Evaporation-driven self-organization of photoluminescent organic dye-doped silica-poly(vinylpyrrolidone) hybrid films prepared by low-speed dip-coating

We prepared silica-poly(vinylpyrrolidone) (PVP) hybrid films containing a photoluminescent organic dye, rhordamine 6G (R6G), by low-speed dip-coating, where the spontaneous pattern formation was induced in the films. Stripe patterns arranged perpendicular to the substrate withdrawal direction were spontaneously formed by stick-slip motion at the meniscus during dip-coating, and the film structure (i.e., the film thickness, and the height, width and spacing of stripe patterns) was changed with increasing amounts of volatile solvent (C2H5OH) in solutions (C2H5OH/Si(OCH3)4 mole ratio (x) = 20–150). As a result of the optimization of the film structure, localized photoluminescence at the stripe patterns was achieved over x = 120.