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[21a-W351-5] Photoconductivity for AgNPs-TiO2 films (2)
Keywords:silver-nanoparticle,titanium dioxide,photoconductivity
TiO2 is utilized for photoelectrode of dye-sensitized solar cells (DSCs) where organic dye sensitizers are adsorbed on TiO2 surface. Most organic dyes are known to deteriorate under the sunlight, which should be a problem to be improved. We have focused in the fact that electron transfer from metal nanoparticles (MNPs) to TiO2 takes place by photoirradiation; MNPs could be used as photosensitizers instead of organic dyes. Ag nanoparticles (AgNPs) are promising candidates for the photosensitizers.
The AgNPs were successfully grown in TiO2 mesopores and photocurrent was observed for the AgNPs-TiO2 hybrid films. In this report, we investigate the mechanism for the photoconduction.
The hybrid films were prepared as follows. Porous TiO2 films were prepared on ITO substrates by sintering TiO2 nanoparticles paste. The films were immersed in a silvernitrate-dimethylacetamide solution to grow AgNPs in the TiO2 mesopores. The hole-transporting polymer P3HT was spincoated on the film and an Au electrode was evaporated. The light with 100mW/cm2 was irradiated on to the ITO substrate.
The photocurrent was observed to increase depending on the photoirradiation time. Since increase in the density of the AgNPs in porous TiO2 was observed by photoirradiation in optical absorption spectra, the increase in the photocurrent could be caused by the increase in the density of AgNPs. Interestingly, the photocurrent for the hybrid film in the positive bias region became larger than that observed in the negative bias region by repeating the photocurrent measurement. This finding could be based on the increase in the density of AgNPs formed by photoirradiation during the photocurrent measurement.
The AgNPs were successfully grown in TiO2 mesopores and photocurrent was observed for the AgNPs-TiO2 hybrid films. In this report, we investigate the mechanism for the photoconduction.
The hybrid films were prepared as follows. Porous TiO2 films were prepared on ITO substrates by sintering TiO2 nanoparticles paste. The films were immersed in a silvernitrate-dimethylacetamide solution to grow AgNPs in the TiO2 mesopores. The hole-transporting polymer P3HT was spincoated on the film and an Au electrode was evaporated. The light with 100mW/cm2 was irradiated on to the ITO substrate.
The photocurrent was observed to increase depending on the photoirradiation time. Since increase in the density of the AgNPs in porous TiO2 was observed by photoirradiation in optical absorption spectra, the increase in the photocurrent could be caused by the increase in the density of AgNPs. Interestingly, the photocurrent for the hybrid film in the positive bias region became larger than that observed in the negative bias region by repeating the photocurrent measurement. This finding could be based on the increase in the density of AgNPs formed by photoirradiation during the photocurrent measurement.