Photoelectric Response from Two Amphiphilic Nitrobenzene Dyes with Alkoxyl on a Monolayer-Modified ITO Electrode

Two amphiphilic nitrobenzene dyes 3-(CH 3 O)-4-(C 18 H 37 O) C 6 H 3 CH N NH C 6 H 4 NO 2 (dye 1 ) and 4-(C 18 H 37 O) C 6 H 4 CH N NH C 6 H 4 NO 2 (dye 2 ) were synthesized and deposited on semiconducting transparent ITO electrodes by a Langmuir−Blodgett (LB) technique. The photocurrent generations have been studied in a conventional photoelectrochemical cell. Action spectra of the photocurrent generation are coincident with the absorption of the LB film-modified electrodes, indicating that the dye aggregates in the LB film are responsible for the photocurrent. Some factors which may affect the observed photocurrent, such as existence of O 2, concentration of MV 2+ (methyl viologen) and H 2 Q (hydroquinone), pH values, and the bias voltage, have been investigated. On the basis of experiments, mechanism models for the photocurrent generation under different conditions are proposed.