Photoluminescence efficiency droop in Perovskites

TL;DR

This paper models the physical mechanisms behind luminescence efficiency droop in perovskite LEDs at high carrier densities, highlighting the role of self-heating and non-radiative processes, supported by experimental validation.

Contribution

It provides a detailed thermal and carrier dynamics model explaining efficiency droop in perovskites, a novel insight for improving device stability and performance.

Findings

Self-heating reduces radiative recombination efficiency.

Non-radiative recombination increases with temperature.

Model predictions align with experimental data.

Abstract

The commercialization prospects of perovskite light emitting diodes depend on its luminescence efficiency under large carrier densities. The decrease in luminescence efficiency under such high injection conditions could lead to an undesired increase in power consumption with associated degradation and stability concerns. Here, through detailed modeling of thermal transport and carrier generation-recombination, we unravel the physical mechanisms that cause luminescence droop under high injection conditions. We show that self-heating leads to a reduction in the radiative recombination (both bimolecular and excitonic). The resultant increase in non-radiative recombination and hence the thermal dissipation acts as a positive feedback mechanism that leads to efficiency droop in perovskites. Our model predictions, well supported by experimental results, could be of broad interest towards the degradation-aware thermal design of perovskite optoelectronics and stability.