The Sadtler research group uses light to image and control chemical transformations in inorganic nanostructures.
Imaging heterogeneity in the reactivity of semiconductor nanocrystals. Unlike molecular synthesis in which a single desired product can often be isolated, the synthesis of nanoscale particles inherently produces a distribution of sizes and shapes. We make measurements one particle at a time to understand how this heterogeneity impacts the chemical reactivity of colloidal semiconductor nanocrystals. Currently, we are using super-resolution fluorescence microscopy and chemically activated fluorogenic probes to map spatial variations in the photocatalytic activity of semiconductor particles. These studies have provided new insights into how oxygen vacancy clusters enhance the activity of metal oxide semiconductors for fuel-forming reactions We are also imaging solid-state transformations in lead halide perovskite nanocrystals to determine how heterogeneity in their nucleation and growth kinetics will affect the performance of solar cells and light-emitting diodes.
Light-directed growth of inorganic nanostructures. 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. We are designing adaptive inorganic materials that adjust their growth in response to illumination to synthesize complex nanostructures and metastable materials that cannot be made by traditional synthetic methods.
Defects in nanoscale crystals. While defects in crystalline solids are often considered to be detrimental for applications in energy conversion and storage, the controlled introduction of defects can both regulate the growth of nanoscale crystals and enhance their catalytic activity. We have shown how the controlled introduction of twin defects in ternary silver halide nanocrystals can be used to regulate their shape.
