Synthesis, Photophysics and Morphology of a Conjugated Polymer with Azobenzene Building Block in the Backbone

Abstract A conjugate polymer poly[ p ‐(phenyleneethylene)‐alt‐(phenyleneazophenyleneethylene)] (PPEPAPE) containing azobenzene building block in the polymer backbone was synthesized via Sonogashira cross‐coupling of 4,4′‐diiodoazobenzene and 1,4‐diethynyl‐2,5‐didodecyloxybenzene. All the monomers and the resulting polymer were well characterized. The polymer had a relatively high molecular weight and showed very good solubility (≧10 mg/mL) in common organic solvents. The photophysics of this polymer in solution and in film was investigated. The surface morphology of the films was studied by scanning electron microscope (SEM) and the relationship between the morphology and absorbance was discussed. This polymer has good film‐forming property, broad absorbance and no emission, which might make it a good candidate for the photovoltaic material in the solar cell.