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
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof

Definitions

• An electroluminescent (EL) arrangement is characterized in that it emits light under current flow when an electrical voltage is applied.
• Such arrangements have long been known in the art under the name “light emitting diodes” (LEDs).
• the emission of light comes about by the fact that positive charges (“holes”, holes) and negative charges (“electrons”, electrons) combine while emitting light.
• the LEDs commonly used in technology all consist predominantly of inorganic semiconductor materials.
• EL arrangements have been known for some years, the essential components of which are organic materials.
• organic EL arrangements usually contain one or more layers of organic charge transport compounds.
• the basic structure is shown in Figure 1.
• the numbers 1 to 10 mean:
• an EL arrangement consists of two electrodes, between which there is an organic layer that fulfills all functions, including the emission of light.
• organic layer that fulfills all functions, including the emission of light.
• the invention now relates to electroluminescent arrangements with one or more organic layers which contain at least one layer or one or more liquid-crystalline charge transport compounds.
• organic layers correspond to layers 3 to 7 in FIG. 1; when setting up the EL arrangement, e.g. the electron conductor layer and the electron-injecting layer can be dispensed with.
• the EL arrangement would then e.g. consist of layers 3 to 5.
• charge transport compounds are understood to mean all liquid-crystalline compounds which in some way transport charges (holes and / or electrons). This also explicitly includes those compounds which are components of the emitter layer, that is to say photoluminescent materials, such as e.g. Fluorescent dyes. Liquid crystalline photoconductors are e.g. described in European patent applications 527 376 AI and P 93104832.6.
• the charge transport compounds according to the invention can be low-molecular (“monomeric") liquid-crystalline compounds, oligomers, oligomer mixtures, polymers or polymer networks and mixtures of the compounds mentioned.
• liquid-crystalline charge transport compounds are discotically liquid-crystalline compounds from the series of triphenylenes, phthalocyanines, tricycloquinazolines, perylenes, peryleneimides, decacyclenes or porphyrins, and also calamitically liquid-crystalline from the series of oxadiazoles, thiadiazoles, biphenyls, ilipenyls, ilipenyls , Terphenyls, quaterphenyls or oxazolines.
• the liquid-crystalline charge transport compounds are preferably used for layers 4 and 6 or 3 and 7. They are particularly well suited for this because of their high charge carrier mobility in the liquid-crystalline phase.
• the liquid-crystalline charge transport compounds are particularly preferred in the molecular order present in a liquid-crystalline phase used. This order can be set, for example, by heating the sample. This order can be fixed, for example in the case of polymers which do not crystallize but solidify in a glass-like manner, by freezing into the glass state. It is also possible to fix the liquid-crystalline order by crosslinking in accordance with the method described in German patent application P 4339711.5.
• those layers which do not contain any liquid-crystalline charge-transporting compounds are produced in the customary manner, for example by vapor deposition of low molecular charge transport compounds or by pouring or spinning on solutions of low molecular charge transport compounds in a polymeric binder or directly from solutions of polymeric charge transport compounds or their precursors.
• Layers in which the components of the individual layers are thermally or particularly preferably crosslinked with actinic radiation are particularly preferred. This can e.g. similar to the methods described in German patent applications P 4325885.9 and P 4339711.5.
• the liquid-crystalline charge transport compound is then in the isotropic phase, i.e. e.g. poured as a thin melt.
• the glass plates can have other layers (e.g. orientation layers), which, however, must be thermally so stable that they are not destroyed when the liquid-crystalline charge transport compound, which may be hot, is filled.
• Networked layers as in the German
• Patent application P 4325885.9 are generally suitable.
• liquid crystalline charge transport bond expediently applied to the substrate from solution, for example by casting or spin coating; application in bulk is of course also possible with a sufficiently low melting point.
• the liquid-crystalline order can generally be set by simply heating the sample to convert it to the isotropic state and then cooling it to form the liquid-crystalline phase.
• the liquid-crystalline order can be frozen in the glass state by quenching or fixed by crosslinking (see also German patent application P 43 39 711.5).
• the layers which contain one or more of the liquid-crystalline compounds according to the invention can additionally contain one or more auxiliaries.
• auxiliaries e.g. non-liquid crystalline charge transport compounds, e.g. Emitter dyes, or polymerization initiators and leveling agents, as are known to the person skilled in the art from coating technology.
• FIG. 2 A diagram of the arrangement is shown in FIG. 2, the designations are explained in the following text:
• a solution of 50 mg oxadiazole and 100 mg poly [cinnamic acid vinyl ester] in 1070 mg toluene was first spun onto a glass substrate ("1") vapor-coated with aluminum (20 nm, "2" in FIG. 2). The layer was then crosslinked by exposure to an HBO lamp for five minutes (* 3'1.
• the cavity of the resulting arrangement was finally filled with hexapentyloxytriphenylene at 130 ° C ("7").
• the electroluminescence of this probe was observed at 80 ° C. At this temperature, hexapentyloxytriphenylene is present in the liquid-crystalline DO phase. The light emitted was orange-red at a voltage of 150 V.
• Hexapentyloxytriphenylene (phase sequence k 69 ° C Dho 122 ° C i) is diffused into a cell (see FIG. 3) at a temperature of 130 ° C.
• the cell consists of a cross-shaped arrangement of two electrodes on glass substrates (see FIG. 3), one of which consists of transparent indium tin oxide (ITO) and the other of aluminum (thickness: 60 nm).
• the active area is approximately 2 mm x 2 mm with a thickness of approximately 1.3 ⁇ m.
• the two electrodes After the cell has been filled, the two electrodes are contacted with a conductive two-component adhesive. After applying a voltage of 69 V (positive to ITO) at a temperature of 80 ° C, the arrangement lights up bluish. The emission can be clearly seen in a dark room. Even after a few hours of lighting, no decrease in brightness is discernible.
• the substance 2 capable of forming liquid-crystalline phases is allowed to diffuse into a cell (see FIG. 3) at a temperature of 120 ° C.
• the phase sequence is g34 ° Ck66 ° Cnl02 ° Ci.
• the cell consists of a cross-shaped arrangement of two electrodes, one of which consists of transparent indium-tin oxide and the other of aluminum (thickness: 60 nm).
• the active area is approximately 2 mm x 2 mm with a thickness of approximately 3.0 ⁇ m.
• the two electrodes are contacted with a conductive two-component adhesive. After applying a DC voltage of 200 V (positive to ITO) at a temperature of 85 ° C, the arrangement lights up bluish.
• Figure 3 mean: 1 glass, 2 aluminum, 3 ITO and 4 glue.
• 2,3,6,7, 10, 11-Hexabutyl-oxytriphenylene is allowed to flow into a cell analogous to Example 2 at a temperature of 155 ° C., after contacting as described in Example 2, the cell is adjusted to adjust the isotropic phase up to heated to a temperature of 155 ° C and cooled to 118 ° C after a waiting time of 5 minutes at a cooling rate of 1 K / min.
• a DC voltage of 45 V ITO electrode positive, aluminum electrode negative, the arrangement lights up orange. No light emission can be observed at a voltage of 5 V.
• the isotropic phase is adjusted by heating to a temperature of 120 ° C., and after a waiting time of 5 minutes, the mixture is cooled to 60 ° C. at a cooling rate of 1 K / min.
• a DC voltage of 40 V, ITO electrode positive, aluminum electrode negative is applied, the arrangement lights up orange. At a voltage of 5 V, no light emission can be observed.
• the isotropic phase is adjusted by heating to a temperature of 120 ° C., and after a waiting time of 5 minutes, the mixture is cooled to 20 ° C. at a cooling rate of 1 K / min.
• a DC voltage of 65 V ITO electrode positive, aluminum electrode negative, the arrangement lights up orange. No light emission can be observed at a voltage of 5 V.
• the isotropic phase is set at a temperature of 150 ° C. and after a waiting time of 5 minutes, the mixture is cooled to 100 ° C. at a cooling rate of 1 K / min.
• a DC voltage of 50 V ITO electrode positive, aluminum electrode negative, the arrangement lights up orange. At a voltage of 5 V, no light emission can be observed.

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• Physics & Mathematics (AREA)
• Condensed Matter Physics & Semiconductors (AREA)
• Electromagnetism (AREA)
• General Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Computer Hardware Design (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Power Engineering (AREA)
• Optics & Photonics (AREA)
• Electroluminescent Light Sources (AREA)
• Liquid Crystal Substances (AREA)

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• 1993
  • 1993-12-18 DE DE4343412A patent/DE4343412A1/de not_active Withdrawn
• 1994
  • 1994-12-08 EP EP95903326A patent/EP0734592A1/de not_active Withdrawn
  • 1994-12-08 JP JP7516507A patent/JPH09506646A/ja active Pending
  • 1994-12-08 KR KR1019960703226A patent/KR960706693A/ko not_active Application Discontinuation
  • 1994-12-08 CN CN94194540A patent/CN1137841A/zh active Pending
  • 1994-12-08 WO PCT/EP1994/004076 patent/WO1995017018A1/de not_active Application Discontinuation

Non-Patent Citations (1)

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