Thermoelectric materials transform temperature gradients to voltages and vise versa. Despite their many advantages, devices based on thermoelectric materials are used today only in a few applications, due to their low efficiency, which is described by the figure of merit ZT. Theoretical studies predict that scaling down these materials to the nanometric scale should enhance their efficiency partially due to a decrease in their lattice thermal conductivity. In this work we determine for the first time the lattice thermal conductivity of 40 nm bismuth (Bi) nanowires (NWs), i.e. NWs with a diameter comparable to the Fermi wavelength of charge carriers in this material. We find a surprisingly low lattice thermal conductivity of 0.13 ± 0.05 W K(-1) m(-1) at 77 K. A quantitative argument, which takes into account several unique properties of Bi, is given to explain this unusual finding.
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http://dx.doi.org/10.1088/0957-4484/23/49/495711 | DOI Listing |
J Am Chem Soc
January 2025
New Chemistry Unit, International Centre for Materials Science and School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Bangalore, Jakkur P.O. 560064, India.
Seeking new and efficient thermoelectric materials requires a detailed comprehension of chemical bonding and structure in solids at microscopic levels, which dictates their intriguing physical and chemical properties. Herein, we investigate the influence of local structural distortion on the thermoelectric properties of TlCuS, a layered metal sulfide featuring edge-shared Cu-S tetrahedra within CuS layers. While powder X-ray diffraction suggests average crystallographic symmetry with no distortion in CuS tetrahedra, the synchrotron X-ray pair distribution function experiment exposes concealed local symmetry breaking, with dynamic off-centering distortions of the CuS tetrahedra.
View Article and Find Full Text PDFSmall
January 2025
Center of Quantum Materials and Devices, College of Physics, Chongqing University, Chongqing, 401331, China.
Spin-orbit coupling (SOC) induced nontrivial bandgap and complex Fermi surface has been considered to be profitable for thermoelectrics, which, however, is generally appreciable only in heavy elements, thereby detrimental to practical application. In this study, the SOC-driven extraordinary thermoelectric performance in a light 2D material Fe₂S₂ is demonstrated via first-principles calculations. The abnormally strong SOC, induced by electron correlation through 3d orbitals polarization, significantly renormalizes the band structures, which opens the bandgap via Fe 3d orbitals inversion, exposes the second conduction valley with weak electron-phonon coupling, and aligns the energy of Fe 3d and S 3p orbitals with divergent momentum in valence band.
View Article and Find Full Text PDFMater Horiz
January 2025
State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing 211816, China.
Silver-based fast ionic conductors show promising potential in thermoelectric applications. Among these, AgS offers unique high plasticity but low electrical conductivity, whereas AgTe exhibits high intrinsic electrical conductivity yet faces limitations due to high thermal conductivity and poor plasticity. Developing a composite thermoelectric material that combines the benefits of both is therefore essential.
View Article and Find Full Text PDFInorg Chem
January 2025
Key Laboratory of Macromolecular Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an 710062, Shaanxi, P. R. China.
Many phosphor hosts, for example, nitrides and sulfides, often face challenges such as hydrolysis and oxidation, limiting their application in phosphor-converted white light-emitting diodes (pc-LEDs). In this study, we developed a highly humidity-resistant yellow-green-emitting phosphor BaSiNO:Ce (BSNO:Ce). The DFT calculations revealed a high Debye temperature (Θ = 1159 K), indicating a rigid crystal structure that contributes to the photoluminescence thermal quenching resistance of BSNO.
View Article and Find Full Text PDFSci Rep
January 2025
Mechanical Engineering, Stanford University, Stanford, CA, 94305, USA.
Triply periodic minimal surface (TPMS) metamaterials show promise for thermal management systems but are challenging to integrate into existing packaging with strict mechanical requirements. Composite TPMS lattices may offer more control over thermal and mechanical properties through material and geometric tuning. Here, we fabricate copper-plated, 3D-printed triply periodic minimal surface primitive lattices and evaluate their suitability for battery thermal management systems.
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