In the present work the effects produced by Eu3+ incorporation into sol-gel silica (doping level range: 0.001-10 mol%) are monitored by means of Fourier transform vibrational spectroscopy in the wave number range 200-3000 cm(-1). Complementary microreflectance, TEM, and Raman spectroscopy measurements are also performed. By increasing the Eu3+ concentration up to 3 mol%, the intrinsic absorption/reflectance bands related to vibrational modes of O-Si-O groups are gradually modified for what concerns the peak position and intensity, and absorption shoulders attributable to the Eu3+ doping appear. At 10 mol% sharp, new, Eu-related peaks grow at the expenses of the intrinsic absorptions. The results can be explained in terms of Eu-rich cluster formation, as also supported by Raman spectra analysis and TEM images. The cluster sizes increase by increasing the Eu3+ concentration. Their structure, in which tetrahedral (SiO4)(4-) groups are still present, remains amorphous for Eu3+ concentration up to 3 mol%, turning into a nearly ordered arrangement for the higher one. The spectral analysis in the regions of the weaker absorptions due to combination and overtone modes further supports the results and allows to associate the fundamental and overtone frequencies for two modes in Eu3+ 10 mol% doped silica. In the framework of the Morse anharmonic oscillator model, the related anharmonicity parameters and binding energies were calculated and found close to those reported for (SiO4)(4-) groups.

Buffagni, E., Baraldi, A., Capelletti, R., Mazzera, M., Fasoli, M., Gemmi, M., et al. (2010). Vibrational spectroscopy of silica glasses doped with Eu3+ ions. In IOP Conference Series: Materials Science and Engineering. IOP PUBLISHING LTD [10.1088/1757-899X/15/1/012033].

Vibrational spectroscopy of silica glasses doped with Eu3+ ions

FASOLI, MAURO;LAURIA, ALESSANDRO;VEDDA, ANNA GRAZIELLA
2010

Abstract

In the present work the effects produced by Eu3+ incorporation into sol-gel silica (doping level range: 0.001-10 mol%) are monitored by means of Fourier transform vibrational spectroscopy in the wave number range 200-3000 cm(-1). Complementary microreflectance, TEM, and Raman spectroscopy measurements are also performed. By increasing the Eu3+ concentration up to 3 mol%, the intrinsic absorption/reflectance bands related to vibrational modes of O-Si-O groups are gradually modified for what concerns the peak position and intensity, and absorption shoulders attributable to the Eu3+ doping appear. At 10 mol% sharp, new, Eu-related peaks grow at the expenses of the intrinsic absorptions. The results can be explained in terms of Eu-rich cluster formation, as also supported by Raman spectra analysis and TEM images. The cluster sizes increase by increasing the Eu3+ concentration. Their structure, in which tetrahedral (SiO4)(4-) groups are still present, remains amorphous for Eu3+ concentration up to 3 mol%, turning into a nearly ordered arrangement for the higher one. The spectral analysis in the regions of the weaker absorptions due to combination and overtone modes further supports the results and allows to associate the fundamental and overtone frequencies for two modes in Eu3+ 10 mol% doped silica. In the framework of the Morse anharmonic oscillator model, the related anharmonicity parameters and binding energies were calculated and found close to those reported for (SiO4)(4-) groups.
paper
vibrational spectroscopy;silica; rare-earth ions
English
11th Europhysical Conference on Defects in Insulating Materials (EURODIM 2010)
2010
IOP Conference Series: Materials Science and Engineering
2010
15
012033
none
Buffagni, E., Baraldi, A., Capelletti, R., Mazzera, M., Fasoli, M., Gemmi, M., et al. (2010). Vibrational spectroscopy of silica glasses doped with Eu3+ ions. In IOP Conference Series: Materials Science and Engineering. IOP PUBLISHING LTD [10.1088/1757-899X/15/1/012033].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/24617
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