Space-charge limited current and electroluminescence in conjugated polymer-based LEDs

Savvateev, Vadim; Tarabia, M.; Chayet, H.; Farragi, E. Z.; Cohen, Gil; Kirstein, Stefan; Davidov, D.; Avny, Yair; Neumann, Ronny

doi:10.1016/s0379-6779(97)80235-4

Cited by 22 publications

(6 citation statements)

References 10 publications

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“…It was found that the copolymer with the longer conjugated rigid segments, the green-emitting copolymer, possesses a larger effective hole mobility, which was explained as the result of the lower average tunnelling distance when the conjugated segment is longer in these conjugated-non-conjugated copolymers (the spacer segment is the same in both polymers). The effective mobility values of the charge carriers reported for these copolymers are comparable to those reported for nominally homopolymers such as PPV [7][8][9][10][11]. The characteristic energy of the electron trap distribution was found to be 0.05 eV and 0.06 eV in the green-emitting and in the blue-emitting copolymers, respectively [6].…”

Section: Introductionsupporting

confidence: 72%

Electron and hole transport in a green-emitting alternating block copolymer: space-charge-limited conduction with traps

Hümmelgen

et al. 1999

J. Phys. D: Appl. Phys.

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The transport characteristics of electrons and holes in an alternating block copolymer, poly(1,8-octanedioxy-2,6-dimethoxy-1,4-phenylene-1,2-ethenylene-1,4phenylene-1,2-ethenylene-1,4-phenylene-1,2-ethenylene-3,5-dimethoxy-1,4-phenylene), have been investigated by current-voltage measurements in metal/polymer/metal sandwich structures. Strong evidence that the hole current is space-charge limited with a single discrete set of shallow traps and the electron current is space-charge limited with an exponential distribution of traps was obtained. A hole trap density of ∼1 × 10 17 cm −3 and a hole trap energy of ∼0.1 eV relative to the highest occupied molecular orbital level were determined. The characteristic energy of the trap distribution, ∼0.05 eV, and the trap density <3.7 × 10 17 cm −3 for electrons were also estimated. It was found that the hole current became trap-free, space-charge limited, when using Au, Pd or Ni (φ Au ≈ φ P d ≈ φ Ni ≈ 5.1 eV) instead of Cu as the anode, indicating that the hole trap energy must lie between φ Cu (≈4.65 eV) and φ Au . A hole mobility of ∼10 −6 cm 2 V −1 s −1 in this copolymer was determined.

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Section: Introductionsupporting

confidence: 72%

Electron and hole transport in a green-emitting alternating block copolymer: space-charge-limited conduction with traps

Hümmelgen

et al. 1999

J. Phys. D: Appl. Phys.

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“…Mobility measurements were done using the following diode structures: ITO/PEDOT:PSS/active material/Au for holes and Al/active material/Al for electrons. The charge carrier mobilities were calculated using the space-charge limited current (SCLC) model . Au (1000 Å) and Al (500 Å) electrodes were thermally evaporated at a pressure of 1 × 10 −7 Torr at room temperature using a shadow mask (Angstrom Engineering, Inc.).…”

Section: Methodsmentioning

confidence: 99%

A Low Band Gap, Solution Processable Oligothiophene with a Diketopyrrolopyrrole Core for Use in Organic Solar Cells

Tamayo¹,

Walker²,

Nguyen³

2008

J. Phys. Chem. C

358

296

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We synthesized a low band gap, solution processable oligothiophene derivative functionalized with a diketopyrrolopyrrole core, which is a highly absorbing chromophoric group. This design leads to optical absorption that extends to 720 nm in solution and to 820 nm in the film. Cyclic voltammetry shows quasireversible oxidation and reduction processes. Bulk heterojunction solar cells using [6,6]-phenyl C61-butyric acid methyl ester (PCBM) as the electron acceptor were fabricated. The power conversion efficiencies (PCEs) depend on the donor-acceptor ratio. A 70:30 donor/acceptor by weight mixture provided a PCE of 2.3% under simulated AM 1.5 solar irradiation of 100 mW/cm 2 . To date, this is the highest efficiency reported for small molecule-based solution processed bulk heterojunction solar cells.

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“…In order to investigate the carrier mobility of this luminescent metallomesogen, here, we measured its hole mobility by the SCLC method using a device structure of ITO/PEDOT (50 nm)/(biC 12 ppy-fl)-Pt 2 (C 12 DBM) 2 (50 nm)/MoO 3 (10 nm)/Al (90 nm). For the hole-only devices, SCLC is described by the formula J = (9/ 8)ε 0 ε r μ(V/d 3 ), 24 where J is the current density, ε 0 is the permittivity under vacuum (ε 0 = 8.85 × 10 −12 F/m), ε r is the dielectric constant (ε r = 3), μ is the hole mobility, and d is the sample thickness. As a result, the current−voltage (IV) characteristics taken under pulsed conditions are shown in Figure 6.…”

Section: ■ Introductionmentioning

confidence: 99%

Highly Dichroic Metallomesogen of Dinuclear Platinum Complex: Synthesis and Liquid Crystal and Photophysical Properties

Wang

Chen

et al. 2012

J. Phys. Chem. C

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A novel dinuclear platinum complex of (biC 12 ppy-fl)-Pt 2 C 12 DBM) 2 with liquid crystal luminescent property has been prepared, as well as its liquid crystal, optophysical properties and hole mobility have been studied, where biC 12 ppy-fl is 6,6′-[4,4′-(9,9-didodecyl-9H-fluorene-2,7-diyl)bis-(1,4-phenylene)]bis [3-(dodecyloxymethyl)pyridine] and C 12 DBM is 1,3-bis[4-(dodecyloxy)phenyl]propane-1,3-dione. This dinuclear platinum complex displayed a smectic mesophase and excellent opto-physical properties. Compared to the reported mononuclear platinum complex of (C n ROppy)Pt-(acac) (R = H, F), this dinuclear platinum complex exhibited higher emission quantum yield and higher stability, as well as higher hole mobility of 8.4 × 10 −4 cm 2 /(V s). Moreover, a highly polarized ratio of 10.3 was obtained for the aligned film of (biC 12 ppy-fl)Pt 2 (C 12 DBM) 2 on the aligned polyimide at room temperature.

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Space-charge limited current and electroluminescence in conjugated polymer-based LEDs

Cited by 22 publications

References 10 publications

Electron and hole transport in a green-emitting alternating block copolymer: space-charge-limited conduction with traps

Electron and hole transport in a green-emitting alternating block copolymer: space-charge-limited conduction with traps

A Low Band Gap, Solution Processable Oligothiophene with a Diketopyrrolopyrrole Core for Use in Organic Solar Cells

Highly Dichroic Metallomesogen of Dinuclear Platinum Complex: Synthesis and Liquid Crystal and Photophysical Properties

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