Enhanced white light emission from Dy3+/Ce3+ codoped GdAl3(BO3)4 phosphors by combustion synthesis

Polycrystalline GdAl3(BO3)4 sub-micrometer-sized phosphors doped with rare-earth ions has been prepared by combustion synthesis method with urea. The phosphors have been characterized by X-ray diffractometer, thermogravimetric analysis/different scanning calorimeter and scanning electron microscope. Intense emissions centred at 480, 573 and 664 nm, originated from the transitions of 4F9/2→6H15/2, 4F9/2→6H13/2 and 4F9/2→6H11/2 of Dy3+, respectively, have been observed upon excitation of ultraviolet-blue light. Concentration quenching occurs when Dy3+ ions is beyond 3 mol.% due to the cross-relaxation of Dy3+. Codoping of Ce3+ has enhanced the luminescence of Dy3+ quite significantly and the optimum dopant concentration of Ce3+ is 7 mol.%. It is noted that the values of yellow-to-blue integral intensity of codoped GdAl3(BO3)4:Dy,Ce phosphors decrease with an increase of Ce3+ concentration. The chromaticity coordinates and colour temperatures of Dy3+ doped and/or Dy3+/Ce3+ codoped GdAl3(BO3)4 have been calculated and analysed with Commission Internationale l'Eclairage (CIE) diagrams