Eu 2+/Dy 3+ co-doped white light emission glass ceramics under UV light excitation

Abstract

In the present work, transparent Eu 2+/Dy 3+ co-doped white light-emitting glass ceramics containing CaF 2 were successfully prepared under reducing atmosphere. Their luminescence properties have been studied by excitation and emission spectra. A combination of blue, yellow and red emissions has emerged in Eu 2+/Dy 3+ co-doped glass and glass ceramics, which allows the observation of bright white light when the samples are excited by the ultraviolet light. Energy transfer (ET) from Eu 2+ to Dy 3+ is discovered by directly observing the luminescence intensity of Dy 3+ in the Eu 2+/Dy 3+ co-doped glass which is much stronger than that in the Dy 3+-doped glass. ET from Eu 2+ to Dy 3+ in glass is further confirmed by fluorescence studies performed on the samples with various activator (Dy 3+) concentrations. The color of luminescence could be adjusted by varying the proportions of europium and dysprosium. The optimal composition generates white light with chromaticity coordinates (0.296, 0.311). The results indicate that Eu 2+/Dy 3+ co-doped glass ceramics containing CaF 2 nano-crystals is a potential material for white LED.