분할접합비에 따른 (Pb,Sn)Te/(Bi,Sb)2Te3 경사기능소자의 열전발전특성

Abstract

0.5 at% Na2Te-doped (Pb0.7Sn0.3)Te and (Bi0.2Sb0.8)2Te3 powders were fabricated by mechanical alloying process. 0.5 at% Na2Te-doped (Pb0.7Sn0.3)Te powders were charged at one end of mold and (Bi0.2Sb0.8)2Te3 powders were charged at the other end of a mold. Then these powders wer hot-pressed to form p-type (Pb0.7Sn0.3)Te/(Bi0.2Sb0.8)2Te3 functional gradient materials with the segment ratios (the ratio of (Pb0.7Sn0.3)Te to (Bi0.2Sb0.8)2Te3) of 1:2, 1:1, and 2:1. Power generation characteristics of the (Pb0.7Sn0.3)Te/(Bi0.2Sb0.8)2Te3 were measured. When the temperature difference ΔT at both ends of the specimen was larger than 300℃, the (Pb0.7Sn0.3)Te/(Bi0.2Sb0.8)2Te3 with the segment ratios of 1:2 and 1:1 exhibited larger output power than those the (Bi0.2Sb0.8)2Te3 and 0.5 at% Na2Te-doped (Pb0.7Sn0.3)Te alloys. The maximum output power of the (Pb0.7Sn0.3)Te/(Bi0.2Sb0.8)2Te3 predicted with the measured Seebeck coefficient and the estimated electrical resistivity was in good agreement with the measured maximum output power.