Mobile defects as mediated states for charge-carrier trapping in metal halide perovskites quantum dots

TL;DR

This study reveals that two-step charge-carrier trapping mediated by mobile defects in metal halide perovskite quantum dots is significantly faster than direct trapping, impacting non-radiative recombination and device performance.

Contribution

It introduces a full-configuration defect method to analyze two-step trapping processes mediated by mobile defects in MHPQDs, highlighting their role in non-radiative losses.

Findings

Two-step trapping is an order of magnitude faster than direct trapping.

Mobile defects with appropriate localization significantly influence trapping rates.

The model explains non-radiative processes observed in experiments.

Abstract

The migration motion of defects in metal halide perovskites quantum dots (MHPQDs) results in charge-carrier trapping become more complicated. We study two-step trapping mediated by mobile defects between the ground state of MHPQDs and a fixed-depth defect using a full-configuration defect method, where all possible trapping processes mediated by these mobile defects could be reproduced and the fastest channels among them are picked out. We find that these two-step trapping processes could keep more one order of magnitude faster than these direct ones as mobile defect with the appropriate localization strength, which implies that these indirect trapping should play the crucial rule to determine the non-radiative recombination losses. These results provide the significant explanation for studying non-radiation processes of carriers in the presence of the migration defects in recent experiments. Moreover, this model will be available to analyze some key performance related defects in electronic devices.