JP2003046103A - Thin film solar battery and method for installing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin film solar battery and a method for installing the same capable of improving power generation efficiency by avoiding the reduction of a light quantity to be incident on a thin film photoelectric conversion layer in spite of the presence of surface reflected light, for improving light usability. SOLUTION: Light incident from the pin hole 7 of a second reflection layer 6 through a group of condenser lenses 9 is subjected to multireflection between a first reflection layer 5 and a second reflection layer 7. Thus, the light quantity with which the thin film photoelectric conversion layer 3 is irradiated is increased to improve the power generation efficiency.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a thin film solar cell and a method for installing the same.

[0002]

Thin-film solar cell of the Related Art Generally, as shown in FIG. 13, on a transparent insulating substrate 101 such as glass, SnO _2,
A transparent conductive film 102 such as ITO or ZnO is formed, and a-Si: H, a-SiGe: H, or a- is formed thereon.
A p-type impurity-doped semiconductor layer p-layer 103, an intrinsic semiconductor layer i-layer 104, and an n-type impurity-doped layer n-layer 105 made of an amorphous semiconductor such as SiC: H are laminated in this order to form a thin film. The photoelectric conversion layer 106 is formed, and a transparent conductive film 107 for effectively utilizing reflected light from the back surface and a back surface electrode 108 made of Al or Ag having a relatively high reflectance are stacked on the photoelectric conversion layer 106.

In order to improve power generation efficiency, a tandem structure thin film solar cell has been proposed as shown in FIG. This tandem structure thin-film solar cell has a structure in which a plurality of thin-film photoelectric conversion layers 106 each including a p-layer 103, an i-layer 104, and an n-layer 105 having different band gaps are stacked.
By photoelectrically converting light of different wavelengths in each thin-film photoelectric conversion layer 106, the total open circuit voltage is increased,
Achieves an increase in power generation efficiency.

[0004]

In the thin film solar cell and the tandem structure thin film solar cell, the transparent insulating substrate 1 is used.
By optimizing the film thickness of the transparent conductive films 102 and 107 on 01, light having a wavelength required for photoelectric conversion in the thin film photoelectric conversion layer 106 is efficiently absorbed in the thin film photoelectric conversion layer 106. Is designed to. However, these optimized designs are based on the transparent conductive films 102 and 10.
The optical interference effect in 7 is used, and 10% to 20% is applied to the light of the central wavelength realized by the optimized design.
% Of surface reflected light exists, and the surface reflected light further increases as the wavelength of light deviates from the central wavelength realized by the optimized design. Such an increase in the surface-reflected light contributes to a decrease in light utilization efficiency. In particular, in a tandem structure solar cell that uses light in a wide wavelength band for photoelectric conversion, light loss due to this surface reflection becomes significant.

Therefore, an object of the present invention is to prevent the amount of light incident on the thin-film photoelectric conversion layer from decreasing even if there is surface-reflected light, thereby improving light utilization efficiency and power generation efficiency. It is to provide a thin film solar cell and a method for installing the same.

[0006]

In order to solve the above-mentioned problems, a thin film solar cell of the present invention comprises a transparent substrate, a first reflective layer located on one surface side of the transparent substrate, and the transparent substrate. A thin film photoelectric conversion layer located between the one surface of the transparent substrate and the first reflective layer, a second reflective layer having a pinhole group and provided on the other surface of the transparent substrate, and the pinhole. The group is provided with a condenser lens group for condensing incident light.

With the above arrangement, the incident light is condensed by the condenser lens group on each pinhole of the pinhole group of the second reflection film. And the light incident from each pinhole is
Multiple reflection occurs between the first reflective layer and the second reflective layer.
Therefore, the amount of light with which the thin film photoelectric conversion layer is irradiated is increased, and the power generation efficiency is increased.

In one embodiment, the thin-film photoelectric conversion layer has a p-type impurity-doped amorphous semiconductor layer and an n-type impurity-doped amorphous semiconductor layer sandwiching an i-layer which is an intrinsic amorphous semiconductor layer. It is composed of a pin structure.

In the above embodiment, since the thin film photoelectric conversion layer is made of an amorphous semiconductor and has a pin structure, it has a high absorption coefficient, is thin and can be manufactured at low cost, and
It has an advantage that the photoelectric conversion efficiency is relatively high.

Further, one embodiment has a tandem structure in which a plurality of thin film photoelectric conversion layers are laminated.

In the above embodiment, since the thin film photoelectric conversion layer has a tandem structure in which a plurality of layers are laminated, the open circuit voltage of the solar cell can be increased. Further, by making the band gaps of the plurality of thin film photoelectric conversion layers different, it is possible to efficiently photoelectrically convert light of each wavelength in each thin film photoelectric conversion layer. Therefore, the above embodiment can increase the power generation efficiency.

In one embodiment, the condensing lens is a hemispherical lens, and the center of the hemispherical lens substantially overlaps with the center of the pinhole provided in the second reflective layer. And the hemispherical lens group is mounted on the second reflective layer.

According to the above embodiment, the hemispherical lens group is mounted on the second reflective layer such that the center of the hemispherical lens substantially overlaps the center of the pinhole of the second reflective layer. Therefore, the hemispherical lens efficiently collects the incident light on the pinhole of the second reflective layer. Therefore, power generation efficiency can be increased.

Further, in one embodiment, the condenser lens is made of an ultraviolet curable resin.

In the above-described embodiment, since the condenser lens is made of the ultraviolet curable resin, the 2P method (photopolymerization method: Photo) is used.
It is possible to collectively form the condenser lens group by a simple method such as Polymerization), and it is possible to realize the cost reduction of the thin film solar cell.

Further, in one embodiment, the condenser lens group is in a close-packed state in which six hemispherical lenses are in contact with each one hemispherical lens.

In the above-mentioned embodiment, since each hemispherical lens is in a close-packed state in which six hemispherical lenses are in contact with each other, the total condensing area can be widened and the power generation can be increased. The efficiency can be increased.

Further, in the method for installing a thin-film solar cell of the present invention, the thin-film solar cell of the above-mentioned embodiment is adjacent to a specific hemispherical lens, and two hemispherical lenses adjacent to each other are in contact with each other. It is characterized in that it is installed so that a straight line connecting the point and the center point of the specific hemispherical lens faces approximately the east-west direction.

According to the present invention, each hemispherical lens is not in direct contact with the adjacent hemispherical lens in the east-west direction even in the morning and evening when light is incident from the east-west direction and from an oblique direction. Since there is a space between hemispherical lenses in the east-west direction, each hemispherical lens receives a large amount of light even in the morning and evening when light is incident from the east-west direction and obliquely. You can Therefore, high power generation efficiency can be maintained in the morning and evening.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The thin film solar cell of the present invention will be described in detail below with reference to the embodiments shown in the drawings.

(Embodiment 1) FIG. 1 shows a schematic sectional view of a thin film solar cell according to Embodiment 1 of the present invention.

In this thin film solar cell, a transparent conductive film 2, a thin film photoelectric conversion layer 3, a transparent conductive film 4 and a first reflective layer 5 are sequentially laminated on one surface of a transparent insulating substrate 1. Further, a second reflective layer 6 having a pinhole group 7 is formed on the other surface of the transparent insulating substrate 1, and the pinholes 7 of the pinhole group 7 are incident on the reflective layer 6. A collective lens group 9 arranged to collect the light 8 is formed.

Each condenser lens 9 of the condenser lens group 9 is
It is a hemispherical lens 9. The center of each hemispherical lens 9 is made to substantially overlap with the center of the pinhole 7 of the pinhole group 7 of the second reflection layer 9, and the hemispherical lens 9 makes the incident light into Pinhole 7 in reflective layer 6
It is designed to collect light efficiently.

In the above structure, when the thin film solar cell is irradiated with light such as sunlight, incident light 8 is condensed by the condenser lens group 9 to the pinhole group 7 formed on the second reflection layer 6. The light is collected, sequentially passes through the transparent substrate 1, the transparent conductive film 2, the thin film photoelectric conversion layer 3, and the transparent conductive film 4, and is reflected by the first reflective layer 5. The light (dotted line) reflected by the first reflective layer 5 passes through the transparent conductive film 4, enters the thin film photoelectric conversion layer 3 again, and is transmitted therethrough. This transmitted light passes through the transparent conductive film 2
After passing through, the light is reflected by the second reflective layer 6 and enters the thin film photoelectric conversion layer 3 again. In addition, the thin film photoelectric conversion layer 3
The light reflected in (1) is also reflected by the first reflective layer 5 and the second reflective layer 6 and again enters the thin film photoelectric conversion layer 3. In this way, the pinhole group 7 is formed between the first reflective layer 5, the second reflective layer 6 and the thin film photoelectric conversion layer 3.
The incident light 8 is efficiently reflected on the thin-film photoelectric conversion layer 3 due to the multiple reflection of the light incident on the thin-film photoelectric conversion layer 3, so that the power generation efficiency of the thin-film photoelectric conversion layer 3 can be increased.

(Second Embodiment) A thin film solar cell according to a second embodiment of the present invention shown in FIG.
The transparent conductive film 2, the first thin film photoelectric conversion layer 31, the second thin film photoelectric conversion layer 32, the third thin film photoelectric conversion layer 33, the transparent conductive film 4, and the first reflective layer 5 are sequentially laminated. Further, on the other surface of the transparent substrate 1, a second reflective layer 6 having a pinhole group 7 and a collection arranged to collect incident light 8 on each pinhole 7 of the pinhole group 7. The optical lens group 9 is formed.

The first, second and third thin film photoelectric conversion layers 3
1, 32, and 33 are three-layer tandem structures, which are connected in series. Further, the band gaps of the first, second and third thin film photoelectric conversion layers 31, 32 and 33 are different from each other.

According to the above configuration, the incident light 8 on the thin-film solar cell is condensed by the condenser lens group 9 and enters the transparent insulating substrate 1 through the pinhole 7 of the pinhole group 7. This incident light 8 is generated between the first reflective layer 5, the second reflective layer 6 and the first, second and third thin film photoelectric conversion layers 31, 32 and 33, as in the thin film solar cell of FIG. Then, the incident light 8 is multiply reflected and the incident light 8 is incident on the first, second and third thin film photoelectric conversion layers 3
1, 32, 33 are efficiently irradiated. Therefore, first,
The power generation efficiency of the second and third thin film photoelectric conversion layers 31, 32 and 33 can be increased.

Furthermore, since the first, second and third thin film photoelectric conversion layers 31, 32 and 33 have a three-layer tandem structure and are connected in series, the open circuit voltage between the terminals increases. Further, power generation efficiency can be increased.

Furthermore, since the band gaps of the first, second and third thin film photoelectric conversion layers 31, 32 and 33 are different from each other, the first, second and third thin film photoelectric conversion layers 31, The wavelengths of light absorbed for photoelectric conversion at 32 and 33 are different, and light over a wide wavelength range can be used for photoelectric conversion more efficiently, and therefore the power generation efficiency can be further increased.

3 and 4 show a planar arrangement structure of the condenser lenses 9 of the condenser lens group 9.

In the condensing lens group 9 shown in FIG. 3, a plurality of hemispherical lenses 9 are regularly arranged in the vertical and horizontal directions, and four hemispherical lenses 9 are arranged in one hemispherical lens 9 from above, below, left and right.
Are in contact.

In this planar arrangement structure, the condenser lens group 9
The light incident on the reflection area 10 other than the area to which the hemispherical lens 9 is attached is not focused on the pinhole group 7, and the second reflection layer 6 is formed on the transparent insulating substrate 1.
Since it is reflected by, the light loss becomes large.

On the other hand, in the condensing lens group 9 shown in FIG. 4, a row composed of a plurality of hemispherical lenses 9 arranged in the lateral direction is an adjacent upper and lower row, and the arrangement pitch of the hemispherical lenses 9 is half. 6 pitches around each hemispherical lens 9
It has a close-packed arrangement structure in which individual hemispherical lenses 9 are in contact with each other.

In the condensing lens group 9 shown in FIG. 4, the reflection area 10 is smaller than the reflection area 10 shown in FIG. 3, so that the light utilization efficiency is increased and the power generation efficiency can be increased.

In the first and second embodiments, the condenser lens group 9 shown in FIG. 4 is used. However, it is also possible to use the condenser lens group 9 shown in FIG.

(Embodiment 3) FIG. 5 is a diagram for explaining a method of installing the thin film solar cells of Embodiments 1 and 2 having the condenser lens group 9 shown in FIG.

The sunlight is not always radiated directly above the solar cell, and in the morning and the evening, the sunlight is incident on the thin film solar cell from an oblique direction.

FIG. 6 shows a state where the condenser lens group 9 in FIG. 5 is obliquely irradiated with light from the direction of the arrow 11 which is continuously continuous on a straight line, and FIG. 5
At a certain condensing lens 91, and
When the light is obliquely irradiated from the direction of the arrow 12 which is the direction of the straight line connecting the point where the two condensing lenses 92 and 93 adjacent to each other are in contact with the center point of the specific condensing lens 91. It shows the situation.

In the case of FIG. 6, since a plurality of hemispherical lenses 9 of the condenser lens group 9 are continuously formed in a straight line in the light incident direction, the light 8 incident obliquely is formed.
However, it becomes impossible to efficiently collect the light obliquely irradiated by the adjacent hemispherical lens 9 by the hemispherical lens 9. As shown in FIG. 6, from a direction inclined more than the inclination of a straight line passing through the pinhole 7 located in the center of a specific hemispherical lens 94 and circumscribing the condensing lens 95 adjacent to the hemispherical lens. When light is incident, the light shielding effect by the adjacent hemispherical lenses 95 becomes remarkable, leading to deterioration of the light utilization rate, that is, deterioration of power generation efficiency.

On the other hand, in the case of FIG. 7, since hemispherical lens groups 9 are discretely formed in the direction 12 in which light is incident in FIG. 5, light shielding by adjacent hemispherical lenses 9 is performed. Since the effect is remarkably reduced, as shown in FIG. 7, it is possible to efficiently guide the light 8 incident from a direction further inclined as compared with the case of FIG. 6 to the hemispherical lens 9.

Therefore, in the morning and in the evening, the directions in which light is obliquely incident, that is, the east-west direction, are adjacent to a specific condenser lens 91 in FIG. 5 and are adjacent to each other. The direction of a straight line connecting the point where 92 and 93 are in contact with the center point of the specific condenser lens 91 (arrow 1
2)), more efficient light collection can be realized, and a thin film solar cell with high power generation efficiency can be obtained.

Example 1 The thin film solar cell of the present invention shown in FIG. 1 was prepared according to the process shown in FIGS.

First, as shown in FIG. 8, after forming a comb-shaped current collecting electrode (not shown) on a glass substrate 1 as a transparent substrate, a SnO ₂ transparent conductive layer 2 having a film thickness of 30 nm is formed by reactive sputtering. did. Next, a photoelectric conversion layer 3 in which a p-layer that is a p-type impurity-doped semiconductor layer, an i-layer that is an intrinsic semiconductor layer, and an n-layer that is an n-type impurity-doped layer are stacked in this order is subjected to plasma CVD (chemical vapor deposition). ) It was formed by a vapor phase growth method using an apparatus. Each semiconductor layer is made of Si.
A-SiC having a film thickness of 15 nm that was vapor-phase grown using a mixed gas of H ₄ gas, H ₂ gas, CH ₄ gas, and B ₂ H ₆ gas:
H p layer, a-Si: H i layer having a film thickness of 200 nm vapor-phase grown using a mixed gas of SiH ₄ gas and H ₂ gas, S
An n-layer of a-Si: H having a film thickness of 15 nm was vapor-grown using a mixed gas of iH ₄ gas, H ₂ gas, and PH ₃ gas. After forming the photoelectric conversion layer 3, S having a thickness of 30 nm is formed.
The nO ₂ transparent conductive layer 4 was formed by reactive sputtering, and further, the first reflective layer 5 made of Al and having a film thickness of 100 nm was formed by sputtering. Here, the first reflective layer 5 also serves as a collector electrode.

Next, as shown in FIG. 9, the first reflective layer 5
A Ta protective film 13 having a film thickness of 20 nm is formed on the glass substrate 1 by sputtering, and a film having a film thickness of 100 is formed on the other surface of the glass substrate 1.
The second reflective layer 6 made of Al having a thickness of nm is formed by sputtering.

Next, as shown in FIG. 10, the second reflective layer 6 is wet-etched with diluted nitric acid using a photoresist mask (not shown).
A pinhole group 7 is formed in the. The diameter of the formed pinhole 7 was 0.5 mm.

Next, as shown in FIG. 11, a transparent glass stamper 1 having a recess 15 corresponding to the condenser lens group is formed.
6 is filled with the uncured ultraviolet curable resin 17 and is aligned so that the center position of the opening of the depression 15 corresponding to each condensing lens group and the position of the pinhole 7 are aligned, as shown in FIG. By bringing the transparent glass stamper 16 and the glass substrate 1 into close contact with each other, irradiating the ultraviolet light 18 through the transparent glass stamper 16 to cure the ultraviolet curable resin 17, and then peeling off the transparent glass stamper 16.
A thin film solar cell having the condenser lens group 9 of the first embodiment is completed. The condensing lens of the thin-film solar cell of Example 1 manufactured here is one in which the condensing lens groups 9 are regularly arranged in the same phase vertically and horizontally, as shown in FIG. The diameter of the condenser lens 9 is 10 mm, and the lens surface is
It was spherical with the center position of the pinhole 7 as the center.

[0047] For comparison, in the state shown in FIG. 8, SnO ₂
A thin-film solar cell having a conventional structure in which the thickness of the transparent conductive layer 2 was 100 nm was simultaneously prepared. Here, the reason for setting the thickness of the SnO ₂ transparent conductive layer 2 to 100 nm is that the transparent conductive layer 2
This is to maximize the photoelectric conversion efficiency in the conventional thin-film solar cell due to the antireflection effect of the above.

AM1.5 for the thin film solar cell of Example 1 and the conventional thin film solar cell manufactured according to the above method.
Irradiate 100 mW / cm ² of light with a simulator,
When the -V characteristic was measured, it was confirmed that the open-circuit voltage of the thin-film solar cell of Example 1 was about 12% greater and the short-circuit current was about 6% greater than the conventional thin-film solar cell. Therefore, it was found that the thin film solar cell of Example 1 had a photoelectric conversion efficiency of about 19% higher than that of the conventional thin film solar cell.

The thin-film solar cell of Example 2 Example 2 in the same manner as in Example 1, but is produced in substantially the same process as 8-12, as shown in FIG. 4, the condenser lens group 9 They are arranged so that they are in the closest state.

For the thin film solar cell of the second embodiment and the thin film solar cell of the first embodiment, an AM1.5 simulator
When the IV characteristics were measured by irradiating with light of 00 mW / cm ² , the thin film solar cell of Example 2 had an open circuit voltage of about 3% larger than that of the thin film solar cell of Example 1, and a short circuit current. It was confirmed that it was increased by about 3%. Therefore, it was found that the thin film solar cell of Example 2 had a photoelectric conversion efficiency of about 6% higher than that of the thin film solar cell of Example 1.

Example 3 The thin film solar cell of Example 2 was irradiated with light of 100 mW / cm ² by an AM1.5 simulator as shown in FIGS. 5 and in FIG. 5, a direction 11 (indicated by an arrow 11) in which the condenser lens groups 9 are continuously arranged on a straight line.
And a point where two condensing lenses 92 and 93 adjacent to a specific condensing lens 91 and adjacent to each other are in contact with each other,
When the IV characteristic was measured by irradiating from the direction 12 (indicated by the arrow 12) of a straight line connecting the center point of the specific condenser lens 91, the direction 11 was observed when irradiating from the direction 12.
It was confirmed that the open-circuit voltage was about 5% higher and the short-circuit current was about 5% higher than the case of irradiation. Therefore, the photoelectric conversion efficiency is 10% higher when irradiated from the direction 12 than when irradiated from the direction 11.
I found that it was getting higher. From this result, in the morning and in the evening, the direction in which light is obliquely incident, that is, the east-west direction, is adjacent to a specific condenser lens 91, and
More efficient light collection is achieved by matching the point where two adjacent light collecting lenses 92 and 93 are in contact with each other and the direction 12 of the straight line connecting the center point of the specific light collecting lens 91. It was confirmed that it is possible to obtain a thin film solar cell with high power generation efficiency.

Example 4 Next, a thin film solar cell having the tandem structure of the present invention shown in FIG. 2 was produced.

In the fourth embodiment, the thin film photoelectric conversion layer 3
Except for Nos. 1, 32 and 33, it was formed in the same manner as in the first embodiment.

The thin film photoelectric conversion layers 31, 32 and 33 are respectively composed of SiH ₄ gas, H ₂ gas, CH ₄ gas and B ₂ H _6.
A film with a film thickness of 10 nm obtained by vapor phase growth using a mixed gas of gases
-SiC: p layer of the H, the SiH ₄ gas · _H vapor grown film thickness 60nm with ₂ gas mixed gas of a-Si: i layer of H, the SiH ₄ gas · _{H 2} gas · PH ₃ gas N of a-Si: H with a film thickness of 10 nm that was vapor-grown using a mixed gas
It has a pin structure composed of layers and was formed by repeating vapor phase growth by plasma CVD.

For the thin film solar cell of the fourth embodiment having the tandem structure of the present invention and the thin film solar cell of the first embodiment,
When the IV characteristic was measured by irradiating light of 100 mW / cm ^{2 with} an AM1.5 simulator, the thin film solar cell of the fourth example had an open circuit voltage of 60 as compared with the thin film solar cell of the first example. %, And the short-circuit current was reduced by about 20%. That is, it was found that the thin film solar cell of the fourth example had a photoelectric conversion efficiency of about 28% higher than that of the thin film solar cell of the first example.

In Example 4, the thin film photoelectric conversion layer 3
1, 32, and 33 are formed under the same conditions, but the film thickness of each thin film photoelectric conversion layer is optimized, and further, the semiconductor type of each thin film photoelectric conversion layer is changed to perform photoelectric conversion. By shifting the wavelength of the light used for
It is possible to realize a higher photoelectric conversion efficiency.

Although the term hemispherical lens is used in the above-mentioned embodiments and examples, the hemisphere is not limited to a hemisphere in a strict sense obtained by cutting a sphere along a plane passing through the center, and a sphere is a plane. It is a concept that includes cut shapes.

[0058]

As is apparent from the above, according to the thin-film solar cell of the present invention, the light that is condensed by the condenser lens group and is incident from the pinhole group of the second reflective film is the first reflected light. Multiple reflections are made between the layer and the second reflective layer,
Since the thin film photoelectric conversion layer existing between the second reflective layer and the second reflective layer is repeatedly irradiated, the amount of light irradiated to the thin film photoelectric conversion layer increases, and the power generation efficiency increases.

In one embodiment, the thin film photoelectric conversion layer is
Since it is made of an amorphous semiconductor and has a pin structure,
It has the advantages that it has a high absorption coefficient, is thin, can be manufactured inexpensively, and has a relatively high photoelectric conversion efficiency.

In addition, since one embodiment has a tandem structure in which a plurality of thin film photoelectric conversion layers are laminated, the open circuit voltage of the solar cell can be increased. Further, by making the band gaps of the plurality of thin film photoelectric conversion layers different, it is possible to efficiently photoelectrically convert light of each wavelength in each thin film photoelectric conversion layer. Therefore, the above embodiment is
Power generation efficiency can be increased.

In one embodiment, the condensing lens is a hemispherical lens, and the hemispherical lens is arranged so that the center of the hemispherical lens substantially overlaps with the center of the pinhole of the second reflecting layer. Since the group is mounted on the second reflective layer, the hemispherical lens efficiently collects the incident light on the pinhole of the second reflective layer, thus increasing the power generation efficiency. You can

Further, in one embodiment, since the condenser lens is formed of the ultraviolet curing resin, the condenser lens group can be collectively formed by a simple method such as the 2P method. Cost reduction can be realized.

In one embodiment, the condensing lens group is in a close-packed state in which six hemispherical lenses are in contact with each one hemispherical lens, so that the total condensing lens group is formed. The area can be increased, and the power generation efficiency can be increased.

Further, the method of installing a thin film solar cell of the present invention is such that the thin film has a condensing lens group in a close-packed state in which six hemispherical lenses are in contact with each one hemispherical lens. A straight line connecting the solar cell adjacent to a specific hemispherical lens and the point where two hemispherical lenses adjacent to each other contact each other and the center point of the specific hemispherical lens face substantially east-west direction. The hemispherical lenses are not in direct contact with the adjacent hemispherical lenses in the east-west direction even in the morning and evening when the light is incident from the east-west direction and the oblique direction. Since there is a space between the hemispherical lenses, each hemispherical lens can receive a large amount of light even in the morning and evening when the light is incident in the east-west direction and obliquely. Therefore, in the morning and evening Also, it is possible to maintain a high power generation efficiency.

[Brief description of drawings]

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

FIG. 2 is a cross-sectional view of a thin film solar cell according to an embodiment of the present invention.

FIG. 3 is a plan view of the thin-film solar cell according to the embodiment of the present invention.

FIG. 4 is a plan view of a thin-film solar cell according to an embodiment of the present invention.

FIG. 5 is a plan view of the thin-film solar cell according to the embodiment of the present invention.

FIG. 6 is a cross-sectional view of a thin film solar cell according to an embodiment of the present invention.

FIG. 7 is a cross-sectional view of a thin film solar cell according to an embodiment of the present invention.

FIG. 8 is a cross-sectional view illustrating a method of manufacturing a thin film solar cell according to an example of the present invention.

FIG. 9 is a cross-sectional view illustrating a method of manufacturing a thin film solar cell according to an example of the present invention.

FIG. 10 is a cross-sectional view illustrating a method for manufacturing a thin-film solar cell according to an example of the present invention.

FIG. 11 is a cross-sectional view illustrating a method for manufacturing a thin film solar cell according to an example of the present invention.

FIG. 12 is a cross-sectional view illustrating a method of manufacturing a thin film solar cell according to an example of the present invention.

FIG. 13 is a cross-sectional view of a conventional thin film solar cell.

FIG. 14 is a cross-sectional view of a conventional thin film solar cell.

[Explanation of symbols]

1 transparent substrate 2 Transparent conductive film 3 Thin film photoelectric conversion layer 4 Transparent conductive film 5 First reflective layer 6 Second reflective layer 7 pinholes 8 light 9 Focusing lens group 10 Reflection area

Claims (7)

[Claims] 1. A transparent substrate, a first reflective layer located on one surface side of the transparent substrate, and a thin film photoelectric conversion located between the one surface of the transparent substrate and the first reflective layer. A second reflection layer provided on the other surface of the transparent substrate and having a pinhole group, and a condenser lens group for condensing incident light on the pinhole group. Thin film solar cell. 2. The thin-film solar cell according to claim 1, wherein the thin-film photoelectric conversion layer comprises a p-type impurity-doped amorphous semiconductor layer and an n-type impurity-doped amorphous semiconductor layer. A thin film solar cell comprising a pin structure sandwiching i layers, which are layers. 3. The thin film solar cell according to claim 1, wherein the thin film photoelectric conversion layer has a tandem structure in which a plurality of thin film photoelectric conversion layers are laminated. 4. The thin-film solar cell according to claim 1, wherein the condenser lens is a hemispherical lens, and the center of the hemispherical lens is the pinhole provided in the second reflective layer. A thin-film solar cell, wherein the hemispherical lens group is mounted on the second reflective layer so as to substantially overlap the center. 5. The thin-film solar cell according to claim 1, wherein the condenser lens is made of an ultraviolet curable resin. 6. The thin-film solar cell according to claim 4, wherein the condenser lens group is in a close-packed state in which six hemispherical lenses are in contact with each one hemispherical lens. A thin film solar cell characterized by. 7. The thin-film solar cell according to claim 6, wherein two hemispherical lenses adjacent to the specific hemispherical lens and adjacent to each other are in contact with each other, and A method of installing a thin-film solar cell, characterized in that the straight line connecting the center points of the lenses is installed so as to face approximately east-west.