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WO2005096401A2 - Structure de dispositif destinee a ameliorer la fiabilite d'une diode electroluminescente organique (oled) - Google Patents

Structure de dispositif destinee a ameliorer la fiabilite d'une diode electroluminescente organique (oled) Download PDF

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Publication number
WO2005096401A2
WO2005096401A2 PCT/EP2005/003331 EP2005003331W WO2005096401A2 WO 2005096401 A2 WO2005096401 A2 WO 2005096401A2 EP 2005003331 W EP2005003331 W EP 2005003331W WO 2005096401 A2 WO2005096401 A2 WO 2005096401A2
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WIPO (PCT)
Prior art keywords
layer
light emitting
thickness
interlayer
hole transporting
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PCT/EP2005/003331
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WO2005096401A3 (fr
Inventor
Pierre-Marc Allemand
Vi-En Choong
Brian H. Cumpston
Rahul Gupta
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Ams Osram International GmbH
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Osram Opto Semiconductors GmbH
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Priority claimed from US10/895,862 external-priority patent/US20060017057A1/en
Application filed by Osram Opto Semiconductors GmbH filed Critical Osram Opto Semiconductors GmbH
Publication of WO2005096401A2 publication Critical patent/WO2005096401A2/fr
Publication of WO2005096401A3 publication Critical patent/WO2005096401A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/11—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/18—Carrier blocking layers
    • H10K50/181—Electron blocking layers
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K2102/00—Constructional details relating to the organic devices covered by this subclass
    • H10K2102/301—Details of OLEDs
    • H10K2102/351—Thickness
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/14—Carrier transporting layers
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
    • H10K85/10—Organic polymers or oligomers
    • H10K85/111—Organic polymers or oligomers comprising aromatic, heteroaromatic, or aryl chains, e.g. polyaniline, polyphenylene or polyphenylene vinylene
    • H10K85/113—Heteroaromatic compounds comprising sulfur or selene, e.g. polythiophene
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
    • H10K85/10—Organic polymers or oligomers
    • H10K85/111—Organic polymers or oligomers comprising aromatic, heteroaromatic, or aryl chains, e.g. polyaniline, polyphenylene or polyphenylene vinylene
    • H10K85/113—Heteroaromatic compounds comprising sulfur or selene, e.g. polythiophene
    • H10K85/1135—Polyethylene dioxythiophene [PEDOT]; Derivatives thereof
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
    • H10K85/10—Organic polymers or oligomers
    • H10K85/111—Organic polymers or oligomers comprising aromatic, heteroaromatic, or aryl chains, e.g. polyaniline, polyphenylene or polyphenylene vinylene
    • H10K85/114—Poly-phenylenevinylene; Derivatives thereof
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
    • H10K85/10—Organic polymers or oligomers
    • H10K85/111—Organic polymers or oligomers comprising aromatic, heteroaromatic, or aryl chains, e.g. polyaniline, polyphenylene or polyphenylene vinylene
    • H10K85/115—Polyfluorene; Derivatives thereof

Definitions

  • An organic light emitting diode (“OLED”) display is typically comprised of: (1) a transparent anode (e.g. ITO (Indium Tin Oxide) on a substrate; (2) a hole transporting layer (“HTL”); (3) an electron transporting and light emitting layer (“emissive layer” or “LEP layer” (light emitting polymer layer)); and (4) a cathode.
  • a transparent anode e.g. ITO (Indium Tin Oxide) on a substrate
  • HTL hole transporting layer
  • emissive layer electron transporting and light emitting layer
  • the emissive layer in an OLED typically is composed of one or more organic compounds (such as monomers or polymers) dissolved in a solvent.
  • the organic solution may contain other elements such as wetting agents, cross-linking agents, side- groups and so on.
  • the emissive layer is fabricated by depositing this organic solution onto the HTL or other underlying layer and allowing or causing (by baking or cross- linking) the solution to dry into a film.
  • the organic solution may be deposited using selective deposition techniques such as inkjet printing or non-selective deposition techniques such as spin-coating.
  • the injection of charge earners into conjugated polymers is usually optimized by the matching of the work function of the electrode to the energy level into which the charges are to be injected. This limits the choice of electrodes that can be used with a given polymer, especially for the anode where the choice of electrodes are more limited. Because of the large barrier to hole injection from ITO, a typical transparent anode, a hole injection and transport layer (the HTL) is typically used to bridge the barrier and enhance injection. However, work in the literature has indicated that the reliability of the OLED device may be adversely affected by the use of these hole transport layers. This may be caused by the leaching out of constituents from the hole transport layer into the LEP that degrades the performance of the device during operation.
  • the device with an interlayer is marked by triangular-shaped markers and the device without the interlayer is marked by X-shaped markers.
  • This approach improves device reliability, but at a cost of higher operating voltages and a more complicated fabrication process.
  • Another method is to increase the thickness of the LEP, which effectively tilts the hole/electron ratio in favor of holes. This has also been shown to increase lifetime as discussed in the parent patent application and shown in FIG. 1. As shown in FIG. 1 , devices with a thicker LEP layer (A>B>C) show improved performance over a longer lifetime but also suffer from operating voltages (A>B>C). This approach bears the cost of higher operating voltages and that the change in operating voltage as a function of time is also very high.
  • the lifetime increase is predominantly due to the reduction of the initial luminance decay, while the main decay slope remains the same.
  • the magnitude of this reduction scales with the thickness of the LEP.
  • the luminance decay curve does not level off. This limits the amount of improvement that can be achieved with this method as there is a limit to where the increase of LEP thickness becomes impractical. Therefore, there is a need to improve OLED device efficiency and lifetime without these tradeoffs while still improving device reliability.
  • an organic light emitting diode (“OLED”) device with a plurality of stacked layers, comprises: a hole transporting layer; a light emitting polymer layer having a thickness, as measured between two layers adjacent thereto of more than eighty nanometers; and an interlayer disposed between said hole transporting layer and said light emitting polymer layer, said interlayer functioning to provide at least one of: a) aiding the injection of holes into said light emitting polymer layer; b) blocking of electrons from migrating to said hole transporting layer; and c) reducing of exciton quenching.
  • the light emitting polymer layer has a thickness, as measured between two layers adjacent thereto of between eighty and two hundred nanometers.
  • the OLED-device comprises an anode layer adjacent to the light emitting polymer layer and a cathode layer.
  • the hole transporting layer and the light emitting layer are formed using at least one organic material.
  • the light emitting polymer layer is formed using at least one of a selective deposition technique and a non-selective deposition technique.
  • a selective deposition technique inkjet printing and as non-selective deposition technique spin coating can be used.
  • the OLED-device can be used to create an OLED-display, such as a passive matrix display or an active matrix display.
  • the combined thickness of the light emitting polymer layer and the hole transporting layer is held fixed and the thickness of the hole transporting layer decreases with an increase in the thickness of the light emitting polymer layer.
  • the hole transporting layer has a thickness of about 30 nanometers.
  • the interlayer is formed using at least one of: poly(2,7-(9,9-di-n-octylfluorene)-(l,4-phenylene-((4-secbutylphenyl)imino)-i,4- phenylene), non-emitting forms of poly(p-phenylenevinylene), triarylamine type material and thiopene.
  • the interlayer has a thickness from about 5 nanometers to about 100 nanometers, preferably from about 10 nanometers to about 30 nanometers.
  • FIG. 1 illustrates device luminance and voltage at various LEP layer thickness for a set of OLED devices.
  • FIG. 2 illustrates device luminance and voltage at various for a set of OLED devices with and without an interlayer.
  • FIG. 3 illustrates device luminance and voltage for a set of OLED devices which combine thick LEP layers with interlayers.
  • FIG. 4 shows a cross-sectional view of an embodiment of an organic electronic device 405 according to at least one embodiment of the invention.
  • FIG. 5 illustrates the effects of thinner HTL layers in accordance with at least one embodiment of the invention.
  • an OLED device structure which combines the use of a "thick" light emitting polymer (LEP) layer and an interlayer between the LEP layer and HTL layer.
  • LEP light emitting polymer
  • An increase in LEP thickness and added interlayer is typically associated with a great increase in required drive voltage. This might be expected to decrease efficiency and lifetime because of the additional stress on the device. Higher operating voltages also imposes greater requirements on drivers needed to power the OLEDs, and increases power consumption of the OLEDs, reducing its attactiveness for use in portable devices.
  • the thick LEP layer combined with an interlayer actually and unexpectedly increases efficiency and lifetime.
  • an interlayer between the HTL and LEP layer may add to the total device thickness, thereby presumably increasing operating voltages and decreasing device lifetime, but this has experimentally been shown to be false.
  • a typical conventional OLED device with only an HTL and LEP layers may show an HTL of about 60 nm and LEP of 75 nm thickness.
  • an interlayer would be added and the LEP layer would be made thicker.
  • An example of such a device structure would include an HTL of 60 nm followed by an interlayer of 30 nm and an LEP layer of 125 nm thickness.
  • the initial operating voltage of such a device is even lower than a device with similar LEP thickness and no interlayer.
  • the luminance decay curve retains the leveling off behavior commonly associated with devices having an interlayer, which are necessary to have large improvements in device reliability.
  • This structure also retains the reduction of the initial luminance decay observed for thicker LEP devices.
  • the structure retains the low dV/dt (change in device operating voltage as a function of time) commonly associated with devices having an interlayer.
  • FIG. 3 illustrates the effects of utilizing a thick LEP layer in conjunction with an interlayer in an OLED device in accordance with at least one embodiment of the invention.
  • the first curve marked by X-shaped markers is of an OLED device which has a thick LEP layer but no interlayer (D).
  • the second curve marked by circle markers is of an OLED device which has an interlayer but no thick LEP layer (E).
  • the third curve, marked by triangular markers, is of an OLED device which, in accordance with at least one embodiment of the invention, has both a thick LEP layer and interlayer (F).
  • Device F shows the best improvement in lifetime retaining more of initial luminance as lifetime increases.
  • Device D with only a thick LEP layer has the advantage of less of an initial drop in luminance but a rapid rate of declining luminance at longer lifetimes.
  • the voltage required to drive device F is less than the voltage required to drive device D, even though the thickness of the organic layers in device F is greater (due to the presence of the interlayer).
  • the LEP drops a lot more voltage than the HTL.
  • increasing the LEP thickness by 30 nm, and reducing the HTL thickness by 30 nm might provide the same overall device thickness, but the operating voltage of that device may be higher.
  • Device E requires the lowest operating voltage but also has the greatest drop in initial luminance amongst the three devices. However, as shown in Fig. 2, the operating voltage of Device E is higher than that of a corresponding bi-laycr device with the same LEP thickness as expected. Even with the higher operating voltages, the lifetime of Device E is higher.
  • the OLED device 405 may represent one OLED pixel or sub-pixel of a larger OLED display.
  • the OLED device 405 includes a first electrode 41 1 on a substrate 408.
  • the term "on” includes when layers are in physical contact or when layers are separated by one or more intervening layers.
  • the first electrode 411 may be patterned for pixilated applications or unpatterned for backlight applications.
  • One or more organic materials is deposited into the aperture to form one or more organic layers of an organic stack 416.
  • the organic stack 416 is on the first electrode 411.
  • the organic stack 416 includes a hole transporting (conducting polymer) layer ("HTL") 417 and light emitting polymer (LEP) layer 420 and an interlayer 418 disposed between the HTL 417 and the LEP layer 420. If the first electrode 41 1 is an anode, then the HTL 417 is on the first electrode 411. Alternatively, if the first electrode 41 1 is a cathode, then the active electronic layer 420 is on the first electrode 411, and the HTL 417 is on the LEP layer 420.
  • the OLED device 405 also includes a second electrode 423 on the organic stack 416. Other layers than that shown in FIG. 4 may also be added including barrier, charge transport, and interface layers between or among any of the existing layers as desired.
  • the “thickness" of a given layer is the distance or extension of that layer in a vertical direction of the shown cross-section as measured between the bottom of the layer immediately above the given layer and the top of the layer immediately below the given layer.
  • Substrate 408 can be any material that can support the organic and metallic layers on it.
  • the substrate 408 can be transparent or opaque (e.g., the opaque substrate is used in lop-emitting devices). By modifying or filtering the wavelength of light which can pass through the substrate 408, the color of light emitted by the device can be changed.
  • the substrate 408 can be comprised of glass, quartz, silicon, plastic, or stainless steel; preferably, the substrate 408 is comprised of thin, flexible glass.
  • the preferred thickness of the substrate 408 depends on the material used and on the application of the device.
  • the substrate 408 can be in the form of a sheet or continuous film.
  • the continuous film can be used, for example, for roll-to-roll manufacturing processes which are particularly suited for plastic, metal, and metallized plastic foils.
  • the substrate can also have transistors or other switching elements built in to control the operation of an active-matrix OLED device.
  • a single substrate 408 is typically used to construct a larger OLED display containing many pixels (OLED devices) such as OLED device 405 arranged in some pattern.
  • the first electrode 41 1 functions as an anode (the anode is a conductive layer which serves as a hole-injecting layer and which comprises a material with work function greater than about 4.5 eN).
  • Typical anode materials include metals (such as platinum, gold, palladium, indium, and the like); metal oxides (such as lead oxide, tin oxide, ITO (Indium Tin Oxide), and the like); graphite; doped inorganic semiconductors (such as silicon, germanium, gallium arsenide, and the like); and doped conducting polymers (such as polyaniline, polypyrrole, polythiophene, and the like).
  • the first electrode 411 can be transparent, semi-transparent, or opaque to the wavelength of light generated within the device.
  • the thickness of the first electrode 411 can be from about lOnm to about lOOOnm, preferably, from about 50nm to about 200nm, and more preferably, is about lOOnm.
  • the first electrode layer 411 can typically be fabricated using any of the techniques known in the art for deposition of thin films, including, for example, vacuum evaporation, sputtering, electron beam deposition, or chemical vapor deposition.
  • the first electrode layer 41 1 functions as a cathode (the cathode is a conductive layer which serves as an electron-injecting layer and which comprises a material with a low work function).
  • the cathode rather than the anode, is deposited on the substrate 408 in the case of, for example, a top-emitting OLED.
  • Typical cathode materials are listed below in the section for the "second electrode 423".
  • the first electrode 411 was an anode comprised of ITO.
  • HTL 417 The HTL 417 has a much higher hole mobility than electron mobility and is used to effectively transport holes from the first electrode 41 1 to the substantially uniform organic polymer layer 420.
  • the HTL 417 is made of polymers or small molecule materials.
  • the HTL 417 can be made of tertiary amine or carbazole derivatives both in their small molecule or their polymer form, conducting polyaniline (“PANI”), or PEDOT:PSS (a solution of polyethylenedioxythiophene (“PEDOT”) and polystyrenesulfonic acid (“PSS”) available as Baytron P from HC Starck).
  • the HTL 417 can have a thickness from about 5nm to about 1000 nm, and is conventionally used from about 50 to about 250 nm. In one or more embodiments of the invention, a thin HTL is also disclosed.
  • a "thin" HTL would have a thickness of around 30 nm and can be combined with a thick LEP layer 420 and interlayer 418.
  • the HTL 417 can be formed using selective deposition techniques or nonselective deposition techniques.
  • selective deposition techniques include, for example, Inkjet printing, flex printing, and screen printing.
  • nonselective deposition techniques include, for example, spin coating, dip coating, web coating, and spray coating.
  • the hole transporting material is deposited on the first electrode 411 and then allowed to dry into a film.
  • the dried material represents the hole transport layer.
  • Interlayer 418 In accordance with at least one embodiment of the invention, a thick LEP layer is utilized in a device structure also having an interlayer between the LEP layer and the HTL layer.
  • an interlayer 418 is provided between HTL 417 and LEP layer 420.
  • the functions of the interlayer 418 are among the following: to help injection of holes into the LEP layer 420, reduce exciton quenching at the anode, possess better hole transport than electron transport, and block electrons from getting into the HTL 417 and degrading it.
  • Some materials may have one or two of the desired properties listed, but the effectiveness of the material as an interlayer is believed to improve with the number of these properties exhibited. Through careful selection of the materials, an efficient interlayer material can be found.
  • a criteria that can be used to find materials that can help injection of holes into the LEP layer 420 is that the HOMO (Highest Occupied Molecular Orbital) levels of the material bridge the energy banner between the anode and the LEP layer 420, that is the HOMO level of the interlayer 418 should be in between the HOMO levels of the anode and the LEP layer 420.
  • Charge earner mobilities of the materials can be used as a criteria to distinguish materials that will have better hole transport than electron transport.
  • materials that have higher LUMO (Lowest Unoccupied Molecular Orbital) levels than the LUMO of the LEP layer 420 will present a barrier to electron injection from the LEP layer 420 into the interlayer 418, and thus act as an electron blocker.
  • LUMO Large Unoccupied Molecular Orbital
  • the interlayer 418 may consist at least partially of or may derive from one or more following compounds, their derivatives, moieties, etc: poly(2,7-(9,9-di-n- octylfluorene)-(l,4-phenylene-((4-secbutylphenyl)imino)-l,4-phenylene) and derivatives which include cross-linkable forms, non-emitting forms of poly(p- phenylenevinylene), triurylamine type material, thiopene, etc.
  • the interlayer can have a thickness of anywhere between about 5 nm and 100 nm and preferably, has a thickness from about 10 nm to 30 m.
  • LEP Layer 420 For organic LEDs (OLEDs), the LEP layer 420 contains at least one organic material that emits light. These organic light emitting materials generally fall into two categories.
  • the first category of OLEDs referred to as polymeric light emitting diodes, or PLEDs, utilize polymers as part of LEP layer 420.
  • the polymers may be organic or organo-metallic in nature.
  • the term organic also includes organo-metallic materials.
  • these polymers are solvated in an organic solvent, such as toluene or xylene, and spun (spin-coated) onto the device, although other deposition methods are possible.
  • Devices utilizing polymeric active electronic materials in LEP layer 420 arc especially preferred.
  • LEP layer 420 may include a light responsive material that changes its electrical properties in response to the abso ⁇ tion of light.
  • Light responsive materials are often used in detectors and solar panels that convert light energy to electrical energy.
  • the light emitting organic polymers in the LEP layer 420 can be, for example, EL polymers having a conjugated repeating unit, in particular EL polymers in which neighboring repeating units are bonded in a conjugated manner, such as polythiophenes, polyphenylenes, polythiophenevinylenes, or poly-p- phenylenevinylenes or their families, copolymers, derivatives, or mixtures thereof.
  • the organic polymers can be, for example: polyfluorenes; poly-p- phenylenevinylenes that emit white, red, blue, yellow, or green light and are 2-, or 2, 5- substituted poly-p-pheneylenevinylenes; polyspiro polymers.
  • Preferred organic emissive polymers include LUMATION Light Emitting Polymers ("LEPs") that emit green, red, blue, or white light or their families, copolymers, derivatives, or mixtures thereof; the LUMATION LEPs are available from The Dow Chemical Company, Midland, Michigan.
  • Other polymers include polyspirofluorene-like polymers available from Covion Organic Semiconductors GmbH, Frankfurt, Germany.
  • LEP layer 420 In addition to polymers, smaller organic molecules that emit by fluorescence or by phosphorescence can serve as a light emitting material residing in LEP layer 420. Unlike polymeric materials that are applied as solutions or suspensions, small- molecule light emitting materials are preferably deposited through evaporative, sublimation, or organic vapor phase deposition methods. Combinations of PLED materials and smaller .organic molecules can also serve as active electronic layer. For example, a PLED may be chemically derivatized with a small organic molecule or simply mixed with a small organic molecule to form LEP layer 420. In addition to active electronic materials that emit light, LEP layer 420 can include a material capable of charge transport. Charge transport materials include polymers or small molecules that can transport charge carriers.
  • LEP layer 420 may also include semiconductors, such as silicon or gallium arsenide.
  • the LEP layer 420 has a thickness of greater than 80 nm and preferably, between 80 and 200 nm. "Thickness of the LEP layer" as used in describing this and other embodiments of the invention, refers to the distance between bottom of the second electrode 423 and the top of the HTL 417 in a vertical direction.
  • the thicker LEP layer 420 has been shown to increase the photopic efficiency and lifetime of device 420.
  • the combined thickness of the layers in the organic stack i.e. LEP layer 420, interlayer 418 and HTL 417, is held at a constant such that the individual layer thicknesses could be optimized without an undue increase in overall thickness.
  • All of the organic layers such as FITL 417, interlayer 418 and LEP layer 420 can be ink-jet printed by depositing an organic solution or by spin-coating, or other deposition techniques.
  • This organic solution may be any "fluid" or deformable mass capable of flowing under pressure and may include solutions, inks, pastes, emulsions, dispersions and so on.
  • the liquid may also contain or be supplemented by further substances which affect the viscosity, contact angle, thickening, affinity, drying, dilution and so on of the deposited drops.
  • the LEP layer 420 is fabricated by depositing this solution, using either a selective or non-selective deposition technique, onto HTL 417. To obtain a thicker LEP layer 420, in accordance with the invention, more drops or a greater concentration of polymer solution or a slower rotational speed while spin coating is required to be deposited. Further, each of the layers 417, 418 and 420 may be cross-linked or otherwise physically or chemically hardened as desired for stability and maintenance of certain surface properties desirable for deposition of subsequent layers.
  • second electrode 423 functions as a cathode when an electric potential is applied across the first electrode 411 and second electrode 423.
  • first electrode 41 1 which serves as the anode
  • second electrode 423 which serves as the cathode
  • photons are released from active electronic layer 420 that pass through first electrode 41 1 and substrate 408.
  • materials, which can function as a cathode are known to those of skill in the art, most preferably a composition that includes aluminum, indium, silver, gold, magnesium, calcium, and barium, or combinations thereof, or alloys thereof, is utilized. Aluminum, aluminum alloys, and combinations of magnesium and silver or their alloys can also be utilized.
  • the thickness of second electrode 423 is from about 10 to about 1000 nanometers (nm), more preferably from about 50 to about 500 nm, and most preferably from about 100 to about 300 nm. While many methods are known to those of ordinary skill in the art by which the first electrode material may be deposited, vacuum deposition methods, such as physical vapor deposition (PND) are prefetred. Other layers (not shown) such as a banner layer and getter layer may also be used to protect the electronic device. Such layers are well-known in the art and are not specifically discussed herein. Often other steps such as washing and neutralization of films, the addition of masks and photo-resists may precede the cathode deposition.
  • PND physical vapor deposition
  • FIG. 5 illustrates the effects of a thin HTL layer in various device structures in accordance with at least one embodiment of the invention.
  • the three curves of FIG. 5 illustrate results of measurements taken on three different devices.
  • the first device (I) had a conventional thickness HTL along with interlayer and conventional thickness LEP layer.
  • the second device (II) had a thin HTL along with an interlayer and conventional thickness LEP layer.
  • the third device (III) had a thin HTL, interlayer and a thick LEP layer.
  • Device III showed an over 400% improvement (over device I) in lifetime at half of initial luminance.
  • Device II shows a 155% improvement (over device I) in lifetime at half initial luminance.
  • the embodiments of a thicker LEP layer and interlayer combination are illustrated in which it is incorporated within an OLED device, this concept may be applied to other electronic devices that use an active electronic layer.
  • the light responsive layer i.e., the active electronic layer
  • the active electronic layer can be comprised of a thick film polymer.
  • the OLED device described earlier can be used in applications such as, for example, computer displays, information displays in vehicles, television monitors, telephones, printers, and illuminated signs, general lighting, night lights, and backlights.
  • applications such as, for example, computer displays, information displays in vehicles, television monitors, telephones, printers, and illuminated signs, general lighting, night lights, and backlights.

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Electroluminescent Light Sources (AREA)
  • Luminescent Compositions (AREA)
  • Led Devices (AREA)

Abstract

L'invention concerne un dispositif à diode électroluminescente organique formée d'une couche polymère à émission de lumière épaisse, une couche de transport de trou et une intercouche entre la couche à émission de lumière épaisse et la couche de transport de trou.
PCT/EP2005/003331 2004-03-30 2005-03-30 Structure de dispositif destinee a ameliorer la fiabilite d'une diode electroluminescente organique (oled) Ceased WO2005096401A2 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
US55746404P 2004-03-30 2004-03-30
US60/557,464 2004-03-30
US86914704A 2004-06-15 2004-06-15
US10/869,147 2004-06-15
US10/895,862 2004-07-20
US10/895,862 US20060017057A1 (en) 2004-07-20 2004-07-20 Device structure to improve OLED reliability

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WO2005096401A2 true WO2005096401A2 (fr) 2005-10-13
WO2005096401A3 WO2005096401A3 (fr) 2005-11-10

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EP1811579A1 (fr) * 2006-01-18 2007-07-25 STMicroelectronics S.r.l. Structure d'optocoupleur galvanique et procédé d'intégration hybride correspondant

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US6670053B2 (en) * 2002-02-26 2003-12-30 Eastman Kodak Company Organic electroluminescent devices with high luminance

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