Substrate-Independent and Antisolvent-Free Fabrication Method for Tin Perovskite Films via Imidazole-Complexed Intermediates

Abstract

The fabrication of metal halide perovskite thin films, particularly those containing Sn, relies heavily on the use of antisolvents. Film quality is strongly influenced by factors such as the choice of antisolvent, the primary precursor solvent, perovskite composition, and the size and wettability of the substrates. This complexity makes process optimization challenging and impedes the development of efficient tin perovskite solar cells (PSCs). In this work, we present a vacuum-quenching with crystal growth regulator (V-CGR) method, an antisolvent- and dimethyl sulfoxide (DMSO)-free, vacuum-assisted fabrication process for tin perovskite films whereby crystal growth could be regulated through the formation of intermediate films containing an amorphous [SnI₂–(1-vinylimidazole)] complex. The V-CGR method is compatible with diverse perovskite compositions and substrates, enabling the formation of uniform tin perovskite films up to 7.5 × 7.5 cm² and allowing device fabrication on hydrophobic hole-transporting monolayers such as MeO-2PACz and 2PACz.