Preparation, crystal structure and photoluminescence properties of Ce3+ activated Ba3Y1−yLuyAl2O7.5 phosphors for near-UV LEDs

Abstract

A series of novel blue-green broadband emitting phosphors Ba3Y1−yLuyAl2O7.5: Ce3+ (0⩽y⩽0.5) were synthesized via the solid state reaction. The crystal structure and the photoluminescence properties were investigated for the application in white light-emitting diodes. The phosphors have two Ba2+ sites and one Y(Lu)3+ site with different coordination environment. These phosphors show the good absorption ranging from the ultraviolet to the blue region, the emission spectra contain both blue and green compositions, and the peaks can shift from 478nm to 493nm by changing the doped Lu3+ concentration, the mechanisms and reasons of the changes of the PL/PLE spectra, fluorescence decay curves and thermal quenching properties have also been studied in detail. The critical distance for Ce3+ ions in the Ba3YAl2O7.5 host was calculated to be 23.85Å and the energy transfer mechanism occurs among the nearest-neighbor ions. The above results indicate that Ba3Y1−yLuyAl2O7.5: Ce3+ is a good candidate as the blue-green component for near-UV LEDs.