Effective Lifetime of Nonequilibrium Carriers in Perovskite‐Inspired Cu2AgBiI6

Abstract

Perovskite‐inspired materials (PIMs) are potential alternatives to lead halide perovskites, as they not only inherit the benign optoelectronic properties but also diminish the stability and toxicity issues of lead halide perovskites. As a newly discovered PIM, Cu2AgBiI6 has exhibited promising potential for photovoltaic applications. However, studies on its fundamental properties related to photovoltaic performance are scarce, particularly from a theoretical perspective. Herein, the effective lifetime of nonequilibrium carriers (photo‐excited charge carriers) is systematically investigated, a critical property affecting the photovoltaic performance of Cu2AgBiI6, based on the nonadiabatic molecular dynamics simulations. It is found that under the standard solar spectrum illumination, the dominant recombination mechanism affecting the effective lifetime can be band‐to‐band nonradiative decay, band‐to‐band radiative decay, or Shockey–Read–Hall defect‐assisted decay. The specific mechanism is highly dependent on the radiative recombination coefficient and the density of defect recombination levels. The effective lifetime can vary from 0.1 ms to 10 ns. When considering different illumination conditions (generation rates), Auger decay can also become the dominant recombination mechanism, with the effective lifetime varying from 0.1 s to 0.1 ns. These findings can be vital for further experimental researches aimed at enhancing the power conversion efficiency of Cu2AgBiI6‐based solar devices.