Research On Preparation And Photoelectric Performance Of CsPbBr₃ Perovskite Solar Cells

In recent years,organic-inorganic hybrid perovskite solar cells(PSCs)have achieved excellent photoelectric conversion efficiency(PCE),reaching 25.7%.,but problems such as moisture/thermal stability and cost limit their further commercial application.Allinorganic perovskites have been widely reported due to their excellent thermal stability and good photoelectric properties,among which,CsPbBr3’s inherent stability and low preparation cost,the all-inorganic halide perovskite material has attracted much attention from researchers.However,due to the low solubility of CsBr,the difficulty of preparing perovskite films is greatly increased.In addition,CsPbBr3 has a wide band gap(>2.3 eV).and there is a significant energy level difference between the perovskite layer and the counter electrode in the solar cell structure.This energy mismatch could potentially lead to a decrease in the overall PCE of the solar cell.In view of the above problems,this paper optimizes the preparation process of CsPbBr3 film,systematically studies the growth mechanism of the film and the factors affecting the photoelectric performance of the device,strives to improve the preparation process,and finds hole transport materials with matching energy levels to further improve the photoelectric performance of the cell.The research findings can be summarized as follows:(1)Firstly,the morphology of CsPbBr3 film was altered by regulating the PbBr2 annealing temperature,the number of spin coating times of CsBr/methanol solution and environmental humidity,and the results showed that these process conditions had a significant impact on the quality of CsPbBr3 film,and its surface morphology had a great influence on the photoelectric performance of the device.Secondly,through studying the effcet of electrode materials on the performance of solar cells,carbon electrode was selected as a counter electrode material.Finally,a small amount of CsBr was added to the PbBr2 precursor solution to shorten the device preparation process.and the final CsPbBr3 perovskite film had holes compared with the conventional process,and the thickness was reduced compared with the conventional process,but the device efficiency was comparable to the conventional process.(2)Based on carbon-based CsPbBr3 all-inorganic perovskite solar cells,an inorganic hole transport layer CO3O4 was introduced to improve the energy level matching at the perovskite layer/carbon electrode interface.The Co3O4 inorganic hole transport layer was obtained by one-step solution spin coating technology.The results show that Co3O4 effectively promotes the extraction of holes and inhibits charge recombination at the interface of CsPbBr3/carbon electrode interface due to its suitable energy level matching with the perovskite absorbing layer and carbon electrode.The efficiency of the cell using the Co3O4 hole transport layer increased from 7.54%to 9.07%,while cell showed excellent long-term humidity stability.