Preparation and Photoelectrochemical Properties of Fullerene Modified ITO Electrodes Using Self-Assembled Monolayer

抄録

Fullerene (C₆₀) immobilized indium-tin-oxide (ITO) electrodes were prepared by a technique of self-assembled monolayers (SAMs) using five compounds of alkyldiamine (NH₂(CH₂)nNH₂; n = 4, 6, 8, 10 and 12). These C₆₀/diamine-SAMs modified ITO (C₆₀/n/ITO; n = 4, 6, 8, 10 and 12) electrodes were examined in terms of properties of electrochemical and photoelectrochemical responses. The C₆₀ surface coverage of C₆₀/n/ITOs estimated was ca. 3×10⁻¹⁰ to 4×10⁻¹⁰ mol cm⁻². The stable anodic photocurrent appeared immediately after the irradiation of the C₆₀/n/ITO electrode in 0.1 M Na₂SO₄ containing 50 mM ascorbic acid (AA) as an electron sacrificer with λ = 400−600 nm, light power of 4.0−6.5 mW cm⁻² and electrode potential of −0.15 V to +0.15 V vs. Ag/AgCl (saturated KCl). The photocurrents generated by C₆₀/n/ITOs increased with the number of the methylene unit (n) except for n = 12. These results have shown that increasing the length of the methylene contributes to only immobilization of C₆₀, because of highly ordered structure of diamine-SAMs.