Abstract
Low temperature ESR spectra of cis-rich and trans-rich polyacetylene, lightly doped with pentafluorides (AsF5, SbF5) exhibit two clearly distinguishable ESR lines. Detailed studies of these two lines as a function of temperature, doping concentration and microwave power indicate that one of these lines originates from localized spins, the other from conduction electrons. The concentration of the “localized spins”, generally speaking, decreases with doping. The Pauli-like susceptibility associated with the conduction electrons changes from 1.5×10−7 to 15×10−7 emu·cm3/mole for various doping levels and correlates with the conductivity of the same samples. The longitudinal relaxation time of the localized spins in doped trans-rich was found to beT 1≅100 μs at low temperatures, consistent with values of others in undoped trans rich. The temperature dependence of the homogeneous transverse relaxationT 2 of the localized spins in doped trans-rich polyacetylene is similar to that of undoped trans polyacetylene. These facts show that the localized spins originate from undoped regions of the doped polyacetylene, perhaps due to inhomogenous doping. Our results are consistent with either formation of metallic islands, or, probably more, with impurity band conduction in strongly disordered semiconductors.
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Shirakawa, H., Louis, E.J., MacDiarmid, A.G., Chiang, C.K., Heeger, A.J.: J. Chem. Soc. Chem. Commun.1977, 578
Chiang, C.K., Druy, M.A., Gau, S.C., Heeger, A.J., Shirakawa, H., Louis, E.J., MacDiarmid, A.J., Park, Y.W.: J. Am. Chem. Soc.100, 1013 (1978)
Chiang, C.K., Fincher, C.R., Jr., Park, Y.W., Heeger, A.J., Shirakawa, H., Louis, E.J., Gau, S.C., MacDiarmid, A.G.: Phys. Rev. Lett.39, 1098 (1977)
Chiang, C.K., Park, Y.W., Heeger, A.J., Shirakawa, H., Louis, E.J., MacDiarmid, A.J.: J. Chem. Phys.69, 5098 (1978)
Ikehata, S., Kaufer, J., Woerner, T., Pron, A., Druy, M.A., Sivak, A., Heeger, A.J., MacDiarmid, A.G.: Phys. Rev. Lett.45, 1123 (1980)
Weinberger, B.R., Kaufer, J., Heeger, A.J., Pron, A., MacDiarmid, A.G.: Phys. Rev. B20, 223 (1979)
Su, W.P., Schrieffer, J.R., Heeger, A.J., Phys. Rev. Lett.42, 1698 (1979); Phys. Rev. B22, 2099 (1980)
Rice, M.J.: Phys. Lett.71A, 152 (1979)
Tomkiewicz, Y., Schultz, T.D., Brom, H.B., Clarke, T.C., Street, G.B.: Phys. Rev. Lett.43, 1532 (1979)
Tomkiewicz, Y., Schulz, T.D., Brom, H.B., Taranko, A.R.: Phys. Rev. B24, 4348 (1981)
Ito, T., Shirakawa, H., Ikeda, S.: J. Polym. Sco.12, 11 (1974)
Shirakawa, H., Ito, T., Ikeda, S.: Makromol. Chem.179, 1565 (1978)
Chang, T., Kahn, A.H.: NBS Special Publication 260-59, National Bureau of Standarts Certificate (standard reference material 2601), Washington D.C. 20234 (1978)
Dyson, F.J.: Phys. Rev.98, 349 (1954)
Fehr, G., Kip, A.F.: Phys. Rev.98, 337 (1954)
Chien, JC.W.: J. Polym. Sci. Polym. Lett. Ed.19, 249 (1981)
Devreux, F., Genoud, F., Gulielmi, M., Holezer, K., Nechtschein, M.: (to be published)
Actually most of our ESR lines were analyzed using a “Dysonian lineshape” of the form χ″(ω)+αχ(ω) where χ″ (ω) is the absorption part and χ″ (ω) is the dispersion part. However, α is very small (α≲0.1) for our very thin samples and the approximation of pure Lorenzian is valid
Castner, T.G., Jr.: Phys. Rev.115, 1506 (1959)
Poole, C.P.: Electron spin resonance. A comprehensive treatise on experimental technique. New York: Interscience 1967
Chien, J.C.W., Wnek, G.E., Karasz, F.F., Warakomski, J.M., Dickinson, L.C., Heeger, A.J., MacDiarmid, A.G.: Macromolecules15, 614 (1982)
Dalton, L.R., Thoman, H., Tomkiewicz, Y., Shiren, N.S., Clarke, T.C.: Symp. Cond. Polymer, Am. Chem. Soc., Las Vegas (1982)
Mehring, M., Weber, H., Müller, W., Wegner, G.: Solid State Commun. (in press)
Milo, O., Palchan, I., Davidov, D., Selig, H.: (submitted for publication)
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Davidov, D., Roth, S., Neumann, W. et al. ESR and conductivity studies of doped polyacetylene. Z. Physik B - Condensed Matter 51, 145–151 (1983). https://doi.org/10.1007/BF01308768
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DOI: https://doi.org/10.1007/BF01308768