Structural and thermoelectric properties of the type-I Sn clathrates Cs8Sn46−n(n=0,2) from Density Functional Theory (DFT)

MRS Advances ◽  
2018 ◽  
Vol 3 (37) ◽  
pp. 2143-2149
Author(s):  
Peter O. Egbele ◽  
Elvis Shoko ◽  
Daniel P. Joubert
Keyword(s):  
Thermal Conductivity ◽  
Figure Of Merit ◽  
Density Functional ◽  
Type I ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Clathrate Compound ◽  
Electron Crystal

Abstract:Sn clathrates are promising phonon glass, electron crystal materials (PGEC), in which the phonon free paths are short and the electron free paths are long. We analysed the relaxed structure of Sn clathrates using four different Density Funtional Exchange-Correlation functionals. The phonon structures were investigated as a first step in order to determine the phonon contribution to the thermal conductivity. We determined the Seebeck coefficient and electrical conductivity of the clathrate compound and the thermoelectric figure of merit. A glimpse into the dynamics of the system for the evaluation of the thermoelectric and electronic properties is presented.

scholarly journals Ultralow lattice thermal conductivity of chalcogenide perovskite CaZrSe3 contributes to high thermoelectric figure of merit

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Eric Osei-Agyemang ◽  
Challen Enninful Adu ◽  
Ganesh Balasubramanian
Keyword(s):  
Thermal Conductivity ◽  
Figure Of Merit ◽  
Density Functional ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Mean Free Path ◽  
Thermoelectric Figure Of Merit ◽  
Boltzmann Transport ◽  
Phonon Modes ◽  
Thermoelectric Figure

AbstractAn emerging chalcogenide perovskite, CaZrSe3, holds promise for energy conversion applications given its notable optical and electrical properties. However, knowledge of its thermal properties is extremely important, e.g. for potential thermoelectric applications, and has not been previously reported in detail. In this work, we examine and explain the lattice thermal transport mechanisms in CaZrSe3 using density functional theory and Boltzmann transport calculations. We find the mean relaxation time to be extremely short corroborating an enhanced phonon–phonon scattering that annihilates phonon modes, and lowers thermal conductivity. In addition, strong anharmonicity in the perovskite crystal represented by the Grüneisen parameter predictions, and low phonon number density for the acoustic modes, results in the lattice thermal conductivity to be limited to 1.17 W m−1 K−1. The average phonon mean free path in the bulk CaZrSe3 sample (N → ∞) is 138.1 nm and nanostructuring CaZrSe3 sample to ~10 nm diminishes the thermal conductivity to 0.23 W m−1 K−1. We also find that p-type doping yields higher predictions of thermoelectric figure of merit than n-type doping, and values of ZT ~0.95–1 are found for hole concentrations in the range 1016–1017 cm−3 and temperature between 600 and 700 K.

Influence of multi-sintering on the thermoelectric properties of Bi2Sr2Co2Oy ceramics

2019 ◽  
Vol 34 (02) ◽  
pp. 2050019 ◽  
Author(s):  
Y. Zhang ◽  
M. M. Fan ◽  
C. C. Ruan ◽  
Y. W. Zhang ◽  
X.-J. Li ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Phonon Scattering ◽  
Sintered Sample ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
The Third ◽  
Ceramic Samples ◽  
Optimum Formula

[Formula: see text] ceramic samples have a structure similar to phonon glass electronic crystals, and their thermoelectric properties can be effectively adjusted through repeated grinding and sintering. The results show that multi-sintering can make their grain refined and increase their grain boundary, which will effectively increase density and phonon scattering. Finally, multi-sintering can reduce the resistivity and thermal conductivity, thus obviously improve thermoelectric figure of merit [Formula: see text] of [Formula: see text]. The optimum [Formula: see text] value of 0.26 is achieved at 923 K by the third sintered sample.

Effects of Ce filling fraction and Fe content on the thermoelectric properties of Co-rich CeyFexCo4−xSb12

2001 ◽  
Vol 16 (3) ◽  
pp. 837-843 ◽  
Author(s):  
Xinfeng Tang ◽  
Lidong Chen ◽  
Takashi Goto ◽  
Toshio Hirai
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Single Phase ◽  
Lattice Thermal Conductivity ◽  
Hole Concentration ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Filling Fraction ◽  
Fe Content

Single-phase filled skutterudite compounds, CeyFexCo4−xSb12 (x = 0 to 3.0, y = 0 to 0.74), were synthesized by a melting method. The effects of Fe content and Ce filling fraction on the thermoelectric properties of CeyFexCo4−xSb12 were investigated. The lattice thermal conductivity of Ce-saturated CeyFexCo4−xSb12, y being at the maximum corresponding to x, decreased with increasing Fe content (x) and reached its minimum at about x = 1.5. When x was 1.5, lattice thermal conductivity decreased with increasing Ce filling fraction till y = 0.3 and then began to increase after reaching the minimum at y = 0.3. Hole concentration and electrical conductivity of Cey Fe1.5Co2.5Sb12 decreased with increasing Ce filling fraction. The Seebeck coefficient increased with increasing Ce filling fraction. The greatest dimensionless thermoelectric figure of merit T value of 1.1 was obtained at 750 K for the composition of Ce0.28Fe1.52Co2.48Sb12.

Thermoelectric Properties of Semiconducting Intermetallic Compounds: FeGa3and RuGa3

2003 ◽  
Vol 793 ◽  
Author(s):  
Y. Amagai ◽  
A. Yamamoto ◽  
C. H. Lee ◽  
H. Takazawa ◽  
T. Noguchi ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
High Temperature ◽  
Seebeck Coefficient ◽  
Transport Properties ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
High Seebeck Coefficient

ABSTRACTWe report transport properties of polycrystalline TMGa3(TM = Fe and Ru) compounds in the temperature range 313K<T<973K. These compounds exhibit semiconductorlike behavior with relatively high Seebeck coefficient, electrical resistivity, and Hall carrier concentrations at room temperature in the range of 1017- 1018cm−3. Seebeck coefficient measurements reveal that FeGa3isn-type material, while the Seebeck coefficient of RuGa3changes signs rapidly from large positive values to large negative values around 450K. The thermal conductivity of these compounds is estimated to be 3.5Wm−1K−1at room temperature and decreased to 2.5Wm−1K−1for FeGa3and 2.0Wm−1K−1for RuGa3at high temperature. The resulting thermoelectric figure of merit,ZT, at 945K for RuGa3reaches 0.18.

scholarly journals Термоэлектрические свойства нанокомпозитного Bi-=SUB=-0.45-=/SUB=-Sb-=SUB=-1.55-=/SUB=-Te-=SUB=-2.985-=/SUB=- с микрочастицами SiO-=SUB=-2-=/SUB=-

2019 ◽  
Vol 53 (6) ◽  
pp. 751
Author(s):  
А.А. Шабалдин ◽  
П.П. Константинов ◽  
Д.А. Курдюков ◽  
Л.Н. Лукьянова ◽  
А.Ю. Самунин ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Solid Solution ◽  
Electrical Conductivity ◽  
Wide Temperature Range ◽  
Figure Of Merit ◽  
Nanostructured Material ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Efficiency ◽  
Thermoelectric Figure ◽  
P Type

AbstractNanocomposite thermoelectrics based on Bi_0.45Sb_1.55Te_2.985 solid solution of p -type conductivity are fabricated by the hot pressing of nanopowders of this solid solution with the addition of SiO_2 microparticles. Investigations of the thermoelectric properties show that the thermoelectric power of the nanocomposites increases in a wide temperature range of 80–420 K, while the thermal conductivity considerably decreases at 80–320 K, which, despite a decrease in the electrical conductivity, leads to an increase in the thermoelectric efficiency in the nanostructured material without the SiO_2 addition by almost 50% (at 300 K). When adding SiO_2, the efficiency decreases. The initial thermoelectric fabricated without nanostructuring, in which the maximal thermoelectric figure of merit ZT = 1 at 390 K, is most efficient at temperatures above 350 K.

scholarly journals Термоэлектрические свойства твердых растворов (CuInSe-=SUB=-2-=/SUB=-)-=SUB=-1-x-=/SUB=-(In-=SUB=-2-=/SUB=-Te-=SUB=-3-=/SUB=-)-=SUB=-x-=/SUB=-

2022 ◽  
Vol 56 (1) ◽  
pp. 38
Author(s):  
Ч.И. Абилов ◽  
М.Ш. Гасанова ◽  
Н.Т. Гусейнова ◽  
Э.К. Касумова
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Solid Solutions ◽  
Figure Of Merit ◽  
Charge Carriers ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Mobility Of Charge Carriers ◽  
Temperature Dependences ◽  
Thermoelectric Coefficient

The results of studying the temperature dependences of electrical conductivity, thermoelectric coefficient, Hall mobility of charge carriers, total and electronic thermal conductivity, as well as phonon thermal resistance of alloys of (CuInSe2)1-x(In2Te3)x solid solutions at x=0.005 and 0.0075 are presented. The values ​​of these parameters for certain temperatures were used to calculate the values ​​of the thermoelectric figure of merit of the indicated compositions. It turned out that as the temperature rises, the thermoelectric figure of merit tends to grow strongly, from which it can be concluded that these materials can be used in the manufacture of thermoelements.

Thermoelectric Transport Properties of SrTiO3 Doped with Pm

2018 ◽  
Vol 280 ◽  
pp. 3-8 ◽  
Author(s):  
A. A. Adewale ◽  
Abdullah Chik ◽  
R. Mohd Zaki ◽  
F. Che Pa ◽  
Yeoh Chow Keat ◽  
...  
Keyword(s):  
Transport Properties ◽  
Figure Of Merit ◽  
Density Functional ◽  
Generalized Gradient ◽  
Thermoelectric Figure ◽  
Functional Theory ◽  
Thermoelectric Transport ◽  
Generalized Gradient Approximation ◽  
High Contribution ◽  
Thermoelectric Transport Properties

Thermoelectric properties of SrTiO3doped with 8%Pm at Sr site were investigated using density functional theory and generalized gradient approximation. The transport properties were calculated based on BoltzTraP code at temperature range 300-1200K. In electronic properties study Fermi level were shifted to conduction band region due to high contribution 4f orbital in Pm. Present study thermoelectric figure of merit ZT result was 0.395 at 300K and 0.638 at 1200K. This shows a considerably good value of ZT for SrTiO3as n-type oxide. Compared to previous work, ZT were at the range of 0.21 - 0.37 for temperature of 300-1000K in Pr, La, Ta and Ho.

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