Are Shockley-Read-Hall and ABC models valid for lead halide perovskites?

Metal halide perovskites are an important class of emerging semiconductors. Their charge carrier dynamics is poorly understood due to limited knowledge of defect physics and charge carrier recombination mechanisms. Nevertheless, classical ABC and Shockley-Read-Hall (SRH) models are ubiquitously applied to perovskites without considering their validity. Herein, an advanced technique mapping photoluminescence quantum yield (PLQY) as a function of both the excitation pulse energy and repetition frequency is developed and employed to examine the validity of these models. While ABC and SRH fail to explain the charge dynamics in a broad range of conditions, the addition of Auger recombination and trapping to the SRH model enables a quantitative fitting of PLQY maps and low-power PL decay kinetics, and extracting trap concentrations and efficacies. However, PL kinetics at high power are too fast and cannot be explained. The proposed PLQY mapping technique is ideal for a comprehensive testing of theories and applicable to any semiconductor. Charge dynamics in perovskite is not well-understood, limited by the knowledge of defect physics and charge recombination mechanism, yet the ABC and SRH models are widely used. Here, the authors introduce advanced PLQY mapping as function of excitation pulse energy and repetition frequency to examine the validity of these models.

Automated summary

Metal halide perovskites are an important class of emerging semiconductors, but their charge carrier dynamics is not well understood. Researchers have developed an advanced technique to examine the validity of models used to understand the charge dynamics in perovskites.