Photocurrent generators derived from non-covalently assembled cyclodextrin nano-system

It is rather difficult to design a multilayer photocurrent generator system on ITO electrode, however, the preparation of thin film with high surface concentration of donor units is indispensable in order to achieve high conversion efficiency. The polymer film of the chromophores on the electrode was prepared by the potential sweep method. It was indicated that the self-aggregation can be suppressed by encapsulation of the porphyrin unit in the cavity of macro-cyclic host molecule, namely cyclodextrin. We established the non-equilibrium host-guest system with porphyrins and cyclodextrins for the first time. The photocurrent density and the quantum yield in the porphyrin-cyclodextrin system are remarkably improved. It was demonstrated that the high quantum yield, perhaps 25 times larger, arises from the isolation of the porphyrin unit by cyclodextrin through host-guest interactions.