Centrifugal Force-Assisted Preparation of Closely Packed Transition Metal Dichalcogenide Nanoscrolls for Enhanced Optoelectronic Performance

Abstract

Due to their unique spiral structure and unexpected properties, transition metal dichalcogenide (TMDC) nanoscrolls have been widely explored in the fields of optoelectronic devices, hydrogen evolution catalysis, and gas sensing. Unfortunately, the large-scale fabrication of a closely packed and clean TMDC nanoscroll is still a challenge, which hinders the potential application of TMDC nanoscrolls in optoelectronics. In this work, we report a centrifugal force-assisted method to prepare TMDC nanoscrolls with lengths ranging from tens to hundreds of micrometers by spin-coating poly(ethylene glycol) (PEG) on monolayer TMDC nanosheets, which were grown by chemical vapor deposition. The as-prepared TMDC nanoscrolls were wellcharacterized by optical microscopy, atomic force microscopy, ultralow-frequency (ULF) Raman spectroscopy, and transmission electron microscopy. The interlayer spacing of the nanoscrolls was found to be as small as 0.53 nm, indicating a closely packed and clean structure. The strong coupling between adjacent layers of the nanoscroll was further confirmed by the appearance of multiple layer-breathing mode peaks in the ULF Raman spectrum. Moreover, the nanoscroll prepared by spin-coating PEG showed much better optoelectronic performance, such as carrier mobility, photoresponsivity, photosensitivity, and external quantum efficiency, than the MoS 2 nanoscroll prepared by an ethanol droplet and a monolayer MoS 2 nanosheet. We not only provide a facile method for the large-scale preparation of TMDC nanoscrolls with a closely packed and clean structure but also demonstrate the promising potential of TMDC nanoscrolls in optoelectronic devices.