Abstract: The recent advances of the authors’ study on the synthesis of large-area 3D ordered macroporous titania film photonic crystals by using silica colloidal crystals as
templates were presented. The main procedure of the preparation was described as follows. Firstly, the silica colloidal crystal template was deposited
onto a glass micro slide through a convective assembly process in which monodispersive silica spheres of 309nm were used. Secondly, after sintered at
600℃ for 1h the crystalline template was immersed vertically into a TiO₂ sol for the infiltration of the template. Thirdly, the
resulting titania-opal composite film was immersed in an aqueous NaOH solution for 24h to remove the silica template. By means of the systematical
study of the processes and application of some innovative processing techniques such as silica colloidal crystal templating technique, alkali based
template-etching technique, the highly ordered macroporous TiO₂ film photonic crystals with sizes of centimeters were successfully fabricated.
The results show that the shrinkage of the macroporous framework with a filling rate of 17.4% is less than 3%. The XRD pattern shows that the porous framework consists
of nanocrystallites of anatase mixed with a magnéli phase (Ti₅O₉). The optical property measurements of the films indicate that the
film photonic crystal has strong photonic bandgap behavior.

Key words: 3D ordered structure, inverted-opal structure, TiO2 film photonic crystal