A method for testing stability of perovskite thin film and interface reaction of perovskite thin film

Abstract

The application belongs to the field of photovoltaics, and particularly relates to a testing method for perovskite film stability and perovskite film interface reaction. The testing method for perovskite film stability comprises: performing stability characterization on a perovskite film completely coated with an oxide layer on the surface. The testing method can eliminate the influence of interface stripping and volatilization, test the stability of the perovskite film itself, and then quickly and efficiently screen out stable perovskite structure substances.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of photovoltaics, and particularly relates to a method for testing stability of a perovskite film and interface reaction of the perovskite film. BACKGROUND

[0002] Organic-inorganic hybrid perovskite materials have the material advantages of high absorption coefficient, adjustable band gap, long carrier diffusion length, and high defect tolerance, and the industrial advantages of simple preparation process and low material and preparation cost, and are considered to be the most close-to-commercial new material in the photovoltaic market in recent years. After only a decade of research, single-junction perovskite cells have achieved high photoelectric conversion efficiency, surpassing the currently commercialized cadmium telluride and copper indium gallium selenide cells, and have been very close to the market mainstream crystalline silicon (26.7%) solar cells. Perovskite tandem solar cells have the advantages of high efficiency and low cost, and are considered to be one of the technologies that are expected to realize large-scale ground photovoltaic applications. Perovskite tandem cells have gradually become a hot direction in the field of world photovoltaic research in recent years due to their high efficiency, low cost, and simple preparation process.

[0003] However, the biggest problem of perovskite cells is the stability of the perovskite film itself. A large number of perovskite components will rapidly decay under the action of light and heat, resulting in a significant decrease in device performance, which seriously affects the practical process of perovskite cells. Research on stability will become the core problem of the academic and industrial communities. Finding a light and heat stable perovskite component, and then finding a suitable transport layer material and interface passivation material for it are the core ideas for preparing stable perovskite.

[0004] At present, a recognized cognition is that the stability of perovskite materials itself is the most critical limiting factor for the long-term stability of its devices. However, at present, perovskite also has the problem of reaction failure between the interface transport layer directly connected thereto, and also has the problems of reaction degradation with water in the air and reaction release of organic gas at high temperature, which will be significantly reduced in the perovskite device after encapsulation. Therefore, in the actual research process, these problems are secondary factors, and the most important stability research should focus on the crystal structure change of perovskite under light and heat conditions.

[0005] The existing stability research method is mainly to analyze the surface of the perovskite film exposed, and most of the studies on the bottom surface of the perovskite also have a transport layer, so when the stability of the perovskite film itself is studied, the stability will be limited by the volatilization of the organic salt in the component and the reaction of the perovskite at the interface, at this time, the increase of the perovskite defect and the performance decline of the device cannot be distinguished whether it is the change of the crystal structure of the perovskite layer itself or the change caused by the interface recession, and finally the most stable perovskite component cannot be screened out through experimental methods. The perovskite battery is significantly affected by its interface, and the problems of different transport layer interfaces and electrode interfaces will seriously affect the final stability, and the instability of the perovskite material itself determines the upper limit of the stability of the battery device, and in the actual research process, the stability of the perovskite material itself and the stability of the interface are two parallel stability research directions.

[0006] Therefore, it is urgent to develop a method for testing the stability of the perovskite film itself by stripping the influence of the interface and volatilization, and then quickly and efficiently screening out stable perovskite structure substances. SUMMARY

[0007] To solve the problems existing in the prior art, the present application provides a testing method for a perovskite film. The present application deposits an oxide layer which does not produce a chemical reaction with the perovskite structure substance on the surface of the perovskite film, thereby stripping the possibility of the reaction of the perovskite structure substance with the interface, and the dense oxide layer at the top prevents the volatilization of the organic component in the perovskite structure substance, so that the properties of the perovskite structure substance measured are more reliable compared with the actual packaged device.

[0008] Specifically, the present application provides a testing method for the stability of a perovskite film, which comprises performing stability characterization on a perovskite film whose surface is completely covered by an oxide layer.

[0009] In one or more embodiments, the oxide layer is selected from one or more of silicon oxide, aluminum oxide and tin oxide.

[0010] In one or more embodiments, the thickness of the oxide layer is 1-400 nm.

[0011] In one or more embodiments, the perovskite film comprises a perovskite structure substance, and the chemical formula of the perovskite structure substance is ABX3; A is one or more of monovalent cations, including but not limited to cesium ions, rubidium ions, methylamine ions and formamidine ions; B is one or more of divalent cations, including but not limited to lead ions, copper ions, zinc ions, gallium ions, tin ions and calcium ions; and X is one or more of monovalent anions, including but not limited to iodine ions, bromine ions, chlorine ions, fluorine ions, thiocyanate ions and tetrafluoroborate ions.

[0012] In one or more embodiments, the perovskite thin film has a thickness of 100-5000 nm.

[0013] In one or more embodiments, the perovskite thin film has a substrate at the bottom of the perovskite thin film completely covered by the oxide layer, and the substrate is rough glass, flat glass, a silicon wafer, a mica sheet, quartz, a metal foil, or plastic.

[0014] In one or more embodiments, the method for preparing the perovskite thin film completely covered by the oxide layer comprises: first depositing the oxide layer, then depositing the perovskite thin film on the oxide layer, and then depositing the oxide layer on the perovskite thin film to obtain the perovskite thin film completely covered by the oxide layer.

[0015] In one or more embodiments, the method for depositing the oxide layer is atomic layer deposition, chemical vapor deposition, magnetron sputtering, evaporation, or reactive ion deposition.

[0016] In one or more embodiments, the method for depositing the perovskite thin film comprises: dissolving raw materials of perovskite structure substances in a solvent to obtain a perovskite precursor solution; and coating the perovskite precursor solution on the upper surface of the oxide layer to obtain the perovskite thin film.

[0017] In one or more embodiments, the method for characterizing the stability of the perovskite thin film is X-ray diffraction analysis, X-ray reflectivity analysis, fluorescence analysis, fluorescence quantum yield analysis, optical absorption analysis, or Fourier infrared analysis.

[0018] The present application provides a method for testing the interface reaction of a perovskite thin film, which comprises: characterizing the interface reaction of a composite thin film completely covered by an oxide layer, wherein the composite thin film comprises a perovskite thin film and a first thin film in contact with the perovskite thin film, and the first thin film is a hole transport layer, an interface layer, or an electron transport layer.

[0019] The present application also provides a method for testing the interface reaction of a perovskite thin film, which comprises: characterizing the interface reaction of a semi-covered thin film with the upper surface and sidewall of the perovskite thin film covered by an oxide layer, wherein the semi-covered thin film comprises a perovskite thin film and a hole transport layer in contact with the perovskite thin film.

[0020] In one or more embodiments, the method for characterizing the interface reaction of the perovskite thin film is electron microscope analysis, transmission electron microscope analysis, X-ray diffraction analysis, X-ray reflectivity analysis, fluorescence analysis, fluorescence quantum yield analysis, optical absorption analysis, Fourier infrared analysis, time-of-flight-secondary ion mass spectrometry analysis, or Kelvin probe-atomic force microscope analysis.

[0021] In one or more embodiments, the hole transport layer is selected from one or more of p-type single crystalline silicon, p-type polycrystalline silicon, p-type amorphous silicon, and single molecule self-assembled materials; preferably, the hole transport layer is selected from one or more of [2-(9H-carbazol-9-yl)ethyl]phosphonic acid, [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid, [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid, benzoic acid, 4-[bis(2,4-dimethoxybiphenyl-4-yl)amino]-biphenyl-4-carboxylic acid, 2,2',7,7'-tetrakis[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene, polyethylene terephthalate, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], a polymer of 3-hexylthiophene, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate, 2,2',7,7'-tetrakis(N,N-dip-tolyl)amino-9,9-spirobifluorene, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanodimethyl-p-benzoquinone, 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)benzenamine], antimony-doped tin oxide, NiOx, CuSCN, CuAlO2, V2O5, CdS, and CdSe.

[0022] In one or more embodiments, the hole transport layer has a thickness of 0.1-200 nm.

[0023] In one or more embodiments, the electron transport layer is selected from one or more of n-type single crystalline silicon, n-type polycrystalline silicon, n-type amorphous silicon, TiO2, SnO2, ZnO, ZrO2, Nb x O y , gallium-doped zinc oxide, indium zinc oxide, fluorine-doped tin oxide, indium tin oxide, tungsten-doped indium oxide, BaSnO3, TiSnO x , SnZnO x , C60, fullerene, and fullerene derivatives.

[0024] In one or more embodiments, the electron transport layer has a thickness of 0.1-300 nm.

[0025] In one or more embodiments, the interface layer is selected from one or more of organic-inorganic hybrid two-dimensional perovskite, pure inorganic two-dimensional perovskite, phosphate, and sulfate.

[0026] In one or more embodiments, the interface layer has a thickness of 0.1-300 nm.

[0027] In one or more embodiments, the interface layer is an organic-inorganic hybrid two-dimensional perovskite, and the interface layer has a thickness of 1-200 nm.

[0028] In one or more embodiments, the interface layer is a pure inorganic hybrid two-dimensional perovskite, and the interface layer has a thickness of 1-200 nm.

[0029] In one or more embodiments, the interface layer is a phosphate, and the interface layer has a thickness of 1-20 nm.

[0030] In one or more embodiments, the interface layer is a sulfate, and the interface layer has a thickness of 1-20 nm. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 Structure diagram of a perovskite thin film with a surface-coated oxide layer according to some embodiments of the present application.

[0032] Figure 2 Structure diagram of a perovskite thin film according to Example 1(a), Comparative Example 1(b) and Comparative Example 2(c) of the present application. DETAILED DESCRIPTION

[0033] In order that the present application can be fully understood and readily put into practical effect, there shall be hereinafter described and defined the terms and expressions used in the specification and claims. Unless otherwise defined, all the technical and scientific words used in the specification are of the usual meanings understood by those skilled in the art of the present application, and in case of conflict, the definitions in the specification shall prevail.

[0034] Theories and mechanisms described and disclosed herein, whether correct or not, should not be considered limiting of the scope of the present application, which is defined by the claims. The present application can be implemented in ways other than those specifically set forth herein without departing from the spirit and essential characteristics of the present application.

[0035] In this document, "comprise", "include", "contain", and similar words are used in a inclusive sense and are intended to mean "consist essentially of", and "consist of", for example, when this document discloses that "A comprises B and C", it should be considered that "A consists essentially of B and C" and "A consists of B and C" are also disclosed herein.

[0036] In this document, all features describing a characteristic such as a numerical value, an amount, a content and a concentration in the form of a numerical range or a percentage range are merely for the sake of brevity and convenience. Accordingly, the description of a numerical range or a percentage range should be considered to have encompassed and specifically disclosed all possible sub-ranges and individual numerical values (including integers and fractions) within the range.

[0037] In this document, unless otherwise specified, percentages refer to mass percentages, and ratios refer to mass ratios.

[0038] In the description herein, it is to be understood that the embodiments or examples are not intended to limit the present application to such embodiments or examples. Rather, all alternatives, modifications, and equivalents of the methods and materials described herein, made in the possession of the present application are intended to be within the scope of claims.

[0039] In the description herein, all possible combinations between technical features in various embodiments or examples are not described in order to simplify the description. Therefore, as long as there is no contradiction in the combination of technical features, any combination of technical features in various embodiments or examples can be combined, and all possible combinations should be considered as the scope described in the specification.

[0040] The present application provides a test method for perovskite thin film, which comprises stability characterization of perovskite thin film completely coated with an oxide layer on the surface. In the present application, a dense oxide layer which does not react with perovskite structure material is coated on the surface of perovskite thin film, the oxide layer completely covers all surfaces of perovskite thin film, which is isolated from air, the possibility of interface reaction of perovskite structure material is removed, and the volatilization of organic components in perovskite structure material is prevented. The perovskite thin film coated with an oxide layer on the surface is used for aging under light, heat, etc., and the characteristics of perovskite structure material measured are more reliable than those of actual packaged devices.

[0041] In the present application, the perovskite thin film completely coated with an oxide layer on the surface is the characterization object of perovskite thin film.

[0042] In the present application, the oxide layer can be one or more selected from silicon oxide, aluminum oxide and tin oxide. In the present application, the surface and sidewall of perovskite thin film are completely encapsulated and wrapped by a dense oxide layer which does not react with halogen ions, amine ions and amidine ions in perovskite material, which well blocks the penetration and damage of water vapor and oxygen in the air to perovskite thin film, and the material does not react with migrated halogen ions in perovskite to induce degradation of the thin film. This method can be used to study the stability of perovskite thin film material, including the influence of perovskite components and film crystallization quality on stability. Further, some functional layers are introduced into perovskite thin film, and the surface and sidewall of perovskite thin film are completely encapsulated and wrapped by a dense inorganic oxide material, and then the photoelectric properties of the composite film are characterized, which can further analyze the influence of interface reaction on material characteristics.

[0043] In the present application, the thickness of the oxide layer can be 1-400 nm, for example, 1 nm, 5 nm, 10 nm, 20 nm, 30 nm, 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm. In the present application, the thickness of the oxide layer is controlled in the above range, which is beneficial to test the performance of perovskite thin film.

[0044] In the present application, the oxide layers covering the upper surface, lower surface and sidewall of the perovskite thin film can be the same or different.

[0045] In the present application, the perovskite thin film can comprise perovskite structure material, the chemical formula of the perovskite structure material can be ABX3, A can be one or more of monovalent cations, which can include but not limited to cesium ion (Cs + ), rubidium ion (Rb + ), methylamine ion (CH3NH3 + , MA) and formamidinium ion (CH(NH2)2 + , FA); B can be one or more of divalent cations, which can include but not limited to lead ion (Pb 2+ ), copper ion (Cu 2+ ), zinc ion (Zn 2+ ), gallium ion (Ga 2+ ), tin ion (Sn 2+ ) and calcium ion (Ca 2+ ); X can be one or more of monovalent anions, which can include but not limited to iodine ion (I - ), bromine ion (Br - ), chlorine ion (Cl - ), fluorine ion (F - ), thiocyanate ion (SCN - ), tetrafluoroborate ion (BF4 - ) and hexafluorophosphate ion (PF6 - ).

[0046] In the present application, the thickness of the perovskite thin film can be 100-5000 nm, for example, 100 nm, 500 nm, 1000 nm, 2000 nm, 2500 nm, 3000 nm, 3500 nm, 4000 nm, 4500 nm, 5000 nm.

[0047] In the present application, the bottom of the perovskite thin film whose surface is completely covered by the oxide layer can also have a substrate, which can be rough glass, flat glass, silicon wafer, mica sheet, quartz, metal foil or plastic.

[0048] In the present application, the preparation method of the perovskite thin film whose surface is completely covered by the metal oxide layer comprises: first depositing an oxide layer, depositing a perovskite thin film on the oxide layer, and then depositing an oxide layer on the perovskite thin film to obtain a perovskite thin film whose surface is completely covered by the oxide layer.

[0049] In the present application, the preparation method of the perovskite thin film whose surface is completely covered by the metal oxide layer further comprises: first depositing an oxide layer on the surface of the substrate.

[0050] In the present application, the deposition method of the oxide layer can be atomic layer deposition (ALD), chemical vapor deposition (CVD), magnetron sputtering, evaporation, or reactive ion deposition (RPD).

[0051] In the present application, the deposition method of the perovskite thin film includes dissolving raw materials of perovskite structure substances in a solvent to obtain a perovskite precursor solution, and coating the perovskite precursor solution on the upper surface of the oxide layer to obtain a perovskite thin film.

[0052] In the present application, the method for characterizing the stability of the perovskite thin film completely covered by the metal oxide layer can be X-ray diffraction analysis, X-ray reflection analysis, fluorescence analysis, fluorescence quantum yield analysis, optical absorption analysis, or Fourier infrared analysis. In some embodiments, the fluorescence analysis can be photoluminescence analysis (PL).

[0053] The present application can also be used to study electron extraction kinetics or hole extraction kinetics.

[0054] The present application also provides a test method for interface reaction of a perovskite thin film, which includes characterizing the interface reaction of a composite thin film completely covered by an oxide layer, the composite thin film including a perovskite thin film and a first thin film in contact with the perovskite thin film, the first thin film being a hole transport layer, an interface layer, or an electron transport layer.

[0055] The present application also provides a test method for interface reaction of a perovskite thin film, which includes characterizing the interface reaction of a semi-covered thin film with the upper surface and sidewall of the perovskite thin film covered by an oxide layer, the semi-covered thin film including a perovskite thin film and a hole transport layer in contact with the perovskite thin film.

[0056] In the present application, the characterization method for interface reaction of a perovskite thin film can be electron microscopy analysis, transmission electron microscopy analysis, X-ray diffraction analysis, X-ray reflection analysis, fluorescence analysis, fluorescence quantum yield analysis, optical absorption analysis, Fourier infrared analysis, time-of-flight-secondary ion mass spectrometry analysis, or Kelvin probe-atomic force microscopy analysis.

[0057] In the present invention, the hole transport layer can be one or more selected from p-type single crystalline silicon, p-type polycrystalline silicon, p-type amorphous silicon, and a single molecule self-assembly material; preferably, the hole transport layer can be one or more selected from [2-(9H-carbazol-9-yl)ethyl]phosphonic acid (2PACz), [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid (MeO-2PACz), [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACz), benzoic acid, 4-[bis(2,4-dimethoxybiphenyl-4-yl)amino]-biphenyl-4-carboxylic acid [MC-43], 2,2',7,7'-tetrakis[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Sprio-OMeTAD), polyethylene terephthalate (PET), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), a polymer of 3-hexylthiophene (P3HT), poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PSS), 2,2',7,7'-tetrakis(N,N-di-p-tolyl)amino-9,9-spirobifluorene (Spiro-TTB), 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ), 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanodimethoxy-p-benzoquinone (F6TCNNQ), 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)benzenamine] (TAPC), antimony-doped tin oxide (ATO), NiOx, CuSCN, CuAlO2, V2O5, CdS, and CdSe. In the present invention, the thickness of the hole transport layer can be 0.1-200 nm, for example, 0.5 nm, 1 nm, 5 nm, 10 nm, 20 nm, 30 nm, 50 nm, 100 nm, 150 nm, 200 nm.

[0058] In the present invention, the electron transport layer can be one or more selected from n-type single crystalline silicon, n-type polycrystalline silicon, n-type amorphous silicon, TiO2, SnO2, ZnO, ZrO2, Nb x O y , gallium-doped zinc oxide (GZO), indium-zinc oxide (IZO), fluorine-doped tin oxide (FTO), indium tin oxide (ITO), tungsten-doped indium oxide (IWO), BaSnO3, TiSnO x , SnZnO x , C60, fullerene, and a fullerene derivative. In the present invention, the thickness of the electron transport layer can be 0.1-300 nm, for example, 0.5 nm, 1 nm, 5 nm, 10 nm, 20 nm, 30 nm, 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm.

[0059] In the present application, the interface layer can be one or more selected from the group consisting of an organic-inorganic hybrid two-dimensional perovskite, a pure inorganic two-dimensional perovskite, a phosphate, and a sulfate. In some embodiments, the phosphate is lead phosphate; in some embodiments, the sulfate is lead sulfate.

[0060] In the present application, the thickness of the interface layer can be 0.1-300 nm, for example, 0.5 nm, 1 nm, 5 nm, 10 nm, 20 nm, 30 nm, 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm. In some embodiments, when the interface layer is an organic-inorganic hybrid two-dimensional perovskite, the thickness of the interface layer can be 1-200 nm, for example, 1 nm, 5 nm, 10 nm, 20 nm, 30 nm, 50 nm, 100 nm, 150 nm, 200 nm. In some embodiments, when the interface layer is a pure inorganic hybrid two-dimensional perovskite, the thickness of the interface layer can be 1-200 nm, for example, 1 nm, 5 nm, 10 nm, 20 nm, 30 nm, 50 nm, 100 nm, 150 nm, 200 nm. In some embodiments, when the interface layer is a phosphate, the thickness of the interface layer can be 1-20 nm, for example, 2 nm, 4 nm, 6 nm, 8 nm, 10 nm, 12 nm, 14 nm, 16 nm, 18 nm, 20 nm. In some embodiments, when the interface layer is a sulfate, the thickness of the interface layer can be 1-20 nm, for example, 2 nm, 4 nm, 6 nm, 8 nm, 10 nm, 12 nm, 14 nm, 16 nm, 18 nm, 20 nm.

[0061] Compared with the prior art, the present application has the following beneficial effects:

[0062] (1) In the present application, the surface oxide layer of the perovskite thin film completely covers all surfaces of the perovskite thin film, isolating it from the air and eliminating the possibility of interface reaction of the perovskite structure material, preventing the volatilization of the organic component in the perovskite structure material. The perovskite thin film with the surface oxide layer is used for aging under light, heat, etc., and the measured properties of the perovskite structure material are more reliable than those of the actual packaged device.

[0063] (2) The present application can quickly and efficiently screen out stable perovskite components, which is suitable for perovskite enterprises to develop stable perovskite components.

[0064] (3) The test method of the present application can not only be used for small flux experimental design, but also can be combined with high flux to screen and study materials.

[0065] The present application will be described below in the manner of specific examples. It should be understood that these examples are merely illustrative and are not intended to limit the scope of the present application. The methods, reagents and materials used in the examples are conventional in the art unless otherwise specified. The starting compounds in the examples can be purchased through commercially available routes.

[0066] Example 1

[0067] The perovskite thin film interface reaction characterization object was prepared in this example, and the specific steps were as follows: Figure 2 (a) The perovskite thin film characterization object was prepared as shown below:

[0068] (1) A 20 nm thick silicon dioxide film was deposited on a clean ITO glass substrate using CVD to obtain an oxide layer;

[0069] (2) A perovskite precursor solution was coated on the upper surface of the oxide layer using a slot coating method to obtain a perovskite thin film with a thickness of 1000 nm; wherein the solute of the perovskite precursor solution was FA 0.8 Cs 0.2 PbI3(FACs), and the solvent of the perovskite precursor solution was a mixed solvent of DMF and DMSO with a volume ratio of 4:1, and the concentration of the solute in the perovskite precursor solution was 1.7 mol / L;

[0070] (3) A 200 nm thick aluminum oxide layer was deposited on the upper surface and sidewall of the perovskite thin film using ALD to obtain an oxide layer, and at the same time, the perovskite thin film characterization object was obtained.

[0071] Example 2

[0072] The perovskite thin film interface reaction characterization object was prepared in this example, and the specific steps were as follows:

[0073] (1) A 20 nm thick nickel oxide film was deposited on a clean ITO glass substrate using magnetron sputtering to obtain a hole transport layer;

[0074] (2) A perovskite precursor solution was coated on the upper surface of the hole transport layer using a slot coating method to obtain a perovskite thin film with a thickness of 1000 nm; wherein the solute of the perovskite precursor solution was FA 0.8 Cs 0.2 PbI3(FACs), and the solvent of the perovskite precursor solution was a mixed solvent of DMF and DMSO with a volume ratio of 4:1, and the concentration of the solute in the perovskite precursor solution was 1.7 mol / L;

[0075] (3) A 200 nm thick aluminum oxide layer was deposited on the upper surface and sidewall of the perovskite thin film using ALD to obtain an oxide layer, and at the same time, the perovskite thin film characterization object was obtained.

[0076] Example 3

[0077] This embodiment prepares a perovskite thin film interface reaction characterization object, and the specific steps are as follows:

[0078] (1) A 20 nm thick silicon dioxide film is deposited on a clean ITO glass substrate using a CVD method to obtain an oxide layer;

[0079] (2) A perovskite precursor solution is coated on the upper surface of the oxide layer using a slot coating method to obtain a perovskite thin film with a thickness of 1000 nm; wherein the solute of the perovskite precursor solution is FA 0.8 Cs 0.2 PbI3(FACs), the solvent of the perovskite precursor solution is a mixed solvent of DMF and DMSO, the volume ratio of the solvent is 4:1, and the concentration of the solute in the perovskite precursor solution is 1.7 mol / L;

[0080] (3) A 2 mg / mL phenethylamine iodide (PEAI) is coated on the surface of the perovskite thin film to obtain an interface layer with a material of organic-inorganic hybrid two-dimensional perovskite and a thickness of 2 nm;

[0081] (4) A 200 nm thick aluminum oxide is deposited on the upper surface of the interface layer, the interface layer and the sidewall of the perovskite thin film using an ALD method to obtain an oxide layer, and at the same time, a perovskite thin film characterization object is obtained.

[0082] Example 4

[0083] This embodiment prepares a perovskite thin film interface reaction characterization object, and the specific steps are as follows:

[0084] (1) A 20 nm thick silicon dioxide film is deposited on a clean ITO glass substrate using a CVD method to obtain an oxide layer;

[0085] (2) A perovskite precursor solution is coated on the upper surface of the oxide layer using a slot coating method to obtain a perovskite thin film with a thickness of 1000 nm; wherein the solute of the perovskite precursor solution is FA 0.8 Cs 0.2 PbI3(FACs), the solvent of the perovskite precursor solution is a mixed solvent of DMF and DMSO, the volume ratio of the solvent is 4:1, and the concentration of the solute in the perovskite precursor solution is 1.7 mol / L;

[0086] (3) A 15 nm thick C60 material is prepared on the surface of the perovskite thin film using a thermal evaporation method to obtain an electron transport layer;

[0087] (4) ALD method is used to deposit a layer of 200 nm of aluminum oxide on the upper surface of the electron transport layer, the side wall of the electron transport layer and the perovskite film to obtain an oxide layer, and at the same time obtain the perovskite film characterization object.

[0088] Comparative Example 1

[0089] The perovskite film characterization object shown in (a) is prepared as follows: Figure 2 (b) The perovskite film characterization object shown in (a) is prepared as follows:

[0090] (1) A perovskite precursor solution is coated on a clean ITO glass substrate by using a slot coating method to obtain a perovskite film with a thickness of 1000 nm, and at the same time obtain the perovskite film characterization object; wherein the solute of the perovskite precursor solution is FA 0.8 Cs 0.2 PbI3(FACs), the solvent of the perovskite precursor solution is a mixed solvent of DMF and DMSO, the volume ratio of the solvents is 4:1, and the concentration of the solute in the perovskite precursor solution is 1.7 mol / L.

[0091] Comparative Example 2

[0092] The perovskite film characterization object shown in (c) is prepared as follows: Figure 2 (c) The perovskite film characterization object shown in (a) is prepared as follows:

[0093] (1) A perovskite precursor solution is coated on a clean ITO glass substrate by using a slot coating method to obtain a perovskite film with a thickness of 1000 nm; wherein the solute of the perovskite precursor solution is FA 0.8 Cs 0.2 PbI3(FACs), the solvent of the perovskite precursor solution is a mixed solvent of DMF and DMSO, the volume ratio of the solvents is 4:1, and the concentration of the solute in the perovskite precursor solution is 1.7 mol / L.

[0094] (2) ALD method is used to deposit a layer of 200 nm of aluminum oxide on the upper surface and the side wall of the perovskite film to obtain an oxide layer, and at the same time obtain the perovskite film characterization object.

[0095] Test Example 1

[0096] The perovskite film characterization objects prepared in Examples 1-4 and Comparative Examples 1-2 are subjected to PL test and XRD test after 500 h of AM 1.5 light illumination at 85°C, and the test results are shown in Table 1.

[0097] PL test: the fluorescence excitation light wavelength is 450 nm, the intensity is 100 mW / cm 2 , the detector is a CCD detector, and the detector integration time is 2000 ms.

[0098] XRD test: the ratio of lead iodide to perovskite is obtained by integrating the area of the peak at 2 theta angle of 12.7° representing lead iodide and the area of the peak at 2 theta angle of 14.5° representing perovskite.

[0099] Table 1: PL intensity and lead iodide / perovskite ratio of perovskite thin film characterization objects prepared in Example 1, Comparative Example 1 and Comparative Example 2

[0100]

[0101]

[0102] The decrease of fluorescence intensity represents the increase of non-radiative recombination in perovskite thin film, which is a direct manifestation of the decline of photoelectric performance of perovskite material. The change of phase represented by XRD is the product after decomposition of perovskite material, and the greater the ratio of lead iodide to perovskite, the more decomposition of perovskite material.

[0103] As can be seen from Table 1, the PL intensity of the perovskite thin film characterization object prepared in Example 1 is greater than that of the perovskite thin film characterization objects prepared in Comparative Example 1 and Comparative Example 2, and the lead iodide / perovskite ratio of the perovskite thin film characterization object prepared in Example 1 is less than that of the perovskite thin film characterization objects prepared in Comparative Example 1 and Comparative Example 2, which indicates that the decomposition rate of perovskite material in Comparative Example 1 and Comparative Example 2 is significantly faster than that of perovskite material in Example 1, and the stability of perovskite material in Example 1 is significantly higher than that of perovskite material in Comparative Example 1 and Comparative Example 2, which indicates that the contact interface between the substrate and the perovskite thin film and the contact between the surface of the perovskite thin film and the external environment significantly improves the degradation rate of perovskite material. The perovskite thin film stability test method of the present application avoids these situations, and the test results are more accurate.

[0104] As can be seen from Table 1, the comparison between Example 2 and Example 1 shows that the hole transport layer NiOx significantly induces the decline of photoelectric performance of perovskite device, and the lead iodide ratio is also higher, which indicates that the existence of NiOx interface accelerates the decomposition of perovskite. As can be seen from the results of Example 3 and Example 1, the organic-inorganic hybrid two-dimensional perovskite interface layer does not react with perovskite, and the existence of this layer will not accelerate the aging and attenuation of perovskite. As can be seen from the comparison between Example 4 and Example 1, the existence of C60 will greatly accelerate the aging and decomposition of perovskite thin film.

Claims

1. A method for testing the stability of a perovskite thin film, characterized by, The test method comprises stability characterization of the perovskite thin film completely coated with the oxide layer on the surface. The preparation method of the perovskite thin film completely coated with the oxide layer on the surface comprises the following steps: firstly depositing the oxide layer, depositing the perovskite thin film on the oxide layer, and then depositing the oxide layer on the perovskite thin film to obtain the perovskite thin film completely coated with the oxide layer on the surface. The bottom of the perovskite thin film completely coated with the oxide layer on the surface is provided with a substrate, and the substrate is rough glass, flat glass, a silicon wafer, a mica sheet, quartz, a metal foil or plastic. The oxide layer is silicon oxide and / or aluminum oxide.

2. The test method of claim 1, wherein, The test method has one or more of the following characteristics: The thickness of the oxide layer is 1-400 nm. The perovskite thin film comprises perovskite structure material, and the chemical formula of the perovskite structure material is ABX3; A is a monovalent cation selected from one or more of cesium ions, rubidium ions, methylamine ions and formamidinium ions; B is a divalent cation selected from one or more of lead ions, copper ions, zinc ions, gallium ions, tin ions and calcium ions; and X is a monovalent anion selected from one or more of iodine ions, bromine ions, chlorine ions, fluorine ions, thiocyanate ions and tetrafluoroborate ions. The thickness of the perovskite thin film is 100-5000 nm.

3. The test method of claim 1, wherein, The deposition method of the oxide layer is atomic layer deposition, chemical vapor deposition, magnetron sputtering, evaporation or reactive ion deposition.

4. The test method of claim 1, wherein, The deposition method of the perovskite thin film comprises the following steps: dissolving raw materials of the perovskite structure material in a solvent to obtain a perovskite precursor solution; and coating the perovskite precursor solution on the upper surface of the oxide layer to obtain the perovskite thin film.

5. The test method of claim 1, wherein, The characterization method of the stability of the perovskite thin film is X-ray diffraction analysis, X-ray reflection analysis, fluorescence analysis, fluorescence quantum yield analysis, optical absorption analysis or Fourier infrared analysis.

6. A method of testing perovskite thin film interface reactions, characterized by, The test method comprises: interface reaction characterization of a composite thin film completely coated with an oxide layer on the surface, wherein the composite thin film comprises a perovskite thin film and a first thin film in contact with the perovskite thin film, and the first thin film is a hole transport layer, an interface layer or an electron transport layer; or interface reaction characterization of a semi-coated thin film with the upper surface and the sidewall of the perovskite thin film coated with an oxide layer, wherein the semi-coated thin film comprises a perovskite thin film and a hole transport layer in contact with the perovskite thin film; (1) depositing a 20 nm-thick nickel oxide film on a clean ITO glass substrate by using a magnetron sputtering method to obtain a hole transport layer; (2) coating a perovskite precursor solution on the upper surface of the hole transport layer by using a slot coating method to obtain a perovskite film with a thickness of 1000 nm; wherein the solute of the perovskite precursor solution is FA 0.8 Cs 0.2 PbI3(FACs), the solvent of the perovskite precursor solution is a mixed solvent of DMF and DMSO, the volume ratio of the solvents is 4:1, and the concentration of the solute in the perovskite precursor solution is 1.7 mol / L; (3) depositing a 200 nm-thick aluminum oxide on the upper surface and sidewall of the perovskite film by using an ALD method to obtain an oxide layer, and simultaneously obtaining a perovskite film characterization object; or (1') depositing a 20 nm-thick silicon dioxide film on a clean ITO glass substrate by CVD to obtain an oxide layer; (2') coating a perovskite precursor solution on the upper surface of the oxide layer by a slot coating method to obtain a perovskite film with a thickness of 1000 nm; wherein the solute of the perovskite precursor solution is FA 0.8 Cs 0.2 PbI3(FACs), the solvent of the perovskite precursor solution is a mixed solvent of DMF and DMSO, the volume ratio of the solvents is 4:1, and the concentration of the solute in the perovskite precursor solution is 1.7 mol / L; (3') coating phenethylammonium iodide (PEAI) with a concentration of 2 mg / mL on the surface of the perovskite film to obtain an interface layer with a material of organic-inorganic hybrid two-dimensional perovskite and a thickness of 2 nm; (4') depositing a 200 nm-thick aluminum oxide on the upper surface of the interface layer, the interface layer and the sidewall of the perovskite film by ALD to obtain an oxide layer, and meanwhile obtaining a perovskite film characterization object; or (1) depositing a 20 nm-thick silicon dioxide film on a clean ITO glass substrate by CVD to obtain an oxide layer; (2) coating a perovskite precursor solution on the upper surface of the oxide layer by slot coating to obtain a perovskite film with a thickness of 1000 nm; wherein the solute of the perovskite precursor solution is FA 0.8 Cs 0.2 PbI3(FACs), the solvent of the perovskite precursor solution is a mixed solvent of DMF and DMSO, the volume ratio of the solvents is 4:1, and the concentration of the solute in the perovskite precursor solution is 1.7 mol / L; (3) preparing a 15 nm-thick C60 material on the surface of the perovskite film by thermal evaporation to obtain an electron transport layer; (4) depositing a 200 nm-thick aluminum oxide on the upper surface of the electron transport layer and the sidewalls of the electron transport layer and the perovskite film by ALD to obtain an oxide layer, and meanwhile obtaining a perovskite film characterization object.

7. The test method of claim 6, wherein, The characterization method of the interface reaction of the perovskite thin film is electron microscope analysis, transmission electron microscope analysis, X-ray diffraction analysis, X-ray reflection analysis, fluorescence analysis, fluorescence quantum yield analysis, optical absorption analysis, Fourier infrared analysis, time-of-flight-secondary ion mass spectrometry analysis or Kelvin probe-atomic force microscope analysis.

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