Enhancement of thermoelectric figure of merit in binary- phased La_0.3Ce_0.37Fe₃CoS₁₂-PbTe materials

Abstract

To enhance the Seebeck coefficient and reduce the thermal conductivity while maintaining a satisfied electrical conductivity, a disordered structure was introduced into the La_0.3Ce_0.37Fe₃CoSb₁₂ crystalline by adding a low-melting-point lead telluride (PbTe). The results suggest that the disordered structure created by the melted PbTe at 870 K can be partly preserved into the La_0.3Ce_0.37Fe₃CoSb₁₂ materials at room temperature. With the existence of the disordered structure the Seebeck coefficient at 773 K is increased from 143 μV⋅K^-1 to 265 μ VK^-1, while the thermal conductivity is reduced from 2.12 W⋅m^-1⋅K^-1 to 1.60 W⋅m^-1⋅K^-1, nevertheless the electrical conductivity is dropped from 78000 Ω^-1⋅m^-1 to 23500 Ω^-1⋅m^-1. A figure of merit of 0.95 at 773 K is observed for the material containing 40% PbTe.