Perovskite thin film, perovskite solar cell, preparation method and application

Abstract

The invention belongs to the photovoltaic field, and particularly relates to a perovskite thin film, a perovskite solar cell, a preparation method and application. The preparation method of the perovskite thin film comprises the following steps: (1) mixing a raw material of a perovskite structure substance, a lead compound additive and a solvent according with a theoretical molar ratio of a chemical formula of the perovskite structure substance to obtain a perovskite precursor solution; (2) carrying out spin coating on the perovskite precursor solution, and then annealing to obtain a perovskite thin film functional layer precursor; and (3) coating the perovskite thin film functional layer precursor with an alkylamine salt solution, and then annealing and cleaning to obtain the perovskite thin film. According to the perovskite thin film prepared by the invention, the surface recombination is reduced, and the open-circuit voltage and the photoelectric conversion efficiency of the perovskite solar cell are improved.

Description

Technical Field

[0001] The present invention belongs to the field of photovoltaics, and in particular relates to a perovskite film, a perovskite solar cell, and a preparation method and use thereof. Background Art

[0002] Perovskite solar cells (PSCs) have attracted widespread attention due to their excellent performance and potential as the next generation of photovoltaic technology. They are expected to further reduce the power-to-weight ratio and have great potential in portable electronics and space photovoltaic power generation. Among them, lead iodide (PbI2) is used as an absorber in most advanced PSCs. Excessive PbI2 helps to increase the grain size, reduce halide vacancies, and promote the formation of more oriented α-phase perovskite crystals; in polycrystalline perovskites, appropriate reaction residues or heating induction allow PbI2 to passivate grain boundary defects. These advantages are conducive to improving the photoelectric conversion efficiency (PCE) of perovskite solar cells, and existing technologies have confirmed that the conversion efficiency of lead halide perovskite solar cells has exceeded 25%.

[0003] However, the unreacted PbI2 crystals at the carrier transport interface are essentially catalytic sites that trigger the decomposition of perovskite structure materials. PbI2 is easily decomposed into metallic lead PbO and gaseous I2 under continuous light and heating. PbO is a recombination center that can promote ion migration, that is, excessive PbI2 will lead to more PbO-rich voids and non-radiative recombination, thereby sacrificing the open circuit voltage (V OC ), resulting in a decrease in photoelectric conversion efficiency.

[0004] Therefore, the present invention urgently needs to develop a perovskite film that can improve the open circuit voltage and photoelectric conversion efficiency. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a perovskite film and a preparation method thereof. The present invention improves the crystallization and crystal size of the film by adding an appropriate lead compound additive to the perovskite film, and then post-treats the film with an alkylamine salt. The alkylamine salt and the lead compound additive form a MAPbI 3-x CI x / MAPbI 3-x I x / MAPbI 3-x Br x The perovskite phase is formed by removing the perovskite surface phase by washing, thereby eliminating the problem of non-radiative recombination caused by adding lead compound additives to the perovskite. Therefore, the perovskite film prepared by the present invention reduces surface recombination and improves the performance of the perovskite solar cell.

[0006] Specifically, the present invention provides a method for preparing a perovskite film, the method comprising the following steps:

[0007] (1) mixing a raw material of a perovskite structure material, a lead compound additive, and a solvent in a theoretical molar ratio that conforms to the chemical formula of the perovskite structure material to obtain a perovskite precursor solution;

[0008] (2) spin coating the perovskite precursor solution and then annealing to obtain a perovskite thin film functional layer precursor;

[0009] (3) coating an alkylamine salt solution on the perovskite film functional layer precursor, followed by annealing and washing to obtain a perovskite film.

[0010] In one or more embodiments, in step (1), the raw materials of the perovskite structure material are AX and BX2; the A-position cation is selected from one or more of formamidinium ion, cesium ion and methylamine ion, the B-position cation is lead ion, and the X-position anion is selected from one or more of bromide ion, iodide ion and chloride ion.

[0011] In one or more embodiments, in step (1), the chemical formula of the perovskite structured material is ABX3; the A-position cation is selected from one or more of formamidinium ion, cesium ion and methylamine ion, the B-position cation is lead ion, and the X-position anion is selected from one or more of bromide ion, iodide ion and chloride ion.

[0012] In one or more embodiments, in step (1), the solvent is selected from one or more of dimethyl sulfoxide, N-methylpyrrolidone and N,N-dimethylformamide.

[0013] In one or more embodiments, in step (1), the concentration of the theoretically generated perovskite structured substance in the perovskite precursor solution is 1-2 mol / L.

[0014] In one or more embodiments, in step (1), the lead compound additive is PbI2 and / or Pb(SCN)2.

[0015] In one or more embodiments, in step (1), in the perovskite precursor solution, the molar ratio of PbI2 as the lead compound additive and the theoretically generated perovskite structure material is (1-5):100.

[0016] In one or more embodiments, in step (1), the concentration of Pb(SCN)2 as a lead compound additive in the perovskite precursor solution is 0.5-5 mg / mL.

[0017] In one or more embodiments, in step (1), the raw materials of the perovskite structure material and the solvent are first mixed in a theoretical molar ratio conforming to the chemical formula of the perovskite structure material, and then a lead compound additive is added to obtain a perovskite precursor solution.

[0018] In one or more embodiments, in step (1), the raw materials of the perovskite structure material, the lead compound additive and the solvent are directly mixed in a theoretical molar ratio conforming to the chemical formula of the perovskite structure material to obtain a perovskite precursor solution.

[0019] In one or more embodiments, in step (2), the coating method of the perovskite precursor solution is spin coating, slit coating, doctor blading, spraying, screen printing or inkjet printing.

[0020] In one or more embodiments, in step (2), the annealing temperature is 100-120°C.

[0021] In one or more embodiments, in step (2), the annealing time is 10-30 min.

[0022] In one or more embodiments, in step (3), in the alkylamine salt solution, the chemical formula of the alkylamine salt is CH3(CH2)nNH3X; wherein 0≤n≤5, n is an integer, and X is a bromide ion, an iodide ion, or a chloride ion.

[0023] In one or more embodiments, in step (3), the solvent in the alkylamine salt solution is isopropanol and / or chlorobenzene.

[0024] In one or more embodiments, in step (3), the concentration of the alkylamine salt in the alkylamine salt solution is 0.5-2 mg / mL.

[0025] In one or more embodiments, in step (3), the alkylamine salt solution is coated by spin coating, blade coating or slit coating.

[0026] In one or more embodiments, in step (3), the annealing temperature is 100-120°C.

[0027] In one or more embodiments, in step (3), the annealing time is 5-10 min.

[0028] In one or more embodiments, in step (3), chlorobenzene and / or isopropanol are used for washing.

[0029] In one or more embodiments, in step (3), the number of cleaning times is ≥1.

[0030] In one or more embodiments, the alkylamine salt is selected from one or more of methylammonium chloride, methylammonium iodide, methylammonium bromide, ethylammonium iodide, ethylammonium bromide, and butylammonium bromide.

[0031] The method for preparing the perovskite film of the present invention further comprises: adding phenylethylamine iodide while adding the lead compound additive to obtain a perovskite precursor solution.

[0032] In one or more embodiments, the concentration of phenylethylamine iodide in the perovskite precursor solution is 0.5-2 mg / mL.

[0033] The present invention provides a perovskite film prepared by the method of the present invention.

[0034] In one or more embodiments, the perovskite thin film includes a perovskite thin film functional layer and a perovskite thin film passivation layer.

[0035] In one or more embodiments, the perovskite thin film functional layer includes an ABX3 type perovskite structure material, the A-position cation is selected from one or more of formamidinium ions, cesium ions and methylamine ions, the B-position cation is a lead ion, and the X-position anion is selected from one or more of bromide ions, iodide ions and chloride ions.

[0036] In one or more embodiments, the thickness of the perovskite thin film functional layer is 400-500 nm.

[0037] In one or more embodiments, the perovskite film passivation layer comprises an alkyl perovskite structure material, wherein the chemical formula of the alkyl perovskite structure material is abx3; in the alkyl perovskite structure material, the a-position cation is selected from CH3(CH2)nNH3 + One or more of, 0≤n≤5, n is an integer, the b-position cation is a lead ion, and the x-position anion is selected from one or more of a bromide ion, an iodide ion or a chloride ion.

[0038] In one or more embodiments, the thickness of the perovskite thin film passivation layer is 1-5 nm.

[0039] In one or more embodiments, the perovskite film has a thickness of 401-505 nm.

[0040] In one or more embodiments, the CH3(CH2)nNH3 + One or more selected from methylamine ion, ethylamine ion and butylamine ion.

[0041] The present invention provides a perovskite solar cell comprising the perovskite film of the present invention.

[0042] The present invention provides a use of the perovskite film in preparing a solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Schematic diagram of the structure of an inverted single-junction perovskite solar cell prepared according to some embodiments of the present invention. DETAILED DESCRIPTION

[0044] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0045] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0046] Herein, “comprising”, “including”, “containing” and similar terms encompass the meanings of “consisting essentially of” and “consisting of”. For example, when “A comprises B and C” is disclosed herein, “A consists essentially of B and C” and “A consists of B and C” should be deemed to be disclosed herein.

[0047] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are only for brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0048] In this document, unless otherwise specified, percentage refers to mass percentage and ratio refers to mass ratio.

[0049] Herein, when describing embodiments or examples, it should be understood that they are not used to limit the present invention to these embodiments or examples. On the contrary, all substitutes, improvements and equivalents of the methods and materials described in the present invention can be included in the scope limited by the claims.

[0050] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0051] The present invention provides a method for preparing a perovskite film, the method comprising the following steps:

[0052] (1) mixing a raw material of a perovskite structure material, a lead compound additive, and a solvent in a theoretical molar ratio that conforms to the chemical formula of the perovskite structure material to obtain a perovskite precursor solution;

[0053] (2) spin coating the perovskite precursor solution and then annealing to obtain a perovskite thin film functional layer precursor;

[0054] (3) coating an alkylamine salt solution on the perovskite film functional layer precursor, followed by annealing and washing to obtain a perovskite film.

[0055] In step (1), the raw materials of the perovskite structure material can be AX and BX2; the cation at the A position can be one or more selected from the group consisting of formamidinium ion, cesium ion and methylamine ion, the cation at the B position can be a lead ion, and the anion at the X position can be one or more selected from the group consisting of bromide ion, iodide ion and chloride ion.

[0056] In step (1), the chemical formula of the perovskite structure material can be ABX3; the A-position cation can be selected from the group consisting of formamidinium ions (FA + ), cesium ion (Cs + ) and methylamine ion (MA + ) in one or more, the B-site cation may be a lead ion (Pb 2+ ), the anion at position X may be selected from bromide (Br - ), iodide ion (I - ) and chloride ions (Cl - )

[0057] In the present invention, the band gap of the perovskite structure material can be 1.6 to 1.8 eV, such as 1.6 eV, 1.65 eV, 1.7 eV, 1.75 eV, and 1.8 eV. In the present invention, the band gap of the perovskite structure material is controlled within the above range. The perovskite structure material has a larger band gap. At this time, excessive PbI2 may affect the uniformity and stability of the band gap. The wide band gap perovskite material is highly sensitive to excessive PbI2, and the alkylamine salt of the present invention can selectively remove excess PbI2 to optimize the photoelectric performance and stability of the material.

[0058] In some embodiments, the formamidinium ion may account for 75%-85% of the total molar amount of A-site cations, based on molar percentage, e.g., 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%.

[0059] In some embodiments, the cesium ions may comprise 10%-20% of the total molar amount of A-site cations, by mole percentage, e.g., 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%.

[0060] In some embodiments, the methylamine ions may account for 0-10% of the total molar amount of A-site cations, for example 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% by mole.

[0061] In some embodiments, the bromide ion can account for 10%-30% of the total molar amount of the anion at the X position, based on molar percentage, such as 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%.

[0062] In some embodiments, the iodide ions may account for 70%-90% of the total molar amount of the anions at the X position, for example, 70%, 72%, 74%, 76%, 78%, 80%, 82%, 84%, 86%, 88%, 90%, in terms of molar percentage. In step (1), the solvent may be one or more selected from dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP) and N,N-dimethylformamide (DMF); the solvent is preferably a mixture of dimethyl sulfoxide and N,N-dimethylformamide in a volume ratio of (0.1-5):10, or the solvent is preferably a mixture of dimethyl sulfoxide, N-methylpyrrolidone and N,N-dimethylformamide in a volume ratio of 1:(0.1-1):(8-9).

[0063] In step (1), the concentration of the theoretically generated perovskite structured substance in the perovskite precursor solution can be 1-2 mol / L, for example, 1 mol / L, 1.2 mol / L, 1.4 mol / L, 1.6 mol / L, 1.8 mol / L, 2 mol / L.

[0064] In step (1), the lead compound additive may be PbI2 and / or Pb(SCN)2. In the present invention, the addition of the lead compound additive can improve the crystallization and crystal size of the thin film, and then the thin film is post-treated with an alkylamine salt, so that the alkylamine salt and the lead compound additive form an alkyl perovskite structure material, and then form a passivation layer, reduce surface recombination, and improve device performance, that is, improve the open circuit voltage and photoelectric conversion efficiency of the perovskite solar cell.

[0065] In step (1), in the perovskite precursor solution, the molar ratio of PbI2 as the lead compound additive and the theoretically generated perovskite structure material can be (1-5):100, for example, 1:100, 2:100, 3:100, 4:100, 5:100. In the present invention, the molar ratio of the lead compound additive and the theoretically generated perovskite structure material is controlled within the above range, which is conducive to promoting the crystallization of the perovskite film, increasing the grain size of the perovskite structure material, and improving the open circuit voltage and photoelectric conversion efficiency of the perovskite solar cell without compromising the performance.

[0066] In step (1), the concentration of Pb(SCN)2 as a lead compound additive in the perovskite precursor solution can be 0.5-5 mg / mL, for example, 0.5 mg / mL, 1.0 mg / mL, 1.5 mg / mL, 2.0 mg / mL, 2.5 mg / mL, 3.0 mg / mL, 3.5 mg / mL, 4.0 mg / mL, 4.5 mg / mL, 5.0 mg / mL.

[0067] In step (1), the raw materials of the perovskite structure material and the solvent in the theoretical molar ratio conforming to the chemical formula of the perovskite structure material can be mixed first, and then the lead compound additive is added to obtain the perovskite precursor solution.

[0068] In step (1), the raw material of the perovskite structure material, the lead compound additive and the solvent in the theoretical molar ratio conforming to the chemical formula of the perovskite structure material can be directly mixed to obtain a perovskite precursor solution. In some embodiments, the raw material of the perovskite structure material can include PbI2, and the lead compound additive is also PbI2. PbI2 can be directly added according to the sum of the amount of PbI2 in the raw material of the perovskite structure material and the amount of PbI2 in the lead compound additive.

[0069] The method for preparing a perovskite film of the present invention further comprises: adding phenylethylamine iodide (PEAI) while adding a lead compound additive to obtain a perovskite precursor solution. In the present invention, the addition of phenylethylamine iodide can improve the crystallization of the perovskite structure material, thereby improving the open circuit voltage and photoelectric conversion efficiency of the perovskite solar cell.

[0070] In the present invention, the concentration of phenylethylamine iodide in the perovskite precursor solution can be 0.5-2 mg / mL, such as 0.5 mg / mL, 0.7 mg / mL, 0.9 mg / mL, 1.0 mg / mL, 1.2 mg / mL, 1.4 mg / mL, 1.6 mg / mL, 1.8 mg / mL, 2.0 mg / mL. In step (2), the coating method of the perovskite precursor solution can be spin coating, slit coating, blade coating, spray coating, screen printing or inkjet printing.

[0071] In step (2), the annealing temperature may be 100-120°C, for example, 100°C, 105°C, 110°C, 115°C, 120°C.

[0072] In step (2), the annealing time can be 10 to 30 min, for example, 10 min, 15 min, 20 min, 25 min, or 30 min.

[0073] In step (3), in the alkylamine salt solution, the chemical formula of the alkylamine salt can be CH3(CH2)nNH3X; wherein 0≤n≤5, n is an integer, and X can be a bromide ion, an iodide ion or a chloride ion; preferably, the alkylamine salt can be selected from methylammonium chloride (MACl, molecular formula CH3NH3Cl), methylammonium iodide (MAI, chemical formula CH3NH3I), methylammonium bromide (MABr, chemical formula CH3NH3Br), ethylammonium iodide (EAI, chemical formula CH3CH2NH3I) and ethylammonium bromide (EABr, chemical formula CH3CH2NH3Br) and butylammonium bromide (BABr, chemical formula CH3CH2CH2CH2NH3Br) One or more. In the present invention, the alkylamine salt and the lead compound additive can form an alkyl perovskite structure material, and then form a passivation layer, reduce surface recombination, and improve device performance, that is, improve the open circuit voltage and photoelectric conversion efficiency of the perovskite solar cell.

[0074] In step (3), in the alkylamine salt solution, the solvent may be isopropyl alcohol (IPA) and / or chlorobenzene.

[0075] In step (3), in the alkylamine salt solution, the concentration of the alkylamine salt can be 0.5-2 mg / mL, such as 0.5 mg / mL, 0.7 mg / mL, 0.9 mg / mL, 1.0 mg / mL, 1.2 mg / mL, 1.4 mg / mL, 1.6 mg / mL, 1.8 mg / mL, 2.0 mg / mL. In the present invention, the concentration of the alkylamine salt is controlled within the above range, which is conducive to promoting the crystallization of the perovskite film, increasing the grain size of the perovskite structure material, and improving the open circuit voltage and photoelectric conversion efficiency of the perovskite solar cell without compromising the performance.

[0076] In step (3), the alkylamine salt solution can be coated by spin coating, blade coating or slit coating.

[0077] In step (3), the annealing temperature may be 100-120°C, for example, 100°C, 105°C, 110°C, 115°C, 120°C.

[0078] In step (3), the annealing time can be 5-10 min, for example, 5 min, 6 min, 7 min, 8 min, 9 min, 10 min.

[0079] In step (3), chlorobenzene (CB) and / or isopropanol may be used for cleaning. In the present invention, the surface phase of the perovskite can be removed by cleaning, thereby eliminating the non-radiative recombination problem caused by adding excessive lead compounds to the perovskite, and improving the open circuit voltage and photoelectric conversion efficiency of the perovskite solar cell.

[0080] In step (3), the number of cleaning times can be ≥1, for example, 2, 3, or 4.

[0081] The invention provides a perovskite film prepared by the method of the invention.

[0082] In the present invention, the perovskite film may include a perovskite film functional layer and a perovskite film passivation layer.

[0083] In the perovskite film of the present invention, the functional layer of the perovskite film may include an ABX3 type perovskite structure material, and the A-position cation may be selected from the group consisting of formamidinium ions (FA + ), cesium ion (Cs + ) and methylamine ion (MA + ) in one or more, the B-site cation may be a lead ion (Pb 2+ ), the anion at position X may be selected from bromide (Br - ), iodide ion (I - ) and chloride ions (Cl - )

[0084] In the perovskite film of the present invention, the thickness of the functional layer of the perovskite film may be 400-500 nm, for example, 400 nm, 420 nm, 440 nm, 460 nm, 480 nm, or 500 nm.

[0085] In the perovskite film of the present invention, the passivation layer of the perovskite film may include an alkyl perovskite structure material, and the chemical formula of the alkyl perovskite structure material may be abx3; in the alkyl perovskite structure material, the a-position cation may be selected from CH3(CH2)nNH3 + One or more of, 0≤n≤5, n is an integer, the cation at position b may be a lead ion, and the anion at position x may be one or more selected from bromide ions, iodide ions and chloride ions; preferably, CH3(CH2)nNH3 + It may be one or more selected from the group consisting of methylamine ion, ethylamine ion and butylamine ion.

[0086] In some embodiments, the ABX3-type perovskite structural material in the perovskite thin film functional layer and the alkyl-type perovskite structural material in the perovskite thin film passivation layer are different.

[0087] In the perovskite film of the present invention, the thickness of the passivation layer of the perovskite film may be 1-5 nm, for example, 1 nm, 2 nm, 3 nm, 4 nm, or 5 nm.

[0088] In the present invention, the thickness of the perovskite film can be 401-505nm, for example, 401nm, 410nm, 420nm, 430nm, 440nm, 450nm, 460nm, 470nm, 480nm, 490nm, and 500nm.

[0089] The present invention provides a perovskite solar cell comprising the perovskite film of the present invention.

[0090] The perovskite solar cell of the present invention may further include a hole transport layer and an electron transport layer.

[0091] In the present invention, the hole transport layer can be selected from one or more of NiOx, [2-(9H-carbazole-9-yl)ethyl]phosphonic acid (2PACz) and [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACz).

[0092] In the present invention, the thickness of the hole transport layer can be 12-103 nm, for example, 12 nm, 15 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, and 100 nm.

[0093] In the present invention, the electron transport layer may be C60 and / or a fullerene derivative (PCBM).

[0094] In the present invention, the thickness of the electron transport layer may be 10-50 nm, for example, 10 nm, 20 nm, 30 nm, 40 nm, or 50 nm.

[0095] In the present invention, the perovskite solar cell may include a single-junction perovskite solar cell and a tandem perovskite solar cell; preferably, the perovskite solar cell may include an inverted single-junction perovskite solar cell and an inverted tandem perovskite solar cell.

[0096] In the present invention, the inverted single-junction perovskite solar cell may include a conductive substrate, a hole transport layer, a perovskite film, an electron transport layer and a back electrode in sequence from the thickness direction.

[0097] In the present invention, a hole blocking layer may be further included between the electron transport layer and the back electrode of the inverted single-junction perovskite solar cell.

[0098] In the present invention, in the inverted single-junction perovskite solar cell, the conductive substrate may be a transparent conductive substrate. Preferably, the transparent conductive substrate may be an indium tin oxide (ITO) transparent conductive substrate and / or a fluorine-doped tin oxide (FTO) transparent conductive substrate.

[0099] In the present invention, in the inverted single-junction perovskite solar cell, the back electrode may be Ag, Cu or Au.

[0100] In the present invention, the inverted stacked perovskite solar cell may include a bottom electrode, a bottom cell, a tunneling layer, an inverted top cell and a top electrode in sequence from the thickness direction, and the inverted top cell may include a hole transport layer, a perovskite film and an electron transport layer in sequence from the thickness direction.

[0101] In the present invention, a hole blocking layer may be further included between the electron transport layer and the back electrode of the inverted stacked perovskite solar cell.

[0102] In the present invention, in the inverted stacked perovskite solar cell, the bottom electrode may include a first transparent electrode layer and a first metal grid line.

[0103] In the present invention, in the inverted stacked perovskite solar cell, the first transparent electrode layer may be indium tin oxide (ITO) and / or fluorine-doped tin oxide (FTO).

[0104] In the present invention, in the inverted stacked perovskite solar cell, the first metal grid line may be Ag, Cu or Au. In the present invention, in the inverted stacked perovskite solar cell, the bottom cell may be a crystalline silicon bottom cell.

[0105] In the present invention, in the inverted stacked perovskite solar cell, the tunneling layer may be indium tin oxide (ITO), indium zinc oxide (IZO) or VTTO (vanadium-doped titanium dioxide).

[0106] In the present invention, in the inverted stacked perovskite solar cell, the top electrode may include a second transparent electrode layer and a second metal grid line.

[0107] In the present invention, in the inverted stacked perovskite solar cell, the second transparent electrode layer may be ITO and / or IZO.

[0108] In the present invention, in the inverted stacked perovskite solar cell, the second metal grid line may be Ag, Cu or Au.

[0109] In the present invention, the perovskite solar cell may further include a passivation layer, and the passivation layer may be between the perovskite thin film layer and the electron transport layer.

[0110] In the present invention, in the inverted single-junction perovskite solar cell, the passivation layer may be between the perovskite thin film layer and the electron transport layer.

[0111] In the present invention, in the inverted stacked perovskite solar cell, the passivation layer may be between the perovskite thin film layer and the electron transport layer.

[0112] In the present invention, the material of the passivation layer may be diammonium salt; preferably, the diammonium salt may be ethylenediamine hydroiodide (EDAI) and / or 1,3-diaminopropane dihydroiodide (PDADI).

[0113] In the present invention, the thickness of the passivation layer may be 1-5 nm, for example, 1 nm, 2 nm, 3 nm, 4 nm, or 5 nm.

[0114] The present invention provides a method for preparing an inverted single-junction perovskite solar cell of the present invention, the method comprising the following steps:

[0115] (1) depositing a hole transport layer on the surface of a conductive substrate;

[0116] (2) depositing a perovskite film on the surface of the hole transport layer;

[0117] (3) depositing an electron transport layer on the surface of the perovskite thin film layer;

[0118] (4) A back electrode is deposited on the surface of the electron transport layer to obtain an inverted single-junction perovskite solar cell.

[0119] The present invention provides a method for preparing an inverted stacked perovskite solar cell of the present invention, the method comprising the following steps:

[0120] (1”) Depositing the bottom electrode and tunneling layer on the two surfaces of the bottom battery respectively,

[0121] (2”) depositing a hole transport layer on the surface of the tunneling layer;

[0122] (3”) depositing a perovskite film on the surface of the hole transport layer;

[0123] (4”) depositing an electron transport layer on the surface of the perovskite thin film layer;

[0124] (5”) A top electrode is deposited on the surface of the electron transport layer to obtain an inverted stacked perovskite solar cell.

[0125] In the present invention, the electron transport layer can be deposited by spin coating or evaporation.

[0126] In the present invention, the hole transport layer can be deposited by sputtering, spin coating, slit coating or doctor blade coating.

[0127] In the present invention, the back electrode can be deposited by spin coating, evaporation, sputtering, blade coating or screen printing.

[0128] In the present invention, the bottom electrode can be deposited by sputtering, chemical vapor deposition or evaporation.

[0129] In the present invention, the tunneling layer may be deposited by sputtering, chemical vapor deposition or evaporation.

[0130] In the present invention, the top electrode can be deposited by spin coating, evaporation, sputtering, blade coating or screen printing.

[0131] In the present invention, the sputtering may be magnetron sputtering.

[0132] In the present invention, the evaporation may be vacuum evaporation.

[0133] The method for preparing a perovskite solar cell of the present invention also includes depositing a passivation layer on the surface of the perovskite film. Preferably, the material of the passivation layer is dissolved in a solvent to prepare a passivation layer precursor solution, the passivation layer precursor solution is coated on the surface of the perovskite film, and then annealed to obtain the passivation layer.

[0134] In the present invention, the concentration of the material of the passivation layer in the passivation layer precursor solution can be 0.5-2 mg / mL, for example 0.5 mg / mL, 0.7 mg / mL, 0.9 mg / mL, 1.0 mg / mL, 1.2 mg / mL, 1.4 mg / mL, 1.6 mg / mL, 1.8 mg / mL, 2.0 mg / mL.

[0135] In the present invention, in the passivation layer precursor solution, the solvent may be one or more selected from toluene, isopropanol and chlorobenzene.

[0136] In the present invention, the coating method of the passivation layer precursor solution can be spin coating, blade coating or slit coating.

[0137] In the present invention, during the preparation of the passivation layer, the annealing temperature may be 100-120°C, for example, 100°C, 105°C, 110°C, 115°C, 120°C.

[0138] In the present invention, in the process of preparing the passivation layer, the annealing time can be 2-10 min, for example, 2 min, 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min, 10 min.

[0139] Compared with the prior art, the present invention has the following beneficial effects: the present invention improves the crystallization of wide bandgap (WBG) perovskite films and increases the grain size without damaging device performance, thereby improving the photoelectric conversion efficiency of the device.

[0140] The present invention will be described below in the form of specific examples. It should be understood that these examples are merely illustrative and are not intended to limit the scope of the present invention. The methods, reagents and materials used in the examples are, unless otherwise stated, conventional methods, reagents and materials in the art. The raw material compounds in the examples can all be purchased through commercial routes.

[0141] Example 1

[0142] Preparation of the present invention Figure 1 The inverted single-junction perovskite solar cell shown in the figure has the following specific steps:

[0143] (1) Selecting 20 ohm ITO glass, cleaning it with deionized water, ethanol and a detergent in sequence, and then treating it under ultraviolet light (UV) for 20 minutes to remove organic impurities to obtain a conductive substrate; sputtering NiOx on the surface of the conductive substrate to obtain a NiOx layer with a thickness of 30 nm, spin-coating a mixed solution of [2-(9H-carbazole-9-yl)ethyl]phosphonic acid and [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (the molar ratio of [2-(9H-carbazole-9-yl)ethyl]phosphonic acid to [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid on the surface of the NiOx layer by a solution method, and annealing at 100° C. for 10 minutes to obtain a self-assembled molecular layer with a thickness of 3 nm, wherein the NiOx layer and the self-assembled molecular layer constitute a hole transport layer;

[0144] (2) FAI powder, MAI powder, CsI powder, PbBr2 powder and PbI2 powder were prepared according to the chemical formula of the perovskite structure material: FA 0.8 Cs 0.15 MA 0.05 Pb(Br 0.25 I 0.75 )3 were mixed with the theoretical molar ratio, dissolved in a mixed solvent of DMF and DMSO (the volume ratio of DMF and DMSO was 4:1), and then 0.5 mg / mL was added PEAI additive and PbI2 (the molar ratio of PbI2 to the theoretically generated perovskite structure material is 2:100) are used to assist crystallization to obtain a perovskite precursor solution, wherein the concentration of the perovskite structure material is 1.7 mol / L, and its band gap is 1.68 eV. Spin coating is performed by a one-step method using anisole anti-solvent, and annealing is performed at 100° C. for 20 min after spin coating to obtain a perovskite film functional layer precursor; 100 μL of a prepared MACl solution is spin coated on the perovskite film functional layer precursor, wherein the solvent of the MACl solution is isopropanol, and the concentration of MACl is 0.5 mg / mL, and annealing is performed at 100° C. for 5 min after spin coating, and CB is used for washing twice, and the perovskite film functional layer precursor is converted into a perovskite film functional layer with a thickness of 450 nm, and a perovskite film passivation layer with a thickness of 3 nm is obtained at the same time, and the perovskite film functional layer and the perovskite film passivation layer constitute a perovskite film;

[0145] (3) dynamically spin-coating a passivation layer precursor solution on the perovskite film by a solution method (wherein the solute is EDAI, the solvent is toluene, and the concentration of EDAI is 1 mg / mL), annealing at 100° C. for 5 min to obtain a passivation layer with a thickness of 3 nm;

[0146] (4) depositing C60 on the surface of the passivation layer by vacuum evaporation to obtain an electron transport layer with a thickness of 30 nm, and depositing BCP on the surface of the electron transport layer by vacuum evaporation to obtain a hole blocking layer with a thickness of 6 nm;

[0147] (5) Ag is deposited on the surface of the hole blocking layer by vacuum evaporation to obtain a back electrode with a thickness of 150 nm, and an inverted single-junction perovskite solar cell is obtained at the same time.

[0148] Example 2

[0149] The other conditions of this embodiment are the same as those of embodiment 1, except that the solute in the alkylamine salt solution of this embodiment is replaced by MAI from MACl.

[0150] Example 3

[0151] The other conditions of this embodiment are the same as those of embodiment 1, except that the solute in the alkylamine salt solution of this embodiment is replaced by MABr from MACl.

[0152] Example 4

[0153] The other conditions of this embodiment are the same as those of embodiment 1, except that the solute in the alkylamine salt solution of this embodiment is replaced by EAI from MACl.

[0154] Example 5

[0155] The other conditions of this embodiment are the same as those of embodiment 1, except that the solute in the alkylamine salt solution of this embodiment is replaced by EABr from MACl.

[0156] Example 6

[0157] The other conditions of this example are the same as those of Example 1, except that in this example, PbI2 (the molar ratio of PbI2 to the theoretically generated perovskite structure material is 2:100) is replaced by 2 mg / mL of Pb(SCN)2.

[0158] Comparative Example 1

[0159] The other conditions of this comparative example are the same as those of Example 1, except that this comparative example does not include the step of "spin coating 100 μL of the prepared MACl solution on the perovskite thin film functional layer precursor, wherein the solvent of the MACl solution is isopropanol, and the concentration of MACl is 0.5 mg / mL, annealing at 100°C for 5 min after spin coating, and washing twice with CB".

[0160] Test Case

[0161] Device performance test of perovskite solar cells: Under 25°C and AM 1.5G standard solar spectrum, a solar simulator was used to set the voltage range to 2V to -0.5V, and the current output of the perovskite solar cells prepared in Examples 1-6 and Comparative Example 1 at different voltages was tested, and the corresponding current-voltage (IV) characteristic curves were plotted, where the cell surface area was 0.09cm 2 , the incident light power (Pin) is 100mW / cm 2 The open circuit voltage, short circuit current density, fill factor and photoelectric conversion efficiency of Examples 1-6 and Comparative Example 1 were obtained according to the characteristic curves.

[0162] (1) Open circuit voltage (Voc): The voltage value corresponding to when the current is equal to zero.

[0163] (2) Short-circuit current density (Jsc): The current value when the voltage is zero is the short-circuit current (Isc), and the current per unit battery surface area is the short-circuit current density.

[0164] (3) Fill factor (FF): The ratio of the maximum output power (Pmax) of the battery to the product of the open circuit voltage and the short circuit current. The calculation formula is (Pmax / Voc*Isc), where the maximum power point is the point where the battery output power reaches its maximum value.

[0165] (4) Photoelectric conversion efficiency (PCE): Photoelectric conversion efficiency refers to the ratio of maximum output power to incident light power (Pin), and the calculation formula is (Pmax / Pin)*100%.

[0166] The test results of the open circuit voltage, short circuit current density, fill factor and photoelectric conversion efficiency of the perovskite solar cells prepared in Examples 1-6 and Comparative Example 1 are shown in Table 1.

[0167] Table 1: Open circuit voltage, short circuit current density, fill factor and photoelectric conversion efficiency of perovskite solar cells prepared in Examples 1-6 and Comparative Example 1

[0168]

[0169]

Claims

1. A method for preparing a perovskite film, characterized in that: The method comprises the following steps: (1) mixing a raw material of a perovskite structure material, a lead compound additive, and a solvent in a theoretical molar ratio that conforms to the chemical formula of the perovskite structure material to obtain a perovskite precursor solution; (2) spin coating the perovskite precursor solution and then annealing to obtain a perovskite thin film functional layer precursor; (3) coating an alkylamine salt solution on the perovskite film functional layer precursor, followed by annealing and washing to obtain a perovskite film.

2. The method according to claim 1, characterized in that The method has one or more of the following features: In step (1), the raw materials of the perovskite structure material are AX and BX2; the A-position cation is selected from one or more of formamidinium ion, cesium ion and methylamine ion, the B-position cation is lead ion, and the X-position anion is selected from one or more of bromide ion, iodide ion and chloride ion; In step (1), the chemical formula of the perovskite structure material is ABX3; the A-position cation is selected from one or more of formamidinium ion, cesium ion and methylamine ion, the B-position cation is lead ion, and the X-position anion is selected from one or more of bromide ion, iodide ion and chloride ion; In step (1), the solvent is selected from one or more of dimethyl sulfoxide, N-methylpyrrolidone and N,N-dimethylformamide; In step (1), the concentration of the theoretically generated perovskite structure material in the perovskite precursor solution is 1-2 mol / L; In step (1), the lead compound additive is PbI2 and / or Pb(SCN)2; in the perovskite precursor solution, the molar ratio of PbI2 as the lead compound additive to the theoretically generated perovskite structure material is (1-5):100; in the perovskite precursor solution, the concentration of Pb(SCN)2 as the lead compound additive is 0.5-5 mg / mL; In step (1), the raw material of the perovskite structure material and the solvent are first mixed in a theoretical molar ratio according to the chemical formula of the perovskite structure material, and then a lead compound additive is added to obtain a perovskite precursor solution; or, the raw material of the perovskite structure material, the lead compound additive and the solvent are directly mixed in a theoretical molar ratio according to the chemical formula of the perovskite structure material to obtain a perovskite precursor solution; In step (2), the coating method of the perovskite precursor solution is spin coating, slit coating, doctor blade coating, spray coating, screen printing or inkjet printing; In step (2), the annealing temperature is 100-120°C; In step (2), the annealing time is 10-30 min; In step (3), in the alkylamine salt solution, the chemical formula of the alkylamine salt is CH3(CH2)nNH3X; wherein 0≤n≤5, n is an integer, and X is a bromide ion, an iodide ion or a chloride ion; In step (3), the solvent in the alkylamine salt solution is isopropanol and / or chlorobenzene; In step (3), the concentration of the alkylamine salt in the alkylamine salt solution is 0.5-2 mg / mL; In step (3), the alkylamine salt solution is coated by spin coating, blade coating or slit coating; In step (3), the annealing temperature is 100-120°C; In step (3), the annealing time is 5-10 min; In step (3), washing is performed using chlorobenzene and / or isopropanol; In step (3), the number of cleaning times is ≥ 1.

3. The method according to claim 1, characterized in that The alkylamine salt is selected from one or more of methylammonium chloride, methylammonium iodide, methylammonium bromide, ethylammonium iodide, ethylammonium bromide and butylammonium bromide.

4. The method according to claim 1, characterized in that The method further comprises: adding phenylethylamine iodide while adding the lead compound additive to obtain a perovskite precursor solution; in the perovskite precursor solution, the concentration of phenylethylamine iodide is 0.5-2 mg / mL.

5. A perovskite film, characterized in that: The perovskite film is prepared by the method according to any one of claims 1 to 4.

6. The perovskite film according to claim 5, characterized in that The perovskite film comprises a perovskite film functional layer and a perovskite film passivation layer.

7. The perovskite film according to claim 6, characterized in that The perovskite film has one or more of the following characteristics: The perovskite film functional layer comprises an ABX3 type perovskite structure material, the A-position cation is selected from one or more of formamidinium ions, cesium ions and methylamine ions, the B-position cation is a lead ion, and the X-position anion is selected from one or more of bromide ions, iodide ions and chloride ions; The thickness of the perovskite thin film functional layer is 400-500nm; The perovskite film passivation layer comprises an alkyl perovskite structure material, the chemical formula of the alkyl perovskite structure material is abx3; in the alkyl perovskite structure material, the a-position cation is selected from CH3(CH2)nNH3 + One or more of, 0≤n≤5, n is an integer, the b-position cation is a lead ion, and the x-position anion is selected from one or more of a bromide ion, an iodide ion or a chloride ion; The thickness of the perovskite film passivation layer is 1-5 nm; The thickness of the perovskite film is 401-505 nm.

8. The perovskite film according to claim 7, characterized in that The CH3(CH2)nNH3 + One or more selected from methylamine ion, ethylamine ion and butylamine ion.

9. A perovskite solar cell, characterized in that: The perovskite solar cell comprises the perovskite thin film according to any one of claims 5 to 8.

10. Use of the perovskite film according to any one of claims 5 to 8 in preparing solar cells.

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