Sol-gel preparation and characterization of transparent GdTaO 4 : Eu3+thick films

Transparent luminescent films have been believed to have the potential applications in high spatial resolution X-ray imaging system. However, it is usually restricted by the thickness of the film. Instead of alkoxide, GdTaO₄:Eu³⁺ film with a thickness of about 0.8 μm was prepared from an inorganic salt-2-methoxyethanol solution containing polyvinylpyrrolidone (PVP) as an additive via single-step spin coating. The whole process was carried out without inert atmosphere which is necessary for alkoxides. The fired film is optically transparent and crack-free, and exhibits a strong luminescence at 611 nm under X-ray excitation.