Luminescent properties of blue long-lasting phosphorescence phosphors Sr6Al18Si2O37:Eu2+,RE3+

A series of novel blue long-lasting phosphorescence phosphors Sr6Al18Si2O37:Eu2+,RE3+ (RE3+= Ho3+, Gd3+, Dy3+ and Pr3+) were prepared by the conventional high-temperature solid-state reaction in a reductive atmosphere. Their properties were systematically investigated utilizing X-ray diffraction (XRD), photoluminescence, phosphorescence and thermoluminescence (TL) spectra. The phosphors emitted blue light that was related to the emission of Eu2+ due to 5d-4f transition. Bright blue long-lasting phosphorescence (LLP) could be observed after the excitation source was switched off. For the optimized sample, the blue long-lasting phosphorescence could last for nearly 4 h in the light perception of the dark-adapted human eye (0.32 mcd/m(2)). The effects of RE3+ ions on phosphorescence properties of the phosphors were studied, and the results showed that the co-doping of RE3+ ions greatly enhanced the intensity of the peak around 315 K which was related to the long lasting phosphorescence of the phosphors at room temperature and consequently improved the performance of the blue phosphorescence such as intensity and persistent time.