Fluorescence and phosphorescence properties of Ba4(Si3O8)2:Eu2+, Re3+ (Re:Dy,Ho)

Abstract The long afterglow phosphors Ba 3.94 (Si 3 O 8 ) 2 :0.02Eu 2+ , 0.04Re 3+ (Re:Dy,Ho) were prepared by the high-temperature solid state reaction. Ba 3.94 (Si 3 O 8 ) 2 :0.02Eu 2+ , 0.04Ho 3+ exhibited a long-lasting phosphorescence whose duration was more than 4 h visible to the naked eyes, and the initial phosphorescence intensity was over 3 cd/m 2 ; Ba 3.94 (Si 3 O 8 ) 2 :0.02Eu 2+ , 0.04Dy 3+ exhibited a weak phosphorescence (the initial intensity: 0.3 cd/m 2 ) lasting for half hour. The crystal structure, excitation spectra, emission spectra, the fluorescence lifetime, long afterglow decaying curves and thermoluminescence (TL) curves of the two sample were obtained in our work, reflecting that the phosphorescence mechanism was different: the TL curve half width of Ba 3.94 (Si 3 O 8 ) 2 :0.02Eu 2+ , 0.04Dy 3+ was constant with different waiting time and the depth of the traps was about 0.748 eV, indicating that the process of releasing carriers was apt to the first order kinetics. However, the TL curve half width of Ba 3.94 (Si 3 O 8 ) 2 :0.02Eu 2+ , 0.04Ho 3+ decreased gradually indicating that the inner traps energy was not a single level but a energy band ranging from 0.608 eV to 1.156 eV.