On the Role of Contact Resistance and Electrode Modification in Organic Electrochemical Transistors
Hidalgo, Tania C.
Anthopoulos, Thomas D.
KAUST DepartmentPhysical Sciences and Engineering (PSE) Division
Biological and Environmental Sciences and Engineering (BESE) Division
KAUST Solar Center
Biological and Environmental Science and Engineering DivisionKing Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia
Materials Science and Engineering
Embargo End Date2020-07-25
Permanent link to this recordhttp://hdl.handle.net/10754/656276
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AbstractContact resistance is renowned for its unfavorable impact on transistor performance. Despite its notoriety, the nature of contact resistance in organic electrochemical transistors (OECTs) remains unclear. Here, by investigating the role of contact resistance in n-type OECTs, the first demonstration of source/drain-electrode surface modification for achieving state-of-the-art n-type OECTs is reported. Specifically, thiol-based self-assembled monolayers (SAMs), 4-methylbenzenethiol (MBT) and pentafluorobenzenethiol (PFBT), are used to investigate contact resistance in n-type accumulation-mode OECTs made from the hydrophilic copolymer P-90, where the deliberate functionalization of the gold source/drain electrodes decreases and increases the energetic mismatch at the electrode/semiconductor interface, respectively. Although MBT treatment is found to increase the transconductance three-fold, contact resistance is not found to be the dominant factor governing OECT performance. Additional morphology and surface energy investigations show that increased performance comes from SAM-enhanced source/drain electrode surface energy, which improves wetting, semiconductor/metal interface quality, and semiconductor morphology at the electrode and channel. Overall, contact resistance in n-type OECTs is investigated, whilst identifying source/drain electrode treatment as a useful device engineering strategy for achieving state of the art n-type OECTs.
SponsorsS.I., A.F.P., H.F., A.S., G.N., M.G., T.C.H., X.C., I.M., and T.D.A. acknowledge King Abdullah University of Science and Technology (KAUST) for their financial support.