The Impact of Donor-Acceptor Phase Separation on the Charge Carrier Dynamics in pBTTT:PCBM Photovoltaic Blends

Handle URI:
http://hdl.handle.net/10754/553017
Title:
The Impact of Donor-Acceptor Phase Separation on the Charge Carrier Dynamics in pBTTT:PCBM Photovoltaic Blends
Authors:
Gehrig, Dominik W.; Howard, Ian A.; Sweetnam, Sean; Burke, Timothy M.; McGehee, Michael D.; Laquai, Frederic ( 0000-0002-5887-6158 )
Abstract:
The effect of donor–acceptor phase separation, controlled by the donor–acceptor mixing ratio, on the charge generation and recombination dynamics in pBTTT-C14:PC70BM bulk heterojunction photovoltaic blends is presented. Transient absorption (TA) spectroscopy spanning the dynamic range from pico- to microseconds in the visible and near-infrared spectral regions reveals that in a 1:1 blend exciton dissociation is ultrafast; however, charges cannot entirely escape their mutual Coulomb attraction and thus predominantly recombine geminately on a sub-ns timescale. In contrast, a polymer:fullerene mixing ratio of 1:4 facilitates the formation of spatially separated, that is free, charges and reduces substantially the fraction of geminate charge recombination, in turn leading to much more efficient photovoltaic devices. This illustrates that spatially extended donor or acceptor domains are required for the separation of charges on an ultrafast timescale (<100 fs), indicating that they are not only important for efficient charge transport and extraction, but also critically influence the initial stages of free charge carrier formation.
KAUST Department:
Physical Sciences and Engineering (PSE) Division; Materials Science and Engineering Program; Solar and Photovoltaic Engineering Research Center
Citation:
The Impact of Donor-Acceptor Phase Separation on the Charge Carrier Dynamics in pBTTT:PCBM Photovoltaic Blends 2015:n/a Macromolecular Rapid Communications
Journal:
Macromolecular Rapid Communications
Issue Date:
7-Apr-2015
DOI:
10.1002/marc.201500112
Type:
Article
ISSN:
10221336
Additional Links:
http://doi.wiley.com/10.1002/marc.201500112
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Materials Science and Engineering Program; Solar and Photovoltaic Engineering Research Center (SPERC)

Full metadata record

DC FieldValue Language
dc.contributor.authorGehrig, Dominik W.en
dc.contributor.authorHoward, Ian A.en
dc.contributor.authorSweetnam, Seanen
dc.contributor.authorBurke, Timothy M.en
dc.contributor.authorMcGehee, Michael D.en
dc.contributor.authorLaquai, Fredericen
dc.date.accessioned2015-05-17T20:38:33Zen
dc.date.available2015-05-17T20:38:33Zen
dc.date.issued2015-04-07en
dc.identifier.citationThe Impact of Donor-Acceptor Phase Separation on the Charge Carrier Dynamics in pBTTT:PCBM Photovoltaic Blends 2015:n/a Macromolecular Rapid Communicationsen
dc.identifier.issn10221336en
dc.identifier.doi10.1002/marc.201500112en
dc.identifier.urihttp://hdl.handle.net/10754/553017en
dc.description.abstractThe effect of donor–acceptor phase separation, controlled by the donor–acceptor mixing ratio, on the charge generation and recombination dynamics in pBTTT-C14:PC70BM bulk heterojunction photovoltaic blends is presented. Transient absorption (TA) spectroscopy spanning the dynamic range from pico- to microseconds in the visible and near-infrared spectral regions reveals that in a 1:1 blend exciton dissociation is ultrafast; however, charges cannot entirely escape their mutual Coulomb attraction and thus predominantly recombine geminately on a sub-ns timescale. In contrast, a polymer:fullerene mixing ratio of 1:4 facilitates the formation of spatially separated, that is free, charges and reduces substantially the fraction of geminate charge recombination, in turn leading to much more efficient photovoltaic devices. This illustrates that spatially extended donor or acceptor domains are required for the separation of charges on an ultrafast timescale (<100 fs), indicating that they are not only important for efficient charge transport and extraction, but also critically influence the initial stages of free charge carrier formation.en
dc.relation.urlhttp://doi.wiley.com/10.1002/marc.201500112en
dc.rightsThis is the peer reviewed version of the following article: Gehrig, D. W., Howard, I. A., Sweetnam, S., Burke, T. M., McGehee, M. D. and Laquai, F. (2015), The Impact of Donor–Acceptor Phase Separation on the Charge Carrier Dynamics in pBTTT:PCBM Photovoltaic Blends. Macromol. Rapid Commun.. doi: 10.1002/marc.201500112, which has been published in final form at http://doi.wiley.com/10.1002/marc.201500112. This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.en
dc.subjectcarrier dynamicsen
dc.subjectpBTTTen
dc.subjectphase separationen
dc.subjectpolymer solar cellsen
dc.subjecttransient absorption spectroscopyen
dc.titleThe Impact of Donor-Acceptor Phase Separation on the Charge Carrier Dynamics in pBTTT:PCBM Photovoltaic Blendsen
dc.typeArticleen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentMaterials Science and Engineering Programen
dc.contributor.departmentSolar and Photovoltaic Engineering Research Centeren
dc.identifier.journalMacromolecular Rapid Communicationsen
dc.eprint.versionPost-printen
dc.contributor.institutionMax Planck Research Group for Organic Optoelectronics; Max Planck Institute for Polymer Research; Ackermannweg 10 D-55128 Mainz Germanyen
dc.contributor.institutionInstitute of Microstructure Technology (IMT); Karlsruhe Institute of Technology (KIT); Hermann-von-Helmholtz-Platz 1 D-76344 Eggenstein-Leopoldshafen Germanyen
dc.contributor.institutionMaterials Science and Engineering; Stanford University; 476 Lomita Mall Stanford CA 94305-4045 USAen
dc.contributor.institutionMaterials Science and Engineering; Stanford University; 476 Lomita Mall Stanford CA 94305-4045 USAen
dc.contributor.institutionMaterials Science and Engineering; Stanford University; 476 Lomita Mall Stanford CA 94305-4045 USAen
dc.contributor.institutionMax Planck Research Group for Organic Optoelectronics; Max Planck Institute for Polymer Research; Ackermannweg 10 D-55128 Mainz Germanyen
kaust.authorLaquai, Fredericen
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