Carlos, Luís D.Ferreira, Rute A. SáZéa Bermudez, Verónica deBueno, Luciano A. [UNESP]Molina, Celso [UNESP]Messaddeq, Younes [UNESP]Ribeiro, Sidney José Lima [UNESP]2014-05-202014-05-202001-08-01Química Nova. Sociedade Brasileira de Química, v. 24, n. 4, p. 453-459, 2001.0100-4042http://hdl.handle.net/11449/27574Eu3+ luminescence and EXAFS (Extended X-ray Absorption Fine Structure) results are presented for organic-inorganic hybrid gel hosts composed of a siliceous network to which small chains of oxyethylene units are covalently grafted by means of urea bridges. Coordination numbers for Eu3+ ions range from 12.8 to 9.7 with increasing Eu3+ concentration while the Eu3+-first neighbours mean distance is found to be constant at 2.48-2.49 Å in the same concentration range. Emission spectra display a broad band in the green/blue spectral region superposed to narrow lines appearing in the yellow/red region in such a way that for the eyes emission appears white. The broad band is assigned to intrinsic NH groups emission and also to electron-hole recombination in the nanosised siliceous domains. The narrow lines are assigned to intra-4f6, 5D0->7F0-4 Eu3+ transitions and from the energy position of the 7F0-4 levels a mean distance could be calculated for the Eu3+-first neighbours. The calculated results are in good agreement with the experimental ones obtained from EXAFS analysis.453-459pororganic-inorganic hybridsluminescenceEXAFSArtigo10.1590/S0100-40422001000400005S0100-40422001000400005Acesso abertoS0100-40422001000400005.pdf299850384191781564460474630346540000-0003-3286-9440