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 ODASnBr₄ 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...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.