Thermoelectric properties control of Half-Heusler compounds by lattice defects and interfaces introduced based on the close relationship with Heusler compounds

2015 ◽  
Vol 1760 ◽  
Author(s):  
Yoshisato Kimura ◽  
Yaw-Wang Chai ◽  
Toshinori Oniki ◽  
Takahiko Itagaki ◽  
Shinya Otani
Keyword(s):  
Seebeck Coefficient ◽  
Lattice Defects ◽  
Heusler Compounds ◽  
Nano Structure ◽  
Heusler Phase ◽  
Site Occupation ◽  
Seebeck Coefficients ◽  
Close Relationship ◽  
Vacancy Site ◽  
P Type

ABSTRACTHalf-Heusler MNiSn (M=Ti, Zr, Hf) compounds are well-known, excellent n-type thermoelectric materials. The n-type Seebeck coefficients of ZrNiSn are reduced because of the precipitation of the metallic Heusler ZrNi2Sn phase. An excellent n-type Seebeck coefficient can be converted to p-type based on the vacancy site occupation by the solute Co atoms in the half-Heusler TiNiSn phase as well as ZrNiSn. The Heusler phase precipitates, including their precursor nano-structure in the half-Heusler matrix and the vacancy site occupation of the half-Heusler phase, are regarded as lattice defects based on the crystallographically and thermodynamically close relationship between half-Heusler and Heusler phases.

Investigation of the Properties of Electrochemically Deposited Semiconductor Materials for Thermoelectric Applications

2003 ◽  
Vol 793 ◽  
Author(s):  
C.-K. Huang ◽  
J.A. Herman ◽  
N. Myung ◽  
J. R. Lim ◽  
J.-P. Fleurial
Keyword(s):  
Seebeck Coefficient ◽  
Transport Properties ◽  
Carrier Concentration ◽  
Direction Parallel ◽  
Seebeck Coefficients ◽  
Before And After ◽  
Electrochemically Deposited ◽  
High Seebeck Coefficient ◽  
Preliminary Study ◽  
P Type

ABSTRACTAt JPL, it is our desire to fabricate thermoelectric micro-devices for power generation and cooling applications using an electrochemical deposition (ECD) technique. We believe that the performance of our current micro-device developed is limited by the properties of the ECD materials. Therefore, the objective of this study is to develop ECD methods for obtaining n-type Bi2Te3 and p-type Bi2-xSbxTe3 thermoelectric materials with near bulk properties, as well as optimizing morphology and transport properties. The films of Bi2Te3 and Bi2-xSbxTe3 were initially obtained under various ECD conditions. Seebeck coefficients and transport properties were then measured along the direction parallel to the substrates before and after annealing at 250°C for 2hrs. From the data obtained, ECD n-Bi2Te3 material can achieve a high Seebeck coefficient (-189 μV/K) when it is deposited at –200 mV vs. SCE. The in-plane resistivity, in-plane mobility, and carrier concentration are 3.0 mohm-cm, 31 cm2 V−1 S−1, and 6.79 × 1019 cm−3, respectively. As for the p-type Bi2-xSbxTe3, it is possible to achieve a high Seebeck coefficient (+295 μV/K) when it is deposited at 0.3 mA/cm2. The in-plane resistivity, in-plane mobility, and carrier concentration are 9.8374 mohm-cm, 66.58 cm2 V−1 S−1, and 9.54 × 1018 cm−3, respectively. From the results of our preliminary study, we have found the conditions for depositing high quality Bi2Te3 and Bi2-xSbxTe3 materials with thermoelectric properties comparable to those of their state-of-the-art bulk samples.

Band Structures and Transport Properties of Half-Heusler Compounds NbMSb (M = Fe, Ru)

2016 ◽  
Vol 847 ◽  
pp. 171-176
Author(s):  
Teng Fang ◽  
Shu Qi Zheng ◽  
Hong Chen ◽  
Peng Zhang
Keyword(s):  
Transport Properties ◽  
Valence Band Maximum ◽  
Thermoelectric Generators ◽  
Heusler Compounds ◽  
Boltzmann Transport ◽  
Band Structures ◽  
Seebeck Coefficients ◽  
Electrical Conductivities ◽  
Scattering Time ◽  
P Type

The band structures and transport properties of Half-Heusler compounds NbFeSb and NbRuSb were studied using ab initio calculations and the Boltzmann transport equation with constant scattering time approximation (CSTA). Both compounds were identified as good p-type thermoelectric materials because of the combination of heavy and light bands in the valence band maximum (VBM). The Seebeck coefficients for NbRuSb were lower than that for NbFeSb; while the electrical conductivities for NbRuSb were little higher than that for NbFeSb. Consequently, the power factors in the p-type regimes for both compounds were similar at a given temperature. NbFeSb and NbRuSb could be efficient materials for thermoelectric generators based on the results in the present investigation.

scholarly journals Thermoelectric Performance of Polypropylene/Carbon Nanotube/Ionic Liquid Composites and Its Dependence on Electron Beam Irradiation

2022 ◽  
Vol 6 (1) ◽  
pp. 25
Author(s):  
Oliver Voigt ◽  
Beate Krause ◽  
Petra Pötschke ◽  
Michael T. Müller ◽  
Sven Wießner
Keyword(s):  
Electron Beam ◽  
Seebeck Coefficient ◽  
Electron Beam Irradiation ◽  
Single Walled Carbon Nanotubes ◽  
Electron Beam Treatment ◽  
Beam Irradiation ◽  
Seebeck Coefficients ◽  
Treated Sample ◽  
P Type ◽  
Walled Carbon Nanotubes

The thermoelectric behavior of polypropylene (PP) based nanocomposites containing single walled carbon nanotubes (SWCNTs) and five kinds of ionic liquids (Ils) dependent on composite composition and electron beam irradiation (EB) was studied. Therefore, several samples were melt-mixed in a micro compounder, while five Ils with sufficiently different anions and/or cations were incorporated into the PP/SWCNT composites followed by an EB treatment for selected composites. Extensive investigations were carried out considering the electrical, thermal, mechanical, rheological, morphological and, most significantly, thermoelectric properties. It was found that it is possible to prepare n-type melt-mixed polymer composites from p-type commercial SWCNTs with relatively high Seebeck coefficients when adding four of the selected Ils. The highest Seebeck coefficients achieved in this study were +49.3 µV/K (PP/2 wt.% SWCNT) for p-type composites and −27.6 µV/K (PP/2 wt.% SWCNT/4 wt.% IL type AMIM Cl) for n-type composites. Generally, the type of IL is decisive whether p- or n-type thermoelectric behavior is achieved. After IL addition higher volume conductivity could be reached. Electron beam treatment of PP/SWCNT leads to increased values of the Seebeck coefficient, whereas the EB treated sample with IL (AMIM Cl) shows a less negative Seebeck coefficient value.

Improving the thermoelectric performance of p-type PbSe via synergistically enhancing the Seebeck coefficient and reducing electronic thermal conductivity

2020 ◽  
Vol 8 (9) ◽  
pp. 4931-4937 ◽  
Author(s):  
Zhiwei Huang ◽  
Dongyang Wang ◽  
Caiyun Li ◽  
Jinfeng Wang ◽  
Guangtao Wang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Performance ◽  
Seebeck Coefficients ◽  
Electronic Thermal Conductivity ◽  
P Type

CdTe alloying dramatically enhanced the thermoelectric performance of p-type PbSe by enhancing Seebeck coefficients and reducing electronic thermal conductivity.

The Effect of Rh and Sr Substitution on the Thermoelectric Performance of LaCoO3

2010 ◽  
Vol 1267 ◽  
Author(s):  
Kyei-Sing Kwong ◽  
Andrew E Smith ◽  
Mas Subramanian
Keyword(s):  
Crystal Structure ◽  
Seebeck Coefficient ◽  
Figure Of Merit ◽  
Thermoelectric Performance ◽  
Component System ◽  
Temperature Range ◽  
Seebeck Coefficients ◽  
Lower Temperature Range ◽  
Lower Temperature ◽  
P Type

AbstractA series of LaCo1-xRhxO3 (x=0-1) samples and La1-ySryCo1-xRhxO3 (y = 0.05, 0.15 and x = 0.1-0.3) samples were prepared to study the effect of Rh substituion for Co in the four component system and Sr substitution for La in the five component system on the crystal structure and thermoelectric performance of the LaCoO3. At Rh substitution for Co of x=0.2 greater, the crystal structure shifts from rhombohederal (LaCoO3) to orthorhombic (LaRhO3). Thermoelectric evaluation revealed that Rh doped samples (0.3 <x <1) show large positive seebeck coefficients indicating a P-type conduction in the temperature range of the tests (273 to 775K). Rh substitution for Co decreases thermal conductivity, increases Seebeck coefficient and consequently increases the theroelectric figure of merit ZT. Sr substitution for La increases thermal and electrical conductivity and consquenently negligiblely decreases the seebeck coefficient. A thermoelectric figure-of-merit (ZT) around 0.075 has been achieved for LaCo0.5Rh0.5O3 at 775 K, and is expected to be above 0.1 at 1000 K. Sr substitution improved the TE properties throughout the lower temperature range with a ZT =0.045 observed for La0.95Sr0.05Co0.9Rh0.1O3 at 425 K and ZT = 0.05 for La0.85Sr0.15Co0.5Rh0.5O3 at 775 K. These findings provide new insight into thermoelectric perovskite oxides containing rhodium and strontium.

A Study on the Seebeck Effect of 3,4,9,10-Perylenetetracarboxylic Dianhydride (PTCDA) as a Novel N-Type Material in a Thermoelectric Device

2013 ◽  
Vol 667 ◽  
pp. 165-171
Author(s):  
Zurianti A. Rahman ◽  
Khaulah Sulaiman ◽  
Mohamad Rusop ◽  
Ahmad Shuhaimi
Keyword(s):  
Thermal Treatment ◽  
Seebeck Coefficient ◽  
Output Power ◽  
Open Circuit Voltage ◽  
Open Circuit ◽  
Seebeck Effect ◽  
Type Material ◽  
Thermoelectric Device ◽  
Seebeck Coefficients ◽  
P Type

The studies on the thermoelectric (TE) properties of 3,4,9,10-Perylenetetracarboxylic dianhydride (PTCDA) and a conducting polymer Poly(ethylenedioxythiopene): poly(styrenesulfonate) (PEDOT:PSS)–PH1000 are presented. PTCDA and PEDOT:PSS have been used as a potential n-type material and a p-type material for the TE device, respectively. The Seebeck coefficients, open circuit voltage and the output power have been obtained for the fabricated TE device. The Seebeck effect was observed on this TE device where the output power in the range of 1 nW/cm2 to 5 nW/cm2,was successfully deduced from this TE device. It was found that the association of PEDOT:PSS and PTCDA have been acting well in this TE device. However, a higher TE performance, in the future could be developed, by applying a thermal treatment and introducing a suitable dopant to this n-type material which may increase the mobility of the electrons and the Seebeck coefficient.

Effect of Vacancy-Site Occupation in Half-Heusler Compound ZrNiSn on Phase Stability and Thermoelectric Properties

2011 ◽  
Vol 1295 ◽  
Author(s):  
Yoshisato Kimura ◽  
Toshiyasu Tanoguchi ◽  
Yasuhiro Sakai ◽  
Yaw-Wang Chai ◽  
Yoshinao Mishima
Keyword(s):  
Phase Stability ◽  
Phonon Scattering ◽  
Stoichiometric Composition ◽  
Two Phase ◽  
Metallic Behavior ◽  
Heusler Compound ◽  
Heusler Phase ◽  
Vacancy Site ◽  
Co Addition ◽  
P Type

ABSTRACTThe half-Heusler compound ZrNiSn has a quite small solubility for Ni from the stoichiometric composition towards the Ni-rich direction since Ni atoms are not supposed to occupy the vacancy-site. Nevertheless, Co and Ir atoms preferably occupy the vacancy-site of ZrNiSn, which is contrary to the prediction that they would substitute for Ni sites. This implies that the phase stability of the compound gradually changes toward that of the Heusler compound Zr(Ni,M)2Sn (M = Co, Ir). It has been confirmed that there exists a two-phase field between half-Heusler Zr(Ni,Cox)Sn and Heusler Zr(Ni,Co)2Sn. The n-type thermoelectric property of ZrNiSn can be converted to p-type by the addition of Co and Ir within the compositional range of the half-Heusler phase. The occupation of vacancy sites by Co and Ir atoms leads to a drastic reduction in the thermal conductivity owing to the enhancement of phonon scattering. With further Co addition, the Heusler phase Zr(Ni,Co)2Sn alloys show metallic behavior.

scholarly journals Screening of Different Carbon Nanotubes in Melt-Mixed Polymer Composites with Different Polymer Matrices for Their Thermoelectrical Properties

2019 ◽  
Vol 3 (4) ◽  
pp. 106 ◽  
Author(s):  
Beate Krause ◽  
Carine Barbier ◽  
Juhasz Levente ◽  
Maxim Klaus ◽  
Petra Pötschke
Keyword(s):  
Seebeck Coefficient ◽  
Polymer Composites ◽  
Power Factor ◽  
Vinylidene Fluoride ◽  
Small Scale ◽  
Polyamide 66 ◽  
Direct Production ◽  
Seebeck Coefficients ◽  
P Type ◽  
Walled Cnts

The aim of this study is to reveal the influences of carbon nanotube (CNT) and polymer type as well as CNT content on electrical conductivity, Seebeck coefficient (S), and the resulting power factor (PF) and figure of merit (ZT). Different commercially available and laboratory made CNTs were used to prepare melt-mixed composites on a small scale. CNTs typically lead to p-type composites with positive S-values. This was found for the two types of multi-walled CNTs (MWCNT) whereby higher Seebeck coefficient in the corresponding buckypapers resulted in higher values also in the composites. Nitrogen doped MWCNTs resulted in negative S-values in the buckypapers as well as in the polymer composites. When using single-walled CNTs (SWCNTs) with a positive S-value in the buckypapers, positive (polypropylene (PP), polycarbonate (PC), poly (vinylidene fluoride) (PVDF), and poly(butylene terephthalate) (PBT)) or negative (polyamide 66 (PA66), polyamide 6 (PA6), partially aromatic polyamide (PARA), acrylonitrile butadiene styrene (ABS)) S-values were obtained depending on the matrix polymer and SWCNT type. The study shows that the direct production of n-type melt-mixed polymer composites from p-type commercial SWCNTs with relatively high Seebeck coefficients is possible. The highest Seebeck coefficients obtained in this study were 66.4 µV/K (PBT/7 wt % SWCNT Tuball) and −57.1 µV/K (ABS/0.5 wt % SWCNT Tuball) for p- and n-type composites, respectively. The highest power factor and ZT of 0.28 µW/m·K2 and 3.1 × 10−4, respectively, were achieved in PBT with 4 wt % SWCNT Tuball.

INFLUENCE OF SILICON ADDITION ON SEEBECK COEFFICIENT OF MnSi1.7 FILMS

2011 ◽  
Vol 25 (18) ◽  
pp. 2393-2402 ◽  
Author(s):  
Q. R. HOU ◽  
B. F. GU ◽  
Y. B. CHEN ◽  
Y. J. HE
Keyword(s):  
Electrical Resistivity ◽  
Film Thickness ◽  
Seebeck Coefficient ◽  
Room Temperature ◽  
Electron Beam Evaporation ◽  
Aluminum Layer ◽  
Seebeck Coefficients ◽  
Thin Aluminum ◽  
Increasing Temperature ◽  
P Type

MnSi 1.7 films with different thicknesses (16–242 nm) are prepared by magnetron sputtering and electron beam evaporation. When the MnSi 1.7 film thickness is about 40 nm or above, MnSi 1.7 films are p-type in the whole temperature range (300–700 K) in agreement with reports in literature. By co-sputtering of MnSi 1.85 and silicon targets or deposition of Si / Mn multi-layers with a larger thickness ratio, silicon is added to the films and the Seebeck coefficients transform from positive to negative with increasing temperature. The Seebeck coefficients at room temperature and 633 K are +0.098 mV/K and -0.358 mV/K, respectively. By reducing the MnSi 1.7 film thickness to 27 nm, the transition of Seebeck coefficient from positive to negative is also observed although silicon is not added intentionally. When an ultra-thin aluminum layer is deposited between MnSi x(x < 1.7) and Si layers to enhance silicon diffusion, the p- to n-type transition temperature decreases about 100 K. The silicon-added MnSi 1.7 films usually have higher electrical resistivity.

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