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Author ORCID Identifier
Date Available
4-21-2028
Year of Publication
2026
Document Type
Master's Thesis
Degree Name
Master of Science (MS)
College
Engineering
Department/School/Program
Electrical and Computer Engineering
Faculty
Alexandra F Paterson
Faculty
Daniel Lau
Abstract
Organic electrochemical transistors (OECTs) use organic mixed ionic electronic conductors (OMIECs) as the active material because of their unique ability to transport both electronic and ionic charge carriers and operate in an aqueous environment. Moreover, OECTs provide a wide range of applications, starting from biosensors, energy storage, and neuromorphic computing. In spite of the significant prospect of OECTs, there is a critical gap in understanding the fundamental properties during device operation, including charge transport, charge injection mechanism, contact geometry, and electrolyte solvent properties.
In this study, low-temperature measurement of OECT device parameters such as mobility, contact resistance, and activation energy challenges the existing assumption of charge transport physics in heavily doped OMIECs. Mobility-temperature trend indicates multiple trap and release as the dominant charge transport mechanism, while contact resistance-temperature trend indicates tunneling as the dominant charge injection mechanism. Next, conductance-temperature data show a reversible insulator-to-metal transition at high carrier densities, which is observed here for the first time in OMIECs and OECTs. Furthermore, a deviation from the gradual channel approximation model is observed due to the presence of edge effects at narrower channels and voltage-dependent channel resistance.
Overall, this work provides a combined framework that shows how the OECT performance is influenced by the complex interplay of electronic-ionic interactions, carrier density, device geometry, and electrolyte solvent. This analysis paves a clear path for future design of high-performance OECT devices with proper estimation of device parameters and a deeper understanding of device physics.
Digital Object Identifier (DOI)
https://doi.org/10.13023/etd.2026.90
Archival?
Archival
Funding Information
This study was supported by the National Science Foundation's Faculty Early Career Development Award (no.: 2441261) in 2025 and the National Science Foundation's Mathematical and Physical Sciences Program (no.:2349830) in 2024.
Recommended Citation
Tahsin, Samiha, "IONIC-ELECTRONIC INTERACTIONS GOVERNING CHARGE TRANSPORT AND PERFORMANCE IN ORGANIC ELECTROCHEMICAL TRANSISTORS" (2026). Theses and Dissertations--Electrical and Computer Engineering. 230.
https://uknowledge.uky.edu/ece_etds/230
Included in
Electronic Devices and Semiconductor Manufacturing Commons, Polymer and Organic Materials Commons
