Persistent luminescence in rare-earth codoped image

The luminescence properties of image (with image, Sm, Dy, Ho or Tm) are reported. image without codopants shows a relatively weak afterglow. image,Tm shows the highest persistent emission intensity, with an orange emission color due to a broad emission band peaking at 620 nm. The persistence emission spectrum is red-shifted by about 10 nm compared to the steady state photoluminescence. Based on thermoluminescence measurements, it is shown that the addition of Nd, Dy and Ho to image introduces trap states which are too shallow for considerable enhancement of the persistent luminescence. The persistent luminescence in image is efficiently excited in the visible part of the spectrum.