Transparent antireflective layers of oxide nanowires grown from thin films by pressurized contact interdiffusion processes

Oxide phase nanowires are important for applications ranging from optoelectronics to water splitting, but prove difficult to grow in high density with good crystalline quality and phase purity. Heterogeneous catalysts are typically required to nucleate growth. This work demonstrates that dispersions of oxide nanowires can be formed directly from solution processed oxide thin films. We also examine the effect of changes in applied pressure between a solution processed vanadium oxide thin film and a surface-contacted glass coupon on the catalyst-free formation of interconnected sodium vanadate nanowire structures by interdiffusion. Under different applied pressures, meshes of high quality crystalline oxide nanowires formed on the surface, and we examine the nature of phase conversion and nanostructure growth including larger shards composed of multiple conjoined nanowires are also examined. The optical properties of the oxides NWs formed by interdiffusion from oxide thin films show promising properties for application as antireflective coatings across a broadband spectral range. This interdiffusion technique is effective for high quality oxide nanowire growth without catalysts directly from insulating or conducting thin films by direct contact with a source of diffusing species.