Agilent 5991-3298EN In Situ Electrochemical Measurements Using the 7500 AFM - Application Note c20141020 [4] free download

File name 5991-3298EN In Situ Electrochemical Measurements Using the 7500 AFM - Application Note c20141020 [4]

Keysight Technologies In Situ Electrochemical Measurements Using Keysight 7500 AFM Application Brief Introduction control both the potential of the sample and the potential of the probe versus the same refer- EC-SPM essentially combines two valuable, ence electrode. As with usual STM imaging, the independent techniques: electrochemistry (EC) tunneling current between the tip and the sample and scanning probe microscopy (SPM). The depends on the potential difference as well as electrochemical unit includes a potentiostat and the distance between the two, and is used as a three-electrode cell that controls the electro- the control signal for STM image formation. In chemical state of the working electrode, usually EC-STM, the morphological information about the sample. The scanning probe microscope the electrode surface under potential control can characterizes the surface of the solid electrode be imaged in constant-current mode, and the with either a passive or an active probe. changes in the localized electronic state of the electrode surface with electrochemical poten- With a passive probe like that utilized in EC- tial can be studied using "current vs. voltage" AFM, the potential of the probe is not controlled. spectroscopy. Thus, the AFM cantilever acts as an inert probe that monitors the topographic changes of the EC-SPM can deliver nanometer-scale resolution electrode surface caused by electrochemical of the electrode surface in liquid. The true merit processes (using standard AFM imaging modes). of EC-SPM, however, is the capability to control the experimental conditions (e.g., temperature On the other hand, with an active probe like that and humidity) and mimic the real-world environ- utilized in EC-STM, a bipotentiostat is used to ment of the sample under test. This is particularly important for energy and corrosion research. 02 | Keysight | In Situ Electrochemical Measurements Using Keysight 7500 AFM - Application Brief Instrumentation The Keysight 7500 can also be equipped with an optional bipotentiostat that The Keysight Technologies, Inc. 7500 AFM/ enables stable electrochemistry control SPM microscope is a high-performance in either EC-AFM or EC-STM mode. The instrument that delivers high-resolution bipotentiostat offers a series of different