Tailoring the thermoelectric properties of Pb1-xSmxTe nanostructures via Sm doping

n this research, stoichiometric Pb1-xSmxTe (x = 0, 0.02, 0.04, 0.06, 0.08) nanostructures were synthesized using the hydrothermal technique. The synthesized nanostructures were examined using X-ray diffraction, Raman spectroscopy, scanning and high-resolution transmission electron microscope and photoluminescence spectroscope. The results revealed that the samples were crystallized mainly in a cubic phase characterizing the PbTe compounds. However, the samples containing Sm content above x ≥ 0.06 exhibited small minor peaks correspond to the Pb phase. The PL spectra show a strong quantum confinement effectand exhibit a strong peak around 400 nm at room temperature that might be ascribed to the high level transition in the PbTe semiconductor. The thermoelectric measurements verified the domination of p-type semiconducting behavior. The reduction in the thermal conductivity through nanostructuring gives a high ZT of 0.7 at 398 K when Sm content reaches x = 0.06. The value is comparable to that of previously reported best PbTe-based thermoelectric materials.