Thermoelectric Properties of n-Type Bi2Te3/PbSe0.5Te0.5 Segmented Thermoelectric Material

To investigate the effects of segmentation of thermoelectric materials on performance levels, n-type segmented Bi2Te3/PbSe0.5Te0.5 thermoelectric material was fabricated, and its output power was measured and compared with those of Bi2Te3 and PbSe0.5Te0.5. The two materials were bonded by diffusion bonding with a diffusion layer that was ∼18 μm thick. The electrical conductivity, Seebeck coefficient, and power factor of the segmented Bi2Te3/PbSe0.5Te0.5 sample were close to the average of the values for Bi2Te3 and PbSe0.5Te0.5. The output power of Bi2Te3 was higher than those of PbSe0.5Te0.5 and the segmented sample for small ΔT (300 K to 400 K and 300 K to 500 K), but that of the segmented sample was higher than those of Bi2Te3 and PbSe0.5Te0.5 when ΔT exceeded 300 K (300 K to 600 K and 300 K to 700 K). The output power of the segmented sample was about 15% and 73% higher than those of the Bi2Te3 and PbSe0.5Te0.5 samples, respectively, when ΔT was 400 K (300 K to 700 K). The efficiency of thermoelectric materials for large temperature differences can be enhanced by segmenting materials with high performance in different temperature ranges.