JP2011171512A - Sealant for solar cell, and solar cell using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealant for a solar cell capable of improving photoelectric conversion efficiency, and to provide a solar cell excelling in photoelectric conversion efficiency and excelling in a practical characteristic. <P>SOLUTION: In this sealant for a solar cell prepared by dispersing or dissolving a fluorescent substance in a transparent resin, the fluorescent substance absorbs light in a wavelength region of 350-400 nm more than light in a wavelength over 400 nm, and has an average particle size ≤20 nm. The optical transmittance of the sealant for a solar cell at a wavelength of 600-800 nm is ≥90%. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a solar cell encapsulant used for sealing solar cells and a solar cell using the same, and in particular, a novel solar cell encapsulant having a wavelength conversion effect and the solar cell. It is related with the solar cell which formed the sealing agent layer using the sealing agent for water.

  Solar cells that convert solar energy into electrical energy are attracting attention as clean renewable energy, replacing fossil fuels that emit greenhouse gases such as carbon dioxide. If solar cells are widely spread and can cover a part of electric power, the significance of environmental protection will be great.

  Against this background, solar cells are being developed in various directions. However, in practical use of solar cells, poor energy conversion efficiency is a major problem. That is, when performing photoelectric conversion, the solar battery cell can use only light having a part of the wavelength of sunlight, and this is a factor in reducing conversion efficiency.

  As one of the methods for solving this problem, sunlight in a short wavelength region that cannot be used by solar cells is converted into light in a long wavelength region that can be used by solar cells, and a fluorescent material or the like is used as a wavelength conversion material. Wavelength conversion techniques have been proposed. A solar cell using this wavelength conversion technology has also been proposed.

  For example, Patent Document 1 discloses a wavelength converter that absorbs light in a wavelength range with a low photoelectric conversion efficiency in the photoelectric conversion layer and emits light in a wavelength range with a high photoelectric conversion efficiency on the light incident side of the photoelectric conversion layer. A solar cell in which the layer is arranged in parallel with the photoelectric conversion layer is disclosed. In the solar cell described in Patent Document 1, for example, the wavelength converter layer is formed by dispersing and mixing the wavelength converter fine powder in the transparent adhesive layer between the photoelectric conversion layer and the transparent protective cover. Forming.

  Further, for example, in Patent Document 2, in a solar battery module including a solar battery cell that converts solar energy into electrical energy, the irradiated light is absorbed, and the absorbed light is converted into light having a longer wavelength. A solar cell module having a wavelength conversion layer for conversion is disclosed. In the solar cell module described in Patent Document 2, the wavelength conversion layer is formed by being applied to the light receiving surface or is formed as a sealing material that protects the solar cells.

  For example, Patent Document 3 discloses a solar cell in which a material containing an oxide fluorescent substance is disposed in a path until light reaches the solar cell element. Here, the oxide fluorescent material is capable of converting ultraviolet rays in a wavelength range of 200 to 400 nm into a wavelength range of 400 to 1000 nm.

JP 63-200576 A JP-A-7-202243 JP 2003-218379 A

  However, even if a solar cell is manufactured based on the techniques described in Patent Documents 1 to 3, satisfactory results are not always obtained in terms of, for example, photoelectric conversion efficiency. As one of the causes, it is mentioned that the examination regarding the absorption characteristics, emission characteristics, sunlight transmittance, etc. of the fluorescent material used for wavelength conversion is insufficient.

  For example, in any of the techniques described in Patent Documents 1 to 3, it is specified that light in a short wavelength range with low photoelectric conversion efficiency is absorbed and light in a longer wavelength range is emitted. In particular, there has been little investigation on what kind of absorption spectrum a fluorescent material should have. In particular, when a sealant layer formed on the front surface of a solar cell that performs photoelectric conversion is used as a wavelength conversion layer, efficiency improvement by wavelength conversion is realized to the maximum, and the sealant layer itself is a solar cell. It is necessary to optimize so as not to interfere with sunlight absorption.

  The present invention has been proposed in view of such a conventional situation, and provides a solar cell encapsulant capable of realizing higher photoelectric conversion efficiency than a conventional one and a solar cell using the same. The purpose is to do.

  In order to achieve the above-described object, the sealing agent for solar cells of the present invention is a sealing agent for solar cells in which a fluorescent material is dispersed or dissolved in a transparent resin, and the fluorescent material has a thickness of 350 nm to 400 nm. It absorbs more light in the wavelength range than light in the wavelength range exceeding 400 nm.

  Moreover, the solar cell of the present invention is a solar cell in which a transparent protective glass is bonded to a solar cell having a photoelectric conversion layer via a sealant layer, and the sealant layer is made of a transparent resin. The fluorescent material is formed by a sealing agent for solar cells in which a fluorescent material is dispersed or dissolved, and the fluorescent material contained in the sealing agent layer is obtained by converting light in a wavelength region of 350 nm to 400 nm from light in a wavelength region exceeding 400 nm. It is also characterized by absorbing a large amount.

  The fluorescent material used for the solar cell encapsulant functions as a wavelength converter, and as described in the above Patent Documents 1 to 3 and the like, a short photoelectric conversion efficiency in the photoelectric conversion layer is low. It is necessary to absorb light in the wavelength range and emit light in the long wavelength range with high photoelectric conversion efficiency. However, it is not always necessary that there is absorption in a short wavelength region (for example, a wavelength region of 400 nm or less). For example, even if there is absorption in a wavelength region of 400 nm or less, if there is absorption in a wavelength region longer than 400 nm, light necessary for photoelectric conversion in the photoelectric conversion layer will also be absorbed, and efficiency improvement by wavelength conversion Is offset and sufficient conversion efficiency cannot be realized. The sealing agent for solar cells of this invention contains the fluorescent substance which absorbs 350 nm-400 nm light more than the light of the wavelength range exceeding 400 nm. Accordingly, light that cannot be absorbed by the photoelectric conversion layer can be efficiently photoelectrically converted to be usable, and thus effective conversion efficiency can be improved.

  Further, in the solar cell encapsulant of the present invention, in addition to such a configuration, the average particle diameter of the fluorescent material may be 20 nm or less, and the light transmittance at a wavelength of 600 nm to 800 nm of the encapsulant may be 90% or more. Good. In this case, the encapsulant itself does not hinder the arrival of sunlight to the photoelectric conversion layer, and further improvement in photoelectric conversion efficiency can be realized. When performing wavelength conversion using a fluorescent material, if the particle size of the fluorescent material is 100 nm or more, the conversion efficiency may greatly decrease due to the scattering of sunlight, etc. This is a problem with solar cells that employ a wavelength conversion layer. It was one of the causes that were difficult to put into practical use. The sealing agent for solar cells of this invention eliminates such a problem by making the average particle diameter of a fluorescent substance 20 nm or less, and making the light transmittance in wavelength 600-800 nm of a sealing agent 90% or more. It becomes possible.

  According to the present invention, light in a wavelength range that could not directly contribute to photoelectric conversion can be effectively used for photoelectric conversion, for example, light that can be used in the photoelectric conversion layer of the solar cell can be expanded, It becomes possible to realize a solar cell having a good photoelectric conversion efficiency.

It is a figure which shows the absorption characteristic in the photovoltaic cell which uses a single crystal silicon as a photoelectric converting layer. It is typical sectional drawing which shows schematic structure of a solar cell. (A) is a figure which shows the absorption spectrum of fluorescent substance CdSe nanoparticle, (b) is a figure which shows the emission spectrum. (A) is a figure which shows the absorption spectrum of fluorescent substance DPhP-C4, (b) is a figure which shows the emission spectrum. (A) is a figure which shows the absorption spectrum of fluorescent substance ADS085, (b) is a figure which shows the emission spectrum. It is a figure which shows an example of the sample cell used for evaluation, and is a schematic sectional drawing of the evaluation cell using the photovoltaic cell which uses a polycrystalline silicon as a photoelectric converting layer. It is a figure which shows the absorption characteristic in the photovoltaic cell which uses a polycrystalline silicon as a photoelectric converting layer. It is a figure which shows an example of the sample cell used for evaluation, and is a schematic sectional drawing of the evaluation cell using the photovoltaic cell which uses single crystal silicon as a photoelectric converting layer.

  Hereinafter, an embodiment of a sealing agent for solar cells to which the present invention is applied and a solar cell using the same (hereinafter referred to as “this embodiment”) will be described with reference to the drawings.

  The sealing agent for solar cells of this Embodiment is arrange | positioned in the front surface of the photovoltaic cell which has a photoelectric converting layer, is used for bonding together two transparent protective glasses, and functions also as an adhesive agent. In this transparent resin, a fluorescent substance that is a wavelength converter is dispersed or dissolved.

  The fluorescent substance performs wavelength conversion on transmitted light. In order to realize a solar cell with high conversion efficiency, the fluorescent material needs to absorb light in a short wavelength region with low photoelectric conversion efficiency in the photoelectric conversion layer and emit light in a long wavelength region with high photoelectric conversion efficiency. is there. In addition, in a solar cell having a photoelectric conversion layer made of single crystal silicon or polycrystalline silicon, although there are some differences, in general, absorption is reduced with respect to light in a wavelength region of 500 nm or less, and in a wavelength region of 400 nm or less. For light, the absorption is further reduced.

FIG. 1 is a diagram showing absorption characteristics (spectral sensitivity characteristics) of a sunlight spectrum in a solar battery cell using single crystal silicon as a photoelectric conversion layer. In FIG. 1, (a) is a spectral sensitivity characteristic when the solar battery cell is a normal cell, and (b) is a spectral sensitivity characteristic when the solar battery cell is a BSF (back surface field) type cell. It is. Here, in the BSF type cell, a P ⁺ type diffusion layer is provided on the back surface of the cell, and loss due to carrier recombination is reduced by a PP ⁺ electric field. As shown in FIG. 1, the absorption characteristics (spectral sensitivity characteristics) with respect to light in the wavelength region of 400 nm or less are extremely small in both cases where the solar battery cell is a normal type or a BSF type. For this reason, the solar cell of the present embodiment photoelectrically converts light in a wavelength region exceeding 400 nm.

  From such a viewpoint, the fluorescent substance added to the solar cell encapsulant in the present embodiment is a fluorescent substance that absorbs light in a wavelength range of 400 nm or less and emits light in a wavelength range of more than 400 nm. Is preferred. By adding such a fluorescent substance to the sealing agent for solar cells, light that cannot be absorbed by the photoelectric conversion layer can be converted into light that can be absorbed by the photoelectric conversion layer.

  Further, the fluorescent material preferably absorbs light in a wavelength range of 350 nm to 400 nm more than light in a wavelength range exceeding 400 nm. This is because even if light in a wavelength region of 400 nm or less is absorbed, if a large amount of light in a wavelength region exceeding 400 nm is absorbed, the total amount of light that can be used in the photoelectric conversion layer is reduced. By absorbing more light in the wavelength range of 350 nm to 400 nm than light in the wavelength range exceeding 400 nm, the light that can be used in the photoelectric conversion layer (direct light) can be used without reducing the wavelength. As a result, the total amount of light that can be used in the photoelectric conversion layer can be increased.

  Further, the fluorescent material is preferably a fluorescent material having a peak in a wavelength region of 400 nm or less in the absorption spectrum and a peak in a wavelength region of 450 nm or more where the sensitivity of the solar cell is high in the emission spectrum. Further, the difference in wavelength between the absorption peak and the emission peak, that is, the Stoke shift is preferably larger than 50 nm. When the fluorescent material is a quantum tod, the stalk shift may not be clear, but even such a stalk shift is effective in increasing the photoelectric conversion efficiency.

  Furthermore, it is preferable that the fluorescent material is a so-called nanoparticle as well as having such absorption characteristics. Specifically, the fluorescent material is preferably nanoparticles having an average particle size of 20 nm or less. Conventionally, the average particle size of a fluorescent material is generally larger than the wavelength of visible light and is larger than a submicron. When a fluorescent substance having a large particle size is used as the sealant, incident sunlight causes light scattering, and as a result, a part of the sunlight does not reach the photoelectric conversion layer, so that high light transmittance (90% or more) Is difficult to achieve, and as a result, the photoelectric conversion efficiency is lowered. Such a decrease in photoelectric conversion efficiency due to light scattering has been one of the reasons why a solar cell employing a wavelength conversion layer using a fluorescent material is difficult to put into practical use. On the other hand, in the sealing agent for solar cells in this Embodiment, by making a fluorescent substance into a nanoparticle with an average particle diameter of 20 nm or less, light scattering is suppressed and most of incident sunlight is effectively used. It becomes possible. Examples of the fluorescent substance having such characteristics include nanoparticles such as CdSe having an average particle diameter of 20 μm or less.

  The transparent resin that disperses or dissolves the fluorescent substance can be any resin material as long as it is a resin material that has sufficient transparency to transmit sunlight. For example, silicone resin, epoxy resin, polyurethane resin, vinyl Resin, styrene elastomer resin (styrene / ethylene-butylene / styrene (SEBS)) and the like. Among them, SEBS is excellent in transparency and handleability, and does not generate an acid unlike ethylene-vinyl acetate copolymer (EVA) and does not adversely affect the fluorescent material. Particularly preferred as a transparent resin.

  When the solar cell encapsulant is formed by dispersing or dissolving a fluorescent substance composed of nanoparticles having an average particle size of 20 nm or less in SEBS, the light transmittance of sunlight is 90% or more, particularly at a wavelength of 600 nm to 800 nm. The light transmittance can be 90% or more, and the light transmittance at a wavelength of 600 nm to 800 nm can be 95% or more.

  Next, a solar cell using the solar cell sealant in the present embodiment will be described. FIG. 2 is a diagram showing a configuration of the solar cell in the present embodiment. The solar cell 1 forms the sealing agent layer 7 which consists of the sealing agent for solar cells in this Embodiment between a pair of transparent protective glass 2 and 3, and seals the photovoltaic cell 4 which has a photoelectric converting layer. Configured by stopping. The solar cells 4 are electrically connected to each other by connection wirings 5, and power is taken out from a terminal box 6 provided on the back side.

  As the photoelectric conversion layer of the solar battery cell 4, a known photoelectric conversion layer such as one using single crystal silicon, one using polycrystalline silicon, or one using amorphous (amorphous) silicon can be applied. Is possible.

  The sealant layer 7 is formed between the transparent protective glass 2 and the transparent protective glass 3. The outer peripheral portion of the sealant layer 7 is fixed to the frame 9 through a seal material 8. Thereby, sunlight passes through the transparent protective glass 2 and the sealant layer 7 on the front side and enters the solar battery cell 4.

  As described above, the solar cell 1 performs photoelectric conversion by using a fluorescent material in the encapsulant layer 7 that absorbs light in a wavelength region of 350 nm to 400 nm more than light in a wavelength region exceeding 400 nm. Wavelength-converted light can also be used without reducing the light available in the layer, and the total amount of light available in the photoelectric conversion layer can be increased. Further, by using nanoparticles having an average particle diameter of 20 nm or less as the fluorescent material, light scattering can be suppressed and most of the incident sunlight can be used effectively. If the encapsulant layer 7 contains a fluorescent material having a normal particle size instead of nanoparticles, it is difficult to make the light transmittance 90% or more due to light scattering. In the encapsulant layer 7, the light transmittance of sunlight can be 90% or more by using nanoparticles having an average particle size of 20 nm or less as the fluorescent material and using SEBS as the transparent resin. In particular, the light transmittance at a wavelength of 600 nm to 800 nm can be 90% or more, and further 95% or more. Thereby, the solar cell 1 can photoelectrically convert a sufficient amount of sunlight in the photoelectric conversion layer of the solar battery cell 4.

  In this way, the solar cell 1 absorbs light in a wavelength region with low photoelectric conversion efficiency, emits light in a wavelength region with high photoelectric conversion efficiency, and further has a light transmittance of 90% at a wavelength of 600 nm to 800 nm. The sealing agent layer 7 having excellent transparency is provided on the light incident side of the solar battery cell 4. As a result, light in a wavelength range that could not contribute to photoelectric conversion can be used effectively for photoelectric conversion, and light in a wavelength range with a high photoelectric conversion rate can also be used effectively for photoelectric conversion. It is possible to realize a solar cell with excellent power generation efficiency.

  Although the present embodiment has been described above, it goes without saying that the present invention is not limited to such an embodiment, and various modifications can be made without departing from the gist of the present invention.

  Next, specific examples of the present invention will be described. The scope of the present invention is not limited to the following examples.

<< 1. Experimental example using solar cells with polycrystalline silicon as the photoelectric conversion layer >>
Example 1
44 μl of fluorescent substance E560 (manufactured by EVIDOT) consisting of CdSe nanoparticles with an average particle diameter of 8 nm was added to 250 mg of SEBS, and 950 μl of toluene was added to prepare a sealant.

  The absorption spectrum of the fluorescent substance E560 is shown in FIG. Moreover, the emission spectrum of the fluorescent substance E560 is shown in FIG. As shown in FIG. 3A, in the absorption spectrum of the fluorescent substance E560, there is an absorption peak in the wavelength region of 350 nm or less, and the absorption in the wavelength region of 350 nm to 400 nm is larger than the absorption in the wavelength region exceeding 400 nm. . Further, as shown in FIG. 3B, in the emission spectrum of the fluorescent material E560, there is a light emission peak in a wavelength region exceeding 500 nm (near the wavelength of 570 nm).

  In the following Comparative Examples 1 and 2, a solar cell sealant using a fluorescent material for dyes was prepared.

(Comparative Example 1)
A fluorescent substance DPhP-C4 for dye use shown in the following [Chemical Formula 1] was prepared. A solar cell sealant was prepared by adding 194 μl of DPhP-C4 to 250 mg of SEBS and adding 800 μl of toluene. The absorption spectrum of this fluorescent substance DPhP-C4 is shown in FIG. In addition, an emission spectrum of the fluorescent substance DPhP-C4 is shown in FIG. As shown in FIG. 4 (a), in the absorption spectrum of the fluorescent substance DPhP-C4, there are absorption peaks in the vicinity of the wavelength of 450 nm and in the vicinity of the wavelength of 435 nm, and the absorption in the wavelength range of 350 nm to 400 nm exceeds Smaller than absorption. In the emission spectrum, the peak position of emission is in the wavelength range of 500 nm or less (near wavelength 480 nm).

(Comparative Example 2)
To 250 mg of SEBS, 44 μl of the fluorescent substance ADS085 for dyes shown in the following [Chemical Formula 2] was added, and 950 μl of toluene was added to prepare a solar cell encapsulant. The absorption spectrum of this fluorescent substance ADS085 is shown in FIG. In addition, an emission spectrum of the fluorescent substance ADS085 is shown in FIG. As shown in FIG. 5A, in the absorption spectrum of the fluorescent substance ADS085, there is an absorption peak near the wavelength of 411 nm, and the absorption in the wavelength range of 350 nm to 400 nm is smaller than the absorption in the wavelength range exceeding 400 nm. As shown in FIG. 5B, in the emission spectrum of the fluorescent substance ADS085, the peak position of the emission is 500 nm or less.

  Next, a solar cell module was prototyped using the sealant prepared in Example 1 and Comparative Examples 1 and 2. Specifically, as shown in FIG. 6, sealing is performed by sandwiching a sealing agent between two transparent protective glasses 12 and 13 on the front surface of a solar cell module 11 including polycrystalline silicon as a photoelectric conversion layer. What formed the agent layer 14 was installed. The sealant layer 14 was formed by applying a sealant with a doctor blade and then sealing in an Ar atmosphere. The thickness of the sealing agent layer 14 was 60 μm. Moreover, the size of the photovoltaic cell of the photovoltaic cell module 11 was set to 65 mm × 41 mm, and the sizes of the transparent protective glasses 12 and 13 were set to 70 mm × 70 mm.

FIG. 7 shows the absorption characteristics (spectral sensitivity) of the solar cell module having such a configuration. In FIG. 7, curves (a) and (b) show the internal quantum efficiency as the spectral sensitivity of the solar cell module provided with SiN, which is polycrystalline silicon, as the photoelectric conversion layer, and the curve (c) The internal quantum efficiency of the solar cell module not equipped with SiN is shown. Here, the curves (a) and (c) are constants Q _f = + 5.0 × 10 ¹¹ , and the curve (b) is constant Q _f = −2.7 × 10 ^11. . The internal quantum efficiency indicates how much the pair of electrons and holes generated by current emits light of the desired wavelength and recombines. The value is specified by the physical property of the material such as 1 and 1 is an ideal value.

  As shown in FIG. 7, in the wavelength range smaller than about 600 nm, the internal quantum efficiency (curves (a) and (b)) of the solar cell module including SiN as a photoelectric conversion layer is a solar cell not including SiN. It is larger than the internal quantum efficiency (curve (c)) of (curve (c)). In a solar cell not provided with SiN, the internal quantum efficiency is drastically reduced particularly at 400 nm or less.

  From these results, the solar cell module has better absorption characteristics (spectral sensitivity) than the case where SiN is not provided by providing SiN which is polycrystalline silicon as a photoelectric conversion layer, particularly in a wavelength region of 400 nm or less. Can be realized.

  Next, photoelectric conversion efficiency was measured for the prototype solar cell module. The measurement results are shown in [Table 1]. In [Table 1], “cell simple substance” measured the photoelectric conversion efficiency in the state of only the solar cell module 11 in which the sealing agent layer 14 sandwiched between the two transparent protective glasses 12 and 13 was not installed. It is a measurement result in the case. “Reference Example 1” and “Reference Example 2” are the first measurement and the second measurement when the photoelectric conversion efficiency is measured for the solar cell module in which the sealant layer 14 is formed of SEBS not containing a fluorescent material. It is a result.

  As shown in [Table 1], in the solar cell provided with polycrystalline silicon as the photoelectric conversion layer, the solar cell of Example 1 had the best photoelectric conversion efficiency value. This is because in Example 1, the fluorescent substance has an absorption peak in a wavelength region of 350 nm or less, and absorbs light in a wavelength region of 350 nm to 400 nm more than light in a wavelength region of more than 400 nm. It is possible to increase the total amount of light that can be used in the conversion layer, and it is possible to effectively use most of incident sunlight by suppressing light scattering by comprising CdSe nanoparticles having an average particle diameter of 8 nm. It was considered that good photoelectric conversion efficiency values were obtained.

≪2. Experimental example using solar cells with single crystal silicon as the photoelectric conversion layer >>
A solar cell module including a solar battery cell having the sealing agent layer of the solar cell sealing agent of the previous Example 1 and Comparative Examples 1 and 2 and having a single crystal silicon as a photoelectric conversion layer was prototyped. Moreover, the sealing agent for solar cells containing the fluorescent substance shown to [Chemical Formula 3] (a), (b) was prepared (it is set as the comparative example 3), and the solar cell module was similarly made as an experiment.

  FIG. 8 shows the configuration of these prototype solar cell modules. The solar cell module shown in FIG. 8 has a structure in which a polyethylene terephthalate film 23 is bonded to the front surface of a solar cell module 21 using single crystal silicon as a photoelectric conversion layer via a sealant layer 22. The thickness of the sealant layer 22 and the thickness of the polyethylene terephthalate film 23 are both 25 μm. The size of the solar cell of the solar cell module 21 is 125 mm × 125 mm, and the size of the polyethylene terephthalate film 23 is 150 mm × 150 mm.

  About the produced solar cell 2, photoelectric conversion efficiency was measured. The results are shown in [Table 2]. In [Table 2], “cell simple substance” is a measurement result when measured only with the solar cell module 21 in which the sealant layer 22 and the polyethylene terephthalate film 23 are not installed, and “Reference Example 3”. These are the measurement results when the sealant layer 22 is formed of SEBS that does not contain a fluorescent material.

  As is clear from the results shown in [Table 2], even in the solar battery cell including polycrystalline silicon as the photoelectric conversion layer, the solar battery using the sealant of Example 1 has the best photoelectric conversion efficiency. A value was obtained. As described above, this is because the fluorescent substance has an absorption peak in a wavelength region of 350 nm or less, and absorbs light in a wavelength region of 350 nm to 400 nm more than light in a wavelength region exceeding 400 nm. It is possible to increase the total amount of light that can be used in the conversion layer, and it is possible to effectively use most of incident sunlight by suppressing light scattering by comprising CdSe nanoparticles having an average particle diameter of 8 nm. It was considered that good photoelectric conversion efficiency values were obtained.

DESCRIPTION OF SYMBOLS 1 Solar cell, 2, 3 Transparent protective glass, 4 Solar cell, 5 Connection wiring, 6 Terminal box, 7 Sealant layer, 8 Seal material, 9 Frame, 11, 21 Solar cell module, 12, 13 Transparent protection Glass, 14,22 Sealant layer, 23 Polyethylene terephthalate film

Claims (10)

A sealing agent for solar cells in which a fluorescent material is dispersed or dissolved in a transparent resin,
The said fluorescent substance absorbs more light of the wavelength range of 350 nm-400 nm than the light of the wavelength range exceeding 400 nm, The sealing compound for solar cells characterized by the above-mentioned.   The encapsulant for solar cell according to claim 1, wherein the fluorescent material has an absorption spectrum peak in a wavelength region of 400 nm or less and an emission spectrum peak in a wavelength region of 500 nm or more.   3. The solar cell encapsulant according to claim 1, wherein an average particle diameter of the fluorescent material is 20 nm or less.   The solar cell sealant according to any one of claims 1 to 3, wherein the light transmittance at a wavelength of 600 nm to 800 nm is 90% or more.   The solar cell encapsulant according to any one of claims 1 to 4, wherein the transparent resin contains styrene / ethylene-butylene / styrene. A solar cell in which a transparent protective glass is bonded to a solar cell having a photoelectric conversion layer via a sealant layer,
The sealant layer is formed of a sealant for solar cells in which a fluorescent material is dispersed or dissolved in a transparent resin,
The said fluorescent substance absorbs more light of the wavelength range of 350 nm-400 nm than the light of the wavelength range exceeding 400 nm, The solar cell characterized by the above-mentioned.   The solar cell according to claim 6, wherein the fluorescent material has an absorption spectrum peak in a wavelength region of 400 nm or less and an emission spectrum peak in a wavelength region of 500 nm or more.   The solar cell according to claim 6 or 7, wherein an average particle diameter of the fluorescent material is 20 nm or less.   The solar cell according to any one of claims 6 to 8, wherein the sealant layer has a light transmittance of 90% or more at a wavelength of 600 nm to 800 nm.   The solar cell according to any one of claims 6 to 9, wherein the transparent resin contains styrene / ethylene-butylene / styrene.

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