WO2008001756A1

WO2008001756A1 - Organic electroluminescence element

Info

Publication number: WO2008001756A1
Application number: PCT/JP2007/062777
Authority: WO
Inventors: Shinya Tanaka
Original assignee: Sumitomo Chemical Company, Limited
Priority date: 2006-06-28
Filing date: 2007-06-26
Publication date: 2008-01-03
Also published as: TW200808119A

Abstract

An organic electroluminescence element is provided with a first electrode including a transparent electrode or a semi-transparent electrode; a second electrode facing the first electrode; and at least one organic layer arranged between the first electrode and the second electrode. The organic electroluminescence element is composed of a frame-like first auxiliary electrode, which is arranged on the surface of the first electrode and is electrically connected to the first electrode, and a second auxiliary electrode, which is arranged inside the frame of the first auxiliary electrode and is composed of a fine wire electrode electrically connected to the first auxiliary electrode. The first auxiliary electrode and the second auxiliary electrode are composed of a material having a resistivity lower than that of the first electrode.

Description

Specification

Organic electoluminescence device

Technical field

TECHNICAL FIELD [0001] The present invention relates to an organic electoluminescence element useful as a light-emitting element used in a planar light source, a segment display device, a dot matrix display device, a liquid crystal display device and the like. Background art

[0002] In recent years, in display devices and lighting devices, an organic fluorescent dye is used as a light-emitting layer, and this light-emitting layer is laminated with a layer of an organic charge transport compound that has been used for electrophotographic photoreceptors and the like. The use of organic-electric-luminescence elements (hereinafter sometimes referred to as organic EL elements) having a structure has been studied.

[0003] However, in display devices and lighting devices using these organic EL elements, the voltage drop due to the wiring resistance of the transparent electrode or translucent electrode cannot be ignored as the light emitting area increases. There is a problem that the unevenness of the light emission luminance is increased.

[0004] In order to solve such a problem, for example, in Japanese Unexamined Patent Application Publication No. 2004-14128 (Patent Document 1), in a planar light emitting device using an organic EL element, a transparent electrode of the organic EL element is disclosed. In addition, a planar light emitting device is disclosed in which an auxiliary electrode having a resistance lower than that of the transparent electrode is electrically connected. In addition, in the specification of Patent Document 1, the auxiliary electrode is thinned in a portion that is thick and far from the connection terminal, so that the current value is high and the light emission is strong in the portion near the connection terminal, but the aperture ratio is high. It is described that in a small and far part, the current value is small and the light emission is weak and the aperture ratio is large, so that unevenness of the light emission brightness as a whole can be suppressed.

However, even when an organic EL element as described in Patent Document 1 is used, the current value becomes small at a portion far from the connection terminal, so that unevenness in emission luminance is sufficiently suppressed. I couldn't control it. In addition, there is a problem in that the light use efficiency is lowered when unevenness of light emission luminance is suppressed while adjusting the aperture ratio.

Patent Document 1: Japanese Patent Laid-Open No. 2004-14128

Disclosure of the invention Problems to be solved by the invention

[0006] The present invention has been made in view of the above-described problems of the prior art, reduces voltage drop due to resistance of a transparent electrode or a semi-transparent electrode, and causes uneven light emission brightness even when the light emission area is large. An object of the present invention is to provide an organic electoluminescence device that is sufficiently suppressed and capable of uniform light emission.

Means for solving the problem

[0007] As a result of intensive studies to achieve the above object, the present inventor has found that a first electrode including a transparent electrode or a semitransparent electrode, a second electrode facing the first electrode, and the first electrode In an organic electret nominence element comprising an electrode and at least one organic layer provided between the second electrode, the auxiliary electrode is arranged in a specific form on the surface of the first electrode, thereby making it transparent The inventors have found that the voltage drop due to the resistance of the electrode or the translucent electrode can be reduced, and that unevenness in light emission luminance can be sufficiently suppressed even when the light emission area is large, and the present invention has been completed.

[0008] That is, the organic electoluminescence device of the present invention includes a first electrode including a transparent electrode or a translucent electrode, a second electrode facing the first electrode, the first electrode, and the second electrode. An organic electroluminescence device comprising at least one organic layer provided between electrodes,

A frame-shaped first auxiliary electrode disposed on the surface of the first electrode and electrically connected to the first electrode;

A second auxiliary electrode which is arranged in a frame of the first auxiliary electrode and is constituted by a thin wire electrode electrically connected to the first auxiliary electrode;

The first auxiliary electrode and the second auxiliary electrode are made of a material having a lower resistivity than that of the first electrode.

[0009] Further, in the organic electoluminescence device of the present invention, the ratio of the line width of the second auxiliary electrode to the first auxiliary electrode (the line width of the second auxiliary electrode / the line of the first auxiliary electrode) The width) force is preferably in the range of 1/1000 to 1/10.

[0010] Further, in the organic electoluminescence device of the present invention, the first auxiliary electrode and the second auxiliary electrode are surfaces of the surface of the first electrode opposite to the organic layer. Les, which are preferably placed on the surface.

[0011] Further, in the organic electoluminescence device of the present invention, the first electrode is partitioned into a plurality of electrically separated cells, and each of the plurality of cells is electrically connected by the second auxiliary electrode. Are preferably connected.

[0012] A planar light source of the present invention is characterized by including the organic electoluminescence device. In addition, a segment display device of the present invention is characterized by including the organic-elect mouth luminescence element. Furthermore, the dot matrix display device of the present invention is characterized by comprising the organic electoluminescence device. In addition, a liquid crystal display device of the present invention includes the organic electoluminescence device.

[0013] Note that, according to the organic electoluminescence device of the present invention, the voltage drop due to the resistance of the transparent electrode or the translucent electrode is reduced, and even when the emission area is wide, unevenness in the emission luminance is sufficiently suppressed, Uniform light emission is possible. That is, in the organic electoluminescence device of the present invention, the frame-shaped first auxiliary electrode electrically connected to the first electrode on the surface of the first electrode including the transparent electrode or the translucent electrode, And a second auxiliary electrode which is arranged in a frame of the first auxiliary electrode and is constituted by a thin wire electrode electrically connected to the first auxiliary electrode. The first auxiliary electrode and the second auxiliary electrode are made of a material having a low resistivity (high electrical conductivity) compared to the first electrode, and therefore, a voltage drop due to the resistance of the first electrode. Can be reduced.

Furthermore, in the present invention, the first auxiliary electrode has a wide line width and can pass a sufficient current. Therefore, even if the distance from the connection terminal is long, the first auxiliary electrode is affected by a voltage drop due to wiring resistance. Hardly receive. In addition, although the second auxiliary electrode is affected by the voltage drop due to the wiring resistance due to its thin line width, it uses light that blocks the amount of light generated by the organic layer force due to its thin line width. The effect on efficiency is small. In the present invention, since the second auxiliary electrode is disposed within the frame of the first auxiliary electrode and is electrically connected, even if the distance from the connection terminal is long. Voltage drop due to wiring resistance is alleviated. Therefore, according to the organic electoluminescence device of the present invention, the voltage drop due to the resistance of the transparent electrode or the translucent electrode is reduced, and the light emitting area is widened. Even in such a case, unevenness in light emission luminance is sufficiently suppressed, and uniform light emission is possible.

[0015] In the present invention, the first electrode is partitioned into a plurality of electrically separated cells, and the plurality of cells are electrically connected to each other by the second auxiliary electrode. By doing so, the emission luminance can be further improved. That is, by dividing the first electrode into a plurality of electrically separated cells, it is possible to suppress the light emitting component that is guided in the surface direction of the first electrode, and to improve the light emission luminance. Become. In addition, since the plurality of cells are electrically connected to each other by the second auxiliary electrode, unevenness in light emission luminance between the plurality of cells is sufficiently suppressed.

The invention's effect

[0016] According to the present invention, an organic electoluminescence device capable of reducing the voltage drop due to the resistance of the transparent electrode or the translucent electrode, sufficiently suppressing unevenness in light emission luminance even when the light emission area is large, and capable of uniform light emission. Can be provided.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the organic electoluminescence device of the present invention will be described in detail according to preferred embodiments thereof.

[0018] The organic electoluminescence device of the present invention includes a first electrode including a transparent electrode or a translucent electrode, a second electrode facing the first electrode, and between the first electrode and the second electrode. An organic electoluminescence device comprising at least one organic layer provided,

It is characterized by providing.

[0019] (First electrode)

The 1st electrode concerning this invention is an electrode containing a transparent electrode or a semi-transparent electrode, Comprising: It becomes an anode of the organic electoluminescence element of this invention. As such a first electrode, use a metal oxide, metal sulfide or metal thin film with high electrical conductivity. Those having a high transmittance can be suitably used, and can be appropriately selected depending on the organic layer to be used. Examples of the material for the first electrode include indium oxide, zinc oxide, tin oxide, and conductive glass composed of indium 'tin' oxide (ITO), indium 'zinc oxide, etc., which are composites thereof. (NESA, etc.), gold, platinum, silver and copper are used. Among these, ITO, indium / zinc oxide and tin oxide are preferable.

[0020] The film thickness of the first electrode as described above is a force that can be appropriately selected in consideration of light transmittance and electrical conductivity, for example, 10 nm to 10 xm, preferably 20 nm to l μm. Yes, more preferably from 50 nm to 500 nm.

[0021] Further, when the first electrode is divided into a plurality of electrically separated cells, the distance between adjacent cells is lm to 50 μ50η, preferably Five ! ~ 30 z m. If the distance between the P-contact cells is less than the lower limit, the light guided in the surface direction of the first electrode tends not to be sufficiently suppressed. On the other hand, if the upper limit is exceeded, the actual light emitting area is not increased. Since it becomes smaller, the luminous efficiency tends to decrease.

Further, the shape of the plurality of cells electrically separated in this way is not particularly limited, and examples thereof include a rectangular shape such as a stripe shape, a triangular shape, and a quadrangular shape. In the case where such a first electrode is divided into a plurality of electrically separated cells, the first electrode is formed when the organic electroluminescence device of the present invention is produced. After that, the material of what is formed (for example, auxiliary electrode, organic layer) is filled between the adjacent cells.

[0023] Examples of the method for forming the first electrode as described above include a vacuum deposition method, a sputtering method, an ion plating method, and a plating method. Examples of a method of partitioning such a first electrode into a plurality of electrically separated cells include a method of forming a pattern by an etching method using a photoresist after forming the first electrode. The

[0024] Note that, as such a first electrode, a transparent conductive film made of an organic material such as polyaniline or a derivative thereof, polythiophene or a derivative thereof may be used. In addition, from the viewpoint of facilitating charge injection into the organic layer, a conductive polymer such as a phthalocyanine derivative or a polythiophene derivative, Mo oxide, amorphous force is formed on the surface of the first electrode on the organic layer side. A layer with a thickness of 1 to 200 nm such as monobon, carbon fluoride, polyamine compound, etc., or a layer with an average film thickness of 10 nm or less made of metal oxide, metal fluoride, organic insulating material, etc. may be provided.

[0025] (auxiliary electrode)

In the organic electoluminescence device of the present invention, a frame-shaped first auxiliary electrode disposed on the surface of the first electrode and electrically connected to the first electrode;

A second auxiliary electrode disposed within the frame of the first auxiliary electrode and configured by a thin wire electrode electrically connected to the first auxiliary electrode;

It is necessary to have In the present invention, by arranging the first auxiliary electrode and the second auxiliary electrode on the surface of the first electrode in the form as described above, even when the light emitting area of the organic EL element is large, unevenness in light emission luminance is achieved. It can be sufficiently suppressed.

Examples of the arrangement form of the first auxiliary electrode and the second auxiliary electrode include the arrangement forms shown in FIG. 1, FIG. 2, FIG. 3, and FIG. In the arrangement form shown in FIG. 1, the second auxiliary electrodes made up of thin wire electrodes are arranged in a lattice pattern within the frame of the frame-shaped first auxiliary electrode. Further, in the arrangement form shown in FIG. 2, the second auxiliary electrodes made of thin wire electrodes are arranged in a stripe pattern in the frame of the frame-shaped first auxiliary electrode. Furthermore, in the arrangement form shown in FIG. 3, the second auxiliary electrode constituted by the thin wire electrode is arranged in a honeycomb shape within the frame of the frame-shaped first auxiliary electrode. In the arrangement form shown in FIG. 4, the second auxiliary electrodes made up of fine wire electrodes are arranged in a lattice shape within the frame of the frame-like first auxiliary electrode, and further, the fine auxiliary wires are made up of fine wire electrodes in the lattice. The second auxiliary electrodes are arranged in a grid pattern.

[0027] Here, the shape of the frame-shaped first auxiliary electrode is not particularly limited as long as the second auxiliary electrode is formed in the frame, and examples thereof include a rectangular shape and a circular shape. In addition, the line width of the first auxiliary electrode can be appropriately selected according to the light emitting area of the organic-electric-luminescence element, but is preferably in the range of 3 to 20 mm. It is more preferable. Further, the line width of the thin wire electrode constituting the second auxiliary electrode (hereinafter referred to as “the line width of the second auxiliary electrode”) is in the range of:! To 200 xm from the viewpoint of light utilization efficiency. The range of 10 to 100 μm is more preferable. In the present invention, the ratio of the line widths of the second auxiliary electrode and the first auxiliary electrode (the line width of the second auxiliary electrode / the line width of the first auxiliary electrode) is 1 / 1000 to: 1/10 is preferable. 1/500 to 1/20 is more preferable. If the ratio of the line widths is within the above range, the light use efficiency tends to be further improved, and unevenness in the light emission luminance can be further suppressed.

[0029] As a material for the first auxiliary electrode and the second auxiliary electrode, (the higher the electrical conductivity) the first Invite than resistivity lower electrode material is not particularly limited, usually 10 ⁷ A conductive material having an electrical conductivity of S / cm or more is used, and metal materials such as aluminum, silver, chromium, gold, copper, and tantalum are preferably used. Among these, aluminum, chromium, copper, and silver are more preferable from the viewpoint of high electrical conductivity and ease of material handling.

[0030] Further, when a metal is used as the material of the first auxiliary electrode and the second auxiliary electrode, light from the organic layer described later is blocked, so that the auxiliary electrode covers the light emitting area of the element. The area ratio is preferably 20% or more and 90% or less, more preferably 30% or more and 80% or less.

[0031] Further, the thicknesses of the first auxiliary electrode and the second auxiliary electrode are forces that can be appropriately selected so that the sheet resistance becomes a desired value, for example, 10 to 500 nm, preferably 20 to 300. And more preferably 50 to 150.

[0032] Further, in the organic electoluminescence device of the present invention, the first auxiliary electrode and the second auxiliary electrode may be disposed on the surface of the first electrode on the organic layer side. Although it is good, it is arrange | positioned on the surface on the opposite side to an organic layer from a viewpoint of making electrical connection of said 1st electrode, said 1st auxiliary electrode, and said 2nd auxiliary electrode more reliable. Is preferred.

[0033] As a method of forming the first auxiliary electrode and the second auxiliary electrode as described above, for example, a film of the material of the auxiliary electrode by a vacuum deposition method, a sputtering method, or a laminating method in which a metal thin film is thermocompression bonded. A method of forming a pattern by an etching method using a photoresist after forming the film is mentioned.

[0034] (Second electrode) The 2nd electrode concerning this invention is an electrode arrange | positioned facing said 1st electrode, Comprising: It becomes a cathode of the organic electoluminescence element of this invention. As a material for such a second electrode, a material having a low work function is preferable. , Yttrium, indium, cerium, samarium, europium, terbium, ytterbium, and other metals and alloys of two or more thereof; or one or more of them and gold, silver, platinum, copper, mangan, Alloys with one or more of titanium, cobalt, nickel, tungsten, tin; graphite or graphite intercalation compounds are used. These alloys include magnesium-silver alloy, magnesium-indium alloy, magnesium-aluminum alloy, indium-silver alloy, lithium-aluminum alloy, lithium-magnesium alloy, lithium-indium alloy, calcium-aluminum alloy, etc. It is done.

[0035] The film thickness of such a second electrode can be appropriately selected in consideration of electrical conductivity and durability, but is, for example, 10 nm to 10 μm, preferably 20 nm to l μm. And more preferably 50 nm to 500 nm.

[0036] Examples of the method for forming the second electrode as described above include a vacuum deposition method, a sputtering method, and a laminating method in which a metal thin film is thermocompression bonded. Such a second electrode may have a laminated structure of two or more layers. Further, a layer made of a conductive polymer or a layer made of a metal oxide, metal fluoride, organic insulating material or the like having an average film thickness of 2 nm or less may be provided between the second electrode and the organic layer.

[0037] (Organic layer)

The organic layer according to the present invention is a layer provided between the first electrode and the second electrode.

Such an organic layer may be a layer containing at least one luminescent material, but may be composed of a plurality of layers. The operation of an organic electoluminescence device essentially consists of the process of injecting electrons and holes from the electrode, the process of electrons and holes moving through the organic layer, the recombination of electrons and holes, and singlet excitation. It consists of a process of generating a photon or triplet exciton and a process in which the exciton emits light, but the organic layer is composed of multiple layers In some cases, the functions required in each process can be shared among multiple materials, and each material can be optimized independently. Further, examples of the light emission color of such an organic layer include light emission of an intermediate color and white other than light emission of the three primary colors of red, blue, and green. For full-color elements, light emission of three primary colors is preferable, and for a flat light source, light emission of white or intermediate color is preferable.

[0038] Further, in the present invention, as the light emitting material used in such an organic layer, a polymer light emitting material (ii) that is composed only of the low molecular weight light emitting material (i) can be used. Depending on the type of such luminescent material, the other materials used in the organic layer are different. Therefore, the case of using the low molecular weight luminescent material (i) and the case of using the polymer luminescent material (ii) are described below. Each will be explained separately.

[0039] (i) When using a low molecular weight light emitting material

The organic layer material in the case of using low-molecular-weight luminescent materials is “Organic EL Display” (Co-authored by Shizuo Tokito, Chinamiya Adachi, Hideyuki Murata, Ohm Co., Ltd., 2004, first edition, first edition) Fluorescent and phosphorescent materials, hole transport materials, electron block materials, hole block materials, and electron transport materials described on pages 48, 83 to 99, and 101 to 120 are listed. Specifically, as hole transport materials, JP-A-63-70257, JP-A-63-175860, JP-A-2-135359, JP-A-2-135361, JP-A-2-209988. Described in JP-A-2-311591, JP-A-3-37992, JP-A-3-152184, JP-A-11-35687, JP-A-11-217392, JP-A-2000-80167 Etc. are exemplified.

[0040] Furthermore, examples of the low molecular weight light emitting material (triplet light emitting complex) include Ir (ppy) and Btp Ir (acac) having iridium as a central metal, PtOEP and europium having platinum as a central metal, for example.

3 2

Eu (TTA) phen with a central metal. Specifically, for example, Nature, (

Three

1998), 395, 151, Appl. Phys. Lett. (1999), 75 (1), 4, Pro SPIE— Int. So Opt. Eng. (2001), 4105 (Organic Light— Emitting Materials and Devices IV), 119 , J. Am. Chem. So, (2001), 123, 4304, Appl. Phys. Lett., (1997), 71 (18), 2596, Syn. Met., (1998), 94 (1), 103 , Syn. Met., (1999), 99 (2), 1361, Adv. Mater., (1999), 11 (10), 852, Jpn. J. Ap pi. Phys., 34, 1883 (1995) And the like are exemplified. [0041] The thickness of the layer containing the material of these organic layers is generally a force of 5 to 200 nm that is appropriately selected so that the light emission efficiency and the driving voltage have desired values. The thickness of the hole transport layer is, for example, 10 to:! OOnm, preferably 20 to 80nm. The thickness of the light emitting layer is, for example, 10 to:! OOnm, preferably 20 to 80 nm. The thickness of the hole blocking layer is, for example, 5 to 50 nm, preferably 10 to 30 nm. The thickness of the electron injection layer is, for example, 10 to:! OOnm, preferably 20 to 80 nm.

[0042] As a method for forming these layers, in addition to vacuum processes such as vacuum deposition, cluster deposition, and molecular beam deposition, in the case of a material capable of forming solution emulsion, a coating method or a printing method described later is used. The method of forming a film is mentioned.

[0043] (ii) When using a polymer light-emitting material

Examples of materials for the organic layer in the case of using polymer light-emitting materials include “polymer EL materials” (co-authored by Toshihiro Onishi and Tamami Koyama, published by Kyoritsu Publishing Co., Ltd., 2004, first edition). Thus, an organic electroluminescence device can be constructed with a structure in which the charge injection layer and the charge transport layer are laminated. More specifically, as a hole transport material, an electron transport material, and a light emitting material of a polymer compound, W099 / 13692 published Akira Itada, W099 / 4816 (½ ^? 9 Itoda, GB2340304A, WO00 / 53656 9 Itoda , WO01 / 19834 Kaimei Itoda, WO00 / 55927 Kaimei Itoda, GB2348316, W 000/46321 published specification, WO00 / 06665 published specification, W099 / 54943 published Akira Itada, W099 / 54385 9 Itada, US5777070, WO98 / 06773 ^ J Itoda, WO97 / 05184 Kaimei Itoda, WO00 / 35987 Kaimei Itoda, WO00 / 53655 Open specification, WO01 / 34722 Open specification, W099 / 24526 Open specification, WO00 / 22

Ito, WO00 / 22026A Ito, Ito, US

US Pat. — 123156, JP 2001-3045, JP 2000-351967, JP 2000-303 066, JP 2000-299189, JP 2000-252065, JP 2000 00 — 136379, JP 2000-104057, JP 2000-80167, Polyfluorenes, derivatives and copolymers thereof, polyarylenes, disclosed in JP-A-10-324870, JP-A-10-114891, JP-A-9111233, JP-A-9-45478, etc. Derivatives and copolymers thereof, polyarylene vinylenes, derivatives and copolymers thereof, and (co) polymers of aromatic amines and derivatives thereof. These polymer light-emitting materials and charge transport materials can be mixed with light-emitting materials and charge transport materials used in the organic layer when the above-described low-molecular light-emitting materials are used. . In these polymer light emitting materials and charge transport materials, the low molecular light emitting materials described above may be included in the structure of these materials.

[0044] As a specific example of the charge injection layer, a layer containing a conductive polymer or provided between the first electrode and the hole transport layer, the material of the first electrode and the hole transport layer are provided. A layer including a material having an ionic potential of an intermediate value with respect to the included hole transporting material, provided between the second electrode and the electron transport layer, and included in the material of the second electrode and the electron transport layer A layer containing a material having an electron affinity with a value intermediate to that of the electron transporting material.

[0045] When such a charge injection layer is a layer containing a conductive polymer, the layer containing the conductive polymer is located between at least one electrode (first electrode, second electrode) and the light emitting layer. Next to the electrode.

In order to reduce the leakage current between the light emitting pixels, the electrical conductivity of such a conductive polymer is preferably 10 ^_7 S / cm or more and preferably 10 ³ S / cm or less. it is particularly preferred that the ¾ / cm or more at and and equal to or less than 10 ² S / cm is less than more preferably tool is at 10_ ⁵ S / cm or more and lo / cm. Further, usually such conductive the electric conductivity of the high-molecular to less 10_ ⁵ S / cm or more at and and 10 ³ S / cm, a suitable amount of ions are doped into the good Una conductive polymer.

[0046] As ions to be doped, an anion is used for the hole injection layer, and a force thione is used for the electron injection layer. Examples of anions include polystyrene sulfonate ions, alkylbenzene sulfonate ions, camphor sulfonate ions, etc., and examples of cations include lithium ions, sodium ions, potassium ions, tetraptyl ammonium ions. Etc. [0047] The material used for the charge injection layer may be appropriately selected depending on the material of the electrode and the adjacent layer, but polyaniline and derivatives thereof, polythiophene and derivatives thereof, polypyrrole and derivatives thereof, polyphenylene. Lembinylene and its derivatives, Polyethylene vinylene and its derivatives, Polyquinoline and its derivatives, Polyquinoxaline and its derivatives, Conductive polymers such as polymers containing an aromatic amine structure in the main chain or side chain; Metal phthalocyanine (copper Phthalocyanine, etc.); carbon and the like.

[0048] For the purpose of facilitating charge injection, an insulating layer having a thickness of 10 nm or less may be provided adjacent to the first electrode and / or the second electrode. Examples of such an insulating layer material include metal fluorides, metal oxides, organic insulating materials, and the like, and metal fluorides and metal oxides such as alkali metals and alkali earth metals are preferable.

[0049] The electron transporting polymer material contained in the organic layer on the side close to the second electrode is not particularly limited as long as it is a polymer material that injects electrons from the electrode and transports electrons. However, a π and σ conjugated polymer or a polymer material containing an electron transporting group in the polymer can be used as appropriate. Furthermore, a low molecular electron transporting material can be used in combination.

[0050] In addition to charge transport, these hole transporting materials and electron transporting materials can also be suitably used for those having a light emitting mechanism. In the present invention, these layers are doped with the light emitting material. It can also be used.

[0051] The thickness of the layer containing the material of the organic layer as described above has an optimum value depending on the material used, but can be appropriately selected so that the driving voltage and the light emission efficiency become appropriate values. . The thickness of the light emitting layer is, for example, 5 to 300 nm, preferably 30 to 200 nm, and more preferably 40 to 150 nm. The thickness of the charge injection layer is, for example, 1 nm to 1000 nm, preferably 2 nm to:! OOnm. The thickness of the electron transport layer is, for example, 1 nm to l z m, preferably 2 nm to 500 nm, more preferably 5 nm to 200 nm.

[0052] In addition, as a method for forming a layer (light emitting layer, charge transport layer, charge injection layer) containing a polymer material among the organic layer materials described so far, for example, coating from a solution is used. And a method of forming a film by a printing method or a printing method. In addition, such a method is It can also be used as a method for forming a layer that does not contain a child material (light emitting layer, charge transport layer, charge injection layer). According to such a method, it is only necessary to remove the solvent by drying after applying the solution, and the same method can be applied even when a charge transport material or a light emitting material is mixed, which is very advantageous in production. is there. Examples of such coating and printing methods include spin coating, casting, micro gravure coating, gravure coating, bar coating, roll coating, wire bar coating, dip coating, spray coating, and screen. Examples of the coating method include a printing method, a flexographic printing method, an offset printing method, a slippery coating method, a nozure coating method, and an inkjet printing method. Further, the charge injection material can be formed into an emulsion in which water or alcohol is dispersed in the same manner as the solution.

In such a coating method or printing method, the solvent used for the material of the organic layer is not particularly limited, but a solvent capable of dissolving or uniformly dispersing the polymer material is preferable. In the case where the polymer material is soluble in a non-polar solvent, examples of such solvents include chlorine solvents such as chloroform, methylene chloride, dichloroethane; ether solvents such as tetrahydrofuran; toluene , Xylene, tetralin, anisole, n-hexylbenzene, cyclohexylbenzene and other aromatic hydrocarbon solvents; decalin, bicyclohexyl and other aliphatic hydrocarbon solvents; acetone, methyl ethyl ketone, 2- Examples include ketone solvents such as heptanone; ester solvents such as ethyl acetate, butyl acetate, ethyl cellosolve acetate, and polypropylene alcohol monomethyl ether acetate.

[0054] When a plurality of layers are stacked, it is preferable to insolubilize the first formed layer in order to prevent mixing of the upper and lower layers. As a method for insolubilization in this way, a soluble precursor or a polymer having a soluble group is used, and the precursor is converted into a synergistic polymer by heat treatment or dissolved by decomposing the soluble group. A method of insolubilizing by lowering the property, a method of using a hole transporting polymer having a crosslinking group in the molecule, a method of mixing a monomer or a macromer that causes a crosslinking reaction by heat, light, electron beam, etc. Are listed.

[0055] Examples of such a cross-linking group include polymers having a bur group, a (meth) acrylate group, an oxetane group, a cyclobutadiene group, a gen group and the like in the side chain. The introduction rate of these groups is There is no particular limitation as long as it is insolubilized in the solvent used for film formation of the electron transporting polymer, but for example 0.01 to 30% by mass, preferably 0.5 to 20% by mass, and more preferably rather is:! it is ~ 10 mass ^_0/0.

[0056] The monomer or macromer that causes a crosslinking reaction is a compound having a weight average molecular weight of 2000 or less in terms of polystyrene, such as a bur group, a (meth) acrylate group, an oxetane group, a cyclobutadiene group, and a gen group. Those having two or more groups are exemplified. Furthermore, compounds that can undergo a cross-linking reaction between molecules such as acid anhydride groups and cinnamic acid are also exemplified. As examples of these, those described in “Current Status and Prospects of UV'EB Curing Technology” (supervised by Kunihiro Kashimura, CMC Publishing 2002, 1st edition, 1st edition, 2nd chapter) are preferably used. it can.

[0057] Furthermore, when a polymer compound is used as the material for the organic layer, the purity affects the device performance such as charge transport characteristics and light emission characteristics. Therefore, the monomer before polymerization is distilled, sublimated and purified, Polymerization is preferably performed after purification by a column chromatography method such as recrystallization. In addition, after polymerization, acid washing, alkali washing, neutralization, water washing, organic solvent washing, reprecipitation, centrifugation, extraction, column chromatography, dialysis, and other conventional separation operations, purification operations, drying, and other operations It is preferable to carry out a purification treatment by the above.

[0058] (Organic Elect Mouth Luminescence Element)

The organic electoluminescence device of the present invention can be produced by forming the first electrode, the second electrode, the first auxiliary electrode, the second auxiliary electrode, and the organic layer on the support substrate. As such a support substrate, any substrate that does not change when producing an organic electoluminescence device may be used. Examples thereof include glass, plastic, polymer film, and silicon substrate. In addition, when taking out the light from the said organic layer from such a support substrate side, it is preferable to use a transparent thing as a support substrate. The element structure of the organic electoluminescence device of the present invention is not particularly limited, and it may be a top emission type or a bottom emission type. Further, it is possible to appropriately select the order in which the first electrode and the like are formed on the support substrate according to such an element structure. Furthermore, in the organic electoluminescence device of the present invention, a protective layer may be provided as necessary. Examples of the material for such a protective layer include glass, plastic, polymer film, silicon substrate, and photo-curing resin such as acrylic resin. . These protective layer materials can be used singly or in combination of two or more. In addition, when taking out the light from the said organic layer from such a protective layer side, it is preferable to use a transparent thing as a material of a protective layer.

[0059] The organic-electric-luminescence element of the present invention as described above is a curved or flat surface light source for a backlight or illumination of a liquid crystal display; a segment display device used for interiors and advertisements It can be suitably used as a light-emitting element used in dot matrix display devices, liquid crystal display devices, and the like.

Example

[0060] Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples, but the present invention is not limited to the following Examples. The compounds A to C represented by the following structural formulas (A) to (C) used in Synthesis Examples 1 and 2 were synthesized according to the method described in the published specification of WO2000 / 046321. .

[0061] [Chemical 1]

[0062] [Chemical 2]

[0063] [Chemical 3]

[0064] (Synthesis Example 1)

Polymer compound 1 represented by the following general formula (1) was synthesized by the following method.

[0065] [Chemical 4]

[0066] That is, first, in a 200 ml separable flask, 0.991 g of methyltrioctyl ammonium chloride (trade name: Aliquat336, manufactured by Anoledritch Co., Ltd.) and 5.23 g of Compound A were combined. After charging 4.55 g of product C into the reaction vessel, the inside of the reaction system was replaced with nitrogen gas. Thereafter, 70 ml of toluene was added, and 2. Omg of palladium acetate and 15.1 mg of tris (o_tolyl) phosphine were added, followed by refluxing to obtain a mixed solution.

[0067] Next, 19 ml of an aqueous sodium carbonate solution was added dropwise to the obtained mixed solution, and the mixture was stirred overnight under reflux, and then 0.12 g of phenylboric acid was added and stirred for 7 hours. Thereafter, 300 ml of toluene was added, the reaction solution was separated, and the organic phase was washed with an acetic acid aqueous solution and water, and then an aqueous solution of sodium N, N decyldithiocarbamate was added and stirred for 4 hours.

[0068] Next, after the mixed solution after stirring was separated, the solution was passed through a silica gel alumina column, washed with toluene, and then dropped into methanol to precipitate a polymer. Then, the obtained polymer was filtered, After drying under reduced pressure, it was dissolved in toluene. The obtained toluene solution is dropped again into methanol to form a precipitate, which is filtered and dried under reduced pressure. 6.33 g of polymer compound 1 was obtained. The polystyrene equivalent weight average molecular weight Mw of the obtained polymer compound 1 was 3.2 X 10 ⁵ , and the polystyrene equivalent number average molecular weight Mn was 8.8 X

10 was ⁴ .

[0069] (Synthesis Example 2)

Polymer compound 2 represented by the following general formula (2) was synthesized by the following method.

[0070] [Chemical 5]

That is, first, 22.5 g of compound B and 17.6 g of 2,2 ′ bibilidyl were charged into a reaction vessel, and then the inside of the reaction system was replaced with nitrogen gas. Thereafter, 1500 g of tetrahydrofuran (dehydrated solvent) deaerated by bubbling with argon gas in advance was collected to obtain a mixed solution. Then, 31 g of bis (1,5 cyclooctagen) nickel (0) was added to the obtained mixed solution, stirred at room temperature for 10 minutes, and reacted at 60 ° C. for 3 hours. The reaction was performed in a nitrogen gas atmosphere.

[0072] Next, after cooling the obtained reaction solution, a mixed solution of 25 mass% ammonia water 200m 1Z methanol 900ml / ion-exchanged water 900ml was poured into this solution and stirred for about 1 hour. Thereafter, the produced precipitate was collected by filtration, and this precipitate was dried under reduced pressure and then dissolved in toluene. Then, the obtained toluene solution was filtered to remove insoluble matters, and then this tonorene solution was purified by passing through a column packed with alumina.

[0073] Next, the purified toluene solution was washed with a 1N aqueous hydrochloric acid solution, allowed to stand and separated, and then the toluene solution was recovered. Then, this tonorene solution was washed with about 3% by mass ammonia water, allowed to stand and liquid separation, and then the toluene solution was recovered. Thereafter, this toluene solution was washed with ion-exchanged water, allowed to stand and separated, and the washed toluene solution was recovered.

[0074] Next, the washed tonorene solution was poured into methanol to form a precipitate. The precipitate was washed with methanol and then dried under reduced pressure to obtain polymer compound 2. The obtained polymer compound 2 had a polystyrene equivalent weight average molecular weight of 8.2 × 10 ⁵ , The number-average molecular weight in terms of len was 1. OX 10 ⁵ .

[0075] (Example 1)

A glass substrate (100 mm x 100 mm) is used as the support substrate, Cr is used on the support substrate and Ar is used as the sputtering gas. Deposited. The film forming pressure at this time was 0.5 Pa, and the sputtering power was 2. OkW. After applying the resist on the Cr film, 1 beta for 90 seconds at 10 ° C, then a square frame-shaped opening composed of a line width of 20 mm and a vertical-horizontal pitch in the frame of the opening. 300 μ m. 100 μ m, respectively, through a photomask having an open mouth of the lattice consisting of the line width 70 μ ηι · 30 μ m, and the exposure energy of 200 mJ, hydroxide of 0.5 mass ^_0/0 After development with an aqueous potassium solution, it was post-beta for 10 seconds at 130 ° C. Next, immerse in Cr etching solution at 40 ° C for 120 seconds, pattern Cr, and finally immerse in 2% by weight aqueous potassium hydroxide solution to remove resist residue and consist of Cr Auxiliary electrodes (first auxiliary electrode and second auxiliary electrode) were formed.

Next, the first electrode was formed on the substrate on which the auxiliary electrode was formed. In other words, ITO having a film thickness of 3000 nm was deposited by a DC sputtering method at 120 ° C. using an ITO firing target as the first electrode material and Ar as the sputtering gas. At this time, the film forming pressure was 0.25 Pa, and the sputtering power was 0.25 kW. Then, annealing was performed in an oven at 200 ° C for 40 minutes. After that, the substrate on which the first electrode is formed is ultrasonically cleaned using a weak alkaline detergent at 60 ° C, cold water, and hot water at 50 ° C, pulled up from the hot water at 50 ° C and dried, and then UV-treated for 20 minutes. / ○ washed.

Three

[0077] Then, a suspension of poly (3,4) ethylenedioxythiophene / polystyrene sulfonic acid (trade name: BaytronP CH8000, manufactured by Starck Vitec Co., Ltd.) was added to the cleaned substrate. Using the solution filtered at the second stage using a m-diameter filter and a 0.2 μm-diameter filter, a thin film is formed with a thickness of 80 nm by spin coating, and 200 ° on an air atmosphere on a hot plate. A hole injection layer was formed by heat treatment with C for 15 minutes. Next, the polymer compound 1 and the polymer compound 2 obtained in Synthesis Examples 1 and 2 were weighed at a weight ratio of 1: 1, and dissolved in toluene to prepare a 1% by mass polymer solution. A polymer solution is spin-coated on a substrate on which a hole injection layer is formed to form a film with a thickness of 80 nm, and then a nitrogen atmosphere. A light emitting layer was formed by heat treatment at 130 ° C. for 60 minutes on the lower hot plate. Thereafter, the substrate on which the light emitting layer was formed was introduced into a vacuum vapor deposition machine, and LiF, Ca, and A1 were sequentially deposited as cathodes at thicknesses of 2 nm, 5 nm, and 200 nm, respectively, to form a second electrode. Degree of vacuum metal vapor deposition was initiated after reaching below 1 X 10- ⁴ Pa. Finally, the surface of the second electrode on the substrate on which the second electrode is formed is covered with a glass plate in an inert gas, and the four sides are further covered with a photocurable resin, and then the photocurable resin is cured. An organic EL light-emitting device was fabricated by forming a protective layer.

The organic EL light emitting device thus obtained is shown in FIG. That is, the organic EL device shown in FIG. 5 includes a support substrate 1, a first auxiliary electrode 2, a second auxiliary electrode 3, a first electrode 4, a charge injection layer 5, a light emitting layer 6, a second electrode 7, and a protective layer 8. It has. An organic layer 11 consisting of the charge injection layer 5 and the light emitting layer 6 is sandwiched between the first electrode 4 and the second electrode 7. The first auxiliary electrode 2 and the second auxiliary electrode 3 are disposed on the surface of the first electrode 4 opposite to the organic layer 11.

[0079] (Comparative Example 1)

As a photomask for forming the auxiliary electrode, a comparative organic EL was used in the same manner as in Example 1 except that a photomask having only a square frame-shaped opening composed of a line width of 20 mm was used. A light emitting element was manufactured.

[0080] (Comparative Example 2)

As a photomask for forming the auxiliary electrode, the vertical and horizontal pitches are 300 μm each 1

A comparative organic EL light-emitting device was fabricated in the same manner as in Example 1 except that a photomask having a lattice-type opening made of 00 μm and a line width of 70 μΐη · 30 βm was used.

[0081] <Evaluation of light emission characteristics of organic EL light emitting device>

The light emission characteristics of the organic EL light emitting devices obtained in Example 1 and Comparative Examples 1 and 2 were evaluated. In other words, the luminance of light emitted when a voltage of 8 V was applied to the entire device was measured, and the appearance of the light emitting surface was visually observed. The results obtained are shown in Table 1.

[0082] [Table 1] table 1

As is clear from the results shown in Table 1, in the organic electoluminescence device of the present invention, even when the emission area is large, unevenness in emission luminance is sufficiently suppressed, and uniform emission is possible. Was confirmed.

Industrial applicability

As described above, according to the present invention, the voltage drop due to the resistance of the transparent electrode or the translucent electrode is reduced, and even when the light emitting area is large, unevenness in the light emission luminance is sufficiently suppressed, and uniform light emission is achieved. It is possible to provide an organic-electric-mouth luminescence element that can be used.

Therefore, the organic electoluminescence element of the present invention is useful as a light emitting element used in a planar light source, a segment display device, a dot matrix display device, a liquid crystal display device and the like.

Brief Description of Drawings

[0086] [FIG. 1] A schematic plan view showing the positional relationship between a first auxiliary electrode and a second auxiliary electrode arranged on the surface of the first electrode in a preferred embodiment of the organic electroluminescence device of the present invention. It is.

FIG. 2 is a schematic plan view showing the positional relationship between a first auxiliary electrode and a second auxiliary electrode arranged on the surface of the first electrode in another preferred embodiment of the organic electoluminescence device of the present invention.

FIG. 3 is a schematic plan view showing the positional relationship between a first auxiliary electrode and a second auxiliary electrode arranged on the surface of the first electrode in another preferred embodiment of the organic electoluminescence device of the present invention.

FIG. 4 is a schematic plan view showing the positional relationship between the first auxiliary electrode and the second auxiliary electrode arranged on the surface of the first electrode in another preferred embodiment of the organic electoluminescence device of the present invention. FIG. 5 is a schematic cross-sectional view showing the laminated structure of the organic electoluminescence device obtained in the example.

Explanation of symbols

1 Support substrate

2 First auxiliary electrode

3 Second auxiliary electrode

4 First electrode

5 Charge injection layer

6 Light emitting layer

7 Second electrode

8 Protective layer

11 Organic layer

Claims

The scope of the claims

[1] A first electrode including a transparent electrode or a semi-transparent electrode, a second electrode facing the first electrode, and at least one organic layer provided between the first electrode and the second electrode; An organic electoluminescence device comprising:

And the first auxiliary electrode and the second auxiliary electrode are made of a material having a low resistivity as compared with the first electrode, and the organic electoluminescence device.

[2] Ratio of line width between the second auxiliary electrode and the first auxiliary electrode (line width of the second auxiliary electrode / line width of the first auxiliary electrode) 1/1000 to: 1/10 The organic electoluminescence device according to claim 1.

[3] The organic elect mouth according to claim 1 or 2, wherein the first auxiliary electrode and the second auxiliary electrode are arranged on a surface of the first electrode opposite to the organic layer. Nominescence element.

[4] The method according to any one of claims 1 to 3, wherein the first electrode is partitioned into a plurality of electrically separated cells, and the plurality of cells are electrically connected to each other by the second auxiliary electrode. The organic electoluminescence device according to any one of the above.

[5] A planar light source comprising the organic electoluminescence device according to any one of claims 1 to 4.

[6] A segment display device comprising the organic electoluminescence element according to any one of claims 1 to 4.

[7] A dot matrix display device comprising the organic electoluminescence device according to any one of [1] to [4].

[8] A liquid crystal display device comprising the organic electoluminescence device according to any one of claims 1 to 4.