Photonic band gap thin films from mesoporous silica spheres acting as receptacles for species yielding added functionality

We demonstrate that mesoporous silica particles capable of acting as receptacles for functional nanoparticles may be readily synthesized and then assembled into photonic crystal thin films displaying well-defined Bragg diffraction features in the visible region. We show that it is possible to tailor not only the particle diameter, but also the pore diameters within the particles. As an example of the possible application of such particles in photonic crystal fabrication we show that it is possible to deposit Fe₂O₃ nanoparticles on the exterior of and inside the pores of hexagonal phase mesoporous silica spheres.