Abstract
Electron transport across a membrane is central to photosynthesis, to mitochondrial respiration and to the design of molecular systems for solar energy conversion. Relatively few synthetic molecules, however, have been shown to facilitate trans-port of electrons across a lipid bilayer We report here that Ccan act as both a photosensitizer for electron transfer from a donor molecule and a mediator for electron transport across a lipid bilayer membrane. The steady-state photocurrent density obtained from the Cndash;bilayer system is about 40 times higher, at comparable light intensities, than that of the carotene-porphyrin-quinone system previously the most efficient artificial system. The C-bilayer system has a quantum yield of about 0.04, while the stability (tens of minutes) and turnover number (electrons transported per Cbefore decay) of 10are one to three orders of magnitude greater than those of other systems We anticipate that other higher fullerenes may also provide the basis for efficient transmembrane electron-transport systems. © 1993 Nature Publishing Group.