Photoluminescence characterization of Ce 3+ and Dy 3+ doped Li 2CaGeO 4 phosphors

Abstract

Ce 3+ and Dy 3+ activated Li 2CaGeO 4 phosphors were prepared by a solid-state reaction method, and characterized by XRD (X-ray diffraction) and photoluminescence techniques. The characteristic emission bands of Dy 3+ due to 4F 9/2→ 6H 15/2 (blue) and 4F 9/2→ 6H 13/2 (yellow) transitions were detected in the emission spectra of Li 2CaGeO 4:Dy 3+. Ce 3+ broad band emission was observed in Li 2CaGeO 4:Ce 3+ phosphors at 372 and 400 nm due to 5d→4f transition when excited at 353 nm. Co-doping of Ce 3+ enhanced the luminescence of Dy 3+ significantly and concentration quenching occurs when Dy 3+ is beyond 0.04 mol%. White-light with different hues can be realized by tuning Dy 3+ concentration in the phosphors.