▎ 摘　　要

We report a novel technique to synthesize fluorescent carbon dots decorated graphene oxide (CDs-GO) sheets by microwave irradiation using citric acid as the precursor and ethylenediamine as the passivation agent. The samples are characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and ultra violet-visible spectroscopy (UV-Vis). Fluorescence studies reveal strong excitation wavelength dependent fluorescence behaviour for these nanocomposites dispersed in water. Third order nonlinear optical properties of these composites are studied using Z scan technique with Q-switched nanosecond pulsed Nd: YAG laser and the measured highest nonlinear optical susceptibility is 4.624x10(-10) esu. The optical limiting studies of these nanocomposites yield a lower limiting threshold of 104MW/cm(2) enabling them as a strong candidate for optical limiting applications. (C) 2019 Author(s).