When 3:30 PM - 5:00 PM Jan 18, 2013
Where 1670 CSE Building
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Solar and Thermoelectric Energy Conversion using Earth-Abundant Semiconductor Nanomaterials

Song Jin
Department of Chemistry, University of Wisconsin-Madison

The scale of renewable energy challenge not only calls for highly efficient technologies but also abundant, inexpensive, and robust materials. Nanomaterials such as one-dimensional (1D) nanowires can help to mitigate the poor properties of earth-abundant semiconductors to enhance solar energy conversion. We first discuss rational synthesis of nanowire materials of earth-abundant semiconductors, such as hematite (a-Fe2O3) and pyrite (FeS2), often using screw dislocation-driven nanowire growth. The photoelectrochemical (PEC) and photovoltaic (PV) properties are evaluated and the fundamental challenges facing these materials investigated. Various doping and nanostructuring strategies using 3D hierarchical nanocomposites are further developed to overcome the conflicting requirements by light harvesting and carrier collection.

In the second half, I will discuss the enhancement of thermoelectric properties of earth-abundant semiconducting silicides using nanowires and bulk nanostructures.   We have developed methods to synthesize nanowires of many silicides, including semiconducting higher manganese silicides (HMS, MnSi1.75) promising for thermoelectric applications and magnetic silicides for spintronics. Reduced thermal conductivity and potentially enhanced thermoelectric properties in HMS nanowires are found and strategies to form bulk nanostructures of HMS are developed.

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