Effects of alkylchain length on the efficiency of photoinduced electron transfer at gold electrodes modified with self-assembled monolayers of molecules containing porphyrin, ferrocene and thiol separated each other by alkylchains

Highly efficient visible light induced photocurrent generation was achieved at gold electrodes modified with self-assembled monolayers (SAMs) of porphyrin-ferrocene-thiol linked molecules separated from each other with alkylchains, in a solution containing methylviologen (MV2+) as an electron acceptor, The effects of the alkylchain length separating porphyrin and ferrocene on the efficiency were examined. The longer the alkylchain between porphyrin and ferrocene, the larger the photocurrent. These results suggest that the effective inhibition of energy transfer and reverse electron transfer is the key for the efficient photoinduced electron transfer at the gold electrodes modified with the SAMs of these molecules.