Luminescence and energy transfer in Dy3+/Tb3+ co-doped transparent oxyfluorosilicate glass-ceramics for green emitting applications

• We produced SrF2 nanocrystals using melt-quenching and heat treatment processes.
• Energy transfer between the Dy3+ and Tb3+ ions have been discussed.
• Enhanced green emission observed in co-doped glass-ceramics by Tb3+ ion concentration.
• Green emission intensity was investigated by different pump wavelengths.
• Oxyfluorosilicate glass-ceramics could be useful for green LED applications.

Transparent oxyfluorosilicate glass-ceramics containing cubic SrF2 nanocrystals doped with Dy3+, Tb3+, and Dy3+/Tb3+ were successfully synthesized by melt quenching followed by heat treatment process. The crystalline phase of SrF2 nanocrystals during heat treatment was confirmed by X-ray diffraction. The emission intensity of glass-ceramics is much stronger than that of their parent glasses, on the one hand due to progressive incorporation of Dy3+ and Tb3+ ions within the SrF2 nanocrystals, on the other hand due to an efficient energy transfer from Dy3+ to Tb3+. Luminescence quantum efficiency of the samples was measured by using an integrating sphere. Luminescence decay curves of the 4F9/2 level were fitted to Inokuti-Hirayama (IH) model for analyzing the energy transfer rates between Dy3+ and Tb3+ ions. The chromaticity coordinates were determined from the measured emission spectra and they are located at the green and white light regions.

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