Colour Tuning of Single Host Phosphors for White Light by AlAddition

Abstract

We report a newly found strong disturbing effect of Al addition tothe intensity ratios of blue and green emissions from single hostfull-colour phosphor ofBa3MgSi2−xAlxO8:0.02Eu2+, 0.1Mn2+ fornear-UV excited white light. The phase-pure silicatephosphor in the size of around 4 μm is prepared by salt-assisted spraypyrolysis route, having three-colour emissions at thewavelength peak values of 437 nm, 500 nm and 608 nm simultaneously underthe excitation of 375 nm. The amount variation of Al ion added to thephosphor host results in a drastic change of the intensity ratiobetween green and blue emissions, while the intensity of red lightkeeps unchanged. As a consequence, the combination of three colourslies in the white light region and can be tuned by precisely controlledaddition of Al content. The Raman spectroscopy verifies the modifyingeffect of Al ion to the tetrahedral network in silicate hosts. Weassume that by addition of Al ion, the amount of those two kinds ofEu2+ substituting for those two kinds of Ba2+ lattice siteswith distinct energy levels of blue and green featured emissions can beadjusted to contribute to diversification of the ratios of blue and greenemissions.