Preparation and properties of gold-infiltrated polystyrene photonic crystals Original Research Article

Artificial opals are an important class of photonic crystals that can be used for a number of different applications. Here we describe a simple process for doping the voids of polystyrene-based three-dimensional photonic crystals with metal nano-particles. Our demonstration made use of nano-gold colloids but similar techniques can be used for incorporating nano-particles of other metals inside the interstices of self-assembled opals. A particularly attractive feature of our technique is that it allows thick opal films to be infiltrated easily with capillary forces transporting the active dopant inside the microporous material. The infiltration technique is described followed by a description of scanning electron microscopy performed on infiltrated samples. Gold nano-pillars with diameters of 35 nm have been observed between the domains and also on the (1 1 1) plane. The results of optical reflection experiments carried out on infiltrated opals are described next which show the presence of surface plasmon resonance bands.