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Title: Inherent Driving Force for Charge Separation in Curved Stacks of Oligothiophenes

Journal Article · · Journal of Physical Chemistry. B
DOI:https://doi.org/10.1021/jp510866c· OSTI ID:1213395
 [1]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States). Center for Functional Nanomaterials
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Coexistence of high local charge mobility and an energy gradient can lead to efficient free charge carrier generation from geminate charge transfer states at the donor–acceptor interface in bulk heterojunction organic photovoltaics. It is, however, not clear what polymer microstructures can support such coexistence. Using recent methods from density functional theory, we propose that a stack of similarly curved oligothiophene chains can deliver the requirements for efficient charge separation. Curved stacks are stable because of the polymer’s strong π-stacking ability and because backbone torsions are flexible in neutral chains. However, energy of a charge in a polymer chain has remarkably stronger dependence on torsions. The trend of increasing planarity in curved stacks effectively creates an energy gradient that drives charge in one direction. The curvature of these partially ordered stacks is found to beneficially interact with fullerenes for charge separation. The curved stacks, therefore, are identified as possible building blocks for interfacial structures that lead to efficient free carrier generation in high-performing organic photovoltaic systems.

Research Organization:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
SC00112704
OSTI ID:
1213395
Report Number(s):
BNL-108302-2015-JA; R&D Project: 16068; KC0403020
Journal Information:
Journal of Physical Chemistry. B, Vol. 119, Issue 24; ISSN 1520-6106
Publisher:
American Chemical SocietyCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 8 works
Citation information provided by
Web of Science

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Cited By (2)

Charge generation in organic photovoltaics: a review of theory and computation journal January 2016
Theoretical study on mesoscopic-size impurity effects in the charge separation process of organic photocells journal January 2018

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
polymer microstructures
oligothiophene chains
organic photovoltaic systems