Performance Study Of All-Inorganic CsPbI_3-xBr_x Perovskite Solar Cells

Since the advent of perovskite solar cells in 2009,they have attracted the attention and research of many researchers,and the power conversion efficiency has also increased from3.8%at the beginning to 25.7%today.Compared with organic/organic-inorganic hybrid perovskite,inorganic perovskite Cs Pb I₃ has better thermal stability and light stability,and there is no volatility problem of organic components.However,the extreme sensitivity of Cs Pb I₃ to moisture leads to its poor humidity stability,which also limits the application and development of inorganic perovskites.Stored in a high-humidity air environment,it will rapidly transform from a black phase to a yellow phase,thereby losing its excellent photoelectric properties.In view of this,this thesis works from the following two aspects,aiming at improving its stability.（1）Improving the stability of inorganic perovskite by germanium（Ge）element doping.According to the tolerance factor formula of perovskite,the introduction of Ge element can effectively increase the value of the tolerance factor,thereby improving the stability of the inorganic perovskite structure.The strategy of Ge doping greatly improves the surface morphology of the perovskite film and can reduce the annealing temperature of the inorganic perovskite.Compared with the device of the control group,the efficiency of the device was increased to 16.251%after the Ge doping.Further analysis found that this strategy can reduce the harsh environmental requirements for the preparation of inorganic,enabling it to be prepared in a high-humidity environment.（2）Octyl ammonium iodide（OAI）was added to the precursor solution as an additive to improve the resistance of Cs Pb I₃ perovskite to moisture.Since the instability of Cs Pb I₃mainly comes from the poor resistance to water,and OAI has certain hydrophobicity,it is added as an additive to the Cs Pb I₃ perovskite film to enhance the resistance of the film to water,thereby improving stability.At the same time,the addition of OAI can effectively passivate the defects in the perovskite film,reduce energy loss,and thus effectively improve the photoelectric conversion efficiency.The device optimized by OAI achieved an efficiency of 16.97%,and the stability of the device was also significantly improved.