In-Situ Electrochemical Microscopy Techniques (AFM-SECM, sMIM and Liquid SEM) to Study Solid/Liquid Interface

Ever since the invention of the scanning probe and electron microscope, a goal has been to image liquid specimens as easily as in a light microscope, and to measure liquid processes with a good resolution in both spatial and temporal. Direct observation of electrochemical processes is essential to develop electrochemical models, optimize nanostructures, and understand reaction mechanisms. We have developed and improved some in-situtechniques and tested them on electrochemical processes. In an attempt to have improved topography and surface reactivity information, we have designed and fabricated nanometer sized scanning probe tips for combined atomic force microscopy (AFM) and scanning electrochemical microscopy (SECM). We report here the characterization of these tips using an in-house fabricated calibration sample and a model anode. In another approach we have used scanning near-field microwave microscopy (sMIM) for imaging in liquids using ultrathin molecular impermeable membranes separating scanning probes from samples enclosed in environmental cells. We imaged a process of dendritic growth during model electroplating reaction. Due to very small energy of few gigahertz microwaves we demonstrate the advantages of this microscopy for non-destructive artifact-free imaging compared to electron microscopy [1]. Different to TEM in liquids which has been used successfully to study the electrochemical processes very little research has been performed using liquid SEM [2]. We explore this imaging modality and describe here a novel chip [3,4] and cell designs enabling us to study Ag electrodeposition in real time using SEM in liquids. All these techniques are complementary and well suited for in situelectrochemistry. These examples demonstrate the versatility of these techniques and can be extended to other applications such as corrosion, battery and bio-medical research. References: [1] A. Tselev, J. Velmurugan, A. Ievlev, S. Kalinin,and A. Kolmakov ACS Nano, 10 (3),3562, 2016 [2] E. Jensen, C. Kobler, P. S. Jensen and K. Molhave, Ultramicroscopy, 129, 63, 2013 [3] F. Yi, W. Osborn, J. Betz, J and D.A. LaVan Microelectromechanical Systems, 24, 1185, 2015 [4] M. D. Grapes, T. LaGrange, L.H. Friedman, B. W. Reed, G. H. Campbell, T. P. Weihs and D. A. LaVan Review of Scientific Instruments, 85, 084902, 2014