Laser-based Additive Manufacturing Process Using Water Droplets Carrying Nanoparticles for Microlayer Deposition of Semiconductor Materials on Flexible Substrates

基于激光的增材制造工艺，使用携带纳米粒子的水滴在柔性基板上进行半导体材料的微层沉积

• 批准号: 1563448
• 负责人: Aravinda Kar
• 金额: $ 20万
• 依托单位: The University of Central Florida Board of Trustees
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-01 至 2019-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1563448&HistoricalAwards=false
• 关键词: Laser; based; Additive; Manufacturing; Process

Much research has been carried out to produce nanoparticles of various materials due to excellent mechanical, chemical, electrical, and optical properties of nanoparticles. However, it is difficult to deposit and transform nanoparticles into large two-dimensional and three-dimensional structures, such as thin films and discrete arrays, in a controlled manner. This award supports fundamental research to enable a new additive manufacturing process to deposit nanoparticles into thin films or discrete nanodot arrays (a nanodot is a cluster of nanoparticles). The new process is versatile and scalable, and uses less materials and energy. It can promote roll-to-roll manufacturing of a variety of energy and electronic devices such as conformal solar cells, sensors, and actuators. It can also be used to fabricate masks for nanolithography, nanopillar arrays for photonic crystals, and nanodot arrays for plasmonic surfaces.The new additive manufacturing process involves injecting silicon nanoparticles (contained inside electric field-driven water droplets) into a hollow laser beam. The size of nanoparticles ranges from 5 to 100 nm. The laser beam will heat the droplets, causing the water to evaporate and the nanoparticles to sinter and form microlayers on flexible substrates such as polyimide plastic (Kapton) or stainless steel foil. For this process to work, the laser beam needs to be focused so that its diameter is smaller than its wavelength. The droplet will serve as both a nanoparticle carrier, and a superlens that focuses a laser beam to subwavelength diameters. The dropsize has to be within an upper and lower critical limit. The first research objective is to determine these limits, and will be achieved through laser beam propagation modeling and droplet deposition experiments. The model involves numerical solution of Maxwell equations, and the solution yields the two limits. Several dropsizes will be chosen within these limits to conduct experiments. The size and feed rate of droplets will be measured using high speed photography; particle concentration using colloidal testing meter; the laser power, diameter, and pulse repetition rate using laser beam analyzer; the speed and temperature of substrate using substrate feed controller and thermography respectively. The grain size of the microlayer (determined by process variables) affects the electrical conductivity of the microlayer. The second research objective is to establish the relationship between the grain size and conductivity. It will be achieved by measuring the grain size using atomic force microscopy and scanning electron microscopy, and the conductivity using four-probe technique.

由于纳米颗粒具有优异的机械、化学、电学和光学性能，已经进行了大量研究以生产各种材料的纳米颗粒。 然而，很难以受控的方式将纳米颗粒存款并转化成大的二维和三维结构，例如薄膜和离散阵列。 该奖项支持基础研究，使新的增材制造工艺能够将纳米颗粒存款到薄膜或离散的纳米点阵列中（纳米点是纳米颗粒的簇）。新工艺具有通用性和可扩展性，并且使用更少的材料和能源。 它可以促进各种能源和电子设备的卷对卷制造，如保形太阳能电池，传感器和致动器。 它还可以用于制造纳米光刻的掩模，光子晶体的纳米柱阵列和等离子体表面的纳米点阵列。新的增材制造工艺包括将硅纳米颗粒（包含在电场驱动的水滴中）注入中空激光束。纳米颗粒的尺寸范围为5至100 nm。激光束将加热液滴，使水蒸发，纳米颗粒烧结并在聚酰亚胺塑料（Kapton）或不锈钢箔等柔性基底上形成微层。为了使这一过程发挥作用，激光束需要聚焦，使其直径小于其波长。液滴将作为纳米颗粒载体和将激光束聚焦到亚波长直径的超透镜。液滴大小必须在临界上限和临界下限之内。第一个研究目标是确定这些限制，并将通过激光束传播建模和液滴沉积实验来实现。该模型涉及到麦克斯韦方程的数值解，解产生两个极限。将在这些限制范围内选择几个液滴大小进行实验。将使用高速摄影测量液滴的尺寸和进给速率;使用胶体测试仪测量颗粒浓度;使用激光束分析仪测量激光功率、直径和脉冲重复率;分别使用基板进给控制器和热成像仪测量基板的速度和温度。微层的晶粒尺寸（由工艺变量确定）影响微层的电导率。第二个研究目标是建立晶粒尺寸和电导率之间的关系。它将通过使用原子力显微镜和扫描电子显微镜测量晶粒尺寸，并使用四探针技术测量电导率来实现。