STUDIES ON THE SYNTHESIS AND LUMINESCENCE PROPERTIES OF (Li,Ca,Gd) SiO_3 :Eu, Bi LUMINOPHORS

The luminophors of silicate (Li, Ca, Gd) SiO3:Eu, Bi were- sythesised and luminescence properties of Bi3+, Eu3+, and Gd3+ ions were studied. The effects and regularities of Gd3+ ion on the luminescence of Eu3+ and Bi3+ ions were investigated. The study on the luminescence of silicates (Li, Ca, Gd) SiO3:Eu, Bi shows that there are energy transitions from Bi3+ ion to Eu3+ ion and that Bi3+ ions act as both sensitizers and co-activators and that the spectral energy distribution of the luminophors depends on the Gds+ ion content. It is shown that Gd3+ ion can greatly promote the sensitive effect of Bi3+ on Eu3+ and turn the main emission of Eu3+ ion from 6Do-7F1 to 5Do-7F2 transition as the condensations of Gd3+ ion increase.Under UV excitation of 393 nm, the luminescence intensities of Eu3+ in Lio.sOa0.4Gd0.268SiO3Eu0.025Bi0.007 are the same as or more than those of Y(V, P)O4: Eu for either 5Do-7F1 or 5Do-7F2 transition emission. The experiment results show that the optimum synthesis conditions are 950℃ and 4hrs fired twice for Li0.30 Ca0.40 Gd0.30SiO3:Eu, Bi and that silicate Li0.30 Ca0.40 Gd0.30 SiO3 is an excellent host lattice to obtain efficient photoluminesoent materials.

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