Solvate phases crystallizing from hybrid halide perovskite solutions: Chemical classification and structural relations

Solution crystallization techniques of hybrid lead halides for perovskite photovoltaics, while remaining the most common method for fabricating solar cells, are inevitably complicated by the formation of numerous intermediate solvates that predetermine the morphology and properties of the final perovskite light-harvesting layer. Here, for the first time, a chemical classification of known solvates is proposed based on a comprehensive analysis of their structural features and relationships with possible structural types.