Large enhancement in upconverted green emission intensity from Ho 3+ /Yb 3+ co-doped Y 2 Ti 2 O 7 phosphor in the presence of Zn 2+

Abstract

The Ho 3+ , Yb 3+ co-doped Y 2 Ti 2 O 7 phosphor samples have been synthesized through solid state reaction method in the absence and presence of Zn 2+ ions. The X-ray diffraction (XRD) analysis show that the phase of the crystal is face centered cubic. The zinc free phosphor shows weak upconversion emission in green region due to 5 S 2 , 5 F 4 → 5 I 8 transition of Ho 3+ ion on excitation with 980 nm radiation. The emission intensity is enhanced significantly in the presence of Zn 2+ ions due to increase in crystallinity, particle size and asymmetry in the crystal field. We are reporting ˜92 times enhancement in the green emission intensity for 30 mol% co-doping of Zn 2+ ions. The lifetime of 5 S 2 level of Ho 3+ ion increases by increasing the concentration of Zn 2+ ions. The intense green emission in this material may be suitable for display and other fluorescence based devices. © 2019 Elsevier Ltd