Pb
1-xSn
xTe solid-solutions (0_??_x_??_1) were prepared by the unidirectional solidification process with a rocking furnace. The obtained Pb
1-xSn
xTe solid-solutions, which were all p-type, were homogeneous without segregation. Pb
1-xSn
xTe solid-solutions (0_??_x_??_0.40) was characterized below 800K by its maximum figure-of-merit Z
max that shifted to high temperature with increasing x, while Pb
0.35Sn
0.65Te showed the monotonous increase of Z with increasing temperature. The high average figure-of-merit Z
av was exhibited by Pb
0.60Sn
0.40Te and Pb
0.35Sn
0.65Te at low and high temperatures, respectively. When the joined material of Pb
0.60Sn
0.40Te and Pb
0.35Sn
0.65Te, which is referred to as functionally graded material (FGM), is applied under the temperature gradient of 300-800K, the Z
av is 1.28×10
-3K
-1; this value is higher by 11 and 91% than the Z
av of the monolithic Pb
0.60Sn
0.40Te and Pb
0.35Sn
0.65Te. Thus the maximum conversion efficiency η
max of FGM reaches 11.37%, which is improved by 11 and 69% when compared with Pb
0.60Sn
0.40Te and Pb
0.35Sn
0.65Te, respectively. It is clarified that FGM can perform the high Z
av, leading to the high η
max.
View full abstract