Synthesis and photoluminescence properties of Eu doped LiBaPO_4 phosphors for solid state lighting

摘要

Phosphor LiBaPO_4: Eu~(3+) 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 LiBaPO_4 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 ~5D_0→~7F_1 and ~5D_0→~7F_2 respectively of Eu~(3+), with maximum intensity peak at 615 nm. When Eu~(3+) in LiBaPO_4:Eu~(3+) was reduced by the carbo-thermal reduction process to Eu~(2+) intense blue broad emission band centered at 472 nm was obtained for LiBaPO_4:Eu~(2+) 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.