A series of hairy-rod fluorene-alt-benzene based conjugated polymers with different substituted groups on phenylene were synthesized through Suzuki coupling polymerization. The optical properties, fluorescence quantum yields (QY) and electrochemical properties of these polymers were investigated. It was found that the optical properties of the polymers did not show obvious dependence on the alkyl length on phenylene. However, the spectral stability was increased, and the 0-1 transition and the full width at the half-maximum (FWHM) of photoluminescence spectra were decreased with the increase of the alkoxy length on phenylene. The nature (e.g. electron-donating and electron-withdrawing) of the substituted side groups on phenylene has obvious effect on the optical properties, QY and electrochemical properties of the polymers. Thus, the photophysical properties of the polymers can be tuned by attaching different substituted side groups onto the phenylene. The spectra of the polymers in solutions exhibit dependence on dielectric constants of the solvents used, and the spectra of the polymer solutions shift to longer wavelength with increasing the dielectric constants of the solvents.

Key words: polyfluorene, block copolymer, side chain, photophysical property, solvation effect