Donor-acceptor photoexcitation dynamics in organic blends investigated with a high sensitivity pump-probe systemElectronic supplementary information (ESI) available: Estimation of the photon flux, emission spectra, discussion on the time resolution. See DOI: 10.1039/c8tc03118e
Optical pump-probe spectroscopy is a crucial tool to investigate the excited state behaviour of materials and is especially useful to investigate the photoexcitation dynamics of bulk heterojunctions as found in organic solar cells. Most common techniques for such investigations involve pulses with a...
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Main Authors | , , , |
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Format | Journal Article |
Published |
18.10.2018
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Online Access | Get full text |
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Summary: | Optical pump-probe spectroscopy is a crucial tool to investigate the excited state behaviour of materials and is especially useful to investigate the photoexcitation dynamics of bulk heterojunctions as found in organic solar cells. Most common techniques for such investigations involve pulses with an energy density in the range of several tens of μJ cm
−2
, emitted with kHz repetition rate. Such pulse energy can entail non-linear processes due to the formation of high carrier concentrations and can furthermore severely damage the sample material. Here we introduce a softer approach with pulses of nJ cm
−2
energy density and a photon flux which is more than three orders of magnitude lower than in regular techniques. We show the capability of our low-cost and easy to make set-up by investigating two prototypical donor-acceptor polymers, C-PCPDTBT and its silicon variant Si-PCPDTBT. Given the high pulse repetition rate in the MHz regime, we are readily able to monitor sample changes of 10
−5
and find exciton lifetimes of 108 and 150 ps for C- and Si-PCPDTBT respectively.
The excited state dynamics of conjugated polymers are studied at photon fluences relevant for photovoltaic applications. |
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Bibliography: | Electronic supplementary information (ESI) available: Estimation of the photon flux, emission spectra, discussion on the time resolution. See DOI 10.1039/c8tc03118e |
ISSN: | 2050-7526 2050-7534 |
DOI: | 10.1039/c8tc03118e |