Towards Operando Electron Transfer Dynamics Measured Using Time-Resolved Terahertz Spectroelectrochemistry

Time-resolved terahertz spectroelectrochemistry measurements were employed to study electron transfer dynamics under an applied bias in dye-sensitized anatase TiO2. These measurements showed that electron trapping was suppressed with a negative applied bias, suggesting that trap states below the band edge were potentiostatically filled. In addition, electron injection dynamics were slowed, consistent with a decrease in density of available acceptor states in the metal oxide conduction band. We also show that care must be taken in selecting appropriately low pump fluences when trying to measure trapping processes in semiconductor materials.