Semitransparent cathodes for organic light emitting devices

Burrows, P. E.; Gu, G.; Forrest, Stephen R.; Vicenzi, Edward P.; Zhou, Theodore X.

doi:10.1063/1.372303

Cited by 112 publications

(53 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…79,80 For example, sputtering ITO without specifically heating the substrate often leads to lower electrical conductivity and/or lower optical transparency than in commercially available ITO electrodes on glass substrates, which generally require high substrate temperatures during deposition or high temperature postdeposition annealing. 9 When using ITO as the top electrode, it is desirable to use some buffer layers or sacrificial layers, such as organic protective layers [e.g., copper phthalocyanine (CuPc) layer], 81 thin metal layers (e.g., Mg/Ag layer), 82 or some transition metal oxide layers (e.g., MoO x ), 83 to protect the underlying organic active layer during ITO deposition, without negatively affecting the charge injection/transport characteristics of the device. Low-energy magnetron sputtering methods have also been developed to reduce the damages to organic layers.…”

Section: Transparent Conductive Oxidesmentioning

confidence: 99%

Transparent electrodes for organic optoelectronic devices: a review

et al. 2014

View full text Add to dashboard Cite

Abstract. Transparent conductive electrodes are one of the essential components for organic optoelectronic devices, including photovoltaic cells and light-emitting diodes. Indium-tin oxide (ITO) is the most common transparent electrode in these devices due to its excellent optical and electrical properties. However, the manufacturing of ITO film requires precious raw materials and expensive processes, which limits their compatibility with mass production of large-area, low-cost devices. The optical/electrical properties of ITO are strongly dependent on the deposition processes and treatment conditions, whereas its brittleness and the potential damage to underlying films during deposition also present challenges for its use in flexible devices. Recently, several other transparent conductive materials, which have various degrees of success relative to commercial applications have been developed to address these issues. Starting from the basic properties of ITO and the effect of various ITO surface modification methods, here we review four different groups of materials, doped metal oxides, thin metals, conducting polymers, and nanomaterials (including carbon nanotubes, graphene, and metal nanowires), that have been reported as transparent electrodes in organic optoelectronic materials. Particular emphasis is given to their optical/electrical and other material properties, deposition techniques, and applications in organic optoelectronic devices.

show abstract

Section: Transparent Conductive Oxidesmentioning

confidence: 99%

Transparent electrodes for organic optoelectronic devices: a review

et al. 2014

View full text Add to dashboard Cite

show abstract

“…Even if the layer thickness of, e.g., a Mg-Ag alloy (an established cathode material for OLEDs) is reduced to 8 nm, a total transmittance of 50% cannot be exceeded. [6] However, transparent displays, e.g., automobile windshields, require a minimum total transmittance of 75% for safety reasons. In contrast, organic buffer layers can provide an adequate transmittance, e.g., copper phthalocyanine (CuPc) or pentacene.…”

mentioning

confidence: 99%

Transparent Inverted Organic Light‐Emitting Diodes with a Tungsten Oxide Buffer Layer

et al. 2008

View full text Add to dashboard Cite

Organic light-emitting diodes (OLEDs) have already proven their readiness for commercialization in terms of lifetime and efficiency.[1] Nevertheless, it will be a challenge forOLEDs to compete against liquid-crystal displays (LCDs) for standard applications. While the angle-of-view dependency and the low contrast of liquid-crystal and plasma displays are no longer forceful arguments for OLED displays, high power efficiencies still render OLEDs a desirable display technique. Moreover, OLEDs could enable novel display applications; considerable relevance is attributed to the achievable high transparency of organic devices. The constituting layers of an OLED can be tailored to absorb only in the ultraviolet. The emission zone may exhibit a large Stokes shift. Thus, entirely see-through displays that can be integrated, for instance in automobile windshields to assist the driver, or provide additional visual information for a surgeon during a biopsy, may be realized.[2]The setup of transparent OLEDs requires transparent electrodes on the bottom and the top sides of the device. Currently, indium tin oxide (ITO) is the established conducting material, due to its high transparency. A 100 nm thick layer of ITO has a transparency above 80% throughout the visible part of the spectrum, and provides sufficiently large conductivity for OLED applications, of 20 V sq À1

show abstract

“…Our results show that there should be a critical value of Al thickness existing (between 10 nm and 15 nm) for achieving a good electron injection as the luminance and η L increase slowly further after a sharp increment between 10nm and 15 nm. As we all known, a qualified intermediate electrode should not only provide excellent injection and connection, but also it must have good transmission to guarantee visible light to pass through easily [10,17]. Figure 3 shows the transmission spectra of Al/Au (10 nm) thin films in the visible range with the Al thickness being varied from 5 nm to 30 nm.…”

Section: Resultsmentioning

confidence: 99%

An effective intermediate Al/Au electrode for stacked color-tunable organic light emitting devices

Zheng

Choy

2008

SPIE Proceedings

View full text Add to dashboard Cite

Bright and efficient stacked color-tunable organic light emitting devices (OLEDs) using intermediate Al/Au electrode have been reported. The effects of the thickness of Al and Au layer on the luminance characteristics have been comprehensively studied. After the optimization, After the optimization, the bottom-emission single-unit OLED of 4,4',4''-Tris(N-3-methylphenyl-N-phenyl-amino) triphenylamine /N,N′-diphenyl-N,N′-bis(1-naphthyl)-(1,1′-biphenyl)-4,4′-diamine /tris(8-hydroxyquinoline) aluminum has a maximum luminance efficiency (η L ) of 3.37 by using Al/Au as the cathode and 2.92 cd/A by using Al/Au as the anode. By introducing the optimized intermediate Al/Au electrode into the stacked color-tunable OLEDs, red unit with maximum η L of 4.73 cd/A and blue unit with maximum η L of 3.96 cd/A have been obtained. The color can be tuned efficiently along a linear route from pure red with the Commission Internationale de l'Eclairage (CIE) coordinates of (0.662, 0.330) to sky blue with the CIE coordinates of (0.155, 0.340). This scheme can be a potential candidate for achieving high brightness and efficient stacked color-tunable OLEDs.

show abstract

Semitransparent cathodes for organic light emitting devices

Cited by 112 publications

References 27 publications

Transparent electrodes for organic optoelectronic devices: a review

Transparent electrodes for organic optoelectronic devices: a review

Transparent Inverted Organic Light‐Emitting Diodes with a Tungsten Oxide Buffer Layer

An effective intermediate Al/Au electrode for stacked color-tunable organic light emitting devices

Contact Info

Product

Resources

About