Electron and Phonon Transport in n- and p-type Skutterudites

2013 ◽  
Vol 1490 ◽  
pp. 9-18 ◽  
Author(s):  
Jiong Yang ◽  
S. Wang ◽  
Jihui Yang ◽  
W. Zhang ◽  
L. Chen
Keyword(s):  
Power Factor ◽  
Thermal Conduction ◽  
Elevated Temperatures ◽  
Phonon Transport ◽  
Strong Electron ◽  
Electronic Band ◽  
Filled Skutterudites ◽  
Module Development ◽  
P Type ◽  
Electronic Band Structures

ABSTRACTFilled skutterudites are one of the most promising materials for thermoelectric (TE) power generation applications at intermediate temperatures due to their superior TE and thermomechanical performance as compared to other materials. In the past, we have demonstrated that n-type skutterudites can be optimized so that their maximum TE figure of merit reaches 1.7 at 850 K. TE performance of the p-type, however, is lagging behind, which hinders the optimization of skutterudites-based TE module development. In this paper we reveal that the underlying reasons for inferior TE properties of the p-type root in their electronic band structures, which result in higher thermal conductivity at elevated temperatures due to bipolar lattice thermal conduction and lower power factor because of heavy valance bands induced strong electron-phonon interactions. We also identify means of improving the power factor and reducing bipolar effect.

A High Thermoelectric Performance ZT in p-Type LaSe2 Crystal

2021 ◽  
Vol 871 ◽  
pp. 203-207
Author(s):  
Jian Liu
Keyword(s):  
Thermal Conductivity ◽  
Power Factor ◽  
High Power ◽  
Density Functional ◽  
Lattice Thermal Conductivity ◽  
Phonon Transport ◽  
Thermoelectric Performance ◽  
Boltzmann Transport ◽  
High Power Factor ◽  
P Type

In this work, we use first principles DFT calculations, anharmonic phonon scatter theory and Boltzmann transport method, to predict a comprehensive study on the thermoelectric properties as electronic and phonon transport of layered LaSe2 crystal. The flat-and-dispersive type band structure of LaSe2 crystal offers a high power factor. In the other hand, low lattice thermal conductivity is revealed in LaSe2 semiconductor, combined with its high power factor, the LaSe2 crystal is considered a promising thermoelectric material. It is demonstrated that p-type LaSe2 could be optimized to exhibit outstanding thermoelectric performance with a maximum ZT value of 1.41 at 1100K. Explored by density functional theory calculations, the high ZT value is due to its high Seebeck coefficient S, high electrical conductivity, and low lattice thermal conductivity .

scholarly journals Finding the Order in Complexity: The Electronic Structure of 14-1-11 Zintl Compounds

2021 ◽  
Author(s):  
Yukun Liu ◽  
Michael Toriyama ◽  
Zizhen Cai ◽  
Mengjia Zhao ◽  
Fei Liu ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Molecular Orbital ◽  
Electronic Band Structure ◽  
Orbital Theory ◽  
Electronic Band ◽  
High Performing ◽  
Band Engineering ◽  
Complex Crystal Structure ◽  
P Type ◽  
Electronic Band Structures

Yb14MnSb11 and Yb14MgSb11 have rapidly risen to prominence as high-performing p-type thermoelectric materials for potential deep space power generation. However, the fairly complex crystal structure of 14-1-11 Zintl compounds renders the interpretation of the electronic band structure obscure, making it difficult to chemically guide band engineering and optimization efforts. In this work, we delineate the valence balanced Zintl chemistry of A14MX11 compounds (A = Yb, Ca; M = Mg, Mn, Al, Zn, Cd; X = Sb, Bi) using molecular orbital theory analysis. By analyzing the electronic band structures of Yb14MgSb11 and Yb14AlSb11 , we show that the conduction band minimum is composed of either an antibonding molecular orbital originating from the (Sb3)7− trimer, or a mix of atomic orbitals of A, M, and X. The singly degenerate valence band is comprised of non-bonding Sb p-z orbitals primarily from the Sb atoms in the (MSb4)m- tetrahedra and the of isolated Sb atoms distributed throughout the unit cell. Such a chemical understanding of the electronic structure enables strategies to engineer electronic properties (e.g., the band gap) of A14MX11 compounds.

High thermoelectric performance of single phase p-type cerium-filled skutterudites by dislocation engineering

2018 ◽  
Vol 6 (41) ◽  
pp. 20128-20137 ◽  
Author(s):  
Xianfu Meng ◽  
Yuan Liu ◽  
Bo Cui ◽  
Dandan Qin ◽  
Jian Cao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Power Generation ◽  
Power Factor ◽  
High Power ◽  
Single Phase ◽  
Intermediate Temperature ◽  
Thermoelectric Performance ◽  
High Power Factor ◽  
Filled Skutterudites ◽  
P Type

Filled skutterudites, possessing a high power factor and good mechanical properties, have attracted intensive attention for the intermediate-temperature power generation.

Intermetallic M Pt3 (M = Ti, Zr, Hf): Elastic, electronic, optical and thermal properties

2019 ◽  
Vol 33 (18) ◽  
pp. 1950189 ◽  
Author(s):  
S. K. Mitro ◽  
M. A. Rahman ◽  
F. Parvin ◽  
A. K. M. A. Islam
Keyword(s):  
Thermal Properties ◽  
Elevated Temperatures ◽  
Visible Region ◽  
Debye Model ◽  
Mechanical And Thermal Properties ◽  
Electronic Band ◽  
Thermal Expansion Coefficients ◽  
High Thermal Expansion ◽  
Expansion Coefficients ◽  
Electronic Band Structures

In this study, the structural and unexplored elastic, electronic, optical and thermal properties of Pt-based alloys MPt3 (M = Ti, Hf) and only optical and thermal properties of ZrPt3 are subjected to investigation using the method of the first principles. The results of pressure dependence of mechanical and thermal properties are discussed. The electronic band structures and density of state data show metallic conductivity for all the compounds. The main contribution at Fermi level comes from Ti 3d and Zr 4d (for TiPt3 and ZrPt[Formula: see text] and Pt 5d (for HfPt[Formula: see text] orbitals. The materials’ optical reflectivity values, relatively high in the IR-visible-UV regions, range from [Formula: see text]62% to 72% in the visible region which show better performance values in comparison to those of some representative materials PtAl2, AuAl2 and GdX3 (X = In, Sn, Tl, Pb). The unexplored thermal behaviors are also investigated via quasi-harmonic Debye model at T = 0 and P = 0 as well as at elevated temperatures and pressures. In addition, when used as bonding materials, studied intermetallics with moderately high thermal expansion coefficients can match other substrates. This coupled with the estimated thermal conductivities (k[Formula: see text]) compared to several other species indicate that the intermetallics can be used in applications, such as thermal barrier coatings (TBC). This study has thus indicated possible alternative candidates for high-temperature applications which would initiate further research and development on the intermetallics under study.

Electronic band structures of NdFe3(BO3)4 and NdGa3(BO3)4 crystals: ab initio calculations

2021 ◽  
Vol 575 (1) ◽  
pp. 11-17
Author(s):  
S. Krylova ◽  
I. Gudim ◽  
A. Aleksandrovsky ◽  
A. Vtyurin ◽  
A. Krylov
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Band Structures ◽  
Electronic Band ◽  
Electronic Band Structures

Tailored Electronic Band Gap and Valance Band Edge of Nickel Oxide via p-Type Incorporation

2021 ◽  
Vol 125 (13) ◽  
pp. 7495-7501
Author(s):  
Gang Wang ◽  
Jinju Zheng ◽  
Boyi Xu ◽  
Chaonan Zhang ◽  
Yue Zhu ◽  
...  
Keyword(s):  
Nickel Oxide ◽  
Band Gap ◽  
Band Edge ◽  
Electronic Band ◽  
Electronic Band Gap ◽  
P Type

scholarly journals Phase-selective active sites on ordered/disordered titanium dioxide enable exceptional photocatalytic ammonia synthesis

2021 ◽  
Author(s):  
Jinsun Lee ◽  
Xinghui Liu ◽  
Ashwani Kumar ◽  
Yosep Hwang ◽  
Eunji Lee ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Active Sites ◽  
Rational Design ◽  
Ammonia Synthesis ◽  
Reduction Reaction ◽  
Band Structures ◽  
Electronic Band ◽  
Defect Sites ◽  
Electronic Band Structures ◽  
Reaction Routes

This work highlights the importance of a rational design for more energetically suitable nitrogen reduction reaction routes and mechanisms by regulating the electronic band structures with phase-selective defect sites.

Molecular Vibrations in the Exciton Theory for Molecular Aggregates. II. Dimeric Systems

1961 ◽  
Vol 14 (3) ◽  
pp. 344 ◽  
Author(s):  
EG McRae
Keyword(s):  
Absorption Spectrum ◽  
Perturbation Theory ◽  
Fluorescence Spectra ◽  
Numerical Calculations ◽  
Molecular Vibrations ◽  
Molecular Aggregates ◽  
Absorption And Fluorescence Spectra ◽  
Band Structures ◽  
Electronic Band ◽  
Electronic Band Structures

The theory of Part I of this series (McRae 1961) is developed in detail for dimeric systems. The simplest possible theory of the exciton states for a system of two non-rigid molecules is obtained through the use of perturbation theory. The theory makes possible the prediction of electronic band structures in absorption and fluorescence spectra as functions of the theoretical Davydov splitting for two rigid molecules. Numerical calculations are made for a dimer of a typical dye, and the results are compared with the observed absorption spectrum of the 1,1'-diethyl-2,2'-pyridocyanine iodide dimer.

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