Polyconjugated azomethine layers by sequential condensation of al,al'-dialdehyde-oligothiophenes and 4,4'-diamino-diphenylenes on ITO/glass electrodes

Sequential (alternate) azomethine condensation of aldehyde end-capped oligothiophenes (Tn, n = 3, 6, and 8) with p-diaminobiphenile (DAB) or p-diaminofluorene (DAF) on 3-aminopropyltrimethoxysilane-primed (ATS-primed) ITO/glass is reported. The layers have been characterized by cyclic voltammetry, UV-vis spectroscopy, photoluminescence, XRD, and AFM. The oligothiophene layers first produced on the ATS-primed ITO are dense like ferrocene monolayers for T3 (4 x 10(-10) mol cm(-2)) and ca. 3 times less dense for T6 and T8 (1.5 x 10(-10) mol cm(-2)). The subsequent sequential growth occurs regularly with T3 but its rate is ca. 50% lower for T6 and almost null for T8. The condensed films are free of major defects and have the same roughness as the primed surface. Typical brush-electrodes formed by ATS/T3/(DAF/T3)(4) and ATS/T6/(DAF/T6)(2) sequences are fluorescent and reversibly protonated to colored films by perchloric acid in acetonitrile and undergo reversible iodine-doping.