scholarly journals Combination of nanoparticles and carbon nanotubes for organic hybrid thermoelectrics

2020 ◽  
Vol 92 (6) ◽  
pp. 967-976
Author(s):  
Naoki Toshima ◽  
Yukihide Shiraishi

AbstractCarbon nanotubes (CNTs) are usually very expensive, but inexpensive CNTs have been mass-produced by a super-growth (SG) method. The SG-CNTs, however, have many defects resulting in a low conductivity, which is a disadvantage of the SG-CNTs. We discovered that even the defective SG-CNTs can provide a good thermoelectric performance by forming ternary hybrid films made of the SG-CNTs, nanoparticles (NPs) of a conducting polymer complex, poly(nickel 1,1,2,2-ethenetetrathiolate) (PETT) and poly(vinyl chloride) (PVC). The good thermoelectric performance of the ternary film (PETT-NP/SG-CNT/PVC) was possibly attributed to the defect repair effect in addition to the bridging effect of the PETT-NPs among the CNTs. In order to confirm this new concept, we attempted the deposition of metal NPs at the defects of the SG-CNTs. We initially made a physical mixture of palladium (Pd) NPs and the SG-CNTs in dispersions to cover the SG-CNT defects with the Pd-NPs. The obtained films showed only a slight improvement in electrical conductivity. Chemical reduction of the Pd ions in the dispersion of the SG-CNTs, on the other hand, provided hybrids with an enhanced electrical conductivity, thus, use as thermoelectric materials. The thermoelectric figure-of-merit was estimated to be ∼0.3, which is a relatively high value for organic hybrid materials.

2020 ◽  
Vol 1 (8) ◽  
pp. 2926-2936
Author(s):  
Keisuke Oshima ◽  
Yukihide Shiraishi ◽  
Takuya Matsumura ◽  
Ayumi Kuriyama ◽  
Kazuki Taguchi ◽  
...  

Pd nanoparticles can cover the defects of carbon nanotubes by a chemical reduction, which results in an increased carrier transport, then a high thermoelectric figure-of-merit, ZT = 0.3, in the sheets of the defect-repaired carbon nanotubes.


Author(s):  
Yongjun Jeon ◽  
Jae Gyu Jang ◽  
Sung Hyun Kim ◽  
Jong-In Hong

Twisted small organic molecules (SOMs) enhance the thermoelectric performance of single-walled carbon nanotubes (SWCNTs)/SOM hybrid films by dramatically increasing the Seebeck coefficient and minimising the inevitable reduction in electrical conductivity....


Author(s):  
Enamul Haque

This article reports the extraordinary thermoelectric figure of merit (ZT) of NaBaBi: degenerate bands, instead of the valley degeneracy of Bi2Te3, highly non-parabolic bands, and low DOS near the Fermi level of NaBaBi lead to an extraordinary ZTisotropic ≈ 1.60 at 350 K.


2020 ◽  
Vol 22 (4) ◽  
pp. 2081-2086 ◽  
Author(s):  
Taiki Tanishita ◽  
Koichiro Suekuni ◽  
Hirotaka Nishiate ◽  
Chul-Ho Lee ◽  
Michitaka Ohtaki

Co-substitution of Ge and P for Sb in Cu3SbS4 famatinite boosted dimensionless thermoelectric figure of merit.


RSC Advances ◽  
2016 ◽  
Vol 6 (115) ◽  
pp. 114825-114829 ◽  
Author(s):  
Tessera Alemneh Wubieneh ◽  
Cheng-Lung Chen ◽  
Pai Chun Wei ◽  
Szu-Yuan Chen ◽  
Yang-Yuan Chen

Ge doping enables to enhance the thermoelectric figure of merit of SnSe..


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.


Author(s):  
Ч.И. Абилов ◽  
М.Ш. Гасанова ◽  
Н.Т. Гусейнова ◽  
Э.К. Касумова

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.


2021 ◽  
Vol 26 (2) ◽  
pp. 123-131
Author(s):  
E.V. Morozova ◽  
◽  
D.A. Timkaeva ◽  

The hybrid systems based on the carbon nanotubes (CNT) and fullerenes (nanopipodes) are promising for applications in nanoelectronics. With insignificant variation of the CNT diameter the change of the fullerenes geometry takes place. The periodically located inside fullerenes represent a set of quantum points in the one-dimensional super-lattice. Using the variation of inside fullerenes it is possible to modulate the zone structure of the CNT – fullerene system and to control the electronic and phonon characteristics of nanopipodes. In the work the optical and thermoelectric properties of CNT with encapsulated molecules of C60 fullerene have been investigated. Using the first-principle methods the coefficients of absorption, optical conductivi-ty, thermal conductivity, thermoelectric figure of merit for CNT with fullerenes, periodically lo-cated inside the nanotubes at different distances from each other, have been calculated. It has been shown that with decreasing the distance between fullerenes the optical conductivity of CNT – C60 is suppressed at high frequencies. It has been determined that the conductance of the structures with fullerenes is less than the conductance of a clean tube, and approximately equal for considered distances (12.3 and 19.7 Å) between fullerenes. The CNT thermal conductivity due to the encapsulation of fullerenes considerably (3–4 times) decreases for the considered CNT (8.8) – C60 systems.


2020 ◽  
Vol 22 (26) ◽  
pp. 14621-14629 ◽  
Author(s):  
Suiting Ning ◽  
Shan Huang ◽  
Ziye Zhang ◽  
Renqi Zhang ◽  
Ning Qi ◽  
...  

The thermoelectric figure of merit (ZT) in LaPtBi shows an overall increase with increasing hydrostatic pressure.


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.


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