JP2003110130A - Thin film solar battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin film solar battery capable of raising power generating efficiency by not reducing a light quantity incident to a photoelectric conversion layer even when surface reflecting light exists. SOLUTION: Light beams are condensed by the second reflecting surface group 13 of the side face of the pyramid 15 of an optical condensing reflecting element 200, and incident from a light permeable group 10 to the thin film solar cell element 100. The incident light is multiple-reflected between the first reflecting surface group 11 of the bottom of the pyramid 15 of the element 200 and the solar cell element 100. Accordingly, the light quantity illuminated to the conversion layer of the element 100 is increased, thereby raising the power generating efficiency.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a thin film solar cell.

[0002]

2. Description of the Related Art Conventionally, as a thin film solar cell, as shown in FIG. 23, a thin film polycrystalline Si solar cell that performs photoelectric conversion by a pn junction, and as shown in FIG. 24, a thin film that performs photoelectric conversion by a pin junction. There are amorphous Si solar cells.

The thin film polycrystalline Si solar cell shown in FIG.
An electrode metal layer 232 having a light reflecting effect, a polycrystalline Si thin film semiconductor layer 233 doped with one conductivity type impurity at a high concentration, and the same as the polycrystalline Si thin film semiconductor layer 233 are formed on a substrate 231 which also serves as a support. -Type polycrystalline Si thin-film semiconductor layer 234 slightly doped with an impurity of a conductivity type, polycrystalline-Si thin-film semiconductor layer 235 doped with an impurity of a conductivity type opposite to that of said polycrystalline-Si thin-film semiconductor layers 233, 234 at a high concentration, and current is taken out. Collecting electrode 236 for
An antireflection layer 237 for efficiently taking in light is laminated. The polycrystalline Si thin film semiconductor layer 233 doped with the above impurities at a high concentration is the electrode metal layer 232.
And plays a role of improving electrical connection between the polycrystalline Si thin film semiconductor layer 234.

In the thin film amorphous Si solar cell shown in FIG. 24, an electrode metal layer 242 having a light reflecting effect, an amorphous semiconductor, and an n-type impurity are doped on a substrate 241 which also serves as a support. An n layer 243, an i layer 244 made of an amorphous semiconductor and an intrinsic semiconductor, a p layer 245 made of an amorphous semiconductor and doped with p-type impurities, a current collecting electrode 246 for extracting a current, and an efficient Is formed by laminating an antireflection layer 247 for taking in light.

In order to improve power generation efficiency, a tandem structure thin film solar cell in which a pn junction made of a polycrystalline semiconductor shown in FIG. 23 and a pin junction made of an amorphous semiconductor shown in FIG. 24 are laminated is proposed. ing.

In addition to these thin film solar cells, as shown in FIG. 25, a thin film solar cell in which light is incident from the substrate side has been proposed. This thin-film solar cell comprises a transparent substrate 251, an antireflection layer 252 for efficiently taking in light, a collector electrode 253 for taking out an electric current, and ap layer made of an amorphous semiconductor and doped with p-type impurities. 254, i layer 255 made of an amorphous semiconductor which is an intrinsic semiconductor, and n layer 25 made of an amorphous semiconductor and doped with an n-type impurity
6 and an electrode metal layer 257 having a light reflection effect are laminated.

[0007]

In the thin film solar cells shown in FIGS. 23, 24 and 25, the antireflection layer 23 is formed on the light incident surface side for the purpose of suppressing surface reflection as much as possible.
Although 7, 247 and 252 are provided, it is difficult to completely reduce the surface reflection to zero. Further, the antireflection layer 23
7, 247 and 252 generally have wavelength dependence, and there is a problem that surface reflection increases due to deviation of the light wavelength from the design wavelength center. In a tandem structure thin-film solar cell that uses light of a relatively wide wavelength for photoelectric conversion, the adverse effect is even greater.
Further, since the current is taken out, the collector electrodes 236, 246, 253 provided on the light incident side surely bring about a decrease in power generation efficiency.

Further, the polycrystalline Si semiconductor layer 234 and the amorphous semiconductor i layers 244 and 255, which absorb light to generate charges and generate electric power, need to have sufficient film thickness to absorb incident light. However, if the thickness is too thick, the traveling distance of the charges increases, and the current that can be taken out to the outside decreases. In addition, these semiconductor layers 234, 244, 255
The increase in the film thickness of (3) leads to an increase in manufacturing time and an increase in the amount of material used, which makes cost reduction difficult.

Therefore, an object of the present invention is to provide a thin-film solar cell capable of increasing power generation efficiency without reducing the amount of light incident on the photoelectric conversion layer even if there is surface-reflected light. is there.

[0010]

In order to solve the above problems, a thin film solar cell of the present invention is provided with a thin film solar cell element having a photoelectric conversion layer, a transparent substrate, and one surface of this transparent substrate. The light incident on the thin-film solar cell element is provided with a condensing reflection element having a first reflection surface group having a light transmission hole group and a second reflection surface group having an incident light condensed on the light transmission hole. The other surface of the transparent substrate of the light collecting and reflecting element is opposed to the surface, and the light collecting and reflecting element is attached to the thin film solar cell element.

According to the above structure, the incident light is condensed on the light transmitting hole group by the second reflecting surface group of the light collecting and reflecting element. Then, the light from the light transmitting hole passes through the transparent substrate and enters the thin film solar cell element, and is multiplexed between the thin film solar cell element and the first reflecting surface group of the condensing reflecting element. Is reflected. Therefore, the incident light is condensed by the second reflecting surface group and passed through the light transmitting hole, and the light passing through the light transmitting hole is effectively used without being escaped by the first reflecting surface group. Is multiply reflected between the first reflective surface group of the condensing reflective element and the thin-film solar cell element, and the synergistic effect with the point of irradiating the photoelectric conversion layer causes the light irradiating the photoelectric conversion layer. The amount of light increases remarkably and the power generation efficiency becomes extremely high.

In one embodiment, the second reflecting surface group of the light converging / reflecting element is a flat inclined surface group inclined with respect to the one surface of the transparent substrate, and the light transmitting hole group. Located on both sides of.

In the above-mentioned embodiment, since the second reflecting surface group of the light converging / reflecting element is a flat inclined surface group inclined with respect to the one surface of the transparent substrate, it is a curved surface group. The structure is simple compared to. Further, since the second reflecting surface group is located on both sides of the light transmitting hole group, it is possible to effectively collect light.

Further, in one embodiment, the first reflecting surface group of the light collecting and reflecting element is a reflecting film provided on the bottom surfaces of a plurality of triangular prisms, and the second film of the second light collecting and reflecting element is formed. The reflective surface group is a reflective film provided on the side surfaces of the plurality of triangular prisms, and the bottom surface of the triangular prism is fixed to the one surface of the transparent substrate via the first reflective surface. .

According to the above-mentioned embodiment, a first method for condensing light is provided on the transparent substrate by a simple method such as fixing the bottom surface of the triangular prism having the bottom surface and the side surface with reflective films formed thereon. It is possible to form a condensing reflective element having two reflective surface groups and a first reflective surface group for multiple reflection. Therefore, cost reduction of a highly efficient thin film solar cell can be realized.

In one embodiment, the base angle of the triangle, which is the cross section of the triangular prism, is 67.5 degrees or more.

According to the above-mentioned embodiment, since the base angle of the triangle which is the cross section of the triangular prism is 67.5 degrees or more, the light transmitting hole is formed by the second reflecting surface provided on the side surface of the triangular prism. It is possible to collect the incident light on.

Further, in one embodiment, the triangle which is the cross section of the triangular prism is an isosceles triangle, and the isosceles 3 thereof.
The angle of the prism is less than 45 degrees.

According to the above embodiment, the apex angle of the isosceles triangle, which is the cross section of the triangular prism, is smaller than 45 degrees.
Even if the sun is not directly above, it can be effectively condensed by the second reflecting surface. Therefore, the amount of light with which the photoelectric conversion layer of the thin film solar cell is irradiated is increased, and power generation efficiency can be increased.

In one embodiment, the apex angle of the isosceles triangle is smaller than 30 degrees.

According to the above embodiment, since the apex angle of the isosceles triangle is smaller than 30 degrees, the second reflecting surface can collect light more effectively even if the sun is not directly above. it can. Therefore, the amount of light with which the photoelectric conversion layer of the thin film solar cell is irradiated is further increased, and the power generation efficiency can be further increased.

Further, in one embodiment, a transparent substrate having a fluorescent property is installed between the light converging / reflecting element and the thin film solar cell element.

According to the above-described embodiment, the light condensed by the second reflecting surface group of the condensing / reflecting element and passing through the light transmitting hole is incident on the transparent substrate having the fluorescent property, and the fluorescent light is emitted. The transparent substrate having the characteristics converts light in a wavelength range that cannot be used for photoelectric conversion into light in a wavelength range that can be used for photoelectric conversion, and randomly radiates and scatters the light. The light radiated and scattered by the transparent substrate having the fluorescent property and converted into light in the wavelength range that can be used for photoelectric conversion is the first reflection surface group of the condensing reflection element, the thin film solar cell element, and the like. Multiple reflections are made between. Therefore, the second of the condensing reflection element
The point that the light that has been condensed by the reflective surface group and has passed through the light transmission hole once is not escaped by the first reflective surface group and is effectively used, and the wavelength that cannot be used for photoelectric conversion due to the transparent substrate having the fluorescent property. Point light is converted into light in a wavelength range that can be used for photoelectric conversion, and light is multiply reflected between the thin film solar cell element and the first reflection surface and is applied to the photoelectric conversion layer, Due to the synergistic effect of the transparent substrate having multiple reflection and fluorescence characteristics, the light in the wavelength range that cannot be used for photoelectric conversion becomes light in the wavelength range that can be used for photoelectric conversion, and the photoelectric conversion layer is irradiated with the light. The light amount of the light in the wavelength range that contributes to the photoelectric conversion irradiated to the remarkably increases, and the power generation efficiency becomes extremely high.

Further, in one embodiment, the substrate of the thin film solar cell element is a transparent substrate having a fluorescent property.

In the above embodiment, since the substrate of the thin film solar cell element is a transparent substrate that functions as a fluorescent layer,
Light incident from the group of light transmitting holes, and light converted into light in a wavelength range that can be used for photoelectric conversion from light in a wavelength range that cannot be used for photoelectric conversion by the transparent substrate having the fluorescent property,
Multiple reflection occurs between the thin-film solar cell element and the first reflecting surface group of the condensing reflecting element. Therefore, the amount of light in the wavelength range that contributes to photoelectric conversion applied to the photoelectric conversion layer is increased, and power generation efficiency can be increased.

Further, in one embodiment, the transparent substrate of the light converging / reflecting element has a fluorescent characteristic.

In the above-described embodiment, since the transparent substrate of the light converging / reflecting element functions as a fluorescent layer, the light incident from the group of light transmitting holes and the wavelengths that cannot be used for photoelectric conversion due to the transparent substrate having the fluorescent property. The light converted into the light in the wavelength range that can be used for photoelectric conversion is multiple-reflected between the thin-film solar cell element and the first reflecting surface group of the condensing reflecting element. Therefore, the amount of light in the wavelength range that contributes to photoelectric conversion applied to the photoelectric conversion layer is increased, and power generation efficiency can be increased.

In one embodiment, the thin film solar cell element and the condensing reflection element are mechanically fixed via a spacer.

According to the above-mentioned embodiment, since the light collecting and reflecting element is mechanically fixed to the thin film solar cell element through the spacer, the light collecting and reflecting element can be simply attached to the thin film solar cell element. Can be installed. Further, the thin-film solar cell of the above-described embodiment can be configured by simply attaching the condensing reflection element to the conventional thin-film solar cell, and easily improve the power generation efficiency of the conventional thin-film solar cell. It becomes possible to do. Further, the thin-film solar cell element and the light-collecting and reflecting element can be easily separated and replaced with each other. Further, the thin film solar cell element can be protected by the light converging and reflecting element to improve the reliability of the thin film solar cell.

Further, in one embodiment, the thin-film solar cell element, the transparent substrate having the fluorescent property, and the condensing reflection element are mechanically fixed via a spacer.

In the above embodiment, the thin film solar cell element, the transparent substrate having the fluorescent characteristic, and the light converging / reflecting element are mechanically fixed through the spacer,
They can be easily fixed, and they can be easily disassembled and replaced. Further, with respect to the conventional thin-film solar cell, the transparent substrate having the fluorescent property and the condensing reflection element can be easily attached to easily configure the thin-film solar cell of the above-described embodiment, It is possible to easily improve the power generation efficiency of the thin film solar cell. Further, the thin film solar cell element and the transparent substrate having the fluorescent property can be protected by the light converging and reflecting element to improve the reliability of the thin film solar cell.

Further, in one embodiment, the thin film solar cell element, the transparent substrate having the fluorescent property, and the condensing reflection element are fixed by an adhesive.

In the above embodiment, since the thin film solar cell element, the transparent substrate having the fluorescent property, and the light converging / reflecting element are fixed by the adhesive, they can be fixed easily and firmly. It is possible to obtain a highly reliable thin film solar cell having excellent environment resistance. Further, when the adhesive is a transparent adhesive, the appearance does not deteriorate even if the adhesive is squeezed out.

In one embodiment, the thin film solar cell element and the light collecting and reflecting element are fixed by an adhesive.

In the above embodiment, since the thin film solar cell element and the light collecting and reflecting element are fixed by the adhesive, they can be fixed easily and firmly, and the environment resistance is excellent and the reliability is high. A high thin film solar cell can be obtained.
Further, when the adhesive is a transparent adhesive, the appearance does not deteriorate even if the adhesive is squeezed out.

Further, in one embodiment, the adhesive is a transparent adhesive having a fluorescent property.

In the above embodiment, since the adhesive is a transparent adhesive having a fluorescent property, the transparent adhesive is
In addition to having the function of connecting the condensing reflection element and the thin-film solar element, it also functions as a fluorescent layer that enhances photoelectric conversion efficiency by converting light in the wavelength range that cannot be used for photoelectric conversion into light in the wavelength range that can be used for photoelectric conversion. Have.

Further, in one embodiment, the thin-film solar cell element includes a reflective layer located on the side opposite to the light incident surface with respect to the photoelectric conversion layer.

In the above-mentioned embodiment, since the photoelectric conversion layer is located between the reflection layer of the thin-film solar cell element and the incident surface, the reflection layer of the thin-film solar cell element and the condensing reflection element The photoelectric conversion layer and the fluorescent layer are sandwiched between the first reflective surface and the first reflective surface of the thin film solar cell element and the first condensing reflective element.
The light is multiple-reflected between itself and the reflecting surface. Therefore, the amount of light in the wavelength region that contributes to photoelectric conversion applied to the photoelectric conversion layer is significantly increased, and the power generation efficiency can be extremely increased.

[0040]

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

(Embodiment 1) FIG. 1 shows a cross-sectional view of a thin film solar cell according to Embodiment 1 of the present invention, and FIG.
The cross-sectional perspective view of the thin film solar cell of Embodiment 1 of this invention is shown.

The thin film solar cell is a thin film solar cell element 1
00 and the condensing reflection element 200.

The thin-film solar cell element 100 comprises a substrate 1 also serving as a support, an electrode metal layer 2 as a reflection layer having a light reflection effect, and a polycrystal doped with a high concentration of one conductivity type impurity. Si thin film semiconductor layer 3 and this polycrystalline S
i The polycrystalline Si thin film semiconductor layer 4 slightly doped with the same type of impurity as the thin film semiconductor layer 3, and the polycrystalline Si thin film semiconductor layer 3 and the polycrystalline Si thin film semiconductor layers 3 and 4 doped with a conductivity type impurity at a high concentration. A thin film semiconductor layer 5, a current collecting electrode 6 for taking out an electric current, and an antireflection layer 7 for taking in light efficiently are sequentially laminated. The polycrystalline Si thin film semiconductor layers 3, 4, 5 constitute an example of a photoelectric conversion layer.
Note that polycrystalline Si doped with the above impurities at a high concentration
The thin film semiconductor layer 3 serves to improve the electrical connection between the electrode metal layer 2 and the semiconductor layer 4.

On the other hand, the condensing reflection element 200 is shown in FIG.
As shown in FIG. 2, the transparent substrate 9 and the first reflecting surface group 11 provided on one surface of the transparent substrate 9 and having the linear light transmitting hole group 10 are incident on the light transmitting hole group 10. The second reflecting surface group 13 is formed on the slope of the triangular prism 15 to collect the light 12. That is, the first reflecting surface 11 and the second reflecting surface 13 are formed of reflecting films formed on the bottom surface and the inclined surface of the triangular prism 15. The triangular prism 15 has an isosceles triangle in cross section, and the apex angle 16 of the isosceles triangle is 4
The angle is set smaller than 5 degrees, and more preferably smaller than 30 degrees. That is, the base angle of the isosceles triangle of the cross section of the triangular prism 15 is (180-45) / 2 = 67.
5 degrees or more, more preferably (180-30) / 2 = 7
It is more than 5 degrees. Instead of the triangular prism 15 having an isosceles triangular cross section, a triangular prism having an isosceles triangular cross section may be used, or a triangular prism having one obtuse angle as a base angle may be used.

As shown in FIG. 1, when the thin film solar cell having the above structure is vertically irradiated with incident light 12 such as sunlight, the incident light 12 is reflected by the second reflecting surface group 13 to emit light. It is incident on the transmission hole group 10. Here, if the above-mentioned slanted surface group forming the second reflective surface 13 is formed with a steeply inclined surface larger than 60 degrees with respect to the transparent substrate 9, it does not enter the light transmission hole group by one reflection. The incident light 12 is also adjacent to the second
The light is reflected by the reflection surface 13 of the above, and finally enters the light transmission hole group 10. Here, since the incident angle of the incident light 12 such as sunlight is not always vertical, it is desirable that the above-mentioned slope group is a steeply sloped surface that makes an angle as large as possible with respect to the transparent substrate 9, and the angle is 67.5. It is preferably at least 75 degrees, and more preferably at least 75 degrees. That is, the apex angle 16 of the cross section of the triangular prism 15 is preferably 45 degrees or less, and more preferably less than 30 degrees.

A group of light transmission holes 10 of the condensing reflection element 200.
The incident light 12 focused on the light passes through the transparent substrate 9 and enters the thin-film solar cell element 100. The light incident on the thin-film solar cell element 100 is reflected by the antireflection layer 7 and polycrystalline Si.
The polycrystalline Si thin film semiconductor layers 5 and 5 are transmitted again through the thin film semiconductor layers 5, 4, and 3 by the electrode metal layer 2 as a reflection layer.
Pass 4 and 3. As a result, the light absorption efficiency in the polycrystalline Si thin film semiconductor layers 5, 4, 3 is improved.

In the thin-film solar cell, the light reflected on the surfaces of the antireflection layer 7, the collector electrode 6, and the polycrystalline Si thin-film semiconductor layer 5 is reflected by the first reflection surface group 11 and again, The light enters the thin film solar cell element 100 and passes through the polycrystalline Si thin film semiconductor layers 5, 4, and 3. In this way, the light incident from the light transmitting hole group 10 is multiply reflected between the first reflecting surface group 11 of the light collecting and reflecting element 200 and the thin-film solar cell element 100, so that a higher light absorption efficiency is obtained. Will be realized.

In the thin-film solar cell, multiple reflection is realized between the first reflective surface group 11 of the condensing reflective element 200 and the electrode metal layer 2 of the thin-film solar cell element 100, so that the polycrystalline structure is obtained. Even when the Si thin film semiconductor layers 4 and 5 are made thin, the incident light is sufficiently absorbed, the traveling distance of charges can be shortened, and the current that can be extracted to the outside can be increased.

(Second Embodiment) In FIG. 1, as a thin film solar cell element 100, a polycrystalline S as shown in FIG. 23 is used.
Although the case of using the i semiconductor layer has been described,
Also in the case of a thin film solar cell element using an amorphous Si semiconductor layer as shown in FIG. 24 and a tandem structure thin film solar cell element using both a polycrystalline Si semiconductor layer and an amorphous Si semiconductor layer. Similar multiple reflections can be realized and the light absorption efficiency can be improved.

FIG. 3 is a sectional perspective view of the thin film solar cell of the second embodiment. The thin film solar cell according to the second embodiment is
The thin-film solar cell element 300 of the type that includes the same light-collecting and reflecting element 200 of the first embodiment shown in FIG. 1 and in which light is incident from the transparent substrate side is the thin-film solar cell shown in FIG. Different from the battery element 100. Therefore, in FIG. 3, the same components as those of the first embodiment shown in FIG. 1 are designated by the same reference numerals as those of the components of FIG. 1, and detailed description thereof will be omitted.

The thin-film solar cell element 300 comprises a transparent substrate 17 made of a glass substrate, an antireflection layer 18 for efficiently taking in light, and a collector electrode 1 for taking out current.
9, p layer 20 made of amorphous semiconductor and doped with p-type impurities, i made of amorphous semiconductor and an intrinsic semiconductor
A layer 21, an n layer 22 made of an amorphous semiconductor and doped with an n-type impurity, and an electrode metal layer 23 as a reflection layer having a light reflection effect are sequentially laminated. The p layer 20, the i layer 21, and the n layer 22 constitute an example of a photoelectric conversion layer.

As shown in FIG. 3, the condensing reflective element 20 is used.
By arranging 0 and the thin film solar cell element 300,
As in the case of FIG. 1, the antireflection layer 18, the collector electrode 19,
The light reflected by the surfaces of the amorphous Si thin film semiconductor layer (p layer) 20 and the electrode metal layer 23 is reflected by the first reflecting surface group 11 of the condensing reflecting element 200, and the thin film solar layer is again displayed. The amorphous Si thin film semiconductor layer 20 is incident on the battery element 300.
Incident on. Thus, the light incident from the light transmitting hole group 10 is multiply reflected between the first reflecting surface group 11 of the condensing reflecting element 200 and the thin film solar cell element 300,
Higher light absorption efficiency is realized.

[0053]

Example 1 According to the process shown in FIGS. 4 to 6, the condensing reflective element 200 of the thin film solar cell according to the first embodiment of the present invention shown in FIGS.

First, as shown in FIG. 4, a polycarbonate resin triangular prism 15 having a cross-section vertical angle 16 of 30 degrees was produced by extrusion molding. Next, as shown in FIG. 5, a film thickness of 100 is formed on the side surfaces 25, 26, 27 of the triangular prism 15.
A reflective film of Al _0.95 Ti _0.05 nm was formed by sputtering. This reflective film is the first reflective surface 11 and the second reflective surface 13 shown in FIG. Then, as shown in FIG. 6, side surfaces (bottom surfaces) of the plurality of triangular prisms 15 are provided.
The plurality of triangular prisms 15 has a thickness of 1
On a glass substrate 9 as a transparent substrate having a size of 10 mm, the linear light transmitting hole groups 10 were adhered at equal intervals with an adhesive. By doing so, the reflective film on the side surface (bottom surface) 25 side of the triangular prism 15 becomes the first reflective surface group 11,
The condensing reflective element 200 in which the reflective films on the side surfaces 26 and 27 of the triangular prism 15 serve as the second reflective surface group 13 is formed.

Here, the cross-sectional shape of the triangular prism 15 is 2
Side surface 25 that is an equilateral triangle and serves as the first reflection surface group 11
Has a length of 10.0 mm, the side surfaces 26 and 27 have a length of 19.3 mm, and the light transmitting hole group 10 has a width of 1.0 mm.
The triangular prism 15 was adhesively fixed to the glass substrate 9 so as to have a size of mm.

In the first embodiment, the condenser reflection element 20 is used.
Although the glass substrate is used as the transparent substrate 9 of No. 0, it is not limited to this as long as it can transmit light. For example, by using an injection-molded polycarbonate resin, a lighter weight and cheaper thin film solar cell can be obtained.

Further, although the AlTi sputtered film is used as the reflective film constituting the first reflective surface group 11 and the second reflective surface group 13, any metal film having a high reflectance may be used.
Besides, a metal film of Al, Ag, Au, Ti, or the like, and an alloy film composed of these metals can be used.
Further, it is desirable that the film thickness of the reflective film is 40 nm or more, at which light is almost completely reflected. However, if the reflective film becomes too thick, the film formation time and the material cost increase, so it is desirable that the thickness be 150 nm or less. Further, in the first embodiment, the reflective film is formed by sputtering, but it is also possible to use a film forming method such as vacuum evaporation. Furthermore, by forming the metal reflective film using an electroforming technique such as electroless plating, a vacuum process for forming the condensing reflective element becomes unnecessary, and the cost of the thin film solar cell can be reduced. It will be possible.

On the other hand, the thin film solar cell element 100 shown in FIG.
Was manufactured by the same method as the conventional method. That is, on the stainless steel substrate 1 which also functions as a support, Al having a film thickness of 100 nm and having a light reflection effect which functions as a reflection layer.
_{After the 0.95} Ti _0.05 electrode metal layer 2 is formed by sputtering, one conductivity type impurity is doped at a high concentration to form a polycrystalline Si thin film semiconductor layer 3 and an impurity of the same type as the polycrystalline Si thin film semiconductor layer 3. A polycrystalline Si thin-film semiconductor layer 4 slightly doped with, and a polycrystalline Si thin-film semiconductor layer 5 heavily doped with an impurity of a conductivity type opposite to those of the polycrystalline Si thin-film semiconductor layers 3 and 4 by plasma CVD (chemical vapor deposition). Phase growth) device. The polycrystalline Si thin film semiconductor layer 3 doped with the above impurities at a high concentration is provided in order to improve the electrical connection between the electrode metal layer 2 and the polycrystalline Si semiconductor layer 4.

More specifically, the polycrystalline Si thin film semiconductor layer 3 has a substrate temperature of 250 ° C. under the condition of SiH ₄ gas and H 2.
A mixed gas in which the mixing ratio of ₂ gas and PH ₃ gas is optimized is C
It was formed by introducing it into a VD apparatus and applying a high frequency power of 100 W at a gas pressure of 20 Pa. Thus
On the electrode metal layer 2, a polycrystalline Si thin film semiconductor film 3 having a film thickness of 30 nm doped with P at a high concentration was deposited.

Next, the polycrystalline Si thin film semiconductor layer 4 is
SiH at a substrate temperature of 550 ° C _FourGas, H_Twogas,
PH_ThreeCVD equipment for mixed gas with optimized gas mixing ratio
And the gas pressure is 50 Pa and the high-frequency power of 350 W is applied.
It was formed by applying force. Thus, the above
P is slightly doped on the crystalline Si thin film semiconductor layer 3.
The polycrystalline Si thin film semiconductor film 4 having a thickness of 150 nm
Piled up.

The polycrystalline Si thin-film semiconductor film 4 is a layer that absorbs light, generates electric charges, and generates electric power. In order to sufficiently absorb light, its thickness is usually 1000 nm or more and 5 nm or more.
Although it is set to 0000 nm or less, in Example 1, since the incident light from the linear light transmitting hole 10 is multiply reflected, it is possible to make the polycrystalline Si thin film semiconductor layer 4 thin. It is desirable that the thickness is 100 nm or more and 2000 nm or less.

Next, the polycrystalline Si thin film semiconductor layer 5 is
SiH at a substrate temperature of 350 ° C _FourGas, H_Twogas,
BF_ThreeCVD equipment for mixed gas with optimized gas mixing ratio
The gas pressure of 50 Pa and high frequency power of 100 W.
It was formed by applying force. Thus, the above
A film doped with B on the crystalline Si thin film semiconductor layer 4
A p-type polycrystalline Si thin film semiconductor film 5 having a thickness of 15 nm is deposited.
It was The polycrystalline Si thin film semiconductor layers 4 and 5 have a pn junction.
Form.

Next, the substrate 1 on which the pn junction of polycrystalline Si is formed in this manner is attached to a sputtering apparatus, and a shielding mask is attached to the surface of the polycrystalline Si thin film semiconductor layer 5 of the substrate 1, and an AlTi alloy target is set. Using film thickness 10
Width 0.1m consisting Al _0.95 Ti _{0. 05} of 0nm
A comb-shaped current collecting electrode 6 having an m of 5 mm was formed.

Then, reactive sputtering is performed in an oxygen atmosphere using an In ₂ O ₃ target to prevent reflection of 65 nm in thickness on the polycrystalline Si thin film semiconductor layer 5 and the comb-shaped collector electrode 6. Layer 7 was formed.

Condensing reflection element 2 manufactured as described above.
00 and the thin film solar cell element 100 were mechanically fixed by a fixing metal fitting 29 via a resin spacer 28 having elasticity as shown in FIG. 7 to complete the thin film solar cell of Example 1.

As described above, the thin film solar cell element 100
Since the light collecting and reflecting element 200 is mechanically fixed by the fixing metal fitting 29 via the resin spacer 28, the light collecting and reflecting element 200 can be easily attached to the thin film solar cell element 100. In addition, the thin film solar cell element 1
00 and the condensing reflection element 200 can be easily separated, and they can be exchanged. Further, the thin-film solar cell element 100 can be protected by the condensing reflection element 200 to improve the reliability of the thin-film solar cell.

Next, a thin film solar cell element was produced in which the thickness of the polycrystalline Si thin film semiconductor film 4 of the thin film solar cell element 100 was 10,000 nm, which is the same as the conventional thin film solar cell, and the thin film solar cell element was assembled. A thin-film solar cell including only the thin-film solar cell element without attaching the light reflecting element 200 was used as a thin-film solar cell of Comparative Example 1.

For the thin-film solar cell of Example 1 and the thin-film solar cell of Comparative Example 1, an AM1.5 simulator was used.
When the IV characteristics were measured by irradiating with light of 00 mW / cm ² , the thin-film solar cell of Example 1 had an open circuit voltage about 10% smaller than that of the thin-film solar cell of Comparative Example 1, and had a short-circuit current. It was confirmed that it was about 55% larger. Therefore, it was found that the thin film solar cell of Example 1 had a photoelectric conversion efficiency of about 40% higher than that of the thin film solar cell of Comparative Example 1.

In Example 1, the polycrystalline Si thin film semiconductor layers 3, 4, and 5 were used as the photoelectric conversion layer, but a pin junction made of an amorphous Si semiconductor can also be used as the photoelectric conversion layer. . Further, although a thin film solar cell in which only one set of photoelectric conversion layers composed of the polycrystalline Si thin film semiconductor layers 3, 4, and 5 is formed is described, in Example 1, the light utilization efficiency is improved by the multiple reflection. Has been improved,
It is possible to thin the polycrystalline Si thin film semiconductor layers 3, 4, 5. Therefore, by stacking a plurality of photoelectric conversion layers composed of these polycrystalline Si thin-film semiconductor layers 3, 4, and 5 to form a tandem structure, a pin junction by an amorphous Si semiconductor layer and a polycrystalline Si semiconductor layer are formed. By stacking multiple pairs of pn junctions into a tandem structure,
Further, it is possible to improve the open circuit voltage.

[0070]

Second Embodiment As shown in FIG. 8, light collection in the first embodiment
Reflective element 200 and Y with a particle size of 5 μm _TwoO_TwoS: Eu, M
Plate thickness 1 containing 20% by volume of g, Ti phosphorescent fluorescent particles
mm fluorescent glass substrate 30 and the thin film thickness in Example 1
The positive battery element 100 and the resin spacer having elasticity
Mechanically fixed by fixing bracket 29 via 28, 28
Then, the thin film solar cell of Example 2 was completed.

Conventionally, a substrate or a film having a fluorescent property is arranged on the light incident surface of a thin film solar cell element, and light having a wavelength near 400 nm which is not used for photoelectric conversion is converted into light having a wavelength near 600 nm which is used for photoelectric conversion. Although it has been proposed to convert the light and improve the power generation efficiency, the incident light is scattered by the substrate or film having a fluorescent property, and the amount of light incident on the thin film solar cell element is reduced, resulting in a large photoelectric conversion. There was a problem that the improvement in efficiency could not be realized. Furthermore, a wavelength of 600 nm emitted from a substrate or film having fluorescent properties
Since the emission direction of the light in the vicinity is random, half of the light in the vicinity of the wavelength of 600 nm emitted from the substrate or film having the fluorescent property is emitted in the direction opposite to the thin film solar cell element and does not contribute to photoelectric conversion. There was such a problem.

Therefore, as shown in FIG. 8, the fluorescent glass substrate 30 is provided between the condensing reflection element 200 and the thin-film solar cell element 100, so that the fluorescent glass substrate 30 is provided.
The light scattered by the fluorescent particles in the inside and the light emitted from the fluorescent particles are multiply reflected between the first reflective surface group 11 of the condensing reflective element 200 and the thin film solar cell element 100. Then, most of the incident light and the light emitted from the fluorescent particles are incident on the thin film solar cell element 100, and the photoelectric conversion efficiency of the thin film solar cell can be enhanced.

For the thin-film solar cell of Example 2 and the thin-film solar cell of Comparative Example 1, an AM1.5 simulator was used.
When the IV characteristics were measured by irradiating with light of 00 mW / cm ² , the thin-film solar cell of Example 2 had almost the same open circuit voltage and a short-circuit current of 7 as compared with the thin-film solar cell of Comparative Example 1.
It was confirmed that it was increased by about 5%. Therefore,
It was found that the thin film solar cell of Example 1 had a photoelectric conversion efficiency of about 75% higher than that of the thin film solar cell of Comparative Example 1.

In Example 2, the polycrystalline Si thin film semiconductor layers 3, 4, and 5 were used as the photoelectric conversion layer, but it is also possible to use a pin junction made of an amorphous Si semiconductor as the photoelectric conversion layer. . Further, although a thin film solar cell in which only one set of photoelectric conversion layers composed of polycrystalline Si thin film semiconductor layers 3, 4, and 5 is formed is described, in the second embodiment, light utilization efficiency is improved by multiple reflection. Has been improved,
It is possible to thin the polycrystalline Si thin film semiconductor layers 3, 4, 5. Therefore, by stacking a plurality of photoelectric conversion layers composed of these polycrystalline Si thin-film semiconductor layers 3, 4, and 5 to form a tandem structure, a pin junction by an amorphous Si semiconductor layer and a polycrystalline Si semiconductor layer are formed. By stacking multiple pairs of pn junctions into a tandem structure,
Further, it is possible to improve the open circuit voltage.

In the second embodiment, the phosphorescent particles of Y ₂ O ₂ S: Eu, Mg, Ti having a particle diameter of 5 μm are used as the phosphor particles, but the phosphor particles are not limited thereto.

For example, the fluorescent particles have a particle size of 2 to 20 μm.
It is possible to absorb light having a wavelength of 200 to 450 nm and emit light having a wavelength of 625 nm by using the phosphorescent fluorescent particles of Y ₂ O ₂ S: Eu, Mg, Ti of m. Further, by using oxyfluoride-based crystallized glass containing Er ³⁺ ions, it is possible to absorb light having a wavelength of around 800 nm and emit light having a wavelength of 550 to 660 nm.

As fluorescent materials other than the above, compounds containing strontium oxide and aluminum oxide are added to the rare earth elements europium (Eu) and dysprosium (D).
y) added SrAl ₂ O ₄ : Eu, Dy and Sr ₄
Al ₁₄ O ₂₅ : Eu, Dy and CaAl ₂ O ₄ : E
It is possible to use fluorescent materials such as u, Dy and ZnS: Cu.

[0078]

[Third Embodiment] FIG. 9 shows a cross-sectional view of a thin-film solar cell according to a third embodiment.

In the third embodiment, the thin film solar cell element 100 manufactured in the first embodiment and the condensing reflection element 200 are used.
And a transparent acrylic adhesive 31. Here, the thickness of the acrylic transparent adhesive 31 was set to 0.1 mm. With such a structure, the environment resistance can be improved.

The thin film solar cells of Examples 1 and 3 were subjected to an environmental test at 80 ° C. and 80% relative humidity for 2 months. In the thin film solar cells of Example 1, the resin spacer 28 was used. From this part, high-humidity atmosphere entered between the condensing reflection element 200 and the thin film solar cell element 100, the corrosion of the thin film solar cell element 100 started, and the power generation efficiency decreased by 20%. On the other hand, the thin film solar cell of Example 3 laminated with the acrylic transparent adhesive 31 is
It was confirmed that there was no change in appearance and no decrease in power generation efficiency, and that it had excellent environmental resistance.

[0081]

Fourth Embodiment FIG. 10 shows a cross-sectional view of the thin film solar cell of the fourth embodiment.

In the fourth embodiment, the thin film solar cell element 100 used in the second embodiment, the fluorescent glass substrate 30 having a plate thickness of 1 mm, and the condensing reflection element 200 are bonded together by an acrylic transparent adhesive 31. Has become.
Here, the thickness of the acrylic transparent adhesive 31 is 0.1 mm.
And With such a structure, the environment resistance can be improved.

The thin film solar cells of Examples 2 and 4 were subjected to an environmental test at 80 ° C. and 80% relative humidity for 2 months. In the thin film solar cells of Example 2, the resin spacer 28 was used. From this part, the high-humidity atmosphere entered between the condensing reflection element 200, the fluorescent glass substrate 30 and the thin film solar cell element 100, the thin film solar cell element 100 started to corrode, and the power generation efficiency decreased by 25%. . On the contrary,
Example 4 laminated with an acrylic transparent adhesive 31
It was confirmed that the thin-film solar cell of No. 1 had excellent environmental resistance without any change in appearance or reduction in power generation efficiency.

[0084]

[Embodiment 5] FIG. 11 shows a cross-sectional view of a thin-film solar cell of Embodiment 5.

In Example 5, the thin-film solar cell element 100 produced in Example 1 and the condensing reflection element 200 were used.
And a fluorescent acrylic transparent adhesive 32 containing 20% by volume of Y ₂ O ₂ S: Eu, Mg, and Ti phosphorescent fluorescent particles having a particle diameter of 5 μm. Here, the thickness of the fluorescent acrylic transparent adhesive 32 is set to 0.5.
mm. Also in the configuration of Example 5, the fluorescent acrylic transparent adhesive 32 containing the fluorescent particles has a wavelength near 400 nm which is not used for photoelectric conversion, like the fluorescent glass substrate 30 shown in Examples 2 and 4. The light is converted into light having a wavelength near 600 nm which is used for photoelectric conversion, and improvement in power generation efficiency is realized.

For the thin-film solar cell of Example 5 and the thin-film solar cell of Comparative Example 1, an AM1.5 simulator was used.
When the IV characteristics were measured by irradiating with light of 00 mW / cm ² , the thin-film solar cell of Example 1 had an open circuit voltage of about 5% smaller than that of the thin-film solar cell of Comparative Example 1, and had a short-circuit current. It was confirmed that it was about 70% larger. Therefore, it was found that the thin film solar cell of Example 1 had a photoelectric conversion efficiency of about 62% higher than that of the thin film solar cell of Comparative Example 1.

In Example 5, the polycrystalline Si thin film semiconductor layers 3, 4, and 5 were used as the photoelectric conversion layer, but a pin junction made of an amorphous Si semiconductor can also be used as the photoelectric conversion layer. . Further, although a thin film solar cell in which only one set of photoelectric conversion layers composed of the polycrystalline Si thin film semiconductor layers 3, 4, and 5 is formed is described, in the fifth embodiment, the light utilization efficiency is improved by the multiple reflection. Has been improved,
It is possible to thin the polycrystalline Si thin film semiconductor layers 3, 4, 5. Therefore, by stacking a plurality of photoelectric conversion layers composed of these polycrystalline Si thin-film semiconductor layers 3, 4, and 5 to form a tandem structure, a pin junction by an amorphous Si semiconductor layer and a polycrystalline Si semiconductor layer are formed. By stacking multiple pairs of pn junctions into a tandem structure,
Further, it is possible to improve the open circuit voltage.

[0088]

[Sixth Embodiment] FIG. 12 shows a cross-sectional view of a thin-film solar cell of a sixth embodiment.

Example 6 is an example relating to the thin-film solar cell of Embodiment 2 shown in FIG. The light collecting and reflecting element 200 and the thin film solar cell element 300 in FIG. 12 have the same configurations as the light collecting and reflecting element 200 and the thin film solar cell element 300 of the second embodiment shown in FIG.

As shown in FIG. 3, the thin-film solar cell element 300 has a SnO film with a thickness of 30 nm formed on a glass substrate 17.
_{2 After the} transparent conductive layer 18 is formed by reactive sputtering, the substrate 17 is attached to the sputtering apparatus, and the shielding mask is mounted on the surface of the transparent conductive layer 18 of the substrate 17, and an AlTi alloy target is used to form an Al film having a thickness of 100 nm. Width 0.1 mm made of _0.95 Ti _0.05 , spacing 5
A mm-shaped current collecting electrode 19 was formed.

Next, the p-type impurity-doped semiconductor layer p
A photoelectric conversion layer in which a layer 20, an i layer 21 that is an intrinsic semiconductor, and an n layer 22 that is an n-type impurity doped layer were stacked in this order was formed by a vapor phase growth method using a plasma CVD apparatus. Each of the semiconductor layers 20, 21, and 22 is made of a-SiC: H having a film thickness of 15 nm that is vapor-grown using a mixed gas of SiH ₄ gas / H ₂ gas / CH ₄ gas / B ₂ H ₆ gas. p layer 20, i-layer 21 of S-Si: H having a film thickness of 100 nm grown by vapor phase growth using a mixed gas of SiH ₄ gas and H ₂ gas, S
This is an n-layer 22 of a-Si: H having a film thickness of 15 nm, which is vapor-phase grown using a mixed gas of iH ₄ gas, H ₂ gas, and PH ₃ gas. After forming the photoelectric conversion layers 20, 21, and 22,
An electrode metal layer 23 as a reflection layer having a light reflection effect made of Al and having a film thickness of 100 nm was formed by sputtering.

As shown in FIG. 12, the light collecting and reflecting element 200 and the thin-film solar cell element 300 are mechanically fixed by a fixing metal fitting 29 via a resin spacer 28 having elasticity, and the fixing metal piece 29 of Example 6 is used. A thin film solar cell was completed.

For comparison, the thin-film solar cell comprises only the thin-film solar cell element 300 (referring to FIG. 3), the thickness of the SnO ₂ transparent conductive layer 18 is 100 nm, and the thickness of the i-layer is As a comparative example 2, a thin film solar cell having a conventional structure with a thickness of 300 nm was prepared at the same time. Where S
The reason that the thickness of the nO ₂ transparent conductive layer 18 is 100 nm is that the photoelectric conversion efficiency in the conventional thin film solar cell is maximized due to the antireflection effect of the transparent conductive layer 18.

For the thin film solar cell of Example 6 and the thin film solar cell of Comparative Example 2, an AM1.5 simulator was used for 1
When the IV characteristics were measured by irradiating with light of 00 mW / cm ² , the thin film solar cell of Example 6 had an open circuit voltage of about 5% larger than the thin film solar cell of Comparative Example 2 and a short circuit current. It was confirmed that it was about 55% larger. Therefore, it was found that the thin film solar cell of Example 6 had a photoelectric conversion efficiency of about 63% higher than that of the thin film solar cell of Comparative Example 2.

In Example 6, the amorphous Si thin film semiconductor layers 20, 21 and 22 were used as the photoelectric conversion layers.
It is also possible to use a pn junction made of a polycrystalline Si semiconductor as the photoelectric conversion layer. Further, although a thin-film solar cell in which only one set of photoelectric conversion layers including the amorphous Si thin-film semiconductor layers 20, 21, 22 is formed is described, in the sixth embodiment, the light utilization efficiency due to multiple reflection is described. Is improved, and the amorphous Si thin film semiconductor layers 20, 21, 22 can be thinned. Therefore, these amorphous Si
By stacking a plurality of photoelectric conversion layers composed of the thin film semiconductor layers 20, 21, 22 to form a tandem structure,
It is possible to further improve the open circuit voltage by stacking a plurality of sets of a pn junction made of an amorphous Si semiconductor layer and a pn junction made of a polycrystalline Si semiconductor layer to form a tandem structure.

[0096]

Seventh Embodiment As shown in FIG. 13, the condensing reflective element 200 used in the sixth embodiment and Y ₂ O having a particle diameter of 5 μm are used.
₂ S: 20% by volume of phosphorescent fluorescent particles of Eu, Mg, Ti
The fluorescent glass substrate 30 having a plate thickness of 1 mm and the thin-film solar cell element 300 containing the resin spacer 2 having elasticity
The thin film solar cell of Example 7 was completed by mechanically fixing it with fixing metal fittings 29 through 8.

In the seventh embodiment, as in the case of the second embodiment, the fluorescent glass substrate 30 is provided between the condensing reflection element 200 and the thin-film solar cell element 300, so that the fluorescence in the fluorescent glass substrate 30 is reduced. The light scattered by the luminescent particles and the light emitted from the fluorescent particles are collected and reflected by the condensing reflection element 20.
Most of the incident light and the light emitted from the fluorescent particles are multiple-reflected between the first reflective surface group 11 of 0 and the thin film solar cell element 300, and enter the thin film solar cell element 300, The photoelectric conversion efficiency of the thin film solar cell can be increased.

For the thin-film solar cell of Example 7 and the thin-film solar cell of Comparative Example 2, 1 with an AM1.5 simulator.
When the IV characteristic was measured by irradiating with light of 00 mW / cm ² , the thin-film solar cell of Example 7 had an open circuit voltage of about 10% larger than that of the thin-film solar cell of Comparative Example 2 and a short-circuit current. It was confirmed that it was about 70% larger. Therefore, it was found that the thin film solar cell of Example 7 had a photoelectric conversion efficiency of about 87% higher than that of the thin film solar cell of Comparative Example 2.

In Example 7, the amorphous Si thin film semiconductor layers 20, 21 and 22 were used as the photoelectric conversion layers.
It is also possible to use a pn junction made of a polycrystalline Si semiconductor as the photoelectric conversion layer. Further, although a thin film solar cell in which only one set of photoelectric conversion layers composed of the amorphous Si thin film semiconductor layers 20, 21, 22 is formed is described, in the present Example 7, the light utilization efficiency by multiple reflection is described. Is improved, and the amorphous Si thin film semiconductor layers 20, 21, 22 can be thinned. Therefore, these amorphous Si
By stacking a plurality of photoelectric conversion layers composed of the thin film semiconductor layers 20, 21, 22 to form a tandem structure,
It is possible to further improve the open circuit voltage by stacking a plurality of sets of a pn junction made of an amorphous Si semiconductor layer and a pn junction made of a polycrystalline Si semiconductor layer to form a tandem structure.

In Example 7, the phosphorescent particles of Y ₂ O ₂ S: Eu, Mg, Ti having a particle diameter of 5 μm were used as the fluorescent particles, but the present invention is not limited to this.
For example, as the fluorescent particles, Y ₂ O ₂ having a particle size of 2 to 20 μm is used.
By using the phosphorescent fluorescent particles of S: Eu, Mg, and Ti, light having a wavelength of 200 to 450 nm is absorbed, and 62
It is possible to emit light with a wavelength of 5 nm. Further, by using oxyfluoride-based crystallized glass containing Er ³⁺ ions, it is possible to absorb light having a wavelength of around 800 nm and emit light having a wavelength of 550 to 660 nm.

As fluorescent materials other than these, a rare earth element europium (Eu) and dysprosium (D) are added to a compound consisting of strontium oxide and aluminum oxide.
y) added SrAl ₂ O ₄ : Eu, Dy and Sr ₄
Al ₁₄ O ₂₅ : Eu, Dy and CaAl ₂ O ₄ : E
It is possible to use fluorescent materials such as u, Dy and ZnS: Cu.

[0102]

[Embodiment 8] FIG. 14 shows a cross-sectional view of a thin-film solar cell of Embodiment 8.

In the eighth embodiment, the thin film solar cell element 300 used in the sixth embodiment shown in FIG. 12 and the condensing reflection element 200 are laminated with an acrylic transparent adhesive 31. Here, the thickness of the acrylic transparent adhesive 31 was set to 0.1 mm. With such a structure, the environment resistance can be improved.

The thin film solar cells of Examples 6 and 8 were subjected to an environmental test at 80 ° C. and 80% relative humidity for 2 months. In the thin film solar cells of Example 6, the resin spacer 28 was used. From this part, high-humidity air enters between the condensing reflection element 200 and the thin film solar cell element 300, and the transparent glass substrate 9 of the condensing reflection element 200 and the glass substrate 17 of the thin film solar cell element 300. The surface deterioration of the above occurred, and the power generation efficiency decreased by 3%. On the other hand, it was confirmed that the thin-film solar cell of Example 8 laminated with the acrylic transparent adhesive 31 was excellent in environmental resistance without any change in appearance or reduction in power generation efficiency.

[0105]

[Embodiment 9] FIG. 15 shows a cross-sectional view of a thin-film solar cell of Embodiment 9.

In Example 9, the thin film solar cell element 300 used in Example 7 shown in FIG.
The fluorescent glass substrate 30 of mm and the condensing reflection element 200 are laminated with an acrylic transparent adhesive 31. Here, the thickness of the acrylic transparent adhesive 31 was set to 0.1 mm. With such a structure, the environment resistance can be improved.

The thin film solar cells of Examples 7 and 9 were subjected to an environmental test at 80 ° C. and a relative humidity of 80% for 2 months. In the thin film solar cells of Example 7, a resin spacer 28 was used. From this part, high-humidity atmosphere enters between the condensing reflection element 200, the fluorescent glass substrate 30 and the thin film solar cell element 300, and the transparent glass substrate 9 of the condensing reflection element 200 and the thin film solar cell element. The surface deterioration of the glass substrate 17 of 300 and the fluorescent glass substrate 30 occurs,
Power generation efficiency dropped by 4%. On the other hand, it was confirmed that the thin-film solar cell of Example 9 laminated with the acrylic transparent adhesive 31 had excellent environmental resistance without any change in appearance or reduction in power generation efficiency.

[0108]

[Embodiment 10] FIG. 16 shows a cross-sectional view of a thin film solar cell of Embodiment 10.

In the tenth embodiment, the thin-film solar cell element 300 used in the sixth embodiment shown in FIG. 12 and the condensing reflecting element 200 are prepared by using Y ₂ O ₂ S: Eu
It has a structure in which a fluorescent acrylic transparent adhesive 32 containing 20% by volume of Mg and Ti phosphorescent fluorescent particles is stuck. Here, the fluorescent acrylic transparent adhesive 32
Has a thickness of 0.5 mm. Also in the configuration of Example 10, the fluorescent acrylic transparent adhesive 3 containing the fluorescent particles is used.
2 is a wavelength 400 not used for photoelectric conversion, like the fluorescent glass substrate 30 shown in Examples 7 and 9.
wavelength of 600nm, which is used for photoelectric conversion
It is converted into the nearby light and the power generation efficiency is improved.

Thin film solar cell of Example 10 and Comparative Example 2
The thin film solar cell of Example 10 was irradiated with light of 100 mW / cm ² with an AM1.5 simulator, and the IV characteristics were measured. The thin film solar cell of Example 10 was compared with the thin film solar cell of Comparative Example 2. It was confirmed that the open circuit voltage was about 2% higher and the short circuit current was about 60% higher.
Therefore, it was found that the thin film solar cell of Example 10 had a photoelectric conversion efficiency of about 63% higher than that of the thin film solar cell of Comparative Example 2.

In Example 10, the amorphous Si thin film semiconductor layers 20, 21 and 22 (see FIG. 3) were used as the photoelectric conversion layer, but a pn junction made of a polycrystalline Si semiconductor was used as the photoelectric conversion layer. It is also possible. Further, although a thin film solar cell in which only one set of photoelectric conversion layers including the amorphous Si thin film semiconductor layers 20, 21, 22 is formed is described, in the tenth embodiment, light utilization efficiency due to multiple reflection is described. Of the amorphous Si thin film semiconductor layer 2
It is possible to make 0, 21, 22 thin. Therefore,
By stacking a plurality of photoelectric conversion layers composed of these amorphous Si thin film semiconductor layers 20, 21, 22 to form a tandem structure, a pin junction by an amorphous Si semiconductor layer and a pn by a polycrystalline Si semiconductor layer are formed. The open circuit voltage can be further improved by stacking a plurality of sets of junctions and forming a tandem structure.

[0112]

[Embodiment 11] FIG. 17 shows a cross-sectional view of a thin-film solar cell of Embodiment 11.

In the eleventh embodiment, the thin film solar cell element 400 includes a fluorescent glass substrate 33 in place of the glass substrate 17 (see FIG. 3) of the thin film solar cell element 300 described in the sixth embodiment shown in FIG. I am using. In other respects, the thin film solar cell element 400 of Example 11 and the thin film solar cell element 300 of Example 6 have the same configuration. Also,
The condensing reflective element 200 of the eleventh embodiment has the same configuration as the condensing reflective element 200 of the first embodiment, and therefore the same reference numerals are given and the description thereof is omitted.

The fluorescent glass substrate 33 comprises 20 phosphorescent particles of Y ₂ O ₂ S: Eu, Mg, Ti having a particle size of 5 μm.
It is a fluorescent glass substrate having a plate thickness of 2 mm and containing volume%.

As shown in FIG. 17, the thin film solar cell element 400 and the light converging / reflecting element 200, which have the fluorescent glass substrate 33 as a substrate, are fixed by a fixing bracket 29 via a resin spacer 28 having elasticity. By mechanically fixing, the thin film solar cell of Example 11 was completed.

The thin film solar cell of Example 11 and Comparative Example 2
The thin film solar cell of Example 11 was irradiated with light of 100 mW / cm ² with an AM1.5 simulator, and the IV characteristics were measured. The thin film solar cell of Example 11 was compared with the thin film solar cell of Comparative Example 2. It was confirmed that the open circuit voltage was about 10% higher and the short circuit current was about 60% higher. Therefore, it was found that the thin film solar cell of Example 11 had a photoelectric conversion efficiency of about 76% higher than that of the thin film solar cell of Comparative Example 2.

In Example 11, the amorphous Si thin film semiconductor layers 20, 21 and 22 (see FIG. 3) were used as the photoelectric conversion layer, but a pn junction made of a polycrystalline Si semiconductor was used as the photoelectric conversion layer. It is also possible. Further, although a thin film solar cell in which only one set of photoelectric conversion layers including the amorphous Si thin film semiconductor layers 20, 21, 22 is formed is described, in the eleventh embodiment, the light utilization efficiency due to multiple reflection is used. Of the amorphous Si thin film semiconductor layer 2
It is possible to make 0, 21, 22 thin. Therefore,
By stacking a plurality of photoelectric conversion layers composed of these amorphous Si thin film semiconductor layers 20, 21, 22 to form a tandem structure, a pin junction by an amorphous Si semiconductor layer and a pn by a polycrystalline Si semiconductor layer are formed. The open circuit voltage can be further improved by stacking a plurality of sets of junctions and forming a tandem structure.

In the eleventh embodiment, Y ₂ O ₂ S: Eu, Mg, Ti phosphorescent fluorescent particles having a particle size of 5 μm are used as the fluorescent particles, but the present invention is not limited to this. For example, as the fluorescent particles, Y _{2 having} a particle size of 2 to 20 μm is used.
By using the phosphorescent fluorescent particles of O ₂ S: Eu, Mg, and Ti, light having a wavelength of 200 to 450 nm is absorbed,
It is possible to emit light with a wavelength of 625 nm.
Further, by using oxyfluoride-based crystallized glass containing Er ³⁺ ions, it is possible to absorb light having a wavelength of around 800 nm and emit light having a wavelength of 550 to 660 nm.

As fluorescent materials other than these, compounds containing strontium oxide and aluminum oxide are added to the rare earth elements europium (Eu) and dysprosium (D).
y) added SrAl ₂ O ₄ : Eu, Dy and Sr ₄
Al ₁₄ O ₂₅ : Eu, Dy and CaAl ₂ O ₄ : E
It is possible to use fluorescent materials such as u, Dy and ZnS: Cu.

[0120]

[Embodiment 12] FIG. 18 shows a cross-sectional view of a thin film solar cell of Embodiment 12.

In the twelfth embodiment, the condensing reflection element 200 described in the eleventh embodiment shown in FIG. 17 and the thin-film solar cell element 400 using the fluorescent glass substrate 33 are laminated with an acrylic transparent adhesive 31. Has become. Here, the thickness of the acrylic transparent adhesive 31 was set to 0.1 mm. With such a structure, the environment resistance can be improved.

The thin film solar cells of Examples 11 and 12 were subjected to an environmental test at 80 ° C. and 80% relative humidity for 2 months. In the thin film solar cells of Example 11, the resin spacer 28 was used. From this part, the high-humidity atmosphere enters between the light collecting and reflecting element 200 and the thin film solar cell element 400, and the transparent glass substrate 9 of the light collecting and reflecting element 200,
In addition, the surface of the fluorescent glass substrate 33 of the thin-film solar cell element 300 was altered and the power generation efficiency was reduced by 4%. On the other hand, it was confirmed that the thin-film solar cell of Example 12 laminated with the acrylic transparent adhesive 31 did not cause a change in appearance or a decrease in power generation efficiency and was excellent in environmental resistance.

Instead of the acrylic transparent adhesive 31 described above, it is also possible to use a transparent adhesive having fluorescent characteristics.

[0124]

[Embodiment 13] FIG. 19 shows a cross-sectional view of a thin film solar cell of Embodiment 13.

In the thirteenth embodiment, the condenser reflection element 5
00 is the condenser reflection element 2 described in the first embodiment shown in FIG.
In place of the transparent glass substrate 9 of No. 00, a transparent glass substrate 34 having a fluorescent property is used. In other respects, the condensing and reflecting element 500 of Example 13 and the condensing and reflecting element 200 of Example 1 have the same configuration. Also,
The thin-film solar cell element 100 of Example 13 has the same configuration as the thin-film solar cell element 100 of Example 1, and therefore, the same reference numerals are given and the description thereof is omitted.

The transparent glass substrate 34 having the above-mentioned fluorescent property.
As Y ₂ O ₂ S: Eu, Mg, Ti having a particle diameter of 5 μm
The fluorescent glass substrate 34 having a plate thickness of 2 mm and containing 20% by volume of the phosphorescent fluorescent particles was used.

The condensing reflection element 500 and the thin-film solar cell element 100 using the fluorescent glass substrate 34 as a substrate are shown in FIG.
As shown in FIG. 13, mechanical fixing is performed by fixing metal fittings 29 via a resin spacer 28 having elasticity, and
Completed the thin film solar cell.

The thin film solar cell of Example 13 and Comparative Example 2
The thin film solar cell of Example 13 was irradiated with light of 100 mW / cm ² with an AM1.5 simulator, and the IV characteristics were measured. The thin film solar cell of Example 13 was compared with the thin film solar cell of Comparative Example 2. It was confirmed that the open circuit voltage was about 2% higher and the short circuit current was about 70% higher.
Therefore, it was found that the thin film solar cell of Example 13 had a photoelectric conversion efficiency of about 73% higher than that of the thin film solar cell of Comparative Example 2.

In Example 13, the polycrystalline Si thin film semiconductor layers 3, 4, and 5 (see FIG. 1) were used as the photoelectric conversion layer, but a pin junction made of an amorphous Si semiconductor was used as the photoelectric conversion layer. It is also possible. In addition, polycrystalline Si
Although a thin film solar cell in which only one set of photoelectric conversion layers including the thin film semiconductor layers 3, 4, and 5 is formed is described, in Example 13, the light utilization efficiency is improved by multiple reflection, It is possible to thin the polycrystalline Si thin film semiconductor layers 3, 4, 5. Therefore, these polycrystalline Si
By stacking a plurality of photoelectric conversion layers composed of the thin film semiconductor layers 3, 4, and 5 to form a tandem structure, a plurality of pairs of a pin junction made of an amorphous Si semiconductor layer and a pn junction made of a polycrystalline Si semiconductor layer are stacked. By adopting a tandem structure as a result, the open circuit voltage can be further improved.

Further, in the thirteenth embodiment, the phosphorescent particles of Y ₂ O ₂ S: Eu, Mg, Ti having a particle diameter of 5 μm are used as the fluorescent particles, but the present invention is not limited to this. For example, as the fluorescent particles, Y _{2 having} a particle size of 2 to 20 μm is used.
By using the phosphorescent fluorescent particles of O ₂ S: Eu, Mg, and Ti, light having a wavelength of 200 to 450 nm is absorbed,
It is possible to emit light with a wavelength of 625 nm.
Further, by using oxyfluoride-based crystallized glass containing Er ³⁺ ions, it is possible to absorb light having a wavelength of around 800 nm and emit light having a wavelength of 550 to 660 nm.

As fluorescent materials other than these, a rare earth element europium (Eu) and dysprosium (D) are added to a compound consisting of strontium oxide and aluminum oxide.
y) added SrAl ₂ O ₄ : Eu, Dy and Sr ₄
Al ₁₄ O ₂₅ : Eu, Dy and CaAl ₂ O ₄ : E
It is possible to use fluorescent materials such as u, Dy and ZnS: Cu.

[0132]

[Embodiment 14] FIG. 20 shows a cross-sectional view of a thin film solar cell of Embodiment 14.

In the fourteenth embodiment, the thin film solar cell element 100 of the thirteenth embodiment and the condensing reflection element 500 using the transparent glass substrate 34 having the fluorescent property are bonded together by the acrylic transparent adhesive 31. Has become. Here, the thickness of the acrylic transparent adhesive 31 is set to 0.1.
mm. With such a structure, the environment resistance can be improved.

The thin film solar cells of Examples 13 and 14 were subjected to an environmental test at 80 ° C. and 80% relative humidity for 2 months. In the thin film solar cells of Example 13, the resin spacer 28 was used. From this part, high-humidity atmosphere entered between the condensing reflection element 200 and the thin film solar cell element 300, corrosion of the thin film solar cell element started, and the power generation efficiency decreased by 23%. On the other hand, it was confirmed that the thin-film solar cell of Example 14 bonded with the acrylic transparent adhesive 31 had excellent environmental resistance without any change in appearance or reduction in power generation efficiency.

Instead of the acrylic transparent adhesive 31 described above, it is also possible to use a transparent adhesive having fluorescent characteristics.

[0136]

Fifteenth Embodiment FIG. 21 shows a cross-sectional view of the thin film solar cell of the fifteenth embodiment.

The thin film solar cell of Example 15 is the same as the thin film solar cell element 100 of the thin film solar cell of Example 13 shown in FIG. 19 except that the thin film solar cell element 300 of Example 6 shown in FIG. 12 is used. Only the points used were from Example 13.
Different from the thin film solar cell.

In the thin-film solar cell of Example 15, the condensing reflection element 5 using the transparent glass substrate 34 having the fluorescent property.
00 and the thin-film solar cell element 300 are mechanically fixed by a fixing metal fitting 29 via a resin spacer 28 having elasticity.

The thin film solar cell of Example 15 and Comparative Example 2
The thin film solar cell of Example 15 was irradiated with light of 100 mW / cm ² with an AM1.5 simulator, and the IV characteristics were measured. The thin film solar cell of Example 15 was compared with the thin film solar cell of Comparative Example 2. It was confirmed that the open circuit voltage was about 10% higher and the short circuit current was about 65% higher. Therefore, it was found that the thin film solar cell of Example 15 had a photoelectric conversion efficiency of about 82% higher than that of the thin film solar cell of Comparative Example 2.

[0140]

[Embodiment 16] FIG. 22 shows a cross-sectional view of a thin-film solar cell of Embodiment 16.

In the sixteenth embodiment, the thin-film solar cell element 300 of the fifteenth embodiment and the light condensing / reflecting element 500 using the transparent glass substrate 34 having a fluorescent characteristic are bonded together by an acrylic transparent adhesive 31. Has become. Here, the acrylic transparent adhesive 31 has a thickness of 0.
It was set to 1 mm. With such a structure, the environment resistance can be improved.

The thin film solar cells of Examples 15 and 16 were subjected to an environmental test at 80 ° C. and a relative humidity of 80% for 2 months. In the thin film solar cells of Example 15, the resin spacer 28 was used. From this part, the high-humidity atmosphere enters between the condensing reflection element 500 and the thin film solar cell element 300, and the transparent glass substrate 34 having the fluorescence characteristic of the condensing reflection element 500 and the thin film solar cell element 300. The surface deterioration of the transparent glass substrate 17 (see FIG. 3) occurred, and the power generation efficiency decreased by 3%. On the other hand, it was confirmed that the thin-film solar cell of Example 16 bonded with the acrylic transparent adhesive 31 had excellent environmental resistance without causing a change in appearance or a decrease in power generation efficiency.

Instead of the acrylic transparent adhesive 31 described above, it is also possible to use a transparent adhesive having fluorescent characteristics.

[0144]

As is apparent from the above, according to the thin-film solar cell of the present invention, the incident light is condensed in the light transmitting hole group by the second reflecting surface group of the light collecting and reflecting element, and The light from the light transmitting hole passes through the transparent substrate, enters the thin film solar cell element, and is multiply reflected between the thin film solar cell element and the first reflecting surface group of the condensing reflective element. Therefore, according to the present invention, the incident light is condensed by the second reflecting surface group, is passed through the light transmitting hole, and the light passing through the light transmitting hole is effectively escaped without being escaped by the first reflecting surface group. Due to the synergistic effect of the use point and the point that light is multiple-reflected between the first reflective surface group of the condensing reflection element and the thin-film solar cell element and is applied to the photoelectric conversion layer, It is possible to remarkably increase the light quantity of the light to be radiated, and to make the power generation efficiency extremely high.

According to one embodiment, the second reflecting surface group of the light converging / reflecting element is a flat surface-shaped inclined surface group inclined with respect to one surface of the transparent substrate, and thus is a curved surface group. Compared with the case, the structure is simple, and since the second reflecting surface group is located on both sides of the light transmitting hole group, it is possible to effectively collect light.

Further, in one embodiment, the first reflecting surface group of the light collecting and reflecting element is a reflecting film provided on the bottom surfaces of a plurality of triangular prisms, and the second film of the second light collecting and reflecting element is formed. The reflective surface group is a reflective film provided on the side surfaces of the plurality of triangular prisms, and the bottom surface of the triangular prism is fixed to the one surface of the transparent substrate via the first reflective surface. .

Therefore, according to the above embodiment, the light is condensed by a simple method such that the bottom surface of the triangular prism having the reflection film formed on the bottom surface and the side surface is fixed on the transparent substrate. Second group of reflective surfaces, and the first for multiple reflection
It is possible to form a condensing reflective element having a group of reflective surfaces. Therefore, cost reduction of a highly efficient thin film solar cell can be realized.

Further, according to one embodiment, since the base angle of the triangle, which is the cross section of the triangular prism, is 67.5 degrees or more, the light is reflected by the second reflecting surface provided on the side surface of the triangular prism. It is possible to collect incident light on the transmission hole.

Further, according to one embodiment, since the apex angle of the isosceles triangle, which is the cross section of the triangular prism, is smaller than 45 degrees, the second reflecting surface is effective even if the sun is not directly above. Can be focused. Therefore, the amount of light with which the photoelectric conversion layer of the thin film solar cell is irradiated is increased, and power generation efficiency can be increased.

Further, according to one embodiment, since the apex angle of the isosceles triangle is smaller than 30 degrees, the second reflecting surface collects light more effectively even if the sun is not directly above. be able to. Therefore, the amount of light with which the photoelectric conversion layer of the thin film solar cell is irradiated is further increased, and the power generation efficiency can be further increased.

Further, in one embodiment, since the transparent substrate having the fluorescent property is installed between the light collecting and reflecting element and the thin film solar cell element, the second light collecting and reflecting element of the second embodiment is provided.
The light that is collected by the reflective surface group of and passes through the light transmission hole is
The light having a wavelength range that cannot be used for photoelectric conversion is converted into light having a wavelength range that can be used for photoelectric conversion by being incident on a transparent substrate having a fluorescence property, and is randomly radiated and scattered. Then, multiple reflection is performed between the first reflective surface group of the condensing reflective element and the thin film solar cell element. Therefore, the light that has been condensed by the second reflecting surface group of the light collecting and reflecting element and has once passed through the light transmitting hole is
A point of effectively using the reflective surface group so as not to escape, and a point of converting a light in a wavelength range that cannot be used for photoelectric conversion into a light of a wavelength range that can be used for photoelectric conversion by a transparent substrate having a fluorescent property, Light is multiply reflected between the thin-film solar cell element and the first reflecting surface and is applied to the photoelectric conversion layer, and light in a wavelength range that cannot be used for photoelectric conversion due to a transparent substrate having multiple reflection and fluorescence characteristics. By the synergistic effect with the point that the light in the wavelength range that can be used for photoelectric conversion is irradiated to the photoelectric conversion layer, the amount of light in the wavelength range that contributes to the photoelectric conversion irradiated to the photoelectric conversion layer is significantly increased. The power generation efficiency can be extremely high.

Further, in one embodiment, since the substrate of the thin film solar cell element is a transparent substrate functioning as a fluorescent layer, the light incident from the light transmitting hole group and the transparent substrate having the fluorescent characteristic are used for photoelectric conversion. The light in the wavelength range that can be used for photoelectric conversion is converted from the light in the wavelength range that cannot be used for
Multiple reflection occurs between the thin-film solar cell element and the first reflecting surface group of the condensing reflecting element. Therefore, the amount of light in the wavelength range that contributes to photoelectric conversion applied to the photoelectric conversion layer is increased, and power generation efficiency can be increased.

Further, in one embodiment, since the transparent substrate of the light converging / reflecting element is a transparent substrate having a fluorescent characteristic and the transparent substrate functions as a fluorescent layer, the light incident from the light transmitting hole group is And light converted into light in a wavelength range that cannot be used for photoelectric conversion by the transparent substrate having the above-mentioned fluorescence characteristics into light in a wavelength range that can be used for photoelectric conversion. Multiple reflection is performed with the reflection surface group. Therefore, the amount of light in the wavelength range that contributes to photoelectric conversion applied to the photoelectric conversion layer is increased, and power generation efficiency can be increased.

Further, according to one embodiment, since the light collecting and reflecting element is mechanically fixed to the thin film solar cell element through the spacer, the light collecting and reflecting element is attached to the thin film solar cell element. Easy to install. Also,
The thin-film solar cell of the above-described embodiment can be configured by simply attaching the condensing reflection element to the conventional thin-film solar cell, and easily improving the power generation efficiency of the conventional thin-film solar cell. Is possible. Further, the thin-film solar cell element and the light-collecting and reflecting element can be easily separated and replaced with each other. Further, the thin film solar cell element can be protected by the light converging and reflecting element to improve the reliability of the thin film solar cell.

Further, in one embodiment, the thin-film solar cell element, the transparent substrate having the fluorescent property, and the light-collecting / reflecting element are mechanically fixed through a spacer, so that It is possible to fix them to, and they can be easily disassembled and replaced. Further, with respect to the conventional thin-film solar cell, the transparent substrate having the fluorescent property and the condensing reflection element can be easily attached to easily configure the thin-film solar cell of the above-described embodiment, It is possible to easily improve the power generation efficiency of the thin film solar cell. Further, the thin film solar cell element and the transparent substrate having the fluorescent property can be protected by the light converging and reflecting element to improve the reliability of the thin film solar cell.

Further, in one embodiment, the thin film solar cell element, the transparent substrate having the fluorescent property, and the light converging / reflecting element are fixed by an adhesive, so that they can be fixed easily and firmly. It is possible to obtain a highly reliable thin film solar cell having excellent environment resistance. Further, when the adhesive is a transparent adhesive, the appearance does not deteriorate even if the adhesive is squeezed out.

Further, in one embodiment, since the thin film solar cell element and the light converging / reflecting element are fixed by an adhesive, they can be fixed easily and firmly, and the environment resistance is excellent. It is possible to obtain a thin film solar cell having high properties.

In one embodiment, since a transparent adhesive having a fluorescent property is used, this transparent adhesive has a function of connecting the condensing reflection element and the thin film solar element, and
It has a function as a fluorescent layer that converts light in a wavelength range that cannot be used for photoelectric conversion into light in a wavelength range that can be used for photoelectric conversion to improve photoelectric conversion efficiency. Therefore, the photoelectric conversion efficiency can be increased with a simple structure.

Further, in one embodiment, since the photoelectric conversion layer is located between the reflecting layer of the thin film solar cell element and the incident surface, the first layer of the reflecting layer of the thin film solar cell element and the condensing reflecting element is formed. Sandwiching the photoelectric conversion layer and the fluorescent layer between the reflective surface of
Light is multiply reflected between the reflective layer of the solar cell element and the first reflective surface of the condensing reflective element. Therefore, it is possible to remarkably increase the light amount of the light in the wavelength region that contributes to the photoelectric conversion applied to the photoelectric conversion layer, and to make the power generation efficiency extremely high.

[Brief description of drawings]

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

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

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

FIG. 4 is a diagram showing a method for manufacturing the condensing reflective element of the thin-film solar cell in Example 1 of the present invention.

FIG. 5 is a diagram showing a method for manufacturing the condensing reflective element of the thin-film solar cell in Example 1 of the present invention.

FIG. 6 is a diagram showing a method for manufacturing the condensing reflective element of the thin-film solar cell in Example 1 of the present invention.

FIG. 7 is a cross-sectional view of a thin-film solar cell of Example 1 of the present invention.

FIG. 8 is a cross-sectional view of a thin film solar cell according to a second embodiment of the present invention.

FIG. 9 is a cross-sectional view of a thin film solar cell of Example 3 of the present invention.

FIG. 10 is a cross-sectional view of a thin film solar cell of Example 4 of the present invention.

FIG. 11 is a cross-sectional view of a thin film solar cell of Example 5 of the present invention.

FIG. 12 is a cross-sectional view of a thin-film solar cell of Example 6 of the present invention.

FIG. 13 is a cross-sectional view of a thin-film solar cell of Example 7 of the present invention.

FIG. 14 is a cross-sectional view of a thin-film solar cell of Example 8 of the present invention.

FIG. 15 is a cross-sectional view of a thin-film solar cell of Example 9 of the present invention.

FIG. 16 is a cross-sectional view of a thin film solar cell of Example 10 of the present invention.

FIG. 17 is a cross-sectional view of a thin film solar cell of Example 11 of the present invention.

FIG. 18 is a cross-sectional view of a thin film solar cell of Example 12 of the present invention.

FIG. 19 is a cross-sectional view of a thin film solar cell of Example 13 of the present invention.

FIG. 20 is a cross-sectional view of a thin film solar cell of Example 14 of the present invention.

FIG. 21 is a cross-sectional view of a thin film solar cell of Example 15 of the present invention.

FIG. 22 is a sectional view of a thin-film solar cell of Example 16 of the present invention.

FIG. 23 is a cross-sectional view of a conventional thin film solar cell.

FIG. 24 is a cross-sectional view of a conventional thin film solar cell.

FIG. 25 is a cross-sectional view of a conventional thin film solar cell.

[Explanation of symbols]

1,17 Substrate that doubles as a support 2,23 electrode metal layer 3,4,5 Polycrystalline Si semiconductor layer 6,19 Current collecting electrode 9 Transparent substrate 10 Light transmission hole group 11 First reflective surface group 13 Second reflective surface group 15 3 prism 16 vertical angle 17 glass substrate 20 Amorphous Si semiconductor p layer 21 Amorphous Si semiconductor i layer 22 Amorphous Si semiconductor n layer 2,23 electrode metal layer 28 Resin spacer 29 Fixing bracket 30 Fluorescent glass substrate 31 Acrylic transparent adhesive 32 Fluorescent acrylic transparent adhesive 33,34 Fluorescent glass substrate 100,300,400 Thin film solar cell element 200,500 Reflective condensing element

Claims (15)

[Claims] 1. A thin-film solar cell element having a photoelectric conversion layer, a transparent substrate, a first reflecting surface group provided on one surface of the transparent substrate and having a light transmitting hole group, and the light transmitting hole. A second reflecting surface group that collects incident light; and a light collecting surface of the thin film solar cell element, and the other surface of the transparent substrate of the light collecting and reflecting element faces the light entrance surface. The thin film solar cell is characterized in that a condensing reflection element is attached to the thin film solar cell element. 2. The thin-film solar cell according to claim 1, wherein the second reflective surface group of the condensing reflective element is a planar inclined surface group inclined with respect to the one surface of the transparent substrate. In addition, the thin film solar cell is located on both sides of the light transmitting hole. 3. The thin-film solar cell according to claim 2, wherein the first reflective surface group of the condensing reflective element is a reflective film provided on the bottom surfaces of a plurality of triangular prisms, and the condensing reflective element is provided. The second reflective surface group of the element is a reflective film provided on the side surfaces of the plurality of triangular prisms, and the bottom surface of the triangular prisms is provided on the one surface of the transparent substrate via the first reflective surface. A thin film solar cell characterized by being fixed to. 4. The thin film solar cell according to claim 3, wherein the base angle of the triangle, which is the cross section of the triangular prism, is 67.5 degrees or more. 5. The thin-film solar cell according to claim 3 or 4, wherein the triangle that is the cross section of the triangular prism is an isosceles triangle, and the apex angle of the isosceles triangle is smaller than 45 degrees. A thin film solar cell characterized by. 6. The thin film solar cell according to claim 5, wherein the isosceles triangle has an apex angle smaller than 30 degrees. 7. The thin film solar cell according to claim 1, wherein a transparent substrate having a fluorescent property is provided between the condensing reflection element and the thin film solar cell element. A thin film solar cell characterized by the above. 8. The thin film solar cell according to claim 1, wherein the substrate of the thin film solar cell element is a transparent substrate having a fluorescent property. 9. The thin film solar cell according to claim 1, wherein the transparent substrate of the condensing reflective element has a fluorescent characteristic. 10. The thin-film solar cell according to claim 1, wherein the thin-film solar cell element and the condensing reflection element are mechanically fixed via a spacer. The thin film solar cell is characterized in that 11. The thin-film solar cell according to claim 7, wherein the thin-film solar cell element, the transparent substrate having the fluorescent property, and the condensing reflection element are mechanically fixed via a spacer. A thin film solar cell characterized by. 12. The thin-film solar cell according to claim 7, wherein the thin-film solar cell element, the transparent substrate having the fluorescent characteristic, and the condensing reflection element are fixed by an adhesive. Thin film solar cell. 13. The thin-film solar cell according to claim 1, wherein the thin-film solar cell element and the condensing reflective element are fixed by an adhesive. Characteristic thin film solar cell. 14. The thin-film solar cell according to claim 13, wherein the adhesive is a transparent adhesive having a fluorescent property. 15. The thin-film solar cell according to claim 1, wherein the thin-film solar cell element includes a reflective layer located on the side opposite to the light incident surface with respect to the photoelectric conversion layer. A thin film solar cell characterized by the above.