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A1: Low temperature materials

Thermoelectric properties of Bi2(Te1-xSex)3 nanocrystalline prepared by high pressure sintering technique

Ping Zou, Gui-Ying Xu*, Song Wang
School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China*Corresponding author: Gui-Ying Xu

Bi2(Te1-xSex)3 (x=0,0.03,0.05,0.07,0.10)bulk materials were prepared by high pressure (6.0GPa) sintering (HPS) method at 673K. The HPS samples were then annealed for 36 hours in vacuum at 633K. The phase composition, morphology and thermoelectric (TE) properties were characterized. The samples consist of nanoparticles before and after annealing. These nanostructures can effectively decrease lattice thermal conductivities by enhancing the phonon scattering. The substitution of tellurium by selenium has significant impacts on the electrical and thermal transport properties of the Bi2(Te1-xSex)3 alloys. HPS together with annealing can improve the TE properties by increasing electrical transport properties and simultaneous decreasing the lattice thermal conductivity of the sample with nanostructures. A peak thermoelectric figure of merit (ZT) of 0.91 at 373K is achieved for the sample annealed with x=0.10, about 21% higher than that of n-type zone melting material, making these materials more attractive for commercial applications.