A Universal Method for Achieving Ultra‐Low Contact Resistances in Organic Electrochemical Transistors

Abstract Organic ElectroChemical Transistors (OECTs) are intensively studied for enabling their use in organic bioelectronics, neuromorphic systems, and biosensors. Beyond device geometry, reaching optimal operation of organic electronic circuits requires the optimization of the physico‐chemical pro...

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Main Authors: Luis‐Abraham Lozano‐Hernández, Patrice Rannou, Yvan Bonnassieux, Sébastien Sanaur
Format: Article
Language:English
Published: Wiley-VCH 2025-08-01
Series:Advanced Materials Interfaces
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Online Access:https://doi.org/10.1002/admi.202500208
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author Luis‐Abraham Lozano‐Hernández
Patrice Rannou
Yvan Bonnassieux
Sébastien Sanaur
author_facet Luis‐Abraham Lozano‐Hernández
Patrice Rannou
Yvan Bonnassieux
Sébastien Sanaur
author_sort Luis‐Abraham Lozano‐Hernández
collection DOAJ
description Abstract Organic ElectroChemical Transistors (OECTs) are intensively studied for enabling their use in organic bioelectronics, neuromorphic systems, and biosensors. Beyond device geometry, reaching optimal operation of organic electronic circuits requires the optimization of the physico‐chemical properties of the channel. Toward this end, the effects of a “bulk” doping of the channel material and its influence on the contact resistance (RC) at the interface between a Polymeric Mixed Ionic‐Electronic conductors (PMIECs) and the Source (S) and Drain (D) electrodes are presented. An easy‐to‐implement method to achieve ultra‐low contact resistances in OECTs is introduced. By incorporation of LiTFSI, a 4x transconductance improvement is achieved, and a decrease of RC by a factor of ≈2 and ≈40 has been observed for p‐type or n‐type PMIECs, respectively. It reaches an unprecedented width‐normalized contact resistance value as low as 1 Ohm.cm with the p(g2T‐T) polymer. The formation of very localized domains in the polymeric matrix in the vicinity of the electrodes, as a result of the reduction of TFSIˉ anions, which modulates the energy barrier at the S/D interface, is suggested here. Furthermore, both p(g2T‐T) and p(gNDI‐gT2) polymers exhibit low water uptake with minute amounts of LiTFSI. Worth noticing, doped p(g2T‐T) preserves its volumetric capacitance and demonstrates an exceptional long‐term stability. Finally, a universal strategy to fine‐tune OECT performances, drawing prospects for implementing next‐generation applications in organic bioelectronics and neuromorphics, is proposed.
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spelling doaj-art-b50ea8a72ff24c2787c96741f2d7358f2025-08-25T08:06:18ZengWiley-VCHAdvanced Materials Interfaces2196-73502025-08-011216n/an/a10.1002/admi.202500208A Universal Method for Achieving Ultra‐Low Contact Resistances in Organic Electrochemical TransistorsLuis‐Abraham Lozano‐Hernández0Patrice Rannou1Yvan Bonnassieux2Sébastien Sanaur3Mines Saint‐Etienne Department of Flexible Electronics Centre Microélectronique de Provence Gardanne F‐13541 FranceUniv. Grenoble Alpes, Univ. Savoie Mont Blanc, Grenoble INP, LEPMI CNRS Grenoble 38000 FranceLPICM (UMR 7647 CNRS) École Polytechnique – Institut Polytechnique de Paris Route de Saclay Palaiseau 91128 FranceMines Saint‐Etienne Department of Flexible Electronics Centre Microélectronique de Provence Gardanne F‐13541 FranceAbstract Organic ElectroChemical Transistors (OECTs) are intensively studied for enabling their use in organic bioelectronics, neuromorphic systems, and biosensors. Beyond device geometry, reaching optimal operation of organic electronic circuits requires the optimization of the physico‐chemical properties of the channel. Toward this end, the effects of a “bulk” doping of the channel material and its influence on the contact resistance (RC) at the interface between a Polymeric Mixed Ionic‐Electronic conductors (PMIECs) and the Source (S) and Drain (D) electrodes are presented. An easy‐to‐implement method to achieve ultra‐low contact resistances in OECTs is introduced. By incorporation of LiTFSI, a 4x transconductance improvement is achieved, and a decrease of RC by a factor of ≈2 and ≈40 has been observed for p‐type or n‐type PMIECs, respectively. It reaches an unprecedented width‐normalized contact resistance value as low as 1 Ohm.cm with the p(g2T‐T) polymer. The formation of very localized domains in the polymeric matrix in the vicinity of the electrodes, as a result of the reduction of TFSIˉ anions, which modulates the energy barrier at the S/D interface, is suggested here. Furthermore, both p(g2T‐T) and p(gNDI‐gT2) polymers exhibit low water uptake with minute amounts of LiTFSI. Worth noticing, doped p(g2T‐T) preserves its volumetric capacitance and demonstrates an exceptional long‐term stability. Finally, a universal strategy to fine‐tune OECT performances, drawing prospects for implementing next‐generation applications in organic bioelectronics and neuromorphics, is proposed.https://doi.org/10.1002/admi.202500208contact resistanceselectrochemical dopingorganic electrochemical transistorsorganic mixed ionic‐electronic conductorssolvation
spellingShingle Luis‐Abraham Lozano‐Hernández
Patrice Rannou
Yvan Bonnassieux
Sébastien Sanaur
A Universal Method for Achieving Ultra‐Low Contact Resistances in Organic Electrochemical Transistors
Advanced Materials Interfaces
contact resistances
electrochemical doping
organic electrochemical transistors
organic mixed ionic‐electronic conductors
solvation
title A Universal Method for Achieving Ultra‐Low Contact Resistances in Organic Electrochemical Transistors
title_full A Universal Method for Achieving Ultra‐Low Contact Resistances in Organic Electrochemical Transistors
title_fullStr A Universal Method for Achieving Ultra‐Low Contact Resistances in Organic Electrochemical Transistors
title_full_unstemmed A Universal Method for Achieving Ultra‐Low Contact Resistances in Organic Electrochemical Transistors
title_short A Universal Method for Achieving Ultra‐Low Contact Resistances in Organic Electrochemical Transistors
title_sort universal method for achieving ultra low contact resistances in organic electrochemical transistors
topic contact resistances
electrochemical doping
organic electrochemical transistors
organic mixed ionic‐electronic conductors
solvation
url https://doi.org/10.1002/admi.202500208
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