Luminescence properties of Ce-Dy codoped aluminium oxide films

Photoluminescence properties of CeCl₃ and DyCl₃ codoped aluminium oxide films deposited by the ultrasonic spray pyrolysis technique were characterized by excitation, emission and decay time spectroscopy. When excited by ultraviolet radiation the films emit a combination of blue and yellow wavelengths through an efficient energy transfer from Ce³⁺ to Dy³⁺ ions (up to around 77%). From spectroscopic data it is inferred that such energy transfer is nonradiative in nature taking place between Ce³⁺ and Dy³⁺ clusters through a short-range interaction mechanism. In the Ce³⁺ doped single film the chromaticity coordinates are in the purplish blue region, whereas that in the cerium and dysprosium codoped films the coordinates move toward the white light emission region.