Phase transition, thermal stability, and molecular dynamics of organic-inorganic hybrid perovskite NH3(CH2)6NH3CuCl4 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 [NH3(CH2)6NH3]CuCl4 crystal was conducted. The crystals had a monoclinic structure with space group P21/n and lattice constants a = 7.2224 Å, b = 7.6112 Å, c = 23.3315 Å, β = 91.930°, and Z = 4 at 300 K, and the phase transition temperature (T C) 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 1H chemical shifts in NH3 and the influence of C1 located close to NH3 in the [NH3(CH2)6NH3] cation near T C are determined to be large, which implies that the structural change of CuCl4 linked to N-H⋯Cl is large. The 1H spin-lattice relaxation time (T 1ρ) in NH3 is shorter than that of CH2, and the 13C T 1ρ values for C1 close to NH3 are shorter than those of C2 and C3 due to the influence of the paramagnetic Cu2+ ion in square planar geometry CuCl4. 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 CuCl4 anion.Organic-inorganic hybrid perovskites have various potential applications in fuel cells and solar cells. In this regard, the physicochemical properties of an organic-inorganic [NH3(CH2)6NH3]CuCl4 crystal was conducted. The crystals had a monoclinic structure with space group P21/n and lattice constants a = 7.2224 Å, b = 7.6112 Å, c = 23.3315 Å, β = 91.930°, and Z = 4 at 300 K, and the phase transition temperature (T C) 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 1H chemical shifts in NH3 and the influence of C1 located close to NH3 in the [NH3(CH2)6NH3] cation near T C are determined to be large, which implies that the structural change of CuCl4 linked to N-H⋯Cl is large. The 1H spin-lattice relaxation time (T 1ρ) in NH3 is shorter than that of CH2, and the 13C T 1ρ values for C1 close to NH3 are shorter than those of C2 and C3 due to the influence of the paramagnetic Cu2+ ion in square planar geometry CuCl4. 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 CuCl4 anion.