Single-crystal growth, crystal structure, and molecular dynamics of organic-inorganic [NH3(CH2)2NH3]CuBr4

As part of obtaining excellent properties that can be used as lead-free hybrid solar cells, the crystal growth, crystal structure, phase transition temperature, and thermal properties for [NH3(CH2)(2)NH3]CuBr4 were discussed. The crystal structure at 300 K was determined to be monoclinic by single-crystal X-ray diffraction (XRD) analysis. The phase transition temperatures were determined to be 447 and 473 K, and the results were consistent with the powder XRD patterns. Thermogravimetric analysis revealed thermal stability up to similar to 460 K. The continuous changes in the 1H and C-13 chemical shifts and N-14 static resonance frequency with increasing temperature are related to variations in the local environment and coordination geometry. The significant differences in activation energies obtained from the H-1 and C-13 spin-lattice relaxation times (t1 rho) at low and high temperatures were discussed. The activation energy results suggested that the energy barrier at low temperatures was related to the reorientation of the NH3 and CH2 groups around the three-fold symmetry axis, and the energy barrier at high temperatures was related to the reorientation of the [NH3(CH2)(2)NH3] cation. These physical properties will be provide important insights or potential applications of this crystal.