Sensitization of thin-film-silicon by a phthalocyanine as strong organic absorber

Interfaces of either microcrystalline Si (μc-Si) on the organic sensitizer phthalocyaninatozinc (PcZn) or of PcZn on amorphous Si (a-Si) were prepared to study the compatibility of the film growth of Si by chemical vapor deposition with the thermal and chemical stability of PcZn. The compatibility could be reached and, composite structures were prepared of a-Si with PcZn by simultaneous deposition. An electronic interaction of Si and PcZn was indicated by an observed fluorescence quenching in PcZn by subsequently deposited μc-Si. The photoconductivity of a-Si was increased by absorption of light either in subsequently or simultaneously deposited PcZn as seen in photoconductivity spectra. The sensitization of Si by PcZn was thereby proven. The conditions to utilize this effect for a further development of thin film photovoltaic devices are discussed.