Temperature dependence of persistent phosphorescence in Eu2+-doped Ba3SiO5

• Persistent phosphorescence occurs through tunneling electron–hole recombination.
• Recombination rate depends on thermally activate energy of trapped electrons.
• Deexcitation occurs through thermally multiphonon-assisted relaxation to the Eu2+ ground state.

Temperature dependence of decay curves of persistent phosphorescence in Eu2+-doped Ba3SiO5 crystals indicates that there are, at least, three electron–hole recombination centers. The decay curve from the dominant center is represented by I(t) = (A/t)( exp(−t/τ1) − exp(−t/τ0)) or I(t) = A/tn (n > 1) below or above 360 K, respectively. The integrated intensities of the decay curves decrease drastically in increasing temperature above 360 K. As such temperature behavior is very similar to that of the intrinsic Eu2+ luminescence with short decay times of less than 2.7 μs in Ba3SiO5, the deexcitation occurs through thermally multi-phonon assisted nonradiative relaxation to the ground state of Eu2+ in Ba3SiO5.