Abstract
Photonic crystals exhibit exciting opportunities for controlling light. This can be utilized in optical waveguides, telecommunication devices, chemical and biological sensing and solar cells. However, functional devices require tuneable photonic crystals and ultimately structures that allow switching. Therefore inorganic-polymeric hybrid particles were developed, which offer new opportunities in the design of nanostructured materials since each component can be removed selectively. The presentation describes the synthesis of silica-polymer core-shell particles, absolutely uniform in size and in architecture. They were used as building blocks for colloidal crystals which served as templates for titania or tin disulfide inverse opals. Due to the inorganic - polymeric core-shell structure of the spheres, removing the polymeric shells by calcination yields the structure of Double Inverse Opal Photonic Crystals (DIOPC): The ordered, 3D array of air spheres in a high refractive index backbone is a host for movable silica spheres which behave as weakly scattering objects. The optical properties were determined by reflectivity measurements. Infiltration with liquids masks the silica-spheres optically, therefore introducing a transition of a diffusive scattering material to a selective reflection of specific wavelengths as known from ordinary inverse opals. This experiment simulates an order-disorder transition, induced by a collective shift of the random distributed silicaspheres into one specific position in the pores. The potential of switching a complete band-gap by a collective shift of the spheres to specific positions in the pores of the DIOPC is demonstrated by computational analysis.