Polymer semiconductors incorporating head-to-head linked 4-alkoxy-5-(3-alkylthiophen-2-yl)thiazole

Xin Zhou, Peng Chen, Chang Woo Koh, Sheng Chen, Jianwei Yu, Xianhe Zhang, Yumin Tang, Luca Bianchi, Han Guo, Han Young Woo, Xugang Guo

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

Head-to-head linked bithiophenes with planar backbones hold distinctive advantages for constructing organic semiconductors, such as good solubilizing capability, enabling narrow bandgap, and effective tuning of frontier molecular orbital (FMO) levels using minimal thiophene numbers. In order to realize planar backbone, alkoxy chains are typically installed on thiophene head positions, owing to the small van der Waals radius of oxygen atom and accompanying noncovalent S...O interaction. However, the strong electron donating alkoxy chains on the electron-rich thiophenes lead to elevated FMO levels, which are detrimental to material stability and device performance. Thus, a new design approach is needed to counterbalance the strong electron donating property of alkoxy chains to bring down the FMOs. In this study, we designed and synthesized a new head-to-head linked building block, 4-alkoxy-5-(3-alkylthiophen-2-yl)thiazole (TRTzOR), using an electron-deficient thiazole to replace the electron-rich thiophene. Compared to previously reported 3-alkoxy-3′-alkyl-2,2′-bithiophene (TRTOR), TRTzOR is a weaker electron donor, which considerably lowers FMOs and maintains planar backbone through the noncovalent S...O interaction. The new TRTzOR was copolymerized with benzothiadiazoles with distinct F numbers to yield a series of polymer semiconductors. Compared to TRTOR-based analogous polymers, these TRTzOR-based polymers have broader absorption up to 950 nm with lower-lying FMOs by 0.2-0.3 eV, and blending these polymers with PC71BM leads to polymer solar cells (PSCs) with improved open-circuit voltage (Voc) by ca. 0.1 V and a much smaller energy loss (Eloss) as low as 0.59 eV. These results demonstrate that thiazole substitution is an effective approach to tune FMO levels for realizing higher Vocs in PSCs and the small Eloss renders TRTzOR a promising building block for developing high-performance organic semiconductors.

Original languageEnglish
Pages (from-to)35724-35734
Number of pages11
JournalRSC Advances
Volume8
Issue number62
DOIs
Publication statusPublished - 2018

Bibliographical note

Funding Information:
X. Guo is grateful to the National Science Foundation of China (NSFC, 21774055), Shenzhen Basic Research Fund (JCYJ20170817105905899), Shenzhen Peacock Plan Project (KQTD20140630110339343). H. Guo acknowledges the support from Basic Research Fund of Shenzhen City (JCYJ20160530190226226). X. Zhou is grateful to the Undergraduate Student Innovation Training Program (2016X24) and technical supports provided by High Performance Computer of SUSTech. X. Zhang is grateful to the Undergraduate Student Innovation Training Program (2016X14). H. Y. W. is grateful to the nancial support from the NRF of Korea (2016M1A2A2940911 and 2015M1A2A2057506).

Funding Information:
X. Guo is grateful to the National Science Foundation of China (NSFC, 21774055), Shenzhen Basic Research Fund (JCYJ20170817105905899), Shenzhen Peacock Plan Project (KQTD20140630110339343). H. Guo acknowledges the support from Basic Research Fund of Shenzhen City (JCYJ20160530190226226). X. Zhou is grateful to the Undergraduate Student Innovation Training Program (2016X24) and technical supports provided by High Performance Computer of SUSTech. X. Zhang is grateful to the Undergraduate Student Innovation Training Program (2016X14). H. Y. W. is grateful to the financial support from the NRF of Korea (2016M1A2A2940911 and 2015M1A2A2057506).

Publisher Copyright:
© The Royal Society of Chemistry.

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering

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