Sol–gel preparation of well-adhered films and long range ordered inverse opal films of BaTiO3 and Bi2Ti2O7

Barium and bismuth titanate thin films and well-ordered inverse opal films are produced by dip coating from sols containing titanium alkoxides with acetic acid, acetylacetone, methoxyethanol and water. The inverse opal preparations used crosslinked polystyrene opal templates. Heat treatment in air produced tetragonal BaTiO3 or mixtures of the hexagonal and tetragonal phases, or phase pure Bi2Ti2O7. Good quality films were obtained with a thickness of 5 μm from a single dipping, and the thickness could be increased by dipping multiple times. Inverse opals were well ordered and exhibited opalescence and photonic stop band effects.