Combined experimental and density functional theory studies of an organic-inorganic hybrid perovskite

Single crystals of [C 6 H 5 -C 2 H 4 -NH 3 ] 2 ZnCl 4 were obtained by slow evaporation at room temperature. Single-Crystal X-Ray Diffraction (SCXRD), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA) and UV-Visible spectroscopy were used to characterize the crystal structure, and thermal and optical properties, respectively. At 293 K, PEA-ZnCl 4 crystallizes in a monoclinic unit-cell in the P 2 1 / c space group a = 7.449(2) Å, b = 24.670(3) Å, c = 11.187(2) Å and β = 91.762(5)°, V = 2054.8(2) Å 3 and Z = 4. The DSC and TGA analyses show respectively the presence of two first order reversible phase transitions and a sample thermal stability below 541 K. The optical study reveals that the compound undergoes a direct optical transition and an energy gap about of E g = 4.46 eV. In parallel, ab initio DFT calculations are performed to study the electronic band structure, to examine electronic density and to calculate the gap energy value. The calculated values are in good agreement with the experimental data. The 3D-gap density of PEA-ZnCl 4 .