Titania Solid Thin Films Deposited by pp-MOCVD Exhibiting Visible Light Photocatalytic Activity

The crisis of hospital-acquired infections is driving intense interest in surface coatings that can inhibit colonization and reduce spread of pathogens to vulnerable patients. Widespread use of antibiotics and antimicrobial silver and copper has been demonstrated to trigger evolution of resistant strains of bacteria. The self-cleaning properties of TiO₂ could be a breakthrough for fighting HAI outbreaks if the photocatalytic activity (PCA) can be shifted to the spectrum of indoor light, and if a robust coating could be manufactured on hospital touch surfaces. MOCVD using titanium tetraisopropoxide (TTIP) is currently the standard method for applying self-cleaning TiO₂ to industrial glass. In this study, pulsed-pressure MOCVD (pp-MOCVD) was used to produce a solid coating composed of columnar microstructure anatase phase TiO₂ with 200 nm diameter. This microstructure has enhanced active surface area and co-deposited amorphous carbon on the crystal surfaces. The microstructure and carbon content were studied as a function of deposition temperature, and the new TiO₂ coating was demonstrated to exhibit significant PCA under standard indoor lighting.