1/f noise and dye-sensitized solar cells

The adsorbed molecular species, such as H2O and I-2, that produce electron acceptor states on the TiO2 surface are found to generate 1/f noise in the electric current through nanocrystalline films of TiO2. It is suggested that the trapping and detrapping of electrons at the surface states is the cause of this noise. When the TiO2 film surface is coated with dyes, the passivation of the active surface sites suppresses 1/f noise. Implications of 1/f noise on the functioning of the dye-sensitized solar cell, notably the effect of adsorbed iodine in inducing recombinations, are discussed.