Synthesis and Luminescence of Eu~(2+) activated yellow oxynitride phosphor

摘要

In this paper, we discuss synthesis and luminescence properties of a novel yellow phosphor composition, Ba_4Si_9(O,N)_(16-δ):Eu~(2+) (YON). The powder x-ray diffraction pattern indicates formation of a new oxynitride phase with a minor secondary phase of BaSi_7N_(10) . To our knowledge, the composition and luminescence properties of this oxynitride material has not been reported earlier. YON crystallizes in monoclinic crystal system with unit cell parameters a=5.7598(1)A, b=7.0499(1)A, c=9.6315(1)A, β = 107.362(1). The Eu~(2+) activated material shows efficient yellow emission peaking around ～580nm under UV/blue excitation. The emission position can be tuned by Sr~(2+)/Ca~(2+) substitution in the Ba~(2+) site. We also investigate the nature of their emission at different Eu~(2+) concentration levels and at elevated temperatures. Warm white lamps built using phosphor blends with this new phosphor are capable of making high CRI, warm white lamps with high lumen equivalents (＞325 lm/W_(opt)).