Multifunctional High-Temperature Phase-Transition Energy Storage Material with Coexistence of Electrical–Thermal Double Switches:[(C<sub>6</sub>H<sub>15</sub>BrNO)<sub>2</sub>MBr<sub>4</sub>] (M = Cd and Zn)
Yukong Li, Ding‐Chong Han, Ting‐Ting Ying, Yun‐Zhi Tang, Yu‐Hui Tan, Wen‐Juan Wei, Peng-kang Du, Hao Zhang
Abstract
Two novel semiconductor organic–inorganic hybrid perovskites [(C6H15BrNO)2MBr4] (M = Cd for 1 and Zn for 2) were successfully synthesized, which undergo a high-temperature reversible transition at Tc (Tc = 379 K for 1, 407 K for 2). Differential scanning calorimetry (DSC) curve test shows that there is a pair of reversible thermal abnormal peaks at 379/348 K for compound 1 during the heating/cooling process, and the thermal hysteresis loop is ∼31 K. For compound 2, there is a pair of reversible thermal anomaly peaks at 407/375 K, and the thermal hysteresis loop is ∼33 K, indicating that the phase transition to a first-order phase transition. The dielectric test further confirmed the phase transition. X-ray single-crystal diffraction analysis showed that the space groups of compounds 1 and 2 at 300 K belong to C2/c and P21/c, and the temperature-variable powder X-ray diffraction (PXRD) test proved that compounds 1 and 2 had reversible structural phase transition. In addition, both UV–vis diffuse reflectance spectroscopy and density functional theory (DFT) calculations have confirmed that both compounds 1 and 2 are direct band gaps, with values of 4.116 and 4.205 eV, respectively. The above results show that 1 and 2 have fast switchable dielectric properties and potential applications in semiconductor materials.