Preparation Of All-inorganic CsPbX₃ Perovskite Thin Films And Research On Its Solar Cells

All-inorganic perovskite thin films have high absorption coefficient,strong light absorption capacity,continuously adjustable energy band,long carrier diffusion distance,high charge mobility,and other excellent photoelectric properties,which has become a research focus in semiconductor materials.Especially in the field of thin-film solar cells,organic-inorganic hybrid perovskite solar cells have low stability because the organic cations in the components are greatly affected by moisture,oxygen,ultraviolet rays,and temperature in the air.The all-inorganic perovskite thin films have great development prospects in the direction of solar cells because of its super thermal stability.This paper focuses on the research of all-inorganic Cs Pb(I_1-xBr_x)₃ thin films,the preparation of all-inorganic Cs Pb(I_1-xBr_x)₃ thin films by vacuum co-evaporation method,discusses the factors that affect the performance of the film,and uses Cs Pb Br₃ thin film as the light-absorbing layer to prepare all-inorganic solar cells,the feasibility of preparing solar cell devices by full vacuum method was studied.The main contents of this paper are as follows:（1）Cs Pb(I_1-xBr_x)₃ films were prepared by vacuum co-evaporation,and by changing the ratio of halogen Br and I in the film,four kinds of all-inorganic perovskite films were prepared:Cs Pb Br₃,Cs Pb IBr₂,Cs Pb I₂Br and Cs Pb I₃.As a result,it was found that with the increase of the proportion of iodine in the bromine/iodine mixed halide perovskite film,the absorption peak and the photoluminescence peak were red-shifted.（2）The effects of substrate temperature,annealing temperature and annealing time on the properties of thin films were explored.The Cs Pb Br₃ thin film was prepared by vacuum co-evaporation method,and the crystallization of the thin film was optimized by changing the preparation conditions of the thin film to obtain the desired cubic crystal.The Cs Pb Br₃ film was characterized by photoluminescence（PL）,absorption and transmission,XRD,SEM and EDS.The results show that the substrate temperature,annealing temperature and annealing time all have effects on the luminescence,absorption,surface morphology and crystallization of the Cs Pb Br₃ thin film.When the Cs Pb Br₃ thin film was prepared by dual-source co-evaporation at a substrate temperature of 200℃and annealed at 500℃for 30s,the Cs Pb Br₃ thin film had the best performance.（3）Two flat-structure solar cells were prepared by using Cs Pb Br₃ film as the light absorption layer.Both the electron transport layer and the hole transport layer used inorganic semiconductor materials.The device preparation method adopts the full vacuum method of thermal evaporation or magnetron sputtering.Both devices with different structures have solar cell characteristics and have a certain photoelectric conversion efficiency.Figure 42,table 8,reference 102.