A novel red long persistent luminescent Ca2Ga2GeO7:Pr3+ phosphor is developed.
Pr3+ replaces disordered Ca2+ sites, leading to efficient persistent luminescence.
Persistent luminescence is visible for 5 h by dark-adapted vision in dark.
Important roles of retrapping and tunneling on decay behaviors are revealed.
Threshold depth is firstly defined for evaluation of retrapping and tunneling.