Thermoelectric properties of CuCrSe[sub 2] (original) (raw)
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J. Mater. Chem. A, 2014
Recent studies have shown that thermoelectric materials exhibit a high figure-of-merit if it consists of hierarchically organized microstructures that significantly lower the lattice thermal conductivity without any appreciable change in the power factor. Here, we report a new class of thermoelectric (AgCrSe 2 ) 0.5 (CuCrSe 2 ) 0.5 nano-composites synthesized via the vacuum hot pressing of a mixture of the constituents, which naturally consists of phonon scattering centers in a multiscale hierarchical fashion,
Growth and Thermal Conductivity Study of CuCr2Se4-CuCrSe2 Hetero-Composite Crystals
Crystals, 2022
The CuCrSe2 shows attractive physical properties, such as thermoelectric and multiferroic properties, but pure-phase CuCrSe2 crystal is still quite challenging to obtain because CuCr2Se4 can be easily precipitated from a CuCrSe2 matrix. Here, taking the advantage of this precipitation reaction, we grew a series of CuCrSe2-CuCr2Se4 hetero-composites by adjusting growth parameters and explored their thermal conductivity property. Determined by electron-diffraction, the orientation relationship between these two compounds is [001] (100) CuCrSe2‖[111] (220) CuCr2Se4. The out-of-plane thermal conductivity κ of these hetero-composites was measured by a time-domain thermo-reflectance method. Fitting experimental κ by the Boltzmann-Callaway model, we verify that interface scattering plays significant role to κ in CuCrSe2-CuCr2Se4 hetero-composites, while in a CuCrSe2-dominated hetero-composite, both interface scattering and anharmonic three-phonon interaction lead to the lowest κ therein. O...
O ct 2 01 5 CuAlTe 2 : A promising bulk thermoelectric material
2018
Transport properties of Cu-based chalcopyrite materials a re presented using the full potential linear augmented plan e wave method and Boltzmann Semi-classical theory. All the st udied compounds appear to be direct band gap semiconductors evaluated based on the Tran-Blaha modified Becke-Jo hnson potential. The heavy and light band combination found near the valence band maximum (VBM) drive these materi als to possess good thermoelectric properties. Among the studied compounds, CuAlTe 2 is found to be more promising, in comparison with CuGaTe 2, which is reported to be an efficient thermoelectric material with appreciable figure of me rit. Another interesting fact about CuAlTe 2 is the comparable thermoelectric properties possessed by bot h n− type andp− type carriers, which might attract good device applications and are explained in detail using the el ectronic structure calculations.
Atomic-scale incorporation of CuAlSe 2 inclusions within the Cu 2 Se matrix, achieved through a solid-state transformation of CuSe 2 template precursor using elemental Cu and Al, enables a unique temperature-dependent dynamic doping of the Cu 2 Se matrix. The CuAlSe 2 inclusions, due to their ability to accommodate a large fraction of excess metal atoms within their crystal lattice, serve as a "reservoir" for Cu ions diffusing away from the Cu 2 Se matrix. Such unidirectional diffusion of Cu ions from the Cu 2 Se matrix to the CuAlSe 2 inclusion leads to the formation, near the CuAlSe 2 /Cu 2 Se interface, of a high density of Cu-deficient β-Cu 2−δ Se nanoparticles within the α-Cu 2 Se matrix and the formation of Cu-rich Cu 1+y AlSe 2 nanoparticles with the CuAlSe 2 inclusions. This gives rise to a large enhancement in carrier concentration and electrical conductivity at elevated temperatures. Furthermore, the nanostructuring near the CuAlSe 2 /Cu 2 Se interface, as well as the extensive atomic disorder in the Cu 2 Se and CuAlSe 2 phases, significantly increases phonon scattering, leading to suppressed lattice thermal conductivity. Consequently, a significant improvement in ZT is observed for selected Cu 2 Se/CuAlSe 2 composites. This work demonstrates the use of in situformed interactive secondary phases in a semiconducting matrix as an elegant alternative approach for further improvement of the performance of leading thermoelectric materials.
The Effect of Crystal Mismatch on the Thermoelectric Performance Enhancement of Nano Cu2Se
Frontiers in Materials, 2021
In the past decades, Cu2−xSe compounds have attracted great attention due to the inclusion of non-toxic and abundant elements, besides having a promising thermoelectric (TE) performance. In this work, we investigated the effect of a crystal mismatch of a nanoinclusion phase on the TE properties of Cu2−xSe. Nano-Cu2Se was synthesized using microwave assisted thermolysis, while the p-type skutterudite, Fe3.25Co0.75Sb12 (FeCoSb), compound was synthesized using a chemical alloying route. Nano-Cu2Se, and (nano-Cu2Se)1−x(nano-FeCoSb)x composites, where x = 0.05 and 0.1, were prepared via mechanical alloying followed by Spark Plasma Sintering process. Structural properties were evaluated by PXRD and SEM analysis, while the high temperature transport properties were examined via electrical conductivity, Seebeck coefficient, and thermal conductivity measurements in the temperature range of 300–800 K. Powder X-ray diffraction (PXRD) confirmed a single phase of nano Cu2Se, while the samples wi...
CuAlTe2: A promising bulk thermoelectric material
Journal of Alloys and Compounds, 2015
Transport properties of Cu-based chalcopyrite materials are presented using the full potential linear augmented plane wave method and Boltzmann Semi-classical theory. All the studied compounds appear to be direct band gap semiconductors evaluated based on the Tran-Blaha modified Becke-Johnson potential. The heavy and light band combination found near the valence band maximum (VBM) drive these materials to possess good thermoelectric properties. Among the studied compounds, CuAlTe 2 is found to be more promising, in comparison with CuGaTe 2 , which is reported to be an efficient thermoelectric material with appreciable figure of merit. Another interesting fact about CuAlTe 2 is the comparable thermoelectric properties possessed by both n− type and p− type carriers, which might attract good device applications and are explained in detail using the electronic structure calculations.
Thermoelectric properties of Ni-doped CuInTe2
Journal of Physics and Chemistry of Solids, 2015
Polycrystalline samples of composition Cu 1 À x Ni x InTe 2 (for x ¼0-0.05) were synthesized from elements of 5 N purity using a solid-state reaction. The phase purity of the products was verified by X-ray diffraction. Samples for measurement of the transport properties were prepared using hot-pressing. The samples were then characterized by the measurement of electrical conductivity, the Hall coefficient, the Seebeck coefficient, and the thermal conductivity over a temperature range of 300-675 K. All of the samples demonstrate p-type conductivity. We discuss the influence of Ni substitution on the free carrier concentration and the thermoelectric performance. The investigation of the thermoelectric properties shows an improvement up to 50% of ZT in the temperature range of 300-600 K.
High thermoelectric power factor in p-type Cu8GeSe6
DAE SOLID STATE PHYSICS SYMPOSIUM 2018, 2019
Having a unique crystal structure with large unit cell, the decoupling of charge and phonon transport in superionic compound Cu 8 GeSe 6 is possible for enhanced thermoelectric applications. Here, we report a promising Cu based superionic compound Cu 8 GeSe 6 which shows a high power factor and poor thermal conductivity. The metallic charge transport and poor thermal conductivity can be understood with high carrier concentration and disordered cations via weak Cu bonds respectively. The maximum power factor value reaches 264 μWm-1 K-2 at 638 K with thermoelectric figure of merit ZT ~ 0.3 at 623 K which is optimized for pure Cu 8 GeSe 6 .