Abstract: GdAlO₃:Tb,RE phosphor powder was prepared by nitric-citric process. Under UV light excitation(254 nm), it gave green emission(⁵D₄→⁷F₅,544 nm). The green luminescence intensity of GdAlO₃:Tb increased when it was co-doped with Dy, and decreased when co-doped with Ce. Excitation spectra and Energy level sketch indicate that Dy energy level is embedded between Tb ⁵D₄(green emission level) and Tb⁵D₃ (blue emission level), while Ce energy level is embedded above both ⁵D₄ and ⁵D₃. There are the resonant energy transfers between RE ions by the absorbing or emitting phonons, Tb→Dy→Tb energy transfer increases the green emission (⁵D₄→⁷F_J(J=3,4,5,6))and decreases the blue emission(⁵D₃→⁷F_J(J=3,4,5,6)); but Ce→Tb energy transfer increases the blue emission and decreases the green emission.

Key words: gadolinium-aluminum perovskite, luminescence, energy transmission, citrate-nitrate combustion