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

In this report, WS 2 -reduced graphene oxide (WS 2 -rGO) hybrid was successfully synthesized through a hydrothermal reduction process in which WS 2 nanosheets (WS 2 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 WS 2 -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 WS 2 -rGO hybrid was 4.32 μA/cm 2 , which is approximately 800% of that of the bare WS 2 photodetector. Meanwhile, the photoresponsivity of as-prepared WS 2 -rGO hybrid increases linearly with the irradiation intensity, up to 9.3 μA/W at power density of 30 mW/cm 2 . In addition, the stability test exhibits no conspicuous degradation after 100 cycles. The enhanced performance of the WS 2 -rGO hybrid benefits from the high carrier mobility of rGO and the efficient separation of photogenerated carriers at the WS 2 -rGO interface. This research demonstrates that the WS 2 -rGO hybrid has a good prospect in PEC-type photodetectors.