Optical Properties and Microstructures of Colloidal Crystalline Arrays 2007-01-1010
Colloidal crystalline arrays are three dimensionally periodic lattices of self-assembled monodisperse colloidal spheres. We have demonstrated the synthesis of silica or polystyrene spheres uniformly coated with titania nanosheets and the fabrication of these spheres into close-packed colloidal crystalline arrays. The Bragg diffraction peak of the colloidal crystalline array shifted to longer wavelengths with increasing thickness of titania nanosheets layers. Angle-resolved reflection spectra measurements showed that this red shift was caused by increasing the mean effective refractive index neff of this crystalline lattice without changing interplanar spacing d111 with increasing thickness of titania nanosheets layers.