Abstract

Organic/metal interfaces control the performance of many optoelectronic organic devices, including organic light-emitting diodes or field-effect transistors. Using scanning tunnelling microscopy, low-energy electron diffraction, X-ray photoemission spectroscopy, near-edge X-ray absorption fine structure spectroscopy and density functional theory calculations, we show that electron transfer at the interface between a metal surface and the organic electron acceptor tetracyano-p-quinodimethane leads to substantial structural rearrangements on both the organic and metallic sides of the interface. These structural modifications mediate new intermolecular interactions through the creation of stress fields that could not have been predicted on the basis of gas-phase neutral tetracyano-p-quinodimethane conformation.

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References

  1. 1.

    The path to ubiquitous and low-cost organic electronic appliances on plastic. Nature 428, 911–918 (2004).

  2. 2.

    Conjugated polymer blends: linking film morphology to performance of light emitting diodes and photodiodes. J. Phys. Condens. Matter. 14, 12235–12260 (2002).

  3. 3.

    & Organic light emitting field effect transistors: advances and perspectives. Adv. Funct. Mater. 17, 3421–3434 (2007).

  4. 4.

    , , & Device physics of polymer:fullerene bulk heterojunction solar cells. Adv. Mater. 19, 1551–1566 (2007).

  5. 5.

    , & Plastic solar cells. Adv. Funct. Mater. 11, 15–26 (2001).

  6. 6.

    Organic conductors: from charge density wave TTF–TCNQ to superconducting (TMTSF)2PF6. Chem. Rev. 104, 5565–5591 (2004).

  7. 7.

    , , , & A room-temperature molecular/organic-based magnet. Science 252, 1415–1417 (1991).

  8. 8.

    et al. High-temperature metallorganic magnets. Nature 445, 291–294 (2007).

  9. 9.

    et al. Supramolecular control of the magnetic anisotropy in two-dimensional high-spin Fe arrays at a metal interface. Nature Mater. 104, 189–193 (2009).

  10. 10.

    Electronic structure and electron dynamics at molecule–metal interfaces: implications for molecule based electronics. Surf. Sci. Rep. 56, 1–83 (2004).

  11. 11.

    & Photoinduced electron transfer at molecule–metal interfaces. Chem. Rev. 106, 4281–4300 (2006).

  12. 12.

    et al. An organic donor/acceptor lateral superlattice at the nanoscale. Nano Lett. 7, 2602–2607 (2007).

  13. 13.

    , & Engineering atomic and molecular nanostructures at surfaces. Nature 437, 671–679 (2005).

  14. 14.

    , & Charge-transfer across the molecule/metal interface using the core hole clock technique. Surf. Sci. Rep. 63, 465–386 (2008).

  15. 15.

    , , & Energy level alignment and interfacial electronic structures at organic/metal and organic/organic interfaces. Adv. Mater. 11, 605–625 (1999).

  16. 16.

    et al. Characterization of the interface dipole at organic/metal interfaces. J. Am. Chem. Soc. 124, 8131–8141 (2002).

  17. 17.

    , , , & Optimized hole injection with strong electron acceptors at organic–metal interfaces. Phys. Rev. Lett. 95, 237601 (2005).

  18. 18.

    , , & Vacuum level alignment at organic/metal junctions: ‘cushion’ effect and the interface dipole. Appl. Phys. Lett. 87, 263502 (2005).

  19. 19.

    & Fermi level pinning at interfaces with tetrafluorotetracyanoquinodimethane (F4-TCNQ): the role of integer charge transfer states. Chem. Phys. Lett. 438, 259–262 (2007).

  20. 20.

    et al. Impact of bidirectional charge transfer and molecular distortions on the electronic structure of a metal–organic interface. Phys. Rev. Lett. 99, 256801 (2007).

  21. 21.

    , , & Strongly reshaped organic–metal interfaces: tetracyanoethylene on Cu(100). Phys. Rev. Lett. 101, 216105 (2008).

  22. 22.

    The difference between metallic and insulating salts of tetracyanoquinodimethane (TCNQ): how to design an organic metal. Acc. Chem. Res. 12, 79–86 (1979).

  23. 23.

    et al. Single-molecule charge transfer and bonding at an organic/inorganic interface: tetracyanoethylene on noble metals. Nano Lett. 8, 131–135 (2008).

  24. 24.

    , , & A theoretical study of neutral and reduced tetracyano-p-quinodimethane (TCNQ). J. Mol. Struct. 709, 97–102 (2004).

  25. 25.

    , , & Strong electronic perturbation of the Cu(111) surface by 7,7’,8,8’-tetracyanoquinonedimethane. Surf. Sci. 419, 12–23 (1998).

  26. 26.

    , & Structure and electronic configuration of tetracyanoquinodimethane layers on a Au(111) surface. Int. J. Mass Spectrosc. 277, 269–273 (2008).

  27. 27.

    & Determination of molecular orientations on surfaces from the angular dependence of near-edge X-ray-absorption fine-structure spectra. Phys. Rev. B 36, 7891–1905 (1987).

  28. 28.

    NEXAFS Spectroscopy (Spinger-Verlag, 2003).

  29. 29.

    et al. Near edge X-ray absorption fine structure resonances of quinoide molecules. Langmuir 16, 6674–6681 (2000).

  30. 30.

    et al. Structural versus electronic origin of renormalized band widths in TTF–TCNQ: an angular dependent NEXAFS study. Phys. Rev. B 76, 245119 (2007).

  31. 31.

    et al. Characterization of the unoccupied and partially occupied states of TTF–TCNQ by XANES and first-principles calculations. Phys. Rev. B 68, 195115 (2003).

  32. 32.

    Study of the geometry and electronic structure of self-assembled monolayers on the Au(111) surface. PhD thesis, Universidad del Pais Vasco (2009).

  33. 33.

    et al. Long-range spatial self-organization in the adsorbate-induced restructuring of surfaces: Cu(110)–(2×1)O. Phys. Rev. Lett. 67, 855–858 (1991).

  34. 34.

    et al. Size relation for surface systems with long-range interactions. Phys. Rev. Lett. 72, 2737–2740 (1994).

  35. 35.

    et al. Elastic origin of the O/Cu(110) self-ordering evidenced by GIXD. Surf. Sci. 549, 52–56 (2004).

  36. 36.

    et al. One-dimensional self-assembled molecular chains on Cu(100): interplay between surface-assisted coordination chemistry and substrate commensurability. J. Phys. Chem. C 111, 10982–10987 (2007).

  37. 37.

    Function follows form: exploring 2D supramolecular assembly at surfaces. ACS Nano 2, 617–621 (2008).

  38. 38.

    & Accurate and simple analytic representation of the electron–gas correlation energy. Phys. Rev. B 45, 13244–13249 (1992).

  39. 39.

    Projector augmented-wave method. Phys. Rev. B 50, 17953–17979 (1994).

  40. 40.

    & From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B 59, 1758–1775 (1999).

  41. 41.

    & High-precision sampling for Brillouin-zone integration in metals. Phys. Rev. B 40, 3616–3621 (1989).

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Acknowledgements

Studies at MPI Stuttgart were supported by the European Science Foundation (ESF) EUROCORES-SONS2 programme FunSMARTs II. Work in Madrid was financed by the Spanish MICINN (projects FIS2007-61114, FIS2007-60064, NAN2004-08881-C02-01, CTQ2006-08558 and Consolider CSD2007-00010), the Comunidad de Madrid (projects S-0505-MAT-0194 and S2009/MAT-1726) and the European Union (‘MONET’ project, MEST-CT-2005-020908). R.O. thanks the MEC for salary support through the Ramón & Cajal programme. All the computations were performed at Mare Nostrum Barcelona Supercomputer Center and Centro de Computación Científica de la UAM.

Author information

Affiliations

  1. Max Planck Institute for Solid State Research, D-70569 Stuttgart, Germany

    • Tzu-Chun Tseng
    • , Steven L. Tait
    • , Nian Lin
    • , Mitsuharu Konuma
    • , Ulrich Starke
    • , Alexander Langner
    •  & Klaus Kern
  2. Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain

    • Christian Urban
    • , Roberto Otero
    • , David Écija
    • , Marta Trelka
    •  & Rodolfo Miranda
  3. Departamento de Química, Universidad Autónoma de Madrid, 28049 Madrid, Spain

    • Yang Wang
    • , Manuel Alcamí
    •  & Fernando Martín
  4. Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Cantoblanco, 28049 Madrid, Spain

    • Roberto Otero
    • , Nazario Martín
    •  & Rodolfo Miranda
  5. Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA

    • Steven L. Tait
  6. Instituto de Ciencia de Materiales de Madrid - CSIC, Cantoblanco, 28049 Madrid, Spain

    • José María Gallego
  7. Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China

    • Nian Lin
  8. Lehrstuhl für Physikalische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany

    • Alexei Nefedov
  9. Institute of Functional Interfaces, Karlsruhe Institute of Technology (KIT), 76012 Karlsruhe, Germany

    • Christof Wöll
  10. Departamento de Química Orgánica, Universidad Complutense de Madrid, 28040 Madrid, Spain

    • María Ángeles Herranz
    •  & Nazario Martín
  11. Institut de Physique de la Matière Condensée, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland

    • Klaus Kern

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Contributions

STM experiments were carried out by T.-C.T., C.U. and M.T. T.-C.T. and C.U. contributed equally to this work. T.-C.T., C.U. and D.E. were involved in STM data analysis. Y.W., M.A. and F.M. carried out the DFT calculations shown in this paper. T.-C.T., S. L.T., M.K. and U.S. performed the XPS and LEED measurements and analysis, and T.-C.T., A.L., S.L.T. and A.N. performed the NEXAFS experiments and analysis, supervised by C.W. The molecules were provided by M.A.H. and N.M. and they supervised the chemical discussions. R.O., J.M.G. and S.L.T. wrote the paper and coordinated all the experimental work. Experiments were planned and designed by R.O., J.M.G., S.L.T., U.S. and N.L. under the supervision of K.K. and R.M.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Roberto Otero or Steven L. Tait.

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https://doi.org/10.1038/nchem.591

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