JP2018180159A - Wavelength conversion filter and solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wavelength conversion filter capable of enhancing the durability by suppressing decomposition of phosphor even when using a phosphor having a high solubility in water, and a solar cell module.SOLUTION: A wavelength conversion filter 10 includes: an inorganic phosphor 11 having a solubility in water of 0.1 or more and a host crystal being a fluorophosphate; and a transparent resin 12 having a water absorption of 0.1% or less and dispersing inorganic phosphor. A solar cell module 100 includes: a photoelectric conversion cell; a surface protection material 30 for protecting the side of the photoelectric conversion cell, on which light incidents; and a wavelength conversion filter formed between the photoelectric conversion cell and the surface protection material.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a wavelength conversion filter and a solar cell module. In particular, the present invention relates to a wavelength conversion filter with improved durability and a solar cell module using the wavelength conversion filter.

  Photovoltaic power generation, which converts sunlight into electrical energy, is a clean, renewable energy. However, since only light of a certain wavelength in sunlight is used for photoelectric conversion, it is a factor of a decrease in photoelectric conversion efficiency.

  Specifically, in a solar battery cell that converts sunlight into electrical energy, the photoelectric conversion efficiency of ultraviolet light is lower than the photoelectric conversion efficiency of visible light. For example, in a solar battery cell, the ultraviolet light in the wavelength range of 300 to 400 nm has low photoelectric conversion efficiency, and the visible light and infrared light in the wavelength range of 400 to 1200 nm have high photoelectric conversion efficiency. Also, ultraviolet light within the wavelength range of less than 380 nm is likely to damage the solar cell. For this reason, in the conventional solar cell, the ultraviolet light was cut by the filter.

  However, if ultraviolet light within the wavelength range of less than 380 nm can be used for power generation, improvement of the photoelectric conversion efficiency of the solar battery cell can be expected. For this reason, in recent years, in solar cells, it has been studied to convert ultraviolet light into light of a long wavelength and use it for power generation, instead of simply cutting ultraviolet light. Specifically, a technique for providing a wavelength conversion filter for converting ultraviolet light into visible light or infrared light has been considered.

As such a technology, for example, a semiconductor light emitting device described in Patent Document 1 is disclosed. In Patent Document 1, a phosphor that absorbs at least a part of light from a light source and emits light having a wavelength different from that of the light from the light source, and a semiconductor light emitting element formed on a substrate having conductivity as a light source Discloses a semiconductor light emitting device comprising: And as a fluorescent substance, the solubility in 100 g of water at 20 ° C. is 0.005 g or more and 7 g or less, and a fluorine complex fluorescent substance activated with Mn ⁴⁺ is used.

JP, 2010-232381, A

  However, when a phosphor having high solubility in water is used for a wavelength conversion filter, the phosphor may be decomposed by moisture in the air, and the wavelength conversion efficiency of the phosphor may be reduced. Therefore, in order to suppress the decomposition of the phosphor, a technique of applying a coating having a gas barrier property to the surface of the wavelength conversion filter has been studied. However, when manufacturing the said wavelength conversion filter, since the process of providing a gas-barrier coating is needed, there existed a problem that a manufacturing process and cost increased.

  The present invention has been made in view of the problems of the prior art. And the object of the present invention is a wavelength conversion filter capable of suppressing the decomposition of the phosphor and improving the durability even when using a phosphor having high water solubility, and a solar using the wavelength conversion filter It is in providing a battery module.

  In order to solve the above-mentioned subject, the wavelength conversion filter concerning the first mode of the present invention is the inorganic fluorescent substance whose solubility in water is 0.1 or more, and whose host crystal is fluorophosphate. The transparent resin has a water absorption of 0.1% or less and disperses the inorganic phosphor.

  The solar cell module according to the second aspect of the present invention is provided between a photoelectric conversion cell, a surface protection material that protects the light incident side to the photoelectric conversion cell, and the photoelectric conversion cell and the surface protection material. And a wavelength conversion filter.

  According to the present invention, a wavelength conversion filter capable of suppressing the decomposition of the phosphor and enhancing the durability even when the phosphor having high water solubility is used, and a solar cell module using the wavelength conversion filter It is possible to provide

It is the schematic for demonstrating the mechanism in which inorganic fluorescent substance decomposes | disassembles by water | moisture content. The wavelength conversion filter which concerns on embodiment of this invention WHEREIN: It is the schematic which shows the state which water | moisture content does not easily retain in transparent resin. In the conventional wavelength conversion filter, it is the schematic which shows the state which water tends to retain in transparent resin. It is a sectional view showing typically an example of a solar cell module concerning an embodiment of the present invention. It is a graph which shows the relationship of an internal quantum efficiency maintenance factor and elapsed time when the moisture resistance in the wavelength conversion filter of an Example and a comparative example is evaluated. It is a graph which shows the emission spectrum and excitation spectrum in the inorganic fluorescent substance of a reference example 1 and a reference comparative example. It is a graph which shows the emission spectrum and excitation spectrum in the inorganic fluorescent substance of the reference example 2. FIG. It is a graph which shows the emission spectrum and excitation spectrum in the inorganic fluorescent substance of the reference example 3. FIG. It is a graph which shows the emission spectrum and excitation spectrum in the inorganic fluorescent substance of the reference example 4. FIG. It is a graph which shows the relationship of the internal quantum efficiency maintenance factor and temperature in the inorganic fluorescent substance of a reference example 1 and a reference comparative example. It is a graph which shows the relationship of the internal quantum efficiency maintenance factor and temperature in the inorganic fluorescent substance of the reference example 4. FIG.

  Hereinafter, the wavelength conversion filter which concerns on this embodiment, and the solar cell module using the said wavelength conversion filter are demonstrated in detail. The dimensional ratios in the drawings are exaggerated for the convenience of description, and may differ from the actual ratios.

[Wavelength conversion filter]
The wavelength conversion filter of the present embodiment has a function of, for example, absorbing ultraviolet light in sunlight and converting it into visible light. As described above, the solar battery cell has low photoelectric conversion efficiency for ultraviolet light in the wavelength range of 300 nm to less than 400 nm, and photoelectric conversion efficiency in the visible light and infrared light region in the wavelength range of 400 nm to less than 1200 nm. Is high. Therefore, by converting ultraviolet light into visible light or infrared light using a wavelength conversion filter, visible light or infrared light with high spectral sensitivity is increased, so that the photoelectric conversion efficiency of the solar cell can be improved. It becomes.

  However, when the solubility of the inorganic fluorescent substance contained in the wavelength conversion filter is high, the inorganic fluorescent substance may be gradually decomposed by moisture in the air, and the wavelength conversion efficiency may be lowered. That is, as shown in FIG. 1, when the inorganic phosphor and water are brought into contact and hydrated, in the case of an inorganic phosphor having high solubility in water, the cations and anions constituting the phosphor are hydrated ions. It combines with and separates. As a result, the crystal structure of the inorganic phosphor may be broken and the wavelength conversion efficiency may be reduced.

  In order to suppress such decomposition of the inorganic phosphor by moisture in the air, the wavelength conversion filter of the present embodiment has a water absorption coefficient of 0.1% or less and a transparent resin for dispersing the inorganic phosphor. Have. By using a transparent resin having a low water absorption as the light transmitting material for dispersing the inorganic fluorescent substance, the contact ratio between the inorganic fluorescent substance and water decreases, so that the decomposition of the inorganic fluorescent substance can be suppressed. .

  Specifically, as shown in FIG. 2, when the inorganic phosphor 11 is dispersed inside the transparent resin 12 with low water absorption, the concentration of water around the inorganic phosphor 11 is low. Further, even if water molecules intrude into such transparent resin 12, the water molecules are immediately discharged to the outside of the transparent resin 12 because the affinity between the transparent resin 12 and the water molecules is low. Therefore, the contact ratio between the inorganic phosphor 11 and the water molecules is reduced, and the decomposition of the inorganic phosphor can be suppressed. Moreover, even if the inorganic fluorescent substance 11 and a water molecule contact, since these contact time is short, decomposition | disassembly of the inorganic fluorescent substance 11 does not advance easily. As described above, by combining the inorganic phosphor 11 and the transparent resin 12 having a low water absorption rate, the water concentration around the inorganic phosphor 11 can be reduced, and the dissolution rate of the inorganic phosphor 11 can be delayed. As a result, it is possible to improve the durability of the inorganic phosphor 11 in the wavelength conversion filter.

  On the other hand, when a transparent resin having high water absorbability is used as the translucent material for dispersing the inorganic fluorescent substance, as shown in FIG. 3, water molecules stay inside the transparent resin 12a, and therefore inorganic The concentration of water around the phosphor 11 is high. As a result, hydration of the inorganic fluorescent substance 11 progresses and the crystal structure of the inorganic fluorescent substance is broken, so that the durability of the inorganic fluorescent substance 11 is lowered.

  As described above, in the wavelength conversion filter of the present embodiment, the dissolution rate of the inorganic phosphor 11 is delayed by using the transparent resin 12 having a water absorption of 0.1% or less, and the durability of the inorganic phosphor 11 is effective. Be able to The transparent resin 12 having such a water absorption rate of 0.1% or less is not particularly limited, but at least one selected from the group consisting of polyolefin, alicyclic polyolefin, ethylene acrylic acid ester copolymer and silicone resin is used. be able to. Although these resins have a low water absorption rate, they can be suitably used as the transparent resin 12 because they have a high transmittance of ultraviolet light, visible light and infrared light.

  Moreover, since the wavelength conversion filter of this embodiment is used for the solar cell module used outdoors, weather resistance is requested | required. However, since the above-mentioned resin has high durability for a long time, it is possible to further improve the weather resistance of the wavelength conversion filter. In the present specification, the water absorption rate of the transparent resin 12 can be measured based on method A of Japanese Industrial Standard JIS K 7209 (Plastics-How to Determine Water Absorption Rate).

  As described above, the water absorption rate of the transparent resin 12 is preferably 0.1% or less, but the water absorption rate is more preferably 0.05% or less, and particularly preferably 0.03% or less . As the water absorption rate of the transparent resin 12 decreases, the contact ratio between the inorganic phosphor 11 and water decreases, and the dissolution rate of the inorganic phosphor 11 decreases, so that the durability of the inorganic phosphor 11 can be further enhanced. Become.

  The wavelength conversion filter of the present embodiment contains an inorganic phosphor 11 capable of converting ultraviolet light into visible light or infrared light. Preferably, the inorganic phosphor 11 according to the present embodiment has a solubility in water of 0.1 or more, and the host crystal is a fluorophosphate. As described above, since the wavelength conversion filter of the present embodiment uses the transparent resin 12 having a low water absorption, the long-term durability of the inorganic phosphor is improved even when the inorganic phosphor having a high water solubility is used. It is possible to maintain the wavelength conversion efficiency in a high state. The solubility of the inorganic phosphor 11 refers to the mass (g) of the inorganic phosphor dissolved in 100 g of water at room temperature (25 ° C. ± 1).

  In the inorganic phosphor 11 according to the present embodiment, the host crystal is preferably a fluorophosphate. Moreover, it is also preferable that the inorganic fluorescent substance 11 is a fluorophosphate containing a base crystal containing an alkali metal element. An inorganic phosphor using such a fluorophosphate has high emission intensity even at high temperatures, and tends to have high quantum efficiency. Therefore, it becomes possible to use suitably for the wavelength conversion filter for solar cell modules. Moreover, the fluorophosphate containing an alkali metal element tends to have high solubility in water. However, as described above, since the transparent resin 12 in the present embodiment has a low water absorption rate, it is possible to improve the durability even when using a host crystal with high solubility.

In the inorganic phosphor 11 according to the present embodiment, at least one of the constituent elements of the compound represented by the general formula (1) is at least one of a trivalent cerium ion (Ce ³⁺ ) and a divalent europium ion (Eu ²⁺ ) More preferably, it is a substituted phosphor.
A ₂ MPO ₄ X (1)
In the formula, A is an alkali metal element and contains at least Na, M is an element selected from the group consisting of Mg, Ca, Sr, Ba and Zn, contains at least Mg, and X is a halogen element And at least F. The alkali metal element can be at least one selected from the group consisting of lithium (Li), sodium (Na), potassium (K), rubidium (Rb) and cesium (Cs). The halogen element can be at least one selected from the group consisting of fluorine (F), chlorine (Cl), bromine (Br) and iodine (I).

  When the inorganic phosphor 11 according to the present embodiment uses a compound represented by the general formula (1) and the crystal structure is a Moraskoite structure, a phosphor having excellent temperature characteristics while converting ultraviolet light into visible light can do. In addition, by adjusting the constituent elements, it is possible to control the shapes and peak positions of the excitation spectrum and the fluorescence spectrum.

In the compound represented by the general formula (1), the element to be substituted by Ce ³⁺ and Eu ²⁺ which are emission centers is preferably M. This is because, among the cationic elements A, M and P that can be substituted by Ce ³⁺ and Eu ²⁺ , the valence of M is most similar to the valence of Ce ³⁺ and Eu ²⁺ .

Further, in the compound represented by the general formula (1), it is also preferable that the element substituted by Ce ³⁺ and Eu ²⁺ which are emission centers is A. This is among the cationic element A, M and P ^{of Ce 3+} and ^{Eu 2+} can be substituted, because the ionic radius of A is the most approximate to the ionic radius of ^{Ce 3+} and ^{Eu 2+.}

Inorganic phosphor 11 according to the present _embodiment, Na 2 MgPO ₄ part of F of the constituent elements is more preferably a phosphor which is substituted by at least one of ^{Ce 3+} and ^{Eu 2+.} That is, it is preferable that the matrix of the inorganic fluorescent substance of the present embodiment is Na ₂ MgPO ₄ F which is an acid halide, and the luminescent center be at least one of Ce ³⁺ and Eu ²⁺ . It is preferable to use Na ₂ MgPO ₄ F, which is a mineral called Moraskoite, as the matrix of the inorganic fluorescent substance, because the luminous intensity is high and the quantum efficiency tends to be high even when the temperature of the fluorescent substance becomes high.

As mentioned above, it is preferable that the inorganic fluorescent substance 11 which concerns on this embodiment makes at least one of a cerium ion (Ce <^3+> ) and a europium ion (Eu <^2+> ) a luminescence center. Ce ³⁺ and ^{Eu 2+} takes the mechanism of 4f _n ⇔4f _n-1 5d 1 acceptable light absorption and emission based on the transition. Therefore, the wavelengths of absorption and emission change depending on the host crystal in which they are activated. Therefore, light in the near-ultraviolet to violet region can be converted to visible light by selecting Ce ³⁺ or Eu ²⁺ as the emission center and selecting a suitable host crystal. In the above 4 f _n ⇔ 4 f _{n − 15} d ₁ permissible transition, Ce ³⁺ corresponds to n = 1 and Eu ²⁺ corresponds to n = 7.

In general, in a phosphor having Ce ³⁺ or Eu ²⁺ as the emission center, the excitation spectrum and the emission spectrum largely change depending on the type of host crystal. Therefore, the type of host crystal can be designed according to the application, and an appropriate phosphor can be selected. In addition, by adjusting the composition of the host crystal in the range in which the crystal structure does not collapse, it is possible to control the peak position of the excitation spectrum and the emission spectrum.

In addition, the shape of the excitation spectrum of the phosphor having Ce ³⁺ or Eu ²⁺ as the emission center is not a sharp shape in the form of a line spectrum, but a wide shape. Therefore, it can be used in combination with excitation light sources of various emission wavelengths.

Here, as a general inorganic phosphor, one using a rare earth ion other than Ce ³⁺ and Eu ²⁺ as an emission center is also known. However, if the emission center is a rare earth ion other than Ce ³⁺ and Eu ²⁺ , it is difficult to obtain an inorganic phosphor that absorbs ultraviolet light with a wavelength of 300 to 400 nm even if the composition of the host crystal is adjusted. However, when at least one of Ce ³⁺ and Eu ²⁺ is contained, it is possible to obtain an inorganic phosphor that absorbs ultraviolet light having a wavelength of 300 to 400 nm by adjusting the composition of the host crystal. The main reasons are as follows.

  Among the rare earth ions, the rare earth ions from Ce to Yb have electrons in the 4f orbital. There are two types of absorption and emission of light derived from rare earth ions: those due to the transition in the 4f shell and those due to the transition between the 5d shell and the 4f shell.

Among rare earth ions, ^ions other than Ce ³⁺ and Eu ²⁺ generally absorb and emit light by transition in the 4f shell. However, in the transition in the 4f shell, since the electrons in the 4f orbital are inside the electrons in the 5s orbital and the 5p orbital and shielded, fluctuation of the energy level due to the influence of the surroundings hardly occurs. For this reason, in the inorganic fluorescent substance which uses ions other than Ce ³⁺ and Eu ²⁺ as the emission center, the change of the emission wavelength is small even if the composition of the host crystal is adjusted It is difficult to get

In contrast, Ce ³⁺ and Eu ²⁺ absorb and emit light by the transition between the 5d and 4f shells, ie, the transition between 4f ⁿ and 4f ^{n −} 15d. In the transition between the 5d shell and the 4f shell, since the 5d orbital is not shielded from other orbitals, fluctuation of the energy level of the 5d orbital due to the influence of the surroundings is likely to occur. Therefore, in the case of an inorganic phosphor having Ce ³⁺ and Eu ²⁺ as emission centers, the emission wavelength can be adjusted by adjusting the composition of the host crystal in the case of light emission based on the transition from the 4f ^n- 15d ¹ level to the 4f orbit. It is possible to make a big change. This large change in emission wavelength makes it possible to absorb ultraviolet light with a wavelength of 300 to 400 nm in an inorganic phosphor having Ce ³⁺ and Eu ²⁺ as emission centers.

Here, the compound Na ₂ MgPO ₄ F can form a solid solution by forming a solid solution with a compound different from the Na ₂ MgPO ₄ F. Therefore, the phosphor of the present embodiment may be composed of a solid solution having Na ₂ MgPO ₄ F as an end component. The solid solution preferably has the same crystal structure as Na ₂ MgPO ₄ F, and a part of the constituent elements of the solid solution is preferably replaced with at least one of Ce ³⁺ and Eu ²⁺ . In addition, although "the same crystal structure" changes a crystal | crystallization parameter by making another element dissolve, it means that the arrangement | sequence order of atoms is the same. _Thus, Na 2 MgPO ₄ F using a solid solution of the end component, that further the same crystal structure as _Na 2 MgPO _{4 F,} excitation spectrum and emission spectrum of the phosphor of the Na 2 MgPO ₄ F as a host It is possible to control the shape and position of

Note that a compound containing Li, K, Rb, Cs having the same valence as Na or an element such as Ca, Sr, Ba, Zn having the same valence as Mg tends to form a solid solution with Na ₂ MgPO ₄ F. Therefore, it is also preferable that the solid solution according to the present embodiment contains at least one element selected from the group consisting of Li, K, Rb, Cs, Ca, Sr, Ba and Zn.

In the inorganic phosphor 11 of the present embodiment, when the valence of the element to be replaced with Ce ³⁺ and Eu ²⁺ in the parent compound, and the valence of Ce ³⁺ and Eu ²⁺ different, simultaneously replacing the other elements in the matrix compound It is preferable to perform charge compensation to compensate for the charge deviation. For example, in the case where Ce ³⁺ and Eu ²⁺ replace a small-valence element in the host compound, part of the M element may be substituted with an alkali metal element, and part of phosphorus is substituted with silicon. May be

As described above, the inorganic phosphor 11 may contain an alkali metal element. This makes it possible to control the excitation spectrum and the emission spectrum derived from Eu ²⁺ or Ce ³⁺ . The alkali metal element is preferably at least one element selected from the group consisting of lithium (Li), sodium (Na), potassium (K), rubidium (Rb) and cesium (Cs).

Moreover, the inorganic fluorescent substance 11 may contain halogen elements other than a fluorine in the range which does not impair the crystal structure of the said fluorescent substance. This makes it possible to control the excitation spectrum and emission spectrum derived from Eu ²⁺ or Ce ³⁺ and the refractive index of the phosphor. The halogen element is preferably at least one element selected from the group consisting of chlorine (Cl), bromine (Br) and iodine (I).

The inorganic phosphor 11 may further contain manganese (Mn). In particular, the phosphor may further contain manganese ions (Mn ²⁺ ). As a result, energy transfer from Eu ²⁺ or Ce ³⁺ to Mn ²⁺ occurs, and it becomes possible to emit light on the long wavelength side by causing Mn ^{2+ to} be a luminescent center.

  The inorganic phosphor 11 preferably has a refractive index of 1.47 or more and less than 1.53. As a result, the inorganic phosphor 11 has a refractive index similar to that of the transparent resin 12. Therefore, when the inorganic fluorescent substance 11 is dispersed in the transparent resin 12, the inorganic fluorescent substance 11 can be complexed with the transparent resin 12 to obtain a transparent wavelength conversion filter.

  The inorganic fluorescent substance 11 preferably has a light emission peak wavelength of 400 nm or more and less than 500 nm when excited by ultraviolet light having a wavelength of 350 nm. Thereby, it becomes a fluorescent substance which can convert the ultraviolet rays contained in sunlight into visible light, and it is possible to obtain a wavelength conversion filter which can improve the output of the solar cell module.

  When the internal quantum efficiency measured at 30 ° C. is 100%, the inorganic phosphor 11 of the present embodiment preferably has an internal quantum efficiency of 90% or more measured at 150 ° C. The inorganic phosphor 11 hardly reduces the internal quantum efficiency even in a high temperature environment of 150 ° C., and exhibits high internal quantum efficiency. Therefore, it can be used for an electronic device used in a high temperature environment or an electronic device which is likely to have a high temperature due to a high output. Moreover, when the inorganic fluorescent substance 11 is used for a solar cell module, it becomes possible to absorb an ultraviolet light sufficiently even at the time of summer high temperature, to carry out wavelength conversion, and to improve the output of a solar cell module.

The inorganic phosphor 11 preferably has a center particle diameter (D ₅₀ ) of 0.1 μm or more and less than 100 μm, and more preferably 0.3 μm or more and less than 30 μm. When the central particle size of the inorganic phosphor is in this range, it is possible to obtain an inorganic phosphor and a wavelength conversion filter excellent in the absorptivity of excitation light and the quantum efficiency. The central particle size of the inorganic fluorescent substance can be measured, for example, by a laser diffraction scattering type particle size distribution measuring apparatus.

  Moreover, it is preferable that the average particle diameter of the inorganic fluorescent substance 11 is 0.1 micrometer or more and less than 100 micrometers, and it is more preferable that it is 0.3 micrometers or more and less than 30 micrometers. Also when the average particle diameter of the inorganic phosphor is in this range, it is possible to obtain a phosphor and a wavelength conversion filter excellent in the absorptivity of excitation light and the quantum efficiency. In addition, the average particle diameter of inorganic fluorescent substance is defined as the average value of the longest axis length in arbitrary 20 or more fluorescent substance particle | grains observed with the scanning electron microscope.

  The inorganic fluorescent substance 11 of this embodiment can be manufactured by a well-known method, and can be synthesize | combined using an orthodox solid phase reaction.

  Specifically, first, raw material powders such as oxides, fluorides and ammonium salts are prepared. Next, the raw material powder is prepared so as to have a stoichiometric composition of the desired compound or a composition close to this, and thoroughly mixed using a mortar, a ball mill, a stirrer or the like. The mixing method may be dry mixing or wet mixing, as long as sufficient mixing is performed. In the case of wet mixing, ion-exchanged water, ethanol, isopropyl alcohol, acetone or the like can be used as a medium, but other mediums may be used without limitation.

Then, the inorganic phosphor 11 of the present embodiment can be prepared by firing the mixed material in an electric furnace or the like using a firing vessel such as an alumina crucible, a platinum crucible, or a magnetic crucible. In addition, when baking mixed raw material, it is preferable to heat for several hours in air | atmosphere or reducing atmosphere at the calcination temperature of 700-1000 degreeC. In particular, baking in a reducing atmosphere is preferable because it is easy to reduce Ce or Eu to a state of Ce ³⁺ or Eu ²⁺ and to easily synthesize an inorganic phosphor with high efficiency. Note that the reducing atmosphere is preferably an atmosphere of nitrogen, argon, a mixed gas of nitrogen and hydrogen, a mixed gas of argon and nitrogen, ammonia, carbon monoxide and the like.

Further, an additive such as flux may be added to the raw material of the inorganic phosphor. As an additive, in order to suppress volatilization of an alkali metal element or fluorine, a compound of an alkali metal element or ammonium fluoride is preferable. As the flux, for example, chlorides such as NH ₄ Cl, LiCl, NaCl, KCl, RbCl, CsCl, CaCl ₂ , SrCl ₂ , ZnCl ₂ , MgCl ₂ and their hydrated salts; LiF, NaF, KF, RbF, CsF etc. Compounds such as phosphates such as K ₂ HPO ₄ , KH ₂ PO ₄ , Na ₃ PO ₄ , Na ₂ HPO ₄ , NaH ₂ PO ₄ , Li ₂ HPO ₄ , LiH ₂ PO ₄ etc. it can.

  Here, when the inorganic fluorescent substance 11 is dispersed in the transparent resin 12, the particle diameter of the inorganic fluorescent substance 11 is miniaturized to about several tens of nm in order not to reduce the transmittance of visible light and infrared light. It is preferable that the refractive index of the inorganic phosphor 11 be approximately the same as that of the transparent resin 12. However, as the particle diameter of the inorganic phosphor 11 is larger, the defect density in the inorganic phosphor becomes smaller and the energy loss at the time of light emission decreases, so that the light emission efficiency becomes higher. Therefore, in order not to reduce the transmittance of visible light and infrared light, it is preferable that the refractive index of the inorganic phosphor 11 be approximately the same as that of the transparent resin 12. Therefore, it is preferable that the refractive index difference of the inorganic fluorescent substance 11 and the transparent resin 12 is less than 0.03.

  In the wavelength conversion filter of the present embodiment, the content of the inorganic phosphor 11 in the transparent resin 12 is preferably 0.1% by volume or more and less than 10% by volume, and is 1% by volume or more and less than 5% by volume More preferable. As a result, it is possible to obtain a wavelength conversion filter in which ultraviolet light is sufficiently absorbed and a decrease in transmittance of visible light and infrared light is suppressed.

  The wavelength conversion filter of the present embodiment can be manufactured by mixing the inorganic phosphor 11 with the transparent resin 12 and molding it into a sheet, film, plate, dome or any other desired shape. Moreover, it can also apply and shape | mold on transparent resin 12 or a board | substrate, and can also produce. In addition, although the thickness of a wavelength conversion filter is not specifically limited, For example, it is preferable to be referred to as 200 micrometers-1000 micrometers.

  Thus, in the wavelength conversion filter according to the present embodiment, the solubility in water is 0.1 or more, and the inorganic phosphor 11 whose base crystal is a fluorophosphate has a water absorption rate of 0.1%. And a transparent resin 12 for dispersing the inorganic phosphor 11. Therefore, even if the solubility of the inorganic phosphor 11 is high, the water absorption of the transparent resin 12 is low, so the contact ratio between the inorganic phosphor 11 and water decreases, and the decomposition of the inorganic phosphor 11 is suppressed. It becomes possible. Moreover, since the luminescence intensity is high and the quantum efficiency is high even when the temperature of the inorganic phosphor 11 whose host crystal is fluorophosphate is high, the wavelength conversion efficiency of the wavelength conversion filter can be further improved.

[Solar cell module]
Next, the solar cell module according to the present embodiment will be described. As shown in FIG. 4, the solar cell module 100 includes a solar cell 20 as a photoelectric conversion cell, a wavelength conversion filter 10 disposed on the light receiving surface 23 side of the solar cell 20, and a surface of the wavelength conversion filter 10. And a surface protection member 30 disposed. In addition, the solar cell module 100 includes a back surface sealing member 40 disposed on the back surface 24 which is a surface opposite to the light receiving surface 23 of the solar battery cell 20, and a back surface protective material disposed on the back surface of the back surface sealing member 40. And 50. That is, in the solar cell module 100, the surface protection material 30, the wavelength conversion filter 10, the solar battery cell 20, the back surface sealing member 40, and the back surface protection material 50 are provided in this order from the top in the figure. .

  The photovoltaic cell 20 absorbs light incident from the light receiving surface 23 of the photovoltaic cell 20 to generate photovoltaic power. The solar battery cell 20 is formed using, for example, a semiconductor material such as crystalline silicon, gallium arsenide (GaAs), indium phosphide (InP) or the like. Specifically, the solar battery cell 20 is made of, for example, a stack of crystalline silicon and amorphous silicon. Electrodes (not shown) are provided on the light receiving surface 23 of the solar battery cell 20 and the back surface 24 which is the surface opposite to the light receiving surface 23. The photovoltaic power generated by the solar battery cell 20 is supplied to the outside through the electrode.

  The wavelength conversion filter 10 is disposed on the light receiving surface 23 of the solar battery cell 20. As shown in FIG. 4, the wavelength conversion filter 10 includes a transparent resin 12 for sealing the light receiving surface 23 of the solar battery cell 20 and an inorganic phosphor 11 dispersed in the transparent resin 12. The wavelength conversion filter 10 prevents penetration of moisture into the solar battery cell 20 by the transparent resin 12 and improves the strength of the entire solar battery module 100.

  The surface protective material 30 is provided on the light receiving surface 23 side of the solar battery cell 20, and protects the solar battery cell 20 from the external environment and transmits light to be absorbed by the solar battery cell 20. For example, a glass substrate can be used as the surface protective material 30. In addition to the glass substrate, the surface protection material 30 may be polycarbonate, acrylic resin, polyester, or fluorinated polyethylene. The back surface protective material 50 is a back sheet provided on the back surface 24 side of the solar battery cell 20. The back surface protective material 50 may be a transparent substrate made of the same glass or plastic as the surface protective material 30.

  The back surface sealing member 40 is disposed on the back surface 24 of the solar battery cell 20 to prevent the entry of moisture into the solar battery cell 20 and improve the strength of the entire solar battery module 100. The back surface sealing member 40 is made of, for example, the same material as the material that can be used for the transparent resin 12 of the wavelength conversion filter 10. The material of the back surface sealing member 40 may be the same as or different from the material of the transparent resin 12 of the wavelength conversion filter 10.

  In addition, a metal foil or the like may be provided between the back surface sealing member 40 and the back surface protective material 50 so that the light incident from the front surface protective material 30 side is more absorbed by the solar battery cell 20. Thereby, the light reaching the back surface protective material 50 from the front surface protective material 30 can be reflected in the direction of the solar battery cell 20.

  When the solar cell module 100 is irradiated with sunlight including ultraviolet light 70 and visible light and infrared light 80, the ultraviolet light 70 and visible light and infrared light 80 pass through the surface protection material 30, The light is incident on the wavelength conversion filter 10. The visible light and the infrared light 80 incident on the wavelength conversion filter 10 are transmitted through the wavelength conversion filter 10 as they are without being substantially converted by the inorganic fluorescent substance 11, and are irradiated to the solar battery cell 20. On the other hand, the ultraviolet light 70 incident on the wavelength conversion filter 10 is converted to visible light and infrared light 80 which are light on the long wavelength side by the inorganic fluorescent substance 11, and is then irradiated to the solar battery cell 20. The solar battery cell 20 generates a photovoltaic power 90 by the visible light and infrared light 80 irradiated, and the photovoltaic power 90 is supplied to the outside of the solar battery module 100 through a terminal (not shown).

  Thus, the solar cell module 100 according to the present embodiment includes the photoelectric conversion cell (solar battery cell 20), the surface protection material 30 for protecting the light incident side to the photoelectric conversion cell, the photoelectric conversion cell, and And a wavelength conversion filter 10 provided between the surface protection member 30. In addition, the wavelength conversion filter 10 includes an inorganic phosphor 11 having a water solubility of 0.1 or more, and a transparent resin 12 having a water absorption coefficient of 0.1% or less and dispersing the inorganic phosphor 11. Prepare. As a result, the contact ratio between the inorganic phosphor 11 and water decreases, and the decomposition of the inorganic phosphor 11 can be suppressed. Further, since the wavelength conversion filter 10 uses the inorganic phosphor 11 in which the host crystal is a fluorophosphate, the decrease in the internal quantum efficiency at high temperature is largely suppressed, and the temperature characteristics are improved. Therefore, the output of the solar cell module 100 can be improved even at high temperatures.

  Hereinafter, the present embodiment will be described in more detail by way of examples and comparative examples, but the present embodiment is not limited to these examples.

[Preparation of Inorganic Phosphor]
First, an inorganic phosphor was synthesized using a preparation method utilizing a solid phase reaction. In addition, in the said inorganic fluorescent substance, the following compound powder was used as a raw material.

Sodium carbonate (Na ₂ CO ₃ ): purity 2N8, Wako Pure Chemical Industries, Ltd. sodium fluoride (NaF): purity 2 N, Wako Pure Chemical Industries, Ltd. magnesium oxide (MgO): purity 4 N, high purity chemical Laboratory-made europium fluoride (EuF ₃ ): purity 3N, Wako Pure Chemical Industries, Ltd. diammonium hydrogen phosphate ((NH ₄ ) ₂ HPO ₄ ): purity 2N, Wako Pure Chemical Industries, Ltd.

First, 1.0599 g of sodium carbonate, 1.0077 g of sodium fluoride, 0.7981 g of magnesium oxide, 0.0418 g of europium fluoride, and 2.6412 g of diammonium hydrogen phosphate were prepared. Next, the raw materials were sufficiently dry-mixed using a magnetic mortar and a magnetic pestle to obtain sintered raw materials. Thereafter, the fired material was transferred to an alumina crucible and fired at a temperature of 800 ° C. for 2 hours using an air atmosphere furnace. Then, the fired product was crushed using an alumina mortar and an alumina pestle. The crushed sample was transferred to an alumina crucible and fired for 2 hours in a reducing atmosphere (in a 96% nitrogen 4% hydrogen mixed gas atmosphere) at a temperature of 800 ° C. using a tubular atmosphere furnace. Thereafter, the fired product was crushed using an alumina mortar and an alumina pestle. In this way, an inorganic phosphor having a composition formula represented by Na ₂ Mg _0.99 Eu _0.01 PO ₄ F was obtained. In addition, since the host crystal of the inorganic phosphor is a fluorophosphate and further contains sodium, the solubility in water was 0.1 or more.

[Production of wavelength conversion filter]
The wavelength conversion filters of Examples and Comparative Examples were produced as follows using the inorganic phosphors obtained by the method described above.

(Example)
First, the above-mentioned inorganic fluorescent substance and the sealing material were weighed so that the content of the inorganic fluorescent substance in the sealing material would be 5% by volume. As a sealing material, Kernel (registered trademark) manufactured by Japan Polyethylene Corporation, which is an ethylene-α-olefin copolymer, was used. The water absorption of the ethylene-α-olefin copolymer was less than 0.01%.

  Next, using a plastmill manufactured by Toyo Seiki Co., Ltd., the inorganic phosphor and the encapsulant are melt-kneaded at a heating temperature of 150 ° C. and a rotation speed of 30 rpm for 30 minutes to obtain an inorganic phosphor and the encapsulant. A mixture of Then, the obtained mixture was subjected to heating and pressing at a temperature of 150 ° C. and a pressing pressure of 1.5 MPa using a heating press. Thereby, the wavelength conversion filter of the Example which is 0.6 mm in thickness and is sheet-like was obtained.

(Comparative example)
Comparative Example in the same manner as in Example except that ethylene-α-olefin copolymer as a sealing material was changed to ethylene-vinyl acetate copolymer (Evaflex (registered trademark) EV450) manufactured by Mitsui DuPont Co., Ltd. Wavelength conversion filter was obtained. The water absorption of the ethylene-vinyl acetate copolymer was 0.15%.

[Evaluation]
Moisture resistance evaluation was implemented with respect to the wavelength conversion filter of an Example and a comparative example. Specifically, first, the internal quantum efficiencies of the wavelength conversion filters of the example and the comparative example obtained as described above were measured. Next, the wavelength conversion filters of the example and the comparative example were placed in an 80 ° C. constant temperature bath having a relative humidity of 85% and left for 2000 hours. Then, the internal quantum efficiencies of the wavelength conversion filters were measured when 24 hours, 72 hours, 217 hours, 240 hours, 360 hours, 500 hours, 1200 hours and 2000 hours had elapsed. The relationship between the internal quantum efficiency maintenance rate and the elapsed time at each time is shown in FIG. The internal quantum efficiency maintenance factor is a value obtained by dividing the internal quantum efficiency at each time by the internal quantum efficiency at 0 hour.

The measurement of the internal quantum efficiency of the wavelength conversion filter was performed using the quantum efficiency measurement system QE-1100 manufactured by Otsuka Electronics Co., Ltd. The measurement and analysis conditions are as follows.
Excitation wavelength: 350 nm
Integration number: 100 times Exposure time: Auto Measurement temperature range: 30 ° C
Excitation light wavelength range: ± 20 nm
Fluorescence wavelength range: 370 nm to 800 nm

  As shown in FIG. 5, it can be seen that, in the wavelength conversion filter of the example, the internal quantum efficiency is not significantly reduced even after 2000 hours under high temperature and high humidity conditions. On the other hand, in the wavelength conversion filter of the comparative example, the internal quantum efficiency is half or less of the initial one, and it is understood that the moisture resistance is inferior.

  In the wavelength conversion filter of the example, the decrease rate of the internal quantum efficiency after leaving for 1200 hours was 20% or less of the initial rate. On the other hand, in the wavelength conversion filter of the comparative example, the decrease rate of the internal quantum efficiency after leaving for 1200 hours was over 50% of the initial rate. This also shows that the wavelength conversion filter of the example is excellent in moisture resistance at high temperature.

  As described above, even in the case of using an inorganic phosphor having high solubility in water, when it is dispersed in a transparent resin having a water absorption of 0.1% or less, high moisture resistance over a long period of time is obtained. It is understood that it can be obtained.

  Next, the characteristics of the inorganic phosphor used in the wavelength conversion filter of the present embodiment will be described in more detail by reference examples and reference comparative examples.

[Preparation of Inorganic Phosphor]
The inorganic phosphors of Reference Examples 1 to 4 and Reference Comparative Example 1 were synthesized using a preparation method utilizing a solid phase reaction, and the characteristics thereof were evaluated. In addition, in the reference example and the reference comparative example, the following compound powder was used as a raw material.

Sodium carbonate (Na ₂ CO ₃ ): purity 2N8, Wako Pure Chemical Industries, Ltd. lithium carbonate (Li ₂ CO ₃ ): purity 3N5, Kanto Chemical Co., Ltd. sodium fluoride (NaF): purity 2 N, Wako Pure Chemical Industries Calcium carbonate (CaCO ₃ ), Inc .: Purity 2N5, Kanto Chemical Co., Ltd. Magnesium oxide (MgO): Purity 4N, High Purity Chemical Research Institute, Inc. Magnesium fluoride (MgF ₂ ): Purity> 2N, Morita Chemical Industries Europium oxide (Eu ₂ O ₃ ): Purity 4 N, Shin-Etsu Chemical Co., Ltd. Europium fluoride (EuF ₃ ): Purity 3 N, Wako Pure Chemical Industries, Ltd. Diammonium hydrogen phosphate ((NH ₄ ) ₂ HPO _4): purity 2N, manufactured by Wako pure Chemical Industries, Ltd. silicon dioxide _(SiO 2): purity> 3N, Nippon Aerosil stock Society Made by

  First, each raw material was measured in the ratio shown in Table 1 regarding the reference examples 1 to 4. Next, the raw materials were sufficiently dry-mixed using a magnetic mortar and a magnetic pestle to obtain sintered raw materials. Thereafter, the fired material was transferred to an alumina crucible and fired at a temperature of 800 ° C. or 820 ° C. for 2 hours using an air atmosphere furnace. Then, the fired product was crushed using an alumina mortar and an alumina pestle. The crushed sample was transferred to an alumina crucible and fired for 2 hours in a reducing atmosphere (in a 96% nitrogen 4% hydrogen mixed gas atmosphere) at a temperature of 800 ° C. or 820 ° C. using a tubular atmosphere furnace. Thereafter, the fired product was crushed using an alumina mortar and an alumina pestle.

Thus, the inorganic phosphor of the reference example 1 represented by the composition formula Na ₂ Mg _0.99 Eu _0.01 PO ₄ F, and the composition formula Na _1.99 Eu _0.01 Mg _0.01 The inorganic phosphor of Reference Example 2 represented by Li _0.01 PO ₄ F was obtained. Furthermore, the inorganic phosphor of Reference Example 3 represented by the composition formula Na _1.99 Eu _0.01 MgP _0.99 Si _0.01 O ₄ F, and the composition formula Na ₂ Mg _0.98 Eu _0. An inorganic phosphor of Reference Example 4 represented by ₀₁ Mn _0.01 PO ₄ F was obtained.

  In addition, when ultraviolet light (wavelength 365 nm) was irradiated to the obtained inorganic fluorescent substance of the reference example 1 thru | or 3, blue fluorescence was visually observed in any case. Moreover, when the ultraviolet light (wavelength 365nm) was irradiated to the inorganic fluorescent substance of the reference example 4 obtained, the fluorescence of the whiteness purple color was visually observed.

With regard to Reference Comparative Example 1, first, each raw material was weighed at a ratio shown in Table 1. Next, the raw materials were sufficiently dry-mixed using a magnetic mortar and a magnetic pestle to obtain sintered raw materials. Thereafter, the fired material was transferred to an alumina crucible and fired at a temperature of 900 ° C. for 2 hours using an air atmosphere furnace. Then, the fired product was crushed using an alumina mortar and an alumina pestle. The crushed sample was transferred to an alumina crucible and fired for 2 hours in a reducing atmosphere (in a 96% nitrogen 4% hydrogen mixed gas atmosphere) at a temperature of 900 ° C. using a tubular atmosphere furnace. Thereafter, the fired product was crushed using an alumina mortar and an alumina pestle. Thus, the inorganic phosphor of Reference Comparative Example 1 represented by the composition formula Na ₂ Ca _0.99 Eu _0.01 PO ₄ F was obtained.

  In addition, when an ultraviolet-ray (wavelength 365nm) was irradiated to the obtained inorganic fluorescent substance of the reference comparative example 1, green fluorescence was visually observed.

[Evaluation]
<Excitation characteristics and light emission characteristics>
The excitation characteristics and the light emission characteristics of the inorganic phosphors of Reference Examples 1 to 4 and Reference Comparative Example 1 were evaluated. Specifically, the excitation spectrum and the emission spectrum were measured using a spectrofluorimeter (FP-6500) manufactured by JASCO Corporation. In addition, the excitation wavelength at the time of emission spectrum measurement was made into the excitation peak wavelength, and the monitor wavelength at the time of excitation spectrum measurement was made into the emission peak wavelength.

  FIG. 6 shows the excitation spectrum and the emission spectrum of the inorganic phosphors of Reference Example 1 and Reference Comparative Example. As shown in FIG. 6, it was found that the inorganic phosphors of Reference Example 1 and Reference Comparative Example can be excited by ultraviolet light of 300 to 400 nm. In addition, it was found that the inorganic fluorescent substance of Reference Comparative Example had an emission peak wavelength of around 510 nm, while the inorganic fluorescent substance of Reference Example 1 had an emission peak wavelength of around 440 nm.

  FIG. 7 shows the excitation spectrum and the emission spectrum of the inorganic phosphor of Reference Example 2. As shown in FIG. 7, the inorganic phosphor of Reference Example 2 exhibited the same excitation spectrum and emission spectrum as the inorganic phosphor of Reference Example 1. Further, FIG. 8 shows an excitation spectrum and an emission spectrum of the inorganic phosphor of Reference Example 3. As shown in FIG. 8, the inorganic phosphor of Reference Example 3 also exhibited the same excitation spectrum and emission spectrum as the inorganic phosphor of Reference Example 1.

FIG. 9 shows an excitation spectrum and an emission spectrum of the inorganic phosphor of Reference Example 4. Unlike the inorganic phosphor of Reference Example 1, the inorganic phosphor of Reference Example 4 exhibited light emission consisting of a first emission peak around 440 nm and a second emission peak around 604 nm. This is accomplished by further comprising a ^{Mn 2+} In addition to ^{Eu 2+,} it is considered that the second light emission occurs with a peak 604 nm. That is, the second light emission is considered to be light emission with Mn ²⁺ as the light emission center.

Also, as shown in FIG. 9, when the excitation spectrum was measured with both 440 nm and 604 nm as monitor wavelengths, the excitation spectrum shape was similar when monitoring with either peak. From this, it is considered that energy transfer occurs in which the energy absorbed by Eu ²⁺ is transferred to Mn ²⁺ .

<Internal quantum efficiency>
The internal quantum efficiencies of the inorganic phosphors obtained in Reference Examples 1 and 4 and Reference Comparative Example were measured. The measurement of the quantum efficiency of the inorganic phosphor was performed using a quantum efficiency measurement system QE-1100 manufactured by Otsuka Electronics Co., Ltd. The measurement and analysis conditions are as follows.
Excitation wavelength: 350 nm
Integration number: 100 times Exposure time: Auto Measurement temperature range: 30 ° C to 200 ° C
Excitation light wavelength range: ± 20 nm
Fluorescence wavelength range: 370 nm to 800 nm

  FIG. 10 shows the temperature dependency of the internal quantum efficiency in the inorganic phosphors of Reference Example 1 and Reference Comparative Example. That is, FIG. 10 shows relative internal quantum efficiencies at respective temperatures when the internal quantum efficiency at 30 ° C. is 100% for the inorganic phosphors of Reference Example 1 and Reference Comparative Example.

  As shown in FIG. 10, it can be seen that the inorganic phosphor of Reference Example 1 exhibits high internal quantum efficiency even at high temperature with respect to the inorganic phosphor of Reference Comparative Example. Specifically, while the inorganic phosphor of Reference Comparative Example has a relative internal quantum efficiency of 50% or less at 150 ° C., the inorganic phosphor of Reference Example 1 has a relative internal quantum efficiency of 96 at 150 ° C. %Met. Furthermore, the inorganic phosphor of Reference Example 1 exhibited a high relative internal quantum efficiency of 94% at 170 ° C. and 92% at 190 ° C. Thus, although the inorganic phosphor of the reference comparative example has a large decrease in internal quantum efficiency at high temperatures, the inorganic phosphor of the reference example 1 has lower quantum efficiency even at high temperatures compared to the inorganic phosphor of the reference comparative example. It turns out that it is difficult to do.

  FIG. 11 shows the temperature dependency of the internal quantum efficiency in the inorganic phosphor of Reference Example 4. That is, FIG. 11 shows relative internal quantum efficiencies at respective temperatures when the internal quantum efficiency at 30 ° C. is 100% for the inorganic phosphor of Reference Example 4.

  As shown in FIG. 11, it can be seen that the quantum efficiency of the inorganic phosphor of Reference Example 4 is unlikely to decrease even at high temperature, similarly to the inorganic phosphor of Reference Example 1. Specifically, the inorganic phosphor of Reference Example 4 had a relative internal quantum efficiency of 92% at 150 ° C. Furthermore, the inorganic phosphor of Reference Example 4 exhibited a relative internal quantum efficiency as high as 92% at 170 ° C. and 92% at 190 ° C.

<Refractive index>
The refractive index of the inorganic phosphor of Reference Example 1 was measured. The refractive index of the inorganic phosphor was measured by the Becke line method (based on JIS K7142 B method) using an Abbe refractometer NAR-2T manufactured by Atago Co., Ltd. and a polarizing microscope BH-2 manufactured by Olympus Co., Ltd. The measurement conditions are as follows.
Immersion liquid: Propylene carbonate (n _D ²³ 1.420)
Butyl phthalate (n _D ²³ 1.491)
Bromonaphthalene (n _D ²³ 1.657)
Temperature: 23 ° C
Light source: Na (D line / 589 nm)

  As a result of the measurement, it was found that the refractive index of the inorganic phosphor of Reference Example 1 was 1.501 to 1.509 according to the measurement by the Becke line method. From this, it can be said that the inorganic fluorescent substance of the reference example 1 has a refractive index similar to that of the transparent resin of the present embodiment, and the wavelength conversion filter in which the inorganic fluorescent substance is dispersed in the transparent resin exhibits high translucency.

  Although the contents of the present embodiment have been described above according to the examples, the present embodiment is not limited to these descriptions, and it is obvious to those skilled in the art that various modifications and improvements are possible. is there.

10 Wavelength Conversion Filter 11 Inorganic Phosphor 12 Transparent Resin 20 Photoelectric Conversion Cell (Solar Battery Cell)
30 surface protection material 100 solar cell module

Claims (4)

Inorganic phosphors having a solubility in water of at least 0.1 and a host crystal of which is a fluorophosphate;
A transparent resin having a water absorption rate of 0.1% or less and dispersing the inorganic phosphor;
, A wavelength conversion filter. The wavelength conversion filter according to claim 1, wherein the inorganic phosphor is a phosphor in which a part of constituent elements of the compound represented by the general formula (1) is substituted with at least one of Ce ³⁺ and Eu ²⁺ .
A ₂ MPO ₄ X (1)
(Wherein, A is an alkali metal element and contains at least Na, M is an element selected from the group consisting of Mg, Ca, Sr, Ba, and Zn, contains at least Mg, and X is a halogen element And at least include F.) The wavelength conversion filter according to claim 1, wherein the inorganic phosphor is a phosphor in which a part of constituent elements of Na ₂ MgPO ₄ F is substituted with at least one of Ce ³⁺ and Eu ²⁺ . Photoelectric conversion cell,
A surface protection material for protecting the light incident side to the photoelectric conversion cell;
The wavelength conversion filter according to any one of claims 1 to 3, provided between the photoelectric conversion cell and the surface protection material;
, A solar cell module.

Images