Thermoelectric Performance of Single Phase p-Type Quaternary (PbTe)_0.65–x(PbSe)_0.35(PbS)_x Alloys

Abstract

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 toPbTe. 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 proved to decrease lattice thermal conductivity due to the larger atomic mass contrast between Sulphur and Tellurium, however, 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

“…The current samples exhibit lower κ latt than the single-phase Na-doped compounds (PbTe) 0.65 (PbS) 0.25 (PbSe) 0.1 24 and (PbTe) 0.9 (PbSe) 0.1 , 23 as well as Na-doped PbTe below 600 K, 34 and κ latt of our samples is comparable to that of the multiphase nanostructured compound Pb 0.985 Na 0.015 Se 0.1 S 0.25 Te 0.65 25 and the single-phase compound Pb 0.98 Na 0.02 Se 0.1 S 0.05 Te 0.85 . 24 The microscopy analysis of single-phase polycrystalline Pb chalcogenides (with similar composition to those in the current study) shows no significant microstructural changes with slight compositional variations; 35 thus, the significantly reduced κ latt in our single-phase compound can be attributed to enhanced phonon scattering arising from randomly distributed Se and S solute atoms in the matrix.…”

Manipulation of Band Degeneracy and Lattice Strain for Extraordinary PbTe Thermoelectrics

“…These approaches have been frequently proven to be successful for advancing thermoelectrics, especially in p-type IV-VI compounds [16,[39][40][41][42][43][44][45][46][47]. Manipulation of the energy offset between the light valence band (L) and the heavy valence band (Σ) via alloying enables charge carriers to be transported by many band valleys (band degeneracy) for an increase in σ without explicitly reducing S [48].…”

Effects of isovalent doping on the thermoelectric properties of environmentally-friendly phosphide Ag6Ge10P12

“…This approach has been established for many isovalent-element-doped thermoelectric materials. [21][22][23][24][25][26][27][28][29][30] In this study, we investigated the electrical and thermal transport properties of isovalent Cu-and Sn-doped Ag 6 Ge 10 P 12 . It was revealed that the lattice thermal conductivity of Ag 6 Ge 10 P 12 can be systematically reduced by substitution the isovalent elements Cu and Sn for Ag and Ge, respectively.…”