Fast and Efficient Preparation of Exfoliated 2H MoS₂ Nanosheets by Sonication-Assisted Lithium Intercalation and Infrared Laser-Induced 1T to 2H Phase Reversion

Abstract

Exfoliated 2H molybdenum disulfide (MoS2) has unique properties and potential applications in a wide range of fields, but corresponding studies have been hampered by the lack of effective routes to it in bulk quantities. This study presents a rapid and efficient route to obtain exfoliated 2H MoS2, which combines fast sonication-assisted lithium intercalation and infrared (IR) laser-induced phase reversion. We found that the complete lithium intercalation of MoS2 with butyllithium could be effected within 1.5 h with the aid of sonication. The 2H to 1T phase transition that occurs during the lithium intercalation could be also reversed by IR laser irradiation with a DVD optical drive.

Interlayer Nanoarchitectonics of Two‐Dimensional Transition‐Metal Dichalcogenides Nanosheets for Energy Storage and Conversion Applications

“…Mallouk and co-workers reported complete lithium intercalation in a BuLi/hexane solution within minutes under mild sonication (135 W, ≈1.5 h). [56] The spacing between the adjacent layers of the intercalated LiMoS 2 is ≈6.31 Å, which is ≈0.15 Å larger than that of the pristine MoS 2 and matches the theoretical interlayer spacing of LiMoS 2 . Exposure of the LiMoS 2 samples in air results in further expansion, owing to hydration of the intercalated Li ions to form Li x (H 2 O) y MoS 2 .…”

“…In most reports, organolithium reagents were used as intercalating agents because of their solubilities in a wide range of solvents and the formation of reduced LiMX 2 with expanded c lattice. [18,[53][54][55][56][57] The lithium intercalation may be described as an ion-electron transfer topotactic reaction. n-Butyllithium (n-BuLi) is a commonly used intercalating agent.…”

Nickel Hydr(oxy)oxide Nanoparticles on Metallic MoS2 Nanosheets: A Synergistic Electrocatalyst for Hydrogen Evolution Reaction

“…The strong E 1g band peaked at 281 cm −1 along with the weak E 1 2g band peaked at 375 cm −1 confirms the dominant octahedral coordination of Mo in 1T‐MoS 2 57. The peaks at 112, 123, and 195 cm −1 are also observed in the Raman spectra of 1T‐MoS 2 in some reported literatures while the attributes of these peaks are not clear so far 47, 55, 57. X‐ray photoelectron spectroscopy (XPS) was employed to investigate composition and chemical state of the synthesized MoS 2 .…”

“…The Raman spectrum of the synthesized MoS 2 is also distinct from the commercial 2H‐MoS 2 , showing additional peaks at 146 cm −1 ( J 1 ), 233 cm −1 ( J 2 ), and 334 cm −1 ( J 3 ) which are attributed to the phonon modes in 1T‐MoS 2 superlattice structure (Figure S2b, Supporting Information) 47, 56. The strong E 1g band peaked at 281 cm −1 along with the weak E 1 2g band peaked at 375 cm −1 confirms the dominant octahedral coordination of Mo in 1T‐MoS 2 57. The peaks at 112, 123, and 195 cm −1 are also observed in the Raman spectra of 1T‐MoS 2 in some reported literatures while the attributes of these peaks are not clear so far 47, 55, 57.…”

Unconventional solution-phase epitaxial growth of organic-inorganic hybrid perovskite nanocrystals on metal sulfide nanosheets

“…As a result, photodetector based on the metallic MoS 2 nanosheets hybridized with MAPbBr 3 NCs showed a relatively high dark current density, leading to a relatively low on/off ratio of 1.4. It has been reported previously that metallic 1T MoS 2 can be reverted back to the semiconducting 2H phase by annealing [46] or laser irradiation [61]. We therefore partially converted the MoS 2 from 1T to 2H in the MAPbBr 3 /MoS 2 device by simply illuminating it with a 780 nm laser at 100 mW for 30 s, and the 2H concentration increased from 16% to 68% (Fig.…”