Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Ionic solutions of two-dimensional materials

Abstract

Strategies for forming liquid dispersions of nanomaterials typically focus on retarding reaggregation, for example via surface modification, as opposed to promoting the thermodynamically driven dissolution common for molecule-sized species. Here we demonstrate the true dissolution of a wide range of important 2D nanomaterials by forming layered material salts that spontaneously dissolve in polar solvents yielding ionic solutions. The benign dissolution advantageously maintains the morphology of the starting material, is stable against reaggregation and can achieve solutions containing exclusively individualized monolayers. Importantly, the charge on the anionic nanosheet solutes is reversible, enables targeted deposition over large areas via electroplating and can initiate novel self-assembly upon drying. Our findings thus reveal a unique solution-like behaviour for 2D materials that enables their scalable production and controlled manipulation.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Figure 1: Structure, dissolution and deposition of layered material salts.
Figure 2: The morphology of dissolved nanosheets.
Figure 3: Structure and self-assembly of dissolved nanosheets.
Figure 4: Electroplating a nanosheet solution.

References

  1. 1

    Nicolosi, V., Chowalla, M., Kanatzidis, M. G., Strano, M. S. & Coleman, J. N. Liquid exfoliation of layered materials. Science 340, 1226419 (2013).

    Article  Google Scholar 

  2. 2

    Ferrari, A. C. et al. Science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems. Nanoscale 7, 4598–4810 (2015).

    CAS  Article  Google Scholar 

  3. 3

    Stankovich, S. et al. Synthesis of graphene-based nanosheets via chemical reduction of exfoliated graphite oxide. Carbon 45, 1558–1565 (2007).

    CAS  Article  Google Scholar 

  4. 4

    Hummelen, J. C. et al. Preparation and characterization of fulleroid and methanofullerene derivatives. J. Org. Chem. 60, 532–538 (1995).

    CAS  Article  Google Scholar 

  5. 5

    Sperling, R. A. & Parak, W. J. Surface modification, functionalization and bioconjugation of colloidal inorganic nanoparticles. Phil. Trans. R. Soc. A 368, 1333–1383 (2010).

    CAS  Article  Google Scholar 

  6. 6

    Zobel, M., Neder, R. B. & Kimber, S. A. Universal solvent restructuring induced by colloidal nanoparticles. Science 347, 292–294 (2015).

    CAS  Article  Google Scholar 

  7. 7

    Boles, M. A., Ling, D., Hyeon, T. & Talapin, D. V. The surface science of nanocrystals. Nat. Mat. 15, 141–153 (2016).

    CAS  Article  Google Scholar 

  8. 8

    Lotya, M. et al. Liquid phase production of graphene by exfoliation of graphite in surfactant/water solutions. J. Am. Chem. Soc. 131, 3611–3620 (2009).

    CAS  Article  Google Scholar 

  9. 9

    Paton, K. R. et al. Scalable production of large quantities of defect-free few-layer graphene by shear exfoliation in liquids. Nat. Mater. 13, 624–630 (2014).

    CAS  Article  Google Scholar 

  10. 10

    Shih, C. J. et al. Bi-and trilayer graphene solutions. Nat. Nanotech. 6, 439–445 (2011).

    CAS  Article  Google Scholar 

  11. 11

    Coleman, J. N. et al. Two-dimensional nanosheets produced by liquid exfoliation of layered materials. Science 331, 568–571 (2011).

    CAS  Article  Google Scholar 

  12. 12

    Huo, C., Yan, Z., Song, X. & Zeng, H. 2D materials via liquid exfoliation: a review on fabrication and applications. Sci. Bull. 60, 1994–2008 (2015).

    CAS  Article  Google Scholar 

  13. 13

    Ma, R. & Sasaki, T. Two-dimensional oxide and hydroxide nanosheets: controllable high-quality exfoliation, molecular assembly, and exploration of functionality. Acc. Chem. Res. 48, 136–143 (2015).

    CAS  Article  Google Scholar 

  14. 14

    Stöter, M., Rosenfeldt, S. & Breu, J. Tunable exfoliation of synthetic clays. Annu. Rev. Mater. Res. 45, 129–151 (2015).

    Article  Google Scholar 

  15. 15

    Batista, C. A. S., Larson, R. G. & Kotov, N. A. Nonadditivity of nanoparticle interactions. Science 350, 6257 (2015).

    Google Scholar 

  16. 16

    Howard, C. A., Thompson, H., Wasse, J. C. & Skipper, N. T. Formation of giant solvation shells around fulleride anions in liquid ammonia. J. Am. Chem. Soc. 126, 13228–13229 (2004).

    CAS  Article  Google Scholar 

  17. 17

    Mezger, M. et al. Molecular layering of fluorinated ionic liquids at a charged sapphire (0001) surface. Science 322, 424–428 (2008).

    CAS  Article  Google Scholar 

  18. 18

    Burgess, J. Ions in Solution: Basic Principles of Chemical Interactions 2nd edn (Horwood, 1999).

  19. 19

    Joensen, P., Frindt, R. F. & Morrison, S. R. Single-layer MoS2 . Mater. Res. Bull. 21, 457–461 (1986).

    CAS  Article  Google Scholar 

  20. 20

    Eda, G. et al. Photoluminescence from chemically exfoliated MoS2 . Nano Lett. 11, 5111–5116 (2011).

    CAS  Article  Google Scholar 

  21. 21

    Lu, X. et al. Preparation of MoO3 QDs through combining intercalation and thermal exfoliation. J. Mat. Chem. C 4, 6720 (2016).

    CAS  Article  Google Scholar 

  22. 22

    Schaak, R. E. & Mallouk, T. E. Prying apart ruddlesden-popper phases: exfoliation into sheets and nanotubes for assembly of perovskite thin films. Chem. Mater. 12, 3427–3434 (2000).

    CAS  Article  Google Scholar 

  23. 23

    Sasaki, T., Watanabe, M., Hashizume, H., Yamada, H. & Nakazawa, H. Macromolecule-like aspects for a colloidal suspension of an exfoliated titanate. Pairwise association of nanosheets and dynamic reassembling process initiated from it. J. Am. Chem. Soc. 118, 8329–8335 (1996).

    CAS  Article  Google Scholar 

  24. 24

    Sposito, G. et al. Surface geochemistry of the clay minerals. Proc. Natl Acad. Sci. USA 96, 3358–3364 (1999).

    CAS  Article  Google Scholar 

  25. 25

    Dresselhaus, M. S. & Dresselhaus, G. Intercalation compounds of graphite. Adv. Phys. 51, 1–186 (2002).

    CAS  Article  Google Scholar 

  26. 26

    Fan, X. et al. Controlled exfoliation of MoS2 crystals into trilayer nanosheets. J. Am. Chem. Soc. 138, 5143–5149 (2016).

    CAS  Article  Google Scholar 

  27. 27

    Ding, Z., Viculis, L., Nakawatase, J. & Kaner, R. B. Intercalation and solution processing of bismuth telluride and bismuth selenide. Adv. Mater. 13, 797–800 (2001).

    CAS  Article  Google Scholar 

  28. 28

    Zeng, Z. et al. Single layer semiconducting nanosheets: high-yield preparation and device fabrication. Angew. Chem. Int. Ed. 50, 11093–11097 (2011).

    CAS  Article  Google Scholar 

  29. 29

    Vallés, C. et al. Solutions of negatively charged graphene sheets and ribbons. J. Am. Chem. Soc. 130, 15802–15804 (2008).

    Article  Google Scholar 

  30. 30

    Milner, E. M. et al. Structure and morphology of charged graphene platelets in solution by small-angle neutron scattering. J. Am. Chem. Soc. 134, 8302–8305 (2012).

    CAS  Article  Google Scholar 

  31. 31

    Huang, K. et al. Single layer nano graphene platelets derived from graphite nanofibres. Nanoscale 8, 8810 (2016).

    CAS  Article  Google Scholar 

  32. 32

    Pan, Z.-H. et al. Electronic structure of superconducting KC8 and nonsuperconducting LiC6 graphite intercalation compounds: evidence for a graphene-sheet-driven superconducting state. Phys. Rev. Lett. 106, 187002 (2011).

    Article  Google Scholar 

  33. 33

    Somoano, R. B., Hadek, V. & Rembaum, A. Alkali metal intercalates of molybdenum disulfide. J. Chem. Phys. 58, 697–701 (1973).

    CAS  Article  Google Scholar 

  34. 34

    Picco, L. M. et al. Breaking the speed limit with atomic force microscopy. Nanotechnology 18, 044030 (2006).

    Article  Google Scholar 

  35. 35

    Zeng, Z., Tan, C., Huang, X., Bao, S. & Zhang, H. Growth of noble metal nanoparticles on single-layer TiS2 and TaS2 nanosheets for hydrogen evolution reaction. Energy Environ. Sci. 7, 797 (2014).

    CAS  Article  Google Scholar 

  36. 36

    Lui, C. H., Liu, L., Mak, K. F., Flynn, G. W. & Heinz, T. F. Ultraflat graphene. Nature 462, 339–341 (2009).

    CAS  Article  Google Scholar 

  37. 37

    Tonndorf, P. et al. Photoluminescence emission and Raman response of monolayer MoS2, MoSe2, and WSe2 . Opt. Express 21, 4908–4916 (2013).

    CAS  Article  Google Scholar 

  38. 38

    Yoon, G. et al. Factors affecting the exfoliation of graphite intercalation compounds for graphene synthesis. Chem. Mater. 27, 2067–2073 (2015).

    CAS  Article  Google Scholar 

  39. 39

    Payton, O. D. et al. Experimental observation of contact mode cantilever dynamics with nanosecond resolution. Rev. Sci. Instrum. 82, 043704 (2011).

    CAS  Article  Google Scholar 

  40. 40

    Kodera, N., Yamamoto, D., Ishikawa, R. & Ando, T. Video imaging of walking myosin V by high-speed atomic force microscopy. Nature 468, 72–76 (2010).

    CAS  Article  Google Scholar 

Download references

Acknowledgements

This publication was funded, in part, by the Engineering & Physical Sciences Research Council (EPSRC). L.P. & O.D.P. thank the Royal Academy of Engineering for funding the development of the HS-AFM and the NSQI Low Noise Lab for hosting the HS-AFM. We thank Martial Duchamp for his valuable assistance with the ‘PICO’ TEM at the Ernst–Ruska Research Centre. The authors are grateful to Milo Shaffer & Paul McMillan for helpful and supportive discussions.

Author information

Affiliations

Authors

Contributions

C.A.H. and P.L.C. conceived the project. P.L.C., V.T., M.K.B.S., K.M.C. and C.A.H. made the intercalated compounds and solutions. M.K.B.S., K.M.C., P.L.C. & C.A.H. carried out X-ray analysis. L.P., O.D.P., P.L.C., K.M.C. and C.A.H. performed and analysed the AFM measurements. L.P. wrote the automated HS-AFM platelet detection and step height measurement algorithms. V.T. performed S/TEM and contributed to the analysis of the results. C.A.H. carried out the electroplating and Raman experiment. C.A.H. directed the study and wrote the paper. All authors discussed and developed the science and commented on the manuscript.

Corresponding author

Correspondence to Christopher A. Howard.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary information

Supplementary information (PDF 13917 kb)

Supplementary movie

Supplementary movie 1 (MP4 14021 kb)

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Cullen, P., Cox, K., Bin Subhan, M. et al. Ionic solutions of two-dimensional materials. Nature Chem 9, 244–249 (2017). https://doi.org/10.1038/nchem.2650

Download citation

Further reading

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing