Color-tunable and upconversion luminescence of Gd_2O_2S:Er,Tm phosphor: experimental investigations and first-principles calculation

摘要

The Er_(3+), Tm_(3+)co-doped gadolinium oxysulfide phosphors were prepared using solid-state reaction in vacuum. The crystal structure, morphology, and photoluminescence characteristics were, respectively, investigated by X-ray diffraction, transmission electron microscope, upconversion luminescence spectra and Commission Internationale de L’Eclairage diagram. Under 980 nm excitation, the quenching concentration of Er_(3+)was revealed to be 7 mol% with highest luminescence intensity and fluorescence lifetime. The emitting color of Gd~(2)O~(2)S:Er,Tm phosphors can be tuned by adjusting the concentration of Er_(3+)and Tm_(3+). First-principles calculation was employed to clarify the luminescence mechanism of the impurities doped in gadolinium oxysulfide host lattice by calculated band structure, density of states and absorption spectrum.