Triplet State Formation in Photovoltaic Blends of DPP-Type Copolymers and PC71BM

Handle URI:
http://hdl.handle.net/10754/553015
Title:
Triplet State Formation in Photovoltaic Blends of DPP-Type Copolymers and PC71BM
Authors:
Ochsmann, Julian R.; Chandran, Deepak; Gehrig, Dominik W.; Anwar, Husna; Madathil, Pramod Kandoth; Lee, Kwang-Sup; Laquai, Frederic ( 0000-0002-5887-6158 )
Abstract:
The exciton dynamics in pristine films of two structurally related low-bandgap diketopyrrolopyrrole (DPP)-based donor–acceptor copolymers and the photophysical processes in bulk heterojunction solar cells using DPP copolymer:PC71BM blends are investigated by broadband transient absorption (TA) pump-probe experiments covering the vis–near-infrared spectral and fs–μs dynamic range. The experiments reveal surprisingly short exciton lifetimes in the pristine poly­mer films in conjunction with fast triplet state formation. An in-depth analysis of the TA data by multivariate curve resolution analysis shows that in blends with fullerene as acceptor ultrafast exciton dissociation creates charge carriers, which then rapidly recombine on the sub-ns timescale. Furthermore, at the carrier densities created by pulsed laser excitation the charge carrier recombination leads to a substantial population of the polymer triplet state. In fact, virtually quantitative formation of triplet states is observed on the sub-ns timescale. However, the quantitative triplet formation on the sub-ns timescale is not in line with the power conversion efficiencies of devices indicating that triplet state formation is an intensity-dependent process in these blends and is reduced under solar illumination conditions, as free charge carriers can be extracted from the photoactive layer in devices.
KAUST Department:
Physical Sciences and Engineering (PSE) Division; Materials Science and Engineering Program; Solar and Photovoltaic Engineering Research Center
Citation:
Ochsmann, J. R., Chandran, D., Gehrig, D. W., Anwar, H., Madathil, P. K., Lee, K.-S. and Laquai, F. (2015), Triplet State Formation in Photovoltaic Blends of DPP-Type Copolymers and PC71BM. Macromol. Rapid Commun.. doi: 10.1002/marc.201400714
Journal:
Macromolecular Rapid Communications
Issue Date:
29-Apr-2015
DOI:
10.1002/marc.201400714
Type:
Article
ISSN:
10221336
Additional Links:
http://doi.wiley.com/10.1002/marc.201400714
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.authorOchsmann, Julian R.en
dc.contributor.authorChandran, Deepaken
dc.contributor.authorGehrig, Dominik W.en
dc.contributor.authorAnwar, Husnaen
dc.contributor.authorMadathil, Pramod Kandothen
dc.contributor.authorLee, Kwang-Supen
dc.contributor.authorLaquai, Fredericen
dc.date.accessioned2015-05-17T20:36:36Zen
dc.date.available2015-05-17T20:36:36Zen
dc.date.issued2015-04-29en
dc.identifier.citationOchsmann, J. R., Chandran, D., Gehrig, D. W., Anwar, H., Madathil, P. K., Lee, K.-S. and Laquai, F. (2015), Triplet State Formation in Photovoltaic Blends of DPP-Type Copolymers and PC71BM. Macromol. Rapid Commun.. doi: 10.1002/marc.201400714en
dc.identifier.issn10221336en
dc.identifier.doi10.1002/marc.201400714en
dc.identifier.urihttp://hdl.handle.net/10754/553015en
dc.description.abstractThe exciton dynamics in pristine films of two structurally related low-bandgap diketopyrrolopyrrole (DPP)-based donor–acceptor copolymers and the photophysical processes in bulk heterojunction solar cells using DPP copolymer:PC71BM blends are investigated by broadband transient absorption (TA) pump-probe experiments covering the vis–near-infrared spectral and fs–μs dynamic range. The experiments reveal surprisingly short exciton lifetimes in the pristine poly­mer films in conjunction with fast triplet state formation. An in-depth analysis of the TA data by multivariate curve resolution analysis shows that in blends with fullerene as acceptor ultrafast exciton dissociation creates charge carriers, which then rapidly recombine on the sub-ns timescale. Furthermore, at the carrier densities created by pulsed laser excitation the charge carrier recombination leads to a substantial population of the polymer triplet state. In fact, virtually quantitative formation of triplet states is observed on the sub-ns timescale. However, the quantitative triplet formation on the sub-ns timescale is not in line with the power conversion efficiencies of devices indicating that triplet state formation is an intensity-dependent process in these blends and is reduced under solar illumination conditions, as free charge carriers can be extracted from the photoactive layer in devices.en
dc.relation.urlhttp://doi.wiley.com/10.1002/marc.201400714en
dc.rightsThis is the peer reviewed version of the following article: Ochsmann, J. R., Chandran, D., Gehrig, D. W., Anwar, H., Madathil, P. K., Lee, K.-S. and Laquai, F. (2015), Triplet State Formation in Photovoltaic Blends of DPP-Type Copolymers and PC71BM. Macromol. Rapid Commun.. doi: 10.1002/marc.201400714, which has been published in final form at http://doi.wiley.com/10.1002/marc.201400714. This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.en
dc.subjectcharge generationen
dc.subjectDPP polymersen
dc.subjectorganic photovoltaicsen
dc.subjecttransient absorption spectroscopyen
dc.subjecttriplet state formationen
dc.titleTriplet State Formation in Photovoltaic Blends of DPP-Type Copolymers and PC71BMen
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 55128 Mainz Germanyen
dc.contributor.institutionDepartment of Advanced Materials; Hannam University; Daejeon 305-811 Koreaen
dc.contributor.institutionMax Planck Research Group for Organic Optoelectronics; Max Planck Institute for Polymer Research; Ackermannweg 10 55128 Mainz Germanyen
dc.contributor.institutionDepartment of Physics; Mount Holyoke College; 50 College St South Hadley MA 01075 USAen
dc.contributor.institutionDepartment of Advanced Materials; Hannam University; Daejeon 305-811 Koreaen
dc.contributor.institutionDepartment of Advanced Materials; Hannam University; Daejeon 305-811 Koreaen
dc.contributor.institutionMax Planck Research Group for Organic Optoelectronics; Max Planck Institute for Polymer Research; Ackermannweg 10 55128 Mainz Germanyen
dc.contributor.institutionSchool of Chemical Sciences & National Institute for Cellular Biotechnology, Dublin City University, Glasnevin, Dublin-9, Irelanden
kaust.authorLaquai, Fredericen
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