Synthesis and luminescence behavior of inorganic-organic hybrid materials covalently bound with pyran-containing dyes

摘要

A DCM derivative, namely 4-Dicyanomethy-lene-2-methy 1-6- {[4'-(N-hydroxyethyl-N-methyl)amino] styryl}-4H-pyran (DCMH), has been synthesized and covalently incorporated into the inorganic silica network as pendants via a sol-gel process. Molecular structures of the resultants are confirmed by elemental analysis,~1H NMR, DSC, TGA, FTIR and UV-Vis spectroscopy. Photolumi-nescence (PL) spectra shows that the emission of DCMH peaked at 625 nm is almost completely quenched in DMF solution with a concentration of 1 x 10~(-4) mol/L, however, in hybrid films, the PL intensity enhances obviously with increasing DCMH concentration even at the high loading content of 40 mol%. All the hybrid films exhibit PL emission around 646-650 nm and the peak position reveal little dependence on the concentration of dye, suggesting they can be used as red emissive materials in light-emitting diodes. The relationship between fluorescence lifetime and dye concentration is also investigated by time-resolved PL measurements.