Polymer band alignment at the interface with indium tin oxide: consequences for light emitting devices

Kugler, Thomas; Salaneck, W. R.; Rost, H.; Holmes, Andrew B.

doi:10.1016/s0009-2614(99)00824-6

Cited by 126 publications

(60 citation statements)

References 17 publications

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“…PEDOT:PSS. [41] The 2:10 doped films show such a substrate-independent behavior of org/sub (Fig. 2), in agreement with the classical semiconductor physics' model and the general highly-doped conducting polymer behavior, [42] but the other films clearly do not, so a different mechanism has to be invoked to explain the energy level alignment for the case of low to intermediate doping.…”

Section: Resultssupporting

confidence: 77%

Energetics at Doped Conjugated Polymer/Electrode Interfaces

Bao

Liu

Gao

et al. 2014

Adv Materials Inter

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Abstract:The energy level alignment at molecule-doped conjugated polymer/electrode interface is investigated. We find regular plots with a constant thickness-independent displacement away from the original energy level alignment behavior of the pristine polymer at low to intermediate level for molecule-doped conjugated polymer/conducting substrate interfaces.We proposed that two combined processes control the energy level alignment: (i) equilibration of the Fermi level due to oxidation (or reduction) of polymer sites at the interface as per the integer charge transfer model and (ii) a double dipole step induced by image charge from the dopant-polymer charge transfer complex that cause a shift of the work function. Such behavior is expected to hold for all low to intermediate level doped organic semiconductor systems.

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Section: Resultssupporting

confidence: 77%

Energetics at Doped Conjugated Polymer/Electrode Interfaces

Bao

Liu

Gao

et al. 2014

Adv Materials Inter

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“…4 is depicted the energy level diagram derived from the ICT model for the ITO/PEDOT-PSS/MDMO-PPV/PCBM/Al case (flat band condition). The ITO/PEDOT-PSS interface behaves as a metal/metal contact [36] with the resulting work function increasing from 4.7 eV to 5.2 eV with a 0.5 eV dipole shift of the vacuum level. Since the new work function is larger than the E ICT+ energy of MDMO-PPV, spontaneous charge transfer will occur from MDMO-PPV to PEDOT-PSS at the interface until equilibrium is reached.…”

Section: Resultsmentioning

confidence: 99%

Energy-Level Alignment at Metal–Organic and Organic–Organic Interfaces in Bulk-Heterojunction Solar Cells

Sehati

Lindell

Liu

et al. 2010

IEEE J. Select. Topics Quantum Electron.

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Abstract-Ultraviolet photoelectron spectroscopy measurements in combination with the Integer Charge Transfer model is used to obtain the energy level alignment diagrams for two common types of bulk heterojunction solar cell devices based on poly(3-hexylthiophene) or poly(2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene) as the donor polymer and (6,6)-phenyl-C61-butric-acid as the acceptor molecule. A ground state interface dipole at the donor/acceptor heterojunction is present for both systems but the origin of the interface dipole differs, quadrupole-induced in the case of poly(2-methoxy-5-(3',7'-dimethyl-octyloxy)-1,4-phenylene vinylene) and integer charge transfer state based for poly(3-hexylthiophene). The presence of bound electron-hole charge carriers (charge transfer states) and/or interface dipoles is expected to enhance exciton dissociation into free charge carriers, reducing the probability that the charges become trapped by Coulomb forces at the interface followed by recombination.

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“…This is the common argument typically followed in the literature 16,22,24 and also typically assumed for contact properties, where ITO is usually treated like a metal. 11,15,52 In (b) there is a high density of surface states in the fundamental band gap and the Fermi energy crosses the surface band. Such a situation is, e.g., present at the Si(111)7x7 surface.…”

Section: Discussionmentioning

confidence: 99%

Surface states, surface potentials, and segregation at surfaces of tin-dopedIn2O3

et al. 2006

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Surfaces of In 2 O 3 and tin-doped In 2 O 3 (ITO) were investigated using photoelectron spectroscopy. Parts of the measurements were carried out directly after thin film preparation by magnetron sputtering without breaking vacuum. In addition samples were measured during exposure to oxidizing and reducing gases at pressures of up to 100 Pa using synchrotron radiation from the BESSY II storage ring. Reproducible changes of binding energies with temperature and atmosphere are observed, which are attributed to changes of the surface Fermi level position. We present evidence that the Fermi edge emission observed at ITO surfaces is due to metallic surface states rather than to filled conduction band states. The observed variation of the Fermi level position at the ITO surface with experimental conditions is accompanied by a large apparent variation of the core level to valence band maximum binding energy difference as a result of core-hole screening by the free carriers in the surface states. In addition segregation of Sn to the surface is driven by the surface potential gradient. At elevated temperatures the surface Sn concentration reproducibly changes with exposure to different environments and shows a correlation with the Fermi level position.

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Polymer band alignment at the interface with indium tin oxide: consequences for light emitting devices

Cited by 126 publications

References 17 publications

Energetics at Doped Conjugated Polymer/Electrode Interfaces

Energetics at Doped Conjugated Polymer/Electrode Interfaces

Energy-Level Alignment at Metal–Organic and Organic–Organic Interfaces in Bulk-Heterojunction Solar Cells

Surface states, surface potentials, and segregation at surfaces of tin-dopedIn2O3

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