Solar cell and method for manufacturing solar cell

Abstract

To improve the durability of solar cells.SOLUTION: A solar cell 1000 according to the present disclosure includes a support material 2, a photoelectric converter 1, and a sealing material 3. The photoelectric converter 1 is arranged in a sealed space sealed by the support material 2 and the sealing material 3. The photoelectric converter 1 sequentially includes a first electrode, a photoelectric conversion layer, and a second electrode. The value obtained by dividing the oxygen amount in the sealed space by the surface area of the surface facing the sealed space of the photoelectric converter is at least 2.3×10-7 mol / m2 and is 7.0×10-5 mol / m2 at a maximum.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a solar cell and a method for manufacturing the same.

Background Art

[0002] In recent years, research and development of perovskite solar cells using a perovskite-type crystal represented by a compositional formula ABX3 (where A is a monovalent cation, B is a divalent cation, and X is a halogen anion) and a similar structure (hereinafter referred to as a "perovskite compound") as a photoelectric conversion material has been advanced. Various efforts have been made to improve the photoelectric conversion efficiency and durability of perovskite solar cells.

[0003] In Non-Patent Document 1, it is reported that oxygen reacts with cations in a perovskite compound under light irradiation, and thereby metal oxides or hydroxides are formed on the surface or grain boundaries of the perovskite compound.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Non-Patent Documents

[0005]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] An object of the present disclosure is to improve the durability of a solar cell.

Means for Solving the Problems

[0007] The solar cell of the present disclosure has a support member, a photoelectric conversion element, and a sealing material, and the photoelectric conversion element is disposed inside a sealed space sealed by the support member and the sealing material, the photoelectric conversion element includes a first electrode, a photoelectric conversion layer, and a second electrode, in this order, the value obtained by dividing the amount of oxygen in the sealed space by the surface area of the surface of the photoelectric conversion element facing the sealed space is 2.3×10 -7 mol / m 2 or more and 7.0×10 -5 mol / m 2 or less.

Advantages of the Invention

[0008] The present disclosure can improve the durability of the solar cell.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0010] <Findings on which the Present Disclosure is Based> As reported in Non-Patent Document 1, perovskite compounds containing lead react with oxygen under light irradiation to form lead oxide (PbO) or lead hydroxide (Pb(OH)2) on the surface or grain boundaries of the perovskite compound. When a large amount of these highly insulating reaction products are formed, the movement of photo-generated carriers is inhibited, resulting in a problem that the characteristics of perovskite solar cells deteriorate. For this reason, generally, perovskite solar cells are used in a nitrogen atmosphere with as little oxygen as possible (for example, an oxygen concentration of 0.1 ppm or less by volume fraction). In this specification, all oxygen concentrations described below mean concentrations by volume fraction.

[0011] In Non-Patent Document 1, it is disclosed that the normalized photoelectric conversion efficiency after the light irradiation test of a perovskite solar cell monotonically decreases as the oxygen concentration increases from 1% to 20% based on the case where the oxygen concentration around the solar cell is 0%.

[0012] Patent Document 1 discloses a configuration including oxygen and moisture in a sealed space in a perovskite solar cell having a sealing structure. It is disclosed that by controlling the oxygen concentration in the space to 5% or more and the moisture concentration (volume fraction) to 300 ppm or less, the heat resistance of the solar cell is improved. Here, since the oxidized form of the hole transport material is reduced by moisture, it is disclosed that the moisture concentration needs to be controlled within the above range.

[0013] However, Non-Patent Document 1 reports that the light resistance decreases when the oxygen concentration is 5%. Therefore, it is predicted that the durability of the solar cell is not sufficient in the range where the oxygen concentration is 5% or more.

[0014] In Patent Document 1, data in the range where the oxygen concentration is less than 2% are not disclosed.

[0015] In view of these prior arts, the inventors have investigated in detail the oxygen concentration that significantly affects durability. As a result, it has been found that there is an oxygen concentration optimal for the durability of a solar cell within a specific range where the oxygen concentration is less than 2% by volume fraction. Specifically, in a solar cell having a sealing structure, when the oxygen concentration in the sealed space is in the range of 10 ppm or more and 3000 ppm or less, the photoelectric conversion efficiency after a light irradiation test is improved. Further, when the oxygen concentration in the sealed space is in the range of 100 ppm or more and 3000 ppm or less, the photoelectric conversion efficiency after a heat resistance test is also improved.

[0016] <Embodiment of the present disclosure> The solar cell according to an embodiment of the present disclosure includes a support material, a photoelectric conversion element, and a sealing material, and the photoelectric conversion element is disposed inside a sealed space sealed by the support material and the sealing material. The photoelectric conversion element includes a first electrode, a photoelectric conversion layer, and a second electrode in this order. The oxygen concentration in the sealed space is 10 ppm or more and 3000 ppm or less.

[0017] According to the above configuration, the photo-degradation phenomenon induced by defects in the photoelectric conversion material can be suppressed. Therefore, the durability of the solar cell can be improved.

[0018] In the solar cell according to this embodiment, the oxygen concentration in the sealed space may be 100 ppm or more and 3000 ppm or less.

[0019] According to the above configuration, since the defects in the photoelectric conversion material can be sufficiently terminated, the structural change of the photoelectric conversion material induced by heat is less likely to occur, and the thermal stability of the solar cell can be enhanced. Therefore, according to the above configuration, it is possible to achieve both the optical stability and the thermal stability of the solar cell. That is, according to the above configuration, the durability of the solar cell can be further improved.

[0020] The measurement of the oxygen concentration in the sealed space can be carried out by an atmospheric pressure ionization mass spectrometer, gas chromatography, an electrochemical oxygen concentration meter, etc. The gas to be measured for oxygen concentration can, for example, at room temperature (25 °C), extract the gas in the sealed space with a syringe, or break the solar cell module in a closed space to let the gas contained in the sealed space flow out, measure the components of the gas, and calculate the proportion of oxygen, thereby obtaining the oxygen concentration. Here, as an example, a method of letting the gas contained in the sealed space of a solar cell flow out in a closed space and measuring the oxygen concentration in the outflowed gas with an atmospheric pressure ionization mass spectrometer will be described. For example, place the solar cell module in a chamber filled with an inert gas such as argon or krypton. By damaging the module in the chamber, the gas contained in the sealed space of the solar cell is allowed to flow out. Next, quantitatively analyze the gas in the chamber with an atmospheric pressure ionization mass spectrometer. By quantifying all the components in the gas in the chamber and calculating the proportion of oxygen in the total amount, the oxygen concentration can be obtained. Gases other than oxygen contained in the sealed space include inert gases such as nitrogen and noble gases, carbon dioxide, and water vapor. Note that if the same type of inert gas that fills the chamber used for gas analysis is contained in the sealed space, accurate gas analysis may be difficult. Therefore, when the type of gas contained in the sealed space is unknown, prepare two identical solar cell modules, and use different types of inert gases as the inert gases that fill the chamber, and perform gas analysis on the two solar cell modules according to the above procedure respectively. By comparing the two analysis results, the composition of the gas contained in the sealed space can be obtained.

[0021] The partial pressure of oxygen in the sealed space is 1×10 -5 atm or more and 3×10 -3 atm or less may be sufficient.

[0022] According to the above configuration, it becomes easier to suppress the photo-degradation phenomenon induced by the defects of the photoelectric conversion material. Therefore, the durability of the solar cell can be improved. When manufacturing the solar cell of the present disclosure under atmospheric pressure, the pressure in the sealed space becomes about atmospheric pressure. In this case, the partial pressure of oxygen in the sealed space is 1×10 -5 atm or more and 3×10 -3 atm or less.

[0023] The partial pressure of oxygen in the sealed space can be calculated from the equation of state of the gas by, for example, measuring the mass or molar concentration of the gas containing oxygen in the sealed space using the above-described method for measuring the oxygen concentration, and further measuring the volume of the sealed space. The volume of the sealed space can be measured, in addition to dimensioning, for example, by evacuating the inside of the sealed space and then injecting an inert gas with a known pressure and volume into the sealed space to obtain the volume from the pressure change, or by injecting a liquid with a known density into the sealed space and obtaining the volume from the weight change. The above-described various measurements are usually performed at room temperature, but this is not always the case. That is, in order to consider the adsorption and desorption of the gas in the sealed space, it may also be possible to perform the measurements at a temperature assuming the actual operating environment.

[0024] A modified example of the solar cell according to an embodiment of the present disclosure will be described. Redundant explanations may be omitted as appropriate.

[0025] As described above, the solar cell of the present disclosure includes a support material, a photoelectric conversion element, and a sealing material, and the photoelectric conversion element is disposed inside a sealed space sealed by the support material and the sealing material. The photoelectric conversion element includes a first electrode, a photoelectric conversion layer, and a second electrode in this order. The amount of oxygen in the sealed space per unit surface area of the surface of the photoelectric conversion element facing the sealed space is 2.3×10 -7 mol / m 2 or more and 7.0×10 -5 mol / m 2 or less. That is, the value obtained by dividing the amount of oxygen in the sealed space by the surface area of the surface of the photoelectric conversion element facing the sealed space is 2.3×10 -7 mol / m 2 or more and 7.0×10 -5 mol / m 2 or less. Thereby, deterioration due to the long-term operation of the solar cell can be suppressed.

[0026] In the photoelectric conversion element, the main surface of the first electrode may face the support material, or the main surface of the second electrode may face the support material.

[0027] The solar cell of the present disclosure can be manufactured, for example, by the following method. First, a photoelectric conversion element is manufactured by the method described later.

[0028] The obtained photoelectric conversion element is sealed with a sealing material in a glove box in which the oxygen concentration is adjusted.

[0029] The oxygen concentration in the glove box is 10 ppm or more and 3000 ppm or less. Alternatively, the oxygen concentration in the glove box is such that the amount of oxygen in the sealing space per surface area of the surface facing the sealing space of the photoelectric conversion element is 2.3×10 -7 mol / m 2 or more and 7.0×10 -5 mol / m 2 or less.

[0030] The pressure and oxygen concentration in the glove box are controlled so that the partial pressure of oxygen in the sealing space is 1×10 -5 atm or more and 3×10 -3 atm or less.

[0031] As described above, a solar cell having a desired oxygen concentration, oxygen amount, or oxygen partial pressure can be obtained.

[0032] As described above, a solar cell may be manufactured by sealing a photoelectric conversion element including a first electrode, a photoelectric conversion layer, and a second electrode in this order in an atmosphere having an oxygen concentration of 10 ppm or more and 3000 ppm or less by volume fraction.

[0033] FIG. 1 is a diagram showing a schematic configuration of a solar cell 1000 according to an embodiment of the present disclosure.

[0034] The solar cell 1000 according to this embodiment includes a photoelectric conversion element 1, a support member 2, and a sealing material 3. The photoelectric conversion element 1 is disposed inside a sealed space sealed by the support member 2 and the sealing material 3.

[0035] The photoelectric conversion element 1 may be in contact with the support member 2.

[0036] The support member 2 and the sealing material 3 may be made of the same material. The material may have, for example, a gas barrier function. The material may be glass.

[0037] Hereinafter, the photoelectric conversion element 1 will be described more specifically using the first to third configuration examples. Note that the photoelectric conversion element 1 is not limited to the photoelectric conversion elements of the following first to third configuration examples.

[0038] FIG. 2 is a cross-sectional view showing a schematic configuration of a first configuration example of the photoelectric conversion element 1 in the solar cell 1000 according to an embodiment of the present disclosure.

[0039] The photoelectric conversion element 100 of the first configuration example includes a substrate 4, a first electrode 5, an electron transport layer 6, a photoelectric conversion layer 7, a hole transport layer 8, and a second electrode 9 in this order. Like the photoelectric conversion element 100 of the first configuration example, the photoelectric conversion element 1 in the solar cell 1000 according to this embodiment may further include an electron transport layer between the first electrode and the photoelectric conversion layer, or may further include a hole transport layer between the photoelectric conversion layer and the second electrode.

[0040] When light is irradiated on the photoelectric conversion element 100, the photoelectric conversion layer 7 absorbs the light and generates excited electrons and holes. These excited electrons move through the electron transport layer 6 to the first electrode 5. On the other hand, the holes generated in the photoelectric conversion layer 7 move to the second electrode 9 through the hole transport layer 8. Thereby, the photoelectric conversion element 100 can extract current from the first electrode 5 as a negative electrode and the second electrode 9 as a positive electrode.

[0041] The photoelectric conversion element 100 may or may not have a substrate 4.

[0042] The photoelectric conversion element 100 may or may not have an electron transport layer 6. When the photoelectric conversion element 100 has the electron transport layer 6, electrons can be efficiently moved to the first electrode 5. As a result, the photoelectric conversion element 100 can efficiently extract current.

[0043] The photoelectric conversion element 100 may or may not have a hole transport layer 8. When the photoelectric conversion element 100 has the hole transport layer 8, holes can be efficiently moved to the second electrode 9. As a result, the photoelectric conversion element 100 can efficiently extract current.

[0044] The photoelectric conversion element 100 can be manufactured, for example, by the following method.

[0045] First, the first electrode 5 is formed on the surface of the substrate 4 by chemical vapor deposition, sputtering, or the like. Next, the electron transport layer 6 is formed by chemical vapor deposition, sputtering, solution coating, or the like. Next, a photoelectric conversion layer 7 is formed on the electron transport layer 6. The photoelectric conversion layer 7 may be formed, for example, by a coating method using a solution, a printing method, or a vapor deposition method. Further, for example, a perovskite compound cut to a predetermined thickness may be used as the photoelectric conversion layer 7 and disposed on the electron transport layer 6. Next, the hole transport layer 8 is formed on the photoelectric conversion layer 7 by chemical vapor deposition, sputtering, solution coating, or the like. Next, the second electrode 9 is formed on the hole transport layer 8 by chemical vapor deposition, sputtering, solution coating, or the like. Thus, the photoelectric conversion element 100 is obtained.

[0046] FIG. 3 is a cross-sectional view showing a schematic configuration of a second configuration example of the photoelectric conversion element 1 in the solar cell 1000 according to an embodiment of the present disclosure.

[0047] The photoelectric conversion element 200 includes a substrate 4, a first electrode 5, an electron transport layer 6, a porous layer 10, a photoelectric conversion layer 7, a hole transport layer 8, and a second electrode 9 in this order. Like the photoelectric conversion element 200 of the second configuration example, the photoelectric conversion element 1 in the solar cell 1000 according to this embodiment may further include a porous layer. The porous layer is disposed, for example, between the electron transport layer and the photoelectric conversion layer.

[0048] The porous layer 10 includes a porous body. The porous body includes voids.

[0049] The photoelectric conversion element 200 may or may not have a substrate 4.

[0050] The photoelectric conversion element 200 may or may not have an electron transport layer 6. When the photoelectric conversion element 200 does not have the electron transport layer 6, the porous layer 10 is disposed between the first electrode 5 and the photoelectric conversion layer 7. When the photoelectric conversion element 200 has the electron transport layer 6, electrons can be efficiently moved to the first electrode 5. As a result, the photoelectric conversion element 200 can efficiently extract current.

[0051] The photoelectric conversion element 200 may or may not have a hole transport layer 8. When the photoelectric conversion element 200 has the hole transport layer 8, holes can be efficiently moved to the second electrode 9. As a result, the photoelectric conversion element 200 can efficiently extract current.

[0052] FIG. 4 is a cross-sectional view showing a schematic configuration of a third configuration example of the photoelectric conversion element 1 in the solar cell 1000 according to an embodiment of the present disclosure.

[0053] The photoelectric conversion element 300 of the third configuration example includes a substrate 4, a first electrode 5, an electron transport layer 6, a porous layer 10, an intermediate layer 11, a photoelectric conversion layer 7, a hole transport layer 8, and a second electrode 9 in this order. Like the photoelectric conversion element 300 of the third configuration example, the photoelectric conversion element 1 in the solar cell 1000 according to this embodiment may further include an intermediate layer. The intermediate layer is disposed, for example, between the porous layer and the photoelectric conversion layer.

[0054] The photoelectric conversion element 300 may or may not have a substrate 4.

[0055] The photoelectric conversion element 300 may or may not have an electron transport layer 6. When the photoelectric conversion element 300 has an electron transport layer 6, electrons can be efficiently moved to the first electrode 5. As a result, the photoelectric conversion element 300 can efficiently extract current.

[0056] The photoelectric conversion element 300 may or may not have a hole transport layer 8. When the photoelectric conversion element 300 has a hole transport layer 8, holes can be efficiently moved to the second electrode 9. As a result, the photoelectric conversion element 300 can efficiently extract current.

[0057] The photoelectric conversion element 300 may or may not have a porous layer 10. When the photoelectric conversion element 300 does not have a porous layer 10, the intermediate layer 11 is disposed between the electron transport layer 6 and the photoelectric conversion layer 7.

[0058] Hereinafter, each component of the photoelectric conversion element will be specifically described.

[0059] (Substrate 4) The substrate 4 is an incidental component. The substrate 4 serves to hold each layer of the photoelectric conversion element. The substrate 4 can be formed from a transparent material. As the substrate 4, for example, a glass substrate or a plastic substrate can be used. The plastic substrate may be, for example, a plastic film.

[0060] When the second electrode 9 has translucency, the substrate 4 may be formed from a material that does not have translucency. As such a material, a metal, ceramics, or a resin material with low translucency can be used.

[0061] When the first electrode 5 has sufficient strength, each layer can be held by the first electrode 5, so the substrate 4 may not be provided.

[0062] (The first electrode 5) The first electrode 5 has conductivity.

[0063] The first electrode 5 has light transmittance. For example, it transmits light from the visible region to the near-infrared region.

[0064] The first electrode 5 is composed of, for example, a material that is transparent and has conductivity. Examples of such materials are metal oxides or metal nitrides. Examples of such materials are (i) titanium oxide doped with at least one selected from the group consisting of lithium, magnesium, niobium, and fluorine, (ii) gallium oxide doped with at least one selected from the group consisting of tin and silicon, (iii) gallium nitride doped with at least one selected from the group consisting of silicon and oxygen, (iv) tin oxide doped with at least one selected from the group consisting of antimony and fluorine, (v) zinc oxide doped with at least one selected from the group consisting of boron, aluminum, gallium, and indium, (vi) indium-tin composite oxide, or (vii) these composites, are.

[0065] The first electrode 5 may be formed by providing a pattern through which light can pass. Examples of the pattern through which light can pass include a linear shape, a wavy shape, a grid shape, or a punching metal-like pattern in which a large number of fine through-holes are arranged regularly or irregularly. When the first electrode 5 has these patterns, light can pass through the portions where the electrode material does not exist. Therefore, by providing a pattern through which light can pass, a non-transparent material can be used. Examples of non-transparent electrode materials include platinum, gold, silver, copper, aluminum, rhodium, indium, titanium, iron, nickel, tin, zinc, or an alloy containing any of these. A conductive carbon material may be used as the non-transparent electrode material.

[0066] When the photoelectric conversion element does not include the electron transport layer 6, the first electrode 5 has blocking properties against holes from the photoelectric conversion layer 7. In this case, the first electrode 5 does not have an ohmic contact with the photoelectric conversion layer 7. Further, the blocking property against holes from the photoelectric conversion layer 7 means a property of allowing only electrons generated in the photoelectric conversion layer 7 to pass through and not allowing holes to pass through. The Fermi energy of a material having such a property is higher than the energy at the upper end of the valence band of the photoelectric conversion layer 7. The Fermi energy of a material having such a property may be higher than the Fermi energy of the photoelectric conversion layer 7. As a specific material, aluminum can be mentioned.

[0067] When the photoelectric conversion element includes the electron transport layer 6, the first electrode 5 may not have blocking properties against holes from the photoelectric conversion layer 7. In this case, the first electrode 5 can be composed of a material capable of forming an ohmic contact with the photoelectric conversion layer 7. In this case, the first electrode 5 may or may not have an ohmic contact with the photoelectric conversion layer 7.

[0068] The light transmittance of the first electrode 5 may be, for example, 50% or more, or may be 80% or more. The wavelength of the light that the first electrode 5 should transmit depends on the absorption wavelength of the photoelectric conversion layer 7.

[0069] The thickness of the first electrode 5 may be, for example, 1 nm or more and 1000 nm or less.

[0070] (Electron transport layer 6) The electron transport layer 6 contains a semiconductor. The electron transport layer 6 may be formed of a semiconductor having a band gap of 3.0 eV or more. Thereby, visible light and infrared light can be transmitted to the photoelectric conversion layer 7. Examples of the semiconductor are inorganic n-type semiconductors.

[0071] Examples of inorganic n-type semiconductors are metal oxides, metal nitrides, or perovskite-type oxides. Examples of metal oxides are oxides of Cd, Zn, In, Pb, Mo, W, Sb, Bi, Cu, Hg, Ti, Ag, Mn, Fe, V, Sn, Zr, Sr, Ga, Si, or Cr. The metal oxide is, for example, TiO2 or SnO2. The metal nitride is, for example, GaN. The perovskite-type oxide is, for example, SrTiO3 or CaTiO3.

[0072] The electron transport layer 6 may contain a substance having a band gap larger than 6.0 eV. Examples of such substances are (i) halides of alkali metals or alkaline earth metals such as lithium fluoride and calcium fluoride, (ii) alkali metal oxides such as magnesium oxide, or (iii) silicon dioxide, and so on. In this case, the electron transport layer 6 may have a thickness of, for example, 10 nm or less in order to ensure electron transport properties.

[0073] The electron transport layer 6 may include a plurality of layers made of different materials from each other.

[0074] (Photoelectric conversion layer 7) The photoelectric conversion layer 7 contains a photoelectric conversion material.

[0075] The photoelectric conversion material may be, for example, a perovskite compound. That is, the photoelectric conversion layer 7 may contain a perovskite compound. The perovskite compound has a high light absorption coefficient in the wavelength range of the solar spectrum and a high carrier mobility. Therefore, a photoelectric conversion element containing a perovskite compound has a high photoelectric conversion efficiency.

[0076] The perovskite compound is represented by, for example, the composition formula ABX3. A is a monovalent cation. Examples of monovalent cations are alkali metal cations or organic cations. Examples of alkali metal cations are potassium cation (K + ), cesium cation (Cs + ), or rubidium cation (Rb + ). Examples of organic cations are methylammonium cation (MA + or CH3NH3 + ), formamidinium cation (FA + or HC(NH2)2 + ), ethylammonium cation (CH3CH2NH3 + ), or guanidinium cation (CH6N3 + ). B is a divalent cation. Examples of divalent cations are lead cation (Pb 2+ ) or tin cation (Sn 2+ ). X is a monovalent anion. Examples of monovalent anions are halogen anions. Each site of A, B, and X may be occupied by multiple types of ions.

[0077] The photoelectric conversion material may be, for example, a perovskite compound containing lead.

[0078] The thickness of the photoelectric conversion layer 7 is, for example, 50 nm or more and 10 μm or less.

[0079] The photoelectric conversion layer 7 is formed, for example, by a coating method using a solution, a printing method, or a vapor deposition method. The photoelectric conversion layer 7 may also be formed by cutting out and arranging a perovskite compound.

[0080] The photoelectric conversion layer 7 may mainly contain a perovskite compound represented by the composition formula ABX3. Here, "the photoelectric conversion layer 7 mainly contains a perovskite compound represented by the composition formula ABX3" means that the photoelectric conversion layer 7 contains 90% by mass or more of the perovskite compound represented by the composition formula ABX3. The photoelectric conversion layer 7 may contain 95% by mass or more of the perovskite compound represented by the composition formula ABX3. The photoelectric conversion layer 7 may be composed of a perovskite compound represented by the composition formula ABX3. The photoelectric conversion layer 7 only needs to contain a perovskite compound represented by the composition formula ABX3 and may also contain defects or impurities.

[0081] The photoelectric conversion layer 7 may further contain other compounds different from the perovskite compound represented by the composition formula ABX3. Examples of the other different compounds are compounds having a Ruddlesden-Popper type layered perovskite structure.

[0082] (Hole transport layer 8) The hole transport layer 8 contains a hole transport material. The hole transport material is a material that transports holes. The hole transport material is, for example, an organic semiconductor or an inorganic semiconductor.

[0083] The hole transport layer 8 may contain an organic semiconductor. The organic semiconductor can form a good interface with the photoelectric conversion layer 7 and suppress the occurrence of interface defects during bonding. As a result, the photoelectric conversion element can have high photoelectric conversion efficiency and durability.

[0084] Examples of the organic semiconductor are triphenylamine, triallylamine, phenylbenzidine, phenylene vinylene, tetrathiafulvalene, vinyl naphthalene, vinyl carbazole, thiophene, aniline, pyrrole, carbazole, triphenylene, fluorene, azulene, pyrene, pentacene, perylene, acridine, or phthalocyanine.

[0085] Examples of typical organic semiconductors used as hole transport materials include 2,2′,7,7′-tetrakis-(N,N-di-p-methoxyphenylamine)9,9′-spirobifluorene, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (hereinafter also referred to as "PTAA"), poly(3-hexylthiophene-2,5-diyl), poly(3,4-ethylenedioxythiophene), or copper phthalocyanine. These organic semiconductors have excellent hole transport properties. Therefore, the photoelectric conversion efficiency of the photoelectric conversion device can be improved.

[0086] The organic semiconductor may contain at least one selected from the group consisting of 2,2′,7,7′-tetrakis-(N,N-di-p-methoxyphenylamine)9,9′-spirobifluorene and PTAA.

[0087] The inorganic semiconductor used as the hole transport material is a p-type semiconductor. Examples of the inorganic semiconductor include Cu2O, CuGaO2, CuSCN, CuI, NiO x , MoO x , V2O5, or a carbon material such as graphene oxide. Here, x > 0.

[0088] The hole transport layer 8 may include a plurality of layers made of different materials. For example, a plurality of layers may be laminated such that the ionization potential of the hole transport layer 8 gradually decreases with respect to the ionization potential of the photoelectric conversion layer 7. Thereby, the hole transport characteristics are improved.

[0089] The thickness of the hole transport layer 8 may be 1 nm or more and 1000 nm or less, or may be 10 nm or more and 50 nm or less. Thereby, sufficient hole transport characteristics can be exhibited. Therefore, the low resistance of the solar cell can be maintained and high photoelectric conversion efficiency can be realized.

[0090] The hole transport layer 8 is formed, for example, by a coating method, a printing method, or a vapor deposition method. This is the same as the photoelectric conversion layer 7. Examples of the coating method include the doctor blade method, the bar coating method, the spray method, the dip coating method, or the spin coating method. An example of the printing method is the screen printing method. If necessary, a plurality of materials may be mixed to produce the hole transport layer 8, and it may be pressurized or fired, etc. When the material of the hole transport layer 8 is an organic low molecular weight substance or an inorganic semiconductor, it is also possible to produce the hole transport layer 8 by a vacuum vapor deposition method.

[0091] The hole transport layer 8 may contain not only a hole transport material but also an additive in order to enhance conductivity. Examples of the additive are a supporting electrolyte, a solvent, or a dopant. The supporting electrolyte and the solvent have the effect of stabilizing holes in the hole transport layer 8. The dopant has the effect of increasing the number of holes in the hole transport layer 8.

[0092] Examples of the supporting electrolyte are ammonium salts, alkaline earth metal salts, or transition metal salts. Examples of the ammonium salts are tetrabutylammonium perchlorate, tetraethylammonium hexafluorophosphate, imidazolium salts, or pyridinium salts. Examples of the alkali metal salts are lithium perchlorate or potassium tetrafluoroborate. An example of the alkaline earth metal salt is calcium(II) bis(trifluoromethanesulfonyl)imide. Examples of the transition metal salts are zinc(II) bis(trifluoromethanesulfonyl)imide or cobalt(III) tris[4-tert-butyl-2-(1H-pyrazol-1-yl)pyridine] tris(trifluoromethanesulfonyl)imide.

[0093] Examples of the dopant are fluorine-containing aromatic boron compounds. An example of the fluorine-containing aromatic boron compound is tris(pentafluorophenyl)borane.

[0094] The solvent contained in the hole transport layer 8 may have excellent ionic conductivity. The solvent may be an aqueous solvent or an organic solvent. To better stabilize the solute, the solvent contained in the hole transport layer 8 may be an organic solvent. Examples of organic solvents are heterocyclic compound solvents such as tert-butylpyridine, pyridine, and n-methylpyrrolidone.

[0095] An ionic liquid may be used as the solvent. The ionic liquid may be used alone or mixed with other solvents. The ionic liquid is desirable in that it has low volatility and high flame retardancy.

[0096] Examples of ionic liquids are imidazolium-based, pyridine-based, alicyclic amine-based, aliphatic amine-based, or azonium amine-based such as 1-ethyl-3-methylimidazolium tetracyanoborate.

[0097] The hole transport layer 8 may contain at least one selected from the group consisting of tert-butylpyridine, calcium(II) bis(trifluoromethanesulfonyl)imide, zinc(II) bis(trifluoromethanesulfonyl)imide, tris[4-tert-butyl-2-(1H-pyrazol-1-yl)pyridine]cobalt(III) tris(trifluoromethanesulfonyl)imide, and tris(pentafluorophenyl)borane as an additive. Thereby, the hole transport characteristics of the hole transport layer 8 are improved. Therefore, the photoelectric conversion efficiency of the photoelectric conversion element can be improved.

[0098] (Second Electrode 9) The second electrode 9 has conductivity.

[0099] When the photoelectric conversion element does not include the hole transport layer 8, the second electrode 9 has a blocking property with respect to electrons from the photoelectric conversion layer 7. In this case, the second electrode 9 does not form an ohmic contact with the photoelectric conversion layer 7. The blocking property with respect to electrons from the photoelectric conversion layer 7 means a property of allowing only holes generated in the photoelectric conversion layer 7 to pass through and not allowing electrons to pass through. The Fermi energy of a material having such a property is lower than the energy of the lower end of the conduction band of the photoelectric conversion layer 7. The Fermi energy of a material having such a property may also be lower than the Fermi energy of the photoelectric conversion layer 7. Specific materials include carbon materials such as platinum, gold, or graphene.

[0100] When the photoelectric conversion element includes the hole transport layer 8, the second electrode 9 may not have a blocking property with respect to electrons from the photoelectric conversion layer 7. In this case, the second electrode 9 can be composed of a material capable of forming an ohmic contact with the photoelectric conversion layer 7. Thereby, the second electrode 9 can be formed to have translucency.

[0101] Among the first electrode 5 and the second electrode 9, at least the electrode on the light incident side may have translucency. Therefore, one of the first electrode 5 and the second electrode 9 does not have to have translucency. That is, one of the first electrode 5 and the second electrode 9 does not have to use a translucent material and does not have to have a pattern including an opening portion for transmitting light.

[0102] (porous layer 10) The porous layer 10 is formed on the electron transport layer 6, for example, by a coating method. When the photoelectric conversion element does not include the electron transport layer 6, it is formed on the first electrode 5.

[0103] The pore structure introduced by the porous layer 10 serves as a base when forming the photoelectric conversion layer 7. The porous layer 10 does not inhibit the light absorption of the photoelectric conversion layer 7 and the electron transfer from the photoelectric conversion layer 7 to the electron transport layer 6.

[0104] The porous layer 10 includes a porous body.

[0105] The porous body is formed, for example, by a continuous array of insulating or semiconductor particles. Examples of insulating particles are aluminum oxide particles or silicon oxide particles. Examples of semiconductor particles are inorganic semiconductor particles. Examples of inorganic semiconductors are metal oxides, perovskite oxides of metal elements, sulfides of metal elements, or metal chalcogenides. Examples of metal oxides are oxides of Cd, Zn, In, Pb, Mo, W, Sb, Bi, Cu, Hg, Ti, Ag, Mn, Fe, V, Sn, Zr, Sr, Ga, Si, or Cr. The metal oxide is, for example, TiO2. Examples of perovskite oxides of metal elements are SrTiO3 or CaTiO3. Examples of sulfides of metal elements are CdS, ZnS, In2S3, PbS, Mo2S, WS2, Sb2S3, Bi2S3, ZnCdS2, or Cu2S. Examples of metal chalcogenides are CsSe, In2Se3, WSe2, HgS, PbSe, or CdTe.

[0106] The thickness of the porous layer 10 may be 0.01 μm or more and 10 μm or less, or may be 0.05 μm or more and 1 μm or less.

[0107] Regarding the surface roughness of the porous layer 10, the surface roughness coefficient given by the effective area / projected area may be 10 or more, or may be 100 or more. The projected area is the area of the shadow formed behind when the object is illuminated with light from the front. The effective area is the actual surface area of the object. The effective area can be calculated from the volume obtained from the projected area and thickness of the object, and the specific surface area and bulk density of the material constituting the object. The specific surface area is measured, for example, by the nitrogen adsorption method.

[0108] The voids in the porous layer 10 are connected from one main surface of the porous layer 10 to the other main surface. That is, the voids in the porous layer 10 are connected from the main surface of the porous layer 10 in contact with the photoelectric conversion layer 7 to the main surface of the porous layer 10 in contact with the electron transport layer 6. Thereby, the material of the photoelectric conversion layer 7 can fill the voids of the porous layer 10 and reach the electron transport layer 6. Therefore, even if the porous layer 10 is provided, since the photoelectric conversion layer 7 and the electron transport layer 6 are in direct contact, the transfer of electrons is possible.

[0109] By providing the porous layer 10, an effect that the photoelectric conversion layer 7 can be easily formed is obtained. By providing the porous layer 10, the material of the photoelectric conversion layer 7 penetrates into the voids of the porous layer 10, and the porous layer 10 serves as a scaffold for the photoelectric conversion layer 7. Therefore, it is less likely that the material of the photoelectric conversion layer 7 is repelled or aggregated on the surface of the porous layer 10. Therefore, the photoelectric conversion layer 7 can be easily formed as a uniform film. The photoelectric conversion layer 7 can be formed by the above-described coating method, printing method, vapor deposition method, or the like.

[0110] It is also expected that the optical path length of the light passing through the photoelectric conversion layer 7 increases due to light scattering caused by the porous layer 10. When the optical path length increases, it is predicted that the amounts of electrons and holes generated in the photoelectric conversion layer 7 increase.

[0111] (Intermediate layer 11) The intermediate layer 11 contains fullerene (C 60 ), C 60 derivative, or a self-assembled monolayer having C 60 (hereinafter, also referred to as "C60SAM"). Since the intermediate layer 11 efficiently collects electrons, the resistance loss when transporting electrons to the electron transport layer 6 is reduced.

[0112] C 60 Examples of the derivative are [6,6]-Phenyl C 61 butyric acid methyl ester or [6,6]-Phenyl-C 61It is butyl butyrate. Examples of C60SAM include 4-(1′,5′-Dihydro-1′-methyl-2′H-[5,6]fullereno-C 60 -Ih-[1,9-c]pyrrol-2′-yl)benzoic acid, (1,2-Methanofullerene C 60 )-61-carboxylic acid, or C 60 Pyrrolidine tris-acid.

[0113] The intermediate layer 11 is formed, for example, by a coating method using a solution, a dipping method, a printing method, or a vapor deposition method.

Examples

[0114] Hereinafter, the present disclosure will be described in more detail with reference to examples and comparative examples.

[0115] In the examples and comparative examples, perovskite solar cells were fabricated, and the initial characteristics, characteristics after a light resistance test, and characteristics after a heat resistance test of the solar cells were evaluated.

[0116] The configurations of the photoelectric conversion elements in the solar cells of Examples 1 to 3 and Comparative Examples 1 to 4 are as follows. · Substrate: Glass substrate (thickness: 0.7 mm) · First electrode: Transparent electrode (indium-tin composite oxide layer) (thickness: 200 nm) · Electron transport layer: Titanium oxide (TiO2) (thickness: 10 nm) · Porous layer: Mesoporous structure titanium oxide (TiO2) · Intermediate layer: 4-(1′,5′-Dihydro-1′-methyl-2′H-[5,6]fullereno-C 60 -Ih-[1,9-c]pyrrol-2′-yl)benzoic acid (i.e., C60SAM) (manufactured by Sigma-Aldrich) · Photoelectric conversion layer: Layer mainly containing HC(NH2)2PbI3 (thickness: 500 nm) · Hole transport layer: a layer containing n-butylammonium bromide (manufactured by Greatcell Solar) and a layer mainly containing PTAA (however, as an additive, tris(pentafluorophenyl)borane (TPFPB) (manufactured by Tokyo Chemical Industry Co., Ltd.) is included) (thickness: 50 nm) · Second electrode: Au (thickness: 200 nm)

[0117] <Fabrication of the photoelectric conversion element> (Example 1) First, a glass substrate having a thickness of 0.7 mm was prepared. This substrate serves as a support material in the solar cell of the present disclosure.

[0118] A layer of indium-tin composite oxide was formed on the substrate by sputtering. In this way, the first electrode was formed.

[0119] Next, a layer of titanium oxide was formed on the first electrode by sputtering. In this way, the electron transport layer was formed.

[0120] After applying 30NR-D (manufactured by Great Cell Solar) on the electron transport layer by spin coating and then firing at 500 °C for 30 minutes, a layer of titanium oxide having a mesoporous structure was formed. In this way, the porous layer was formed.

[0121] Next, the substrate formed up to the porous layer was immersed in a C60SAM solution for 30 minutes and then taken out. Here, the C60SAM solution was obtained by adding C60SAM to a mixed solution of tetrahydrofuran (manufactured by Fujifilm Wako Pure Chemical Corporation) and ethanol (manufactured by Fujifilm Wako Pure Chemical Corporation) mixed at a volume ratio of 1:1 so that the concentration became 1×10 -5 mol / L. After thoroughly rinsing the taken-out substrate with an ethanol solution, it was annealed on a hot plate at a temperature of 100 °C for 30 minutes. After annealing, by naturally cooling to room temperature, a substrate modified with C60SAM was obtained. In this way, the intermediate layer was formed.

[0122] Next, a raw material solution of the photoelectric conversion material was applied by spin coating to form a photoelectric conversion layer containing a perovskite compound. The raw material solution was a solution containing 0.92 mol / L of lead(II) iodide (manufactured by Tokyo Chemical Industry), 0.17 mol / L of lead(II) bromide (manufactured by Tokyo Chemical Industry), 0.83 mol / L of formamidinium iodide (manufactured by GreatCell Solar), 0.17 mol / L of methylammonium bromide (manufactured by GreatCell Solar), 0.05 mol / L of cesium iodide (manufactured by Iwatani Corporation), and 0.05 mol / L of rubidium iodide (manufactured by Iwatani Corporation). The solvent of the solution was a mixture of dimethyl sulfoxide (manufactured by acros) and N,N-dimethylformamide (manufactured by acros). The mixing ratio (DMSO:DMF) of dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF) in this raw material solution was 1:4 by volume.

[0123] Next, a solution containing 6.49×10 -3 mol / L of n-butylammonium bromide was applied by spin coating on the photoelectric conversion layer. The solvent was 2-propanol. Further, a hole transport layer was formed by applying a raw material solution of a hole transport material by spin coating. The raw material solution contained 10 g / L of PTAA and TPFPB, and the solvent was toluene (manufactured by acros).

[0124] Next, the second electrode 9 was formed by depositing an Au film by vacuum evaporation on the hole transport layer. Thus, a photoelectric conversion element was obtained on a glass substrate as a support.

[0125] Next, the photoelectric conversion element was encapsulated in a glove box in which the oxygen concentration was adjusted to 100 ppm. Here, the moisture concentration in the glove box was 0.1 ppm or less in terms of volume fraction. The photoelectric conversion element was encapsulated with a UV curable resin, a cover glass, and a glass substrate. That is, the photoelectric conversion element including the first electrode, the electron transport layer, the porous layer, the photoelectric conversion layer, the hole transport layer, and the second electrode was encapsulated with a UV curable resin, a cover glass, and a glass substrate. Thus, the solar cell according to Example 1 was obtained. In the solar cell according to Example 1, the oxygen concentration in the encapsulation space was 100 ppm.

[0126] (Example 2) In Example 2, the photoelectric conversion element was encapsulated in a glove box in which the oxygen concentration was adjusted to 1000 ppm. Except for this, in the same manner as in Example 1, the solar cell according to Example 2 was obtained.

[0127] (Example 3) In Example 3, the photoelectric conversion element was encapsulated in a glove box in which the oxygen concentration was adjusted to 3000 ppm. Except for this, in the same manner as in Example 1, the solar cell according to Example 3 was obtained.

[0128] (Example 4) In Example 4, the photoelectric conversion element was encapsulated in a glove box in which the oxygen concentration was adjusted to 10 ppm. Except for the above, in the same manner as in Example 1, the solar cell according to Example 4 was obtained.

[0129] (Comparative Example 1) In Comparative Example 1, the photoelectric conversion element was encapsulated in a glove box in which the oxygen concentration was adjusted to 1 ppm. Except for this, in the same manner as in Example 1, the solar cell according to Comparative Example 1 was obtained.

[0130] (Comparative Example 2) In Comparative Example 2, the photoelectric conversion element was encapsulated in a glove box in which the oxygen concentration was adjusted to 10000 ppm. Except for this, in the same manner as in Example 1, the solar cell according to Comparative Example 2 was obtained.

[0131] (Comparative Example 3) In Comparative Example 3, the photoelectric conversion element was sealed in a glove box in which the oxygen concentration was adjusted to 100,000 ppm. Other than this, a solar cell according to Comparative Example 3 was obtained in the same manner as in Example 1.

[0132] <Measurement of photoelectric conversion efficiency> The photoelectric conversion efficiencies of the solar cells according to Examples 1 to 4 and Comparative Examples 1 to 3 were measured.

[0133] The measurement of the photoelectric conversion efficiency of the solar cell was performed using an electrochemical analyzer (ALS440B, manufactured by BAS) and a xenon light source (BPS X300BA, manufactured by Spectro Instruments) for the initial state, after the light resistance test, and after the heat resistance test. Before the measurement, the light intensity was calibrated to 1 Sun (100 mW / cm 2 ) using a silicon photodiode. The voltage sweep rate was 100 mV / s. Before the start of the measurement, pre-adjustments such as light irradiation and long-term forward bias application were not performed. In order to fix the effective area and reduce the influence of scattered light, the solar cell was irradiated with light from the masked glass substrate side in a state where the solar cell was masked with a black mask having an opening of 0.1 cm 2 . The measurement of the photoelectric conversion efficiency was performed at room temperature under dry air (<2% RH). The open-circuit voltage (V OC ), short-circuit current density (Jsc), fill factor (FF), and photoelectric conversion efficiency (Eff) measured as described above are shown in Table 1.

[0134]

Table 1

[0135] <Light resistance test> A light resistance test was performed on the solar cells according to Examples 1 to 4 and Comparative Examples 1 to 3. In the light resistance test, light equivalent to 1 Sun was irradiated from the substrate side for 71 hours while maintaining the temperature of the substrate at 50 °C while maintaining the voltage and current of the solar cell near the optimum operating point. After the light resistance test, the photoelectric conversion efficiency of the solar cell was measured by the above method. The measurement results are shown in Table 2.

[0136]

Table 2

[0137] <Heat Resistance Test> For the solar cells according to Examples 1 to 4 and Comparative Examples 1 to 3, a heat resistance test was carried out. The solar cells were maintained at 85 °C for 331 hours in a constant temperature bath. After the heat resistance test, the photoelectric conversion efficiency of the solar cells was measured by the above method. The measurement results are shown in Table 3.

[0138]

Table 3

[0139] Figure 5 is a graph showing the oxygen concentration dependence of the normalized photoelectric conversion efficiency of the solar cells of Examples 1 to 4 and Comparative Examples 1 to 3. Figure 6 is a graph showing the oxygen amount dependence of the normalized photoelectric conversion efficiency of the solar cells of Examples 1 to 4 and Comparative Examples 1 to 3. The normalized photoelectric conversion efficiency in Figures 5 and 6 is normalized with the largest photoelectric conversion efficiency among Examples 1 to 4 and Comparative Examples 1 to 3 as 1 in each case of the initial state, after the light resistance test, and after the heat resistance test. Figure 6 is obtained by converting the horizontal axis of Figure 5 from the oxygen concentration in the sealed space to the value obtained by dividing the oxygen amount by the surface area of the surface facing the sealed space of the photoelectric conversion element. The ideal gas equation of state was used for the conversion. The volume of the sealed space of the solar cells of Examples 1 to 4 and Comparative Examples 1 to 3 is approximately 1.4×10 -7 m 3 and the surface area of the surface facing the sealed space of the photoelectric conversion element was 2.6×10 -4 m 2 .

[0140] <Effect of Oxygen Concentration on Initial Solar Cell Characteristics> As shown in Table 1 and Figure 5, there was no significant difference in the initial photoelectric conversion efficiency when the oxygen concentration in the sealed space was 3000 ppm or less, and it was stable in the absence of light irradiation and heating. On the other hand, when the oxygen concentration was 10000 ppm or more, the photoelectric conversion efficiency decreased, and the higher the oxygen concentration, the greater the decrease. This is considered to be due to the oxidation of the perovskite compound by excessive oxygen.

[0141] <Effect of Oxygen Concentration on Solar Cell Characteristics after Light Resistance Test> As shown in Table 2 and Figure 5, it was found that the photoelectric conversion efficiency after the light resistance test was a good value in the range where the oxygen concentration in the sealed space was 10 ppm or more and 3000 ppm or less. On the other hand, in the low oxygen concentration region with an oxygen concentration of 1 ppm and the high oxygen concentration region with an oxygen concentration of 10000 ppm or more, the photoelectric conversion efficiency decreased. In particular, the decrease in light resistance was remarkable in Comparative Examples 2 and 3. This is considered to be because when the oxygen concentration is 10000 ppm or more, due to the deterioration phenomenon induced by excessive oxygen, a large amount of reaction products with oxygen (metal oxides or metal hydroxides) or decomposition products of perovskite (metal iodides) are generated on the surface and / or grain boundaries of the perovskite compound, inhibiting carrier movement. On the other hand, in the case of trace oxygen, these products contribute to the termination of defects in the perovskite compound, but when the oxygen concentration is 1 ppm or less, the defect termination under light irradiation is not sufficient, and the solar cell characteristics are considered to have decreased due to carrier recombination by defect levels.

[0142] <Effect of Oxygen Concentration on Solar Cell Characteristics after Heat Resistance Test> As shown in Table 3 and FIG. 5, it was found that when the oxygen concentration in the sealed space is in the range of 100 ppm or more and 3000 ppm or less, the photoelectric conversion efficiency after the heat resistance test is also a good value. On the other hand, in the low oxygen concentration region with an oxygen concentration of 10 ppm and the high oxygen concentration region with an oxygen concentration of 10000 ppm or more, the photoelectric conversion efficiency was less than 15%. The reason for the existence of the optimal oxygen concentration range is the same as that in the light resistance test and the heat resistance test. However, different from the case of the light resistance test, in the case of the heat resistance test, the lower limit value of the optimal oxygen concentration range is high. This is considered to be because the types and densities of defects generated in the perovskite compound are different under light irradiation and in the heating state. In addition, as the energy of the light irradiated in the light resistance test and the heating temperature in the heat resistance test increase, new defects may occur according to the activation energy of various defect generations. However, since the conditions of the light resistance test and the heat resistance test in this example were set assuming the actual operation outdoors, the optimal oxygen concentration range found by the example does not change for improving the durability of the solar cell.

[0143] From the above results, if the oxygen concentration in the sealed space is in the range of 10 ppm or more and 3000 ppm or less, the durability of the solar cell can be improved. When the oxygen concentration in the sealed space is in the range of 100 ppm or more and 3000 ppm or less, both light stability and thermal stability can be achieved.

Industrial Applicability

[0144] This disclosure can greatly improve the durability of solar cells and can be said to have extremely high industrial applicability.

Explanation of Reference Numerals

[0145] 1, 100, 200, 300 Photoelectric conversion element 2 Support material 3 Encapsulant 4 Substrate 5 First electrode 6 Electron transport layer 7 Photoelectric conversion layer 8 Hole transport layer 9 Second electrode 10 Porous layer 11 Intermediate layer 1000 Solar cell

Claims

1. A support member, a photoelectric conversion element, and a sealing material, characterized by comprising: the photoelectric conversion element is disposed inside a sealed space sealed by the support member and the sealing material; the photoelectric conversion element includes a first electrode, a photoelectric conversion layer, and a second electrode, in this order; The value obtained by dividing the amount of oxygen in the sealed space by the surface area of the surface of the photoelectric conversion element facing the sealed space is 2.3×10 -7 mol / m 2 or more and 7.0×10 -5 mol / m 2 or less. a solar cell.

2. The value obtained by dividing the amount of oxygen by the surface area is 2.3×10 -6 mol / m 2 or more and 7.0×10 -5 mol / m 2 or less. The solar cell according to Claim 1.

3. The value obtained by dividing the amount of oxygen by the surface area is 2.3×10 -6 mol / m 2 or more and 2.3×10 -5 mol / m 2 or less. The solar cell according to Claim 2.

4. A method for manufacturing a solar cell, comprising sealing a photoelectric conversion element including a first electrode, a photoelectric conversion layer, and a second electrode in this order such that a value obtained by dividing the amount of oxygen in the sealing space by the surface area of the surface of the photoelectric conversion element facing the sealing space is 2.3 × 10 -7 mol / m 2 or more and 7.0 × 10 -5 mol / m 2 or less.

5. The value obtained by dividing the amount of oxygen by the surface area is 2.3×10 -6 mol / m 2 or more and 7.0×10 -5 mol / m 2 or less. A method for manufacturing the solar cell according to Claim 4.

6. The value obtained by dividing the amount of oxygen by the surface area is 2.3×10 -6 mol / m 2 or more and 2.3×10 -5 mol / m 2 or less. A method for manufacturing the solar cell according to Claim 5.

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