Search

Here, a typical microwave hydrothermal-assisted synthesis method is utilized to fabricate Co/Sn co-doped Cu 3 SbSe 4 materials. Experimental results demonstrate that the formation of a nanoscale Co 9 Se 8 phase occurs when the solid solubility of Co is exceeded. This phase effectively enhances phonon scattering at the grain boundary's high-density dislocation region, leading to a significant reduction in lattice thermal conductivity. Simultaneously, the interface between Co 9 Se 8 and Cu 3 SbSe 4 exhibits an energy filtering effect, resulting in an improved Seebeck coefficient. The maximum zT value of 0.62 is achieved in the Cu 3 Sb 0.96 Co 0.04 Se 4 sample. To further regulate the carrier concentration, Sn atoms are introduced, leading to peak power factor and zT values of 865.98 μW·m−1·K−2 and 0.72, respectively. The incorporation of Co and Sn doping contributes to the enhancement of mechanical properties by reinforcing covalent bonds. Mechanical property testing of the materials indicates an improvement in mechanical performance upon doping with Co and Sn. This study provides valuable insights into the in-situ introduction of a second phase through element doping, thereby enhancing the comprehensive thermoelectric properties of Cu 3 SbSe 4 -based materials. Moreover, it establishes an experimental foundation for subsequent investigations into the materials' mechanical properties. • Co 9 Se 8 phase effectively enhances phonon scattering at the grain boundary region. • The energy filtering effect results in an improved Seebeck coefficient. • Sn doping was further performed to optimize the carrier concentration. • The mechanical properties enhanced by the strengthen of the covalent bonds. • The zT max of the Co/Sn co-doped sample was 0.72 at 673 K. [ABSTRACT FROM AUTHOR]

Cu 3 SbSe 4 , a promising p-type thermoelectric (TE) material consisting of earth-abundant, nontoxic, cost-efficient and eco-friendly constituent elements. However, its low TE performance is relatively poor because of the low carrier concentration and mobility. Herein, we synergistically optimize the electrical and thermal transport properties of Cu 3 SbSe 4 via embedding nanoscale Sb 2 Se 3. The Sb 2 Se 3 nanophase markedly increases the carrier concentration and carrier effective mass simultaneously, resulting in a higher power factor of ∼1100 μW m−1 K−2. Surprisingly, Sb 2 Se 3 nanophase induces high-density phase boundaries and dislocations, which significantly depress the lattice thermal conductivity. The multiple effects of incorporation of Sb 2 Se 3 boost Cu 3 SbSe 4 to an outstanding ZT value of ∼0.86 at 673 K for Cu 3 SbSe 4 +1.5 mol% Sb 2 Se 3 composite, which is ∼1.70 times as high as that of pristine Cu 3 SbSe 4. It is highly remarkable that Cu 3 SbSe 4 with nanoscale Sb 2 Se 3 is mechanically robust, showing the Vickers hardness (H v) and fracture toughness (K IC) of ∼2.54 GPa and ∼0.73 ± 0.02 MPa m½, which are ∼20% and ∼12% higher than those of pristine Cu 3 SbSe 4 , respectively. This work provides guidance for enhancing the comprehensive TE and mechanical properties of the copper-based chalcogenides by embedding nanophases. The thermoelectric and mechanical properties of Cu 3 SbSe 4 are synergistically optimized via embedding nanoscale Sb 2 Se 3. The enhanced thermoelectric performance due to the increased carrier concentration and depressed lattice thermal conductivity, the improved mechanical performance derived from the dispersion strengthening of Sb 2 Se 3 nanophases. Therefore, the Sb 2 Se 3 composited Cu 3 SbSe 4 exhibits great potential in application. [Display omitted] • The Sb 2 Se 3 nanophases markedly increase the n and m∗of Cu 3 SbSe 4 , resulting in a higher power factor of ∼1100 μW m−1 K−2. • Sb 2 Se 3 nanophases induce high-density phase boundaries and dislocations to significantly depress the κ lat. • The multiple effects of incorporation of Sb 2 Se 3 boost Cu 3 SbSe 4 to an outstanding ZT value of ∼0.86 at 673 K. • Cu 3 SbSe 4 with nanoscale Sb 2 Se 3 is mechanically robust, showing H v and K IC of ∼2.54 GPa and ∼0.73 ± 0.02 MPa m½, respectively. [ABSTRACT FROM AUTHOR]

Cu 3 SbSe 4 , consisting of earth-abundant and inexpensive elements, is a promising p-type thermoelectric (TE) material. However, its thermoelectric performance is low in comparison with typical Pb-based materials. Here, we tune Ag content to optimize synergistically electrical and thermal transport properties for achieving high TE performance of Bi-doped Cu 3 SbSe 4 materials. Dual-incorporation of Bi and Ag spontaneously generates multiple secondary phases involving CuSe and AgSbSe 2. The multiscale defects including point defects, dislocations, nanoprecipitates and grain boundaries can enhance phonon scattering, thereby obtaining a low thermal conductivity (κ) of ~ 0.67 W m−1 K−1 at 673 K. The carrier concentration is improved due to the enhanced Cu vacancies caused by softening of Cu 3d–Se 4p bond after Ag doping, leading to the obviously increased electrical conductivity (σ). Meanwhile, the heavy element dopants (Bi and Ag) can modify the band structure to enhance Seebeck coefficient (S) by enlarging band gap (E g) and increasing carrier effective mass (m *). The simultaneously enhanced σ and S result in a large power factor (S 2 σ) of ~1200 μW m−1 K−2 at 673 K. Consequently, a maximum ZT of ~1.18 (~136% higher than that of pristine Cu 3 SbSe 4) at 673 K and an averaged ZT of ~ 0.51 at 300–673 K are achieved for Cu 2.85 Ag 0.15 Sb 0.985 Bi 0.015 Se 4 sample due to a low κ and a high S 2 σ. This work offers a referential strategy to improve the comprehensive TE performance by dual-incorporation with isovalent heavy element doping for the diamond-like materials. • Cu 3 SbSe 4 -based materials show excellent TE properties through synergistically optimizing σ and κ lat with Bi and Ag co-doping. • The improved σ by the increased n , and S by the large m * and enlarged E g , yielding a high S 2 σ of ~ 1200 μW m−1 K−2. • Defects including point defects, dislocations, nanoprecipitates and grain boundaries, resulting in a low κ of ~ 0.67 W m−1 K−1. • A maximum ZT of ~ 1.18 at 673 K and averaged ZT of ~ 0.51 at 300–673 K are obtained for Cu 2.85 Ag 0.15 Sb 0.985 Bi 0.015 Se 4 sample. [ABSTRACT FROM AUTHOR]

Cu3SbSe4 is a potential p-type thermoelectric material, distinguished by its earth-abundant, inexpensive, innocuous, and environmentally friendly components. Nonetheless, the thermoelectric performance is poor and remains subpar. Herein, the electrical and thermal transport properties of Cu3SbSe4 were synergistically optimized by S alloying. Firstly, S alloying widened the band gap, effectively alleviating the bipolar effect. Additionally, the substitution of S in the lattice significantly increased the carrier effective mass, leading to a large Seebeck coefficient of ~730 μVK−1. Moreover, S alloying yielded point defect and Umklapp scattering to significantly depress the lattice thermal conductivity, and thus brought about an ultralow κlat ~0.50 Wm−1K−1 at 673 K in the solid solution. Consequently, multiple effects induced by S alloying enhanced the thermoelectric performance of the Cu3SbSe4-Cu3SbS4 solid solution, resulting in a maximum ZT value of ~0.72 at 673 K for the Cu3SbSe2.8S1.2 sample, which was ~44% higher than that of pristine Cu3SbSe4. This work offers direction on improving the comprehensive TE in solid solutions via elemental alloying. [ABSTRACT FROM AUTHOR]

Cu 3 SbSe 4 is a promising Te-free p-type thermoelectric material, characterized by earth-abundant, low-cost, and environmentally friendly constituents. Nonetheless, its thermoelectric performance is poor due to its extremely low electrical conductivity (deriving from the low carrier concentration) and high lattice thermal conductivity. Herein, we report a high-performance Cu 3 SbSe 4 -based material by compositing LaCl3 and introducing multiscale structure. The LaCl 3 -composted Cu 3 SbSe 4 forms heterojunctions that facilitate charge accumulation at the interfaces. The redistribution of electrons between the two materials increases the electrical conductivity without damaging the Seebeck coefficient, and thereby significantly improving the power factor to ∼1150 μWm−1K−2 for Cu 3 SbSe 4 -based bulk. Furthermore, the hierarchical architecture defects are induced by LaCl 3 compositing, yielding a minimum κ lat of ∼0.68 Wm−1K−1 at 673 K. As a consequence, a maximum ZT value of ∼0.90 at 673 K is achieved in the Cu 3 SbSe 4 +2 mol% LaCl 3 sample, representing an 80 % improvement compared to the pristine Cu 3 SbSe 4. [Display omitted] • A high-performance Cu 3 SbSe 4 -based material is obtained by compositing LaCl3 and introducing hierarchical architecture. • LaCl 3 compositing induce the formation of phase interfaces, thus synergistically increasing σ and suppressing κ lat. • Hierarchical architecture defects involving point defects, second phase, dislocations, grain boundaries and phase interfaces decrease κ lat. • LaCl 3 compositing boost Cu 3 SbSe 4 to an outstanding ZT value ∼0.90 at 673 K. [ABSTRACT FROM AUTHOR]

Developing cost‐effective and high‐performance thermoelectric (TE) materials to assemble efficient TE devices presents a multitude of challenges and opportunities. Cu3SbSe4 is a promising p‐type TE material based on relatively earth abundant elements. However, the challenge lies in its poor electrical conductivity. Herein, an efficient and scalable solution‐based approach is developed to synthesize high‐quality Cu3SbSe4 nanocrystals doped with Pb at the Sb site. After ligand displacement and annealing treatments, the dried powders are consolidated into dense pellets, and their TE properties are investigated. Pb doping effectively increases the charge carrier concentration, resulting in a significant increase in electrical conductivity, while the Seebeck coefficients remain consistently high. The calculated band structure shows that Pb doping induces band convergence, thereby increasing the effective mass. Furthermore, the large ionic radius of Pb2+ results in the generation of additional point and plane defects and interphases, dramatically enhancing phonon scattering, which significantly decreases the lattice thermal conductivity at high temperatures. Overall, a maximum figure of merit (zTmax) ≈ 0.85 at 653 K is obtained in Cu3Sb0.97Pb0.03Se4. This represents a 1.6‐fold increase compared to the undoped sample and exceeds most doped Cu3SbSe4‐based materials produced by solid‐state, demonstrating advantages of versatility and cost‐effectiveness using a solution‐based technology. [ABSTRACT FROM AUTHOR]

Large-scale Sn and/or S doped Cu3Sb1−xSnxSe4−ySy (x = 0.02, 0.04, 0.06 and 0.10; y = 0, 0.5) nanoparticles were first prepared through a low-temperature co-precipitation route. The effects of Sn doping on the thermoelectric properties of the Cu3SbSe4-based materials were explored. Due to the improved power factor from optimizing the carrier concentration and the reduced lattice thermal conductivity from enhanced phonon scattering at the grain interfaces, the maximum thermoelectric figure of merit, ZTmax, obtained here reached 1.1 for the co-doped Cu3Sb0.94Sn0.06Se3.5S0.5 material, which is the largest value reported for Cu3SbSe4-based materials. [ABSTRACT FROM AUTHOR]