Luminescence and energy transfer of Eu/Mn 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).