In this study, we introduce our numerical and experimental works for the thermal conductivity reduction by using a porous material. Recently thermal conductivity reduction has been one of the key technologies to enhance the figure of merit (ZT) of a thermoelectric material. We carry out numerical calculations of heat conduction in porous materials, such as phonon Boltzmann transport (BTE) and molecular dynamics (MD) simulations, in order to investigate the mechanism of the thermal conductivity reduction of a porous material. In the BTE, we applied the periodic boundary conditions with constant heat flux to calculate the effective thermal conductivity of porous materials.In the MD simulation, we calculated the phonon properties of Si by using the Stillinger–Weber potential at constant temperature with periodic boundary conditions in the x, y, and z directions. Phonon dispersion curves of single crystal of Si calculated from MD results by time-space 2D FFT are agreed well with reference data. Moreover, the effects of nanoporous structures on both the phonon group velocity and the phonon density of states (DOS) are discussed. At last, we made a porous p-type Bi2Te3 by nanoparticles prepared by a beads milling method. The thermal conductivity is one-fifth of that of a bulk material as well as keeping the same Seebeck coefficient as the bulk value. However, electrical conductivity was much reduced, and the ZT was only 0.048.

References

1.
Cahill
,
D. G.
,
Ford
,
W. K.
,
Goodson
,
K. E.
,
Mahan
,
G. D.
,
Majumdar
,
A.
,
Maris
,
H. J.
,
Merlin
,
R.
, and
Phillpot
,
S. R.
, 2003, “
Nanoscale Thermal Transport
,”
J. Appl. Phys.
,
93
(
2
), pp.
793
818
.
2.
Chen
,
G.
, and
Shakouli
,
A.
, 2002, “
Heat Transfer in Nanostructures for Solid-State Energy Conversion
,”
ASME J. Heat Transfer
,
124
(
2
), pp.
242
252
.
3.
Venkatasubramanian
,
R.
,
Siivola
,
E.
,
Colpitts
,
T.
, and
O’Quinn
,
B.
, 2001, “
Thin-Film Thermoelectric Devices With High Room-Temperature Figures of Merit
,”
Nature
,
413
, pp.
597
602
.
4.
Harman
,
T. C.
,
Taylor
,
P. J.
,
Walsh
,
M. P.
, and
LaForge
B. E.
, 2002, “
Quantum Dot Superlattice Thermoelectric Materials and Devices
,”
Science
,
297
, pp.
2229
2232
.
5.
Hsu
,
K. F.
,
Loo
,
S.
,
Guo
,
F.
,
Chen
,
W.
,
Dyck
,
J. S.
,
Uher
,
C.
,
Hogan
,
T.
,
Polychroniadis
,
E. K.
, and
Kanatzidis
,
M. G.
, 2004, “
Cubic AgPbmSbTe2+m: Bulk Thermoelectric Materials With High Figure of Merit
,”
Science
,
303
, pp.
818
821
.
6.
Chiritescu
,
C.
,
Cahill
,
D. G.
,
Nguyen
,
N.
,
Johnson
,
D.
,
Bodapati
,
A.
,
Keblinski
,
P.
, and
Zschack
,
P.
, 2007, “
Ultralow Thermal Conductivity in Disordered, Layered WSe2 Crystals
,”
Science
,
315
, pp.
351
353
.
7.
Hochbaum
,
A. I.
,
Chen
,
R.
,
Delgado
,
R. D.
,
Liang
,
W.
,
Garnett
,
E. C.
,
Najarian
,
M.
,
Majumdar
,
A.
, and
Yang
,
P.
, 2008, “
Enhanced Thermoelectric Performance of Rough Silicon Nanowires
,”
Nature
,
451
, pp.
163
168
.
8.
Poudel
,
B.
,
Hao
,
Q.
,
Ma
,
Y.
,
Lan
,
Y.
Minnich
,
A.
,
Yu
,
B.
,
Yan
,
X.
,
Wang
,
D.
,
Muto
,
A.
,
Vashaee
,
D.
,
Chen
,
X.
,
Liu
,
J.
,
Dressselhaus
,
M. S.
,
Chen
,
G.
, and
Ren
,
Z.
, 2008, “
High-Thermoelectric Performance of Nanostructured Bismuth Antimony Telluride Bulk Alloys
,”
Science
,
320
, pp.
634
638
.
9.
Yang
,
B.
, and
Chen
,
G.
, 2003, “
Partially Coherent Phonon Heat Conduction in Superlattices
,”
Phys. Rev. B
,
67
(
19
), p.
195311
.
10.
Yang
,
R.
, and
Chen
,
G.
, 2004, “
Thermal Conductivity Modeling of Periodic Two-Dimensional Nanocomposites
,”
Phys. Rev. B
,
69
(
19
), p.
195316
.
11.
Dames
,
C.
, and
Chen
,
G.
, 2004, “
Theoretical Phonon Thermal Conductivity of Si/Ge Superlattice Nanowires
,”
J. Appl. Phys.
,
95
(
2
), pp.
682
693
.
12.
Miyazaki
,
K.
,
Arashi
,
T.
,
Makino
,
D.
, and
Tsukamoto
,
H.
, 2006, “
Heat Conduction in Microstructured Materials
,”
IEEE Compon., Packag., Manuf. Technol.
,
29
(
2
), pp.
247
253
.
13.
Tamura
,
S.
,
Tanaka
,
Y.
, and
Maris
,
H. J.
, 1999, “
Phonon Group Velocity and Thermal Conduction in Superlattices
,”
Phys. Rev. B
,
60
(
4
), pp.
2627
2630
.
14.
Yang
,
B.
, and
Chen
,
G.
, 2001, “
Lattice Dynamics Study of Anisotropic Heat Conduction in Superlattices
,”
Microscale Thermophys. Eng.
,
5
, pp.
107
116
.
15.
Volz
,
S. G.
, and
Chen
,
G.
, 1997, “
Molecular Dynamics Simulation of Thermal Conductivity of Silicon Nanowires
,”
ASME J. Heat Transfer
,
119
(
2
), pp.
220
229
.
16.
Volz
,
S. G.
, and
Chen
,
G.
, 2000, “
Molecular-Dynamics Simulation of Thermal Conductivity of Silicon Crystals
,”
Phys. Rev. B
,
61
(
4
), pp.
2651
2656
.
17.
Henry
,
A.
, and
Chen
,
G.
, 2008, “
Spectral Phonon Transport Properties of Silicon Based on Molecular Dynamics Simulations and Lattice Dynamics
,”
J. Comput. Theor. Nanosci.
,
5
, pp.
141
152
.
18.
Bowen
,
P.
,
Carry
,
C.
,
Luxembourg
,
D.
, and
Hofmannet
,
H.
, 2005, “
Colloidal Processing and Sintering of Nanosized Transition Aluminas
,”
Powder Technol.
,
157
, pp.
100
107
.
19.
Inkyo
,
M.
,
Tahara
,
T.
,
Iwaki
,
T.
,
Iskandar
,
F.
,
Hogan
Jr.,
C. J.
, and
Okuyama
,
K.
, 2006, “
Experimental Investigation of Nanoparticle Dispersion by Beads Milling With Centrifugal Bead Separation
,”
J. Colloid Interf. Sci.
,
304
, pp.
535
540
.
20.
Kittel
,
C.
, 1986,
Introduction to Solid State Physics
, 6th ed.,
John Wiley & Sons, Inc.
,
New York
.
21.
Ashcroft
,
N. W.
, and
Marmin
,
N. D.
, 1976,
Solid State Physics
,
Saunders College Publishing
,
Fort Worth, TX
.
22.
Chen
,
G.
, 2005,
Nanoscale Energy Transport and Conversion: A Parallel Treatment of Elections, Molecules, Phonons, and Photons
,
Oxford University Press
,
London
.
23.
Majumdar
,
A.
, 1993, “
Microscale Heat Conduction in Dielectric Thin Films
,”
ASME J. Heat Transfer
,
115
(
1
), pp.
7
16
.
24.
Joshi
,
A. A.
, and
Majumdar
,
A.
, 1993, “
Transient Ballistic and Diffusive Phonon Heat Transport in Thin Films
,”
J. Appl. Phys.
,
74
, pp.
31
39
.
25.
Mazumder
,
S.
, and
Majumdar
,
A.
, 2001, “
Monte Carlo Study of Phonon Transport in Solid Thin Films Including Dispersion and Polarization
,”
ASME J. Heat Transfer
,
123
(
4
), pp.
749
759
.
26.
Narumanchi
,
S. V. J.
,
Murthy
,
Y. J.
, and
Amon
,
C. H.
, 2004, “
Submicron Heat Transport Model in Silicon Accounting for Phonon Dispersion and Polarization
,”
ASME J. Heat Transfer
,
126
(
6
), pp.
946
955
.
27.
Ju
,
Y. S.
, and
Goodson
,
K. E.
, 2004, “
Phonon Scattering in Silicon Films With Thickness of Order 100 nm
,”
Appl. Phys. Lett.
,
74
(
20
), pp.
3005
3007
.
28.
Ziman
,
J. M.
, 1985,
Electrons and Phonons
,
Oxford University Press
,
London
.
29.
Haile
,
J. M.
, 1992,
Molecular Dynamics Simulation
,
John Wiley & Sons, Inc.
,
New York
.
30.
Stillinger
,
F. H.
, and
Weber
,
T. A.
, 1985, “
Computer Simulation of Local Order in Condensed Phases of Silicon
,
Phys. Rev. B
,
31
(
8
), pp.
5262
5268
.
31.
Schelling
,
P. K.
,
Phillpot
,
S. R.
, and
Keblinski
,
P.
, 2002, “
Comparison of Atomic-Level Simulation Methods for Computing Thermal Conductivity
,”
Phys. Rev. B
,
65
(
14
), p.
144306
.
32.
Swope
,
W. C.
,
Andersen
,
H. C.
,
Berens
,
P. H.
, and
Wilson
,
K. R.
, 1982, “
A Computer Simulation Method for the Calculation of Equilibrium Constants for the Formation of Physical Clusters of Molecules: Application to Small Water Clusters
,”
J. Chem. Phys.
,
76
, pp.
637
649
.
33.
Maruyama
,
S.
, 2002, “
A Molecular Dynamics Simulation of Heat Conduction in Finite Length of SWNTs
,”
Physica B
,
323
, pp.
193
195
.
34.
Ibach
,
H.
, and
Lüth
,
H.
, 1981,
Solid-State Physics
,
Springer-Verlag
,
Berlin
.
35.
Dickey
,
J. M.
, and
Paskin
,
A.
, 1969, “
Computer Simulation of the Lattice Dynamics of Solids
,”
Phys. Rev.
,
188
(
3
), pp.
1407
1418
.
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