Formation of Patterned Colloidal Nanoparticle Superlattices in a Two Solvent System

A two solvent system consisting of a high boiling point solvent and a low boiling point solvent was found to greatly aid the self-assembly ofapproximatel -layer thicknanoparticle superlattices. Nanoparticle mixtures were prepared under multiple solvent evaporation conditions in a system of capillary channels patterned on Si substrates. The resulting films were to be highly ordered, and analyzed by SEM Grazing Incidence Small Angle X-ray Scattering(GISAXS).. capillary effect, introduced by patterned susbtrate the evaporation rateof solvents the channels are believed to be the driving factor the self-assemblyof the superlattices. Three-dimensional icrometer-scale superlattices of CdSe and Fe$_{2}$O$_{3}$ nanoparticles were fabricated this technique.