High quality ordered macroporous titania films with large filling fraction

Large-area three-dimensionally ordered macroporous titania films have been fabricated by silica colloidal crystal templating. The matrix was obtained through a dip-infiltrating sol-gel process, with subsequent removal of the silica microspheres by chemical etching. Scanning electron micrograph confirms the ordering of the macroporous structure, and transmission spectra of the crystal show a pronounced attenuation dip which shifts when different solvents are infiltrated. Bragg's law at normal incidence was used to calculate the filling fraction of the titania backbone.