Chemical Imaging of Surfaces with the Scanning Electrochemical Microscope

Abstract

Scanning electrochemical microscopy is a scanning probe technique that is based on faradaic current changes as a small electrode is moved across the surface of a sample. The images obtained depend on the sample topography and surface reactivity. The response of the scanning electrochemical microscope is sensitive to the presence of conducting and electroactive species, which makes it useful for imaging heterogeneous surfaces. The principles and instrumentation used to obtain images and surface reaction-kinetic information are discussed, and examples of applications to the study of electrodes, minerals, and biological samples are given.

Peer Reviewed: Atomic Force Microscopy Probes Go Electrochemical

“…This technique is frequently used to image live cells (20), but in conventional form it is nonspecific to ionic species. SECM has provided considerable new quantitative insights into interfacial processes, as illustrated schematically in Figure 2a (11,12,18). In each of these examples, the tip is amperometric and the current flow provides information on the underlying surface process.…”

“…Scanning electrochemical microscopy (SECM) is the most widely used electrochemically based SPM technique (11)(12)(13)(14). An ultramicroelectrode (UME) with micrometer dimensions usually serves as the imaging tip, but nanometer-sized electrodes are becoming more widespread (15)(16)(17).…”

Classification of Scanning Probe Microscopies

“…If the tip is brought close to a conductive surface which is held at a potential to produce ionic products contributing to the tip current, an increased current will be measured. Thus, the method is sensitive both towards tip-sample separation and to the nature of the surface, opening up the possibility to study electrochemical processes on a wide variety of materials [109].…”

High-throughput scanning electrochemical microscopy brushing of strongly tilted and curved surfaces

“…Scanning electrochemical microscopy (SECM) is a scanning probe technique that is conventionally carried out with an amperometric disc-shaped ultramicroelectrode (UME; typically denoted as "tip") localized in the vicinities of a sample substrate and in presence of an electrolyte solution [1][2][3][4]. Redox-active species detected or generated at the UME and/or sample are employed to determine local surface reactivity or to manipulate interfaces with micro-and submicrometer resolution [5][6][7][8][9][10][11].…”