Crystal growth, phase transition, and nuclear magnetic resonance of organic-inorganic hybrid perovskite NH(CH)CdCl.

Understanding the physicochemical properties of organic-inorganic hybrid materials is essential to promote their applications. In this study, a single crystal of NH(CH)CdCl was grown, and it exhibited a monoclinic structure. Its phase transition temperatures were 460 and 470 K, and it showed sufficient thermal stability. The changes in the NMR chemical shifts of each atom in the crystal with increasing temperature were determined; the chemical shift of H of NH in the NH(CH) cation changed with temperature, which was correlated to the changes in the chemical shift of N in NH. The change in Cd chemical shifts indicate the change of six Cl atoms around Cd in CdCl. Therefore, the change in the coordination geometry of CdCl is attributed to the change in the N-H⋯Cl hydrogen bond between the NH(CH) cation and CdCl anion. In addition, the C activation energies obtained from the spin-lattice relaxation time values are smaller than those of the H values, suggesting that is free compared to H in the cation. We believe that this study furthers our fundamental understanding of organic-inorganic hybrid materials to promote their practical solar cell applications.