O₂‑Triggered Directional Switching of Photocurrent in Self-Assembled Monolayer Composed of Porphyrin- and Fullerene-Terminated Helical Peptides on Gold

Abstract

Directional switching of photocurrent generation in response to oxygen is attained with the self-assembled monolayer (SAM) composed of porphyrin- and fullerene-terminated helical peptides. The anodic photocurrent of the porphyrin SAM under argon gas is successfully switched over to the cathodic photocurrent in the presence of oxygen gas only in the copresence of the fullerene-terminated helical peptide. The first-principle calculations explain that the cathodic photocurrent is promoted as a result of suppression of the anodic photocurrent due to the small electron coupling between the lowest unoccupied molecular orbitals of fullerene and the amide moieties of electron mediating helix peptides