Vertically standing layered MoS₂ nanosheets on TiO₂ nanofibers for enhanced nonlinear optical property.

Vertical layered MoS₂ nanosheets rooting into TiO₂ nanofibers were successfully prepared by a facile two-step method: prefabrication of porous TiO₂ nanofibers based on an electrospinning technique, and assembly of MoS₂ ultrathin nanosheets through a simple hydrothermal reaction. Significant enhancement of nonlinear optical response of the MoS₂/TiO₂ nanocomposite was confirmed by an open-aperture z-scan measurement. The nanocomposite displayed strong optical limiting (OL) effects to ultrafast laser pulses with a low OL threshold of ~22.3 mJ/cm², which is lower than that of pristine TiO₂ nanofibers and MoS₂ nanosheets. In addition to the contribution of the strong nonlinear absorption of MoS₂ nanosheets and TiO₂ nanofibers, such phenomenon is also attributed to the unique structure of vertically standing layered MoS₂ nanosheets on TiO₂ nanofibers with a large amount of exposed edge states, large surface areas and fast electron transfer between TiO₂ and MoS₂. This work broadens our vision to engineering novel hierarchical MoS₂-based nanocomposite for efficiently enhanced nonlinear light-matter interaction.