基于多尺度纳米银/有机导电墨水的打印电路导电机理研究

The durable development of printing technology, especially the high-resolution electrohydrodynamic (EHD) printing, has made it gradually taking the place of traditional etching process in microelectronics field. The key factor is the research and development of conductive ink in the printing technology. For the most frequently used nano-silver conductive ink, there still exists contradictions between the silver content, ink stability and the conductivity of the printed pattern. Besides, the ink preparation process is always cumbersome and time-consuming. Improvement of the conductivity is urgently need because the very high resistance caused by the tunnels and interfaces between the nanoparticles has suppressed the further application of printing technology. Multi-sized silver nanoparticles will introduced as the conductive component to reduce the tunnel resistance Rt of the printed pattern. Furthermore, conductive organic polymer will applied to reduce the interface resistance Ri. The conductivity is supposed to improved significantly as compared to the mono-sized conductive ink with the same silver content. One-step microwave approach will simplify the process and shorten the fabrication time of the conductive ink. Molecular dynamics simulation work will carry out to reveal the intrinsic reaction process. The promotion mechanism of the multi-size to the printed pattern conductivity, and discovery of the relations between the particle size (morphology), components and conductivity will pave a new way for the conductivity improvement of the printed pattern. The project will not only produce a new kind of conductive ink based on theoretical analysis, but also provide reliable technical support for its practical application in printed electronics.

打印工艺尤其是高分辨率电流体动力学（EHD）打印技术的发展使得其在微电子领域正逐步代替传统的刻蚀工艺，导电墨水的研发是决定其发展速度的关键。最具研究与实用价值的纳米银颗粒墨水存在固含量、稳定性和打印电路导电性三者不可兼顾及制备工艺繁琐的问题，尤其是打印电路导电性亟待提高。本项目拟引入多尺度的纳米银颗粒作为墨水导电组分，减少颗粒间空隙电阻Rt；引入有机导电聚合物，减小颗粒间界面电阻Ri，在相同固含量条件下显著提高打印电路导电性。采用微波一步法实现墨水快速、可控制备，并通过分子动力学模拟揭示微波法制备纳米银导电墨水的微观反应过程。多尺度对于打印电路导电性促进机制的研究，揭示颗粒尺度（形貌）-墨水成分-电路电导率三者之间的内在联系，将为有效提高打印电路导电性提供新思路。本项目不仅在理论分析的基础上制备出新型导电墨水，还为该多尺度纳米颗粒导电墨水的推广应用提供可靠的技术支持。

本项目项目执行期间针对项目的核心研究内容所做的研究工作及取得的研究成果如下：. 微波法制备纳米银颗粒型导电墨水过程中反应条件对产物形貌及图案导电性的影响研究，得到了微波一步法制备多尺度纳米银颗粒型导电墨水的过程中初始银含量、微波反应时间等条件对最终墨水直写图案导电性的影响结果及机理。基于纳米银颗粒与导电聚合物PEDOT:PSS的混合型导电墨水的导电性研究，适量的纳米银颗粒的加入会大大提高导电聚合物的导电性；研究了一种基于微波辅助的微波-离心两步法制备多尺度纳米银颗粒导电墨水的工艺，得到了反应时间对墨水性能的影响及机理。对研发墨水所制备的导电图案的寿命进行检测和相关失效机理研究；研究所制备的墨水在柔性电子器件中的应用效果：初步展开了关于输能天线、射频识别天线和低温气敏传感器的研究。. 本项目所研究一步法或两步法工艺大大降低了墨水制备工艺，实现了墨水快速制备。所研究的多尺度纳米银颗粒导电墨水，将在同等条件下降低墨水中银含量，降低成本，促进银系墨水的广泛应用。