Luminescent properties of Li2 (Ca0.99, Eu0.01) SiO4: B3+ particles as a potential bluish green phosphor for ultraviolet light-emitting diodes

In our study, the 1% mol Eu²⁺ doped Li₂CaSiO₄: B³⁺ phosphors were prepared by the combustion method as fluorescent material for ultraviolet, light-emitting diodes (UV-LEDs) used as a light source. The properties of Li₂ (Ca_0.99, Eu_0.01) SiO₄: B³⁺ phosphors with urea concentration, doping boric acid and a series of initiating combustion temperature were investigated. The crystallization and particle sizes of Li₂ (Ca_0.99, Eu_0.01) SiO₄: B³⁺ has been investigated by using powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). Luminescence measurements showed that the phosphors can be efficiently excited by UV to the visible region, and exhibited bluish green light with a peak of 480 nm. The results showed that the boric acid was effective in improving the luminescence intensity of Li₂ (Ca_0.99, Eu_0.01) SiO₄: B³⁺ and the optimum molar ratio of boric acid to calcium nitrate was about 0.06. The optimized phosphors Li₂ (Ca_0.99, Eu_0.01) SiO₄: B _0.06 ³⁺ showed 180% improved emission intensity compared with that of the Li₂ (Ca_0.99, Eu_0.01) SiO₄ phosphors under ultraviolet (λ_ex =287 nm) excitation.