Focused ion beam fabrication of high-resolution electrochemical-electroluminescence coupling bipolar nanoelectrode array sensors

Abstract

High temporal and spatial resolution electrochemical sensor arrays can greatly benefit various parallel sensing applications. Herein, we provide a simple method for the controlled and scaled fabrication of bipolar nanoelectrode arrays (BPnEAs) for high-resolution electrochemical sensing applications. BPnEAs are prepared on silicon nitride film windows through the dual-beam FIB nanofabrication technique. Coupling a conventional electrochemical redox reaction with a tris (2,20-bipyridyl) ruthenium /2-(dibutylamino)ethanol electrochemiluminescence (ECL) system, which is based on a high-viscosity solvent to reduce molecular diffusion, allows for the reporting of conventional electrochemical redox processes with high spatial and temporal resolution. The use of the BPnEA-ECL sensor is demonstrated on 10 × 10 Pt or C BPnEAs for monitoring the reduction of 0.5 M H2SO4. BPnEA-ECL sensors containing different electrode materials (Pt and C) are reported for the first time and are used to monitor the reduction of 0.5 M H2SO4, thus revealing the difference in electrocatalytic capacities between Pt and C. Subsequently, we reveal the outstanding capabilities of the BPnEA-ECL system for catalyst screening.

Keywords

• Bipolar electrode array
• Focused ion beam fabrication
• Parallel sensing
• Electrochemical imaging