Structural Phase Transition and Switchable Dielectric Properties of a Unique Two-Dimensional Organic–Inorganic Hybrid Perovskite Compound [C6H11NH2CH3]4Pb3I10

The two-dimensional (2D) organic–inorganic hybrid perovskites with structural phase transition have been widely concerned for its diverse physical attributes. In the present work, an organic–inorganic hybrid perovskite compound with a 2D layered structure, (N-methylcyclohexylaminium)4Pb3I10 (1), has been synthesized. Interestingly, the inorganic framework of 1 adopts a unique 2D layer, in which the distorted skeletons of face-sharing octahedra are linked by four I atoms on terminals. Specific heat and differential scanning calorimetry (DSC) tests disclose that 1 experiences an invertible phase transition at 254 K with a thermal hysteresis of ∼11 K. In particular, the disorder–order dynamics of organic moieties and the deformation of inorganic layers account for its switchable dielectric responses along with dielectric anisotropic properties around 254 K. Besides, 1 exhibits a semiconducting feature with an optical band gap Eg = 2.48 eV. The electronic structure calculations show that the inorganic framework contributes to the band gap of 1. It is believed that our work would spur the exploration of novel organic–inorganic hybrid materials with multifunctionalities.