Devan Chinnu V, Kurian Mahima M, P N Santhosh, Varma Manoj Raama, Deb Biswapriya
Centre for Sustainable Energy Technology (C-SET), CSIR-National Institute for Interdisciplinary Science and Technology (NIIST), Thiruvananthapuram- 695019, Kerala, India.
Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India.
Phys Chem Chem Phys. 2024 Jun 12;26(23):16625-16636. doi: 10.1039/d4cp01171f.
In recent times, considerable attention has been given to examining the impact of micro/nanostructure on the thermoelectric characteristics of nonstoichiometric AgSbTe. The present investigation employed direct melting of elements that produced p-type AgSbTe with spontaneous nanostructuring due to cation ordering. The product predominantly features an Ag-deficient AgSbTe phase with monoclinic AgTe nanoprecipitates and exhibits a degenerate semiconductor-like behavior with an energy band gap of 0.15 eV. A Seebeck coefficient of 251 μV K and a power factor of 741 μW m K at near ambient temperature are attained with this composition. The variable range hopping (VRH) and linear magnetoresistance (LMR) confirmed that the low-temperature transport followed a VRH between the localized states. The composition also exhibited glass like thermal conductivity of 0.2 W m K arising from phonon scattering at all-scale hierarchical structures that led to a high of 1.1 at room temperature. The direct melted ingots show a high relative density of ∼97%, Vickers hardness of ∼108.5 kgf mm, and excellent thermal stability, making them an attractive choice for TEGs.
近年来，人们对研究微/纳米结构对非化学计量比AgSbTe热电特性的影响给予了相当多的关注。本研究采用元素直接熔融法，由于阳离子有序排列，制备出具有自发纳米结构的p型AgSbTe。该产物主要特征是具有单斜晶系AgTe纳米沉淀的缺银AgSbTe相，并表现出具有0.15 eV能带隙的简并半导体行为。该成分在接近环境温度时，塞贝克系数为251 μV/K，功率因数为741 μW/(m²K²)。变程跳跃(VRH)和线性磁阻(LMR)证实，低温输运遵循局域态之间的VRH。该成分还表现出类似玻璃的热导率，为0.2 W/(mK)，这是由于在所有尺度的分层结构处声子散射导致室温下具有1.1的高zT值。直接熔铸的锭块显示出约97%的高相对密度、约108.5 kgf/mm²的维氏硬度和优异的热稳定性，使其成为热电器件的有吸引力的选择。
