Transparent Polysilsesquioxane Films Obtained from Bridged Ureasil Precursors: Tunable Photoluminescence Emission in the Visible Region and Filtering of UV-radiation.

M. L. GOMEZ (*); D. P. FASCE; R. J. J. WILLIAMS (*); C- M. PREVITALI; H. A. MONTEJANO

MACROMOLECULAR MATERIALS AND ENGINEERING (PRINT)

WILEY-V C H VERLAG GMBH

Año: 2010 vol. 295 p. 1042 - 1048

1438-7492

Bridged ureasil precursors were synthesized by the reaction of either ethylenediamine (1 mol)or m-xylylenediamine (1 mol) with isocyanatepropyltriethoxysilane (2 mol). Transparent polysilsesquioxane films were obtained by the hydrolytic condensation of the pure precursors or their co-condensation in a 50:50 molar ratio. Films based on pure ureasil precursors showed a blue photoluminescent emission band assigned to the photoinduced proton-transfer among H-bonded urea groups and the subsequent radiative recombination of ionized groups. Films synthesized by the co-condensation of both precursors exhibited a significant red-shift of their absorption, excitation, and emission spectra, associated to de-localization of H-bonds, and a high absorption of UV-radiation.