Photoelectrochemical response of Langmuir-Blodgett monolayer films containing donor-pi-acceptor azomethine dyes

Three amphiphilic azomethine dyes, (E)-N-octadecyl-2-[2-(4-N,N-dimethylamin ophenyl)azomethinyl]quinolinium iodide, (E)N-octadecyl-4-[2-(4-N,N-dimethyl aminophenyl)azomethinyl]quinolinium iodide, and (E)-N-octadecyl-6- [2-(4-N, N-dimethylaminophenyl)azomethinyl]quinolinium iodide, have been prepared by changing different relative positions of electron-accepting groups. They w ere successfully transferred onto indium-tin oxide slides by the Langmiur-B lodgett (LR) technique. Photoelectrochemical studies on these dyes' LB mono layer-modified ITO electrode were carried out. In 0.5 M KI solution contain ing 0.05 M I-2, the photocurrent generation quantum yield for these dyes va ried from 7.2 to 15.9%, depending on the linking positions. Dependence of t he photocurrent on the applied potential and the redox couple suggests that they undergo the photoinduced electron transfer mechanism of photoelectric conversion. (C) 2000 Academic Press.