Enantiomeric perovskite with a dual phase transition at high temperature

Temperature-dependent physical switching materials have been of wide concern for materials chemists. Among them, switchable dielectric perovskite materials have shown huge application potential in the fields of sensing, information storage, and electronics. In particular, for better practical application, obtaining dual-phase-change switching materials with a high phase transition temperature (Tc) is still a worthwhile issue to study. In this work, we synthesized chiral hybrid organic inorganic perovskites, namely, (R)-, (S)- and (rac)-N,N-dimethyl-3-fluoropyrrolidinium (DMFP) CdCl3. The enantiomeric compound undergoes a dual phase transition with a Tc of 460 K and 367 K. Tc significantly increased by 28 K from 411 K of (N,N-dimethyl pyrrolidinium) (DMP) CdCl3 to 439 K of (rac)-DMFP CdCl3. Besides, (R) and (S)-DMFP CdCl3 are the first example of chiral perovskites that show dual Tc with robust switching dielectric characteristics. This work could be a pathway for designing multifunctional chiral perovskite-type switchable materials.