Sub-ns triplet state formation by non-geminate recombination in PSBTBT:PC 70 BM and PCPDTBT:PC 60 BM organic solar cells

Handle URI:
http://hdl.handle.net/10754/552986
Title:
Sub-ns triplet state formation by non-geminate recombination in PSBTBT:PC 70 BM and PCPDTBT:PC 60 BM organic solar cells
Authors:
Etzold, Fabian; Howard, Ian A.; Forler, Nina; Melnyk, Anton; Andrienko, Denis; Hansen, Michael Ryan; Laquai, Frederic ( 0000-0002-5887-6158 )
Abstract:
The solid-state morphology and photo-generated charge carrier dynamics in low-bandgap polymer:fullerene bulk heterojunction photovoltaic blends using the donor–acceptor type copolymers PCPDTBT or its silicon-substituted analogue PSBTBT as donors are compared by two-dimensional (2D) solid-state nuclear magnetic resonance (NMR) and femto-to microsecond broadband Vis-NIR transient absorption (TA) pump–probe spectroscopy. The 2D solid-state NMR experiments demonstrate that the film morphology of PCPDTBT:PC60BM blends processed with additives such as octanedithiol (ODT) are similar to those of PSBTBT:PC60BM blends in terms of crystallinity, phase segregation, and interfacial contacts. The TA experiments and analysis of the TA data by multivariate curve resolution (MCR) reveal that after exciton dissociation and free charge formation, fast sub-nanosecond non-geminate recombination occurs which leads to a substantial population of the polymer's triplet state. The extent to which triplet states are formed depends on the initial concentration of free charges, which itself is controlled by the microstructure of the blend, especially in case of PCPDTBT:PC60BM. Interestingly, PSBTBT:PC70BM blends show a higher charge generation efficiency, but less triplet state formation at similar free charge carrier concentrations. This indicates that the solid-state morphology and interfacial structures of PSBTBT:PC70BM blends reduces non-geminate recombination, leading to superior device performance compared to optimized PCPDTBT:PC60BM blends.
KAUST Department:
Physical Sciences and Engineering (PSE) Division; Solar and Photovoltaic Engineering Research Center; Materials Science and Engineering Program
Citation:
Sub-ns triplet state formation by non-geminate recombination in PSBTBT:PC 70 BM and PCPDTBT:PC 60 BM organic solar cells 2015, 8 (5):1511 Energy Environ. Sci.
Journal:
Energy Environ. Sci.
Issue Date:
2-Mar-2015
DOI:
10.1039/C4EE03630A
Type:
Article
ISSN:
1754-5692; 1754-5706
Additional Links:
http://xlink.rsc.org/?DOI=C4EE03630A
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.authorEtzold, Fabianen
dc.contributor.authorHoward, Ian A.en
dc.contributor.authorForler, Ninaen
dc.contributor.authorMelnyk, Antonen
dc.contributor.authorAndrienko, Denisen
dc.contributor.authorHansen, Michael Ryanen
dc.contributor.authorLaquai, Fredericen
dc.date.accessioned2015-05-17T20:35:36Zen
dc.date.available2015-05-17T20:35:36Zen
dc.date.issued2015-03-02en
dc.identifier.citationSub-ns triplet state formation by non-geminate recombination in PSBTBT:PC 70 BM and PCPDTBT:PC 60 BM organic solar cells 2015, 8 (5):1511 Energy Environ. Sci.en
dc.identifier.issn1754-5692en
dc.identifier.issn1754-5706en
dc.identifier.doi10.1039/C4EE03630Aen
dc.identifier.urihttp://hdl.handle.net/10754/552986en
dc.description.abstractThe solid-state morphology and photo-generated charge carrier dynamics in low-bandgap polymer:fullerene bulk heterojunction photovoltaic blends using the donor–acceptor type copolymers PCPDTBT or its silicon-substituted analogue PSBTBT as donors are compared by two-dimensional (2D) solid-state nuclear magnetic resonance (NMR) and femto-to microsecond broadband Vis-NIR transient absorption (TA) pump–probe spectroscopy. The 2D solid-state NMR experiments demonstrate that the film morphology of PCPDTBT:PC60BM blends processed with additives such as octanedithiol (ODT) are similar to those of PSBTBT:PC60BM blends in terms of crystallinity, phase segregation, and interfacial contacts. The TA experiments and analysis of the TA data by multivariate curve resolution (MCR) reveal that after exciton dissociation and free charge formation, fast sub-nanosecond non-geminate recombination occurs which leads to a substantial population of the polymer's triplet state. The extent to which triplet states are formed depends on the initial concentration of free charges, which itself is controlled by the microstructure of the blend, especially in case of PCPDTBT:PC60BM. Interestingly, PSBTBT:PC70BM blends show a higher charge generation efficiency, but less triplet state formation at similar free charge carrier concentrations. This indicates that the solid-state morphology and interfacial structures of PSBTBT:PC70BM blends reduces non-geminate recombination, leading to superior device performance compared to optimized PCPDTBT:PC60BM blends.en
dc.relation.urlhttp://xlink.rsc.org/?DOI=C4EE03630Aen
dc.rightsArchived with thanks to Energy Environ. Sci. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. http://creativecommons.org/licenses/by/3.0/en
dc.titleSub-ns triplet state formation by non-geminate recombination in PSBTBT:PC 70 BM and PCPDTBT:PC 60 BM organic solar cellsen
dc.typeArticleen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentSolar and Photovoltaic Engineering Research Centeren
dc.contributor.departmentMaterials Science and Engineering Programen
dc.identifier.journalEnergy Environ. Sci.en
dc.eprint.versionPublisher's Version/PDFen
dc.contributor.institutionMax Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germanyen
dc.contributor.institutionInterdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmarken
kaust.authorLaquai, Fredericen
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