Highly efficient and stable perovskite solar cells induced by novel bulk organosulfur ammonium

The additives can improve the crystallization and formation, passivate defects, stabilize the phase state, and adjust the interfacial structure and energy level of perovskite film in perovskite solar cells. Most additives are single functional additives and bifunctional additives. Only a few investigations have been reported about the multifunctional additives. In this work, a novel bulk organosulfur ammonium has been synthesized and utilized as multifunctional additive in perovskite solar cells. Due to the specific structure, the dithiooxamide iodide (DTAI2) additive could improve the crystallization of perovskite film, reduce the trap state density, and prevent the ionic migrating, resulting in the improved power conversion efficiency. The mechanism of the enhanced efficiency has been systematically discussed based on the photophysical properties.