Effect of fluxes on luminescence properties of color-tunable Ba_(1.3)Ca_(0.7)SiO_4:Eu~(2+) , Mn~(2+) Phosphor for Near-Ultraviolet White-LEDs

摘要

Eu2+/Mn2+-codoped Ba1.3Ca 0.7SiO4 (BCS), a promising single-phase and white-light-emitting phosphor, is prepared by the solid-state reaction at a calcination temperature of 1000 degrees C for 2 h by adding SrCl2, CaCl2, KCI, NaCl, NH4Cl, Li2CO3, BaF2, CaF2, and BaCl2 as fluxes. The samples are characterized by X-ray diffraction and photoluminescence spectroscopy. The emission wavelength and color-rendering index (CRI) can be tuned by adjusting the amount of the BaCl2 flux and are influenced by the different flux types. NH4Cl exhibits the best fluxing effect for the Mn2+ ion doping probably because the formed eutectic mixtures of BaCl2 -CaCl2 during the reaction process promote the reaction. The phosphors produced by adding a SrCl2 flux exhibit the highest CRI of 87.2 with Commision International de I'Eclairage (CIE) chromaticity coordinates of (0.347, 0.343) in the white region under near-ultraviolet light excitation.