Exciton dynamics and non-linearities in 2D-hybrid organic perovskites

TL;DR

This paper investigates exciton dynamics and nonlinear optical properties in 2D hybrid organic perovskites, revealing ultrafast relaxation, exciton lifetime, and nonlinear behaviors similar to inorganic semiconductors, relevant for optoelectronic applications.

Contribution

It provides experimental insights into exciton nonlinearities and dynamics in 2D hybrid organic perovskites, highlighting their similarities to inorganic semiconductors.

Findings

Exciton lifetime of approximately 100 ps.

Ultrafast intraband relaxation below 150 fs.

Nonlinear behaviors akin to inorganic semiconductors.

Abstract

Due to their high potentiality for photovoltaic applications or coherent light sources, a renewed interest in hybrid organic perovskites has emerged for few years. When they are arranged in two dimensions, these materials can be considered as hybrids quantum wells. One consequence of the unique structure of 2D hybrid organic perovskites is a huge exciton binding energy that can be tailored through chemical engineering. We present experimental investigations of the exciton nonlinearities by means of femtosecond pump-probe spectroscopy. The exciton dynamics is fitted with a bi-exponential decay with a free exciton life-time of ~100 ps. Moreover, an ultrafast intraband relaxation (< 150 fs) is also reported. Finally, the transient modification of the excitonic line is analysed through the momenta analysis and described in terms of reduction of the oscillator strength and linewidth broadening. We show that excitonic non-linearities in 2D hybrid organic perovskites share some behaviours of inorganic semiconductors despite their huge exciton binding energy.