Metallic conduction at organic charge-transfer interfaces
Source abstract
Abstract
The electronic properties of interfaces between two different solids can differ strikingly from those of the constituent materials. For instance, metallic conductivity-and even superconductivity-have recently been discovered at interfaces formed by insulating transition-metal oxides. Here, we investigate interfaces between crystals of conjugated organic molecules, which are large-gap undoped semiconductors, that is, essentially insulators. We find that highly conducting interfaces can be realized with resistivity ranging from 1 to 30 kohms per square, and that, for the best samples, the temperature dependence of the conductivity is metallic. The observed electrical conduction originates from a large transfer of charge between the two crystals that takes place at the interface, on a molecular scale. As the interface assembly process is simple and can be applied to crystals of virtually any conjugated molecule, the conducting interfaces described here represent the first examples of a new class of electronic systems.
Source: europepmc · Quality: candidate unverified · Source record ↗
Research context
OpenAlex topics: Electronic and Structural Properties of Oxides · Machine Learning in Materials Science · Electrochemical Analysis and Applications
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
References (37)
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1. Chiang, C. K. et al. Electrical conductivity in doped polyacetylene. Phys. Rev. Lett. 39, 1098–1101 (1977).10.1103/PhysRevLett.39.1098 ↗
2. Haddon, R. C. et al. Conducting films of C60 and C70 by alkali-metal doping. Nature 350, 320–322 (1991).10.1038/350320a0 ↗
3. Hebard, A. F. et al. Superconductivity at 18 K in potassium-doped C60 . Nature 350, 600–601 (1991).10.1038/350600a0 ↗
4. Jerome, D. & Schulz, H. J. Organic conductors and superconductors. Adv. Phys. 31, 299–490 (1982).10.1080/00018738200101398 ↗
5. Calhoun, M. F., Sanchez, J., Olaya, D., Gershenson, M. E. & Podzorov, V. Electronic functionalization of the surface of organic semiconductors with self-assembled monolayers. Nature Mater. 7, 84–89 (2008).10.1038/nmat2059 ↗
6. Ohtomo, A. & Hwang, H. Y. A high-mobility electron gas at the LaAlO3/SrTiO3 heterointerface. Nature 427, 423–426 (2004).10.1038/nature02308 ↗
7. Reyren, N. et al. Superconducting interfaces between insulating oxides. Science 317, 1196–1199 (2007).10.1126/science.1146006 ↗
8. Brinkman, A. et al. Magnetic effects at the interface between non-magnetic oxides. Nature Mater. 6, 493–496 (2007).10.1038/nmat1931 ↗
9. Ferraris, J., Walatka, V., Perlstei, J. H. & Cowan, D. O. Electron-transfer in a new highly-conducting donor–acceptor complex. J. Am. Chem. Soc. 95, 948–949 (1973).10.1021/ja00784a066 ↗
10. Jerome, D. Organic conductors: from charge density wave TTF–TCNQ to superconducting (TMTSF)2PF6 . Chem. Rev. 104, 5565–5591 (2004).10.1021/cr030652g ↗
11. Ishiguro, T., Yamaji, K. & Saito, G. Organic Superconductors 2nd edn (Springer, Berlin, 1998).10.1007/978-3-642-58262-2 ↗
12. Silinsh, E. A. & Capek, V. Organic Molecular Crystals (American Institute of Physics, New York, 1994).
13. Farges, J. P. & Brau, A. Electrical properties of powdered or pure TCNQ and TTF: Evidence for a strong solid-state charge-transfer reaction. Physica 143B, 324–326 (1986).
14. de Boer, R. W. I., Gershenson, M. E., Morpurgo, A. F. & Podzorov, V. Organic single-crystal field-effect transistors. Phys. Status Solidi. A 201, 1302–1331 (2004).10.1002/pssa.200404336 ↗
15. Aleshin, A. N., Lee, J. Y., Chu, S. W., Kim, J. S. & Park, Y. W. Mobility studies of field-effect transistor structures based on anthracene single crystals. Appl. Phys. Lett. 84, 5383–5385 (2004).10.1063/1.1767282 ↗
16. de Boer, R. W. I., Klapwijk, T. M. & Morpurgo, A. F. Field-effect transistors on tetracene single crystals. Appl. Phys. Lett. 83, 4345–4347 (2003).10.1063/1.1629144 ↗
17. Takeya, J. et al. Field-induced charge transport at the surface of pentacene single crystals: A method to study charge dynamics of two dimensional electron systems in organic crystals. J. Appl. Phys. 94, 5800–5804 (2003).10.1063/1.1618919 ↗
18. Hulea, I. N. et al. Tunable Frohlich polarons in organic single-crystal transistors. Nature Mater. 5, 982–986 (2006).10.1038/nmat1774 ↗
19. de Boer, R. W. I. et al. Ambipolar Cu- and Fe-phthalocyanine single-crystal field-effect transistors. Appl. Phys. Lett. 86, 262109 (2005).10.1063/1.1984093 ↗
20. Horowitz, G., Garnier, F., Yassar, A., Hajlaoui, R. & Kouki, F. Field-effect transistor made with a sexithiophene single crystal. Adv. Mater. 8, 52–54 (1996).10.1002/adma.19960080109 ↗
21. Sundar, V. C. et al. Elastomeric transistor stamps: Reversible probing of charge transport in organic crystals. Science 303, 1644–1646 (2004).10.1126/science.1094196 ↗
22. Molinari, A., Gutierrez, I., Hulea, I. N., Russo, S. & Morpurgo, A. F. Bias-dependent contact resistance in rubrene single-crystal field-effect transistors. Appl. Phys. Lett. 90, 212103 (2007).10.1063/1.2741411 ↗
23. Takahasi, T., Takenobu, T., Takeya, J. & Iwasa, Y. Ambipolar organic field-effect transistors based on rubrene single crystals. Appl. Phys. Lett. 88, 033505 (2006).10.1063/1.2166698 ↗
24. Takeya, J., Yamagishi, M., Tominari, Y. & Nakazawa, Y. Gate dielectric materials for high-mobility organic transistors of molecular semiconductor crystals. Solid State Electron. 51, 1338–1343 (2007).10.1016/j.sse.2007.06.023 ↗
25. Menard, E. et al. Nanoscale surface morphology and rectifying behavior of a bulk single-crystal organic semiconductor. Adv. Mater. 18, 1552–1556 (2006).10.1002/adma.200502569 ↗
26. Gershenson, M. E., Podzorov, V. & Morpurgo, A. F. Electronic transport in single-crystal organic transistors. Rev. Mod. Phys. 78, 973–989 (2006).10.1103/RevModPhys.78.973 ↗
27. Hulea, I. N., Russo, S., Molinari, A. & Morpurgo, A. F. Reproducible low contact resistance in rubrene single-crystal field-effect transistors with nickel electrodes. Appl. Phys. Lett. 88, 113512 (2006).10.1063/1.2185632 ↗
28. Guo, D., Sakamoto, K., Miki, K., Ikeda, S. & Saiki, K. Orientation control of pentacene and transport anisotropy of the thin film transistor by photoaligned polyimide film. Appl. Phys. Lett. 90, 102117 (2007).10.1063/1.2711776 ↗
29. Lee, P. A. & Ramakrishnan, T. V. Disordered electronic systems. Rev. Mod. Phys. 57, 287–337 (1985).10.1103/RevModPhys.57.287 ↗
30. Fratini, S., Xie, H., Hulea, I. N., Ciuchi, S. & Morpurgo, A. F. Current saturation and Coulomb interactions in organic single-crystal transistors. New J. Phys. 10, 033031 (2008).10.1088/1367-2630/10/3/033031 ↗
31. Kobayashi, S. et al. Control of carrier density by self-assembled monolayers in organic field-effect transistors. Nature Mater. 3, 317–322 (2004).10.1038/nmat1105 ↗
32. Jerome, D., Rice, T. M. & Kohn, W. Excitonic insulator. Phys. Rev. 158, 462–475 (1967).10.1103/PhysRev.158.462 ↗
33. Laudise, R. A., Kloc, C., Simpkins, P. G. & Sigriest, T. Physical vapor growth of organic crystals. J. Cryst. Growth 187, 449–454 (1998).10.1016/S0022-0248(98)00034-7 ↗
34. Kistenmacher, T. J., Phillips, T. E. & Cowan, D. O. The crystal structure of the 1:1 radical cation-radical anion salt of 2-2′-bis-1,3-dithiole (TTF) and 7,7,8,8-tetracyanoquinodimethane (TCNQ). Acta Crystallogr. B 30, 763–768 (1974).10.1107/S0567740874003669 ↗
35. Cooper, W. F. et al. Crystal and molecular structure of aromatic sulphur compound 2,2′-bi-1,3-dithiole—evidence for d-orbital participation in bonding. J. Chem. Soc. D 16, 889–890 (1971).10.1039/C29710000889 ↗
36. Long, R. E., Sparks, R. A. & Trueblood, K. N. The crystal and molecular structure of 7,7,8,8-tetracyanoquinodimethane. Acta Crystallogr. 18, 932–939 (1965).10.1107/S0365110X65002256 ↗
37. Menard, E. et al. High-performance n- and p-type single-crystal organic transistors with free-space gate dielectrics. Adv. Mater. 16, 2097–2101 (2004).10.1002/adma.200401017 ↗