Suspended highly 3D interdigitated carbon microelectrodes
Ioannis Mantis, Suhith Hemanth, Claudia Caviglia, Arto Heiskanen, Stephan Sylvest Keller
Abstract
3D interdigitated pyrolytic carbon microelectrodes (3D IDE) with high complexity and interconnectivity were fabricated taking advantage of suspended interdigitated microstructures. A novel fabrication method for a 3D interdigitated polymer precursor template was developed based on a dual photoresist process including multiple UV exposures at two different wavelengths. The precursor structures were subsequently pyrolyzed at 1100°C for 1 h in N2 environment to obtain 3D interdigitated carbon microelectrodes. Different 3D electrode designs were fabricated and the electrochemical performance was evaluated by cyclic voltammetry and electrochemical impedance spectroscopy (EIS). 3D IDE with smaller structural dimensions displayed ultra-microelectrode (UME)-like behavior with a sigmoidal shape of the cyclic voltammograms (CV) and the absence of the linear diffusion regime in EIS. Furthermore, the 3D IDE displayed 2-fold higher peak currents in CV and significantly reduced charge transfer resistance compared to 2D IDE.