TY - JOUR
T1 - On the Role of Contact Resistance and Electrode Modification in Organic Electrochemical Transistors
AU - Paterson, Alexandra F.
AU - Faber, Hendrik
AU - Savva, Achilleas
AU - Nikiforidis, Georgios
AU - Gedda, Murali
AU - Hidalgo, Tania C.
AU - Chen, Xingxing
AU - McCulloch, Iain
AU - Anthopoulos, Thomas D.
AU - Inal, Sahika
N1 - Publisher Copyright:
© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
PY - 2019/9/1
Y1 - 2019/9/1
N2 - Contact 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.
AB - Contact 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.
KW - contact resistance
KW - electrode modification
KW - morphology/organic semiconductors
KW - organic electrochemical transistors
KW - self-assembled monolayers
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U2 - 10.1002/adma.201902291
DO - 10.1002/adma.201902291
M3 - Article
C2 - 31343087
AN - SCOPUS:85071997319
SN - 0935-9648
VL - 31
JO - Advanced Materials
JF - Advanced Materials
IS - 37
M1 - 1902291
ER -