Fabrication of Flexible and Transparent Conductive Nanosheets by the UV-Irradiation of Gold Nanoparticle Monolayers

Conductive films that are highly transparent and flexible are extremely attractive for emerging optoelectronic applications. Currently, indium-doped tin oxide films are the most widely used transparent conductive films and much research effort is devoted to developing alternative transparent conductive materials to overcome their drawbacks. In this work, a novel and facile approach for fabricating transparent conductive Au nanosheets from Au nanoparticles (AuNPs) is proposed. Irradiating an AuNP monolayer at the air-water interface with UV light results in a nanosheet with approximate to 3.5 nm thickness and approximate to 80% transparency in the UV-visible region. Further, the so-fabricated nanosheets are highly flexible and can maintain their electrical conductivity even when they are bent to a radius of curvature of 0.6 mm. Fourier-transform infrared and X-ray photoelectron spectroscopy characterizations reveal that the transformation of the monolayer of AuNPs into the nanosheet is induced by the photodecomposition and/or photodetachment of the dodecanethiol ligands capping the AuNPs. Further, the UV-irradiation of a hybrid monolayer consisting of AuNPs and silica particles affords the patterning of Au nanosheets with periodic hole arrays.