KR20140046712A - Thin film solar cell - Google Patents

Abstract

The thin film solar cell according to the present embodiment includes a substrate; A first electrode formed on the substrate; A plurality of photoelectric conversion parts formed on the first electrode; And a second electrode formed on the photoelectric converter. The plurality of photoelectric conversion units may be formed on the first electrode to perform photoelectric conversion using light of a first wavelength band, and may include a first p-type semiconductor layer, a first i-type semiconductor layer, and a first n-type semiconductor layer. A first photoelectric conversion unit comprising; And a photoelectric conversion function using light of a second wavelength band formed on the first photoelectric conversion part and larger than the first wavelength band, and including a second p-type semiconductor layer, a second i-type semiconductor layer, and a second n-type semiconductor. And a second photoelectric converter including a layer. The first i-type semiconductor layer and the second i-type semiconductor layer have different thicknesses in consideration of the amount of light in the first wavelength band and the second wavelength band in each region.

Description

Thin Film Solar Cells {THIN FILM SOLAR CELL}

The present invention relates to a thin film solar cell, and more particularly, to a thin film solar cell in consideration of the actual use environment.

With the recent depletion of existing energy sources such as oil and coal, interest in alternative energy to replace them is increasing. Among them, solar cells are attracting attention as a next-generation battery which converts solar energy directly into electrical energy using semiconductor devices.

The solar cell uses a p-n junction, and can be classified into a silicon solar cell, a compound solar cell, a dye-sensitized solar cell, and a thin film solar cell. Among them, a thin film solar cell formed by depositing an electrode and silicon on a substrate has a low manufacturing cost and a large area. However, the thin film solar cell does not have excellent efficiency and output, and has a problem that is difficult to be applied to various real environments.

The present invention seeks to provide a thin film solar cell that can have excellent efficiency and output in a practical environment.

The thin film solar cell according to the present embodiment includes a substrate; A first electrode formed on the substrate; A plurality of photoelectric conversion parts formed on the first electrode; And a second electrode formed on the photoelectric converter. The plurality of photoelectric conversion units may be formed on the first electrode to perform photoelectric conversion using light of a first wavelength band, and may include a first p-type semiconductor layer, a first i-type semiconductor layer, and a first n-type semiconductor layer. A first photoelectric conversion unit comprising; And a photoelectric conversion function using light of a second wavelength band formed on the first photoelectric conversion part and larger than the first wavelength band, and including a second p-type semiconductor layer, a second i-type semiconductor layer, and a second n-type semiconductor. And a second photoelectric converter including a layer. The first i-type semiconductor layer and the second i-type semiconductor layer have different thicknesses in consideration of the amount of light in the first wavelength band and the second wavelength band in each region.

A thin film solar cell according to another embodiment of the present invention, a substrate; A first electrode formed on the substrate; A plurality of photoelectric conversion parts formed on the first electrode; And a second electrode formed on the photoelectric converter. The plurality of photoelectric conversion units may be formed on the first electrode to perform photoelectric conversion using light of a first wavelength band, and may include a first p-type semiconductor layer, a first i-type semiconductor layer, and a first n-type semiconductor layer. A first photoelectric conversion unit comprising; Forming a second p-type semiconductor layer, a second i-type semiconductor layer, and a second n-type semiconductor layer on the first photoelectric conversion part by using light of a second wavelength band larger than the first wavelength band. A second photoelectric conversion unit comprising; And a third p-type semiconductor layer, a third i-type semiconductor layer, and a third n-type semiconductor formed on the second photoelectric conversion part and performing photoelectric conversion using light in a third wavelength band larger than the second wavelength band. And a third photoelectric conversion unit including the layer. The first i-type semiconductor layer, the second i-type semiconductor layer, and the third i-type semiconductor layer are different from each other in consideration of the amount of light in the first wavelength band, the second wavelength band, and the third wavelength band in each region. Has a thickness.

According to this embodiment, by providing a thin film solar cell suitable according to the conditions of each region it is possible to maximize the efficiency and output of the thin film solar cell to increase the amount of power generation. That is, in the region where the light of the long wavelength range is relatively large and the region where the light of the short wavelength region is relatively large, the power generation amount may be increased by maximizing the efficiency and output of the thin film solar cell.

1 is a cross-sectional view of a thin film solar cell according to an embodiment of the present invention.
2 is a graph showing quantum efficiency according to each wavelength when the atmospheric mass index (AM) is 1.5.
3 is a graph illustrating quantum efficiency according to each wavelength in the case of the thin film solar cell of FIG. 1.
FIG. 4 is a graph showing quantum efficiency according to each wavelength in the case of the thin film solar cell of FIG. 1 according to another example.
5 is a cross-sectional view of a thin film solar cell according to another embodiment of the present invention.
FIG. 6 is a graph illustrating quantum efficiency according to each wavelength in the example of the solar cell of FIG. 5.
FIG. 7 is a graph illustrating quantum efficiency at each wavelength in the solar cell of FIG. 5 according to another example.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, it is needless to say that the present invention is not limited to these embodiments and can be modified into various forms.

In the drawings, the same reference numerals are used for the same or similar parts throughout the specification. In the drawings, the thickness, the width, and the like are enlarged or reduced in order to make the description more clear, and the thickness, width, etc. of the present invention are not limited to those shown in the drawings.

Wherever certain parts of the specification are referred to as "comprising ", the description does not exclude other parts and may include other parts, unless specifically stated otherwise. Also, when a portion of a layer, film, region, plate, or the like is referred to as being "on" another portion, it also includes the case where another portion is located in the middle as well as the other portion. When a portion of a layer, film, region, plate, or the like is referred to as being "directly on" another portion, it means that no other portion is located in the middle.

Hereinafter, a thin film solar cell according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view of a thin film solar cell according to an embodiment of the present invention.

Referring to FIG. 1, the thin film solar cell 10 according to the present exemplary embodiment includes a substrate 100, a first electrode 110, a photoelectric converter 120, and a second electrode 130. .

The substrate 100 may support the first electrode 110, the photoelectric converter 120, and the second electrode 130 formed thereon, and may be a material through which light can pass. In one example, the substrate 100 may be made of a non-conductive material having translucency, for example, glass or a polymer material.

The first electrode 110 formed on the substrate 100 may be made of a material (ie, a transparent conductive material) through which light may pass while having electrical conductivity. For example, the first electrode 110 is formed of at least one material selected from tin oxide (SnO ₂ ), zinc oxide (ZnO), or indium tin oxide (ITO), or a mixed material in which one or more impurities are mixed with a metal oxide. Can be. The first electrode 110 may be electrically connected to the photoelectric conversion unit 120 to collect and transfer electrons or holes (for example, holes) generated by light to the outside.

In the present exemplary embodiment, unevenness may be formed on the surface of the first electrode 110 (that is, the surface opposite to the substrate 100 and adjacent to the photoelectric converter 120). Such irregularities may be formed by texturing or the like and may have various shapes (eg, random pyramid shapes). If unevenness is formed on the surface of the first electrode 110 by such texturing and the surface roughness is increased, the reflectance of the incident light can be lowered. Therefore, the light absorption rate can be increased, and the efficiency of the thin film solar cell 10 can be improved.

In this case, since the unevenness is formed on the surface of the first electrode 110 as described above, each of the layers of the photoelectric conversion part 120 sequentially formed thereon also have unevenness on both surfaces. In addition, one surface of the second electrode 130 (the surface adjacent to the photoelectric converter 120) may have irregularities. However, the present invention is not limited thereto and various modifications are possible.

The second electrode 130 is positioned on the photoelectric converter 120 so that the first electrode 110 and the second electrode 130 are positioned with the photoelectric converter 120 interposed therebetween. Since the second electrode 130 is not a portion to which light is incident, the second electrode 130 may be made of a material (eg, a metal) having excellent electrical conductivity even with low light transmittance. For example, the second electrode 130 may be made of a material such as silver (Ag) or aluminum (Al). The second electrode 130 may be electrically connected to the photoelectric converter 120 to collect electrons or holes (for example, electrons) generated by light and transmit them to the outside.

The photoelectric conversion unit 120 positioned between the first electrode 110 and the second electrode 130 is a portion caused by photoelectric conversion using the incident light. In the present embodiment, the photoelectric converter 120 includes a plurality of photoelectric converters, and is limited to have different thicknesses according to the wavelength of incident light. This will be explained in more detail.

The photoelectric converter 120 may include a first photoelectric converter 121 formed on the first electrode 110 and a first photoelectric converter 121 (that is, the first photoelectric converter 121 and the second electrode). And a second photoelectric converter 123 formed between the electrodes 120. The first photoelectric conversion unit 121 is a first p-type semiconductor layer 121p, a first i-type semiconductor layer 121i, and a first n-type that are sequentially formed to have a pin structure from the light receiving surface of the substrate 100. The semiconductor layer 121n may be included. Similarly, the second photoelectric converter 123 may include a second p-type semiconductor layer 123p, a second i-type semiconductor layer 123i, and a second n-type formed sequentially on the first photoelectric converter 121. The semiconductor layer 123n may be included.

In the present exemplary embodiment, the photoelectric converter 120 repeats the p-i-n structure from the light receiving surface of the substrate 100 as an example. However, the present invention is not limited thereto. Therefore, the structure of n-i-p may be repeated in the photoelectric conversion unit 120 from the light receiving surface of the substrate 100.

The first i-type semiconductor layer 121i absorbs light of a first wavelength band (for example, a short wavelength band of 300 to 700 nm) to generate electrons and holes as carriers, and the second i-type semiconductor layer 123i has a first wavelength band. Electrons and holes can be generated by absorbing light in a larger second wavelength band (eg, a long wavelength band of 500 to 1100 nm). As described above, in the present exemplary embodiment, carriers may be generated using both light of short wavelength band and long wavelength band, thereby improving efficiency of the thin film solar cell 10.

For example, the first i-type semiconductor layer 121i may be formed of an amorphous silicon (a-Si) material, and the second i-type semiconductor layer 123i may be made of a microcrystalline silicon (uc-Si) material. Can be. The first p-type semiconductor layer 121p, the first n-type semiconductor layer 121n, the second p-type semiconductor layer 123p, and the second n-type semiconductor layer 123n may be formed of various materials. For example, the first p-type semiconductor layer 121p and the second p-type semiconductor layer 123p may be formed of amorphous silicon carbide (a-SiC) material to function as a window layer. The first n-type semiconductor layer 121n and the second n-type semiconductor layer 123n may be made of microcrystalline silicon (uc-Si) material. However, the present invention is not limited thereto.

In this embodiment, the thickness of the first and second photoelectric converters 121 and 123 is limited according to the region where the thin film solar cell 10 is actually used to maximize the efficiency of the thin film solar cell 10.

In the conventional thin film solar cell, the current is generated in the first photoelectric converter and the first photoelectric converter based on the case where the atmospheric mass index (AM) is 1.5 and shipped with a high power generation output. That is, as shown in Fig. 2, the quantum efficiency (dashed line in Fig. 2) in light of 300 to 700 nm short wavelength band and the quantum efficiency (dashed line in Fig. 2) by light of long wavelength band of 500 to 1100 nm have excellent values. In addition, the overall quantum efficiency (solid line in FIG. 2) may also have an excellent value. In this case, the thickness of the first i-type semiconductor layer is about 200 to 250 nm, and the thickness of the second i-type semiconductor layer is about 800 to 1200 nm. However, thin-film solar cells are not placed in an environment with an air mass index of 1.5, but in the environment of each region. For example, in areas with a lot of clouds or fog, the light in the short wavelengths is relatively low and the light in the long wavelengths is more than in the case where the atmospheric mass index is 1.5. As another example, in the sunbelt region, where there is a lot of direct sunlight, there are relatively more light in the short wavelength band and less light in the long wavelength band than when the atmospheric mass index is 1.5. Therefore, when the thin film solar cell is actually used, the efficiency of the thin film solar cell is lower than expected due to the difference in environment.

Accordingly, in the present embodiment, the thin film solar cell 10 optimized in each case is divided into regions having more short wavelengths and regions having more long wavelengths. First, the thin film solar cell 10 used in a region where the light of the long wavelength is relatively high and the light of the short wavelength is relatively small is described. The battery 10 will be described.

First, in a region where the light of the long wavelength band is relatively high and the light of the short wavelength band is relatively small, the thickness T1 of the first i-type semiconductor layer 121i of the thin film solar cell 10 that absorbs the light of the short wavelength band is larger than that of the conventional art. can do. Then, a relatively small amount of short wavelength light can be absorbed more efficiently, so that both short wavelength light and long wavelength light can be efficiently used. At this time, when the amount of current by the second photoelectric converter 123 is 100%, the amount of current by the first photoelectric converter 121 may be 110 to 130%. To this end, the thickness T1 of the first i-type semiconductor layer 121i may be 280 to 330 nm, and the thickness T2 of the second i-type semiconductor layer 123i may be 800 to 1200 nm. Then, as shown in FIG. 3, the thin film solar cell 10 can use both light of a short wavelength band and light of a long wavelength band efficiently, and can have sufficient amount of electric current. Accordingly, the light efficiency of the thin film solar cell 10 may be maximized in a region where the light of the long wavelength band is relatively large and the light of the short wavelength band is relatively small.

On the other hand, in the region where the light of the short wavelength band is relatively high and the light of the long wavelength band is relatively small, the thickness T2 of the second i-type semiconductor layer 123i of the thin film solar cell 10 that absorbs the light of the long wavelength band is larger than before. can do. Then, a relatively small amount of long wavelength light can be absorbed more efficiently, so that light of a short wavelength band and light of a long wavelength band can be efficiently used. Accordingly, when the amount of current by the first photoelectric converter 121 is 100%, the amount of current by the second photoelectric converter 123 may be 110 to 130%. To this end, the thickness T1 of the first i-type semiconductor layer 121i may be 200 to 250 nm, and the thickness T2 of the second i-type semiconductor layer 123i may be 1500 to 2000 nm. Then, as shown in FIG. 4, the thin film solar cell 10 can efficiently use both light of a short wavelength band and light of a long wavelength band, and thus can have a sufficient amount of current. Accordingly, the efficiency of the thin film solar cell 10 may be maximized in a region where the light of the short wavelength band is relatively large and the light of the long wavelength band is relatively small.

The photoelectric converter 120 may be formed by chemical vapor deposition (CVD), such as plasma chemical vapor deposition (PECVD).

In the first photoelectric converter 121, when light is incident, the first p-type semiconductor layer 121p and the second n-type semiconductor layer 121n having a relatively high doping concentration inside the first i-type semiconductor layer 121i. By depletion is formed, thereby an electric field can be formed. Due to the photovoltaic effect, electrons and holes generated in the first i-type semiconductor layer 121i as the light absorbing layer are separated by the contact potential difference and moved in different directions. For example, holes move toward the first electrode 110 and electrons move toward the second electrode 130. Similarly, holes generated by the second photoelectric converter 123 move toward the first electrode 110 and electrons move toward the second electrode 130. This generates power.

In the drawings and the above description, the case where there is only one photoelectric conversion unit 120 is illustrated, but a plurality of photoelectric conversion units 120 may be electrically connected to each other on a plane by scribing or patterning. The technology for forming the plurality of photoelectric converters 120 on a plane by scribing, patterning, etc. may be applied to a known technique, and thus detailed descriptions and drawings thereof will be omitted. This is the same in the embodiment related to FIG. 5 described below.

Hereinafter, a thin film solar cell according to another exemplary embodiment of the present invention will be described in more detail with reference to FIG. 5. Hereinafter, the description of the substrate 100, the first electrode 110, and the second electrode 130 having the same or very similar configuration as those of the above-described embodiment will be omitted, and only the photoelectric converter 220 will be described in detail. .

5 is a cross-sectional view of a thin film solar cell according to another embodiment of the present invention.

Referring to FIG. 5, the photoelectric converter 220 according to the present exemplary embodiment may include a first photoelectric converter 221, a second photoelectric converter 223, and a second photoelectric converter 223, which are sequentially formed on the first electrode 110. The third photoelectric converter 235 is included. The first photoelectric converter 221 may include the first p-type semiconductor layer 221p, the first i-type semiconductor layer 221i, and the first n-type semiconductor layer 221n which are sequentially formed on the first electrode 110. It may include. Similarly, the second photoelectric converter 223 includes the second p-type semiconductor layer 223p, the second i-type semiconductor layer 223i, and the second n-type that are sequentially formed on the first photoelectric converter 221. The semiconductor layer 223n may be included. Similarly, the third photoelectric converter 225 may include a third p-type semiconductor layer 225p, a third i-type semiconductor layer 225i, and a third n-type sequentially formed on the second photoelectric converter 223. The semiconductor layer 225n may be included.

In the present exemplary embodiment, the p-i-n structure is repeated in the photoelectric conversion unit 220 from the light receiving surface of the substrate 100, but the present invention is not limited thereto. Therefore, the structure of n-i-p may be repeated in the photoelectric conversion unit 220 from the light receiving surface of the substrate 100.

The first i-type semiconductor layer 221i may absorb light in a first wavelength band (for example, a short wavelength band of 300 to 700 nm) to generate electrons and holes as carriers, and the second i-type semiconductor layer 223i may By absorbing light in a second wavelength band (for example, a medium wavelength band of 400 to 900 nm), electrons and holes serving as carriers can be generated, and the third i-type semiconductor layer 225i has a third wavelength band (for example, 500 to 1100 nm). Can absorb light of a long wavelength band) to generate electrons and holes as carriers. Here, the short wavelength band, the medium wavelength band, and the long wavelength band may be divided around the wavelength when the quantum efficiency is the highest. That is, when the wavelength at the highest quantum efficiency is the shortest, the wavelength at the highest quantum efficiency is the longest, and the wavelength at the highest quantum efficiency is between the short and the longest. It can be said to be a medium wavelength band.

As described above, in the present embodiment, carriers can be generated using all of the light of the short wavelength band, the medium wavelength band, and the long wavelength band, thereby improving the efficiency of the thin film solar cell 12.

For example, the first i-type semiconductor layer 221i may be made of an amorphous silicon material, and the second i-type semiconductor layer 223i may be made of amorphous silicon germanium (a-Si: Ge) or microcrystalline silicon material. . The third i-type semiconductor layer 235i may be made of microcrystalline silicon or microcrystalline silicon germanium.

The first p-type semiconductor layer 221p, the first n-type semiconductor layer 221n, the second p-type semiconductor layer 223p, the second n-type semiconductor layer 223n, and the third p-type semiconductor layer 225p. The third n-type semiconductor layer 225n may be formed of various materials. For example, the first p-type semiconductor layer 221p and the second p-type semiconductor layer 223p may be made of amorphous silicon carbide to function as a window layer. The first n-type semiconductor layer 221n and the second n-type semiconductor layer 223n may be made of a microcrystalline silicon material. The third p-type semiconductor layer 225p and the third n-type semiconductor layer 225n may be made of a microcrystalline silicon material. However, the present invention is not limited thereto.

In the present embodiment, the thin film solar cell 12 is optimized in each case by dividing the light having a shorter wavelength band and the light having a longer wavelength band. First, the thin film solar cell 12 in a region where the light of the long wavelength band is relatively high and the light of the short wavelength band is relatively small is described. Then, the thin film solar cell 12 of the region where the light of the short wavelength band is relatively large and the light of the long wavelength band is relatively small. Explain.

First, in a region where the light of the long wavelength band is relatively large and the light of the short wavelength band is relatively small, the thickness T1 of the first i-type semiconductor layer 221i of the thin film solar cell 12 that absorbs the light of the short wavelength band is larger than that of the prior art. can do. Then, a relatively small amount of short wavelength light can be absorbed more efficiently, so that both short wavelength light and long wavelength light can be efficiently used. Accordingly, when the amount of current by the second photoelectric converter 223 or the third photoelectric converter 225 is 100%, the amount of current by the first photoelectric converter 221 may be 110 to 130%. have. To this end, the thickness T10 of the first i-type semiconductor layer 221i may be 150 to 200 nm, and the thickness T20 of the second i-type semiconductor layer 223i may be 150 to 200 nm. The thickness T30 of the third i-type semiconductor layer 225i may be 2200 to 2700 nm. Then, as shown in FIG. 6, the thin film solar cell 12 can have a high quantum efficiency and have a sufficient amount of current in both short wavelength light and long wavelength light. Accordingly, the efficiency of the thin film solar cell 12 can be maximized in a region where the light of the long wavelength band is relatively large and the light of the short wavelength band is relatively small.

On the other hand, in the region where the light of the short wavelength band is relatively high and the light of the long wavelength band is relatively small, the thickness T2 of the second i-type semiconductor layer 223i of the thin film solar cell 12 that absorbs the light of the long wavelength band is larger than the conventional one. can do. Then, a relatively small amount of long wavelength light can be absorbed more efficiently, so that both short wavelength light and long wavelength light can be efficiently used. Accordingly, when the amount of current by the first photoelectric converter 221 or the second photoelectric converter 223 is 100%, the amount of current by the third photoelectric converter 225 may be 110 to 130%. have. To this end, the thickness T10 of the first i-type semiconductor layer 221i may be 80 to 120 nm, and the thickness T20 of the second i-type semiconductor layer 223i may be 150 to 200 nm. The thickness T30 of the third i-type semiconductor layer 225i may be 3000 to 3500 nm. Then, as illustrated in FIG. 7, the thin film solar cell 12 may have a high quantum efficiency and may have a sufficient amount of current in both short wavelength light and long wavelength light. Accordingly, the efficiency of the thin film solar cell 12 can be maximized in a region where the light of the short wavelength band is relatively high and the light of the long wavelength band is relatively small.

As described above, according to the present embodiment, a thin film solar cell suitable for each region may be provided to maximize the efficiency and output of the thin film solar cell, thereby increasing power generation. For example, the crystalline silicon solar cell has a higher output than the thin film solar cell because the silicon wafer is used, but has a lower output than the thin film solar cell in the sunbelt region due to the low band gap and temperature coefficient. In such a sunbelt region, by using a thin film solar cell having a structure capable of absorbing long wavelengths of light more efficiently, power generation can be maximized by maximizing output and efficiency.

Features, structures, effects and the like according to the above-described embodiments are included in at least one embodiment of the present invention, and the present invention is not limited to only one embodiment. Further, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified in other embodiments by those skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

10, 12: thin film solar cell
100: substrate
110: first electrode
120, 220: photoelectric conversion unit
130: second electrode

Claims (12)

Board;
A first electrode formed on the substrate;
A plurality of photoelectric conversion parts formed on the first electrode; And
A second electrode formed on the photoelectric conversion unit,
/ RTI >
The plurality of photoelectric conversion unit,
A first photoelectric conversion unit formed on the first electrode to perform a photoelectric conversion operation using light of a first wavelength band, and including a first p-type semiconductor layer, a first i-type semiconductor layer, and a first n-type semiconductor layer ; And
A photoelectric conversion function using light of a second wavelength band formed on the first photoelectric conversion part and larger than the first wavelength band, and having a second p-type semiconductor layer, a second i-type semiconductor layer, and a second n-type semiconductor layer Including a second photoelectric conversion unit including,
The first i-type semiconductor layer and the second i-type semiconductor layer have a different thickness in consideration of the amount of light in the first wavelength band and the second wavelength band in each region. The method of claim 1,
In a region where the light of the second wavelength band is larger than the light of the first wavelength band, the first i-type semiconductor layer has a thickness of 280 nm to 330 nm, and the thickness of the second i-type semiconductor layer is 800 nm to 1200 nm. . 3. The method of claim 2,
The thin film solar cell whose amount of current by a said 1st photoelectric conversion part is 110 to 130% when the amount of current by a said 2nd photoelectric conversion part is 100%. The method of claim 1,
The plurality of photoelectric conversion unit,
In the region where the light of the first wavelength band is larger than the light of the second wavelength band, the thin film solar cell having a thickness of the first i-type semiconductor layer is 200 nm to 250 nm and the thickness of the second i-type semiconductor layer is 1500 nm to 2000 nm. . 5. The method of claim 4,
A thin film solar cell having a current amount of 110 to 130% at the second photoelectric conversion part when the amount of current by the first photoelectric conversion part is 100%. The method of claim 1,
The first i-type semiconductor layer includes amorphous silicon,
The second i-type semiconductor layer is a thin film solar cell containing microcrystalline silicon. Board;
A first electrode formed on the substrate;
A plurality of photoelectric conversion parts formed on the first electrode; And
A second electrode formed on the photoelectric conversion unit,
/ RTI >
The plurality of photoelectric conversion unit,
A first photoelectric conversion unit formed on the first electrode to perform a photoelectric conversion operation using light of a first wavelength band, and including a first p-type semiconductor layer, a first i-type semiconductor layer, and a first n-type semiconductor layer ;
Forming a second p-type semiconductor layer, a second i-type semiconductor layer, and a second n-type semiconductor layer on the first photoelectric conversion part by using light of a second wavelength band larger than the first wavelength band. A second photoelectric conversion unit comprising; And
A third p-type semiconductor layer, a third i-type semiconductor layer, and a third n-type semiconductor layer formed on the second photoelectric conversion part and performing photoelectric conversion using light in a third wavelength band larger than the second wavelength band. Third photoelectric conversion unit including a
Lt; / RTI >
The first i-type semiconductor layer, the second i-type semiconductor layer, and the third i-type semiconductor layer are different from each other in consideration of the amount of light in the first wavelength band, the second wavelength band, and the third wavelength band in each region. Thin film solar cell with thickness. 8. The method of claim 7,
In an area where the light of the third wavelength band is larger than the light of the first wavelength band, the thickness of the first i-type semiconductor layer is 150 nm to 200 nm, the thickness of the second i-type semiconductor layer is 150 nm to 200 nm, A thin film solar cell having a thickness of a 3 i-type semiconductor layer is 2200 nm to 2700 nm. 9. The method of claim 8,
The thin film solar cell whose amount of current by a said 1st photoelectric conversion part is 110 to 130% when the amount of electric current by a said 2nd photoelectric conversion part or a said 3rd photoelectric conversion part is 100%. 8. The method of claim 7,
In a region where the light of the first wavelength band is larger than the light of the third wavelength band, the thickness of the first i-type semiconductor layer is 80 nm to 120 nm, the thickness of the second i-type semiconductor layer is 150 nm to 200 nm, The thin film solar cell whose thickness of a 3i type semiconductor layer is 3000 nm-3500 nm. 11. The method of claim 10,
The thin film solar cell whose amount of current by a said 3rd photoelectric conversion part is 110 to 130% when the amount of electric current by a said 1st photoelectric conversion part or a said 2nd photoelectric conversion part is 100%. 8. The method of claim 7,
The first i-type semiconductor layer includes an amorphous silicon material,
The second i-type semiconductor layer includes an amorphous silicon germanium or microcrystalline silicon material,
The i-type semiconductor layer is a thin film solar cell comprising a microcrystalline silicon or microcrystalline silicon germanium material.

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