Three-dimensional graphene nanosheet encrusted carbon micropillar arrays for electrochemical sensing

Integrating graphene onto three-dimensional (3D) microelectrodes is a plausible technique to significantly improve the sensitivity of electrochemical devices. However, the construction of graphene coated 3D microstructures has been a considerable challenge. In this paper, we present a simple methodology using electrostatic spray deposition (ESD) to conformally coat graphene onto 3D carbon micropillars that are fabricated by pyrolyzing finely patterned photoresist. During the ESD, changes in the critical parameters such as substrate temperature, deposition time, and nozzle to substrate distance have shown a significant effect on the morphology of the deposited graphene film. The amperometric response of graphene/carbon micropillar electrode arrays exhibited higher electrochemical activity, improved charge transfer and a linear response towards H₂O₂ detection between 250 μM and 5.5 mM. The ESD technique, with the flexibility of integrating a wide variety of functional nanomaterials onto complex 3D microstructures, is attractive in the field of electrochemistry and biotechnology.