Direct observation of ultrafast long-range charge separation at polymer–fullerene heterojunctions

Handle URI:
http://hdl.handle.net/10754/596991
Title:
Direct observation of ultrafast long-range charge separation at polymer–fullerene heterojunctions
Authors:
Provencher, Françoise; Bérubé, Nicolas; Parker, Anthony W.; Greetham, Gregory M.; Towrie, Michael; Hellmann, Christoph; Côté, Michel; Stingelin, Natalie; Silva, Carlos; Hayes, Sophia C.
Abstract:
In polymeric semiconductors, charge carriers are polarons, which means that the excess charge deforms the molecular structure of the polymer chain that hosts it. This results in distinctive signatures in the vibrational modes of the polymer. Here, we probe polaron photogeneration dynamics at polymer:fullerene heterojunctions by monitoring its time-resolved resonance-Raman spectrum following ultrafast photoexcitation. We conclude that polarons emerge within 300 fs. Surprisingly, further structural evolution on ≤50-ps timescales is modest, indicating that the polymer conformation hosting nascent polarons is not significantly different from that near equilibrium. We interpret this as suggestive that charges are free from their mutual Coulomb potential because we would expect rich vibrational dynamics associated with charge-pair relaxation. We address current debates on the photocarrier generation mechanism at molecular heterojunctions, and our work is, to our knowledge, the first direct probe of molecular conformation dynamics during this fundamentally important process in these materials. © 2014 Macmillan Publishers Limited. All rights reserved.
Citation:
Provencher F, Bérubé N, Parker AW, Greetham GM, Towrie M, et al. (2014) Direct observation of ultrafast long-range charge separation at polymer–fullerene heterojunctions. Nat Comms 5. Available: http://dx.doi.org/10.1038/ncomms5288.
Publisher:
Nature Publishing Group
Journal:
Nature Communications
Issue Date:
1-Jul-2014
DOI:
10.1038/ncomms5288
PubMed ID:
24980429
Type:
Article
ISSN:
2041-1723
Sponsors:
C.S. acknowledges funding from the Natural Sciences and Engineering Research Council of Canada, the Canada Research Chair in Organic Semiconductor Materials, the Royal Society and the Leverhulme Trust. The research leading to these results has received funding from LASERLAB-EUROPE (grant agreement no. 284464, EC's Seventh Framework Programme). N.S. and C.H. acknowledge funding from the UK Engineering and Physical Sciences Research Council EP/G060738/1 grant, the European Research Council (ERC) Starting Independent Research Fellowship under the grant agreement No. 279587 and King Abdullah University of Science and Technology (KAUST CRG). We acknowledge the assistance of A. Scaccabarozzi for film deposition and are grateful to Serge Beaupre and Mario Leclerc for providing the PCDTBT. S.C.H. and C.S. are grateful for illuminating discussions with David McCamant and Philip Reid.
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Full metadata record

DC FieldValue Language
dc.contributor.authorProvencher, Françoiseen
dc.contributor.authorBérubé, Nicolasen
dc.contributor.authorParker, Anthony W.en
dc.contributor.authorGreetham, Gregory M.en
dc.contributor.authorTowrie, Michaelen
dc.contributor.authorHellmann, Christophen
dc.contributor.authorCôté, Michelen
dc.contributor.authorStingelin, Natalieen
dc.contributor.authorSilva, Carlosen
dc.contributor.authorHayes, Sophia C.en
dc.date.accessioned2016-02-23T13:51:59Zen
dc.date.available2016-02-23T13:51:59Zen
dc.date.issued2014-07-01en
dc.identifier.citationProvencher F, Bérubé N, Parker AW, Greetham GM, Towrie M, et al. (2014) Direct observation of ultrafast long-range charge separation at polymer–fullerene heterojunctions. Nat Comms 5. Available: http://dx.doi.org/10.1038/ncomms5288.en
dc.identifier.issn2041-1723en
dc.identifier.pmid24980429en
dc.identifier.doi10.1038/ncomms5288en
dc.identifier.urihttp://hdl.handle.net/10754/596991en
dc.description.abstractIn polymeric semiconductors, charge carriers are polarons, which means that the excess charge deforms the molecular structure of the polymer chain that hosts it. This results in distinctive signatures in the vibrational modes of the polymer. Here, we probe polaron photogeneration dynamics at polymer:fullerene heterojunctions by monitoring its time-resolved resonance-Raman spectrum following ultrafast photoexcitation. We conclude that polarons emerge within 300 fs. Surprisingly, further structural evolution on ≤50-ps timescales is modest, indicating that the polymer conformation hosting nascent polarons is not significantly different from that near equilibrium. We interpret this as suggestive that charges are free from their mutual Coulomb potential because we would expect rich vibrational dynamics associated with charge-pair relaxation. We address current debates on the photocarrier generation mechanism at molecular heterojunctions, and our work is, to our knowledge, the first direct probe of molecular conformation dynamics during this fundamentally important process in these materials. © 2014 Macmillan Publishers Limited. All rights reserved.en
dc.description.sponsorshipC.S. acknowledges funding from the Natural Sciences and Engineering Research Council of Canada, the Canada Research Chair in Organic Semiconductor Materials, the Royal Society and the Leverhulme Trust. The research leading to these results has received funding from LASERLAB-EUROPE (grant agreement no. 284464, EC's Seventh Framework Programme). N.S. and C.H. acknowledge funding from the UK Engineering and Physical Sciences Research Council EP/G060738/1 grant, the European Research Council (ERC) Starting Independent Research Fellowship under the grant agreement No. 279587 and King Abdullah University of Science and Technology (KAUST CRG). We acknowledge the assistance of A. Scaccabarozzi for film deposition and are grateful to Serge Beaupre and Mario Leclerc for providing the PCDTBT. S.C.H. and C.S. are grateful for illuminating discussions with David McCamant and Philip Reid.en
dc.publisherNature Publishing Groupen
dc.rightsOpen access articles are published under a CC BY license (Creative Commons Attribution 4.0 International License).en
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/en
dc.titleDirect observation of ultrafast long-range charge separation at polymer–fullerene heterojunctionsen
dc.typeArticleen
dc.identifier.journalNature Communicationsen
dc.contributor.institutionUniversite de Montreal, Montreal, Canadaen
dc.contributor.institutionScience and Technology Facilities Council, Swindon, United Kingdomen
dc.contributor.institutionImperial College London, London, United Kingdomen
dc.contributor.institutionImperial College London, London, United Kingdomen
dc.contributor.institutionUniversity of Cyprus, Nicosia, Cyprusen

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