Photoluminescence and quantum yields of organic/inorganic hybrids prepared through formic acid 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, 29Si and cross-polarization 13C 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 ∼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.