Integrated large-area perovskite thin film annealing process

Abstract

The invention provides an integrated large-area perovskite thin film annealing process, and aims to prepare a high-quality perovskite thin film. The method specifically comprises the following steps: firstly, preparing a perovskite liquid film from a perovskite layer precursor solution through a liquid phase method; then, the liquid film is moved to a heating table to be subjected to pre-annealing treatment; and then, transferring the pre-annealed film to an air fryer or a fixed-temperature dry air steam cabinet, and carrying out heating treatment by using gas with temperature. According to the process, the annealing time of the perovskite thin film is effectively shortened, the requirement on the flatness of the solar cell substrate glass is reduced, the problems caused by thermal deformation of a large-area metal heating stage are reduced, the defect state density of the thin film is reduced, and the passivation effect is enhanced. The film is subjected to heat transfer annealing from six directions by introducing gas with temperature, so that the production yield of the large-area perovskite film and the overall quality of the film are remarkably improved. Compared with the traditional hot stage annealing process, the method has the advantages of higher compatibility to the glass substrate, short annealing time, high yield and the like.

Description

Technical Field

[0001] The present invention relates to thin film preparation technology and solar cell preparation technology, and in particular to an integrated large-area perovskite thin film annealing process. Background Art

[0002] In recent years, organic-inorganic hybrid perovskite materials have attracted much attention from researchers due to their advantages such as high light absorption coefficient, adjustable band gap, and long carrier diffusion length. The conversion efficiency of perovskite solar cells based on perovskite films has increased by leaps and bounds in recent years, reaching 26.7%. The quality of perovskite films directly affects the performance parameters of solar cells.

[0003] Recently, the present inventors reported the application of vapor phase method to achieve perovskite thin film annealing.

[0004] Based on this, the inventors have developed an integrated large-area perovskite film annealing process, that is, using a vapor medium as the heat source for annealing the perovskite film, which can not only meet the humidity annealing in the two-step annealing process, but also meet the vapor phase passivation of large-area films. Through vapor phase medium annealing, a shorter annealing time is achieved, and high-quality perovskite films with low defect state density are obtained. Summary of the invention

[0005] The purpose of the present invention is to provide an integrated large-area perovskite film annealing process, which anneals the perovskite film by introducing a gas phase environment with dual controllable temperature and humidity, replacing the traditional hot stage annealing. This process can not only accurately control the humidity, but also simultaneously introduce gas phase passivation treatment during the large-area film annealing process, thereby realizing the integrated treatment of annealing and passivation. The passivation gas can select a gaseous or gasifiable passivator, including halogen compounds, etc. These passivation gases can be flexibly selected according to the properties of the film, and during the annealing process, they are combined with the active sites on the surface of the film to effectively reduce the defect state density. At the same time, the gas phase passivation process of the present invention is carried out under the condition of no electric field, ensuring the efficiency and stability of the whole process. Through the simultaneous annealing and passivation, the present invention significantly improves the quality and performance of the perovskite film, especially in the uniformity, stability and optoelectronic properties of large-area films. It has outstanding advantages and provides a scalable solution for industrial production. To achieve the above purpose, the specific technical scheme adopted by the present invention is as follows:

[0006] An integrated large-area perovskite film annealing process, the method comprising the following steps:

[0007] (1) preparing a perovskite precursor solution to prepare a perovskite liquid film;

[0008] (2) (2) placing the liquid film in step (1) on a hot stage for pre-annealing;

[0009] (3) The film in step (2) is transferred to a gas phase dielectric annealing device to anneal the perovskite film, and the annealing process of the perovskite film is monitored by an in-situ analysis system.

[0010] The present application can stably control the humidity in the annealing environment by adding a certain proportion of water vapor into the dry gas at a specific temperature, thereby achieving precise and controllable humidity annealing to obtain high-quality perovskite films.

[0011] According to the present invention, in the step (1), after the perovskite precursor solution is prepared, the perovskite liquid film is prepared by a one-step spin coating method or a two-step spin coating method.

[0012] According to the present invention, in step (1), the thin film is an organic-inorganic hybrid perovskite liquid film and an all-inorganic perovskite liquid film.

[0013] According to the present invention, the specific steps of step (2) are: moving the prepared liquid film to a heating medium, with a pre-annealing temperature of 90° C.-120° C. and a pre-annealing time of 1-3 min.

[0014] According to the present invention, the specific gas phase annealing device in step (3) is an air fryer or a fixed temperature dry air steam cabinet.

[0015] According to the present invention, the specific steps of step (3) are: transferring the pre-annealed film to an air fryer or a fixed temperature dry air steam cabinet, and annealing it at a temperature of 100° C.-150° C. for 10-30 minutes.

[0016] According to the present invention, the pre-annealed film in step (3) cannot be directly exposed to high-speed hot air flow, and needs to be covered with gauze or temperature-resistant films with different pore sizes.

[0017] According to the present invention, the in-situ analysis system of step (3) is an in-situ ultraviolet-visible light absorption characterization system.

[0018] Beneficial effects of the present invention: The advantages of the present invention are that, compared with hot stage annealing, the gas phase medium annealing time is shorter, the compatibility with the flatness of the perovskite film substrate is higher, it is more suitable for the preparation of large-area perovskite films, and the humidity during the annealing process can be accurately controlled. The integrated annealing and passivation treatment of the perovskite film is achieved by introducing gas phase passivation molecules. Compared with liquid phase medium annealing, gas phase medium annealing is more environmentally friendly, has a high safety factor, and is lower in cost. The present invention realizes different types of annealing processes for perovskite films, has strong scalability, is low in price and more environmentally friendly, and can obtain high-quality large-area perovskite films. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1It is a schematic diagram of a device for an integrated large-area perovskite film annealing process of the present invention;

[0020] Figure 2 This is an in-situ absorption diagram of the two-dimensional perovskite film prepared by the integrated method in Example 1 of the present invention under different humidity conditions. DETAILED DESCRIPTION

[0021] The method of the present invention will be described in further detail below in conjunction with specific embodiments. The following embodiments are only for exemplary purposes to illustrate and explain the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0022] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0023] Example 1

[0024] In this embodiment, the prepared perovskite film is placed in different humidity environments to observe the changes in its absorption. The in-situ UV-visible light analyzer is used to monitor the changes in the absorption of the film in real time. Figure 1 The specific steps are as follows:

[0025] (1) PEABr (40.4 mg) and PbBr2 (36.7 mg) were dissolved in 1 mL DMSO and CsBr (59.6 mg), PbBr2 (73.4 mg), and EABr (15.1 mg) were dissolved in DMSO (2 mL). After the two bottles of solution were completely dissolved, they were mixed. The perovskite solution was spin-coated on the substrate in a glove box using a spin coater (3000 rpm, 120 s). At the 39th second, toluene anti-solvent was added.

[0026] (2) The substrate coated with the perovskite liquid film is taken out from the protective atmosphere of the glove box and placed in environments with different humidity.

[0027] (3) While step (2) is being performed, an in-situ spectrometer is used to monitor the absorption changes of the two-dimensional thin perovskite film in situ. The results are as follows: Figure 2 shown.

[0028] Example 2

[0029] (1) CsI, FAI, MAI, and PbI2 were mixed in 1 ml of DMF:DMSO (4:1 / v:v) mixed solvent to prepare a perovskite solution (1.5 M) with the chemical formula of FA 0.85 MA 0.1 Cs 0.05PbI3, an excess of 10 mol% PbI2 is required to improve device performance. Then 12.5 mol% MACl is added to the perovskite precursor solution and stirred for 2 h. 50 μL of the perovskite solution is spin-coated on the FTO / NiO x The spin coating was continued for 10 s at 1000 rpm and then for 40 s at 5000 rpm. 15 s before the end of the spin coating, 200 μL of CB was dropped on the center of the film.

[0030] (2) The substrate coated with the perovskite liquid film is placed on a hot plate at a temperature of 90°C-120°C for pre-annealing for 1-3 minutes.

[0031] (3) Place the pre-annealed film in a vapor phase annealing device (such as Figure 1 ), annealing is performed at a temperature of 100°C-150°C, and the annealing time is 10-30 minutes.

[0032] The above contents are merely examples and explanations of the structure of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. An integrated large-area perovskite film annealing process, characterized in that: The method comprises the following steps: (1) preparing a perovskite precursor solution to prepare a perovskite liquid film; (2) placing the liquid film in step (1) on a hot stage for short-term pre-annealing; (3) The pre-annealed film is transferred to a gas phase annealing device and annealed using a temperature- and humidity-controlled gas. The annealing process of the perovskite film is monitored in real time using an in-situ analysis system.

2. The integrated large-area perovskite thin film annealing process according to claim 1, characterized in that: In the step (1), after the perovskite precursor solution is prepared, the perovskite liquid film is prepared by a multi-layer spin coating method, combined with precise humidity control to ensure the quality and uniformity of each layer of the film. In the step (1), after the perovskite precursor solution is prepared, the perovskite liquid film is prepared by a one-step spin coating method or a two-step spin coating method.

3. The integrated large-area perovskite thin film annealing process according to claim 1, characterized in that: The perovskite liquid film can be an organic-inorganic hybrid perovskite, an all-inorganic perovskite or a composite film thereof, and is suitable for a variety of substrates, including flexible substrates.

4. The integrated large-area perovskite thin film annealing process according to claim 1, characterized in that: The specific steps of step (2) are: moving the prepared liquid film to a heating medium, with a pre-annealing temperature of 90° C.-120° C. and a pre-annealing time of 1-3 minutes.

5. The integrated large-area perovskite thin film annealing process according to claim 1, characterized in that: The specific gas phase annealing device in step (3) is an air fryer or a fixed temperature dry air steam cabinet.

6. The integrated large-area perovskite thin film annealing process according to claim 1, characterized in that: The specific steps of step (3) are: transferring the pre-annealed film to an air fryer or a fixed temperature dry air steam cabinet, and annealing it at a temperature of 100° C.-150° C. for 10-30 minutes.

7. The integrated large-area perovskite thin film annealing process according to claim 1, characterized in that: The pre-annealed film in step (3) cannot be directly exposed to high-speed hot air flow, and needs to be covered with gauze or temperature-resistant films of different pore sizes.

8. The integrated large-area perovskite thin film annealing process according to claim 1, characterized in that: The in-situ analysis system of step (3) is an in-situ ultraviolet-visible light absorption characterization system.

9. An integrated large-area perovskite film annealing process, characterized in that: By using steps (1)-(3) as described in any one of claims 1-8, when the test result shows that the absorption test of the perovskite film obtained by the gas phase dielectric annealing method is higher than the absorption of the perovskite film obtained by the hot stage annealing method, it can be determined that the method of the present invention improves the quality of the film.

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