Thermoelectric properties of materials near the band crossing line in Mg2Sn Mg2Ge Mg2Si system
Abstract Thermoelectric properties of materials with compositions on and near the band crossing line connecting Mg2Sn0.765Ge0.22Sb0.015 and Mg2Sn0.685Si0.3Sb0.015 in the Mg2Sn Mg2Ge Mg2Si system are investigated. Although ZTs are very similar, power factors are different. On the line, the power factor decreases from Mg2Sn0.765Ge0.22Sb0.015 to Mg2Sn0.685Si0.3Sb0.015, and off the line, the power factor also decreases. The output power and energy conversion efficiency are calculated using engineering power factor (PF)eng and figure of merit (ZT)eng. It is shown that although similar energy conversion efficiency of ~11% could be achieved for all compositions studied, the output power are different, increasing from ~9.1 W cm 2 for Mg2Sn0.685Si0.3Sb0.015 to ~10.3 W cm 2 for Mg2Sn0.765Ge0.22Sb0.015, due to the different power factors.