All-graphene-based transparent and flexible ultraviolet photodetectors

Abstract

The excellent electrical and optical properties make graphene suitable for transparent conductive electrodes in optoelectronic device applications. However, the lack of an energy bandgap of graphene has caused many obstacles in practical applications. To overcome this issue, graphene-based semiconductor heterojunctions have been proposed, but challenges still remain due to the chemically inert surface of graphene, which causes many difficulties in forming a junction. We have proposed an alternative strategy based on chemically modified graphene architecture in this context. This combination creates a novel platform based entirely on graphene material so that it can perfectly connect together. All-graphene-based transparent ultraviolet photodetectors comprised of a reduced graphene oxide layer and graphene quantum dots have been manufactured and tested. Under a 2 V applied voltage and 380 nm illumination wavelength, this structure has a responsivity of 2 A/W with a rise/decay duration of 100 s.