Characteristics of Transparent, PEDOT:PSS Coated Indium-Tin-Oxide (ITO) Microelectrodes.

ABSTRACT

This paper reports on electrochemical and optical characteristics of flexible, transparent microelectrodes, which consist of thin poly-(3, 4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOTPSS) spun onto indium-tin-oxide (ITO) electrodes for potential applications in biomedical optoelectronic devices. Although PEDOTPSS/ITO combined films have been extensively investigated for applications in optical devices, such as solar cells and LEDs, PEDOTPSS/ITO films for use in electrophysiological recording have not been well-characterized yet. In this work, PEDOTPSS coated ITO microelectrodes with various diameters of 10 µm, 37 µm, 50 µm and 80 µm were microfabricated and characterized, and their properties were compared with plain ITO microelectrodes. Experimental results demonstrate that PEDOTPSS coated ITO electrodes exhibit decreased electrochemical impedance, well-performed stability in saline, and increased charge storage capacity while preserving excellent optical transparency and mechanical flexibility. Equivalent circuit models were fitted to the experimental results to analytically extract interface capacitance, charge transfer resistance and solution resistance at the electrode-electrolyte interface.