Characterization of luminescent praseodymium-doped ZrO₂coatings deposited by ultrasonic spray pyrolysis technique

Abstract

ZrO2 : Pr films were synthesized by the ultrasonic spray pyrolysis process. X-ray diffraction studies, as a function of the deposition temperature, indicate a tetragonal crystal structure of zirconia as the substrate temperature was increased. Luminescence (photo- and cathodoluminescence) properties of the films were studied as a function of growth parameters such as the substrate temperature and the praseodymium concentration. For an excitation wavelength of 290 nm, all the photoluminescent emission spectra show peaks located at 490, 510, 566, 615, 642, 695, 718, 740 and 833 nm, associated with the electronic transitions 3 P0 → 3 H4, 3 P0 → 3 H4, 3 P1 + 1 I6 → 3 H5, 1 D2 → 3 H4, 3 P0 → 3 H6, 1 D2 → 3 H5, 1 D2 → 3 H5, 3 P0 → 3 F3,4 and 1 D2 → 3 F2 of the Pr 3+ ion. As the deposition temperature is increased, an increasing intensity of the luminescence emission is observed. Also, quenching of the luminescence, with increasing doping concentration, is observed. The chemical composition of the films as determined by energy dispersive spectroscopy is reported as well. In addition, the surface morphology characteristics of the films, as a function of the deposition temperature, are presented.