Controlled Production of MoS2 Full‐Scale Nanosheets and Their Strong Size Effects

Abstract

AbstractThe production of 2D nanosheets (2D NSs) with all sizes (1–100 nm) and few (<10) layers is highly desired but remains great challenge. Herein, the top‐down production of molybdenum disulfide (MoS2) NSs with wide‐range (161–10 nm) controlled sizes is reported. Considering the recently achieved MoS2 quantum sheets (QSs) with sizes of ≈2 nm, full‐scale NSs of MoS2 are successfully produced. The top‐down method combines silica‐assisted ball‐milling and sonication‐assisted solvent exfoliation. Ball‐milling with controlled time enables the production of multiscale NSs with varying distributions, which are then precisely separated by cascade centrifugation. Multiple spectroscopic techniques reveal the dramatic size dependence, indicating prominent quantum confinement and edge effects of the MoS2 NSs. The NSs‐poly(methyl methacrylate) (PMMA) hybrid thin films demonstrate strong size effects in nonlinear saturation absorption (NSA). Both (absolute) modulation depths and saturation intensities can be broadly modulated by simple variation of the NS sizes. With the sizes down from 161 to 10 nm, the modulation depths are increased from 27.0% to 51.3% and the saturation intensities are decreased from 33 419 to 21.2 kW cm−2 (3341.9–2.12 nJ cm−2). The work greatly facilitates the mass production and full exploration of 2D NSs with all sizes.