Photoinduced electron transfer across a gold supported octadecanethiol/phosphatidylcholine hybrid bilayer membrane mediated by C-60 in different redox species solution

Electron transfer across the biomembrane is central to photosynthesis, to m itochondrial respiration and to the design of molecular systems for solar e nergy conversion. We report here that gold supported octadecanethiol/phosph atidylcholine hybrid bilayer membrane mediated by C-60 (abbreviated C-60 HB M) can act as both a photosensitizer for electron transfer from a donor mol ecule and a mediator for electron transport across a hybrid bilayer membran e. The steady-state photocurrent behaviors in different concentration of as corbate, Co(bpy)(3)(2+/3+) Or Fe(CN)(6)(4-/3-) solution have been studied. The rate-limiting step of the whole photoinduced electron transfer depends on the applied potential and the redox concentration in solution. The C-60 HEM electrode was fabricated for the first time and there is no investigati on on C-60 incorporated octadecanethiol/phosphatidylcholine hybrid bilayer membrane in literature. The sigmoidal-shaped steady-state photocurrent vers us the applied potential curve is first observed and it is different from t he linear-shaped i(ph)/E curve of C-60 modified bilayer lipid membrane repo rted by Bensasson et al. [R.V. Bensasson, J.-L. Garaud, S. Leach, G. Miquel , P. Seta, Chem. Phys. Lett. 210 (1993) 141]. (C) 2000 Elsevier Science S.A . All rights reserved.