A study of the ITO-on-PPV interface using photoelectron spectroscopy

Johansson, Nils; Cacialli, Franco; Xing, Kezhao; Beamson, G.; Clark, D. T.; Friend, Richard H.; Salaneck, W. R.

doi:10.1016/s0379-6779(98)80088-x

Cited by 58 publications

(28 citation statements)

References 20 publications

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“…This represents a decrease in performance compared to [5] by 1 Mb/s. The reason for the unexpected decrease in performance can be attributed to the PRBS length; which was increased from 2 10 [5] to 2…”

Section: Resultsmentioning

confidence: 99%

“…The ITO surface was cleaned by sonication in acetone and isopropanol. An oxygen plasma treatment of the cleaned ITO substrates was done to increase the work function and to reduce the surface roughness [9,10]. A hole-injection layer (~40 nm) of PEDOT:PSS (Heraeus Clevios™ P VP AI 4083) was deposited via spincoating (5000 rpm for 30 s in air) on top of the ITO a few seconds after the oxygen plasma.…”

Section: Polymer Light Emitting Diode Processingmentioning

confidence: 99%

“…The received signal is sampled and digitized by a Tektronix MDO4104B-6 oscilloscope (1 GHz bandwidth). 10 7 samples per acquisition were recorded with a sampling frequency that was varied according to the data rate to give a maximum of 10 Sa/sym. The data is then loaded in MATLAB for further processing and down-sampled using an integrate and dump method.…”

Section: Fig 3 Schematic Block Diagram For the System Under Testmentioning

confidence: 99%

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A 20-Mb/s VLC Link With a Polymer LED and a Multilayer Perceptron Equalizer

Haigh

Bausi

Kanesan

et al. 2014

IEEE Photon. Technol. Lett.

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Section: Resultsmentioning

confidence: 99%

Section: Polymer Light Emitting Diode Processingmentioning

confidence: 99%

Section: Fig 3 Schematic Block Diagram For the System Under Testmentioning

confidence: 99%

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A 20-Mb/s VLC Link With a Polymer LED and a Multilayer Perceptron Equalizer

Haigh

Bausi

Kanesan

et al. 2014

IEEE Photon. Technol. Lett.

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“…Considerable amounts of effort have been devoted to the theoretical and experimental studies on the formation mechanisms of the interfaces between electroluminescent polymers and metals in recent years. 1,2 It has been found that cathodic metals, such as aluminium, calcium and magnesium, can react strongly with the organic or polymeric layer. 3,4 The use of an insulating layer (typically LiF or metal oxide) between the metal electrode and the emitting layer can dramatically improve the performance of the device.…”

Section: Introductionmentioning

confidence: 99%

In situ interfacial analysis of evaporated potassium on the electroluminescent fluorene–thiophene copolymer

Ling

Kang

et al. 2002

Surface & Interface Analysis

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X-ray photoelectron spectroscopy (XPS) was used to investigate the interface formation during in situ thermal evaporation of potassium on thin films of an electroluminescent conjugated polymer: poly[2,7-(9,9-dihexylfluorene)-co-alt-2,5-(decylthiophene)] (PFT). The chemical state and composition of the metal/polymer interfaces were studied as a function of the potassium coverage. Potassium was found to interact extensively with the bulk-adsorbed oxygen to form a layer of metal oxide at the K/PFT interface. Migration of the bulk-adsorbed oxygen to the surface occurred in response to the deposition of potassium onto the polymer. The changes in the S 2p lineshape suggested the formation of a thiolate species at low potassium coverages and also a sulphide species at higher metal coverages. The presence of charge transfer from the deposited potassium atoms to the carbon atoms of PFT suggested that the polymer had undergone n-type doping. The deposited potassium atoms also diffused into the subsurface region of the polymer film. Thus, the interface of K/PFT contained mainly the oxidized metal, metallic potassium and metal-polymer charge transfer complexes.

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“…Trichlorosilane-functionalized triarylamine II was synthesized (Scheme 1; see Experimental for details) by allylation [10,11] of tris(4-bromophenyl)amine to yield tris(4-allylphenyl)amine (I), which after chromatographic purification, was subjected to catalytic hydrosilylation. [12,13] HTL precursor II is a pale-yellow, air-sensitive oil which was purified by vacuum distillation, and was characterized by 1 H NMR, mass spectrometry, and elemental analysis.…”

mentioning

confidence: 99%

TiN as an Anode Material for Organic Light-Emitting Diodes

Adamovich

Shoustikov

Thompson³

1999

Adv. Mater.

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Organic light-emitting diodes (OLEDs) are currently receiving a great deal of attention, both academically and commercially. These devices have promise in applications ranging from low information content alphanumeric displays, to high resolution, large area flat panel displays. The most common OLED structure consists of a substrate coated with a transparent conductor (indium tin oxide, ITO) coated with a thin film of organic material(s), followed by a vapor deposited metal cathode. When a potential is applied to the device, holes are injected into the organic material(s) from the ITO electrode and electrons from the metal cathode. The holes and electrons recombine in the organic material, giving excitons, which radiatively relax to give off light. The efficiency of the device is best if multiple organic layers are used, i.e. separate hole and electron transporting layers.The choice of anode material for OLEDs is based on several criteria. The anode in a conventional OLED must have good optical transparency, good electrical conductivity and chemical stability, and a work function that lies near the HOMO levels of the organic materials to which it will inject holes. ITO fits these criteria and is the most widely used anode material in OLEDs. ITO films combine high transparency (» 90 %) with low resistivity (1´10 ±3 ±71 0 ±5 W cm). [1,2] Thin films of ITO can be prepared by a variety of methods, including sputtering, chemical vapor deposition (CVD) and sol-gel techniques.[2] The work function of ITO (4.4±4.7 eV based on ultraviolet photoemission spectroscopy measurements) [3±4] lies near the HOMO levels of typical OLED hole transporting or injecting material, which leads to a small barrier for hole injection into the organic material. It has been found that the ITO electrode can be treated to reduce this energy barrier. For example, devices with lower drive voltage and higher brightness have been prepared by treating the ITO surface with an oxygen plasma [5] or aqua regia. [6] The authors stressed the relationship between the surface morphology of the ITO and the device behavior. The device stability and efficiency strongly depend on the nature of the anode/organic interface. [7] One of the causes of long term OLED degradation involves the diffusion of metal ions or oxygen from the ITO into the organic film.[8±10]By introducing an ultra-thin interlayer of different organic materials at the interface, the efficiency of the devices could be improved.[11] Application of ITO covered with polyaniline film in the same type of devices also gives better results in terms of carrier injection and electroluminescence efficiency. [12,13] Polyaniline film serves as a barrier that prevents oxygen from diffusing out of the ITO and thus stabilizes the electrode±organic interface. In addition to polymers, copper phthalocyanine (CuPc) [3] and aluminum oxide [14] have been used as hole-injecting buffer layers between the ITO electrode and hole-transporting materials in OLEDs. Although the ITO electrode can be used efficiently with m...

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A study of the ITO-on-PPV interface using photoelectron spectroscopy

Cited by 58 publications

References 20 publications

A 20-Mb/s VLC Link With a Polymer LED and a Multilayer Perceptron Equalizer

A 20-Mb/s VLC Link With a Polymer LED and a Multilayer Perceptron Equalizer

In situ interfacial analysis of evaporated potassium on the electroluminescent fluorene–thiophene copolymer

TiN as an Anode Material for Organic Light-Emitting Diodes

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