▎ 摘　　要

In the current work, graphene oxide nanocomposites containing silver and gold nanoparticles i.e., Ag-GO and Au-GO, were formed by reducing Ag+ and Au+ cations with black tea extract. The precise reduction of precursors is facilitated by the water-soluble, highly reactive reducing agent referred as tea polyphenols. To confirm the morphological, structural, and optical properties of the synthesized GO, Ag-GO and Au-GO samples, energy-dispersive X-ray spectroscopy (EDAX), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman spectroscopy and UV-Vis spectroscopy are carried out. The accumulation of Ag and Au NPs on the surface of graphene oxide is observed by scanning electron microscopy. Measurements of the current-voltage (I-V) and transient photocurrent (I-t) at illumination intensities of 5 mW/cm2 by varying bias voltage in the range of 10-30 V with different wavelengths are examined. A bias voltage of 30 V and a monochromatic light of wavelength (480 nm) having intensity of 5 mW/cm2 at room temperature provided detectivities for Ag-GO and Au-GO nanocomposites of 4.96 & POUND; 108 (Jones) and 0.75 & POUND; 108 (Jones), respectively. According to the analysed photoresponse properties, Ag-GO and Au-GO nanocomposites have shown the potential for use in future opto-electronic device applications.