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Abstract
Mass-transport-limited catalysis and membrane transport can be characterized by concentration profiles surrounding active surfaces. Scanning electrochemical microscopy (SECM) is a tool that has been used to measure concentration profiles; however, the presence and geometry of the tip can distort these profiles due to hindered diffusion, which in turn alters chemical behavior at the catalytic surface. To fully characterize the behavior of surface features such as catalytic sites, it is essential to account for and analytically remove the effect of tip presence. In this work, atomic force microscopy-based SECM (AFM-SECM) measurements over poly(tetrafluoroethylene) (PTFE) and gold electrode surfaces are used to measure negative and positive-feedback approach curves, respectively. By inversely fitting these approach curves with a finite element method (FEM) model, we derive kinetic and geometric tip parameters that characterize the effect of tip presence. Tip effects may be removed in the model to estimate concentration profiles and reaction properties for the case where no tip is present. A maximum 120% increase in the concentration at one tip radii above the surface is observed due to the presence of the tip, where the concentration field is compressed vertically, in proportion to surface feature size and tip separation. Conical AFM-SECM tips, with a higher ratio of tip height to the base size, introduce less concentration distortion than disk-shaped AFM-SECM tips.
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Affiliation(s)
- Alex Mirabal
- Department of Chemical Engineering and Material Science, Michigan State University, East Lansing, Michigan 48824, United States
| | - Scott Calabrese Barton
- Department of Chemical Engineering and Material Science, Michigan State University, East Lansing, Michigan 48824, United States
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2
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Polonschii C, Gheorghiu M, David S, Gáspár S, Melinte S, Majeed H, Kandel ME, Popescu G, Gheorghiu E. High-resolution impedance mapping using electrically activated quantitative phase imaging. LIGHT, SCIENCE & APPLICATIONS 2021; 10:20. [PMID: 33479199 PMCID: PMC7820407 DOI: 10.1038/s41377-020-00461-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 12/16/2020] [Accepted: 12/29/2020] [Indexed: 05/23/2023]
Abstract
Retrieving electrical impedance maps at the nanoscale rapidly via nondestructive inspection with a high signal-to-noise ratio is an unmet need, likely to impact various applications from biomedicine to energy conversion. In this study, we develop a multimodal functional imaging instrument that is characterized by the dual capability of impedance mapping and phase quantitation, high spatial resolution, and low temporal noise. To achieve this, we advance a quantitative phase imaging system, referred to as epi-magnified image spatial spectrum microscopy combined with electrical actuation, to provide complementary maps of the optical path and electrical impedance. We demonstrate our system with high-resolution maps of optical path differences and electrical impedance variations that can distinguish nanosized, semi-transparent, structured coatings involving two materials with relatively similar electrical properties. We map heterogeneous interfaces corresponding to an indium tin oxide layer exposed by holes with diameters as small as ~550 nm in a titanium (dioxide) over-layer deposited on a glass support. We show that electrical modulation during the phase imaging of a macro-electrode is decisive for retrieving electrical impedance distributions with submicron spatial resolution and beyond the limitations of electrode-based technologies (surface or scanning technologies). The findings, which are substantiated by a theoretical model that fits the experimental data very well enable achieving electro-optical maps with high spatial and temporal resolutions. The virtues and limitations of the novel optoelectrochemical method that provides grounds for a wider range of electrically modulated optical methods for measuring the electric field locally are critically discussed.
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Affiliation(s)
| | | | - Sorin David
- International Centre of Biodynamics, 060101, Bucharest, Romania
| | | | - Sorin Melinte
- Institute of Information and Communication Technologies, Electronics and Applied Mathematics, Université Catholique de Louvain, 1348, Louvain-la-Neuve, Belgium
| | - Hassaan Majeed
- Quantitative Light Imaging Laboratory, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Mikhail E Kandel
- Quantitative Light Imaging Laboratory, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Gabriel Popescu
- Quantitative Light Imaging Laboratory, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
| | - Eugen Gheorghiu
- International Centre of Biodynamics, 060101, Bucharest, Romania.
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3
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Abstract
To achieve super-resolution scanning electrochemical microscopy (SECM), we must overcome the theoretical limitation associated with noncontact electrochemical imaging of surface-generated species. This is the requirement for mass transfer to the electrode, which gives rise to the diffusional broadening of surface features. In this work, a procedure is developed for overcoming this limitation and thus generating "super-resolved" images using point spread function (PSF)-based deconvolution, where the point conductor plays the same role as the point emitter in optical imaging. In contrast to previous efforts in SECM towards this goal, our method uses a finite element model to generate a pair of corresponding blurred and sharp images for PSF estimation, avoiding the need to perform parameter optimization for effective deconvolution. It can therefore be used for retroactive data treatment and an enhanced understanding of the structure-property relationships that SECM provides.
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Affiliation(s)
- Lisa I Stephens
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
| | - Nicholas A Payne
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
| | - Janine Mauzeroll
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
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4
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Stephens LI, Payne NA, Skaanvik SA, Polcari D, Geissler M, Mauzeroll J. Evaluating the Use of Edge Detection in Extracting Feature Size from Scanning Electrochemical Microscopy Images. Anal Chem 2019; 91:3944-3950. [DOI: 10.1021/acs.analchem.8b05011] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Lisa I. Stephens
- Department of Chemistry, McGill University, Montreal, QC H3A 0B8, Canada
| | - Nicholas A. Payne
- Department of Chemistry, McGill University, Montreal, QC H3A 0B8, Canada
| | | | - David Polcari
- Department of Chemistry, McGill University, Montreal, QC H3A 0B8, Canada
| | - Matthias Geissler
- Life Sciences Division, National Research Council of Canada, 75 de Mortagne Boulevard, Boucherville, QC J4B 6Y4, Canada
| | - Janine Mauzeroll
- Department of Chemistry, McGill University, Montreal, QC H3A 0B8, Canada
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5
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Hui J, Gossage ZT, Sarbapalli D, Hernández-Burgos K, Rodríguez-López J. Advanced Electrochemical Analysis for Energy Storage Interfaces. Anal Chem 2018; 91:60-83. [PMID: 30428255 DOI: 10.1021/acs.analchem.8b05115] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Jingshu Hui
- Department of Chemistry , University of Illinois at Urbana-Champaign , 600 South Mathews Avenue , Urbana , Illinois 61801 , United States
| | - Zachary T Gossage
- Department of Chemistry , University of Illinois at Urbana-Champaign , 600 South Mathews Avenue , Urbana , Illinois 61801 , United States
| | - Dipobrato Sarbapalli
- Department of Materials Science and Engineering , University of Illinois at Urbana-Champaign , 1304 West Green Street , Urbana , Illinois 61801 , United States
| | - Kenneth Hernández-Burgos
- Department of Chemistry , University of Illinois at Urbana-Champaign , 600 South Mathews Avenue , Urbana , Illinois 61801 , United States.,Beckman Institute for Advanced Science and Technology , 405 North Mathews Avenue , Urbana , Illinois 61801 , United States
| | - Joaquín Rodríguez-López
- Department of Chemistry , University of Illinois at Urbana-Champaign , 600 South Mathews Avenue , Urbana , Illinois 61801 , United States.,Beckman Institute for Advanced Science and Technology , 405 North Mathews Avenue , Urbana , Illinois 61801 , United States
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6
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Bentley CL, Edmondson J, Meloni GN, Perry D, Shkirskiy V, Unwin PR. Nanoscale Electrochemical Mapping. Anal Chem 2018; 91:84-108. [PMID: 30500157 DOI: 10.1021/acs.analchem.8b05235] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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