Luminescence properties of a new bluish green long-lasting phosphorescence phosphor Ca9Bi(PO4)7:Eu2+,Dy3+

• Bluish green long-lasting phosphorescence Ca9Bi(PO4)7:Eu2+,Dy3+ phosphor was synthesized for the first time.
• The luminescence and phosphorescence properties of Ca9Bi(PO4)7:Eu2+,Dy3+ were systematically studied.
• The corresponding afterglow mechanism of this phosphor was discussed.

A new long-lasting phosphorescence phosphor Ca9Bi(PO4)7:Eu2+,Dy3+ was synthesized by solid state reaction and its long-lasting phosphorescence properties were investigated for the first time. The X-ray powder diffraction, photoluminescence, long-lasting phosphorescence spectra, decay curves and thermoluminescence curves were measured. The Ca9Bi(PO4)7:Eu2+,Dy3+ phosphor exhibits an asymmetric emission centered at 475 nm, which can be ascribed to the 4f65d1–4f7 electronic transition of Eu2+. For the optimized sample, the bright bluish green long-lasting phosphorescence could be observed for 5 h by naked eyes after the excitation source was removed. The long-lasting phosphorescence spectra show that the co-doping of Dy3+ ions greatly enhance the intensity of the long-lasting phosphorescence. Meanwhile, the long-lasting phosphorescence mechanism of this phosphor was discussed. Based on our study, Dy3+ ions are suggested to increase the density of electron or hole traps so as to improve the performance of the bluish green phosphorescence of Eu2+, including the intensity and persistent time.