Bi和Ag掺杂对SnTe热电性能的影响OACSTPCD

SnTe has been widely studied as an alternative to PbTe because of its similar crystal structure and band structure to PbTe,the thermoelectric material with the best performance in the middle temperature region.Reducing the energy difference between heavy and valence bands and enlarging the band gap of SnTe are effective means to optimize the thermoelectric performance of SnTe.In this paper,by co-doping SnTe with Bi and Ag,the energy difference between heavy and valence bands is effectively reduced,the band gap is obviously increased,and the Sn1-2xBixAgxTe(x=0,0.01,0.02,0.03,0.04)samples with improved electric transport properties are obtained.Compared with undoped SnTe,the power factor of Sn1-2xBixAgxTe samples doped x=0.03 and 0.04 is significantly improved,and the maximum power factor of Sn0.94Bi0.03Ag0.03Te samples is 15.34 μW·cm-1·K-2,which is 12.9％higher than undoped SnTe.The maximum power factor of Sn0.92Bi0.04Ag0.04Te sample is 14.53 μW·cm-1·K-2.At the same time,Bi and Ag doping decreased the thermal conductivity of SnTe.In this study,the total thermal conductivity of Sn0.92Bi0.04Ag0.04Te samples is significantly lower than that of undoped SnTe,and the thermal conductivity of all samples gradually decreases with the increase of temperature.At 823 K,the total thermal conductivity of Sn0.92Bi0.04Ag0.04Te sample decreases to 3.073 W·m-1·K-1,and its ZT value increases to 0.387.It can be seen that the co-doping of Bi and Ag is an effective strategy to improve the thermoelectric performance of SnTe.