Two-Dimensional Ordered Arrays of Silica Nanoparticles

Abstract

Nanosized silica particles of various diameters (40, 60, and 105 nm) with relatively narrow size distributions were prepared via base-catalyzed sol−gel reactions of tetraethyl orthosilicate using a seeded-growth technique. These nanoparticles were organized into two-dimensional (2-D) monolayers by a solvent evaporation method. The particles of 60 nm or greater in diameter could be assembled to 2-D crystals on a larger area because of lower particle size distribution. The arraying order was found to have little or no dependence on shape regularity of the nanoparticles, pH value, and type of the substrate, including microslide, silicon wafer, and indium−tin oxide glass, used in this study.