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/m2). 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.

Graphical AbstractLLP spectra of SASO:Eu2+,RE3+ (RE=Ho, Gd, Dy and Pr) measured 3 min after the excitation source was switched off (Inset: CIE1931 Chromaticity Diagram)Figure optionsDownload as PowerPoint slide