Synthesis、Structures、Organic/inorganic Hybrid and Property of Self-assembled Optoelectronic Supramolecular Nanostructrures Directed by Oligophenylenevinylene(OPV)-series Molecules

In this research, oligo(2,5-bis(octyloxy)-p-phenylene vinylene) (OHC-Tri-BOPV-CHO) was successfully synthesized via the Horner-Wittig Reaction. A series of experiments including optical properties, investigation of self-assembly nanostructure and organic/ inorganic hybrid had been done on OHC-Tri-BOPV-CHO and oligo(2,5-bis(hexyloxy)-p-phenylene vinylene) (OHC-Tri-BHPV-CHO). We used UV and PL to study the optical properties of OHC-Tri-BOPV-CHO and OHC-Tri-BHPV-CHO compounds dissolving in the chloroform, hexane, and decane and in solid thin films by spinning coating. From the UV spectroscopy, the intensity of absorption peaks increase with solution’s concentration. And the compounds dissolving in different solvent showed the absorption peaks would be blue-shifted with increasing the solvent polarity while the PL peaks red-shifted. Nevertheless, the solid thin films always showed red-shifted in both UV/vis absorption and PL spectra compared to the compounds in solutions. Moreover, the self-assembly nanostructure of compounds in different solvent (hexane、decane、chloroform、THF) and concentration was also investigated by AFM and TEM. The change of self-assembly nanostructure with the concentration was parallel with the result of PL investigation. It is believed that the driving forces for all above self-assembly processes were the combination of dipole-dipole interaction, π-πinteraction, and Van der Waals force. The compounds of OHC-TriBHPV-CHO in THF self-assembled to form a very thin film, which tended to roll up into a hollow tubular structure to decrease the surface energy. Due to the longer length of side chain, OHC-Tri-BOPV-CHO molecules could only arrange into plank-like long stripes structure in THF and slightly roll up at film edge ( in hexane ), or even stack up with each other ( in chloroform ). At last, we took the tubular self-assembly structures of OHC-Tri-BOPV-CHO and OHC-Tri-BHPV-CHO in THF solvent as a structure base to further study the hybrid nano-strucutures with titania and silica.The result showed that the wavelength of luminescence of the titania hybrid series was red-shifted compared to the silica hybrid series, and the luminescent structure of the silica hybrid series has longer length but less dense than that of the titania hybrid series.