Abstract: In the past two decades, advances in nanoparticle synthetic methods have dramatically expanded the library of nanoparticles, and consequently, exquisitely tailored physicochemical properties, available for exploitation. Despite our ability to generate individual nanoscale blocks with various compositional, structural, morphological, and surface properties, our ability to combine these components into multiscale architectures capable of systems-level functionality is in its infancy. Colloidal gel formation via sol-gel methods represents a versatile strategy for achieving nanoparticle assembly into 3-D interconnected networks across a range of length scales from nanometer to meter while retaining the intrinsic properties of the initial nanoscale building blocks. The highly porous, three-dimensionally connected gel network maximizes contact with the environment, making nanoparticle gels well-suited for sensing and catalysis applications. Moreover, sol-gel methods are also amenable to thin film deposition and patterning.

The present talk will focus on the application of sol-gel methods (traditionally used for oxides) for the assembly of metal chalcogenide (sulfide, selenide, telluride) particles, enabling formation of quantum dot (QD) colloidal gels that retain the intrinsic size-dependent optoelectronic properties of the components. We will describe chemical, and recently developed electrochemical, approaches to quantum dot assembly, and discuss the effect of these approaches on the physical properties of the resultant gels. Finally, the promise of such architectures to address challenges in energy and the environment, including the development of photocatalysts for transformation of water to hydrogen fuels, and highly sensitive and selective sensors for gas-phase species, will be discussed.

Bio: Stephanie Brock attended the University of Washington and attended graduate school at U. C. Davis. She began a postdoctoral position at the University of Connecticut, then a tenure-track position in the Department of Chemistry at Wayne State University and was promoted to Associate Professor. She is a Fellow of the AAAS and the ACS and the recipient of an NSF-CAREER award. She also serves as an Associate Editor for the ACS journal Chemistry of Materials and is the Deputy Editor of the new gold open-access journal ACS Materials Au.