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

Abstract

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.