The influence of microstructure on charge separation dynamics in organic bulk heterojunction materials for solar cell applications

Handle URI:
http://hdl.handle.net/10754/563183
Title:
The influence of microstructure on charge separation dynamics in organic bulk heterojunction materials for solar cell applications
Authors:
Scarongella, Mariateresa; Paraecattil, Arun Aby; Buchaca-Domingo, Ester; Douglas, Jessica D.; Beaupré, Serge; McCarthy-Ward, Thomas; Heeney, Martin J.; Moser, Jacques Edouard; Leclerc, Mario; Frechet, Jean ( 0000-0001-6419-0163 ) ; Stingelin, Natalie; Banerji, Natalie
Abstract:
Light-induced charge formation is essential for the generation of photocurrent in organic solar cells. In order to gain a better understanding of this complex process, we have investigated the femtosecond dynamics of charge separation upon selective excitation of either the fullerene or the polymer in different bulk heterojunction blends with well-characterized microstructure. Blends of the pBTTT and PBDTTPD polymers with PCBM gave us access to three different scenarios: either a single intermixed phase, an intermixed phase with additional pure PCBM clusters, or a three-phase microstructure of pure polymer aggregates, pure fullerene clusters and intermixed regions. We found that ultrafast charge separation (by electron or hole transfer) occurs predominantly in intermixed regions, while charges are generated more slowly from excitons in pure domains that require diffusion to a charge generation site. The pure domains are helpful to prevent geminate charge recombination, but they must be sufficiently small not to become exciton traps. By varying the polymer packing, backbone planarity and chain length, we have shown that exciton diffusion out of small polymer aggregates in the highly efficient PBDTTPD:PCBM blend occurs within the same chain and is helped by delocalization. This journal is © the Partner Organisations 2014.
KAUST Department:
Chemical Science Program; Physical Sciences and Engineering (PSE) Division
Publisher:
Royal Society of Chemistry (RSC)
Journal:
J. Mater. Chem. A
Issue Date:
2014
DOI:
10.1039/c3ta15112c
Type:
Article
ISSN:
20507488
Sponsors:
N.B. thanks the Swiss National Science Foundation for funding through the Ambizione Fellowship PZ00P2_136853, as well as Prof. Kevin Sivula and his group for assistance regarding sample preparation.
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Chemical Science Program

Full metadata record

DC FieldValue Language
dc.contributor.authorScarongella, Mariateresaen
dc.contributor.authorParaecattil, Arun Abyen
dc.contributor.authorBuchaca-Domingo, Esteren
dc.contributor.authorDouglas, Jessica D.en
dc.contributor.authorBeaupré, Sergeen
dc.contributor.authorMcCarthy-Ward, Thomasen
dc.contributor.authorHeeney, Martin J.en
dc.contributor.authorMoser, Jacques Edouarden
dc.contributor.authorLeclerc, Marioen
dc.contributor.authorFrechet, Jeanen
dc.contributor.authorStingelin, Natalieen
dc.contributor.authorBanerji, Natalieen
dc.date.accessioned2015-08-03T11:37:40Zen
dc.date.available2015-08-03T11:37:40Zen
dc.date.issued2014en
dc.identifier.issn20507488en
dc.identifier.doi10.1039/c3ta15112cen
dc.identifier.urihttp://hdl.handle.net/10754/563183en
dc.description.abstractLight-induced charge formation is essential for the generation of photocurrent in organic solar cells. In order to gain a better understanding of this complex process, we have investigated the femtosecond dynamics of charge separation upon selective excitation of either the fullerene or the polymer in different bulk heterojunction blends with well-characterized microstructure. Blends of the pBTTT and PBDTTPD polymers with PCBM gave us access to three different scenarios: either a single intermixed phase, an intermixed phase with additional pure PCBM clusters, or a three-phase microstructure of pure polymer aggregates, pure fullerene clusters and intermixed regions. We found that ultrafast charge separation (by electron or hole transfer) occurs predominantly in intermixed regions, while charges are generated more slowly from excitons in pure domains that require diffusion to a charge generation site. The pure domains are helpful to prevent geminate charge recombination, but they must be sufficiently small not to become exciton traps. By varying the polymer packing, backbone planarity and chain length, we have shown that exciton diffusion out of small polymer aggregates in the highly efficient PBDTTPD:PCBM blend occurs within the same chain and is helped by delocalization. This journal is © the Partner Organisations 2014.en
dc.description.sponsorshipN.B. thanks the Swiss National Science Foundation for funding through the Ambizione Fellowship PZ00P2_136853, as well as Prof. Kevin Sivula and his group for assistance regarding sample preparation.en
dc.publisherRoyal Society of Chemistry (RSC)en
dc.titleThe influence of microstructure on charge separation dynamics in organic bulk heterojunction materials for solar cell applicationsen
dc.typeArticleen
dc.contributor.departmentChemical Science Programen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.identifier.journalJ. Mater. Chem. Aen
dc.contributor.institutionInstitute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), SB ISIC GR-MO Station 6, CH-1015 Lausanne, Switzerlanden
dc.contributor.institutionCentre for Plastic Electronics, Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdomen
dc.contributor.institutionDepartment of Chemistry, University of California, 727 Latimer Hall, Berkeley, CA 94720-1460, United Statesen
dc.contributor.institutionDepartment of Chemistry, Université Laval, QC G1K 7P4, Canadaen
dc.contributor.institutionCentre for Plastic Electronics, Department of Chemistry, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdomen
kaust.authorFrechet, Jeanen
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