Ab initio study of K[formula omitted]Cu[formula omitted]P[formula omitted] material for photovoltaic applications

Abstract

Search for efficient materials for application in the fields of optoelectronics and photovoltaics are some of the most active areas of research across the world. The potential of compounds such as K3Cu3P2 is not yet fully realized. The ab initio studies based on density functional theory (DFT) to investigate the structural, electronic, elastic, and optical properties of K3Cu3P2 have been performed. Ground state properties have been computed in three different scenarios, i.e: with spin–orbit coupling (SOC), without spin–orbit coupling, and with the Hubbard U parameter. Direct electronic bandgaps of 1.338 eV, 1.323 eV, and 1.673 eV has been obtained for K3Cu3P2 without SOC, K3Cu3P2 with SOC and K3Cu3P2 with Hubbard U, respectively. In all the cases, Cu-d orbitals have been observed to be dominant at the top of the valence band. The effect of SOC on the K3Cu3P2 computed lattice constant, and bandgap has been found to be insignificant. The mechanical stability test revealed that K3Cu3P2 is mechanically stable at zero pressure. The optical band gap has been found to increase by 0.635 eV when Hubbard U is taken into consideration. Generally, the inclusion of the Hubbard U parameter in density functional theory improves the predictions of the bandgap and optical properties.