Electrical and photoelectrical properties of dye-sensitized allyl viologen-doped polypyrrole solar cells

The electrical and photoelectrical properties of an organic Schottky barrier device have been studied. The Schottky barrier device is based on spin-coated thin film of allyl viologen-doped polypyrrole (AV-PPy) sensitized with pyronine (PYR) dye, which is sandwiched between indium tin oxide (ITO)-coated glass and aluminum electrodes. The effect of dye sensitization on the electrical and photoelectrical parameters and photogeneration process has been described in this paper. It is found that the dye sensitization decreases the depletion layer width and diode quality factor of the device, whereas the mobility and carrier concentration increases on dye sensitization in AV-PPy thin film. The absorption spectrum of PYR complements that of AV-PPy in the visible region of the solar spectrum. It is also observed that the absorption spectra of PYR-sensitized AV-PPy thin film are broader and the number of photons absorbed in the visible region is higher than in the AV-PPy thin film. It has also been confirmed from the fluorescence spectra of PYR-sensitized AV-PPy thin film that the incident energy absorbed by the PYR dye does not give rise to fluorescence, and absorption of the incident light is generating the photocurrent. The PYR dye molecules enable the separation of charges photogenerated by the polymer before radiative recombination.