Formation, densification and properties of sol–gel TiO2 films prepared from triethanolamine-chelated soluble precursor powders

Amorphous, soluble powders were synthesized with triethanolamine (TEA) as chelating agent as precursors for TiO2 sol–gel solutions. Dip coating on glass substrates and subsequent annealing yielded thin films with excellent optical properties. Furthermore as-dried films were scraped of substrates, annealed at different temperatures and characterized in order to investigate the structural changes during processing. The observations were systematically compared with previous studies on precursor powders based on acetylacetone. Results indicate that triethanolamine provides both a sufficient hydrolytical stability of the Ti-precursor during coating and an adequate plasticity of the film material throughout thermal densification. These characteristics significantly improve the practical workability of the respective process. Additionally former assumptions regarding the relationship between film properties and intermediate structural features were verified and refined.