The objective of this study is to develop a procedure for controlling the deposition of colloidal crystal coatings from
nanoparticle suspensions. We experimentally deposited polystyrene nanospheres on glass plates by dragging a small
volume of liquid over the substrates. The mechanism governing the deposition is convective assembly. It has been
observed that the number of deposited nanosphere layers can be influenced by the deposition speed and the nanosphere
volume fraction, as predicted by theory. Crystal coatings of a few square centimeters were deposited in minutes from
suspensions of 5 - 20 μL. Our computer simulations of the phenomena generated structures similar to those from
experimental films, proving the validity of the model elaborated for the assembly process.
We report on the unusually high optical transmitivity of silver coated two-dimensional colloidal crystals. Our sample consists
of a 50 nm silver film deposited on top of a regular two-dimensional array of polystyrene spheres of 400 nm diameter. Two-dimensional
colloidal crystals were prepared according to the drop-coating technique, and subsequently covered in a silver
film by thermal evaporation. Morphology of the crystal was checked by means of scanning electron microscopy. We
measured transmission through the composite metallo-dielectric films at normal and also oblique incidence. Additional
reflectance spectra and surface enhanced Raman scattering are used to understand the optical/plasmonic properties of the
prepared nanostructure. Dependence of the spectral features on incident angle suggests highly localized optical/plasmonic
modes are involved in the mechanism of transmission.