Ultrathin few layer oxychalcogenide BiCuSeO nanosheets

2017 ◽  
Vol 4 (1) ◽  
pp. 84-90 ◽  
Author(s):  
Manisha Samanta ◽  
Satya N. Guin ◽  
Kanishka Biswas
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Chemical Synthesis ◽  
Large Scale ◽  
Lattice Thermal Conductivity ◽  
Soft Chemical Synthesis

Large scale ultrathin (∼3–4 nm thick and ∼1 μm long) few layered (4–5 layers) BiCuSeO nanosheets were synthesised by a facile soft chemical synthesis. BiCuSeO nanosheets exhibit lower lattice thermal conductivity and higher electrical conductivity than that of their bulk counterpart.

Investigation of Thermoelectric Materials: Substitution effect of Bi on the Ag1-xPb18MTe20 (M = Sb, Bi) (x = 0, 0.14, 0.3)

2007 ◽  
Vol 1044 ◽  
Author(s):  
Mi-kyung Han ◽  
Huijun Kong ◽  
Ctirad Uher ◽  
Mercouri G Kanatzidis
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Materials ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
Substitution Effect ◽  
Dimensionless Figure Of Merit ◽  
The Matrix ◽  
Mass Fluctuation

AbstractWe performed comparative investigations of the Ag1-xPb18MTe20 (M = Bi, Sb) (x = 0, 0.14, 0.3) system to better understand the roles of Sb and Bi on the thermoelectric properties. In both systems, the electrical conductivity nearly keeps the same values, while the Seebeck coefficient decreases dramatically in going from Sb to Bi. Compared to the lattice thermal conductivity of PbTe, that of AgPb18BiTe20 is substantially reduced. The lattice thermal conductivity of the Bi analog, however, is higher than that of AgPb18SbTe20 and this is attributed largely to the decrease in the degree of mass fluctuation between the nanostructures and the matrix (for the Bi analog). As a result the dimensionless figure of merit ZT of Ag1-xPb18MTe20 (M = Bi) is found to be smaller than that of Ag1-xPb18MTe20 (M = Sb).

Attaining reduced lattice thermal conductivity and enhanced electrical conductivity in as-sintered pure n-type Bi2Te3 alloy

2018 ◽  
Vol 54 (6) ◽  
pp. 4788-4797 ◽  
Author(s):  
Xiao-yu Wang ◽  
Hui-juan Wang ◽  
Bo Xiang ◽  
Hong-jing Shang ◽  
Bin Zhu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Lattice Thermal Conductivity

scholarly journals A Computational Survey of Semiconductors for Power Electronics

2019 ◽  
Author(s):  
Prashun Gorai ◽  
Robert McKinney ◽  
Nancy Haegel ◽  
Andriy Zakutayev ◽  
Vladan Stevanovic
Keyword(s):  
Thermal Conductivity ◽  
Power Electronics ◽  
Figure Of Merit ◽  
Large Scale ◽  
Lattice Thermal Conductivity ◽  
Consumer Products ◽  
Breakdown Field ◽  
Experimental Investigations ◽  
Wide Range ◽  
Screening Parameter

Power electronics (PE) are used to control and convert electrical energy in a wide range of applications from consumer products to large-scale industrial equipment. While Si-based power devices account for the vast majority of the market, wide band gap semiconductors such as SiC, GaN, and Ga2O3 are starting to gain ground. However, these emerging materials face challenges due to either non-negligible defect densities, or high synthesis and processing costs, or poor thermal properties. Here, we report on a broad computational survey aimed to identify promising materials for future power electronic devices beyond SiC, GaN, and Ga2O3. We consider 863 oxides, sulfides, nitrides, carbides, silicides, and borides that are reported in the crystallographic database and exhibit finite calculated band gaps. We utilize ab initio methods in conjunction with models for intrinsic carrier mobility, and critical breakdown field to compute the widely used Baliga figure of merit. We also compute the lattice thermal conductivity as a screening parameter. In addition to correctly identifying known PE materials, our survey has revealed a number of promising candidates exhibiting the desirable combination of high figure of merit and high lattice thermal conductivity, which we propose for further experimental investigations.

scholarly journals Silver vacancy concentration engineering leading to the ultralow lattice thermal conductivity and improved thermoelectric performance of Ag1-xInTe2

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Yaqiong Zhong ◽  
Yong Luo ◽  
Xie Li ◽  
Jiaolin Cui
Keyword(s):  
Crystal Structure ◽  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Point Defects ◽  
Lattice Thermal Conductivity ◽  
Vacancy Concentration ◽  
Antisite Defect ◽  
Thermoelectric Performance ◽  
Callaway Model

AbstractAgInTe2 compound has not received enough recognition in thermoelectrics, possibly due to the fact that the presence of Te vacancy (VTe) and antisite defect of In at Ag site (InAg) degrades its electrical conductivity. In this work, we prepared the Ag1-xInTe2 compounds with substoichiometric amounts of Ag and observed an ultralow lattice thermal conductivity (κL = 0.1 Wm−1K−1) for the sample at x = 0.15 and 814 K. This leads to more than 2-fold enhancement in the ZT value (ZT = 0.62) compared to the pristine AgInTe2. In addition, we have traced the origin of the untralow κL using the Callaway model. The results attained in this work suggest that the engineering of the silver vacancy (VAg) concentration is still an effective way to manipulate the thermoelectric performance of AgInTe2, realized by the increased point defects and modified crystal structure distortion as the VAg concentration increases.

High-temperature thermoelectric properties of n-type BayNixCo4−xSb12

2001 ◽  
Vol 16 (12) ◽  
pp. 3343-3346 ◽  
Author(s):  
X. F. Tang ◽  
L. M. Zhang ◽  
R. Z. Yuan ◽  
L. D. Chen ◽  
T. Goto ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
High Temperature ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Electron Concentration ◽  
Lattice Thermal Conductivity ◽  
Filling Fraction ◽  
Ni Content ◽  
Increasing Temperature

Effects of Ba filling fraction and Ni content on the thermoelectric properties of n-type BayNixCo4−xSb12 (x = 0−0.1, y = 0−0.4) were investigated at temperature range of 300 to 900 K. Thermal conductivity decreased with increasing Ba filling fraction and temperature. When y was fixed at 0.3, thermal conductivity decreased with increasing Ni content and reached a minimum value at about x = 0.05. Lattice thermal conductivity decreased with increasing Ni content, monotonously (y ≤ 0.1). Electron concentration and electrical conductivity increased with increasing Ba filling fraction and Ni content. Seebeck coefficient increased with increasing temperature and decreased with increasing Ba filling fraction and Ni content. The maximum ZT value of 1.25 was obtained at about 900 K for n-type Ba0.3Ni0.05Co3.95Sb12.

scholarly journals Electrical Transport and Thermoelectric Properties of SnSe–SnTe Solid Solution

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3854 ◽  
Author(s):  
Jun-Young Cho ◽  
Muhammad Siyar ◽  
Woo Chan Jin ◽  
Euyheon Hwang ◽  
Seung-Hwan Bae ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Solid Solution ◽  
Electrical Conductivity ◽  
Single Crystal ◽  
Carrier Concentration ◽  
Electrical Transport ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Practical Applications ◽  
Defect Sites

SnSe is considered as a promising thermoelectric (TE) material since the discovery of the record figure of merit (ZT) of 2.6 at 926 K in single crystal SnSe. It is, however, difficult to use single crystal SnSe for practical applications due to the poor mechanical properties and the difficulty and cost of fabricating a single crystal. It is highly desirable to improve the properties of polycrystalline SnSe whose TE properties are still not near to that of single crystal SnSe. In this study, in order to control the TE properties of polycrystalline SnSe, polycrystalline SnSe–SnTe solid solutions were fabricated, and the effect of the solid solution on the electrical transport and TE properties was investigated. The SnSe1−xTex samples were fabricated using mechanical alloying and spark plasma sintering. X-ray diffraction (XRD) analyses revealed that the solubility limit of Te in SnSe1−xTex is somewhere between x = 0.3 and 0.5. With increasing Te content, the electrical conductivity was increased due to the increase of carrier concentration, while the lattice thermal conductivity was suppressed by the increased amount of phonon scattering. The change of carrier concentration and electrical conductivity is explained using the measured band gap energy and the calculated band structure. The change of thermal conductivity is explained using the change of lattice thermal conductivity from the increased amount of phonon scattering at the point defect sites. A ZT of ~0.78 was obtained at 823 K from SnSe0.7Te0.3, which is an ~11% improvement compared to that of SnSe.

scholarly journals Efficient interlayer charge release for high-performance layered thermoelectrics

2020 ◽  
Author(s):  
Hao Zhu ◽  
Zhou Li ◽  
Chenxi Zhao ◽  
Xingxing Li ◽  
Jinlong Yang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Carrier Concentration ◽  
High Performance ◽  
Lattice Thermal Conductivity ◽  
Transport Barrier ◽  
High Seebeck Coefficient ◽  
Valence Bands ◽  
Increase Carrier Concentration

Abstract Many layered superlattice materials intrinsically possess large Seebeck coefficient and low lattice thermal conductivity, but poor electrical conductivity because of the interlayer transport barrier for charges, which has become a stumbling block for achieving high thermoelectric performance. Herein, taking BiCuSeO superlattice as an example, it is demonstrated that efficient interlayer charge release can increase carrier concentration, thereby activating multiple Fermi pockets through Bi/Cu dual vacancies and Pb codoping. Experimental results reveal that the extrinsic charges, which are introduced by Pb and initially trapped in the charge-reservoir [Bi2O2]2+ sublayers, are effectively released into [Cu2Se2]2− sublayers via the channels bridged by Bi/Cu dual vacancies. This efficient interlayer charge release endows dual-vacancy- and Pb-codoped BiCuSeO with increased carrier concentration and electrical conductivity. Moreover, with increasing carrier concentration, the Fermi level is pushed down, activating multiple converged valence bands, which helps to maintain a relatively high Seebeck coefficient and yield an enhanced power factor. As a result, a high ZT value of ∼1.4 is achieved at 823 K in codoped Bi0.90Pb0.06Cu0.96SeO, which is superior to that of pristine BiCuSeO and solely doped samples. The present findings provide prospective insights into the exploration of high-performance thermoelectric materials and the underlying transport physics.

Thermoelectric Properties of Solid-State Synthesized Magnesium Silicides Doped with Group BI-III Elements

2012 ◽  
Vol 724 ◽  
pp. 385-388 ◽  
Author(s):  
Sin Wook You ◽  
Soon Mok Choi ◽  
Won Seon Seo ◽  
Sun Uk Kim ◽  
Kyung Wook Jang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Solid State ◽  
Mechanical Alloying ◽  
Carrier Concentration ◽  
Thermoelectric Properties ◽  
Solid State Reaction ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
Group B

Group BI(Cu, Ag)-, BII(Zn)- and BIII(Al, In)-doped Mg2Si compounds were synthesized by solid state reaction and mechanical alloying. Electronic transport properties (Hall coefficient, carrier concentration and mobility) and thermoelectric properties (Seebeck coefficient, electrical conductivity, power factor, thermal conductivity and figure of merit) were examined. Mg2Si powder was synthesized successfully by solid state reaction at 773 K for 6 h and doped by mechanical alloying for 24 h. It was fully consolidated by hot pressing at 1073 K for 1 h. The electrical conductivity increased by doping due to an increase in the carrier concentration. However, the thermal conductivity did not changed significantly by doping, which was due to much larger contribution of the lattice thermal conductivity over the electronic thermal conductivity. Group BIII(Al, In) elements were more effective to enhance the thermoelectric properties of Mg2Si.

THERMOELECTRIC PROPERTIES OF p-TYPE SKUTTERUDITES (Pr0.25Nd0.75)xFe3CoSb12 BY LEVITATION MELTING AND SPARK PLASMA SINTERING

2013 ◽  
Vol 06 (05) ◽  
pp. 1340006 ◽  
Author(s):  
JINGSHU XU ◽  
CHENGUANG FU ◽  
JIAN XIE ◽  
XINBING ZHAO ◽  
TIEJUN ZHU
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Spark Plasma Sintering ◽  
Thermoelectric Properties ◽  
Lattice Thermal Conductivity ◽  
Levitation Melting ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
P Type

The p-type skutterudite compounds of ( Pr 0.25 Nd 0.75)x Fe 3 CoSb 12 (x = 0.67–0.78) have been successfully synthesized by levitation melting followed by annealing and spark plasma sintering. The thermoelectric properties have been characterized by the measurements of Seebeck coefficient, electrical conductivity and thermal conductivity in the temperature range from 300 K to 850 K. The improvement in the thermoelectric properties was realized due to the reduction in the lattice thermal conductivity when the voids were partially filled by Pr 0.25 Nd 0.75. The maximum ZT value of ~ 0.83 for ( Pr 0.25 Nd 0.75)0.76 Fe 3 CoSb 12 was obtained at 700 K.

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