Thermoelectric materials, which can generate electricity from waste heat or be used as solid-state Peltier coolers, could play an important role in a global sustainable energy solution. Such a development is contingent upon identifying materials with higher thermoelectric efficiency, which is a challenge owing to the conflicting combination of material traits that are required. Nevertheless, because of modern synthesis and characterization techniques, particularly regarding nanoscale materials, a new era of complex thermoelectric materials is approaching. Several new classes of compounds have been discovered which show enticingly high efficiencies. By reviewing recent advances in the field, we discuss the most promising strategies that can help guide the development of revolutionary thermoelectric materials: (a) quantum confinement of electrons to enhance thermopower (Seebeck coefficient), (b) low lattice thermal conductivity through structural complexity on various length scales, and (c) substructure approaches which separates the 'electron-crystal' from the 'phonon-glass'. Finally, we briefly discuss the integration of new thermoelectric materials into devices and the challenges of thermoelectric measurements.

Engineering semiconductor devices requires an understanding of charge carrier mobility. Typically mobilities are estimated using measurements of the Hall effect and electrical resistivity. Such measurements are routinely performed at room temperature and below in materials with mobilities greater than 1cm 2 /Vs. With the availability of combined Seebeck coefficient and electrical resistivity measurement systems, it is now easy to measure the weighted mobility (electron mobility weighted by the density of electronic states). Here we introduce a simple method to calculate the weighted mobility from combined Seebeck coefficient and electrical resistivity measurements that gives good results at room temperature and above, and for mobilities as low as 10 −3 cm 2 /Vs.

The thermoelectric device ZT is calculated using a simple spreadsheet calculator.

No abstract

tion. -Single crystals of the title compound are synthesized from mixtures of Yb, Mn, and Sb in a Sn flux (1100°C, 1 h). The samples are characterized by thermal conductivity, Seebeck coefficient, resistivity, and Hall effect measurements. This compound achieves quadrupled efficiency and virtually doubled figure of merit over the current state-of-the-art thermoelectric material, SiGe, thus making it superior for thermoelectric applications in segmented devices. Yb14MnSb11 represents the first complex Zintl phase with substantially higher figure of merit and efficiency than any other competing materials, opening a new class of thermoelectric compounds. -(BROWN, S. R.; KAUZLARICH*, S. M.; GASCOIN, F.; SNYDER, G.