Tuning Optoelectronic Properties of KBaTeBiO₆ Double Perovskite Through Cationic Interplay

Double-oxide perovskite materials are establishing a major part in optoelectronic industries. Recently, increased research on replacing lead (Pb) with other nontoxic, efficient cations in the perovskite structure has shown bismuth (Bi) and antimony (Sb) to be potential candidates. Structurally replacing Bi with Sb, in the present work, proves its compatible nature within the system. First-principles electronic structure calculations within the framework of density functional theory formalism have been employed in order to envisage the structural, electronic, and optical properties in one such lead-free double perovskite oxide, KBaTeBiO6. The analysis shows that the considered systems are thermodynamically and crystallographically stable. Further studies on electronic and optical properties reveal that the Sb-substituted systems show a better absorption nature with bandgap tuning. We have also thoroughly investigated the spectroscopic limited maximum efficiency, while we stress upon the issue of the spin–orbit coupling effect on the optoelectronic properties in this perovskite family. This work validates Sb as a potential candidate in replacing Bi with enhanced properties, leading to obtain better materials for optoelectronic applications