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Title: Variation of the Side Chain Branch Position Leads to Vastly Improved Molecular Weight and OPV Performance in 4,8-dialkoxybenzo[1,2-b:4,5-b′]dithiophene/2,1,3-benzothiadiazole Copolymers

Abstract

Through manipulation of the solubilizing side chains, we were able to dramatically improve the molecular weight ( M w ) of 4,8-dialkoxybenzo[1,2- b :4,5- b ]dithiophene (BDT)/2,1,3-benzothiadiazole (BT) copolymers. When dodecyl side chains ( P1 ) are employed at the 4- and 8-positions of the BDT unit, we obtain a chloroform-soluble copolymer fraction with M w of 6.3 kg/mol. Surprisingly, by moving to the commonly employed 2-ethylhexyl branch ( P2 ), M w decreases to 3.4 kg/mol. This is despite numerous reports that this side chain increases solubility and M w . By moving the ethyl branch in one position relative to the polymer backbone (1-ethylhexyl, P3 ), M w is dramatically increased to 68.8 kg/mol. As a result of this M w increase, the shape of the absorption profile is dramatically altered, with λ max = 637 nm compared with 598 nm for P1 and 579 nm for P2 . The hole mobility as determined by thin film transistor (TFT) measurements is improved from ~ 1 × 10 6  cm 2 /Vs for P1 and P2 to 7 × 10 4  cm 2 /Vs for P3 , while solar cell power conversion efficiency in increased to 2.91 % for P3 relative to 0.31 % and 0.19 % for P1 and P2 , respectively.

Authors:
 [1];  [2];  [1];  [1];  [1];  [1];  [1];  [2];  [1];  [1]
  1. The Department of Physics and the Center for Nanotechnology and Molecular Materials, Wake Forest University, Winston-Salem, NC 27109, USA
  2. The Department of Chemistry, Wake Forest University, Winston-Salem, NC 27109, USA
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1197856
Grant/Contract Number:  
FG02-07ER46428
Resource Type:
Published Article
Journal Name:
Journal of Nanotechnology
Additional Journal Information:
Journal Name: Journal of Nanotechnology Journal Volume: 2011; Journal ID: ISSN 1687-9503
Publisher:
Hindawi Publishing Corporation
Country of Publication:
United Kingdom
Language:
English

Citation Formats

Coffin, Robert C., MacNeill, Christopher M., Peterson, Eric D., Ward, Jeremy W., Owen, Jack W., McLellan, Claire A., Smith, Gregory M., Noftle, Ronald E., Jurchescu, Oana D., and Carroll, David L. Variation of the Side Chain Branch Position Leads to Vastly Improved Molecular Weight and OPV Performance in 4,8-dialkoxybenzo[1,2-b:4,5-b′]dithiophene/2,1,3-benzothiadiazole Copolymers. United Kingdom: N. p., 2011. Web. doi:10.1155/2011/572329.
Coffin, Robert C., MacNeill, Christopher M., Peterson, Eric D., Ward, Jeremy W., Owen, Jack W., McLellan, Claire A., Smith, Gregory M., Noftle, Ronald E., Jurchescu, Oana D., & Carroll, David L. Variation of the Side Chain Branch Position Leads to Vastly Improved Molecular Weight and OPV Performance in 4,8-dialkoxybenzo[1,2-b:4,5-b′]dithiophene/2,1,3-benzothiadiazole Copolymers. United Kingdom. doi:https://doi.org/10.1155/2011/572329
Coffin, Robert C., MacNeill, Christopher M., Peterson, Eric D., Ward, Jeremy W., Owen, Jack W., McLellan, Claire A., Smith, Gregory M., Noftle, Ronald E., Jurchescu, Oana D., and Carroll, David L. Sat . "Variation of the Side Chain Branch Position Leads to Vastly Improved Molecular Weight and OPV Performance in 4,8-dialkoxybenzo[1,2-b:4,5-b′]dithiophene/2,1,3-benzothiadiazole Copolymers". United Kingdom. doi:https://doi.org/10.1155/2011/572329.
@article{osti_1197856,
title = {Variation of the Side Chain Branch Position Leads to Vastly Improved Molecular Weight and OPV Performance in 4,8-dialkoxybenzo[1,2-b:4,5-b′]dithiophene/2,1,3-benzothiadiazole Copolymers},
author = {Coffin, Robert C. and MacNeill, Christopher M. and Peterson, Eric D. and Ward, Jeremy W. and Owen, Jack W. and McLellan, Claire A. and Smith, Gregory M. and Noftle, Ronald E. and Jurchescu, Oana D. and Carroll, David L.},
abstractNote = {Through manipulation of the solubilizing side chains, we were able to dramatically improve the molecular weight ( M w ) of 4,8-dialkoxybenzo[1,2- b :4,5- b ′ ]dithiophene (BDT)/2,1,3-benzothiadiazole (BT) copolymers. When dodecyl side chains ( P1 ) are employed at the 4- and 8-positions of the BDT unit, we obtain a chloroform-soluble copolymer fraction with M w of 6.3 kg/mol. Surprisingly, by moving to the commonly employed 2-ethylhexyl branch ( P2 ), M w decreases to 3.4 kg/mol. This is despite numerous reports that this side chain increases solubility and M w . By moving the ethyl branch in one position relative to the polymer backbone (1-ethylhexyl, P3 ), M w is dramatically increased to 68.8 kg/mol. As a result of this M w increase, the shape of the absorption profile is dramatically altered, with λ max = 637 nm compared with 598 nm for P1 and 579 nm for P2 . The hole mobility as determined by thin film transistor (TFT) measurements is improved from ~ 1 × 10 − 6  cm 2 /Vs for P1 and P2 to 7 × 10 − 4  cm 2 /Vs for P3 , while solar cell power conversion efficiency in increased to 2.91 % for P3 relative to 0.31 % and 0.19 % for P1 and P2 , respectively.},
doi = {10.1155/2011/572329},
journal = {Journal of Nanotechnology},
number = ,
volume = 2011,
place = {United Kingdom},
year = {2011},
month = {1}
}

Journal Article:
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DOI: https://doi.org/10.1155/2011/572329

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Works referenced in this record:

Effects of Postproduction Treatment on Plastic Solar Cells
journal, January 2003

  • Padinger, F.; Rittberger, R. S.; Sariciftci, N. S.
  • Advanced Functional Materials, Vol. 13, Issue 1, p. 85-88
  • DOI: 10.1002/adfm.200390011

Morphology evolution via self-organization and lateral and vertical diffusion in polymer:fullerene solar cell blends
journal, January 2008

  • Campoy-Quiles, Mariano; Ferenczi, Toby; Agostinelli, Tiziano
  • Nature Materials, Vol. 7, Issue 2
  • DOI: 10.1038/nmat2102

Method for increasing the photoconductive response in conjugated polymer/fullerene composites
journal, December 2006

  • Peet, J.; Soci, C.; Coffin, R. C.
  • Applied Physics Letters, Vol. 89, Issue 25
  • DOI: 10.1063/1.2408661

Transition from Solution to the Solid State in Polymer Solar Cells Cast from Mixed Solvents
journal, November 2008

  • Peet, Jeffrey; Cho, Nam Sung; Lee, Sang Kyu
  • Macromolecules, Vol. 41, Issue 22
  • DOI: 10.1021/ma801945h

Conjugated Polymer Photovoltaic Cells
journal, November 2004

  • Coakley, Kevin M.; McGehee, Michael D.
  • Chemistry of Materials, Vol. 16, Issue 23, p. 4533-4542
  • DOI: 10.1021/cm049654n

Indene−C60 Bisadduct: A New Acceptor for High-Performance Polymer Solar Cells
journal, February 2010

  • He, Youjun; Chen, Hsiang-Yu; Hou, Jianhui
  • Journal of the American Chemical Society, Vol. 132, Issue 4, p. 1377-1382
  • DOI: 10.1021/ja908602j

Device annealing effect in organic solar cells with blends of regioregular poly(3-hexylthiophene) and soluble fullerene
journal, February 2005

  • Kim, Youngkyoo; Choulis, Stelios A.; Nelson, Jenny
  • Applied Physics Letters, Vol. 86, Issue 6
  • DOI: 10.1063/1.1861123

Solvent and molecular weight effects on fluorescence emission of MEH-PPV
journal, January 2005


A Thieno[3,4- c ]pyrrole-4,6-dione-Based Copolymer for Efficient Solar Cells
journal, April 2010

  • Zou, Yingping; Najari, Ahmed; Berrouard, Philippe
  • Journal of the American Chemical Society, Vol. 132, Issue 15
  • DOI: 10.1021/ja101888b

Microwave-Assisted Preparation of Semiconducting Polymers
journal, February 2007

  • Galbrecht, Frank; Bünnagel, Torsten W.; Scherf, Ullrich
  • Macromolecular Rapid Communications, Vol. 28, Issue 4
  • DOI: 10.1002/marc.200600778

Synthesis of a Low Band Gap Polymer and Its Application in Highly Efficient Polymer Solar Cells
journal, November 2009

  • Hou, Jianhui; Chen, Hsiang-Yu; Zhang, Shaoqing
  • Journal of the American Chemical Society, Vol. 131, Issue 43
  • DOI: 10.1021/ja9064975

Polymer solar cells with enhanced open-circuit voltage and efficiency
journal, November 2009

  • Chen, Hsiang-Yu; Hou, Jianhui; Zhang, Shaoqing
  • Nature Photonics, Vol. 3, Issue 11, p. 649-653
  • DOI: 10.1038/nphoton.2009.192

Semiconducting Polymers via Microwave-Assisted Suzuki and Stille Cross-Coupling Reactions
journal, April 2004

  • Nehls, B. S.; Asawapirom, U.; Füldner, S.
  • Advanced Functional Materials, Vol. 14, Issue 4
  • DOI: 10.1002/adfm.200400010

Dependence of Regioregular Poly(3-hexylthiophene) Film Morphology and Field-Effect Mobility on Molecular Weight
journal, April 2005

  • Kline, R. Joseph; McGehee, Michael D.; Kadnikova, Ekaterina N.
  • Macromolecules, Vol. 38, Issue 8, p. 3312-3319
  • DOI: 10.1021/ma047415f

Conjugated Polymer-Based Organic Solar Cells
journal, April 2007

  • Günes, Serap; Neugebauer, Helmut; Sariciftci, Niyazi Serdar
  • Chemical Reviews, Vol. 107, Issue 4, p. 1324-1338
  • DOI: 10.1021/cr050149z

Polymer–Fullerene Composite Solar Cells
journal, January 2008

  • Thompson, Barry C.; Fréchet, Jean M. J.
  • Angewandte Chemie International Edition, Vol. 47, Issue 1, p. 58-77
  • DOI: 10.1002/anie.200702506

Synthesis of Conjugated Polymers for Organic Solar Cell Applications
journal, November 2009

  • Cheng, Yen-Ju; Yang, Sheng-Hsiung; Hsu, Chain-Shu
  • Chemical Reviews, Vol. 109, Issue 11
  • DOI: 10.1021/cr900182s

Polymer solar cells: Recent development and possible routes for improvement in the performance
journal, February 2010


For the Bright Future-Bulk Heterojunction Polymer Solar Cells with Power Conversion Efficiency of 7.4%
journal, May 2010

  • Liang, Yongye; Xu, Zheng; Xia, Jiangbin
  • Advanced Materials, Vol. 22, Issue 20, p. E135-E138
  • DOI: 10.1002/adma.200903528

Bandgap and Molecular Energy Level Control of Conjugated Polymer Photovoltaic Materials Based on Benzo[1,2- b :4,5- b ′]dithiophene
journal, August 2008

  • Hou, Jianhui; Park, Mi-Hyae; Zhang, Shaoqing
  • Macromolecules, Vol. 41, Issue 16
  • DOI: 10.1021/ma800820r

Efficiency enhancement in low-bandgap polymer solar cells by processing with alkane dithiols
journal, May 2007

  • Peet, J.; Kim, J. Y.; Coates, N. E.
  • Nature Materials, Vol. 6, Issue 7, p. 497-500
  • DOI: 10.1038/nmat1928

Efficient Tandem Polymer Solar Cells Fabricated by All-Solution Processing
journal, July 2007

  • Kim, Jin Young; Lee, Kwanghee; Coates, Nelson E.
  • Science, Vol. 317, Issue 5835, p. 222-225
  • DOI: 10.1126/science.1141711

Processing Additives for Improved Efficiency from Bulk Heterojunction Solar Cells
journal, March 2008

  • Lee, Jae Kwan; Ma, Wan Li; Brabec, Christoph J.
  • Journal of the American Chemical Society, Vol. 130, Issue 11
  • DOI: 10.1021/ja710079w

Bromination of 2,1,3-benzothiadiazoles
journal, June 1970

  • Pilgram, Kurt; Zupan, Mike; Skiles, Richard
  • Journal of Heterocyclic Chemistry, Vol. 7, Issue 3
  • DOI: 10.1002/jhet.5570070324

Highly Efficient Solar Cell Polymers Developed via Fine-Tuning of Structural and Electronic Properties
journal, June 2009

  • Liang, Yongye; Feng, Danqin; Wu, Yue
  • Journal of the American Chemical Society, Vol. 131, Issue 22, p. 7792-7799
  • DOI: 10.1021/ja901545q

Fullerene Bisadducts for Enhanced Open-Circuit Voltages and Efficiencies in Polymer Solar Cells
journal, June 2008

  • Lenes, Martijn; Wetzelaer, Gert-Jan A. H.; Kooistra, Floris B.
  • Advanced Materials, Vol. 20, Issue 11, p. 2116-2119
  • DOI: 10.1002/adma.200702438

Progress in polymer solar cell
journal, January 2007


Nickel(0)-Mediated Coupling Polymerizations via Microwave-Assisted Chemistry
journal, August 2002


Effect of Processing Additive on the Nanomorphology of a Bulk Heterojunction Material
journal, October 2010

  • Moon, Ji Sun; Takacs, Christopher J.; Cho, Shinuk
  • Nano Letters, Vol. 10, Issue 10
  • DOI: 10.1021/nl101923m

Enhanced Photovoltaic Performance of Low-Bandgap Polymers with Deep LUMO Levels
journal, September 2010

  • Zhou, Huaxing; Yang, Liqiang; Price, Samuel C.
  • Angewandte Chemie International Edition, Vol. 49, Issue 43, p. 7992-7995
  • DOI: 10.1002/anie.201003357

Synthetic Control of Structural Order in N-Alkylthieno[3,4-c]pyrrole-4,6-dione-Based Polymers for Efficient Solar Cells
journal, June 2010

  • Piliego, Claudia; Holcombe, Thomas W.; Douglas, Jessica D.
  • Journal of the American Chemical Society, Vol. 132, Issue 22, p. 7595-7597
  • DOI: 10.1021/ja103275u

Streamlined microwave-assisted preparation of narrow-bandgap conjugated polymers for high-performance bulk heterojunction solar cells
journal, October 2009

  • Coffin, Robert C.; Peet, Jeff; Rogers, James
  • Nature Chemistry, Vol. 1, Issue 8
  • DOI: 10.1038/nchem.403