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

Abstract

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 °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 °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.