Narrow Results

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.

The reactivity of phthalonitrile, tetrafluorophthalonitrile and 4,5-dibutoxyphthalonitrile with unmodified surfaces of ZnO and SiO₂ and with the modified systems SiO₂/Cp₂Co, ZnO/Cp₂Co, SiO₂/Zn(AcAc)₂ prepared by deposition of cobaltocene (Cp₂Co) and zinc acetylacetonate Zn(AcAc)₂, was studied ("in-situ-synthesis") in processes of phthalocyanine coatings. The formation of structural uniform phthalocyanines on carriers were established by UV-vis and mass spectra. The compounds were used then to compare their catalytic and photocatalytic activities in the oxidation of sulfide as a test reaction.

The photoelectroectrochemical studies of water soluble octacarboxylated oxotitanium (OTiOCPc), zinc (ZnOCPC), hydroxyaluminium ((OH)AlOCPc), dihydroxysilicon ((OH)₂SiOCPc), hydroxygallium (OHGaOCPc) and low symmetry zinc monocarboxy (ZnMCPc) phthalocyanines were performed. The dyes were adsorbed to nanoporous ZnO electrodeposited in the presence of eosin Y as structure directing agent (SDA) on FTO substrates by refluxing or soaking the films in a solution containing the dye of interest such that a full surface coverage was achieved. High external (IPCE) and internal (APCE) quantum efficiencies of up to 50.6% and 96.7% were achieved for the OTiOCPc complex. There was a lower overall cell efficiency for cells sensitized with phthalocyanines containing hydroxyl as axial ligand ZnO/(OH)₂SiOCPc, ZnO/(OH)GaOCPc and (OH)AlOCPc because of strong aggregation on the surface of the electrodes. To further suppress dye aggregation, the zinc complex of a new monocarboxylated phthalocyanine sensitizer with bulky naphtho side groups (ZnMCPc) was employed. Among the studied sensitizers, ZnMCPc gave the highest overall cell efficiency of phthalocyanine electrodeposited on ZnO of η = 0.48%.