Thermoelectric performance of single phase p-type quaternary (PbTe)0.65–x(PbSe)0.35(PbS)x alloys

Recently, the quaternary system PbTe−PbSe−PbS has been shown to provide high thermoelectric efficiency, zT. The intent of this research is to investigate the thermoelectric properties of Na-doped pseudoternary (PbTe)0.65−x(PbSe)0.35(PbS)x with a high ratio of PbS to PbTe. The addition of a large concentration of PbSe increases the solubility limit of PbS in PbTe, allowing all samples to behave as solid solutions with a high concentration of PbS. This is proven to decrease lattice thermal conductivity due to the larger atomic mass contrast between sulfur and tellurium; however, it simultaneously causes a decrease in the Seebeck coefficient due to a larger band offset, so a high concentration of PbS shows no improvement in zT, with a maximum of ∼1.4 in the x = 0, 0.05, and 0.10 samples

Thermoelectric Performance of Single-Phase Tellurium-Reduced Quaternary (PbTe)(0.55)(PbS)(0.1)(PbSe)(0.35)

Lead chalcogenide quaternary systems have been shown to provide high thermoelectric (TE) efficiency superior to those of binary and ternary lead chalcogenides, arising from both altered electronic band structures and a reduction in lattice thermal conductivity. Here, we have synthesized single-phase samples of the quaternary compound (PbTe)0.55(PbS)0.1(PbSe)0.35 doped with Na and characterized their TE properties. We show that the dopant solubility is limited to 1 at. %. A very low lattice thermal conductivity of ∼0.6 W m–1 K–1 at 850 K is achieved at all dopant concentrations because of phonon scattering from point defects associated with solute atoms with high contrast atomic mass. As a result, a high TE figure of merit of approximately 1.5 is achieved at 823 K in heavily doped samples. Moreover, the figure of merit is greater than 1 over a wide temperature range above 675 K

Thermoelectric Performance Study of Cost-Effective Lead Chalcogenides

Global warming and resource management is steadily becoming a more pressing world issue. The use of renewable energy is a solution to many of the world’s problems and if a useful renewable energy source is found, its application would potentially be immediate and widespread across the world. One of the biggest energy sources that could be harnessed is waste heat, which makes up around 70 per cent of the total energy produced by major industry in developed countries like the USA. Thermoelectric devices directly convert heat into electricity, making thermoelectric materials a promising research area for waste heat recovery. There are many advantages to solid state thermoelectric devices, such as requiring almost no maintenance, being reliable and they can be used in a small scale such as on space missions or on larger applications like industrial blast furnaces. Anywhere that there is waste heat, thermoelectric devices can be used to harness the energy and improve efficiency