Proceedings of MATSUS Fall 2023 Conference (MATSUSFall23)
DOI: https://doi.org/10.29363/nanoge.matsus.2023.181
Publication date: 18th July 2023
Doping of organic semiconductor films enhances their conductivity for applications in organic electronics, thermoelectrics and bioelectronics. However, much remains to be learnt about the properties of the conductive charges in order to optimize the design of the materials. Electrochemical doping is important for organic electrochemical transistors (OECTs) used in biomedical sensors. Benefits of doping via electrochemistry include controllable doping levels, reversibility and high achievable carrier densities. We introduce a new technique, applying in-situ terahertz (THz) spectroscopy directly to electrochemically doped polymers in combination with time-resolved spectro-electrochemistry, chronoamperometry and OECT device measurements. We evaluate the intrinsic short-range transport properties of the polymers (without the effects of long-range disorder, grain boundaries and contacts), while precisely tuning the doping level via the applied oxidation voltage. Moreover, temperature-dependent measurements allow to extract the thermodynamic and activation parameters of the electrochemical processes. Results will be shown for a variety of polymers based on polythiophene backbones with different sidechains, aligned polymer chains and novel 2D organic films.