| Autor: |
Yu-Feng Lin, Yu-Chun Li, Yu-Chung Chen, Bin-Siang Tsai, Yen-Hwei Chang |
| Rok vydání: |
2006 |
| Předmět: |
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| Zdroj: |
Journal of Alloys and Compounds. 416:199-205 |
| ISSN: |
0925-8388 |
| DOI: |
10.1016/j.jallcom.2005.08.025 |
| Popis: |
The photoluminescence properties of Eu-doped Sr 2 La 8 (GeO 4 ) 6 O 2 were investigated by measuring emission and excitation spectra, and decay curves. The Eu 3+ ions were found to occupy two cationic sites labeled La(2) and Sr(1). The dominant sites La(2) occupied by Eu 3+ ions shows strong red emission ( 5 D 0 → 7 F 2 transition) at 613 nm. The Eu 3+ ions incorporated into the subordinate sites Sr(1) produces strong orange emission ( 5 D 0 → 7 F 1 transition) at 589 nm. This would be responsible for the charge-compensating mechanism, in which inversion symmetry is evident around the europium ions. The concentration quenching behaviors of excitation under CTS and intra-4f energy levels are different. The emission intensity decreases at the onset of about 15 mol% Eu 3+ concentration under the excitation at CTS, and the saturation of emission intensity excited by intra-4f transitions occurs at a concentration of 50 mol% Eu 3+ . The maximum photoluminescence intensity of excited at intra-4f transitions is about a factor of 10 times brighter than that excited at CTS. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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Full Text from ScienceDirect