Research

Our research is focused on fundamental problems in nanoscience and how they impact optoelectronic applications of nanoscale materials. Our approach integrates the design and synthesis of novel nanomaterials with detailed characterization in order to reveal how such materials interact with light. The group welcomes a broad spectrum of scientists, with interests ranging from synthetic chemistry to electron microscopy to femtosecond spectroscopy.

One of the defining themes in nanoscience is the control of physical properties of a material (such as its electronic structure) through solution-phase synthesis that produces nanostructures of well-defined composition, size, and shape. Our synthetic efforts are directed at creating complex nanomaterials that incorporate the properties necessary for optoelectronic applications, such as optimized light absorption and spatial separation of photoexcited charges. We use advanced electron microscopy techniques to characterize structure and composition of novel nanomaterials at the atomic level.

Time-resolved electronic spectroscopy allows us to directly probe the behavior of excited electrons and holes created when a material absorbs light. Events such as charge separation, transfer, recombination, and trapping determine the efficiency of photon energy conversion. We are interested in mapping out the dynamics of such events to understand how to improve the design of next generation nanomaterials. Using ultrafast spectroscopic techniques and analytical or numerical modeling, our group investigates the behavior of photoexcited charge carriers in colloidal semiconductor nanocrystals and how these behaviors are influenced by factors such as the nanocrystal material, size, shape, and surface chemistry.