Rectified photocurrent

Polymer pendant MtPcs (M Fe, Co, Np, Cu +) were used as films to produce a photoresponse. MV present in the solution was not effective as an acceptor, but Fe EDTA worked as an acceptor to enhance the photocurrent about 10 times A polymer bilayer coated electrode consisting of an electron-mediator film in the inner layer 49) and a sensitizer film (50) in the outer layer produced a rectified photocurrent In the presence of a sacrificial reductant (triethanolamine) in the solution, the bilayer coated electrode gave exclusively anodic photocurrent independent of the applied potential between —0.2 and —0.3 V vs SCE. 

McCann JE, Pezy J (1981) The measurement of the Hatband potentials of n-type and p-type semiconductors by rectified alternating photocurrent voltammetry. J Electrochem Soc 128 1735-1740... 

We have investigated the photocurrent behavior of multilayers of a Chi a-DPL (molar ratio 1/1) mixture on platinum in an aqueous electrolyte without added redox agents (80). Cathodic photocurrents with quantum efficiencies in the order of 10- were obtained with films consisting of a sufficient number of monolayers. The photocurrent was increased in acidic solutions. However, no appreciable photocurrent was observed with a single monolayer coated on platinum. The latter fact most probably results from minimal rectifying property of the metal surface and/or an efficient energy quenching of dye excited states by free electrons in... 

Tetraphenylporphine (TPP) and other metal porphyrine derivatives coated on platinum (87,88,89) or gold (89,90) electrodes have been investigated in photoelectrochemical modes. Photocurrents reported are cathodic or anodic, depending on the pH as well as the composition of the electrolyte employed. Photocurrent quantum efficiencies of 2% (89) to 7% (87) were reported in systems using water itself or methylviologen as the redox species in aqueous electrolyte. Photocurrent generation at Zn-TPP-coated metal cathodes (89) was interpreted in terms of a rectifying effect of the Schottky barrier formed at a metal-p-type... 

When a load is present, a potential difference develops between the terminals of the cell. This potential difference generates a current, which acts in the opposite direction to the photocurrent, and the net current is reduced from its short circuit value. This reverse current is usually called dark current in analogy with the current V), which flows across the device under an applied voltage, or bias, V, in the dark. Most solar cells behave like a diode in the dark, admitting a much larger current under forward bias ly > 0) than under reverse bias (V < 0). This rectifying behavior is a feature of photovoltaic devices, since an asymmetric junction is needed to achieve charge separation. For an ideal diode, the dark current density /dark( ) varies like... 

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