Previous first-principles calculations have failed to reproduce many of the key thermoelectric features of FeVAl, e.g. the maximum values of the Seebeck coefficient S and its asymmetry with respect to the chemical potential. Also, previous theoretical predictions suggested that the pseudo band gap of FeVAl switches from indirect to direct upon doping. In this work, we report first-principles calculations that correctly reproduce the experimentally measured thermoelectric properties of FeVAl. This is achieved by adding a larger Hubbard U term to V atoms than to Fe atoms and including a scissors operator afterwards. As a result, bulk FeVAl is modelled as a gapless semiconductor with maximum S values of 76 and -158 [Formula: see text]V K for p - and n-type, respectively, which agree well with the experimental measurements.
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http://dx.doi.org/10.1088/1361-648X/ab5867 | DOI Listing |
Phys Chem Chem Phys
January 2025
Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
An modelling workflow is used to predict the thermoelectric properties and figure of merit of the lanthanide cobalates LaCoO, PrCoO and NdCoO in the orthorhombic phase with the low-spin magnetic configuration. The LnCoO show significantly lower lattice thermal conductivity than the widely-studied SrTiO, due to lower phonon velocities, with a large component of the heat transport through an intraband tunnelling mechanism characteristic of amorphous materials. Comparison of the calculations to experimental measurements suggests the p-type electrical properties are significantly degraded by the thermal spin crossover, and materials-engineering strategies to suppress this could yield improved .
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
SKKU Advanced Institute of Nanotechnology (SAINT) and Department of Nano Science and Technology, Sungkyunkwan University, Suwon, 16419, Republic of Korea.
A novel additive method to boost the Seebeck coefficient of doped conjugated polymers without a significant loss in electrical conductivity is demonstrated. Perovskite (CsPbBr) quantum dots (QDs) passivated by ligands with long alkyl chains are mixed with a conjugated polymer in a solution phase to form polymer-QD blend films. Solution sequential doping of the blend film with AuCl solution not only doped the conjugated polymer but also decomposed the QDs, resulting in a doped conjugated polymer film embedded with separated ions dissociated from the QDs.
View Article and Find Full Text PDFSci Rep
January 2025
Astronomical Observatory, Jagiellonian University, Orla 171, Krakow, 30-244, Poland.
The single crystals of lead-free NaBiTiO were grown using the Czochralski method. The energy gaps determined from X-ray photoelectron spectroscopy (XPS) and optical measurements were approximately 2.92 eV.
View Article and Find Full Text PDFNat Commun
January 2025
Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA.
Despite rapid developments of wearable self-powered sensors, it is still elusive to decouple the simultaneously applied multiple input signals. Herein, we report the design and demonstration of stretchable thermoelectric porous graphene foam-based materials via facile laser scribing for self-powered decoupled strain and temperature sensing. The resulting sensor can accurately detect temperature with a resolution of 0.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Key Laboratory of Electromagnetic Processing of Materials (Ministry of Education), Northeastern University, Shenyang 110819, China.
A carbon nanotube (CNT) composite is an effective method to improve the thermoelectricity of materials. However, the depletion layer between the CNT and thermoelectric (TE) material always decreases the contribution of CNT to the conductivity of the TE material. It is important to eliminate the depletion layer for improving the TE properties.
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