Supramolecular photocurrent-generating systems using porphyrin composite materials

Supramolecular design principles for a porphyrin-sensitized, wet-type solar cell are described. To construct efficient organic photocurrent-generating systems, the following two important targets exist: (i) kinetic control of photoinduced electron-transfer processes by spatial, three-dimensional alignment of photo-functional molecules (sensitizers, electron donors, acceptors, and mediators) and (ii) highly dense deposition of composites of the photo-functional molecules on an electrode. These objectives can be achieved by tailoring a photoactive multilayer using supramolecular interactions, such as molecular adsorption, inclusion, coordination, and recognition. Using these interactions, it is expected that the reduction of the costs of synthesis and the combinational fabrication of a simplified-molecular device will become possible. In addition, recent approaches toward the construction of supramolecular porphyrin-sensitized photovoltaic cells are introduced.