Submicron Probes for Scanning Electrochemical Microscopy

To improve the spatial resolutions of scanning electrochemical microscopy (SECM) imaging, the laser-pulled submicron electrode fabrication method was explored in this work. Manual polishing of a laser-pulled Pt nanoelectrode exposed a Pt tip diameter of 250 nm with a ratio of the tip glass to exposed Pt disc (RG) 30. This fabricated submicron probe was then utilized to study the electrochemical functionality of an independently addressable microband electrode (IAME) sample using SECM. In the constant imaging mode of SECM, where the probe is scanned linearly across the sample at a fixed z position, SECM demonstrated higher resolution than that of the conventional micrometer electrodes when the feedback currents from the Pt and glass microbands were characterized. In addition, the depth scan imaging mode of SECM was also used to extract experimental horizontal line scans and probe approach curves for analysis. 3D simulations of the IAME-SECM probe experiments were explored for the first time to quantify the tip-to-sample distances, tilt angle of the sample (or electrode) and height of the Pt microbands. The experimentally characterized height was found to be similar to manufacturer specification (125 nm vs 110 nm). Furthermore, the more computationally-demanding 3D simulation of the true IAME sample geometry (110 nm height of the Pt microbands) revealed minimal difference in feedback behaviors in comparison to the idealized flat geometry. The removal of this simulation complexity was proved to be sufficient for SECM analysis of the IAME sample by a 250 nm Pt probe, which saves greatly the computation resources.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author