Bi2(Te,Se)3 alloys are conventional commercial thermoelectric materials for solid-state refrigeration around room temperature. In recent years, much attention has been paid to various advanced thermoelectric composite materials due to the unique thermoelectric properties. In this work, Bi2Se3/TiO2 composites were prepared by hot pressing the plate-like Bi2Se3 powders coated in situ with hydrolyzed hytetabutyl-n-butyl titanate (TNBT), and therefore numerous TiO2 in micrometer size could be formed on the interface of Bi2Se3 grains. The carrier concentration in Bi2Se3 matrix is optimized subject to the addition of n-type semiconductor TiO2, contributing to a significant improved power factor. In the meantime, the lattice thermal conductivity is also suppressed due to the enhanced phonon scattering at Bi2Se3/TiO2 interface and amorphous TiO2 particles. As a consequence, a peak figure of merit (zT) of 0.41 is obtained at 525 K in Bi2Se3/15 mol% TiO2 composites, nearly 50% augment over the pristine Bi2Se3 binary compound.

中文翻译：

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Bi2Se3/TiO2复合材料的热电性能增强

Bi2(Te,Se)3 合金是用于室温左右固态制冷的常规商业热电材料。近年来，各种先进的热电复合材料由于其独特的热电性能而备受关注。在这项工作中，Bi2Se3/TiO2 复合材料通过热压原位涂有水解钛酸正丁酯 (TNBT) 的片状 Bi2Se3 粉末来制备，因此可以在 Bi2Se3 晶粒界面上形成大量微米级的 TiO2。 . 通过添加 n 型半导体 TiO2，优化 Bi2Se3 基体中的载流子浓度，从而显着提高功率因数。同时，由于 Bi2Se3/TiO2 界面和非晶 TiO2 颗粒处的声子散射增强，晶格热导率也受到抑制。