A High-Speed Charge Injection Circuit for Nanosecond-Scale Electrochemical Measurements

This paper describes a GaNFET-based high-speed charge injection circuit to study fast redox processes at electrode-electrolyte interfaces. The circuit allows the rates of electrode processes, which are much faster than those accessible with a conventional potentiostat, to be measured. It is able to inject charge across the interface within a few nanoseconds, and also to hold the potential generated across the cell following injection for up to 1 s without appreciable (less than 1%) decay. In addition, the circuit can still monitor the current flowing through the cell, as in a conventional potentiostat. Preliminary test results with both a dummy load and a custom two-electrode electrochemical cell confirm the functionality of the proposed circuit.