Event Information |
Nanocolloquium: Peidong Yang - Nanowire Technology and Terawatt Challenge NANOCOLLOQUIUM 20: Peidong Yang - Nanowire Technology and Terawatt Challenge
Abstract
Semiconductor nanowires, by definition, typically have cross-sectional dimensions that can be tuned from 2–200 nm, with lengths spanning from hundreds of nanometers to millimeters. After more than a decade of research, nanowires can now be synthesized and assembled with specific compositions, heterojunctions and architectures. This has led to a host of nanowire photonic and electronic devices. Because of their unique structural, chemical and physical properties, these nanoscopic one-dimensional nanostructures can also play a significant role in terawatt energy conversion and storage. Currently the amount of energy required worldwide is on the scale of terawatts, and the percentage of renewable energy in the current energy portfolio is quite limited. Developing of cost-effective clean technology becomes imperative. I will show two examples from my group, approaching this problem in two different directions. The first relates to saving energy, by developing nanostructured silicon thermoelectrics to do waste heat recovery; and the second, to develop nanostructures for solar energy conversion, either directly to electricity or to liquid fuels through artificial photosynthesis.
We have discovered that the thermal conductivity of the silicon nanowires can be significantly reduced due to phonon scattering, pointing to a very promising approach to design better thermoelectrical materials. It is important to note that the engines that generate most of the world’s power typically operate at only 30–40 per cent efficiency, releasing roughly 15 terawatts of heat to the environment. If this “wasted heat” could be recycled, the impact globally would be enormous. This silicon nanowire thermoelectric work should have a significant impact in alternative energy generation.
Biography
Professor, B. A. Chemistry, University of Science and Technology in China (1993); Ph. D. Chemistry, Harvard University (1997); Postdoctoral Fellow, University of California, Santa Barbara (1997-1999); Camille and Henry Dreyfus New Faculty Award (1999); 3M Untenured Faculty Award (2000). Research Innovation Award (2001); Alfred P. Sloan Fellow (2001); NSF CAREER Award (2001); Hellman Family Faculty Award (2001); ACS ExxonMobil Solid State Chemistry Award (2001); Beckman Young Investigator Award (2002). MIT Tech. Review TR 100 (2003); ChevronTexaco Chair in Chemistry, Berkeley (2003); First Chairperson for American Chemical Society, Nanoscience subdivision (2003); Camille Dreyfus Teacher-Scholar Award (2004); Dupont Young Professor Award (2004), Julius Springer Prize for Applied Physics (2004), MRS Outstanding Young Investigator Award (2004), ACS Pure Chemistry Award (2005), University of Wisconsin McElvain Lectureship (2006), Chinese Academy of Science Molecular Science Forum Lectureship (2006), NSF A. T. Waterman Award (2007), Scientific American 50 Award (2008).
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