Heilweil, E.
, Lane, P.
, Cunningham, P.
and Melinger, J.
(2015),
Direct Observation of Carrier Cooling in Organic Semiconductors, Nature Materials, [online], https://doi.org/10.1038/ncomms8558
(Accessed February 12, 2025)
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Direct Observation of Carrier Cooling in Organic Semiconductors
Published
Author(s)
, Paul A. Lane, Paul D. Cunningham, Joseph S. Melinger
Abstract
Photocurrent in an organic solar cell is generated by a charge transfer reaction between the electron donor and acceptor. The effect of excess excitation energy and the relative contributions of electron and hole transfer are the subject of intense scrutiny. Here we directly study photoconductivity on the sub-picosecond time scale by time-resolved terahertz (TRTS) and transient absorption (TA) spectroscopies. Charge transfer from an excited electron donor generates a hot electron that localizes within a picosecond, demonstrating a direct link between excess excitation energy and photocarrier mobility. On the other hand, charge transfer after excitation of the electron acceptorgenerates a localized carrier with terahertz photoconductivity dynamics consisting of an instrument limited rise to a long-lived signal. The long-lived photoconductivity is not sensitive to the hole mobility of the electron donor, leading us to assign it to electrons (C60 anions).Citation
Nature Materials
Pub Type
Journals
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Keywords
photovoltaics, solar cells, photcarrier mobility, time-resolved terahertz, transient absorption, photoionization, hot carriers
Citation
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Created July 16, 2015, Updated November 10, 2018