(703a) Terahertz Spectroscopy: Probing Carrier Dynamics in Nanomaterials On Sub-Picosecond Time Scales

There is currently a world wide effort to make use of advances
in nanotechnology to design next generation solar cells that could make
economical solar energy a reality. One strategy pursued actively is using
nanowires, nanotubes or nanorods in solar cells as efficient conduits for
electron transport and extraction. Ultrashort far-infrared laser pulses are an
ideal probe of free carriers in these nanomaterials capable of resolving
carrier dynamics on femtosecond time scales. In this presentation new results
obtained with time-resolved terahertz spectroscopy will be presented revealing
why TiO₂ nanotubes, used to improve electron transport in dye
sensitized solar cells, are not yet significantly outperforming nanoparticle
films and how they potentially could. Far-infrared laser spectroscopy could
also supply unique information addressing core challenges facing several other
promising renewable energy and micro-electronic technologies. Some of these
future directions will be discussed briefly.