Beyond 1 ms Charge-Carrier Recombination Dynamics in the CsPbBr3 Perovskite

TL;DR

This study reveals that CsPbBr3 perovskite exhibits charge-carrier recombination lifetimes exceeding 1 ms at low temperatures and approaching 100 microseconds at room temperature, with impurity trapping dominating the dynamics.

Contribution

The paper provides the first detailed measurement and modeling of ultra-long charge-carrier lifetimes in CsPbBr3, highlighting impurity trapping as a key factor.

Findings

Recombination lifetime exceeds 1 ms below 200 K.

Lifetime approaches 100 microseconds at room temperature.

Impurity charge trapping dominates recombination dynamics.

Abstract

Knowledge of the charge-carrier recombination lifetime, tau, is crucial for the various applications of photovoltaic perovskites. We studied the novel inorganic perovskite, CsPbBr3 and we observe recombination dynamics beyond 1 ms below 200 K and tau approaching 100 us at room temperature. Time-resolved microwave-detected photoconductivity decay (TRMCD), used in combination with injection dependence, evidence that tau is dominated by impurity charge trapping. The observed injection dependence is well corroborated by modeling of the trap mechanism. The ultra-long decay time is also consistent with photoconductivity measurements with a continuous-wave excitation at powers corresponding to around one Sun irradiation. While in principle charge-carrier trapping may limit the photovoltaic efficiency in single-cell photovoltaic devices, it could also lead to enhanced efficiency in tandem cells as well as for alternative applications including photodetection and quantum information storage.