McKetta Department of Chemical Engineering and Texas Materials Institute, The University of Texas at Austin
Nanocrystal Inks and Nanowire Networks for Paper Solar Cells, Improved Batteries and Water Purification Membranes
Synthetic nanocrystal chemistry has evolved to produce a variety of new materials that are potentially useful in a range of applications addressing food, energy and water sustainability. This talk will present work using copper indium diselenide (CuInSe2) nanocrystals as printed semiconductor absorber layers on nanocellulose paper substrates. These solar cells are extremely lightweight and mechanically flexible—even foldable across the active area of the device—and inexpensive to manufacture. Although the materials are still being developed to produce more photocurrent, there are numerous voltage-driven devices, as needed for a ubiquitous internet of things (IoT) that can be powered by these paper solar cells with their existing level of performance, even using indoor lighting resources. Work will also be presented on high aspect ratio, crystalline silicon (Si) and germanium (Ge) nanowires for use as high energy storage capacity lithium and sodium ion battery electrodes and as porous fabric and aerogel networks as an emerging class of membrane filtration materials for water purification. In situ transmission electron microscopy (TEM) observations of Si and Ge nanowire undergoing lithiation/delithiation and sodiation/desodiation in real-time have provided a significant amount of insight about the potential and limitations of these materials for battery applications. In the case of the porous nanowire networks, the density of the nanowires can be tuned from relatively compact non-woven fabrics to very low density aerogels. The thermal, mechanical and filtration propertis of these nanowire networks, which derive from the unique properties of the nanowires and their collective interactions, will be discussed.