Peltier cooling in molecular junctions
Peltier cooling in molecular junctions
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DOI：
10.1038/s41565-017-0020-z
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发表时间：
2018-02-01
影响因子：
38.3
通讯作者：
Reddy, Pramod
中科院分区：
文献类型：
--
作者：
Cui, Longji;Miao, Ruijiao;Reddy, Pramod
分子结中热电性的研究对于包括冷却（制冷）和热电转换（1-4）在内的各种技术的发展具有根本意义。最近在探测分子结（5-9）的热电势（塞贝克效应）方面的实验进展使得能够研究热电性和分子结构之间的关系（10，11）。然而，珀耳帖冷却在分子结的观察-建立基于分子的制冷的关键步骤-仍然无法访问。在这里，我们报告直接的实验观察分子结的珀耳帖冷却。通过将导电探针原子力显微镜（12，13）与定制的皮瓦分辨率量热微器件相结合，我们创建了一个实验平台，可以统一表征分子结的电学，热电和能量耗散特性。利用该平台，我们研究了金与典型分子（Au-联苯-4，4 '-二硫醇-Au，Au-三联苯-4，4“-二硫醇-Au和Au-4，4'-联吡啶-Au）的结，揭示了加热或冷却与电荷传输特性的关系。我们的实验结论得到了自能校正的密度泛函理论计算的支持。我们希望这些进展能够刺激分子结中的热传输和热电传输的研究，在分子结中，理论上已经预测了非常有效的能量转换的可能性（2- 4，14）。
The study of thermoelectricity in molecular junctions is of fundamental interest for the development of various technologies including cooling (refrigeration) and heat-to-electricity conversion(1-4). Recent experimental progress in probing the thermopower (Seebeck effect) of molecular junctions(5-9) has enabled studies of the relationship between thermoelectricity and molecular structure(10,11). However, observations of Peltier cooling in molecular junctions-a critical step for establishing molecular-based refrigeration-have remained inaccessible. Here, we report direct experimental observations of Peltier cooling in molecular junctions. By integrating conducting-probe atomic force microscopy(12,13) with custom-fabricated picowatt-resolution calorimetric microdevices, we created an experimental platform that enables the unified characterization of electrical, thermoelectric and energy dissipation characteristics of molecular junctions. Using this platform, we studied gold junctions with prototypical molecules (Au-biphenyl-4,4'-dithiol-Au, Au-terphenyl-4,4 ''-dithiol-Au and Au-4,4'-bipyridine-Au) and revealed the relationship between heating or cooling and charge transmission characteristics. Our experimental conclusions are supported by self-energy-corrected density functional theory calculations. We expect these advances to stimulate studies of both thermal and thermoelectric transport in molecular junctions where the possibility of extraordinarily efficient energy conversion has been theoretically predicted(2-4,14).