Method for preparing perovskite thin film in perovskite solar cell via solution air extraction and ventilation method

Abstract

The invention provides a method for preparing a perovskite thin film in a perovskite solar cell via a solution air extraction and ventilation method. The method comprises the following steps: a perovskite liquid film coated on a surface of a base body is subjected to air extracting and drying operation in an environment where the partial pressure of the solvent is lower than 99% saturated vapor pressure of the solvent at current temperature; during drying processes or after the perovskite liquid film is completely dries, a gas which does not react chemically with a perovskite is let in, and therefore a process that the solvent is evaporated or solvent molecules leave the environment can be accelerated via solvent molecule concentration dilution. Heterogeneous nucleation and growth of the surface of the base body can be realized via control over drying process conditions, and therefore a uniform and compact perovskite thin film can be formed. The method can be used for accelerating liquid film drying processes, making solvent steam molecules leave a surface of the thin film quickly, and obtaining the uniform-structured and compact perovskite thin film; thus current leakage caused by perovskite thin film loopholes can be prevented and the method can help make high-efficiency solar cells; the method is advantaged by simple operation, easy-to-implement property, low cost, high repetition accuracy, convenience for industrialization and the like.

Description

technical field [0001] The invention belongs to the fields of material science technology, film preparation technology and solar cell preparation technology, and in particular relates to a method for preparing a perovskite film in a perovskite solar cell by using a solution pumping and ventilating method. Background technique [0002] In the field of photovoltaics, organic-metal halides with a perovskite structure, as a light-absorbing material, have attracted great attention in the photovoltaic industry due to their unique properties. The conversion efficiency of perovskite solar cells has increased by leaps and bounds in recent years, surpassing 20%. As the basic material for photoelectric conversion in perovskite solar cells, perovskite thin films are the key and core of perovskite solar cells. The preparation process mainly adopts solution method, including one-step method and two-step method. Although the one-step method is relatively simple to operate, there are some ...

AI Technical Summary

Problems solved by technology

Although the one-step method is relatively simple to operate, there are some problems in the prepared perovskite film: the uniformity and crystallinity of the film cannot be effectively controlled, the grains of the perovskite film are coarse and dendritic, and the coverage of the substrate is low, resulting in Electrons are extremely easy to recombine with holes during transport, resulting in poor performance and insufficient stability of perovskite solar cells

The existing technical solutions are mainly through the natural drying of the solvent in the solution or direct heating and drying, it is difficult to achieve good control of the crystallization characteristics of the perovskite film, so a one-step method cannot obtain a uniform and dense perovskite film

It has been reported that speeding up the evaporation by air blowing can increase the drying speed of the solution to a certain extent, but the air blowing will easily cause the solution surface to be unstable, which will cause uneven surface fluctuations of the perovskite film, which may cause the substrate to be exposed and affect the perovskite solar cell. Uniformity and photoelectric performance, difficult to industrial application

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