| Autor: |
Gupta, Santosh K., Bhide, Madhusudan Krishnadas, Godbole, Shrikant Vasant, Natarajan, Venkataraman, Ballato, John |
| Předmět: |
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| Zdroj: |
Journal of the American Ceramic Society; Nov2014, Vol. 97 Issue 11, p3694-3701, 8p, 2 Black and White Photographs, 2 Charts, 10 Graphs |
| Abstrakt: |
ThO2: Eu3+ nanoparticles were synthesized at 300°C by combustion route using urea as a fuel and characterized by thermogravimetric/differential thermal analysis, X-ray diffraction, transmission electron microscopy, and photoluminescence techniques. To investigate the effect of annealing temperature, as synthesized powder were heated further at 500°C, 700°C, and 900°C. It was observed that extent of asymmetry around Eu3+ at 700°C/900°C is very high as compared to as-prepared or 500°C annealed sample. Based on the time resolved emission spectroscopic investigations, it was inferred that two different types of Eu3+ ions were present in the ThO2 nanoparticles. In ThO2 structure, Eu3+ ions occupy two sites; cubic (Oh) and noncubic (2v) as can be confirmed from our emission studies. Short-lived species T1 (~1.3-3.4 ms) predominates at higher annealing temperature arises because of Eu3+ ions occupying noncubic (2v) sites without inversion symmetry, whereas long-lived species T2 (~4.6-6.6 ms) can be ascribed to Eu3+ ions occupying cubic sites (Oh) with inversion symmetry. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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