Effect of doping concentration on particle growth and luminescence properties of monodispersed Dy³⁺: Y₂O₃

Submicron-sized Dy³⁺: Y₂O₃ particles were successfully prepared via an urea homogeneous precipitation method, followed by a calcination at 800 °C. TG-DSC, FT-IR, X-ray diffraction (XRD), Field emission scanning electron microscope (FE-SEM), scanning electron microscope (SEM), photoluminescence (PL), and photoluminescence excitation (PLE) spectra were used to characterize the prepared samples. The particles were spherical shape and monodispersed. More importantly, the spherical Y₂O₃ particles were found to have significant changes in size with varying dopant concentration of the Dy³⁺ ions, ranging approximately from 550 to 840 nm. The possible growth mechanism of the particles was proposed. Under 349 nm excitation, the crystalline powders exhibited blue and yellow emissions due to the ⁴F_9/2 → ⁶H_15/2 and ⁴F_9/2 → ⁶H_13/2 transitions of Dy³⁺ ions, respectively. It was further found that with proper Dy³⁺ doping concentration, the luminescence color hue was tuned close to the ideal white light with color coordinates of (0.33, 0.33). The submicron-sized Dy³⁺: Y₂O₃ phosphor is a promising candidate for the white light emitting diodes (WLEDs).