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Thermoelectric effects at the nanoscale

纳米尺度的热电效应

基本信息

批准号：
242631004
负责人：
Professor Dr. Frank Cichos
金额：
--
依托单位：
Peter-Debye-Institut für Physik der weichen Materie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2013
资助国家：
德国
起止时间：
2012-12-31 至 2018-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/242631004?language=en
关键词：
Thermoelectric effects nanoscale

项目摘要

In recent years it has become clear that the thermal forces on charged colloids are to a large extent determined by thermoelectricity. In the bulk, the thermoelectric or Seebeck field is proportional to the applied temperature gradient. Both sign and magnitude of the Seebeck coefficient depend on the electrolyte composition and the connected effects explain a wealth of current experiments on colloidal suspensions. The perspectives of the thermoelectric effects in solution are, however, much wider than currently explored.Thermoelectric effects are, for example, highly relevant for biotechnological and microfluidic applications, where selective colloidal transport, size separation, molecular trapping and confinement are required. Such applications become even more appealing when considering that the required heating for such thermoelectric processes can be supplied by taking advantage of the strong plasmonic interaction of noble metal structures with light. This leads to very strong local temperature gradients, which will allow for a new type of optically controlled micro- and nanofluidics in future applications. This project thus proposes to explore in a unique combined theoretical and experimental effort, the thermoelectric properties at the nano- and micro-scale in an electrolyte solution. There are two main objectives: The first one is to better understand the forces operating in the self-propulsion of hot Janus particles. The second one aims at the design and realization of thermally generated electric fields in confined geometries and nanostructures. On the theoretical side we have to solve the coupled thermo-electro-osmotic equations relating the salt-ion currents and the Seebeck field. Then the particle motility is obtained from plugging the resulting thermodynamic forces in the Stokes equation. As main results we expect to determine the charge distribution in the vicinity of a hot particle, in particular the net thermo-charge and the dipole moment, and the resulting translational and rotational motion. We intend to work out possible microfluidic applications for colloidal transport and separation by size.The experiments proposed in this project are directly related to the theoretical tasks. They focus on the study of the influence of thermoelectric effects on the motion of noble metal and noble metal capped Janus particles, which are heated by optical means. The experiments involve advanced particle tracking techniques, which are combined with active particle manipulation, such as the recently developed photon nudging. The experimental studies will be completed by an investigation of the electric field distribution around mobile and immobile heated metal nanostructures in electrolyte solution, which will provide the fundamental means to develop new structures for the generation of freely configurable thermoelectric fields for micro- and nano-manipulation.

近年来已经很清楚，带电胶体上的热作用力在很大程度上是由热电决定的。在体中，热电场或塞贝克场与施加的温度梯度成正比。塞贝克系数的符号和大小都取决于电解质的组成，相关效应解释了当前大量关于胶体悬浮液的实验。然而，溶液中热电效应的前景比目前探索的要广泛得多。例如，热电效应与生物技术和微流体应用高度相关，其中需要选择性胶体运输，大小分离，分子捕获和限制。当考虑到这种热电过程所需的加热可以通过利用贵金属结构与光的强等离子体相互作用来提供时，这种应用变得更加吸引人。这导致了非常强的局部温度梯度，这将允许一种新型的光控微纳米流体在未来的应用。因此，本项目提出以一种独特的理论和实验相结合的方式，探索电解质溶液中纳米和微尺度的热电特性。有两个主要目标：第一个是更好地理解热Janus粒子自我推进的力。第二部分是在受限几何和纳米结构中热致电场的设计和实现。在理论方面，我们必须求解有关盐离子电流和塞贝克场的耦合热-电渗透方程。然后将得到的热力学力代入Stokes方程，得到粒子的运动特性。作为主要结果，我们期望确定热粒子附近的电荷分布，特别是净热电荷和偶极矩，以及由此产生的平移和旋转运动。我们打算研究微流体在胶体运输和粒径分离方面的可能应用。本课题提出的实验与理论任务直接相关。他们着重研究了热电效应对用光学方法加热的贵金属和贵金属包覆的Janus粒子运动的影响。实验涉及先进的粒子跟踪技术，它与主动粒子操作相结合，例如最近开发的光子轻推。实验研究将通过对电解质溶液中可移动和不可移动加热金属纳米结构周围电场分布的研究来完成，这将为开发用于微纳米操作的可自由配置热电场的新结构提供基础手段。