Phosphonium-Based One-Dimensional Perovskite with Switchable Dielectric Behaviors and Phase Transitions.

The one-dimensional (1D) ABX-type perovskite [(CH)PCHF]CdClBr () has been obtained on the basis of the design of an organic-inorganic hybrid. Strikingly, it experiences sequential phase transitions at around 295 and 336 K, respectively. Given the noticeable steplike dielectric anomalies in the vicinity of 295 K, is identified as a promising dielectric-switchable material. According to the single-crystal structure analysis, the order-to-disorder transformation of the [(CH)PCHF] cation is the main reason for the phase transitions and the change of space group from the orthorhombic (No. 62) to the hexagonal 6/ (No. 176). This design of a perovskite structure will inspire more advances in the ever-growing field of switchable functional materials.