Role of antisolvent temperature and quaternary ammonium cation-based ionic liquid engineering in the performance of perovskite solar cells processed under air ambient conditions

Abstract

Perovskite solar cells are becoming one of the strong contenders for renewable energy generation sources. However, to make the technology available on the market and commercially successful, efficient and stable perovskite solar cells must be fabricated under ambient conditions. Herein, a combination of antisolvent and ionic liquid engineering is applied to produce efficient and stable perovskite solar cells under ambient conditions. Chlorobenzene antisolvent of low-temperature produces compact perovskite films and better interfacial contact. A quaternary ammonium cation-based ionic liquid, trimethylpropylammonium bis(trifluoromethanesulfonyl)imide [TMPA][TFSI], is applied at the TiO₂/perovskite interface to passivate the interfacial defects and improve the electron transfer efficiency. The combined effect of low-temperature chlorobenzene antisolvent (5 °C) and 0.01 M [TMPA][TFSI] resulted in a power conversion efficiency enhancement of over 16% as compared to pristine devices. Interestingly, the optimized devices showed high stability and retained above 90% efficiency after 1500 h of dark storage with a periodic measurement under ambient conditions.