Mn2+ activated red long persistent phosphors in BaMg2Si2O7

Novel red long persistent phosphors of BaMg2Si2O7:Mn2+, Eu2+, Dy3+ have been synthesized at high temperature and weak reductive atmosphere. There are a deep blue emission with peak wavelength of 400 nm and a broader emission band centered at 680 nm when excited by 340 nm. The broad emission band is attributed to the spin-forbidden transitions of the d-orbital electrons associated with the Mn2+ ions (4T1(4G)-6A1(6S)). The excitation and emission spectra of the samples with different dopants and doping concentrations show that the Mn2+ emission is dominantly due to the persistent energy transfer from Eu2+. Red long persistent phosphors have been observed in the system for over 2 h