Study of the electronic and opto-electronic properties of the perovskite KPbBr3 by DFT and TDDFT methods

Abstract

In this paper, we applied the two methods: DFT and TDDFT to study the structural, electronic and optical properties of the inorganic solar perovskite KPbBr3. To reach this goal, we performed the DFT method under the Quantum Espresso package. The total energy of the cubic perovskites KPbBr3 has been calculated as a function of the lattice parameter a (Å). The two calculation methods have been carried out under the approximations: GGA-PBE and GGA-PBESol. In addition, the total and partial density of states (DOS) and the band structure of the studied compounds have been illustrated and discussed for the two cases in the presence or in the absence of the spin orbit coupling (SOC) approximation. The density functional theory (DFT) and time-dependent density-functional theory (TDDFT) have been explored in order to elaborate the optical properties of the inorganic solar perovskite KPbBr3 for solar cell applications. The band gap energy value found when applying the GGA-PBESol method without SOC approximation, is greater than that one computed when taking into account the SOC correction. Moreover, the optical properties of the studied materials have been elaborated and discussed.