An oligo-phenylenevinylene derivative encapsulated in sol-gel silica matrix

An oligo-phenylenevinylene (OPV) derivative [4,4'-(1,4-phenylenedivinylene)bis(N-methylpyridinium iodide)] (OPVD) has been introduced to silica film by a sol-gel process. The X-ray diffraction pattern shows that the crystallization of OPVD can be eliminated in the composite film. Fluorescence spectral results show that the luminescent peak of the OPVD in the composite film undergoes a blue shift at about 80 nm and its emission intensity is enhanced compared with that of OPVD in the solid state. Surface photovoltage spectroscopy (SPS), and electric field induced surface photovoltage spectroscopy (EFISPS) are used to investigate the electron process in the OPVD-SiO2 heterostructured composite film. The results indicated that silica acted as an electric-passivation layer of OPVD, which can explain the strong blue-shifted emission of OPVD in the composite film.