Sintering of silver nanoparticle structures and the pursuit of minimum resistivity

Abstract

Over the past two decades, metal nanoparticles have been extensively studied in the field of printed electronics. In particular, highly conductive metal nanoparticles (NPs) such as silver, copper, and gold in the form of inks have been thoroughly investigated as potential candidates for the fabrication of conductive tracks via printing technologies. The metal NP inks are printed into the desired patterns and sintered through various methods to reduce the resistivity close to their bulk counterparts. Closing the gap between the metal NPs and their bulk counterpart's resistivity has been challenging. The challenges lie in the complex behavior of metal nanoparticles due to their size reduction, the NP ink composition, the substrate compatibility, and numerous other technical domains which are the spotlight of our discussion. Moreover, to meet the demands of rapid manufacturing, several optimizations are required in the applied sintering techniques. In this study, we explore the challenges involved, the strengths, and the shortcomings of several thermal sintering methods investigated so far over the past 20 years or so, while focusing on the acquired minimum metal NPs resistivity in each method.