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Date: Tuesday, July 8, 2014
Time: 11:00 am
Speaker: Eli Yablonovitch, UC Berkeley
Title: Regenerative Thermo-PhotoVoltaics, a New Opportunity in Radiative Science
Location: 67-3111 Chemla Room


Recent breakthroughs in the understanding of solar cells have led to new record efficiencies. Like all new scientific developments, there are repercussions that extend into new and unexpected areas. Serendipitously, the need for high internal reflectivity in the record- breaking solar cells has solved a 50-year-old-impasse that had prevented progress in thermo- photovoltaics. In thermo-photovoltaics, heat radiation is converted directly into electricity in photovoltaic cells; but the efficiency has not exceeded ~15%. By exploiting a black-body photon gas to recycle the thermal photons, efficiencies are projected to reach >50%, making thermo-photovoltaics competitive with mechanical heat engines to produce electricity. The only moving parts are photons. Nonetheless, a thermo-electric generator could possibly replace the internal combustion engine for charging hybrid vehicles.

Eli Yablonovitch is Director of the NSF Center for Energy Efficient Electronics Science (E3S), a multi-University Center based at Berkeley. After a career in industry and in Universities, he is now Professor of Electrical Engineering and Computer Sciences at UC Berkeley, where he holds the James & Katherine Lau Chair in Engineering. He contributed the 4(n squared) light-trapping factor to solar cells, which is used commercially in most solar panels world-wide. He introduced the benefit of strained quantum well lasers, an idea which is employed widely in most semiconductor lasers. He is regarded as a Father of the Photonic BandGap concept, and he coined the term "Photonic Crystal". Prof. Yablonovitch is a Fellow of the Optical Society of America, the IEEE, and the American Physical Society. He was elected a Member of the National Academy of Engineering, the National Academy of Sciences, the American Academy of Arts & Sciences, and as Foreign Member of the Royal Society of London. He has been awarded the Adolf Lomb Medal, the W. Streifer Scientific Achievement Award, the R.W. Wood Prize, the Julius Springer Prize, the IET Mountbatten Medal (UK), the IEEE Photonics Award, the Harvey Prize (Israel), and the Rank Prize (UK). He also has an honorary Ph.d. from the Royal Inst. of Tech., Stockholm Sweden, and from the Hong Kong Univ. of Sci. & Technology.