Photoelectric conversion from a hemicyanine dye containing zinc complex in a Langmuir-Blodgett film

A cathodic photocurrent was obtained from a hemicyanine dye containing zinc complex; [(CH3)(2)NC6H4CH=CHC5H4NC18H37]Zn-2(dmit)(2) (where dmit = 4,5-dimercapto-1,3-dithiole-2-thione), modified SnO2 electrode by Langmuir-Blodgett (LB) technology in a 1 M KCl electrolyte solution. The action spectrum conforms to the absorption spectrum very well indicating that the monomers on the surface of the electrode are responsible for the photocurrent generation. Some factors which may affect the observed photocurrent such as the bias voltage, the concentration of donor or acceptor in the electrolyte solution, pH value, and light intensity have been investigated. Data show that the quantum yield is X-fold increased when a conductive zinc complex anion is used with the LB films to replace the I- in the molecule of (CH3)(2)NC6H4CH=CHC5H4NC18H37I, so that this kind of compound can be evaluated as a promising photoelectric conversion material.