Hierarchical van der Waals Heterostructure Strategy to Form Stable Transition Metal Dichalcogenide Dispersions

Junmo Park, Sungmin Bong, Jaehyun Park, Eunji Lee, Sang Yong Ju

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Although various methods have been developed to disperse transition metal dichalcogenides (TMDCs) in aqueous environments, the methodology to generate stable TMDC dispersions remains challenging. Here, we developed a hierarchical van der Waals (vdW) heterostructure-based strategy to disperse few-layered TMDCs (WS2, MoS2, WSe2, and MoSe2) using both hexagonal boron nitride (hBN) and sodium cholate (SC) as synergistic vdW surfactants. By showing long-term stability of up to 3 years, the extinction spectra of these TMDC/hBN/SC dispersions exhibit the most blue-shifted excitonic transitions, low background extinction, good colloidal stability, and dispersion stability upon ultracentrifugation compared to other dispersion methods. Hierarchical stacking having TMDCs and hBN/SC as core and shell parts is probed by electrostatic/atomic force microscopy and zeta potential, and its origin was attributed to surface energy matches. Along with the synergetic effect between TMDCs and hBN, the blue shift was ascribed to compressive strain on the TMDCs caused by hBN wrapping. The results of transmission electron microscopy show that the TMDCs in the dispersions have defective, few-layered structures with flake sizes that are less than a few hundred nm2. Raman spectroscopy is used to study not only the existence of compressive strain but also various interlayer coupling between TMDC and hBN. The hierarchical structures of TMDC/hBN/SC are discussed in terms of surface energies and topographies. This method is invaluable to provide a general methodology to disperse various surface-corrugated dimensional materials for various dispersion-based applications.

Original languageEnglish
JournalACS Applied Materials and Interfaces
Publication statusAccepted/In press - 2022

Bibliographical note

Funding Information:
This research was supported financially by the Basic Science Research Program (2020R1F1A1076983 and 2020R1A4A1017737) and Technology Development Program to Solve Climate Changes (2020M1A2A2080748) through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science, and Technology.

Publisher Copyright:
© 2022 American Chemical Society.

All Science Journal Classification (ASJC) codes

  • Materials Science(all)


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