Luminescent coatings from bipyridine-based bridged silsesquioxanes containing Eu3+ and Tb3+ salts
authors Graffion, J; Cojocariu, AM; Cattoen, X; Ferreira, RAS; Fernandes, VR; Andre, PS; Carlos, LD; Man, MWC; Bartlett, JR
nationality International
journal JOURNAL OF MATERIALS CHEMISTRY
keywords SOL-GEL APPROACH; THIN-FILMS; HYBRID MATERIALS; POLYSILSESQUIOXANES; PHOTOLUMINESCENCE; POLYCONDENSATION; HYDROLYSIS; PRECURSORS; EFFICIENT; EMISSION
abstract The sol-gel fabrication of bridged silsesquioxane thin films containing trivalent lanthanide ions (Ln(3+)) has been achieved from a 4,4'-diureido-2,2'-bipyridine bridged organosilane (P4) in the presence of Eu3+ or Tb3+ salts. Crack-and defect-free thin films (similar to 50 nm) of optical quality were successfully deposited on glass substrates by spin-coating after optimizing the spinning rate and solvent system. Ellipsometry investigations revealed a significant decrease in the refractive index of the films with ageing of the corresponding precursor sols. In contrast, the photoluminescence properties of the films are independent of precursor ageing time, although significant differences are observed with respect to the corresponding bulk materials. Compared to the bulk materials, the films exhibit a significant blue-shift of the excitation spectra and an increase of the excited state lifetime. The optical conversion efficiencies (eta(opt)) of the F4-Eu and F4-Tb-based collectors were also determined and potential applications of the coatings in such areas as luminescent solar concentrators are discussed.
publisher ROYAL SOC CHEMISTRY
issn 0959-9428
year published 2012
volume 22
issue 26
beginning page 13279
ending page 13285
digital object identifier (doi) 10.1039/c2jm31289a
web of science category Chemistry, Physical; Materials Science, Multidisciplinary
subject category Chemistry; Materials Science
unique article identifier WOS:000305242300044

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