Designing indirect–direct bandgap transitions in double perovskites

Abstract

A general design strategy is presented for tuning the convergence of direct and indirect bandgaps based on chemical adjustment of the s- and p-orbital character of the conduction band minimum. To demonstrate the viability of the design strategy, we successfully synthesized a family of double perovskites: Cs₂AgSbCl₆ with an indirect bandgap and Cs₂AgInCl₆ with a direct bandgap and the solid solutions between the two.