Combined electrochemical-topographical imaging: a critical review

Abstract

The ability to characterise electrochemical interfaces on a localised scale has revolutionised our understanding of spatially heterogeneous surface processes. Advances in scanning electrochemical microscopy (SECM) over the past decade have not only permitted access to information at progressively smaller scales but have moreover enabled the simultaneous imaging of interfacial activity and surface topography. Such measurements play a key role in developing a better grasp of structure-activity relationships relevant to a wide range of applications in chemistry and biology. This review critically analyses the state-of-the-art in correlative electrochemical-topographical imaging, focusing on four predominant approaches to probe positional feedback: atomic force microscopy (AFM); shear-force; ion conductance; and electrochemical positioning. The relative advantages and disadvantages of each of these techniques is considered and their imaging characteristics critically compared, with a perspective on the potential for future improvement. Fig. 7 Shear-force SECM of an embedded diamond nanoelectrode measured in feedback mode. The position of the embedded electrode is clear from the electrochemical signal (a) but not on the topography (b). Images adapted with permission from ref. 96.

Probing of Local Multifield Coupling Phenomena of Advanced Materials by Scanning Probe Microscopy Techniques

“…This type of electrochemically active ferroelectrics manifests the multifield EMCC phenomena. Generally speaking, EC‐AFM has been the primary SPM technique to study ECC for many years …”

“…Figure shows the basic setups of some representative SPM techniques. The most used SPM techniques include contact/noncontact/tapping‐mode AFM, conductive AFM (C‐AFM) (Figure i), Kelvin probe force microscopy (KPFM) (Figure ii), electrostatic force microscopy (EFM), magnetic force microscopy (MFM), scanning thermal microscopy (SThM), electrochemical AFM (EC‐AFM), piezoresponse force microscopy (PFM) (Figure iii), electrochemical strain microscopy (ESM), contact resonance force microscopy (CR‐FM) (Figure iv), and multifrequency AFM such as AM–FM (amplitude modulation–frequency modulation) and bimodal AFM, and many others. Some of the SPM measurements results are illustrated in Figure .…”

Advances and Perspectives in Chemical Imaging in Cellular Environments Using Electrochemical Methods

“…Methods of tip-substrate distance regulation for SECM [23] include simply using the faradaic current, the use of impedance in alternating current (AC)-SECM [24], the use of oscillating probes in Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 23 April 2018 doi:10.20944/preprints201804.0300.v1…”

Advances and Perspectives in Chemical Imaging in Cellular Environments Using Electrochemical Methods

“…Methods of tip-substrate distance regulation for SECM [27] include simply using the faradaic current, the use of impedance in alternating current (AC)-SECM [28], the use of oscillating probes in tip-position modulation (TPM)-SECM [29], shear-force SECM [30], intermittent contact (IC)-SECM [31], and three-dimensional super-resolution optical imaging [32]. There are advantages and limitations to each of these techniques, for example the faradaic current is somewhat limited by the fact that the current response at an electrode is affected by both the tip-substrate separation distance and the electroactivity of the underlying substrate.…”