The self-assembly of colloids at air–water interfaces is a convenient method for the creation of high-quality, large-scale hexagonal 2D colloidal crystals. Here, we use nanoparticles containing metal complexes in two different processes for the creation of functional colloidal monolayers. After combustion of the polymer by plasma treatment, an array of metal nanoparticles is created that features the same symmetry and lattice spacing as the original colloidal monolayer.