Rosker Eva S, Barako Michael T, Nguyen Evan, DiMarzio Don, Kisslinger Kim, Duan Dah-Weih, Sandhu Rajinder, Goorsky Mark S, Tice Jesse
NG Next, Northrop Grumman Corporation, 1 Space Park Blvd, Redondo Beach, California 90278, United States.
UCLA Department of Materials Science & Engineering, 420 Westwood Plaza, Los Angeles, California 90095, United States.
ACS Appl Mater Interfaces. 2020 Jul 1;12(26):29684-29691. doi: 10.1021/acsami.0c06959. Epub 2020 Jun 18.
Previous efforts to directly write conductive metals have been narrowly focused on nanoparticle ink suspensions that require aggressive sintering (>200 °C) and result in low-density, small-grained agglomerates with electrical conductivities <25% of bulk metal. Here, we demonstrate aerosol jet printing of a reactive ink solution and characterize high-density (93%) printed silver traces having near-bulk conductivity and grain sizes greater than the electron mean free path, while only requiring a low-temperature (80 °C) treatment. We have developed a predictive electronic transport model which correlates the microstructure to the measured conductivity and identifies a strategy to approach the practical conductivity limit for printed metals. Our analysis of how grain boundaries and tortuosity contribute to electrical resistivity provides insight into the basic materials science that governs how an ink formulator or process developer might approach improving the conductivity. Transmission line measurements validate that electrical properties are preserved up to 20 GHz, which demonstrates the utility of this technique for printed RF components. This work reveals a new method of producing robust printed electronics that retain the advantages of rapid prototyping and three-dimensional fabrication while achieving the performance necessary for success within the aerospace and communications industries.
此前直接书写导电金属的努力主要集中在纳米颗粒墨水悬浮液上，这种悬浮液需要高温烧结（>200°C），并且会形成低密度、小颗粒团聚体，其电导率低于块状金属的25%。在此，我们展示了反应性墨水溶液的气溶胶喷射印刷，并对高密度（93%）印刷的银迹线进行了表征，这些银迹线具有接近块状的电导率，且晶粒尺寸大于电子平均自由程，同时仅需低温（80°C）处理。我们开发了一种预测性电子传输模型，该模型将微观结构与测量的电导率相关联，并确定了一种接近印刷金属实际电导率极限的策略。我们对晶界和曲折度如何影响电阻率的分析，为基础材料科学提供了见解，有助于油墨配方师或工艺开发人员了解如何提高电导率。传输线测量验证了电性能在高达20 GHz时仍能保持，这证明了该技术在印刷射频组件中的实用性。这项工作揭示了一种生产坚固耐用的印刷电子产品的新方法，该方法保留了快速成型和三维制造的优势，同时实现了航空航天和通信行业成功所需的性能。
