Photo-switchable molecular monolayer anchored between highly transparent and flexible graphene electrodes

A molecular ultra-thin film (for example, a molecular monolayer) with graphene electrodes would allow for the realization of superior stable, transparent and flexible electronics. A realistic prospect regarding the use of graphene in two-terminal molecular electronic devices is to fabricate a chemically stable, optically transparent, mechanically flexible and molecularly compatible junction. Here we report on a novel photo-switchable molecular monolayer, one side chemically and the other side physically anchored between the two graphene electrodes. The photo-switchable organic molecules specified with an electrophilic group are chemically self-assembled into a monolayer on the graphene bottom electrode, while the other end is physically contacted to the graphene top electrode; this arrangement provides excellent stability for a highly transparent and flexible molecular monolayer device with a high device yield due to soft contacts at the top electrode interface. Thus, the transparent graphene electrodes allow stable molecular photo-switching due to photo-induced changes in the molecular conformational length.