Preparation, Thermal, and Physical Properties of Perovskite-Type (C₃H₇NH₃)₂CdCl₄ Crystals

Abstract

To investigate the thermal and physical properties of perovskite-type (C3H7NH3)2CdCl4, its temperature-dependent chemical shifts and spin⁻lattice relaxation times are measured using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), magic angle spinning nuclear magnetic resonance (MAS NMR), and static NMR methods. Above 300 K, two phase transitions are observed at 398 K and 538 K. Each proton and carbon in the (C3H7NH3) cation is distinguished in the MAS NMR results. The environments around 1H, 13C, and 14N do not change with temperature according to the NMR spectra. In contrast, the resonance frequency of 113Cd in the CdCl6 octahedra decreases with increasing temperature, indicating an environmental change. The uniaxial rotations for 1H and 13C have high mobility at both high and low temperatures, and these are related to the phase transitions. In addition, the molecular motion of 113Cd in the anion becomes activated upon raising the temperature.

Keywords

• perovskite
• (C₃H₇NH₃)₂CdCl₄
• NMR
• phase transition