JP2010034502A - Wavelength conversion film, solar battery module using same, and method for manufacturing solar battery module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wavelength conversion film, a solar battery module using the same, and a method for manufacturing the solar battery module, of which the configuration is made so as to reduce solar light loss by spectrum mismatch and to have still higher light-transmitting factor of visible light, light use efficiency being made high, allowing the improvement of power generation efficiency. <P>SOLUTION: In the wavelength conversion film 300 containing phospher substance used as one of the light-transmitting layer of the solar battery module having a plurality of light-transmitting layers and solar battery cells 100, the wavelength conversion film is characterized in that the fluorescent substance is composed of coated fluorescent substance particles, each having a fluorescent substance particle and a coating layer covering the surface of the fluorescent substance particle. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wavelength conversion film for a solar cell, a solar cell module using the same, and a method for producing the same. More specifically, the present invention relates to a solar cell module that can increase power generation efficiency by converting light in a wavelength region that does not contribute to power generation into light in a wavelength region that contributes to power generation, a wavelength conversion film used for the solar cell module, and a manufacturing method thereof. Is.

  A schematic view (cross-sectional view) of a conventional silicon crystal solar cell module is shown in FIG. A protective glass (also referred to as cover glass) 201 on the surface uses tempered glass in consideration of impact resistance, and a sealing material 202 (usually also referred to as a resin or filler mainly composed of ethylene vinyl acetate copolymer). In order to improve the adhesion to the surface, one surface is provided with an uneven pattern by embossing.

  Moreover, the uneven | corrugated pattern is formed in the inner side (namely, lower surface of the protective glass 201 in FIG. 3), and the surface of a solar cell module is smooth. Further, a sealing material 202 and a back film 204 for protecting and sealing the solar battery cell 100 and the tab wire 203 are provided below the protective glass 201 (see, for example, Non-Patent Document 1).

  However, in the conventional solar cell module described above, since the difference in refractive index between the solar cell 100 and the sealing material 202 is large, there is a problem that light reflection occurs at the cell-sealing material interface and light cannot be used efficiently.

It has long been known that there is a moth-eye (insect's eye) structure as one of the methods for efficiently taking in external light from all angles including an oblique direction while reducing reflection loss. This is a technology that efficiently incorporates external light by reducing the reflection loss by forming a structure in which transparent objects such as fine cones, triangular pyramids, and quadrangular pyramids are regularly arranged on the surface of the film at a scale of 100 nm. (For example, see Non-Patent Document 2).
Japanese Patent Application Laid-Open No. H10-228473 discloses an improved version of this applied to a solar cell module.

  On the other hand, a layer that emits light in a wavelength region that can contribute to power generation by converting the wavelength of ultraviolet or infrared light that does not contribute to power generation in a sunlight spectrum using a fluorescent material (also referred to as a light emitting material). Many methods have been proposed for providing the solar cell on the light-receiving surface side of the solar cell (see, for example, Patent Documents 2 to 14).

JP 2005-101513 A JP 2000-328053 A JP 09-230396 A JP 2003-243682 A JP 2003-218379 A JP 11-345993 A JP 2006-024716 A Japanese Patent Publication No. 08-004147 JP 2001-094128 A JP 2001-352091 A Japanese Patent Laid-Open No. 10-261811 Japanese Patent No. 2660705 JP 2006-269373 A JP 63-006881 A

Yasuhiro Sasakawa, “Solar Power Generation”-Latest Technology and System, 2000, CMC Corporation Hiroshi Toyoda; “Non-reflective periodic structure”, Optics, Vol. 32, No. 8, p. 489 (2003)

Patent Documents 2 to 14 propose a wavelength conversion of light that does not contribute to power generation into light in a wavelength range that can contribute to power generation, and the wavelength conversion film contains a fluorescent material. When the incident sunlight passes through the wavelength conversion film, it is scattered and does not reach the solar cells sufficiently, and the ratio of not contributing to power generation increases. As a result, even if the wavelength conversion film converts light in the ultraviolet region into light in the visible region, there is a problem that the ratio of the electric power generated with respect to incident sunlight (power generation efficiency) does not increase so much.
In addition, the fluorescent material has no moisture resistance, heat resistance, and the like, and has a problem that it easily deteriorates. Further, when the concentration of the fluorescent substance in the dispersion medium resin is increased, concentration quenching occurs when the concentration is higher than a certain level, and therefore there is a problem that it cannot be used above a certain concentration.

  The present invention is intended to alleviate the above-described problems. By using a fluorescent material that has excellent moisture resistance, heat resistance, good dispersibility, and suppressed concentration quenching, the light utilization efficiency in the solar cell module is improved. The purpose is to improve the power generation efficiency stably. For example, in a silicon crystal solar cell, light having a shorter wavelength than 400 nm and a wavelength longer than 1200 nm are not effectively used in sunlight, and about 56% of solar energy is sunlight due to this spectrum mismatch. Does not contribute to power generation. The present invention is to overcome spectral mismatch by using a fluorescent material with excellent moisture resistance and heat resistance, good dispersibility, and no concentration quenching, wavelength conversion, and efficient and stable use of sunlight. That's it.

  That is, the wavelength conversion film of the present invention is intended to contain a fluorescent material that is excellent in moisture resistance and heat resistance, has good dispersibility, and does not cause concentration quenching. In addition, the wavelength conversion film of the present invention efficiently converts light that does not contribute to photovoltaic power generation into incident light that contributes to power generation, and at the same time, efficiently introduces the light into a solar cell without scattering. The purpose is to do.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have used a fluorescent substance particle having a fluorescent substance particle and a coating layer covering the periphery of the fluorescent substance particle as a wavelength conversion film. It is possible to provide a wavelength conversion film that is excellent in moisture resistance and heat resistance, has good dispersibility, and does not cause concentration quenching, at the same time as converting light that does not contribute to solar power generation into a wavelength that contributes to power generation. I found it.
In addition, by making the refractive index of the dispersion medium resin of the wavelength conversion film and the coating layer of the coated fluorescent substance particles within a certain range, the incident sunlight is not scattered by the fluorescent substance and the efficiency is improved to the solar cell. The inventors have found that it can be introduced well, and have completed the present invention.
That is, the present invention is as follows.

(1) In a wavelength conversion film containing a fluorescent material and a dispersion medium resin, which is used as one of light transmissive layers of a solar battery module having a plurality of light transmissive layers and solar cells,
The wavelength conversion film, wherein the fluorescent substance is a coated fluorescent substance particle having a fluorescent substance particle and a coating layer covering the periphery of the fluorescent substance particle.

(2) The wavelength conversion film is disposed on the light receiving surface of the solar battery cell, the coating layer has a refractive index of 1.5 to 2.1, and the dispersion medium resin has a refractive index of 1.5 to 2.1. 2.1, and the plurality of light transmissive layers are layer 1, layer 2,..., Layer m from the light incident side, and their refractive indexes are n1, n2,. The wavelength conversion film as described in (1) above, wherein n1 ≦ n2 ≦... ≦ nm holds.

(3) The wavelength conversion film as described in (1) or (2) above, wherein the coating layer is silica glass formed by a sol-gel method.

(4) The wavelength conversion film according to any one of (1) to (3), wherein the fluorescent substance is a europium complex.

(5) A solar cell module having the wavelength conversion film according to any one of (1) to (4) above.

(6) A fluorescent material particle coating step of coating fluorescent material particles with silica glass by a sol-gel reaction using silicon alkoxide to obtain coated fluorescent material particles having a coating layer;
A film forming step of dispersing the coated fluorescent substance particles in a dispersion medium resin to produce a resin composition, and using the resin composition to form a wavelength conversion film, of (1) to (4) above The manufacturing method of the wavelength conversion film as described in any one.

(7) In the manufacturing method of the solar cell module which has a some light transmissive layer and a photovoltaic cell, the wavelength conversion film as described in any one of said (1)-(4) is laminated | stacked, and the said light The manufacturing method of the solar cell module characterized by having the process of comprising one of the permeable layers.

  According to the present invention, when applied to a solar cell module, the fluorescent material for converting light that does not contribute to solar power generation into a wavelength that contributes to power generation among incident sunlight is excellent in moisture resistance and heat resistance. Since the dispersibility is good and concentration quenching does not occur, a wavelength conversion film that can use sunlight efficiently and stably can be provided. Moreover, the wavelength conversion film which can introduce | transduce sunlight to a photovoltaic cell efficiently without scattering can be provided.

It is the schematic at the time of incorporating the wavelength conversion type light trapping film of this invention in a module. It is the schematic for demonstrating the process of forming a wavelength conversion type light trapping film in a photovoltaic cell. It is a structural view (cross-sectional view) of a conventional solar cell module.

<Wavelength conversion film and production method thereof>
The wavelength conversion film of the present invention is used as one of the light transmissive layers of a solar cell module having a plurality of light transmissive layers and solar cells, and includes a fluorescent material and a dispersion medium resin, The fluorescent substance particles are characterized by being coated fluorescent substance particles having fluorescent substance particles and a coating layer covering the periphery of the fluorescent substance particles. Thereby, the moisture resistance and heat resistance of the phosphor particles are improved, the dispersibility is good, and the concentration quenching can be suppressed.

  The refractive index of the coating layer of the coated fluorescent substance particles and the dispersion medium resin of the wavelength conversion film is preferably 1.5 to 2.1, respectively, and the plurality of light transmissive layers are formed from the light incident side. 1, layer 2,..., Layer m, and n 1, n 2,..., Nm, it is preferable that n 1 ≦ n 2 ≦. Moreover, it is more preferable to reduce the difference in refractive index between the coating layer and the dispersion medium resin because the scattering loss of sunlight can be reduced. If the refractive index does not satisfy this, reflection at the layer interface tends to increase, and light loss tends to increase.

That is, in the wavelength conversion film of the present invention, the external light entering from all angles has less reflection loss and is efficiently introduced into the solar battery cell, so that the refractive index of the wavelength conversion film is closer to the light incident side than the wavelength conversion film. The light transmissive layer disposed, that is, the light transmissive layer disposed higher than the refractive index of the antireflection film, the protective glass, the sealing material, the mold film, and the like, and disposed on the light incident side of the wavelength conversion film, The refractive index is preferably lower than the refractive index of the SiNx: H layer (also referred to as “cell antireflection film”) and the Si layer of the solar battery cell.
Specifically, the light-transmitting layer disposed on the light incident side from the wavelength conversion film, that is, the refractive index of the antireflection film is 1.25 to 1.45, protective glass, sealing material, mold film, etc. A refractive index of about 1.45 to 1.55 is usually used. The light-transmitting layer disposed on the light incident side of the wavelength conversion film, that is, the refractive index of the SiNx: H layer (cell antireflection film) of the solar battery cell is usually about 1.9 to 2.1 and the Si layer A refractive index of about 3.3 to 3.4 is usually used. From the above, the refractive index of the wavelength conversion film of the present invention is 1.5 to 2.1, preferably 1.5 to 2.1.

In addition, the preferable refractive index of the other layer of a light transmissive layer is as showing below. For example, when the three layers from the light incident side of the light transmissive layer are a layer, b layer, and c layer, the refractive indexes na, nb, and nc of the respective layers satisfy or approximate the following formula: Is preferred.
nb = √na · nc

  In the present invention, the normalized light absorption coefficient a of the wavelength conversion film represented by the following formula (1) is preferably 0.1 to 0.1 when the wavelength of incident light is 400 to 1200 nm. When a is in the above range, the same light transmittance as that of the protective glass and the sealing material can be obtained, and the light absorption loss due to the wavelength conversion film need not be taken into consideration.

（ただし、Ｔは光透過率、Ｌはフィルム平均厚み（μｍ）である。）

(However, T is the light transmittance, and L is the average film thickness (μm).)

  In addition, the light transmittance of T is the light transmittance of the material itself in the state without the unevenness | corrugation of a wavelength conversion film. The film average thickness of L is the average thickness of the wavelength conversion film material.

  The refractive index of the phosphor particles is a value unique to the material, and the refractive index of the phosphor particles is generally about 1.5. As the dispersion medium resin of the wavelength conversion film, since 1.5 to 2.1 is practically used, in order to reduce the difference in refractive index between the fluorescent substance particles and the dispersion medium resin, Scattering of sunlight by Rayleigh scattering can be achieved by using a coating layer material having the same refractive index (refractive index of 1.5 to 2.1) and reducing the difference in refractive index between the coated phosphor particles and the dispersion medium resin. This is preferable from the viewpoint of reducing loss.

  The scattering of light correlates with the coated phosphor material particles in the film, that is, the difference in refractive index between the coating layer and the dispersion medium resin, and the particle size of the coated phosphor material particles. Specifically, if the difference between the refractive index of the coating layer and the refractive index of the dispersion medium resin is small, the light scattering is not significantly affected by the particle size of the coated fluorescent substance particles, and the light scattering is also small. It becomes. However, if the difference between the refractive index of the coating layer and the refractive index of the dispersion medium resin increases, the light scattering is affected by the size of the particle diameter of the coated fluorescent material particles, so that the particle diameter is as small as possible. It is preferable that

  Here, the relationship between the particle diameter of the coated fluorescent material particles and the refractive index of the coating layer in Rayleigh scattering of the coated fluorescent material particles (light scattering by particles having a size smaller than the wavelength of light) is shown in the following equation.

As can be seen from the above formula, the scattering can be reduced by setting the refractive index of the coated fluorescent substance particles (that is, the refractive index of the coating layer material) and the refractive index of the dispersion medium resin to the same level.
It can also be seen from the above formula that the loss of sunlight due to scattering can be made smaller by reducing the particle diameter of the coated phosphor particles. Specifically, it is preferable that a primary particle diameter of the coated fluorescent substance particle is 100 nm or less.

  In addition, the particle size (primary particle diameter) of the coated fluorescent substance particles coated with the coating layer material used for the wavelength conversion film of the present invention is 1 to the light wavelength in order to sufficiently reduce the scattering loss due to Rayleigh scattering. Desirably smaller than / 3. That is, since the light in the ultraviolet region is about 400 nm, the primary particle size of the coated phosphor particles is required to be 100 nm or less.

The present invention is preferably silica glass formed on a fluorescent material surface by a sol-gel method using silicon alkoxide as a coating layer material used for a wavelength conversion film. By using the sol-gel method, the coated phosphor particles can be formed at a low temperature and with a simple process, so that a wavelength conversion type trapping film can be manufactured at a low cost.
Here, “silica glass” may appropriately contain titanium oxide, niobium oxide, alumina, silicon nitride, silicon oxynitride, or the like.

  There is a problem that the fluorescent substance is generally deteriorated by oxygen or moisture, and the wavelength conversion efficiency is deteriorated with time. Therefore, by covering the periphery of the phosphor particles with silica glass as a coating layer material, an effect is obtained that the silica glass blocks oxygen and moisture and prevents the wavelength conversion efficiency of the phosphor from deteriorating.

The method for coating the phosphor particles with silica glass by the sol-gel method may be performed by a known method, and there is no particular limitation. By treating the phosphor particles with silicon alkoxide in a solvent, It can be carried out.
Although the refractive index of silica glass is about 1.45, it is appropriately adjusted to include titanium oxide, niobium oxide, alumina, silicon nitride, silicon oxynitride and the like so that the refractive index of the dispersion medium resin is about the same. It is also preferable.

  Moreover, it is also preferable to mix a dissimilar metal with silica glass. Specifically, the refractive index of the coating layer material is adjusted to be approximately the same as the refractive index of the material preferably used as the dispersion medium resin.

  Dissimilar metals to be blended with silica glass include Ti, Ta, Ge, Zn, Zr, Al, Sb, Be, Cd, Cr, Sn, Cu, Ga, Mn, Fe, Mo, V, W, and Ce. It is done.

Silica glass containing a different metal is obtained by adjusting the amount to adjust to the target refractive index, mixing the metal alkoxide of the different metal with silicon alkoxide, and causing the sol-gel reaction to the mixture.
M (OR) n is mentioned as a metal alkoxide of a different metal. M is a metal, n is its valence, R is an organic group having 1 to 10 carbon atoms, and R may be all the same or different.

  The method of coating the phosphor particles with silica glass by the sol-gel method is not particularly limited, but the phosphor particles are dissolved in a suitable solvent and separately stirred for sol-gel using silicon alkoxide, alcohol solvent, and water. Make a solution. Here, the previously prepared phosphor material solution is added, stirred well, and the catalyst is added. It stirs until a white precipitate is seen in the solution, transfers it onto a vat such as glass or Teflon (registered trademark), heats it at about 80 to 120 ° C. for 2 hours or more, and dries it.

As a solvent used in the sol-gel method, a mixed solution of water and an organic solvent is used. Examples of the organic solvent include dimethylformamide (DMF), tetrahydrofuran (THF), alcohols such as methanol and ethanol, chloroform, toluene and the like.
In addition, the confirmation that the coating layer is formed around the fluorescent substance particles is indirect, but, for example, the high temperature and high humidity resistance is measured under the conditions of 85 ° C. and 85% RH, and the fluorescent substance particles before the coating layer is formed. Judged by the presence or absence of improvement in high temperature and high humidity resistance.

  Examples of the silicon alkoxide used in the sol-gel method include tetraalkoxysilane, trialkoxysilane, and diorganodialkoxysilane.

  Examples of the tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetra-iso-propoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, and tetra-tert-butoxysilane. And tetraphenoxysilane.

  Examples of the trialkoxysilane include trimethoxysilane, triethoxysilane, tripropoxysilane, fluorotrimethoxysilane, fluorotriethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltri-n-propoxysilane, and methyltri-iso. -Propoxysilane, methyltri-n-butoxysilane, methyltri-iso-butoxysilane, methyltri-tert-butoxysilane, methyltriphenoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltri-n-propoxysilane, ethyltri-iso -Propoxysilane, ethyltri-n-butoxysilane, ethyltri-iso-butoxysilane, ethyltri-tert-butoxysilane, ethyltriphenoxy N-propyltrimethoxysilane, n-propyltriethoxysilane, n-propyltri-n-propoxysilane, n-propyltri-iso-propoxysilane, n-propyltri-n-butoxysilane, n-propyltri -Iso-butoxysilane, n-propyltri-tert-butoxysilane, n-propyltriphenoxysilane, iso-propyltrimethoxysilane, iso-propyltriethoxysilane, iso-propyltri-n-propoxysilane, iso-propyl Tri-iso-propoxysilane, iso-propyltri-n-butoxysilane, iso-propyltri-iso-butoxysilane, iso-propyltri-tert-butoxysilane, iso-propyltriphenoxysilane, n-butyltrimethyl Xylsilane, n-butyltriethoxysilane, n-butyltri-n-propoxysilane, n-butyltri-iso-propoxysilane, n-butyltri-n-butoxysilane, n-butyltri-iso-butoxysilane, n-butyltri-tert -Butoxysilane, n-butyltriphenoxysilane, sec-butyltrimethoxysilane, sec-butyltriethoxysilane, sec-butyltri-n-propoxysilane, sec-butyltri-iso-propoxysilane, sec-butyltri-n-butoxy Silane, sec-butyltri-iso-butoxysilane, sec-butyltri-tert-butoxysilane, sec-butyltriphenoxysilane, t-butyltrimethoxysilane, t-butyltriethoxysilane, t-butylto Ri-n-propoxysilane, t-butyltri-iso-propoxysilane, t-butyltri-n-butoxysilane, t-butyltri-iso-butoxysilane, t-butyltri-tert-butoxysilane, t-butyltriphenoxysilane, Phenyltrimethoxysilane, phenyltriethoxysilane, phenyltri-n-propoxysilane, phenyltri-iso-propoxysilane, phenyltri-n-butoxysilane, phenyltri-iso-butoxysilane, phenyltri-tert-butoxysilane, Phenyltriphenoxysilane, trifluoromethyltrimethoxysilane, pentafluoroethyltrimethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriethoxy Run, and the like.

  Examples of the diorganodialkoxysilane include dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldi-n-propoxysilane, dimethyldi-iso-propoxysilane, dimethyldi-n-butoxysilane, dimethyldi-sec-butoxysilane, and dimethyldi-tert. -Butoxysilane, dimethyldiphenoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldi-n-propoxysilane, diethyldi-iso-propoxysilane, diethyldi-n-butoxysilane, diethyldi-sec-butoxysilane, diethyldi-tert- Butoxysilane, diethyldiphenoxysilane, di-n-propyldimethoxysilane, di-n-propyldiethoxysilane, di-n-propyldi-n-propoxy Di-n-propyldi-iso-propoxysilane, di-n-propyldi-n-butoxysilane, di-n-propyldi-sec-butoxysilane, di-n-propyldi-tert-butoxysilane, di-n- Propyl diphenoxy silane, di-iso-propyl dimethoxy silane, di-iso-propyl diethoxy silane, di-iso-propyl di-n-propoxy silane, di-iso-propyl di-iso-propoxy silane, di-iso-propyl di- n-butoxysilane, di-iso-propyldi-sec-butoxysilane, di-iso-propyldi-tert-butoxysilane, di-iso-propyldiphenoxysilane, di-n-butyldimethoxysilane, di-n-butyldi Ethoxysilane, di-n-butyldi-n-propoxy Silane, di-n-butyldi-iso-propoxysilane, di-n-butyldi-n-butoxysilane, di-n-butyldi-sec-butoxysilane, di-n-butyldi-tert-butoxysilane, di-n- Butyldiphenoxysilane, di-sec-butyldimethoxysilane, di-sec-butyldiethoxysilane, di-sec-butyldi-n-propoxysilane, di-sec-butyldi-iso-propoxysilane, di-sec-butyldi- n-butoxysilane, di-sec-butyldi-sec-butoxysilane, di-sec-butyldi-tert-butoxysilane, di-sec-butyldiphenoxysilane, di-tert-butyldimethoxysilane, di-tert-butyldi Ethoxysilane, di-tert-butyldi-n-propoxysila Di-tert-butyldi-iso-propoxysilane, di-tert-butyldi-n-butoxysilane, di-tert-butyldi-sec-butoxysilane, di-tert-butyldi-tert-butoxysilane, di-tert- Butyldiphenoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, diphenyldi-n-propoxysilane, diphenyldi-iso-propoxysilane, diphenyldi-n-butoxysilane, diphenyldi-sec-butoxysilane, diphenyldi-tert -Butoxysilane, diphenyldiphenoxysilane, bis (3,3,3-trifluoropropyl) dimethoxysilane, methyl (3,3,3-trifluoropropyl) dimethoxysilane and the like.

  Examples of compounds other than the above include bis (trimethoxysilyl) methane, bis (triethoxysilyl) methane, bis (tri-n-propoxysilyl) methane, bis (tri-iso-propoxysilyl) methane, and bis (tri Methoxysilyl) ethane, bis (triethoxysilyl) ethane, bis (tri-n-propoxysilyl) ethane, bis (tri-iso-propoxysilyl) ethane, bis (trimethoxysilyl) propane, bis (triethoxysilyl) propane Bis (tri-n-propoxysilyl) propane, bis (tri-iso-propoxysilyl) propane, bis (trimethoxysilyl) benzene, bis (triethoxysilyl) benzene, bis (tri-n-propoxysilyl) benzene, Bis (tri-iso-propoxysilyl) Bis silyl alkanes such as Zen, and a bis silyl benzene.

  Further, for example, hexaalkoxydisilanes such as hexamethoxydisilane, hexaethoxydisilane, hexa-n-propoxydisilane, hexa-iso-propoxydisilane, 1,2-dimethyltetramethoxydisilane, 1,2-dimethyltetraethoxydisilane, And dialkyltetraalkoxydisilanes such as 1,2-dimethyltetrapropoxydisilane.

A compound (halogenated silane) in which the hydrolyzable group X is a halogen atom (halogen group) can also be used. Specifically, for example, a halogen in which the alkoxy group in each alkoxysilane molecule described above is substituted with a halogen atom. Silane or the like.
Furthermore, a compound in which the hydrolyzable group X is an acetoxy group (acetoxysilane) can also be used. Specifically, for example, acetoxysilane in which the alkoxy group in each alkoxysilane molecule described above is substituted with an acetoxy group, etc. Can be mentioned. Furthermore, a compound (isocyanate silane) in which the hydrolyzable group X is an isocyanate group can also be used. Specifically, for example, an isocyanate silane in which the alkoxy group in each alkoxysilane molecule described above is substituted with an isocyanate group, etc. Is mentioned.
Furthermore, a compound (hydroxysilane) in which the hydrolyzable group X is a hydroxyl group can also be used. Specifically, for example, hydroxysilane in which the alkoxy group in each alkoxysilane molecule described above is substituted with a hydroxyl group, etc. Is mentioned.

These silicon alkoxides are used alone or in combination of two or more.
Also, resins obtained by hydrolytic condensation of partial condensates such as silicon alkoxide multimers, resins obtained by hydrolytic condensation of partial condensates such as silicon alkoxide multimers and silicon alkoxide, silicon alkoxides and others Resins obtained by hydrolytic condensation with the above compounds, partial condensates such as silicon alkoxide multimers and other compounds (compounds that can cause partial condensation with silicon alkoxides, specifically compounds having OH groups) It is also possible to use a resin obtained by hydrolytic condensation of

  Examples of partial condensates such as silicon alkoxide multimers include hexaalkoxydisiloxanes such as hexamethoxydisiloxane, hexaethoxydisiloxane, hexa-n-propoxydisiloxane, hexa-iso-propoxydisiloxane, and partial condensation. Advanced trisiloxanes, tetrasiloxanes, oligosiloxanes and the like.

In addition, as a fluorescent substance, a europium complex is preferable. Specifically, in addition to the central element europium (Eu), a molecule to be a ligand is necessary. However, in the present invention, the ligand is not limited and may be a molecule that forms a complex with europium. Anything is fine. As an example of a fluorescent substance composed of such a europium complex, N.I. Kamata, D.H. Terunuma, R.A. Ishii, H.M. Satoh, S .; Aihara, Y. et al. Yaoita, S .; Tonsyo, J .; Organometallic Chem. , 685, 235, 2003. Eu (TTA) ₃ phen etc. mentioned in the above are usable. A method for producing Eu (TTA) ₃ Phen is described, for example, in Masa Mitsui, Shinji Kikuchi, Tokuji Miyashita, Yutaka Amano, J. et al. Mater. Chem. Reference may be made to the method disclosed in 2003, 13, 285-2879.

  By using the europium complex, a solar cell module having high power generation efficiency can be realized. The europium complex converts light in the ultraviolet region into light in the red wavelength region with high wavelength conversion efficiency, and the converted light contributes to power generation in the solar battery cell.

The method for measuring the primary particle diameter of the coated fluorescent substance particles can be performed using, for example, an electron microscope.
In order to set the primary particle diameter of the coated fluorescent substance particles obtained by the sol-gel method to 100 nm, the reaction time, temperature, blending ratio, type of solvent, catalyst, etc. in the sol-gel method may be appropriately adjusted.

As will be described later, the wavelength conversion film of the present invention is prepared by mixing the coated fluorescent substance particles and the dispersion medium resin to prepare a resin composition, which is then formed into a film. The wavelength conversion film of the present invention preferably has a fine concave or convex shape having a polygonal pyramid or cone.
It is not necessary to have fine concave or convex polygonal pyramids or cones. In this case, the manufacturing process is simplified.

As described above, the light-transmitting layer disposed on the light incident side from the wavelength conversion film, that is, the refractive index of the antireflection film is 1.25 to 1.45, protective glass, sealing material, mold film, etc. A refractive index of about 1.45 to 1.55 is usually used. The light-transmitting layer disposed on the light incident side of the wavelength conversion film, that is, the refractive index of the SiNx: H layer (cell antireflection film) of the solar battery cell is usually about 1.9 to 2.1 and the Si layer A refractive index of about 3.3 to 3.4 is usually used. From the above, the refractive index of the wavelength conversion film of the present invention is 1.5 to 2.1, preferably 1.5 to 2.1.
In order to set the refractive index of the wavelength conversion film to 1.5 to 2.1, the refractive index of the dispersion medium resin and the coated fluorescent substance particles may be set within this range.

  It is desired that the coated fluorescent material particles introduced into the dispersion medium resin of the film have little light scattering. For that purpose, it is preferable to adjust so that the refractive index of a coating layer material may be matched with the material (refractive index 1.5-2.1) preferably used as a dispersion medium resin of a wavelength conversion film.

In the present invention, those having a refractive index of 1.5 to 2.1 used as the dispersion medium resin are listed below.
Poly (2,6-dichlorostyrene) (1.625), poly (2,6-diphenyl-1,4-phenylene oxide) (1.64), poly (2-chlorostyrene) (1.610), poly (2-vinylnaphthalene) (1.682), poly (2-vinylthiophene) (1.638), poly (α-methylstyrene) (1.61), poly (α-naphthylcarbanyl methacrylate) (1. 63), poly (α-naphthyl methacrylate) (1.641), poly (chloro-p-xylene) (1.629), poly (styrene sulfide) (1.657), poly (sulfone) [poly [4, 4′-isopropylidenediphenoxydi (4-phenylene) sulfide]] (1.633).
In addition, an organic-inorganic hybrid resin can be used, and specifically, a titanium oxide hybrid resin can be used. As the titanium oxide hybrid resin, other resins, for example, resin compositions described in JP-A-2008-297537 and JP-A-2008-255124 can be used.

  In the present invention, a solar cell module includes an antireflection film, a protective glass, a sealing material, a wavelength conversion film, a mold film that serves as a mold for forming a concave or convex portion of the wavelength conversion film, a solar cell, a back film, and a cell electrode. , Composed of necessary members in a tab line or the like. Among these members, the light-transmitting layer having light transmittance includes an antireflection film, a protective glass, a sealing material, the wavelength conversion film of the present invention, a mold film, and a SiNx: H layer of a solar cell (cell reflection). Prevention film) and Si layer.

  In the present invention, the order of lamination of the light-transmitting layers mentioned above is usually an antireflection film, a protective glass, a sealing material, and a mold that is formed if necessary, in order from the light receiving surface of the solar cell module. The film, the wavelength conversion film of the present invention, the SiNx: H layer (cell antireflection film) of the solar battery cell, and the Si layer.

  In addition, it is preferable that the wavelength conversion film of this invention is arrange | positioned on the light-receiving surface of a photovoltaic cell. By doing so, it can follow the uneven | corrugated shape including a cell electrode etc. of a photovoltaic cell light-receiving surface without gap.

The wavelength conversion film of the present invention is used as one of the light transmissive layers of a solar cell module having a plurality of light transmissive layers and solar cells, and more specifically, one side is a solar cell. The surface (light-receiving surface) follows the uneven shape of the surface without a gap, and the other surface is formed so as to spread a large number of fine convex or concave shapes without a gap, and the shape of each of the fine concave or convex portions is a cone having substantially the same shape. Or a polygonal pyramid having a refractive index of 1.5 to 2.1 and containing the coated phosphor particles, and a plurality of light-transmitting layers from the light incident side to layer 1, layer 2,. -It is the wavelength conversion film characterized by satisfying n1 <= n2 <= ... <= nm, when it is set as the layer m and these refractive indexes are set to n1, n2, ... nm.
Further, the present invention provides a wavelength conversion film with a mold film used for a solar cell module, that is, the wavelength conversion film, and the minute concave or convex side of the wavelength conversion film, complementary to the fine concave or convex portion (no gap). A mold film (a mold film that serves as a mold for forming a concave or convex portion of a film) in which a large number of fine convexities or concave portions that are completely meshed and bonded are formed without gaps, and the refractive index thereof is smaller than the refractive index of the wavelength conversion film. And a film with a mold film having a smooth appearance is also provided. In addition, a type | mold film is used as a casting_mold | template for forming so that many convex or concave polygonal pyramids or cones of the wavelength conversion film of this invention may be spread over a light-receiving surface without gap.

  In the wavelength conversion film of the present invention, the plurality of light transmissive layers are layer 1, layer 2,..., Layer m from the light incident side, and the refractive indexes thereof are n1, n2,. In this case, it is preferable that n1 ≦ n2 ≦. If the refractive index does not satisfy this, reflection at the layer interface tends to increase, and light loss tends to increase.

  In order to efficiently introduce incident light from any angle into the solar battery cell, it is advantageous that the fine convex or concave polygonal pyramid or conical surface of the wavelength conversion film has a narrow apex angle. When there is a reflection loss at the interface between the solar cell and the solar cell, the reflected light leaks to the outside again if the apex angle is too narrow.

  In order to reflect the reflected light and the wavelength-converted light again by the wavelength conversion film and successfully introduce them into the solar battery cell, the apex angle is preferably 75 to 150 degrees, and most preferably, the apex angle is ideally 90 Good. If the apex angle is 90 degrees, it can be said that the angle is the best in terms of performance and processing accuracy.

  According to the literature, eg Hiroshi Toyoda; “Non-reflective periodic structure”, Optics, Vol. 32, No. 8, page 489 (2003), the size of the base is the value obtained by dividing the shortest wavelength to be used by the refractive index of the material. For example, when the refractive index is 2.0, the solar cell module has a thickness of about 175 nm. However, in order to obtain such a fine structure, the processing method is also limited. Therefore, the present invention does not require such an ultrafine structure. Therefore, considering the ease of processing, it is preferably 1 to 1000 μm, and more preferably 10 to 100 μm.

  The thickness of the wavelength conversion film of the present invention is considered by dividing the wavelength conversion film into a pedestal portion and a fine convex or concave polygonal pyramid or cone portion. Since it is necessary to follow the uneven shape of the solar battery cell and embed it, the thickness of the pedestal portion must be equal to or greater than the unevenness of the solar battery cell. In addition, the unevenness | corrugation of this photovoltaic cell includes the cell electrode of a photovoltaic cell, a tab wire, etc.

  Usually, the surface of the solar battery cell is textured, and the depth is 0 to 20 μm. On the other hand, in order to reduce reflection loss from external light on the wavelength conversion film, the height of fine concave or convex polygonal pyramids or cones formed so as to be regularly laid out without gaps is mainly due to processing. 1-100 μm from the request. Specifically, the thickness of the pedestal portion of the wavelength conversion film of the present invention is larger than the depth of 0 to 20 μm of the texture structure on the surface of the solar battery cell, and the thickness of the fine concave portion or convex portion of the wavelength conversion film is processed. It is preferable to set it as 1-100 micrometers from the said request | requirement.

  One side of the wavelength conversion film of the present invention follows the unevenness of the surface (light receiving surface) of the solar cell without gaps, and is usually bonded onto the solar cell 100 as shown in FIG. On the surface having a fine convex or concave polygonal pyramid or cone, the mold film used to form the fine convex or concave polygonal pyramid or cone on the film is removed, and the sealing material 202 is laminated to form a void. A mold used to fill a fine convex or concave polygonal pyramid or cone of the wavelength conversion film 300 without gaps, or to form a fine convex or concave polygonal pyramid or cone in a film. The film may be left without being removed. In FIG. 1, connection tab lines and electrodes are omitted, but the wavelength conversion film of the present invention is a solar cell light receiving surface that is the other surface having a fine convex or concave polygonal pyramid or cone. In terms of surface, it is preferable that the connection tab line and the uneven shape of the electrode can be followed without a gap.

The wavelength conversion film follows the unevenness of the solar battery cell on one side as described above, and is preferably provided on the other side in order to reduce reflection loss from external light. Fine concave or convex polygonal pyramids or cones formed so as to be laid out without gaps are transferred. Therefore, when forming a wavelength conversion film, it is important to use the resin composition containing the said covering fluorescent substance particle in a semi-hardened state. As the dispersion medium resin of the resin composition, a photo-curing resin, a thermosetting resin, a thermoplastic resin that flows by heating or pressurization, which can easily give a fine convex or concave polygonal pyramid or cone, alone or in combination Used. Among them, an organic-inorganic hybrid composition containing titanium tetraalkoxide obtained by a sol-gel method is preferable as a resin composition, which exhibits shape transferability.
In any case, for the wavelength conversion, the coated fluorescent material particles, preferably coated fluorescent material particles containing a europium complex, are contained in the resin composition.

  In the resin composition for a wavelength conversion film of the present invention, a preferable blending amount of the coated fluorescent substance particles is preferably 0.001 to 5% by mass in terms of elemental mass concentration of europium. If it is 0.001% by mass or less, the luminous efficiency tends to be low, and if it is 5% by mass or more, the luminous efficiency tends to decrease due to concentration quenching.

  As described above, a photocurable resin, a thermosetting resin, a thermoplastic resin, or the like is preferably used as the dispersion medium resin of the resin composition. When using a photocurable resin for the dispersion medium resin of the resin composition for wavelength conversion films, the resin configuration of the photocurable resin and the photocuring method are not particularly limited. For example, in the photocuring method using a photoradical initiator, the resin composition for a wavelength conversion film includes (A) a photocurable resin (dispersion medium resin), (B) a crosslinkable monomer, and (C And) a photoinitiator that generates free radicals by light.

Here, (A) a photocurable resin (dispersion medium resin) is a copolymer obtained by copolymerizing acrylic acid or methacrylic acid and alkyl esters thereof and other vinyl monomers copolymerizable therewith as constituent monomers. Coalescence is used. These copolymers can be used alone or in combination of two or more. Examples of the alkyl acrylate ester or alkyl methacrylate ester include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, and the like. Acrylic acid unsubstituted alkyl ester or methacrylic acid unsubstituted alkyl ester, acrylic acid substituted alkyl ester or methacrylic acid substituted alkyl ester in which a hydroxyl group, an epoxy group, a halogen group or the like is substituted on these alkyl groups.
Examples of other vinyl monomers that can be copolymerized with acrylic acid, methacrylic acid, alkyl acrylate ester, or alkyl methacrylate ester include acrylamide, acrylonitrile, diacetone acrylamide, styrene, vinyl toluene, and the like. These vinyl monomers can be used alone or in combination of two or more. Moreover, it is preferable that the weight average molecular weight of (A) component dispersion medium resin is 10,000-300,000 from the point of coating-film property, coating-film strength, and developability.

(B) As a crosslinkable monomer, for example, dicyclopentenyl (meth) acrylate; tetrahydrofurfuryl (meth) acrylate; benzyl (meth) acrylate; obtained by reacting a polyhydric alcohol with an α, β-unsaturated carboxylic acid. Compounds such as polyethylene glycol di (meth) acrylate (having 2 to 14 ethylene groups), trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane ethoxytri (meta ) Acrylate, trimethylolpropane propoxy tri (meth) acrylate, tetramethylol methane tri (meth) acrylate, tetramethylol methane tetra (meth) acrylate, polypropylene glycol di (meth) acrylate (propylene) Dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, bisphenol A polyoxyethylene di (meth) acrylate, bisphenol A dioxyethylene di (meth) Acrylate, bisphenol A trioxyethylene di (meth) acrylate, bisphenol A decaoxyethylene di (meth) acrylate, etc.); compounds obtained by adding an α, β-unsaturated carboxylic acid to a glycidyl group-containing compound (for example, tri Methylolpropane triglycidyl ether triacrylate, bisphenol A diglycidyl ether diacrylate, etc.); a substance having a polyvalent carboxylic acid (for example, phthalic anhydride) and a hydroxyl group and an ethylenically unsaturated group (for example, β-hydroxy ester) (Meth) acrylate); alkyl esters of acrylic acid or methacrylic acid (for example, (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid butyl ester, (meth) acrylic Acid 2-ethylhexyl ester); urethane (meth) acrylate (for example, reaction product of tolylene diisocyanate and 2-hydroxyethyl (meth) acrylic acid ester, trimethylhexamethylene diisocyanate, cyclohexanedimethanol and 2-hydroxyethyl (meth)) A reaction product with an acrylic ester, etc.);
Particularly preferred (B) crosslinkable monomers include trimethylolpropane tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and bisphenol A polyoxyethylene dimethacrylate. In addition, the said compound is used individually or in combination of 2 or more types.

  In particular, when increasing the refractive index of the wavelength conversion film, it is advantageous that (A) the dispersion medium resin and / or (B) the crosslinkable monomer contain bromine and sulfur atoms. Examples of bromine-containing monomers include New Frontier BR-31, New Frontier BR-30, and New Frontier BR-42M manufactured by Daiichi Kogyo Seiyaku. Examples of the sulfur-containing monomer composition include IU-L2000, IU-L3000, and IU-MS1010 manufactured by Mitsubishi Gas Chemical Company. However, the bromine and sulfur atom-containing monomers (polymers containing them) used in the present invention are not limited to those listed here.

  (C) The photoinitiator is preferably a photoinitiator that generates free radicals by ultraviolet light or visible light. For example, benzoin ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isobutyl ether, and benzoin phenyl ether Benzophenones such as benzophenone, N, N′-tetramethyl-4,4′-diaminobenzophenone (Michler ketone), N, N′-tetraethyl-4,4′-diaminobenzophenone, benzyldimethyl ketal (Ciba Specialty) Chemicals, IRGACURE (Irgacure) 651), benzyl ketals such as benzyl diethyl ketal, 2,2-dimethoxy-2-phenylacetophenone, p-tert-butyldichloroacetate Enone, acetophenones such as p-dimethylaminoacetophenone, xanthones such as 2,4-dimethylthioxanthone and 2,4-diisopropylthioxanthone, or hydroxycyclohexyl phenyl ketone (manufactured by Ciba Specialty Chemicals, IRGACURE (Irgacure) 184) 1- (4-isopropylphenyl) -2-vitoxy-2-methylpropan-1-one (Merck, Darocur 1116), 2-hydroxy-2-methyl-1-phenylpropan-1-one (Merck) Manufactured, Darocur 1173) and the like, and these may be used alone or in combination of two or more.

  Examples of (C) photoinitiators that can be used as photoinitiators include 2,4,5-triallylimidazole dimer, 2-mercaptobenzoxazole, leucocrystal violet, and tris (4-diethylamino-2). Combinations with -methylphenyl) methane and the like are also mentioned. In addition, although there is no photoinitiation by itself, an additive that can be used as a sensitizer system with a better photoinitiation performance as a whole when used in combination with the above substances, such as triethanolamine for benzophenone, etc. Secondary amines can be used.

  The above is an example of an acrylic photocurable resin, but an epoxy photocurable resin that is usually used can also be preferably used as the dispersion medium resin of the wavelength conversion film of the present invention.

When a thermoplastic resin that flows by heating or pressurization is used for the dispersion medium resin of the wavelength conversion film resin composition, for example, natural rubber (refractive index (hereinafter also referred to as n) = 1.52), polyisoprene ( n = 1.521), poly-1,2-butadiene (n = 1.50), polyisobutene (n = 1.505 to 1.51), polybutene (n = 1.513), poly-2-heptyl- 1,3-butadiene (n = 1.50), poly-2-t-butyl-1,3-butadiene (n = 1.506), poly-1,3-butadiene (n = 1.515), etc. (Di) enes, polyoxyethylene (n = 1.456), polyoxypropylene (n = 1.450), polyvinyl ethyl ether (n = 1.454), polyvinyl hexyl ether (n = 1.659), Polyvinyl butyl ester Polyethers such as ter (n = 1.456), polyesters such as polyvinyl acetate (n = 1.467), polyvinyl propionate (n = 1.467), polyurethane (n = 1.5-1. 6), ethyl cellulose (n = 1.479), polyvinyl chloride (n = 1.54 to 1.55), polyacrylonitrile (n = 1.52), polymethacrylonitrile (n = 1.52), polysulfone (N = 1.633), polysulfide (n = 1.6), phenoxy resin (n = 1.5-1.6), polyethyl acrylate (n = 1.469), polybutyl acrylate (n = 1. 466), poly-2-ethylhexyl acrylate (n = 1.463), poly-t-butyl acrylate (n = 1.464), poly-3-ethoxypropyl acrylate ( = 1.465), polyoxycarbonyltetramethacrylate (n = 1.465), polymethyl acrylate (n = 1.472-1.480), polyisopropyl methacrylate (n = 1.473), polydodecyl methacrylate (n = 1.474), polytetradecyl methacrylate (n = 1.475), poly-n-propyl methacrylate (n = 1.484), poly-3,3,5-trimethylcyclohexyl methacrylate (n = 1.484) , Polyethyl methacrylate (n = 1.485), poly-2-nitro-2-methylpropyl methacrylate (n = 1.487), poly-1,1-diethylpropyl methacrylate (n = 1.490), polymethyl Poly (meth) acrylic acid ester such as methacrylate (n = 1.490) is a dispersion medium It can be used as a resin.
Two or more kinds of these thermoplastic resins may be copolymerized as required, or two or more kinds may be blended and used.

  Furthermore, as a copolymer resin with the above resin, epoxy acrylate (n = 1.48 to 1.60), urethane acrylate (n = 1.5 to 1.6), polyether acrylate (n = 1.48 to 1. 49), polyester acrylate (n = 1.48 to 1.54), etc. can also be used. In particular, urethane acrylate, epoxy acrylate, and polyether acrylate are excellent from the viewpoint of adhesiveness.

  As epoxy acrylate, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, allyl alcohol diglycidyl ether, resorcinol diglycidyl ether, adipic acid diglycidyl ester, phthalic acid diglycidyl ester, polyethylene glycol diglycidyl ether And (meth) acrylic acid adducts such as trimethylolpropane triglycidyl ether, glycerin triglycidyl ether, pentaerythritol tetraglycidyl ether, and sorbitol tetraglycidyl ether.

  A polymer having a hydroxyl group in the molecule such as epoxy acrylate is effective for improving the adhesion. These copolymer resins can be used in combination of two or more as required. The softening temperature of these resins is preferably 200 ° C. or less, and more preferably 150 ° C. or less from the viewpoint of handleability. Considering that the use environment temperature of the solar cell unit is usually 80 ° C. or lower and workability, the softening temperature of the resin is particularly preferably 80 to 120 ° C.

  The composition of the other resin composition when a thermoplastic resin is used as the dispersion medium resin is not particularly limited as long as it contains the above-described coated fluorescent substance particles, but usually used components such as a plasticizer and a flame retardant , Stabilizers and the like can be contained.

  In order to increase the refractive index of the wavelength conversion film, an inorganic material (inorganic fine particles) having a high refractive index (preferably a refractive index of 1.6 or more) can be dispersed in the resin composition for wavelength conversion film. However, if the size of the inorganic fine particles dispersed in the resin is larger than the wavelength, light is scattered, which is counterproductive.

  Examples of such inorganic fine particles include titanium oxide, zirconium oxide, zinc oxide, tin oxide, cerium oxide, antimony oxide, indium tin mixed oxide, antimony tin mixed oxide, and the like. Surface treatment may be performed with silica, zirconium oxide, higher fatty acid or the like.

  In order to disperse these inorganic fine particles in the resin, a dispersant, titanate-based, aluminum-based, or silicon-based coupling agent may be used. Dispersants include, for example, Disperbyk-111, Disperbyk-110, Disperbyk-116, Disperbyk-140, Disperbyk-161, Disperbyk-162, Disperbyk-163, products supplied under the trade name of Disperbic of Big Chemie Japan. Disperbyk-164, Disperbyk-170, Disperbyk-171, Disperbyk-174, Disperbyk-180, Disperbyk-182, etc., Kao Acetamine 24, Acetamine 86, Cotamine 24P, Cotamine 86PW, Cotamine 86PW, Cotamine 86PW Farmin 08D, Farmin 20D, Farmin 80, Farmin 86T, Farmin , Farmin T, Farmin D86, Farmin DM 24C, Farmin DM 0898, Farmin DM 1098, Farmin DM 2098, Farmin DM 2465, Farmin DM 2463, Farmin DM 2458, Farmin DM 4098, Farmin DM 4662, Farmin DM 6098, Farmin DM 6875, Farmin DM 8680, Farmin DM 8085, Farmin DM 2285, etc. Can be mentioned.

  In addition, as titanate coupling agents, products provided by Ajinomoto Co. under the trade name Plenact, KR-TTS, KR-46B, KR-55, KR-41B, KR-38S, KR-138S, KR-238S, 338X, KR-44, KR-9SA and the like. Examples of the aluminum coupling agent include Plenact AL-M manufactured by the same company.

On the other hand, when the organic-inorganic hybrid composition obtained by using the sol-gel method is used for the resin composition for wavelength conversion film, the fluorescent substance as an essential component of the organic-inorganic hybrid composition, and the following general formula (a The metal alkoxide represented by this is used.
(R ¹ ) _n M- (OR ² ) _m formula (a)

Of these, it is also preferable to use a titanium tetraalkoxide represented by the following general formula (b).
Ti- (OR) Formula ₄ (b)

Complementarily, M in the general formula (a) is selected from Zn, Zr, Al, Si, Sb, Be, Cd, Cr, Sn, Cu, Ga, Mn, Fe, Mo, V, W, Ge, and Ce. It can be a metal. R ¹ and R ^{2 in} the general formula (a) are organic groups having 1 to 10 carbon atoms, and a plurality of them are bonded to M, but they may all be the same or different. n is an integer of 0 or more, m is an integer of 1 or more, and n + m is equal to the valence of M. Moreover, R of the said general formula (b) is a C1-C10 organic group. More preferred metal alkoxides are titanium tetraalkoxides, more preferably titanium tetraisopropoxide, titanium tetra (n-butoxide) and the like.
The metal alkoxide used in the organic-inorganic hybrid composition by the sol-gel method may be one kind or plural kinds.

  The organic-inorganic hybrid composition produced by the sol-gel method used as a resin composition contains the above coated phosphor particles, polymer, monomer, and initiator as essential components, and if necessary, a solvent, an adhesion aid, and a stable An agent, a surfactant and the like can be added. Examples of the polymer include the (A) photocurable resin, the monomer includes the (B) crosslinkable monomer, and the initiator includes the (C) photoinitiator. It is done.

The wavelength conversion film of the present invention comprises (1) a fluorescent material particle coating step in which fluorescent material particles are coated with silica glass by a sol-gel reaction using silicon alkoxide to obtain coated fluorescent material particles having a coating layer;
(2) The coated phosphor material particles can be dispersed in a dispersion medium resin to produce a resin composition, and the resin composition can be used to produce a wavelength conversion film.

  When an organic-inorganic hybrid composition by a sol-gel method is used as the resin composition, the wavelength conversion film is a resin composition containing the above-described coated fluorescent substance particles for the sol-gel method in the form of a solution. Alternatively, a metal alkoxide represented by (b), water and an acid and / or an alkali catalyst are added, applied to a substrate such as PET, and the solvent is evaporated by heating to obtain a semi-cured resin composition layer. It is obtained by forming a fine uneven shape after being attached to a solar battery cell. Examples of the acid catalyst used in the sol-gel method include commonly used acid catalysts such as hydrochloric acid and organic acids. Examples of the alkali catalyst include commonly used alkali catalysts such as sodium hydroxide and organic alkali. However, depending on the reactivity of the selected metal alkoxide, water and / or acid and / or alkali catalyst may not be required. The heating temperature also depends on the reactivity of the metal alkoxide.

  In the case of a highly reactive material such as Ti, the heating temperature may be about 100 ° C. or less. In addition, when forming the semi-cured resin composition layer, it is also possible to apply it as a varnish on the solar battery cell, and then form a semi-cured resin composition layer.

  In the present invention, the (-MO-) three-dimensional structure is not necessarily required as long as a high refractive index can be realized. In particular, the three-dimensional structure of titanium oxide becomes a semiconductor so as to be used in a photocatalyst.

  However, this structure is inconvenient in terms of photodegradation, so in order to intentionally break the three-dimensional structure, it can be used in combination with another metal alkoxide, or intentionally hydrolysis and dehydration condensation should be halfway. A technique that reduces the amount of water is effective. Specifically, the amount of water used in the sol-gel method is preferably 2 mol or less with respect to 1 mol of titanium atoms.

  Even if the organic-inorganic hybrid composition by the sol-gel method is used as a resin composition, in order to produce a semi-cured resin composition layer, the resin composition containing the coated phosphor particles is made of PET or the like. The method of apply | coating to a base material and volatilizing a solvent by heating and making it into a film form is mentioned. In addition, when setting it as a film form, it is also preferable to protect on the opposite surface of a base material with separator films, such as PP. What is necessary is just to vacuum-laminate to a photovoltaic cell in order to affix a film-form semi-hardened resin composition layer to a photovoltaic cell. Or it is also possible to use the said resin composition in a varnish form directly without applying a film form, apply | coat to a photovoltaic cell directly, and dry with a solvent, and it can also be set as the semi-hardened resin composition layer. The solar cell irregularities can be completely embedded at the time of application in a varnish form.

  After forming the semi-cured resin composition layer on the solar cell, next, when forming a fine concave or convex polygonal pyramid or cone on the wavelength conversion film, the same fine concave or convex shape A mold film having a polygonal pyramid or cone is placed on a semi-cured resin composition layer, vacuum laminated, and shape transferred to a semi-cured resin composition layer to obtain a wavelength conversion film. In addition, after pasting the semi-cured resin composition layer on the solar battery cell, the substrate is not obtained by forming a fine concave or convex polygonal pyramid or cone with a mold film to obtain a wavelength conversion film. Wavelength conversion by pasting the film-like resin composition layer formed on the mold film or by directly applying the resin composition to the mold film to form a fine concave or convex polygonal pyramid or cone You may affix on a photovoltaic cell after obtaining a film.

  At this time, the wavelength conversion film may be cured after the mold film is peeled off, or the wavelength conversion film may be cured with the mold film attached. The method for curing the semi-cured wavelength conversion film may impart photocurability or thermosetting to the resin composition in advance.

<Solar cell module and manufacturing method thereof>
The present invention also covers a solar module using the wavelength conversion film or the wavelength conversion film with a mold film.
The wavelength conversion film of the present invention is used as one of the light transmissive layers of a solar cell module having a plurality of light transmissive layers and solar cells.

  By using a europium complex as the fluorescent material used in the wavelength conversion film of the present invention, a solar cell module having high power generation efficiency can be realized. The europium complex converts light in the ultraviolet region into light in the red wavelength region with high wavelength conversion efficiency, and the converted light contributes to power generation in the solar battery cell.

  One method for producing a solar cell module by forming a wavelength conversion film on a solar cell using a film-like resin composition layer, which is the wavelength conversion film of the present invention, will be described with reference to FIG. .

  As shown in FIG. 2 (a), a semi-cured state containing coated fluorescent substance particles in a semi-cured state sandwiched between a base film 304 such as PET as a base material and a separator film 306 such as PP. When the resin composition layer 305 is attached to the solar battery cell, the separator film 306 is first peeled off.

  Next, as shown in FIG. 2B, a semi-cured resin composition layer 305 containing a fluorescent material composed of a semi-cured europium complex in a solar battery cell 100 using a vacuum laminator, Attaching with the film 304 attached.

  Thereafter, as shown in FIG. 2 (c), the base film 304 is peeled off, a mold film 301 is placed on the semi-cured resin composition layer 305, and as shown in FIG. Using a vacuum laminator, fine irregularities are transferred to obtain the wavelength conversion film 300a (before curing).

  After obtaining the wavelength conversion film 300a before curing, the wavelength conversion film 300a containing a fluorescent material composed of a europium complex that is semi-cured by light or heat is further cured to obtain the wavelength conversion film 300b (after curing). After curing, the mold film 301 may be left as it is, and may be sandwiched between the protective glass 201, the sealing material 202, and the back film 204 to form a module.

  Further, as shown in FIG. 2 (e), after the mold film 301 is peeled off from the state of (d), it is sandwiched between the protective glass 201, the sealing material 202 and the back film 204 as shown in FIG. Also good.

  At this time, if the texture structure of the solar battery cell is 10 μm deep and the depth of the unevenness of the mold film is 10 μm, the wavelength conversion film before lamination needs to have a thickness of at least 20 μm. In other words, the former is a pedestal portion, and the latter is a convex or concave polygonal pyramid or conical portion that is a feature of the present invention.

A mold film (a mold film serving as a template for forming a convex or concave polygonal pyramid or conical portion of a wavelength conversion film) can be produced by the method described in JP-A-2002-225133. As for the resin composition used for mold film formation, what contains the photocurable resin used with a wavelength conversion film is mentioned. The shape of the mold film is such that a large number of fine convex or concave polygonal cones or cones are spread on the light receiving surface without any gaps on the wavelength conversion film.
Specific production examples of the mold film will be described later in Examples.

  The wavelength conversion film of the present invention is a film in a state before being made into a solar module, specifically, a semi-cured film when a curable resin is used. In addition, the refractive index of the wavelength conversion film of a semi-hardened state and the wavelength conversion film after hardening (after making into a solar module) does not change a lot.

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

<Preparation of coated phosphor particles>
(Preparation of coated phosphor particles A to H)
First, phosphor particles are synthesized. 200 mg of 4,4,4-trifluoro-1- (thienyl) -1,3-butanedione (TTA) was dissolved in 7 ml of ethanol, and 1.1 ml of 1M sodium hydroxide was added thereto and mixed. 62 mg of 1,10-phenanthroline dissolved in 7 ml of ethanol is added to the above mixed solution and stirred for 1 hour, and then a 3.5 ml aqueous solution of 103 mg of EuCl ₃ · 6H ₂ O is added to obtain a precipitate. This is filtered off, washed with ethanol and dried. Recrystallization purification was performed with hexane-ethyl acetate to obtain fluorescent substance particles Eu (TTA) ₃ Phen. The primary particle diameter of the fluorescent substance particles was 10 to 50 nm.

Using the Eu (TTA) ₃ Phen obtained as described above, a sol-gel solution was prepared with the blending amounts shown in Table 1. Here, the numbers described in Table 1 indicate molar ratios. Incidentally, Eu _(TTA) 3 The amount of Phen in molar ratio is 1/160 mol with respect to TEOS. TEOS represents tetraethoxysilane, DMF represents dimethylformamide, and NH ₃ represents ammonia.

The phosphor particles (Europium complex (Eu (TTA) ₃ phen)) (primary particle size: 10 to 50 nm) obtained above were mixed in the solution prepared at the ratio described in Table 1, and stirred for 10 minutes. Went. Next, it apply | coated with the casting method on the glass substrate, and it heat-processed on 120 degreeC and the conditions for 1 hour, and produced the covering fluorescent substance particle AH.

The shape of the obtained coated phosphor particles (particles in which the periphery of Eu (TTA) ₃ phen phosphor particles was covered with silica glass) was observed with an electron microscope, and the primary particle diameter was measured. The results are shown in Table 1.

(Preparation of coated phosphor particles I to L)
A sol-gel solution was prepared with the blending amounts shown in Table 2. Here, the numbers described in Table 2 indicate the molar ratio. TEOS represents tetraethoxysilane, THF represents tetrahydrofuran, and NH ₃ represents ammonia.

The phosphor particles (Europium complex (Eu (TTA) ₃ phen)) (primary particle size: 10 to 50 nm) obtained above were mixed in the solution prepared at the ratio described in Table 2, and stirred for 10 minutes. Went. Next, it apply | coated with the casting method on the glass substrate, and it heat-processed on 120 degreeC and the conditions for 1 hour, and produced the coating fluorescent substance particle I-N.

The shape of the obtained coated phosphor particles (Eu (TTA) ₃ phen phosphor particles covered with silica glass) was observed with a scanning electron microscope, and the primary particle diameter was measured. The results are also shown in Table 2.

Example 1
<Production of solar cell module>
The manufacturing method of the solar cell module is formed by several steps. Hereinafter, a method for producing a solar cell module including a method for forming (attaching) a wavelength conversion film will be described.

(1) Preparation of photosensitive resin composition for mold film 50 parts by mass of acrylic acrylate (manufactured by Hitachi Chemical Co., Ltd., trade name: Hitaroid HA7885) as a dispersion medium resin (component A), crosslinkable monomer (component B) ) EO-modified bisphenol A dimethacrylate (manufactured by Hitachi Chemical Co., Ltd., trade name: funcryl FA-321M) and 1-hydroxy-cyclohexyl-phenylketone (Ciba) as a photoinitiator (component C) -3.0 parts by mass of Specialty Chemicals, trade name: IRGACURE 184) was dissolved in methyl ethyl ketone as an organic solvent to obtain a varnish (resin composition). A film of this varnish was formed on a silicon wafer so as to be about 5000 mm.

(2) Production of a mold film One to two drops of the resin composition is dropped onto a mold having an effective area of 155 mm square and a square pyramid having a base of 20 μm and a height of 10 μm without gap, and 50 μm A polyethylene terephthalate (PET) film (manufactured by Toyobo Co., Ltd., trade name: A-4300) subjected to a thick double-sided easy adhesion treatment was placed thereon. Air bubbles were removed with a roller so that air bubbles did not enter between the resin composition and the PET film, and UV light was irradiated from the PET side. By removing the PET film from the mold, a concave quadrangular pyramid film was obtained. The refractive index was 1.49 for both the base material and the photosensitive resin composition layer.
The square die size of the obtained mold film is the same as that of the mold.

(3) Preparation of Resin Composition Containing Coated Fluorescent Material Particles for Wavelength Conversion Film 66.67 parts by mass of toluene are added to 100 parts by mass of an epoxy resin (trade name: Ogsol EG) manufactured by Osaka Gas Chemical Co., Ltd. Stir day and night. This was used as a test resin (however, this resin alone is not cured. In this example, as a dispersion medium resin, the curability was ignored). Further, 0.3 parts by mass of the coated fluorescent material particles N synthesized above was added to make a resin composition 1.

(4) Production of wavelength conversion film On the mold film (photosensitive resin composition layer) obtained above, the resin composition 1 is applied with an applicator having a gap of 7 mil, and hot air convection drying at 100 ° C. And then dried for 15 minutes to obtain a wavelength conversion film 1. On the coating film, a semi-cured wavelength conversion film was protected with a PP film as a separator film. In addition, the wavelength conversion film 1 was formed with a square pyramid having a base of 20 μm and a height of 10 μm without any gaps, and the thickness of the pedestal portion was 42 μm.

(5) Fabrication of wavelength conversion film-attached solar cell module On solar cells that are connected to the tab line and have previously measured solar cell characteristics, the separator film is peeled off from the wavelength conversion film 1 and then placed as protective glass. Reinforced glass (Asahi Glass Co., Ltd.), EVA resin (made by Mitsui Fabro Co., Ltd., trade name: Soraeva) as a sealing material, solar cell with a wavelength conversion film attached (light receiving surface facing down), A PET film (product name: A-4300, manufactured by Toyobo Co., Ltd.) was stacked as the EVA resin and the back film, and laminated using a vacuum laminator to obtain a solar cell module 1 with a wavelength conversion film. The measurement of the solar cell characteristics is the same for the solar cell module characteristic evaluation, apparatus, and method described below.
The refractive index of each layer is as follows. Protective glass (1.50), sealing material (1.49), mold film substrate part (PET) (1.49), mold film fine uneven part (1.49), wavelength conversion film 1 (1.61) ), SiNx: H layer (2.1), Si layer (3.4) among solar cells.
Table 3 shows the refractive index and layer thickness of each layer.

(6) Characteristics of solar cell module Wacom Denso Co., Ltd., solar simulator, WXS-155S-10, AM1.5G, Eihiro Seiki Co., Ltd., IV curve tracer, MP-160, wavelength conversion film The performance of the attached solar cell module 1 was evaluated. The evaluation data is shown in Table 4.

(Example 2)
<Production of solar cell module>
A solar cell module provided with a wavelength conversion film not including a fine shape was produced.
(1) Preparation of resin composition containing coated fluorescent substance particles for wavelength conversion film To 100 parts by mass of methyl methacrylate polymer (manufactured by Wako Pure Chemical Industries, Ltd.), 163 parts by mass of toluene was added and stirred for several days to form a solution. . To this resin solution, 0.3 parts by mass of the coated fluorescent substance particles A synthesized as described above was further added to obtain a resin composition 2.

(2) Production of wavelength conversion film The resin composition 2 obtained above is dropped onto a solar cell that is connected to a tab line and whose solar cell characteristics are measured in advance, and the thickness of the tab line is obtained by an applicator. Was applied as a gap. It dried over 15 minutes with the 100 degreeC hot-air convection type dryer, produced the wavelength conversion film, and obtained the photovoltaic cell with a wavelength conversion film.
(3) Production of solar cell module with wavelength conversion film Tempered glass (manufactured by Asahi Glass Co., Ltd.) as protective glass, EVA resin (manufactured by Mitsui Fabro Co., Ltd., trade name: Soraeva) as sealing material, obtained above A laminated solar cell with a layer containing coated phosphor particles, (with the light-receiving surface facing down), the EVA resin, and a PET film (trade name: A-4300, manufactured by Toyobo Co., Ltd.) as a back film, a vacuum laminator Was used to obtain a solar cell module 2 with a wavelength conversion film.
The refractive index of each layer is as follows. Among the protective glass (1.50), the sealing material (1.49), the wavelength conversion film 2 (1.49), and the solar battery cell, SiNx: H layer (2.1), Si layer (3.4).
Table 3 shows the refractive index and layer thickness of each layer.
(4) Solar cell module characteristics The solar cell module 2 was evaluated in the same manner as in Example 1. The data is shown in Table 4.

(Comparative Example 1)
<Production of solar cell module>
A solar cell module having no wavelength conversion film was produced by the following method.
(1) Production of solar cell module Reinforced glass (manufactured by Asahi Glass Co., Ltd.) as protective glass, EVA resin (manufactured by Mitsui Fabro Co., Ltd., trade name: Soraeva) as the sealing material, and the coated fluorescence obtained above Solar cell with a layer containing substance particles (with light-receiving surface facing down), EVA resin, PET film (trade name: A-4300, manufactured by Toyobo Co., Ltd.) as a back film, and lamination using a vacuum laminator As a result, a solar cell module 3 was obtained.
The refractive index of each layer is as follows. Among the protective glass (1.50), the sealing material (1.49), and the solar battery cell, SiNx: H layer (2.1), Si layer (3.4).
Table 3 shows the refractive index and layer thickness of each layer.
(2) Solar cell module characteristics The solar cell module 3 was evaluated in the same manner as in Example 1. The data is shown in Table 4.

  The wavelength conversion film of the present invention can reduce sunlight loss due to spectrum mismatch and have a higher visible light transmittance, thereby improving light utilization efficiency and improving power generation efficiency.

100 solar cell 201 protective glass (cover glass)
202 Sealing material (filler)
203 Tab wire 204 Back film 300a, b Wavelength conversion film 301 Type film 304 Base film 305 Semi-cured resin composition layer 306 Separator film

Claims (7)

In a wavelength conversion film containing a fluorescent substance and a dispersion medium resin, which is used as one of the light transmissive layers of a solar battery module having a plurality of light transmissive layers and solar cells,
The wavelength conversion film, wherein the fluorescent substance is a coated fluorescent substance particle having a fluorescent substance particle and a coating layer covering the periphery of the fluorescent substance particle. The wavelength conversion film is disposed on a light receiving surface of the solar battery cell, the coating layer has a refractive index of 1.5 to 2.1, and the dispersion medium resin has a refractive index of 1.5 to 2.1. And
When the plurality of light transmissive layers are layer 1, layer 2,..., Layer m from the light incident side, and the refractive indexes thereof are n1, n2,. The wavelength conversion film according to claim 1, wherein ≦.   The wavelength conversion film according to claim 1, wherein the coating layer is silica glass formed by a sol-gel method.   The wavelength conversion film according to any one of claims 1 to 3, wherein the fluorescent substance is a europium complex.   The solar cell module which has a wavelength conversion film as described in any one of Claims 1-4. A phosphor particle coating step of coating phosphor particles with silica glass by a sol-gel reaction using silicon alkoxide to obtain coated phosphor particles having a coating layer;
The said fluorescent substance particle is disperse | distributed to dispersion medium resin, a resin composition is produced, and it has a film formation process which forms a wavelength conversion film using this resin composition. The manufacturing method of the wavelength conversion film as described in a term.   In the manufacturing method of the solar cell module which has a some light transmissive layer and a photovoltaic cell, the wavelength conversion film as described in any one of Claims 1-4 is laminated | stacked, and one of the said light transmissive layers The manufacturing method of the solar cell module characterized by having the process of comprising.

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