Molecular rectification: application in dye-sensitized solar cells.

A dye-sensitized heterojunction of configuration n-TiO2/PD-CuPC-MV/p-CuSCN (where PD = 3,4-pyridinedicarboxylic acid anchored to TiO2, CuPC = copper(II) phthallocyanine tetrasulfonic acid ionically linked to PD, and MV = Methyl Violet complexed to CuPC) is developed to demonstrate the applicability of molecular rectification to dye-sensitized solar cells as a strategy of suppressing recombination. Short-circuit photocurrent, open-circuit voltage, energy conversion efficiency, and incident photon to photocurrent conversion of this system are higher than that of the heterojunctions of configurations n-TiO2/PD-MV/p-CuSCN, n-TiO/CuPC-MV/p-CuSCN, and n-TiO2/MV/p-CuSCN. The impressively high rectification ratio and the mode of anchorage of CuPC toTiO2 are suggested as the cause of superior photovoltaic action of the cell TiO2/PD-CuPC-MV/p-CuSCN.