1960 年 29 巻 6 号 p. 363-370
For the purpose of obtaining superior thermoelectric materials, purification of Bi, Te and Bi2Te3 has been carried out.
Bismuth is purified by the method of alkali-treatment and zone melting in removing Cu, Ag and Pb.
For the purification of tellurium, vacuum distillation is very efficient to remove Cu, Ag and Pb.
Measured thermoelectric power a and resistivity of purified Bi2Te3 were α=235μV•deg-1, and p=1.16×10-3Ω•cm respectively.
The influence of addictive impurities on Bi2Te3 is examined. Tl, Li, Pb and Cd etc. are p-type and Cu, Ag, Se, Te, halogen and metal-halides etc. are n-type impurities.
The thermoelectric properties of PbTe, Sb2Te3, Bi2Te3-Sb2Te3 and Bi2Te3-Bi2Se3 solid solution are examined. The result shows that the solid solution of isomorphous compounds is suitable for the thermoelectric material.
By the use of (Bi-Sb)2Te3 p-type element and Bi2(Te-Se)3 n-type element thermojunctions, the temperature drop of 71.3 deg was attained with a temperature of hot junction of 30°C.