KR102052507B1 - Thin film solar cell module - Google Patents

Abstract

The present invention relates to a thin film solar cell module.
One example of a solar cell module according to the present invention includes a substrate; And a plurality of cells formed on the substrate and having a first electrode positioned on the substrate, a photoelectric conversion portion positioned on the first electrode, a rear reflective layer positioned on the photoelectric conversion portion, and a second electrode positioned on the rear reflective layer. Wherein the plurality of cells comprises at least one first cell positioned in an edge region of the substrate and at least one second cell positioned in a central region of the substrate, and at least one first positioned in an edge region of the substrate. The average oxygen content of the back reflection layer included in the cell is higher than the average oxygen content of the back reflection layer included in the at least one second cell positioned in the central region of the substrate, and each of the photoelectric conversion units included in the plurality of cells includes a plurality of photoelectric In the case of including a conversion layer, each of the plurality of cells further includes an intermediate reflective layer between the plurality of photoelectric conversion layers, respectively, The oxygen content of the intermediate reflective layer included in the first cell is smaller than the average oxygen content of the intermediate reflective layer included in the second cell located in the center region of the substrate.

Description

Thin Film Solar Cell Module {THIN FILM SOLAR CELL MODULE}

The present invention relates to a thin film solar cell module.

With the recent prediction of the depletion of existing energy resources such as oil and coal, the interest in alternative energy to replace them is increasing, and solar cells producing electric energy from solar energy are attracting attention.

Single crystal bulk silicon using silicon wafers is currently commercialized, but due to high manufacturing costs, active utilization is not possible.

In order to solve this problem, researches on thin film solar cells have been actively conducted in recent years. Such thin film solar cells have attracted a lot of attention as a technology capable of manufacturing large-area solar cell modules at low cost.

The technical problem of the present invention is to provide a thin film solar cell module with improved efficiency.

One example of a solar cell module according to the present invention includes a substrate; And a plurality of cells formed on the substrate and having a first electrode positioned on the substrate, a photoelectric conversion portion positioned on the first electrode, a rear reflective layer positioned on the photoelectric conversion portion, and a second electrode positioned on the rear reflective layer. Wherein the plurality of cells comprises at least one first cell positioned in an edge region of the substrate and at least one second cell positioned in a central region of the substrate, and at least one first positioned in an edge region of the substrate. The average oxygen content of the back reflection layer included in the cell is higher than the average oxygen content of the back reflection layer included in the at least one second cell located in the central region of the substrate.

Here, the oxygen content of the back reflection layer included in the plurality of cells may increase stepwise or gradually as the process proceeds from the center region to the edge region of the substrate.

In this case, the average oxygen content of the back reflection layer included in the at least one first cell positioned in the edge region of the substrate is 1 at% than the average oxygen content of the back reflection layer included in the at least one second cell positioned in the central region of the substrate. p (atomic percent) to 25at% p can be many.

In addition, the at least one first cell is disposed long in a stripe shape on the substrate, and the average oxygen content of the back reflection layer included in the at least one first cell may vary in the length direction of the at least one first cell.

In one example, the oxygen content of the back reflecting layer at both ends of the at least one first cell may be greater than the oxygen content of the back reflecting layer in the central region of the at least one first cell, along the longitudinal direction of the at least one first cell. The oxygen content contained in the rear reflective layer of the at least one first cell may increase stepwise or gradually toward both ends in the central region of the at least one first cell.

In addition, the at least one second cell is disposed long on the substrate in the form of a stripe, and the average oxygen content of the back reflection layer included in the at least one second cell may vary in the length direction of the at least one second cell.

Specifically, the oxygen content of the rear reflective layer at both ends of the at least one second cell may be greater than the oxygen content of the rear reflective layer in the central region of the at least one second cell, along the longitudinal direction of the at least one second cell. The oxygen content contained in the rear reflective layer of the at least one second cell may increase stepwise or gradually toward both ends in the central region of the at least one second cell.

In this case, each photoelectric conversion unit included in the plurality of cells may include a first semiconductor layer including impurities of a first conductivity type, a second semiconductor layer including impurities of a second conductivity type opposite to impurities of the first conductivity type, And at least one photoelectric conversion layer including an intrinsic semiconductor layer positioned between the first semiconductor layer and the second semiconductor layer.

In addition, each back reflecting layer included in the plurality of cells includes fine crystalline silicon oxide (mc-SiOx) doped with impurities of the first conductivity type or the second conductivity type or zinc oxide (ZnO: Al) containing aluminum. can do.

In addition, another example of the thin film solar cell module according to the present invention; And a plurality of cells formed on the substrate, the plurality of cells including a first electrode on the substrate, a photoelectric conversion unit on the first electrode, and a second electrode on the photoelectric conversion unit. At least one first cell positioned in an edge region and at least one second cell positioned in a central region of the substrate, wherein each of the photoelectric conversion units included in the at least one first cell and the second cell includes: A photovoltaic conversion layer, each of the at least one first cell and the second cell each further including an intermediate reflective layer between the plurality of photoelectric conversion layers, the intermediate reflective layer being included in the first cell positioned at the edge region of the substrate. The oxygen content is smaller than the average oxygen content of the intermediate reflective layer included in the second cell located in the center region of the substrate.

Here, the oxygen content of the intermediate reflective layer included in the plurality of cells may decrease gradually or gradually as the process proceeds from the center region to the edge region of the substrate.

In addition, the oxygen content of the intermediate reflective layer included in the at least one first cell positioned in the edge region of the substrate is 1 at% p than the average oxygen content of the intermediate reflective layer included in the at least one second cell positioned in the central region of the substrate. Can be as small as ~ 25at% p.

In addition, the at least one first cell is disposed long in a stripe shape on the substrate, and the oxygen content of the intermediate reflective layer included in the at least one first cell may vary in the length direction of the at least one first cell.

Specifically, the oxygen content at both ends of the intermediate reflective layer included in the at least one first cell may be less than the oxygen content in the central region of the intermediate reflective layer included in the at least one first cell, and at least one first The oxygen content of the intermediate reflective layer included in the at least one first cell may decrease in steps or gradually from the central region of the intermediate reflective layer included in the at least one first cell along the length direction of the cell.

In addition, the at least one second cell is disposed long in a stripe shape on the substrate, and the average oxygen content of the intermediate reflective layer included in the at least one second cell may vary in the length direction of the at least one second cell.

For example, the oxygen content at both ends of the intermediate reflective layer included in the at least one second cell may be less than the oxygen content in the central region of the intermediate reflective layer included in the at least one second cell, and at least one second The average oxygen content of the intermediate reflective layer included in the at least one second cell may decrease in steps or gradually from the central region of the intermediate reflective layer included in the at least one second cell along the length direction of the cell.

In addition, each of the photoelectric conversion parts included in the plurality of cells includes a first photoelectric conversion layer positioned on the first electrode and a second photoelectric conversion layer positioned on the first photoelectric conversion layer, and the intermediate reflective layer included in the plurality of cells. May be positioned between the first photoelectric conversion layer and the second photoelectric conversion layer.

Each of the photoelectric conversion units included in the plurality of cells may include a first photoelectric conversion layer positioned on the first electrode, a second photoelectric conversion layer positioned on the first photoelectric conversion layer, and a third photoelectric conversion layer located on the second photoelectric conversion layer. The intermediate reflective layer including the photoelectric conversion layer and included in the plurality of cells may be positioned between the second photoelectric conversion layer and the third photoelectric conversion layer.

In addition, each intermediate reflective layer included in the plurality of cells may include aluminum oxide-containing zinc oxide (ZnO: Al) or fine crystalline silicon oxide (mc-SiOx).

In this case, the oxygen content at the upper and lower boundary surfaces of the intermediate reflective layer in contact with the photoelectric conversion layer in the intermediate reflective layer included in the plurality of cells may be smaller than the oxygen content in the middle portion of the intermediate reflective layer.

According to this feature, the oxygen content of the intermediate reflection layer or the rear reflection layer located in the center region of the substrate is different from that of the intermediate reflection layer or the rear reflection layer located in the edge region of the substrate, thereby improving the efficiency of the thin film solar cell module. have.

1 is a view for explaining an example of a thin film solar cell module according to the present invention.
FIG. 2 is a view for explaining a side structure of a thin film solar cell module taken along the line II-I in FIG. 1.
FIG. 3 is a diagram for describing a detailed structure of a thin film solar cell taken along a line II-II in FIG. 2.
4 is an example of an equivalent circuit obtained by analyzing a thin film solar cell module.
5 is a diagram for explaining the relationship between the oxygen content and the refractive index contained in the back reflection layer and the intermediate reflection layer.
6 and 7 illustrate an example in which the oxygen containing fragrance of the rear reflection layer is adjusted according to the position of the substrate when the photoelectric conversion unit of the thin film solar cell module illustrated in FIG. 1 includes one pin photoelectric conversion layer.
8 to 9 are diagrams for explaining an example in which the oxygen content of the intermediate reflective layer along the region of the substrate is adjusted when the photoelectric conversion layer has two double junction structures.
FIG. 10 is a view for explaining in detail the vertical oxygen content of the intermediate reflective layer included in the first cell and the second cell in FIG. 8.
11 is a view for explaining an example in which the oxygen content of the intermediate reflective layer along the region of the substrate is adjusted when the photoelectric conversion layer has three triple junction structures.
12 to 14 illustrate examples and effects of applications in which the oxygen content of the second intermediate reflective layer and the rear reflective layer is different depending on the area of the substrate when the photoelectric conversion unit of the thin film solar cell module of FIG. 11 has a triple junction structure. It is a figure for demonstrating.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. When a portion of a layer, film, region, plate, etc. is said to be "on top" of another part, this includes not only when the other part is "right over" but also when there is another part in the middle. On the contrary, when a part is "just above" another part, there is no other part in the middle. In addition, when a part is formed “overall” on another part, it means that it is not only formed on the entire surface (or front) of the other part but also on the edge part.

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

1 is a view for explaining an example of a thin film solar cell module according to the present invention, Figure 2 is a view for explaining the side structure of the thin film solar cell module according to the line I-I in Figure 1, Figure 3 It is a figure for demonstrating the detailed structure of the thin film solar cell along the II-II line in 2, and FIG. 4 is an example of the equivalent circuit which analyzed the thin film solar cell module.

As shown in FIG. 1, one example of the thin film solar cell module according to the present invention may be formed by arranging a plurality of cells EC1 to CC2 to the substrate 100.

Large-area thin film solar cell modules are generally distributed in the market in sizes of 1.1 × 1.3 ㎡, 1.1 × 1.4 ㎡, 2.2 × 2.6㎡, and 1.1 × 1.3 ㎡ and 1.1 × 1.4 ㎡ thin film solar module It includes a cell.

Here, in the region S1 in which the plurality of cells EC1 to CC to EC2 are not disposed in the portion on the substrate 100, the ineffective region in which the plurality of cells EC1 to CC to EC2 are not disposed and does not cause photoelectric conversion is present. This may be an edge removal region, and the region S2 in which the plurality of cells EC1 to CC to EC2 are disposed may be an effective region that causes photoelectric conversion. Here, each of these cells EC1 to CC to EC2 has a solar cell structure.

That is, as illustrated in FIGS. 2 and 3, each of the cells EC1 to CC to EC2 includes the substrate 100, the first electrode 110, the photoelectric conversion unit PV, the rear reflective layer 130, and the like. It may include a second electrode 140.

The present invention is to improve the overall photoelectric efficiency of the thin film solar cell module having a large area by controlling the characteristics of the first cell (EC1, EC2) and the second cell (CC) of the plurality of cells (EC1 ~ CC ~ EC2). In the present invention, the first cells EC1 and EC2 are edge regions of the substrate 100, that is, edge removing regions of the substrate 100, among the effective regions in which the plurality of cells EC1 to CC to EC2 are disposed. Define at least one or more cells from the outermost cell located closest to the second cell CC, and define the at least one or more cells among the cells located in the center region between the first cells EC1 and EC2 disposed in the edge region. do. Therefore, the second cell CC may be all cells except for the first cells EC1 and EC2.

Here, the substrate 100 functions to support other functional layers on the substrate 100. In addition, the substrate 100 may be made of a substantially transparent material, for example, glass or plastic material, in order for the incident light to reach the photoelectric conversion part PV more effectively.

The first electrode 110 may be disposed on the substrate 100 and may include a material that is substantially transparent and electrically conductive to increase transmittance of incident light. For example, the first electrode 110 may have indium tin oxide (ITO) or tin oxide (SnO _2, etc.) in order to have high light transmittance and high electrical conductivity so that most of the light can pass through. , AgO, ZnO- (Ga ₂ O ₃ or Al ₂ O ₃ ), fluorine tin oxide (FTO), zinc oxide with aluminum (ZnO: Al, AZO), zinc oxide with boron ( ZnO: B, BZO) and mixtures thereof.

The first electrode 110 may be electrically connected to the photoelectric conversion unit PV. Accordingly, the first electrode 110 may collect and output one of the carriers generated by the incident light, for example, holes.

In addition, a plurality of irregularities having a random pyramid structure may be formed on the upper surface of the first electrode 110. That is, the first electrode 110 has a texturing surface. As such, when the surface of the first electrode 110 is textured, it is possible to reduce reflection of incident light and increase light absorption, thereby improving efficiency of the solar cell 10.

The photoelectric conversion unit PV is positioned on the first electrode 110 and functions to generate electric power from light incident from the outside.

The photoelectric conversion part PV may include a first semiconductor layer, an intrinsic semiconductor layer, and a second semiconductor layer, and the first semiconductor layer may include impurities of a first conductivity type, for example, 3 in silicon (Si). Impurity of p type, such as impurity of a valent element, the second semiconductor layer is located on the first semiconductor layer, and the impurity of the second conductivity type in silicon (Si) opposite to the impurity of the first conductivity type, For example, impurities of pentavalent elements may contain the same n-type impurities.

In addition, the intrinsic semiconductor layer PV-i may be positioned between the first semiconductor layer and the second semiconductor layer, and may be formed of silicon (Si) material, and may include impurities of the first and second conductivity types described above. It does not contain. However, other impurities, for example, impurities such as germanium (Ge) may be contained.

Hereinafter, the case where the first semiconductor layer is a p-type semiconductor layer (PV-p) containing p-type impurities and the second semiconductor layer is an n-type semiconductor layer (PV-n) containing n-type impurities are taken as an example. However, unlike this, the first semiconductor layer is an n-type semiconductor layer (PV-n) containing n-type impurities, and the second semiconductor layer is a p-type semiconductor layer (PV-p) containing p-type impurities. It may be.

For example, as shown in FIG. 3, the photoelectric conversion unit PV has a pin structure, that is, a p-type semiconductor layer PV-p and an intrinsic (i-type) semiconductor layer PV- from an incident surface of the substrate 100. i), the n-type semiconductor layer PV-n may be stacked sequentially. Alternatively, however, the photoelectric conversion unit PV may be formed in a structure such as n-i-p.

In more detail, the p-type semiconductor layer PV-p may be formed by using a gas containing an impurity of a trivalent element such as boron, gallium, indium, etc. in a source gas containing silicon (Si).

The n-type semiconductor layer PV-n may be formed by using a gas containing impurities of pentavalent elements such as phosphorus (P), arsenic (As), and antimony (Sb) in a source gas containing silicon.

The intrinsic (i) semiconductor layer PV-i may reduce the recombination rate of the carrier and absorb light. The intrinsic semiconductor layer PV-i may absorb incident light and generate carriers such as electrons and holes.

This intrinsic semiconductor layer (PV-i) is an amorphous silicon material, such as hydrogenated amorphous silicon (a-Si: H) or microcrystalline silicon (mc-Si) material, such as hydrogenated microcrystals Silicon (mc-Si: H). In addition, germanium (Ge) may be contained in such a material.

The doped layers such as the p-type semiconductor layer PV-p and the n-type semiconductor layer PV-n of the photoelectric conversion unit PV may form a pn junction with the intrinsic semiconductor layer PV-i interposed therebetween. Can be. That is, the photoelectric conversion unit PV may be disposed between the n-type impurity doped layer, that is, the n-type semiconductor layer PV-n and the p-type impurity doped layer, that is, the p-type semiconductor layer PV-p.

The photoelectric conversion unit PV may be formed by chemical vapor deposition (CVD), such as plasma enhanced chemical vapor deposition (PECVD).

In FIG. 3, only one photoelectric conversion layer including a p-i-n semiconductor layer in the photoelectric conversion unit PV is described as an example. Alternatively, a plurality of photoelectric conversion layers including a p-i-n semiconductor layer may be provided. That is, the photoelectric conversion unit PV may have two or three photoelectric conversion layers including the p-i-n semiconductor layer. When there are two photoelectric conversion layers provided with a p-i-n semiconductor layer, it has a double junction structure, and when there are three, it has a triple junction structure.

As described above, when the photoelectric conversion layer is two or three, the back reflection layer 130 may be omitted, unlike when the photoelectric conversion layer is one.

In addition, when there are two or three photoelectric conversion layers, an intermediate reflective layer 120 (not shown in FIG. 8 or less) may be further formed between the plurality of photoelectric conversion layers. As such, the intermediate reflective layer 120 formed between the plurality of photoelectric conversion layers may include zinc oxide (ZnO: Al) containing aluminum or impurities of the first conductive type or the second conductive type, that is, p-type impurities or n-type. May include fine crystalline silicon oxide (mc-SiOx) doped with impurities.

In the present invention, the case where the intermediate reflective layer 120 contains fine crystalline silicon oxide (mc-SiOx), for example, the case of containing an n-type impurity will be described as an example.

The intermediate reflective layer 120 will be described in more detail with reference to FIGS. 8 and 11 below.

In addition, when two or three photoelectric conversion layers are provided, as well as the intermediate reflective layer 120 and the rear reflective layer 130, the efficiency of the thin film solar cell module is further improved. An example in which the rear reflective layer 130 is provided together will be described.

Next, the rear reflective layer 130 is disposed on the photoelectric conversion part PV, and functions to reflect light not absorbed by the photoelectric conversion part PV back to the photoelectric conversion part PV.

The back reflection layer 130 may be formed of zinc oxide (ZnO: Al) containing aluminum or fine crystalline silicon oxide doped with impurities of a first conductive type or a second conductive type, that is, p-type impurities or n-type impurities ( mc-SiOx).

In the present invention, the case in which the back reflection layer 130 includes fine crystalline silicon oxide (mc-SiOx), for example, contains an n-type impurity as an example.

The second electrode 140 may be positioned on the rear reflective layer 130 and may include a metal material having excellent electrical conductivity in order to increase recovery efficiency of power generated by the photoelectric conversion unit PV.

In addition, the second electrode 140 may collect and output one of the carriers generated by the incident light, for example, electrons, which are electrically connected to the photoelectric conversion unit PV.

The second electrode 140 may be formed of a metal layer including at least one material of silver (Ag) or aluminum (Al) having good electrical conductivity, such as the first electrode 110.

In this structure, when light is incident toward the p-type semiconductor layer PV-p, the p-type semiconductor layer PV-p and the n-type semiconductor layer having a relatively high doping concentration inside the intrinsic semiconductor layer PV-i. Depletion is formed by (PV-n), and thus an electric field may be formed. At this time, the light incident from the outside is separated into electrons and holes in the intrinsic semiconductor layer PV-i and moved in different directions. For example, holes may move toward the first electrode 110 through the p-type semiconductor layer PV-p, and electrons may move toward the second electrode 140 through the n-type semiconductor layer PV-n. . In this way power can be produced.

As described above, the plurality of cells EC1 to CC to EC2 including the first cells EC1 and EC2 and the second cell CC may be connected in series with each other. For example, the first electrode 110 of a cell included in one cell is in direct contact with the second electrode 140 of the immediately adjacent cell, and the plurality of cells EC1 to CC to EC2 are in series with each other. Can be connected.

Thus, as shown in FIG. 4, each of the plurality of cells EC1 to CC to EC2 may be interpreted as an equivalent circuit in which a plurality of diodes are connected in series. Therefore, the current generated by each cell of the thin film solar cell module must be uniform so that the overall efficiency of the thin film solar cell module can be best improved.

Specifically, when the thickness, electrical, or optical characteristics of the photoelectric conversion unit PV included in each cell are not uniform in the thin film solar cell module, any one cell, for example, the first cells EC1 and EC2 The current (i _E1 , i _E2 ) generated in may be lower than the current (i _C ) generated in another cell, for example, the second cell (CC), in this case, a plurality of cells (EC1 ~ CC ~ EC2) ) Is connected in series, the lowest current value (i _E1 , i _E2 ) among the current values produced in the plurality of cells (EC1 ~ CC ~ EC2) is output, the output current (finally outputted from the thin film solar cell module ( i _E1 , i _E2 ) can only be lowered.

In particular, as described above, the thin film solar cell module typically has a large area of 1.1 × 1.3 m 2, 1.1 × 1.4 m 2, and 2.2 × 2.6 m 2, so that each p-type semiconductor of the photoelectric conversion unit PV described above can be used. The thickness and electrical and optical characteristics of the layer PV-p, the intrinsic (i-type) semiconductor layer PV-i, and the n-type semiconductor layer PV-n are arranged in the entire region of the substrate 100. It is technically very difficult to form uniformly in each of the cells EC1 to CC to EC2.

Specifically, in the plurality of cells EC1 to CC to EC2 disposed on the substrate 100, the edge region of the substrate 100 is compared to the second cell CC located at the center region of the substrate 100. The electrical and optical characteristics of the photoelectric converters PV of the located first cells EC1 and EC2 are relatively low, so that the photoelectric conversion capability of the first cells EC1 and EC2 is relatively higher than that of the second cell CC. Can be low. Accordingly, the output current of the thin film solar cell module may be relatively lowered.

In addition, when there are a plurality of photoelectric conversion layers of the photoelectric conversion part PV, the number and thickness of the stacked photoelectric conversion layers are relatively larger, and thus, the first cells EC1 and EC2 positioned in the edge region of the substrate 100. The electrical and optical characteristics of the photoelectric conversion layer that is stacked last among the photoelectric conversion units (PV) of the) may be relatively lowered, so that the output current of the thin film solar cell module may be further lowered.

Therefore, in view of such a point, the present invention provides the oxygen contained in the back reflection layer 130 when there is only one photoelectric conversion layer of the photoelectric conversion unit PV included in the plurality of cells EC1 to CC to EC2. The content is formed differently according to the position of the substrate 100, thereby improving the photoelectric conversion capability of the first cells EC1 and EC2, which are relatively inferior to the second cell CC, so that the first cell ( Photoelectric conversion of the first cells EC1, EC2 and the second cell CC so that the magnitudes of the currents I _E1 , i _E2 , i _C output from the EC1, EC2 and the second cell CC are uniform. The ability can be made uniform.

In addition, when there are a plurality of photoelectric conversion layers of the photoelectric conversion unit PV included in the plurality of cells EC1 to CC to EC2, the oxygen content contained in at least one of the rear reflective layer 130 and the intermediate reflective layer 120 is determined. Formed differently according to the position of the substrate 100, the photoelectric conversion capability of the photoelectric conversion layer that is stacked last among the photoelectric conversion units PV of the first cells EC1 and EC2 is improved, so that the first cells EC1 and EC2. ) And the currents i _E1 , i _E2 , i _C output from the second cell CC are uniform, so that the photoelectric conversion capability of the first cells EC1, EC2 and the second cell CC is uniform. It can be done.

Accordingly, the present invention can allow the overall efficiency of the thin film solar cell module to be improved to the best. Hereinafter, the applicable examples according to this will be described in detail.

In the present invention, the oxygen content contained in the back reflective layer 130 or the intermediate reflective layer 120 is adjusted because the oxygen content is closely related to the refractive index of the back reflective layer 130 or the intermediate reflective layer 120.

5 is a diagram for explaining the relationship between the oxygen content and the refractive index contained in the back reflection layer and the intermediate reflection layer.

As shown in FIG. 5, as the oxygen content of the back reflection layer 130 or the intermediate reflection layer 120 increases from 36% to 44%, the refractive index of the back reflection layer 130 or the intermediate reflection layer 120 decreases. You can check it. For reference, in FIG. 5, the oxygen content contained in the back reflective layer 130 or the intermediate reflective layer 120 is an example for explaining the relationship with the refractive index, and the oxygen content contained in the back reflective layer 130 or the intermediate reflective layer 120. May vary.

As described above, by using the relationship between the oxygen content and the refractive index, the present invention uses the oxygen content of the back reflection layer 130 or the intermediate reflection layer 120 positioned at the edge region of the substrate 100 to the center region of the substrate 100. The electrical and optical characteristics of the photoelectric converter PV positioned in the edge region of the substrate 100 may be different from the oxygen content of the rear reflective layer 130 or the intermediate reflective layer 120 positioned in the central region of the substrate 100. The electrical and optical characteristics of the photoelectric conversion unit PV may be uniform.

Accordingly, according to the present invention, at least one current i _E1 , i _E2 output from at least one first cell EC1, EC2 located in the edge region of the substrate 100 is located in the center region of the substrate 100. The current i _C output from one second cell CC can be made substantially the same.

Accordingly, the photoelectric conversion efficiency of the thin film solar cell module can be maximized.

Here, an example in which the oxygen content of the rear reflective layer 130 positioned in the edge region of the substrate 100 is greater than the oxygen content of the rear reflective layer 130 positioned in the central region of the substrate 100 will be described. And FIG. 7.

6 and 7 illustrate an example in which the oxygen content of the rear reflection layer is adjusted according to the position of the substrate when the photoelectric conversion unit of the thin film solar cell module illustrated in FIG. 1 includes one p-i-n photoelectric conversion layer.

In the thin film solar cell module according to the present invention, as shown in FIG. 6, the average oxygen content of the back reflection layer 130 included in the first cells EC1 and EC2 positioned in the edge region of the substrate 100 may be measured. At least one first cell positioned in the edge region of the substrate 100 by controlling to be greater than the average oxygen content of the rear reflective layer 130 included in the at least one second cell CC positioned in the central region of the substrate 100. The refractive index of the rear reflective layer 130 included in the EC1 and EC2 may be lower than the refractive index of the rear reflective layer 130 included in the at least one second cell CC positioned in the central region of the substrate 100. .

Accordingly, as shown in FIG. 6, the rear reflective layer 130 positioned in the edge region of the substrate 100 has a relatively higher amount of light than the rear reflective layer 130 positioned in the central region of the substrate 100. Can reflect.

Therefore, the photoelectric conversion part PV of the first cells EC1 and EC2 having relatively low electrical and optical properties is relatively more than the photoelectric conversion part PV of the second cell CC having good electrical and optical properties. It can absorb more light. Accordingly, more light is absorbed in the first cells EC1 and EC2, thereby compensating for the photoelectric conversion capability of the relatively lower first cells EC1 and EC2.

Therefore, the currents i _E1 and i _E2 generated by the photoelectric converters PV of the first cells EC1 and EC2 are generated by the photoelectric converters PV of the second cell CC i. _It can be almost the same as _C ), and can further improve the photoelectric conversion efficiency of the thin film solar cell module.

Here, the average oxygen content of the back reflection layer 130 included in the at least one first cell EC1, EC2 located in the edge region of the substrate 100 may be at least one agent located in the central region of the substrate 100. The at least one at% p to 25at% p may be greater than the average oxygen content of the back reflective layer 130 included in the two cells CC.

For example, the rear reflective layers 130 of the first cells EC1 and EC2 and the second cell CC include fine crystalline silicon oxide (n-mc-SiOx) doped with n-type impurities. When the oxygen content of the back reflective layer 130 of the cell CC is 30 at% (atomic percent), for example, the oxygen content of the back reflective layer 130 of the first cells EC1 and EC2 is 31 at% to 55 at. It can be determined within the range of%. (Where at% means atomic percent, and the oxygen content of the back reflection layer 130 including n-mc-SiOx is X at% means that oxygen is 100 when the total number of materials of n-mc-SiOx is 100 atoms). It means that the number of atoms O occupies is X.)

Therefore, the average oxygen content of the back reflection layer 130 of the first cells EC1 and EC2 may be 1 at% p to 25 at% p more than the average oxygen content of the back reflection layer 130 of the second cell CC. Where at% p is the numerical value of the atomic percentage (at%) relative to the oxygen content of the rear reflective layer 130 of the first cells EC1 and EC2 and the oxygen of the rear reflective layer 130 of the second cell CC. The numerical difference in atomic percent (at%) with respect to content.)

Here, the case where the average oxygen content of the rear reflective layer 130 included in the at least one second cell CC positioned in the central region of the substrate 100 is 30 at% is described as an example. The change is possible according to the optical and electrical characteristics of the photoelectric conversion unit PV included in the second cell CC. For example, the average oxygen content of the back reflection layer 130 included in the at least one second cell CC positioned in the central region of the substrate 100 may be determined within a range of 27at% to 47at%.

In addition, the oxygen content of the back reflection layer 130 included in the cells EC1 to CC to EC2 may be changed stepwise or gradually over the entire area of the substrate 100.

FIG. 7A illustrates a refractive index of the rear reflective layer 130 for each region of the substrate 100, and FIG. 7B illustrates an oxygen content of the rear reflective layer 130 for each region of the substrate 100. It is also.

For example, as shown in FIG. 7A, the present invention provides a structure in which the rear reflection layer 130 included in the plurality of cells EC1 to CC2 to EC2 progresses from the center region to the edge region of the substrate 100. In order to decrease the refractive index stepwise or gradually, as shown in FIG. 7B, as the process proceeds from the center area to the edge area of the substrate 100, the rear reflection layer included in the cells EC1 to CC2 to EC2 ( The oxygen content of 130 may increase step by step or gradually.

More specifically, as shown in FIG. 7, a plurality of cells EC1 to CC2 to the substrate 100 including the first cells EC1 and EC2 and the second cell CC are striped on the substrate 100 in a first direction y. In the case of being arranged in a long shape, the oxygen content of the back reflection layer 130 included in the plurality of cells EC1 to CC to EC2 increases stepwise as it proceeds from the center region to the edge region of the substrate 100 in the second direction x. Or gradually increase.

Here, the average oxygen content of the back reflection layer 130 included in the at least one first cell EC1 or EC2 may vary depending on the length direction y of the at least one first cell EC1 or EC2.

For example, the oxygen content of the rear reflective layer 130 at both ends of the at least one first cell EC1, EC2 is the oxygen content of the rear reflective layer 130 in the central region of the at least one first cell EC1, EC2. There may be more, and at least one first toward both ends in the central region of the at least one first cell (EC1, EC2) along the longitudinal direction (y) of the at least one first cell (EC1, EC2) The oxygen content contained in the back reflective layer 130 of the cells EC1 and EC2 may increase stepwise or gradually.

At this time, the oxygen content of the rear reflective layer 130 at both ends of the at least one first cell EC1, EC2 is the oxygen content of the rear reflective layer 130 in the central region of the at least one first cell EC1, EC2. It can be more than 1at% p to 25at% p.

In addition, the average oxygen content of the rear reflective layer 130 included in the at least one second cell CC may also vary depending on the length direction y of the at least one second cell CC.

For example, the oxygen content of the rear reflective layer 130 at both ends of the at least one second cell CC may be greater than the oxygen content of the rear reflective layer 130 in the central region of the at least one second cell CC. The rear reflective layer 130 of the at least one second cell CC toward both ends in the central region of the at least one second cell CC along the length direction y of the at least one second cell CC. The oxygen content contained in can be increased stepwise or gradually.

In addition, the oxygen content of the rear reflective layer 130 at both ends of the at least one second cell CC is 1at% p to the oxygen content of the rear reflective layer 130 in the central region of the at least one second cell CC. 25at% p can be a lot.

Accordingly, the light reflectance of the back reflecting layer 130 in the edge region of the substrate 100 may be increased than the light reflectance of the back reflecting layer 130 in the central region of the substrate 100, and thus, relatively optical and electrical By further increasing the light absorption of the photoelectric conversion part PV in the edge region of the substrate 100 having poor characteristics, the photoelectric conversion portion PV located in the edge region of the substrate 100 is produced as described in FIG. 4. The current can be made uniform with the current produced by the photoelectric conversion unit PV located in the central region of the substrate 100.

Thereby, the efficiency of a thin film solar cell module can be improved more.

6 to 7 illustrate an example in which the rear reflective layer 130 included in the cells EC1 to CC to EC2 includes a microcrystalline silicon oxide (n-mc-SiOx) doped with n-type impurities. Although described as above, the same may be applied to the case in which the rear reflective layer 130 includes zinc oxide (ZnO: Al).

Up to now, the photoelectric conversion part PV included in the cells EC1 to CC to EC2 has been described as an example in which one photoelectric conversion layer including a pin semiconductor layer is used. However, the back reflection layer 130 according to the present invention is used. The present invention can be applied even when there are a plurality of photoelectric conversion layers having a silver pin semiconductor layer.

8 to 9 are diagrams for explaining an example in which the oxygen content of the intermediate reflective layer along the region of the substrate is adjusted when the photoelectric conversion layer has two double junction structures.

8 to 9, the basic structure of the thin film solar cell module excluding the photoelectric conversion unit PV is the same as described with reference to FIGS. 1 to 3, and thus a detailed description thereof will be omitted.

8 to 9, the rear reflective layer 130 may be omitted, but when the rear reflective layer 130 is provided, the efficiency of the thin film solar cell module is further improved. The case where 130 is provided is demonstrated as an example. In this case, the rear reflective layer 130 may be applied in the same manner as described with reference to FIGS. 1 to 7.

8 to 9, the photoelectric conversion unit PV may be formed of two photoelectric conversion layers PV1 and PV2 including two pin semiconductor layers. Thus, the photoelectric conversion layers PV1 and PV2 may be formed as two. In individual cases, the intermediate reflective layer 120 may be further formed between the photoelectric conversion layers PV1 and PV2.

Here, the intermediate reflective layer 120 may be formed of zinc oxide (ZnO: Al) containing aluminum or fine crystalline silicon oxide doped with impurities of a first conductivity type or a second conductivity type, that is, p-type impurities or n-type impurities ( mc-SiOx).

In the present invention, when the intermediate reflective layer 120 includes fine crystalline silicon oxide (mc-SiOx), for example, the intermediate reflective layer 120 may include fine crystalline silicon oxide (n-mc-SiOx) doped with n-type impurities. The case of inclusion is demonstrated as an example.

As shown in (a) and (b) of FIG. 8, the photoelectric conversion unit included in the plurality of cells EC1 to CC2 including the first cells EC1 and EC2 and the second cell CC. Each of the PVs may include a first photoelectric conversion layer PV1 positioned on the first electrode 110 and a second photoelectric conversion layer PV2 positioned on the first photoelectric conversion layer PV1.

In this case, the intermediate reflective layer 120 included in each of the at least one first cell EC1 and EC2 and the second cell CC is positioned between the first photoelectric conversion layer PV1 and the second photoelectric conversion layer PV2. can do.

Here, each of the first photoelectric conversion layer PV1 and the second photoelectric conversion layer PV2 may include a first semiconductor layer including an impurity of a first conductivity type, for example, a p-type semiconductor layer and an impurity of a first conductivity type. A second semiconductor layer including an opposite impurity of a second conductivity type, for example, an n-type semiconductor layer, and an intrinsic semiconductor layer PV-i positioned between the first semiconductor layer and the second semiconductor layer. have.

Accordingly, as shown in FIGS. 8A and 8B, the first photoelectric conversion layer PV1 may be formed of the first p-type semiconductor layer PV1-p and the first p-type on the first electrode 110. The first intrinsic semiconductor layer PV1-i and the first n-type semiconductor layer PV1-n may be sequentially disposed on the semiconductor layers PV1-p. The second photoelectric conversion layer PV2 includes the second p-type semiconductor layer PV2-p on the intermediate reflective layer 120, the second intrinsic semiconductor layer PV2-i on the second p-type semiconductor layer PV2-p, and The second n-type semiconductor layer PV2-n may be sequentially disposed on the binary semiconductor layer PV2-i.

Therefore, the intermediate reflective layer 120 may be located between the first n-type semiconductor layer PV1-n and the second p-type semiconductor layer PV2-p.

As described above, when there are a plurality of photoelectric conversion layers PV1 and PV2 of the photoelectric conversion part PV, as described above with reference to FIG. 4, the thickness of the stacked photoelectric conversion part PV becomes relatively thick, and thus the photoelectric conversion part It is more difficult to uniformly form the thickness and electrical and optical characteristics of the PV in the entire region of the substrate 100, and also the photoelectricity of the first cells EC1 and EC2 located in the edge region of the substrate 100. The electrical and optical characteristics of the second photoelectric conversion layer PV2 that is stacked last among the conversion units PV may be significantly lowered.

Therefore, in consideration of the above, the present invention forms the oxygen content contained in at least one of the rear reflective layer 130 and the intermediate reflective layer 120 differently according to the position of the substrate 100, thereby forming the first cell EC1, Compensation for the photoelectric conversion capability of the second photoelectric conversion layer PV2 that is stacked last among the photoelectric conversion units PV of the EC2, so that the current output from the first cells EC1 and EC2 and the second cell CC The size can be made uniform.

Specifically, as shown in FIGS. 8A and 8B, the average of the intermediate reflective layer 120 included in the first cells EC1 and EC2 located in the edge region of the substrate 100 is illustrated. The oxygen content may be smaller than the average oxygen content of the intermediate reflective layer 120 included in the second cell CC positioned in the center region of the substrate 100.

At this time, as described above, the average oxygen content of the back reflection layer 130 included in the first cells EC1 and EC2 is greater than the average oxygen content of the back reflection layer 130 included in the second cell CC. Is more effective.

As such, when the oxygen content of the intermediate reflective layer 120 and the rear reflective layer 130 is changed according to the region of the substrate 100, the intermediate reflective layer 120 included in the first cells EC1 and EC2 is the second cell. It has a refractive index larger than that of the intermediate reflective layer 120 included in (CC), and accordingly, as shown in FIGS. 8A and 8B, the intermediate reflective layer included in the first cells EC1 and EC2. The reference numeral 120 may have a smaller light reflection amount and a larger light transmission amount than the intermediate reflective layer 120 included in the second cell CC.

In addition, as shown in (b) of FIG. 8, the back reflection layer 130 included in the first cells EC1 and EC2 is greater than that of the back reflection layer 130 included in the second cell CC as shown in FIG. 8 (a). It will reflect more light.

Accordingly, as shown in FIGS. 8A and 8B, the second photoelectric conversion layer PV2 included in the first cells EC1 and EC2 positioned in the edge region is the second region positioned in the central region. More light is incident than the second photoelectric layer included in the cell CC.

Therefore, the second intrinsic semiconductor layer PV2-i of FIG. 8B having a relatively low photoelectric conversion capability has the second intrinsic semiconductor layer PV2-i of FIG. 8A having a relatively high photoelectric conversion capability. Can produce a current equal to).

Thereby, the efficiency of a thin film solar cell module can be improved more.

In this case, the average oxygen content of the intermediate reflective layer 120 included in at least one of the first cells EC1 and EC2 positioned in the edge region of the substrate 100 may include at least one agent formed in the central region of the substrate 100. It may be 1at% p ~ 25at% p smaller than the average oxygen content of the intermediate reflective layer 120 included in the two cells (CC).

In addition, the oxygen content of the intermediate reflective layer 120 included in the cells EC1 to CC to EC2 may be changed stepwise or gradually over the entire area of the substrate 100.

FIG. 9A illustrates a refractive index of the intermediate reflective layer 120 for each region of the substrate 100, and FIG. 9B illustrates an oxygen content of the intermediate reflective layer 120 for each region of the substrate 100. It is also.

Specifically, as shown in (a) of FIG. 9, the present invention provides an intermediate reflective layer 120 included in a plurality of cells EC1 to CC2 to EC2 as it progresses from the center region to the edge region of the substrate 100. In order to increase the refractive index stepwise or gradually, as shown in FIG. 9B, an intermediate reflective layer included in the plurality of cells EC1 to CC to EC2 as it proceeds from the center region to the edge region of the substrate 100. The oxygen content of 120 can be reduced step by step or gradually.

That is, as shown in FIG. 9B, the rear reflection layer included in the plurality of cells EC1 to CC to EC2 as the process proceeds from the center region to the edge region of the substrate 100 in the second direction x. The oxygen content of 130 may decrease step by step or gradually.

Here, the average oxygen content of the intermediate reflective layer 120 included in the at least one first cell EC1 or EC2 may vary depending on the length direction y of the at least one first cell EC1 or EC2.

For example, as illustrated in FIG. 9A, the oxygen content at both ends of the intermediate reflective layer 120 included in the at least one first cell EC1 or EC2 is at least one first cell EC1. , May be smaller than the oxygen content in the central region of the intermediate reflective layer 120 included in EC2, and at this time, at least one first along the longitudinal direction y of the at least one first cell EC1, EC2. The average oxygen content of the intermediate reflective layer 120 included in at least one of the first cells EC1 and EC2 may be gradually or gradually increased toward both ends from the central region of the intermediate reflective layer 120 included in the cells EC1 and EC2. May decrease.

In this case, the oxygen content at both ends of the intermediate reflective layer 120 included in the at least one first cell EC1 or EC2 is equal to that of the intermediate reflective layer 120 included in the at least one first cell EC1 or EC2. It may be 1at% p to 25at% p smaller than the oxygen content in the central region.

In addition, the average oxygen content of the intermediate reflective layer 120 included in the at least one second cell CC may also vary along the length direction y of the at least one second cell CC.

For example, as illustrated in FIG. 9A, the oxygen content at both ends of the intermediate reflective layer 120 included in the at least one second cell CC is stored in the at least one second cell CC. The intermediate reflective layer may be smaller than the oxygen content in the central region of the intermediate reflective layer 120, and included in the at least one second cell CC along the length direction y of the at least one second cell CC. The average oxygen content of the intermediate reflective layer 120 included in the at least one second cell CC may decrease gradually or gradually toward both ends in the central region of the 120.

At this time, the oxygen content at both ends of the intermediate reflective layer 120 included in the at least one second cell CC is also increased in the central region of the intermediate reflective layer 120 included in the at least one second cell CC. It may be 1at% p to 25at% p smaller than the oxygen content.

Accordingly, the light transmittance of the intermediate reflective layer 120 in the edge region of the substrate 100 may be increased than the light transmittance of the intermediate reflective layer 120 in the central region of the substrate 100, and thus, relatively optical and electrical The second photoelectric conversion layer PV2 positioned in the edge region of the substrate 100 is further increased by increasing the light absorption rate of the photoelectric conversion portion PV in the edge region of the substrate 100 having poor characteristics. The current to be produced can be made uniform with the current generated by the second photoelectric conversion layer PV2 located in the center region of the substrate 100.

In addition, in the present invention, the oxygen content at the upper and lower boundary surfaces of the intermediate reflective layer 120 in contact with the photoelectric conversion layers PV1 and PV2 is intermediate in the intermediate reflective layer 120 included in the cells EC1 to CC to EC2. It may be smaller than the oxygen content in the middle portion of the reflective layer 120.

For example, as shown in FIG. 10, the intermediate reflective layer 120 according to the present invention may be formed of a plurality of layers having different oxygen contents.

FIG. 10 is a view for explaining in detail the vertical oxygen content of the intermediate reflective layer included in the first cell and the second cell in FIG. 8.

As illustrated in FIG. 10, the intermediate reflective layer 120 included in the first cells EC1 and EC2 and the second cell CC includes the first n-type semiconductor layer PV− of the first photoelectric conversion layer PV1. n) a first layer 120a in contact with the second layer, a second layer 120b formed on the first layer 120a of the intermediate reflective layer 120, and a second photoelectric conversion layer PV2 formed on the second layer 120b. The third layer 120c may be in contact with the second p-type semiconductor layer PV-p.

At this time, the first layer 120a and the second p-type semiconductor layer PV- of the second photoelectric conversion layer PV2 are in contact with the first n-type semiconductor layer PV-n of the first photoelectric conversion layer PV1. The oxygen content of the third layer 120c in contact with p) may be smaller than the oxygen content of the second layer 120b.

This is because the electrical conductivity of the intermediate reflective layer 120 may decrease when the oxygen content at the upper and lower boundary surfaces of the intermediate reflective layer 120 contacting the photoelectric conversion layer is excessively large.

That is, when the oxygen content at the upper and lower boundary surfaces of the intermediate reflective layer 120 contacting the first photoelectric conversion layer PV1 and the second photoelectric conversion layer PV2 is excessively large, the first photoelectric conversion layer PV1 and Carriers caught in the second photoelectric conversion layer PV2 may be recombined with oxygen at upper and lower interfaces of the intermediate reflective layer 120 to be extinguished. In the intermediate reflective layer 120, the first photoelectric conversion layer PV1 and the second may be destroyed. When the oxygen content at the upper and lower boundary surfaces in contact with the photoelectric conversion layer PV2 is relatively small, the amount of carrier recombination with oxygen can be prevented to a minimum.

11 is a view for explaining an example in which the oxygen content of the intermediate reflective layer along the region of the substrate is adjusted when the photoelectric conversion layer has three triple junction structures.

In FIG. 11, since the basic structure of the thin film solar cell module except for the photoelectric conversion unit PV is the same as described with reference to FIGS. 1 to 3, a detailed description thereof will be omitted.

However, unlike FIG. 1 to FIG. 3, the rear reflective layer 130 may be omitted. However, when the rear reflective layer 130 is provided, the efficiency of the thin film solar cell module is further improved. The case provided with is demonstrated as an example. In this case, the rear reflective layer 130 may be applied in the same manner as described with reference to FIGS. 1 to 7.

In FIG. 11, the photoelectric conversion unit PV may be formed of three photoelectric conversion layers PV1, PV2, and PV3 including three pin semiconductor layers. Thus, the photoelectric conversion layers PV1, PV2, and PV3 may be formed. In the case of three, the first intermediate reflective layer 120A is between the first photoelectric conversion layer PV1 and the second photoelectric conversion layer PV2, and between the second photoelectric conversion layer PV2 and the third photoelectric conversion layer PV3. The second intermediate reflective layer 120B may be formed thereon.

Here, the materials and structures of the first intermediate reflective layer 120A and the second intermediate reflective layer 120B may be the same as described above with reference to FIGS. 8 to 10.

As shown in FIGS. 11A and 11B, the photoelectric conversion unit included in the plurality of cells EC1 to CC2 including the first cells EC1 and EC2 and the second cell CC. Each of the PVs may include a first photoelectric conversion layer PV1 positioned on the first electrode 110 and a second photoelectric conversion layer PV2 and a second photoelectric conversion layer PV2 positioned on the first photoelectric conversion layer PV1. ) May include a third photoelectric conversion layer PV3.

In this case, the first intermediate reflective layer 120A is disposed between the first photoelectric conversion layer PV1 and the second photoelectric conversion layer PV2, and the first intermediate reflective layer 120A is disposed between the second photoelectric conversion layer PV2 and the third photoelectric conversion layer PV3. 2 intermediate reflective layer 120B may be located.

Here, each of the first photoelectric conversion layer PV1, the second photoelectric conversion layer PV2, and the third photoelectric conversion layer PV3 may have a first conductivity type as illustrated in FIGS. 11A and 11B. A first semiconductor layer containing an impurity of, for example, a p type semiconductor layer, a second semiconductor layer containing an impurity of a second conductivity type opposite to an impurity of the first conductivity type, for example an n type semiconductor layer, and The intrinsic semiconductor layer PV-i may be disposed between the first semiconductor layer and the second semiconductor layer.

That is, as shown in FIG. 11, the first photoelectric conversion layer PV1 is disposed on the first p-type semiconductor layer PV1-p and the first p-type semiconductor layer PV1-p on the first electrode 110. The first n-type semiconductor layer PV1-n may be sequentially disposed on the first intrinsic semiconductor layer PV1-i and the first intrinsic semiconductor layer PV1-i, and the second photoelectric conversion layer PV2 may be The second intrinsic semiconductor layer PV2-i and the second intrinsic semiconductor layer PV2-p on the first intermediate reflective layer 120A and the second p-type semiconductor layer PV2-p on the second p-type semiconductor layer PV2-p. -i) The second n-type semiconductor layer PV2-n may be sequentially disposed, and the third photoelectric conversion layer PV3 may be disposed on the second intermediate reflective layer 120B. ), The third intrinsic semiconductor layer PV3-i on the third p-type semiconductor layer PV3-p, and the third n-type semiconductor layer PV3-n on the third intrinsic semiconductor layer PV3-i. Can be located.

Accordingly, the first intermediate reflective layer 120A may be located between the first n-type semiconductor layer PV1-n and the second p-type semiconductor layer PV2-p, and the second intermediate reflective layer 120B may be disposed in the second region. The semiconductor device may be positioned between the n-type semiconductor layer PV2-n and the third p-type semiconductor layer PV3-p.

As described above, when there are three photoelectric conversion layers PV1, PV2, and PV3 of the photoelectric conversion part PV, the thickness of the stacked photoelectric conversion part PV becomes thicker, so that the thickness of the photoelectric conversion part PV and the electrical And it is more difficult to uniformly form the optical characteristics in the entire region of the substrate 100, and the most of the photoelectric conversion units PV of the first cells EC1 and EC2 located in the edge region of the substrate 100. The electrical and optical properties of the third photoelectric conversion layer PV3 that are later stacked may be significantly lowered.

Therefore, in view of the above, the present invention forms the oxygen content contained in the second intermediate reflective layer 120B differently according to the position of the substrate 100, thereby forming a photoelectric conversion unit (for the first cells EC1 and EC2). Compensation for the photoelectric conversion capability of the third photoelectric conversion layer PV3, which is later stacked among PV, may make the magnitude of the current output from the first cells EC1 and EC2 and the second cell CC uniform. .

Specifically, as shown in FIGS. 11A and 11B, the second intermediate reflective layer 120B included in the first cells EC1 and EC2 positioned in the edge region of the substrate 100 may be used. The average oxygen content of can be made smaller than the average oxygen content of the second intermediate reflective layer 120B included in the second cell CC located in the center region of the substrate 100.

At this time, as described above, the average oxygen content of the back reflection layer 130 included in the first cells EC1 and EC2 is greater than the average oxygen content of the back reflection layer 130 included in the second cell CC. Is more effective.

As such, when the oxygen content of the intermediate reflective layer 120 and the rear reflective layer 130 is changed according to the region of the substrate 100, the second intermediate reflective layer 120B included in the first cells EC1 and EC2 may be formed. It has a refractive index larger than that of the second intermediate reflective layer 120B included in the two cells CC. Accordingly, as shown in FIGS. 11A and 11B, the first cells EC1 and EC2 are disposed in the first cells EC1 and EC2. The second intermediate reflective layer 120B included may have a smaller light reflection amount and a larger light transmittance than the second intermediate reflective layer 120B included in the second cell CC.

In addition, as shown in (b) of FIG. 11, the back reflection layer 130 included in the first cells EC1 and EC2 may be smaller than the back reflection layer 130 included in the second cell CC as shown in FIG. 8 (a). It will reflect more light.

Accordingly, as illustrated in FIGS. 11A and 11B, the third photoelectric conversion layer PV3 included in the first cells EC1 and EC2 positioned in the edge region is the second region positioned in the central region. More light is received than the third photoelectric layer included in the cell CC.

Therefore, the third intrinsic semiconductor layer PV3-i of FIG. 11B having a relatively low photoelectric conversion capability has the third intrinsic semiconductor layer PV3-i of FIG. 11A having a high photoelectric conversion capability. Can produce a current equal to).

Thereby, the efficiency of a thin film solar cell module can be improved more.

In this case, the average oxygen content of the second intermediate reflective layer 120B included in the at least one first cell EC1, EC2 located in the edge region of the substrate 100 is at least one located in the central region of the substrate 100. It may be 1at% p to 25at% p smaller than the oxygen content of the second intermediate reflective layer 120B included in the second cell CC.

In addition, the oxygen content of the intermediate reflective layer 120 included in the cells EC1 to CC to EC2 may be changed stepwise or gradually over the entire area of the substrate 100.

In addition, in FIG. 11, the oxygen content contained in the second intermediate reflective layer 120B is described as an example only when the oxygen content contained in the second intermediate reflective layer 120B is formed differently according to the position of the substrate 100. It may be formed differently depending on the position of the (100).

12 to 14 below show an example of application in which the oxygen content of the second intermediate reflective layer and the rear reflective layer is actually applied in accordance with the area of the substrate when the photoelectric conversion unit of the thin film solar cell module of FIG. 11 has a triple junction structure. It is a figure for demonstrating.

In detail, (a) of FIG. 12 illustrates the refractive index of the second intermediate reflective layer 120B along the region of the substrate 100, and (b) illustrates the second intermediate reflective layer 120B along the region of the substrate 100. The oxygen content of is shown.

In addition, (a) of FIG. 13 illustrates the refractive index of the rear reflective layer 130 along the region of the substrate 100, and (b) illustrates the oxygen content of the rear reflective layer 130 along the region of the substrate 100. It was.

In addition, in FIG. 14A, the comparative example is an example in which the refractive indices of the second intermediate reflective layer 120B and the rear reflective layer 130 are substantially the same within an error range regardless of the region of the substrate 100. 12 and 13 illustrate an example in which the refractive index and the oxygen content are actually applied to the second intermediate reflective layer 120B and the rear reflective layer 130.

14A is a table for comparing the effect of this invention with the comparative example of FIG. 14A, and the numerical value described in this invention column is a numerical value based on a comparative example.

12A and 12B show the refractive index and the oxygen content of the second intermediate reflective layer 120B along the region of the substrate 100, and FIGS. 13A and 13B illustrate the substrate 100, respectively. Refractive index and oxygen content of the back reflection layer 130 according to the region are shown, and FIGS. 14A and 14B show the second intermediate reflective layer 120B according to the region of the substrate 100 as shown in FIGS. 12 and 13. And a table for explaining the effect when the oxygen content of the rear reflective layer 130 is controlled.

In the thin film solar cell module having the triple junction structure applied to FIGS. 12 to 14, the first intrinsic semiconductor layer PV1-i of the first photoelectric conversion layer PV1 may be amorphous silicon (a-Si) or a second photoelectric conversion. The second intrinsic semiconductor layer PV2-i of the layer PV2 is amorphous silicon (a-SiGe) containing germanium, and the third intrinsic semiconductor layer PV3-i of the third photoelectric conversion layer PV3 is fine crystalline. Silicon (mc-Si) was included, and the positions of the pin semiconductor layers of the first to third photoelectric conversion layers PV1, PV2, and PV3 were the same as illustrated in FIG. 11.

Here, the second intermediate reflective layer 120B and the rear reflective layer 130 are formed of fine crystalline silicon oxide (n-mc-SiOx) doped with n-type impurities.

Here, the oxygen content of the first intermediate reflective layer 120A is formed to be uniform according to the region of the substrate 100, and the second intermediate reflective layer 120B is shown in FIGS. 12A and 14A. As shown in FIG. 12B, in order to gradually increase or decrease the refractive index from 1.92 to 2.04 as it proceeds from the center region to the edge region of the substrate 100, the center region of the substrate 100. As it progressed to the edge region at, the oxygen content was controlled to gradually or gradually decrease from 43 at% to 37 at%.

Accordingly, the oxygen content of the second intermediate reflective layer 120B in the central region of the substrate 100 is 43at%, which is approximately 6at% than the 37at% of the oxygen content of the second intermediate reflective layer 120B in the edge region of the substrate 100. p was contained higher.

In addition, as shown in FIGS. 13A and 14A, the rear reflective layer 130 gradually or gradually decreases the refractive index from 1.99 to 1.88 as it proceeds from the center region to the edge region of the substrate 100. In order to make it possible, as shown in FIG. 13B, the oxygen content was gradually or stepwise increased from 41at% to 47at% as it progressed from the center region to the edge region of the substrate 100.

Accordingly, the oxygen content of the rear reflective layer 130 in the central region of the substrate 100 is 41 at%, which is approximately 6 at% p lower than the 47 at% of the oxygen content of the rear reflective layer 130 in the edge region of the substrate 100. It was.

As such, when the second intermediate reflective layer 120B and the rear reflective layer 130 of the thin film solar cell module are formed, as shown in FIG. 14B, the efficiency of the thin film solar cell module increases. have.

More specifically, in FIG. 14B, when the open-circuit voltage Voc is based on a comparative example, the present invention has a difference of 0.998, which is 0.002, and when converted into a percentage, 0.2% within an error range. Almost the same.

However, when the short-circuit current Isc is based on the comparative example, the present invention shows that the difference is 1.019, which is approximately 0.02, and is improved by 2% when converted into a percentage.

In addition, when the fill factor (FF) is based on the comparative example, the present invention is almost the same within the error range of 0.999, the photoelectric conversion efficiency (Eff) and the maximum output voltage (Pmax) is based on the comparative example , The present invention is 1.016, it can be seen that 1.6% improved when converted to a percentage.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims (22)

Board; And
And a plurality of cells including a first electrode positioned on the substrate, a photoelectric converter positioned on the first electrode, a rear reflective layer positioned on the photoelectric converter, and a second electrode positioned on the rear reflective layer. ,
The plurality of cells includes at least one first cell positioned in an edge region of the substrate and at least one second cell positioned in a central region of the substrate,
The average oxygen content of the back reflection layer included in the at least one first cell located in the edge region of the substrate is higher than the average oxygen content of the back reflection layer included in the at least one second cell located in the central region of the substrate, ,
The at least one first cell is elongated in a stripe shape on the substrate,
The thin film solar cell module of claim 1, wherein the average oxygen content of the back reflecting layer included in the at least one first cell is changed in the longitudinal direction of the at least one first cell. According to claim 1,
The thin film solar cell module of which the oxygen content of the rear reflective layer increases stepwise or gradually as it proceeds from the center region to the edge region of the substrate. According to claim 1,
The average oxygen content of the back reflection layer included in the at least one first cell positioned in the edge region of the substrate is higher than the average oxygen content of the back reflection layer included in the at least one second cell located in the central region of the substrate. 1at% p (atomic percent) to 25at% p Many thin film solar cell modules. According to claim 1,
The at least one first cell is disposed long in the form of a stripe on the substrate,
The thin film solar cell module of claim 1, wherein the average oxygen content of the back reflecting layer included in the at least one first cell is changed in the longitudinal direction of the at least one first cell. According to claim 1,
The oxygen content of the rear reflective layer at both ends of the at least one first cell is more than the oxygen content of the rear reflective layer in the central region of the at least one first cell. The method of claim 5,
A thin film in which the oxygen content contained in the rear reflective layer of the at least one first cell increases gradually or gradually from the central region of the at least one first cell along the longitudinal direction of the at least one first cell. Solar module. According to claim 1,
The at least one second cell is disposed long in the form of a stripe on the substrate,
The thin film solar cell module of claim 1, wherein the average oxygen content of the back reflecting layer included in the at least one second cell is changed in the longitudinal direction of the at least one second cell. The method of claim 7, wherein
And the oxygen content of the rear reflective layer at both ends of the at least one second cell is greater than the oxygen content of the rear reflective layer in the central region of the at least one second cell. The method of claim 8,
A thin film in which the oxygen content contained in the rear reflective layer of the at least one second cell increases stepwise or gradually toward both ends in the central region of the at least one second cell along the longitudinal direction of the at least one second cell. Solar module. According to claim 1,
Each rear reflective layer included in the plurality of cells includes a thin crystalline silicon oxide (mc-SiOx) or zinc oxide (ZnO: Al) containing aluminum. Board; And
And a plurality of cells formed on the substrate and having a first electrode positioned on the substrate, a photoelectric conversion portion positioned on the first electrode, and a second electrode positioned on the photoelectric conversion portion.
The plurality of cells includes at least one first cell positioned in an edge region of the substrate and at least one second cell positioned in a central region of the substrate;
Each of the photoelectric conversion units included in the at least one first cell and the second cell includes a plurality of photoelectric conversion layers, and each of the at least one first cell and the second cell each between the plurality of photoelectric conversion layers. Further comprising an intermediate reflective layer,
The average oxygen content of the intermediate reflective layer included in the first cell located at the edge region of the substrate is less than the average oxygen content of the intermediate reflective layer included in the second cell located at the central region of the substrate,
The at least one first cell is disposed long in the form of a stripe on the substrate,
The thin film solar cell module of which the oxygen content of the intermediate reflective layer included in the at least one first cell is changed along a length direction of the at least one first cell. The method of claim 11, wherein
The thin film solar cell module of which the oxygen content of the intermediate reflective layer decreases stepwise or gradually as it proceeds from the center region to the edge region of the substrate. The method of claim 11, wherein
Oxygen content of the intermediate reflective layer included in the at least one first cell positioned in the edge region of the substrate is 1at than average oxygen content of the intermediate reflective layer included in the at least one second cell positioned in the central region of the substrate. % p ~ 25at% p Small thin film solar cell module. delete The method of claim 11, wherein
The thin film solar cell module of which the oxygen content at both ends of the intermediate reflective layer included in the at least one first cell is smaller than the oxygen content in the central region of the intermediate reflective layer included in the at least one first cell. The method of claim 15,
The oxygen content of the intermediate reflective layer included in the at least one first cell is gradually increased from the central region of the intermediate reflective layer included in the at least one first cell along the longitudinal direction of the at least one first cell to both ends. Gradually decreasing thin film solar cell module. The method of claim 11, wherein
The at least one second cell is disposed long in the form of a stripe on the substrate,
The thin film solar cell module, wherein the average oxygen content of the intermediate reflective layer included in the at least one second cell is changed along a length direction of the at least one second cell. The method of claim 17,
The thin film solar cell module of which the oxygen content at both ends of the intermediate reflective layer included in the at least one second cell is smaller than the oxygen content in the central region of the intermediate reflective layer included in the at least one second cell. The method of claim 18,
The average oxygen content of the intermediate reflective layer included in the at least one second cell gradually increases from the central region of the intermediate reflective layer included in the at least one second cell along the longitudinal direction of the at least one second cell. Or a thin film solar cell module that gradually decreases. The method of claim 11, wherein
Each of the photoelectric conversion parts included in the plurality of cells includes a first photoelectric conversion layer positioned on the first electrode and a second photoelectric conversion layer positioned on the first photoelectric conversion layer,
The intermediate reflective layer included in the plurality of cells is a thin film solar cell module positioned between the first photoelectric conversion layer and the second photoelectric conversion layer. The method of claim 11, wherein
Each of the photoelectric conversion units included in the plurality of cells may include a first photoelectric conversion layer positioned on the first electrode, a second photoelectric conversion layer positioned on the first photoelectric conversion layer, and a second photoelectric conversion layer. A third photoelectric conversion layer,
The intermediate reflective layer included in the plurality of cells is a thin film solar cell module positioned between the second photoelectric conversion layer and the third photoelectric conversion layer. The method of claim 11, wherein
Each intermediate reflective layer included in the plurality of cells includes a thin crystalline silicon oxide (mc-SiOx) or zinc oxide containing aluminum (ZnO: Al).

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