First-principles calculations to investigate structural, electronic and optical properties of ternary copper halides AlCumXn (A = K, Rb, Cs; X = Cl, Br, I)

Abstract

Low-dimensional ternary metal halides have recently attracted much attention due to their excellent photoelectric performance is of significant interests. Considering the remarkable photoelectric properties of some copper - based halides, herein, we investigate the structural, electronic and optical properties of 3D, 1D and 0D structured ternary copper halides, including ACuX3, ACu2X3, A2CuX3, A4CuX6, and A3Cu2X5 using the first-principles. Their binding energies (Eb) and formation energies (Ef) were calculated, which confirmed the thermodynamic stability of these compounds. Most of these halides are direct band gap semiconductors. The valence band tops of these five type materials are mainly provided by Cu-d orbitals and halide X-p orbitals, while the conduction band bottoms are mainly provided by Cu-s and X-p orbitals. In addition,these ternary copper halides show significant light absorption characteristics, especially in the visible light range. Our results show AlCumXn (A = K, Rb, Cs; X = Cl, Br, I) would have wide photoelectric application potential.