Optical properties of lead-free perovskite Cs2InAg(BrxCl1-x)6 for solar cell applications: A DFT study

Organic-inorganic metal halide perovskites have emerged as promising materials for low-cost, highefficiency solar cells. Chemical compositional tuning along with different device structures for fabrication and interfacial engineering made the record PCE of perovskite solar-cells reaching 25.2%, which is close to that of single crystal silicon solar cells. We investigated the structural, electronic and optical properties of bromine (Br) doped Cs2InAgCl6 in the cubic phase for various doping percentages. The lattice constants were optimized using Birch Murnaghan fit and band gap were found to be increasing as the doping percentage of Br is increased. The theoretical calculations were performed using generalized gradient approximation exchange correlation for all calculations. The optical properties are studied by comparing the absorption coefficients. Contour plots of charge density shows that the nature of chemical bonding is ionic. Band structure plot along high symmetry points revealed a direct band. (C) 2019 Elsevier Ltd. All rights reserved.