Hu Qiujun, Qiu Wenbin, Chen Longqing, Chen Jie, Yang Lei, Tang Jun
College of Physics, Sichuan University, Chengdu 610065, China.
Key Laboratory of Radiation Physics and Technology of Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, China.
ACS Appl Mater Interfaces. 2021 Aug 18;13(32):38526-38533. doi: 10.1021/acsami.1c12722. Epub 2021 Aug 4.
Due to the excellent thermoelectric performance, bismuth telluride (BiTe) compounds are highly promising for the thermoelectric conversion in the room temperature range. However, the inferior thermoelectric performance of the n-type leg severely restricts the applications of BiTe-based thermoelectric couples. Herein, n-type BiTeSe (BTS)-based thermoelectric materials incorporated with nanosized YO (0.5-3 wt %) are prepared and their thermoelectric properties are systematically studied. The dramatically improved thermoelectric performance is ascribed to the realization of a multiscale feature of YO nanoparticle (NP)-induced interfacial decorations distributed along grain boundaries, which creates massive BTS/YO interfaces for the manipulation of carrier and phonon transport properties. The geometric phase analysis is employed to further confirm the condition of local strain in the BTS composite incorporated with YO NPs. Due to the presence of heterointerfaces and high density of dislocations in BTS matrices, the minimum lattice thermal conductivity (κ) of the nanocomposites (NCs) is dramatically suppressed from 0.76 to 0.37 W m K. With the incorporation of 3 wt % YO NPs, the Vickers hardness of the BTS/YO NC is increased by about 32%. Overall, the BTS + 1.5 wt % YO NC maintains excellent thermoelectric properties (ZT = 1.1) in the whole operative temperature range (300-500 K). The present strategy of implementing high-density heterogeneous interfaces by YO NP addition offers an applicable pathway for fabricating high-performance thermoelectric materials with both optimized thermoelectric properties and mechanical properties.
由于具有优异的热电性能，碲化铋（BiTe）化合物在室温范围内进行热电转换方面极具潜力。然而，n型支路较差的热电性能严重限制了基于BiTe的热电偶的应用。在此，制备了掺入纳米尺寸YO（0.5 - 3 wt%）的n型BiTeSe（BTS）基热电材料，并对其热电性能进行了系统研究。热电性能的显著提升归因于实现了沿晶界分布的YO纳米颗粒（NP）诱导的界面修饰的多尺度特征，这为操控载流子和声子输运特性创造了大量的BTS/YO界面。采用几何相分析进一步确认了掺入YO NPs的BTS复合材料中的局部应变情况。由于BTS基体中存在异质界面和高密度位错，纳米复合材料（NCs）的最小晶格热导率（κ）从0.76大幅降至0.37 W m⁻¹ K⁻¹。掺入3 wt%的YO NPs后，BTS/YO NC的维氏硬度提高了约32%。总体而言，BTS + 1.5 wt% YO NC在整个工作温度范围（300 - 500 K）内保持优异的热电性能（ZT = 1.1）。通过添加YO NPs实现高密度异质界面的当前策略为制备具有优化热电性能和机械性能的高性能热电材料提供了一条可行途径。
