Solar cell

Solar battery

[New technology range]

The present invention relates to a solar cell, and more particularly to a solar cell having high photoelectric conversion efficiency.

Referring to FIG. 1 , a general solar cell is configured by sequentially forming a first conductive layer 12 , a photoelectric conversion layer 13 , and a second conductive layer 14 on a top surface of a glass substrate 11 . When in use, the incident light is irradiated upward through the bottom surface of the glass substrate 11. After being refracted, the light passes through the glass substrate 11 and the first conductive layer 12, and then reaches the photoelectric conversion layer 13 to cause the photoelectric conversion layer 13 to generate an electron current and a hole flow. And passing through the first and second conductive layers 12, 14 to the outside.

However, generally, the interface between the first conductive layer 12 and the photoelectric conversion layer 13 is a plane, and before the incident light is refracted into the photoelectric conversion layer 13, a part of the light source is reflected by the plane between the first conductive layer 12 and the photoelectric conversion layer 13 Far from the photoelectric conversion layer 13, the light source is not completely absorbed by the photoelectric conversion layer 13, resulting in a low efficiency of the solar cell.

Therefore, the object of the present invention is to provide a solar cell having high photoelectric conversion efficiency.

Therefore, the solar cell of the present invention comprises: a transparent substrate, a first conductive layer which is transparent and is laid on the top surface of the transparent substrate, a metal oxide layer which is laid on the top surface of the first conductive layer, and a metal layer which is laid on the metal a photoelectric conversion layer on the top surface of the oxide layer, and a second conductive layer on the top surface of the photoelectric conversion layer. The metal oxide layer is made of a transparent and electrically conductive aluminum-doped zinc oxide material, and the top surface of the metal oxide layer is etched into a sharp concavo-convex shape.

Forming a metal oxide layer formed on the top surface of the first conductive layer and made of aluminum-doped zinc oxide material to reduce the impedance of the conduction current, and etching the top surface by etching the metal oxide layer It can reduce the sawtooth shape or pyramid shape of the light source reflection and improve the photoelectric conversion efficiency.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments.

Referring to FIG. 2 and FIG. 3, a first preferred embodiment of the solar cell of the present invention comprises a transparent substrate 2, and a first conductive layer 3, a metal oxide layer 4, and a first layer disposed on the top surface of the substrate 2. The photoelectric conversion layer 5 and a second conductive layer 6.

In the embodiment, the substrate 2 is made of glass material, but in actual implementation, it can also be made of other light-transmitting materials, and the implementation range is not limited to the material of the substrate 2.

The first conductive layer 3 is laid on the top surface of the transparent substrate 2. The first conductive layer 3 is made of a transparent conductive material. In this embodiment, the material of the first conductive layer 3 is selected from indium tin oxide or indium zinc oxide, but the implementation is not in the first conductive layer 3. The material is limited.

The metal oxide layer 4 is made of a transparent and electrically conductive aluminum-doped zinc oxide material, and is laid on the top surface of the first conductive layer 3, and the top surface of the metal oxide layer 4 is etched into a shape of sharp irregularities. In this embodiment, the top surface of the metal oxide layer 4 is etched into a sawtooth shape, but in practice, the top surface of the metal oxide layer 4 may be etched into other tapered shapes, and the implementation range is not at the top of the metal oxide layer 4. The shape of the face is limited.

The photoelectric conversion layer 5 is laid on the top surface of the metal oxide layer 4, and the photoelectric conversion layer 5 can receive the light source 71 irradiated by the substrate 2, and generates a photoelectric effect to form an electron current and a hole flow.

The second conductive layer 6 is made of a conductive material and laid on the top surface of the photoelectric conversion layer 5, and the electron flow and the hole flow are output to the outside through the first and second conductive layers 6 for use. The photoelectric conversion layer 5 and the second conductive layer 6 are not characterized by the present invention, and will not be further described below.

Therefore, since the metal oxide layer 4 is transparent and has good conductive properties, when the metal oxide layer 4 is superposed on the top surface of the first conductive layer 3, it is equal to being parallel to the top surface of the first conductive layer 3. The surface resistance of the first conductive layer 3 is lowered, and the loss of electron flow and hole flow of the first conductive layer 3 and the metal oxide layer 4 is reduced. More importantly, the shape of the predetermined design can be engraved on the top surface of the metal oxide layer 4 by etching technology, so that when the light source 71 passing through the first conductive layer 3 reaches the top surface of the metal oxide layer 4, part of the light source 72 is refracted into the photoelectric conversion. Layer 5, part of the light source 73 is reflected by the oblique top surface of the metal oxide layer 4, and when irradiated to the other inclined surface, part of the light source 74 is refracted into the photoelectric conversion layer 5, and some of the light source 75 reflects, that is, the metal oxide layer 4 is used. The serrated top surface reduces the light source that is reflected away from the photoelectric conversion layer 5, improving the efficiency of the solar cell.

The following is a detailed description of the relationship between the size range and the surface resistance of the first conductive layer 3 and the metal oxide layer 4 of the present invention: in the embodiment, the thickness of the first conductive layer 3 ranges from 1500 to 2000 angstroms ( Angstrom, 10-10 square meters, the metal oxide layer 4 is formed on the top surface of the first conductive layer 3 to a thickness ranging from 4000 to 8000 angstroms.

Please also refer to Table 1. Table 1 shows the thickness of the first conductive layer 3 and the metal oxide layer 4 and the corresponding surface resistance value. When the thickness of the first conductive layer 3 is 2000 angstroms, the sheet resistance is about 9 Ω/. When the thickness of the metal oxide layer 4 is 8000 angstroms, the sheet resistance is about 10 Ω/, and when the first conductive layer 3 having a thickness of 2000 Å and the metal oxide layer 4 having a thickness of 8000 angstroms are provided, the sheet resistance can be greatly reduced to 4.7 Ω. /, reducing the loss of the electron flow or the hole flow generated by the photoelectric conversion layer 5, but the overall manufacturing cost is increased by 65%, and the excessively large metal oxide layer 4 also greatly affects the transmittance of the light source, Considering the cost and transmittance, the thickness of the first conductive layer 3 is necessarily less than 2000 angstroms, and the thickness of the metal oxide layer 4 must be less than 8000 angstroms.

<tables><img file="TWM354858U_D0001.tif" /></tables>

In addition, when the first conductive layer 3 has a thickness of 1500 angstroms, the sheet resistance is about 15 Ω/, and when the metal oxide layer 4 has a thickness of 4000 angstroms, the sheet resistance is about 20 Ω/, and the combined sheet resistance is about 8.6. Ω/, if the thickness of the first conductive layer 3 is less than 1500 angstroms, and the thickness of the metal oxide layer 4 is less than 4000 angstroms, the surface resistance is more than 9 Ω/, and there is a disadvantage that the electron current or the hole flow loss is too large. .

The first conductive layer 3 of the preferred embodiment has a thickness of 1500 angstroms. The metal oxide layer 4 has a thickness of 4500 angstroms and a valley thickness of 500 angstroms. The combined surface resistance is about 8.2 Ω/, which reduces current loss.

And most importantly, after the metal oxide layer 4 is disposed on the top surface of the first conductive layer 3, the shape of the sawtooth surface or the tapered surface can be carved on the top surface of the metal oxide layer 4 by etching to enhance the light source entering. The ratio of the photoelectric conversion layer 5, after the experimental test of the novel solar cell, if the metal oxide layer 4 is etched into a zigzag shape, and the etched peak thickness is 3900 to 7000 angstroms, and the trough thickness is 100 to 1000 angstroms, Can greatly increase the photoelectric conversion efficiency of 1 to 3%.

The structure of the second preferred embodiment of the novel solar cell is substantially the same as that of the first preferred embodiment, except that the top surface of the metal oxide layer 4 is etched into a square pyramid shape to reduce the reflection of the light source away from the photoelectric conversion. Layer 5 improves the photoelectric conversion efficiency.

In summary, the present invention reduces the conduction current impedance by forming a metal oxide layer 4 formed on the top surface of the first conductive layer 3 and doped with aluminum-doped zinc oxide, and is etchable by the metal oxide layer 4. The characteristic is that the saw tooth shape or the pyramid shape which can reduce the reflection of the light source is etched on the top surface thereof, and the photoelectric conversion efficiency is improved, so that the object of the present invention can be achieved.

However, the above description is only a preferred embodiment of the present invention, and the scope of the present invention cannot be limited thereto, that is, the simple equivalent change and modification made by the novel patent application scope and the novel description content, All remain within the scope of this new patent.

<p>2Substrate</p><p>3First conductive layer</p><p>4metal oxide layer</p><p>5Photoelectric conversion layer</p><p>6Second conductive layer</p><p>71~75Light source</p>

1 is a side view of a general solar cell; FIG. 2 is a perspective view of a first preferred embodiment of the solar cell of the present invention; FIG. 3 is a side cross-sectional view of the preferred embodiment of the first preferred embodiment; A perspective view of a second preferred embodiment of a novel solar cell.