Sub-nanomaterials possess unprecedented size-dependent properties compared to conventional nanomaterials, which endow them with great potential in catalysis, biomedicine, sensors, and so on. However, their applications in thermoelectrics are unknown due to poor thermal stability and low yields. Herein, we construct a series of thermoelectric composites by incorporating highly thermally stable and commercial fullerene sub-nanoclusters (C60 or C70). We find that sub-nanoclusters as the second phase can conduce to optimized carrier concentration through charge transfer at interfaces while the carrier mobility is significantly enhanced due to atom orbital hybridization and size-dependent electrical scattering mechanism. Furthermore, the ultra-low thermal conductivity of C60 due to its distorted chemical bonding and sub-nanometer pore, and the interfacial thermal resistance greatly suppress the phonon transport. Consequently, the 0.15 mol.% C60/Bi0.4Sb1.6Te3 realizes an ultra-high ZT of ∼1.6 at 373 K, an excellent thermoelectric conversion efficiency of ∼7.4 %, and a huge cooling performance of ∼73 K. This work demonstrates the application of sub-nanomaterials in thermoelectrics and may shed light on other fields such as electronic devices, thermal management, and fullerene chemistry.

中文翻译：

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通过掺入均匀分散的富勒烯亚纳米团簇构建高性能体热电复合材料


与传统纳米材料相比，亚纳米材料具有前所未有的尺寸依赖性特性，这使它们在催化、生物医学、传感器等方面具有巨大潜力。然而，由于热稳定性差和产量低，它们在热电中的应用尚不清楚。在此，我们通过结合高热稳定性和商用富勒烯亚纳米团簇（C60 或 C70）构建了一系列热电复合材料。我们发现，作为第二相的亚纳米团簇可以通过界面处的电荷转移来优化载流子浓度，同时由于原子轨道杂化和尺寸依赖性的电散射机制，载流子迁移率得到显着增强。此外，C60 由于其扭曲的化学键和亚纳米孔隙而具有超低的热导率，以及界面热阻，极大地抑制了声子传输。因此，0.15 mol.% C60/Bi0.4Sb1.6Te3 在 373 K 时实现了 ∼1.6 的超高 ZT、∼7.4 % 的出色热电转换效率和 ∼73 K 的巨大冷却性能。这项工作展示了亚纳米材料在热电学中的应用，并可能为电子设备、热管理和富勒烯化学等其他领域提供启示。