Agilent 5991-4600EN Combining Atomic Force Microscopy with Scanning Electrochemical Microscopy - Application free download

File name 5991-4600EN Combining Atomic Force Microscopy with Scanning Electrochemical Microscopy - Application

Keysight Technologies Combining Atomic Force Microscopy with Scanning Electrochemical Microscopy Application Note Introduction Scanning probe microscopy (SPM) techniques have found a broad range of applications in characterizing the physical and chemical properties of the surface of interested materials. One technique that is particularly useful for studying localized electrochemical activities at the solid/liquid and liquid/ liquid interface is Scanning Electrochemical Microscopy (SECM), which was introduced by Bard and coworkers in 1986[1]. Laterally resolved, in situ electrochemical information of surface properties can be obtained by scanning an ultramicroelectrode (UME) at a defined distance across the sample surface. Even though it looks similar to other SPM techniques in the sense that it involves the control of scanning a physical probe across a sample surface, the operation principle for a conventional SECM is quite different. SECM characterizes the localized properties of the electrified solid/liquid and liquid/ liquid interfaces by monitoring the electrochemical current. When the electrode is swept across a sample surface, changes in current allow imaging of insulating and conducting surfaces for topology and reactivity information. A detailed introduction of SECM and its applications are found in a separate note. PD Dr. Christine Kranz, Institute of Analytical and Bioanalytical Chemistry, University of Ulm Dr. Shijie Wu, Keysight Technologies, Inc. The Bifunctional AFM-SECM Probe SECM imaging is commonly operated in constant-height mode, where the tip is held at a fixed position above the sample surface. The spatial resolution of SECM depends significantly on the size and geometry of the UME and the substrate-to-tip distance. One major drawback of constant height operation in SECM is the lack of sufficient spatial resolution due to current dependent positioning of the microelectrode and the convolution of topographical and electrochemical information. The EC SmartCart probe offered by Keysight Technologies, Inc. provides an innovative solution to this problem, which directly integrates a micro- or nanoelectrode into an AFM probe. This integrated probe (the AFM-SECM probe) maintains the functionality of both AFM and SECM technique, by integrating a sub-microelectrode recessed from the end of the AFM tip [2]. Consequently, the electrode is located at a pre- Non-conductive defined distance to the sample surface, determined by the height of the actual AFM tip AFM tip (Fig. 1). Thus, in-situ (electro)chemical information on a wide range