Perovskite solar cell and interface modification method thereof

Abstract

The invention discloses a perovskite solar cell and an interface modification method thereof. The perovskite solar cell comprises a charge transport layer and a perovskite layer, an interface modification layer is arranged between the charge transport layer and the perovskite layer; the interface modification layer comprises a polyfunctional group photoresponse molecule, the structural formula of the polyfunctional group photoresponse molecule is A-L-T, A is an anchoring group and comprises at least one of-SO3H,-COOH,-PO3H,-SH,-SiOR and-SO2Cl; l is a light response group and comprises at least one of-N = N-and-Ph-N = N-Ph-; and T is a terminal group and comprises at least one of-NH2,-OH,-I,-Cl,-Br,-F,-COOH,-N (CH3) 2 and-CN. Therefore, the perovskite solar cell provided by the invention has excellent photoelectric conversion efficiency and perovskite film crystallization quality.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic solar cells, and in particular, to a perovskite solar cell and an interface modification method thereof. Background Art

[0002] Guided by the "dual carbon" policy, solar energy has become one of my country's priority energy sources. This has led to the emergence of new third-generation thin-film solar cells, primarily including organic solar cells, dye-sensitized solar cells, quantum dot solar cells, and perovskite solar cells. Among these third-generation solar cells, perovskite solar cells are the latest to emerge but have seen the most rapid development. Over the past decade or so, their photoelectric conversion efficiency has rapidly increased from 3.8% to 27%. This is due to the excellent photoelectric properties of perovskite materials, including a suitably tunable bandgap, long carrier lifetime, high absorption coefficient, and high carrier mobility.

[0003] In the commercialization process of solar cells, cost, conversion efficiency and stability (lifespan) are three key indicators for examining their technical feasibility. Compared with crystalline silicon cells, perovskite solar cells have lower expected costs, and their laboratory efficiency is already close to that of crystalline silicon cells. However, their long-term stability issues have seriously restricted their further development. How to prepare efficient and stable perovskite solar cells remains the most urgent research task. The most important factor restricting the efficiency and stability of perovskite solar cells is the material problem, primarily the problems existing in the perovskite material itself, such as defects, phase stability and ion migration. Therefore, it is crucial to improve the quality of perovskite films and the quality of the transport layer / perovskite interface.

[0004] Advances in characterization techniques have revealed significant challenges at the interface beneath perovskite films (buried interfaces), with the residual presence of the high-boiling-point solvent dimethyl sulfoxide (DMSO) at the interface being a particularly serious problem. DMSO accumulation not only induces pore formation at the buried interface but also leads to crystal disorder and the accumulation of residual tensile stress in the bottom region of the perovskite layer, severely degrading power conversion efficiency and long-term operational stability. Therefore, mitigating buried interface defects through interface engineering, and thereby improving the crystallization quality of perovskite films, is of great significance in enhancing the efficiency and stability of perovskite solar cells. Summary of the Invention

[0005] The present invention aims to address at least one of the technical problems existing in the prior art to a certain extent. To this end, the present invention provides a method for preparing a perovskite solar cell and modifying its interface. The perovskite solar cell of the present invention has enhanced perovskite film and interface quality, and excellent photoelectric conversion efficiency and stability.

[0006] Therefore, in a first aspect of the present invention, the present invention provides a perovskite solar cell comprising: a charge transport layer, a perovskite layer;

[0007] An interface modification layer is provided between the charge transport layer and the perovskite layer;

[0008] The interface modification layer includes a multifunctional photoresponsive molecule, the structural formula of which is: ALT

[0009] Wherein, A is an anchoring group including at least one of -SO3H, -COOH, -PO3H, -SH, -SiOR, and -SO2Cl; L is a photoresponsive group including at least one of -N=N- and -Ph-N=N-Ph-; T is an end group including at least one of -NH2, -OH, -I, -Cl, -Br, -F, -COOH, -N(CH3)2, and -CN.

[0010] In this invention, the multifunctional photoresponsive molecules in the interface modification layer can directionally and double-sidedly passivate the interface defects between the charge transfer layer and the perovskite layer. Under the action of light, they undergo cis-trans isomerization, eliminating residual DMSO at the interface and the holes in the perovskite layer. At the same time, they regulate the crystallization process of the perovskite layer, thereby forming a high-performance perovskite solar cell. As a result, the photoelectric conversion efficiency and stability of the perovskite solar cell are further improved.

[0011] In some embodiments, the multifunctional photoresponsive molecule includes at least one of 4'-amino-azobenzene-4-sulfonic acid, 4-hydroxyazobenzene-4'-sulfonic acid, 4-iodoazobenzene-4'-carboxylic acid, 4-chloroazobenzene-4'-carboxylic acid, 4-dimethylaminoazobenzene-4'-carboxylic acid, and 4-hydroxyazobenzene-4'-carboxylic acid.

[0012] In some embodiments, the thickness of the interface modification layer is 1 to 5 nm.

[0013] In some embodiments, a perovskite solar cell includes a conductive glass, an electron transport layer, an interface modification layer, a perovskite layer, a hole transport layer, and an electrode layer stacked in sequence.

[0014] In some embodiments, the thickness of the electron transport layer is 10 to 50 nm; the thickness of the perovskite layer is 500 to 700 nm; the thickness of the hole transport layer is 100 to 200 nm; and the thickness of the electrode layer is 50 to 150 nm.

[0015] In some embodiments, the conductive glass includes at least one of ITO and FTO; the electron transport layer includes at least one of SnO2, TiO2, and ZnO; the perovskite layer includes a metal halide perovskite, and the crystal structure of the metal halide perovskite is ABX3, wherein A includes at least one of formamidinium ion, methylamine ion, cesium ion, and rubidium ion, B includes at least one of lead ion and tin ion, and X includes at least one of chloride ion, bromide ion, and iodide ion; the hole transport layer includes at least one of Spiro-OMeTAD, PTAA, P3HT, and PEDOT:PSS; and the electrode layer includes at least one of gold, silver, copper, aluminum, carbon, and a transparent conductive oxide.

[0016] In a second aspect of the present invention, a method for modifying the interface of a perovskite solar cell is provided, characterized in that the method comprises the following steps:

[0017] forming an interface modification layer on the surface of the charge transport layer;

[0018] The interface modification layer is formed by at least one of spin coating, dipping, blade coating, and slit coating;

[0019] forming a perovskite layer on the surface of the interface modification layer;

[0020] The interface modification layer includes a multifunctional photoresponsive molecule, the structural formula of which is: ALT,

[0021] A is an anchoring group including at least one of -SO3H, -COOH, -PO3H, -SH, -SiOR, and -SO2Cl; L is a photoresponsive group including at least one of -N=N- and -Ph-N=N-Ph-; and T is a terminal group including at least one of -NH2, -OH, -I, -Cl, -Br, -F, -COOH, -N(CH3)2, and -CN. The preparation method of the present invention is simple, efficient, and cost-effective, thereby enabling the production of a perovskite solar cell with excellent performance.

[0022] In some embodiments, the method of forming an interface modification layer on the surface of a charge transport layer comprises:

[0023] mixing the multifunctional photoresponsive molecule with a solvent to form a solution;

[0024] The solution is coated on the charge transport layer and annealed to form an interface modification layer.

[0025] In some embodiments, the solvent includes at least one of water, ethanol, isopropanol, and chlorobenzene; and / or the concentration of the multifunctional photoresponsive molecule in the solution is 0.05 to 5 mg / mL.

[0026] In some embodiments, the method of forming a coating layer of the solution on the charge transport layer includes a spin coating method, wherein the spin coating method satisfies: a spin coating speed of 1500 to 5000 rpm, and a spin coating time of 20 to 40 s;

[0027] And / or, the annealing treatment satisfies: the annealing temperature is 60-120° C., and the annealing time is 5-20 min.

[0028] Compared with the prior art, the present invention has the following beneficial technical effects:

[0029] The multifunctional molecules contained in the interface modification layer of the present invention can be bonded to the charge transport layer through the anchoring group to passivate the oxygen vacancy defects on the surface of the charge transport layer, and the terminal groups interact with the perovskite layer to form the uncoordinated Pb 2+ The photoresponsive groups undergo repeated cis-trans isomerization under illumination, dynamically driving the upward volatilization of DMSO accumulated at the lower interface, thereby eliminating holes in the perovskite lower interface and improving the interface quality and the crystallization quality of the perovskite film. The perovskite solar cell prepared in this way achieved a high photoelectric conversion efficiency of 24.84%. Furthermore, the cell maintained 91.5% of its initial efficiency after 4500 hours of storage under unencapsulated conditions and 91.2% of its initial efficiency after 700 hours of continuous illumination, enhancing the cell's environmental and light stability.

[0030] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0032] Figure 1 Schematic diagram of the structure of the perovskite solar cell prepared in Example 1 of the present invention;

[0033] Figure 2 This is a UV-visible absorption spectrum of the interface modification layer molecule 4'-amino-azobenzene-4-sulfonic acid used in Example 1 of the present invention in the dark state and under in-situ UV illumination;

[0034] Figure 3 Scanning electron microscope images of the lower surface and cross section of the perovskite of Comparative Example 1, Example 1 and Example 2 of the present invention;

[0035] Figure 4JV (current-voltage) test curves of the perovskite solar cells prepared in Comparative Example 1, Example 1, Example 2, Example 3 and Example 4 measured under the AM1.5 solar spectrum.

[0036] Description of reference numerals:

[0037] 1-conductive glass, 2-electron transport layer, 3-interface modification layer, 4-perovskite layer, 5-hole transport layer, 6-electrode layer. DETAILED DESCRIPTION

[0038] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0039] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, features defined as "first" or "second" may explicitly or implicitly include one or more of such features. Furthermore, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0040] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0041] In this document, the terms “include” or “comprising” are open expressions, that is, including the contents specified in the present invention, but not excluding other contents.

[0042] In a first aspect of an embodiment of the present invention, the present invention provides a perovskite solar cell, comprising: a charge transport layer and a perovskite layer;

[0043] An interface modification layer is provided between the charge transport layer and the perovskite layer;

[0044] The interface modification layer includes a multifunctional photoresponsive molecule, the structural formula of which is: ALT,

[0045] A is an anchoring group including at least one of -SO3H, -COOH, -PO3H, -SH, -SiOR, and -SO2Cl; L is a photoresponsive group including at least one of -N=N- and -Ph-N=N-Ph-; and T is a terminal group including at least one of -NH2, -OH, -I, -Cl, -Br, -F, -COOH, -N(CH3)2, and -CN. The preparation method of the present invention is simple, efficient, and cost-effective, thereby enabling the production of a perovskite solar cell with excellent performance.

[0046] In the present invention, the multifunctional photoisomerization molecules can be bonded to the charge transport layer through the anchoring group to passivate the oxygen vacancy defects on the surface of the charge transport layer, and the terminal groups interact with the perovskite layer to form the uncoordinated Pb 2+ Coordination is performed to optimize the interface energy level structure and promote carrier transport and separation. At the same time, the photoresponsive group undergoes repeated cis-trans isomerization under light, which can dynamically drive the DMSO accumulated at the lower interface to volatilize and discharge upward, thereby eliminating the holes in the lower interface of the perovskite, improving the interface quality and the crystallization quality of the perovskite film. The perovskite solar cell prepared in this way achieved a high photoelectric conversion efficiency of 24.84%. Thus, the perovskite solar cell prepared by the present invention has excellent perovskite crystallization quality and high photoelectric conversion efficiency. In some embodiments of the present invention, the multifunctional photoresponsive molecule includes at least one of 4'-amino-azobenzene-4-sulfonic acid, 4-hydroxyazobenzene-4'-sulfonic acid, 4-iodoazobenzene-4'-carboxylic acid, 4-chloroazobenzene-4'-carboxylic acid, 4-dimethylaminoazobenzene-4'-carboxylic acid, and 4-hydroxyazobenzene-4'-carboxylic acid.

[0047] In some embodiments of the present invention, the thickness of the interface modification layer is 1-5 nm.

[0048] The interface modification layer can directionally and double-sidedly passivate the interface defects between the charge transfer layer and the perovskite layer, while also eliminating DMSO residue on the lower interface, promoting the crystallization process of the perovskite layer and eliminating holes on the lower interface, thereby forming a high-performance perovskite solar cell. This further improves the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0049] As an example, the thickness of the interface modification layer is 1 nm, 1.5 nm, 2 nm, 2.5 nm, 3 nm, 3.5 nm, 4 nm, 4.5 nm, or 5 nm.

[0050] In some embodiments of the present invention, a perovskite solar cell includes a conductive glass, an electron transport layer, an interface modification layer, a perovskite layer, a hole transport layer, and an electrode layer stacked in sequence.

[0051] In some embodiments of the present invention, the thickness of the electron transport layer is 10-50 nm; the thickness of the perovskite layer is 500-700 nm; the thickness of the hole transport layer is 100-200 nm; and the thickness of the electrode layer is 50-150 nm.

[0052] In some embodiments of the present invention, the conductive glass comprises at least one of ITO and FTO; the electron transport layer comprises at least one of SnO2, TiO2, and ZnO; the perovskite layer comprises a metal halide perovskite having an ABX3 crystal structure, wherein A comprises at least one of formamidinium ion, methylamine ion, cesium ion, and rubidium ion; B comprises at least one of lead ion and tin ion; and X comprises at least one of chloride ion, bromide ion, and iodide ion; the hole transport layer comprises at least one of Spiro-OMeTAD, PTAA, P3HT, and PEDOT:PSS; and the electrode layer comprises at least one of gold, silver, copper, aluminum, carbon, and a transparent conductive oxide. This further improves the performance of perovskite solar cells.

[0053] In a second aspect of the embodiments of the present invention, the present invention provides a method for modifying the interface of a perovskite solar cell, characterized in that it includes the following steps:

[0054] forming an interface modification layer on the surface of the charge transport layer;

[0055] The interface modification layer is formed by at least one of spin coating, dipping, blade coating, and slit coating;

[0056] forming a perovskite layer on the surface of the interface modification layer;

[0057] The interface modification layer includes a multifunctional photoresponsive molecule, the structural formula of which is: ALT,

[0058] Wherein, A is an anchoring group including at least one of -SO3H, -COOH, -PO3H, -SH, -SiOR, and -SO2Cl; L is a photoresponsive group including at least one of -N=N- and -Ph-N=N-Ph-; T is an end group including at least one of -NH2, -OH, -I, -Cl, -Br, -F, -COOH, -N(CH3)2, and -CN.

[0059] The preparation method of the present invention is simple, efficient, and cost-controllable, thereby enabling the production of perovskite solar cells with excellent performance.

[0060] In some embodiments of the present invention, a method for forming an interface modification layer on a surface of a charge transport layer includes:

[0061] mixing the multifunctional photoresponsive molecule with a solvent to form a solution;

[0062] The solution is coated on the charge transport layer and annealed to form an interface modification layer.

[0063] In some embodiments of the present invention, the solvent includes at least one of water, ethanol, isopropanol, and chlorobenzene;

[0064] In some embodiments of the present invention, the concentration of the multifunctional photoresponsive molecule in the solution is 0.05-5 mg / mL.

[0065] As an example, the concentrations are 0.05 mg / mL, 0.1 mg / mL, 0.2 mg / mL, 0.5 mg / mL, 1 mg / mL, 2 mg / mL, 3 mg / mL, 4 mg / mL, 5 mg / mL.

[0066] In some embodiments of the present invention, the method of forming a coating layer of the solution on the charge transport layer includes a spin coating method, and the spin coating method satisfies: a spin coating speed of 1500 to 5000 rpm, and a spin coating time of 20 to 40 s;

[0067] As an example, the spin coating speed is 1500 rpm, 2000 rpm, 2500 rpm, 3000 rpm, 3500 rpm, 4000 rpm, 4500 rpm, and 5000 rpm.

[0068] As an example, the spin coating time is 20s, 25s, 30s, 35s, 40s.

[0069] In some embodiments of the present invention, the annealing treatment satisfies the following conditions: the annealing temperature is 60-120° C., and the annealing time is 5-20 min.

[0070] As an example, the annealing temperature is 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, or 120°C.

[0071] As an example, the annealing time is 5 min, 10 min, 15 min, and 20 min.

[0072] In some embodiments of the present invention, before forming the charge transport layer on at least one side of the conductive glass, the conductive glass is further treated, and the treatment method includes:

[0073] The conductive glass was cleaned in detergent, water, acetone, ethanol and isopropyl alcohol in an ultrasonic water bath for 15 minutes, dried, and treated with ultraviolet ozone for 10 to 40 minutes.

[0074] In some embodiments of the present invention, a method for forming an electron transport layer on at least one side of a conductive glass includes:

[0075] The electron transport layer solution is spin-coated on the surface of the conductive glass and annealed to form the electron transport layer; the spin-coating speed is 1000-5000 rpm, the spin-coating time is 10-60 seconds; the annealing temperature is 100-170° C., and the annealing time is 10-40 minutes.

[0076] In some embodiments of the present invention, a method for forming a perovskite layer on the surface of an interface modification layer includes:

[0077] The iodide and the solvent are mixed to form a solution, which is spin-coated on the surface of the interface modification layer at 1500-2500 rpm for 30 seconds, and annealed at 60-80°C for 30-90 seconds to form a porous layer. The iodide comprises PbI2, the additive comprises RbCl, and the solvent comprises DMF (N,N-dimethylformamide) and DMSO (dimethyl sulfoxide), the mass ratio of the two being 9:1, and the concentration of the solution being 1.5 mol / L.

[0078] The organic salt solution is then spin-coated on the surface of the porous layer at 1500-2500 rpm for 30 seconds, and annealed at 120-160°C for 10-15 minutes to form a perovskite layer in an ambient humidity of 20-50 RH%. The organic salt solution includes FAI (iodomethane), MACl (methylammonium chloride), and IPA (isopropyl alcohol), wherein the mass ratio of FAI to MACl is 9:1 and the solution concentration is 0.5 mol / L.

[0079] In some embodiments of the present invention, the iodide layer is subjected to UV irradiation treatment for a time of 10-300 s;

[0080] In some embodiments of the present invention, a method for forming a hole transport layer on a surface of a perovskite layer includes:

[0081] The hole transport layer solution is spin-coated on the surface of the perovskite layer to form a hole transport layer; the spin-coating speed is 3000-6000 rpm, and the spin-coating time is 20-40 seconds.

[0082] In some embodiments of the present invention, the method of forming an electrode layer on the surface of the hole transport layer includes: at least one of: evaporation method, scraping method, and magnetron sputtering method; the evaporation method includes: depositing metal on the surface of the hole transport layer at an evaporation rate of 0.01 to 0.1 nm / s to form an electrode layer.

[0083] Below, the scheme of the present invention will be explained in conjunction with embodiment.It will be understood by those skilled in the art that the following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention.In the embodiment, if specific technology or conditions are not indicated, the technology or conditions described in the literature in this area or the product instructions are used.The reagents or instruments used are not indicated by the manufacturer, and are all conventional products that can be obtained by commercial purchase.

[0084] Example 1

[0085] like Figure 1 As shown in the figure, the perovskite solar cell is made of ITO as a conductive glass substrate, SnO2 as an electron transport layer, 4'-amino-azobenzene-4-sulfonic acid as an interface modification layer, FAPbI3 as a perovskite layer, Spiro-OMeTAD as a hole transport layer, and gold as an electrode layer. The specific preparation steps are as follows:

[0086] (1) Treatment of ITO substrate: The ITO substrate was cut into 20 mm*20 mm pieces by laser etching, and ultrasonically cleaned for 15 minutes using conductive glass cleaning solution, deionized water, acetone, ethanol, and isopropyl alcohol, respectively, and then dried in an oven; treated with ultraviolet ozone equipment for 20 minutes for later use;

[0087] (2) Preparation of the Electron Transport Layer: A SnO2 precursor solution was prepared by mixing a 15 wt.% SnO2 colloidal aqueous solution with deionized water in a volume ratio of 1:4. 100 μL of the SnO2 precursor solution was applied to an ITO substrate at a spin coating speed of 4000 rpm for 30 s. After spin coating, the substrate was annealed at 150°C for 30 minutes to deposit a 30 nm thick SnO2 electron transport layer.

[0088] (3) Preparation of the interface modification layer: First, 0.2 mg of 4'-amino-azobenzene-4-sulfonic acid was weighed and dissolved in 1 mL of deionized water. The mixture was shaken and dispersed for 1 hour. 100 μL of the solution was spin-coated on the electron transport layer prepared in (2) at a speed of 3000 rpm for 30 seconds. After spin coating, the mixture was annealed at 100°C for 15 minutes to deposit a 1 nm thick interface modification layer.

[0089] (4) Preparation of perovskite layer: 691.5 mg of PbI2 was weighed and dissolved in 1 mL of DMF and DMSO mixed solution (V DMF :V DMSO =9:1), 9 mg of RbCl was added to prepare a PbI2 precursor solution; the precursor solution was stirred at 70°C for 3h to ensure complete dissolution; 60 μL was spin-coated on the interface modification layer at a speed of 1500 rpm for 30s, and annealed at 70°C for 60s to obtain a PbI2 porous layer; 180.0 mg of FAI and 30.0 mg of MACl were weighed and dissolved in 2 ml of IPA to prepare an organic salt solution, stirred for 1 hour until completely dissolved, 100 μL was spin-coated on the PbI2 porous layer at a speed of 1800 rpm for 30s, and annealed in air at 150°C for 15 min to obtain a 700 nm thick perovskite layer, and the annealing humidity was 30-40 RH%.

[0090] (5) Preparation of hole transport layer: Weigh 72.3 mg of Spiro-OMeTAD, 30 μL of 4-tert-butylpyridine and 35 μL of lithium salt (Li-TFSI) acetonitrile solution and add them to 1 mL of chlorobenzene to prepare Spiro-OMeTAD hole transport layer solution. The lithium salt acetonitrile solution is prepared by adding 260 mg of Li-TFSI to 1 mL of acetonitrile and shaking until dissolved. Take 60 μL of the hole transport layer solution and spin-coat it on the surface of the perovskite layer prepared in step (4) at a spin coating speed of 5000 rpm for 30 seconds. The resulting hole transport layer thickness is 150 nm.

[0091] (6) Preparation of the electrode layer: Place the device prepared in (5) in a thermal evaporation vacuum coating apparatus to deposit a 80nm thick metal gold electrode (deposited at 0.01nm / s to 10nm, and at 0.04nm / s to 80nm), completing the preparation of the entire perovskite solar cell. Figure 1 The structure shown is an ITO / SnO2 / 4'-amino-azobenzene-4-sulfonic acid / FAPbI3 / Spiro-OMeTAD / Au perovskite solar cell device.

[0092] Example 2

[0093] The difference between Example 2 and Example 1: After the PbI2 porous layer is prepared in step (4) of Example 2, UV treatment is applied for 60s, and UV light is incident from the glass side, and then an organic salt solution is spin-coated on the UV-treated film to complete the preparation of the perovskite layer.

[0094] Example 3

[0095] The difference between Example 3 and Example 2 is that in step (3) of Example 3, 0.05 mg of 4'-amino-azobenzene-4-sulfonic acid was weighed and dissolved in 1 mL of deionized water solvent to prepare the interface modification layer.

[0096] Example 4

[0097] The difference between Example 4 and Example 2 is that in step (3) of Example 4, 1 mg of 4'-amino-azobenzene-4-sulfonic acid was weighed and dissolved in 1 mL of ethanol solvent to prepare the interface modification layer.

[0098] Example 5

[0099] The difference between Example 5 and Example 2 is that in step (3) of Example 5, 0.2 mg of 4-hydroxyazobenzene-4'-sulfonic acid was weighed and dissolved in 1 mL of deionized water solvent to prepare the interface modification layer.

[0100] Example 6

[0101] The difference between Example 6 and Example 2 is that in step (3) of Example 6, 0.2 mg of 4-iodoazobenzene-4'-carboxylic acid was weighed and dissolved in 1 mL of deionized water solvent to prepare the interface modification layer.

[0102] Example 7

[0103] The difference between Example 7 and Example 2 is that in step (3) of Example 7, 0.2 mg of 4-chloroazobenzene-4'-carboxylic acid was weighed and dissolved in 1 mL of deionized water solvent to prepare the interface modification layer.

[0104] Example 8

[0105] The difference between Example 8 and Example 2 is that in step (3) of Example 8, 0.2 mg of 4-dimethylaminoazobenzene-4'-carboxylic acid was weighed and dissolved in 1 mL of deionized water solvent to prepare the interface modification layer.

[0106] Example 9

[0107] The difference between Example 9 and Example 2 is that in step (3) of Example 9, 0.2 mg of 4-hydroxyazobenzene-4'-carboxylic acid was weighed and dissolved in 1 mL of deionized water solvent to prepare the interface modification layer.

[0108] Comparative Example 1

[0109] The difference between Comparative Example 1 and Example 1 is that in Comparative Example 1, step (3) of preparing the interface modification layer is omitted, and step (4) is directly performed after step (2) of Example 1.

[0110] Experimental results analysis:

[0111] Figure 2 This is the UV-visible absorption spectrum of the interface-modifying molecule 4'-aminoazobenzene-4-sulfonic acid used in Example 1. The absorption peak at ~412 nm corresponds to the trans isomer, and the absorption peak at ~452 nm corresponds to the cis isomer. Under in situ UV illumination, the absorption curve changes significantly compared to the dark state, with a significant decrease in the trans isomer content and a rapid decline in the cis isomer content, indicating that UV illumination can induce the transition from the trans isomer to the cis isomer.

[0112] Figure 3The following are scanning electron microscope images of the lower surface and cross section of the perovskite film in Comparative Example 1, Example 1 and Example 2. In Comparative Example 1, a large number of holes are present on the lower surface of the perovskite film, which is caused by the residue of DMSO. The number of holes in Example 1 has decreased, indicating that the modification of the multifunctional photoresponsive molecules can reduce the DMSO residue to a certain extent. Further, the holes on the lower surface of the perovskite film in Example 2 are eliminated, indicating that the photoresponsive process using the multifunctional photoresponsive molecules can significantly reduce the DMSO residue at the lower interface of the perovskite, and the quality of the perovskite film is effectively improved. Thus, it is shown that the multifunctional photoresponsive molecules in the interface modification layer of the present invention can effectively eliminate the holes on the lower surface of the perovskite, thereby forming a perovskite solar cell with good performance, further improving the photoelectric conversion efficiency of the perovskite solar cell.

[0113] The current-voltage characteristic curves of the perovskite solar cells of Examples 1-9 and Comparative Example 1 were tested under the AM1.5 solar spectrum. The results are shown in Tables 1 and Figure 4 As shown, the efficiency of the perovskite solar cell of Example 1 modified with 4'-amino-azobenzene-4-sulfonic acid is as high as 24.42%, which is 2.65% higher than the efficiency of the unmodified perovskite solar cell of Comparative Example 1 of 21.77%. The efficiency improvement is mainly reflected in the open circuit voltage (V OC ) and fill factor (FF). The perovskite solar cell in Example 2, after UV treatment, further improved to 24.84%, primarily due to reduced DMSO residue, which improved interface and crystal quality. In Examples 3 and 4, however, when the 4'-aminoazobenzene-4-sulfonic acid concentration was decreased or increased, the perovskite solar cell performance decreased due to poor molecular coverage and molecular aggregation. This demonstrates that the perovskite solar cell of the present invention has excellent photoelectric conversion efficiency.

[0114] Table 1 Main performance parameters of perovskite solar cells in Comparative Example 1 and Examples 1-9

[0115] <![CDATA[J SC (mAcm -2 )]]> <![CDATA[V OC (V)]]> FF(%) PCE (%) Comparative Example 1 25.27 1.153 74.69 21.77 Example 1 25.76 1.165 81.37 24.42 Example 2 25.79 1.173 82.11 24.84 Example 3 25.35 1.176 80.19 23.90 Example 4 25.35 1.164 75.24 22.20 Example 5 25.60 1.179 79.86 24.10 Example 6 25.60 1.190 79.21 24.14 Example 7 25.51 1.183 81.68 24.66 Example 8 25.02 1.177 78.17 23.01 Example 9 25.20 1.171 78.27 23.10

[0116] Table 2 shows the environmental stability and light stability tests for Examples 1-9 and Comparative Example 1. After the unencapsulated perovskite solar cell was placed in an atmospheric environment with a relative humidity of 30-40% and a temperature of 25°C for 4500 hours, the efficiency of Comparative Example 1 dropped to 71.9%, while the efficiency of Example 2 remained stable at 91.5% after 4500 hours of storage. The improvement in environmental stability mainly comes from the improvement in the quality of the perovskite interface. After the cell was placed under an LED light with a single sunlight intensity for 700 hours of continuous illumination, the efficiency of Comparative Example 1 dropped to 70.7%, while the efficiency of Example 2 maintained at 91.2%. The improvement in light stability mainly comes from the elimination of buried interface holes and the enhancement of interface bonding strength. This shows that the perovskite solar cell of the present invention has excellent stability.

[0117] Table 2 Stability of perovskite solar cells in Comparative Example 1 and Examples 1-9

[0118]

[0119] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0120] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A perovskite solar cell, characterized in that include: Charge transport layer and perovskite layer; An interface modification layer is provided between the charge transport layer and the perovskite layer; The interface modification layer includes a multifunctional photoresponsive molecule, the structural formula of which is: ALT Wherein, A is an anchoring group including at least one of -SO3H, -COOH, -PO3H, -SH, -SiOR, and -SO2Cl; L is a photoresponsive group including at least one of -N=N- and -Ph-N=N-Ph-; T is an end group including at least one of -NH2, -OH, -I, -Cl, -Br, -F, -COOH, -N(CH3)2, and -CN.

2. The perovskite solar cell according to claim 1, characterized in that The multifunctional molecule includes at least one of 4'-amino-azobenzene-4-sulfonic acid, 4-hydroxyazobenzene-4'-sulfonic acid, 4-iodoazobenzene-4'-carboxylic acid, 4-chloroazobenzene-4'-carboxylic acid, 4-dimethylaminoazobenzene-4'-carboxylic acid, and 4-hydroxyazobenzene-4'-carboxylic acid.

3. The perovskite solar cell according to claim 1 or 2, characterized in that The thickness of the interface modification layer is 1 to 5 nm.

4. The perovskite solar cell according to claim 1 or 2, characterized in that The perovskite solar cell comprises conductive glass, an electron transport layer, an interface modification layer, a perovskite layer, a hole transport layer and an electrode layer which are stacked in sequence.

5. The perovskite solar cell according to claim 4, characterized in that The thickness of the electron transport layer is 10 to 50 nm; the thickness of the perovskite layer is 500 to 700 nm; the thickness of the hole transport layer is 100 to 200 nm; and the thickness of the electrode layer is 50 to 150 nm.

6. The perovskite solar cell according to claim 4, characterized in that The conductive glass includes at least one of ITO and FTO; the electron transport layer includes at least one of SnO2, TiO2, and ZnO; the perovskite layer includes a metal halide perovskite, and the crystal structure of the metal halide perovskite is ABX3, wherein A includes at least one of formamidinium ion, methylamine ion, cesium ion, and rubidium ion, B includes at least one of lead ion and tin ion, and X includes at least one of chloride ion, bromide ion, and iodide ion; the hole transport layer includes at least one of Spiro-OMeTAD, PTAA, P3HT, and PEDOT:PSS; and the electrode layer includes at least one of gold, silver, copper, aluminum, carbon, and a transparent conductive oxide.

7. A method for modifying the interface of a perovskite solar cell, characterized in that: The following steps are involved: forming an interface modification layer on the surface of the charge transport layer; forming a perovskite layer on the surface of the interface modification layer; The interface modification layer includes a multifunctional photoresponsive molecule, and the structural formula of the multifunctional photoresponsive molecule is: ALT Wherein, A is an anchoring group including at least one of -SO3H, -COOH, -PO3H, -SH, -SiOR, and -SO2Cl; L is a photoresponsive group including at least one of -N=N- and -Ph-N=N-Ph-; T is an end group including at least one of -NH2, -OH, -I, -Cl, -Br, -F, -COOH, -N(CH3)2, and -CN.

8. The interface modification method according to claim 7, characterized in that: The method for forming an interface modification layer on the surface of the charge transport layer comprises: mixing the multifunctional photoresponsive molecule with a solvent to form a solution; The solution is coated on the charge transport layer and subjected to annealing treatment to form an interface modification layer.

9. The preparation method according to claim 8, characterized in that The solvent includes at least one of water, ethanol, isopropanol, and chlorobenzene; And / or, the concentration of the multifunctional photoresponsive molecule in the solution is 0.05-5 mg / mL.

10. The interface modification method according to claim 8 or 9, characterized in that: The method of forming a coating layer of the solution on the charge transport layer includes a spin coating method, wherein the spin coating method satisfies: a spin coating speed of 1500 to 5000 rpm and a spin coating time of 20 to 40 s; And / or, the annealing treatment satisfies: the annealing temperature is 60-120° C., and the annealing time is 5-20 min.

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