Full-Color Phosphors from Amine-Functionalized Crosslinked Hybrids Lacking Metal Activator Ions

Sol–gel derived hybrids that contain OCH2CH2 (polyethylene glycol, PEG) repeat units grafted onto a siliceous backbone by urea, –NHC(=O)NH–, or urethane, –NHC(=O)O–, bridges have been prepared. It is demonstrated that the white light PL of these materials results from an unusual convolution of a longer lived emission that originates in the NH groups of the urea/urethane bridges with shorter lived electron–hole recombinations occurring in the nanometer-sized siliceous domains. The PL efficiencies reported here (maximum quantum yields at room temperature of ≈ 0.20 ± 0.02 at a 400 nm excitation wavelength) are in the same range as those for tetramethoxysilane–formic acid, and APTES–acetic acid, sol–gel derived phosphors. The high quantum yields combined with the possibility of tuning the emission to colors across the chromaticity diagram present a wide range of potential applications for these hybrid materials.