Exploring the properties of lead-free hybrid double perovskites using a combined computational-experimental approach

Abstract

Density functional theory screening of the hybrid double perovskites (MA)₂B^IBiX₆ (B^I = K, Cu, Ag, Tl; X = Cl, Br, I) shows that systems with band gaps similar to those of the MAPbX₃ lead compounds can be expected for B^I = Cu, Ag, Tl. Motivated by these findings, (MA)₂TlBiBr₆, isoelectronic with MAPbBr₃, was synthesised and found to have a band gap of ∼2.0 eV.