Nanoscale Imaging of Surface Topography and Reactivity with the Scanning Electrochemical Microscope

Laforge, François O.; Velmurugan, Jeyavel; Wang, Yixian; Mirkin, Michael V.

doi:10.1021/ac900335c

Cited by 91 publications

(95 citation statements)

References 41 publications

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“…To address this issue, in this paper, we describe a powerful approach for visualizing redox activity at complex composite electrodes at high spatial resolution. Although electrochemical imaging via scanning electrochemical microscopy (SECM) can achieve high resolution in certain applications, such measurements are rare and tend to be applied to flat (topographically uninteresting) surfaces if activity is to be measured quantitatively 8,9 .…”

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confidence: 99%

Nanoscale visualization of redox activity at lithium-ion battery cathodes

et al. 2014

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Intercalation and deintercalation of lithium ions at electrode surfaces are central to the operation of lithium-ion batteries. Yet, on the most important composite cathode surfaces, this is a rather complex process involving spatially heterogeneous reactions that have proved difficult to resolve with existing techniques. Here we report a scanning electrochemical cell microscope based approach to define a mobile electrochemical cell that is used to quantitatively visualize electrochemical phenomena at the battery cathode material LiFePO 4 , with resolution of B100 nm. The technique measures electrode topography and different electrochemical properties simultaneously, and the information can be combined with complementary microscopic techniques to reveal new perspectives on structure and activity. These electrodes exhibit highly spatially heterogeneous electrochemistry at the nanoscale, both within secondary particles and at individual primary nanoparticles, which is highly dependent on the local structure and composition.

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confidence: 99%

Nanoscale visualization of redox activity at lithium-ion battery cathodes

et al. 2014

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“…The reliable fabrication of nanoelectrodes with a small ratio of electrodeinsulation to active electrode (RG) is of particular importance to improve SECM spatial resolution (2). In particular, a variety of different approaches have been adopted to create small electrodes with thin insulating coats such as photolithography (3), chemical vapor deposition (4), electrodeposited paint methods (5,6), laser pulling techniques (7)(8)(9)(10)(11), and pyrolytic carbon deposition (12)(13)(14)(15). Photolithography and chemical vapor deposition can be used to make thin insulation layers, but pinholes are often a problem.…”

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confidence: 99%

“…AFM (4,5,16), shear force (3,(17)(18)(19), impedance (14,(20)(21)(22), faradaic current (7,14,23), ion current (6,15,24), and electrochemical (25-27) feedback distance-control systems have been developed, but many of these required additional probe modifications for distance control. Impedance-feedback and constant-current distance control are effective methods to obtain high-resolution topography images because they do not require additional modification of the electrode for distance control.…”

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Topographical and electrochemical nanoscale imaging of living cells using voltage-switching mode scanning electrochemical microscopy

Takahashi

Shevchuk

Novák

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

202

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We describe voltage-switching mode scanning electrochemical microscopy (VSM-SECM), in which a single SECM tip electrode was used to acquire high-quality topographical and electrochemical images of living cells simultaneously. This was achieved by switching the applied voltage so as to change the faradaic current from a hindered diffusion feedback signal (for distance control and topographical imaging) to the electrochemical flux measurement of interest. This imaging method is robust, and a single nanoscale SECM electrode, which is simple to produce, is used for both topography and activity measurements. In order to minimize the delay at voltage switching, we used pyrolytic carbon nanoelectrodes with 6.5-100 nm radii that rapidly reached a steady-state current, typically in less than 20 ms for the largest electrodes and faster for smaller electrodes. In addition, these carbon nanoelectrodes are suitable for convoluted cell topography imaging because the RG value (ratio of overall probe diameter to active electrode diameter) is typically in the range of 1.5-3.0. We first evaluated the resolution of constant-current mode topography imaging using carbon nanoelectrodes. Next, we performed VSM-SECM measurements to visualize membrane proteins on A431 cells and to detect neurotransmitters from a PC12 cells. We also combined VSM-SECM with surface confocal microscopy to allow simultaneous fluorescence and topographical imaging. VSM-SECM opens up new opportunities in nanoscale chemical mapping at interfaces, and should find wide application in the physical and biological sciences.high-resolution imaging | living cell imaging | noninvasive | constant-distance mode S canning electrochemical microscopy (SECM) uses an electrode tip for detecting electroactive chemical species and is an effective tool for the investigation of the localized chemical properties of sample surfaces and interfaces (1). Because SECM has high temporal resolution and can be used under physiological conditions, it is particularly well suited for quantitative measurements of (short-lived) chemicals like neurotransmitters, nitric oxide, reactive oxygen species, and oxygen, which are released/ consumed by living cells. In conventional SECM, the probe is often micrometer scale and the probe vertical position is kept at a constant height, a plane, during probe scanning. If the sample topography is not flat, the electrode-sample separation changes during scanning, complicating the SECM measurement and its analysis.Various methods for SECM electrode miniaturization and control of the electrode-sample separation have been advocated in order to improve the resolution of SECM imaging. The reliable fabrication of nanoelectrodes with a small ratio of electrodeinsulation to active electrode (

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“…Nanoelectrodes have recently been reviewed [35], and reports of such tips being used for nanoscale electrochemical imaging in SECM are now appearing [36,37]. Polished Pt-disk nanoelectrodes have been used for constant-height imaging, using an electrochemical response to determine topography [36], and similar probes have also been used for electrochemical imaging of cells [37].…”

Section: Introductionmentioning

confidence: 99%

“…Polished Pt-disk nanoelectrodes have been used for constant-height imaging, using an electrochemical response to determine topography [36], and similar probes have also been used for electrochemical imaging of cells [37]. For pulled Pt tips, the Pt may be exposed using hydrofluoric acid to etch the glass to produce a finite coneshaped electrode [38], or by micropolishing the tip to produce a disk electrode [32].…”

Section: Introductionmentioning

confidence: 99%

Nanoscale intermittent contact-scanning electrochemical microscopy

Lazenby

McKelvey

Peruffo

et al. 2013

J Solid State Electrochem

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Contribution to the Festschrift for Allen J. Bard, on the occasion of his 80 th birthday.2 Abstract A major theme in scanning electrochemical microscopy (SECM) is methodology for nanoscale imaging with distance control and positional feedback of the tip. We report the expansion of intermittent contact (IC)-SECM to the nanoscale, using disk-type Pt nanoelectrodes prepared using the laser-puller sealing method. The Pt was exposed using a focused ion beam milling procedure to cut the end of the electrode to a well-defined glass sheath radius, which could also be used to reshape the tips to reduce the size of the glass sheath. This produced nanoelectrodes that were slightly recessed, which was optimal for IC-SECM on the nanoscale, as it served to protect the active part of the tip. A combination of finite element method simulations, steady-state voltammety and scanning electron microscopy, for the measurement of critical dimensions, was used to estimate Pt recession depth. With this knowledge, the tip-substrate alignment could be further estimated by tip approach curve measurements. IC-SECM has been implemented by using a piezo-bender actuator for the detection of damping of the oscillation amplitude of the tip, when IC occurs, which was used as a tip position feedback mechanism. The piezo-bender actuator improves significantly on the performance of our previous setup for IC-SECM, as the force acting on the sample due to the tip is greatly reduced, allowing studies with more delicate tips. The capability of IC-SECM is illustrated with studies of a model electrode (metal/glass) substrate.

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Nanoscale Imaging of Surface Topography and Reactivity with the Scanning Electrochemical Microscope

Cited by 91 publications

References 41 publications

Nanoscale visualization of redox activity at lithium-ion battery cathodes

Nanoscale visualization of redox activity at lithium-ion battery cathodes

Topographical and electrochemical nanoscale imaging of living cells using voltage-switching mode scanning electrochemical microscopy

Nanoscale intermittent contact-scanning electrochemical microscopy

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