Continuous, Large-scale Manufacturing of Functionalized Silver Nanowire Transparent Conducting Films

本研究旨在探索一种新的技术，用于纳米物联网的银纳米线透明导电膜的经济制造。 纳米物联网有望将新一代传感器、传感器、数据处理器和通信设备连接起来，实现智能互联的世界。 所有纳米器件的一个重要组成部分是透明导电膜，通常由银纳米线制成。 当前银纳米线的制造是昂贵的，因为其涉及多步批量生产。 该奖项研究了一种大规模制造银纳米线的新方法，该方法与用于图案化透明导电膜的三维印刷系统直接耦合。 透明导电膜和按需印刷银纳米线的成本降低，加速了纳米物联网设备的采用，这有助于美国的经济和繁荣。 这项研究结合了制造，材料科学，纳米技术，化学和工程等方面。 学生积极参与研究，从而获得先进制造业的工程专业知识，这对美国工业很重要。 本项目通过研究连续反应器的反应条件和反应机理，在柔性基板上连续印刷银纳米线（AgNW）导电油墨，制作用于纳米物联网（IoNT）的透明导电膜（TCF）。 目前AgNW的批量生产涉及选择性分离和浓缩所需AgNW的昂贵步骤。 此外，AgNW在恶劣环境中易于氧化。本项目研究了一种用于制造单分散AgNW的毫流系统，该系统具有可控的长度和纵横比以及足够的高性能TCF浓度。 毫流反应器连接到3D打印机，用于连续制造和打印AgNW基TCF，降低成本，同时保持高打印质量。 通过X射线吸收光谱法原位监测毫流体合成提供了对反应机制的基本理解。 化学反应的机理知识有助于实现对AgNW的纵横比和产率的控制。 使用Pd纳米粒子通过用Pd阳离子电置换Ag来改性AgNW以实现抗氧化的稳定性。这项研究提出了AgNW TCF，其成本低，环境稳定，该项目由先进制造计划和刺激竞争力研究既定计划（EPSCoR）共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This research aims to discover a new technique for the economical manufacture of silver nanowire transparent conductive films for the Internet of Nano Things. The Internet of Nano Things promises to connect a new generation of sensors, transducers, data processors and communication devices for a smart and connected world. A vital component of all nanodevices is transparent conductive films, generally made of silver nanowires. Current manufacture of silver nanowires is costly as it involves multi-step batch production. This award investigates a new approach for large-scale manufacture of silver nanowires with direct coupling with a three-dimensional printing system for patterning of transparent conducting films. The reduced cost of transparent conducting films and print-on-demand silver nanowires hasten the adoption of devices for the Internet of Nano Things, which contributes to the U.S. economy and prosperity. This research combines aspects of manufacturing, material science, nanotechnology, chemistry, and engineering. Students actively participate in research thus achieving engineering expertise in advanced manufacturing, which is important to U.S. industry. Undergraduate and graduate students, particularly from under-represented groups, are encouraged to participate in research and training.This project studies the reaction conditions and mechanisms in a continuous reactor to produce silver nanowire (AgNW)-based conductive inks that can be continuously printed onto flexible substrates to create transparent conducting films (TCFs) for the Internet of Nano Things (IoNT). The current batch production of AgNWs involves the costly steps of selective separation and concentration of the desired AgNWs. In addition, AgNWs are prone to oxidation in harsh environments. This project studies a millifluidic system for the manufacture of monodispersed AgNWs with controllable length and aspect ratio and sufficient concentration for high performance TCFs. The millifluidic reactor is connected to a 3D printer for continuous manufacture and printing of AgNW-based TCFs with a reduction in cost while maintaining high print quality. In-situ monitoring of the millifluidic synthesis by X-ray absorption spectroscopy provides fundamental understanding of the reaction mechanisms. Mechanistic knowledge of the chemical reactions helps to achieve control over the aspect ratio and yield of the AgNWs. The AgNWs are modified using Pd nanoparticles via the galvanic replacement of Ag with Pd cations to achieve stability against oxidation. This research advances AgNW TCFs that are low cost, environmentally stable, with flexible/stretchable characteristics needed in applications such as IoNT devices with high potential for advancing the field of flexible electronics.This project is jointly funded by the Advanced Manufacturing Program and the Established Program to Stimulate Competitive Research (EPSCoR).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.