Abstract-A Terahertz-Transparent Electrochemical Cell for In Situ THz Spectroelectrochemistry

Coleen T. Nemes, John R. Swierk, Charles A. Schmuttenmaer

https://pubs.acs.org/doi/abs/10.1021/acs.analchem.7b04204?mi=aayia761&af=R&AllField=nano&target=default&targetTab=std

Terahertz spectroscopy is broadly applicable for the study of a wide variety of materials, but spectroelectrochemistry has not been performed in the THz range due to the lack of a THz-transparent electrochemical cell. While THz-transparent electrodes do exist, they had never been utilized in a complete three-electrode cell, which is the configuration required for accurate potential control in aqueous media. We have designed and constructed a THz-transparent three-electrode elec-trochemical cell and have performed THz spectroelectrochemistry of a SnO2 thin film. The cell utilizes a custom-made reference electrode and tubing which allows the composition of electrolyte to be changed during an experiment. THz spectroelectrochemical measurements show a decrease in THz transmission at potentials where SnO2 conduction band states are potentiostatically filled. We also describe a simple method for measuring the uncompensated resistance and RC time constant.