| Spherical phosphors have broad applications in the field of lighting.This paper focuses on the preparation and luminescent properties of spherical Y2O3:Mn and YSO/YPS:Eu,respectively.SiO2@(Y,Eu)(OH)CO3 precursors with particular core-shell structure were prepared by urea homogeneous precipation method on the surface of spherical SiO2,in which SiO2 was regared as the core material.The YSO/YPS:Eu phosphors were produced successfully though annealing the precursors.The effects of Y/Si ratio,calcination temperature and Eu3+doping concentration on the morphology,phase composition and photoluminescence of the phosphors were investigated,respectively.The spherical Y2O3:Mn powders were prepared by the method of urea homogeneous precipation,and their luminescent properties were studied.The influences of Mn2+and Bi3+codoping on the luminescent properties were also studied.The main conclusions are as follows:(1)The Y/Si ratio controls the partical size,shell thickness and dispersion of core-shell precursor powders.After being calcined above 1000℃,the core-shell precursors are in turn formed yttrium-europium oxide phase,YSO phase,and YPS phase.The photoluminescence spectrum changes as the crystal lattice changes.In the spectrum of YSO/YPS:Eu,5D0→7F4 has similar emission intensity with 5D0→7F2,which is different from the spectrum of Y2O3:Eu3+that the SD0→2F2 emission is dominant.The emission intensity of 5D0→7F2 decreases gradually with the phase transformation of yttrium oxide phase to YSO phase and YPS phase.(2)The study found that the luminescent intensity of Y2O3:Mn is weak due to paritiy and spin forbidden.By co-doping Mn2+ and Bi3+,the luminous intensity has a sharp increase around 500 nm.After calcination at 1000℃,1100℃ and 1200℃,respectively,Yttrium co-doped with 1 at.%Mn2+and 1 at.%Bi3+has the highest emission intensity compared with Y2O3 only doped with 1 at.%Bi3+,in which the strongest emission intensity is 1.64,1.67 and 1.22 times than that of the 1 at.%Bi3+doped yttrium oxide. |
PDF Full Text Request