Controllable luminescence in Eu2+-doped Li2Sr2Al(PO4)3 phosphor via tuning the Eu2+ concentration and codoping Ce3+.

Abstract In this work, blue-emitting aluminophosphate phosphor, Li 2 Sr 2 Al(PO 4) 3 :Eu2+, was prepared by the solid state reaction. The influence of Eu2+ concentration on the excitation and emission characteristics of Li 2 Sr 2 Al(PO 4) 3 :Eu2+ has been studied using optical spectroscopy techniques. Upon near UV-light excitation, Li 2 Sr 2 Al(PO 4) 3 :Eu2+ generates a blue band peaked at 445 nm, and a violet band centered at 398 nm, which originate from Eu2+ ions occupying two kinds of crystallographic sites: Sr(1)O 8 and Sr(2)O 9 , respectively. The luminescence intensities of Eu1 and Eu2 have the strong dependence on the Eu2+ concentration. The contribution of Eu2+ luminescence from Eu1 becomes dominant with high Eu2+-doping. Li 2 Sr 2 Al(PO 4) 3 doped with high level of Eu2+ exhibits a strong narrow-band blue emission with a full width at half-maximum of about 42 nm. Meanwhile, the Eu2+ emission can be efficiently enhanced by codoping with Ce3+ ions using exclusive excitation into the Eu2+ absorption band. The mechanism of luminescence enhancement caused by Ce3+ ions has been determined. These results indicate that Li 2 Sr 2 Al(PO 4) 3 :Eu2+,Ce3+ phosphor might be competitive as a potential blue-emitting phosphor for white LEDs. Graphical abstract Image 1 Highlights • Blue-emitting Li 2 Sr 2 Al(PO 4) 3 :Eu2+,Ce3+ phosphor has been prepared. • Two type of Eu2+luminescent centers are identified in Li 2 Sr 2 Al(PO 4) 3 host. • The sensitization effect of Ce3+ on the Eu2+ emission has been determined. [ABSTRACT FROM AUTHOR]