Functionally Graded Bi2Te3 based material for above ambient temperature application

This study is concerned with the preparation of Bi_0.4Sb_1.6Te₃ functionally graded (FG) samples by a powder metallurgical approach for above ambient temperature applications. The FG sample is based on two components with different carrier concentration. The first is designed for a maximal figure of merit at room temperature, the second, doped with Pb, is meant for operation at higher temperatures. The transport properties of the two components of the FG sample, namely the Seebeck coefficient and electrical resistivity, have been determined from room temperature up to 550 K. The preparation of FG samples, their chemical stability and their transport properties over this temperatures range were examined and will be discussed.