Intrinsic Defect Properties in Halide Double Perovskites for Optoelectronic Applications

Lead-free halide double perovskites could be useful in optoelectronic applications, such solar cells and photocatalysis. However, a comprehensive understanding of intrinsic defect properties is needed, as defects strongly affect carrier density and transport. First-principles energy calculations are used to investigate representative lead-free halide double perovskites and identify deep defect levels. The authors show how chemical potentials of the constituent elements can be modified, to suppress unwanted defects or to tune the Fermi level. These guidelines will further the exploration of these compounds for use in high-performance optoelectronic devices.