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Title: Unveiling Multiquantum Excitonic Correlations in Push–Pull Polymer Semiconductors
Bound and unbound Frenkel-exciton pairs are essential transient precursors for a variety of photophysical and biochemical processes. In this work, we identify bound and unbound Frenkel-exciton complexes in an electron push−pull polymer semiconductor using coherent two- dimensional spectroscopy. We find that the dominant A0−1 peak of the absorption vibronic progression is accompanied by a subpeak, each dressed by distinct vibrational modes. By considering the Liouville pathways within a two-exciton model, the imbalanced cross-peaks in one-quantum rephasing and nonrephasing spectra can be accounted for by the presence of pure biexcitons. The two-quantum nonrephasing spectra provide direct evidence for unbound exciton pairs and biexcitons with dominantly attractive force. In addition, the spectral features of unbound exciton pairs show mixed absorptive and dispersive character, implying many-body interactions within the correlated Frenkel-exciton pairs. Our work offers novel perspectives on the Frenkel-exciton complexes in semiconductor polymers.  more » « less
Award ID(s):
1922111
PAR ID:
10531362
Author(s) / Creator(s):
; ; ; ;
Publisher / Repository:
American Chemical Society
Date Published:
Journal Name:
The Journal of Physical Chemistry Letters
Edition / Version:
1
Volume:
15
Issue:
14
ISSN:
1948-7185
Page Range / eLocation ID:
3705 to 3712
Subject(s) / Keyword(s):
push-pull polymers N2200 coherent 2D-spectroscopy excitonic correlations
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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