Title: Backbone-driven host–dopant miscibility modulates molecular doping in NDI conjugated polymers

Abstract

Molecular doping is the key to enabling organic electronic devices, however, the design strategies to maximize doping efficiency demands further clarity and comprehension. Previous reports focus on the effect of the side chains, but the role of the backbone is still not well understood. In this study, we synthesize a series of NDI-based copolymers with bithiophene, vinylene, and acetylenic moieties (P1G, P2G, and P3G, respectively), all containing branched triethylene glycol side chains. Using computational and experimental methods, we explore the impact of the conjugated backbone using three key parameters for doping in organic semiconductors: energy levels, microstructure, and miscibility. Our experimental results show that P1G undergoes the most efficient n-type doping owed primarily to its higher dipole moment, and better host–dopant miscibility with N-DMBI. In contrast, P2G and P3G possess more planar backbones than P1G, but the lack of long-range order, and poor host–dopant miscibility limit their doping efficiency. Our data suggest that backbone planarity alone is not enough to maximize the electrical conductivity (σ) of n-type doped organic semiconductors, and that backbone polarity also plays an important role in enhancing σ via host–dopant miscibility. Finally, the thermoelectric properties of doped P1G exhibit a power factor of 0.077 μW m^-1more » K^-2, and ultra-low in-plane thermal conductivity of 0.13 W m^-1K^-1 at 5 mol% of N-DMBI, which is among the lowest thermal conductivity values reported for n-type doped conjugated polymers.« less

Authors:

Rosas Villalva, Diego  ^[1];

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• Search DOE PAGES for ORCID "0000-0001-7165-5256"

Singh, Saumya ^[2]; Galuska, Luke A.  ^[3];

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• Search DOE PAGES for ORCID "0000-0002-0101-8507"

Sharma, Anirudh  ^[1];

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• Search DOE PAGES for ORCID "0000-0003-4841-0108"

Han, Jianhua ^[1]; Liu, Jian ^[4]; Haque, Md Azimul  ^[1];

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• Search DOE PAGES for ORCID "0000-0003-3528-0674"

Jang, Soyeong ^[1]; Emwas, Abdul Hamid ^[5]; Koster, L. Jan Anton  ^[4];

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• Search DOE PAGES for ORCID "0000-0002-6558-5295"

Gu, Xiaodan  ^[3];

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• Search DOE PAGES for ORCID "0000-0002-1123-3673"

Schroeder, Bob C.  ^[2];

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• Search DOE PAGES for ORCID "0000-0002-9793-631X"

Baran, Derya  ^[1]

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• Search DOE PAGES for ORCID "0000-0003-2196-8187"

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+ Show Author Affiliations

1. King Abdullah University of Science and Technology (KAUST), Physical Sciences and Engineering Division (PSE), KAUST Solar Center (KSC), Thuwal 23955, Saudi Arabia
2. Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
3. School of Polymer Science and Engineering, University of Southern Mississippi, Hattiesburg, MS, 39406, USA
4. Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
5. King Abdullah University of Science and Technology (KAUST), Core Labs, Thuwal 23955, Saudi Arabia

Publication Date:

Tue Jan 04 00:00:00 EST 2022

Research Org.:

University of Southern Mississippi, Hattiesburg, MS (United States)

Sponsoring Org.:

USDOE Office of Science (SC); British Council Newton Fund; King Abdullah University of Science and Technology (KAUST); Engineering and Physical Sciences Research Council (EPSRC); Netherlands Organization for Scientific Research (NWO)

OSTI Identifier:

1836602

Alternate Identifier(s):

OSTI ID: 1904251

Grant/Contract Number:  

SC0022050; OSR-CRG2018-3737; MR/S031952/1; EP/P007767/1; VIDI 13476

Resource Type:

Published Article

Journal Name:

Materials Horizons

Additional Journal Information:

Journal Name: Materials Horizons Journal Volume: 9 Journal Issue: 1; Journal ID: ISSN 2051-6347

Publisher:

Royal Society of Chemistry (RSC)

Country of Publication:

United Kingdom

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE