Thermal, ferroelastic, and structural properties near phase transitions of organic-inorganic perovskite type [NH 3 (CH 2 ) 3 NH 3 ]CdBr 4 crystals.

Hybrid perovskites have potential applications in several electrochemical devices such as supercapacitors, batteries, and fuel cells. Therefore, we studied the thermal behavior and structural dynamics of organic-inorganic hybrid perovskite [(NH 3 )(CH 2 ) 3 (NH 3 )]CdBr 4 crystals near phase transition temperatures, T C2 (=328 K) and T C1 (=363 K), which are correlated to the structural dynamics of cations and anions. The structural geometry and molecular dynamics with emphasis on the role of the [(NH 3 )(CH 2 ) 3 (NH 3 )] cation and CdBr 6 anion were discussed in terms of MAS 1 H NMR, MAS 13 C NMR, 14 N NMR, and 113 Cd NMR as a function of the temperature. The environments surrounding 1 H, 13 C, 14 N, and 113 Cd are investigated near T C1 and T C2 using these results. Spin-lattice relaxation times T 1ρ were discussed in terms of the change in temperature. The discontinuous changes of 1 H T 1ρ and 13 C T 1ρ near T C1 are consistent with the change of the lattice constant. Shorter T 1ρ values at high temperature indicate that 1 H and 13 C in the organic chains are more flexible at these temperatures. Based on these results, the physicochemical properties of the cation and anion during the III-II-I phase transitions were discussed. This study was conducted to improve the relatively weak thermal stability compared to the high efficiency for a variety of applications.