Tunable emission from blue to white light in single-phase Na0.34Ca(0.66-x-y)Al1.66Si2.34O8:xEu(2+),yMn(2+) (x=0.07) phosphor for white-light UV LEDs

Abstract

A series of single-phased emission-tunable Na0.34Ca0.66Al1.66Si2.34O8:Eu2+,Mn2+ phosphors were successfully synthesized by a wet-chemical synthesis method. Photoluminescence excitation (PLE) spectra indicate that the phosphor can be efficiently excited by UV radiation from 250 to 420 nm. Also, NCASO: Eu2+,Mn2+ phosphor exhibit a broad blue emission band at 440 nm and an orange emission band at 570 nm, which originate from Eu2+ and Mn2+ ions, respectively. Therefore, overall emission color can be tuned from blue to white by increasing the concentration of Mn2+ ions in the host lattice utilizing energy transfer from Eu2+ to Mn2+ ions. This energy transfer phenomenon was demonstrated to be a resonant type through dipole-dipole interaction determined with the help of PL spectra, decay time measurement, and energy transfer efficiency of the phosphor. These results indicate that NCASO:Eu2+,Mn2+ can be a promising single-phased white-emitting phosphor for white-light UV LEDs. (C) 2013 Optical Society of America