Yuping He (SIMES Special Seminar)

Date/Time
Date(s) - Dec 2 2014
3:00 PM - 4:00 PM

Location
Room 335, McCullough Building

Category(ies)


Modeling and Ab initio Calculation of Transport Properties in Thermoelectric and

Photovoltaic Materials

Yuping He

University of California, Davis

 The Earth receives the part of the Sun energy in the form of “light” and “heat” at a rate of ~1400 Watt/m2/second. Exploiting the photovoltaic (PV) effect is a means to convert “light” into electrical power, while exploiting the thermoelectric (TE) effect is a suitable way to convert “heat” into electrical power. The integration of efficient PV and TE materials is a promising strategy to increase the efficiency of solar energy harvesting by reducing possible energy losses in PV cells; hence predicting and synthesizing promising PV-TE materials are research topics of great interest. We present calculations of the transport properties of thermoelectric Si-based clathrates [1,2] and solar hybrid organic/inorganic perovskites [3], as obtained from ab initio calculations and models, where all input parameters were derived from first principles. We elucidated the physical mechanisms responsible for the measured low thermal conductivity in Si-based clathrates [1] and predicted their electronic properties, mobilities and potential applications for photovoltaics, which were later confirmed experimentally [2]. We also predicted that by appropriately tuning the carrier concentration, the thermoelectric figure of merit of Sn and Pb based perovskites may reach values ranging between 1 and 2, which could possibly be further increased by optimizing the lattice thermal conductivity through engineering perovskite superlattices. Hence solar perovskites could be promising materials for thermoelectric applications as well.

Work supported by DOE/BES grant No. DE-FG0206ER46262.

[1] Y. He and G. Galli, Nano. Lett. 14, 2920 (2014)

[2] Y. He, F. Sui, S. M. Kauzlarich and G. Galli, Energy Environ. Sci. 7, 2386 (2014)

[3] Y. He and G. Galli, Chem. Mat. 26. 5394-5400 (2014)