Enhanced photoresponse of tungsten disulfide-reduced graphene oxide hybrid for photoelectrochemical photodetectors

In this report, WS2-reduced graphene oxide (WS2-rGO) hybrid was successfully synthesized through a hydrothermal reduction process in which WS2 nanosheets (WS2 NSs) were prepared by a lithium-ion intercalation and exfoliation technique. The photodetection properties of as-synthesized samples have been systematically investigated using a photoelectrochemical (PEC) system, which presents a reproducible photoresponse of WS2-rGO under zero bias, indicating that such hybrid is a promising photoanode for self-powered photodetectors. At a bias of 0.8 V, the photocurrent density of WS2-rGO hybrid was 4.32 μA/cm2, which is approximately 800% of that of the bare WS2 photodetector. Meanwhile, the photoresponsivity of as-prepared WS2-rGO hybrid increases linearly with the irradiation intensity, up to 9.3 μA/W at power density of 30 mW/cm2. In addition, the stability test exhibits no conspicuous degradation after 100 cycles. The enhanced performance of the WS2-rGO hybrid benefits from the high carrier mobility of rGO and the efficient separation of photogenerated carriers at the WS2-rGO interface. This research demonstrates that the WS2-rGO hybrid has a good prospect in PEC-type photodetectors.