Photoresponse of surface modified graphene oxide by green synthesized silver and gold nanoparticles

Abstract

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 × 108 (Jones) and 0.75 × 108 (Jones), respectively. According to the analysed photoresponse properties, Ag-GO and Au-GO nanocomposites have shown the potential for use in future optoelectronic device applications.