The Impervious Route to Peptide-Based Dye-Sensitized Solar Cells

Electron transfer through peptide scaffolds has been studied for a long time as a useful and simple approach to investigate the mechanisms of the ubiquitous electron-transfer processes in biology. Here, we review our long-standing work in the field, focused on the study of the electronic conduction properties of hybrid devices based on peptide films immobilized on metal surfaces. In particular, we describe the electrochemical and photoelectrochemical properties of peptide-based self-assembled monolayers chemically linked to gold substrates through a disulfide group. Very recently, this work culminated in the construction of a prototype dye-sensitized solar cell, the photoactive element of which was constituted by a helical oligopeptide functionalized with a near-UV-absorbing chromophore. We also take advantage of the occasion to critically review the state of the art of the field, with suggestions for the issues needing further investigation.