Charge-injection waveforms for iridium oxide (AIROF) microelectrodes

The charge-injection limits of activated iridium oxide (AIROF) microelectrodes subjected to charge-balanced biphasic current pulsing are investigated as a function of anodic bias and asymmetry in the cathodic and anodic pulse widths. The use of asymmetric waveforms, in which the charge balancing anodic phase is delivered at a lower current density and longer pulse width, permits the use of anodic biasing to maximize charge-injection capacity. The need for more sophisticated driving waveforms and how these could be implemented in modern ASIC design to achieve optimal charge-injection is discussed.