Ultrafast long-range charge separation in organic semiconductor photovoltaic diodes.
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Authors
Gélinas, Simon
Rao, Akshay
Kumar, Abhishek
Smith, Samuel L
Chin, Alex W
Clark, Jenny
van der Poll, Tom S
Bazan, Guillermo C
Friend, Richard H
Publication Date
2014-01-31Journal Title
Science
ISSN
0036-8075
Publisher
American Association for the Advancement of Science (AAAS)
Volume
343
Issue
6170
Pages
512-516
Language
eng
Type
Article
Physical Medium
Print-Electronic
Metadata
Show full item recordCitation
Gélinas, S., Rao, A., Kumar, A., Smith, S. L., Chin, A. W., Clark, J., van der Poll, T. S., et al. (2014). Ultrafast long-range charge separation in organic semiconductor photovoltaic diodes.. Science, 343 (6170), 512-516. https://doi.org/10.1126/science.1246249
Abstract
Understanding the charge-separation mechanism in organic photovoltaic cells (OPVs) could facilitate optimization of their overall efficiency. Here we report the time dependence of the separation of photogenerated electron hole pairs across the donor-acceptor heterojunction in OPV model systems. By tracking the modulation of the optical absorption due to the electric field generated between the charges, we measure ~200 millielectron volts of electrostatic energy arising from electron-hole separation within 40 femtoseconds of excitation, corresponding to a charge separation distance of at least 4 nanometers. At this separation, the residual Coulomb attraction between charges is at or below thermal energies, so that electron and hole separate freely. This early time behavior is consistent with charge separation through access to delocalized π-electron states in ordered regions of the fullerene acceptor material.
Sponsorship
Engineering and Physical Sciences Research Council (EP/G060738/1)
Identifiers
External DOI: https://doi.org/10.1126/science.1246249
This record's URL: https://www.repository.cam.ac.uk/handle/1810/286327
Rights
Licence:
http://www.rioxx.net/licenses/all-rights-reserved
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