 7 and semiconductor layer 5 can be fabricated or formed on the substrate 11 (e.g., glass or other suitable material) first, and then the electrode (3) and dielectric layer 2 can be formed on the semiconductor layer 5, encased in substrate 1 via an adhesive such as EVA.

The different nature of the TCO layers 3a, 3c, and/or 3e, and the two mainly metal IR-reflecting and conducting layers 3b and/or 3d, are also useful in achieving one, two, three, four, or all The following benefits: (a) Low sheet resistance (Rs) of the overall electrode 3 thus increasing the conductivity and improving the overall output power of the photovoltaic module output power; (b) increasing the reflection of infrared (IR) radiation by electrode 3 and thus reducing the operating temperature of the semiconductor portion 5 of the photovoltaic module in order to increase the output power of the module; (c) Reduce reflection and/or increase light transmission in the visible region of 450-700 nm (and/or 450-600 nm) Using the front electrode 3, this leads to an increase in the output power of the photovoltaic module. (d) Reducing the overall thickness of the front electrode 3 packing material, which can reduce manufacturing costs and/or time; and/or (e) improving or enlarging the curing window when forming the TCO layer(s) due to the reduced effect of the conductivity of the TCO layers on the overall electrical properties of the module given the presence of a primarily metal layer(s) that is highly conductive; And/or (f) the lowering of the severity of the thermal voltage that Module separation is caused by reflection of solar thermal energy and reduced temperature difference across the module.

The active semiconductor region or active semiconductor film (5) may comprise one or more layers and may be of any suitable material. For example, the active semiconductor film (5) of a type of photovoltaic device with single junction amorphous silicon (a-Si) comprises three semiconductor layers, namely a p-layer, an n-layer, and a i. The p-type a-Si layer of the semiconductor film (5) may form the upper part of the semiconductor film (5) in some embodiments of this invention; Typically, the I layer is located between the p and n layers. These amorphous silicon-based layers of the membrane (5) can be made of hydrogenated amorphous silicon in some cases, but can also be made of or can include hydrogenated amorphous silicon or germanium silicon. Hydrogenated amorphous silicon germanium, hydrogenated microcrystalline silicon, or other suitable material(s) in some embodiments of this invention. The active region may be of the double-link or triple-link type, in alternative embodiments of this invention. CdTe can also be used to manufacture a semiconductor film (5), in alternative embodiments of this invention.

The contactor, reflector, and/or back electrode 7 may be made of any suitable electrically conductive material. For example, but not limited to, the back contact or electrode (7) may be made of TCO and/or metal in some cases. Examples of TCO materials suitable for use as a contact or back electrode (7) include indium zinc oxide, indium-tin-oxide (ITO), tin oxide, and/or zinc oxide, which can be doped with aluminum (which can be It may or may not be alloyed with silver. The back contact (7) can be of a single-layer type or a multi-layer type in different cases. In addition, the back contact (7) can include both a TCO portion and a metal portion in some cases. For example, in an example of a multilayer embodiment, the TCO portion of the back contact (7) may include a layer of a material such as indium zinc oxide (which may or may not be doped with silver), indium-tin-oxide (ITO), tin oxide, and/or zinc oxide, as close as possible to the active region (5), and the back contact may include another conductive and possibly reflective layer of a material such as silver, molybdenum, platinum, steel, or iron. iron, niobium and titanium, chromium, bismuth, antimony, or aluminum, furthest from the active region (5) and closest to the superstate (11). The metal portion could be closer to the superstate (11) compared to the TCO part of the back contact (7).

The photovoltaic module may be encapsulated or partially covered with an encapsulant such as encapsulation material (9) in some exemplary embodiments. A representative encapsulation material or adhesive for layer (9) is EVA or PVB. However, other materials such as Tedlar type plastic, Nuvasil type plastic, Tefzel type plastic or similar can be used for the layer (9) in different cases.

The use of the two essentially metal, IR-reflecting, and highly conductive layers 3b and 3d, and the TCO layers 3a, 3c, and 3d, to form a multilayer front electrode (3) allows for improved performance of the photovoltaic (PV) device incorporating a film. Thin by lowering the plate resistance (and increasing conductivity) and tailored reflection and light transmission spectra that best suit the response of the photovoltaic (PV) device. The refraction indices of glass 1, hydrogenated a-Si as an example of a semiconductor (5), Ag as an example of layers 3b and 3d, and an example of TCO, have been shown in Figure 2. Based on these refractive indexes (n), the refractive indexes (n) have been shown. The expected transmittance of rays that strike the semiconductor (5) from the incident surface of the substrate (1), in Figure 3. Specifically, Figure 3 is a curve showing the percentage of transmittance (T%) versus wavelength (nm), which shows the transmittance spectra to a thin film made of hydrogenated Si (5) for a photovoltaic device to compare examples 1-3. of this invention (see Examples 1-3 in Figures 5-7) versus a comparative example (reference TCO). The TCO referred to as a reference was manufactured from a glass substrate (1) with a thickness of 3 mm, and extending outward starting from the glass, we find a tin oxide layer with a thickness of 3 nanometers, a silicon oxide layer with a thickness of 20 nanometers, and a TCO layer with a thickness of 350 nanometers. Thus, Figure 3 shows that the examples of this invention (Examples 1-3 shown in Figures 5-7) have increased the transmittance in the wavelength range from 450-600 and 450-700 nm, and this has led to an increase in the output power of the typical photovoltaic unit. , compared to the comparative example (reference TCO).

Example 1, shown in Figure 5 and shown graphically in Figures 3-4, was manufactured from a glass substrate (1) with a thickness of 3 mm, a dielectric layer (2) of TiO2 with a thickness of 16 nm, and a TCO layer (zinc oxide) with a thickness of 10 nm. nanometer-thick Al-doped Ag (3b), an IR-reflecting Ag (3b) layer 8 nm thick, and a 115-nm-thick zinc oxide TCO layer doped with Al (3e). Layers 3C, 3D, and 3F were not present in Example 1. Example 2 shown in Figure 6 and shown graphically in Figures 3-4 was manufactured from a glass substrate (1) 3 mm thick, a dielectric layer (2) of TiO2 16 nanometers thick, and a TCO layer of zinc oxide 10 nanometers thick. Meter doped with Al (3a), an IR-reflecting Ag layer (3b) 8 nm thick, a TCO layer 100 nm thick zinc oxide doped with Al (3e), and a titanium semi-oxide layer (3f) 20 nm thick. . Example 3 shown in Figure 7 and shown graphically in Figures 3-4 was manufactured from a glass substrate (1) 3 mm thick, an insulating layer (2) 45 nm thick, and a TCO layer of zinc oxide 10 nm thick doped with Al ( 3a), an IR-reflecting Ag layer (3b) with a thickness of 5 nm, a 75-nm-thick TCO layer of zinc oxide doped with AL (3c), an IR-reflecting Ag layer (3d) with a thickness of 7 nm, and a layer (3f) of... Titanium oxide thickness is 20 nanometers. These single- or double-layer silver coatings used in Examples 1-3 had sheet resistances of less than 10 ohms/square and 6 ohms/square, respectively, and had an overall thickness much less than the 400 nm thickness. meters used in prior art. Examples 1-3 had transmittance spectra plotted as needed, as shown in Figure 3, with a transmittance greater than 80% to the semiconductor (5) in part or all of the wavelength range of about 450-600 nm and/or 450-700 nm, where AM1.5 had the strongest intensity and photovoltaic devices can have substantially higher or higher quantum efficiencies.

Meanwhile, Figure 4 is a curve showing the percentage of reflectance (R%) versus wavelength (nm) showing the reflectance spectra from a hydrogenated Si thin film for a photovoltaic device to compare Examples 1-3 with the aforementioned comparative example. ; This shows that Examples 1-3 have increased reflectance in the IR range which reduces the operating temperature of the photovoltaic module resulting in increased module output, compared to the comparative example. In Figure 4, the decrease in reflectance in the visible range of about 450-600 nm and/or 450-700 nm (the high efficiency range of the cell) is advantageously coupled with the increase in reflectance in the near and short IR range above about 1000 nm. ; Increased reflectance in the near and short IR range reduces the absorption of solar thermal energy, leading to improved cell output due to lower cell temperature and series resistors in the module. As shown in Figure 4, both the glass substrate (1) and the front electrode (3) combined have a reflectivity of at least about 45% (ideally at least about 55%) over a fairly large portion. Or in most of the near to short IR wavelength range of about 100-2500 nm and/or 1000-2300 nm. In some representative embodiments, they reflect at least 50% of the energy in the range 1000-2500 nm and/or 1200-2300 nm. In some representative embodiments, the front glass substrate and front electrode (3) combined have an IR reflectivity of at least about 45% and/or at least 55% over a fairly large portion or most of the near IR wavelength range of About 1000-2500 nm, and can be 1200-2300 nm. In some representative embodiments, they can block at least 50% of solar energy in the range of 1000-2500 nm.

While electrode (3) is used as a front electrode in a photovoltaic device in some representative embodiments of this invention that are described and illustrated herein, electrode (3) may also be used as a second electrode in connection with a photovoltaic device or succession.

Figure 8 is a cross-section view of a photovoltaic device according to another representative embodiment of this invention. An optional anti-reflective (AR) layer (1a) may be provided on the front glass substrate (1) in any embodiment of this invention, as referred to for example as the AR layer(s) (1a) shown in Figure 8 (e.g. (See also Figures 9-10). The photovoltaic (PV) device of Figure 8 includes a glass substrate (1), insulating layer(s) (2) (e.g., made of or comprising one or more of:

silicon oxide, silicon oxynitride, silicon nitride, titanium oxide, niobium oxide, and/or the like) which may act as a sodium barrier to prevent blocking sodium from moving off the front glass substrate (1); The seed layer (4b) (for example, is made of or includes:

zinc oxide, zinc aluminum oxide, tin oxide, tin antimony oxide, indium zinc oxide, or the like) wherein the TCO layer or dielectric layer may be in various exemplary embodiments; A silver-based IR reflective layer (4c), and an optional top coating or contact layer (4d) (e.g., made of or including Ni and/or Cr oxide, zinc oxide, zinc aluminum oxide, or the like) which can To be a TCO layer; The TCO layer (4e) (for example, is made of or includes:

zinc oxide, zinc aluminum oxide, tin oxide, tin antimony oxide, zinc tin oxide, indium tin oxide, indium zinc oxide

or something similar); An optional protective layer, (for example, made of or including:

zinc oxide, zinc aluminum oxide, tin oxide, tin antimony oxide, zinc tin oxide, indium tin oxide, indium zinc oxide

or similar) where it can be somewhat conductive; semiconductor (5) (e.g., CdS/CdTe, a-Si, or similar); Optional contactor, reflector, and/or back electrode (7); Optional adhesive layer (9), and optional glass substrate 11. It should be noted that in some representative embodiments, layer (4b) may be the same as layer (3a) previously described above, and layer (4c) may be the same as layer (3b) or (3d) previously described above, ( This also applies to Figures 8-10, and layer (4f) could be the same as layer (3f) that was previously described above (this also applies to Figures 8-10) (see the advanced description above for an explanation of other models in this regard). Likewise, layers 1, 5, 7, 9, and 11 have also been discussed above in relation to other embodiments, such as surfaces 1a and 1b of the glass front substrate 1.

For illustrative purposes only, an example of a Figure 8 template will be provided as follows (note that some of the optional layers shown in Figure 8 are not used in this example). For example, referring to Figure 8, a glass substrate (1) (e.g., about 3.2 mm thick) was used, and a dielectric layer (2) (e.g., silicon oxynitride with a thickness of about 20 nm can be followed by a TiOx insulating layer). about 20 nm thick), an Ag core layer (4b) (e.g. dielectric layer, zinc oxide TCO layer, or zinc aluminum oxide about 10 nm thick), and an IR reflective layer (4c) (of silver with a thickness of about 20 nm). about 5-8 nm), TCO (4e) layer (e.g. zinc oxide layer, tin oxide, zinc aluminum oxide, ITO, conductive thicknesses of 50-250 nm (preferably about 100-150 nm), and an optional conductive protective layer (4f) (zinc oxide TCO, tin oxide, zinc aluminum oxide ITO, or similar Similar, with a thickness ranging from about 10-50 nm). In some representative embodiments, the protective layer 4f (or 3f) is designed to have a refractive index (n) of about 2.1 to 2.4, preferably from about 2.15 to 2.35, where the refractive index closely matches that of the semiconductor (n). 5) (eg, CdS or similar) in order to improve the efficiency of the device.

The photovoltaic (PV) device shown in Figure 8 can have a sheet resistance of no more than about 18 ohms/square, and it is preferable that it does not exceed about 15 ohms/square, and it is even better that it does not exceed about 13 ohms/square in Some representative examples of this invention. Furthermore, the model shown in Figure 8 can have transmittance spectra plotted as needed with a transmittance greater than 80% to the semiconductor (5) in part or all of the wavelength range of about 450-600 nm and /or 450-700 nm, where AM1.5 can have the highest intensity and in some representative cases the cell has the highest or substantially the highest quantum efficiency.

Figure 9 is a cross-section view of a photovoltaic device according to another representative embodiment of this invention. The photovoltaic (PV) device of the embodiment shown in Figure 9 includes an optional anti-reflection (AR) layer (1a) on the light incident side of the front glass substrate (1), a first dielectric layer (2a), and a second insulating layer (2b). ), and a third insulating layer (3C) which may optionally serve as a core layer (e.g., made of or comprising zinc oxide, zinc aluminum oxide, tin oxide, indium tin oxide, indium zinc oxide, or the like) for the silver-based layer. silver (4C), and a conductive layer that reflects infrared rays Silver-based IR (4C), and an optional top coat or contact layer (4D) (e.g., made of or including Ni and/or Cr oxide, zinc oxide, zinc aluminum oxide, or the like) which can be TCO or insulating layer, and RCO (4e) layer (e.g., comprising one or more layers, e.g. made of or comprising zinc oxide, zinc aluminum oxide, tin oxide, indium tin oxide, zinc tin oxide, indium tin oxide, indium zinc oxide , or the like), and an optional protective layer (4f) (e.g., made of or including zinc oxide , zinc aluminum oxide, tin oxide, indium tin oxide, zinc tin oxide, indium tin oxide, indium zinc oxide, or the like) where they may be more or less conductive, and semiconducting (5) (e.g., one or more layers Such as CdS/CdTe, a-Si or similar), contactor, reflector, and/or electrode (7) optional back, optional adhesive (9), and optional glass substrate (11). The semiconductor film (5) may comprise a single pin or pn semiconductor structure, or a double semiconductor structure in various embodiments of this invention. The semiconductor may be, or may comprise, silicon in some representative cases. In other exemplary embodiments, the semiconductor film (5) may comprise a first layer made of or comprising CdS (e.g., a permeable layer) adjacent or close to the layer(s) (4e) and/or (4f) and a semiconductor layer A second made of or including CdTe (e.g., a primary absorbent layer) adjacent or close to the electrode or back contact 7.

Referring to an embodiment of Fig. 9 (and an embodiment of Fig. 10), in some representative embodiments, a first dielectric layer (2a) with a relatively low refractive index (n) is used (e.g., n ranges from about 1.7 to 2.2, preferably from about 1.8 to 2.2, preferably from about 1.95 to 2.1, and most preferably from about 2 to 2.08), and a second dielectric layer (4b) with a relatively large refractive index (n) (compared to layer (2a)) (e.g. n ranges from about 2.2 to 2.6, and best from about 2.3 to 2.5, most preferably from about 2.35 to 2.45), and a third dielectric layer (2c) with a relatively low refractive index (n) (compared to layer 2b) (e.g., n from about 1.8 to 2.2, preferably from about 1.95 to 2.1, most preferably From about 2 to 2.05). In some exemplary embodiments, the first low-refraction insulating layer (2a) may be made of, or may comprise, silicon nitride, silicon oxynitride, or other suitable material, and the second low-refraction insulating layer (2b) may be made The third insulating layer (2c) may be made of, or may comprise, zinc oxide or other suitable material. In some exemplary embodiments, layers 2a-2c are combined to form a combined layer with a good compatible refractive index that also serves as a buffer against sodium migration from the glass (1). In some exemplary embodiments, the thickness of the first insulating layer (2a) ranges from about 5 to 30 nm, preferably from about 10 to 20 nm, and the thickness of the second insulating layer (2b) ranges from about 5 to 30 nm, preferably from about 10 nm. - 20 nanometers, and the third insulating layer (2C) is thinner and its thickness ranges from about 3-20 nanometers, preferably from about 5-15 nanometers, and most preferably from about 6-14 nanometers. While layers 2a, 2b, and 2c are insulating in some embodiments of this invention, one, two, or all three of these layers may be insulating or TCO in some other representative embodiments of this invention. Layers (2b) and (2c) are metal oxides in some representative embodiments of this invention, while layer (2a) is metal oxide, metal nitride, or silicon nitride in some representative cases. Layers 2a and 2c can be deposited by spraying or any other suitable method.

Also referring to Embodiment of Figures 9 (and Embodiments of Figures 10 - 11), the TCO layer(s) (4e) may be made of or may comprise a suitable TCO including, without limitation, zinc oxide, and/or zinc aluminum oxide, tin oxide, and/or the like. A TCO layer or TCO row (4e) can include multiple layers in some representative cases. For example, in some cases, the TCO layer (4) comprises a first metal oxide TCO layer (e.g., zinc oxide) adjacent to the Ag layer (4c), the top Ag layer (4d), and a second layer of Ag Metal oxide TCO (e.g. tin oxide) close to the contact layer (4f) and/or (5).

For illustrative purposes only, an example of a sample figure of Figure 9 is shown as follows. For example, referring to Figure 9, a glass substrate (1) (e.g., loose glass with a thickness of about 3.2 mm, with a refractive index (n) of about 1.52) is used, and a first dielectric layer (2a) (e.g. silicon nitride, about 15 nm thick, with a refractive index (n) of about 2.07), and a second dielectric layer (2b) (e.g. Ti oxide, such as TiO2 or other suitable equivalent material, about 16 nm thick, with a refractive index refractive index (n) is about 2.45), and the dielectric layer A third (2c) (for example, zinc oxide, which can be doped with Al, is about 9 nanometers thick, and has a refractive index (n) of about 2.03), and an IR reflective layer (4c) (of silver with a thickness ranging from -5 8nm, e.g. 6nm), a topcoating layer comprising silver (4d) made from 1-3nm NiCrOx which may or may not be oxidation graded, and a TCO (4e) film (e.g. , zinc oxide, zinc aluminum oxide, and/or tin oxide, conductive, with a thickness of 10-150 nm), and a semiconducting film (5) comprising a first layer of CdS (e.g., about 70 nm) as proximal as possible to the substrate (1), a second layer of CdTe as furthest as possible from the substrate (1), a contact or back electrode (7), and an optional adhesive layer ( 9), and optional substrate 11.

The photovoltaic (PV) device shown in Figure 9 (and/or Figures 10-11) may have a sheet resistance of no more than about 18 ohms/square, and it is preferable that it does not exceed 15 ohms/square. Exceeding 13 ohms/square in some representative embodiments of this invention. Furthermore, a sample of Figure 9 (and/or Figure 10) can have transmittance spectra plotted as needed with a transmittance greater than 80% in the semiconductor (5) in part or all of the wavelength range of about 450-600. nm and/or 450-700 nm, where AM1.5 can have the highest intensity.

Figure 10 is a cross-section view of a photovoltaic device according to another representative embodiment of this invention. The model of Figure 10 is completely similar to the model of Figure 9 discussed above, except for the TCO membrane (4e). In an embodiment of Figure 10, the TCO film (4e) includes a first layer (4e) made of or comprising a first metal oxide TCO (e.g., zinc oxide, which may or may not be doped with Al or the like) adjacent and touching the layer (4d); and a second layer (4e) of a second metal oxide TCO (e.g., tin oxide) adjacent to and in contact with layer (4f) and/or (5) (e.g., layer (4f) may be omitted, as in previous embodiments). Layer 4e is considerably thicker than layer 4e in some representative models. In some representative embodiments, the first TCO layer (4e) has a greater resistivity than the second TCO layer (4e). In some exemplary embodiments, the first TCO layer (4e) may be zinc oxide, zinc oxide doped with Al, or ITO, having a thickness of 70-150 nm (e.g., about 110 nm) and having a resistivity of no more than About 1 ohm. cm, and the second TCO layer (4Ha) can be made of tin oxide and range in thickness from about 10-50 nm (eg, about 30 nm) and have a resistivity of about 10-100 ohms. cm, and it can range from about 2-100 ohms. poison. The first TCO layer (4e) is thicker and has a higher conductivity than the second TCO layer (4e) in some representative models, and this is useful as the layer (4e) is closer to the Ag-based conductive layer (4c) and this leads to improving the efficiency of the photovoltaic device. photovoltaic (PV) device. Moreover, this design is unique in that the CdS of the film (5) adheres well to tin oxide, which can be used in the layer (4e) or can be made from it. The TCO 4e and/or (4e) layers can be deposited by spraying or other suitable method.

In some representative cases, the first TCO layer (4e) may be made from or comprise ITO (indium tin oxide) instead of zinc oxide. In some representative cases, the ITO oxide of layer 4e may comprise about 90% In, 10% Sn, or alternatively about 50% In, 50% Sn.

Using at least these three layers of insulation, such as 2a-2c, is beneficial in that reflections can be reduced, resulting in a more efficient photovoltaic device. Furthermore, the top coating 4d (e.g., made of or comprising Ni and/or Cr oxide) may be oxidation graded, continuously or discontinuously, in some embodiments of this invention. Specifically, layer 4d can be designed to be more metallic (less oxidized) at a position closer to the Ag-based layer (4d) than at a position further away from the Ag-based layer (4d); This has been found to be beneficial for thermal stability purposes in that the coating does not degrade significantly during the extremely high temperature processing that can accompany the manufacture of a photovoltaic (PV) device or other process.

In some representative embodiments of this invention, it has been interestingly found that any thickness of about 120-160 nm, preferably about 130-150 nm (e.g., 140 nm), of the TCO membrane (4e) is advantageous in that Jsc peaks in this range. For thinner TCO films, the Jsc peaks decrease by up to about 6.5% until reaching a minimum at a TCO thickness of about 60 nm. Below 60 nm, it increases again until a TCO (4e) film with a thickness of 15-35 nm (preferably 20-30 nm) becomes attractive, but such coating layers may not be desirable in some representative cases. Non-exclusive. Therefore, to obtain a reduction in short-circuit current for CdS/CdTe photovoltaic devices in some representative cases, a TCO (4e) film may be provided with thicknesses in the range of about 15-35 nm, or in the range of about 120 nm. - 160 nm or 130-150 nm.

Figure 11 is a cross-section view of a photovoltaic device according to another representative embodiment of this invention. The model of Figure 11 is completely similar to the models of Figure 9 11 previously discussed above, except for the differences shown in the figure. Figure 11 is a cross-section view of a photovoltaic device according to another representative embodiment of this invention. The photovoltaic device shown in Figure 11 may include: Optional anti-reflection (AR) coating (1a) on the light incident side of the front glass substrate 1; A first dielectric layer (2a) made of or comprising one or more of silicon nitride (e.g., Si3N4 or other suitable chemical equivalent), silicon oxynitride, silicon oxide (e.g., SiO2 or other suitable chemical equivalent), and/or tin oxide (e.g., SnO2 or other suitable chemical equivalent); A second dielectric layer (3b) made of or comprising titanium oxide (e.g., TiO2 or other suitable chemical equivalent) and/or niobium oxide; layer A third (2c) (which may be an insulating or TCO layer) may optionally act as a core layer (e.g., a layer made of or comprising zinc oxide, zinc aluminum oxide, tin oxide, indium tin oxide, indium zinc oxide, or the like). That) for the silver-based layer (4C); A top coating or contact layer 4D (which may be insulating or conducting) is made of or comprises Ni and/or Cr oxide, NiCr, Ti, Ti oxide, zinc aluminum oxide, or the like; TCO layer (4e) (eg, comprising one or more layers) made of or comprising zinc oxide, zinc aluminum oxide, tin oxide, indium tin oxide, zinc tin oxide, indium tin oxide, indium zinc oxide, and/or zinc gallium aluminum oxide Optional protective layer (4f) that can be TCO in certain cases (e.g. manufactured of or comprising zinc oxide, zinc aluminum oxide, tin oxide, indium tin oxide, zinc tin oxide, indium tin oxide, indium zinc oxide, oxide titanium, or the like) which may be more or less conductive; Semiconductor film (5) made of or comprising one or more layers e.g CdS/CdTe, a-Si, or the like (e.g., the film (5) may be made of a layer fabricated or comprising CdS adjacent to the layer (4f), a layer fabricated or comprising CdTe adjacent to the layer (7) of aluminum or similarly; an optional adhesive 9 made of or including a polymer such as PVB and an optional glass backing substrate 11; In some representative embodiments of this invention, the thickness of the insulating layer 2a can range from about 10 to 12 nm, preferably from about 12 to 18 nm; The thickness of layer 2b can range from about 10-20 nanometers, and preferably from about 12-18 nanometers. The thickness of layer 2c can range from about 5 to 20 nm, preferably from about 5 to 15 nm (with layer 2c being thinner than one or both of layers 2a and 2b in some representative embodiments); The thickness of layer 4c can range from about 5-20 nanometers, and preferably from about 6-10 nanometers. And it can The thickness of the 4D layer ranges from about 0.2 to 5 nm, preferably from about 0.5 to 2 nm; The thickness of the TCO (4e) film can range from about 50-200 nm, preferably from about 75-150 nm, and can have a resistance of no more than about 100 milliohms in some representative cases; The thickness of the barrier layer 4F can range from about 10-50 nanometers, preferably from about 20-40 nanometers, and it can have a resistance not exceeding about 1 megaohm cm in some representative cases. Furthermore, the surface of the glass 1 closest to the sun can be shaped to have a repeating pattern by scratching or the like, in some representative embodiments of this invention.

An optional barrier layer (4f) can provide a substantial refraction match between the semiconductor film (5) (e.g., CdS portion) up to the TCO film (4e) in some representative embodiments, in order to improve the overall transmittance to sunlight up to semiconductor (4e). Mosul.

Also referring to embodiments of Figure 11, the semiconductor film (5) may comprise a single pin or pn semiconductor structure, or a tandem semiconductor structure in various embodiments of this invention. The semiconductor film (5) may be embedded or include silicon in some exemplary cases. In other exemplary embodiments, the semiconductor film (5) may comprise a first layer made of or comprising CdS (e.g., a permeable layer) adjacent or closest to the layer(s) 4e and/or 4f and a second semiconductor layer made of or including On CdTe (e.g. main absorber) close or closest to the electrode or back contact 7.

Referring also to Figure 11, in some representative embodiments, the first dielectric layer 2a has a relatively low refractive index (n) (e.g., n ranges from about 1.7 to 2.2, preferably from about 1.8 to 2.2, even better from about 1.95 to 2.1 , most preferably from about 2 to 2.08), and the second insulating layer 2b has a relatively high refractive index (n) (compared to layer 2a) (e.g., n ranges from about 2.2 to 2.6, preferably from about 2.3 to 2.5, and most preferably from About 2.35 to 2.45), and can be about Optionally, the third insulating layer 2c has a relatively low refractive index (n) (compared to layer 2b) (e.g., n ranges from about 1.8 to 2.2, preferably from about 1.95 to 2.1, most preferably from about 2 to 2.05). In some representative embodiments, layers 2a-2c are combined to form a stack with good refractive index matching for anti-reflective purposes and which also serves as a protective layer to prevent sodium migration from the glass 1. In some exemplary embodiments, the thickness of the first insulating layer 2a ranges from about 5 to 30 nm, preferably from about 10 to 20 nm, and the thickness of the second insulating layer 2b ranges from about 5 to 30 nm, more preferably from about 10 to 20 nm. The third layer, 3C, is thinner and its thickness ranges from about 3-20 nanometers, preferably from about 5-15 nanometers, and most preferably from about 6-14 nanometers. While layers 2a, 2b, and 2c are insulating in some embodiments of this invention, one, two, or all three of these layers may be insulating or TCO in some other representative embodiments of this invention, while layer 2a is a metal oxide and/or nitride Or silicon nitride in other representative cases. Layers 2a-2c can be deposited by spraying or by any other suitable method.

Also referring to an example of Figure 11, the TCO layer(s) (4e) may be fabricated or may comprise any suitable TCO including, but not limited to, zinc oxide, zinc aluminum oxide, tin oxide, and/or the like. that. The TCO layer or membrane (4e) can comprise several layers in some representative cases. For example, in some cases, the TCO layer (4) includes a first metal oxide TCO layer (e.g., zinc oxide) adjacent to the Ag layer (4c), a top Ag layer (4d), and a second Ag layer (4d). A second metal oxide TCO (e.g. tin oxide) is close and in contact with layer (4f) and/or (5). The photovoltaic (PV) device shown in Figure 11 can have a sheet resistance of no more than about 18 ohms/square, and it is better that it does not exceed about 15 ohms/square, and it is better that it does not exceed about 13 ohms/square in Some representative examples of this invention. Furthermore, the model shown in Figure 11 can have transmittance spectra plotted as needed with a transmittance greater than 80% to the semiconductor (5) in part or all of the wavelength range of about 450-600 nm and /or 450-700 nm, where AM1.5 can have the highest intensity, in some exemplary embodiments of this invention.

Examples 4-5 are discussed below, each including a surface mounted 1a to the front glass substrate 1 as shown in the figures herein. In Example 4, the textured surface 1a of the permeable front glass substrate 1 is lightly etched and features fine features that act as a single layer of low-index antireflection coating suitable for, for example, CdTe solar cell applications. Example (5) has features on the composite surface 1(a) of the front glass substrate, again machined by etching, which trap incoming light, refracting the light in the semiconductor at oblique angles, suitable, for example, for individual solar cell applications and/or tandem a-Si. The inner surface 1b of the glass substrate (1) was flat in both Examples 4 and 5, as was the front electrode 3.

In Example 4, referring to Figure 11, the stack of moving layer of glass 1 was inward toward the semiconductor 5 glass 1, a silicon nitride layer (15 nm thick) 2a, a TiOx layer (16 nm thick) 2b, and a ZnA10x layer (10 nm thick) nm) 2c, Ag layer (7 nm thick) 4c, NiCrOx layer (1 nm thick) 4d, ITO layer (110 nm thick) 4e, SnOx layer (30 nm thick) 4f, and then the semiconductor CdS/ CdTe. The etched surface 1a of the front glass substrate 1 has an effective index and thickness of about 1.35-1.42 and 110 nm, respectively. The etched surface acts as an AR shell (although no such shell actually exists) and increases transmission by a rate of 2-3% which is considered very useful, throughout the 400-1000 nm wavelength region as shown in Figures 12-13. As shown in Figure 15, the combination of Ag-based TCC and composite front surface results in enhanced transmission in the semiconductor CdTe/CdS5 film, especially in the region of 500–700 nm where the CdTe photovoltaic device, QE, and solar flux, are important.

Figure 12 is the measured transmission (T) and reflection (R) spectra (% of surface I), versus wavelength (nm), showing the results from Example 4, where the example uses a 10 ohm/sq Ag-based TCC 3 shell. of a front glass substrate 1 having a composite surface 1. As shown above, Example 4 with a composite surface 1a has a slightly increased transmission (T) and a slightly decreased reflection (R) in the 500-700 nm region compared to the comparative example shown in FIG. 12 Where surface 1a (the first surface) was not etched. This is an advantage in that more current is produced in the semiconductor film 5 of the photovoltaic device. Figure 15 is a graph of transition percentage (T%) versus wavelength (nm) showing the transition spectrum in a CdS/CdTe cell for a photovoltaic device compared to Example 4 versus the comparative example. Figure 15 (expected transmission in the CdS /CdTe cell for the photovoltaic device in the CdTe solar cell module of Example 4, which includes the different front substrates) shows that Example 4 achieved increased transmission at approximately 500-700 nm wavelength range, and thus module output power Increased photovoltaic modularity compared to the comparative example without the etched front surface (dotted line

In Example 5, referring to Figure 11, the stack of moving layer of glass 1 was inward toward the semiconductor 5 of glass 1, a silicon nitride layer (15 nm thick) 2a, a TiOx layer (10 nm thick) 2b, and a ZnA10x layer (thick 10 nm) 2c, Ag layer (8 nm thick) 4c, NiCrOx layer (1 nm thick) 4d, ITO layer (70 nm thick) 4e, SnOx layer (20 nm thick) 4f, and then semi- Conductor a-Si. Figure 14 shows measured and expected results; The measured integrated visible transmission spectrum and expected light scattering/propagation, according to Example 5.

Figure 14 shows that the integrated transmission that includes both visible and diffuse propagation light is about 17% higher than that of visible-only propagation light. This means that more than 17% of the light in the near-infrared and visible regions is either scattered or distributed. Scattered and/or diffused light increases the optical path in photovoltaic materials5, and is particularly required in a-Si solar cells.

While the invention has been described in relation to what may at present be considered the preferred and most practicable embodiment, it should be understood that the invention is not limited to the disclosed embodiment, but, on the contrary, that the invention is intended to cover various equivalent modifications and arrangements. Which are included within the content and scope of the attached protection elements.