Sr9R2−xEuxW4O24 (R=Gd and Y) red phosphor for near-UV and blue InGaN-based white LEDs

Eu3+-activated phosphors, Sr9R2−xEuxW4O24 (R=Gd and Y ), were prepared by the conventional solid-state reaction method and their photoluminescent properties were studied. The phosphors show intense red emission under 395 and 465 nm light excitation, which is matched with the light-emitting wavelength of a near-UV-emitting and a blue-emitting InGaN chips, respectively. Bright red-light-emitting diodes (LEDs) and white-light-emitting diodes (WLEDs) were fabricated by coating Sr9Y 0.4Eu1.6W4O24 phosphor onto ∼395 nm-emitting InGaN chips and ∼460 nm blue-emitting InGaN chips, respectively. The good performances of the LEDs demonstrate that the tungstates are suitable for application of near-UV and blue InGaN-based WLEDs.