UV or blue light excited red persistent perovskite phosphor with millisecond lifetime for use in AC‐LEDs

Energy storage phosphors with millisecond period afterglow that compensate for the diming time of alternating current light‐emitting diodes (AC‐LEDs) have promising application. To obtain a persistent luminescence (PersL) white colour in AC‐LEDs, we focussed on a red afterglow with short period phosphorescence. Ca 4 Ti 3 O 10 forms a type of perovskite‐related Ruddlesden–Popper phase structure. Doping Pr 3+ ions into Ca 4 Ti 3 O 10 , an ideal red PersL was obtained. X‐ray diffraction and element analysis demonstrated that our target samples were crystallized well. Steady‐state and afterglow luminescence properties were investigated in detail. Notably, the PersL intensity was dependent on various excitation wavelengths. By measuring three‐dimensional thermoluminescence spectra, we found that the trap depths showed a continuous distribution and that the shallowest trap contributed to the millisecond afterglow. Two PersL mechanism models were used to elucidate the electron charging and de‐trapping processes under UV or blue light activation.