Desired warm white light emission from a highly photostable and single-component Gd2TiO5:Dy3+/Eu3+ nanophosphors for indoor illuminations

Abstract

At present, phosphor-converted white light-emitting diodes (pc-WLEDs), developed by combining an ultraviolet (UV)/near-UV (NUV) LED and a single-component white emitting phosphor, have attracted significant interest and are emerged as the new-generation green light sources. Herein, we report a highly photostable and novel Gd2TiO5 (GT):Dy3+/Eu3+ nanophosphors as single-component white emitting phosphors by sol-gel route. Based on X-ray diffraction pattern, Rietveld refinement is performed to authorize the orthorhombic phase of the GT nanophosphors. The nanosized particles with nearly spherical morphology is perceived after annealing at 1100 ℃. The Dy3+ and Eu3+ ions individually-doped GT nanophosphors exhibited pleasant white and reddish-orange emissions by monitoring with their respective excitation wavelengths. Tunable white light emission is achieved by co-doping the various concentrations of Eu3+ ions to the optimized GT:1.5Dy3+ nanophosphors under both UV (270 nm) and NUV (362 nm) excitations. The energy transfer probability is discussed and the energy transfer efficiency from Dy3+ to Eu3+ ions is calculated from the luminescence decay profiles. On rising the Eu3+ ions content from 0.25 to 6 mol%, the energy transfer efficiency is increased from 14% to 73% for co-doped GT nanophosphors. Besides, the optimized samples of Dy3+ and Eu3+ ions individually-doped and co-doped GT samples exhibited high quantum efficiencies and increased photostability. Thus, the acquired results signifying that these GT:Dy3+/Eu3+ nanophosphors can serve as potential single-component white emitting phosphors for UV and/or NUV-based pc-WLEDs.