JP2018163959A - Solar cell module and method for manufacturing photoelectric conversion element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that when light absorption layers of a plurality of solar cells are continuously formed in an inert atmosphere, conversion efficiency in the solar cells is deteriorated in accordance with an increase in the number of continuously formed batches.SOLUTION: A solar cell module comprises: a light absorption layer containing a perovskite compound; an electronic transport layer arranged on one side of the light absorption layer; a hole transport layer arranged on the other side of the light absorption layer; and a transparent electrode layer. The perovskite compound has a (002) diffraction peak which appears in the vicinity of 2θ=13.9° and a (110) diffraction peak which appears in the vicinity of 2θ=14° in X ray diffraction measurement by a θ-2θ method, and a peak intensity ratio I(110)/I(002) of an intensity I(002) of a peak of a (002) surface and an intensity I(110) of a peak of a (110) surface is 1.35 to 3.00, and the electronic transport layer or the hole transport layer are formed by combining a plurality of photoelectric conversion elements arranged on the transparent electrode layer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a solar cell module and a method for manufacturing a photoelectric conversion element.

Solar cells (perovskite solar cells) using organometallic perovskite crystals as a light absorbing layer can achieve high conversion efficiency, and many reports have been made in recent years (for example, Patent Document 1 and Non-Patent Documents). Reference 1). As the organic metal, for example, a compound represented by the general formula ABX ₃ (wherein A is a monovalent cation, B is a divalent metal ion, and X is a halogen) is used. . Among these, perovskite crystals such as CH ₃ NH ₃ PbX ₃ (X: halogen) can be formed at low cost by solution coating such as spin coating. Therefore, perovskite solar cells using such a perovskite crystal are attracting attention as low-cost and high-efficiency next-generation solar cells.

JP 2014-72327 A

G. Hodes, Science, 342, 317-318 (2013)

  In a perovskite solar cell, a light absorption layer is generally formed in an inert atmosphere. However, it has been found that when the light absorption layers of a plurality of solar cells are continuously formed in an inert atmosphere, the conversion efficiency of the solar cells decreases as the number of continuously formed batches increases. Industrial production of solar cells is carried out continuously. When these solar cells having variations in conversion efficiency are connected in series to form a module, the solar cell module has the smallest current value. Current is determined, and the module efficiency of the solar cell module is reduced. When a plurality of solar cells are connected in parallel to form a module, the voltage of the solar cell module is determined by the voltage of the solar cell that exhibits the smallest voltage value. That is, in a solar cell module in which a plurality of solar cells are connected in series and / or in parallel, the module efficiency is affected by the solar cell having the lowest characteristics, and the module efficiency is greatly reduced.

  In view of the above, an object of the present invention is to solve the above problems and provide a perovskite solar cell module having high conversion efficiency.

The solar cell module of the present invention includes a light absorption layer containing a perovskite compound, an electron transport layer disposed on one side of the light absorption layer, a hole transport layer disposed on the other side of the light absorption layer, and a transparent Having an electrode layer,
The perovskite compound is
General formula:
ABX ₃
(In the general formula, A is a monovalent cation, B is a divalent metal ion, and X is independently F, Cl, Br, or I.)
Represented by
The perovskite compound has a (002) diffraction peak appearing in the vicinity of 2θ = 13.9 ° and a (110) diffraction peak appearing in the vicinity of 2θ = 14 ° in the X-ray diffraction measurement by the θ-2θ method. (002) The peak intensity ratio I (110) / I (002) between the peak intensity I (002) of the plane and the peak intensity I (110) of the (110) plane is 1.35 to 3.00,
The electron transport layer or the hole transport layer is formed by combining a plurality of photoelectric conversion elements arranged on the transparent electrode layer.

  In one embodiment, the peak intensity ratio is 1.50 to 2.00.

  In one embodiment, the electron transport layer or the hole transport layer is formed on a transparent electrode layer having a haze ratio of 5% to 20%.

  In one embodiment, the haze ratio is 10% to 15%.

  In one embodiment, it has another photoelectric conversion unit which performs photoelectric conversion.

  In one embodiment, the another photoelectric conversion unit includes a crystalline silicon substrate.

The said photoelectric conversion element is produced with the following manufacturing methods. A plurality of photoelectric conversions having a light absorption layer containing a perovskite compound on a substrate, an electron transport layer disposed on one side of the light absorption layer, and a hole transport layer disposed on the other side of the light absorption layer A method for manufacturing an element, comprising:
In the step of forming a light absorption layer containing a perovskite compound on the plurality of substrates,
Forming the light absorption layer on the first substrate in an inert gas atmosphere;
Replacing the inert gas with a new inert gas;
Forming the light absorption layer on the second substrate in the new inert gas atmosphere;
Are performed in this order.

  A perovskite photoelectric conversion element including a light absorption layer having a predetermined XRD peak can be continuously produced. Moreover, according to the present invention, a highly efficient perovskite solar cell module can be provided.

It is a figure which shows typically the cross section of the photoelectric conversion element in one Embodiment of this invention. It is a schematic sectional drawing of the lamination type photoelectric conversion element in one Embodiment of this invention. It is a figure which shows the example which fitted the XRD measurement result by the least squares method by the pseudo Voith function.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the following embodiments.

  As schematically shown in FIG. 1, a photoelectric conversion element (typically a solar cell) 10 according to an embodiment of the present invention includes a transparent substrate 1, a transparent electrode layer 2, an electron transport layer 3, and a perovskite compound. It has the light absorption layer 4, the hole transport layer 5, and the metal electrode layer 6 in this order. The electron transport layer 3 and the hole transport layer 5 may be interchanged.

  As the transparent substrate 1, typically, a transparent substrate having a light-transmitting property such as glass or a film is used. As the glass, for example, alkali-free glass can be used. As the film, for example, PET, aramid film, polyimide film or the like can be used.

  Examples of the transparent electrode layer 2 include a single layer film such as fluorine-doped tin oxide (FTO), indium tin oxide (ITO), and zinc oxide (ZnO), or a stacked film formed by stacking these layers. From the viewpoint of moisture resistance, it is preferable to use FTO. The film thickness of the transparent electrode layer is preferably 500 nm to 1000 nm, and more preferably 650 nm to 1000 nm, for example, from the viewpoint of resistivity. The haze ratio of the transparent electrode layer is, for example, preferably 5% to 20% and more preferably 10% to 15% from the optical viewpoint. The haze ratio can be measured according to JIS K7136. The transparent electrode layer may be produced by any appropriate film forming method depending on the forming material. For example, spray pyrolysis is preferable.

The electron transport layer 3 can be formed of any appropriate material. Examples of the material for forming the electron transport layer include inorganic materials typified by metal oxides such as titanium oxide, zinc oxide, niobium oxide, zirconium oxide and aluminum oxide, and fullerene materials such as phenyl _C61 butyric acid methyl ester. And organic materials such as perylene-based materials. Among these, inorganic materials are preferably used. A donor may be added to the electron transport layer. As a specific example, when titanium oxide is used as the material for forming the electron transport layer, yttrium, europium, terbium, or the like is used as a donor.

The electron transport layer 3 includes a blocking layer 3a. The blocking layer 3a is a layer that can suppress electron transport and reverse electron transfer. The blocking layer is preferably a layer made of a metal oxide such as TiO ₂ or ZnO, among which compact TiO ₂ is preferable. By using such a material, for example, as shown in FIG. 1, the surface of the transparent electrode layer 2 can be densely covered. The film thickness of the blocking layer is preferably 5 nm to 100 nm, and more preferably 10 nm to 50 nm, for example, from the viewpoint of optical and electron injection.

  In one embodiment, as shown in FIG. 1, the electron transport layer 3 preferably further includes a porous carrier layer 3b in addition to the blocking layer 3a. The porous carrier layer 3b is formed on the side where the light absorption layer 4 on the blocking layer 3a is disposed. By providing the porous carrier layer, the coating property of the light absorption layer is improved.

  The photoelectric conversion element is typically manufactured by sequentially laminating each layer on a substrate. In this case, as shown in FIG. 1, in the form in which the electron transport layer 3 is arranged closer to the transparent substrate 1 than the light absorption layer 4, the light absorption layer 4 is formed after the electron transport layer 3 is formed.

As a material for forming the porous carrier layer, it is preferable to include a component included in the material for forming the blocking layer. This is because the adhesion with the blocking layer can be improved. As a result, the adhesion between the electron transport layer and the light absorption layer can be improved. For example, as a material for forming the porous carrier layer, a metal oxide can be used, and among them, porous TiO ₂ or Al ₂ O ₂ is preferably used. The film thickness of the porous carrier layer is preferably 50 nm to 300 nm, more preferably 100 nm to 200 nm. By setting it as such a range, it can be expected that, for example, a light absorption layer having a perovskite crystal structure, which will be described later, is favorably formed while reducing optical absorption loss.

  The electron transport layer 3 can be formed by any appropriate method depending on the forming material. Examples of the forming method include dry processes such as vacuum deposition, CVD, and sputtering, and wet processes such as spin coating, spraying, and bar coating.

The light absorption layer 4 includes a photosensitive material (perovskite compound) having a perovskite crystal structure. The perovskite compound is represented by the general formula ABX ₃ . In the formula, A is a monovalent cation. Examples of monovalent cations include monovalent cations such as alkali metal cations and organic cations. More specifically, examples include methylammonium cation (CH ₃ NH ₃ ⁺ ), formamidinium cation (NH ₂ CHNH ₂ ⁺ ), and cesium cation (Cs ⁺ ). You may mix. B is a divalent metal ion, preferably Pb or Sn. X is a halogen, and examples thereof include F, Cl, Br, and I. All three Xs may be the same halogen element, or a plurality of halogen elements may be mixed. For example, the spectral sensitivity characteristics can be changed by changing the type and ratio of halogen. The light absorption layer 4 has a (002) diffraction peak appearing in the vicinity of 2θ = 13.9 ° and a (110) diffraction peak appearing in the vicinity of 2θ = 14 ° in X-ray diffraction measurement by the θ-2θ method using CuKα rays. The peak intensity ratio I (110) / I (002) of the peak intensity I (002) on the (002) plane and the peak intensity I (110) on the (110) plane is 1.50 to 3.00. As a result, a highly efficient perovskite photoelectric conversion element is formed. Further, the peak intensity ratio I (110) / I (002) is more preferably 1.50 to 2.00. The film thickness of the light absorption layer 4 is preferably 50 nm to 700 nm. For example, 200 nm to 500 nm is more preferable from the viewpoint of light absorption efficiency and exciton diffusion length.

The light absorption layer containing the perovskite compound can be formed on the substrate by a dry process or a wet process, like the electron transport layer. These processes are carried out in an inert gas atmosphere such as argon or nitrogen under a hermetic seal such as a glove box. The light absorption layer containing a perovskite compound is formed, for example, by applying a coating liquid (for example, a solution) containing a material constituting the perovskite compound by a spin coating method or the like. Specifically, when CH ₃ NH ₃ PbI ₃ is used as the perovskite compound, a solution obtained by mixing lead iodide and methylammonium iodide in a solvent such as dimethyl sulfoxide or N, N-dimethylformamide is spin-coated. The CH ₃ NH ₃ PbI ₃ crystal can be grown by applying the coating method and heating the coating film. Crystallinity can also be improved by bringing a poor solvent into contact with the surface of the coating film. In the case where a plurality of light absorption layers are continuously formed, if a solvent such as dimethyl sulfoxide or N, N-dimethylformamide is excessively present in the formation atmosphere of the light absorption layer, the formation of the perovskite compound is inhibited. Before forming the light absorption layer of each photoelectric conversion element, the replacement work of the atmosphere in which the light absorption layer is formed is performed with a new inert gas such as argon or nitrogen. The replacement work with a new inert gas does not need to be performed every time before the formation of the light absorption layer. After the formation of a plurality of light absorption layers without performing the replacement work of the inert gas, a new work is performed. A replacement operation with an inert gas may be performed, and then a plurality of light absorption layers may be formed. In the case where a light absorption layer having a large area such as roll-to-roll is formed at a time, an operation for replacing the atmosphere in which the light absorption layer is formed with a new inert gas is performed as appropriate.

A light absorption layer containing a perovskite compound can also be formed by a combination of a dry process and a wet process. For example, a lead iodide thin film is formed by a vacuum evaporation method, and a crystal of CH ₃ NH ₃ PbI ₃ is obtained by bringing a isopropyl alcohol solution of methylammonium iodide into contact with the surface. Examples of the method of bringing the solution into contact with the surface of the deposited film include a method of applying the solution by spin coating or the like, and a method of immersing the deposited film in the solution. For example, when a texture structure is formed on the light incident side of a silicon substrate, which will be described later, the dipping method is preferably used from the viewpoint of uniformly contacting the solution.

The hole transport layer 5 may be appropriately selected from conventionally known materials, for example, polythiophene derivatives such as poly-3-hexylthiophene (P3HT) and poly (3,4-ethylenedioxythiophene) (PEDOT), 2 , 2 ′, 7,7′-tetrakis- (N, N-di-p-methoxyphenylamine) -9,9′-spirobifluorene (Spiro-OMeTAD), carbazole derivatives such as polyvinylcarbazole, Examples include triphenylamine derivatives, diphenylamine derivatives, polysilane derivatives, polyaniline derivatives, and the like. The material of the hole transport layer, also include MoO _3, WO _3, NiO metal oxides such like.

  The hole transport layer may be a single layer or a laminated structure composed of a plurality of layers. The thickness of the hole transport layer is preferably 1 nm to 200 nm.

  The hole transport layer is formed on the light absorption layer 4 by a spray method or the like using a solution containing a hole transport material such as Spiro-OMeTAD described above.

  As a material for forming the metal electrode layer 6, for example, a metal such as gold or silver is used. A known technique such as a PVD method such as a sputtering method or an ion plating method or resistance heating may be used for forming the metal electrode, and the sputtering method is preferable from the viewpoint of productivity. Sputter deposition is typically performed while introducing an inert gas such as argon or nitrogen into a deposition chamber (chamber).

  Although not shown, for example, a hole injection layer such as molybdenum oxide may be formed between the hole transport layer 5 and the metal electrode layer 6 in order to improve carrier injection characteristics.

  FIG. 2 is a schematic cross-sectional view of a stacked photoelectric conversion element according to an embodiment of the present invention. The photoelectric conversion element 100 includes a first photoelectric conversion unit (top cell) 20 and a second photoelectric conversion unit (bottom cell) 30 in this order from the light incident side (upper side in the drawing).

  As one of the photoelectric conversion units constituting the stacked photoelectric conversion element, a perovskite photoelectric conversion unit having a light absorption layer containing the perovskite compound is employed. In FIG. 2, a perovskite photoelectric conversion unit is employed as the first photoelectric conversion unit 20. The first photoelectric conversion unit 20 includes a light absorption layer 4 containing a perovskite compound, an electron transport layer 3 disposed on one side of the light absorption layer 4, and a hole transport layer 5 disposed on the other side of the light absorption layer 4. Have In FIG. 2, the hole transport layer 5 is disposed on the light incident side of the light absorption layer 4. The electron transport layer 3 includes a blocking layer 3a and a porous carrier layer 3b. The details of each layer are as described above.

  Any appropriate photoelectric conversion unit can be adopted as the photoelectric conversion unit (second photoelectric conversion unit 30 in FIG. 2) combined with the perovskite photoelectric conversion unit. In one embodiment, since high efficiency is expected, a photoelectric conversion unit having a narrower band gap than the perovskite photoelectric conversion unit is preferably used. Examples of the photoelectric conversion unit having a narrower band gap than the perovskite photoelectric conversion unit include a silicon-based photoelectric conversion unit (typically, a crystalline silicon-based photoelectric conversion unit). A crystalline silicon-based photoelectric conversion unit typically includes a crystalline silicon substrate, a first conductive layer disposed on one side of the crystalline silicon substrate, and a second conductive layer disposed on the other side of the crystalline silicon substrate. . The conductivity type of the crystalline silicon substrate may be n-type or p-type. The conductivity type of the first conductive layer is different from the conductivity type of the second conductive layer. Specifically, one is p-type and the other is n-type.

  The first conductive layer 32 arranged on the light incident side of the substrate 31 (crystalline silicon substrate) of the second photoelectric conversion unit 30 is a conductive layer (positive electrode) arranged on the light incident side of the first photoelectric conversion unit 20. The second conductive layer 33 having the same conductivity type as the hole transport layer 5) and disposed on the back side of the substrate 31 of the second photoelectric conversion unit 30 is disposed on the back side of the first photoelectric conversion unit 20. And the same conductivity type as the conductive layer (electron transport layer 3). In FIG. 2, the first conductive layer 32 is p-type, and the second conductive layer 33 is n-type. Therefore, the 1st photoelectric conversion unit 20 and the 2nd photoelectric conversion unit 30 are connected in series, and both have the rectification | straightening property of the same direction.

  Specific examples of the crystalline silicon photoelectric conversion unit include a diffusion type silicon photoelectric conversion unit and a heterojunction silicon photoelectric conversion unit. The diffusion type silicon photoelectric conversion unit is obtained, for example, by diffusing doped impurities such as boron and phosphorus on the surface of a crystalline silicon substrate to form a conductive layer (conductive type silicon based semiconductor layer). The heterojunction silicon photoelectric conversion unit can be obtained, for example, by forming a conductive layer by forming a non-single crystal silicon thin film such as amorphous silicon or microcrystalline silicon on a single crystal silicon substrate. Here, a heterojunction is formed between the single crystal silicon substrate and the non-single crystal silicon thin film. The heterojunction silicon photoelectric conversion unit preferably has an intrinsic silicon thin film between the single crystal silicon substrate and the conductive silicon thin film. By having an intrinsic silicon-based thin film, surface passivation can be effectively performed while suppressing diffusion of impurities into the single crystal silicon substrate.

  In one embodiment, the said heterojunction silicon photoelectric conversion unit is employ | adopted for the 2nd photoelectric conversion unit 30 (crystalline silicon type photoelectric conversion unit). In the present embodiment, for example, an n-type single crystal silicon substrate is used as the substrate 31. Although not shown, the substrate 31 may have a texture structure (uneven structure) formed on the surface thereof from the viewpoint of light confinement.

  A p-type silicon-based thin film (first conductive layer 32) is formed on the light incident side of the n-type single-crystal silicon substrate 31 via an intrinsic silicon-based thin film (not shown). On the back side of the substrate 31, an n-type silicon-based thin film (second conductive layer 33) is formed via an intrinsic silicon-based thin film (not shown). Here, the intrinsic silicon thin film is formed by forming an intrinsic amorphous silicon thin film on the surface of the substrate 31 by any appropriate method from the viewpoint of more effectively performing the above-described surface passivation. It is preferable. The thickness of the intrinsic silicon-based thin film is preferably about 2 nm to 15 nm.

  Examples of the material for forming the conductive silicon thin film (conductive layers 32 and 33) include amorphous silicon, microcrystalline silicon (a material containing amorphous silicon and crystalline silicon), an amorphous silicon alloy, A microcrystalline silicon alloy or the like is used. Examples of the silicon alloy include silicon oxide, silicon carbide, silicon nitride, and silicon germanium. Among these, the conductive silicon thin film is preferably an amorphous silicon thin film. The film thickness of the conductive silicon thin film (conductive layers 32 and 33) is preferably about 3 nm to 30 nm.

  The photoelectric conversion element 100 is manufactured by, for example, preparing the second photoelectric conversion unit 30 in advance and sequentially forming each layer constituting the first photoelectric conversion unit 20 on the second photoelectric conversion unit 30. The In one embodiment, between the first photoelectric conversion unit 20 (top cell) and the second photoelectric conversion unit 30 (bottom cell), there is an electrical connection between the two units and incidence for current matching. An intermediate layer (not shown) may be provided for the purpose of adjusting the amount of light. In another embodiment, the bottom layer of the top cell (the electron transport layer 3 in FIG. 2) and / or the top layer of the bottom cell (the first conductive layer 32 in FIG. 2) may have some of the functions of the intermediate layer or You may have everything.

  Although not shown, a transparent electrode layer is formed on the light incident surface of the first photoelectric conversion unit 20 disposed on the light incident side (upper side in the drawing). From the viewpoint of improving the carrier extraction efficiency, for example, a patterned metal electrode may be provided on the surface of the transparent electrode layer. A back electrode is provided on the side opposite to the light incident side (back side) of the second photoelectric conversion unit 30. For example, a transparent electrode layer is formed on the back surface of the second photoelectric conversion unit 30, and a back metal electrode is provided on the transparent electrode layer.

Examples of the material for forming the transparent electrode layer include oxides such as zinc oxide (ZnO), tin oxide (SnO ₂ ), and indium oxide (In ₂ O ₃ ), and composite oxides such as indium tin oxide (ITO). Preferably used. Further, a material obtained by doping W ₂ or Ti into In ₂ O ₃ or SnO ₂ may be used. Since such a transparent conductive oxide has transparency and low resistance, photoexcited carriers can be collected efficiently. As a method for forming the transparent electrode layer, a sputtering method, an MOCVD method, or the like is preferable. In addition to the transparent conductive oxide, fine metal wires such as Ag nanowires and organic materials such as PEDOT-PSS are also used.

  When a metal oxide such as ITO is used as the transparent electrode layer on the light incident side, the photoelectric conversion element has an antireflection film (for example, composed of a low refractive index material such as MgF) on its outermost surface. Is preferred. By having the antireflection film on the outermost surface, the difference in refractive index at the air interface can be reduced, the reflected light can be reduced, and the amount of light taken into the photoelectric conversion element can be increased.

  The back metal electrode may be patterned or planar. For the back electrode, it is desirable to use a material having high reflectivity of long wavelength light and high conductivity and chemical stability. Examples of the material satisfying such characteristics include silver, copper, and aluminum. The back electrode is formed by, for example, a printing method, various physical vapor deposition methods, a plating method, or the like.

  In the first photoelectric conversion unit 20 in the photoelectric conversion element 100, the hole transport layer 5 may be disposed on the opposite side of the light absorption layer 4 from the light incident side. In that case, the first conductive layer 32 of the second photoelectric conversion unit 30 is n-type, and the second conductive layer 33 is p-type.

  The said photoelectric conversion element is modularized by sealing a photoelectric conversion element through a sealing material between a board | substrate and a back sheet, for example. In that case, it may be sealed after connecting a plurality of photoelectric conversion elements in series or in parallel via an interconnect. In the case of only the perovskite type photoelectric conversion unit, by scribe as in the conventional thin film solar cell. By performing integration, the photoelectric conversion elements may be sealed after being connected in series or in parallel. Although each photoelectric conversion element has a high conversion efficiency even though the light absorption layer is continuously formed, the photoelectric conversion elements are connected in series or in parallel. Even in the case of modularization, it is possible to suppress a decrease in the efficiency of the solar cell module due to the photoelectric conversion element exhibiting a small conversion efficiency, and to realize a high module efficiency.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by these Examples. In addition, unless otherwise indicated, the film thickness of each layer in a present Example is the value computed by cross-sectional observation with the scanning electron microscope (Hitachi High-Technologies make, S-4800).

(Example 1 to Example 5)
[FTO substrate processing process]
As the glass substrate 1 and the transparent conductive film 2, five FTO substrates (made by Asahi Glass) having a substrate size of 3 cm × 3 cm and a haze ratio of 13.6% were used. These FTO substrates were ultrasonically washed with ultrapure water, ethanol, and acetone for 10 minutes, respectively, and then dried. Thereafter, the FTO substrate was subjected to surface treatment with UV ozone for 30 minutes.

[Electron transport layer formation process]
On each FTO substrate after UV ozone treatment, compact TiO ₂ was formed to a thickness of 31 nm as the electron transport layer 3 (blocking layer 3a). Specifically, by spraying a mixed solution of 0.3 ml of titanium diisopropoxide bis (acetylacetonate) and 4.0 ml of ethanol solution on the substrate surface heated to 500 ° C. by the spray pyrolysis method. Formed.

Subsequently, a mesoporous TiO ₂ film having a thickness of 200 nm was formed as a metal oxide porous carrier layer 3b on the side of each substrate on which the compact TiO ₂ film was formed. Specifically, titania paste (trade name: 18NR-T, manufactured by Transient Titania Paste Diesol) and ethanol were mixed at a weight ratio of 2: 7, and a dispersion obtained by subjecting this to ultrasonic treatment was mixed. Then, 0.25 ml was dropped on the substrate using a micropipette, spin coating was performed at a speed of 5000 rpm for 30 seconds, and then the substrate was baked in an electric furnace at 500 ° C. for 30 minutes to form an electron transport layer. Five prepared FTO substrates were prepared.

[Light absorption layer forming process]
Subsequently, FA _0.83 MA _0.17 Pb (I _0.83 Br _0.17 ) ₃ is formed as a light absorption layer 4 on the side of the first FTO substrate on which the compact TiO ₂ film is formed to a thickness of 480 nm in a nitrogen atmosphere. did. Specifically, each reagent of PbI ₂ , FAI, MABr, PbBr ₂ was prepared at a molar ratio of 0.83: 0.83: 0.17: 0.17 and mixed at a volume ratio of 4: 1. After adjusting the DMF and DMSO mixed solution to 1.25 mol / L, 0.36 ml of the obtained mixed solution was dropped on the substrate with a micropipette, and spin coating was performed at a speed of 1000 rpm for 10 seconds. While rotating for 20 seconds at a speed of 6000 rpm, chlorobenzene was further dropped with a 0.27 ml micropipette, and then the substrate was baked for 60 minutes at a substrate temperature of 100 ° C., so that the black light absorbing layer 4 was formed. Been formed.

  After the light absorption layer 4 was formed on the FTO substrate on which the first electron transport layer was formed, the atmosphere in which the light absorption layer was formed was replaced with new nitrogen. Then, the light absorption layer was formed with the method mentioned above also with respect to the 2nd FTO board | substrate with which the electron carrying layer was formed. Also for the other three FTO substrates, the light absorption layer 4 was formed by the above-described method after the atmosphere for forming the light absorption layer was replaced with new nitrogen before forming the light absorption layer on each substrate. .

[Hole transport layer formation process]
Subsequently, Spiro-OMeTAD having a thickness of 200 nm was formed as the hole transport layer 5 on the side of each substrate on which FA _0.83 MA _0.17 Pb (I _0.83 Br _0.17 ) ₃ was formed. Specifically, Spiro-OMeTAD, LiTFSi (lithium bis (fluorosulfonyl) imide), tBP (tert-butylpyridine), and Co complex (FK209: manufactured by Diesol) were respectively 70 mmol / L, 35 mmol / L, and 200 mmol / L. Drop 0.18 ml of a chlorobenzene solution containing 2 mmol / L with a micropipette on the substrate, spin coat at a speed of 3000 rpm for 30 seconds, and then fire the substrate at a substrate temperature of 70 ° C. for 30 minutes. Then, the hole transport layer 5 was formed.

[Metal electrode layer forming process]
Thereafter, Au was formed as a metal electrode layer 6 by resistance heating vapor deposition on the side where the hole transport layer was formed on each substrate. In this manner, five perovskite photoelectric conversion elements were produced.

(Comparative Examples 1 to 5)
As shown in Table 1 below, in the light absorption layer formation step, after the light absorption layer is formed, the replacement work with new nitrogen is not performed, and the five light absorption layers are continuously formed. In the same manner as in Examples 1 to 5, perovskite photoelectric conversion elements were produced.

[Evaluation method]
Conversion efficiency (Eff) is measured by irradiating the photoelectric conversion element obtained in each example and each comparative example with light having an illuminance of 100 mW / cm 2 using a solar simulator, and measuring the current-voltage characteristics of each photoelectric conversion element. Was measured. In addition, the photoelectric conversion elements obtained in the respective examples and comparative examples are included in the light absorption layer 4 that can be observed in the vicinity of 2θ = 14 ° by performing X-ray diffraction measurement by the θ-2θ method using CuKα rays. As shown in FIG. 3, the peaks on the (002) plane and the (110) plane derived from perovskite were fitted by the least square method using a pseudo-voit function, and peak separation was performed. The functions and fitting methods used for peak separation can be general ones and are not particularly limited. As the function, for example, a Gaussian function, a Lorentz function, a pseudo-Voit function, and a function obtained by combining a plurality of these functions or other functions can be used. The peak intensity ratio I (110) / I (002) between the peak intensity I (002) on the (002) plane and the peak intensity I (110) on the (110) plane was calculated for the separated peaks. The evaluation results are shown in Table 1.

  From Examples 1 to 5 and Comparative Examples 1 to 5, before forming the light absorbing layer, the light absorbing layer is formed on a plurality of substrates by replacing the formation atmosphere of the light absorbing layer with nitrogen. It can be seen that even when formed continuously, a photoelectric conversion element maintaining high conversion efficiency is manufactured.

1. Transparent substrate 2. Transparent electrode layer Electron transport layer 3a. Blocking layer 3b. 3. Porous carrier layer 4. Light absorption layer Hole transport layer 6. Metal electrode layer 10. Photoelectric conversion element 20. First photoelectric conversion unit 30. Second photoelectric conversion unit 31. Substrate 32. First conductive layer 33. Second conductive layer 100. Photoelectric conversion element

Claims (7)

A light absorption layer containing a perovskite compound, an electron transport layer disposed on one side of the light absorption layer, a hole transport layer disposed on the other side of the light absorption layer, and a transparent electrode layer,
The perovskite compound is
General formula:
ABX ₃
(In the general formula, A is a monovalent cation, B is a divalent metal ion, and X is independently F, Cl, Br, or I.)
Represented by
The perovskite compound has a (002) diffraction peak appearing in the vicinity of 2θ = 13.9 ° and a (110) diffraction peak appearing in the vicinity of 2θ = 14 ° in the X-ray diffraction measurement by the θ-2θ method. (002) The peak intensity ratio I (110) / I (002) between the peak intensity I (002) of the plane and the peak intensity I (110) of the (110) plane is 1.35 to 3.00,
The electron transport layer or the hole transport layer is a solar cell module formed by combining a plurality of photoelectric conversion elements arranged on the transparent electrode layer.   The solar cell module according to claim 1, wherein the peak intensity ratio is 1.50 to 2.00.   The solar cell module according to claim 1 or 2, wherein the transparent electrode layer has a haze ratio of 5% to 20%.   The solar cell module according to claim 3, wherein the haze ratio is 10% to 15%.   The solar cell module according to claim 1, further comprising another photoelectric conversion unit that performs photoelectric conversion.   The solar cell module according to claim 5, wherein the another photoelectric conversion unit includes a crystalline silicon substrate. A plurality of photoelectric conversions having a light absorption layer containing a perovskite compound on a substrate, an electron transport layer disposed on one side of the light absorption layer, and a hole transport layer disposed on the other side of the light absorption layer A method for manufacturing an element, comprising:
In the step of forming a light absorption layer containing a perovskite compound on a plurality of the substrates,
Forming the light absorption layer on the first substrate in an inert gas atmosphere;
Replacing the inert gas with a new inert gas;
Forming the light absorption layer on the second substrate in the new inert gas atmosphere;
Are performed in this order. The manufacturing method of several photoelectric conversion elements.