Synthetic principles directing charge transport in low-band-gap dithienosilole-benzothiadiazole copolymers

Handle URI:
http://hdl.handle.net/10754/562197
Title:
Synthetic principles directing charge transport in low-band-gap dithienosilole-benzothiadiazole copolymers
Authors:
Beaujuge, Pierre; Tsao, Hoinok; Hansen, Michael Ryan; Amb, Chad M.; Risko, Chad; Subbiah, Jegadesan; Choudhury, Kaushik Roy; Mavrinskiy, Alexey V.; Pisula, Wojciech; Brédas, Jean Luc; So, Franky; Müllen, Kläus; Reynolds, John R.
Abstract:
Given the fundamental differences in carrier generation and device operation in organic thin-film transistors (OTFTs) and organic photovoltaic (OPV) devices, the material design principles to apply may be expected to differ. In this respect, designing organic semiconductors that perform effectively in multiple device configurations remains a challenge. Following "donor-acceptor" principles, we designed and synthesized an analogous series of solution-processable π-conjugated polymers that combine the electron-rich dithienosilole (DTS) moiety, unsubstituted thiophene spacers, and the electron-deficient core 2,1,3-benzothiadiazole (BTD). Insights into backbone geometry and wave function delocalization as a function of molecular structure are provided by density functional theory (DFT) calculations at the B3LYP/6-31G(d,p) level. Using a combination of X-ray techniques (2D-WAXS and XRD) supported by solid-state NMR (SS-NMR) and atomic force microscopy (AFM), we demonstrate fundamental correlations between the polymer repeat-unit structure, molecular weight distribution, nature of the solubilizing side-chains appended to the backbones, and extent of structural order attainable in p-channel OTFTs. In particular, it is shown that the degree of microstructural order achievable in the self-assembled organic semiconductors increases largely with (i) increasing molecular weight and (ii) appropriate solubilizing-group substitution. The corresponding field-effect hole mobilities are enhanced by several orders of magnitude, reaching up to 0.1 cm 2 V -1 s -1 with the highest molecular weight fraction of the branched alkyl-substituted polymer derivative in this series. This trend is reflected in conventional bulk-heterojunction OPV devices using PC 71BM, whereby the active layers exhibit space-charge-limited (SCL) hole mobilities approaching 10 -3 cm 2 V -1 s -1, and yield improved power conversion efficiencies on the order of 4.6% under AM1.5G solar illumination. Beyond structure-performance correlations, we observe a large dependence of the ionization potentials of the polymers estimated by electrochemical methods on polymer packing, and expect that these empirical results may have important consequences on future material study and device applications. © 2012 American Chemical Society.
KAUST Department:
Chemical Science Program; Physical Sciences and Engineering (PSE) Division; Solar and Photovoltaic Engineering Research Center (SPERC)
Publisher:
American Chemical Society (ACS)
Journal:
Journal of the American Chemical Society
Issue Date:
30-May-2012
DOI:
10.1021/ja301898h
Type:
Article
ISSN:
00027863
Sponsors:
We acknowledge the funding of this work as follows. J.RR: the Air Office of Scientific Research (FA9550-09-1-0320) for new materials development. J.RR. and F.S.: the Office of Naval Research (N00014-11-1-0245) for transport measurements and device construction/testing. J.-L.B.: the Office of Naval Research (N00014-11-1-0211) for computational studies. KM.: the German Science Foundation (Korean-German IR TG), the European Community's Seventh Framework Programme ONE-P (grant agreement no. 212311), DFG Priority Program SPP 1355, DFG MU 334/32-1, DFG Priority Program SPP 1459, and ESF Project GOSPEL (ref no.: 09-EuroGRAPHENE-FP-001) for characterization studies. M.R.H. acknowledges Dr. Robert Graf for helpful discussions and Prof. Hans Wolfgang Spiess for his continued support. P.M.B. acknowledges Dr. Uwe Rietzler and Dr. Rudiger Berger for their support at the AFM facilities of MPIP-Mainz.
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Chemical Science Program; Solar and Photovoltaic Engineering Research Center (SPERC)

Full metadata record

DC FieldValue Language
dc.contributor.authorBeaujuge, Pierreen
dc.contributor.authorTsao, Hoinoken
dc.contributor.authorHansen, Michael Ryanen
dc.contributor.authorAmb, Chad M.en
dc.contributor.authorRisko, Chaden
dc.contributor.authorSubbiah, Jegadesanen
dc.contributor.authorChoudhury, Kaushik Royen
dc.contributor.authorMavrinskiy, Alexey V.en
dc.contributor.authorPisula, Wojciechen
dc.contributor.authorBrédas, Jean Lucen
dc.contributor.authorSo, Frankyen
dc.contributor.authorMüllen, Kläusen
dc.contributor.authorReynolds, John R.en
dc.date.accessioned2015-08-03T09:47:03Zen
dc.date.available2015-08-03T09:47:03Zen
dc.date.issued2012-05-30en
dc.identifier.issn00027863en
dc.identifier.doi10.1021/ja301898hen
dc.identifier.urihttp://hdl.handle.net/10754/562197en
dc.description.abstractGiven the fundamental differences in carrier generation and device operation in organic thin-film transistors (OTFTs) and organic photovoltaic (OPV) devices, the material design principles to apply may be expected to differ. In this respect, designing organic semiconductors that perform effectively in multiple device configurations remains a challenge. Following "donor-acceptor" principles, we designed and synthesized an analogous series of solution-processable π-conjugated polymers that combine the electron-rich dithienosilole (DTS) moiety, unsubstituted thiophene spacers, and the electron-deficient core 2,1,3-benzothiadiazole (BTD). Insights into backbone geometry and wave function delocalization as a function of molecular structure are provided by density functional theory (DFT) calculations at the B3LYP/6-31G(d,p) level. Using a combination of X-ray techniques (2D-WAXS and XRD) supported by solid-state NMR (SS-NMR) and atomic force microscopy (AFM), we demonstrate fundamental correlations between the polymer repeat-unit structure, molecular weight distribution, nature of the solubilizing side-chains appended to the backbones, and extent of structural order attainable in p-channel OTFTs. In particular, it is shown that the degree of microstructural order achievable in the self-assembled organic semiconductors increases largely with (i) increasing molecular weight and (ii) appropriate solubilizing-group substitution. The corresponding field-effect hole mobilities are enhanced by several orders of magnitude, reaching up to 0.1 cm 2 V -1 s -1 with the highest molecular weight fraction of the branched alkyl-substituted polymer derivative in this series. This trend is reflected in conventional bulk-heterojunction OPV devices using PC 71BM, whereby the active layers exhibit space-charge-limited (SCL) hole mobilities approaching 10 -3 cm 2 V -1 s -1, and yield improved power conversion efficiencies on the order of 4.6% under AM1.5G solar illumination. Beyond structure-performance correlations, we observe a large dependence of the ionization potentials of the polymers estimated by electrochemical methods on polymer packing, and expect that these empirical results may have important consequences on future material study and device applications. © 2012 American Chemical Society.en
dc.description.sponsorshipWe acknowledge the funding of this work as follows. J.RR: the Air Office of Scientific Research (FA9550-09-1-0320) for new materials development. J.RR. and F.S.: the Office of Naval Research (N00014-11-1-0245) for transport measurements and device construction/testing. J.-L.B.: the Office of Naval Research (N00014-11-1-0211) for computational studies. KM.: the German Science Foundation (Korean-German IR TG), the European Community's Seventh Framework Programme ONE-P (grant agreement no. 212311), DFG Priority Program SPP 1355, DFG MU 334/32-1, DFG Priority Program SPP 1459, and ESF Project GOSPEL (ref no.: 09-EuroGRAPHENE-FP-001) for characterization studies. M.R.H. acknowledges Dr. Robert Graf for helpful discussions and Prof. Hans Wolfgang Spiess for his continued support. P.M.B. acknowledges Dr. Uwe Rietzler and Dr. Rudiger Berger for their support at the AFM facilities of MPIP-Mainz.en
dc.publisherAmerican Chemical Society (ACS)en
dc.titleSynthetic principles directing charge transport in low-band-gap dithienosilole-benzothiadiazole copolymersen
dc.typeArticleen
dc.contributor.departmentChemical Science Programen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentSolar and Photovoltaic Engineering Research Center (SPERC)en
dc.identifier.journalJournal of the American Chemical Societyen
dc.contributor.institutionDepartment of Chemistry, Center for Macromolecular Science and Engineering, University of Florida, Gainesville, FL 32611, United Statesen
dc.contributor.institutionMax Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germanyen
dc.contributor.institutionDepartment of Materials Science and Engineering, University of Florida, Gainesville, FL 32611, United Statesen
dc.contributor.institutionCenter for Organic Photonics and Electronics, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, United Statesen
kaust.authorBeaujuge, Pierreen
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