Papers by Keyword: Thermoelectric Material

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Authors: Shu Cai Zhou, Chen Guang Bai, Chun Lin Fu
Abstract: In order to reduce the oxidizing and volatilizing caused by Mg element in the traditional methods for synthesizing Mg2Sil-xSnx solid solutions, Mg2Sil-xSnx solid solutions have been prepared by Microwave-assisted Synthesis techniques. The heating behavior of Mg, Si and Sn fixed powder was investigated under microwave irradiation. X-ray diffraction (XRD) was used to characterize the powders. The results suggest that the temperature-rising rate is also dependent on the initial green density and higher green density provides lower heating rate while power setting are fixed. XRD patterns show that Mg2Sil-xSnx solid solutions have been well formed under microwave irradiation.
Authors: Yoshikazu Shinohara, Yoshio Imai, Yukihiro Isoda, Kentaro Hiraishi, Hachiro Nakanishi
Abstract: Typical conductive polymers of poly(3-alkylthiophenes) were synthesized by oxidative polymerization. Polythiophene with no side chain was also electrolyticaly polymerized. Alkyl side chains were CnH2n+1 with n=4, 6, 8, 12. The regioregularity with the HT linkage was larger than 99% based on NMR analysis. We have evaluated the effect of side chain size on the thermoelectric properties of Seebeck coefficient and electrical conductivity. The results were as follows: 1) Seebeck coefficient decreased with an increasing electrical conductivity. 2) High Seebeck coefficient >1mV/K was observed at low electrical conductivity <10-2S/cm. 3) Small side chains, especially no side chain caused higher thermoelectric properties of polythiophene series.
Authors: Ho Dong Yang, Hee Sung Yoon, Yool Kwon Oh
Abstract: This study investigated on cooling characteristics of thermoelectric cooling system using thermoelectric materials as Bi-Te alloy. The thermoelectric module used as thermoelectric materials of thermoelectric cooling system can achieve heating and cooling by change of electricity direction. When thermoelectric module and cooling fan received 12V from DC power source, the cooling region was occurred in thermoelectric cooling system. Also, the piezoelectric actuator was applied to improve the cooling effect and investigate the heat transfer phenomenon. The temperature distribution of cooling region was measured to investigate cooling characteristics of thermoelectric cooling system. The flow phenomenon of cooling region was visualized using visualization device such as He-Ne laser, optical lens, image grabber and CCD camera. When the piezoelectric actuator was applied to the heat transfer process of thermoelectric cooling system, acoustic streaming was occurred in the cooling region. The acoustic streaming was occurred forced convection flow, and was regularly formed the temperature distribution in the cooling region. In the end, the results clearly show that the acoustic streaming is one of the prime effects to enhance the convection heat transfer and cooling effect.
Authors: Hyun Jae Yoo, Yong Ho Park, Ik Min Park
Abstract: The bulk (Bi0.2iSb0.8)2Te3 thermoelectric alloys added with Ag up to 2.0 mass% were prepared by mechanical alloying and pulse discharge sintering (MA-PDS). Microstructures of the sintered samples were investigated. In the two samples with 1.0 and 2.0 mass% Ag, an abnormal growth of the (Bi,Sb)2Te3 phase, manifested by the formation of coarse crystals that are visible with eye, has been revealed during the PDS process of the alloyed powders. The local temperature rise in the compact induced by the compositional fluctuation as a result of Ag addition was suggested to be responsible for the observed abnormal growth. In addition, the electrical transport properties, i.e., electrical resistivity and Seebeck coefficient, of the sintered samples were studied.
Authors: Pratibha Tiwari, Nishu Gupta, K.M. Gupta
Abstract: Thermoelectric materials are a novel class of materials having unique characteristics. They are Seebeck and Peltier effect materials and are used as thermocouples, for thermoelectric cooling of microelectronic products, as thermoelectric converter for energy conservation etc. Due to their versatility of behaviour, they are now used as construction materials for microelectronic equipment, wireless sensors also. This paper aims at elaborating the development of such materials by compiling the recent and ongoing researches. In this regard, the research developments of some newer materials by other investigators have been presented here. Brief details of the development of thermoelectric generation, thermoelectric cooling, thermoelectric power generator for wearable systems, nano-thermocouple, thermoelectric Peltier microcoolers etc. are presented. In these elaborations, it is shown by the respective investigators that these TE materials can be effectively used in heavily doped semiconductor, thin films, quantum well etc.
Authors: G.A. Suchkova, E.Y. Belyaev, Alexander A. Vlasov, O.I. Lomovsky, Young Soon Kwon
Authors: Ya Jie Liu, Ning Zhu
Abstract: An effective numerical method to predict quantitatively the relation between the dimensionless figure of merit of the state-of-the-art thermoelectric materials with the temperature was investigated by look around for some fitting mathematical functions. The simulative results agree with the observed data very well that the minimum correlation coefficient and the maximum average relative errors between them are 0.9767 and 4.35 % respectively. The high light of this work is that the regular pattern of the dimensionless figure of merit of the state-of-the-art thermoelectric materials dependence temperature appears Gaussian. This conclusion may be an available tip to the the theoretical physicist to build or modify some theoretical model that used to explain the physical mechanisms of the thermoelectric materials.
Authors: Tatsuhiko Aizawa, Kazuto Tokumitsu
Authors: Panida Pilasuta, Pennapa Muthitamongkol, Chanchana Thanachayanont, Tosawat Seetawan
Abstract: Crystal structure of Zn0.96Al0.02Ga0.02O was analyzed by X-Ray diffraction (XRD) technique and the microstructure was observed by scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The XRD results showed single phase and hexagonal structure a = b = 3.24982 Å, and c = 5.20661 Å. The SEM and TEM results showed the grain size of material arrangement changed after sintering and TEM diffraction pattern confirmed hexagonal crystal structure of Zn0.96Al0.02Ga0.02O after sintering.
Authors: Toshiyuki Hirano, J. Teraki, Y. Nishio
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