Effect of TeI4 Content on Thermoelectric Properties of N-Type Bi2(Te,Se)3 Materials Prepared by Spark Plasma Sintering

The n-type Bi2(Te,Se)3 thermoelectric materials doped with different contents of TeI4 were fabricated through the spark plasma sintering (SPS) technique at 693K under a pressure of 60MPa. The sintered materials were rather dense and showed preferred grain orientation. Electrical conductivity (s), Seebeck coefficient (a), and thermal conductivity (k) were measured in the temperature range of 300-500K. The optimal figure of merit ZT (ZT=a2sT/k) of the sintered material in the direction perpendicular to the pressing direction showed a value of 0.75 for the sample containing 0.14wt% TeI4.