Seeing is Believing: Plasmonic Imaging for Energy and Biomolecular Research at Nanoscale

Abstract:

Energy conversion and storage are extremely important for modern society. Catalysis is the key to improve energy conversion efficiency and has been one of the main focuses of energy research for decades. Nanoscience and nanotechnology have made impressive progress in recent years. To further improve the catalysis efficiency for energy conversion, and to increase energy storage density, we must develop profound understanding of catalytic reaction and build tools to make real-time, spatially resolved measurements at nanoscale. My research career has focused on developing novel plasmonic imaging technologies and applied them to solve critical problems in energy conversion (nano catalysis) and energy storage research. In this presentation, I will introduce two plasmonic imaging techniques I have developed. The first technique is plasmonic-based electrochemical current microscopy (P-ECM) which allows imaging of local catalytic current with ultrahigh speed and sensitivity at nanoscale. To demonstrate the detection limit, I have successfully imaged the catalytic current from single platinum nanoparticles for the first time. The second technique is plasmonic impedance microscopy (PIM) which allows mapping of local impedance. I have mapped the local quantum capacitance of graphene, extracted the defect density, and imaged electron and holes paddles. At the end, I will introduce my recent efforts in biomolecule interaction study and single cell imaging by using nano- and plasmonic imaging techniques.

The second part of the talk will introduce the future research interests which focusing on solving the critical problems in energy and biomolecular research at nanoscale by developing novel imaging and detection techniques. First research direction is to understand the catalytic reaction dynamics on single nanoparticle level. Towards this goal, an imaging platform which is capable of on-site synthesis, characterization, and quantification of the electrocatalytic activities of single nanoparticle will be built. Second, the active edge site of catalytic nanomaterials (2D nanomaterials and nanoparticles) will be studied, and different defect engineering and material synthesis strategies will be invested to improve the catalysis efficiency for energy conversion. For example, photocatalytic efficiency of 2D transition metal dichalcogenides (TMD) materials will be studied for water splitting application. The third research direction will focus on biomolecular study. A charge sensitive nano-oscillator platform will be built to study biomolecular interactions (small molecule-protein, protein-protein interactions) for drug screening and plasmonic sensing platform for protein folding dynamics measurement.

Biography:

Xiaonan Shan received his Bachelor’s and Master’s degree from the Department of Microelectronics from Peking University in China in 2003 and 2006, respectively. He received his Ph.D. in Electrical Engineering from Arizona State University in 2011, where he has developed plasmonic imaging techniques and their applications in nano, energy conversion, and energy storage research. He was a post doc in the Center for Bioelectronics and Biosensors in the Biodesign Institute at ASU from 2011 to 2014, where he has worked on developing novel imaging techniques to study nanomaterials catalytic efficiency and bio-molecular interactions at single cell level. He has been a research assistant professor at the Biodesign Institute since 2014.