WO2010058690A1 - Élément électroluminescent organique et son procédé de fabrication - Google Patents

Élément électroluminescent organique et son procédé de fabrication Download PDF

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WO2010058690A1
WO2010058690A1 PCT/JP2009/068605 JP2009068605W WO2010058690A1 WO 2010058690 A1 WO2010058690 A1 WO 2010058690A1 JP 2009068605 W JP2009068605 W JP 2009068605W WO 2010058690 A1 WO2010058690 A1 WO 2010058690A1
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alkaline earth
organic
group
alkali metal
earth metal
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PCT/JP2009/068605
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English (en)
Japanese (ja)
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誠之 林
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富士フイルム株式会社
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B33/00—Electroluminescent light sources
    • H05B33/10—Apparatus or processes specially adapted to the manufacture of electroluminescent light sources
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K71/00—Manufacture or treatment specially adapted for the organic devices covered by this subclass
    • H10K71/30—Doping active layers, e.g. electron transporting layers
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/14—Carrier transporting layers
    • H10K50/15—Hole transporting layers
    • H10K50/155—Hole transporting layers comprising dopants
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/14—Carrier transporting layers
    • H10K50/16—Electron transporting layers
    • H10K50/165—Electron transporting layers comprising dopants

Definitions

  • the present invention relates to an organic electroluminescent element (hereinafter sometimes referred to as an organic EL element) that can be effectively used for a surface light source such as a full color display, a backlight, and an illumination light source, and a light source array such as a printer.
  • an organic electroluminescent element hereinafter sometimes referred to as an organic EL element
  • a surface light source such as a full color display, a backlight, and an illumination light source
  • a light source array such as a printer.
  • the organic EL element is composed of a light emitting layer or a plurality of organic layers including a light emitting layer and a counter electrode sandwiching the organic layer.
  • electrons injected from the cathode and holes injected from the anode are recombined in the organic layer, emitted light from the generated excitons, and other molecules generated by energy transfer from the excitons. It is an element for obtaining light emission using at least one of light emission from the excitons.
  • organic EL elements have been developed with greatly improved brightness and element efficiency by using a layered structure with separated functions.
  • a two-layer stacked device in which a hole transport layer and a light-emitting / electron transport layer are stacked
  • a three-layer stacked device in which a hole transport layer, a light-emitting layer, and an electron transport layer are stacked, a hole transport layer, and a light-emitting layer
  • a four-layer stacked element in which a hole blocking layer and an electron transport layer are stacked is often used.
  • an organic EL element having an organic compound layer doped with a metal functioning as a donor (electron donating) dopant at the interface with the cathode is disclosed (for example, see Patent Document 1). According to this configuration, it is said that the energy barrier in electron injection from the cathode to the organic layer is lowered and the driving voltage is reduced.
  • an organic EL element in which a light emitting layer made of an organic compound is formed by vacuum deposition and then heat-treated at 50 ° C. or higher is disclosed (for example, see Patent Document 2).
  • the organic compound as a luminescent material is in an unstable crystalline state at the stage of vacuum deposition, and is subjected to heat treatment at a temperature of 50 ° C. or higher and lower than the melting point of the organic compound. It is said that it changes to an agglomerated structure, thereby efficiently emitting light at a low voltage and emitting light stably for a long period of time.
  • An object of the present invention is to provide an organic electroluminescence device having high luminous efficiency, low driving voltage, and excellent durability, and a method for producing the same.
  • a method for producing an organic electroluminescent device wherein the organic electroluminescent device has at least one organic layer including a light emitting layer between a pair of electrodes, and at least one of the organic layers is An organic layer containing at least one selected from the group consisting of alkali metals, alkali metal salts, alkaline earth metals, and alkaline earth metal salts, the alkali metal, alkali metal salt, alkaline earth metal, And during or after the formation of the organic layer containing at least one selected from the group consisting of alkaline earth metal salts, at least 50 ° C., alkali metal, alkali metal salt, alkaline earth metal, and alkaline earth
  • a method for producing an organic electroluminescent element comprising: performing a heat treatment at a temperature not higher than a melting point of the organic layer containing at least one selected from the group consisting of a metal salt.
  • the heat treatment is performed during film formation of the organic layer containing at least one selected from the group consisting of the alkali metal, alkali metal salt, alkaline earth metal, and alkaline earth metal salt.
  • the heat treatment is performed after forming the organic layer containing at least one selected from the group consisting of the alkali metal, alkali metal salt, alkaline earth metal, and alkaline earth metal salt, ⁇ The manufacturing method of the organic electroluminescent element of 1>.
  • a method for producing an organic electroluminescent device wherein the organic electroluminescent device has at least one organic layer including a light emitting layer between a pair of electrodes, and at least one of the organic layers is at least one layer.
  • An organic layer containing at least one selected from the group consisting of an alkali metal, an alkali metal salt, an alkaline earth metal, and an alkaline earth metal salt, and the alkali metal, alkali metal salt, alkaline earth metal,
  • a method for producing an organic electroluminescent element comprising applying an energization treatment during or after the formation of the organic layer containing at least one selected from the group consisting of alkaline earth metal salts.
  • the energization treatment is performed after forming the organic layer containing at least one selected from the group consisting of the alkali metal, alkali metal salt, alkaline earth metal, and alkaline earth metal salt.
  • ⁇ 6> The method for producing an organic electroluminescent element according to ⁇ 4> or ⁇ 5>, wherein a current density in the energization treatment is 0.1 A / cm 2 or less.
  • At least one selected from the group consisting of the alkali metal, alkali metal salt, alkaline earth metal, and alkaline earth metal salt is at least selected from the group consisting of Li, Na, K, Ca, and Sr
  • the organic layer in the organic layer containing at least one selected from the group consisting of the alkali metal, alkali metal salt, alkaline earth metal, and alkaline earth metal salt The method for producing an organic electroluminescent element according to any one of ⁇ 1> to ⁇ 8>, wherein the content is 0.01% by mass to 10% by mass with respect to the material.
  • the organic layer containing at least one selected from the group consisting of the alkali metal, alkali metal salt, alkaline earth metal, and alkaline earth metal salt contains at least one electron transporting material.
  • ⁇ 11> The method for producing an organic electroluminescent element according to ⁇ 10>, wherein the electron transporting material is an organic material.
  • An organic electroluminescent device having at least one organic layer including a light emitting layer between a pair of electrodes, wherein at least one of the organic layers is an alkali metal, an alkali metal salt, or an alkaline earth metal And an organic layer containing at least one selected from the group consisting of alkaline earth metal salts, and selected from the group consisting of the alkali metals, alkali metal salts, alkaline earth metals, and alkaline earth metal salts The organic layer containing at least one selected from the group consisting of the alkali metal, alkali metal salt, alkaline earth metal, and alkaline earth metal salt at 50 ° C.
  • An organic electroluminescent element which is a layer that has been heat-treated at a temperature lower than the melting point of the layer.
  • An organic electroluminescent element having at least one organic layer including a light emitting layer between a pair of electrodes, wherein at least one of the organic layers is an alkali metal, an alkali metal salt, or an alkaline earth metal And an organic layer containing at least one selected from the group consisting of alkaline earth metal salts, and selected from the group consisting of the alkali metals, alkali metal salts, alkaline earth metals, and alkaline earth metal salts
  • An organic electroluminescent element wherein the organic layer containing at least one selected from the above is a layer subjected to an energization treatment.
  • the organic layer containing at least one selected from the group consisting of the alkali metal, alkali metal salt, alkaline earth metal, and alkaline earth metal salt is an electron transport layer ⁇ 12> or ⁇ 12>13> The organic electroluminescent element as described in 13>.
  • ⁇ 16> Between the electron transport layer and the light emitting layer, ⁇ 14> or ⁇ 14> having a second electron transport layer not containing an alkali metal, an alkali metal salt, an alkaline earth metal, and an alkaline earth metal salt 15>.
  • an organic EL element having high luminous efficiency and low driving voltage and excellent in durability and a method for producing the same are provided.
  • At least one of the organic layers including the light emitting layer is selected from the group consisting of alkali metals, alkaline earth metals, and salts thereof. It is an organic layer containing types, and has a heat treatment step of performing a heat treatment at a temperature of 50 ° C. or higher and a melting point of the organic layer or lower during or after the formation of the organic layer.
  • at least one of the organic layers including the light emitting layer is selected from the group consisting of alkali metals, alkaline earth metals, and salts thereof.
  • the organic material of the layer and the alkali metal, alkaline earth metal, or salt thereof As a result, the carrier density is increased, the electric resistance is decreased, and it is presumed that the driving voltage is decreased, the luminous efficiency is improved, and the driving durability is improved.
  • This effect is completely different from the formation of the microcrystalline aggregate structure of the luminescent material disclosed in JP-A-5-18264.
  • the effect of the present invention is particularly great when the organic layer containing the alkali metal, alkaline earth metal, or salt thereof is an electron transport layer. Furthermore, a particularly great effect is obtained when the electron transport material of the electron transport layer is a phenanthroline derivative.
  • the organic electroluminescent element of the present invention will be described in detail.
  • the organic layers are laminated in the order of the light emitting layer and the electron transport layer from the anode side.
  • a hole injection layer may be provided between the anode and the light emitting layer
  • a hole transport layer may be provided between the hole injection layer and the light emitting layer
  • an electron injection layer may be provided between the electron transport layer and the cathode.
  • you may have a charge block layer (an electron block layer, a hole block layer) etc. between the positive hole transport layer and the light emitting layer, or between the light emitting layer and the electron transport layer.
  • the organic layer containing at least one selected from the group consisting of alkali metals, alkaline earth metals, and salts thereof is an electron transport layer. More preferably, a second electron transport layer that does not contain any of an alkali metal, an alkaline earth metal, or a salt thereof is disposed between the electron transport layer and the light emitting layer.
  • the configuration of the organic layer in the organic electroluminescent element of the present invention is preferably an embodiment having at least a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer in order from the anode side. . More preferably, in order from the anode side, at least a hole injection layer, a hole transport layer, a light emitting layer, a second electron transport layer, an electron transport layer (sometimes referred to as a first electron transport layer), and an electron injection layer It is the aspect which has.
  • the first electron transport layer is an organic layer containing at least one selected from the group consisting of alkali metals, alkaline earth metals, and salts thereof.
  • FIG. 1 is a schematic cross-sectional view of a preferred embodiment of the layer structure of the organic EL device of the present invention.
  • an anode 2 On the substrate 1, an anode 2, a hole injection layer 3, a hole transport layer 4, a light emitting layer 5, a first electron transport layer 6, an electron injection layer 7, and a cathode 8 are arranged in this order.
  • FIG. 2 is a schematic cross-sectional view of another preferred embodiment of the layer structure of the organic EL device of the present invention.
  • an anode 2 On the substrate 1, an anode 2, a hole injection layer 3, a hole transport layer 4, a light emitting layer 5, a second electron transport layer 9, a first electron transport layer 6, an electron injection layer 7, and a cathode 8 are sequentially formed. Be placed.
  • Each layer may be divided into a plurality of secondary layers.
  • each layer constituting the organic layer is preferably formed by any of dry film forming methods such as vapor deposition and sputtering, transfer methods, printing methods, coating methods, ink jet methods, and spray methods. Can be formed.
  • the step of forming the organic layer in the present invention includes at least 50 ° C. during or after the formation of the organic layer containing at least one selected from the group consisting of alkali metals, alkaline earth metals, and salts thereof. It has the heat processing process which heat-processes at the temperature below melting
  • the step of performing the heat treatment is a step of forming the organic layer, and may be continuously performed from the initial stage of the film formation until the film formation is completed. Or you may heat-process after forming all the organic layers.
  • the step of applying the energization treatment is preferably performed after all the organic layers and electrodes are formed.
  • the heating means used in the heat treatment step in the present invention is not particularly limited as long as it heats the organic layer at a desired temperature, and generally known heating means can be used. Specific examples include, for example, a method in which a drum-like or flat plate-like heat medium is brought into contact with the substrate, the substrate is heated, and the organic layer is heated by heat conduction from the substrate, or radiant heat from infrared rays or far infrared rays is used. There are a method of heating indirectly from the surface of the organic layer, a high-frequency heating method, a method of heating by holding in a high-temperature oven, and the like.
  • a substrate heating method is preferable.
  • a heating method using infrared rays, far-infrared rays, or the like, or a method of heating the whole formed element in a high-temperature oven can be preferably used.
  • heating is preferably performed during the formation of an organic layer containing an alkali metal, an alkaline earth metal, or a salt thereof by a substrate heating method.
  • the heat treatment temperature a temperature not lower than 50 ° C. and not higher than the melting point of the organic layer is used. Preferably, it is 60 ° C.
  • the heat treatment time is arbitrary and can be set by finding appropriate conditions depending on the material of the organic layer, but is 1 to 100 hours, more preferably 24 to 72 hours. If the heat treatment time is too long, the performance may begin to deteriorate, and if the heat treatment time is too short, sufficient effects may not be obtained.
  • the energizing process in the present invention includes a method in which the electrode plate is brought into close contact with the energizing surface, and a method in which both electrodes are energized after forming a pair of electrodes of the organic EL element.
  • the electrodes of the organic EL element can be used as they are, and it is preferable to energize the electrodes after forming all the organic layers and electrodes.
  • the energization process of the present invention uses a region different from the current density region for causing the organic EL element to emit light, and the effect of the present invention cannot be obtained by normal energization for light emission.
  • Current density in conduction process in the present invention is preferably from 0.01mA / cm 2 ⁇ 100mA / cm 2, more preferably 0.1mA / cm 2 ⁇ 50mA / cm 2, 0.1mA / cm 2 ⁇ 10mA / Cm 2 is more preferable.
  • the energization process either DC or AC may be used, but in many cases, a sufficient process effect can be obtained with DC in a shorter energization time.
  • the energization time is preferably about 1 to 48 hours. If the energization time is too long, the element may be deteriorated, and if it is too short, a sufficient treatment effect may not be obtained.
  • the organic layer containing at least one selected from the group consisting of alkali metals, alkaline earth metals, and salts thereof in the present invention is preferably an electron transport layer.
  • the electron transport layer is a layer having a function of receiving electrons from the cathode side and transporting them to the anode side, and is disposed between the cathode and the light emitting layer.
  • the electron transport layer in the present invention contains at least one selected from the group consisting of alkali metals, alkaline earth metals, and salts thereof, and an organic electron transport material.
  • Alkali metals, alkaline earth metals, or salts thereof may be used alone or in combination of two or more.
  • an organic electron transport material may be used independently and may use 2 or more types. More preferably, the electron transport layer of the present invention has at least two layers, and contains at least one selected from the group consisting of alkali metals, alkaline earth metals, and salts thereof, and an organic electron transport material.
  • the first electron transport layer has a second electron transport layer that does not contain any of alkali metals, alkaline earth metals, or salts thereof on the light emitting layer side of the first electron transport layer.
  • the total thickness of the electron transport layer is preferably 5 nm to 500 nm, more preferably 10 nm to 200 nm, and still more preferably 15 nm to 100 nm.
  • the thickness of the first electron transport layer is preferably 5 nm to 500 nm, more preferably 5 nm to 200 nm, and still more preferably 10 nm to 100 nm.
  • the thickness of the second electron transport layer is preferably 0.5 nm to 50 nm, more preferably 1 nm to 30 nm, and still more preferably 3 nm to 20 nm.
  • the thickness of the first electron transport layer is preferably larger than the thickness of the second electron transport layer, and the ratio of the thickness of the first electron transport layer / the thickness of the second electron transport layer is preferably 1 to 500, preferably 1.5 to 100 is more preferable, and 2 to 50 is still more preferable.
  • the first electron transport layer is a layer containing at least one kind selected from the group consisting of alkali metals, alkaline earth metals, and salts thereof, and an electron transport material.
  • the content of alkali metal, alkaline earth metal, or salt thereof in the first electron transport layer is 0.01% by mass or more and 10% by mass, and more preferably 0.1% by mass or more and 5% by mass. %, More preferably 0.2% by mass or more and 3% by mass. If the content of alkali metal, alkaline earth metal, or salt thereof is less than 0.01% by mass, a sufficient driving voltage reduction effect cannot be obtained even if heating or energization treatment is performed, which is not preferable. If the content of alkali metal, alkaline earth metal, or a salt thereof exceeds 10% by mass, the efficiency is lowered, which is not preferable.
  • a metal or salt selected from the group consisting of Li, Na, K, Ca, and Sr is preferable. More preferably, it is Li or its salt.
  • the salt refers to a complex compound formed by reaction with a Lewis base, and examples thereof include halides, carbonates, sulfates, nitrates, phosphates, acetates, titanates, and silicates.
  • the mode which dopes these salts formed from alkali metal (alkaline earth metal) in an organic layer, and the simple substance of the alkali metal (alkaline earth metal) doped in the organic layer is organic.
  • An embodiment in which a complex compound is formed by reacting with a compound in the layer is exemplified.
  • an organic electron transport material is preferable. Specifically, a pyridine derivative, a quinoline derivative, a pyrimidine derivative, a pyrazine derivative, a phthalazine derivative, a phenanthroline derivative, a triazine derivative, a triazole derivative, an oxazole derivative.
  • Oxadiazole derivatives imidazole derivatives, fluorenone derivatives, anthraquinodimethane derivatives, anthrone derivatives, diphenylquinone derivatives, thiopyrandioxide derivatives, carbodiimide derivatives, fluorenylidenemethane derivatives, distyrylpyrazine derivatives, naphthalene, perylene, etc.
  • a preferable electron transport material is a phenanthroline derivative.
  • the phenanthroline derivative is preferably a compound represented by the following general formula (ET).
  • R 1 represents a hydrogen atom or a substituent, and n represents an integer of 0 to 8. If n is an integer of 2 or more, plural R 1 may be the same or different.
  • the substituent represented by R 1 is not particularly limited and includes, for example, a halogen atom, an alkyl group (including a cycloalkyl group, a bicycloalkyl group, and a tricycloalkyl group), an alkenyl group (cycloalkenyl group).
  • W represents a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), an alkyl group [a linear, branched, or cyclic substituted or unsubstituted alkyl group.
  • a halogen atom for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom
  • alkyl group [a linear, branched, or cyclic substituted or unsubstituted alkyl group.
  • alkyl groups preferably alkyl groups having 1 to 30 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, t-butyl, n-octyl, eicosyl, 2-chloroethyl, 2-cyanoethyl, 2-ethylhexyl
  • a cycloalkyl group preferably a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, such as cyclohexyl, cyclopentyl, 4-n-dodecylcyclohexyl
  • a bicycloalkyl group preferably having 5 to 30 carbon atoms.
  • a substituted or unsubstituted bicycloalkyl group that is, a monovalent group obtained by removing one hydrogen atom from a bicycloalkane having 5 to 30 carbon atoms, for example, bicyclo [1,2,2] heptan-2-yl, bicyclo [2,2,2] octane-3-yl), a tricyclo structure with more ring structures Domo is intended to cover.
  • An alkyl group (for example, an alkyl group of an alkylthio group) in a substituent described below represents an alkyl group having such a concept, but further includes an alkenyl group and an alkynyl group. ]
  • An alkenyl group [represents a linear, branched or cyclic substituted or unsubstituted alkenyl group. They are alkenyl groups (preferably substituted or unsubstituted alkenyl groups having 2 to 30 carbon atoms, such as vinyl, allyl, prenyl, geranyl, oleyl), cycloalkenyl groups (preferably substituted or substituted groups having 3 to 30 carbon atoms).
  • An unsubstituted cycloalkenyl group that is, a monovalent group obtained by removing one hydrogen atom of a cycloalkene having 3 to 30 carbon atoms (for example, 2-cyclopenten-1-yl, 2-cyclohexen-1-yl), Bicycloalkenyl group (a substituted or unsubstituted bicycloalkenyl group, preferably a substituted or unsubstituted bicycloalkenyl group having 5 to 30 carbon atoms, that is, a monovalent group obtained by removing one hydrogen atom of a bicycloalkene having one double bond.
  • bicyclo [2,2,1] hept-2-en-1-yl, bicyclo 2,2,2] oct-2-en-4-yl An alkynyl group (preferably a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, such as ethynyl, propargyl, trimethylsilylethynyl group), an aryl group (preferably a substituted or unsubstituted aryl having 6 to 30 carbon atoms) Groups such as phenyl, p-tolyl, naphthyl, m-chlorophenyl, o-hexadecanoylaminophenyl), heterocyclic groups (preferably 5- or 6-membered substituted or unsubstituted aromatic or non-aromatic heterocycles A monovalent group obtained by removing one hydrogen atom from a compound, more preferably a 5- or 6-membered aromatic heterocyclic group having 3 to 30 carbon atoms,
  • a heterocyclic oxy group (preferably a substituted or unsubstituted heterocyclic oxy group having 2 to 30 carbon atoms, 1-phenyltetrazol-5-oxy, 2-tetrahydropyranyloxy), an acyloxy group (preferably a formyloxy group, A substituted or unsubstituted alkylcarbonyloxy group having 2 to 30 carbon atoms, a substituted or unsubstituted arylcarbonyloxy group having 6 to 30 carbon atoms, such as formyloxy, acetyloxy, pivaloyloxy, stearoyloxy, benzoyloxy, p- Methoxyphenylcarbonyloxy), a carbamoyloxy group (preferably a substituted or unsubstituted carbamoyloxy group having 1 to 30 carbon atoms, such as N, N-dimethylcarbamoyloxy, N, N-diethylcarbamoyloxy, morpholinocarbony
  • aminocarbonylamino group preferably a substituted or unsubstituted aminocarbonylamino having 1 to 30 carbon atoms, such as carbamoylamino, N, N-dimethylaminocarbonylamino, N, N-diethylaminocarbonylamino, morpholinocarbonylamino
  • Alkoxycarbonylamino group preferably a substituted or unsubstituted alkoxycarbonylamino group having 2 to 30 carbon atoms such as methoxycarbonylamino, ethoxycarbonylamino, t-butoxycarbonylamino, n-octadecyloxycarbonylamino, N-methyl-methoxy Carbonylamino
  • aryloxycarbonylamino group preferably a substituted or unsubstituted aryloxycarbonylamino group having 7 to 30 carbon atoms, such as phenoxycarbonylamino p- chlorophenoxy carbonyl amino
  • Sulfamoylamino group (preferably a substituted or unsubstituted sulfamoylamino group having 0 to 30 carbon atoms, such as sulfamoylamino, N, N-dimethylaminosulfonylamino, Nn-octylaminosulfonylamino ), Alkyl and arylsulfonylamino groups (preferably substituted or unsubstituted alkylsulfonylamino having 1 to 30 carbon atoms, substituted or unsubstituted arylsulfonylamino having 6 to 30 carbon atoms, such as methylsulfonylamino, butylsulfonylamino) , Phenylsulfonylamino, 2,3,5-trichlorophenylsulfonylamino, p-methylphenylsulfonylamino), mercapto group, alkyl
  • Alkyl and arylsulfonyl groups preferably substituted or unsubstituted alkylsulfonyl groups having 1 to 30 carbon atoms, substituted or unsubstituted arylsulfonyl groups having 6 to 30 carbon atoms such as methylsulfonyl, ethylsulfonyl, phenylsulfonyl, p- Methylphenylsulfonyl
  • acyl group preferably formyl group, substituted or unsubstituted alkylcarbonyl group having 2 to 30 carbon atoms, substituted or unsubstituted arylcarbonyl group having 7 to 30 carbon atoms, substitution having 4 to 30 carbon atoms
  • a heterocyclic carbonyl group bonded to a carbonyl group with an unsubstituted carbon atom such as acetyl, pivaloyl, 2-chloroacetyl, stearoyl, be
  • R may be a linking group, for example, a linking group formed of C, N, O, S, Si, or Ge, more preferably a linking group comprising an aromatic ring or an aromatic heterocycle. And particularly preferably a linking group comprising a benzene ring, a pyridine ring, a pyrimidine ring, or a triazine ring.
  • the 2nd electron transport layer in this invention is a layer which does not contain an alkali metal, alkaline-earth metal, or those salts substantially. “Substantially not contained” means that the content of the electron transporting layer is within a range in which no difference is recognized from the case where the electron transporting property of the electron transporting layer does not contain these metals or salts.
  • the second electron transport layer in the present invention preferably contains an organic electron transport material as an electron transport material, and specifically includes a pyridine derivative, a quinoline derivative, a pyrimidine derivative, a pyrazine derivative, a phthalazine derivative, a phenanthroline derivative, and a triazine.
  • Derivatives triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, fluorenone derivatives, anthraquinodimethane derivatives, anthrone derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimide derivatives, fluorenylidenemethane derivatives, distyrylpyrazine Derivatives, aromatic tetracarboxylic anhydrides such as naphthalene and perylene, phthalocyanine derivatives, metal complexes of 8-quinolinol derivatives, metal phthalocyanines, benzoxazoles and benzenes Various metal complexes typified by metal complexes of the thiazole as a ligand, organic silane derivatives typified by silole, and the like. These electron transport materials may be used alone or in combination of two or more.
  • the light emitting layer in the present invention is a layer having a function of receiving holes from the anode, receiving electrons from the cathode, and providing a field for recombination of holes and electrons to emit light when an electric field is applied.
  • the light emitting layer in the present invention preferably contains at least one light emitting material and a host material. Further, the light emitting layer may be a single layer or two or more layers, and each layer may emit light in different emission colors. Even when there are a plurality of light-emitting layers, each layer of the light-emitting layer preferably contains at least one light-emitting material and a plurality of host materials.
  • light emission from triplet excitons can be obtained by combining a fluorescent light emitting material and a host material capable of obtaining light emission (fluorescence) from singlet excitons.
  • a combination of a phosphorescent light emitting material and a host material may be used, and among these, a combination of a phosphorescent light emitting material and a host material is preferable from the viewpoint of light emission efficiency.
  • the light emitting layer in the present invention can contain two or more kinds of light emitting materials in order to improve the color purity and widen the light emission wavelength region.
  • the phosphorescent material include complexes containing a transition metal atom or a lanthanoid atom.
  • the transition metal atom is not particularly limited, but preferably includes ruthenium, rhodium, palladium, tungsten, rhenium, osmium, iridium, and platinum, more preferably rhenium, iridium, and platinum. More preferred are iridium and platinum.
  • lanthanoid atoms examples include lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.
  • neodymium, europium, and gadolinium are preferable.
  • Examples of the ligand of the complex include G.I. Wilkinson et al., Comprehensive Coordination Chemistry, Pergamon Press, 1987, H.C. Listed by Yersin, “Photochemistry and Photophysics of Coordination Compounds”, published by Springer-Verlag, 1987, Akio Yamamoto, “Organic Metal Chemistry-Fundamentals and Applications,” published by Soukabo, 1982, etc. .
  • Specific ligands are preferably halogen ligands (preferably chlorine ligands), aromatic carbocyclic ligands (eg, cyclopentadienyl anion, benzene anion, or naphthyl anion), Nitrogen-containing heterocyclic ligand (eg, phenylpyridine, benzoquinoline, quinolinol, bipyridyl, or phenanthroline), diketone ligand (eg, acetylacetone), carboxylic acid ligand (eg, acetic acid ligand) , Alcoholate ligands (eg, phenolate ligands), carbon monoxide ligands, isonitrile ligands, and cyano ligands, more preferably nitrogen-containing heterocyclic ligands.
  • the complex may have one transition metal atom in the compound, or may be a so-called binuclear complex having two or more. Different metal atoms may be contained at the same time.
  • Examples of the light emitting material satisfying the relationship (2) are Ir complex, Pt complex, Cu complex, Re complex, W complex, Rh complex, Ru complex, Pd complex, Os complex. Eu complex, Tb complex, Gd complex, Dy complex and Ce complex. Particularly preferred are Ir complexes, Pt complexes, and Re complexes, and among them, Ir complexes, Pt complexes containing at least one coordination mode of metal-carbon bond, metal-nitrogen bond, metal-oxygen bond, and metal-sulfur bond, Re complexes are preferred.
  • fluorescent material generally, benzoxazole, benzimidazole, benzothiazole, styrylbenzene, polyphenyl, diphenylbutadiene, tetraphenylbutadiene, naphthalimide, coumarin, pyran, perinone, oxadiazole, aldazine, pyralidine, cyclohexane Pentadiene, bisstyrylanthracene, quinacridone, pyrrolopyridine, thiadiazolopyridine, cyclopentadiene, styrylamine, aromatic dimethylidin compounds, condensed polycyclic aromatic compounds (anthracene, phenanthroline, pyrene, perylene, rubrene, pentacene, etc.), 8- Various metal complexes represented by quinolinol metal complexes, pyromethene complexes and rare earth complexes, polymers such
  • the light emitting material include the following, but are not limited thereto.
  • the luminescent material used in the present invention is D-2, D-3, D-4, D-5, D-6, D-7, D-8, D from the viewpoint of luminous efficiency and durability.
  • -9, D-10, D-11, D-12, D-13, D-14, D-15, D-16, D-21, D-22, D-23, or D-24 are preferred, D-2, D-3, D-4, D-5, D-6, D-7, D-8, D-12, D-14, D-15, D-16, D-21, D- 22, D-23, or D-24 is more preferable, and D-21, D-22, D-23, or D-24 is still more preferable.
  • the light emitting material in the light emitting layer is preferably contained in an amount of 1% by mass to 50% by mass from the viewpoint of durability and external quantum efficiency with respect to the total mass of the compound generally forming the light emitting layer in the light emitting layer. More preferably 2 to 40% by mass is contained.
  • the thickness of the light emitting layer is not particularly limited, but it is usually preferably 1 nm to 500 nm, and more preferably 5 nm to 200 nm, and more preferably 5 nm to 100 nm, from the viewpoint of light emission efficiency. Is more preferable.
  • a hole transporting host material excellent in hole transportability (sometimes referred to as a hole transportable host) and an electron transporting host compound excellent in electron transportability (electron transportability) May be described as a host).
  • ⁇ Hole-transporting host examples include the following materials. Pyrrole, indole, carbazole, azaindole, azacarbazole, triazole, oxazole, oxadiazole, pyrazole, imidazole, thiophene, polyarylalkane, pyrazoline, pyrazolone, phenylenediamine, arylamine, amino-substituted chalcone, styrylanthracene, fluorenone, hydrazone , Stilbene, silazane, aromatic tertiary amine compounds, styrylamine compounds, aromatic dimethylidin compounds, porphyrin compounds, polysilane compounds, poly (N-vinylcarbazole), aniline copolymers, thiophene oligomers, polythiophenes, etc.
  • Conductive polymer oligomers organic silanes, carbon films, and derivatives thereof.
  • Preferred are indole derivatives, carbazole derivatives, aromatic tertiary amine compounds, and thiophene derivatives, and more preferred are those having a carbazole group in the molecule.
  • a compound having a t-butyl substituted carbazole group is preferable.
  • the electron transporting host in the light emitting layer used in the present invention preferably has an electron affinity Ea of 2.5 eV or more and 3.5 eV or less from the viewpoint of improving durability and lowering driving voltage. More preferably, it is 0.4 eV or less, and further preferably 2.8 eV or more and 3.3 eV or less. Further, from the viewpoint of improving durability and reducing driving voltage, the ionization potential Ip is preferably 5.7 eV or more and 7.5 eV or less, more preferably 5.8 eV or more and 7.0 eV or less, and 5.9 eV or more. More preferably, it is 6.5 eV or less.
  • Such an electron transporting host include the following materials. Pyridine, pyrimidine, triazine, imidazole, pyrazole, triazole, oxazole, oxadiazol, fluorenone, anthraquinodimethane, anthrone, diphenylquinone, thiopyran dioxide, carbodiimide, fluorenylidenemethane, distyrylpyrazine, Fluorine-substituted aromatic compounds, aromatic ring tetracarboxylic acid anhydrides such as naphthalene and perylene, phthalocyanines, and derivatives thereof (which may form condensed rings with other rings), metal complexes of 8-quinolinol derivatives, Examples include various metal complexes represented by metal complexes having metal phthalocyanine, benzoxazole or benzothiazol as a ligand.
  • the electron transporting host include metal complexes, azole derivatives (benzimidazole derivatives, imidazopyridine derivatives, etc.), and azine derivatives (pyridine derivatives, pyrimidine derivatives, triazine derivatives, etc.).
  • metal complex compounds are preferred.
  • the metal complex compound is more preferably a metal complex having a ligand having at least one nitrogen atom, oxygen atom or sulfur atom coordinated to the metal.
  • the metal ion in the metal complex is not particularly limited, but is preferably beryllium ion, magnesium ion, aluminum ion, gallium ion, zinc ion, indium ion, tin ion, platinum ion, or palladium ion, more preferably beryllium ion, Aluminum ion, gallium ion, zinc ion, platinum ion, or palladium ion, and more preferably aluminum ion, zinc ion, or palladium ion.
  • the ligand is preferably a nitrogen-containing heterocyclic ligand (preferably having 1 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, and particularly preferably 3 to 15 carbon atoms).
  • it may be a bidentate or higher ligand, preferably a bidentate or higher and a hexadentate or lower ligand, or a bidentate or higher and lower 6 or lower ligand and a monodentate mixed ligand. preferable.
  • the ligand examples include an azine ligand (for example, pyridine ligand, bipyridyl ligand, terpyridine ligand, etc.), a hydroxyphenylazole ligand (for example, hydroxyphenylbenzimidazole coordination). And a hydroxyphenylbenzoxazole ligand, a hydroxyphenylimidazole ligand, a hydroxyphenylimidazopyridine ligand, etc.), an alkoxy ligand (preferably having 1 to 30 carbon atoms, more preferably 1 carbon atom).
  • azine ligand for example, pyridine ligand, bipyridyl ligand, terpyridine ligand, etc.
  • a hydroxyphenylazole ligand for example, hydroxyphenylbenzimidazole coordination
  • alkoxy ligand preferably having 1 to 30 carbon atoms, more preferably 1 carbon atom.
  • aryloxy ligands preferably having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, for example phenyl Carboxymethyl, 1-naphthyloxy, 2-naphthyloxy, 2,4,6-trimethylphenyl oxy, and 4-biphenyloxy and the like.
  • Heteroaryloxy ligand (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include pyridyloxy, pyrazyloxy, pyrimidyloxy, and quinolyloxy.
  • An alkylthio ligand preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methylthio and ethylthio
  • arylthio ligands Preferably having 6 to 30 carbon atoms, more preferably having 6 to 20 carbon atoms, and particularly preferably having 6 to 12 carbon atoms, such as phenylthio
  • heteroarylthio ligand preferably having 1 carbon atom
  • 2-benzimidazolylthio, 2-benzoxazolylthio, 2-benzthiazolylthio, etc. siloxy ligands (preferably having 1 to 30 carbon atoms, more preferably 3 to 25 carbon atoms). Particularly preferably 6 to 20 carbon atoms, such as triphenylsiloxy group, triethoxysiloxy group and triisopropylsiloxy group), aromatic hydrocarbon anion ligand (preferably having 6 carbon atoms).
  • a phenyl anion preferably a naphthyl anion, an anthranyl anion, etc.
  • an aromatic heterocyclic anion ligand preferably Has 1 to 30 carbon atoms, more preferably 2 to 25 carbon atoms, and particularly preferably 2 to 20 carbon atoms.
  • a nitrogen-containing heterocyclic ligand, an aryloxy ligand, a heteroaryloxy group, a siloxy ligand, an aromatic hydrocarbon anion ligand, or an aromatic heterocyclic anion ligand more preferably Is a nitrogen-containing heterocyclic ligand, aryloxy ligand, siloxy ligand, aromatic hydrocarbon anion ligand, or aromatic heterocyclic anion ligand.
  • Examples of the metal complex electron transporting host include, for example, Japanese Patent Application Laid-Open No. 2002-235076, Japanese Patent Application Laid-Open No. 2004-214179, Japanese Patent Application Laid-Open No. 2004-221106, Japanese Patent Application Laid-Open No. 2004-221105, and Japanese Patent Application Laid-Open No. 2004-221068. And compounds described in JP-A No. 2004-327313 and the like.
  • the triplet lowest excitation level (T1) of the host material is higher than T1 of the phosphorescent light emitting material.
  • the content of the host compound in the present invention is not particularly limited, but from the viewpoint of light emission efficiency and driving voltage, it is 15% by mass to 95% by mass with respect to the total compound mass forming the light emitting layer. Preferably there is.
  • the substrate on the side from which light emitted from the light emitting layer is extracted is preferably a substrate that does not scatter or attenuate.
  • a substrate that does not scatter or attenuate include zirconia stabilized yttrium (YSZ), inorganic materials such as glass, polyesters such as polyethylene terephthalate, polybutylene phthalate, and polyethylene naphthalate, polystyrene, polycarbonate, polyethersulfone, polyarylate, polyimide, and polycycloolefin. , Norbornene resins, and organic materials such as poly (chlorotrifluoroethylene).
  • alkali-free glass is preferably used as the material in order to reduce ions eluted from the glass.
  • soda-lime glass it is preferable to use what gave barrier coatings, such as a silica.
  • barrier coatings such as a silica.
  • an organic material it is preferable that it is excellent in heat resistance, dimensional stability, solvent resistance, electrical insulation, and workability.
  • the shape, structure, size and the like of the substrate are not particularly limited and can be appropriately selected according to the use, purpose, etc. of the light emitting element.
  • the shape of the substrate is preferably a plate shape.
  • the structure of the substrate may be a single layer structure, a laminated structure, may be formed of a single member, or may be formed of two or more members.
  • the substrate can be provided with a moisture permeation preventing layer (gas barrier layer) on the front surface or the back surface.
  • a moisture permeation preventive layer gas barrier layer
  • inorganic materials such as silicon nitride and silicon oxide are preferably used.
  • the moisture permeation preventing layer (gas barrier layer) can be formed by, for example, a high frequency sputtering method.
  • a thermoplastic substrate is used, a hard coat layer, an undercoat layer, or the like may be further provided as necessary.
  • the substrate may be cleaned and / or pretreated before and after electrode preparation or before the organic layer is formed. Cleaning can be performed with water, pure water, ion-exchanged water, acid, alkaline water, or an organic solvent, or immersion and ultrasonic cleaning.
  • pretreatment may be performed for the purpose of decomposing and removing organic substances, the purpose of improving adhesiveness, and the purpose of promoting charge injection from the electrode to the organic layer.
  • pretreatment method UV-ozone treatment, oxygen plasma treatment and the like are preferably used, but are not particularly limited.
  • the anode usually only needs to have a function as an electrode for supplying holes to the organic layer, and there is no particular limitation on the shape, structure, size, etc., depending on the use and purpose of the light-emitting element, It can select suitably from well-known electrode materials.
  • the anode is provided as a transparent anode on the light extraction side, and may or may not be transparent on the side opposite to the light extraction side.
  • Suitable examples of the material for the anode include metals, alloys, metal oxides, conductive compounds, and mixtures thereof.
  • Specific examples of the anode material include conductive metals such as tin oxide doped with antimony and fluorine (ATO, FTO), tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO).
  • Metals such as oxides, gold, silver, chromium, nickel, and mixtures or laminates of these metals and conductive metal oxides, inorganic conductive materials such as copper iodide and copper sulfide, polyaniline, polythiophene, polypyrrole, etc.
  • conductive metal oxides are preferable, and ITO is preferable in terms of productivity, high conductivity, transparency, etc., but may be laminated with other materials, auxiliary electrodes, etc. May be provided
  • the anode is composed of, for example, a wet method such as a printing method and a coating method, a physical method such as a vacuum deposition method, a sputtering method, and an ion plating method, and a chemical method such as a CVD and a plasma CVD method. It can be formed on the substrate according to a method appropriately selected in consideration of suitability with the material to be processed. For example, when ITO is selected as the anode material, the anode can be formed according to a direct current or high frequency sputtering method, a vacuum deposition method, an ion plating method, or the like.
  • the work function of the anode is not limited as long as the work function can inject holes into the hole injection layer or hole transport layer adjacent to the anode, and is preferably 4.0 eV or more and 6.0 eV or less, and 4.5 eV More preferably, it is 5.8 eV or less.
  • the work function of the anode can be adjusted to an arbitrary value by UV ozone treatment or oxygen plasma treatment.
  • the formation position of the anode is not particularly limited and can be appropriately selected according to the use and purpose of the light emitting device, but it is preferably formed on the substrate.
  • the anode may be formed on the entire one surface of the substrate, or may be formed on a part thereof.
  • the patterning for forming the anode may be performed by chemical etching such as photolithography, or may be performed by physical etching such as laser, or vacuum deposition or sputtering with a mask overlapped. It may be performed by a lift-off method or a printing method.
  • the thickness of the anode can be appropriately selected depending on the material constituting the anode and cannot be generally defined, but is usually about 10 nm to 50 ⁇ m, and preferably 50 nm to 20 ⁇ m.
  • the resistance value of the anode is preferably 10 3 ⁇ / ⁇ or less, and more preferably 10 2 ⁇ / ⁇ or less.
  • the anode When the anode is transparent, it may be colorless and transparent or colored and transparent.
  • the transmittance In order to take out light emission from the transparent anode side, the transmittance is preferably 60% or more, and more preferably 70% or more.
  • transparent anode is described in detail in Yutaka Sawada's “New Development of Transparent Electrode Film” published by CMC (1999), and the matters described here can be applied to the present invention.
  • a transparent anode formed using ITO or IZO at a low temperature of 150 ° C. or lower is preferable.
  • the cathode usually has a function as an electrode for injecting electrons into the organic layer, and there is no particular limitation on the shape, structure, size, etc., and it is known depending on the use and purpose of the light-emitting element.
  • the electrode material can be selected as appropriate.
  • the cathode side is a side from which light is extracted, it is preferably transparent or translucent.
  • Examples of the material constituting the cathode include metals, alloys, metal oxides, electrically conductive compounds, and mixtures thereof. Specific examples include alkali metals (eg, LI, Na, K, Cs, etc.), alkaline earth metals (eg, Mg, Ca, etc.), gold, silver, lead, aluminum, sodium-potassium alloys, lithium-aluminum alloys, magnesium. -Rare earth metals such as silver alloys, indium and ytterbium. These may be used alone, but from the viewpoint of achieving both stability and electron injecting properties, two or more of them can be co-deposited or laminated to be suitably used in combination.
  • alkali metals eg, LI, Na, K, Cs, etc.
  • alkaline earth metals eg, Mg, Ca, etc.
  • gold silver, lead, aluminum, sodium-potassium alloys, lithium-aluminum alloys, magnesium.
  • -Rare earth metals such as silver alloys, indium and
  • the work function of the cathode is not particularly limited as long as it is a work function capable of injecting electrons into the adjacent organic layer, preferably 2.5 eV or more and 4.5 eV, more preferably 2.5 eV or more and 4.3 eV or less. is there.
  • the material constituting the cathode is preferably an alkali metal or an alkaline earth metal from the viewpoint of electron injecting property, and a material mainly composed of aluminum is preferable from the viewpoint of excellent storage stability.
  • a laminated structure with a conductive metal oxide may be employed.
  • the material mainly composed of aluminum is aluminum alone, an alloy of aluminum and 0.01% by mass to 10% by mass of alkali metal or alkaline earth metal, or a mixture thereof (for example, lithium-aluminum alloy, magnesium-aluminum alloy). Etc.).
  • the method for forming the cathode is not particularly limited, and can be performed according to a known method.
  • the cathode described above is configured from a wet method such as a printing method or a coating method, a physical method such as a vacuum deposition method, a sputtering method, or an ion plating method, or a chemical method such as CVD or plasma CVD method. It can be formed according to a method appropriately selected in consideration of suitability with the material. For example, when a metal or the like is selected as the cathode material, one or more of them can be simultaneously or sequentially performed according to a sputtering method or the like.
  • Patterning when forming the cathode may be performed by chemical etching such as photolithography, physical etching by laser, or the like, or by vacuum deposition or sputtering with the mask overlaid. It may be performed by a lift-off method or a printing method.
  • the cathode forming position is not particularly limited, and may be formed on the entire organic layer or a part thereof. Further, a dielectric layer made of an alkali metal or alkaline earth metal fluoride or oxide may be inserted between the cathode and the organic layer in a thickness of 0.1 nm to 5 nm. This dielectric layer can also be regarded as a kind of electron injection layer.
  • the dielectric layer can be formed by, for example, a vacuum deposition method, a sputtering method, an ion plating method, or the like.
  • the thickness of the cathode can be appropriately selected depending on the material constituting the cathode and cannot be generally defined, but is usually about 5 nm to 5 ⁇ m, and preferably 10 nm to 1 ⁇ m. Further, the cathode may be transparent or opaque.
  • the transparent cathode can be formed by depositing a thin cathode material to a thickness of 1 nm to 10 nm and further laminating a transparent conductive material such as ITO or IZO.
  • the anode side can be made opaque (reflective electrode), and the cathode side can be made transparent or translucent to make a top emission type element. It is also possible to make a bottom emission type element by making the anode side transparent and the cathode side opaque (reflection electrode). Further, both the anode and the cathode can be made transparent to be a double-sided emission type.
  • the hole injection layer and the hole transport layer are layers having a function of receiving holes from the anode or the anode side and transporting them to the cathode side.
  • the material that can be used for the hole injection layer and the hole transport layer of the present invention is not particularly limited, and may be a low molecular compound, a high molecular compound, or an inorganic material.
  • pyrrole derivatives carbazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives , Silazane derivatives, aromatic tertiary amine compounds, styrylamine compounds, aromatic dimethylidin compounds, phthalocyanine compounds, porphyrin compounds, thiophene derivatives, organic silane derivatives, carbon, phenylazole, phenylazine
  • the inorganic material include silicon oxide, silicon dioxide, germanium oxide, germanium dioxide, germanium oxide silicide, vanadium pentoxide, molybdenum trioxide, aluminum oxide, iron dioxide, iron trioxid
  • the electron-accepting dopant can be contained in the hole injection layer or the hole transport layer of the organic EL device of the present invention.
  • an inorganic compound or an organic compound can be used as long as it has an electron-accepting property and oxidizes an organic compound.
  • examples of the inorganic compound include metal halides such as ferric chloride, aluminum chloride, gallium chloride, indium chloride, and antimony pentachloride, and metal oxides such as vanadium pentoxide and molybdenum trioxide.
  • a compound having a nitro group, halogen, cyano group, trifluoromethyl group or the like as a substituent a quinone compound, an acid anhydride compound, fullerene, or the like can be preferably used.
  • the compounds described in JP-A 2003-229278, JP-A 2004-342614, JP-A 2005-72012, JP-A 2005-166637, JP-A 2005-209643, etc. are preferably used. I can do it.
  • electron accepting dopants may be used alone or in combination of two or more.
  • the amount of the electron-accepting dopant used varies depending on the type of material, but is preferably 0.01% by mass to 50% by mass with respect to the hole transport layer material, and is 0.05% by mass to 20% by mass. It is more preferable that the content be 0.1% by mass to 10% by mass.
  • the thicknesses of the hole injection layer and the hole transport layer are each preferably 500 nm or less from the viewpoint of lowering the driving voltage.
  • the thickness of the hole transport layer is preferably 1 nm to 500 nm, more preferably 5 nm to 300 nm, and even more preferably 10 nm to 200 nm.
  • the thickness of the hole injection layer is preferably from 0.1 nm to 500 nm, more preferably from 0.5 nm to 300 nm, and even more preferably from 1 nm to 200 nm.
  • the hole injection layer and the hole transport layer may have a single-layer structure composed of one or more of the materials described above, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions. .
  • a hydrocarbon compound such as an adamantane compound that is electrically inactive can be added to the hole transport layer by a method disclosed in Japanese Patent Application Laid-Open No. 2005-294249 for the purpose of improving luminous efficiency.
  • the T1 of the hole injection layer and the hole transport layer is not particularly limited, but the difference between the T1 of the hole transport layer adjacent to the light emitting layer and the T1 of the light emitting layer is within 1 eV for the purpose of suppressing exciton diffusion. Preferably there is.
  • the electron injection layer is a layer having a function of receiving electrons from the cathode.
  • a low molecular compound or a high molecular compound may be sufficient.
  • the electron injection layer can contain an electron donating dopant.
  • the electron donating dopant introduced into the electron injecting layer only needs to have an electron donating property and a property of reducing an organic compound, and includes alkali metals such as Li, alkaline earth metals such as Mg, and rare earth metals. Transition metals and reducing organic compounds are preferably used.
  • the metal a metal having a work function of 4.2 eV or less can be preferably used. Specifically, Li, Na, K, Be, Mg, Ca, Sr, Ba, Y, Cs, La, Sm, Gd , And Yb.
  • the reducing organic compound include nitrogen-containing compounds, sulfur-containing compounds, and phosphorus-containing compounds.
  • the materials described in JP-A-6-212153, JP-A-2000-196140, JP-A-2003-68468, JP-A-2003-229278, JP-A-2004-342614, etc. Can be used.
  • electron donating dopants may be used alone or in combination of two or more.
  • the amount of the electron-donating dopant used varies depending on the type of material, but is preferably 0.1% by mass to 30% by mass, and 0.1% by mass to 20% by mass with respect to the electron transport layer material. Is more preferable, and 0.1% by mass to 10% by mass is particularly preferable.
  • the thickness of the electron injection layer is preferably from 0.1 nm to 200 nm, more preferably from 0.2 nm to 100 nm, and even more preferably from 0.5 nm to 50 nm.
  • the electron injection layer may have a single layer structure made of one or more of the materials described above, or may have a multilayer structure made of a plurality of layers having the same composition or different compositions.
  • the hole blocking layer is a layer having a function of preventing holes transported from the anode side to the light emitting layer from passing through to the cathode side.
  • a hole blocking layer can be provided as an organic layer adjacent to the light emitting layer on the cathode side.
  • the hole blocking function can be exhibited when the ionization potential of the hole blocking layer is larger than the ionization potential of the light emitting layer or the hole mobility of the hole blocking layer is smaller than the hole mobility of the light emitting layer.
  • the compound constituting the hole blocking layer include aluminum complexes such as BAlq, triazole derivatives, phenanthroline derivatives such as BCP, and the like.
  • the thickness of the hole blocking layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and even more preferably 10 nm to 100 nm.
  • the hole blocking layer may have a single layer structure composed of one or more of the above-described materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions.
  • an electrically inactive hydrocarbon compound such as an adamantane compound is added to the hole blocking layer by the method disclosed in Japanese Patent Application Laid-Open No. 2005-294248 for the purpose of further improving the luminous efficiency. Can do.
  • an exciton diffusion blocking layer may be provided between the electron transport layer and the light emitting layer.
  • the exciton diffusion blocking layer can be installed for the purpose of suppressing the exciton from diffusing from the light emitting layer to the adjacent layer and lowering the light emission efficiency.
  • the function can be exhibited by using a T1 of the exciton block layer larger than that of the light emitting layer.
  • the electron blocking layer is a layer having a function of preventing electrons transported from the cathode side to the light emitting layer from passing through to the anode side.
  • an electron blocking layer can be provided as an organic layer adjacent to the light emitting layer on the anode side.
  • the electron blocking function can be exerted when the electron affinity of the electron blocking layer is smaller than the electron affinity of the light emitting layer or when the electron mobility of the electron blocking layer is smaller than the electron mobility of the light emitting layer.
  • the compound constituting the electron blocking layer for example, those mentioned as the hole transport material described above can be applied.
  • the thickness of the electron blocking layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and even more preferably 10 nm to 100 nm.
  • the hole blocking layer may have a single layer structure composed of one or more of the above-described materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions.
  • an exciton diffusion blocking layer may be provided between the hole transport layer and the light emitting layer.
  • the exciton diffusion blocking layer can be installed for the purpose of suppressing the exciton from diffusing from the light emitting layer to the adjacent layer and lowering the light emission efficiency.
  • the function can be exhibited by using a T1 of the exciton block layer larger than that of the light emitting layer.
  • the entire organic EL element may be protected by a protective layer.
  • a material contained in the protective layer any material may be used as long as it has a function of preventing materials that promote device deterioration such as moisture and oxygen from entering the device.
  • Specific examples thereof include metals such as In, Sn, Pb, Au, Cu, Ag, Al, Ti, and Ni, MgO, SiO, SiO 2 , Al 2 O 3 , GeO, NiO, CaO, BaO, and Fe 2 O.
  • metal oxides such as Y 2 O 3 , TiO 2 , metal nitrides such as SiN x , SiN x O y , metal fluorides such as MgF 2 , LiF, AlF 3 , CaF 2 , polyethylene, polypropylene, polymethyl Monomer mixture containing methacrylate, polyimide, polyurea, polytetrafluoroethylene, polychlorotrifluoroethylene, polydichlorodifluoroethylene, copolymer of chlorotrifluoroethylene and dichlorodifluoroethylene, tetrafluoroethylene and at least one comonomer Copolymer obtained by copolymerization, cyclic in the copolymer main chain
  • fluorine-containing copolymer having a structure, a water-absorbing substance having a water absorption of 1% or more, and a moisture-proof substance having a water absorption of 0.1% or less.
  • the method for forming the protective layer is not particularly limited, and for example, vacuum deposition, sputtering, reactive sputtering, MBE (molecular beam epitaxy), cluster ion beam, ion plating, plasma polymerization (high frequency) Excited ion plating method), plasma CVD method, laser CVD method, thermal CVD method, gas source CVD method, coating method, printing method, transfer method can be applied.
  • the organic electroluminescent element of this invention may seal the whole element using a sealing container. It can also be sealed with an inorganic film such as SiN or SiON. Furthermore, solid sealing can be performed by a method disclosed in Japanese Patent Application Laid-Open No. 2003-203762. Further, a moisture absorbent or an inert liquid may be sealed in a space between the sealing container and the light emitting element.
  • a moisture absorber For example, barium oxide, sodium oxide, potassium oxide, calcium oxide, sodium sulfate, calcium sulfate, magnesium sulfate, phosphorus pentoxide, calcium chloride, magnesium chloride, copper chloride Cesium fluoride, niobium fluoride, calcium bromide, vanadium bromide, molecular sieve, zeolite, magnesium oxide, and the like.
  • the inert liquid is not particularly limited, and examples thereof include paraffins, liquid paraffins, fluorinated solvents such as perfluoroalkane, perfluoroamine, and perfluoroether, chlorinated solvents, and silicone oils. Can be mentioned.
  • the organic electroluminescence device of the present invention emits light by applying a direct current (which may include an alternating current component as necessary) voltage (usually 2 to 15 volts) or a direct current between the anode and the cathode.
  • a direct current which may include an alternating current component as necessary
  • the driving method of the organic electroluminescence device of the present invention is described in JP-A-2-148687, JP-A-6-301355, JP-A-5-29080, JP-A-7-134558, JP-A-8-234585, The driving methods described in Japanese Patent Application Laid-Open No. 8-24047, Japanese Patent No. 2784615, US Pat. No. 5,828,429, Japanese Patent No. 6023308 can be applied.
  • the device of the present invention can be heat-treated by a method disclosed in Japanese Patent Application No. 2008-48630 and the like for the purpose of driving it more stably after the device is manufactured.
  • current treatment can be performed by a method disclosed in Japanese Patent Application Laid-Open No. 8-185979.
  • the TFT can use any of amorphous silicon, low-temperature polysilicon, and oxide semiconductor.
  • the light-emitting element of the present invention can improve the light extraction efficiency by various known devices. For example, by processing the substrate surface shape (for example, forming a fine concavo-convex pattern), controlling the refractive index of the substrate / ITO layer / organic layer, controlling the film thickness of the substrate / ITO layer / organic layer, etc. It is possible to improve light extraction efficiency and external quantum efficiency. Further, the chromaticity can be further improved by installing a color filter or using a color conversion material. In addition, light emitting materials of other colors can be added to the element of the present invention to reproduce other colors including white. In this case, the light emitting layer may be a single light emitting layer, a plurality of light emitting layers, or a multi-photon element.
  • the element of the present invention can reproduce many colors in combination with other pixels in the panel. In that case, three sub-pixels of red, green, and blue may be combined, and which color can be combined can be determined according to the purpose.
  • the panel driving method can be either active driving or passive driving. Either current driving or voltage driving can be used.
  • the organic electroluminescent element of the present invention can be suitably used for a display element, a display, a backlight, an electrophotography, an illumination light source, a recording light source, an exposure light source, a reading light source, a sign, a signboard, an interior, or optical communication.
  • Example 1 Preparation of organic EL element 1) Preparation of comparative organic EL element 1 A 0.5 mm thick, 2.5 cm square glass substrate is placed in a cleaning container, subjected to ultrasonic cleaning in 2-propanol, and then subjected to UV-ozone treatment for 30 minutes. Went. The following layers were deposited on this transparent anode by vacuum deposition. The vapor deposition rate in the examples of the present invention is 0.2 nm / second unless otherwise specified. The deposition rate was measured using a quartz resonator. The film thicknesses described below were also measured using a crystal resonator.
  • ITO Indium Tin Oxide
  • 2-TNATA Bis [N- (1-naphthyl) -N-pheny] benzidine (abbreviated as ⁇ -NPD) was deposited on the hole injection layer to a thickness of 7 nm.
  • Second hole transport layer The hole transport material 1 was deposited on the hole transport layer to a thickness of 3 nm.
  • Light-emitting layer abbreviated as tris (2-phenylpyridine) iridium (III) (Ir (ppy) 3 ) which is a phosphorescent material of 10 mass% with respect to the host material 1 and the host material 1 on the second hole transport layer
  • the light emitting layer doped with was deposited to a thickness of 30 nm.
  • Second electron transport layer Bis- (2-methyl-8-quinolinolato) -4- (phenyl-phenolate) -aluminum (III) (abbreviated as BAlq) as a second electron transport layer on the light-emitting layer has a thickness of 10 nm. Vapor deposited.
  • First electron transport layer 2,9-dimethyl-4,7-diphenyl-1,10-phenthroline (abbreviated as BCP) was deposited as a first electron transport layer on the second electron transport layer to a thickness of 30 nm.
  • Electron injection layer LiF was deposited on the first electron transport layer to a thickness of 1 nm.
  • Cathode A patterned mask (mask with a light emitting area of 2 mm ⁇ 2 mm) was placed on the electron injection layer, and metal aluminum was deposited to a thickness of 100 nm to form a cathode.
  • the produced laminate was put in a glove box substituted with argon gas, and sealed with a stainless steel sealing can and an ultraviolet curable adhesive (XNR5516HV, manufactured by CHIBA NAGASE Co., Ltd.). In this way, a comparative organic EL element 1 was produced.
  • Comparative Organic EL Element 2 An organic EL element produced in the same manner as the production of comparative organic EL element 1 was subjected to heat treatment in an oven at 85 ° C. for 24 hours to produce comparative organic EL element 2. did.
  • Comparative Organic EL Element 3 The organic EL element produced in the same manner as the comparative organic EL element 1 was subjected to energization treatment at a current density of 10 mA / cm 2 for 24 hours, and the comparative organic EL element 3 was produced. Was made.
  • comparative organic EL element 4 In production of comparative organic EL element 1, as the first electron transport layer, BCP was 0.2 nm / second, Li was vapor deposited at a deposition rate of 0.15 nm / min by co-evaporation to 30 nm. A comparative organic EL element 4 was produced in the same manner as the production of the comparative organic EL element 1 except that the film was formed.
  • Comparative Organic EL Element 5 Production of Comparative Organic EL Element 5
  • the production of the comparative organic EL element 4 was the same as the production of the comparative organic EL element 4 except that Bathphenathhroline (abbreviated as Bphen) was used instead of BCP. Preparation of the comparative organic EL element 5 was produced.
  • Bphen Bathphenathhroline
  • Comparative organic EL element 6 was manufactured in the same manner as comparative organic EL element 5 except that Cs was used instead of Li in the preparation of comparative organic EL element 5. Produced.
  • the organic EL element 6 of the present invention was produced by subjecting the comparative organic EL element 6 to heat treatment at 50 ° C. for 72 hours in an oven.
  • organic EL element 7 of the present invention In production of comparative organic EL element 4, platinum complex 1 was used instead of Ir (ppy) 3 , and BCP and Li of the first electron transport layer were co-evaporated. At that time, the organic EL element 7 of the present invention was prepared in the same manner as the comparative organic EL element 4 except that the film was formed while heating the glass substrate to about 50 ° C. by infrared rays through the co-evaporation step. did.
  • the emission spectrum and emission wavelength were measured using a spectrum analyzer PMA-11 manufactured by Hamamatsu Photonics. Based on these numerical values, the external quantum efficiency at a luminance of 1000 cd / m 2 was calculated by a luminance conversion method.
  • the external quantum efficiency of the comparative organic EL element 1 is set as 100, and the relative value is shown.
  • the relative half-life time of the comparative organic EL element 1 is taken as 100, and the relative value is shown. The obtained results are shown in Table 1.
  • the electron transport layer was doped with Li
  • the organic EL elements 1 to 7 of the present invention in which the electron transport layer is doped with Li and subjected to heat treatment or energization treatment, have a lower drive voltage and improved driving durability than the comparative organic EL elements 4 and 5.
  • the external quantum efficiency was greatly improved as compared with the comparative organic EL elements 4 and 5, and the element performance was greatly improved.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Electroluminescent Light Sources (AREA)

Abstract

L’invention concerne un procédé de fabrication d’un élément électroluminescent organique qui comprend, entre une paire d’électrodes, au moins une couche organique comprenant une couche émettrice de lumière.  Au moins une couche organique contient au moins un type de métal alcalin, de métal alcalino-terreux ou de sel des métaux.  Pendant ou après la formation de pellicule de la couche organique contenant au moins un type de métal alcalin, de métal alcalino-terreux ou de sel des métaux, le procédé consiste en une étape de traitement thermique dans laquelle un traitement thermique est réalisé à une température supérieure ou égale à 50 °C mais inférieure ou égale au point de fusion de la couche organique contenant au moins un type de métal alcalin, de métal alcalino-terreux ou de sel des métaux, ou alternativement une étape d’application d’un courant dans laquelle un courant est appliqué.
PCT/JP2009/068605 2008-11-21 2009-10-29 Élément électroluminescent organique et son procédé de fabrication WO2010058690A1 (fr)

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CN106463634A (zh) * 2014-06-03 2017-02-22 夏普株式会社 有机el元件和制造方法

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JPWO2013118462A1 (ja) 2012-02-06 2015-05-11 株式会社Ｊｏｌｅｄ Ｅｌ表示装置およびその製造方法
CN103367653B (zh) * 2013-07-10 2016-02-03 上海和辉光电有限公司 倒置型有机发光二极管显示器件及其制备方法
JP6519910B2 (ja) * 2014-12-11 2019-05-29 株式会社Ｊｏｌｅｄ 有機ｅｌ素子および有機ｅｌ素子の製造方法

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