Author ORCID Identifier
Date Available
12-19-2025
Year of Publication
2025
Document Type
Doctoral Dissertation
Degree Name
Doctor of Philosophy (PhD)
College
Engineering
Department/School/Program
Materials Science and Engineering
Faculty
Alexandra Paterson
Faculty
Matthew Beck
Abstract
Organic mixed ionic-electronic conductors (OMIECs) are soft materials that transport ionic and electronic charges. OMIECs are the central electrical component for organic electrochemical transistors (OECTs), which possess the unique ability to operate in aqueous environments and have profound signal amplification capabilities. OECTs have good prospects for next generation technologies such as biosensing, power adaptive computing, and energy storage. Despite this promising potential, OMIECs and OECTs currently struggle to meet the performance needed to function within this application space, facing limitations such as low carrier mobility, threshold voltage tuneability, and stability.
Here, these challenges are addressed by using molecular doping strategies to tailor OECT performance and stability, while also investigating the fundamental mechanisms underlying device operation. First, tetrabutylammonium hydroxide (TBA-OH) is identified as a new n-type dopant for the donor–acceptor copolymer pNDTI-TT. Next, we address a bottle neck of OECT stability, demonstrating that although oxygen is a source of degradation for OECTs, it can also behave as a p-dopant. We develop a new technique to improve OECT stability by combining solvent degassing and chemical doping resulting in improved ON/OFF current ratios, carrier mobility, and transconductance, while achieving record-high stability in aqueous electrolytes under ambient operation with an aqueous electrolyte. Finally, the relationship between chemical doping and the stability in OECTs is investigated. Bias stress testing reveals that OECT stability depends on the chemical dopant used and doping concentration.
Overall, the work presented here demonstrates chemical doping is a powerful tool for not only enhancing OECT performance, but also for stabilizing devices against environmental and operational stress. By demonstrating chemical dopants as a way to enhance OECT performance and then showing their role in improving stability, this thesis establishes design rules for doped OMIECs and works toward developing stable, high-performance OECT technologies.
Digital Object Identifier (DOI)
https://doi.org/10.13023/etd.2025.589
Funding Information
This dissertation work was supported by the National Science Foundation (NSF) through cooperative agreement number 1849213 for financial support.
Recommended Citation
Le, Vianna, "CHEMICAL DOPING FOR IMPROVED STABILITY AND PERFORMANCE IN ORGANIC ELECTROCHEMICAL TRANSISTORS" (2025). Theses and Dissertations--Chemical and Materials Engineering. 182.
https://uknowledge.uky.edu/cme_etds/182
Included in
Chemical Engineering Commons, Electronic Devices and Semiconductor Manufacturing Commons, Polymer and Organic Materials Commons, Semiconductor and Optical Materials Commons
