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Probing the Speed Limits of Scanning Electrochemical Microscopy with In situ Colorimetric Imaging
Author(s) -
Dorfi Anna E.,
Zhou Shijie,
West Alan C.,
Wright John,
Esposito Daniel V.
Publication year - 2020
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.202000476
Subject(s) - scanning electrochemical microscopy , microscopy , in situ , substrate (aquarium) , electrode , microelectrode , signal (programming language) , materials science , chemistry , nanotechnology , optics , analytical chemistry (journal) , electrochemistry , physics , computer science , oceanography , organic chemistry , geology , chromatography , programming language
Due to the complex nature of probe/substrate interactions in scanning electrochemical microscopy (SECM), SECM has been primarily limited to well‐defined probe geometries and slow scan speeds that reduce imaging throughput. Herein, we show that in situ colorimetric visualization of concentration gradients using pH indicator dyes during SECM measurements can be a powerful tool for understanding the coupled influences of probe geometry and scan speed on the dynamics of localized plumes of electroactive species that mediate probe/substrate interactions. Colorimetric images of plumes generated at a band electrode reveal that probe geometry strongly influences linescan signal distortion and hysteresis at scan speeds surpassing the conventional SECM “speed limit”. Combining mechanistic information from in situ colorimetric imaging with transport models, this article reports design principles that have the potential to enable quantitative SECM with novel probe geometries and at imaging rates that are at least an order of magnitude faster than currently employed.