JP6960233B2 - Solar cell module - Google Patents

Description

The present invention relates to a solar cell module.

A solar cell using a perovskite-type crystal of an organic metal as a light absorption layer (perovskite-type solar cell) can realize high conversion efficiency, and many reports have been made in recent years (for example, Patent Document 1 and non-patent). Document 1). As the organic metal, for example, _{a compound represented by the general formula ABX 3} (in the formula, A is a monovalent cation, B is a divalent metal ion, and X is a halogen) is used. .. Among them, _{perovskite-type crystals such as CH 3} NH ₃ PbX ₃ (X: halogen) can be formed at low cost by, for example, applying a solution such as a spin coating method. Therefore, a perovskite-type solar cell using such a perovskite-type crystal is attracting attention as a low-cost and high-efficiency next-generation solar cell.

Japanese Unexamined Patent Publication No. 2014-72327

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

In a perovskite solar cell, the 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. Industrially, the production of solar cells is carried out continuously. When solar cells with varying conversion efficiencies are connected in series and modularized, the current of the solar cell module is determined by the current of the solar cell showing the smallest current value, and the module efficiency of the solar cell module is lowered. Further, when a plurality of solar cells are connected in parallel and modularized, the voltage of the solar cell module is determined by the voltage of the solar cell showing 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 depends on the solar cell having the lowest characteristics, and the module efficiency is significantly reduced.

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

The solar cell module of the present invention is obtained by connecting a plurality of photoelectric conversion elements in series or in parallel, and each of the plurality of photoelectric conversion elements is a first photoelectric conversion unit between a transparent electrode layer and a metal electrode layer. To be equipped. The first photoelectric conversion unit includes a light absorbing layer containing a perovskite compound, and an electron transporting layer disposed on one side of the light absorbing layer, a hole transport layer disposed on the other side of the light absorbing layer, the The perovskite compound having the above is represented by the general formula: APb X ₃ . A is a monovalent cation, consisting of a methylammonium cation and a formamidinium cation.
X is halogen, comprising Br and I. The perovskite compound has a (002) diffraction peak appearing near 2θ = 13.9 ° and a (110) diffraction peak appearing near 2θ = 14 ° in the X-ray diffraction measurement by the θ-2θ method using CuKα rays. Then, 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 1.35 to 3.00. Oh Ru.

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

In one embodiment, the haze of the transparent electrode layer is between 5% and 20%.

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

In one embodiment, the photoelectric conversion element, between said first photoelectric conversion unit of the metal electrode layer, and a second photoelectric conversion unit having a band gap narrower than said first photoelectric conversion unit ..

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

A perovskite-type photoelectric conversion element including a light absorption layer having a predetermined XRD peak can be continuously manufactured. Further, according to the present invention, it is possible to provide a highly efficient perovskite type solar cell module.

It is a figure which shows typically the cross section of the photoelectric conversion element in one Embodiment of this invention. It is the schematic sectional drawing of the laminated 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-voit function.

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

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

As the transparent substrate 1, a transparent substrate such as glass or a film having a translucent property capable of transmitting light is typically used. As the glass, for example, non-alkali glass can be used. As the film, for example, PET, an aramid film, a 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 laminated film formed by laminating these. 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, more preferably 650 nm to 1000 nm, for example, from the viewpoint of resistivity. The haze rate of the transparent electrode layer is preferably 5% to 20%, more preferably 10% to 15%, for example, from an optical point of view. The haze rate can be measured in accordance with JIS K7136. The transparent electrode layer may be produced by any suitable film-forming method depending on the material for forming the transparent electrode layer. For example, spray pyrolysis is preferable.

The electron transport layer 3 can be formed of any suitable 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 C 61} 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 the donor.

The electron transport layer 3 includes a blocking layer 3a. The blocking layer 3a is a layer capable of suppressing electron transport and reverse electron transfer. The blocking layer is preferably a layer made of a metal oxide such as _{TiO 2 or ZnO, and among them, compact TiO 2} or the like 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, 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 contains a porous carrier layer 3b in addition to the blocking layer 3a. The porous carrier layer 3b is formed on the blocking layer 3a on the side where the light absorption layer 4 is arranged. By providing the porous carrier layer, the coatability 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.

The material for forming the porous carrier layer preferably contains a component contained in the material for forming the blocking layer. This is because the adhesion with the blocking layer can be improved. As a result, it can also contribute to the improvement of the adhesion between the electron transport layer and the light absorption layer. For example, as a material for forming the porous carrier layer, a metal oxide can be used, and it is preferable to use _{porous TiO 2} or Al ₂ O _2. The film thickness of the porous carrier layer is preferably 50 nm to 300 nm, more preferably 100 nm to 200 nm. Within such a range, for example, it can be expected that an optical absorption layer having a perovskite-type crystal structure, which will be described later, can be satisfactorily formed while reducing optical absorption loss.

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

The light absorption layer 4 contains a photosensitive material (perovskite compound) having a perovskite-type crystal structure. The perovskite compound is represented by the _{general formula ABX 3.} In the formula, A is a monovalent cation. Examples of the monovalent cation include monovalent cations such as alkali metal cations and organic cations. More specifically, methylammonium cation (CH ₃ NH ₃ ⁺ ), formamidinium cation (NH ₂ CHNH ₂ ⁺ ), cesium cation (Cs ⁺ ) can be mentioned, and a single cation or a plurality of kinds of cations can be used. It may be mixed. B is a divalent metal ion, and Pb and Sn are preferable. X is a halogen, and examples thereof include F, Cl, Br, and I. The three Xs may all 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 halogens. The light absorption layer 4 has a (002) diffraction peak appearing near 2θ = 13.9 ° and a (110) diffraction peak appearing near 2θ = 14 ° in the X-ray diffraction measurement by the θ-2θ method using CuKα rays. Then, 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. By doing so, a highly efficient perovskite type 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, and more preferably 200 nm to 500 nm from the viewpoint of light absorption efficiency and exciton diffusion length, for example.

The light absorption layer containing the perovskite compound can be formed on the substrate by a dry process or a wet process, similarly to the electron transport layer described above. These processes are carried out in a sealed atmosphere such as a glove box in an atmosphere of an inert gas such as argon or nitrogen. The light absorption layer containing the 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 adopted 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 spun. _{CH 3} NH ₃ PbI ₃ crystals can be grown by applying by 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. When forming a plurality of light absorbing layers in succession, if a solvent such as dimethyl sulfoxide or N, N-dimethylformamide is excessively present in the forming atmosphere of the light absorbing layer, it inhibits the formation of the perovskite compound. Before forming the light absorption layer of each photoelectric conversion element, the formation atmosphere of the light absorption layer is replaced with a new inert gas such as argon or nitrogen. The replacement work with the new inert gas does not have to be carried out every time before the formation of the light absorption layer, and after the plurality of light absorption layers are formed without the replacement work of the inert gas, a new work is performed. Substitution work with an inert gas may be performed, followed by the formation of a plurality of light absorbing layers. Further, when a large-area light absorption layer such as roll-to-roll is formed at one time, the work of replacing the forming atmosphere of the light absorption layer with a new inert gas is appropriately performed.

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, CH 3} NH ₃ PbI ₃ crystals can be obtained by forming a thin film of lead iodide by a vacuum vapor deposition method and contacting the surface with an isopropyl alcohol solution of methylammonium iodide. Examples of the method of bringing the solution into contact with the surface of the vapor-deposited film include a method of applying the solution by spin coating and the like, and a method of immersing the vapor-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 immersion method is preferably used from the viewpoint of uniform contact with the solution.

For the hole transport layer 5, conventionally known materials may be appropriately selected. 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'-fluorene derivatives such as spirobifluorene (Spiro-OMeTAD), carbazole derivatives such as polyvinylcarbazole, Examples thereof include triphenylamine derivatives, diphenylamine derivatives, polysilane derivatives, polyaniline derivatives and the like. Further, examples of the material of the hole transport layer include metal oxides such as _{MoO 3} , WO _{3, and NiO.}

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, for example, a solution containing a hole transport material such as Spiro-OMeTAD described above.

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

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

FIG. 2 is a schematic cross-sectional view of a laminated photoelectric conversion element according to an embodiment of the present invention. The photoelectric conversion element 100 has 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 figure).

As one of the photoelectric conversion units constituting the laminated photoelectric conversion element, a perovskite type photoelectric conversion unit having a light absorption layer containing the perovskite compound is adopted. In FIG. 2, a perovskite type photoelectric conversion unit is adopted 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 arranged on one side of the light absorption layer 4, and a hole transport layer 5 arranged on the other side of the light absorption layer 4. Has. In FIG. 2, the hole transport layer 5 is arranged 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 suitable photoelectric conversion unit may be adopted as the photoelectric conversion unit (second photoelectric conversion unit 30 in FIG. 2) to be combined with the perovskite type photoelectric conversion unit. In one embodiment, since high efficiency is expected, a photoelectric conversion unit having a narrower bandgap than the perovskite type photoelectric conversion unit is preferably used. Examples of the photoelectric conversion unit having a narrower bandgap than the perovskite type 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 has a crystalline silicon substrate, a first conductive layer arranged on one side of the crystalline silicon substrate, and a second conductive layer arranged on the other side of the crystalline silicon substrate. .. The conductive type of the crystalline silicon substrate may be n type or p type. The conductive type of the first conductive layer and the conductive type of the second conductive layer are different. 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) arranged on the light incident side of the first photoelectric conversion unit 20. The second conductive layer 33, which has the same conductive type as the hole transport layer 5) and is arranged on the back side of the substrate 31 of the second photoelectric conversion unit 30, is arranged on the back side of the first photoelectric conversion unit 20. It has the same conductive 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 first photoelectric conversion unit 20 and the second photoelectric conversion unit 30 are connected in series, and both have rectification in the same direction.

Specific examples of the crystalline silicon-based 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 doping impurities such as boron and phosphorus on the surface of a crystalline silicon substrate to form a conductive layer (conductive 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-based 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-based thin film between the single crystal silicon substrate and the conductive silicon-based thin film. By having the intrinsic silicon-based thin film, surface passivation can be effectively performed while suppressing the diffusion of impurities into the single crystal silicon substrate.

In one embodiment, the heterojunction silicon photoelectric conversion unit is adopted as the second photoelectric conversion unit 30 (crystal silicon-based photoelectric conversion unit). In this 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 (concave and convex structure) formed on its surface from the viewpoint of light confinement and the like.

A p-type silicon 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 thin film (not shown), and n-type single crystal silicon. An n-type silicon thin film (second conductive layer 33) is formed on the back side of the substrate 31 via an intrinsic silicon 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 an arbitrary appropriate method from the viewpoint of more effectively performing the above-mentioned surface passivation. Is preferable. The film 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-based thin film (conductive layers 32 and 33) include amorphous silicon, microcrystalline silicon (material containing amorphous silicon and crystalline silicon), amorphous silicon alloy, and the like. A microcrystalline silicon alloy or the like is used. Examples of the silicon alloy include silicon oxide, silicon carbide, silicon nitride, silicon germanium and the like. Among these, the conductive silicon-based thin film is preferably an amorphous silicon thin film. The film thickness of the conductive silicon-based thin film (conductive layers 32 and 33) is preferably about 3 nm to 30 nm.

The photoelectric conversion element 100 is manufactured, for example, by manufacturing a 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. NS. In one embodiment, the first photoelectric conversion unit 20 (top cell) and the second photoelectric conversion unit 30 (bottom cell) are electrically connected to each other and incident for current matching. An intermediate layer (not shown) may be provided for the purpose of adjusting the amount of light or the like. In another embodiment, the bottom layer of the top cell (electron transport layer 3 in FIG. 2) and / or the top layer of the bottom cell (first conductive layer 32 in FIG. 2) is a part of the function of the intermediate layer or You may have all of them.

Although not shown, a transparent electrode layer is formed on the light incident surface of the first photoelectric conversion unit 20 arranged on the light incident side (upper side of the figure). 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 surface electrode is provided on the side (back side) opposite to the light incident 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 surface 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). It is preferably used. Further, _{a material obtained by doping In 2} O ₃ or Sn _{O 2} with W, Ti or the like may be used. Since such a transparent conductive oxide has transparency and low resistance, photoexcited carriers can be efficiently collected. As a film forming method for the transparent electrode layer, a sputtering method, a 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 preferable. By having the antireflection film on the outermost surface, it is possible to reduce the difference in refractive index at the air interface, reduce the reflected light, and increase the amount of light taken into the photoelectric conversion element.

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

Further, in the first photoelectric conversion unit 20 of the photoelectric conversion element 100, the hole transport layer 5 may be arranged on the side opposite to the light incident side of the light absorption layer 4. 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 photoelectric conversion element is modularized by, for example, sealing the photoelectric conversion element between a substrate and a back sheet via a sealing material. In that case, a plurality of photoelectric conversion elements may be connected in series or in parallel via an interconnect and then sealed. In the case of only the perovskite type photoelectric conversion unit, a scribe is used as in the conventional thin film solar cell. By integrating, the photoelectric conversion elements may be connected in series or in parallel and then sealed. Although each photoelectric conversion element has a high conversion efficiency even though the light absorption layer is continuously formed in the photoelectric conversion element, the photoelectric conversion elements are connected in series or in parallel. Even when modularized, 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 it is possible to realize high module efficiency.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. The thickness of each layer in this example is a value calculated by cross-sectional observation with a scanning electron microscope (manufactured by Hitachi High-Technologies Corporation, S-4800) unless otherwise specified.

(Examples 1 to 5)
[FTO substrate processing process]
As the glass substrate 1 and the transparent conductive film 2, five FTO substrates (manufactured by Asahi Glass) having a substrate size of 3 cm × 3 cm and a haze rate of 13.6% were used. These FTO substrates were ultrasonically cleaned with ultrapure water, ethanol, and acetone for 10 minutes each, and then dried. Then, the FTO substrate was surface-treated with UV ozone for 30 minutes.

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

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

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

After forming the light absorption layer 4 on the FTO substrate on which the first electron transport layer was formed, the formation atmosphere of the light absorption layer was replaced with new nitrogen. Subsequently, a light absorption layer was also formed on the second FTO substrate on which the electron transport layer was formed by the method described above. For the other three FTO substrates, the light absorption layer 4 was formed by the method described above after replacing the formation atmosphere of the light absorption layer with new nitrogen before forming the light absorption layer on each substrate. ..

[Hole transport layer forming process]
Subsequently, Spiro-OMeTAD was formed with a film thickness of 200 nm 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 pipette) are 70 mmol / L, 35 mmol / L, and 200 mmol / L, respectively. 0.18 ml of a chlorobenzene solution containing a concentration of 2 mmol / L is dropped onto the substrate with a micropipette, spin coating is performed at a rate of 3000 rpm for 30 seconds, and then the substrate is baked at a substrate temperature of 70 ° C. for 30 minutes. The hole transport layer 5 was formed in.

[Metal electrode layer forming process]
Then, Au was formed as a metal electrode layer 6 on the side where the hole transport layer was formed on each substrate by resistance heating vapor deposition at a film thickness of 200 nm. In this way, five perovskite-type photoelectric conversion elements were produced.

(Comparative Examples 1 to 5)
As shown in Table 1 below, in the light absorption layer forming step, five consecutive light absorption layers were formed without performing replacement work with new nitrogen after the formation of the light absorption layer. In the same manner as in Examples 1 to 5, a perovskite-type photoelectric conversion element was produced.

[Evaluation method]
Using a solar simulator, ^{light with an illuminance of 100 mW / cm 2} is applied to the photoelectric conversion elements obtained in each Example and each Comparative Example, and the current-voltage characteristics of each photoelectric conversion element are measured to obtain conversion efficiency (Eff). ) Was measured. Further, the photoelectric conversion elements obtained in each Example and each Comparative Example are subjected to X-ray diffraction measurement by the θ-2θ method using CuKα rays, and are included in the light absorption layer 4 that can be observed in the vicinity of 2θ = 14 °. As shown in FIG. 3, the peaks of the (002) plane and the (110) plane derived from perovskite were fitted by the least squares method by a pseudo-voit function, and peak separation was performed . Was calculated peak intensity ratio I minute apart were respect peak (002) plane peak of intensity I (002) and (110) peak intensity of the plane I (110) (110) / I (002). The evaluation results are shown in Table 1.

From Examples 1 to 5 and from Comparative Examples 1 to 5, the light absorption layer was formed on a plurality of substrates by substituting the formation atmosphere of the light absorption layer with nitrogen before the formation of the light absorption layer. It can be seen that a photoelectric conversion element that maintains high conversion efficiency even when it is continuously formed is manufactured.

1. 1. Transparent substrate 2. Transparent electrode layer 3. Electron transport layer 3a. Blocking layer 3b. Porous carrier layer 4. Light absorption layer 5. 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 (6)

A solar cell module in which multiple photoelectric conversion elements are connected in series or in parallel.
Each of the plurality of photoelectric conversion elements includes a first photoelectric conversion unit between the transparent electrode layer and the metal electrode layer.
Said first photoelectric conversion unit includes a light absorbing layer containing a perovskite compound, and an electron transporting layer disposed on one side of the light absorbing layer, a hole transport layer disposed on the other side of the light absorbing layer, the Have and
The perovskite compound has the general formula: represented by A Pb _{X 3,}
A is a monovalent cation, consisting of a methylammonium cation and a formamidinium cation.
X is a halogen, consisting of Br and I ,
The perovskite compound has a (002) diffraction peak appearing near 2θ = 13.9 ° and a (110) diffraction peak appearing near 2θ = 14 ° in the X-ray diffraction measurement by the θ-2θ method using CuKα rays. Then, 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 1.35 to 3.00. Oh Ru,
Solar cell module. 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 haze rate of the transparent electrode layer is 5% to 20%. The solar cell module according to claim 3, wherein the haze rate is 10% to 15%. Claims 1 to 4 include the photoelectric conversion element having a second photoelectric conversion unit having a band gap narrower than that of the first photoelectric conversion unit between the first photoelectric conversion unit and the metal electrode layer. The solar cell module described in any of. The solar cell module according to claim 5, wherein the second photoelectric conversion unit includes a crystalline silicon substrate.

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