Method for manufacturing photoelectric conversion element

Abstract

A method for manufacturing a photoelectric conversion element according to an embodiment has a first film formation step and a second film formation step. In the first film formation step, a first layer made of BX2 is formed on a surface of a substrate in a first film formation chamber. In the second film formation step, a second layer made of AX is formed on the first layer made of BX2 in a second film formation chamber. Here, AX is a first ammonium halide, BX2 is a metal halide, A is at least one among CH3NH3, C2H5NH3, C3H7NH3, and C4H9NH3, B is at least one among Pb and Sn, and X is at least one among F, Cl, Br, I, and At.

Description

Photoelectric conversion element manufacturing method

[0001] An embodiment of the present invention relates to a method for manufacturing a photoelectric conversion element.

[0002] Recently, attention has been focused on power generation systems that effectively utilize natural energy or have low environmental impact, such as low carbon dioxide emissions. In particular, solar cells using photoelectric conversion elements made of organic and inorganic materials have been actively researched and developed. Highly productive methods are desirable for manufacturing such photoelectric conversion elements. To meet this need, methods have been proposed for producing the photoelectric conversion layer that constitutes the photoelectric conversion element by coating or printing. Such methods may enable photoelectric conversion elements to be manufactured at lower costs than conventional methods. Meanwhile, for mass production, stable manufacturing of photoelectric conversion elements with high conversion efficiency is also required.

[0003] Japanese Patent No. 6550534 Japanese Patent No. 6526013

[0004] An object of the present invention is to provide a method for producing a photoelectric conversion element that enables stable mass production of perovskite-type photoelectric conversion elements.

[0005] The method for manufacturing a photoelectric conversion element according to the embodiment includes a first film formation step and a second film formation step. In the first film formation step, BX is formed on the surface of a substrate in a first film formation chamber. ２ In the second film formation process, a first layer made of BX ２ A second layer made of AX is formed on a first layer made of BX. The first and second film-forming chambers are each set to a reduced pressure atmosphere, where AX is a primary ammonium halide and BX is a fluorine-containing compound. ２ is a metal halide, and A is CH ３ NH ３ , C ２ H ５ NH ３ , C ３ H ７ NH ３ or C ４ H ９ NH ３B is one or two or more of Pb or Sn, and X is one or two or more of F, Cl, Br, I or At.

[0006] Fig. 1 is a cross-sectional view showing the configuration of an example of a photoelectric conversion element of this embodiment. Fig. 2 is a cross-sectional view showing the configuration of another example of the photoelectric conversion element of this embodiment. Fig. 3 is a schematic view illustrating a method for manufacturing the photoelectric conversion element of this embodiment. Fig. 4 is a schematic view illustrating a method for manufacturing the photoelectric conversion element of this embodiment. Fig. 5 is a schematic view illustrating a method for manufacturing the photoelectric conversion element of this embodiment.

[0007] Hereinafter, a method for manufacturing a photoelectric conversion element according to an embodiment will be described with reference to the drawings.

[0008] FIG. 1 shows an example of a photoelectric conversion element manufactured by the manufacturing method of this embodiment. The photoelectric conversion element 10 shown in FIG. 1 is called a single-type cell having one photoelectric conversion layer. The photoelectric conversion element 10 is configured by stacking a first electrode 11, a first buffer layer 12, a photoelectric conversion layer 13, a second buffer layer 14, and a second electrode 15 on a substrate 16. The first electrode 11 and the second electrode 15 serve as the anode and cathode of the photoelectric conversion element 10. Electricity is extracted from the first electrode 11 and the second electrode 15.

[0009] The photoelectric conversion layer 13 is excited by light incident from the substrate 16 side through the substrate 16, the first electrode 11, and the first buffer layer 12, or by light incident from the second electrode 15 side through the second electrode 15 and the second buffer layer 14, generating electrons or holes in the first electrode 11 and the second electrode 15.

[0010] The first buffer layer 12 and the second buffer layer 14 are layers that exist between the photoelectric conversion layer 13 and the two electrodes 11 and 15, but are not necessarily required in the embodiment.

[0011] In this embodiment, the photoelectric conversion element may be, for example, a solar cell or a sensor in which the photoelectric conversion layer contains at least one organic semiconductor material or perovskite structure material.

[0012] Hereinafter, the constituent members of the photoelectric conversion element manufactured according to the embodiment will be described.

[0013] The substrate 16 supports the other components. It is necessary that electrodes can be formed on the surface of the substrate 16. For this reason, it is preferable that the material constituting the substrate 16 is not altered by the heat applied during electrode formation or by organic solvents that come into contact with it. Examples of materials for the substrate 16 include inorganic materials such as alkali-free glass and quartz glass, organic materials such as polyethylene, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide, polyamide, polyamideimide, liquid crystal polymer, and cycloolefin polymer, and metal materials such as stainless steel (SUS) and silicon.

[0014] The substrate 16 may be transparent or opaque, and an appropriate material can be selected depending on the structure of the desired photoelectric conversion element. When light is incident from the substrate 16 side, a transparent substrate is used. When light is incident from the opposite side of the substrate 16, the second electrode 15 can be made of a transparent or translucent material, and the substrate 16 can be made of an opaque material.

[0015] The thickness of the substrate 16 is not particularly limited as long as it has sufficient strength to support the other components.

[0016] When the substrate 16 is disposed on the light incident surface side, an anti-reflection film with a moth-eye structure, for example, can be provided on the light incident surface. This structure allows for efficient capture of light and improves the energy conversion efficiency of the cell. The moth-eye structure has a regular array of protrusions of approximately 100 nm on the surface. This protrusion structure causes the refractive index to change continuously in the thickness direction. Therefore, by using an anti-reflection film as an intermediary, the surface with discontinuous changes in refractive index is eliminated, light reflection is reduced, and cell efficiency is improved.

[0017] The first electrode 11 and the second electrode 15 can be selected from any conventionally known materials as long as they are conductive. However, it is preferable to select the material of the electrode on the light incident side from transparent or semitransparent conductive materials. Examples of transparent or semitransparent electrode materials include conductive metal oxide films and semitransparent metal thin films.

[0018] Specifically, films (NESA, etc.) made of conductive glass made of indium oxide, zinc oxide, tin oxide, and composites thereof such as indium tin oxide (ITO), fluorine-doped tin oxide (FTO), indium zinc oxide, etc., as well as gold, platinum, silver, copper, etc. are used. ITO or FTO is particularly preferred as the conductive oxide.

[0019] When the material of each electrode 11, 15 is ITO, the thickness of each electrode 11, 15 is preferably 30 to 300 nm. If the thickness of each electrode 11, 15 is thinner than 30 nm, the conductivity tends to decrease and the resistance tends to increase. High resistance may cause a decrease in photoelectric conversion efficiency. On the other hand, if the thickness of each electrode 11, 15 is thicker than 300 nm, the flexibility of the ITO film tends to decrease. As a result, if the film is thick, it may crack when stress is applied. It is preferable that the sheet resistance of each electrode 11, 15 is as low as possible, preferably 10 Ω / □ or less.

[0020] Each of the electrodes 11 and 15 may have a single layer structure or a multi-layer structure in which layers made of materials with different work functions are stacked. In the example shown in Fig. 1, the second electrode 15 is composed of a transparent electrode film 15a and a comb-shaped metal electrode film 15b formed on the transparent electrode film 15a.

[0021] When forming each electrode 11, 15 adjacent to the electron transport layer, it is preferable to use a material with a low work function as the electrode material. Examples of low work function materials include alkali metals, alkaline earth metals, and other metals. Specific examples include Li, In, Al, Ca, Mg, Sm, Tb, Yb, Zr, Na, K, Rb, Cs, Ba, and alloys thereof. Furthermore, alloys of metals selected from the low work function materials described above with metals having relatively high work functions selected from gold, silver, platinum, copper, manganese, titanium, cobalt, nickel, tungsten, tin, and the like may be used. Examples of alloys that can be used as electrode materials include lithium-aluminum alloys, lithium-magnesium alloys, lithium-indium alloys, magnesium-silver alloys, calcium-indium alloys, magnesium-aluminum alloys, indium-silver alloys, and calcium-aluminum alloys. When using such metal materials, the film thickness of the electrode is preferably 1 nm to 500 nm, and more preferably 10 nm to 300 nm. If the film thickness is thinner than the above range, the resistance will be too high and the generated charge may not be transmitted sufficiently to the external circuit. If the film thickness is thick, it will take a long time to form the electrode film, which will increase the material temperature and damage other materials, resulting in performance degradation. Furthermore, since a large amount of material is used, the film formation equipment will be occupied for a long time, which may lead to increased costs.

[0022] Organic materials can also be used as electrode materials. For example, polythiophene-based polymers such as polyethylenedioxythiophene (hereinafter sometimes referred to as PEDOT) are preferred. Such polythiophene-based polymers are commercially available, such as Clevios P ​​H 500, Clevios P ​​H, Clevios P ​​VP Al 4083, and Clevios HIL 1,1 (all trade names, manufactured by Starck). The work function of PEDOT is 4.4 eV, but the work function of the electrode can be adjusted by combining it with another material. For example, by mixing PEDOT with polystyrene sulfonate (hereinafter sometimes referred to as PSS), the work function can be adjusted to a range of 5.0 to 5.8 eV.

[0023] The photoelectric conversion layer 13 has a perovskite structure. This perovskite structure is one type of crystal structure, and refers to the same crystal structure as perovskite. Typically, the perovskite structure is composed of ions A, B, and X, and may take on a perovskite structure when ion B is smaller than ion A. The chemical composition of this crystal structure can be expressed by the following general formula (1):

[0024] ABX ３ …(1)

[0025] Here, A can be a primary ammonium ion. Specifically, CH ３ NH ３ ＋ (hereinafter referred to as MA), C ２ H ５ NH ３ ＋ , C ３ H ７ NH ３ ＋ , C ４ H ９ NH ３ ＋ , and HC(NH ２ ) ２ ＋ (hereinafter referred to as FA), etc., and CH ３ NH ３ ＋ is preferable, but not limited to this. ＋ , 1,1,1-trifluoro-ethylammonium iodide (FEAI) are also preferred, but are not limited to these.

[0026] Also, B is a divalent metal ion, Pb ２＋ or Sn ２＋ Preferably, but not limited to, X is a halogen ion, for example, F － , Cl － ,Br － , I － , and At － is selected from Cl － ,Br － , I －is preferred, but is not limited to this.

[0027] The materials constituting the ions A, B, and X may be a single material or a mixture of materials. The constituting ions are ABX ３ It can function without necessarily matching the stoichiometric ratio.

[0028] The ions A constituting the perovskite of the photoelectric conversion layer 13 preferably have an atomic weight or the sum of the atomic weights constituting the ions (molecular weight) of 45 or more. It is even more preferable to include ions of 133 or less. Because ions A meeting these conditions have low stability alone, they may be mixed with common MA (molecular weight 32). However, mixing MA approaches the band gap of silicon, 1.1 eV, which is undesirable for a tandem ion that divides wavelengths to improve efficiency, as this reduces the overall characteristics. Furthermore, when ions A are a combination of multiple ions and include Cs, it is more preferable that the ratio of the number of Cs to the total number of ions A is 0.1 to 0.9.

[0029] This crystal structure has a unit lattice such as a cubic, tetragonal, or rectangular crystal, with A located at each vertex, B located at the body center, and X located at each face center of the cubic crystal, centered around this. In this crystal structure, an octahedron consisting of one B and six Xs contained in the unit lattice is easily distorted by interaction with A, undergoing a phase transition to a symmetrical crystal. It is presumed that this phase transition dramatically changes the physical properties of the crystal, causing electrons or holes to be released from the crystal, resulting in power generation.

[0030] Increasing the thickness of the photoelectric conversion layer 13 increases the amount of light absorption and the short-circuit current density (Jsc), but the carrier transport distance increases, which tends to increase loss due to deactivation. Therefore, there is an optimal film thickness to obtain maximum efficiency, and the film thickness is preferably 30 nm to 1000 nm, and more preferably 60 to 600 nm.

[0031] For example, by individually adjusting the thickness of the photoelectric conversion layer 13, it is possible to adjust the photoelectric conversion element 10 according to the embodiment and other general elements so that they have the same conversion efficiency under sunlight irradiation conditions. However, because the film quality is different, under low illumination conditions such as 200 lux, the photoelectric conversion element 10 according to the embodiment can achieve a higher conversion efficiency than the general elements.

[0032] The first buffer layer 12 and the second buffer layer 14 are sandwiched between the photoelectric conversion layer 13 and the first electrode 11 or the second electrode 15. When these layers are present, one of them functions as a hole transport layer, and the other functions as an electron transport layer. In order to achieve better conversion efficiency, it is preferable that the photoelectric conversion element 10 includes these layers, but these are not necessarily required in the embodiment, and one or both of them may be omitted.

[0033] The electron transport layer has the function of efficiently transporting electrons. When the first buffer layer 12 or the second buffer layer 14 functions as an electron transport layer, this layer preferably contains either a halide or a metal oxide. Suitable examples of the halide include LiF, LiCl, LiBr, LiI, NaF, NaCl, NaBr, NaI, KF, KCl, KBr, KI, and CsF. Of these, LiF is particularly preferred.

[0034] Suitable examples of metal oxides include titanium oxide, molybdenum oxide, vanadium oxide, zinc oxide, nickel oxide, lithium oxide, calcium oxide, cesium oxide, and aluminum oxide. Of these, titanium oxide is preferred. As titanium oxide, amorphous titanium oxide obtained by hydrolyzing titanium alkoxide using a sol-gel method is preferred.

[0035] The electron transport layer may also be made of an inorganic material such as metallic calcium.

[0036] When an electron transport layer is provided in the photoelectric conversion element 10, the thickness of the electron transport layer is preferably 20 nm or less. This is because the film resistance of the electron transport layer can be reduced and the conversion efficiency can be increased. On the other hand, the thickness of the electron transport layer can be 5 nm or more. By providing an electron transport layer and ensuring a certain thickness or more, the hole blocking effect can be fully exerted, and it is possible to prevent the generated excitons from being deactivated before releasing electrons and holes. As a result, current can be extracted efficiently.

[0037] The hole transport layer has a function of efficiently transporting holes. When the first buffer layer 12 or the second buffer layer 14 functions as a hole transport layer, this layer can contain a p-type organic semiconductor material or an n-type organic semiconductor material.

[0038] A p-type organic semiconductor can be used as the material for the hole transport layer. A preferred p-type organic semiconductor includes, for example, a copolymer consisting of a donor unit and an acceptor unit. Examples of the donor unit include fluorene and thiophene. Examples of the acceptor unit include benzothiadiazole. Specific examples of suitable materials include polythiophene and its derivatives, polypyrrole and its derivatives, pyrazoline derivatives, arylamine derivatives, stilbene derivatives, triphenyldiamine derivatives, oligothiophene and its derivatives, polyvinylcarbazole and its derivatives, polysilane and its derivatives, polysiloxane derivatives having aromatic amines in the side chain or main chain, polyaniline and its derivatives, phthalocyanine derivatives, porphyrin and its derivatives, polyphenylenevinylene and its derivatives, polythienylenevinylene and its derivatives, benzodithiophene derivatives, and thieno[3,2-b]thiophene derivatives. The hole transport layer may contain a combination of these materials, or a copolymer consisting of the comonomers that constitute these materials may be used. Among these, polythiophene and its derivatives are preferred because they have excellent stereoregularity and relatively high solubility in solvents.

[0039] In addition, as the material for the hole transport layer, a derivative such as poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)] (hereinafter, sometimes referred to as PCDTBT), which is a copolymer containing carbazole, benzothiadiazole, and thiophene, may be used. Furthermore, a copolymer of a benzodithiophene (BDT) derivative and a thieno[3,2-b]thiophene derivative is also preferred. For example, poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl] Other preferred materials include PTB7-Th (PCE10 or PBDTTT-EFT), which has a thienyl group introduced into it, which has weaker electron donating properties than the alkoxy group of PTB7. Furthermore, metal oxides can also be used as the material for the hole transport layer. Suitable examples of metal oxides include titanium oxide, molybdenum oxide, vanadium oxide, zinc oxide, nickel oxide, lithium oxide, calcium oxide, cesium oxide, and aluminum oxide. These materials have the advantage of being inexpensive. Furthermore, thiocyanates such as copper thiocyanate can also be used as the material for the hole transport layer.

[0040] In addition, transport materials such as spiro-OMeTAD can be used as dopants for these semiconductor materials, such as oxygen, 4-tert-butylpyridine, lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI), acetonitrile, tris[2-(1H-pyrazol-1-yl)pyridine]cobalt(III) tris(hexafluorophosphate) salt (commercially available under the trade name "FK102"), and tris[2-(1H-pyrazol-1-yl)pyrimidine]cobalt(III) tris[bis(trisfluoromethylsulfonyl)imide] (MY11).

[0041] Fig. 2 shows another example of a photoelectric conversion element 20. Similar to the case of Fig. 1, the photoelectric conversion element 20 shown in Fig. 2 is configured by stacking a first electrode 21, a first buffer layer 22, a photoelectric conversion layer 23, a second buffer layer 24, and a second electrode 25 on a substrate 26. The first electrode 21, the first buffer layer 22, the photoelectric conversion layer 23, the second buffer layer 24, and the second electrode 25 correspond to the first electrode 11, the first buffer layer 12, the photoelectric conversion layer 13, the second buffer layer 14, and the second electrode 15 in Fig. 1, respectively, and are made of substantially the same material and have substantially the same thickness.

[0042] 2, the surface of the substrate 26 is an uneven surface 26a having a textured structure. As a result, the surface of the first buffer layer 22 is an uneven surface 22a that reflects the uneven surface 26a of the substrate 26. Therefore, the photoelectric conversion layer 23 disposed on the first buffer layer 22 is formed on the uneven surface 22a.

[0043] Next, a method for manufacturing the photoelectric conversion element of this embodiment will be described. In the method for manufacturing the photoelectric conversion element of this embodiment, BX is formed on the surface of the substrate in the first film forming chamber. ２ This manufacturing method includes a first film formation process for forming a first layer made of AX, and a second film formation process for forming a second layer made of AX on the first layer in a second film formation chamber, and the first film formation chamber and the second film formation chamber are each under a reduced pressure atmosphere.

[0044] where AX is a primary ammonium halide and BX ２ is a metal halide, and A is CH ３ NH ３ , C ２ H ５ NH ３ , C ３ H ７ NH ３ or C ４ H ９ NH ３ B is one or two or more of Pb or Sn, and X is one or two or more of F, Cl, Br, I or At.

[0045] The substrate according to this embodiment may be, for example, as described above, a substrate 16 on which a first electrode 11 and a first buffer layer 12 are laminated, or a substrate 26 having a textured uneven surface 26a on which a first electrode 21 and a first buffer layer 22 are laminated. The surface of the substrate is the surface of the first buffer layer 12 or the first buffer layer 22. When the surface of the substrate is the surface of the first buffer layer 12, the surface of the substrate is a flat surface, and when the surface of the substrate is the surface of the first buffer layer 22, the surface of the substrate is an uneven surface 22a.

[0046] The first film formation process can be, for example, a film formation process by vacuum evaporation or chemical vapor deposition (CVD). When the first film formation process is a film formation process by vacuum evaporation, the first film formation chamber is provided with an evaporation source, a heating means for heating the evaporation source, and a sample stage for placing the substrate. In addition, a pressure reduction means such as a vacuum pump for reducing the pressure in the atmosphere is connected to the first film formation chamber.

[0047] The evaporation source is metal halide BX ２ Specifically, the substance to be used is one or more of lead iodide, lead chloride, lead bromide, tin iodide, tin chloride, and tin bromide.

[0048] The heating means can be selected from various means such as resistance heating, electron beam heating, high frequency induction heating, and laser heating.

[0049] The atmosphere in the first film formation chamber is, for example, an inert gas atmosphere such as nitrogen or argon. －１ ~1 x 10 －５ The atmosphere is reduced in pressure in the range of Pa. The temperature of the substrate is, for example, in the range of 20 to 100°C, and more preferably in the range of 20 to 60°C.

[0050] Then, while the first film-forming chamber is kept in a reduced pressure atmosphere, the evaporation source is heated by a heating means to, for example, 400 to 800°C, more preferably 600 to 700°C, to form a metal halide BX ２ is vaporized or sublimated, and is deposited on the surface of a substrate located away from the evaporation source, ２The thickness of the first layer is preferably in the range of 0.1 to 1 μm, and more preferably in the range of 0.2 to 0.7 μm.

[0051] Vacuum deposition has excellent coverage. Therefore, when the surface of the substrate is the flat surface of the first buffer layer 12, the first layer is deposited to a uniform thickness on the first buffer layer 12. Also, as shown in FIG. 3 , when the surface of the substrate is the uneven surface 22a of the first buffer layer 22, the first layer A is deposited to a uniform thickness on the uneven surface 22a of the first buffer layer 22.

[0052] Next, the second film formation process can be, for example, a film formation process by vacuum deposition or chemical vapor deposition (CVD). When the second film formation process is a film formation process by CVD, the second film formation chamber is provided with a raw material supply unit and a sample stage for placing the substrate. In addition, in the case of thermal CVD, for example, a heater is installed in the second film formation chamber, and in the case of plasma CVD, for example, a plasma generation source is installed in the second film formation chamber. In addition, a pressure reduction means such as a vacuum pump for adjusting the atmospheric pressure is connected to the second film formation chamber.

[0053] The raw material is not particularly limited as long as it can form the primary ammonium halide AX, and examples thereof include cesium iodide, formamidinium iodide (FAI), and methylammonium iodide (MAI).

[0054] The atmosphere in the second film formation chamber is, for example, an inert gas atmosphere such as nitrogen or argon. －１ ~1 x 10 －６ The atmosphere is set to a pressure in the range of Pa. The temperature of the substrate is set to, for example, a range of 20 to 100°C, and more preferably a range of 20 to 60°C.

[0055] The atmospheric pressure in the second film formation process is set higher than the atmospheric pressure in the first film formation process in order to prevent the first layer from disappearing due to sublimation, volatilization, etc. If the atmospheric pressure in the second film formation process is lower than the atmospheric pressure in the first film formation process, iodine gas, hydrogen iodide gas, and organic gases may be generated.

[0056] Then, while maintaining the second film formation chamber under a reduced pressure atmosphere, raw materials are supplied into the second film formation chamber and decomposed or activated by heat, plasma, etc., to form a second layer made of AX on the already formed first layer. The thickness of the second layer is preferably in the range of 0.02 to 1 μm, for example, and more preferably in the range of 0.02 to 0.7 μm.

[0057] CVD, like vacuum deposition, offers excellent coverage. Therefore, when the substrate surface is a first layer formed on a flat first buffer layer 12, the second layer is deposited to a uniform thickness on the flat first layer. Also, as shown in FIG. 4 , when the substrate surface is a first layer A formed on a first buffer layer 22 having an uneven surface 22 a, the second layer B is deposited to a uniform thickness on the uneven first layer.

[0058] By carrying out the second film formation process, the second layer B is formed on the heated first layer A. At this time, BX of the first layer ２ The chemical reaction between ABX and AX in the second layer progresses, and as shown in Figure 5, ３ Thus, a photoelectric conversion layer 23 having a perovskite structure and a composition of the above is formed.

[0059] Also, the first layer BX ２ In order to promote the chemical reaction between ABX and AX in the first layer, the first layer and the second layer are heated under a reduced pressure atmosphere after the second film formation process. ３ A heating step may be carried out to form a layer having a perovskite structure comprising the above-mentioned. The heating temperature in the heating step is in the range of 300 to 700°C, more preferably in the range of 300 to 600°C. The atmosphere in the heating step is, for example, an inert gas atmosphere such as nitrogen or argon, and the heating temperature is 1×10 －１ ~1 x 10 －４ The atmosphere is reduced in pressure in the range of Pa.

[0060] After the photoelectric conversion layers 13 and 23 are formed, the second buffer layers 14 and 24 and the second electrodes 15 and 25 are formed, thereby producing the photoelectric conversion elements 10 and 20 shown in FIG. 1 or FIG. 2 .

[0061] Next, a procedure for recovering and reusing the deposits adhering to the inside of the first film forming chamber or the second film forming chamber will be described. ２ However, some of the particles do not adhere to the substrate but adhere to the surfaces of various components arranged inside the first film formation chamber or the second film formation chamber. If these particles are left as they are, contamination may occur. Therefore, in this embodiment, a recovery process and a regeneration process are performed.

[0062] In the recovery process, deposits adhering to the interior of each chamber are recovered from at least one or both of the first film formation chamber after the first film formation process and the second film formation chamber after the second film formation process. For example, each film formation chamber is equipped with an accessory member called an adhesion-preventing member, and deposits adhering to these are recovered. For example, the adhesion-preventing member is removed from each film formation chamber, and the deposits adhering to the surface of the adhesion-preventing member are recovered by physically peeling them off with a scraper or the like. The recovered deposits may be separated for each film formation chamber, or the deposits recovered from each film formation chamber may be mixed to form a mixture.

[0063] The deposits collected from the first film-forming chamber are BX ２ Although the deposits recovered from the second film formation chamber are mainly composed of AX, various impurities may be mixed in. Furthermore, although the deposits recovered from the second film formation chamber are mainly composed of AX, various impurities may be mixed in. Therefore, the deposits cannot be reused as they are, so a regeneration process described below is carried out.

[0064] In the regeneration process, AX and BX are extracted from the recovered deposits. ２ Specifically, a first fractionation step, a second fractionation step, and a solvent removal step are carried out.

[0065] In the first fractionation step, the deposits are mixed with a first solvent and separated into a first solution and a first solid content. The separation can be performed by a conventional solid-liquid separation method such as filtration. Here, the first solvent is used to separate BX from the deposits. ２ The first solvent must be one that dissolves AX and other impurities while not dissolving AX and other impurities. Examples of such a first solvent include dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF).

[0066] By mixing the deposits with the first solvent, the BX contained in the deposits is removed. ２ is dissolved into the first solvent to form a first solution. On the other hand, AX and impurities do not dissolve in the first solvent and remain as solids. In this way, the first solid contains AX and undissolved impurities.

[0067] Next, in the second fractionation step, the first solid fraction obtained in the first fractionation step is mixed with a second solvent to separate it into a second solution and a second solid fraction. Separation can be performed using a conventional solid-liquid separation method such as filtration. Here, the second solvent must be a solvent that dissolves only AX from the first solid fraction while not dissolving other impurities. Examples of such second solvents include chloroform, chlorobenzene, ethanol, and isopropyl alcohol.

[0068] By mixing the first solid content with the second solvent, the AX contained in the first solid content is dissolved into the second solvent, forming a second solution. Meanwhile, the other impurities contained in the first solid content do not dissolve in the second solvent and become the second solid content. Since the second solid content is an impurity, it can be discarded.

[0069] Next, a solvent removal step is performed. In the solvent removal step, the first solvent and the second solvent are removed from the first solution and the second solution, respectively. As a result, BX is removed from the first solution. ２ is recovered from the second solution, and AX is recovered from the second solution. A specific method for removing the first solvent and the second solvent may involve volatilizing or vaporizing the first solvent and the second solvent by heating.

[0070] And the regenerated AX and BX ２ are reused in the first film formation process or the second film formation process, respectively.

[0071] According to the method for manufacturing a photoelectric conversion element of this embodiment, in the first film formation chamber, BX is formed on the surface of the substrate. ２ In the second film-forming chamber, a first layer made of BX ２The second layer made of AX is formed on the first layer made of AX, and the first and second film-forming chambers are each under a reduced pressure atmosphere, which makes it possible to mass-produce photoelectric conversion elements compared to conventional coating methods. ２ When a film containing BX is formed in one film forming chamber, volatile gases may be generated and the degree of vacuum may decrease. ２ Since the first layer made of SiO 2 and the second layer made of AX are formed in this order in different film-forming chambers, there is no risk of the degree of vacuum decreasing.

[0072] Furthermore, according to the method for manufacturing a photoelectric conversion element of this embodiment, after the second film-forming step, the first layer and the second layer are heated in a reduced pressure atmosphere, thereby forming ABX ３ Since a layer having a perovskite structure can be formed, mass production of photoelectric conversion elements becomes possible.

[0073] Furthermore, according to the manufacturing method of the photoelectric conversion element of this embodiment, the atmospheric pressure in the second film formation process is set to a pressure higher than the atmospheric pressure in the first film formation process, so that the second layer can be formed without losing the first layer due to sublimation.

[0074] Furthermore, according to the manufacturing method of the photoelectric conversion element of this embodiment, the first film formation process is a film formation process by vacuum evaporation and the second film formation process is a film formation process by chemical vapor deposition, making it possible to mass-produce photoelectric conversion elements.

[0075] Furthermore, according to the method for manufacturing a photoelectric conversion element of this embodiment, even if a textured structure is provided on the surface of the substrate, by using a film formation means with high coverage in the first film formation step and the second film formation step, it is possible to form a layer with a perovskite structure of uniform thickness.

[0076] Further, according to the method for manufacturing a photoelectric conversion element of this embodiment, there are a step of recovering deposits adhering to the inside of each chamber from at least one or both of the first film formation chamber after the first film formation step and the second film formation chamber after the second film formation step, and a step of recovering AX and BX from the deposits. ２ and a regeneration step of separating the raw materials AX and BX. ２can be effectively utilized.

[0077] Furthermore, according to the method for manufacturing a photoelectric conversion element of this embodiment, the regenerated AX and BX ２ are reused in the first film formation process or the second film formation process, so the raw materials AX and BX ２ can be effectively utilized.

[0078] Furthermore, according to the method for producing a photoelectric conversion element of this embodiment, the regeneration process includes a first separation process in which the deposits are mixed with a first solvent and separated into a first solution and a first solid content, a second separation process in which the first solid content obtained in the first separation process is mixed with a second solvent and separated into a second solution and a second solid content, and a solvent removal process in which the first solvent and the second solvent are removed from the first solution and the second solution, respectively. ２ can be purified and recovered.

[0079] In each of the above embodiments, a method for manufacturing a single-cell solar cell has been described as a method for manufacturing a photoelectric conversion element, but the method for manufacturing a photoelectric conversion element of this embodiment may also be applied to a method for manufacturing a tandem solar cell in which a silicon solar cell and a perovskite solar cell are stacked. In this case, the substrate may be a silicon solar cell, and the first buffer layer described above may be formed on the electrode of the first photoelectric conversion element, and a perovskite photoelectric conversion layer may be further formed thereon by the manufacturing method of this embodiment.

[0080] According to at least one embodiment described above, in the first film formation chamber, BX is formed on the surface of the substrate. ２ In the second film-forming chamber, a first layer made of BX ２ A second layer made of AX is formed on a first layer made of , and the first and second film formation chambers are each set to a reduced pressure atmosphere, which enables stable mass production of photoelectric conversion elements compared to conventional coating methods.

[0081] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention described in the claims and their equivalents.

[0082] 10, 20... photoelectric conversion element, 11, 21... first electrode, 12, 22... first buffer layer, 13, 23... photoelectric conversion layer, 14, 24... second buffer layer, 15, 25... second electrode, 16, 26... substrate, 22a, 26a... uneven surface.

Claims

1. In the first film-forming chamber, BX is applied to the surface of the substrate. ２ a first film formation step of forming a first layer comprising: In the second film forming chamber, ２ a second film-forming step of forming a second layer made of AX on the first layer made of the first film formation chamber and the second film formation chamber are each set to a reduced pressure atmosphere; The method for manufacturing a photoelectric conversion element, wherein the atmospheric pressure in the second film formation step is set to a pressure higher than the atmospheric pressure in the first film formation step. where AX is a primary ammonium halide and BX ２ is a metal halide, and A is CH ３ NH ３ , C ２ H ５ NH ３ , C ３ H ７ NH ３ or C ４ H ９ NH ３ B is one or two or more of Pb or Sn, and X is one or two or more of F, Cl, Br, I or At.

2. After the second film-forming step, the first layer and the second layer are heated in a reduced pressure atmosphere, thereby forming an ABX ３ The method for producing a photoelectric conversion element according to claim 1 , further comprising a heating step of forming a layer having a perovskite structure comprising:

3. 2. The method for manufacturing a photoelectric conversion element according to claim 1, wherein the first film formation step is a film formation step by vacuum evaporation, and the second film formation step is a film formation step by chemical vapor deposition.

4. The method for manufacturing a photoelectric conversion element according to claim 1 , wherein a textured structure is provided on the surface of the substrate.

5. a step of recovering deposits adhering to the inside of each chamber from at least one of the first film formation chamber after the first film formation step and the second film formation chamber after the second film formation step; From the deposit, the AX and the BX ２ The method for manufacturing a photoelectric conversion element according to claim 1 , further comprising a recycling step of separating the photoelectric conversion element from the photoelectric conversion element.

6. The regenerated AX and BX ２ and a second film forming step, each of which is reused in the first film forming step and the second film forming step, respectively.

7. The regeneration step comprises: a first separation step of mixing the deposit with a first solvent and separating the deposit into a first solution and a first solid content; a second fractionation step in which the first solid content obtained by the first fractionation step is mixed with a second solvent to separate the first solid content into a second solution and a second solid content; The method for manufacturing a photoelectric conversion element according to claim 5 , further comprising: a solvent removal step of removing the first solvent and the second solvent from the first solution and the second solution, respectively.