Highly efficient bismuth telluride doped p‐type Pb0.13Ge0.87Te for thermoelectric applications

Bi 2 Te 3 doped p‐type Pb 0.13 Ge 0.87 Te samples were prepared by hot pressing. We report on very high power factor values of ∼30 μW/cm K 2 at 500 °C, as were determined from Seebeck coefficient and electrical resistivity measurements. From dilatometric characterization, the phase transition from the low temperature rhombohedral to the high temperature cubic NaCl structures, takes place at 373 °C. This transition is accompanied by a continuous and gradual change of the lattice parameters, as was observed by hot stage XRD, suggesting a good mechanical durability upon thermal cycling and operating in large thermal gradients. magnified image Rhombohedral distortion of the cubic NaCl structure of Pb 1– x Ge x Te upon cooling, characterized by changes in the interaxial angle α and the lattice parameter. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)