Silica glasses singly doped and co-doped with Cr ions and Dy ions have been prepared by sol/gel method and their
photoluminescence (PL) properties have been studied. The emission spectrum of Dy singly doped sample shows a band around 450
nm with a shoulder band around 480 nm, Cr singly doped sample consists of three bands around 450, 530 and 620 nm, and Cr, Dy
co-doped samples show two bands around 450 and 530 nm. The relative PL intensity of the green emission at 530 nm in co-doped
samples increases greatly compared with the singly doped. These two bands at 450 and 530 nm are respectively assigned to the
defects in silica network and a complex luminescence centers associated with Cr ions. The quenching effect of metal ions and energy
transfer process could be responsible for the change of PL properties in the co-doped samples.
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