Photoluminescence and quantum yields of organic/inorganic hybrids prepared through formic solvolysis

Three undoped di-urea cross-linked poly(oxyethylene) (POE)/siloxane hybrid matrices, classed as di-ureasils, incorporating POE segments with different lengths were prepared through the carboxylic acid solvolysis sol-gel method using formic acid. The resulting hybrids were characterized by X-ray diffraction, Fourier transform mid-infrared spectroscopy, Si-29 and cross-polarization C-13 magic-angle spinning nuclear magnetic resonance and photoluminescence spectroscopy. The hybrids' structure is essentially independent of the polymer chain length and the materials are room temperature white-light emitters with emission quantum yields of similar to 10 +/- 1% and lifetime average values between 2 and 4 ns. For the di-ureasil host with short polymer chains the solvolysis method favours the increase of the PL quantum yields relatively to conventional sol-gel route. (c) 2007 Elsevier B.V. All rights reserved.