Document Type
Article
Language
eng
Format of Original
6 p.
Publication Date
8-4-2016
Publisher
American Chemical Society
Source Publication
Journal of Physical Chemistry Letters
Source ISSN
1948-7185
Original Item ID
DOI: 10.1021/acs.jpclett.6b01268; PubMed Central PMID: 27409718
Abstract
Understanding the mechanisms of long-range energy transfer through polychromophoric assemblies is critically important in photovoltaics and biochemical systems. Using a set of cofacially arrayed polyfluorenes (Fn), we investigate the mechanism of (singlet) exciton delocalization in π-stacked polychromophoric assemblies. Calculations reveal that effective stabilization of an excimeric state requires an ideal sandwich-like arrangement; yet surprisingly, emission spectroscopy indicates that exciton delocalization is limited to only two fluorene units for all n. Herein, we show that delocalization is determined by the interplay between the energetic gain from delocalization, which quickly saturates beyond two units in larger Fn, and an energetic penalty associated with structural reorganization, which increases linearly with n. With these insights, we propose a hopping mechanism for exciton transfer, based upon the presence of multiple excimeric tautomers of similar energy in larger polyfluorenes (n ≥ 4) together with the anticipated low thermal barrier of their interconversion.
Recommended Citation
Talipov, Marat R.; Ivanov, Maxim Vadimovich; Reid, Scott; and Rathore, Rajendra, "Two's Company, Three's a Crowd: Exciton Localization in Cofacially Arrayed Polyfluorenes" (2016). Chemistry Faculty Research and Publications. 530.
https://epublications.marquette.edu/chem_fac/530
Comments
Accepted version. Journal of Physical Chemistry Letters, Vol. 7, No. 5 (August 4, 2016): 2915-2920. DOI. © 2016 American Chemical Society. Used with permission.