Adjusting the Crystallization of Tin Perovskites through Thiophene Additives for Improved Photovoltaic Stability.

Tin-based perovskites (Sn-PVK) are promising lead-free alternatives for efficient photovoltaic technology, but they face challenges related to bulk and surface defects due to suboptimal crystallization and Sn oxidation. Introducing thiophene-2-ethylammonium halides (TEAX, where X = I, Br, Cl) improves FASnI crystallization and reduces Sn formation. This is achieved by adjusting the crystallization dynamics through the formation of a complex between S and Sn during the preparation of the precursor solution, which also inhibits Sn oxidation in the resulting films.