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Lead sulfide (PbS) is widely recognized as a promising n-type thermoelectric material for use in the middle-temperature range. Although it already exhibits favorable electronic and thermal properties, its thermoelectric performance could be further enhanced by addressing the disparity between the light and heavy bands in the conduction band, thereby optimizing electrical transport, and by modifying the strength of its chemical bonds to reduce lattice thermal conductivity. In this study, we demonstrate that introducing just small amounts of antimony (Sb) into PbS generates a unique combination of interstitial and substitutional doping that leads to a significant improvement in both directions. Substitutional doping enhances the degeneracy between the light and heavy bands, increasing carrier mobility. At the same time, interstitial doping introduces a new resonance state near the Fermi level, providing an additional channel for electron transport while boosting carrier concentration. These synergistic effects lead to a marked increase in the power factor of PbS, achieving an average power factor (PFavg) of 1.07 mW m−1 K−2 across the temperature range of 320–873 K. Moreover, Sb substitution for Pb induces a shift in the surrounding S atoms toward Sb, weakening their bonds with neighboring Pb atoms. This shift results in a coexistence of strong and weak chemical bonds, which effectively reduces lattice thermal conductivity. Additionally, the defect structures introduced by Sb doping effectively scatter phonons, further lowering lattice thermal conductivity. As a result, PbS doped with 0.5% Sb exhibits a figure of merit (ZT) of 0.73 at 873 K, which is approximately three times higher than that of undoped PbS. [ABSTRACT FROM AUTHOR]

Bi2Te3-based alloys are only commercial thermoelectric materials. While, currently, n-type Bi2Te 2. 7 Se 0. 3 -based alloys commonly have lower ZT values than those of p-type Bi 0. 5 Sb 1. 5 Te3 based alloys. In this paper, the influence of different amounts of dispersing honey on the thermoelectric performance of n-type Bi2Te 2. 7 Se 0. 3 alloys synthesized by the hydrothermal and hot-pressing methods was investigated. The carbon atoms contained in honey could increase lattice defects and grain boundary density effectively, and improved the Seebeck coefficient and suppress lattice thermal conductivity simultaneously. By adjusting the amount of honey, the maximum ZT value reached 0.82 at 423 K, which was approximately 65% higher than that of the pristine Bi2Te2.7Se0.3. [ABSTRACT FROM AUTHOR]

In this study, ceramic samples of Bi2Sr2Co2Oy + v wt% B2O3 (v = 0.0, 0.1, 0.2, 0.3, 0.4) were synthesized using the solid state reaction method, and the influence of B2O3 additive on their microstructure and thermoelectric properties were investigated. On one hand, the B2O3 additive acted as a sintering aid, enhancing carrier mobility. On the other hand, B2O3 dispersion served as a nano-second-phase, increasing hetero-interfaces and strengthen phonon scattering, thereby effectively suppressing lattice thermal conductivity. By dual optimization of both electric and thermal transport performance, the Bi2Sr2Co2Oy + 0.3 wt% B2O3 sample achieved a high ZT value (thermoelectric figure of merit) of 0.31 at 923 K, which was improved by approximately 33% compared with the pristine Bi2Sr2Co2Oy sample. [ABSTRACT FROM AUTHOR]

Bi2Te3-based alloys are currently the best room-temperature thermoelectric materials, and have been used widely in the field of thermoelectric refrigeration. Bi2Te3 ingots prepared by the zone-melting method provide convenience for large-scale commercial application. Currently, one trend is that the dimensionless thermoelectric figure-of-merit (ZT) value of the n-type Bi2Te2.7Se0.3 is slightly lower than that of the p-type Bi0.5Sb1.5Te3. In this paper, n-type Bi2Te2.7Se0.3 alloy ingots with large size were successfully prepared through the optimized zone-melting preparation process, and achieved a high ZT value of 1.16 at 360 K. This value is higher than all the n-type or p-type Bi2Te3-based ingots in current commercial applications. [ABSTRACT FROM AUTHOR]