Directed assembly of nanomaterials using electrospray deposition and substrate-level patterning

We report on the use of electrospray deposition and electrostatic focusing provided by a patterned photo-resist layer to direct the assembly of nanomaterials on to a target substrate. Metallic (silver), semiconducting (titanium dioxide), and dielectric (polystyrene) particles were electrospray printed onto silicon and glass substrates with periodic photoresist patterns. The assembly and structure of the deposit was governed by the spray time, print material, substrate electrical properties, and geometry of the photoresist layer. The deposited particles could maintain an excess electric charge that influenced the assembly of subsequent particles. Tall, tree-like structures with high aspect ratio were formed on the silicon substrate when using silver and titanium dioxide particles. The growth of the deposit was inhibited for the polystyrene particles or when the target was glass. This technique was used to build two-layer deposits of different materials without having to align one layer to the next. (C) 2020 Elsevier B.V. All rights reserved.