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| 2. |
- Guo, J.-H., et al.
(författare)
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How the phenyle rings (benzene) act as building blocks in pi conjugated polymers
- 1998
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Ingår i: Advanced Light Source. - Berkeley : Ernest Orlando Lawrence Berkeley National Laboratory, University of California Berkeley, California, USA. ; , s. 129-132
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Organic conjugated polymers have the electronic structure of semiconductors and can be doped to become good conductors (1). Conjugated polymers are now used as active materials in a wide variety of prototype applications such as light emitting diodes [2] and organic transistors [3,4]. Most of the interesting chemistry and physics of conjugated polymers is associated with the details of the electronic structure at the valence and conduction band edges and, in this connection, various electron spectroscopies can be used as tools for diagnosis of the relevant electronic and geometric properties....
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| 3. |
- Guo, J.-H., et al.
(författare)
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Resonant and nonresonant x-ray scattering spectra of some poly(phenylenevinylene)s
- 1998
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 108:14, s. 5990-5996
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Tidskriftsartikel (refereegranskat)abstract
- The electronic structure of some poly(phenylenevinylene)s have been investigated by resonant and nonresonant x-ray inelastic scattering spectroscopies. The nonresonant as well as all resonant spectra for each polymer demonstrate benzene-like features, indicating a local character of the x-ray emission in which the phenyl ring acts as a building block. Theoretical simulations of x-ray energies and intensities taking the repeat unit as a model molecule of the polymer agree with the experimental spectra fairly well. The edges of the occupied bands have been identified in the nonresonant spectra of each polymer. By subtracting the emission energy of the highest occupied molecular orbital in the nonresonant spectrum from the core excitation energy in the resonant spectrum an alternative way to determine the optical band gap is obtained. As for free benzene the outer π band in the polymer spectra show a depletion of the emission going from the nonresonant to the resonant x-ray emission spectra. It is demonstrated that this transition, which is strictly symmetry forbidden for free benzene, becomes effectively forbidden in the polymer case as a result of strong interference effects, and it is argued that this is the general case for resonant x-ray emission of conjugated polymers as far as the frozen orbital approximation holds.
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| 4. |
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| 5. |
- Sjostrom, H, et al.
(författare)
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Growth of CNxHy films by reactive magnetron sputtering of carbon in Ar/NH3 discharges
- 1996
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Ingår i: JOURNAL OF MATERIALS RESEARCH. - : MATERIALS RESEARCH SOCIETY. ; 11:4, s. 981-988
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Results on hydrogenated carbon nitride (CNxHy) thin films grown by reactive magnetron sputtering in a mixed Ar/NH3 discharge are reported. Depending on the growth temperature (T-s) and negative substrate bias voltage (V-s), both the composition and the mi
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| 6. |
- Xing, K. Z., et al.
(författare)
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The electronic and geometric structures of neutral and potassium-doped poly[3-(4-octylphenyl)thiophene] studied by photoelectron spectroscopy
- 1996
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Ingår i: Synthetic metals. - : Elsevier. - 0379-6779 .- 1879-3290. ; 76:1-3, s. 263-267
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Tidskriftsartikel (refereegranskat)abstract
- The electronic and geometric structures of poly [3-(4-octylphenyl)thiophene] have been studied by X-ray and ultraviolet photoelectron spectroscopy (XPS and UPS, respectively). Thermochromic effects, and new charge induced states generated by potassium doping, have been observed by direct UPS measurements. The experimental results are in very good agreement with the results of theoretical quantum chemical calculations performed with the Austin Model 1 semi-empirical model and the valence-effective Hamiltonian pseudo-potential model.
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| 7. |
- Xing, K. Z., et al.
(författare)
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The electronic structure of neutral and alkali metal-doped poly[3-(4-octylphenyl)thiophene] studied by photoelectron spectroscopy
- 1996
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Ingår i: Synthetic metals. - : Elsevier. - 0379-6779 .- 1879-3290. ; 80:1, s. 59-66
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Tidskriftsartikel (refereegranskat)abstract
- The electronic structure of poly [3-(4-octylphenyl)thiophene] (POPT) has been studied by ultraviolet photoelectron spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS), as well as by quantum chemical calculations. Both temperature-dependent effects on the electronic structure of the neutral system, as well as the generation of new electronic states induced by doping with alkaline metals, have been observed. The experimental results are in good agreement with the results of the quantum chemical calculations.
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| 8. |
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