Electrospray Deposition of {200} Oriented Regular-Assembly BaTiO₃ Nanocrystal Films under an Electric Field

Highly oriented, regularly assembled nanocrystalline films have recently emerged as attractive new functional materials. In this study, we deposited a BaTiO₃ (BT) nanocube dispersion on a Si substrate by electrospraying, resulting in a dense, regularly assembled BT nanocrystalline film. X-ray diffraction analysis revealed that applying a voltage between the electrospray nozzle and the Si substrate during electrospraying caused the BT nanocubes to form a regular array in the 200 plane aligned perpendicularly to the substrate. The volume fraction of BT nanocubes in the 200 plane in the assembly was estimated by the orientation distribution function analysis to be about 50%. The formation of this regularly assembled layer was determined to be linked to the interaction between the vaporized solvent and the substrate, enabled by the enhanced wettability under the electric field. Electrospray deposition has potential applications in the manufacture of nanocrystalline assembled films for nanofunctional devices.