Abstract
Molecular doping of organic semiconductors is often used to enhance their charge transport characteristics. Despite its success, however, most studies to date concern p-doping with considerably fewer reports involving n-dopants. Here, n-doping of organic thin-film transistors (OTFTs) based on several non-fullerene acceptor (NFA) molecules using the recently developed diquat (DQ) as a soluble molecular dopant is reported. The low ionization potential of DQ facilitates efficient electron transfer and subsequent n-doping of the NFAs, resulting in a consistent increase in the electron field-effect mobility. Solution-processed BTP-eC9 and N3-based OTFTs exhibit significant increase in the electron mobility upon DQ doping, with values increasing from 0.02 to 0.17 cm2 V–1 s–1 and from 0.2 to 0.57 cm2 V–1 s–1, respectively. A remarkable electron mobility of >1 cm2 V–1 s–1 is achieved for O-IDTBR transistors upon optimal doping with DQ. The enhanced performance originates primarily from synergistic effects on electronic transport and changes in morphology, including: i) significant reduction of contact resistances, ii) formation of larger crystalline domains, iii) change of preferred crystal orientation, and iv) alteration in molecular packing motif. This work demonstrates the universality of DQ as an electronic additive for improving electron transport in OTFTs.
Original language | English (US) |
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Pages (from-to) | 2202954 |
Journal | Advanced Functional Materials |
DOIs | |
State | Published - Jul 15 2022 |
Bibliographical note
KAUST Repository Item: Exported on 2022-09-14Acknowledged KAUST grant number(s): OSR-2018-CARF/CCF-3079, OSR-2019-CRG8-4095
Acknowledgements: This publication was based upon work supported by the King Abdullah University of Science and Technology (KAUST) Office of Sponsored Research (OSR) under Award No: OSR-2018-CARF/CCF-3079, and OSR-2019-CRG8-4095. GIWAXS experiments were performed at BL11 NCD-SWEET beamline at ALBA Synchrotron (Spain) with the collaboration of ALBA staff.
ASJC Scopus subject areas
- Biomaterials
- Electrochemistry
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics