Hybrid manipulation of inkjet-printing deposition pattern of high particle concentration droplet by means of thermal and binary solvent effects

Abstract

Inkjet-printing of functional material is a well-known drop-on-demand technology used in a wide range of modern applications, such as flexible electronics, biomedical testing, etc. It enables to deliver small amount of materials as ink to the specific location on target substrates. However, it is challenging to precisely manipulate the particle deposition characteristics which is crucial to the quality of the fabricated device. Unlike the traditional passive methods by manipulating the nanoparticle, solvent or substrate surface condition, we propose a passive-active hybrid manipulation method by employing a binary mixture solvent and heating substrate. In this paper, the effects of the solvent mixing ratio, the substrate temperature, the substrate thermal properties on the deposition characteristics of high concentration ITO nano-ink were investigated. Interestingly, we have observed a transition of the classic slim coffee-ring to a fat coffee-ring with a large ring width. A dimensionless number was developed to predict the transition boundary from fat-ring pattern to slim-ring pattern. Finally, the phase diagrams of deposition patterns on three substrates were developed, which were convenient for deposition pattern manipulation in real applications.