The electronic structure and thermoelectric（TE） properties of Mg2GexSn1-x（x = 0.25, 0.50, 0.75） solid solutions are investigated by first-principles calculations and semi-classical Boltzmann theory. The special qu...The electronic structure and thermoelectric（TE） properties of Mg2GexSn1-x（x = 0.25, 0.50, 0.75） solid solutions are investigated by first-principles calculations and semi-classical Boltzmann theory. The special quasi-random structure（SQS） is used to model the solid solutions, which can produce reasonable band gaps with respect to experimental results.The n-type solid solutions have an excellent thermoelectric performance with maximum zT values exceeding 2.0, where the combination of low lattice thermal conductivity and high power factor（PF） plays an important role. These values are higher than those of pure Mg2Sn and Mg2Ge. The p-type solid solutions are inferior to the n-type ones, mainly due to the much lower PF. The maximum zT value of 0.62 is predicted for p-type Mg2Ge（0.25）Sn（0.75） at 800K. The results suggest that the n-type Mg2GexSn1-x solid solutions are promising mid-temperature TE materials.展开更多
The electronic structure and thermoelectric（TE） properties of PbS_xTe_（1-x）（x = 0.25, 0.5, and 0.75） solid solution have been studied by combining the first-principles calculations and semi-classical Boltzmann t...The electronic structure and thermoelectric（TE） properties of PbS_xTe_（1-x）（x = 0.25, 0.5, and 0.75） solid solution have been studied by combining the first-principles calculations and semi-classical Boltzmann theory. The special quasirandom structure（SQS） method is used to model the solid solutions of PbS_xTe_（1-x）, which can produce reasonable electronic structures with respect to experimental results. The maximum zT value can reach 1.67 for p-type PbS0.75Te0.25 and 1.30 for PbS0.5Te0.5 at 800 K, respectively. The performance of p-type PbS_xTe_（1-x） is superior to the n-type ones, mainly attributed to the higher effective mass of the carriers. The z T values for PbS_xTe_（1-x） solid solutions are higher than that of pure Pb Te and Pb S, in which the combination of low thermal conductivity and high power factor play important roles.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.11647010)the Foundation from the Higher Education and High-quality and World-class Universities(Grant No.PY201611)
文摘The electronic structure and thermoelectric（TE） properties of Mg2GexSn1-x（x = 0.25, 0.50, 0.75） solid solutions are investigated by first-principles calculations and semi-classical Boltzmann theory. The special quasi-random structure（SQS） is used to model the solid solutions, which can produce reasonable band gaps with respect to experimental results.The n-type solid solutions have an excellent thermoelectric performance with maximum zT values exceeding 2.0, where the combination of low lattice thermal conductivity and high power factor（PF） plays an important role. These values are higher than those of pure Mg2Sn and Mg2Ge. The p-type solid solutions are inferior to the n-type ones, mainly due to the much lower PF. The maximum zT value of 0.62 is predicted for p-type Mg2Ge（0.25）Sn（0.75） at 800K. The results suggest that the n-type Mg2GexSn1-x solid solutions are promising mid-temperature TE materials.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11647010 and 11704020)the Higher Education and High-quality and World-class Universities(Grant No.PY201611)the Fund for Disciplines Construction from Beijing University of Chemical Technology(Grant No.XK1702)
文摘The electronic structure and thermoelectric（TE） properties of PbS_xTe_（1-x）（x = 0.25, 0.5, and 0.75） solid solution have been studied by combining the first-principles calculations and semi-classical Boltzmann theory. The special quasirandom structure（SQS） method is used to model the solid solutions of PbS_xTe_（1-x）, which can produce reasonable electronic structures with respect to experimental results. The maximum zT value can reach 1.67 for p-type PbS0.75Te0.25 and 1.30 for PbS0.5Te0.5 at 800 K, respectively. The performance of p-type PbS_xTe_（1-x） is superior to the n-type ones, mainly attributed to the higher effective mass of the carriers. The z T values for PbS_xTe_（1-x） solid solutions are higher than that of pure Pb Te and Pb S, in which the combination of low thermal conductivity and high power factor play important roles.
