Full-color phosphors from amine-functionalized crosslinked hybrids lackingmetal activator ions

Sol-gel derived hybrids that contain OCH2CH2 (polyethylene glycol, PEG) rep eat units grafted onto a siliceous backbone by urea, -NHC(=O)NH-, or uretha ne, -NHC(=O)O-, bridges have been prepared. It is demonstrated that the whi te light PL of these materials results from an unusual convolution of a lon ger lived emission that originates in the NH groups of the urea/urethane br idges with shorter lived electron-hole recombinations occurring in the nano meter-sized siliceous domains. The PL efficiencies reported here (maximum q uantum yields at room temperature of approximate to 0.20 +/- 0.02 at a 400 nm excitation wavelength) are in the same range as those for tetramethoxysi lane-formic acid, and APTES-acetic acid, sol-gel derived phosphors. The hig h quantum yields combined with the possibility of tuning the emission to co lors across the chromaticity diagram present a wide range of potential appl ications for these hybrid materials.