One-dimensional tellurides Ta4SiTe4 and Nb4SiTe4 were found to show high thermoelectric performance below room temperature. This study reported the synthesis and thermoelectric properties of whisker crystals of Ta4SiTe4-Nb4SiTe4 solid solutions and Mo- or Ti-doped (Ta0.5Nb0.5)4SiTe4. Thermoelectric power of the solid solutions systematically increased with increasing Ta content, while their electrical resistivity was unexpectedly small. Mo- and Ti-doped (Ta0.5Nb0.5)4SiTe4 showed n- and p-type thermoelectric properties with large power factors exceeding 40 microW cm-1 K-2, respectively. The fact that not only Ta4SiTe4 and Nb4SiTe4 but also their solid solutions showed high performance indicated that this system is a promising candidate for thermoelectric applications at low temperatures.
Anharmonic phonon effects on linear thermal expansion of trigonal bismuth selenide and antimony telluride crystals
采用并扩展了一种有效的Grüneisen方法,研究了三方结构硒化铋(Bi $_2$ Se $_3$)和碲化锑(Sb $_2$ Te $_3$)的声子非谐性和线性热膨胀系数(TEC).系统的非谐性进行了研究,通过广泛的计算Grüneisen参数,利用保序变形。与实验结果相一致,在$a$和$c$方向的TEC之间存在较大的各向异性。Sb $_2$ Te $_3$中固有的较大非谐性与Bi $_2$ Se $_3$相比被体积效应抵消,导致它们的线性TEC具有可比的温度依赖性。从我们的第一性原理数据推导出的德拜温度也非常符合现有的表中的值。这项工作中开发的高效方法首次应用于研究两个三角形热电系统的线性TEC,为解决其他热电和其他低对称性材料中的非谐效应提供了令人兴奋的机会。
Hole-Doped M4SiTe4 (M = Ta, Nb) as an Efficient p-Type Thermoelectric Material for Low-Temperature Applications
固态热电制冷有望广泛应用于各种低温应用,如超导器件的局部冷却。然而,目前,使用p型和n型Bi 2 Te 3基材料的热电冷却仅在室温下投入实际使用。最近发现M_4SiTe_4(M = Ta,Nb)在低至50 K的温度范围内显示出优异的n型热电性能。本文报道了通过Ti掺杂合成高性能p型M4 SiTe 4,其可以在低温冷却装置中与n型M4 SiTe 4相结合。p型M4 SiTe 4的热电功率因子在210 K时达到最大值约60 uW cm-1 K-2,在130-270 K的较宽温度范围内超过了实际水平。在由p型和n型Ta_4SiTe_4晶须晶体制成的冷却装置中也实现了通过Peltier冷却的有限温度下降。这些结果清楚地表明,M4 SiTe 4是有希望实现一个实用的热电冷却器,在低温下使用,这是没有覆盖的Bi 2 Te 3基材料。
Germanium telluride (GeTe), a phase-change material, is known to exhibit four different structural phases: three at room temperature (one amorphous and two crystalline, $α$ and $γ$) and one at high temperature (crystalline $β$). Because transitions between the amorphous and crystalline phases lead to significant changes in material properties (e.g., refractive index and resistivity), GeTe has been investigated as a phase-change material for photonics, thermoelectrics, ferroelectrics, and spintronics. Consequently, the temperature-dependent phase transitions in GeTe have been studied for bulk a…
The optimization of secondary phase in thermoelectric(TE) materials can {helps in improvisation of material's efficiency}. Being a potential {contender} for lower temperature TE application, bismuth telluride(Bi$_2$Te$_3$) nanoparticles were synthesized via different routes and profiles to optimize their pure single phase. Systematic characterizations were performed with the help of X-ray diffraction (XRD), Rietveld refinement and field effect-scanning electron microscopy(FE-SEM) for structural and morphological behavior, while TE properties such as Seebeck coefficient, electrical conductivity…
Predicting the Realizable Maximum Power Factor using the Jonker and Ioffe formulation: Al-doped ZnO Triangular Microcrystals with Graphite Inclusion Case Study