A preparation method of perovskite layer interface modifier, and interface modifier

Abstract

The present application provides a method for preparing a perovskite layer interface modifier and an interface modifier. The preparation method adopts a multi-metal synergistic coordination strategy, and introduces a multi-site coordination ability containing a thiol group (-SH) multifunctional ligand and two or more metal ions with complementary electronic structures to form a multi-metal thiol synergistic coordination solution as an interface modifier for the perovskite layer. After the interface modifier is spin-coated on the perovskite layer and annealed, the formed interface modification layer not only has self-repairing and dynamic regulation functions (the weak coordination bonds between the thiol group and the various metal ions can be broken and reorganized when stress or environmental changes occur), but also can regulate the acid-base environment of the perovskite surface under the synergistic action of multiple metals, reduce the migration of halide ions, inhibit interface degradation, and prevent moisture and oxygen from penetrating into the perovskite layer. The interface modifier provided in the present application has a dual repair effect of defect filling and interface reconstruction.

Description

Technical Field

[0001] The present application relates to the field of performance optimization of perovskite battery components or perovskite raw materials, and specifically to an interface modifier used as a perovskite layer in a perovskite solar cell and a preparation method thereof. Background Art

[0002] Solar cells are photoelectric semiconductor sheets that use sunlight to generate electricity directly. They convert light energy into electrical energy directly through the photoelectric effect or photochemical effect. They have the advantages of high reliability, long life, and high conversion efficiency. With the development of technology, the conversion efficiency of solar cells has been continuously improved, the preparation cost has been continuously reduced, and photovoltaic power generation technology has achieved partial commercial application.

[0003] Perovskite cells are solar cells based on perovskite structural materials as light absorption layers. This type of cell has attracted widespread attention in the photovoltaic field due to its high efficiency and low-cost manufacturing potential. Perovskite materials have a chemical formula of ABX3, where the A position is usually methylamine ion (CH3NH3+) or a similar organic cation, the B position is lead ion (Pb2+), and the X position is a halogen ion such as iodide ion (I-). This unique crystal structure gives perovskite materials excellent photoelectric properties, such as high absorption coefficient and long carrier diffusion length, making them ideal photovoltaic conversion materials. In recent years, researchers have continuously optimized the design and preparation process of perovskite cells, including improving electrode materials, interface modification, device structure design, etc., to improve their energy conversion efficiency and stability. At present, the highest efficiency of laboratory-level perovskite cells has exceeded 25%, approaching or even surpassing traditional silicon-based solar cells, and there is still a lot of room for development.

[0004] However, it is worth noting that although perovskite cells have shown great application prospects, they still face some challenges in the actual commercialization process, such as long-term stability and environmental tolerance (for example, acid and alkali corrosion resistance, light aging resistance, etc.) and other issues need to be further resolved. Therefore, how to improve the structural stability and density of the perovskite layer (waterproof and gas infiltration proof) and reduce or reduce the defects on the surface of the perovskite layer are both hot topics in current perovskite cell research. The current mainstream solution is to spin-coat a layer of interface modifier on the surface of the perovskite layer (on the market, interface repair agents based on self-assembly molecules are the current mainstream interface modifiers), and reduce the surface defects of the perovskite layer and improve its density through passivation or repair of the interface. However, there is still a problem that the interface improvement effect is not satisfactory, and it is impossible to improve the environmental tolerance of the perovskite layer and the ability to inhibit interface degradation. Summary of the invention

[0005] In view of the above-mentioned deficiencies of the existing perovskite layer interface repair agent, the present application provides a method for preparing a perovskite interface repair agent and an interface repair agent. The preparation method is based on a multi-metal synergistic coordination strategy, and introduces a multi-site coordination ability-containing thiol group (-SH) multifunctional ligand to coordinate two or more metal ions with complementary electronic structures to produce an interface modifier. The interface modifier has the dual effects of defect filling and interface reconstruction. When it is used to modify the perovskite layer, a dynamic and stable interface regulation layer is formed on the surface of the perovskite layer. The interface regulation layer can not only realize the interface repair and acid-base environment regulation of the perovskite layer, but also can reduce the migration of halide ions and inhibit interface degradation based on the synergistic effect of multiple metals.

[0006] The first aspect of the present application provides a method for preparing a perovskite layer interface modifier. The preparation method comprises: putting a multifunctional ligand containing a thiol group (-SH) with multi-site coordination ability, a salt substance 1 having a metal ion 1, and a salt substance 2 having a metal ion 2 into a polar solvent in a material ratio of 1:2:2 between the thiol group (-SH), the metal ion 1, and the metal ion 2, and uniformly mixing them to form a multi-metal thiol coordinated coordination solution as the perovskite layer interface modifier; the metal ion 1 and the metal ion 2 have complementary electronic structures.

[0007] In order to ensure the stability and dynamics of multi-metal coordinated coordination, thiol molecules with multi-site coordination ability are selected. Such thiol molecules include but are not limited to: 2,3-dimercaptosuccinic acid (DMSA), 1,3-propanedithiol and polythiol polymers. Among them, 2,3-dimercaptosuccinic acid (DMSA) can provide strong adsorption and high dynamics; 1,3-propanedithiol is suitable for environmentally sensitive film passivation; polythiol polymers improve interface strength and ductility.

[0008] Further, the polar solvent includes at least one of N, N-dimethylformamide or isopropanol. Preferably, the polar solvent is prepared by N-dimethylformamide (DMF) and isopropanol (IPA) in a volume ratio of 3:2.

[0009] Furthermore, the multifunctional ligand is present in the form of a solution having a thiol group (-SH) concentration of 0.05M / L to 0.1M / L. The metal ion 1 is or , metal ion 2 is or ; The substance salt 1 and the substance salt 2 are acetate or nitrate.

[0010] Furthermore, the preparation method further comprises: after putting the multifunctional ligand, the metal ion 1 and the salt substance 2 into the polar solvent, stirring sufficiently to uniformly mix the metal ion 1, the metal ion 2 and the multifunctional ligand.

[0011] Corresponding to the above preparation method, the second aspect of the present application further provides an interface modifier for a perovskite layer, wherein the interface modifier is a multi-metal thiol coordinated coordination solution prepared by the above preparation method for the interface modifier for a perovskite layer.

[0012] In addition, the present application also provides a method for preparing a perovskite film. The method comprises: preparing a perovskite layer at After annealing for a preset time, the polymetallic thiol coordinated coordination solution is spin-coated on the surface of the perovskite layer at a rotation speed of 2000 rpm to form a uniformly covered thin film layer as an interface layer; then, - The heat treatment is performed within a certain range to promote the formation of the dynamic coordination network of the interface layer and enhance its adhesion.

[0013] The interface modifier obtained by the technical solution provided in this application has the dual effects of defect filling and interface reconstruction on the surface of the perovskite layer. The interface modifier can achieve the self-repair function and dynamic regulation function of the perovskite surface by virtue of the mechanism that the weak coordination bonds between the thiol group and various metal ions can be broken and reorganized when stress or environmental changes occur; under the synergistic effect of multiple metals, the acid-base environment of the perovskite surface can also be regulated, reducing the migration of halide ions in the perovskite layer, inhibiting interface degradation, and improving the resistance of the perovskite layer to light aging. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0015] Figure 1 A flowchart of a method for preparing a perovskite layer modifier in one embodiment is provided for the present application. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0017] In such Figure 1 In one embodiment shown, the preparation method of the perovskite layer interface modifier provided in the present application mainly includes the following steps: S1. Prepare polar solvent; The polar solvent includes at least one of N, N-dimethylformamide or isopropyl alcohol. Of course, other commonly used polar solvents are also possible. Preferably, the polar solvent is prepared by using N-dimethylformamide (DMF) and isopropyl alcohol (IPA) in a volume ratio of 3:2.

[0018] S2. Selecting a multifunctional ligand containing a thiol group (-SH) with multi-point coordination ability; In order to ensure the stability and dynamics of multi-metal coordinated coordination, it is necessary to select thiol molecules with multi-site coordination ability. Such thiol molecules include but are not limited to: 2,3-dimercaptosuccinic acid (DMSA), 1,3-propanedithiol and polythiol polymers. The above thiol molecules have their own advantages. For example, 2,3-dimercaptosuccinic acid (DMSA) can provide strong adsorption and high dynamics; 1,3-propanedithiol is suitable for environmentally sensitive film passivation; polythiol polymers improve interface strength and ductility.

[0019] Preferably, the multifunctional ligand is present in the form of a solution having a thiol group (-SH) concentration of 0.05 M / L to 0.1 M / L.

[0020] The electrochemical activity of perovskites leads to the formation of halides (e.g. , ) or cations (such as ) migration, which is one of the important reasons for the aging and degradation of perovskites. The thiol group can adjust the local acidity and alkalinity through coordination, reduce the driving force of halide migration, and thus reduce the photoelectric performance attenuation caused by interface ion accumulation. The multi-metal coordinated coordination of the thiol group can form a stable ion barrier on the perovskite surface, and inhibit the degradation of the interface acidity and alkalinity by dynamically adjusting the interface. of loss.

[0021] In addition, the surface of perovskite crystals often has non-coordinating , halogen vacancy or Defects such as excess, which will increase non-radiative recombination channels and reduce the photoelectric conversion efficiency (PCE). Appropriate acid-base environment can improve the passivation effect. Thiol groups have higher activity under acidic conditions and can effectively coordinate non-coordinating , repairing interface defects. The neutral or weakly acidic environment produced by the synergistic effect of thiol groups and multi-metals can further enhance the passivation ability of thiol on interface defects and reduce interface energy level mismatch.

[0022] S3. Selecting salt substance 1 having metal ion 1 and salt substance 2 having metal ion 2, wherein metal ion 1 and metal ion 2 have complementary electronic structures; In this step, the metal ion 1 can be selected as or , correspondingly, the metal ion 2 is or Preferably, the substance salt 1 and the substance salt 2 are acetate or nitrate.

[0023] S4. According to the material ratio of thiol group (-SH), metal ion 1 and metal ion 2 having a molar mass ratio of 1:2:2, the multifunctional ligand, salt substance 1 and salt substance 2 are put into the polar solvent and uniformly mixed to form the interface modifier.

[0024] In order to uniformly mix the multifunctional ligand, salt substance 1 (or metal ion 1), and salt substance 2 (metal ion 2), after the multifunctional ligand, the salt substance 2 and the metal ion 2 are put into the polar solvent, they are fully stirred to form the interface modifier. For example, stirring is performed for 30 minutes.

[0025] Corresponding to the above preparation method, the present application also provides an interface modifier for a perovskite layer. The interface modifier is a multi-metal thiol coordinated coordination solution prepared based on the preparation method of the above perovskite layer interface modifier.

[0026] In addition, the present application also provides a method for preparing a perovskite film, comprising: preparing a perovskite layer at After annealing for a preset time, the polymetallic thiol coordinated coordination solution is spin-coated on the surface of the perovskite layer at a speed of 2000 rpm to form a uniformly covered thin film layer as an interface layer. - The heat treatment is performed within a certain range to promote the formation of the dynamic coordination network of the interface layer and enhance its adhesion.

[0027] The perovskite layer interface modifier obtained by the technical solution provided in this application has a self-repairing function and a dynamic regulation function on the surface of the perovskite layer by virtue of the mechanism that the weak coordination bonds between the thiol group and various metal ions can be broken and reorganized when stress or environmental changes occur. The interface modifier can regulate the acid-base environment on the surface of the perovskite under the synergistic effect of multiple metals, reduce the migration of halide ions in the perovskite layer, inhibit interface degradation, and improve the resistance of the perovskite layer to light aging.

[0028] For example, in one embodiment, after the interface modifier is spin-coated on the surface of the prepared perovskite layer to modify it to form an interface layer, the interface layer significantly reduces the defect state density between the perovskite layer and the ETL layer (reduced by about 30%-40%) through multi-metal-thiol coordination, thereby improving the interface carrier extraction efficiency and the photoelectric conversion efficiency (PCE) by more than 10%.

[0029] The dynamic passivation and reconstruction mechanism of the interface modifier effectively inhibits the migration of halide ions, reduces non-radiative recombination channels, and improves short-circuit current density (Jsc) and open-circuit voltage (Voc). After multiple stress tests (mechanical bending or temperature cycling), the interface cracks can be self-healed through the re-coordination of thiols and multi-metal ions, and the interface integrity retention rate is more than 98%.

[0030] At the same time, the perovskite component using the interface modifier in this embodiment has a photoelectric conversion efficiency retention rate of more than 92% after 1000 hours under high humidity and high temperature (85% RH, 85°C), which is significantly improved compared with the photoelectric conversion efficiency retention rate of the untreated device (50%-60%); after 200 hours of strong light irradiation (AM1.5, 1kW / m²), the perovskite layer does not show obvious yellowing, the photoelectric conversion efficiency decay is less than 5%, and the resistance to light degradation is good.

[0031] Finally, it should be noted that the above description is only a partial 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 substitution, 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 layer interface modifier, characterized in that: The preparation method comprises: adding a multifunctional ligand containing a thiol group (-SH) with multi-site coordination ability, a salt substance 1 having a metal ion 1, and a salt substance 2 having a metal ion 2 into a polar solvent according to a material ratio of thiol group (-SH), metal ion 1, and metal ion 2 of 1:2:2, and uniformly mixing them to obtain a multi-metal thiol synergistic coordination solution; the multi-metal thiol synergistic coordination solution is used as the interface modifier of the perovskite layer, and the metal ion 1 and the metal ion 2 have complementary electronic structures.

2. The preparation method according to claim 1, characterized in that The polar solvent includes at least one of N, N-dimethylformamide or isopropanol.

3. The preparation method according to claim 2, characterized in that: The polar solvent is prepared by using formamide (DMF) and isopropyl alcohol (IPA) in a volume ratio of 3:

2.

4. The preparation method according to claim 1, characterized in that: The multifunctional ligand exists in the form of a solution with a thiol group (-SH) concentration of 0.05M / L to 0.1M / L.

5. The preparation method according to claim 1, characterized in that: The metal ion 1 is or , metal ion 2 is or ; The substance salt 1 and the substance salt 2 are acetate or nitrate.

6. The preparation method according to claim 5, characterized in that: The multifunctional ligand includes at least one of 2,3-dimercaptosuccinic acid (DMSA), 1,3-propanedithiol and polythiol polymer.

7. The preparation method according to any one of claims 1 to 6, characterized in that The preparation method further comprises: after putting the multifunctional ligand, the metal ion 1 and the salt substance 2 into the polar solvent, stirring the mixture sufficiently to uniformly mix the metal ion 1, the metal ion 2 and the multifunctional ligand.

8. An interface modifier for a perovskite layer, characterized in that The interface modifier is a multi-metal thiol coordinated coordination solution prepared by the preparation method of the perovskite layer interface modifier according to any one of claims 1 to 7.

9. A method for preparing a perovskite film, characterized in that: The method comprises: spin coating the interface modifier according to claim 8 on the surface of the prepared perovskite layer at a rotation speed of 2000 rpm to form a uniformly covered thin film layer as an interface layer; then, - The heat treatment is performed within a certain range to promote the formation of the dynamic coordination network of the interface layer and enhance its adhesion.

10. The method according to claim 9, characterized in that The method further comprises: Before spin coating the interface modifier, the prepared perovskite layer is Annealing preset time.

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