Intercalated vs Non-Intercalated Morphologies in Donor-Acceptor Bulk Heterojunction Solar Cells: PBTTT:Fullerene Charge Generation and Recombination Revisited

Handle URI:
http://hdl.handle.net/10754/625315
Title:
Intercalated vs Non-Intercalated Morphologies in Donor-Acceptor Bulk Heterojunction Solar Cells: PBTTT:Fullerene Charge Generation and Recombination Revisited
Authors:
Collado Fregoso, Elisa; Hood, Samantha N.; Shoaee, Safa; Schroeder, Bob C.; McCulloch, Iain ( 0000-0002-6340-7217 ) ; Kassal, Ivan; Neher, Dieter; Durrant, James R.
Abstract:
In this contribution, we study the role of the donor:acceptor interface nanostructure upon charge separation and recombination in organic photovoltaic devices and blend films, using mixtures of PBTTT and two different fullerene derivatives (PC70BM and ICTA) as models for intercalated and non-intercalated morphologies, respectively. Thermodynamic simulations show that while the completely intercalated system exhibits a large free-energy barrier for charge separation, this barrier is significantly lower in the non-intercalated system, and almost vanishes when energetic disorder is included in the model. Despite these differences, both fs-resolved transient absorption spectroscopy (TAS) and TDCF exhibit extensive first-order losses in that system, suggesting that geminate pairs are the primary product of photoexcitation. In contrast, the system that comprises a combination of fully intercalated polymer:fullerene areas and fullerene aggregated domains (1:4 PBTTT:PC70BM), is the only one that shows slow, second-order recombination of free charges, resulting in devices with an overall higher short circuit current and fill factor. This study therefore provides a novel consideration of the role of the interfacial nanostructure and the nature of bound charges, and their impact upon charge generation and recombination.
KAUST Department:
KSC, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
Citation:
Collado Fregoso E, Hood SN, Shoaee S, Schroeder BC, McCulloch I, et al. (2017) Intercalated vs Non-Intercalated Morphologies in Donor-Acceptor Bulk Heterojunction Solar Cells: PBTTT:Fullerene Charge Generation and Recombination Revisited. The Journal of Physical Chemistry Letters. Available: http://dx.doi.org/10.1021/acs.jpclett.7b01571.
Publisher:
American Chemical Society (ACS)
Journal:
The Journal of Physical Chemistry Letters
Issue Date:
4-Aug-2017
DOI:
10.1021/acs.jpclett.7b01571
Type:
Article
ISSN:
1948-7185
Sponsors:
This work was funded by UNVEiL, a BMBF project, the EPSRC (EP/IO1927B/1, EP/M023532/1 and EP/K011987/1) and the Welsh Assembly Government Sêr Cymru programme. ECF thanks CONACyT (scholarship 309929) and the Kernahan Fund from Imperial College London for funding. SNH and IK were supported by the Westpac Bicentennial Foundation and by the Australian Research Council through a Discovery Early Career Researcher Award (DE140100433) and through the Centre of Excellence for Engineered Quantum Systems (CE110001013).
Additional Links:
http://pubs.acs.org/doi/abs/10.1021/acs.jpclett.7b01571
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Articles

Full metadata record

DC FieldValue Language
dc.contributor.authorCollado Fregoso, Elisaen
dc.contributor.authorHood, Samantha N.en
dc.contributor.authorShoaee, Safaen
dc.contributor.authorSchroeder, Bob C.en
dc.contributor.authorMcCulloch, Iainen
dc.contributor.authorKassal, Ivanen
dc.contributor.authorNeher, Dieteren
dc.contributor.authorDurrant, James R.en
dc.date.accessioned2017-08-10T11:43:34Z-
dc.date.available2017-08-10T11:43:34Z-
dc.date.issued2017-08-04en
dc.identifier.citationCollado Fregoso E, Hood SN, Shoaee S, Schroeder BC, McCulloch I, et al. (2017) Intercalated vs Non-Intercalated Morphologies in Donor-Acceptor Bulk Heterojunction Solar Cells: PBTTT:Fullerene Charge Generation and Recombination Revisited. The Journal of Physical Chemistry Letters. Available: http://dx.doi.org/10.1021/acs.jpclett.7b01571.en
dc.identifier.issn1948-7185en
dc.identifier.doi10.1021/acs.jpclett.7b01571en
dc.identifier.urihttp://hdl.handle.net/10754/625315-
dc.description.abstractIn this contribution, we study the role of the donor:acceptor interface nanostructure upon charge separation and recombination in organic photovoltaic devices and blend films, using mixtures of PBTTT and two different fullerene derivatives (PC70BM and ICTA) as models for intercalated and non-intercalated morphologies, respectively. Thermodynamic simulations show that while the completely intercalated system exhibits a large free-energy barrier for charge separation, this barrier is significantly lower in the non-intercalated system, and almost vanishes when energetic disorder is included in the model. Despite these differences, both fs-resolved transient absorption spectroscopy (TAS) and TDCF exhibit extensive first-order losses in that system, suggesting that geminate pairs are the primary product of photoexcitation. In contrast, the system that comprises a combination of fully intercalated polymer:fullerene areas and fullerene aggregated domains (1:4 PBTTT:PC70BM), is the only one that shows slow, second-order recombination of free charges, resulting in devices with an overall higher short circuit current and fill factor. This study therefore provides a novel consideration of the role of the interfacial nanostructure and the nature of bound charges, and their impact upon charge generation and recombination.en
dc.description.sponsorshipThis work was funded by UNVEiL, a BMBF project, the EPSRC (EP/IO1927B/1, EP/M023532/1 and EP/K011987/1) and the Welsh Assembly Government Sêr Cymru programme. ECF thanks CONACyT (scholarship 309929) and the Kernahan Fund from Imperial College London for funding. SNH and IK were supported by the Westpac Bicentennial Foundation and by the Australian Research Council through a Discovery Early Career Researcher Award (DE140100433) and through the Centre of Excellence for Engineered Quantum Systems (CE110001013).en
dc.publisherAmerican Chemical Society (ACS)en
dc.relation.urlhttp://pubs.acs.org/doi/abs/10.1021/acs.jpclett.7b01571en
dc.rightsThis document is the Accepted Manuscript version of a Published Work that appeared in final form in The Journal of Physical Chemistry Letters, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/acs.jpclett.7b01571.en
dc.titleIntercalated vs Non-Intercalated Morphologies in Donor-Acceptor Bulk Heterojunction Solar Cells: PBTTT:Fullerene Charge Generation and Recombination Revisiteden
dc.typeArticleen
dc.contributor.departmentKSC, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabiaen
dc.identifier.journalThe Journal of Physical Chemistry Lettersen
dc.eprint.versionPost-printen
dc.contributor.institutionCentre for Plastic Electronics, Department of Chemistry, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdomen
dc.contributor.institutionDepartment of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Straße 24–25,14476 Potsdam-Golm, Germanyen
dc.contributor.institutionCentre for Engineered Quantum Systems, School of Mathematics and Physics, The University of Queensland, QLD 4072, Australiaen
dc.contributor.institutionMaterials Research Institute and School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdomen
dc.contributor.institutionCentre for Engineered Quantum Systems, Australian Institute for Nanoscale Science and Technology, and School of Chemistry, The University of Sydney, NSW 2006, Australiaen
dc.contributor.institutionSPECIFIC IKC, College of Engineering, Swansea University, SA12 7AX, U.K.en
kaust.authorMcCulloch, Iainen
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