Improved efficiency in polymer light-emitting diodes using air-stable electrodes

Aratani, Sukekazu; Zhang, C.; Pakbaz, K.; Höger, Sigurd; Wudl, Fred; Heeger, Alan J.

doi:10.1007/bf02817349

Cited by 59 publications

(20 citation statements)

References 10 publications

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“…The addition of side fects, areas of the LED that become nonemissive and increase the overall impedance of the device. junction with charge-transporting layers 6 and and the polymer/metal interface. This is a singlethrough the development of electrochemical cells 7 reflection technique in which the incident IR that operate under lower applied voltages, use beam strikes the sample at a grazing angle of less reactive metal electrodes, and do not exhibit about 10Њ from the surface.…”

Section: Introductionmentioning

confidence: 99%

Photooxidative stability of substituted poly(phenylene vinylene) (PPV) and poly(phenylene acetylene) (PPA)

Cumpston

Jensen

1998

J. Appl. Polym. Sci.

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The addition of side groups to improve the photooxidative stability of polymers used in polymer-based light-emitting diodes (LEDs) is explored. Infrared spectroscopy and computational chemistry techniques are used to study the effects of chemical substitution of the reactive vinylene moiety in poly(phenylene vinylene) (PPV). The bond order of the vinylene group in small oligomers is calculated using semiempirical techniques to assess the improvement in stability toward oxidants such as singlet oxygen. We find that PPV dimers allow relative comparisons across a range of possible substitutions. Experimental results correlate well with these calculations. The addition of electron-withdrawing substituents, such as nitrile groups, to the vinylene moiety is found to be particularly effective in reducing the reactivity of alkoxy-substituted PPV toward singlet oxygen. The photooxidative stability of a poly(phenylene acetylene) (PPA) derivative is also studied. It appears that this family of polymers is more stable toward photooxidation than are its PPV analogs.

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Section: Introductionmentioning

confidence: 99%

Photooxidative stability of substituted poly(phenylene vinylene) (PPV) and poly(phenylene acetylene) (PPA)

Cumpston

Jensen

1998

J. Appl. Polym. Sci.

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“…It is necessary to use a low work function metal such as calcium ͑Ca͒ to reduce electron injection barrier for a higher efficiency. 2,6 Such metals, however, are so susceptible to moisture and oxygen that the resulting devices suffer from poor environmental stability. Various methods have been tried to achieve balanced injection of holes and electrons without using low work function metals.…”

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confidence: 99%

Effect of polymer-insulating nanolayers on electron injection in polymer light-emitting diodes

Park

et al. 2004

Applied Physics Letters

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We report the effect of polymer-insulating nanolayers on electron injection in the polymer light-emitting diodes (PLEDs) in which a hole is the major charge carrier. Several different polymer nanolayers with varying dielectric constants were placed between the emitting layer and the aluminum cathode, and their influence on the device performance was investigated. The device with a nanolayer of lower dielectric constant demonstrated higher luminescence quantum efficiency. In particular, when a ∼10-nm-thick polystyrene layer was employed, the device gave approximately two orders of magnitude higher external quantum efficiency than that of the one without an insulating nanolayer.

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“…Polymer blends of luminescent polymers and matrix polymers with good hole transporting property such as poly(9-vinylcarbozole), poly(methyl methacrylate) showed the enhancement of quantum efficiency [7][8][9][10][11]. The emission peak intensity of the luminescent polymer increased with increasing the composition ratio of the matrix polymer up to a certain ratio and then decreased [7].…”

Section: Introductionmentioning

confidence: 95%

“…Blending of luminescent polymers is an another useful method for color tuning and improvement of quantum efficiency. The efficient confinement of the singlet exciton which is responsible for the EL in polymer blend is expected to improve the quantum efficiency [7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

ElectroluminesCence Behavior in Polymer Blend of Two Luminescent Polymers

et al. 1995

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We report the electroluminescence behaviour of the devices made with the polymer blend of two emissible polymers, poly(2-methoxy,5-(2'-ethyl-hexoxy)-1,4-phenylene vinylene)(MEH-PPV) and poly[ 1,3-propanedioxy-1,4-phenylene-1,2-ethenylene-(2,5-bis(trimethylsilyl)-1,4-phenylene)-l,2-ethenylene-l,4-phenylene](B-polymer) luminescing at 580 nm and 480 nm respectively. The quantum efficiency increases with the composition ratio of B-polymer by two order of magnitude of that of MEH-PPV. Luminescence behaviour of the blend system was explained by hole blocking, exciton transfer behavior of the matrix polymer (B-polymer) and efficient confinement of the injected carriers in MEH-PPV.

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Improved efficiency in polymer light-emitting diodes using air-stable electrodes

Cited by 59 publications

References 10 publications

Photooxidative stability of substituted poly(phenylene vinylene) (PPV) and poly(phenylene acetylene) (PPA)

Photooxidative stability of substituted poly(phenylene vinylene) (PPV) and poly(phenylene acetylene) (PPA)

Effect of polymer-insulating nanolayers on electron injection in polymer light-emitting diodes

ElectroluminesCence Behavior in Polymer Blend of Two Luminescent Polymers

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