Photoluminescence properties of Ho3+/Tm3+-doped YAGG nano-crystalline powders

Abstract

Y3Al4GaO12 (YAGG):(Tm3+, Ho3+) nanoparticles have been synthesized by Pechini sol-gel method and characterised their X-ray diffraction patterns, scanning electron microscope image, energy dispersive and photoluminescence spectra. From XRD results, phase purity and structure have been confirmed. Excitation spectra reveal that 363 nm excitation is suitable to excite the co-doped samples. Under ultraviolet excitation at 363 nm, the characteristic emissions of Tm3+ and Ho3+ ions have been observed in the photoluminescence (PL) spectra. Concentration dependent luminescence and energy transfer between Tm3+ and Ho3+ ions have been studied. The CIE chromaticity coordinates and correlated colour temperature values have been obtained from the emission spectra. Moreover, the emission colour of the YAGG:TmHo nano-powders was slightly shifted to red colour while increasing the Ho concentration and can be tuned from blue/green to white by adjusting the Tm3+/Ho3+ ions concentration. The optimum concentration of Tm3+ and Ho3+ ions were found to be 1:1 ratio in the YAGG host. The optimized single component white light emitting YAGG:TmHo phosphors could be a potential candidate for phosphor-converted white light emitting diode and full colour display applications.