Chemical and Electronic Structure of Interfaces with Conjugated Polymers: Systems of Interest in Molecular Electronics Applications

  • G. Iucci
  • K. Xing
  • C. W. Spangler
  • M. Lögdlund
  • A. Holmes
  • W. R. Salaneck


The doping of conjugated polymers by electronic oxidation or reduction leads to the high electrical conductivity of conducting polymers. In the doping process, electronic charge is transferred either to (reduction) or from (oxidation) the conjugated polymer. The electrons transferred are stored in new electronic states, the energies of which fall with in the otherwise forbidden electron energy gap of the pristine (undoped) polymer. In polymers with a degenerate ground state, such as polyacetylene, spinless charged solitons are formed, while for polymers having a non-degenerate ground state, such as poly(para-phenylenevinylene), the charges are accommodated in singly-charged polarons or doubly-charged spinless bipolarons [1,2]. In this work, n-type doping is studied, since the addition of electrons can be studied by photoelectron spectroscopy, where added holes (the absence of electrons) is more difficult. In the doping of non-degenerate ground state polymers, the very first electrons go into polaron states. As the number of polarons increases, with increased doping, bipolarons may be formed, depending upon which form of charge storage species has the lowest energy in the particular polymer system, and a polaron-bipolaron transition takes place.


Sodium Atom Ultraviolet Photoelectron Spectroscopy Rubidium Atom Polaron State Bipolaron State 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    “Handbook of Conducting Polymers”, T. A. Skotheim, ed., Markel Dekker, New York (1986).Google Scholar
  2. 2.
    “Conjugated Polymers: The Novel Science and Technology of Highly Conducting and Nonlinear Optically Active Materials”, J. L. Brédas and R. Silbey, ed., Kluwer, Dordrecht (1991).Google Scholar
  3. 3.
    J. H. Burroughes, D. D. C. Bradley, A. R. Brown, R. N. Marks, K. Mackay, R. H. Friend, P. L. Burns and A. B. Holmes, Light-emitting diodes based on conjugated polymers, Nature 347:539 (1990).CrossRefGoogle Scholar
  4. 4.
    P. Dannetun, M. Lögdlund, W. R. Salaneck, C. Fredriksson, S. Stafström, A. B. Holmes, A. Brown, S. Graham, R. H. Friend and O. Lhost, New results on metal-polymer interfaces, Mol. Cryst Liq. Cryst. 228:43 (1993).CrossRefGoogle Scholar
  5. 5.
    T. P. Nguyen, V. Massardier, V. H. Tran and A. Guyot, Studies of the polymer-metal interface in metal-ppv-metal devices, Synth. Met. 55–57:235 (1993).CrossRefGoogle Scholar
  6. 6.
    E. Ettedgui, H. Razafitrimo, K. T. Park, Y. Gao and B. R. Hsieh, An x-ray photoemission spectroscopy study of the role of sample preparation on band bending at the interface of Al with poly(p-phenylenevinylene), J. Appl Phys. 75:7526 (1994).CrossRefGoogle Scholar
  7. 7.
    Y. Gao, K. T. Park and B. R. Hsieh, X-ray photoemission investigations of the interface formation of Ca and poly(p-phenylenevinylene), J. Chem. Phys. 97:6991 (1992).CrossRefGoogle Scholar
  8. 8.
    P. Dannetun, M. Fahlman, C. Fauquet, K. Kaerijama, Y. Sonoda, R. Lazzaroni, J. L. Brédas and W. R. Salaneck, Interface formation between poly(2,5-diheptyl-p- phenylenevinylene) and calcium: Implications for light emitting diodes, Synth. Met. 67:113 (1994).Google Scholar
  9. 9.
    W. R. Salaneck, S. Stafström and J. L. Brédas. “Conjugated Polymer Surfaces and Interfaces”, Cambridge University Press, Cambridge (1996).CrossRefGoogle Scholar
  10. 10.
    M. Fahlman, D. Beljonne, M. Lögdlund, R. H. Friend, A. B. Holmes, J. L. Brédas and W. R. Salaneck, Experimental and theoretical studies of the electronic structure of na-doped poly(p-phenylenevinylene), Chem. Phys. Lett. 214:327 (1993).CrossRefGoogle Scholar
  11. 11.
    P. Dannetun, M. Lögdlund, M. Fahlman, C. Fauquet, D. Beljonne, J. L. Brédas, H. Bässler and W. R. Salaneck, The evolution of charge-induced gap states in degenerate and non degenerate conjugated molecules and polymers as studied by photoelectron spectroscopy, Synth. Met. 67:81 (1994).CrossRefGoogle Scholar
  12. 12.
    P. Dannetun, M. Lögdlund, J. L. Brédas, C. W. Spangler and W. R. Salaneck, Evolution of charge-induced gap states in short diphenylpolyenes as studied by photoelectron spectroscopy, J. Phys. Chem. 98:2853 (1994).CrossRefGoogle Scholar
  13. 13.
    M. Lögdlund, P. Dannetun, S. Stafström, W. R. Salaneck, M. G. Ramsey, C. W. Spangler, C. Fredriksson and J. L. Brédas, Soliton pair charge storage in doped polyene molecules: evidence from photoelectron spectroscopy studies, Phys. Rev. Lett 70:970 (1993).CrossRefGoogle Scholar
  14. 14.
    P. Dannetun, M. Lögdlund, R. Lazzaroni, C. Fauquet, C. Fredriksson, S. Stafström, C. W. Spangler, J. L. Brédas and W. R. Salaneck, Reactions of low workfunction metals, na, al, and ca, on α, on α, ω-diphenyltetradecaheptaene: Implications for metal/polymer interfaces, J. Chem. Phys. 100:6765 (1994).CrossRefGoogle Scholar
  15. 15.
    M. J. S. Dewar, E. G. Zoebisch, E. F. Healy and J. J. P. Stewart, AMI: A new general purpose quantum mechanical molecular model., J. Am. Chem. Soc. 107:3902 (1985).CrossRefGoogle Scholar
  16. 16.
    J. L. Brédas, R. R. Chance, R. Silbey, G. Nicolas and P. Durand, A nonempirical effective Hamiltonian technique for polymers: Application to poly acetylene and polydiacetylene, J. Chem. Phys. 75:255 (1981).CrossRefGoogle Scholar
  17. 17.
    J. M. André, J. Delhalle and J. L. Brédas, “Quantum Chemistry Aided Design of Organic Polymers”, World Scientific, Singapore (1991).Google Scholar
  18. 18.
    J. L. Brédas, B. Thémans, J. G. Fripiat, J. M. André and R. R. Chance, Highly conducting polyparaphenylene, polypyrrole and polythiophene chains: An ab initio study of the geometry and electronic-structure modifications upon doping, Phys. Rev. B 29:6761 (1984).CrossRefGoogle Scholar
  19. 19.
    M. Fahlman, P. Bröms, D. A. dos Santos, S. C. Moratti, N. Johansson, K. Xing, R. H. Friend, A. B. Holmes, J. L. Brédas and W. R. Salaneck, Electronic structure of pristine and sodium-doped cyano-substituted poly(2,5-dihexyloxy-p- phenylenevinylene): A combined experimental and theoretical study, J. Chem. Phys., in press.Google Scholar
  20. 20.
    B. Rousseau and H. Estrade-Szwarckopf, Photoelectron core level spectroscopy study of K- and Rb-graphite intercalation compounds-II. Clean surface studies, Solid State Commun. 85:793 (1993).CrossRefGoogle Scholar
  21. 21.
    C. B. Duke, W. R. Salaneck, T. J. Fabish, J. J. Ritsko, H. R. Thomas and A. Paton, The electronic structure of pendant-group polymers: molecular ion states and dielectric properties of poly (2-vinyl pyridine), Phys. Rev. B, 18:5717 (1978).CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1995

Authors and Affiliations

  • G. Iucci
    • 1
  • K. Xing
    • 1
  • C. W. Spangler
    • 2
  • M. Lögdlund
    • 1
  • A. Holmes
    • 3
  • W. R. Salaneck
    • 1
  1. 1.Department of PhysicsLinköping UniversityLinköpingSweden
  2. 2.Department of ChemistryNorthern Illinois UniversityDeKalbUSA
  3. 3.Department of ChemistryUniversity of CambridgeCambridgeUK

Personalised recommendations