WO2024031752A1

WO2024031752A1 - Perovskite thin film, seed crystal-assisted film forming method, and perovskite solar cell

Info

Publication number: WO2024031752A1
Application number: PCT/CN2022/115219
Authority: WO
Inventors: 徐保民; 刘畅; 王行柱; 李亚茹; 陈石; 章勇; 周贤勇; 王登
Original assignee: 南方科技大学
Priority date: 2022-08-11
Filing date: 2022-08-26
Publication date: 2024-02-15
Also published as: CN115394927A

Abstract

The present application relates to the technical field of solar cells, and in particular to a perovskite thin film, a seed crystal-assisted film forming method, and a perovskite solar cell. A first aspect of the present application provides a perovskite thin film, comprising a base and a perovskite thin film layer bonded to the surface of the base, wherein the perovskite thin film layer is formed on the base by a mixed solution containing all-inorganic perovskite quantum dots and a perovskite precursor solution. Under the synergistic effect of the all-inorganic perovskite quantum dots and the perovskite precursor solution, the defects of the perovskite thin film can be overcome. The perovskite thin film layer of the present application has the prospects of being applied to other fields of photoelectric information functional materials, such as photoelectric detectors, LED light-emitting devices, and field effect transistors. In the film forming process of the mixed solution of the perovskite precursor solution, the all-inorganic perovskite quantum dots serve as seed crystals, and can induce the crystallization and rapid film forming of the mixed solution, thereby solving the problem that the forming of perovskite thin films is difficult and is low in efficiency.

Description

Perovskite thin films, seed-assisted film formation methods, perovskite solar cells

This application claims priority to the Chinese patent application with application number 202210962616.1 filed with the China Patent Office on August 11, 2022, the entire content of which is incorporated into this application by reference.

Technical field

The present application belongs to the technical field of solar cells, and in particular relates to a perovskite film, a seed-assisted film-forming method, and a perovskite solar cell.

Background technique

Compared with traditional crystalline silicon and inorganic thin film solar cells, perovskite solar cells have been widely studied due to their simple preparation process and low cost. In 2009, Miyasaka's research group first reported the preparation of a CH ₃ NH ₃ PbI ₃ perovskite solar cell with a photoelectric conversion efficiency of 3.8% and an open circuit voltage of 0.96 V, which launched the research on perovskite solar cells. Park and Gratzel et al. prepared a CH ₃ NH ₃ PbI ₃ all-solid-state battery device in 2012, with a photoelectric conversion efficiency of 9.7%. Since then, research on perovskite solar cells has been rapidly carried out at home and abroad: in 2015, Jeon and others increased the conversion efficiency to 20%; by 2018, Jaemin Lee's research group used substances such as dibenzophenone as the hole transport layer , the conversion efficiency reaches 23.3%; the recently updated "Battery Laboratory Maximum Efficiency" chart by the National Renewable Energy Laboratory (NREL, National Renewable Energy Laboratory) shows that the single-cell calcium battery developed by the Korea Institute of Chemical Technology and MIT The efficiency of titanium solar cells has reached a new high, reaching 25.7%, surpassing existing commercial solar cells such as polycrystalline silicon and copper indium gallium selenide thin films. Moreover, the stability of perovskite solar cells has also been significantly improved, and technology marketization is becoming a research hotspot in this field.

However, perovskite solar cells need to overcome two major issues to achieve ultimate commercialization, namely stability and film formation preparation process. Traditional preparation methods lack effective control over the perovskite film formation process, resulting in the formation of many defects, such as MA or FA vacancy defects, zero-valent Pb defects, Pb-I anti-site defects, etc. Therefore, high-quality films cannot be obtained with high reproducibility, and the stability of the device is poor.

technical problem

In view of the existing technology, the purpose of this application is to provide a perovskite film, a seed-assisted film formation method, and a perovskite solar cell, aiming to solve the problem of poor stability of existing perovskite films and traditional perovskite The film preparation method lacks effective control over the perovskite film formation process, which leads to the problem of many defects in the prepared perovskite film.

Technical solutions

In order to achieve the above application purpose, the technical solutions adopted in this application are as follows:

The first aspect of this application provides a perovskite film, including a perovskite film layer combined with a substrate and a surface of the substrate. The perovskite film layer is composed of a solution containing fully inorganic perovskite quantum dots and a perovskite precursor solution. A mixed solution is formed on the substrate.

The perovskite film provided in this application is formed on a substrate from a mixed solution containing all-inorganic perovskite quantum dots and a perovskite precursor solution. Under the synergistic effect of all-inorganic perovskite quantum dots and perovskite precursor solutions, the defects of perovskite films can be improved. Compared with existing films, it can improve MA or FA vacancy defects, zero-valent Pb defects, and Pb-I anti-site defects. If the perovskite film can be used to prepare electronic devices, it can improve the stability of electronic devices. Therefore, the perovskite thin film layer of the embodiment of the present application has the prospect of being used in other fields of optoelectronic information functional materials, such as photodetectors, LED light-emitting devices, field effect transistors, etc. In addition, during the film formation process of the mixed solution of perovskite precursor solution, all-inorganic perovskite quantum dots are used as crystal seeds to induce crystallization and rapid film formation, thus solving the difficulty and efficiency bias in perovskite film formation. low question.

The second aspect of this application provides a seed-assisted film formation method, including the following steps:

The mixed solution of all-inorganic perovskite quantum dots and perovskite precursor solution is treated with anti-solvent on the substrate to form a perovskite wet film;

The perovskite wet film is annealed to obtain a perovskite film.

The seed-assisted film formation method provided by the embodiments of the present application. The mixed solution of all-inorganic perovskite quantum dots and perovskite precursor solution is treated with an anti-solvent on the substrate to form a perovskite wet film to form a perovskite film. Annealing the perovskite wet film can form a perovskite film, in which the all-inorganic perovskite quantum dots have a stable structure and a uniform and adjustable size. The all-inorganic perovskite quantum dots serve as growth sites for perovskite grains. It can regulate the crystallization kinetics of perovskite film growth, improve the difficulty of film formation, low efficiency and poor stability of organic-inorganic hybrid perovskites, thereby improving the stability of perovskite films and optoelectronics. performance.

The third aspect of this application provides a perovskite solar cell, including a light absorption layer, the light absorption layer is the perovskite film mentioned above.

In this application, all-inorganic perovskite quantum dots are used as seed-assisted growth of high-quality perovskite films in perovskite solar cells, which can improve the photoelectric performance and service life of solar cells.

Description of drawings

Figure 1 is a structural diagram of a perovskite solar cell provided by an embodiment of the present application;

Figure 2 is a structural diagram of another perovskite solar cell provided by an embodiment of the present application.

Embodiments of the invention

In order to make the technical problems, technical solutions and beneficial effects to be solved by this application clearer, this application will be further described in detail below in conjunction with examples. It should be understood that the specific embodiments described here are only used to explain the present application and are not used to limit the present application.

In this application, the term "and/or" describes the relationship between related objects, indicating that there can be three relationships. For example, A and/or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. Condition. Where A and B can be singular or plural. The character "/" generally indicates that the related objects are in an "or" relationship.

In this application, "at least one" refers to one or more, and "plurality" refers to two or more. “At least one of the following” or similar expressions refers to any combination of these items, including any combination of single items (items) or plural items (items). For example, "at least one of a, b, or c", or "at least one of a, b, and c" can mean: a, b, c, a-b ( That is, a and b), a-c, b-c, or a-b-c, where a, b, and c can be single or multiple respectively.

It should be understood that in various embodiments of the present application, the size of the sequence numbers of the above-mentioned processes does not mean the order of execution. Some or all steps can be executed in parallel or one after another. The execution order of each process should be based on its function and order. The internal logic is determined and should not constitute any limitation on the implementation process of the implementation regulations of this application.

The terminology used in the embodiments of this application is only for the purpose of describing specific implementation regulations and is not intended to limit this application. As used in this specification and the appended claims, the singular forms "a," "the" and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise.

The weights of relevant components mentioned in the description of the embodiments of the present application may not only refer to the specific content of each component, but also represent the proportional relationship of weight between the components. Therefore, as long as the relevant components are combined according to the description of the embodiments of the present application, Any scaling up or down of the content is within the scope disclosed in the examples of this application. Specifically, the mass described in the description of the embodiments of this application may be mass units well-known in the chemical industry such as µg, mg, g, kg, etc.

The terms first and “second” are used for descriptive purposes only and are used to distinguish objects such as substances from each other, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of indicated technical features. For example, without departing from the scope of the implementation regulations of this application, the first XX may also be called the second XX, and similarly, the second XX may also be called the first XX. Therefore, features defined as "first" and "second" may explicitly or implicitly include one or more of these features.

The first aspect of the embodiment of the present application provides a perovskite film, including a perovskite film layer combined with a substrate and a surface of the substrate. The perovskite film layer is composed of a solution containing fully inorganic perovskite quantum dots and a perovskite precursor. A mixed solution is formed on the substrate.

The perovskite film provided in the embodiment of the present application is formed on a substrate from a mixed solution containing all-inorganic perovskite quantum dots and a perovskite precursor solution. Firstly, under the synergistic effect of all-inorganic perovskite quantum dots and perovskite precursor solution, the defects of the perovskite film can be improved. Compared with the existing films, the perovskite film provided in the embodiments of the present application can By improving MA or FA vacancy defects, 0-valent Pb defects, and Pb-I anti-position defects, if the perovskite films of the embodiments of the present application are used to prepare electronic devices, the stability of the electronic devices can be improved. Therefore, the perovskite films of the embodiments of the present application have potential applications in other fields of optoelectronic information functional materials, such as photodetectors, LED light-emitting devices, and field-effect transistors. Secondly, during the film formation process of the mixed solution of perovskite precursor solution, all-inorganic perovskite quantum dots are used as crystal seeds to induce crystallization and rapid film formation, thereby solving the difficulty of film formation of perovskite films. The problem of low efficiency.

In some embodiments, the perovskite precursor solution includes a hybrid perovskite material of ABY ₁ Y ₂ Y ₃ , wherein A is at least one of formamidine cations and methylamine cations, and B is lead ions, At least one of the tin ions, Y ₁ , Y ₂ , and Y ₃ , is each independently selected from any one of iodide ions, bromide ions, and chloride ions, has good photoelectric conversion rate, and can reduce production costs.

In some embodiments _, the structural _formula _of _the all- _inorganic perovskite quantum dots is CsPbX ₁ The composition is adjustable, among which the composition of all-inorganic perovskite quantum dots is adjustable. _The ABY ₁ Y ₂ Y ₃ hybrid perovskite material in the above article synergizes with _the CsPbX ₁ , 0-valent Pb defects, the effect of Pb-I anti-site defects, improve the stability and photoelectric performance of perovskite films.

In some embodiments, based on the mass percentage of the perovskite precursor solution being 100%, the mass percentage concentration of the all-inorganic perovskite quantum dots is 0.1~1%. The thickness of the perovskite film in the above article is 0.5~1 micron, which is moderate. The particle size of the crystal grains contained in the perovskite film layer is 0.5~1 micron, and the crystal grains are uniform. The roughness of the perovskite film layer is less than 20nm and the flatness is high.

The second aspect of the embodiments of the present application provides a seed-assisted film formation method, which includes the following steps:

Step S10: The mixed solution of all-inorganic perovskite quantum dots and perovskite precursor solution is treated with an anti-solvent on the substrate to form a perovskite wet film;

Step S20: anneal the perovskite wet film to obtain a perovskite film.

The seed-assisted film formation method provided in the embodiments of the present application mainly includes two steps. In the first step, the mixed solution of all-inorganic perovskite quantum dots and perovskite precursor solution is treated with anti-solvent on the substrate to form a perovskite wet film to form a perovskite film. The third step is to anneal the perovskite wet film to form a perovskite film. Among them, the all-inorganic perovskite quantum dots have a stable structure and a uniform and adjustable size. The all-inorganic perovskite quantum dots serve as perovskites. The growth site of the crystal grains can regulate the crystallization kinetics of perovskite film growth, improve the defects of difficulty in film formation, low efficiency and poor stability of organic-inorganic hybrid perovskite, thereby improving the performance of perovskite films. stability and photoelectric performance.

In some embodiments, before the above-mentioned step S10, a process of recording the all-inorganic perovskite quantum dots and the perovskite precursor solution is also included.

In some embodiments, the concentration of the perovskite precursor solution is 1.4~1.8 mol/L to facilitate subsequent film formation processing. In the above article, the solvent of the perovskite precursor solution includes at least one of N,N-dimethylformamide, dimethyl sulfoxide, gamma-martin lactone, and N-methylpyrrolidone, which can make all-inorganic calcium Titanium quantum dots and hybrid perovskite materials of ABY ₁ Y ₂ Y ₃ are highly dispersed in solvents.

In some embodiments, all-inorganic perovskite quantum dots are prepared by a method including the following steps:

_The first lead _source and _the cesium source are mixed _, and a combination reaction is performed to obtain _a first solution containing CsPbX ₁ Any of the chloride ions, the preparation method of all-inorganic perovskite quantum dots provided in the embodiments of the present application has high repeatability, can enrich the structure of CsPbX ₁ X ₂ X ₃ quantum dots, has a stable structure, and has uniform size.

In some embodiments, the material mass ratio of the first lead source and the cesium source is 0.5~1:1. The temperature of the compound reaction is 180~250℃. Specifically, the reaction temperature can be 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, or 250°C, but is not limited thereto.

In some embodiments, the particle size _of _the CsPbX ₁ Specifically, _the particle size _of CsPbX ₁

In some embodiments, the Pb source includes at least one of lead iodide, lead acetate, lead thiocyanide, lead bromide, and lead chloride, and the Cs source includes cesium acetate, cesium iodide, cesium bromide, and cesium chloride. , at least one of cesium carbonate. In some embodiments, the precursor solution uses lead iodide (PbI ₂ ), lead bromide (PbBr ₂ ), and lead chloride (PbCl ₂ ) as lead sources, and methylamine hydroiodide (MAI) and Formazan hydroiodide (FAI) is used as the A-site cation source, and by adjusting the proportions of different components, precursor solutions of perovskite materials with different band gaps can be obtained.

In some embodiments, the Pb source is lead iodide, the Cs source is cesium iodide, and the all-inorganic perovskite quantum dots include the following preparation steps:

Step S30: Perform a third mixing process on lead iodide and the cesium iodide to obtain a second solution containing _CsPbI3 quantum dots;

Step S40: Perform a fourth mixing process on the second lead source and the ligand in octadecene to obtain a third solution;

Step S50: Perform a fifth mixing process on the second solution and the dispersion to obtain a fourth solution;

Step S60: Perform a sixth mixing process on the third solution and the fourth solution, and perform a substitution reaction to obtain a fifth solution containing CsPbX ₁ X ₂ X ₃ quantum dots.

The all-inorganic perovskite quantum dots provided in the embodiments of this application are synthesized using a hot injection method, which mainly includes four steps. In the first step, lead iodide (PbI ₂ ) is used as the Pb source and cesium carbonate (Cs ₂ CO ₃ ) is used as the Cs source. The two are mixed with each other at high temperature to react to produce uniform size, nano-square morphology, Highly stable cubic phase CsPbI ₃ quantum dots. In the second step, lead bromide (PbBr ₂ ) and lead chloride (PbCl ₂ ) are added to the ligands and dissolved in octadecene at high temperature. In the third step, the CsPbI ₃ perovskite quantum dots and dispersion liquid are mixed to obtain a fourth solution containing highly dispersed CsPbI ₃ perovskite quantum dots to facilitate the subsequent replacement reaction. The fourth step is to mix the third solution and the fourth solution and perform anion exchange to obtain CsPbX ₁ X ₂ X ₃ quantum dots with different anion components. The embodiments _of _the present application provide CsPbX ₁

In some embodiments, the ligand includes at least one of oleic acid or oleylamine, the second lead source includes at least one of lead bromide and lead chloride, and the dispersion includes toluene, chlorobenzene, n-octane, tetrafluoroethylene, At least one kind of carbon chloride is used, and the temperature of the second mixing treatment is 180~250°C. Further, the mass ratio of lead iodide and cesium iodide is 0.5~1:1, the mass ratio of the second lead source and ligand is 1~5:1, and the mass ratio of the first solution and dispersion is 0.1~0.5: 1. The mass ratio of the first solution and the second solution is 0.01~0.5:1.

In some embodiments, in the above step S10, forming a perovskite wet film by anti-solvent treatment on the substrate from a mixed solution of all-inorganic perovskite quantum dots and perovskite precursor solution specifically includes the following steps:

The mixed solution of all-inorganic perovskite quantum dots and perovskite precursor solution is treated with anti-solvent on the substrate to form a perovskite wet film. The perovskite wet film is spin-coated on the substrate, and it is necessary to spin-coat at the same time. By adding an antisolvent, a perovskite film can be obtained.

In some embodiments, the spin coating conditions are 3000 to 5000 revolutions for 30 to 60 seconds, and the mass ratio of the antisolvent to the dispersion is 1 to 10:1. The antisolvent in the above article includes at least one of chlorobenzene, diethyl ether or toluene, so that a high-quality organic-inorganic hybrid perovskite layer can be prepared using a one-step antisolvent film formation method.

The third aspect of the embodiments of the present application provides a perovskite solar cell, including a light absorption layer, and the light absorption layer is the perovskite film mentioned above.

In the embodiments of this application, all-inorganic perovskite quantum dots are used as seed-assisted growth of high-quality perovskite films in perovskite solar cells, which can improve the photoelectric performance and service life of solar cells.

In some embodiments, according to a reasonable battery device structure, a conductive substrate, a hole transport layer, an electron transport layer and a metal electrode are combined to form a complete solar cell device. While achieving a photoelectric conversion efficiency of more than 24%, the battery has a long-term and stable service life, which can provide a technical foundation for future commercial development. Specifically, the structure of the perovskite solar cell is: glass substrate/anode (ITO)/hole transport layer (PTAA)/perovskite light absorption layer/electron transport layer (C60)/interface modification layer (BCP)/cathode (Ag) ).

In some embodiments, please refer to the conductive substrate shown in FIG. 1 , wherein indium tin oxide (ITO) may be deposited on the conductive substrate. In addition, the method of treating the glass substrate deposited with ITO is: perform continuous multi-step ultrasonic cleaning on the glass substrate. In each ultrasonic cleaning tank, add detergent, deionized water, acetone, and ethanol in sequence; dry the substrate after ultrasonic cleaning. ; Before use, the ITO glass substrate needs to be irradiated with UV light.

In some embodiments, please refer to Figure 1, the hole transport layer is stacked on the surface of the glass substrate, wherein the hole transport layer is made of poly[bis(4-phenyl)(2,4,6-tri Methylphenylamine] (PTAA) material is formed. In addition, the preparation method of the PTAA hole transport layer is as follows: Dissolve PTAA powder in chlorobenzene at a concentration of 2 mg/mL. After being fully dissolved, apply it on the ITO substrate under spin coating conditions at 5000 rpm for 30 seconds, and then Anneal under hot stage at 100°C for 10 minutes.

In some embodiments, as shown in FIG. 1 , the perovskite film is stacked on the surface of the hole transport layer.

In some embodiments, please refer to FIG. 1 , the electron transport layer is stacked on the surface of the hole transport layer, wherein the electron transport layer is formed of a material containing fullerene (C60), and the interface modification layer is formed of a material containing dimethyl Materials based on 4,7-diphenyl-1,10-phenanthroline (BCP). In addition, the preparation method of the C60 electron transport layer and the BCP interface modification layer is to deposit the C60 layer and the BCP layer at one time through thermal evaporation under the condition of vacuum degree <10 ^-5 Pa, with thicknesses of 30 nanometers and 6 nanometers respectively.

In some embodiments, please refer to FIG. 1 . Metal electrodes are stacked on the surface of the electron transport layer, where the metal electrodes are formed of materials containing Cu or Ag. In addition, the metal electrode is prepared by thermal evaporation deposition under a vacuum of <10-5 Pa, with a thickness of 80 to 120 nanometers.

In order to make the above implementation details and operations of the present application clearly understood by those skilled in the art, and to significantly reflect the progressive performance of the perovskite films, seed-assisted film formation methods, and perovskite solar cells in the embodiments of the present application, the following is provided by Multiple embodiments are provided to illustrate the above technical solution.

Example 1

This embodiment provides a perovskite film, including a PTAA substrate and a perovskite film layer bonded to the surface of the PTAA substrate. The perovskite film layer is composed of CsPbI ₃ all-inorganic perovskite quantum dots and FAPbI ₃ perovskite. A mixed solution of precursor solutions was formed on the PTAA substrate, where the thickness of the perovskite film layer was 1 micron.

Example 2

This embodiment provides a method for preparing the perovskite film in Embodiment 1, which includes the following steps:

Step S01: Perform a third mixing process on lead iodide and cesium iodide at 180~250°C to obtain a second solution containing _CsPbI3 quantum dots.

Step S02: Weigh formamidine ammonium iodide (FAI), lead iodide (PbI ₂ ) and methylamine chloride (MACl) in a glove box at a molar ratio of 1:1:0.2 and dissolve them in DMF/DMSO ( In the mixed solution (volume ratio is 4/1), a FAPbI ₃ perovskite precursor solution with a concentration of 1.5~2.0 moles per liter is obtained.

Step S03: Mix the FAPbI ₃ perovskite precursor solution and the all-inorganic perovskite quantum dots CsPbI ₃ in a certain proportion (the amount of CsPbI ₃ material accounts for 1-5%) to obtain a fully inorganic perovskite quantum dot. Perovskite precursor solution of _CsPbI3 .

Step S04: Then drop the perovskite precursor solution on the PTAA substrate, supplemented by spin coating conditions of 3000-5000 rpm for 30-60 seconds, while adding 150 μl of chlorobenzene as an antisolvent, and the resulting perovskite thin film Wet film.

Step S05: anneal the perovskite thin wet film at 150°C for 30 minutes to finally obtain a perovskite thin wet film (thickness: 1 micron).

Example 3

This embodiment provides a perovskite solar cell with the following structure: glass substrate/anode (ITO)/hole transport layer (PTAA)/perovskite light absorption layer prepared in Example 2/electron transport layer (C60) /Interface modification layer (BCP)/Cathode (Ag).

Example 4

This embodiment provides a method for preparing the perovskite solar cell in Embodiment 1, which includes the following steps:

Step S04: Process the glass substrate deposited with ITO: perform continuous multi-step ultrasonic cleaning on the glass substrate. In each ultrasonic cleaning tank, add detergent, deionized water, acetone, and ethanol in sequence; dry the substrate after ultrasonic cleaning; use Before processing, the ITO glass substrate needs to be irradiated with UV light.

Step S05: Preparation of PTAA hole transport layer: Dissolve PTAA powder in chlorobenzene at a concentration of 2 mg/mL. After being fully dissolved, apply it on the ITO substrate under spin coating conditions of 5000 rpm for 30 seconds, and then Anneal under hot stage at 100°C for 10 minutes.

Step S06: The steps are the same as those in Embodiment 2 and will not be described again.

Step S07: Preparation of the C60 electron transport layer and the BCP interface modification layer: deposit the C60 layer and the BCP layer at one time by thermal evaporation under vacuum conditions <10-5 Pa, with thicknesses of 30 nanometers and 6 nanometers respectively.

Step S08: Preparation of metal electrode: The metal electrode is mainly Cu or Ag, which is deposited by thermal evaporation under the condition of vacuum degree <10-5 Pa, with a thickness of 80-120 nanometers.

Example 5

This embodiment provides a perovskite film, including a PTAA substrate and a perovskite film layer combined on the surface of the PTAA substrate. The perovskite film layer is composed of CsPbBr ₃ all-inorganic perovskite quantum dots and FAPbI ₃ perovskite. A mixed solution of precursor solutions was formed on the PTAA substrate, where the thickness of the perovskite film layer was 1 micron.

Example 6

This embodiment provides a method for preparing the perovskite film in Embodiment 5, which includes the following steps:

Step S01: Perform a third mixing process on lead bromide and cesium bromide at 180~250°C to obtain a second solution containing _CsPbBr3 quantum dots.

Step S02: Weigh formamidine ammonium iodide (FAI), lead iodide (PbI ₂ ) and methylamine chloride (MACl) in a glove box at a molar ratio of 1:1:0.2 and dissolve them in DMF/DMSO ( In the mixed solution (volume ratio is 4/1), a FAPbI ₃ perovskite precursor solution with a concentration of 1.5-2.0 moles per liter is obtained.

Step S03: Mix the FAPbI ₃ perovskite precursor solution and the all-inorganic perovskite quantum dots CsPbBr ₃ in a certain proportion (the amount of CsPbI ₃ material accounts for 1-5%) to obtain a fully inorganic perovskite quantum dot. Perovskite precursor solution of _CsPbBr3 .

Example 7

This embodiment provides a structure of a perovskite solar cell: glass substrate/anode (ITO)/hole transport layer (PTAA)/perovskite light absorption layer prepared in Example 5/electron transport layer (C60) /Interface modification layer (BCP)/cathode (Ag), its structure, please refer to Figure 2, which includes glass/ITO layer, PTAA layer is stacked on the surface of glass substrate/anode (ITO) layer, FAPbI ₃ /CsPbBr _{The 3} quantum dot layer is stacked on the surface of the PTAA layer, the C60/BCP layer is stacked on the surface of the FAPbI ₃ /CsPbBr ₃ quantum dot layer, and the Ag layer is stacked on the surface of the C60/BCP layer.

Example 8

Step S06: The steps are the same as those in Embodiment 6 and will not be described again.

Example 9

This embodiment provides a perovskite film, including a PTAA substrate and a perovskite film layer combined on the surface of the PTAA substrate. The perovskite film layer is composed of CsPbClBrI-containing all-inorganic perovskite quantum dots and FAPbI ₃ perovskite precursors. A mixed solution of the bulk solution was formed on the PTAA substrate, where the thickness of the perovskite film layer was 1 micron.

Example 10

This embodiment provides a method for preparing the perovskite film in Embodiment 9, which includes the following steps:

Step S02: Mix one or more of lead bromide PbBr ₂ and lead chloride PbCl ₂ and add the ligand oleic acid OA or oleylamine OLA to dissolve it in octadecene at high temperature.

Step S03: Inject the toluene dispersion of the synthesized CsPbI ₃ perovskite quantum dots into the above solution for anion exchange to obtain different anion components (the X component can be among Cl, Br, and I). One or more combinations can result in CsPbClBrI all-inorganic perovskite quantum dots (the energy band of the perovskite quantum dot can be adjusted).

Step S04: Weigh formamidine ammonium iodide (FAI), lead iodide (PbI ₂ ) and methylamine chloride (MACl) in a glove box at a molar ratio of 1:1:0.2 and dissolve them in DMF/DMSO ( In the mixed solution (volume ratio is 4/1), a FAPbI ₃ perovskite precursor solution with a concentration of 1.5-2.0 moles per liter is obtained.

Step S05: After mixing the FAPbI ₃ perovskite precursor solution and the all-inorganic perovskite quantum dots CsPbClBrI in a certain proportion (the amount of CsPbI ₃ material accounts for 1-5%), obtain the all-inorganic perovskite quantum dots CsPbI ₃ perovskite precursor solution.

Step S06: Then drop the perovskite precursor solution on the PTAA substrate, supplemented by spin coating conditions of 3000-5000 rpm for 30-60 seconds, while adding 150 μl of chlorobenzene as an antisolvent, and the resulting perovskite thin film Wet film.

Step S07: anneal the perovskite thin wet film at 150°C for 30 minutes to finally obtain a perovskite thin wet film (thickness: 1 micron).

Example 11

This embodiment provides a structure of a perovskite solar cell: glass substrate/anode (ITO)/hole transport layer (PTAA)/perovskite light absorption layer prepared in Example 10/electron transport layer (C60) /Interface modification layer (BCP)/Cathode (Ag).

Example 12

This embodiment provides a method for preparing the perovskite solar cell in Embodiment 10, which includes the following steps:

Step S08 processes the glass substrate deposited with ITO: perform continuous multi-step ultrasonic cleaning on the glass substrate. In each ultrasonic cleaning tank, add detergent, deionized water, acetone, and ethanol in sequence; dry the substrate after ultrasonic cleaning; before use , the ITO glass substrate needs to be irradiated with UV light.

Step S09, preparation of PTAA hole transport layer: Dissolve PTAA powder in chlorobenzene at a concentration of 2 mg/mL. After being fully dissolved, apply it on the ITO substrate under spin coating conditions of 5000 rpm for 30 seconds, and then Anneal under hot stage at 100°C for 10 minutes.

Step S10: The steps are the same as those in Embodiment 2 and will not be described again.

Step S11, preparation of the C60 electron transport layer and the BCP interface modification layer: deposit the C60 layer and the BCP layer at one time by thermal evaporation under the condition of vacuum degree <10-5 Pa, with thicknesses of 30 nanometers and 6 nanometers respectively.

Step S12, preparation of metal electrode: The metal electrode is mainly Cu or Ag, which is deposited by thermal evaporation under the condition of vacuum degree <10-5 Pa, with a thickness of 80-120 nanometers.

Comparative ratio

This comparative example provides a solar cell, including a glass substrate/anode (ITO)/hole transport layer (PTAA)/perovskite light absorption layer/electron transport layer (C60)/interface modification layer (BCP)/cathode (Ag ), wherein the perovskite light-absorbing layer includes a PTAA substrate and a perovskite thin film layer combined on the surface of the PTAA substrate. The perovskite thin film layer is formed on the PTAA substrate by a mixed solution of FAPbI ₃ perovskite precursor solution, where, The thickness of the perovskite film layer is 1 micron.

Optoelectronic performance testing of perovskite solar cells

100 milliwatts per square centimeter simulated light source in AM1.5G (Enlitech Solar Simulator SS-F5-3A), the current density-voltage (J-V) characteristic curve of the battery is tested; the measurement is performed under room temperature, air (40% humidity), and unpackaged conditions, using a computer-controlled Keithley 2400 source. The external quantum efficiency (EQE) was measured using a DSR100UV-B spectrometer with an SR830 lock-in amplifier at room temperature, air (40% humidity), and unpackaged conditions, and its light source was a bromine tungsten lamp.

The test results of the current density-voltage characteristic curves of the perovskite solar cells provided in Example 4, Example 8, Example 10 and Comparative Example 1 are as shown in Table 1 below.

Table 1

编号 serial number	开路电压（V） Open circuit voltage (V)	短路电流密度（mA/cm2） Short circuit current density (mA/cm2)	填充因子（%） Fill factor (%)	光电转换效率（%） Photoelectric conversion efficiency (%)
实施例4 Example 4	1.18 1.18	25.19 25.19	82.20 82.20	24.43 24.43
实施例8 Example 8	1.15 1.15	25.18 25.18	80.32 80.32	23.25 23.25
实施例12 Example 12	1.14 1.14	25.06 25.06	79.95 79.95	22.84 22.84
对比例 Comparative ratio	1.09 1.09	24.38 24.38	77.02 77.02	20.46 20.46

It can be seen from Table 1 that compared with other embodiments, the perovskite solar cell formed by CsPbI ₃ seed crystal assisted film formation has the most excellent photoelectric performance, with an open circuit voltage of 1.18V and a short circuit current density of 25.19mA/cm2. The device has a filling factor of 82.20%) and a photoelectric conversion efficiency of 24.43%. Compared with the device in the comparative example without perovskite quantum dot seed-assisted film formation, the efficiency is significantly improved.

Comparing the experimental results of Example 4, Example 8, and Example 12, Example 4 is the best experimental plan.

The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application shall be included in the protection of the present application. within the range.

Claims

A perovskite film, characterized in that it includes a perovskite film layer combined with a substrate and the surface of the substrate, and the perovskite film layer is composed of a solution containing fully inorganic perovskite quantum dots and a perovskite precursor. A mixed solution is formed on the substrate.
The perovskite film of claim 1, wherein the perovskite precursor solution includes a hybrid perovskite material of ABY 1 Y 2 Y 3 , wherein A is a formamidine cation or a methylamine cation. At least one of them, B is at least one of lead ions and tin ions, and Y 1 , Y 2 , and Y 3 are each independently selected from any one of iodide ions, bromide ions, and chloride ions;

Or / and, the structural formula of the all-inorganic perovskite quantum dots is CsPbX 1 kind;

Or/and, based on the mass percentage of the perovskite precursor solution being 100%, the mass percentage concentration of the all-inorganic perovskite quantum dots is 0.1~1%;

Or/and, the thickness of the perovskite film layer is 0.5~1 micron;

Or/and, the particle size of the crystal grains contained in the perovskite thin film layer is 0.5~1 micron;

Or/and, the roughness of the perovskite thin film layer is less than 20 nm.
A seed-assisted film-forming method, characterized in that it includes the following steps:

The mixed solution of all-inorganic perovskite quantum dots and perovskite precursor solution is treated with anti-solvent on the substrate to form a perovskite wet film;

The perovskite wet film is annealed to obtain a perovskite film.
The seed-assisted film formation method according to claim 3, wherein the concentration of the perovskite precursor solution is 1.4~1.8 mol/L;

Or/and, the solvent of the perovskite precursor solution includes at least one of N,N-dimethylformamide, dimethyl sulfoxide, gamma-martin lactone, and N-methylpyrrolidone.
The seed-assisted film formation method according to claim 3, wherein the all-inorganic perovskite quantum dots are prepared according to a method including the following steps:

The first lead source and the cesium source are subjected to a second mixing process, and a combination reaction is performed to obtain a first solution containing CsPbX 1 Any of ions and chloride ions.
The seed-assisted film forming method according to claim 5, wherein the material mass ratio of the first lead source and the cesium source is 0.5~1:1;

Or/and, the temperature of the compound reaction is 180~250℃;

Or/and, the crystal phase of the CsPbX 1 X 2 X 3 quantum dots is a cubic phase;

Or/and, the particle size of the CsPbX 1 X 2 X 3 quantum dots is 3~20nm;

Or/and, the first lead source includes at least one of lead iodide, lead acetate, lead thiocyanide, lead bromide, and lead chloride;

Or/and, the cesium source includes at least one of cesium acetate, cesium iodide, cesium bromide, cesium chloride, and cesium carbonate.
The seed-assisted film forming method of claim 6, wherein the first lead source is the lead iodide, the cesium source is the cesium iodide, and the all-inorganic perovskite quantum dots Including the following preparation steps:

Perform a third mixing process on the lead iodide and the cesium iodide to obtain a second solution containing CsPbI3 quantum dots;

Perform a fourth mixing process on the second lead source and the ligand in octadecene to obtain a third solution;

Perform a fifth mixing process on the second solution and the dispersion to obtain a fourth solution;

The third solution and the fourth solution are subjected to a sixth mixing process, and a substitution reaction is performed to obtain a fifth solution containing CsPbX 1 X 2 X 3 quantum dots.
The seed-assisted film-forming method of claim 7, wherein the ligand includes at least one of oleic acid or oleylamine;

Or/and, the second lead source includes at least one of lead bromide and lead chloride;

Or/and, the dispersion includes at least one of toluene, chlorobenzene, n-octane, and carbon tetrachloride;

Or/and, the mass ratio of the lead iodide and cesium iodide is 0.5~1:1;

Or/and, the mass ratio of the second lead source and ligand is 1~5:1;

Or/and, the mass ratio of the second solution and the dispersion is 0.1~0.5:1;

Or/and, the mass ratio of the fourth solution and the fifth solution is 0.01~0.5:1;

Or/and, the second lead source includes at least one of lead bromide and lead chloride.
A perovskite solar cell, characterized in that it includes a light absorption layer, and the light absorption layer includes the perovskite film of claim 1 or 2.
The perovskite solar cell of claim 9, further comprising an electronic functional layer stacked with the light absorbing layer, wherein the electronic functional layer includes a conductive substrate, a hole transport layer, and an electron transport layer. , at least one of metal electrodes.