Effect of chemical structure and deposition method on optical properties of polyazomethines with alkyloxy side groups

Abstract Three (two novel) conjugated, thiophene phenylene based polyazomethines have been obtained parallel, by chemical vapour deposition (CVD) and by chemical synthesis. They were subsequently identified and characterised by an X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry and detailed UV–Vis-NIR spectroscopy. Absorption spectra of the polymers' solutions and thin films have been examined. The spectra of polyazomethines without, with methoxy and with octyloxy side chains attached to the polymer backbone showed a conjugation-improving effect of alkyloxy side chain introduction. A comparison of spectra of the same polyazomethine's thin films deposited separately by spin-on and CVD methods revealed decrease in conjugation of compounds obtained during CVD. Additionally, amorphous character of the investigated thin films allowed to calculate the absorption edge parameters, in a way typical for amorphous semiconductor and to discuss their values in the context of chemical structure and deposition method. Surface imaging with atomic force microscope revealed different character of thin films deposited by spin-on and CVD methods.