NER: Directed and Selective Self-Assembly of Nanosized Particles via Surface-Plasmon Excitation

了解和实现金属纳米粒子的主动定向组装对纳米技术的未来至关重要。纳米金属颗粒具有独特的光学和电子特性，这使它们成为生物化学传感、通信、医学和电子领域应用的理想基石。本研究利用金属纳米结构独特的光学和热特性，选择性地将其组装成有源纳米器件。这代表了迈向通用纳米组装技术的第一步，同时也探索了纳米电磁学和热力学的基本问题。作为他们的主要目标，研究人员正在开发一种方法，利用原子力显微镜探针和表面等离子激元激发，选择性地和局部地将纳米级粒子融合成相干结构。金属纳米颗粒的表面在明显低于体熔化温度的温度下熔化，并允许在光激发下进行粒子融合。表面等离子体共振的性质允许粒子根据尺寸、材料和局部微观环境被选择性地激发，为在同一时间框架内组装多种材料的集成过程打开了大门。纳米粒子-纳米探针系统的研究将对纳米尺度的电磁学和热力学的理解产生深远的影响。此外，一种新的纳米级组装技术的框架将使新的有源纳米器件成为可能，并使纳米组装技术更广泛地应用。该项目吸引了肯塔基大学两个纳米技术项目的学生和研究人员：纳米工程证书项目（NECP）和纳米技术伞项目（UPoN）。此外，参与这项研究工作的学生还将接受电气、机械、生物系统和农业工程研究人员的跨学科培训。

Understanding and implementation of active, directed assembly of metallic nanoparticles is crucial for the future of nanotechnology. Nanosized metallic particles have unique optical and electronic properties that make them highly desirable building blocks for applications in bio-chemical sensing, communications, medicine, and electronics. This research effort exploits the unique optical and thermal properties of metallic nanostructures to selectively direct their assembly into active nanodevices. This represents the first step toward a general-purpose nanoassembly technology while also exploring fundamental issues in nanoscale electromagnetics and thermodynamics. As their principle aim, the investigators are developing a method to selectively and locally fuse nanoscale particles into coherent structures using an atomic force microscopy probe and surface-plasmon excitation. The surfaces of metallic nanoparticles melt at temperatures dramatically lower than the bulk melting temperature and permit particle fusion using optical excitation. The nature of the surface plasmon resonances allows the particles to be selectively excited based on size, material, and local microscopic environment, opening the door for an integrated process that permits multiple materials to be assembled during the same time frame. The investigation of nanoparticle-nanoprobe systems will have a far reaching impact on the understanding of nanoscale electromagnetics and thermodynamics. In addition, a framework for a new nanoscale assembly technique will enable new active nanodevices and make nanoassembly technology more widely available. The project draws students and researchers from the University of Kentuckys two Nanotechnology Programs: the Nanoscale Engineering Certificate Program (NECP) and the Umbrella Program for Nanotechnology (UPoN). In addition, the students involved in this research effort receive interdisciplinary training with investigators in Electrical, Mechanical, and Biosystems and Agricultural Engineering.