Phase transition, thermal stability, and molecular dynamics of organic-inorganic hybrid perovskite [NH 3 (CH 2 ) 6 NH 3 ]CuCl 4 crystals

Organic-inorganic hybrid perovskites have various potential applications in fuel cells and solar cells. In this regard, the physicochemical properties of an organic-inorganic [NH (CH ) NH ]CuCl crystal was conducted. The crystals had a monoclinic structure with space group 2 / and lattice constants = 7.2224 Å, = 7.6112 Å, = 23.3315 Å, = 91.930°, and = 4 at 300 K, and the phase transition temperature ( ) was determined to be 363 K by X-ray diffraction and differential scanning calorimetry experiments. From the nuclear magnetic resonance experimental results, the changes in the H chemical shifts in NH and the influence of C1 located close to NH in the [NH (CH ) NH ] cation near are determined to be large, which implies that the structural change of CuCl linked to N-H⋯Cl is large. The H spin-lattice relaxation time ( ) in NH is shorter than that of CH , and the C values for C1 close to NH are shorter than those of C2 and C3 due to the influence of the paramagnetic Cu ion in square planar geometry CuCl . The structural mechanism for the phase transition was the change in the N-H⋯Cl hydrogen bond and was associated with the structural dynamics of the CuCl anion.