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Title: Random Copolymers Allow Control of Crystallization and Microphase Separation in Fully Conjugated Block Copolymers

Abstract

Thin films of fully conjugated donor–acceptor block copolymers composed of an electron donating block and an electron accepting block can be used as single component photoactive layers in organic photovoltaic (OPV) devices. In order to realize their full potential, control over microphase separation and thin-film morphology are critical. In conjugated block copolymer systems where one or more blocks can crystallize, the morphological evolution is governed by the competition between microphase separation and crystallization. In this work, we control crystallization of fully conjugated block copolymers with a random copolymer block. Additionally, we suppress the crystal packing of poly(3-hexylthiophene-2,5-diyl) (P3HT) through the insertion of a small number of 3-octylthiophene (3OT) units within the chains, yielding poly(3-hexylthiophene-2,5-diyl- random-3-octylthiophene-2,5-diyl) (P[3HT- r-3OT]). Furthermore, while crystallization of P3HT dominates the morphology and prevents microphase separation in poly(3-hexylthiophene-2,5-diyl)- block-poly((9,9-dioctylfluorene-2,7-diyl)- alt-(4,7-di(thiophene-2-yl)-2,1,3-benzothiadiazole)-5',5"-diyl) (P3HT- b-PFTBT), modest levels of 3OT suppress crystallization in P[3HT- r-3OT]- b-PFTBT, and permit microphase separation. Thus, we demonstrate that incorporating a random copolymer into a donor–acceptor block copolymer can increase control over microphase separation and lead to enhanced performance in OPV devices.

Authors:
 [1];  [2];  [3]; ORCiD logo [2];  [2];  [4];  [4]; ORCiD logo [3]; ORCiD logo [2]; ORCiD logo [5]
  1. Pennsylvania State Univ., University Park, PA (United States); New Mexico Tech, Socorro, NM (United States)
  2. Pennsylvania State Univ., University Park, PA (United States)
  3. Univ. of Tennessee, Knoxville, TN (United States)
  4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS)
  5. Pennsylvania State Univ., University Park, PA (United States); Pennsylvania State Univ., University Park, PA (United States). Materials Research Inst.
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES); US Office of Naval Research (ONR); National Science Foundation (NSF)
OSTI Identifier:
1656476
Grant/Contract Number:  
AC02-05CH11231; N000141410532; EPS 1004083; EPS 1512221
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Macromolecules
Additional Journal Information:
Journal Volume: 51; Journal Issue: 21; Journal ID: ISSN 0024-9297
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
Thin films; crystallization; microphase; organic polymers; copolymers

Citation Formats

Lee, Youngmin, Aplan, Melissa P., Seibers, Zach D., Xie, Renxuan, Culp, Tyler E., Wang, Cheng, Hexemer, Alexander, Kilbey, S. Michael, Wang, Qing, and Gomez, Enrique D. Random Copolymers Allow Control of Crystallization and Microphase Separation in Fully Conjugated Block Copolymers. United States: N. p., 2018. Web. doi:10.1021/acs.macromol.8b01859.
Lee, Youngmin, Aplan, Melissa P., Seibers, Zach D., Xie, Renxuan, Culp, Tyler E., Wang, Cheng, Hexemer, Alexander, Kilbey, S. Michael, Wang, Qing, & Gomez, Enrique D. Random Copolymers Allow Control of Crystallization and Microphase Separation in Fully Conjugated Block Copolymers. United States. doi:10.1021/acs.macromol.8b01859.
Lee, Youngmin, Aplan, Melissa P., Seibers, Zach D., Xie, Renxuan, Culp, Tyler E., Wang, Cheng, Hexemer, Alexander, Kilbey, S. Michael, Wang, Qing, and Gomez, Enrique D. Mon . "Random Copolymers Allow Control of Crystallization and Microphase Separation in Fully Conjugated Block Copolymers". United States. doi:10.1021/acs.macromol.8b01859. https://www.osti.gov/servlets/purl/1656476.
@article{osti_1656476,
title = {Random Copolymers Allow Control of Crystallization and Microphase Separation in Fully Conjugated Block Copolymers},
author = {Lee, Youngmin and Aplan, Melissa P. and Seibers, Zach D. and Xie, Renxuan and Culp, Tyler E. and Wang, Cheng and Hexemer, Alexander and Kilbey, S. Michael and Wang, Qing and Gomez, Enrique D.},
abstractNote = {Thin films of fully conjugated donor–acceptor block copolymers composed of an electron donating block and an electron accepting block can be used as single component photoactive layers in organic photovoltaic (OPV) devices. In order to realize their full potential, control over microphase separation and thin-film morphology are critical. In conjugated block copolymer systems where one or more blocks can crystallize, the morphological evolution is governed by the competition between microphase separation and crystallization. In this work, we control crystallization of fully conjugated block copolymers with a random copolymer block. Additionally, we suppress the crystal packing of poly(3-hexylthiophene-2,5-diyl) (P3HT) through the insertion of a small number of 3-octylthiophene (3OT) units within the chains, yielding poly(3-hexylthiophene-2,5-diyl-random-3-octylthiophene-2,5-diyl) (P[3HT-r-3OT]). Furthermore, while crystallization of P3HT dominates the morphology and prevents microphase separation in poly(3-hexylthiophene-2,5-diyl)-block-poly((9,9-dioctylfluorene-2,7-diyl)-alt-(4,7-di(thiophene-2-yl)-2,1,3-benzothiadiazole)-5',5"-diyl) (P3HT-b-PFTBT), modest levels of 3OT suppress crystallization in P[3HT-r-3OT]-b-PFTBT, and permit microphase separation. Thus, we demonstrate that incorporating a random copolymer into a donor–acceptor block copolymer can increase control over microphase separation and lead to enhanced performance in OPV devices.},
doi = {10.1021/acs.macromol.8b01859},
journal = {Macromolecules},
issn = {0024-9297},
number = 21,
volume = 51,
place = {United States},
year = {2018},
month = {10}
}

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