Efficient Perovskite Solar Cells with Cesium Acetate-Modified\nTiO₂ Electron Transport Layer

Abstract

The\nphotovoltaic performance of perovskite solar cells (PSCs) is\nstill below the Shockley–Queisser limit due to the impact of\ndefects originated from the surface and the bulk of the perovskite.\nHence, it is particularly important to alleviate non-radiative losses\nin the solar cell by employing an interface modification strategy.\nWe implemented TiO₂/CsAC as an electron transport layer\nto achieve high-performance devices based on diethylammonium bromide\n(DABr)-doped MAPbI₃. The critical role of cesium acetate\n(CsAC) is designed to improve perovskite crystallization and achieve\na high-quality interfacial contact between TiO₂ and the\nperovskite layer. TiO₂/CsAC promotes the shift of Br ions\nto form the Br-rich region at the perovskite/HTL interface simultaneously,\nwhich can enhance the extraction of holes and block the diffusion\nof electrons. Attributing to the modification of CsAC to TiO₂, the performance of DABr-doped MAPbI₃ PSC is improved\nsignificantly.