Delocalized electrons as a source of non-linearity: electron-phonon coupling and environmental effects beyond perturbation theory

The electronic revolution in the last century was based on the development of devices with a non-linear current vs voltage response. If we want to res-cale our devices at the molecular level to drive a molecular-electronic or a photonic revolution, we need molecular materials with a strongly non- linear behavior. Conjugated electrons, with their non-additive properties, are an obvious source of non-linearity in molecular materials, and conjugated polymers and molecules are among the most promising materials for advanced applications. More generally, the presence of delocalized electrons makes mixed-valence compounds and/or charge transfer (CT) salts good candidates for non-linearity.