Tip Directed-Assembly of Nanoparticles via Surface-Plasmon Excitation

这项工作的总体目标是建立尖端定向纳米粒子组装使用表面等离子体激元激发的理论和实验基础。 具体的研究目标包括扩大理解（1）纳米粒子/纳米探针系统的光激发，加热和冷却;（2）纳米粒子的熔化，融合和蒸发;和（3）涉及按比例放大定向纳米组装制造的因素。 该研究方法利用了金属纳米颗粒独特的光学和热学性质。 具体地，某些金属纳米颗粒可以使用在其表面等离子体共振波长下的光激发来选择性地加热。 在这种情况下，在原子力显微镜的控制下，尖锐的纳米级尖端的存在在空间上定位了激发。 最后，纳米颗粒在显著低于其本体熔化温度的温度下熔化，从而允许颗粒熔合成所需结构并最终熔合成活性纳米级器件。 多物理场模拟和基于针尖的组装实验将被用来确定组装过程的最佳分辨率、通量和再现性所需的条件。针尖定向纳米粒子组装的研究将对理解纳米电磁学和热输运产生深远的影响。 这种新的纳米制造技术将产生广泛的社会影响，使生产的有源器件，在计算，通信和医学等领域的应用，从纳米级积木。 此外，这种相对简单和低成本的纳米组装方法将使纳米制造技术更广泛地获得。 为了建立一支训练有素的纳米技术队伍，参与者将在纳米光学，热科学，制造，显微镜，计量学和建模方面接受广泛的跨学科培训。 优秀的本科生参与者将从肯塔基州大学？的纳米工程证书计划（NECP）和纳米技术荣誉计划。 此外，该项目为肯塔基州城市和阿巴拉契亚地区的高中学生提供了纳米技术和光学相关的外展工作的基础。

The overall objective of this effort is to establish the theoretical and experimental foundation for tip-directed nanoparticle assembly using surface-plasmon excitation. Specific research objectives include expanding understanding of (1) optical excitation, heating, and cooling of nanoparticle/nanoprobe systems; (2) melting, fusion, and evaporation of nanoparticles; and (3) factors involved in scaling up directed nano-assembly for manufacturing. The research approach exploits the unique optical and thermal properties of metallic nanoparticles. Specifically, certain metal nanoparticles can be selectively heated using optical excitation at their surface plasmon resonance wavelength. The presence of a sharp, nanoscale tip, under control of an atomic force microscope in this case, spatially localizes the excitation. Finally, nanoparticles melt at temperatures significantly below their bulk melting temperatures allowing fusion of the particles into desired structures and ultimately into active nanoscale devices. Both multi-physics simulations and tip-based assembly experiments will be conducted to determine the conditions required for optimal resolution, throughput, and reproducibility of the assembly process.The investigation of tip directed nanoparticle assembly will have a far reaching impact on the understanding of nanoscale electromagnetics and thermal transport. This new nano-manufacturing technique will have broad societal impact by enabling the production of active devices, with applications in fields such as computing, communications, and medicine, from nanoscale building blocks. In addition, this relatively simple and low-cost nano-assembly approach will make nano-manufacturing technology more widely accessible. In order to establish a highly-trained nanotechnology workforce, participants will receive extensive interdisciplinary training in nanoscale optics, thermal sciences, fabrication, microscopy, metrology, and modeling. Outstanding undergraduate participants will be drawn from the University of Kentucky?s Nanoscale Engineering Certificate Program (NECP) and the Honors Program on Nanotechnology. In addition, the project provides a foundation for nanotechnology and optics related outreach efforts to high schools students in both urban and Appalachian regions of Kentucky.