Sintering Kinetics of Inkjet-Printed Conductive Silver Lines on Insulating Plastic Substrate

This paper focuses on sintering kinetics of inkjet-printed lines containing silver nanoparticles deposited on a plastic substrate. Upon heat treatment, the change of resistance in the printed lines was measured as a function of time and sintering temperatures from 423 K to 473 K (150 °C to 200 °C). A new phenomenon was observed that a critical temperature existed for the sintering process, beyond which there was no further reduction in resistance. Experimental evidence and analysis show the critical temperature is associated with the boiling point of the solvent. New sintering mechanisms have been proposed to explain the observed phenomenon, including accelerated diffusion facilitated by the existence of liquid solution based on the theory of liquid phase sintering, and particle collision and coalescence caused by the induced liquid flows in the solution. The proposed theory suggest new means can be devised to improve the sintering results for inkjet-printed lines and other applications.