Titanium(IV) oxide thin films obtained by a two-step soft-solution method

TiO2 films were deposited on either glass or Si substrates by using a two-step soft-solution method. A submonolayer of anatase TiO 2 nanocrystals was first deposited on the substrate by a drain-coating process that was performed at 333 K from an aqueous TiO 2 colloidal solution. The substrate partially covered with the TiO2 nanocrystals was immersed in an aqueous solution, containing a titania precursor [fluorine-complexed Ti(IV)], and the whole was treated with microwave irradiation. The nanocrystals deposited on the substrate acted as growth seeds in the subsequent formation of the TiO2 film. The obtained TiO2 films showed a high degree of crystallinity (anatase), even without further thermal treatment; however, they did not show photocatalytic activity. Thickness of the films was varied as a function of microwave power and irradiation time. © 2002 Elsevier Science B.V. All rights reserved.