High-temperature giant dielectric switching in an organic–inorganic hybrid material

Abstract

With the increasing research on giant dielectric materials, there is growing interest in the development of switching materials with giant dielectric properties. In this study, a novel organic–inorganic hybrid material (Et₃NC₂H₄Br)FeCl₄ was synthesized. It was characterized through differential scanning calorimetry (DSC) and in situ temperature-dependent powder X-ray diffraction (PXRD), which determined its phase transition temperature (T_C) to be 362 K. Temperature-dependent dielectric measurements revealed that the material exhibited switchable dielectric properties, with the real part of the dielectric constant exceeding 10⁶ at 500 Hz and a dielectric switching ratio surpassing 10³. The ratio refers to the ratio between the high dielectric state and the low dielectric state of a step-like dielectric anomaly. Single-crystal X-ray diffraction (SCXRD) analysis confirmed that the material crystallized in the P2₁/c space group with a zero-dimensional structure. The optical bandgap, determined through UV-visible spectroscopy, was calculated to be 2.62 eV. Additionally, analysis using Hirshfeld surfaces and 2D fingerprint plots revealed that the predominant intermolecular interactions are H⋯Cl and H⋯H interactions. This study is anticipated to provide insights and hope for the design and application of high-temperature giant dielectric switching materials.