Ethyl acetate green antisolvent process for high-performance planar low-temperature SnO2-based perovskite solar cells made in ambient air

One-step antisolvent deposition has been considered as one of the most feasible methods to obtain high-performance perovskite solar cells (PSCs). However, most of the reported high-performance PSCs are based on the toxic anti-solvents, which is a major issue for the potential commercialization of PSCs. SnO2 has been successfully used as an efficient electron transport layer (ETL) material in PSCs, but the preparation of low-temperature processed crystallization SnO2 ETLs is still a challenge. In this work, ethyl acetate (EA) as a green antisolvent is introduced into the perovskite crystallization process, resulting in uniform and compact perovskite films with large grain size, reduced grain boundaries, and low defect density. Low-temperature (100 degrees C) processed SnO2 ETL provides good interface contact between ETL and perovskite layer, facilitating photoelectron extraction and transport. As a result, a champion power conversion efficiency (PCE) of 17.83% has been achieved. More importantly, unencapsulated PSC retains 84.80% of its original PCE value after storage in atmosphere for 80 days (> 1900 h). Apart from great air stability, the final devices also show excellent thermal (100 degrees C) stability. It is particularly noteworthy that all the preparation and measurement processes were performed under ambient conditions. These findings present a green path towards manufacturing efficient and stable air-processed PSCs.