Effects of Li + Codoping on the Optical Properties of SrAl 2 O 4 Long Afterglow Ceramic Phosphors

Abstract

Rare-earths codoped long afterglow strontium aluminate phosphors with high brightness were synthesized via a facile combustion synthesis method using urea as a fuel. The resulted phosphor particles were analyzed by using X-ray diffraction and field emission scanning electron microscope, whereas their optical properties were monitored by photoluminescence spectroscopy. The prepared SrAl 2 O 4 :Eu 2+ , Dy 3+ , Li + samples showed a broad green-yellowish emission, peaking at 512 nm when excited by 348 nm. Compared to traditional SrAl 2 O 4 :Eu 2+ , Dy 3+ phosphor, the initial luminescence brightness of SrAl 2 O 4 :Eu 2+ , Dy 3+ , codoped with Li + improved from 1.89 cd/m 2 to 2.71 cd/m 2 and the afterglow decay time was prolonged from 103 to 121 min. The possible mechanism of SrAl 2 O 4 :Eu 2+ , Dy 3+ , Li + phosphorescence enhancement has been discussed.