hybrid optical systems electrically tunable – SO_HYPE

The optical properties manipulation of organic compounds currently relies mainly on chemical engineering. Although at the molecular scale the polarizabilities achieved are remarkable, they are poorly transferred to the solid state in real devices which, moreover, suffer from stability over time. SO HYPE aims at evaluating the relevance of a new approach, based on hybrid organic / 2D materials heterostructures, which should both allow a manipulation of these optical properties by physical parameters (electrostatic and mechanical) and an improvement of the stability of the organic constituents. For this purpose, the zwitterionic quinone-diimines (ZQDIs) have been identified as building blocks of choice resulting from an unusual property: they possess a perpendicular permanent dipole, intimately linked to two strongly polarizable p-electron systems. From a structural point of view, the combination of the permanent dipole and the small size of the ZQDIs allow for an extremely compact, and therefore potentially robust, self-assembled monolayers (SAM) of vertically arranged ZQDIs. The imagined device consists in inserting such SAMs into a planar capacitor based on heterostructures of graphene and hexagonal boron nitride that can generate, on-chip, an intense electric field, parallel to the permanent dipoles of ZQDIs. Given the intimate link between the strength of the dipole, which can be controlled by this field, and the polarizability of the p-electron systems, electrical manipulation of the optical properties of ZQDIs is expected. In addition, the compatibility of these structures with flexible substrates will allow to study the influence of mechanical stresses. Beyond these static effects, the electro-optical activity will be studied in frequency, in order to evaluate the relevance of this type of device for electro-optical modulation.