White-light-emitting Eu~(2+) and Mn~(2+)-codoped silicate phosphors synthesized through combustion process

摘要

The Ba_3MgSi_2O_8:Eu~(2+) , Mn~(2+) phosphors are synthesized through combustion process with varying mixture ratio of citric acid and ethylene glycol used as a fuel to the used precursors. They have the mean particle size of 200 nm and the spherical shape. The Ba_3MgSi_2O_8:Eu~(2+), Mn~(2+) phosphors show three emission colors: the blue color of 433 nm from Eu~(2+) (Ⅰ) substituted by Ba~(2+) (Ⅰ) site, the green color of 500 nm from Eu~(2+)(Ⅱ, Ⅲ) substituted by Ba~(2+)(Ⅱ, Ⅲ) site, the red color of 610 nm from Mn~(2+)(Ⅰ,Ⅱ, Ⅲ). Compared with a solid-state method-prepared sample, the emission peaks of three emission bands are shifted to about 10 nm towards the shorter wavelength. This blue shift is explained by quantum size effect. The relative intensity ratios of the green band to the blue band are significantly increased as the increasing amount of fuel suggesting that Eu~(2+) ions in our sample preferably occupy Ba~(2+) (Ⅱ, Ⅲ) sites related to the green emissions.