Efficient planar mixed-cation perovskite photovoltaics with low-temperature-processed indium sulfide as electron transport material

Abstract

Electron transport materials(ETMs) are crucial for efficient transport of photocarriers from the perovskites to the cathode in perovskite solar cells (PSCs). Although titanium dioxide (TiO2) is frequently employed as an ETM, PSC performance and applicability are hindered by its high-temperature manufacturing and limited electron mobility. In this work, a low-temperature solution-processable indium sulfide (In2S3) was incorporated into triple-cation perovskite solar cells to be an efficient ETM for the first time. After solvent-thermal synthesis of In2S3, followed by spin-coatingpreparation of In2S3 ETM, aPSC is constructed. The photoelectrical measurements show that the In2S3-based PSC has lower density of charge traps, higher conductivity, better electron transportation at the In2S3/perovskite interfaces, and a lower transfer resistance and carrier recombination. The PSC-based In2S3 yields a champion efficiency of 18.182%, and the PSC-based TiO2 gets an efficiency of 15.288%. Without encapsulation, the In2S3-based devices demonstrate increased stability in ambient environments. Our ETM layer and perovskite were made at low temperatures, which may open up new possibilities for solution-processed flexible electronics.