Low-pressure accessible gas-quenching for absolute methylammonium-free perovskite solar cells

Gas-quenching is a promising technique for the up-scalable fabrication of metal halide perovskite solar cells (PSCs). However, it has been challenging to produce high-quality gas-quenched perovskite films without the use of the methylammonium (MA) cation. By employing tetramethylene sulfoxide (TMSO) as a ligand in the precursor solution, high-quality FA0.9Cs0.1PbI3 perovskite films have been successfully obtained by gas-quenching. A study on the precursor solution and film-forming process revealed the effect of TMSO on the formation of large-grain films, as well as the critical role of gas-quenching in regulating the intermediate films. The absolute MA-free perovskite device exhibits superior stability over the PSCs obtained with the MACl additive. The fabricated MA- and Br-free PSCs show a power conversion efficiency of 21.3% without any passivation treatment. Moreover, gas-quenching with TMSO enables a wide gas pressure processing window and superior accessibility to low-pressure processing, demonstrating its promising potential in up-scaling manufacturing of high-efficiency MA-free PSCs.