Photoluminescence of bridged silsesquioxanes containing urea groups: doping with Safranine-O to generate red light emission

M. L. GÓMEZ; D. P. FASCE; R. J. J. WILLIAMS; H. A. MONTEJANO; C. M. PREVITALI

JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS

Wiley

Lugar: New York; Año: 2008 vol. 46 p. 289 - 296

0887-6266

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-US;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Bridged polysilsesquioxanes containing urea groups (ureasils) exhibit a broad photoluminescent emission in the visible spectrum. For a particular bridged polysilsesquioxane synthesized by the hydrolytic condensation of a precursor prepared by reaction of 4,4’ [1,3 phenylenebis-(1-methylethylidene)]bis(aniline) (BSA) with 3-(isocyanatepropyl)triethoxysilane (IPTES), we show that the broad photoluminescent band could be transformed into a relatively narrow emission band located in the red region of the spectra, by doping with Safranine-O. The spectral overlap between the host emission and the dye absorption generated an efficient energy transfer process (antenna effect). Absorption, emission and triplet-triplet absorption spectra revealed an efficient dispersion of the dye in the ureasil as well as the presence of strong host-guest specific interactions.