Structure-photoluminescence relationship in Eu(III) beta-diketonate-based organic-inorganic hybrids. Influence of the synthesis method: carboxylic acid solvolysis versus conventional hydrolysis
authors Fu, LS; Ferreira, RAS; Silva, NJO; Fernandes, JA; Ribeiro-Claro, P; Goncalves, IS; Bermudez, VD; Carlos, LD
nationality International
journal JOURNAL OF MATERIALS CHEMISTRY
keywords WHITE-LIGHT EMISSION; FULL-COLOR PHOSPHORS; GEL-DERIVED SILICA; RARE-EARTH IONS; IN-SITU; PHOTOPHYSICAL PROPERTIES; LUMINESCENCE BEHAVIOR; QUANTUM YIELDS; EU3+ IONS; COMPLEXES
abstract Organic-inorganic hybrids incorporating Eu(nta)3(.)bpy (where nta and bpy stand for 1-(2-naphthyl)- 4,4,4-trifluoro-1,3-butanedionate and 2,2'-bipyridine, respectively) were prepared either by acetic acid solvolysis or a conventional hydrolysis sol - gel route. The host framework of these materials, classed as di-ureasil, consists of a siliceous network grafted, through urea cross-linkages, to both ends of poly(ethylene oxide) chains. The resulting Eu(III)-based di-ureasils were investigated by small angle X-ray scattering, X-ray diffraction, Fourier transform mid-infrared spectroscopy, Si-29 and C-13 nuclear magnetic resonance, and photoluminescence spectroscopy, with particular attention paid to the effect of the adopted synthesis strategy on the relationship between structure and emission properties. The dimensions and the degree of condensation of the siloxane nanodomains depend noticeably on the synthesis route and the overall emission quantum yield decreases from 15 (conventional hydrolysis) to 6% (solvolysis route). The broad white-light emission typical of the di-ureasil host was not detected here suggesting, therefore, the activation of energy transfer channels between the hybrid host's emitting centres and the Eu(III) ions. As the first coordination shell of Eu(III) is essentially independent of the synthesis method employed, the significant decrease in the emission quantum yield for the di-ureasil prepared by acetic acid solvolysis might be explained by the interaction between the hybrid emitting centres and the nta ligand levels, favouring a larger non-radiative transition probability.
publisher ROYAL SOC CHEMISTRY
issn 0959-9428
year published 2005
volume 15
issue 30
beginning page 3117
ending page 3125
digital object identifier (doi) 10.1039/b503844h
web of science category Chemistry, Physical; Materials Science, Multidisciplinary
subject category Chemistry; Materials Science
unique article identifier WOS:000230776100008

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