scholarly journals Термоэлектрические свойства твердых растворов (CuInSe-=SUB=-2-=/SUB=-)-=SUB=-1-x-=/SUB=-(In-=SUB=-2-=/SUB=-Te-=SUB=-3-=/SUB=-)-=SUB=-x-=/SUB=-

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.

2020 ◽  
Vol 62 (4) ◽  
pp. 537
Author(s):  
А.В. Сотников ◽  
В.В. Баковец ◽  
Michihiro Ohta ◽  
А.Ш. Агажанов ◽  
С.В. Станкус

The temperature dependences of Seebeck coefficient, electrical conductivity (Т=300–873K), thermal conductivity and figure of merit (Т=300–770K) of polycrystalline samples of solid solutions based on gadolinium and dysprosium sulfides with γ-GdxDy1-xS1.49 (x=0.1, 0.2, 0.3, 0.4) composition were studied. It was established that samples morphological features, namely, the specific surface area of crystallites causing a change in the number of deformation centers determines the thermal conductivity of -GdxDy1-xS1.49, and it was found that there is an anomalous decrease in thermal conductivity for composition with х = 0.2. For this composition the lowest values of Seebeck coefficient -371 mkV/K at 873K, electrical resistivity 880 mkΩ∙m at 873K and thermal conductivity 0.68 ± 0.03 W/m·K at 770K were obtained, in this case the thermoelectric figure of merit reaches ZT = 0.23.


2021 ◽  
Vol 23 (5) ◽  
pp. 243-246
Author(s):  
D.G. Mustafaeva ◽  

The area of practical application of thermoelectric materials depends on the value of the thermoelectric figure of merit. The use of semiconductor materials makes it possible to realize the conditions under which the ratio of their parameters ensures the achievement of high values of thermoelectric figure of merit. The achievement of the maximum thermoelectric figure of merit causes an increase in the efficiency of conversion processes due to the improvement of the thermoelectric properties of the material. The position of the maximum value of the thermoelectric figure of merit is predetermined by the scattering parameters and the ratio of the mobilities and effective masses of charge carriers. The nature of the change in electrical conductivity is determined by the behavior of the concentration of charge carriers. Thermal conductivity, like electrical conductivity, is proportional to the concentration of electrons and the mean free path. An increase in thermoelectric efficiency is achieved by optimizing thermoelectric parameters by doping and improving the properties of com¬pounds, which leads to an optimization of the concentration of charge carriers, a change in the density of states, and a decrease in the phonon component of thermal conductivity. The improvement of the thermoelectric properties of the material and the increase in the efficiency of the conversion processes are provided at a certain concentration of charge carriers, which corresponds to the optimal value.


Author(s):  
Г.Н. Исаченко ◽  
А.Ю. Самунин ◽  
П.П. Константинов ◽  
А.А. Касьянов ◽  
А. Масалимов

AbstractHigh values of the thermoelectric figure of merit ( ZT = 1.5) in Mg_2Si–Mg_2Sn solid solutions are caused by a low thermal conductivity and a complex band structure, which is optimal at the ratio of solid-solution components of 40% Mg_2Si and 60% Mg_2Sn. However, the presence of magnesium stannide in a high concentration impairs the mechanical properties and chemical stability of the material limiting its application at high temperatures. Magnesium silicide has a higher stability but a lower figure of merit. The figure of merit is much lower in Mg_2Si-rich solid solutions and amounts to ZT ~ 1. The possibility of increasing ZT in the Mg_2Si_0.8Sn_0.2 solid solution with the additional inclusion of Mg_2Ge in small quantities is investigated here. Samples of Mg_2(Si_1 –_ x Ge_ x )_0.8Sn_0.2 ( x < 0.03) solid solution are prepared by hot pressing. The temperature dependences of the coefficients of the thermoelectric power, electrical conductivity, and thermal conductivity are measured in the range of 300–800 K. An increase in the thermoelectric figure of merit to ZT = 1.1 is shown at T = 800 K in the Mg_2Si_0.78Ge_0.02Sn_0.2〈Sb〉 solid solution.


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.


2012 ◽  
Vol 519 ◽  
pp. 188-192 ◽  
Author(s):  
P.Z. Ying ◽  
H. Zhou ◽  
Y.L. Gao ◽  
Y.Y. Li ◽  
Y.P. Li ◽  
...  

Here we report the thermoelectric properties of a wide–gap chalcopyrite compound AgInSe2, and observed the remarkable improvement in electrical conductivity σ, due to the bandgap (Eg = 1.12 eV) reduction compared to In2Se3. The improvement in σ is directly responsible for the enhancement of thermoelectric figure of merit ZT, though the thermal conductivity is much higher at 500 ~ 724 K. The maximum ZT value is 0.34 at 724 K, increasing by a factor of 4, indicating that this chalcopyrite compound is of a potential thermoelectric candidate if further optimizations of chemical compositions and structure are made.


2018 ◽  
Vol 913 ◽  
pp. 811-817 ◽  
Author(s):  
Di Wu ◽  
Ji Ai Ning ◽  
De Gang Zhao ◽  
Xue Zhen Wang ◽  
Na Liu

In this study, nanometer WO3 powder was uniformly dispersed into the Cu2SnSe3 powder by ball milling process, and the WO3/Cu2SnSe3 thermoelectric composite was prepared by spark plasma sintering (SPS). The results showed that the nano-WO3 particles were mainly distributed in the grain boundary of Cu2SnSe3 matrix, and the grain growth of Cu2SnSe3 was inhibited. The addition of nano-WO3 could enhance the electrical conductivity of Cu2SnSe3, and while the Seebeck coefficient increased slightly for the 0.4% WO3/Cu2SnSe3 composite. The thermal conductivity was not decreased until the content of WO3 exceeded 1.6%. The highest thermoelectric figure of merit ZT of 0.177 was achieved at 700 K for 0.4% WO3/Cu2SnSe3 composite. The enhancement of ZT value of WO3/Cu2SnSe3 thermoelectric material was mainly attributed to the improvement of the electrical properties.


2016 ◽  
Vol 4 (9) ◽  
pp. 1871-1880 ◽  
Author(s):  
Gabin Guélou ◽  
Paz Vaqueiro ◽  
Jesús Prado-Gonjal ◽  
Tristan Barbier ◽  
Sylvie Hébert ◽  
...  

The thermoelectric figure of merit of TiS2 is increased by 25% through the intercalation of low levels of cobalt due to an increased electrical conductivity, arising from charge transfer, and a reduced thermal conductivity resulting from disorder.


2020 ◽  
Vol 8 (27) ◽  
pp. 13812-13819 ◽  
Author(s):  
Tribhuwan Pandey ◽  
Arun S. Nissimagoudar ◽  
Avanish Mishra ◽  
Abhishek K. Singh

We predict that mixed valent indium compounds exhibit a combination of high electrical conductivity, high thermopower, and low thermal conductivity, resulting in a large thermoelectric figure of merit.


2015 ◽  
Vol 16 (1) ◽  
pp. 62-67
Author(s):  
O. M. Matkivsky

An X-ray diffraction structural study and measurement of Seebeck coefficient (S), the electrical conductivity (σ) and thermal conductivity (χ) for Lead Telluride with nanoinclusions of ZnO. The calculated value of the specific thermoelectric power (S2σ) and thermoelectric figure of merit (ZT). It was established that the addition of ZnO powder Nanodispersed diameter grains (40-60) nm PbTe reduces the thermal conductivity of the material, and at 0.5 wt.% ZnO to an increase of lead telluride thermoelectric figure of merit to ZT≈1,3.


2000 ◽  
Vol 15 (2) ◽  
pp. 382-386 ◽  
Author(s):  
Woosuck Shin ◽  
Norimitsu Murayama

Electrical conductivity and thermopower of Bi2Sr3Co2Ox sintered bodies were first investigated in the temperature range 440–1060 K in air for high-temperature thermoelectric application. The samples fabricated by the sinter-forging method increased their bulk densities and electrical conductivity. The value of thermopower and the temperature dependence of electrical conductivity of the sinter-forged samples were close to that of the single crystal. Evaluating the thermal conductivity of the polycrystalline sample, we calculated a thermoelectric figure of merit Z to be 0.107 × 10−3 K−1 at 1060 K.


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