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

TL;DR

This study critically evaluates the applicability of classical charge recombination models to lead halide perovskites, revealing their limitations and proposing an enhanced model incorporating Auger recombination and trapping for better accuracy.

Contribution

The paper introduces a novel PLQY mapping technique to test the validity of ABC and SRH models in perovskites, and extends these models with additional processes for improved fit.

Findings

Classical ABC and SRH models fail to fully explain charge dynamics in perovskites.

Adding Auger recombination and trapping improves model fit to PLQY maps.

Higher-power kinetics require additional non-linear processes.

Abstract

Metal halide perovskites are an important class of emerging semiconductors. Their charge dynamics is poorly understood due to limited knowledge of defect physics and charge 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. Higher-power PL kinetics requires the inclusion of additional non-linear processes. The PLQY mapping developed herein is suitable for a comprehensive testing of theories and is applicable to any semiconductor.