Luminescence and energy transfer of Eu2+/Mn2+ co-doped SiO2-Al2O3-ZnO-K2O glass ceramics for white LEDs

Transparent Eu2+/Mn2+ co-doped new glass ceramics (GC) containing β-Zn2SiO4 nanocrystals were prepared under a reduced atmosphere. The optical properties of these samples have been investigated. The emission spectra of Eu2+/Mn2+ co-doped glass ceramics show two broadband peakings at 458 and 560 nm under ultraviolet radiation, which can be attributed to 4f65d1→4f7 transition of Eu2+ and 4T1(4G)→6A1(6S) transition of Mn2+, respectively. Energy transfer (ET) from Eu2+ to Mn2+ is discovered by directly observing significant overlap of the excitation spectrum of Mn2+ and the emission spectrum of Eu2+. ET from Eu2+ to Mn2+ in glass ceramics is further confirmed by fluorescence studies performed on the samples with various activator (Mn2+) concentrations. The optimal composition generates white light with chromaticity coordinates (0.291, 0.344). The results indicate that Eu2+/Mn2+ co-doped glass ceramics is potential material for white light-emitting diodes (LEDs).