Chlorine-Modified Sno2 Electron Transport Layer For High-Efficiency Perovskite Solar Cells

A high-quality electron transport layer (ETL) is a critical component for the realization of high-efficiency perovskite solar cells. We developed a controllable direct-contact reaction process to prepare a chlorinated SnO2 (SnO2-Cl) ETL. It is unique in that (a) 12-dichlorobenzene is used to provide more reactive Cl radicals for more in-depth passivation; (b) it does not introduce any impurities other than chlorine. It is found that the chlorine modification significantly improves the electron extraction. Consequently, its associated solar cell efficiency is increased from 17.01% to 17.81% comparing to the pristine SnO2 ETL without the modification. The hysteresis index is significantly reduced to 0.017 for the SnO2-Cl ETL. image