UV–VUV spectroscopy of rare earth doped persistent luminescence materials

✍ Scribed by J. Hassinen; J. Hölsä; J. Niittykoski; T. Laamanen; M. Lastusaari; M. Malkamäki; P. Novák

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 374 KB
• Volume: 31
• Category: Article
• ISSN: 0925-3467
• DOI: 10.1016/j.optmat.2009.01.016

✦ Synopsis

The electronic and defect energy level structure of polycrystalline SrAl 2 O 4 :Eu 2+ ,R 3+ persistent luminescence materials were studied with thermoluminescence and UV-VUV synchrotron radiation emission and excitation spectroscopy. Theoretical calculations using the density functional theory (DFT) were carried out simultaneously with the experimental work. The experimental band gap energy (E g ) value of 6.6 eV agrees very well with the DFT value of 6.4 eV. The 4f 7 ? 4f 6 5d 1 excitation bands of Eu 2+ were found rather similar irrespective of the R 3+ co-dopant. The trap level energy distribution depended strongly on the R 3+ co-dopant except for the shallowest trap energy above the room temperature remaining the same, however. The different processes in the mechanism of persistent luminescence from SrAl 2 O 4 :Eu 2+ ,R 3+ was constructed and discussed.