Botterman, Jonas

Joos, Jonas

Poelman, Dirk

Smet, Philippe

English

Ghent University Academic Bibliography

Temperature and wavelength dependent trap filling in SrAl2O4:Eu,Dy  Jonas Botterman, Jonas J. Joos, Dirk Poelman, Philippe F. Smet LumiLab, Dpt. of Solid State Sciences, Ghent University, Krijgslaan 281-S1, 9000 Gent, Belgium Center for Nano- and Biophotonics (NB Photonics), Ghent University, Gent, Belgium Email: jonas.botterman@UGent.be    Persistent luminescent phosphors are photoluminescent materials that keep emitting light for minutes or hours after the termination of the excitation. This peculiar phenomenon is the result of at least two kinds of active centers in the phosphor, a luminescence center and a trapping center, and of the temperature dependent exchange of charge carriers between these centers [1].   Strontium aluminate doped with europium and dysprosium (SrAl2O4:Eu,Dy) is one of the most widely used persistent luminescent phosphors. At room temperature, it features a broad green emission band and bright long-lasting afterglow. At low temperatures (< 250 K) a second, blue emission band becomes visible (Fig. 1) for which the origin is still subject of debate.   To investigate the origin of this blue emission band and its role in the persistent luminescence trap filling process (Fig. 2), we performed a dedicated study on SrAl2O4:Eu,Dy in which we combined temperature dependent charging and afterglow measurements with thermoluminescence measurements, using different excitation wavelengths.     [1] K. Van den Eeckhout, P.F. Smet, D. Poelman, Materials 2010, 3, 2536-2566. Fig. 1: Emission spectrum (solid line, λex = 370 nm) and excitation spectra (blue dotted line, λem = 445 nm and green dashed line, λem = 520 nm) of SrAl2O4:Eu,Dy at 10 K. Fig. 2: Amount of filled traps after excitation during 15 min at different temperatures. (red squares, λex = 370 nm and blue circles, λex = 435 nm) 

Temperature and wavelength dependent trap filling in SrAl2O4:Eu,Dy

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Temperature and wavelength dependent trap filling in SrAl2O4:Eu,Dy

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Ghent University Academic Bibliography