Double-Side Interface Engineering Synergistically Boosts the Efficiency of Inorganic CsPbIBr_2 Perovskite Solar Cells Over 12

摘要

All-inorganic CsPbIBr_2 perovskite solar cells (PSCs) have aroused theworldwide interest because of their excellent thermal stability. However,the bottom and upper surfaces of CsPbIBr_2 films are vulnerable to surfacedefects, corroding the carrier dynamic in PSCs. Meanwhile, the bandalignment mismatch also affects the interfacial carrier transport. Therefore,this work systematically investigates the passivation effect and band alignmentof rubidium acetate (RbAc) interface layer at electron transport layer(ETL)/perovskite and perovskite/hole transport layer (HTL), respectively.When RbAc is introduced to ETL/perovskite interface, the improved morphologyquality of CsPbIBr_2 films and the elevated conductive band minimumof SnO_2 leads to effective electron extraction and band alignment. Furthermore,once RbAc is introduced to perovskite/HTL interface, it passivatesgrain boundary defects and reduces the roughness of CsPbIBr_2 films, contributingto reduced nonradiative recombination. In addition, the raised valenceband maximum of CsPbIBr_2 also accelerates the hole transfer. It is found thateach single-side interface modification contributes to improved photovoltaicperformance and air stability. Consequently, a synergy effect of double-sideinterface modification is investigated for improving the device efficiency.Accordingly, the modified PSCs achieve a champion efficiency of 12.11%,which is increased by 30.78% compared to that of the pristine devices.