Characterization of [Fe(o-phen) 3][Ni(CS 3) 2] as a photosensitizer for wide-band gap semiconductor (ZnO) electrodes in acetonitrile media

Abstract

A newly synthesized transition metal complex tris-1,110-ortho-phenanthroline iron (II) bis-thiocarbonato nickelate (II), [ [Fe(o-phen) 3][Ni(CS 3) 2], has been studied for its photosensitizing properties at n-ZnO semiconductor electrodes prepared by spray pyrolysis and sol-gel techniques. The absorption spectrum of this inorganic complex in acetonitrile solution exhibits a strong peak at 462 nm and a shoulder at 510 nm wavelength of light. From cyclic voltammetric studies it has been found that this compound can undergo reversible, one-electron transfer oxidation with formal redox potential E 0 = 0.985 V vs. SSCE in acetonitrile medium. The sensitization of the photocurrent at the ZnO electrode by the test dye was controlled by determining current-potential curves and action spectrum. As compared with sprayed ZnO thin films, particulate films prepared by sol-gel technique were found to give better performance.