Long-Distance Sequential Charge Separation at Micellar Interface Mediated by Dynamic Charge Transporter: A Magnetic Field Effect Study.

Abstract

Construction of photogenerated long-lived charge-separated states is crucial for light-energy conversion using organic molecules. For realization of cheap and easy-to-make long-distance electron transfer (ET) systems, we have developed a supramolecular donor(D)-chromophore(C)-acceptor(A) triad utilizing a micellar interface. Alkyl viologen (A(2+)) is adsorbed on the hydrophilic interface of Triton X-100 micelle, which bears D units in the hydrophobic core. Excited triplet state of a hydrophobic flavin C entrapped in the supercage gives rise to primary ET from D, which is followed by the secondary ET from C(-•) to A(2+) to give the long-lived (>10 μs) charge-separated state with negligible yield of escaped C(-•). Analysis of magnetic field effect reveals that diffusion of C(-•) from the core to the hydrophilic interface leads to long-distance ET with a low charge recombination yield of ∼20%. This novel concept of "dynamic charge transporter" has important implications for development of photon-energy conversion systems in solution phase.