A facile and general route for the synthesis of semiconductor quantum dots on reduced graphene oxide sheets

Owing to its unique graphitized basal plane nanostructure and intriguing physicochemical properties, graphene is considered as an ideal support for developing nanocomposites for various applications. In this study, a facile and general method was developed for the first time to synthesize a variety of semiconductor quantum dots (SQDs) supported on reduced graphene oxide (RGO) sheets, including RGO/metal oxide and RGO/metal sulfide nanocomposites. The as-prepared nanocomposites were investigated by X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectra, X-ray photoelectron spectroscopy and transmission electron microscopy. It was found that by using octadecylamine (ODA) as both reductive and dispersing agent, the resulting metal oxide and sulfide SQDs were all homogeneously decorated on the surface of RGO sheets. The optical properties of the as-synthesized RGO/SQDs nanocomposites were studied through ultraviolet-visible and photoluminescence spectroscopy. To demonstrate one potential application, the RGO/NiO nanocomposites were used as electrode materials for electrochemical supercapacitors, which exhibit enhanced capacitive performance and long cycle life. It is expected that our prepared RGO/SQDs nanocomposites could serve as promising candidates for power source, catalysis, optical sensitizer and optoelectronic applications.