A tin-lead mixed perovskite thin film, a preparation method and application thereof

Abstract

The application discloses a kind of tin lead mixed perovskite film and preparation method thereof, the tin lead mixed perovskite film is composed of perovskite intrinsic layer and antioxidant layer;Perovskite intrinsic layer is prepared by solution method after adding a certain proportion of main antioxidant in tin lead mixed perovskite precursor solution, and antioxidant layer is prepared by wet coating with antioxidant solution.The application adds main antioxidant in precursor solution, and deposits a layer of antioxidant on the surface of perovskite intrinsic layer after crystallization, effectively passivates the surface and internal defects of perovskite film through the synergistic effect of main antioxidant and antioxidant, improves the quality of tin lead mixed perovskite film, improves the uniformity of perovskite film, and due to the synergistic effect of main antioxidant and antioxidant, effectively removes the oxygen free radicals adsorbed by deep level defects of perovskite film and the influence of oxygen in air on perovskite film, greatly improves the stability of tin lead mixed perovskite film.

Description

Technical Field

[0001] This invention belongs to the field of solar cell technology, specifically relating to a tin-lead mixed perovskite thin film and its preparation method. Background Technology

[0002] Perovskite solar cells are a third-generation thin-film battery that uses organic-inorganic hybrid perovskite materials as the light-absorbing layer. They have attracted significant attention from academia and industry due to their advantages such as low cost, simple fabrication process, and excellent photoelectric conversion efficiency. Meanwhile, with the rapid development of the photovoltaic industry, the industrial efficiency of PERC cells has reached 23.5%, approaching the 24% efficiency limit. In contrast, the efficiency of novel crystalline silicon cells is limited by the Schottky limit of 29.4%, making further efficiency improvements difficult.

[0003] As a rising star in the photovoltaic industry, perovskite solar cells have undergone rapid development over the past 13 years. The photoelectric conversion efficiency of single-junction cells has increased from 3.8% to 25.7%, and stability has also been greatly improved. Furthermore, the efficiency of perovskite / perovskite tandem cells (all-calcium tandem) has even surpassed 28.0%, exceeding the record of 26.7% set by monocrystalline silicon cells. Therefore, perovskite materials are hailed as a revolutionary new material for the photovoltaic industry.

[0004] The all-calcium tandem perovskite solar cell consists of a top cell and a bottom cell, which absorb short-wavelength and long-wavelength light, respectively. The top cell is fabricated from a narrow-bandgap perovskite material mixed with tin and lead. The bandgap is optimized by adjusting the tin-lead ratio in the perovskite precursor solution. However, since the tin in the tin-lead mixed perovskite is +2 tin, it is easily oxidized to +4 tin in air. Existing all-calcium tandem solar cells require measures to prevent the Sn in the precursor solution from being oxidized. 2+ Oxidation to Sn 4+ Typically, the fabrication of narrow bandgap perovskite solar cells is carried out in a glove box environment, which isolates water and oxygen. A 2D perovskite barrier layer is then fabricated on this 3D film to further isolate the 3D film from the influence of water and oxygen. However, the 2D perovskite barrier layer is usually doped at the A-site of a large molecule, which inevitably leads to a decrease in the performance of the all-calcium tandem solar cell. Therefore, how to incorporate Sn... 2+ Oxidation to Sn 4+ This has become the most important aspect of all-calcium tandem batteries. Summary of the Invention

[0005] To address the shortcomings of tin-lead mixed perovskite films, such as poor quality, poor film coverage, and easy oxidation of precursor solutions, this invention provides a solution that improves the uniformity of perovskite film preparation, enhances crystal quality, and facilitates subsequent Sn... 2+ Solutions that do not oxidize are used to improve the photoelectric conversion efficiency and stability of tin-lead hybrid perovskite and all-calcium tandem solar cells.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A tin-lead hybrid perovskite thin film, consisting of an intrinsic perovskite layer and an antioxidant layer; The intrinsic perovskite layer is prepared by adding a certain proportion of primary antioxidant to a tin-lead mixed perovskite precursor solution and then using a solution method. The antioxidant layer is prepared by wet coating of a co-antioxidant solution. The primary antioxidant is a hindered phenolic antioxidant or an amine antioxidant, and the secondary antioxidant is a phosphite antioxidant or a thioester antioxidant.

[0007] Furthermore, the perovskite material in the tin-lead mixed perovskite precursor solution has an ABX3 crystal structure, where A is Cs. + CH(NH2) 2+ CH3NH3 + C(NH2)3 + At least one, two, or three of the above are mixed in any proportion, wherein B is Pb. 2 + Sn 2+ Blending or Sn in 2+ One of them, in which Sn in tin-lead blend 2+ The ratio is any proportion between 1 and 100%, where X is Br - I - Cl - At least one of them Furthermore, the hindered phenolic primary antioxidant can be an alkyl monophenol or an alkyl polyphenol, wherein the alkyl monophenol includes, but is not limited to, 2,6-di-tert-butyl-4-methylphenol, octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 2,6-di-tert-butyl-p-cresol, isooctyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate, 4,6-bis(octylthiomethyl)o-cresol, and 4-[(4,6-dioctylthio-1,3-methyl-4-hydroxyphenyl)-co-cresol. [5-Triazine-2-yl)amino]-2,6-Di(1,1-methylethyl)phenol; alkyl polyphenols include, but are not limited to, 2,2-methylenebis(4-methyl-6-tert-butylphenol), pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyhydrocinnamic acid), 4,4'-thiobis(3-methyl-6-tert-butylphenol), hydroquinone, and hexane-1,6-diylbis(3-(3,5-di-tert-butyl) 4-hydroxyphenyl)propionate, triethylene glycol ether-di(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate, 2,2'-thiobis(4-methyl-6-tert-butylphenol), di[3,5-di-(1,1-dimethylethyl)-4-hydroxy-]phenylpropionate thiadiglycol ester, N,N'-1,3-propylene di[3,5-di-tert-butyl-4-hydroxyphenylpropionamide], 1,2-bis[β-( 3,5-Di-tert-butyl-4-hydroxyphenyl)propionylhydrazine, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione.

[0008] Furthermore, the amine antioxidants include, but are not limited to, 1-naphthylaminobenzene, N-phenyl-2-naphthylamine, 4,4'-dioctyldiphenylamine, p-phenylene di-2-naphthylamine, N,N′-diisooctyl-p-phenylenediamine, N,N'-di-sec-butyl-p-phenylenediamine, N-phenyl-N′-sec-butyl-p-phenylenediamine, diisooctyldiphenylamine, dinonyldiphenylamine, dialkyldiphenylamine, bisoctyldiphenylamine, butyloctyldiphenylamine, dinonyldiphenylamine, N-phenyl-α-naphthylamine, phenyl-α-naphthylamine, octylphenyl-α-naphthylamine, dialkyldiphenylamine, 3,7-di-tert-octylphenothiazine, or phenothiazine.

[0009] Furthermore, the phosphite antioxidants include, but are not limited to, tris(2,4-di-tert-butylphenyl) phosphite, bis[2-methyl-4,6-bis(1,1'-dimethylethyl)phenol] ethyl phosphate, tetra(2,4-di-tert-butyloctaalkoxy-4,4-biphenyl) phosphate, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, (2,4,6-tri-tert-butylphenyl-2-butyl-2-ethyl)-1,3-propanediol phosphite, di(2,4-di-p-isopropylphenyl) pentaerythritol diphosphite, 2,2'-ethylidene bis(4,6-di-tert-butylphenyl) fluorophosphite, tetra(2,4-di-tert-butylphenyl-4,4-biphenyl) diphosphate, and spiroethylene glycol di[2,2'-methylenebis(4,6-di-tert-butylphenyl)] phosphite.

[0010] Furthermore, the thioester-based antioxidants include, but are not limited to, dodecyl thiodipropionate, pentaerythritol tetra(3-lauryl thiopropionate), di(tetradecyl) 3,3'-thiodipropionate, methyl 2,2-thiobis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 4,4'-thiobis(6-tert-butyl-m-cresol), thiobis(3,5-di-tert-butyl-4-hydroxybenzyl), and 4,4'-thiobis(2-methyl-6-tert-butylphenol).

[0011] Furthermore, the amount of the main antioxidant added to the tin-lead mixed perovskite precursor solution is 0.01%-10% of the sum of the molar amounts of lead ions and tin ions in the precursor solution.

[0012] Furthermore, the concentration of the antioxidant layer is 1 mg / mL to 200 mg / mL, and the solvent used is one or more mixed solvents of toluene, chlorobenzene, ethanol, isopropanol, butanol, ethyl acetate, chloroform, butyl acrylate, dichlorobenzene, α,α,α-trifluorotoluene, anisole, diethyl ether, m-xylene, and 2,4,6-trimethylbenzene.

[0013] This invention provides a method for preparing a tin-lead mixed perovskite thin film, characterized by comprising the following steps: S1: Add the primary antioxidant to the tin-lead mixed perovskite solvent according to the stated addition ratio, and heat to dissolve. S2: Prepare the tin-lead mixed perovskite precursor solution according to conventional methods; S3: The perovskite precursor liquid obtained in S2 is coated by any one of spin coating, slot coating, scraping, roller coating or spraying, and then heated to obtain the intrinsic layer of tin-lead mixed perovskite. S4: Add the antioxidant to the solvent in a certain amount; S5: The perovskite precursor liquid obtained in S2 is applied by any one of the following methods: spin coating, slot coating, blade coating, roller coating or spray coating, and then heated to obtain an antioxidant layer.

[0014] Compared with existing technologies, this invention adds a primary antioxidant to the precursor solution and deposits a co-antioxidant layer on the surface of the intrinsic perovskite layer after crystallization. Through the synergistic effect of the primary antioxidant and the co-antioxidant, surface and bulk defects of the perovskite film are effectively passivated, improving the film quality and uniformity of the tin-lead mixed perovskite film. At the same time, due to the synergistic effect of the primary antioxidant and the co-antioxidant, the damage of oxygen free radicals adsorbed by deep-level defects of the perovskite film, oxygen in the air to the perovskite film, and the influence of residual free radicals in the film during the lamination process on the perovskite are effectively eliminated, greatly improving the stability of the tin-lead mixed perovskite film. Attached Figure Description

[0015] Figure 1 This is a flowchart of the process for preparing tin-lead mixed perovskite thin films according to the present invention.

[0016] Figure 2 This is a comparison chart of device performance between Example 1 (control group) and Example 2 group of the present invention. Detailed Implementation

[0017] For the preparation of tin-lead mixed perovskite thin films, Sn 2+ It is easily oxidized to Sn 4+ This leads to problems such as poor crystallinity of tin-lead mixed perovskite films, low film coverage, and easy damage to the perovskite films during lamination. This invention addresses these issues by adding a primary antioxidant to the perovskite precursor solution to prepare the film, and depositing a co-antioxidant layer on the film surface. Under the action of the primary antioxidant, the oxidized Sn... 4+ Restored to Sn 2+ Furthermore, during film formation, oxygen free radicals adsorbed at the defect energy levels of the perovskite were eliminated, thus avoiding the impact of oxygen generation on the perovskite. At the same time, the deposition of the antioxidant on the surface of the intrinsic perovskite layer prevented damage to the perovskite film from oxygen in the air. Under the synergistic effect of the main antioxidant and the antioxidant, the damage to the perovskite film caused by the free radical initiator remaining in the cross-linked film during the lamination process was also eliminated. Finally, a large-area stable tin-lead hybrid perovskite solar cell was obtained.

[0018] The present invention discloses a tin-lead mixed perovskite thin film comprising an intrinsic perovskite layer and an antioxidant layer. The intrinsic perovskite layer is obtained by solution method using a tin-lead mixed perovskite precursor solution containing a certain proportion of a primary antioxidant. The antioxidant layer is obtained by wet coating after compounding a co-antioxidant. The primary antioxidant is a hindered phenol or amine antioxidant, and the co-antioxidant is a phosphite or thioether antioxidant.

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but this should not be construed as limiting the present invention. Any modifications or substitutions made to the methods, steps, or conditions of the present invention without departing from the spirit and substance of the invention are within the scope of the present invention. Experimental methods and reagents not specifically described in the embodiments are performed according to conventional conditions in the art.

[0020] Example 1 (Control Group) Perovskite intrinsic layer: MA 0.5 FA 0.5 Pb 0.3 Sn 0.7 I3, The method for preparing the tin-lead mixed perovskite thin film is characterized by comprising the following steps: S1: In a glove box protected by nitrogen or argon, according to the stoichiometric ratio MA 0.5 FA 0.5 Pb 0.3 Sn 0.7 I3 was weighed out according to the appropriate mass of the drug and dissolved in a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) in a volume ratio of 4:1. The solution was stirred overnight at 70°C to prepare a 1.5M tin-lead mixed perovskite precursor solution. S2: The perovskite precursor solution obtained in S1 is used to obtain a perovskite wet film by slit coating. S3: The wet film obtained in S2 is placed in the antisolvent solution of S2 for extraction for 10 min, and then annealed at 100℃ for 20 min to obtain a tin-lead mixed perovskite film.

[0021] S4: Solar cells with a device structure of ITO / NiOx / perovskite / C60 / BCP / ITO are prepared by the above method.

[0022] Example 2 Perovskite intrinsic layer: MA 0.3 FA 0.7 Pb 0.5 Sn 0.5 I3, Primary antioxidant: 2,2'-methylenebis(6-tert-butyl-4-methylphenol), added at a dosage of 5% (Pb). 2+ and Sn 2+ (molar ratio) Antioxidant: Disodecyl thiodipropionate, dosage 20 mg / mL, solvent: toluene. The method for preparing the tin-lead mixed perovskite thin film includes the following steps: S1: Add 2,2'-methylenebis(6-tert-butyl-4-methylphenol) (addition dosage 5% (Pb)) in a glove box protected by nitrogen or argon. 2+ and Sn 2+ The solution was dissolved in a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) in a volume ratio of 4:1. S2: In a glove box protected by nitrogen or argon, according to the stoichiometric ratio MA 0.3 FA 0.7 Pb 0.5 Sn 0.5 Weigh out the appropriate amount of reagent I3 and dissolve it in the solution obtained from S1. Stir overnight at 70°C to prepare a 1.5M tin-lead mixed perovskite precursor solution. S3: Dissolve the antioxidant disodecyl thiodipropionate in toluene solution at a ratio of 20 mg / mL; S4: Take 20 μL of the perovskite precursor solution obtained in S2 and spin-coat it. During the spin-coating process, add 200 μL of the antisolvent S3. After annealing at 100 °C, a tin-lead mixed perovskite film is obtained.

[0023] S5: A solar cell with a device structure of ITO / NiOx / perovskite / C60 / BCP / ITO is prepared by the above method.

[0024] Example 3 Perovskite intrinsic layer: MA 0.5 FA 0.5 Pb 0.3 Sn 0.7 I3, Main antioxidant: N,N′-diisooctyl-p-phenylenediamine, added at a dosage of 2% (Pb 2+ and Sn 2+ (molar ratio) Antioxidant: Tris(2,4-di-tert-butylphenyl) phosphite, dosage 10 mg / mL, solvent: chlorobenzene. The method for preparing the tin-lead mixed perovskite thin film is characterized by comprising the following steps: S1: Add N,N′-diisooctyl-p-phenylenediamine (addition dose of 2% (Pb)) to a glove box protected by nitrogen or argon. 2+ and Sn 2+ The solution was dissolved in a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) in a volume ratio of 3:1. S2: In a glove box protected by nitrogen or argon, according to the stoichiometric ratio MA 0.5 FA 0.5 Pb0.3 Sn 0.7 Weigh out the appropriate mass of the reagent (I3) and dissolve it in the solution obtained in S1. Stir overnight at 70°C to prepare a 1.8M tin-lead mixed perovskite precursor solution. S3: Dissolve the antioxidant disodecyl thiodipropionate in toluene solution at a ratio of 10 mg / mL; S4: The perovskite precursor solution obtained in S2 is used to obtain a perovskite wet film by slit coating. S5: The wet film obtained in S4 is placed in the antisolvent solution of S2 for extraction for 10 min, and then annealed at 100℃ for 20 min to obtain a tin-lead mixed perovskite film.

[0025] S6: A solar cell with a device structure of ITO / NiOx / perovskite / C60 / BCP / ITO is prepared by the above method.

[0026] By comparing Examples 1 and 2 ( Figure 2 As shown in the figure, by adding a primary antioxidant to the precursor solution and depositing a co-antioxidant layer on the surface of the intrinsic perovskite layer after crystallization, the surface and bulk defects of the perovskite film are effectively passivated through the synergistic effect of the primary antioxidant and the co-antioxidant. This improves the film quality of the tin-lead mixed perovskite and enhances the uniformity of the perovskite film. At the same time, due to the synergistic effect of the primary antioxidant and the co-antioxidant, the oxygen free radicals adsorbed by deep-level defects of the perovskite film, the damage of oxygen in the air to the perovskite film, and the influence of residual free radicals in the film during the lamination process on the perovskite are effectively eliminated. Ultimately, this improves the photoelectric performance of the perovskite solar cell and greatly enhances the stability of the tin-lead mixed perovskite film.

Claims

1. A tin-lead mixed perovskite thin film, characterized in that: It consists of an intrinsic perovskite layer and an antioxidant layer; The intrinsic perovskite layer is prepared by solution method by adding a certain proportion of main antioxidant to a tin-lead mixed perovskite precursor solution. The amount of main antioxidant added to the tin-lead mixed perovskite precursor solution is 0.01%-10% of the sum of the molar amounts of lead ions and tin ions in the precursor solution. The antioxidant layer is prepared by wet coating of an antioxidant solution. The primary antioxidant is a hindered phenolic antioxidant or an amine antioxidant, selected from 2,2'-methylenebis(6-tert-butyl-4-methylphenol) or N,N′-diisooctyl-p-phenylenediamine; The antioxidant is a phosphite antioxidant or a thioester antioxidant, selected from dodecyl thiodipropionate or tris(2,4-di-tert-butylphenyl) phosphite.

2. The tin-lead mixed perovskite thin film according to claim 1, characterized in that: The perovskite material in the tin-lead mixed perovskite precursor solution has an ABX3 crystal structure, where A is Cs. + CH(NH2) 2+ CH3NH3 + C(NH2)3 + At least one, two, or three of the above are mixed in any proportion, wherein B is Pb. 2+ Sn 2+ Blending or Sn in 2+ One of them, in which Sn in tin-lead blend 2+ The ratio is any proportion between 1 and 100%, where X is Br - I - Cl - At least one of them.

3. The tin-lead mixed perovskite thin film according to claim 1, characterized in that: The concentration of the antioxidant layer is 1 mg / mL to 200 mg / mL, and the solvent used is one or more of the following: toluene, chlorobenzene, ethanol, isopropanol, butanol, ethyl acetate, chloroform, butyl acrylate, dichlorobenzene, α,α,α-trifluorotoluene, anisole, diethyl ether, m-xylene, or 2,4,6-trimethylbenzene.

4. The method for preparing the tin-lead mixed perovskite thin film according to claim 1, characterized in that, Includes the following steps: S1: Add the primary antioxidant to the tin-lead mixed perovskite solvent according to the specified ratio, and heat to dissolve. S2: Prepare the tin-lead mixed perovskite precursor solution according to conventional methods; S3: The perovskite precursor liquid obtained in S2 is coated by any one of spin coating, slot coating, scraping, roller coating or spraying, and then heated to obtain the intrinsic layer of tin-lead mixed perovskite. S4: Add the antioxidant to the solvent in a certain amount; S5: The perovskite precursor liquid obtained in S2 is applied by any one of the following methods: spin coating, slot coating, blade coating, roller coating or spray coating, and then heated to obtain an antioxidant layer.

5. A perovskite solar cell, comprising the tin-lead mixed perovskite thin film of claim 1 or the tin-lead mixed perovskite thin film prepared by the method of claim 4.

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