Quantum dots are nanometer-sized crystals with size-dependent properties that serve as intriguing building blocks for mesoscale materials. We control quantum dot synthesis, assembly, surface chemistry and defects to explore new regimes of charge transport, with the goal of producing a novel class of high-performance quantum dot solids for next-generation optoelectronic devices.
Solar-driven synthesis of chemical fuels like H2 and liquid hydrocarbons from water and carbon dioxide is an attractive route to the large-scale storage and distribution of renewable energy. Our group is developing new semiconductor materials and devices for the efficient, stable and cost-effective photoelectrochemical oxidation of water. Water oxidation is a major challenge for nascent photoelectrochemical solar fuels technologies.
Photoexcitation of plasmonic metal nanostructures produces strong surface fields and high densities of hot carriers that can be used in chemical sensing, single-molecule spectroscopy and photocatalysis. We fabricate precise assemblies of colloidal plasmonic nanocrystals to manipulate and study plasmonic photophysics and the mechanisms of plasmon-driven photochemistry.
Commercialization of thin-film solar cells based on earth-abundant, non-toxic light absorbers could further accelerate the global transition to solar electricity. Our group investigates high-risk, high-reward materials which possess an “Achilles’ heel,” that, if overcome, would clear a path to their commercial development. One such material is iron pyrite, FeS2. We use fundamental transport, spectroscopy, and device studies to understand the reason(s) for underperformance and to design fixes.
