Extrapolation of Transport Properties and Figure of Merit of a Thermoelectric Material

Energies

H. Julian Goldsmid²  Jeff Sharp¹ 

[1]Marlow Industries, Inc. (Subsidiary of II-VI Incorporated) 10451 Vista Park Rd., Dallas, TX 75238, USA

[2] E-Mail:

[3]School of Physics, University of New South Wales, Sydney 2052, Australia

关键词: thermoelectric;    generation;    semiconductors;    energy conversion;    energy gap;    intrinsic conduction;    extrinsic conduction;   

DOI  :  10.3390/en8076451

来源: mdpi

【 摘 要 】

The accurate determination of the thermoelectric properties of a material becomes increasingly difficult as the temperature rises. However, it is the properties at elevated temperatures that are important if thermoelectric generator efficiency is to be improved. It is shown that the dimensionless figure of merit, ZT, might be expected to rise with temperature for a given material provided that minority carrier conduction can be avoided. It is, of course, also necessary that the material should remain stable over the whole operating range. We show that the prediction of high temperature properties in the extrinsic region is possible if the temperature dependence of carrier mobility and lattice thermal conductivity are known. Also, we show how the undesirable effects arising from mixed or intrinsic conduction can be calculated from the energy gap and the relative mobilities of the electrons and the positive holes. The processes involved are discussed in general terms and are illustrated for different systems. These comprise the bismuth telluride alloys, silicon-germanium alloys, magnesium-silicon-tin and higher manganese silicide.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.