Thiosemicarbazide-complexed SnO2 electron transport layers for high-efficiency MAPbI3 perovskite solar cells

High-quality electron transport layers (ETLs) are a crucial component of high-performance perovskite solar cells (PSCs) with the n–i–p configuration. Herein, a facile and effective way to improve the properties of SnO2 ETLs is developed via introducing thiosemicarbazide (TSC) as a multifunctional additive. Due to the interaction between TSC and SnO2 nanocrystals, the oxygen vacancies in SnO2 could be effectively passivated, increasing the conductivity of SnO2 ETLs. Moreover, the morphology of SnO2 ETLs is improved and the wettability is also increased with TSC introduction, facilitating crystallization of perovskite films. Consequently, the PSCs based on TSC-complexed SnO2 ETLs achieved a significant increase of power conversion efficiency with much reduced hysteresis and increased stability.