Synthesis and photoluminescence properties of Eu doped LiBaPO₄ phosphors for solid state lighting

Abstract

Phosphor LiBaPO₄: Eu³⁺ was successfully synthesized by Pechini (citrate gel) method which is more efficient than conventional high temperature solid state diffusion reaction. X-ray diffraction analysis confirmed the single phase formation of LiBaPO₄ with hexagonal crystal structure. Luminescence results showed that the phosphor could be efficiently excited by near UV with intense excitation peak at 393 nm and exhibited two bright red emission narrow bands. In the wavelength range 575–640 nm these bands are centered at 595 and 615 nm, corresponding to characteristics transitions ⁵D₀→⁷F₁ and ⁵D₀→⁷F₂ respectively of Eu³⁺, with maximum intensity peak at 615 nm. When Eu³⁺ in LiBaPO₄:Eu³⁺ was reduced by the carbo-thermal reduction process to Eu²⁺ intense blue broad emission band centered at 472 nm was obtained for LiBaPO₄:Eu²⁺ phosphor when monitored at 350 nm. Hence both of phosphors could be use in solid state lighting application for fabrication of white light emitting diodes.