Near-infrared long persistent luminescence of Er3+ in garnet for the third bio-imaging window

By utilizing efficient persistent energy transfer from Ce³⁺ to Er³⁺, we have successfully developed a novel garnet persistent phosphor of Y₃Al₂Ga₃O₁₂ doped with Er³⁺, Ce³⁺, Cr³⁺ ions (YAGG:Er–Ce–Cr) exhibiting long (>10 h) near-infrared (NIR) persistent luminescence (PersL) in the broad range from 1450 nm to 1670 nm due to the typical Er³⁺:⁴I_13/2 → ⁴I_15/2 transition in garnet.