Dye sensitized membranes within mesoporous TiO2 Photocurrents in aqueous solution

Abstract

Mesoporous TiO2 film electrodes were modified with membranes consisting of alkyl phosphonic acids with either a sulphonate or pyridinium head group Dyes (substituted porphyrins (1 2 and 3) a substituted chlorin (4) and a substituted Ru tris-bipyridyl complex (5)) with tailored ionic (carboxylates sulfonates and ammonium) and hydrophobic functionalities were synthesized The membrane modified electrodes were loaded with these dyes by self-assembling based on mutual charge compensation and hydrophobic interactions The membrane electrodes can generate photocurrents upon white light illumination (16 5 mW/cm(2)) in the range of 20-50 mu A/cm(2) in aqueous 01 M KI solution Dyes 3 and 4 perform better on the pyridinium membrane than directly attached via their carboxylate functionality This demonstrates charge injection through the membrane into the conduction band of TiO2 ZINDO/S calculations indicate that the pyridinium head group assists this process (C) 2010 Elsevier B V All rights reserved