Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5160952 | Journal of Molecular Structure | 2016 | 29 Pages |
Abstract
The xerogels and sol-gel powders with different quantitative composition have been studied based on excitation and emission measurements as well as luminescence decay analysis. The structure of prepared silica sol-gel materials was examined using FT-IR spectroscopy technique. The photoluminescence spectra of Eu3+ ions were registered upon two different excitation wavelengths related to direct excitation of Eu3+ ions (λexc = 393 nm) and indirect excitation through energy transfer process from Gd3+ to Eu3+ (λexc = 273 nm). Upon direct excitation of Eu3+ (7F0 â 5L6 transition) the characteristic emission bands assigned to the 5D0 â 7FJ(0-4) electronic transitions were observed. Also, it was found that enhanced luminescence of Eu3+ is a result of change the excitation parameter through energy transfer phenomenon (8S7/2 â 6IJ transition of Gd3+) and occurred in both xerogels and powder samples. In this way, a UV photon absorbed by Gd3+ is converted into visible light emitted by Eu3+ ions. Obtained results clearly indicated that high concentration of Gd3+ ions in powders led to particularly strong enhance the emission in red spectral range and allowed for more than 12-times prolongation of luminescence lifetime for the 5D0 excited state of Eu3+ compared to silica xerogel samples. The values of energy transfer efficiency were also estimated based on luminescence decay times of the 6P7/2 state of Gd3+ ions.
Related Topics
Physical Sciences and Engineering
Chemistry
Organic Chemistry
Authors
Natalia Pawlik, Barbara Szpikowska-Sroka, Andrzej S. Swinarew, Marta ÅÄżniak, Wojciech A. Pisarski,