Theoretical Study On The Optical Properties Of Perovskite Solar Cells

In this thesis,the first-principles theoretical study of perovskite solar cells is carried out.A scientific and effective solution to the toxicity and instability of the perovskite CH₃NH₃PbI₃ was proposed.Perovskite-derived compounds were also studied,and a method for converting the perovskite material from an indirect bandgap to a direct bandgap was studied.The main contents of this article are as follows:?1?The Pb element is replaced with Ge,and the electronic structures after replacement are calculated.The bandgap values,electronic properties and optical properties were systematically calculated.The results show that CH₃NH₃GeI₃ has a suitable direct band gap value,as well as excellent electronic properties,high carrier mobility and optical properties.?2?In order to study more deeply whether Ge element can effectively replace Pb element and get perovskite solar cell absorber layer material with good properties in this paper.CH₃NH₃GeCl₃ and CH₃NH₃GeBr₃ were obtained after the substitution of I element in CH₃NH₃GeI₃ perovskite.A systematic study comparing their related properties.?3?The electronic and optical properties of Cs₂BiAgCl₆ and Cs₂BiAgBr₆ double perovskite materials were calculated.Transforming it from indirect band gap to direct band gap by strains.The transformation process was studied by a large number of calculations to provide more theoretical support for more excellent perovskite solar cells.