Preparation method and application of black blue perovskite thin film

Abstract

The invention belongs to the field of preparation of a thin film material, and particularly relates to preparation method and application of a black blue perovskite (FAPbI3) thin film. The method comprises the following steps of dissolving iodized formamidine (FAI) and lead iodide (PbI2) in a precursor solvent according to a certain stoichiometric ratio, and performing room-temperature stirring until complete dissolving is achieved, wherein the precursor solvent is a mixed solvent of Lewis base such as dimethylformamide (DMF) and N-methyl pyrrolidone (NMP); spin-coating the perovskite precursor solution on a substrate at a certain rotational speed, and dropwise adding reversed-polarity solvents such as diethyl ether, chlorobenzene and methylbenzene after a spin-coating machine reaches a designated rotational speed; and placing the substrate on a heating table after spin-coating is ended, and performing annealing for 2-60 minutes under 120-180 DEG C to prepare the black blue perovskitethin film. The black blue perovskite (FAPbI3) thin film prepared by the method is high in purity and low in delta phase content, and a perovskite layer employed on a perovskite solar cell can employ the black blue perovskite thin film prepared by the method.

Description

technical field [0001] The invention belongs to the field of film material preparation, specifically a blue-black perovskite (FAPbI 3 ) film preparation method and its application. Background technique [0002] Perovskite solar cells are based on halogen-containing organic-inorganic hybrid perovskite materials (MAPbI 3 , FAPbI 3 etc. MA:CH 3 NH 3 , FA: NH 2 CH=NH 2 ) as the core of new photovoltaic cells, this type of material has high molar extinction coefficient, wide absorption spectrum range, excellent carrier transport performance, low cost, simple preparation process, colorful and adjustable, and can be synthesized on flexible substrates, etc. Many advantages. After rapid development in recent years, the laboratory conversion efficiency of perovskite photovoltaic cells has exceeded 20%, and some performances have reached or even exceeded thin-film photovoltaic cells such as cadmium telluride and copper indium gallium selenide, which have excellent civilian prosp...

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Problems solved by technology

[0004] However, for FAPbI 3 Type perovskite materials, because this material is prone to non-perovskite delta phases at temperatures below 160 °C, and the generation of delta phases will seriously damage the performance of photovoltaic cells, which makes high-quality FAPbI 3 The control of delta phase content in the preparation of type perovskite thin films has become the focus of researchers and industry

For example: Chinese patent application (publication number CN105006522A), discloses a kind of perovskite-based inverted thin-film solar cell and its preparation method, FAPbI 3 The preparation steps of thin film are: (1) formamidine iodide (NH 2 CH=NH 2 I(FAI)) and lead iodide (PbI 2 ) was mixed and dissolved in dimethylformamide (DMF) solvent at a molar ratio of 1:1, and after stirring at room temperature, the solution was filtered; (2) spin-coating FAPbI on the substrate 3 The perovskite precursor layer is cleaned with chlorobenzene during the spin coating process; the conductive substrate is annealed to the perovskite precursor solution at 120-140°C, and FAPbI can be prepared after the perovskite layer is completely crystallized 3 type perovskite film, but the delta phase content in the film prepared by this method is usually large, which inhibits the further improvement of battery performance

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