Reversible Phase Transition and Dielectric Response of Hybrid Lead-Free Antimony-Based Crystals

Organic–inorganic hybrid phase transition materials have garnered significant attention due to their adjustable structures, solution-processability, and outstanding properties. Among these materials, antimony (Sb)-based hybrids have notably been synthesized extensively, attributed to their reversible phase transitions, narrow band gaps, and ferroelectric characteristics. In this study, two Sb-based phase transition materials, (CPEA)3SbBr6 (CPEA-Br) and (FPEA)2SbBr5 (FPEA-Br) (where CPEA = 2-(2-chlorophenyl)ethylamine and FPEA = 4-fluorophenethylamine), were synthesized by modifying the organic cations. These materials exhibit a satisfactory dielectric stability and narrow band gaps, as well as higher phase transition temperatures compared to most reported homologues. Reversible dielectric states and semiconductor properties have been demonstrated, highlighting their potential for applications in photoelectric detection and temperature sensors.