Static and Dynamic Disorder in Triple-Cation Hybrid Perovskites

TL;DR

This study investigates how static and dynamic lattice disorder in triple-cation hybrid perovskites affects their carrier dynamics and emission, revealing temperature-dependent changes in disorder and their impact on photoluminescence efficiency.

Contribution

It provides new insights into the evolution of lattice disorder from static to dynamic with temperature and its effect on emission properties in hybrid perovskites.

Findings

Disorder creates sub-bandgap tail states affecting emission.

Temperature increases cause disorder to shift from static to dynamic.

PL efficiency drops rapidly with temperature due to increased non-radiative recombination.

Abstract

A detailed understanding of the carrier dynamics and emission characteristics of organic-inorganic lead halide perovskites is critical for their optoelectronic and energy harvesting applications. In this work, we reveal the impact of the crystal lattice disorder on the photo-generated electron-hole pairs through low-temperature photoluminescence measurements. We provide strong evidence that the intrinsic disorder forms a sub-bandgap tail density of states, which determines the emission properties at low temperature. The PL spectra indicate that the disorder evolves with increasing temperature, changing its character from static to dynamic. This change is accompanied by a rapid drop of the PL efficiency, originating from the increased mobility of excitons/polarons, which enables them to reach deep non-radiative recombination centers more easily.