CANCELED: Imaging and Controlling Chemical Transformations in Inorganic Nanostructures with Light

Bryce Sadtler, Washington University in St. Louis

This talk will discuss research efforts in our group to use light both to control the growth of inorganic materials and to probe chemical reactions in single particles. Chemists typically use external parameters such as temperature, pressure, and concentration to direct chemical transformations in molecules and materials. Many classes of materials are also responsive to external stimuli, including light. Our research group designs adaptive inorganic materials that adjust their growth in response to illumination to synthesize complex nanostructures and metastable phases that cannot be made by conventional methods. We recently demonstrated that the combination of illumination and facet-selective charge extraction can be used to synthesize a novel nanoscale morphology consisting of hollow copper nanoshells. A second research area in our lab is fluorescence microscopy at the single-particle and single-molecule levels to understand how heterogeneity in the size, shape, and surface chemistry of nanoscale materials affect their chemical reactivity. We use chemically activated fluorogenic probes to image active regions in semiconductor particles for photocatalytic transformations. Through this technique, we have developed new chemical insights into how oxygen vacancies enhance the photocatalytic activity of tungsten oxide and bismuth oxybromide photocatalysts for fuel-forming reactions including water oxidation and the reduction of carbon dioxide.