Photoconductive enhancement effects of graphene quantum dots on ZnO nanoparticle photodetectors

Graphene quantum dots (GQDs) are a new class of zero dimensional carbon materials and have fascinating optical and electric properties. Many different methods for GQDs synthesize have been reported and GQDs have been proved very promising for biomedical imaging and photovoltaics applications. In order to further investigate the application of GQDs, here we report solution processable ultraviolet (UV) photodetector fabricated from ZnO nanoparticles (NPs) and from GQDs synthesized from hydrothermal method. The photodetector employing GQDs showed enhanced photoresponsivity and improved transient response. These improvements are explained by referring to the energy band diagram of the interfacial region of ZnO NPs and GQDs. The GQDs in this work demonstrated high potential for solution processable optoelectronics.