Intrinsic femtosecond charge generation dynamics in a single crystal organometal halide perovskite

TL;DR

This study uses ultrabroadband THz pulses to investigate the femtosecond-scale charge generation and dynamics in single crystal lead halide perovskite, revealing insights into free charge creation and mobility.

Contribution

It provides the first direct ultrafast spectroscopic measurements of intrinsic charge generation dynamics in single crystal perovskite, elucidating fundamental photophysical processes.

Findings

Revealed femtosecond charge creation dynamics

Demonstrated high mobility of free charges

Uncovered complex interplay between free and bound charges

Abstract

Hybrid metal-organic perovskite solar cells have astounded the solar cell community with their rapid rise in efficiency over the past three years. Despite this success, the basic processes governing the photogeneration of free charges, particularly their dynamics and efficiency, remain unknown. Here we use ultrabroadband pulses of THz frequency light to see the intrinsic photophysical properties of single crystal lead halide perovskite just femtoseconds after a photon is first absorbed. Our spectra reveal the dynamics and efficiencies of free charge creation, the remarkable ease in which they move through the lattice and the complicated interplay between free and bound charges in these materials.