Following thermal evolution of mesoporous TiO2: from the sol to the oxide

Abstract

Mesoporous TiO2 thin films have been extensively studied and applied in the construction of a wide variety of devices. To this end, it is critical to obtain detailed structural information regarding film formation and processing. However, there is still a lack of information about their chemical identity during thermal treatment, in which a transition from a hybrid mesostructure to a mesoporous matrix occurs. In this work, we present the FTIR characterization of three different mesoporous TiO2 films, templated with Brij 58, Pluronic F127 and Pluronic P123. The FTIR spectra were followed in situ from the sol deposition, through the thermal treatments until reaching 400 °C, using a high temperature cell. A detailed analysis taking into account all of the sol’s components and all the spectral regions in the range 3600–650 cm−1 was performed. The results obtained were compared with thermal analysis, coupled with mass spectrometry analysis of the released species. By this means, all the stages of the processing (solvent evaporation, template elimination and precursors condensation) were identified, and we were able to determine which chemical species are present at every treatment step. The results presented here can be useful when choosing processing conditions adapted for the final application of the TiO2 films.