High Pressure Synthesis and Electrical Properties of Ag_1-xPb₁₈SbTe₂₀

Thermoelectric materials Ag_1-xPb₁₈SbTe₂₀ (x=0, 0.3, 0.6) were synthesized by high pressure method.The composition dependent electrical properties were studied from room temperature to 500 ℃.The result of X-ray diffraction indicates that Ag_1-xPb₁₈SbTe₂₀ samples have the structure of NaCl crystal.As Ag content decreases, the lattice constant decreases.The measurement results of electrical properties show that the electrical conductivity of Ag_1-xPb₁₈SbTe₂₀ samples synthesized by high pressure is much higher than that of other preparing methods.The electrical conductivity increases with x, and its maximum value reaches 1 598.4 S/cm at room temperature for the Ag_0.4Pb₁₈SbTe₂₀ sample.As the temperature rises, Seebeck coefficient increases and electrical conductivity decreases.The maximum power factor reaches 1.97 mW/(m·K²) at 300 ℃ for the Ag_0.4Pb₁₈SbTe₂₀ sample.