While nanoparticles themselves are expected to exhibit interesting properties, we expect to find more interesting properties by arranging them. The simplest method to achieve this arrangement is to synthesize nanoparticles with a consistent size and arrange them when applying them to a substrate.
Application-and-dry is the easiest method. When a nanoparticle dispersion liquid is prepared with an appropriate amount of an appropriate solvent, the nanoparticles will be densely and bidimensionally arranged. The distance among the nanoparticles is controlled by the size of the molecules of the protective agent, their thickness on the surface of the nanoparticle, and their molecular density.