scholarly journals Charge Transport and Thermoelectric Properties of Mn-Doped Tetrahedrites Cu12-xMnxSb4S13

2021 ◽  
Vol 59 (5) ◽  
pp. 329-335
Author(s):  
Sung-Yoon Kim ◽  
Go-Eun Lee ◽  
Il-Ho Kim

Mn-doped tetrahedrites Cu12-xMnxSb4S13 (0.1 ≤ x ≤ 0.4) were synthesized by mechanical alloying (MA) and sintered by hot pressing (HP). A single tetrahedrite phase was synthesized by MA without post-annealing, and it was stable without any phase changes after HP. The hot-pressed specimens had a relative density higher than 98.6%. The lattice constant of the Mn-doped samples increased compared to that of undoped Cu12Sb4S13, but no significant change in the lattice constant was observed with a change in Mn content. All Mn-doped tetrahedrites acted as p-type semiconductors, as confirmed from positive Hall and Seebeck coefficient values. The Seebeck coefficient increased with increasing temperature but decreased with increasing Mn content; maximum Seebeck coefficient values of 200−219 μVK-1 were obtained at 323−723 K for x = 0.1. Electrical conductivity increased with increasing temperature and Mn content; the highest electrical conductivity values of (1.76−2.45) × 104 Sm-1 were obtained at 323−723 K for x = 0.4. As a result, Cu11.6Mn0.4Sb4S13 exhibited a maximum power factor of 0.80 mWm-1K-2 at 723 K. As the Mn content increased, both the electronic and lattice thermal conductivities increased, and thus, the total thermal conductivity was the lowest at 0.48–0.63Wm-1K-1 at 323–723 K for x = 0.1. A maximum dimensionless figure of merit of 0.75 was obtained at 723 K for Cu11.7Mn0.3Sb4S13. The MA-HP process is suitable for preparing doped tetrahedrites exhibiting excellent thermoelectric performance.

1987 ◽  
Vol 97 ◽  
Author(s):  
C. Wood ◽  
D. Emin ◽  
R. S. Feigelson ◽  
I. D. R. Mackinnon

ABSTRACTMeasurements of the electrical conductivity, Seebeck coefficient and Hall mobility from -300 K to -1300 K have been carried out on multiphase hotpressed samples of the nominal composition B6Si. In all samples the conductivity and the p-type Seebeck coefficient both increase smoothly with increasing temperature. By themselves, these facts suggest small-polaronic hopping between inequivalent sites. The measured Hall mobilities are always low, but vary in sign. A possible explanation is offered for this anomalous behavior.


2013 ◽  
Vol 1490 ◽  
pp. 33-40
Author(s):  
Song Zhu ◽  
Satish Vitta ◽  
Terry M. Tritt

ABSTRACTTi-Ni-Sn type half-Heusler alloys which have the versatility to be either p- or n-type depending on the type of substitution, have been synthesized and investigated in the present work. The added advantage of doping them with multiple elements is that they will be amenable to bulk amorphous phase formation. The hole doped alloys were predominantly single phase with a cubic structure, while the electron doped alloys were found to have minor additional phases. All the alloys exhibit extremely weak metallic-like or degenerate semiconductor transport behaviour in the temperature range 20 K to 1000 K. The resistivity of p-type alloys exhibits semi-metallic-to-semiconducting transition at ∼ 500 K while the n-type alloys exhibit a weak metallic-like behaviour in the complete temperature range. The Seebeck coefficient has strong temperature dependence with a maximum of 45 μV K−1 in the temperature range 600-700 K in the p-type alloys. The n-type alloys however exhibit a linear variation of the Seebeck coefficient with temperature. The total thermal conductivity of the alloys increases with increasing temperature without any peak at low temperatures indicating significant disorder induced scattering. The p-type alloys have the lowest thermal conductivity compared to the n-type alloys. These alloys become amorphous after pulsed laser deposition except one alloy which exhibits compensated transport behaviour.


2014 ◽  
Vol 602-603 ◽  
pp. 906-909 ◽  
Author(s):  
Yao Chun Liu ◽  
Jun Fu Liu ◽  
Bo Ping Zhang ◽  
Yuan Hua Lin

We report on the effect of Ni doping on the thermoelectric properties of p-type BiCuSeO oxyselenide, with layer structure composed of conductive (Cu2Se2)2-layers alternately stacked with insulating (Bi2O2)2+layers along c axis. After doping with Ni, enhanced electrical conductivity coupled with a moderate Seebeck coefficient leads to a power factor of ~231 μwm-1K-2at 873 K. Coupled to low thermal conductivity, ZT at 873 K is increased from 0.35 for pristine BiCuSeO to 0.39 for Bi0.95Ni0.05CuSeO. However, the efficiency of Ni doping in the insulating (Bi2O2)2+layer is low, and this doping only leads to a limited increase of the hole carriers concentration. Therefore Ni doped BiCuSeO has relatively low electrical conductivity which makes its thermoelectric figure of merit much lower than that of Ca, Sr, Ba and Pb doped BiCuSeO.


2007 ◽  
Vol 1044 ◽  
Author(s):  
Mi-kyung Han ◽  
Huijun Kong ◽  
Ctirad Uher ◽  
Mercouri G Kanatzidis

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).


1998 ◽  
Vol 545 ◽  
Author(s):  
Ke-Feng Cai ◽  
Ce-Wen Nan ◽  
Xin-Min Min

AbstractB4C ceramics doped with various content of Si (0 to 2.03 at%) are prepared via hot pressing. The composition and microstructure of the ceramics are characterized by means of XRD and EPMA. Their electrical conductivity and Seebeck coefficient of the samples are measured from room temperature up to 1500K. The electrical conductivity increases with temperature, and more rapidly after 1300K; the Seebeck coefficient of the ceramics also increases with temperature and rises to a value of about 320μVK−1. The value of the figure of merit of Si-doped B4C rises to about 4 × 10−4K−1 at 1500K.


Author(s):  
А.А. Шабалдин ◽  
П.П. Константинов ◽  
Д.А. Курдюков ◽  
Л.Н. Лукьянова ◽  
А.Ю. Самунин ◽  
...  

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.


2008 ◽  
Vol 368-372 ◽  
pp. 547-549
Author(s):  
Jun Jiang ◽  
Ya Li Li ◽  
Gao Jie Xu ◽  
Ping Cui ◽  
Li Dong Chen

In the present study, n-type (Bi2Se3)x(Bi2Te3)1-x crystals with various chemical compositions were fabricated by the zone melting method. Thermoelectric properties, including Seebeck coefficient (α), electrical conductivity (σ) and thermal conductivity (κ), were measured in the temperature range of 300-500 K. The influence of the variations of Bi2Te3 and Bi2Se3 content on thermoelectric properties was studied. The increase of Bi2Se3 content (x) caused an increase in carrier concentration and thus an increase of σ and a decrease of α. The maximum figure of merit (ZT = α2σT/κ) of 0.87 was obtained at about 325 K for the composition of 93%Bi2Te3-7%Bi2Se3 with doping TeI4.


Crystals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 140 ◽  
Author(s):  
Ji Hoon Kim ◽  
Seunggun Yu ◽  
Sang Won Lee ◽  
Seung-Yong Lee ◽  
Keun Soo Kim ◽  
...  

Recently, two-dimensional tungsten disulfide (WS2) has attracted attention as a next generation thermoelectric material due to a favorable Seebeck coefficient. However, its thermoelectric efficiency still needs to be improved due to the intrinsically low electrical conductivity of WS2. In the present study, thermoelectric properties of WS2 hybridized with highly conductive single-walled carbon nanohorns (SWCNHs) were investigated. The WS2/SWCNH nanocomposites were fabricated by annealing the mixture of WS2 and SWCNHs using a high-frequency induction heated sintering (HFIHS) system. By adding SWCNHs to WS2, the nanocomposites exhibited increased electrical conductivity and a slightly decreased Seebeck coefficient with the content of SWCNHs. Hence, the maximum power factor of 128.41 μW/mK2 was achieved for WS2/SWCNHs with 0.1 wt.% SWCNHs at 780 K, resulting in a significantly improved thermoelectric figure of merit (zT) value of 0.027 compared to that of pristine WS2 with zT 0.017.


2001 ◽  
Vol 16 (12) ◽  
pp. 3343-3346 ◽  
Author(s):  
X. F. Tang ◽  
L. M. Zhang ◽  
R. Z. Yuan ◽  
L. D. Chen ◽  
T. Goto ◽  
...  

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.


2011 ◽  
Vol 695 ◽  
pp. 65-68 ◽  
Author(s):  
Kwan Ho Park ◽  
Il Ho Kim

Co4-xFexSb12-ySny skutterudites were synthesized by mechanical alloying and hot pressing, and thermoelectric properties were examined. The carrier concentration increased by doping and thereby the electrical conductivity increased compared with intrinsic CoSb3. Every specimen had a positive Seebeck coefficient. Fe doping caused a decrease in the Seebeck coefficient but it could be enhanced by Fe/Sn double doping possibly due to charge compensation. The thermal conductivity was desirably very low and this originated from ionized impurity-phonon scattering. Thermoelectric properties were improved remarkably by Fe/Sn doping, and a maximum figure of merit, ZT = 0.5 was obtained at 723 K in the Co3FeSb11.2Sn0.8 specimen.


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