Jiang Zhongsheng, Ming Hongwei, Qin Xiaoying, Feng Dan, Zhang Jian, Song Chunjun, Li Di, Xin Hongxing, Li Juncai, He Jiaqing
Key Lab of Photovoltaic and Energy Conservation Materials, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China.
University of Science and Technology of China, Hefei 230026, China.
ACS Appl Mater Interfaces. 2020 Oct 14;12(41):46181-46189. doi: 10.1021/acsami.0c13542. Epub 2020 Sep 30.
To achieve high thermoelectric conversion efficiency in BiSbTe (BST) alloy is vital for its applications in low-grade energy harvesting. Here, we show that 56% increase in the power factor (PF) (from 16 to 25 μW cm K) and 32% reduction of lattice thermal conductivity κ (from 0.56 to 0.38 W m K) as well as an approximately four-fold decrease in bipolar-effect contribution κ (from 0.48 to 0.12 W m K) can be achieved at 512 K through the incorporation of 0.2 vol % PbSe nanoparticles in the BST matrix. Analyses indicate that the remarkable increase in PF for the composite samples can be mainly attributed to strong electron scattering at the large interface barriers, inhibiting effectively the electron contribution to the total thermopower at elevated temperatures, while the large drop of κ and κ originates from enhanced phonon scattering by PbSe nanoinclusions as well as phase boundaries (among BST and PbSe nanophase) and suppression of electron transport, respectively. As a result, a maximum figure of merit (ZT) of 1.56 (at 400 K) and an average ZT (ZT) of 1.44 in the temperature range of 300-512 K are reached. Correspondingly, a record projected conversion efficiency η = 11% is achieved at the cold side 300 K and hot side 512 K in the BST-based composite incorporated with 0.2 vol % PbSe nanoinclusions.
在BiSbTe（BST）合金中实现高热电转换效率对其在低品位能量收集方面的应用至关重要。在此，我们表明，通过在BST基体中掺入0.2体积%的PbSe纳米颗粒，在512 K时功率因子（PF）可提高56%（从16 μW cm⁻¹ K⁻²提高到25 μW cm⁻¹ K⁻²），晶格热导率κ降低32%（从0.56 W m⁻¹ K⁻¹降低到0.38 W m⁻¹ K⁻¹），双极效应贡献κ降低约四倍（从0.48 W m⁻¹ K⁻¹降低到0.12 W m⁻¹ K⁻¹）。分析表明，复合样品PF的显著提高主要归因于大界面势垒处的强电子散射，有效抑制了高温下电子对总热功率的贡献，而κ和κ的大幅下降分别源于PbSe纳米夹杂以及相界（BST和PbSe纳米相之间）增强的声子散射和电子输运的抑制。结果，在400 K时达到了1.56的最大优值（ZT）以及在300 - 512 K温度范围内1.44的平均ZT（ZT）。相应地，在掺入0.2体积% PbSe纳米夹杂的基于BST的复合材料中，在冷端300 K和热端512 K时实现了创纪录的预计转换效率η = 11%。
