Bright and Stable Dion-Jacobson Tin Bromide Perovskite Microcrystals Realized by Primary Alcohol Dopants

In this study, conventional saturation recrystallization process was found to produce a complex mixture instead of pure Dion-Jacobson (DJ)-phase ODASnBr(4) perovskite single crystals (ODA denotes protonated 1,8-octanediamine), which originated from the strong hydrogen bonding in diammonium cations and the interaction with polar hydrogen bromide solution, resulting in the formation of impurities. Thus, additional primary alcohols, including ethanol, 1-propanol, 1-butanol, and 1-pentanol, were introduced to treat that mixture with an attempt to remove undesired byproducts, while also resulting in the molecular doping and enhanced crystallinity of DJ perovskites. The formation of O-H center dot center dot center dot Br hydrogen bonds between [SnBr6](4-) octahedron slabs and alcohols promoted the lattice coordination of the perovskites and the removal of undesired surface-absorbed water and byproducts, thereby achieving ODASnBr4[alcohol] perovskite microcrystals with high photoluminescence quantum yield close to 90%. Their thermal stability and oxidation resistance were also significantly enhanced as a result of improved lattice crystallinity and surface capping by dopants. The strategy introduced here offers prospects for further development of lead-free DJ perovskite materials with strong emissions and reliable stabilities.