Perovskite precursor solution, perovskite precursor film and perovskite crystallization regulation and control method

Abstract

The invention provides a perovskite precursor solution, a perovskite precursor film and a perovskite crystallization regulation method. The perovskite precursor solution contains a perovskite active material, an additive and a solvent; the perovskite active material is a perovskite active material which does not contain methylamino; the additive is a compound as shown in a formula A. According to the method, the compound with carboxyl and hydroxyl functional groups is selected as the additive to prepare the perovskite thin film, the crystallization kinetics process of perovskite is improved, the thin film with larger grain size and fewer grain boundaries can be obtained, the quality of the thin film is improved, and then the photoelectric conversion efficiency and stability of the solar cell are improved.

Description

Technical Field

[0001] The present invention relates to the field of perovskite solar cells, and in particular to a perovskite precursor solution, a film thereof and a perovskite crystallization control method. Background Art

[0002] With the rapid development of photovoltaic technology, perovskite solar cells have attracted much attention due to their high photoelectric conversion efficiency and low-cost preparation process. However, traditional methylamine (MA)-based perovskite materials have problems such as poor stability and sensitivity to temperature, humidity and oxygen, which limit their commercial application. To solve these problems, researchers turned their attention to formamidine (FA)-based and other methylamine-free perovskite materials. However, the crystallization process of FA-based perovskites is difficult to control, and methylamine-free perovskites also face the challenge of difficult to control nucleation and crystallization rates during the preparation process, resulting in poor film quality and affecting device performance.

[0003] During the preparation process of methylamine-free perovskite, its nucleation and crystallization rates are difficult to control. This is mainly because the nucleation rate of perovskite or perovskite solvent complex phase may be too slow, resulting in the formation of dendrites after spontaneous desolvation in saturated solution, making it difficult to form a dense film. Summary of the invention

[0004] In view of the problems that the nucleation and crystallization rates of methylamine-free perovskite films in the prior art are difficult to control during the preparation process, resulting in poor film quality, the present invention provides a perovskite precursor solution, a film thereof, and a perovskite crystallization control method. The present invention selects compounds with carboxyl and hydroxyl functional groups as additives to prepare perovskite films, improves the crystallization kinetics of perovskites, and can obtain films with larger grain sizes and fewer grain boundaries, thereby improving film quality and thereby improving the photoelectric conversion efficiency and stability of solar cells.

[0005] Specifically, the first aspect of the present invention provides a perovskite precursor solution, wherein the perovskite precursor solution contains a perovskite active material, an additive and a solvent; the perovskite active material is a perovskite active material that does not contain a methylamine group; and the additive is a compound of formula A:

[0006]

[0007] wherein R1 and R2 are each independently hydroxyl, hydroxyl-substituted alkyl, carboxyl, carboxyl-substituted alkyl, hydroxyl and carboxyl-substituted alkyl.

[0008] In one or more embodiments, R1 and R2 are the same or different.

[0009] In one or more embodiments, R1 and R2 are para, meta, or ortho.

[0010] In one or more embodiments, the hydroxy-substituted alkyl group contains only one hydroxy group.

[0011] In one or more embodiments, the carboxyl-substituted alkyl group contains only one carboxyl group;

[0012] In one or more embodiments, the hydroxy and carboxyl substituted alkyl groups contain only one hydroxy and carboxyl group.

[0013] In one or more embodiments, the alkyl group is C 1-10 Straight chain alkyl or C 1-10 Branched chain alkyl, such as C 1-5 Straight chain alkyl or C 1-5 Branched chain alkyl.

[0014] In one or more embodiments, R1 contains only one hydroxyl group and R2 contains only one carboxyl group. Alternatively, in one or more embodiments, R2 contains only one hydroxyl group and R1 contains only one carboxyl group.

[0015] In one or more embodiments, the additive includes one or more of p-hydroxybenzoic acid, m-hydroxybenzoic acid, and o-hydroxybenzoic acid.

[0016] In one or more embodiments, the perovskite active material is an ABX3 compound, A is FA + and / or Cs + ; B is Pb 2+ and / or Sn 2+ ; X is 1 - Br - and Cl - One of many.

[0017] In one or more embodiments, the molar concentration of the perovskite active material in the perovskite precursor solution is 1-1.8 mol / L.

[0018] In one or more embodiments, the molar concentration of the additive in the perovskite precursor solution is 0.01-0.18 mol / L.

[0019] In one or more embodiments, the molar ratio of the additive to the perovskite active material in the perovskite precursor solution is (0.01-0.1):1.

[0020] In one or more embodiments, the solvent is selected from one or more of N,N-dimethylformamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, γ-butyrolactone, 1,3-dimethyl-2-imidazolidinone, dimethylacetamide, N,N-dimethylpropyleneurea, acetonitrile or 2-mercaptoethanol.

[0021] The second aspect of the present invention provides a method for regulating the crystallization of methylamine-free perovskite or preparing a methylamine-free perovskite film, the method comprising the following steps: coating a perovskite precursor solution as described in any embodiment of the present invention on a substrate layer, annealing, and obtaining the perovskite film.

[0022] In one or more embodiments, the coating method is one or more of spin coating, slit coating, doctor blading, screen printing and inkjet printing.

[0023] In one or more embodiments, the substrate layer is a hole transport layer or an electron transport layer.

[0024] In one or more embodiments, the annealing temperature is 100-180° C., and the annealing time is 5-60 min.

[0025] In one or more embodiments, the perovskite film has a thickness of 400-800 nm.

[0026] The third aspect of the present invention provides a perovskite film, which contains a perovskite active material and an additive, wherein the perovskite active material is a perovskite active material that does not contain a methylamine group; and the additive is a compound of formula A as described in any embodiment of the present invention.

[0027] In one or more embodiments, the perovskite active material is an ABX3 compound, A is FA + and / or Cs + ; B is Pb 2+ and / or Sn 2+ ; X is 1 - Br - and Cl - One of many.

[0028] In one or more embodiments, the molar concentration of the perovskite active material in the perovskite precursor solution is 1-1.8 mol / L.

[0029] In one or more embodiments, the molar concentration of the additive in the perovskite precursor solution is 0.01-0.18 mol / L.

[0030] In one or more embodiments, the molar ratio of the additive to the perovskite active material in the perovskite precursor solution is (0.01-0.1):1.

[0031] In one or more embodiments, the perovskite film is prepared by the method for preparing a perovskite film as described in any embodiment of the present invention.

[0032] A fourth aspect of the present invention provides a perovskite solar cell, which comprises a conductive substrate layer, a hole transport layer, a perovskite film as described in any embodiment of the present invention, an electron transport layer, a blocking layer and an electrode.

[0033] The fifth aspect of the present invention provides the use of an additive in controlling the crystallization rate and morphology of methylamine-free perovskite, wherein the additive is a compound of formula A as described in any embodiment of the present invention. Preferably, the additive comprises one or more of p-hydroxybenzoic acid, m-hydroxybenzoic acid and o-hydroxybenzoic acid.

[0034] The sixth aspect of the present invention provides the use of an additive in preparing a perovskite film with increased grain size and reduced grain boundaries, wherein the additive is a compound of formula A as described in any embodiment of the present invention. Preferably, the additive comprises one or more of p-hydroxybenzoic acid, m-hydroxybenzoic acid and o-hydroxybenzoic acid.

[0035] A seventh aspect of the present invention provides the use of a perovskite precursor solution as described in any embodiment of the present invention in the preparation of a perovskite film with increased grain size and reduced grain boundaries.

[0036] An eighth aspect of the present invention provides the use of a perovskite precursor solution as described in any embodiment herein in the preparation of a perovskite solar cell with improved photoelectric conversion efficiency and stability.

[0037] Beneficial effects of the present invention:

[0038] 1) The present invention selects an additive containing hydroxyl and carboxyl functional groups. The two functional groups have a synergistic effect. The hydroxyl and carboxyl groups in the additive can react with the Pb in the perovskite precursor solution. 2 + or Sn 2+ Interact with each other to form hydrogen bonds or weak coordination bonds. 2 + or Sn 2+ The interaction between the additives can slow down the crystallization rate of methylamine-free perovskite, providing more time for the grains to grow and align. By adjusting the concentration and type of additives, the crystallization rate and morphology of the perovskite can be precisely controlled, resulting in high-quality films with larger grain sizes and fewer grain boundaries. High-quality films help improve the photoelectric conversion efficiency and stability of solar cells and reduce performance degradation caused by film defects.

[0039] 2) The method of the present invention is easy to operate, and the selected additive contains both hydroxyl and carboxyl groups. The two functional groups work synergistically, complement each other's advantages, and work together to more accurately control the perovskite crystallization process and prepare high-quality methylamine-free perovskite films. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 The present invention is a flow chart of the method for preparing an inverse perovskite solar cell.

[0041] Figure 2 The crystal morphology diagrams of the perovskite films of the experimental group and the control group of the present invention. DETAILED DESCRIPTION

[0042] 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 this article. Unless otherwise specified, all technical and scientific terms used in this article are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definitions in this article shall prevail.

[0043] 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.

[0044] 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.

[0045] 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).

[0046] In this document, unless otherwise specified, percentage refers to mass percentage and ratio refers to mass ratio.

[0047] 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.

[0048] 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.

[0049] The purpose of the present invention is to provide a perovskite precursor solution, a film thereof and a method for controlling perovskite crystallization. The nucleation and crystallization rates of methylamine-free perovskite films are difficult to control during the preparation process, resulting in poor film quality. The inventors of the present invention have found that a compound having carboxyl and hydroxyl functional groups is selected as an additive. The carboxyl and hydroxyl groups in the additive can react with Pb in the perovskite precursor solution. 2 + or Sn 2+ Interact with each other to form hydrogen bonds or weak coordination bonds. 2 + or Sn 2+ The interaction between the additives can slow down the crystallization rate of perovskite, providing more time for the grains to grow and align. By adjusting the concentration and type of additives, the crystallization rate and morphology of perovskite can be precisely controlled, resulting in high-quality films with larger grain sizes and fewer grain boundaries. High-quality films help improve the photoelectric conversion efficiency and stability of solar cells and reduce performance degradation caused by film defects.

[0050] In the present invention, the additive is a compound of formula A:

[0051]

[0052] wherein R1 and R2 are each independently a hydroxyl group, an alkyl group substituted with a hydroxyl group, a carboxyl group, an alkyl group substituted with a carboxyl group, or an alkyl group substituted with a hydroxyl group and a carboxyl group.

[0053] In some embodiments, the alkyl group is C 1-10 Straight chain alkyl or C 1-10 Branched chain alkyl, such as C 1-5 Straight chain alkyl or C 1-5 Branched chain alkyl.

[0054] In some embodiments, when R1 contains a hydroxyl group, R2 contains a carboxyl group. Alternatively, when R2 contains a hydroxyl group, R1 contains a carboxyl group.

[0055] In some embodiments, the hydroxy-substituted alkyl group contains only one hydroxy group.

[0056] In some embodiments, the carboxy-substituted alkyl group contains only one carboxy group.

[0057] In some embodiments, the hydroxy and carboxyl substituted alkyl groups contain only one hydroxy and carboxyl group.

[0058] In some embodiments, the compound of formula A is p-hydroxybenzoic acid, o-hydroxybenzoic acid, or m-hydroxybenzoic acid.

[0059] In some embodiments, the additive includes one or more of p-hydroxybenzoic acid, m-hydroxybenzoic acid, and o-hydroxybenzoic acid.

[0060] In the present invention, the perovskite active material in the perovskite precursor solution is a perovskite active material that does not contain a methylamine group. In some embodiments, the perovskite active material is an ABX3 compound, where A is FA + and / or Cs + ; B is Pb 2+ and / or Sn 2 + ; X is 1 - Br - and Cl - In some embodiments, A is FA + and Cs + , B is Pb 2+ , X is I - In some embodiments, the perovskite active material is FA 0.9 Cs 0.1 PbI3.

[0061] In some embodiments, in the perovskite precursor solution, the molar ratio of the additive to the perovskite active material is (0.01-0.1):1; such as 0.02-0.04.

[0062] In some embodiments, the molar concentration of the perovskite active material in the perovskite precursor solution is 1-1.8 mol / L, such as 1-1.3 mol / L.

[0063] In some embodiments, in the perovskite precursor solution, the molar concentration of the additive is 0.01-0.18 mol / L, such as 0.1-0.04 mol / L.

[0064] The perovskite thin film of the present invention can be obtained by coating a perovskite precursor solution containing the above-mentioned perovskite active material and additives on the surface of a substrate layer and annealing.

[0065] In some embodiments, the method for preparing the perovskite film of the present invention comprises the following steps:

[0066] S1. preparing a perovskite precursor solution: mixing a perovskite active material, an additive and a solvent to obtain the perovskite precursor solution;

[0067] S2. Coating the perovskite passivation precursor solution on the surface of the substrate layer by a solution method, and annealing to obtain a perovskite film.

[0068] In step S1, the solvent can be selected from one or more of N,N-dimethylformamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, γ-butyrolactone, 1,3-dimethyl-2-imidazolidinone, dimethylacetamide, N,N-dimethylpropyleneurea, acetonitrile or 2-mercaptoethanol.

[0069] In step S2, the coating method can be one or more of spin coating, slit coating, doctor blading, screen printing and inkjet printing. The coating thickness and coating rate of the perovskite passivation precursor solution can be adjusted according to the target thickness of the perovskite film.

[0070] In step S2, the perovskite passivation precursor solution may be coated on the surface of the hole transport layer or the electron transport layer.

[0071] In step S2, the annealing temperature may be 100-180°C, such as 120-140°C, and the annealing time may be 5-60 min, such as 10-30 min.

[0072] In some embodiments, the thickness of the perovskite film is 400-800 nm, such as 500-600 nm.

[0073] The present invention also provides a perovskite solar cell, which includes a conductive substrate layer, a hole transport layer, the perovskite film described herein, an electron transport layer, a blocking layer and an electrode.

[0074] The material of the transparent conductive electrode suitable for the conductive substrate layer of the present invention can be selected from ITO or FTO. In the present invention, the preparation of the conductive substrate layer is not particularly limited, and the conventional method for preparing the conductive substrate layer in the art can be used, for example, a magnetron sputtering process is used to deposit it on a substrate surface such as a transparent glass substrate. The process parameters can be adjusted according to the target thickness of the conductive substrate layer. In some embodiments, the thickness of the transparent conductive electrode deposited on the substrate surface is 80nm-120nm.

[0075] The material of the hole transport layer suitable for the present invention can be selected from one or both of nickel oxide and self-assembled monolayer. In some embodiments, the material of the self-assembled monolayer is selected from one or more of [2-(9H-carbazole-9-yl)ethyl]phosphonic acid, [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid and [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid. The preparation of the hole transport layer is not particularly limited, and the conventional method for preparing the hole transport layer in the art can be used, such as the process of magnetron sputtering. The process parameters can be adjusted according to the target thickness of the hole transport layer. In some embodiments, the thickness of the hole transport layer is 1-10nm, such as 1nm-5nm.

[0076] Materials suitable for the electron transport layer of the present invention include, but are not limited to, one or more of C60, TiO2, ZnO, WO3, SnO2, Zn2SnO4, fullerene and its derivatives. The preparation of the electron transport layer is not particularly limited, and the conventional method for preparing the electron transport layer in the art can be used, including but not limited to one or more of spin coating, spray coating, spray pyrolysis, slit coating, and atomic layer deposition. The process parameters can be adjusted according to the target thickness of the electron transport layer. In some embodiments, the thickness of the electron transport layer is 10nm-50nm, such as 20-40nm.

[0077] Materials suitable for the barrier layer of the present invention can be selected from titanium dioxide (TiO2) and / or BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline). The preparation of the hole transport layer is not particularly limited, and the conventional method for preparing the barrier layer in the art can be used, such as pulsed laser deposition (PLD) and / or sol-gel method (Sol-Gel). The process parameters can be adjusted according to the target thickness of the barrier layer. In some embodiments, the thickness of the barrier layer is 1-10nm, such as 5nm-8nm.

[0078] The material suitable for the electrode of the present invention can be selected from one or more of copper, aluminum and silver. In some embodiments, the thickness of the electrode is 90nm-400nm, such as 100-150nm.

[0079] In some embodiments, the perovskite solar cell is a single-junction perovskite solar cell or a tandem perovskite solar cell. Tandem perovskite solar cells exemplarily include two-terminal tandem cells, three-terminal tandem cells, and four-terminal tandem cells.

[0080] In some embodiments, the perovskite solar cell is an inverted perovskite solar cell or a formal perovskite solar cell.

[0081] The perovskite solar cell of the present invention can be prepared by conventional methods for preparing perovskite solar cells in the art. In some embodiments, the method for preparing the perovskite solar cell of the present invention is as follows: Figure 1As shown. A first electrode is formed on a substrate to obtain a conductive base layer (such as an ITO or FTO conductive layer + transparent conductive glass). A first transmission layer is formed on the first electrode. When preparing an inverse perovskite solar cell, the first transmission layer is a hole transmission layer; when preparing a formal perovskite solar cell, the first transmission layer is an electron transmission layer. The perovskite precursor solution of the present invention is used to form a perovskite absorption layer on the first transmission layer, which is the perovskite film of the present invention. A second transmission layer is formed on the perovskite absorption layer. When preparing an inverse perovskite solar cell, the second transmission layer is an electron transmission layer; when preparing a formal perovskite solar cell, the second transmission layer is a hole transmission layer. Finally, a second electrode is formed on the second transmission layer. The second electrode can be a back electrode metal electrode such as Cu / Ag / Au or a transparent electrode such as ITO / IZO / IWO.

[0082] 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.

[0083] Example 1

[0084] Step 1: Place the laser-scribed 10×10 cm FTO glass into a cleaning rack, and use a detergent: deionized water volume ratio of 1:20 solution, deionized water, and anhydrous ethanol to ultrasonically clean it in an ultrasonic machine for 20 minutes, and then blow dry it with nitrogen for later use.

[0085] Step 2: Preparation of hole transport layer

[0086] 12 mg of Me-4PACz ([4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphoric acid) was weighed, and 20 ml of anhydrous ethanol solvent was added in a glove box. After fully dissolving for 4 hours, a precursor solution for preparing a hole transport layer was obtained.

[0087] The FTO glass cleaned in step 1 was treated with UV ozone for 15 minutes, and a hole transport layer was prepared by a slit coating method using the prepared Me-4PACz solution. The hole transport layer was annealed at 100° C. for 10 minutes to obtain a hole transport layer of about 2 nm.

[0088] Step 3: Preparation of perovskite absorber layer (perovskite film)

[0089] Weigh 11064.2 mg of PbI2, 3714.6 mg of FAI and 623.5 mg of CsI, and add 333.7 mg of PbCl2. Then, add 16 ml of DMF and 4 ml of DMSO solvent in the glove box, and add p-hydroxybenzoic acid as an additional solvent to prepare 20 ml of precursor solution. 0.9 Cs 0.1 The molar concentration of PbI3 is 1.2M, and the molar concentration of the additive is FA 0.9 Cs 0.1 The molar concentration of PbI3 is 3%, i.e. 0.036M.

[0090] Use the FA prepared in step 3 0.9 Cs 0.1 The PbI3 precursor solution was coated on the surface of the obtained SAM layer (hole transport layer) by slit coating method. After coating, annealing was performed at 130°C for 20 minutes to obtain a 550nm FA 0.9 Cs 0.1 PbI3 perovskite thin film.

[0091] Step 4: Preparation of electron transport layer, BCP as blocking layer and back electrode

[0092] The FA obtained in step 3 0.9 Cs 0.1 The PbI3 perovskite film was placed in a sealed box, and C60 and BCP were deposited on it in sequence by thermal evaporation to obtain a 30nm electron transport layer C60 and a 6nm barrier layer BCP. Then, after laser scribbling the grooves, thermal evaporation equipment was used again to deposit a 110nm Cu electrode. Finally, laser scribbling and local edge cleaning were performed to obtain an effective area of ​​49cm 2 FA 0.9 Cs 0.1 PbI3 inverse perovskite solar cells.

[0093] Example 2

[0094] The only difference between Example 2 and Example 1 is that p-hydroxybenzoic acid is replaced by m-hydroxybenzoic acid.

[0095] Example 3

[0096] The only difference between Example 3 and Example 1 is that p-hydroxybenzoic acid is replaced by o-hydroxybenzoic acid.

[0097] Example 4

[0098] The only difference between Example 4 and Example 1 is that the molar concentration of p-hydroxybenzoic acid is FA 0.9 Cs 0.1 The molar concentration of PbI3 is 1%.

[0099] Example 5

[0100] The only difference between Example 5 and Example 1 is that the molar concentration of p-hydroxybenzoic acid is adjusted to FA 0.9 Cs 0.1 The molar concentration of PbI3 is 10%.

[0101] Comparative Example 1

[0102] The difference between Comparative Example 1 and Example 1 is that in step 3, when preparing FA 0.9 Cs 0.1 No additive p-hydroxybenzoic acid was added to the PbI3 precursor solution.

[0103] Test Example 1

[0104] The device performance of the perovskite solar cells prepared in Examples 1-5 and Comparative Example 1 was tested, and the test results are shown in Table 1. Photoelectric test conditions: test spectrum AM 1.5G, test light intensity 1000W / m 2 , the test temperature is around room temperature 25℃.

[0105] Open circuit voltage V OC is the terminal voltage of the battery in the open circuit state. SC It is the current density that a perovskite solar cell can generate under short-circuit conditions. The fill factor FF is the ratio of the maximum power of a solar cell to the product of the open circuit voltage and the short-circuit current. The photoelectric conversion efficiency PCE can be calculated by measuring the current density-voltage curve (J-V curves) of the solar cell.

[0106] The test results are shown in Table 1 below:

[0107] Table 1: Photovoltaic performance parameters of perovskite solar cells

[0108] category PCE(%) <![CDATA[V OC (V)]]> FF(%) <![CDATA[J SC (mA / cm 2 )]]> Example 1 18.52 10.84 78.36 2.18 Example 2 18.37 10.95 77.66 2.16 Example 3 18.15 10.87 76.95 2.17 Example 4 17.96 10.82 76.85 2.16 Example 5 17.92 10.76 76.75 2.17 Comparative Example 1 15.06 9.96 72.56 2.08

[0109] From the results of Examples 1-5 and Comparative Example 1, it can be seen that Examples 1-5 significantly improve the photovoltaic properties of the device, such as photoelectric conversion efficiency and fill factor, by adding the additive of the present invention.

[0110] Test Example 2

[0111] The crystal morphology of the perovskite films obtained in Example 1 and Comparative Example 1 was measured using a scanning electron microscope (SEM).

[0112] The crystal morphology of the perovskite film obtained in Example 1 is as follows: Figure 2 The experimental groups are shown in . Figure 2The crystal morphology of the perovskite film obtained by the comparative example 1 without adding the additives described in this article is as follows Figure 2 As shown in the control group. Figure 2 It can be seen that the grain size of the perovskite film in the experimental group of the present invention is larger and the grain boundaries are fewer than those in the control group.

[0113] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A perovskite precursor solution, characterized in that: The perovskite precursor solution contains a perovskite active material, an additive and a solvent; the perovskite active material is a perovskite active material that does not contain a methylamine group; and the additive is a compound of formula A: wherein R1 and R2 are each independently a hydroxyl group, an alkyl group substituted with a hydroxyl group, a carboxyl group, an alkyl group substituted with a carboxyl group, or an alkyl group substituted with a hydroxyl group and a carboxyl group.

2. The perovskite precursor solution according to claim 1, characterized in that: R1 and R2 are not the same; R1 and R2 are in the para, meta or ortho positions; A hydroxy-substituted alkyl group contains only one hydroxy group; The carboxyl-substituted alkyl group contains only one carboxyl group; The alkyl group substituted with hydroxyl and carboxyl contains only one hydroxyl group and one carboxyl group; The alkyl group is C 1-10 Straight chain alkyl or C 1-10 Branched chain alkyl.

3. The perovskite precursor solution according to claim 1, characterized in that The additive includes one or more of p-hydroxybenzoic acid, m-hydroxybenzoic acid and o-hydroxybenzoic acid.

4. The perovskite precursor solution according to claim 1, characterized in that: The perovskite active material is an ABX3 compound, where A is FA + and / or Cs + ; B is Pb 2+ and / or Sn 2+ ; X is 1 - Br - and Cl - One of many; The molar concentration of the perovskite active material in the perovskite precursor solution is 1-1.8 mol / L; The molar concentration of the additive in the perovskite precursor solution is 0.01-0.18 mol / L; The molar ratio of the additive to the perovskite active material in the perovskite precursor solution is (0.01-0.1):

1.

5. The perovskite precursor solution according to claim 1, characterized in that The solvent is selected from one or more of N,N-dimethylformamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, γ-butyrolactone, 1,3-dimethyl-2-imidazolidinone, dimethylacetamide, N,N-dimethylpropylene urea, acetonitrile or 2-mercaptoethanol.

6. A method for regulating the crystallization of methylamine-free perovskite or preparing a methylamine-free perovskite film, characterized in that: The method comprises the following steps: coating the perovskite precursor solution as described in any one of claims 1 to 5 on a substrate layer, and annealing to obtain the perovskite film.

7. The preparation method according to claim 6, characterized in that: The coating method is one or more of spin coating, slit coating, blade coating, screen printing and inkjet printing; The substrate layer is a hole transport layer or an electron transport layer; The annealing temperature is 100-180°C, and the annealing time is 5-60min; The thickness of the perovskite film is 400-800nm.

8. A perovskite film, characterized in that: The perovskite film contains a perovskite active material and an additive, wherein the perovskite active material is a perovskite active material that does not contain a methylamine group; and the additive is a compound of formula A as described in any one of claims 1 to 3.

9. The perovskite film according to claim 8, characterized in that The perovskite film is prepared by the method for preparing a perovskite film according to claim 6 or 7.

10. A perovskite solar cell, characterized in that: The perovskite solar cell comprises a conductive substrate layer, a hole transport layer, the perovskite film according to claim 8, an electron transport layer, a blocking layer and an electrode. 11.Select from the following applications: Use of an additive in controlling the crystallization rate and morphology of methylamine-free perovskite, wherein the additive is a compound of formula A as described in any one of claims 1 to 3; Use of an additive in preparing a perovskite film with increased grain size and reduced grain boundaries, wherein the additive is a compound of formula A as described in any one of claims 1 to 3; Use of the perovskite precursor solution according to claim 1 in preparing a perovskite film with increased grain size and reduced grain boundaries; Use of the perovskite precursor solution as claimed in claim 1 in the preparation of a perovskite solar cell with improved photoelectric conversion efficiency and stability.

Images