Combined Scanning Electrochemical−Atomic Force Microscopy

Abstract

A combined scanning electrochemical microscope (SECM)-atomic force microscope (AFM) is described. The instrument permits the first simultaneous topographical and electrochemical measurements at surfaces, under fluid, with high spatial resolution. Simple probe tips suitable for SECM-AFM, have been fabricated by coating flattened and etched Pt microwires with insulating, electrophoretically deposited paint. The flattened portion of the probe provides a flexible cantilever (force sensor), while the coating insulates the probe such that only the tip end (electrode) is exposed to the solution. The SECM-AFM technique is illustrated with simultaneous electrochemical-probe deflection approach curves, simultaneous topographical and electrochemical imaging studies of track-etched polycarbonate ultrafiltration membranes, and etching studies of crystal surfaces.

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

“…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.…”

Methods of photoelectrode characterization with high spatial and temporal resolution

“…Of particular interest are in situ, in operando studies of immersed interfaces under electrochemical control (EC-AFM). 113 EC-AFM has been particularly useful for monitoring changes in morphology of semiconductor surfaces due to corrosion, 114,115 including in the photoelectrochemical environment. 114,116 The use of EC-AFM to better understand corrosion and other degradation mechanisms of photoelectrodes could be very useful for the PEC field.…”

“…The combination of SECM with AFM has been used to correlate nano-or micron-scale variation in (photo)catalytic activity to topological features such as grain boundaries, catalyst particles, and more. 113,301,302 Combined AFM/STM enables simultaneous measurements of the force and conductance curves of two impinging double layers in the electrochemical environment, while the natural pairing of Raman mapping and SPCM offers the ability to investigate variations in local photocurrent as a function of the chemical or physical nature of the photoelectrode surface. Other examples of combined in situ measurements that have been reported include SPCM/SECM, 12,31,56,58,303 SPCM/shear force topography, 45 SECM/AFM, 301 and Raman/SPCM, 304 SECM/optical microscopy(OM), 305,306 ECSTM/SECM, 93,94,307 NSOM/fluorescence spectroscopy, 308,309 and ECSTM/TERS.…”

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

“…the oxygen reduction) for determining the working distance was also reported [20]. An alternative route is the combination of SECM with other scanning probe techniques that can control the probe-sample distance, such as scanning force microscopy (SFM) [24][25][26][27][28][29][30], electrochemical scanning tunnelling microscopy (ECSTM) [31,32], and scanning ion-conductance microscopy (SICM) [33,34]. Other SECM hybrid techniques for distance control rely on the reduced damping of a vertically or laterally vibrated probe in close proximity to the substrate.…”