Su Qiang

Long-lasting phosphorescence study on Y3Al5O12 doped with different concentrations of Ce3+

Abstract Long-lasting phosphorescence (LLP) was observed in Ce-doped Y 3 Al 5 O 12 phosphors synthesized in reducing atmosphere. The characteristic emission of the 2 D- 2 F 5/2 and 2 D- 2 F 7/2 transition of Ce 3+ in photoluminescence (PL) and LLP spectra was studied. It was interesting that the ratio between the peak areas of 2 D- 2 F 5/2 and 2 D- 2 F 7/2 transitions in the PL spectrum was different from the ratio of that in LLP emission spectrum. And the ratios had different change regularities with increased Ce 3+ concentration. The possible reason was attributed to the defect in the YAG host, which was affected by increasing the Ce 3+ concentration. There were indications that the defect in the Ce 3+ -doped YAG samples was strongly associated with oxygen vacancy. And the defect levels were studied through thermoluminescence (TL) experiment. The results showed that the trap depth was between 0.6 and 0.65 eV, and the kinetic order of the LLP was 2.

Luminescence properties of a new yellow long-lasting phosphorescence phosphor NaAlSiO4:Eu2+,Ho3+

Abstract A new aluminosilicate long-lasting phosphor with composition of NaAlSiO 4 :Eu 2+ ,Ho 3+ was synthesized and investigated. Under UV light excitation, the phosphor emitted yellow light corresponding to the characteristic emission of Eu 2+ due to 5d-4f transition. Bright yellow phosphorescence sustaining for more than 30 min was observed after ceasing the excitation. The phosphorescence intensity decay obeyed a t −1 decay law, indicating a tunneling electron-hole recombination process in the phosphor. Four peaks appeared in the thermoluminescence curve and the ones at 322 and 370 K were thought to account for the long lasting phosphorescence at room temperature. The Ho 3+ ion incorporated into the phosphor did not give any light but dramatically increased the intensities of both photoluminescence and phosphorescence via promoting defect levels in the phosphor.

Long Lasting Phosphorescence in Eu2+ and Ce3+ Co-Doped Strontium Borate Glasses

Long lasting phosphorescence (LLP) was observed in Eu2+, Ce3+ co-doped strontium borate glasses prepared under the reducing atmosphere due to the emission of both Eu2+ and Ce3+. The methods of photoluminescence, thermoluminescence and phosphorescence were used to study the samples, and possible mechanism was suggested. The co-doping of Ce3+ ions poisoned the phosphorescence emission of Eu2+ because of the competition to obtain the trapped electron. The phosphorescence of Ce3+ in the sample decays more quickly than that of Eu2+, which is suggested for the reason that the emission energy of Ce3+ is higher or the distance between Ce3+ and electron traps of the glasses is longer.