Additive Manufacturing and Laser Processing of Conductive Nanomaterial - Fundamentals and Applications

Printable electronics have been developing rapidly in recent decades. Various printing technologies, such as aerosol jet, inkjet, and screen printing, have been developed, and some of these technologies are already being applied to the industrial fabrication process. Along with the development of printing methods, a number of materials have been studied for more advanced electrode devices and component fabrication, such as sensors, transistors, and radiofrequency devices. However, compared with conventional clean room technologies, such as photolithography and thin film deposition process, printing is still limited in resolution. For today’s printing technology, the printing resolution is around 1-10 µm, which is significantly larger than a typical cleanroom fabrication limitation of 0.2 µm. We propose that using a laser as a precise tool is a very attractive method for shrinking this technical gap. In the dissertation research, we combined both laser processing methods and printing methods to attempt to develop a novel fabrication process for printable electrode devises. In chapter 2, the extrusion printing method and laser sintering processes were applied. A 3D printed Al anode was fabricated for an Al-Air battery. By applying the laser sintering process, the battery performance significantly improved. In chapter 3, a flexible current sensor was fabricated by Aerosol jet printing. Additionally, a CO2 laser was used to create a structed cutting path during the fabrication process. In chapter 4, a laser with a graphene sensor array was developed for multi-target sensing. An FS laser was used for the laser direct writing process. The sensor system has a nice sensitivity and selectivity for multiple targets. In chapter 5 and chapter 6, the effects of laser irradiation for 1D nanomaterials were studied, and related applications were developed. Through these studies, we provide evidence for our hypotheses: proper laser processing can improve the performance of printed electrical devices, especially in reducing contact resistance, changing nanomaterial structure, and improving fabrication precision.