Strategy to Attain Remarkably High Photoinduced Charge-Separation Yield of Donor-Acceptor Linked Molecules in Biological Environment via Modulating Their Cationic Moieties

A series of ferrocene-porphyrin-fullerene linked triads (TC1, TC2, and TC4) possessing different numbers of cationic moieties were designed and prepared to achieve a high photoinduced charge-separation (CS) yield in a biological environment. In a solution, TC1, TC2, and TC4 demonstrated the formation of their nanoaggregates. Among the new triads, TC4 possessing the four cationic moieties exhibited the formation of a long-lived charge-separated state with the highest CS yield (86%) ever reported in cell membrane-like lipid bilayers, which is consistent with the largest change in the cell membrane potential of PC12 cells via the photoinduced CS under green light illumination. The highest CS yield in the biological environment can be rationalized by the well-tailored balance in hydrophobicity and hydrophilicity of TC4. This finding provides a strategy to improve greatly the photoinduced charge-separation yield of donor-acceptor linked molecules in the biological environment and also will be informative for extracting the full potential of the photoinduced charge-separated state toward biological applications.