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.

  • Article
  • Published:

On-liquid-gallium surface synthesis of ultrasmooth thin films of conductive metal–organic frameworks

Abstract

Conductive metal–organic frameworks (MOFs) are emerging electroactive materials for (opto)electronics; however, it is challenging to achieve MOF-based devices using existing synthesis methods. Here we develop an on-liquid-gallium surface synthesis (OLGSS) strategy under chemical vapour deposition conditions for the controlled growth of two-dimensional conjugated MOF (2D c-MOF) thin films, which gives a tenfold improvement in surface flatness compared with traditionally synthesized c-MOFs. The basis for constructing these flatter surfaces is a layer-by-layer chemical vapour deposition growth mode, which is triggered by the high adhesion energy between gallium and aromatic ligands. We demonstrate the generality of the OLGSS strategy by reproducing flat surfaces for nine different 2D c-MOF films with variable thicknesses (2–208 nm). Compared to traditionally synthesized MOF films, the resultant ultrasmooth films enable the formation of high-quality electrical contacts with contact resistance reduced by over 13-fold. Furthermore, due to the efficient interfacial interaction, the prepared van der Waals heterostructure of OLGSS c-MOF and MoS2 shows intriguing photoluminescence enhancement, photoluminescence peak shift and work function modulation. This robust OLGSS method provides the opportunity to develop MOF electronics and shows promise for the construction of multicomponent MOF-based heterostructure materials.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Schematic illustration of the synthesis of 2D c-MOF films on different substrates by CVD.
Fig. 2: OLGSS 2D c-MOF thin films with an ultrasmooth surface.
Fig. 3: Surface evenness of 2D c-MOF thin films synthesized by different methods.
Fig. 4: Growth mechanism behind the OLGSS strategy with O-Cu-BHT 2D c-MOF as a typical example.
Fig. 5: Interfacial contact of microelectronic devices based on various 2D c-MOF thin films.
Fig. 6: OLGSS thin-film-based vdWHs.

Similar content being viewed by others

Data availability

The data supporting the findings of the study are available in the paper and its Supplementary Information. Source data are provided with this paper.

References

  1. Talin, A. A. et al. Tunable electrical conductivity in metal–organic framework thin-film devices. Science 343, 66–69 (2014).

    Article  CAS  PubMed  Google Scholar 

  2. Schneider, C. et al. High electrical conductivity and high porosity in a Guest@MOF material: evidence of TCNQ ordering within Cu3BTC2 micropores. Chem. Sci. 9, 7405–7412 (2018).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  3. Liu, J. et al. Photoinduced charge-carrier generation in epitaxial MOF thin films: high efficiency as a result of an indirect electronic band gap? Angew. Chem. Int. Ed. 54, 7441–7445 (2015).

    Article  CAS  Google Scholar 

  4. Sun, L., Miyakai, T., Seki, S. & Dincă, M. Mn2(2,5-Disulfhydrylbenzene-1,4-dicarboxylate): a microporous metal–organic framework with infinite (–Mn–S–) chains and high intrinsic charge mobility. J. Am. Chem. Soc. 135, 8185–8188 (2013).

    Article  CAS  PubMed  Google Scholar 

  5. Wang, M., Dong, R. & Feng, X. Two-dimensional conjugated metal–organic frameworks (2Dc-MOFs): chemistry and function for MOFtronics. Chem. Soc. Rev. 50, 2764–2793 (2021).

    Article  CAS  PubMed  Google Scholar 

  6. Liu, J., Chen, Y., Feng, X. & Dong, R. Conductive 2D conjugated metal–organic framework thin films: synthesis and functions for (opto-)electronics. Small Struct. 3, 2100210 (2022).

    Article  CAS  Google Scholar 

  7. Sun, L., Campbell, M. G. & Dincă, M. Electrically conductive porous metal–organic frameworks. Angew. Chem. Int. Ed. 55, 3566–3579 (2016).

    Article  CAS  Google Scholar 

  8. Xie, L. S., Skorupskii, G. & Dincă, M. Electrically conductive metal–organic frameworks. Chem. Rev. 120, 8536–8580 (2020).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  9. Huang, X. et al. A two-dimensional πd conjugated coordination polymer with extremely high electrical conductivity and ambipolar transport behaviour. Nat. Commun. 6, 7408 (2015).

    Article  CAS  PubMed  Google Scholar 

  10. Dong, R. et al. A coronene-based semiconducting two-dimensional metal–organic framework with ferromagnetic behavior. Nat. Commun. 9, 2637 (2018).

    Article  PubMed  PubMed Central  Google Scholar 

  11. Chen, S., Dai, J. & Zeng, X. C. Metal-organic Kagome lattices M3(2,3,6,7,10,11-hexaiminotriphenylene)2 (M = Ni and Cu): from semiconducting to metallic by metal substitution. Phys. Chem. Chem. Phys. 17, 5954–5958 (2015).

    Article  CAS  PubMed  Google Scholar 

  12. Dong, R. et al. High-mobility band-like charge transport in a semiconducting two-dimensional metal–organic framework. Nat. Mater. 17, 1027–1032 (2018).

    Article  CAS  PubMed  Google Scholar 

  13. Arora, H. et al. Demonstration of a broadband photodetector based on a two-dimensional metal–organic framework. Adv. Mater. 32, 1907063 (2020).

    Article  CAS  Google Scholar 

  14. Sun, L. et al. A microporous and naturally nanostructured thermoelectric metal–organic framework with ultralow thermal conductivity. Joule 1, 168–177 (2017).

    Article  CAS  Google Scholar 

  15. Huang, X. et al. Superconductivity in a copper(II)-based coordination polymer with perfect kagome structure. Angew. Chem. Int. Ed. 57, 146–150 (2018).

    Article  CAS  Google Scholar 

  16. Wang, Z. F., Su, N. & Liu, F. Prediction of a two-dimensional organic topological insulator. Nano Lett. 13, 2842–2845 (2013).

    Article  CAS  PubMed  Google Scholar 

  17. Liu, J. & Wöll, C. Surface-supported metal–organic framework thin films: fabrication methods, applications, and challenges. Chem. Soc. Rev. 46, 5730–5770 (2017).

    Article  CAS  PubMed  Google Scholar 

  18. Wang, M. et al. Phthalocyanine-based 2D conjugated metal–organic framework nanosheets for high-performance micro-supercapacitors. Adv. Funct. Mater. 30, 2002664 (2020).

    Article  CAS  Google Scholar 

  19. Wang, Z. et al. Interfacial synthesis of layer-oriented 2D conjugated metal–organic framework films toward directional charge transport. J. Am. Chem. Soc. 143, 13624–13632 (2021).

    Article  CAS  PubMed  Google Scholar 

  20. Dong, R. et al. Large-area, free-standing, two-dimensional supramolecular polymer single-layer sheets for highly efficient electrocatalytic hydrogen evolution. Angew. Chem. Int. Ed. 54, 12058–12063 (2015).

    Article  CAS  Google Scholar 

  21. Wang, L., Sahabudeen, H., Zhang, T. & Dong, R. Liquid-interface-assisted synthesis of covalent–organic and metal–organic two-dimensional crystalline polymers. Npj 2D Mater. Appl. 2, 26 (2018).

    Article  Google Scholar 

  22. Su, P., Tu, M., Ameloot, R. & Li, W. Vapor-phase processing of metal–organic frameworks. Acc. Chem. Res. 55, 186–196 (2022).

    Article  CAS  PubMed  Google Scholar 

  23. Stassen, I. et al. Chemical vapour deposition of zeolitic imidazolate framework thin films. Nat. Mater. 15, 304–310 (2016).

    Article  CAS  PubMed  Google Scholar 

  24. Zeng, M. et al. Bandgap tuning of two-dimensional materials by sphere diameter engineering. Nat. Mater. 19, 528–533 (2020).

    Article  CAS  PubMed  Google Scholar 

  25. Choe, M. et al. Chemical vapor deposition of edge-on oriented 2D conductive metal–organic framework thin films. J. Am. Chem. Soc. 144, 16726–16731 (2022).

    Article  CAS  PubMed  Google Scholar 

  26. Ogle, J. et al. Semiconducting to metallic electronic landscapes in defects-controlled 2D πd conjugated coordination polymer thin films. Adv. Funct. Mater. 31, 2006920 (2021).

    Article  CAS  Google Scholar 

  27. Rubio-Giménez, V. et al. Chemical vapor deposition and high-resolution patterning of a highly conductive two-dimensional coordination polymer film. J. Am. Chem. Soc. 145, 152–159 (2023).

    Article  PubMed  Google Scholar 

  28. Berro, Y. et al. Atomistic description of phenol, CO and H2O adsorption over crystalline and amorphous silica surfaces for hydrodeoxygenation applications. Appl. Surf. Sci. 494, 721–730 (2019).

    Article  CAS  Google Scholar 

  29. Jiang, B., Yang, Z., Liu, X., Liu, Y. & Liao, L. Interface engineering for two-dimensional semiconductor transistors. Nano Today 25, 122–134 (2019).

    Article  CAS  Google Scholar 

  30. Fahlman, M. et al. Interfaces in organic electronics. Nat. Rev. Mater. 4, 627–650 (2019).

    Article  CAS  Google Scholar 

  31. Rubio-Giménez, V. et al. Bottom-up fabrication of semiconductive metal–organic framework ultrathin films. Adv. Mater. 30, 1704291 (2018).

    Article  Google Scholar 

  32. Song, X. et al. 2D semiconducting metal–organic framework thin films for organic spin valves. Angew. Chem. Int. Ed. 59, 1118–1123 (2020).

    Article  CAS  Google Scholar 

  33. Mahringer, A. et al. Oriented thin films of electroactive triphenylene catecholate-based two-dimensional metal organic frameworks. ACS Nano 13, 6711–6719 (2019).

    Article  PubMed  Google Scholar 

  34. Yao, M. S. et al. Layer-by-layer assembled conductive metal–organic framework nanofilms for room-temperature chemiresistive sensing. Angew. Chem. Int. Ed. 56, 16510–16514 (2017).

    Article  CAS  Google Scholar 

  35. Chen, Y. et al. Growth of 2D GaN single crystals on liquid metals. J. Am. Chem. Soc. 140, 16392–16395 (2018).

    Article  CAS  PubMed  Google Scholar 

  36. Liu, J. & Fu, L. Controllable growth of graphene on liquid surfaces. Adv. Mater. 31, 1800690 (2018).

    Article  Google Scholar 

  37. Wundrack, S. et al. Liquid metal intercalation of epitaxial graphene: large-area gallenene layer fabrication through gallium self-propagation at ambient conditions. Phys. Rev. Mater. 5, 024006 (2021).

    Article  CAS  Google Scholar 

  38. Lu, W. et al. Controllable sliding transfer of wafer-size graphene. Adv. Sci. 3, 1600006 (2016).

    Article  Google Scholar 

  39. Huang, X. et al. Highly conducting organic–inorganic hybrid copper sulfides CuxC6S6 (x = 4 or 5.5): ligand-based oxidation-induced chemical and electronic structure modulation. Angew. Chem. Int. Ed. 132, 22791–22798 (2020).

    Article  Google Scholar 

  40. Amores, M., Wada, K., Sakaushi, K. & Nishihara, H. Reversible energy storage in layered copper-based coordination polymers: unveiling the influence of the ligand’s functional group on their electrochemical properties. J. Phys. Chem. C 124, 9215–9224 (2020).

    Article  CAS  Google Scholar 

  41. Virkar, A. A., Mannsfeld, S., Bao, Z. & Stingelin, N. Organic semiconductor growth and morphology considerations for organic thin-film transistors. Adv. Mater. 22, 3857–3875 (2010).

    Article  CAS  PubMed  Google Scholar 

  42. Chen, Y. et al. Universal growth of ultra-thin III–V semiconductor single crystals. Nat. Commun. 11, 3979 (2020).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  43. Kappera, R. et al. Phase-engineered low-resistance contacts for ultrathin MoS2 transistors. Nat. Mater. 13, 1128–1134 (2014).

    Article  CAS  PubMed  Google Scholar 

  44. Mouri, S., Miyauchi, Y. & Matsuda, K. Tunable photoluminescence of monolayer MoS2 via chemical doping. Nano Lett. 13, 5944–5948 (2013).

    Article  CAS  PubMed  Google Scholar 

  45. Mak, K. F., Lee, C., Hone, J., Shan, J. & Heinz, T. F. Atomically thin MoS2: a new direct-gap semiconductor. Phys. Rev. Lett. 105, 136805 (2010).

    Article  PubMed  Google Scholar 

  46. Mawlong, L. P. L., Paul, K. K. & Giri, P. K. Direct chemical vapor deposition growth of monolayer MoS2 on TiO2 nanorods and evidence for doping-induced strong photoluminescence enhancement. J. Phys. Chem. C 122, 15017–15025 (2018).

    Article  CAS  Google Scholar 

  47. Wang, F. et al. Configuration-dependent electrically tunable van der Waals heterostructures based on MoTe2/MoS2. Adv. Funct. Mater. 26, 5499–5506 (2016).

    Article  CAS  Google Scholar 

  48. Kim, G.-S. et al. Schottky barrier height engineering for electrical contacts of multilayered MoS2 transistors with reduction of metal-induced gap states. ACS Nano 12, 6292–6300 (2018).

    Article  CAS  PubMed  Google Scholar 

  49. Zhou, J. et al. A library of atomically thin metal chalcogenides. Nature 556, 355–359 (2018).

    Article  CAS  PubMed  Google Scholar 

  50. Kresse, G. & Furthmüller, J. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B 54, 11169–11186 (1996).

    Article  CAS  Google Scholar 

  51. Kresse, G. & Furthmüller, J. Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set. Comput. Mater. Sci. 6, 15–50 (1996).

    Article  CAS  Google Scholar 

  52. Perdew, J. P., Burke, K. & Ernzerhof, M. Generalized gradient approximation made simple. Phys. Rev. Lett. 77, 3865–3868 (1996).

    Article  CAS  PubMed  Google Scholar 

  53. Grimme, S., Antony, J., Ehrlich, S. & Krieg, H. A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H–Pu. J. Chem. Phys. 132, 154104 (2010).

    Article  PubMed  Google Scholar 

  54. Assael, M. J. et al. Reference data for the density and viscosity of liquid cadmium, cobalt, gallium, indium, mercury, silicon, thallium, and zinc. J. Phys. Chem. Ref. Data 41, 033101 (2012).

    Article  Google Scholar 

  55. Ballirano, P., Maras, A., Marchetti, F., Merlino, S. & Perchiazzi, N. Rietveld refinement of chapmanite SbFe2Si2O8OH, a TO dioctahedral kaolinite-like mineral. Powder Diffr. 13, 44–49 (1998).

    Article  CAS  Google Scholar 

  56. Jones, L. et al. Smart Align—a new tool for robust non-rigid registration of scanning microscope data. Adv. Struct. Chem. Imaging 1, 8 (2015).

    Article  Google Scholar 

Download references

Acknowledgements

This work was financially supported by National Natural Science Foundation of China (22272092), ERC starting grant (FC2DMOF, number 852909), ERC Consolidator grant (T2DCP), SFB-1415 (number 417590517), GRK2861 (number 491865171), EMPIR-20FUN03-COMET, and by the German Science Council, Center for Advancing Electronics Dresden (CFAED). This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (ERC grant agreement number 714067, ENERGYMAPS). We acknowledge the European Synchrotron Radiation Facility (ESRF) for provision of synchrotron radiation facilities and we thank O. Konovalov for assistance and support in using beamline ID10. We acknowledge Elettra Sincrotrone Trieste for providing access to its synchrotron radiation facilities and for financial support under the IUS internal project. We thank L. Barba for assistance in using beamline XRD1. We acknowledge Dresden Center for Nanoanalysis (DCN) at TUD. R.D. thanks the Taishan Scholars Program of Shandong Province (tsqn201909047) and the Natural Science Foundation of Shandong Province (ZR2023JQ005). We thank Z. Wang for his help with TEM measurements. J.L. gratefully acknowledges funding from the Alexander von Humboldt Foundation.

Author information

Authors and Affiliations

Authors

Contributions

R.D. and X.F. conceived this project. J.L. and Y.C. carried out the CVD growth experiments and the Raman, PL, AFM and SEM measurements, and the device fabrication. X.H. provided the BHT ligand. Y.R., D.B., A.D., J.G. and G.C. conducted the DFT calculations. M.D., F.Z, J.H. and Y.V. performed the XPS and UPS measurements and analysed the spectra. D.P., F.Z., X.L., B.Z. and Z.L. performed the TEM measurements. M.L. contributed to the SEM measurements. M.H. and S.C.B.M. performed the GIWAXS measurements and also contributed to the device measurements. J.L., Y.C., R.D. and X.F. co-wrote the manuscript with contributions from all the authors.

Corresponding authors

Correspondence to Junfeng Gao, Xinliang Feng or Renhao Dong.

Ethics declarations

Competing interests

The authors declare no competing interests.

Peer review

Peer review information

Nature Synthesis thanks Mark Allendorf, Ning Huang, Grigorii Skorupskii and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Primary Handling Editor: Alison Stoddart, in collaboration with the Nature Synthesis team.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Figs. 1–55 and Tables 1–3.

Source data

Source Data Fig. 3

Statistical source data of film roughness and thickness.

Source Data Fig. 5

Source sata of lateral and vertical devices.

Source Data Fig. 6

Source data of PL, UPS and c-AFM curves.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Liu, J., Chen, Y., Huang, X. et al. On-liquid-gallium surface synthesis of ultrasmooth thin films of conductive metal–organic frameworks. Nat. Synth (2024). https://doi.org/10.1038/s44160-024-00513-9

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1038/s44160-024-00513-9

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