Synthesis and Luminescence of Eu²⁺ Activated Yellow Oxynitride Phosphor

In this paper, we discuss synthesis and luminescence properties of a novel yellow phosphor composition, Ba4Si9(O,N)16- d:Eu2+ (YON). The powder x-ray diffraction pattern indicates formation of a new oxynitride phase with a minor secondary phase of BaSi7N10 . 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)Å, b=7.0499(1)Å, c=9.6315(1)Å, b = 107.362(1). The Eu2+ activated material shows efficient yellow emission peaking around ~580nm under UV/blue excitation. The emission position can be tuned by Sr2+/Ca2+ substitution in the Ba2+ site. We also investigate the nature of their emission at different Eu2+ 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 (&gt;325 lm/Wopt).</jats:p

Advances in the Development of Quantum Splitting Phosphors

ABSTRACTQuantum splitting phosphors (QSPs) are phosphors that could convert VUV radiation into more than one visible photon. These phosphors have the potential to improve the efficacy of current Hg fluorescent lamps and/or Xe lamps by reducing the Stokes shift energy loss after VUV excitation (λexc=185 nm for Hg lamps or 147 nm and 172 nm for Xe lamps provided the emission color of the phosphor matches the eye sensitivity. The current technology in QSPs and their potential limitations will be discussed in this paper. At GE-CRD, we have discovered and developed QSPs that meet the requirements for use in current Hg based fluorescent lamps. The steady state and time resolved optical properties of one of these phosphors, SrAl12O19:Pr3+,Mg2+, has been measured to estimate the maximum quantum efficiency and onset of concentration quenching in this phosphor. The maximum quantum efficiency for SrAl12O19:Pr3+,Mg2+ has been calculated to be ∼125-135% for 185 nm excitation with an upper bound on the Pr3+ doping level of ∼1%.</jats:p