Hybrid thin films of ZnO with porphyrins and phthalocyanines prepared by one-step electrodeposition

Abstract

Hybrid thin films of crystalline zinc oxide and the zinc complex of 5,10,15,20-tetrakis-(4-sulfonatophenyl)porphyrin (ZnTPPS) have been prepared by cathodic electrodeposition from different aqueous zinc salt solutions. Films from a solution containing zinc nitrate and the porphyrin derivate show a rough surface and porosity, whereas films prepared from an oxygen-saturated zinc chloride solution were very smooth. The presence of the porphyrin derivative in the deposition solution has a clear influence on the morphology of the hybrid films compared with pure zinc oxide films. In aqueous zinc nitrate solution the addition of the porphyrin derivative hinders the growth of zinc oxide. In contrast, the addition of the dye to the oxygen-saturated zinc chloride solution leads to an increase of the growth rate of ZnO /porphyrin hybrid films. An increased spectral absorbance was reached when two dyes (zinc complex of tetrasulfonated phthalocyanine and porphyrin) were added to the zinc nitrate solution since the electrodeposited hybrid thin films contained both dyes. UV-vis spectra revealed the presence of both macrocyclic metal complexes in the ZnO films.