Analytical grade solvents and compounds were used for preparation.Tetraethoxysilane (TEOS,TianjinChemicalsCo.),
3-(triethoxysilyl)-propyl isocyanate (TESPIC,Aldrich),4-hydroxy-ben- zaldehyde (Aldrich),and 1 pyrenecarboxaldehyde (Aldrich) were used as received.