In high-performance solar cells based on polymeric semiconductors, the mechanism of photocarrier generation on <100-fs timescales is yet to be unravelled. In particular the dynamics of early-time electronic coupling between excitons on polymer chains and charge-transfer states need to be investigated in order to develop a detailed picture of ultrafast processes involved in photocurrent production. In this proceeding, we report preliminary measurements using a novel spectroscopy that can measure such correlations: two-dimensional coherent photocurrent excitation spectroscopy. This nonlinear technique measures off-diagonal spectral correlations in a two-dimensional photocurrent excitation spectrum. We interpret these sectroscopic measurements in light of recent theoretical predictions.
@article{arxiv.1506.07837,
title = {Two-dimensional coherent photocurrent excitation spectroscopy in a polymer solar cell},
author = {Eleonora Vella and Pascal Grégoire and Hao Li and Sachetan M. Tuladhar and Michelle Vezie and Sheridan Few and Jenny Nelson and Eric R. Bittner and Carlos Silva},
journal= {arXiv preprint arXiv:1506.07837},
year = {2015}
}