Probing polaron excitation spectra in organic semiconductors by photoinduced-absorption-detected two-dimensional coherent spectroscopy

TL;DR

This paper introduces a new 2D coherent excitation spectroscopy technique using photoinduced absorption to study polaron excitations in organic semiconductors, combining theory and experiments.

Contribution

It presents a novel theoretical and experimental approach for probing polaron spectra in organic semiconductors with a photoinduced absorption-based 2D spectroscopy.

Findings

Photoinduced absorption is effective for 2D spectroscopy of polaron states.

The method provides detailed insights into polaron excitation spectra.

Experimental results validate the theoretical model.

Abstract

We report a theoretical description and experimental implementation of a novel two-dimensional coherent excitation spectroscopy based on quasi-steady-state photoinduced absorption measurement of a long-lived nonlinear population. We have studied a semiconductor-polymer:fullerene-derivative distributed heterostructure by measuring the 2D excitation spectrum by means of photoluminescence, photocurrent and photoinduced absorption from metastable polaronic products. We conclude that the photoinduced absorption probe is a viable and valuable probe in this family of 2D coherent spectroscopies.