Dielectric phase transition triggered by the order–disorder transformation of cyclopropylamine in a layered organic–inorganic halide perovskite

Abstract

Cyclic organic amines are emerging as excellent building blocks to assemble organic–inorganic hybrid phase transition materials due to their flexible cyclic structure. Herein, we used a three-membered ring organic amine, cyclopropylamine, assembling a layered organic–inorganic hybrid dielectric phase transition compound ([C₃H₅NH₃]₂[CdCl₄], CPA) that displays a remarkable switchable dielectric response induced by an order–disorder transformation of the organic moiety. More specifically, the dielectric constant of CPA can be tuned between high- and low-dielectric states at ∼273 K, which demonstrates its potential application in a switchable dielectric field. In addition, theoretical analysis of electronic band structures suggests that CPA exhibits a direct-band-gap with the value of 5.20 eV. This solid-state structural phase transition triggered by ordering of a three-membered ring organic amine is reported for the first time, and it highlights a new potential strategy to design switchable dielectric materials.