Highly absorptive and mechanically stable double perovskites Cs2SnI6 and Cs2SnKrI6

Abstract

Numerous double perovskites have demonstrated their astonishing potential in several optoelectronic and optical communication areas. Cs2SnI6 has also attracted attention because of its unique vacancy-ordered structure. However, Cs2SnI6 fitted them as good absorbing material still we have attempted to dope Kr atom at the vacancy site to intensify absorption. Herein, we have enumerated the structural, electronic, optical, mechanical and thermoelectric properties of Cs2SnI6 and Cs2SnKrI6. All these physical properties have been computed using density functional theory based Wien2K simulation code. Cs2SnKrI6 exhibits the indirect band gap of ∼ 1.36 eV and direct band gap of ∼ 1.37 eV. Cs2SnI6 and Cs2SnKrI6 both are optically active in visible and near-infrared regions with high absorption. The optical conductivity and power factor are also increased to a substantial level after doping. We have studied the elastic properties to examine the mechanical stability of these materials. We have found B/G ratio of 2.64 and 2.07 for Cs2SnI6 and Cs2SnKrI6 respectively, which demonstrates the ductile nature. After getting these constructive results, we have concluded that power conversion efficiency will also stimulate up to a great extent by doping.