Temperature Gradient And Material Components Impact On Thermoelectric Conversion Performance Of Semiconductor Material

Thermoelectric transition element is the core part of thermoelectric generator by using seebeck effect of semiconductor components to transfer the electric energy with the thermal energy, the high low of the conversion efficiency directly effect the performance of the thermoelectric generator.So, this paper study on the relationship of material composition and thermoelectric properties in the high temperature phase and the low temperature phase, designed the thermoelectric element with three segment which compose with GeSi materials, PbTe materials and Bi₂Te₃ materials.We found experimentally that in the case of doping concentration equal, the temperature range between 200⁷00K, and the content of Si is about 60%(when x=0.64), the thermal conductivity of the sample is lower.But the sample that the content of Si is between 60%⁸0% have better seebeck coefficient which in the high temperature region.Research shows that when grinding and hot pressing the PbTe materials, the N type impurities such as O and S are introduced.The concentration of the P type carrier (the hole) decreased, the concentration of the N type carrier (the electron) increased.The sample have higher thermoelectric merit figure after ball milling.The thermoelectric element with three segment which compose with GeSi materials, PbTe materials and Bi₂Te₃ materials have been taken theoretical design in this paper, determined that when the hot side temperature is 1073K, the cold side temperature is 323K, and the total length of the element is 20mm, the prime length of the N-type GeSi materials is 17.689mm, the prime length of the N-type PbTe materials is 1.428mm, the prime length of the N-type Bi₂Te₃ materials is 0.883mm; the prime length of the P-type GeSi materials is 17.025mm, the prime length of the P-type PbTe materials is 1.876mm, the prime length of the P-type Bi₂Te₃ materials is 1.099mm the thermoelectric conversion efficiency is 6.71%, and the theory dimensionless optimal value close to 0.41.Power generation efficiency and availability are one of the key task projects in the new clean (energy ) field which domestic and overseas researched at present.In order to enlarge the application range, this article developed the thermoelectric element with three segment that compose with GeSi materials, PbTe materials and Bi₂Te₃ materials which suitable for 800℃to room temperature, provided the theoretical and experimental foundation for developing high efficiency thermoelectric generator.