California Institute of Technology

Yanzhong Pei

G Jeffrey Snyder

Heng Wang

Aaron LaLonde

The present invention discloses heavily doped PbSe with high thermoelectric performance. Thermoelectric property measurements disclosed herein indicated that PbSe is high zT material for mid-to-high temperature thermoelectric applications. At 850 K a peak zT&#x3e;1.3 was observed when n&#x2dc;1.0&#xd7;10cm. The present invention also discloses that a number of strategies used to improve zT of PbTe, such as alloying with other elements, nanostructuring and band modification may also be used to further improve zT in PbSe.

Heavily doped PbSe with high thermoelectric performance

The present invention teaches an effective mechanism for enhancing thermoelectric performance through additional conductive bands. Using heavily doped p-PbTe materials as an example, a quantitative explanation is disclosed, as to why and how these additional bands affect the figure of merit. A high zT of approaching 2 at high temperatures makes these simple, likely more stable (than nanostructured materials) and Tl-free materials excellent for thermoelectric applications.

High thermoelectric performance by convergence of bands in IV-VI semiconductors, heavily doped PbTe, and alloys/nanocomposites

The inventors demonstrate herein that homogeneous Ag-doped PbTe/AgTe composites exhibit high thermoelectric performance (&#x2dc;50% over La-doped composites) associated with an inherent temperature induced gradient in the doping concentration caused by the temperature-dependent solubility of Ag in the PbTe matrix. This method provides a new mechanism to achieve a higher thermoelectric efficiency afforded by a given material system, and is generally applicable to other thermoelectric materials.

Self-tuning of carrier concentration for high thermoelectric performance

The present invention demonstrates that weak scattering of carriers leads to a high mobility and therefore helps achieve low electric resistivity with high Seebeck coefficient for a thermoelectric material. The inventors demonstrate this effect by obtaining a thermoelectric figure of merit, zT, higher than 1.3 at high temperatures in n-type PbSe, because of the weak scattering of carriers in the conduction band as compared with that in the valence band. The invention further demonstrates favorable thermoelectric transport properties of n-type PbTeIwith carrier concentrations ranging from 5.8&#xd7;10-1.4&#xd7;10cm.

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Alhambra, CA, United States of America

Yanzhong Pei