This project is funded by the Chemical Measurement and Imaging program of the Chemistry Division. Professors Daniel Esposito and John Wright of Columbia University are developing new approaches to scanning electrochemical microscopy (SECM) that will enable high resolution chemical imaging over large areas. SECM is a scanning probe microscopy (SPM) technique that has become invaluable for studying chemical processes across the chemical, physical, and biological sciences. Despite the success of SECM, it is not well suited for high resolution imaging over large areas. This limitation arises because conventional electrochemical probes are scanned in a sequential, point-by-point manner across the area of interest, meaning that high resolution imaging over large areas takes prohibitively long times to complete. The current project aims to break these tradeoffs and enable efficient, high-resolution imaging of large samples by using a combination of new sensing strategies and advanced signal reconstruction methodologies. This approach will greatly reduce imaging times and thereby expand the utility of SECM for many applications. The research plans are tightly integrated with educational and outreach activities.
SECM has become an invaluable tool in many fields of study. However, a major shortcoming of SECM, shared by many SPM techniques, is the trade-off between spatial resolution and areal scan rates. SECM imaging is commonly performed with nanoscale resolution, but such high resolution imaging is typically limited to very small areas (typically << square millimeters). The slow areal scan rates of conventional SECM arise from the fact that the scanning ?point probes?, or ultramicroelectrodes, must be scanned across every (X,Y) location within in an area of interest in a sequential, one-at-a-time manner. This project aims to develop a new approach to SECM imaging that combines i.) non-local continuous line probes (CLPs) and ii.) advanced compressed sensing (CS) signal analysis techniques. While the CLP geometry enables SECM signal to be rapidly measured over large areas, CS serves the critical role of constructing images from the convoluted SECM signal generated by the CLP. The project is organized around three primary objectives: i.) demonstrating the core benefits of combining CLP-SECM with CS, ii.) establishing the theoretical and practical limits of this new approach, and iii.) achieving chemical imaging with nanoscale resolution over macroscopic areas. Research and education are tightly integrated within this interdisciplinary research project, with a strong emphasis on educational activities and workforce training that targets the emerging industries in nanotechnology and signal processing / data analytics.Â
