Effects of Sn dopant on power factor of Tl8.67Sb1.33-xSnxTe6 nanoparticles

In this research work the thermoelectric and electrical performance of Sn doped Tellurium Telluride Tl8.67SnxSb1.33-xTe6 (x=0.61, 0.63, 0.65, 0.67, 0.68, 0.70), was studied. The samples were synthesized by melting method. By XRD and EDX analysis it has been confirmed that single phase tetragonal crystal structure with no any other impurities. The See beck co-efficient (thermo power) (S) shows increasing positive trend showing p-type semiconductor characteristics with whole temperature range from 300 to 550 K. At ambient temperature complex behavior of See beck coefficient for Sn doped compounds has been observed initially S decreasing with increase in Sn concentration i.e. x=0.65, and then S increases with increase in Sn contents up to x=0.70. In additional the electrical conductivity (σ) and the power factors have also shows the same complex behavior with the increase of Sn concentrations.. Telluride’s are narrow band-gap semiconductors, with all elements in common oxidation states, according to (Tl+ )9(Sb3+) (Te2- )6.It is found that the power factor is increases with Sn concentrations as well as increase in temperature range from 300-500 K.