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

•Ag+ and Au+ cations were reduced by black tea extract to synthesize the plasmonic nanocomposite Ag-GO and Au-GO.•The surface alteration caused by Ag and Au nanoparticles on GO aids in the improvement of photosensitivity.•At wavelengths of 480 nm, 520 nm, and 670 nm, photo-responsive properties were evaluated at varying bise voltages.•The responsivity of Ag-GO and Au-GO nanocomposite photodetector was 0.98 mA/W and 0.11 mA/W at 480 nm, respectively.