Three-dimensional flower-like MoS2 strung by multi-wall carbon nanotubes: a versatile alternative for high performance optical limiters

Abstract

Heterostructures based on transition-metal dichalcogenide layered materials show great potential for various applications in nonlinear photonic devices such as optical switches, mode-locking lasers, and optical limiters. Herein, we report the design and synthesis of a hierarchical heterostructure of multi-wall carbon nanotubes (MWCNTs) decorated by three-dimensional molybdenum disulfide (MoS2). The unique MoS2/MWCNT heterostructure was successfully synthesized by a simple one-pot hydrothermal method, as confirmed by field emission scanning and transmission electron microscopies, X-ray diffraction, Raman spectrum, and X-ray photoelectron spectroscopy. The nonlinear optical (NLO) and optical limiting (OL) responses of the heterostructured MoS2/MWCNT and those of its individual components were investigated by the Z-scan technique at 532-nm with nano- and picosecond pulsed-laser sources. The NLO and OL properties of the MoS2/MWCNT heterostructure were improved compared with those of MoS2 and MWCNTs individually. The OL threshold of the heterostructured MoS2/MWCNT was 0.53 J/cm2, which is lower than or comparable to those of either common transition-metal dichalcogenides or graphene-like compounds. The NLO mechanisms are attributed to nonlinear absorption and nonlinear refraction at a picosecond timescale combined with nonlinear scattering induced by the MWCNTs at a nanosecond timescale. The improvements in NLO and OL performance are also attributed to photo-induced interfacial charge transfer between MoS2 and MWCNTs in the unique heterostructured MoS2/MWCNT. We report an efficient method of fabricating novel heterostructures with controllable NLO response. The unique morphology and excellent NLO properties obtained from these MoS2/MWCNT heterostructures show great potential for future optical and photonic applications.