Evolution of Nanoparticle Deposits Printed Using Electrospray

Abstract

In an electrospray, large electric potentials are used to generate a spray of highly charged droplets. Colloidal dispersions, consisting of nanoparticles in a volatile solvent, can be atomized using electrospray. Printing occurs by directing the emitted droplets toward a target substrate (TS). The solvent evaporation is rapid and dry nanoparticles are produced before reaching the surface. In this study, we investigate the structure of nanoparticle deposits printed using electrospray. Using dark field microscopy, four regimes are identified that mark the evolution of the deposit structure at early times. Electrospray imparts an excess electric charge onto the emitted particles. It is shown that the mutual Coulombic interaction between the particles governs their transport and ultimately the microstructure of the printed deposits. Electrospray offers enhanced control over the microstructure of printed nanomaterial deposits compared to traditional printing techniques. This has significant implications for the manufacturing of flexible electronic and photonic devices.