Perovskite solar cell and preparation method thereof

Abstract

The invention provides a perovskite solar cell and a preparation method thereof. The method comprises the following steps: S1, preparing a first carrier transport layer on one side of a conductive surface of a transparent conductive substrate; s2, a perovskite precursor solution is prepared, the precursor solution comprises a perovskite precursor and an additive, and the additive is at least one of a compound shown in the general formula (I) and hydrochloride of the compound; s3, coating the surface of one side, far away from the transparent conductive substrate, of the first carrier transport layer with the perovskite precursor solution, and performing annealing treatment to obtain a perovskite active layer; step S4 and step S5, sequentially preparing a second carrier transport layer and a metal electrode layer on the surface of one side, far away from the transparent conductive substrate, of the perovskite active layer to obtain the perovskite solar cell. When the perovskite active layer is prepared, the additive is introduced, so that surface and grain boundary defects of the perovskite active layer can be passivated, the stability of the perovskite active layer is improved, and the photoelectric conversion efficiency of the perovskite solar cell is improved. # imgabs0 #

Description

Technical Field

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

[0002] Perovskite solar cells have attracted widespread attention due to their high energy conversion efficiency and low cost. Their laboratory photoelectric conversion efficiency has reached more than 26.7%. The preparation of the perovskite active light-absorbing layer is the core of perovskite solar cells and the focus of perovskite solar cell research. In recent years, halide perovskite materials have attracted widespread attention at home and abroad due to their unique optical properties and relatively low preparation costs.

[0003] At present, the most commonly used process for preparing perovskite solar cells is to use a low-temperature solution method to prepare perovskite thin films. However, due to the low formation energy of perovskite materials, defects are easily formed inside, on the surface and at the grain boundaries of the perovskite thin films during the preparation process. These defects can not only capture charge carriers generated by light, causing non-radiative recombination and thus energy loss, but also aggravate the aging rate of perovskite solar cells, thereby limiting the further improvement of their photoelectric conversion efficiency and stability.

[0004] In summary, researching and developing a perovskite solar cell and a preparation method thereof are of great significance for improving the quality of perovskite films, reducing their defect state density, and improving the photoelectric conversion efficiency and stability of perovskite solar cells. Summary of the invention

[0005] The main purpose of the present invention is to provide a perovskite solar cell and a preparation method thereof, so as to solve the problem that the perovskite film prepared by the low-temperature solution method in the prior art has a high defect state and the resulting low photoelectric conversion efficiency of the perovskite solar cell.

[0006] In order to achieve the above-mentioned object, the present invention provides a method for preparing a perovskite solar cell, which comprises: step S1, preparing a first carrier transport layer on one side of the conductive surface of a transparent conductive substrate; step S2, preparing a perovskite precursor solution, wherein the perovskite precursor solution comprises a perovskite precursor and an additive, wherein the additive is at least one of the compounds represented by general formula (I) and their hydrochlorides: Wherein, R1 is selected from hydrogen, phenyl substituted by at least one halogen atom and / or amino group, or benzoyl substituted by at least one halogen atom; m is 0 or 1, wherein m is 0, R2 and R3 are each independently hydrogen; or, m is 1, R2 and R3 are each independently hydrogen, or R2 and R3 and the carbon substituted by the two are connected to form a benzene ring; Y is selected from N, S or O; n is 1 or 2, wherein n is 1, R4 is selected from hydrogen or thiol, or, n is 2, R4 is hydrogen; when m is 0, n is not 1; step S3, coating the perovskite precursor solution on the side surface of the first carrier transport layer away from the transparent conductive substrate, and obtaining the perovskite active layer after annealing; step S4, preparing the second carrier transport layer on the side surface of the perovskite active layer away from the transparent conductive substrate; step S5, preparing the metal electrode layer on the side surface of the second carrier transport layer away from the transparent conductive substrate to obtain a perovskite solar cell.

[0007] Further, R1 is selected from a phenyl group substituted by a halogen atom, a phenyl group substituted by a halogen atom and an amino group, or a benzoyl group substituted by a halogen atom; preferably, the halogen atom is Cl, Br or I, and R2, R3 and R4 are all hydrogen; preferably, R1 is hydrogen, m is 1, R2 and R3 and the carbon substituted by the two are connected to form a benzene ring, n is 1 and R4 is a thiol group; preferably, R1 is and m is 1; preferably, Y is N or S; preferably, m is 1 and n is 2.

[0008] Further, the additive is selected from one or more of the following compounds: 1-(4-iodophenyl)piperazine hydrochloride, 1-(4-chlorophenyl)piperazine hydrochloride, 1-(4-bromophenyl)piperazine hydrochloride, 2-mercaptobenzothiazole, 5-chloro-2-morpholin-4-yl-phenylamine, 3-fluoro-4-thiomorpholinoaniline, and 4-(3-bromobenzoyl)morpholine.

[0009] Furthermore, the preparation method of the perovskite precursor solution includes: mixing a perovskite precursor, an additive and a solvent to obtain a perovskite precursor solution; preferably, the molar ratio of the additive to the perovskite precursor is (0.01-0.1):1; preferably, in the perovskite precursor solution, the molar concentration of the perovskite precursor is 0.5-2 mol / L; preferably, the solvent is selected from one or more of the group consisting of N,N-dimethylformamide, dimethyl sulfoxide and propylene carbonate.

[0010] Further, the material of the perovskite precursor is ABX3, wherein A is selected from organic cations and / or inorganic cations, B is selected from divalent metal cations, and X is selected from halogen atoms; preferably, A is selected from CH3NH3 + NH=CHNH3 + and Cs +One or more of the group consisting of; B is selected from Pb 2+ and / or Sn 2+ ; X is selected from Cl - Br - and I - One or more of the groups.

[0011] Furthermore, the thickness of the perovskite active layer is 200-800 nm.

[0012] Further, step S3 comprises: coating by spin coating, blade coating or slit coating; preferably, the temperature of annealing treatment is 100-300° C., and the time is 5-60 min.

[0013] Further, step S1 includes: preparing a first carrier transport layer by magnetron sputtering, atomic layer deposition, spin coating, doctor blading or chemical bath deposition; preferably, step S4 includes: preparing a second carrier transport layer by spin coating, atomic layer deposition or vacuum evaporation; preferably, step S5 includes: preparing a metal electrode layer by vacuum evaporation.

[0014] Further, the first carrier transport layer is a hole transport layer, and the second carrier transport layer is an electron transport layer; preferably, the material of the first carrier transport layer is selected from one or more of the group consisting of nickel oxide, [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid, [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid and [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid; preferably, the material of the second carrier transport layer is selected from titanium oxide, tin oxide, [6,6]-phenyl-C 61 -Methyl butyrate and C 60 One or more of the groups.

[0015] Furthermore, the material of the metal electrode layer is selected from one or more of the group consisting of gold, silver and copper.

[0016] Furthermore, the transparent conductive substrate is selected from ITO conductive glass, FTO conductive glass or AZO conductive glass.

[0017] In order to achieve the above object, another aspect of the present invention further provides a perovskite solar cell, which is prepared by the preparation method of the perovskite solar cell provided in the present application. The perovskite solar cell comprises a transparent conductive substrate, a first carrier transport layer, a perovskite active layer, a second carrier transport layer and a metal electrode layer stacked in sequence.

[0018] By applying the technical solution of the present invention, the present application provides a method for preparing a perovskite solar cell, wherein an additive having a compound structure shown in the general formula (I) is introduced into the preparation of the perovskite precursor solution in step S2, and the perovskite precursor solution containing the additive is coated on the surface of the first carrier transport layer away from the transparent conductive substrate in step S3, and the perovskite active layer is obtained after annealing. The phenyl or benzoyl group in R1 of the compound shown in the general formula (I), and the benzene ring formed by connecting R2 and R3 and the carbon substituted by the two are used as rigid groups, which can inhibit the distortion of the perovskite precursor structure, thereby improving the structural stability of the perovskite precursor, and inhibiting its decomposition and aging. Halogen atoms have strong electronegativity, and amino and thiol groups have strong nucleophilicity, which can combine with the dangling bonds on the surface of the perovskite to form stable chemical bonds, thereby reducing the surface energy of the perovskite, reducing its surface defects, and inhibiting non-radiative recombination. The presence of the heterocyclic structure containing heteroatoms in the compound represented by the general formula (I) can improve the crystal structure of the perovskite precursor, promote the formation of a more ordered and stable perovskite phase, thereby improving the uniformity and density of the perovskite active layer, and reducing grain boundary defects and vacancy defects. The additive having the above structure is introduced into the perovskite precursor solution to prepare the perovskite active layer, which can passivate the surface defects and grain boundary defects of the perovskite active layer, improve its stability, and thus improve the photoelectric conversion efficiency of the perovskite solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0020] Figure 1 A schematic diagram of the stacked structure of a perovskite solar cell in one embodiment of the present application is shown.

[0021] The above drawings include the following reference numerals:

[0022] 10. Transparent conductive substrate; 20. First carrier transport layer; 30. Perovskite active layer; 40. Second carrier transport layer; 50. Metal electrode layer. DETAILED DESCRIPTION

[0023] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0024] As described in the background art, the existing perovskite film prepared by the low temperature solution method has a high defect state, resulting in the problem of low photoelectric conversion efficiency of the prepared perovskite solar cell. In order to solve the above technical problems, the first aspect of the present application provides a method for preparing a perovskite solar cell, such as Figure 1 As shown, the preparation method comprises: step S1, preparing a first carrier transport layer 20 on one side of the conductive surface of the transparent conductive substrate 10; step S2, preparing a perovskite precursor solution, the perovskite precursor solution comprising a perovskite precursor and an additive, the additive being at least one of the compound represented by general formula (I) and its hydrochloride: wherein R1 is selected from hydrogen, phenyl substituted by at least one halogen atom and / or amino group, or benzoyl substituted by at least one halogen atom; m is 0 or 1, wherein m is 0, R2 and R3 are each independently hydrogen; or, m is 1, R2 and R3 are each independently hydrogen, or R2 and R3 and the carbon substituted by the two are connected to form a benzene ring; Y is selected from N, S or O; n is 1 or 2, wherein n is 1, R4 is selected from hydrogen or mercapto, or, n is 2, R4 is hydrogen; when m is 0 n is not 1; step S3, coating the perovskite precursor solution on the surface of the first carrier transport layer 20 away from the transparent conductive substrate 10, and obtaining the perovskite active layer 30 after annealing; step S4, preparing the second carrier transport layer 40 on the surface of the perovskite active layer 30 away from the transparent conductive substrate 10; step S5, preparing the metal electrode layer 50 on the surface of the second carrier transport layer 40 away from the transparent conductive substrate 10, to obtain a perovskite solar cell.

[0025] The present application provides a method for preparing a perovskite solar cell, wherein an additive having a compound structure shown in the general formula (I) is introduced into the preparation of a perovskite precursor solution in step S2, and the perovskite precursor solution containing the additive is coated on the surface of the first carrier transport layer 20 away from the transparent conductive substrate 10 in step S3, and a perovskite active layer 30 is obtained after annealing. The phenyl or benzoyl group in R1 of the compound shown in the general formula (I), and the benzene ring formed by connecting R2 and R3 and the carbon substituted by the two are used as rigid groups, which can inhibit the distortion of the perovskite precursor structure, thereby improving the structural stability of the perovskite precursor, and inhibiting its decomposition and aging. Halogen atoms have strong electronegativity, and amino and thiol groups have strong nucleophilicity, which can combine with the dangling bonds on the surface of the perovskite to form stable chemical bonds, thereby reducing the surface energy of the perovskite, reducing its surface defects, and inhibiting non-radiative recombination. The presence of the heterocyclic structure containing heteroatoms in the compound represented by the general formula (I) can improve the crystal structure of the perovskite precursor material, promote the formation of a more ordered and stable perovskite phase, thereby improving the uniformity and density of the perovskite active layer 30, and reducing grain boundary defects and vacancy defects. Introducing the additive having the above structure into the perovskite precursor solution to prepare the perovskite active layer 30 can passivate the surface defects and grain boundary defects of the perovskite active layer 30, improve its stability, and thus improve the photoelectric conversion efficiency of the perovskite solar cell.

[0026] In a preferred embodiment, R1 is a phenyl group substituted by a halogen atom, or a phenyl group substituted by a halogen atom and an amino group, or a benzoyl group substituted by a halogen atom; preferably, the halogen atom is Cl, Br or I, and R2, R3 and R4 are all hydrogen. Compared with other structures, the additive of the above structure is conducive to further exerting the role of halogen atoms, amino groups and rigid groups (such as phenyl groups, benzoyl groups), thereby passivating the surface defects and grain boundary defects of the perovskite active layer 30, inhibiting non-radiative recombination, and improving the stability of the perovskite active layer 30, thereby improving the photoelectric conversion efficiency of the perovskite solar cell.

[0027] In order to further passivate the surface defects and grain boundary defects of the perovskite active layer 30, further inhibit non-radiative recombination, and improve the stability of the perovskite active layer 30, thereby further improving the photoelectric conversion efficiency of the perovskite solar cell, preferably, R1 is And m is 1.

[0028] In a preferred embodiment, R1 is hydrogen, m is 1, R2 and R3 and the carbon substituted by the two are connected to form a benzene ring, n is 1 and R4 is a mercapto group. Compared with other structures, the additive of the above structure is conducive to further exerting the strong nucleophilicity of the mercapto group, and is conducive to further exerting the role of the rigid group of the benzene ring formed by R2 and R3 and the carbon substituted by the two, so as to passivate the surface defects and grain boundary defects of the perovskite active layer 30, inhibit non-radiative recombination, improve the stability of the perovskite active layer 30, and further improve the photoelectric conversion efficiency of the perovskite solar cell.

[0029] In order to further improve the crystal structure of the perovskite precursor and promote the formation of a more ordered and stable perovskite phase, thereby further improving the uniformity and density of the perovskite active layer 30, further reducing the perovskite grain boundaries and vacancy defects, and thus further improving the photoelectric conversion efficiency of the perovskite solar cell, preferably, Y is N or S, and more preferably, m is 1 and n is 2.

[0030] In order to improve the chemical stability and dispersibility of the additive, thereby further improving the surface defects and grain boundary defects of the perovskite active layer 30, in a preferred embodiment, the additive is a hydrochloride of the compound represented by general formula (I).

[0031] In a preferred embodiment, the additive includes but is not limited to one or more of the following compounds: 1-(4-iodophenyl)piperazine hydrochloride, 1-(4-chlorophenyl)piperazine hydrochloride, 1-(4-bromophenyl)piperazine hydrochloride, 2-mercaptobenzothiazole, 5-chloro-2-morpholin-4-yl-phenylamine, 3-fluoro-4-thiomorpholinoaniline, and 4-(3-bromobenzoyl)morpholine.

[0032] Compared with other structures, the additives of the above structure are beneficial to passivating the surface defects and grain boundary defects of the perovskite active layer 30, suppressing non-radiative recombination, and improving the stability of the perovskite active layer 30, thereby improving the photoelectric conversion efficiency of the perovskite solar cell.

[0033] In order to improve the dispersibility of the additive and the perovskite precursor, thereby facilitating obtaining the perovskite precursor solution, in a preferred embodiment, the method for preparing the perovskite precursor solution includes: mixing the perovskite precursor, the additive and a solvent to obtain the perovskite precursor solution.

[0034] In a preferred embodiment, the molar ratio of the additive to the perovskite precursor is (0.01-0.1): 1. The molar ratio of the additive to the perovskite precursor includes but is not limited to the above range, and limiting it within the above range is conducive to introducing a more suitable amount of the additive and making it work, thereby being conducive to passivating the surface defects and grain boundary defects of the perovskite active layer 30, being conducive to inhibiting non-radiative recombination, and being conducive to improving the stability and density of the perovskite active layer 30, thereby being conducive to improving the photoelectric conversion efficiency of the perovskite solar cell.

[0035] In a preferred embodiment, the molar concentration of the perovskite precursor in the perovskite precursor solution is 0.5 to 2 mol / L. The mass concentration of the perovskite precursor includes but is not limited to the above range, and limiting it within the above range is conducive to improving the uniformity and density of the perovskite active layer 30, improving the stability of the perovskite active layer 30, and reducing its surface defects and grain boundary defects, thereby facilitating improving the photoelectric conversion efficiency of the perovskite solar cell.

[0036] In order to improve the dispersibility of the additive and the perovskite precursor, thereby obtaining a more uniform perovskite precursor solution, in a preferred embodiment, the solvent includes but is not limited to one or more of the group consisting of N,N-dimethylformamide, dimethyl sulfoxide and propylene carbonate.

[0037] In order to improve the light absorption efficiency of perovskite materials and thus improve the photoelectric conversion efficiency of perovskite solar cells, in a preferred embodiment, the material of the perovskite precursor is ABX3, wherein A includes but is not limited to organic cations and / or inorganic cations, B includes but is not limited to divalent metal cations, and X includes but is not limited to halogen atoms.

[0038] In order to further improve the light absorption efficiency of the perovskite material, thereby further improving the photoelectric conversion efficiency of the perovskite solar cell, preferably, A includes but is not limited to CH3NH3 + NH=CHNH3 + and Cs + One or more of the group consisting of; B includes but is not limited to Pb 2+ and / or Sn 2+ ; X includes but is not limited to Cl - Br - and I - One or more of the groups.

[0039] In a preferred embodiment, the thickness of the perovskite active layer 30 is 200-800 nm. The thickness of the perovskite active layer 30 includes but is not limited to the above range, which is beneficial to improving the stability, durability and photoelectric conversion efficiency of the perovskite solar cell.

[0040] In a preferred embodiment, step S3 includes: coating by spin coating, blade coating or slit coating. Compared with other methods, the above method is conducive to improving the film forming property and uniformity of the perovskite active layer 30, and is conducive to obtaining a higher quality film layer.

[0041] In order to improve the crystallinity of the perovskite active layer 30, reduce its surface defects, and enhance its thermal stability and chemical stability, in a preferred embodiment, the annealing treatment is performed at a temperature of 100 to 300° C. for 5 to 60 minutes.

[0042] In a preferred embodiment, step S1 includes: preparing the first carrier transport layer 20 by magnetron sputtering, atomic layer deposition, spin coating, blade coating or chemical bath deposition; step S4 includes: preparing the second carrier transport layer 40 by spin coating, atomic layer deposition or vacuum evaporation; step S5 includes: preparing the metal electrode layer 50 by vacuum evaporation. Compared with other methods, the above method is conducive to improving the film forming properties and uniformity of the first carrier transport layer 20, the second carrier transport layer 40 and the metal electrode layer 50, thereby facilitating the acquisition of a higher quality film layer.

[0043] The perovskite solar cell provided in the present application may be a perovskite solar cell with an inverted structure (pin). In a preferred embodiment, the first carrier transport layer 20 is a hole transport layer, and the second carrier transport layer 40 is an electron transport layer.

[0044] In a preferred embodiment, the thickness of the first carrier transport layer 20 and the second carrier transport layer 40 are independently 10 to 40 nm. The thickness of the first carrier transport layer 20 and the second carrier transport layer 40 includes but is not limited to the above range, and limiting it within the above range is conducive to improving the carrier collection efficiency of the first carrier transport layer 20 and the second carrier transport layer 40, and is conducive to reducing the recombination of carriers, thereby facilitating the improvement of the carrier transport efficiency, and further facilitating the improvement of the photoelectric conversion efficiency of the perovskite solar cell.

[0045] In a preferred embodiment, the material of the first carrier transport layer 20 includes, but is not limited to, one or more of the group consisting of nickel oxide, [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz), [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid (MeO-4PACz) and [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACz). Compared with other types, the use of the above-mentioned first carrier transport material is conducive to improving the carrier transport efficiency of the first carrier transport layer 20 and the energy level matching and interface stability between it and the perovskite active layer 30, thereby helping to improve the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0046] In a preferred embodiment, the material of the second carrier transport layer 40 includes but is not limited to titanium oxide, tin oxide, [6,6]-phenyl-C 61 -Methyl butyrate (PC 61 BM) and C 60 Compared with other types, the use of the second carrier transport material of the above type is conducive to improving the carrier transport efficiency of the second carrier transport layer 40 and the energy level matching and interface stability between the second carrier transport layer 40 and the perovskite active layer 30, thereby improving the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0047] In a preferred embodiment, the material of the metal electrode layer 50 includes, but is not limited to, one or more of the group consisting of gold, silver and copper. Compared with other types, the use of the above-mentioned types of metal electrode materials is conducive to improving the conductivity of the metal electrode layer 50, thereby facilitating the improvement of the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0048] In order to further improve the conductivity and stability of the metal electrode layer 50, preferably, the thickness of the metal electrode layer 50 is 50-150 nm.

[0049] The present application has no particular limitation on the type of the transparent conductive substrate 10, as long as it is conductive and has high light transmittance. In a preferred embodiment, the transparent conductive substrate 10 includes but is not limited to ITO conductive glass, FTO conductive glass or AZO conductive glass.

[0050] The second aspect of the present application also provides a perovskite solar cell, such as Figure 1 As shown, the perovskite solar cell is prepared by the preparation method of the above-mentioned perovskite solar cell provided in the present application; it includes a transparent conductive substrate 10, a first carrier transport layer 20, a perovskite active layer 30, a second carrier transport layer 40 and a metal electrode layer 50 which are stacked in sequence.

[0051] The method for preparing the perovskite solar cell described above can be used to obtain a perovskite solar cell with higher photoelectric conversion efficiency. The prepared perovskite solar cell has the following characteristics: Figure 1 The stacked structure shown. When preparing the perovskite active layer 30, an additive of the compound structure shown in the general formula (I) of the present application is introduced, wherein the phenyl or benzoyl group in R1, and the benzene ring formed by connecting the carbon substituted by R2 and R3 and the two as rigid groups can inhibit the distortion of the perovskite precursor structure, thereby improving the structural stability of the perovskite precursor and inhibiting its decomposition and aging. Halogen atoms have strong electronegativity, and amino and thiol groups have strong nucleophilicity, which can combine with the dangling bonds on the surface of the perovskite to form stable chemical bonds, thereby reducing the surface energy of the perovskite, reducing its surface defects, and inhibiting non-radiative recombination. The presence of a heterocyclic structure containing heteroatoms in the compound shown in the general formula (I) can improve the crystal structure of the perovskite precursor material, promote it to form a more ordered and more stable perovskite phase, thereby improving the uniformity and density of the perovskite active layer 30, and reducing grain boundary defects and vacancy defects. Introducing the additive having the above structure into the perovskite precursor solution to prepare the perovskite active layer 30 can passivate the surface defects and grain boundary defects of the perovskite active layer 30 and improve its stability, thereby improving the photoelectric conversion efficiency of the perovskite solar cell.

[0052] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0053] Example 1

[0054] A method for preparing a perovskite solar cell comprises the following steps:

[0055] (1) Providing a transparent conductive substrate 10: ultrasonically cleaning an ITO conductive glass with detergent, water and ethanol for 15 minutes, drying it for later use, and then treating the cleaned ITO conductive glass with ozone for 15 minutes for later use;

[0056] (2) Preparation of a hole transport layer: Spin coating 0.1 mL of a 15 mg / mL NiOx isopropanol solution at a speed of 3000 rpm on the conductive surface of the ITO conductive glass provided in step (1) for 30 seconds, and then annealing the glass on a hot plate at 120° C. for 20 minutes to obtain a NiOx layer with a thickness of 20 nm;

[0057] (3) Preparation of perovskite precursor solution: 232.8 mg FAI (iodine formamide), 7.98 mg MABr (methylammonium bromide), 19.49 mg CsI (cesium iodide), 27.53 mg PbBr2 (lead bromide), 676.6 mg PbI2 (lead iodide), 30.38 mg MACl (methylammonium chloride) and 4.86 mg additive 1-(4-iodophenyl)piperazine hydrochloride (CAS No.: 624726-35-8) were weighed and mixed with 0.8 mL N,N-dimethylformamide and 0.2 mL dimethyl sulfoxide, and stirred at 25 ° C and 800 rpm for 2 h to obtain a perovskite precursor solution; wherein the perovskite precursor (FAI) 0.95 MA 0.05 ) 0.95 Cs 0.05 Pb(I 0.95 Br 0.05 )3 has a molar concentration of 1.5 mol / L, and a molar ratio of the additive to the perovskite precursor is 0.01:1;

[0058] (4) Preparing a perovskite active layer 30: Spin coating the perovskite precursor solution prepared in step (3) on the surface of the NiOx layer prepared in step (2) on the side away from the ITO conductive glass, first spin coating at a rotation speed of 2000 rpm for 10 seconds, then spin coating at a rotation speed of 5000 rpm for 40 seconds, and quickly adding 200 μL of chlorobenzene 15 seconds before the end of spin coating for anti-solvent treatment, and then placing it on a hot plate at 100° C. for annealing for 30 minutes to obtain a perovskite active layer 30 with a thickness of 400 nm;

[0059] (5) Preparation of electron transport layer: The perovskite active layer 30 prepared in step (4) is placed on a surface away from the ITO conductive glass. The deposition rate was 30 nm. 60 layer;

[0060] (6) Preparation of metal electrode layer 50: The C prepared in step (5) 60 The layer is away from the surface of the ITO conductive glass. A Cu electrode layer with a thickness of 100 nm was obtained by evaporation at a deposition rate of .

[0061] Example 2

[0062] The difference from Example 1 is that in step (3), an equimolar amount of 1-(4-chlorophenyl)piperazine hydrochloride (CAS No.: 13078-12-1) is used to replace the additive 1-(4-iodophenyl)piperazine hydrochloride, and the remaining steps are the same as Example 1.

[0063] Example 3

[0064] The difference from Example 1 is that in step (3), an equimolar amount of 1-(4-bromophenyl)piperazine hydrochloride (CAS No.: 68104-62-1) is used to replace the additive 1-(4-iodophenyl)piperazine hydrochloride, and the remaining steps are the same as Example 1.

[0065] Example 4

[0066] The difference from Example 1 is that in step (3), an equimolar amount of 2-mercaptobenzothiazole (CAS No.: 149-30-4) is used to replace the additive 1-(4-iodophenyl)piperazine hydrochloride, and the remaining steps are the same as Example 1.

[0067] Example 5

[0068] The difference from Example 1 is that in step (3), an equimolar amount of 5-chloro-2-morpholin-4-yl-phenylamine (CAS No.: 90875-44-8) is used to replace the additive 1-(4-iodophenyl)piperazine hydrochloride, and the remaining steps are the same as Example 1.

[0069] Example 6

[0070] The difference from Example 1 is that in step (3), an equimolar amount of 4-(3-bromobenzoyl)morpholine (CAS No.: 153435-81-5) is used to replace the additive 1-(4-iodophenyl)piperazine hydrochloride, and the remaining steps are the same as Example 1.

[0071] Example 7

[0072] The difference from Example 1 is that in step (3), the molar ratio of the additive to the perovskite precursor is 0.1:1, and the remaining steps are the same as Example 1.

[0073] Example 8

[0074] The difference from Example 1 is that in step (3), the molar ratio of the additive to the perovskite precursor is 0.12:1, and the remaining steps are the same as Example 1.

[0075] Comparative Example 1

[0076] The difference from Example 1 is that in step (3), no additive is introduced when preparing the perovskite precursor solution, and the remaining steps are the same as Example 1.

[0077] Comparative Example 2

[0078] The difference from Example 1 is that in step (3), an equimolar amount of piperazine dihydrochloride hydrate (CAS No.: 207605-49-0) is used to replace the additive 1-(4-iodophenyl)piperazine hydrochloride, and the remaining steps are the same as in Example 1.

[0079] The photovoltaic performance of the perovskite solar cells prepared in all the above embodiments and comparative examples of the present application was tested. The effective area of ​​the device was 0.09 mm 2 , at 100mW / cm 2 The JV curve of the perovskite solar cell was tested using a solar simulator (Guangyan Technology, SS-X) and a Keithley 2400 source meter under simulated sunlight conditions. The test results are shown in Table 1 below.

[0080] Table 1

[0081]

[0082] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0083] By comparing Example 1 and Comparative Example 1, it can be seen that introducing an additive having a compound structure represented by the general formula (I) of the present application when preparing the perovskite active layer 30 is beneficial to passivating the surface defects and grain boundary defects of the perovskite active layer 30, is beneficial to inhibiting non-radiative recombination, is beneficial to improving the stability of the perovskite active layer 30, and further is beneficial to improving the photoelectric conversion efficiency of the perovskite solar cell.

[0084] By comparing Examples 1 to 6 and Comparative Example 2, it can be seen that, compared with other structures, introducing an additive having the above-mentioned structure of the present application into a perovskite precursor solution to prepare a perovskite active layer 30 can passivate surface defects and grain boundary defects of the perovskite active layer 30, improve its stability, and thus improve the photoelectric conversion efficiency of the perovskite solar cell.

[0085] By comparing Examples 1, 7 and 8, it can be seen that, compared with other ranges, limiting the molar ratio of the additive to the perovskite precursor within the above range is conducive to introducing a more suitable amount of the additive and making it work, which is beneficial to passivating the surface defects and grain boundary defects of the perovskite active layer 30, suppressing non-radiative recombination, and improving the stability and density of the perovskite active layer 30, thereby helping to improve the photoelectric conversion efficiency of the perovskite solar cell.

[0086] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those described herein, for example.

[0087] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a perovskite solar cell, characterized in that: The preparation method comprises: Step S1, preparing a first carrier transport layer (20) on one side of the conductive surface of the transparent conductive substrate (10); Step S2, preparing a perovskite precursor solution, wherein the perovskite precursor solution comprises a perovskite precursor and an additive, wherein the additive is at least one of the compounds represented by the general formula (I) and their hydrochlorides: wherein R1 is selected from hydrogen, phenyl substituted by at least one halogen atom and / or amino group, or benzoyl substituted by at least one halogen atom; m is 0 or 1, wherein m is 0, R2 and R3 are each independently hydrogen; or, m is 1, R2 and R3 are each independently hydrogen, or R2 and R3 and the carbon substituted by the two are connected to form a benzene ring; Y is selected from N, S or O; n is 1 or 2, wherein n is 1 and R4 is selected from hydrogen or mercapto, or n is 2 and R4 is hydrogen; when m is 0, n is not 1; Step S3, coating the perovskite precursor solution on a surface of the first carrier transport layer (20) that is away from the transparent conductive substrate (10), and obtaining a perovskite active layer (30) after annealing; Step S4, preparing a second carrier transport layer (40) on a surface of the perovskite active layer (30) that is away from the transparent conductive substrate (10); Step S5, preparing a metal electrode layer (50) on the surface of the second carrier transport layer (40) on the side away from the transparent conductive substrate (10) to obtain the perovskite solar cell.

2. The method for preparing a perovskite solar cell according to claim 1, characterized in that: The R1 is selected from a phenyl group substituted by a halogen atom, a phenyl group substituted by a halogen atom and an amino group, or a benzoyl group substituted by a halogen atom; preferably, the halogen atom is Cl, Br or I, and the R2, the R3 and the R4 are all hydrogen; Preferably, R1 is hydrogen, m is 1, R2 and R3 and the carbon substituted by the two are connected to form a benzene ring, n is 1 and R4 is a mercapto group; Preferably, said R1 is And the m is 1; Preferably, Y is N or S; Preferably, m is 1 and n is 2.

3. The method for preparing a perovskite solar cell according to claim 1 or 2, characterized in that: The additive is selected from one or more of the following compounds: 1-(4-iodophenyl)piperazine hydrochloride, 1-(4-chlorophenyl)piperazine hydrochloride, 1-(4-bromophenyl)piperazine hydrochloride, 2-mercaptobenzothiazole, 5-chloro-2-morpholin-4-yl-phenylamine, 3-fluoro-4-thiomorpholinoaniline, and 4-(3-bromobenzoyl)morpholine.

4. The method for preparing a perovskite solar cell according to any one of claims 1 to 3, characterized in that: The method for preparing the perovskite precursor solution comprises: mixing the perovskite precursor, the additive and a solvent to obtain the perovskite precursor solution; Preferably, the molar ratio of the additive to the perovskite precursor is (0.01-0.1):1; Preferably, in the perovskite precursor solution, the molar concentration of the perovskite precursor is 0.5 to 2 mol / L.

5. The method for preparing a perovskite solar cell according to claim 4, characterized in that: The material of the perovskite precursor is ABX3, wherein A is selected from organic cations and / or inorganic cations, B is selected from divalent metal cations, and X is selected from halogen atoms; Preferably, A is selected from CH3NH3 + NH=CHNH3 + and Cs + One or more of the group consisting of; wherein B is selected from Pb 2+ and / or Sn 2+ ; X is selected from Cl - Br - and I - One or more of the groups consisting of; Preferably, the solvent is selected from one or more of the group consisting of N,N-dimethylformamide, dimethyl sulfoxide and propylene carbonate.

6. The method for preparing a perovskite solar cell according to claim 5, characterized in that: The thickness of the perovskite active layer (30) is 200-800 nm.

7. The method for preparing a perovskite solar cell according to claim 5 or 6, characterized in that: The step S3 comprises: performing the coating by spin coating, blade coating or slit coating; Preferably, the annealing treatment is performed at a temperature of 100 to 300° C. and for a time of 5 to 60 minutes.

8. The method for preparing a perovskite solar cell according to claim 1, characterized in that: The step S1 comprises: preparing the first carrier transport layer (20) by magnetron sputtering, atomic layer deposition, spin coating, scraping or chemical bath deposition; Preferably, the step S4 comprises: preparing the second carrier transport layer (40) by spin coating, atomic layer deposition or vacuum evaporation; Preferably, the step S5 comprises: preparing the metal electrode layer (50) by vacuum evaporation method.

9. The method for preparing a perovskite solar cell according to claim 1, characterized in that: The first carrier transport layer (20) is a hole transport layer, and the second carrier transport layer (40) is an electron transport layer; Preferably, the material of the first carrier transport layer (20) is selected from one or more of the group consisting of nickel oxide, [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid, [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid and [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid; Preferably, the material of the second carrier transport layer (40) is selected from titanium oxide, tin oxide, [6,6]-phenyl-C 61 -Methyl butyrate and C 60 One or more of the groups consisting of; Preferably, the material of the metal electrode layer (50) is selected from one or more of the group consisting of gold, silver and copper; Preferably, the transparent conductive substrate (10) is selected from ITO conductive glass, FTO conductive glass or AZO conductive glass.

10. A perovskite solar cell, characterized in that: The perovskite solar cell is prepared by the preparation method of the perovskite solar cell described in any one of claims 1 to 9 of the present application; the perovskite solar cell comprises a transparent conductive substrate (10), a first carrier transport layer (20), a perovskite active layer (30), a second carrier transport layer (40) and a metal electrode layer (50) which are stacked in sequence.

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