Synthesis and photoluminescence of Gd_2O_2SO_4∶Dy~(3+) nano-phosphors by a co-precipitation method

Gd2O2SO4∶Dy3+ nano-phosphors were synthesized by a co-precipitation method from Gd2O3,Dy2O3,H2SO4 and NaOH starting materials.The characterizations of Gd2O2SO4∶Dy3+ nano-phosphors were investigated by means of XRD,TEM and PL spectra.XRD analysis shows that the precursor can be transformed into pure Gd2O2SO4∶Dy3+ nano-phosphor by calcining at 900℃ for 2h in air.TEM observation shows that the Gd2O2SO4∶Dy3+ phosphor particles are quasi-spherical in shape and well dispersed,with a mean particle size of about 20-40nm.Photoluminescence(PL)spectroscopy reveals that the main and second emission peaks are located at 575 and 485nm under 277nm UV light excitation,which corresponds to the 4F9/2→6H13/2 and the 4F9/2→6H15/2 transitions of Dy3+ ions,respectively.The quenching concentration of Dy3+ ions is 2mol% and the concentration quenching mechanism is exchange interaction among the Dy3+ ions.Decay study reveals that the 4F9/2→6H13/2 and 4F9/2→6H15/2 transitions of Dy3+ ions have a single exponential decay behavior with a corresponding lifetime of 0.468 and 0.462ms,respectively.