Direct Synthesis of MoS 2 Nanosheets in Reduced Graphene Oxide Nanoscroll for Enhanced Photodetection.

Due to their unique tubular and spiral structure, graphene and graphene oxide nanoscrolls (GONS) have shown extensive applications in various fields. However, it is still a challenge to improve the optoelectronic application of graphene and GONS because of the zero bandgap of graphene. Herein, ammonium tetrathiomolybdate ((NH 4 ) 2 MoS 4 ) was firstly wrapped into the ((NH 4 ) 2 MoS 4 @GONS) by molecular combing the mixture of (NH 4 ) 2 MoS 4 and GO solution on hydrophobic substrate. After thermal annealing, the (NH 4 ) 2 MoS 4 and GO were converted to MoS 2 nanosheets and reduced GO (RGO) simultaneously, and, thus, the MoS 2 @RGONS was obtained. Raman spectroscopy and high-resolution transmission electron microscopy were used to confirm the formation of MoS 2 nanosheets among the RGONS. The amount of MoS 2 wrapped in RGONS increased with the increasing height of GONS, which is confirmed by the atomic force microscopy and Raman spectroscopy. The as-prepared MoS 2 @RGONS showed much better photoresponse than the RGONS under visible light. The photocurrent-to-dark current ratios of photodetectors based on MoS 2 @RGONS are ~570, 360 and 140 under blue, red and green lasers, respectively, which are 81, 144 and 35 times of the photodetectors based on RGONS. Moreover, the MoS 2 @RGONS-based photodetector exhibited good power-dependent photoresponse. Our work indicates that the MoS 2 @RGONS is expected to be a promising material in the fields of optoelectronic devices and flexible electronics.