Enhanced Thermoelectric Performance of PbTe Nanocomposites with Ag Nanoinclusions

Abstract

Nanocomposites have already been widely used to enhance thermoelectric performance since they exhibit exceptionally low lattice thermal conductivities. Further improvement is expected to arise from boosting the power factor and charge carrier relevant figure of merit ZT with nanoinclusions. Here we present that Ag nanoscale inclusions embedding in the n-PbTe can meet this requirement. The quantitative relationships between such nanostructures in PbTe and thermoelectric properties, using a versatile model including the details of geometry, electron–phonon interactions, quantization, and tunneling, showed that the Seebeck coefficient can be significantly enhanced due to interface potential barrier induced by Ag nanoinclusions. Additionally, it was found that high-concentration Ag nanoinclusions with 1–2 nm radius can effectively enhance the thermoelectric performance of PbTe through energy-selective carrier scattering, especially around room temperature. The power factor and charge carrier relevant figure of merit ZT can be elevated by at least 80% and 260%, respectively. These findings highlight effective strategies to nanostructuring for overcoming the high threshold to commercial application for cooling and power generation.