Laser-assisted reduction of graphene oxide for flexible, large-area optoelectronics

This paper reviews recent work on the development and use of a low-temperature, laser-based method for the efficient reduction of graphene oxide (GO) films. The method utilizes a laser beam for the in-situ and nonthermal reduction of solutionprocessed GO layers onto arbitrary substrates. Compared to other reduction techniques, it is single-step, facile, and can be performed at room temperature in ambient atmosphere without affecting the integrity of the either the graphene lattice or the physical properties of the underling substrate. Using this method, conductive layers of reduced GO with a sheet resistance down to ~700 ω/sq, are obtained. This is much lower than sheet resistance values reported previously for GO layers reduced by chemical means. As a proof of concept, laser-reduced GO layers were successfully utilized as the transparent anode electrodes in flexible bulk-heterojunction OPVs and as the channelmaterial in field-effect transistors. To the best of our knowledge, this is the only example of an in-situ, postfabrication method for the reduction ofGOand its implementation in fully functional opto/electronic devices. The nonthermal nature of the method combined with its simplicity and scalability, makes it very attractive for the manufacturing of future generation large-volume graphene-based opto/electronics.