scholarly journals Boosting the thermoelectric performance of p-type heavily Cu-doped polycrystalline SnSe via inducing intensive crystal imperfections and defect phonon scattering

2018 ◽  
Vol 9 (37) ◽  
pp. 7376-7389 ◽  
Author(s):  
Xiaolei Shi ◽  
Kun Zheng ◽  
Min Hong ◽  
Weidi Liu ◽  
Raza Moshwan ◽  
...  
Keyword(s):  
Single Crystal ◽  
Phonon Scattering ◽  
Thermoelectric Performance ◽  
Solvothermal Route ◽  
Crystal Imperfections ◽  
P Type ◽  
First Time

In this study, we, for the first time, report a high Cu solubility of 11.8% in single crystal SnSe microbelts synthesized via a facile solvothermal route.

The effect of device geometry and crystal orientation on the stress-dependent offset voltage of 3C–SiC(100) four terminal devices

2015 ◽  
Vol 3 (34) ◽  
pp. 8804-8809 ◽  
Author(s):  
Afzaal Qamar ◽  
Hoang-Phuong Phan ◽  
Jisheng Han ◽  
Philip Tanner ◽  
Toan Dinh ◽  
...  
Keyword(s):  
Single Crystal ◽  
Crystal Orientation ◽  
Offset Voltage ◽  
Device Geometry ◽  
Stress Dependent ◽  
P Type ◽  
The Impact ◽  
First Time

This communication reports for the first time, the impact of device geometry on the stress-dependent offset voltage of single crystal p-type 3C–SiC four terminal devices.

scholarly journals Higher thermoelectric performance of Zintl phases (Eu0.5Yb0.5)1−xCaxMg2Bi2 by band engineering and strain fluctuation

2016 ◽  
Vol 113 (29) ◽  
pp. E4125-E4132 ◽  
Author(s):  
Jing Shuai ◽  
Huiyuan Geng ◽  
Yucheng Lan ◽  
Zhuan Zhu ◽  
Chao Wang ◽  
...  
Keyword(s):  
Density Functional ◽  
Phonon Scattering ◽  
Theoretical Calculations ◽  
Thermoelectric Performance ◽  
Partial Substitution ◽  
Zintl Phases ◽  
Band Engineering ◽  
Transmission Electron ◽  
P Type ◽  
Callaway Model

Complex Zintl phases, especially antimony (Sb)-based YbZn0.4Cd1.6Sb2 with figure-of-merit (ZT) of ∼1.2 at 700 K, are good candidates as thermoelectric materials because of their intrinsic “electron–crystal, phonon–glass” nature. Here, we report the rarely studied p-type bismuth (Bi)-based Zintl phases (Ca,Yb,Eu)Mg2Bi2 with a record thermoelectric performance. Phase-pure EuMg2Bi2 is successfully prepared with suppressed bipolar effect to reach ZT ∼ 1. Further partial substitution of Eu by Ca and Yb enhanced ZT to ∼1.3 for Eu0.2Yb0.2Ca0.6Mg2Bi2 at 873 K. Density-functional theory (DFT) simulation indicates the alloying has no effect on the valence band, but does affect the conduction band. Such band engineering results in good p-type thermoelectric properties with high carrier mobility. Using transmission electron microscopy, various types of strains are observed and are believed to be due to atomic mass and size fluctuations. Point defects, strain, dislocations, and nanostructures jointly contribute to phonon scattering, confirmed by the semiclassical theoretical calculations based on a modified Debye–Callaway model of lattice thermal conductivity. This work indicates Bi-based (Ca,Yb,Eu)Mg2Bi2 is better than the Sb-based Zintl phases.

Condensed [PtIn3/3] and [PtIn6/6] Units as Structural Motifs in ScPtln, TbPtln, and HoPtln

2000 ◽  
Vol 55 (11) ◽  
pp. 1025-1030 ◽  
Author(s):  
Yaroslav V. Galadzhun ◽  
Vasyl' I. Zaremba ◽  
Holger Piotrowski ◽  
Peter Mayer ◽  
Rolf-Dieter Hoffmann ◽  
...  
Keyword(s):  
Single Crystal ◽  
Three Dimensional ◽  
Melting Furnace ◽  
Structural Motifs ◽  
Variable Parameters ◽  
Space Group ◽  
X Ray ◽  
Arc Melting ◽  
P Type ◽  
First Time

The ternary indides ScPtln, TbPtln, and HoPtln were synthesized by reaction of the elements in an arc-melting furnace and subsequent annealing for four weeks. ScPtln and HoPtln are reported here for the first time. The three indides crystallize with the hexagonal ZrNiAl structure, a ternary ordered version of the Fe2P type, space group P6̄2m. Single crystal X-ray data yielded a = 754.6(1), c = 348.31(8) pm, wR2 = 0.0390, 177 F2 values for ScPtln, a = 759.3(1), c = 387.6(1) pm, wR2 = 0.0576, 183 F2 values for TbPtln, and a = 758.13(1), c = 381.62(1) pm, wR2 = 0.0530, 239 F2 values for HoPtln with 14 variable parameters for each refinement. Striking structural motifs of these intermetallics are short Pt-In distances (270 - 286 pm) within the three-dimensional [Ptln] polyanions which are composed of Pt(2)In6 trigonal prisms and trigonal planar P t(l)In3 units. The platinum-indium substructure of ScPtln is discussed in comparison with the various platinum-indium networks in the structures of Ptln2, Pt3In7, SrPtln, Sr2Pt3ln4, SrPtIn2, LaPtIn3, and PtIn7Fi3.

scholarly journals Phonon Scattering and Suppression of Bipolar Effect in MgO/VO2 Nanoparticle Dispersed p-Type Bi0.5Sb1.5Te3 Composites

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2506
Author(s):  
Song Yi Back ◽  
Jae Hyun Yun ◽  
Hyunyong Cho ◽  
Gareoung Kim ◽  
Jong-Soo Rhyee
Keyword(s):  
Thermal Conductivity ◽  
Phonon Scattering ◽  
Oxide Particle ◽  
Critical Issue ◽  
Thermoelectric Performance ◽  
Phase Mixing ◽  
Bulk Matrix ◽  
Filtering Effect ◽  
P Type ◽  
Thermal Conductivities

Bismuth-Telluride-based compounds are unique materials for thermoelectric cooling applications. Because Bi2Te3 is a narrow gap semiconductor, the bipolar diffusion effect is a critical issue to enhance thermoelectric performance. Here, we report the significant reduction of thermal conductivity by decreasing lattice and bipolar thermal conductivity in extrinsic phase mixing of MgO and VO2 nanoparticles in Bi0.5Sb1.5Te3 (BST) bulk matrix. When we separate the thermal conductivity by electronic κel, lattice κlat, and bipolar κbi thermal conductivities, all the contributions in thermal conductivities are decreased with increasing the concentration of oxide particle distribution, indicating the effective phonon scattering with an asymmetric scattering of carriers. The reduction of thermal conductivity affects the improvement of the ZT values. Even though significant carrier filtering effect is not observed in the oxide bulk composites due to micro-meter size agglomeration of particles, the interface between oxide and bulk matrix scatters carriers giving rise to the increase of the Seebeck coefficient and electrical resistivity. Therefore, we suggest the extrinsic phase mixing of nanoparticles decreases lattice and bipolar thermal conductivity, resulting in the enhancement of thermoelectric performance over a wide temperature range.

Impact of Nb vacancies and p-type doping of the NbCoSn–NbCoSb half-Heusler thermoelectrics

2018 ◽  
Vol 20 (6) ◽  
pp. 3979-3987 ◽  
Author(s):  
Daniella A. Ferluccio ◽  
Ronald I. Smith ◽  
Jim Buckman ◽  
Jan-Willem G. Bos
Keyword(s):  
Phonon Scattering ◽  
Thermoelectric Performance ◽  
P Type ◽  
Mass Fluctuation

Nb vacancies maintain a semiconducting electron count and cause strong mass fluctuation phonon scattering enabling good thermoelectric performance.

scholarly journals Localized double phonon scattering and DOS induced thermoelectric enhancement of degenerate nonstoichiometric Li1−xNbO2 compounds

RSC Advances ◽  
2017 ◽  
Vol 7 (84) ◽  
pp. 53255-53264 ◽  
Author(s):  
Jamil Ur Rahman ◽  
Nguyen Van Du ◽  
Gul Rahman ◽  
V. M. García-Suárez ◽  
Won-Seon Seo ◽  
...  
Keyword(s):  
Thermoelectric Properties ◽  
Thermoelectric Material ◽  
Significant Role ◽  
Phonon Scattering ◽  
Thermoelectric Performance ◽  
Oxide Thermoelectric Material ◽  
P Type

We report the synthesis and thermoelectric properties of a new p-type oxide thermoelectric material (Li1−xNbO2, with x = 0–0.6), in which Li-vacancies play a significant role in the enhancement of the thermoelectric performance.

Influence of Metal Substitution on the Pressure-Induced Phase Change in Flexible Zeolitic Imidazolate Frameworks

2018 ◽  
Author(s):  
C. Michael McGuirk ◽  
Tomče Runčevski ◽  
Julia Oktawiec ◽  
Ari Turkiewicz ◽  
mercedes K. taylor ◽  
...  
Keyword(s):  
Phase Change ◽  
Single Crystal ◽  
Gas Adsorption ◽  
High Capacity ◽  
Phase Changes ◽  
Zeolitic Imidazolate Frameworks ◽  
Metal Substitution ◽  
Heat Management ◽  
Metal Organic ◽  
First Time

<p>Metal–organic frameworks that display step-shaped adsorption profiles arising from discrete pressure-induced phase changes are promising materials for applications in both high-capacity gas storage and energy-efficient gas separations. The thorough investigation of such materials through chemical diversification, gas adsorption measurements, and <i>in situ </i>structural characterization is therefore crucial for broadening their utility. We examine a series of isoreticular, flexible zeolitic imidazolate frameworks (ZIFs) of the type M(bim)<sub>2</sub> (SOD; M = Zn<sup> </sup>(ZIF-7), Co (ZIF-9), Cd (CdIF-13); bim<sup>–</sup> = benzimidazolate), and elucidate the effects of metal substitution on the pressure-responsive phase changes and the resulting CO<sub>2</sub> and CH<sub>4</sub> step positions, pre-step uptakes, and step capacities. Using ZIF-7 as a benchmark, we reexamine the poorly understood structural transition responsible for its adsorption steps and, through high-pressure adsorption measurements, verify that it displays a step in its CH<sub>4 </sub>adsorption isotherms. The ZIF-9 material is shown to undergo an analogous phase change, yielding adsorption steps for CO<sub>2</sub> and CH<sub>4</sub> with similar profiles and capacities to ZIF-7, but with shifted threshold pressures. Further, the Cd<sup>2+</sup> analogue CdIF-13 is reported here for the first time, and shown to display adsorption behavior distinct from both ZIF-7 and ZIF-9, with negligible pre-step adsorption, a ~50% increase in CO<sub>2</sub> and CH<sub>4</sub> capacity, and dramatically higher threshold adsorption pressures. Remarkably, a single-crystal-to-single-crystal phase change to a pore-gated phase is also achieved with CdIF-13, providing insight into the phase change that yields step-shaped adsorption in these flexible ZIFs. Finally, we show that the endothermic phase change of these frameworks provides intrinsic heat management during gas adsorption. </p>

High Thermoelectric Performance of ZnO by Coherent Phonon Scattering and Optimized Charge Transport

2021 ◽  
pp. 2105008
Author(s):  
Somnath Acharya ◽  
Byung‐Kyu Yu ◽  
Junphil Hwang ◽  
Jiyong Kim ◽  
Woochul Kim
Keyword(s):  
Charge Transport ◽  
Phonon Scattering ◽  
Thermoelectric Performance ◽  
Coherent Phonon
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