WO2012161005A1 - Élément électroluminescent organique - Google Patents

Élément électroluminescent organique Download PDF

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Publication number
WO2012161005A1
WO2012161005A1 PCT/JP2012/062255 JP2012062255W WO2012161005A1 WO 2012161005 A1 WO2012161005 A1 WO 2012161005A1 JP 2012062255 W JP2012062255 W JP 2012062255W WO 2012161005 A1 WO2012161005 A1 WO 2012161005A1
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WIPO (PCT)
Prior art keywords
electrode
layer
organic electroluminescence
carrier
substrate
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PCT/JP2012/062255
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English (en)
Japanese (ja)
Inventor
将啓 中村
正人 山名
矢口　充雄
山木　健之
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パナソニック株式会社
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Publication of WO2012161005A1 publication Critical patent/WO2012161005A1/fr

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    • 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
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/80—Constructional details
    • H10K59/805—Electrodes
    • H10K59/8051—Anodes
    • H10K59/80515—Anodes characterised by their shape
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/80—Constructional details
    • H10K59/805—Electrodes
    • H10K59/8051—Anodes
    • H10K59/80516—Anodes combined with auxiliary electrodes, e.g. ITO layer combined with metal lines
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/80—Constructional details
    • H10K59/805—Electrodes
    • H10K59/8052—Cathodes
    • H10K59/80521—Cathodes characterised by their shape
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/80—Constructional details
    • H10K59/805—Electrodes
    • H10K59/8052—Cathodes
    • H10K59/80522—Cathodes combined with auxiliary electrodes

Definitions

  • the present invention relates to an organic electroluminescence element.
  • an organic electroluminescence element having the structure shown in FIG. 7 has been proposed (for example, Japanese Patent Publication No. 2006-331694; see Patent Document 1).
  • this organic electroluminescence element one electrode (cathode) 101 is laminated on the surface of the substrate 104, a light emitting layer 103 is laminated on the surface of the electrode 101 via an electron injection / transport layer 105, and on the light emitting layer 103.
  • the other electrode (anode) 102 is laminated via the hole injection / transport layer 106.
  • the organic electroluminescence element includes a sealing member 107 on the surface side of the substrate 104. Therefore, in this organic electroluminescence element, light emitted from the light emitting layer 103 is radiated through the electrode 102 formed as a light transmissive electrode and the sealing member 107 formed of a transparent body.
  • Examples of the material of the reflective electrode 101 include Al, Zr, Ti, Y, Sc, Ag, and In.
  • Examples of the material of the electrode 102 which is a light transmissive electrode include indium-tin oxide (ITO) and indium-zinc oxide (IZO).
  • the organic electroluminescence element In order to light the organic electroluminescence element with high brightness, it is necessary to pass a larger current.
  • the organic electroluminescence element generally has a higher sheet resistance of an anode made of an ITO film than that of a cathode made of a metal film, an alloy film, a metal compound film, etc., the potential gradient at the anode is high. As a result, the in-plane variation in luminance increases.
  • Patent Document 2 includes a first conductive layer 220, an electroluminescent material 230, a second conductive layer 240, and a substrate 245, and the first conductive layer 220 has a rectangular shape.
  • An electroluminescent lamp 210 composed of a rectangular grid electrode having openings 250 has been proposed.
  • Patent Document 2 describes that it is preferable to form the first conductive layer 220 and the second conductive layer 240 with conductive ink such as silver ink or carbon ink.
  • Patent Document 2 describes that the first conductive layer 220, the electroluminescent material 230, and the second conductive layer 240 are formed by a screen printing method, an offset printing method, or the like.
  • Patent Document 2 describes that when the electroluminescence lamp 210 having uniform brightness is required, the density of the openings 250 is made substantially constant over the surface of the lamp.
  • the first conductive layer 220 has the opening 250, and thus the first conductive layer 220 in the electroluminescent material 230 has the first conductive layer 220.
  • Carriers are injected only into the portion immediately below the layer 220. For this reason, in the electroluminescence lamp 210, there is a concern that the light emission efficiency at the portion corresponding to the opening 250 in the electroluminescence material 230 is lowered, and the external quantum efficiency is lowered.
  • the present invention has been made in view of the above reasons, and an object of the present invention is to provide an organic electroluminescence device capable of reducing luminance unevenness and improving external quantum efficiency. is there.
  • the organic electroluminescence device of the present invention includes a substrate, a first electrode provided on one surface side of the substrate, a second electrode facing the first electrode on the one surface side of the substrate, and the first electrode
  • An organic electroluminescence element comprising a functional layer including a light emitting layer between an electrode and the second electrode, wherein the resistivity of each of the first electrode and the second electrode is a transparent conductive oxide Lower than resistivity, the functional layer is the outermost layer on the second electrode side than the light emitting layer, and the first carrier injected from the first electrode to the functional layer is directed to the second electrode side.
  • a first carrier blocking layer that suppresses leakage; and the second electrode has an opening for extracting light from the functional layer, and the opening includes the second electrode and the functional layer.
  • Second carrier injection function A conductive layer having light transparency is provided, the conductive layer covers the second electrode, and the first carrier blocking layer is provided with a recess in a projection region of the opening. And
  • the distance from the projection region of the second electrode to the inner surface close to the projection region increases as the recess moves away from the second electrode in the thickness direction of the first carrier blocking layer. It is preferably formed in a shape.
  • the second electrode is preferably composed of an electrode containing a metal powder and an organic binder.
  • the conductive layer is preferably formed of a transparent conductive film including a conductive nanostructure and a transparent medium.
  • the first carrier blocking layer has a thickness of a projection region of the opening portion smaller than a thickness of a projection region of the second electrode.
  • the organic electroluminescence device of the present invention it is possible to reduce luminance unevenness and improve external quantum efficiency.
  • FIG. 1 is a schematic cross-sectional view of an organic electroluminescence element of Embodiment 1.
  • FIG. 3 is a schematic plan view of a second electrode in the organic electroluminescence element of Embodiment 1.
  • FIG. 2 is a schematic cross-sectional view of a main part of the organic electroluminescence element of Embodiment 1.
  • FIG. 6 is a schematic plan view of another configuration example of the second electrode in the organic electroluminescence element of Embodiment 1.
  • FIG. 6 is a schematic plan view of another configuration example of the second electrode in the organic electroluminescence element of Embodiment 1.
  • FIG. 1 is a schematic cross-sectional view of an organic electroluminescence element of Embodiment 1.
  • FIG. 3 is a schematic plan view of a second electrode in the organic electroluminescence element of Embodiment 1.
  • FIG. 2 is a schematic cross-sectional view of a main part of the organic electroluminescence element of Embodiment 1.
  • FIG. 6 is a
  • FIG. 5 is a schematic cross-sectional view of a main part of an organic electroluminescence element of Embodiment 2.
  • FIG. It is a schematic sectional drawing of the organic electroluminescent element of a prior art example. It is a see-through
  • the organic electroluminescence element includes a substrate 10, a first electrode 20 provided on one surface side (the upper side in FIG. 1) of the substrate 10, and a second electrode facing the first electrode 20 on the one surface side of the substrate 10. 40 and a functional layer 30 including the light emitting layer 32 between the first electrode 20 and the second electrode 40.
  • the electroluminescent element of the present embodiment includes the first electrode 20 and the second electrode 40 that are disposed to face each other, and the functional layer 30 that is disposed between the first electrode 20 and the second electrode 40. ing.
  • the organic electroluminescence element has a first terminal portion (not shown) electrically connected to the first electrode 20 via a first lead wiring (not shown), and a second lead to the second electrode 40. And a second terminal portion 47 electrically connected via the wiring 46.
  • the first lead wiring, the first terminal portion, the second lead wiring 46 and the second terminal portion 47 are provided on the one surface side of the substrate 10.
  • an insulating film 60 that electrically insulates the second lead wiring 46 from the functional layer 30, the first electrode 20, and the first lead wiring is provided on the one surface side of the substrate 10. .
  • the insulating film 60 is formed across the one surface of the substrate 10, the side surface of the first electrode 20, the side surface of the functional layer 30, and the outer peripheral portion of the surface of the functional layer 30 on the second electrode 40 side.
  • the organic electroluminescence element has a resistivity (electrical resistivity) of each of the first electrode 20 and the second electrode 40 that is higher than a resistivity (electrical resistivity) of a transparent conductive oxide (TCO). It is low.
  • the transparent conductive oxide include ITO, AZO, GZO, and IZO.
  • the resistivity of such a transparent conductive oxide is not particularly limited, but is exemplified as 1 ⁇ 10 ⁇ 4 to 1 ⁇ 10 ⁇ 3 ⁇ ⁇ cm.
  • the functional layer 30 is the outermost layer on the second electrode 40 side with respect to the light emitting layer 32, and the second carrier 40 side of the first carrier injected from the first electrode 20 into the functional layer 30.
  • the first carrier blocking layer 33 that suppresses leakage to the substrate is included.
  • the second electrode 40 is formed with an opening 41 for extracting light from the functional layer 30. That is, in the organic electroluminescence element, the second electrode 40 has an opening 41 (see FIGS. 2 and 3) for extracting light from the functional layer 30.
  • the organic electroluminescence element is provided with a conductive layer 50 which is in contact with the second electrode 40 and the functional layer 30 (first carrier blocking layer 33) and has a second carrier injection function and light transmittance. Thereby, the organic electroluminescence element can extract light from the second electrode 40 side.
  • the organic electroluminescence element of the present embodiment can be used as a top emission type organic electroluminescence element.
  • the conductive layer 50 covers the second electrode 40.
  • the conductive layer 50 of the present embodiment covers the second electrode 40 and the first carrier blocking layer 33.
  • the first carrier blocking layer 33 is provided with a recess 38 in the projection area of the opening 41.
  • the organic electroluminescence element has a cover substrate 70 that is disposed opposite to the one surface side of the substrate 10 and has translucency, and a frame shape (this embodiment) interposed between the peripheral portion of the substrate 10 and the peripheral portion of the cover substrate 70.
  • a frame portion 80 having a rectangular frame shape.
  • the organic electroluminescence element includes the element portion 1 including the first electrode 20, the functional layer 30, the second electrode 40, the conductive layer 50, and the like in a space surrounded by the substrate 10, the cover substrate 70, and the frame portion 80.
  • a sealing portion 90 made of a light-transmitting material (for example, a light-transmitting resin) to be sealed.
  • the substrate 10 has a rectangular shape in plan view.
  • the planar view shape of the substrate 10 is not limited to a rectangular shape, and may be, for example, a polygonal shape or a circular shape other than the rectangular shape.
  • the glass substrate is used as the substrate 10, but is not limited thereto, and for example, a plastic plate or a metal plate may be used.
  • a material for the glass substrate for example, soda lime glass, non-alkali glass, or the like can be employed.
  • a material of the plastic plate for example, polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polycarbonate, or the like can be employed.
  • a material of the metal plate for example, aluminum, copper, stainless steel, or the like can be employed.
  • the substrate 10 may be rigid or flexible.
  • the unevenness on the one surface of the substrate 10 may cause a leak current of the organic electroluminescence element (may cause deterioration of the organic electroluminescence element). .
  • the arithmetic average roughness Ra specified in JIS B 0601-2001 is preferably 10 nm or less, and preferably several nm or less. More preferable.
  • a plastic plate is used as the substrate 10, it is possible to obtain at low cost an arithmetic average roughness Ra of one surface or less of the above-mentioned surface without particularly high precision polishing. It is.
  • the glass substrate is used as the cover substrate 70, but is not limited thereto, and for example, a plastic plate or the like may be used.
  • a material for the glass substrate for example, soda lime glass, non-alkali glass, or the like can be employed.
  • a material of the plastic plate for example, polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polycarbonate, or the like can be employed.
  • a flat substrate is used as the cover substrate 70, but is not limited to this, and a substrate in which a storage recess for storing the above-described element unit 1 is formed on the surface facing the substrate 10 is used.
  • the peripheral portion of the storage recess on the facing surface may be joined to the substrate 10 side over the entire circumference.
  • a box-shaped cover substrate 70 having an open surface may be used, the element unit 1 may be accommodated inside the cover substrate 70, and the peripheral edge of the opening of the cover substrate 70 may be bonded to the substrate 10 side.
  • the frame part 80 which is a separate member.
  • a light extraction structure (not shown) that suppresses reflection of light emitted from the light emitting layer 32 on the outer surface.
  • Examples of such a light extraction structure part include an uneven structure part having a two-dimensional periodic structure.
  • the period of such a two-dimensional periodic structure is such that when the wavelength of light emitted from the light emitting layer 32 is in the range of 300 to 800 nm, for example, the wavelength in the medium is ⁇ (the wavelength in vacuum is divided by the refractive index of the medium). Value), it is desirable to set appropriately within the range of 1/4 to 10 times the wavelength ⁇ .
  • Such an uneven structure portion is formed in advance on the outer surface side of the cover substrate 70 by, for example, an imprint method such as a thermal imprint method (thermal nanoimprint method) or an optical imprint method (photo nanoimprint method). It is possible. Further, depending on the material of the cover substrate 70, the cover substrate 70 may be formed by injection molding, and the uneven structure portion may be directly formed on the cover substrate 70 by using an appropriate mold at the time of injection molding. Further, the concavo-convex structure portion can also be configured by a member different from the cover substrate 70, for example, a prism sheet (for example, a light diffusion film such as Lightup (registered trademark) GM3 manufactured by Kimoto Co., Ltd.). Can be configured.
  • an imprint method such as a thermal imprint method (thermal nanoimprint method) or an optical imprint method (photo nanoimprint method). It is possible.
  • the cover substrate 70 may be formed by injection molding, and the uneven structure portion may be directly formed on the cover substrate 70 by using an appropriate mold at the
  • the organic electroluminescence element of this embodiment by providing the above-described light extraction structure portion, it is possible to reduce the reflection loss of the light emitted from the light emitting layer 32 and reaching the outer surface side of the cover substrate 70, and to improve the light extraction efficiency. Can be achieved.
  • the first bonding material is not limited thereto, and for example, an acrylic resin may be used.
  • the epoxy resin or acrylic resin used as the first bonding material may be, for example, an ultraviolet curable type or a thermosetting type.
  • you may use what made the epoxy resin contain a filler (for example, a silica, an alumina, etc.) as a 1st joining material.
  • the frame portion 80 is airtightly bonded to the one surface side of the substrate 10 over the entire periphery of the surface of the frame portion 80 facing the substrate 10 side.
  • the frame portion 80 is airtightly bonded to the cover substrate 70 over the entire circumference of the surface of the frame portion 80 facing the cover substrate 70.
  • polyimide As a material of the insulating film 60, for example, polyimide, novolac resin, epoxy resin, or the like can be used.
  • the translucent material that is a material of the sealing portion 90 for example, a translucent resin such as an epoxy resin or a silicone resin can be used, but a material having a small refractive index difference from the functional layer 30 is more preferable.
  • the light transmissive material may be a light transmissive resin mixed with a light diffusing material made of glass or the like.
  • an organic / inorganic hybrid material in which an organic component and an inorganic component are mixed and bonded at the nm level or molecular level may be used.
  • the first electrode 20 constitutes a cathode and the second electrode 40 constitutes an anode.
  • the functional layer 30 includes a first carrier injection layer 31, a light emitting layer 32, and a first carrier blocking layer 33 in order from the first electrode 20 side.
  • a first carrier injection layer 31 is formed in contact with the first electrode 20.
  • a light emitting layer 32 is formed in contact with the first carrier injection layer 31.
  • a first carrier blocking layer 33 is formed in contact with the light emitting layer 32.
  • the second electrode 40 is formed in contact with the first carrier blocking layer 33.
  • the first carrier injected from the first electrode 20 into the functional layer 30 is an electron
  • the second carrier injected from the second electrode 40 into the functional layer 30 is a hole
  • the first carrier injection layer 31 on the first electrode 20 side in the light emitting layer 32 is an electron injection layer.
  • the 1st carrier blocking layer 33 is an interlayer and is comprised with an electronic blocking layer.
  • a hole injection layer is adopted as the first carrier injection layer 31 and the first carrier blocking layer 33 is formed as an interface. What is necessary is just to comprise a layer by a hole blocking layer.
  • the structure of the above-described functional layer 30 is not limited to the above-described example.
  • a first carrier transport layer here, an electron transport layer
  • a second carrier transport layer here, a hole transport layer
  • the functional layer 30 only needs to include the light emitting layer 32 and the first carrier blocking layer 33 (that is, the functional layer 30 may be only the light emitting layer 32 and the first carrier blocking layer 33).
  • the first carrier injection layer 31, the first carrier transport layer, the second carrier transport layer, and the like other than 32 and the first carrier blocking layer 33 may be provided as appropriate.
  • the light emitting layer 32 may have a single layer structure or a multilayer structure.
  • the emission layer may be doped with three types of dopant dyes of red, green, and blue, or the blue hole-transporting emission layer and the green electron-transporting property.
  • a laminated structure of a light emitting layer and a red electron transporting light emitting layer may be adopted, or a laminated structure of a blue electron transporting light emitting layer, a green electron transporting light emitting layer and a red electron transporting light emitting layer may be adopted. Good.
  • Examples of the material of the light emitting layer 32 include polyparaphenylene vinylene derivatives, polythiophene derivatives, polyparaphenylene derivatives, polysilane derivatives, polyacetylene derivatives, and the like, polyfluorene derivatives, polyvinylcarbazole derivatives, dye bodies, and metal complex light emitting materials.
  • the light emitting layer 32 is preferably formed by a wet process such as a coating method (for example, spin coating method, spray coating method, die coating method, gravure printing method, screen printing method, etc.).
  • a coating method for example, spin coating method, spray coating method, die coating method, gravure printing method, screen printing method, etc.
  • the method for forming the light emitting layer 32 is not limited to the coating method, and the light emitting layer 32 may be formed by a dry process such as a vacuum deposition method or a transfer method.
  • the material for the electron injection layer examples include metal fluorides such as lithium fluoride and magnesium fluoride, metal halides such as sodium chloride and magnesium chloride, titanium, zinc, magnesium, calcium, An oxide such as barium or strontium can be used.
  • the electron injection layer can be formed by a vacuum deposition method.
  • an organic semiconductor material mixed with a dopant (such as an alkali metal) that promotes electron injection can be used.
  • the electron injection layer can be formed by a coating method.
  • the material for the electron transport layer can be selected from the group of compounds having electron transport properties.
  • this type of compound include metal complexes known as electron transport materials such as Alq 3 and compounds having a heterocycle such as phenanthroline derivatives, pyridine derivatives, tetrazine derivatives, oxadiazole derivatives, etc. Instead, any generally known electron transport material can be used.
  • a low molecular material or a polymer material having a low LUMO (Lowest Unoccupied Molecular Molecular) level can be used.
  • examples thereof include polymers containing aromatic amines such as polyvinyl carbazole (PVCz), polyarylene derivatives such as polypyridine and polyaniline, and polyarylene derivatives having aromatic amines in the main chain, but are not limited thereto.
  • Examples of the material for the hole transport layer include 4,4′-bis [N- (naphthyl) -N-phenyl-amino] biphenyl ( ⁇ -NPD) and N, N′-bis (3-methylphenyl).
  • TPD -(1,1'-biphenyl) -4,4'-diamine
  • 2-TNATA 4,4 ', 4 "-tris (N- (3-methylphenyl) N-phenylamino) triphenylamine (MTDATA), 4,4′-N, N′-dicarbazole biphenyl (CBP), spiro-NPD, spiro-TPD, spiro-TAD, TNB, and the like can be used.
  • the first carrier blocking layer 33 is carrier blocking as a first carrier barrier (here, an electron barrier) that suppresses leakage of first carriers (here, electrons) from the light emitting layer 32 side to the second electrode 40 side. It has a function (here, an electronic blocking function).
  • the first carrier blocking layer 33 preferably has a function of transporting second carriers (here, holes) to the light emitting layer 32, a function of suppressing quenching of the excited state of the light emitting layer 32, and the like. .
  • the first carrier blocking layer 33 In the organic electroluminescence element, by providing the first carrier blocking layer 33, it is possible to improve the light emission efficiency and extend the life.
  • a material of the first carrier blocking layer 33 for example, polyarylamine or a derivative thereof, polyfluorene or a derivative thereof, polyvinylcarbazole or a derivative thereof, a triphenyldiamine derivative, or the like can be used.
  • Such a first carrier blocking layer 33 can be formed by a wet process such as a coating method (spin coating method, spray coating method, die coating method, gravure printing method, etc.) or a vacuum deposition method.
  • the first carrier blocking layer 33 has the recess 38 in the projection region of the opening 41.
  • the thickness of the projection region of the opening 41 is thinner than the thickness of the projection region of the second electrode 40.
  • the depth dimension of the recess 38 is smaller than the thickness dimension of the projection region of the second electrode 40 in the first carrier blocking layer 33 (that is, no through hole is formed in the first carrier blocking layer 33 by the recess 38. ) Is preferable, but the numerical values are not particularly limited.
  • Such a concave portion 38 can be formed by, for example, twice coating by a screen printing method, a gravure printing method, a spray coating method, or the like.
  • the cathode is an electrode for injecting electrons as the first charge into the functional layer 30.
  • the first electrode 20 injects electrons, which are first charges, into the functional layer 30 as first carriers.
  • the cathode material it is preferable to use an electrode material made of a metal, an alloy, an electrically conductive compound and a mixture thereof having a small work function, so that the difference from the LUMO (Lowest Unoccupied Molecular Orbital) level does not become too large. It is preferable to use a material having a work function of 1.9 eV or more and 5 eV or less.
  • the electrode material for the cathode examples include aluminum, silver, magnesium, gold, copper, chromium, molybdenum, palladium, tin, and alloys of these with other metals, such as magnesium-silver mixture, magnesium-indium mixture, aluminum -Lithium alloys can be mentioned as examples. Also, a metal, a metal oxide, etc., and a mixture of these and other metals, for example, an ultrathin film made of aluminum oxide (here, a thin film of 1 nm or less capable of flowing electrons by tunnel injection) and aluminum. A laminated film with a thin film can also be used.
  • the cathode material is preferably a metal having a high reflectance with respect to light emitted from the light emitting layer 32 and a low resistivity, and preferably aluminum or silver.
  • the material of the anode that is the first electrode 20 is: It is preferable to use a metal having a large work function, and it is preferable to use a metal having a work function of 4 eV or more and 6 eV or less so that the difference from the HOMO (Highest Occupied Molecular Orbital) level does not become too large.
  • HOMO Highest Occupied Molecular Orbital
  • the second electrode 40 is made of an electrode containing metal powder and an organic binder.
  • this type of metal for example, silver, gold, copper or the like can be employed.
  • the organic electroluminescence element can reduce the resistivity and sheet resistance of the second electrode 40 as compared with the case where the second electrode 40 is a thin film formed of a transparent conductive oxide. It is possible to reduce luminance unevenness by reducing the resistance of the two electrodes 40.
  • the conductive material of the second electrode 40 an alloy, carbon black, or the like can be used instead of a metal.
  • the second electrode 40 can be formed, for example, by printing a paste (printing ink) in which an organic binder and an organic solvent are mixed in a metal powder by, for example, a screen printing method or a gravure printing method.
  • the organic binder include acrylic resin, polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, polystyrene, polyether sulfone, polyarylate, polycarbonate resin, polyurethane, polyacrylonitrile, polyvinyl acetal, polyamide, polyimide, and diacryl phthalate resin.
  • Cellulose resins Polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, other thermoplastic resins, and copolymers of two or more monomers constituting these resins, but are not limited thereto. It is not something.
  • the first electrode 20 has a thickness of 80 to 200 nm
  • the first carrier injection layer 31 has a thickness of 5 to 50 nm
  • the light emitting layer 32 has a thickness of 60 to 100 nm
  • the film thickness of the part which overlaps with the 2nd electrode 40 in 1 carrier blocking layer 33 is each set to 40 nm, these numerical values are examples and are not specifically limited.
  • the second electrode 40 is formed in a lattice shape (mesh shape) and has a plurality of openings (36 in the example shown in FIG. 2). That is, the second electrode 40 of the present embodiment includes a plurality of thin wire portions 44 extending in the first direction (vertical direction in FIG. 2), and a second direction (horizontal direction in FIG. 2) intersecting the first direction. And a plurality of thin line portions 44 extending in the direction. A space surrounded by the plurality of thin line portions 44 is an opening 41 for light extraction.
  • each opening 41 has a square shape.
  • the second electrode 40 shown in FIG. 2 is formed in a square lattice shape.
  • the second electrode 40 has, for example, a line width L1 (see FIG. 3) of 1 ⁇ m to 100 ⁇ m and a height H1 (see FIG. 3) regarding the dimensions of the square-lattice electrode pattern 40a constituting the second electrode 40. 50 nm to 100 ⁇ m and the pitch P 1 (see FIG. 3) may be set to 100 ⁇ m to 2000 ⁇ m. However, the numerical ranges of the line width L1, the height H1, and the pitch P1 of the electrode pattern 40a of the second electrode 40 are not particularly limited, and may be set as appropriate based on the planar size of the element portion 1.
  • the line width L1 of the electrode pattern 40a of the second electrode 40 is preferably narrow from the viewpoint of the utilization efficiency of the light emitted from the light emitting layer 32, and luminance unevenness is reduced by reducing the resistance of the second electrode 40. Therefore, it is preferable that the width is appropriately set based on the planar size of the organic electroluminescence element.
  • the height H1 of the second electrode 40 from the viewpoint of lowering the resistance of the second electrode 40, the use efficiency of the material of the second electrode 40 when the second electrode 40 is formed by a coating method such as a screen printing method. From the viewpoint of (material use efficiency), the viewpoint of the emission angle of light emitted from the functional layer 30, and the like, 100 nm or more and 10 ⁇ m or less are more preferable.
  • each opening 41 in the second electrode 40 has an opening shape in which the opening area gradually increases as the distance from the functional layer 30 increases, as shown in FIGS. 1 and 3. is there. That is, the thin wire portion 44 of the second electrode 40 is formed in a substantially trapezoidal shape in cross section, and thus, the opening shape of the opening portion 41 gradually increases as the distance from the functional layer 30 increases.
  • the organic electroluminescence element can increase the spread angle of the light emitted from the functional layer 30, and can further reduce the luminance unevenness.
  • the organic electroluminescence element can reduce reflection loss and absorption loss at the second electrode 40, and can further improve the external quantum efficiency.
  • each opening 41 is not limited to a square shape, and may be, for example, a rectangular shape, a regular triangle shape, or a regular hexagonal shape.
  • the second electrode 40 has a triangular lattice shape when each of the openings 41 has a regular triangular shape, and has a hexagonal lattice shape when each of the openings 41 has a regular hexagonal shape. .
  • the second electrode 40 is not limited to a lattice shape, and may be, for example, a comb shape or may be configured by two comb-shaped electrode patterns.
  • the number of the openings 41 is not particularly limited, and the number of the second electrodes 40 is not limited to a plurality, and may be one. For example, when the second electrode 40 has a comb shape or is configured by two comb-shaped electrode patterns, the number of openings 41 can be one.
  • the second electrode 40 may have a planar shape as shown in FIG. 4, for example. That is, in this example, the second electrode 40 has a constant line width of the linear thin line portion 44 in the electrode pattern 40a in plan view. As the center of the second electrode 40 is approached, the interval between the fine line portions 44 and 44 adjacent in the vertical direction and the interval between the fine line portions 44 and 44 adjacent in the horizontal direction are gradually reduced. That is, the second electrode 40 has a shape in which the opening area of the opening 41 becomes smaller as the distance from the peripheral part approaches the center part. In the organic electroluminescence element, the second electrode 40 has a planar shape as shown in FIG. 4, so that the second terminal portion 47 in the second electrode 40 is compared with the planar shape as shown in FIG. 2.
  • the organic electroluminescence element has the first terminal portion of the functional layer 30 as compared with the case where the planar shape as shown in FIG. 2 is obtained by making the planar shape of the second electrode 40 as shown in FIG.
  • the second electrode 40 may have a planar shape as shown in FIG. 5, for example.
  • the second electrode 40 has four first fine wire portions 42 that form the outer frame on the outermost periphery of the second electrode 40, and a first direction (FIG. 5) inside the outer frame. And a plurality of thin wire portions (third thin wire portions) extending in a second direction (the left-right direction in FIG. 5) intersecting the first direction inside the outer frame. 44).
  • the second electrode 40 has a line width of the first thin line portion 42 and a line width of one second thin line portion 43 at the center in the left-right direction in FIG. It is wider than the line width of the third thin line portion 44 between the two thin line portions 43.
  • the second electrode 40 has a planar shape as shown in FIG. 5, so that the second terminal portion 47 (see FIG. 1) of the second electrode 40 is compared with the planar shape as shown in FIG. 2. It is possible to improve the light emission efficiency in the central part far from the peripheral part, and it is possible to improve the external quantum efficiency.
  • the second electrode 40 has a planar shape as shown in FIG. 5, the height of the first thin wire portion 42 and the second thin wire portion 43 having a relatively wide line width is set higher than the height of the third thin wire portion 44. By increasing the height, the resistance of each of the first thin wire portion 42 and the second thin wire portion 43 can be further reduced.
  • the conductive layer 50 has a second carrier injection function (here, a hole injection function) and light transmittance.
  • a conductive layer 50 can be formed of, for example, a conductive nanostructure and a conductive polymer.
  • the conductive layer 50 is formed from, for example, a transparent conductive film including a conductive nanostructure and a transparent medium.
  • the conductive layer 50 having a hole injection function can be formed of a composite film in which a conductive nanostructure is mixed with the material of the hole injection layer.
  • the conductivity of the conductive layer 50 is lower than that of the second electrode 40.
  • the conductivity of the conductive layer 50 is higher than that of the second carrier injection layer 34.
  • the conductive layer 50 functions as a second carrier injection path from the second electrode 40 to the functional layer 30.
  • the second carrier is a hole when the second electrode 40 is an anode, and an electron when the second electrode 40 is a cathode.
  • the conductive layer 50 is not present, and the part immediately below the second electrode 40 is a part of the functional layer 30, and the opening 41 is buried by a part of the electrically insulating sealing part 90 instead of the conductive layer 50. In this case, it is assumed that the injection of the second carrier from the second electrode 40 to the functional layer 30 is performed only through the interface between the second electrode 40 and the functional layer 30.
  • the injection of the second carrier from the second electrode 40 to the functional layer 30 is performed by the first path passing through the interface between the second electrode 40 and the functional layer 30. This is performed both in the interface between the second electrode 40 and the conductive layer 50 and in the second path passing through the interface between the conductive layer 50 and the functional layer 30.
  • the thickness of the projection region of the opening 41 is the second electrode 40. It is thinner than the thickness of the projection area.
  • the organic electroluminescence element has higher conductivity and higher injectability of the second carrier with respect to the conductive layer 50 than the first carrier blocking layer 33.
  • the carrier injection through the second path has priority over the carrier injection through the first path.
  • the proportion of light blocked by the second electrode 40 in the light emitted from the light emitting layer 32 is reduced, so that the external quantum efficiency can be improved.
  • the second carrier moves from the second electrode 40 to the in-plane direction of the conductive layer 50 (in FIG. 1) when moving toward the light emitting layer 32. Left and right and front and rear direction). Therefore, in-plane variation of the current flowing through the light emitting layer 32 can be reduced.
  • the lower the resistivity of the conductive layer 50 the better the electrical conductivity from the second electrode 40 in the lateral direction (left and right and front and rear in FIG. 1), and the in-plane variation of the current flowing through the light emitting layer 32 is reduced. It is possible to reduce luminance unevenness.
  • conductive nanostructure conductive nanoparticles, conductive nanowires, or the like can be used.
  • the particle diameter of the conductive nanoparticles is preferably 1 to 100 nm.
  • the diameter of the conductive nanowire is preferably 1 to 100 nm.
  • the material for the conductive nanostructure for example, silver, gold, ITO, IZO and the like can be employed.
  • the binder that is a transparent medium include acrylic resin, polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, polystyrene, polyethersulfone, polyarylate, polycarbonate resin, polyurethane, polyacrylonitrile, polyvinyl acetal, polyamide, polyimide, diethylene.
  • a conductive polymer such as polythiophene, polyaniline, polypyrrole, polyphenylene, polyphenylene vinylene, polyacetylene, polycarbazole as the binder. These may be used alone or in combination.
  • the conductive layer 50 can further improve conductivity by adopting a conductive polymer as a binder.
  • a binder in order to improve electroconductivity, you may employ
  • examples of the material for the hole injection layer include organic materials including thiophene, triphenylmethane, hydrazoline, amyramine, hydrazone, stilbene, triphenylamine, and the like.
  • organic materials including thiophene, triphenylmethane, hydrazoline, amyramine, hydrazone, stilbene, triphenylamine, and the like.
  • polyvinyl carbazole, polyethylenedioxythiophene: polystyrene sulfonate (PEDOT: PSS), aromatic amine derivatives such as TPD, etc. these materials may be used alone, or two or more kinds of materials. May be used in combination.
  • the conductive layer 50 described above can be formed by a wet process such as a coating method (spray coating method, die coating method, gravure printing method, screen printing method, etc.).
  • a coating method spray coating method, die coating method, gravure printing method, screen printing method, etc.
  • the conductive layer 50 may be configured by a stacked structure of a hole injection layer formed on the first carrier blocking layer 33 and a light-transmitting conductive layer formed on the hole injection layer. Good.
  • the thickness of the hole injection layer is preferably smaller than the depth dimension of the recess 38.
  • the resistivity of each of the first electrode 20 and the second electrode 40 is lower than the resistivity of the transparent conductive oxide, An opening 41 for extracting light from the functional layer 30 is formed.
  • the functional layer 30 is the outermost layer on the second electrode 40 side with respect to the light emitting layer 32, and the first carrier injected from the first electrode 20 into the functional layer 30 is the first layer.
  • the 1st carrier blocking layer 33 which suppresses the leak to the 2 electrode 40 side is included.
  • the organic electroluminescent element of this embodiment is provided with the conductive layer 50 that is in contact with the second electrode 40 and the functional layer 30 (first carrier blocking layer 33) and has the second carrier injection function and light transmittance. It has been.
  • the conductive layer 50 covers the second electrode 40, and the first carrier blocking layer 33 is provided with a recess 38 in the projection region of the opening 41. Therefore, in the organic electroluminescence element of this embodiment, it is possible to reduce luminance unevenness and to improve external quantum efficiency.
  • the organic electroluminescence element of the present embodiment since the conductive layer 50 covers the second electrode 40, the second carrier 40 can be more injected from the second electrode 40 to the conductive layer 50. It becomes possible to improve.
  • the height (first height) from the light emitting layer 32 to the surface of the conductive layer 50 in the recess 38 is the height (second height) from the light emitting layer 32 to the tip of the second electrode 40.
  • the height is lower than (height).
  • the first height is the thickness between the inner bottom surface of the recess 38 and the light emitting layer 32 in the first carrier blocking layer 33 and the conductive layer 50 on the inner bottom surface of the recess 38.
  • the second height is a total value of the film thickness of the projection region of the second electrode 40 in the first carrier blocking layer 50 and the height H1 of the second electrode 40.
  • the organic electroluminescence element has the first height lower than the second height, so that the optical loss in the conductive layer 50 can be reduced, and the external quantum efficiency can be improved. It becomes possible.
  • the magnitude relationship between the film thickness of the conductive layer 50 and the depth dimension of the recess 38 is not particularly limited.
  • the organic electroluminescence element of this embodiment is substantially the same as that of Embodiment 1, and only the shape of the recess 38 is different as shown in FIG.
  • symbol is attached
  • the concave portion 38 is formed in a shape in which the distance from the projection region of the second electrode 40 to the inner side surface 38a close to the projection region increases as the distance from the second electrode 40 increases in the thickness direction of the first carrier blocking layer 33. .
  • the concave portion 38 is formed in a rectangular cross section, whereas in the example shown in FIG. 6, the concave portion 38 is formed in an inverted trapezoidal shape.
  • the projection region of the second electrode 40 is closer to the projection region. It is formed in a shape that increases the distance to the inner side surface 38a.
  • the thickness of the first carrier blocking layer 33 in the projection region of the opening 41 becomes thinner as the distance from the second electrode 40 increases.
  • the film thickness is gradually increased in the region where the distance from the projection region of the second electrode 40 is changed with respect to the projection region of the opening 41 in the first carrier blocking layer 33.
  • the first carrier blocking layer 33 is more likely to pass the second carrier as it is closer to the second electrode 40, but the second carrier is less likely to pass as the film thickness is larger, so the opening 41 in the first carrier blocking layer 33. It is possible to improve the uniformity of the carrier injection amount into the projection area, and to further reduce the luminance unevenness.
  • the first carrier blocking layer 33 is shown to have a constant thickness at a location that is a predetermined distance or more away from the second electrode 40 in the width direction of the second electrode 40 (left-right direction in FIG. 6). Yes.
  • the first carrier blocking layer 33 may have a shape in which the thickness gradually decreases with the distance from the second electrode 40.
  • the shape of the inner side surface 38a of the concave portion 38 is not limited to the planar shape as shown in FIG. 6, and may be a curved surface shape.
  • the cross-sectional shape of the recess 38 may be a kamaboko shape.
  • the organic electroluminescence element described in the first and second embodiments can be suitably used as an organic electroluminescence element for illumination, for example, but is not limited to illumination and can be used for other purposes.
  • each figure demonstrated in Embodiment 1, 2 is typical, and the ratio of each magnitude

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Electroluminescent Light Sources (AREA)

Abstract

Afin de fournir un élément électroluminescent organique qui est en mesure de réduire la luminosité irrégulière et qui est en mesure d'améliorer l'efficacité quantique externe, l'élément électroluminescent organique selon la présente invention est pourvu d'un substrat (10), d'une première électrode (20), de secondes électrodes (40), d'une couche fonctionnelle (30) qui se trouve entre la première électrode (20) et les secondes électrodes (40) et qui inclut une couche électroluminescente (32), et une couche conductrice (50). Les résistivités de la première électrode (20) et des secondes électrodes (40) sont inférieures à la résistivité d'un oxyde conducteur transparent. Des ouvertures permettant d'extraire la lumière sont formées sur les secondes électrodes (40). La couche fonctionnelle (30) inclut, en tant que couche extérieure du côté de la seconde électrode (40), une couche de blocage de premier porteur de charge (33) permettant de supprimer les fuites d'un premier porteur de charge, qui est injecté dans la couche fonctionnelle (30) à partir de la première électrode (20), vers le côté de la seconde électrode (40). La couche conductrice (50) est en contact avec les secondes électrodes (40) et la couche fonctionnelle (30) et est dotée d'une fonction d'injection de second porteur de charge et d'une transparence optique. La couche de blocage de premier porteur de charge (33) est pourvue d'évidements (38) dans une région en projection des ouvertures.
PCT/JP2012/062255 2011-05-20 2012-05-14 Élément électroluminescent organique WO2012161005A1 (fr)

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JP2011113515 2011-05-20

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003092191A (ja) * 2001-07-11 2003-03-28 Semiconductor Energy Lab Co Ltd 発光装置及びその作製方法
JP2006331920A (ja) * 2005-05-27 2006-12-07 Fujifilm Holdings Corp 蒸着マスク、有機エレクトロルミネッセンス表示装置、及び、その製造方法
JP2008135259A (ja) * 2006-11-28 2008-06-12 Toppan Printing Co Ltd 有機ｅｌディスプレイパネルおよびその製造方法
JP2008153237A (ja) * 2004-07-22 2008-07-03 Sharp Corp 有機発光素子、及び、それを備えた表示装置
JP2010033936A (ja) * 2008-07-30 2010-02-12 Toshiba Corp 自発光型素子及びその製造方法
JP2010153071A (ja) * 2008-12-24 2010-07-08 Seiko Epson Corp Ｅｌ装置、ｅｌ装置の製造方法

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003092191A (ja) * 2001-07-11 2003-03-28 Semiconductor Energy Lab Co Ltd 発光装置及びその作製方法
JP2008153237A (ja) * 2004-07-22 2008-07-03 Sharp Corp 有機発光素子、及び、それを備えた表示装置
JP2006331920A (ja) * 2005-05-27 2006-12-07 Fujifilm Holdings Corp 蒸着マスク、有機エレクトロルミネッセンス表示装置、及び、その製造方法
JP2008135259A (ja) * 2006-11-28 2008-06-12 Toppan Printing Co Ltd 有機ｅｌディスプレイパネルおよびその製造方法
JP2010033936A (ja) * 2008-07-30 2010-02-12 Toshiba Corp 自発光型素子及びその製造方法
JP2010153071A (ja) * 2008-12-24 2010-07-08 Seiko Epson Corp Ｅｌ装置、ｅｌ装置の製造方法

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