A facile layer-by-layer adsorption and reaction method to the preparation of titanium phosphate ultrathin films

A layer-by-layer adsorption and reaction method was developed for the preparation of titanium phosphate ultrathin films. By repetitive adsorption of hydrated titanium from aqueous Ti(SO4)(2) solution and subsequent reaction with phosphate groups, ultrathin films of titanium phosphate were fabricated. Regular film growth was verified by UV-vis absorption spectroscopy and quartz crystal microbalance measurements. The film composition is mainly Ti(HPO4)(2), as confirmed by X-ray photoelectron spectroscopy and FT-IR spectroscopy. The as-prepared titanium phosphate films are uniform, highly stable, and their thickness can be well controlled by adjusting the number of adsorption-reaction cycles and pH value of Ti(SO4)(2) and phosphate salt solutions. The layer-by-layer adsorption and reaction method provides a facile way to prepare ultrathin films of titanium phosphate and other kinds of metal phosphates.