Photoluminescence characterization of Ce3+ and Dy3+ doped Li2CaGeO4 phosphors

Ce3+ and Dy3+ activated Li2CaGeO4 phosphors were prepared by a solid-state reaction method, and characterized by XRD (X-ray diffraction) and photoluminescence techniques. The characteristic emission bands of Dy3+ due to 4F9/2→6H15/2 (blue) and 4F9/2→6H13/2 (yellow) transitions were detected in the emission spectra of Li2CaGeO4:Dy3+. Ce3+ broad band emission was observed in Li2CaGeO4:Ce3+ phosphors at 372 and 400 nm due to 5d→4f transition when excited at 353 nm. Co-doping of Ce3+ enhanced the luminescence of Dy3+ significantly and concentration quenching occurs when Dy3+ is beyond 0.04 mol%. White-light with different hues can be realized by tuning Dy3+ concentration in the phosphors.