Enhancing the white light emission of SrAl2O4:Ce3+ phosphors by codoping with Li+ ions

The structural, morphological and luminescent properties of SrAl2O4:Ce3+(SAO:Ce) phosphors doped with Ce3+ concentrations from 0.5 at up to 7 at% and synthesized by combustion synthesis are reported. The morphology of the particles changes from coalesced grains (with average size of 121 nm) for a cerium concentration of 0.5 at% to needle-like shape when the cerium concentration is above 1% (with an average length of 1-2 mu m). XRD patterns also show a change in the crystalline structure from monoclinic to hexagonal when the Li ion is introduced to improve the luminescent properties. The sample doped with 0.5 at% of Ce3+ presents the highest white luminescence. When this sample was codoped with 0.2 at% of Li+, there was an increase of 100% in the white light emission. The luminance values of the samples with and without Li+, under UV-LED excitation (365 nm commercial Star LED) were 1630 cd/m(2) and 3760 cd/m(2), respectively. That is, the luminance enhancement achieved by lithium co-doping was 130%. Thus, our results indicate that Li codoped SrAl2O4:Ce3+ phosphors could be useful for applications in displays and solid state lighting. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.