Enhancement of long-lived luminescence in nanophosphors by surface defect passivation

Herein, we found that surface defects quench persistent luminescence in nanophosphors. Passivation of surface defects by thermal treatment or surface coating can effectively enhance the intensity and prolong the decay time of persistent luminescence. The surface passivated persistent nanophosphors are promising in autofluorescence-free bioimaging and time-gated steganography.