Processing of nano copper materials for the production of conductive circuits

诸如铜、银和镍的纳米金属的分散体允许使用适当的印刷和固化/烧结工艺来生产导电电路。这种电子电路制造的增材方法允许以最小的浪费和更少的生产步骤制造大面积器件。该技术已应用于许多大面积市场，包括光伏，电磁屏蔽，智能窗户，分布式电源系统和大型电池。用于印刷电路的主要材料是银，但是这具有成本和资源可持续性的限制。铜是地球上丰富的，并有可能显着降低成本，但纳米铜的快速反应性导致氧化，破坏铜的导电性。为了维持导电性，纳米铜必须经历快速（<1 s）受控的纳米颗粒到块体铜的转变。以这种方式，纳米颗粒聚结的动力学比氧化的动力学更快地发生。该项目将研究纳米铜可以以与批量生产兼容的生产速度沉积和烧结的方法。这将利用相关的印刷工艺（喷墨、丝网和静电沉积）和固化设备（激光、NIR、UV和脉冲白色光）。宏观性质变化的实验室研究需要与纳米铜的微观结构和成分变化相关联。该项目最初将针对纳米铜材料，但其他技术，如快速还原氧化铜和分解铜络合物也可能在范围内。在生产电路之后，还可以检查铜电路与其环境之间的相互作用或其与设备中其他材料（如有机导体）的相互作用。1.研究的主要目的/目标。该项目打算回答哪些问题？该项目旨在识别和理解纳米铜油墨烧结过程中发生的物理和化学机制。该项目将解决纳米铜烧结机制与铜颗粒尺寸、温度、能量输入的动力学速率和局部气体环境之间的相互关系。高反应性的铜纳米颗粒经受物理熔化和化学氧化的竞争过程，具有从多孔纳米铜框架到连贯连续的未氧化的金属结构的理想过渡。了解材料和工艺性能对烧结膜的影响是研究的一个关键目标。新的物理科学/工程方法，将在项目过程中进行。学生们会做什么？该项目将通过在热和气体环境（惰性、空气和还原）中烧结选定的材料（粒度分布的变化）来检查烧结工艺的工作范围。将对经受这些烧结环境的印刷样品的导电性、粘附性和接触电阻进行宏观评估。将使用包括AFM、XRD、XPS和SEM在内的分析方法的组合来检查微观尺度上的机制的识别。学生还将研究高速烧结工艺，如近红外，激光和光子烧结，提供潜在的生产力和碳足迹效益。通过迭代研究与方法的细化，这些潜在的有吸引力的过程的潜力将被检查。这项工作将集中在50 x 50 mm的玻璃基板上，以提供热稳定的（在250 C范围内考虑）。3.最后加上一句话，确定研究领域，这将是有帮助的-请从项目材料中选择（材料工程-金属和合金）及其与新制造技术的相互作用，可能的最终用户在

Dispersions of nano-metals such as copper, silver and nickel allow the production of conductive circuitry using an appropriate printing and curing/ sintering process. This additive approach to electronic circuit manufacture allows large area devices to be manufactured with minimal waste and fewer production steps. The technology has applications in a number of large area markets including PV, EM shielding, smart windows, distributed power systems and large batteries. The dominant material for printed circuitry is silver but this has a cost and resource sustainability limitations. Copper is earth abundant and has the potential to significantly reduce cost but the rapid reactivity of the nano-copper leads to oxidation, destroying the conductivity of the copper. In order to sustain conductivity the nano-copper must undergo a rapid (<1s) controlled nano-particle to bulk copper transition. In this way the kinetics of nano particle coalescence occur more rapidly than the kinetics of oxidation. The project will examine means by which nano-copper can be deposited and sintered at production speeds which are compatible with volume manufacturing. This will utilize relevant printing process (inkjet, screen and electrostatic deposition) and curing equipment (laser, NIR, UV and pulsed white light). Laboratory studies of macro changes in properties will need to be correlated to changes in the micro structure and composition of the nano-copper. The project will initially target nano-copper materials, but other technologies such as rapid reduction of copper oxide and decomposition of copper complexes may also be within scope. Having produced circuitry, there is also scope for examining the interaction between the copper circuitry and its environment or its interaction with other materials in a device, such as organic conductors. 1. The key objectives/aims of the research. What questions does the project intend to answer?The project aims to identify and understand the physical and chemical mechanisms which occur during the sintering of nano copper ink. The project will address the inter relationship between the nano copper sintering mechanism and the copper particle size, temperature, kinetic rate of energy input and local gaseous environment. The highly reactive copper nano particles are subject to competing processes physical melting and chemical oxidation, with an ideal transition from a porous nano copper framework to coherent continuous un-oxidized metallic structure. Understanding the impact of material and processing properties on the sintered film is a key objective of the research study.2. The novel physical sciences/engineering methodology that will be carried out during the course of the project. What will the students be doing?The project will examine the working envelope of sintering process, through sintering of a selection of materials (variations in particle size distribution) within thermal and gaseous environments (Inert, air and reducing). Printed samples subjected to these sintering environments will be assessed macroscopically in terms of conductivity, adhesion and contact resistance. Identification of mechanisms on a micro scale will be examined using a combination of analytical methods including AFM, XRD, XPS and SEM. The student will also examine high speed sintering processes such as near infra-red, laser and photonic sintering which offer a potential productivity and carbon footprint benefit. Through iterative studies with refinement of methods, the potential of these potentially attractive processes will be examined. This work will focus on glass substrates of 50 x 50 mm to provide a thermally stable (over the 250C range considered).3. It would be helpful to include a sentence at the end identifying the research area - please select from The project materials lie within (Materials engineering - metals and alloys) and its interaction with novel Manufacturing technologies with a likely end user in the