IMPROVEMENT IN PHOTOELECTRIC CONVERSION OF A NANOSTRUCTURED TIO2 ELECTRODE COSENSITIZED WITH PHTHALOCYANINE AND PORPHYRIN

The cosensitization afa nanostructured titanium dioxide (TiO2) electro de with tetrasulfonated gallium phthalocyanine (0.39) and tetrasulfona ted zinc porphyrin (0.61) greatly enhances thf photocurrent response i n the GaTsPc Q band (640-760 nm), with sixtyfold improvement in the qu antum efficiency al 700 nm, and markedly decreases the photocurrent re sponse in the Soret band of ZnTsPP, with an eightfold drop of the quan tum efficiency at 430 nm. The quantum efficiency 32.2% nt 700 nm is ob tained for monochromatic illumination at 13.8 mu W . cm(-2), which pre sents one of the highest efficiencies reported for long wavelengths. T his is attributed tit the formation of the Pc/PP heteroaggregates on t he cosensitized TiO2 electrode resulting from charge-transfer interact ion.