Preparation and Photoluminescence Properties of SrAl2O4:Eu2+,RE3+ Green Nanophosphors for Display Device Applications

An efficient rapid gel combustion process was used to prepare divalent-europium-doped strontium aluminate (SrAl2O4:Eu2+/Eu2+,Dy3+/Eu2+,Dy3+,Nd3+) nanophosphors in the presence of boron flux in air. The prepared nanophosphors emitted green light at 507 nm upon excitation at 360 nm. The emission of green light was observed due to the 4f (6)5d (1) -> 4f (7) transition of Eu2+ ions. The absence of the characteristic sharp emission peak at 612 nm for Eu3+ (D-5(0) -> F-7(2)) indicates that efficient reduction of Eu3+ to Eu2+ occurred in the presence of the boron flux (H3BO3) as reducing agent. The x-ray diffraction pattern suggested monoclinic crystallinity, while transmission electron microscopy revealed the average size of the prepared materials to be between 20 nm and 50 nm. Coactivators in the lattices such as Dy3+ alone or Dy3+ with Nd3+ produced long persistence and enhancement of the optoelectronic properties of the prepared materials.