Synthesis of silver sulfide nanoparticles and their photodetector applications

Silver sulfide nanoparticles (Ag(2)S NPs) are currently being explored as infrared active nanomaterials that can provide environmentally stable alternatives to heavy metals such as lead. In this paper, we describe the novel synthesis of Ag(2)S NPs by using a sonochemistry method and the fabrication of photodetector devices through the integration of Ag(2)S NPs atop a graphene sheet. We have also synthesized Li-doped Ag(2)S NPs that exhibited a significantly enhanced photodetector sensitivity via their enhanced absorption ability in the UV-NIR region. First-principles calculations based on a density functional theory formalism indicated that Li-doping produced a dramatic enhancement of NIR photoluminescence of the Ag(2)S NPs. Finally, high-performance photodetectors based on CVD graphene and Ag(2)S NPs were demonstrated and investigated; the hybrid photodetectors based on Ag(2)S NPs and Li-doped Ag(2)S NPs exhibited a photoresponse of 2723.2 and 4146.0 A W(−1) respectively under a light exposure of 0.89 mW cm(−2) at 550 nm. Our novel approach represents a promising and effective method for the synthesis of eco-friendly semiconducting NPs for photoelectric devices.