Searching for “defect-tolerant” photovoltaic materials: combined theoretical and experimental screening

Abstract

Recently, we and others have proposed screening criteria for "defect-tolerant" photovoltaic (PV) absorbers, identifying several classes of semiconducting compounds with electronic structures similar to those of hybrid lead halide perovskites. In this work, we reflect on the accuracy and prospects of these new design criteria through a combined experimental and theoretical approach. We construct a model to extract photoluminescence lifetimes Of six of these candidate PV absorbers, including four (InI, SbSI, SbSeI, arid BiOI) for which time-resolved photoluminescence has not been previously reported. The lifetimes of all six candidate materials exceed 1 ns, a threshold for promising early stage PV device performance. However, there are variations between these materials, and none achieve lifetimes as high as those of the hybrid lead halide perovskites, suggesting that the heuristics for defect-tolerant semiconductors are incomplete. We explore this through first principles point defect calculations and Shockley-Read-Hall recombination models to describe the variation between the measured materials. In light of these insights, we discuss the evolution of screening criteria for defect tolerance and high-performance PV materials.