Improved perovskite crystallization by antisolvent engineering in tin-perovskite photovoltaics

Tin-based perovskites are considered the candidate with the most potential as lead-free perovskites because of their excellent optoelectronic properties. As a conventional precursor solvent for the fabrication of tin-based perovskite films, dimethyl sulfoxide (DMSO) can form intermediates with SnI₂, which slows down the crystal growth and thus induces a smooth surface. However, the DMSO solvent exhibits a high donor number and low vapor pressure, whereas the typical anti-solvent chlorobenzene displays a low donor number, resulting in a lack of solvent-cleaning ability and excess DMSO remaining in the perovskite film. Here, we used dimethyl sulfide as an anti-solvent to prepare tin-based perovskite film; it has a high donor number and high vapor pressure. It was found that the introduction of dimethyl sulfide greatly improved the morphology and quality of the perovskite films. In addition, the crystallinity of the thin film improves the transport of charge carriers and reduces defects, resulting in a champion device efficiency of 5.3%.