JP7052705B2 - Organic electroluminescence device and its manufacturing method - Google Patents

Description

INDUSTRIAL APPLICABILITY The present invention relates to an organic electroluminescence element and a method for manufacturing the same. The organic electroluminescence element has low resistance and excellent adhesion between an organic functional layer and an electrode, and thus has excellent bending resistance, luminous efficiency, and drive life during high-temperature storage. Regarding.

In recent years, organic electroluminescence devices (hereinafter, also referred to as organic EL devices) are required to have various performances such as high efficiency, large area, light weight, and flexibility. Therefore, from the viewpoint of flexibility and cost, it is required to use an inexpensive resin substrate such as a polyethylene terephthalate (PET) substrate, and to adapt it to a mass production method by a roll-to-roll process.

Conventionally, an organic functional layer including an electrode of an organic EL element and a light emitting layer has been produced on a transparent substrate by a vacuum vapor deposition method or a sputtering method. However, in the vacuum vapor deposition method and the sputtering method, it is difficult to manufacture a large-sized organic EL element because the apparatus becomes large and complicated.

Therefore, in the manufacturing process of an organic EL device, a method of forming an organic functional layer or an electrode by a coating process has been proposed from the viewpoint of process simplification and cost reduction (see, for example, Patent Document 1).

In particular, as for the electrode, a transparent electrode is known in which a conductive polymer (PEDOT-PSS) composed of a fine metal wire, poly (3,4-ethylenedioxythiophene) and polystyrene sulfonic acid is coated on a substrate. The conductive polymer has excellent flexibility and can be used in a roll-to-roll process. However, since the volumetric resistance of the conductive polymer itself is high and there is absorption in the visible light region, it is difficult to fabricate an electrode having low resistance while maintaining high transparency.

On the other hand, studies have been made on using silver particles, which are expected to reduce resistance, for manufacturing electrodes of organic EL elements, and for the purpose of providing materials that can improve brightness, silver particles, conjugated compounds adsorbed on silver particles, and A technique for forming an electrode on an organic functional layer by a coating process using a composite composition containing an ionic compound is known (see, for example, Patent Document 2).

However, in the present technology, methanol is used as a dispersion solvent when preparing the complex composition, but when the methanol is applied, the organic functional layer underneath is easily dissolved, resulting in a decrease in luminous efficiency. There are problems such as deterioration of adhesion. Further, since the resistance is still high, it is necessary to increase the drive voltage, and in addition, there is a problem that the voltage rise becomes large during high temperature and high humidity storage. Furthermore, there is no description regarding bending resistance and the like.

Therefore, the emergence of an organic EL device having low resistance, excellent adhesion between the organic functional layer and the electrode, and excellent bending resistance, luminous efficiency, and drive life during high-temperature storage is awaited.

Japanese Unexamined Patent Publication No. 2006-190759 Japanese Unexamined Patent Publication No. 2012-238576

The present invention has been made in view of the above problems and situations, and the problems to be solved are low resistance, excellent adhesion between the organic functional layer and the electrode, bending resistance and luminous efficiency during high-temperature storage, and light emission efficiency. It is to provide an organic electroluminescence element having an excellent drive life.

The present inventor is an organic electroluminescence element having at least a substrate and an organic functional layer sandwiched between an anode and a cathode in a process of examining the cause of the problem in order to solve the above problems. We have found that the inclusion of an organic substance, which is a dispersant, in the anode or cathode improves the adhesion to the adjacent organic functional layer, and is excellent in bending resistance, light emission efficiency, and drive life during high-temperature storage. It came to be done.

That is, the above-mentioned problem according to the present invention is solved by the following means.

1. 1. An organic electroluminescence device having at least a substrate and an organic functional layer sandwiched between an anode and a cathode.
The electrode (K) of at least one of the anode and the cathode is a metal thin film layer containing metal particles and a non-volatile organic substance.
The mass ratio of the total content (B) of the non-volatile organic substance to the total content (A) of the metal particles in the portion of the electrode (K) in the range of 10 nm in the thickness direction from the interface on the organic functional layer side. An organic electroluminescence element having (B / A) in the range of 0.01 to 0.10.

2. 2. The organic electroluminescence device according to item 1, wherein the electrode (K) is an electrode on the side far from the substrate with respect to the organic functional layer.

3. 3. The mass ratio (B / A) is in the range of 0.01 to 0.05 in the portion of the electrode (K) in the range of 10 nm in the thickness direction from the interface opposite to the organic functional layer side. The organic electroluminescence device according to the first or second paragraph.

4. The organic electroluminescence device according to any one of items 1 to 3, wherein the electrode (K) contains water in the range of 20 to 300 μg per 1 mm ³ .

5. The organic electroluminescence device according to any one of items 1 to 4, wherein the electrode (K) contains an organic solvent in the range of 4 to 100 μg per 1 mm ³ .

6. The organic electroluminescence device according to any one of items 1 to 5, wherein the metal of the metal particles is silver.

7. The organic electroluminescence device according to any one of items 1 to 6, wherein the substrate is a flexible substrate.

8. The method for manufacturing an organic electroluminescence device for manufacturing the organic electroluminescence device according to any one of the items 1 to 7.
A step of forming either one of the anode and the cathode and an organic functional layer on the substrate in this order.
A step of preparing a dispersion liquid containing the metal particles and the non-volatile organic substance, and
It comprises a step of applying the dispersion liquid on the organic functional layer and drying to form the electrode (K).
The organic electroluminescence is characterized in that the dispersion is prepared so that the mass ratio of the content of the non-volatile organic substance to the content of the metal is in the range of 1: 0.01 to 1: 0.10. Method of manufacturing the element.

9. Further, the present invention comprises a step of forming the electrode (K) from the organic functional layer side in a two-layer structure of a first electrode layer (K1) and a second electrode layer (K2).
In the process
A dispersion is prepared so that the mass ratio of the content of the non-volatile organic substance to the content of the metal is in the range of 1: 0.01 to 1: 0.10, and the dispersion is used as the organic functional layer. It is applied and dried on top to form a first electrode layer (K1), then
A dispersion is prepared so that the mass ratio of the content of the non-volatile organic substance to the content of the metal is in the range of 1: 0.01 to 1: 0.05, and the dispersion is used as the first dispersion. The method for manufacturing an organic electroluminescence element according to Item 8, wherein a second electrode layer (K2) is formed by applying and drying on the electrode layer (K1).

10. The step of applying the dispersion liquid by a dispenser or an inkjet printing method, and
The method for producing an organic electroluminescence device according to item 8 or 9, wherein the applied dispersion liquid is dried and then fired.

By the above means of the present invention, it is possible to provide an organic electroluminescence device having low resistance and excellent adhesion between an organic functional layer and an electrode, and thus having excellent bending resistance, luminous efficiency and drive life during high temperature storage.

Although the mechanism of expression or mechanism of action of the effect of the present invention has not been clarified, it is inferred as follows.

When at least one of the anode and the cathode electrodes is formed on the organic functional layer including the light emitting layer by a coating process, a dispersion of metal particles can be prepared and coated as a metal thin film layer. In the dispersion, the metal particles are protected and dispersed by the dispersant. The present inventors considered that the dispersant becomes a resistance component and should be reduced as much as possible. However, since the electrode contains the organic substance which is the dispersant, the adhesion to the lower organic functional layer is achieved. It was found that the results were improved, and that the bending resistance, the luminous efficiency at high temperature storage, and the drive life were excellent.

Originally, the adhesion between the interface between inorganic and organic substances is often poor, but the inclusion of a small amount of organic substances in the metal electrode strengthens the van der Waals force with respect to the underlying organic functional layer, resulting in adhesion. It is estimated that we were able to improve. Furthermore, it is presumed that by forming a metal thin film layer using metal particles, an organic electroluminescence device having low resistance and excellent luminous efficiency and drive life during high-temperature storage was obtained. To.

Cross section of cutting sample Cross-sectional view showing an example of the layer structure of the organic EL element of the present invention. Cross-sectional view when the electrode (K) according to the present invention has a two-layer structure.

The organic electroluminescence device of the present invention is an organic electroluminescence device having at least a substrate and an organic functional layer sandwiched between an anode and a cathode.
The electrode (K) of at least one of the anode and the cathode is a metal thin film layer containing metal particles and a non-volatile organic substance, and is in the thickness direction from the interface of the electrode (K) on the organic functional layer side. The mass ratio (B / A) of the total content (B) of the non-volatile organic substance to the total content (A) of the metal particles in the range of 10 nm is in the range of 0.01 to 0.10. It is characterized by being. This feature is a technical feature common to or corresponding to the following embodiments.

As an embodiment of the present invention, from the viewpoint of exhibiting the effect of the present invention, the fact that the electrode (K) is an electrode on the side far from the substrate with respect to the organic functional layer effectively utilizes the effect of the present invention. From the viewpoint of

Further, the mass ratio (B / A) is within the range of 0.01 to 0.05 in the portion of the electrode (K) in the range of 10 nm in the thickness direction from the interface opposite to the organic functional layer side. This is preferable from the viewpoint of achieving both adhesion and low resistance because the organic substance has a concentration gradient inside the electrode and the concentration of the organic substance can be increased on the organic functional layer side.

It is preferable that the electrode (K) contains water in the range of 20 to 300 μg per 1 mm ³ from the viewpoint of suppressing the dissolution of the organic functional layer which is an adjacent layer.

Further, it is preferable that the electrode (K) contains an organic solvent in the range of 4 to 100 μg per 1 mm ³ from the viewpoint of improving the coatability and forming a uniform metal thin film layer.

Further, it is preferable that the metal of the metal particles is silver from the viewpoint of providing an organic electroluminescence device having excellent luminous efficiency and drive life.

Further, it is preferable that the substrate is a flexible substrate from the viewpoint of flexibility and weight reduction of the organic electroluminescence element.

The method for producing an organic electroluminescence element of the present invention includes a step of forming either one of the anode and the cathode and an organic functional layer in this order on the substrate, and a dispersion containing the metal particles and the non-volatile organic substance. It has a step of preparing a liquid and a step of applying the dispersion liquid on the organic functional layer and drying to form the electrode (K), and the dispersion liquid is non-volatile with respect to the metal content. It is characterized in that the mass ratio of the content of organic matter is adjusted to be in the range of 1: 0.01 to 1: 0.10.

Further, the present invention includes a step of forming the electrode (K) from the organic functional layer side in a two-layer structure of a first electrode layer (K1) and a second electrode layer (K2). A dispersion is prepared so that the mass ratio of the content of the non-volatile organic substance to the content is in the range of 1: 0.01 to 1: 0.10, and the dispersion is applied onto the organic functional layer. And dried to form the first electrode layer (K1), and then the mass ratio of the content of the non-volatile organic matter to the content of the metal is in the range of 1: 0.01 to 1: 0.05. The dispersion liquid is prepared so as to be Since the gradient can be easily produced and the concentration of the organic substance at the interface on the organic functional layer side can be increased, this is a preferable embodiment from the viewpoint of achieving both adhesion and low resistance.

The dispersion liquid has a step of applying by a dispenser or an inkjet printing method and a step of drying and then firing the applied dispersion liquid to produce a highly productive and low resistance organic electroluminescence element. From the viewpoint, it is a preferable manufacturing method.

Hereinafter, the present invention, its constituent elements, and modes and embodiments for carrying out the present invention will be described in detail. In addition, in this application, "-" is used in the meaning which includes the numerical values described before and after it as the lower limit value and the upper limit value.

<< Overview of the organic electroluminescence device of the present invention >>
The organic electroluminescence element of the present invention is an organic electroluminescence element having at least a substrate and an organic functional layer sandwiched between an anode and a cathode, and is an electrode (K) of at least one of the anode and the cathode. Is a metal thin film layer containing metal particles and a non-volatile organic substance, and the total content of the metal particles (in the range portion of 10 nm in the thickness direction from the interface on the organic functional layer side of the electrode (K)). The mass ratio (B / A) of the total content (B) of the non-volatile organic substance to A) is in the range of 0.01 to 0.10.

The mass ratio of the metal particles and the non-volatile organic substance in the range of 10 nm in the thickness direction from the interface on the organic functional layer side of the electrode (K) can be measured by the following method.

FIG. 1 is a cross-sectional view of a cutting sample using the organic EL element of the present invention.

The organic EL element (1) has an organic functional layer (4) on a substrate (2), the corresponding electrodes (K) and (3) are laminated on the organic functional layer, and the organic functional layer (4) is laminated. ) And the substrate (2) have the other electrode.

Using the organic EL element (1), for example, a diagonal cutting device NN-04T manufactured by Daipra Wintes Co., Ltd. is used to prepare a cross section of the organic EL element sample at an angle of 0.20 degrees.

A 2.86 μm portion (7) from the interface (6) between the organic functional layer (4) and the electrode in the cut section is a time-of-flight secondary ion mass spectrometer (TOF-SIMS: manufactured by Physical Electronics Co., Ltd.). By analyzing the composition using the above, the composition of the portion 10 nm in the thickness direction from the interface can be obtained.

A sample in which the mass ratio of the metal particles and the organic substance is changed is prepared in advance, and a calibration curve for converting the detection signal and the mass is prepared in the time-of-flight type secondary ion mass spectrometer.

Further, the mass ratio of the content of the metal particles and the non-volatile organic substance in the range of 10 nm in the thickness direction from the interface on the side opposite to the organic functional layer side can be measured by the same method.

<< Components of organic EL elements >>
In the organic EL element of the present invention, at least one of the electrodes (K) of the anode or the cathode in contact with the organic functional layer formed on the substrate is a metal thin film layer containing metal particles and a non-volatile organic substance. The mass ratio (B / A) of the mass (B) of the non-volatile organic substance to the mass (A) of the metal particles in the range of 10 nm in the thickness direction from the interface of the electrode (K) on the organic functional layer side. Is in the range of 0.01 to 0.10.

The electrode (K) according to the present invention is an electrode of at least one of an anode and a cathode, but a preferred embodiment of the present invention is the electrode (K) from the viewpoint of effectively utilizing the effect of the present invention. However, it is preferable that the electrode is on the side far from the substrate with respect to the organic functional layer. For the electrodes on the substrate side, for example, when a glass base material is used as the substrate or a gas barrier film is used, the adhesion between the substrate surface and the electrodes in contact with the substrate is not a problem because the inorganic substances are laminated. Further, even if a solvent is used for coating and forming the electrode, the effect on the lower layer is small.

However, since the electrode on the side far from the substrate with respect to the organic functional layer is a laminate of an organic substance-containing layer and an inorganic compound-containing electrode, a problem of adhesion is likely to occur, and a solvent is used to apply the electrode. If so, the degree to which the solvent diffuses into the organic functional layer and affects the function is large.

Therefore, it is preferable that the electrode (K) according to the present invention is applied to the electrode on the side far from the substrate with respect to the organic functional layer to sufficiently exhibit the effect of the present invention. Normally, in the case of a general configuration of an organic EL element, the electrode on the side far from the substrate is a cathode. Therefore, the electrode (K) according to the present invention will be described below as a cathode, but the present invention is not limited thereto. Depending on the layer structure, it may be an anode.

FIG. 2 is a cross-sectional view showing an example of the layer structure of the organic EL element of the present invention.

The organic EL element EL of the present invention is preferably used as a substrate having gas barrier properties by forming a gas barrier layer 11 on a flexible substrate 10. An anode 12 is formed on the substrate, and a hole injection layer / hole transport layer / electron blocking layer, a first organic functional layer 13 of sugar, a light emitting layer 14, and a hole blocking layer / electron transport layer / electron are formed on the anode 12. The second organic functional layer 15 such as the injection layer is laminated and formed in this order to form the organic functional layer unit 16. Next, a cathode 17, which is an electrode (K) according to the present invention, is formed as an upper layer of the second organic functional layer 15, and the organic functional layer and the electrode are placed on a sealing substrate 19 via a sealing adhesive layer 18. It is sealed to form an organic EL element.

FIG. 3 is a cross-sectional view when the electrode (K) according to the present invention has a two-layer structure.

An electrode (K) having a two-layer structure consisting of a first electrode layer (K1) and a second electrode layer (K2) is formed on the lower second organic functional layer 15 to serve as a cathode 17.

Hereinafter, the details of each element of the organic EL element of the present invention will be described.

[1] Substrate The substrate 10 applicable to the organic EL element (EL) is not particularly limited, and examples thereof include types such as glass and plastic. Further, it is preferable that the substrate has flexibility. The flexibility referred to in the present invention means that the substrate is cracked or chipped by visual confirmation after repeating winding and opening 10 times around a rod made of ABS resin (acrylonitrile-butadiene-styrene copolymer resin) having a diameter of 5 mm. It is a characteristic that is not damaged.

In the present invention, the substrate 10 arranged on the outermost surface (light emitting surface side) is preferably a transparent substrate, and "transparent" means that the average light transmittance in the visible light region is 50% or more. Good, preferably 60% or more, more preferably 70% or more, and particularly preferably 80% or more.

That is, in the present invention, in the configuration in which the light L is taken out from the substrate 10 side, the substrate 10 needs to be a transparent material, and examples of the transparent flexible substrate 10 preferably used include glass, quartz, and a resin substrate. It is possible, and more preferably, it is a resin substrate from the viewpoint of flexibility and safety.

Examples of the resin substrate applicable to the present invention include polyesters such as polyethylene terephthalate (abbreviation: PET) and polyethylene naphthalate (abbreviation: PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, and cellulose triacetate (abbreviation: TAC). , Cellulosic acetate butyrate, cellulose acetate propionate (abbreviation: CAP), cellulose acetate phthalate, cellulose esters such as cellulose nitrate and their derivatives, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, Polycarbonate (abbreviation: PC), norbornene resin, polymethylpentene, polyether ketone, polyimide, polyethersulfone (abbreviation: PES), polyphenylene sulfide, polysulfones, polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon , Polymethylmethacrylate, acrylics and polyarylates, cycloolefins such as Arton (trade name, manufactured by JSR) and Apel (trade name, manufactured by Mitsui Kagaku Co., Ltd.) and the like.

Among these resin substrates, transparent resin films such as polyethylene terephthalate (abbreviation: PET), polybutylene terephthalate, and polyethylene naphthalate (abbreviation: PEN), which are polyester films, are flexible in terms of cost and availability. It is preferably used as a resin substrate of.

The polyester constituting the polyester film is not particularly limited, but a polyester having a film-forming property having a dicarboxylic acid component and a diol component as main constituent components is preferable. Among them, terephthalic acid and 2,6-naphthalenedicarboxylic acid are the main components of the dicarboxylic acid component, and ethylene glycol and 1,4-cyclohexanedimethanol are the main components of the diol component from the viewpoint of transparency, mechanical strength, dimensional stability, etc. As the transparent resin film in which polyester as a component is preferable, a biaxially oriented polyester film is particularly preferable, but an unstretched or uniaxially stretched polyester film stretched to at least one can also be used. A stretched film is preferable from the viewpoint of improving strength and suppressing thermal expansion.

When a transparent resin film is used as the transparent substrate, in order to facilitate handling, calcium carbonate, calcium phosphate, silica, kaolin, talc, titanium dioxide, alumina, barium sulfate, calcium fluoride, as long as the transparency is not impaired, It is preferable to contain inorganic fine particles such as lithium fluoride, zeolite and molybdenum sulfide, and organic fine particles such as crosslinked polymer fine particles and calcium oxalate. It is also preferable to contain a stabilizer, a lubricant, a cross-linking agent, an anti-blocking agent, an antioxidant, a dye, a pigment, an ultraviolet absorber and the like.

The thickness of the resin substrate is preferably a thin film resin substrate in the range of 10 to 500 μm, more preferably in the range of 30 to 400 μm, and particularly preferably in the range of 50 to 300 μm. be. When the thickness is 10 μm or more, the organic EL element can be stably held, and when the thickness is 500 μm or less, a thin organic EL element can be provided.

Further, the gas barrier layer 11 can be provided on the substrate 10 according to the present invention. The gas barrier layer is not particularly limited as long as it has a blocking effect on gas, moisture, etc., and a conventionally known gas barrier layer can be appropriately selected and applied.

The gas barrier layer may be not only an inorganic material coating, but also a coating made of a composite material with an organic material or a hybrid coating obtained by laminating these coatings. As for the performance of the gas barrier layer, the water vapor permeability (environmental conditions: 25 ± 0.5 ° C., relative humidity (90 ± 2)%) conforming to JIS (Japanese Industrial Standards) -K7129 (2008) is about 0. 01 g / ( ^m 2.24 h) or less, JIS-K7126 (2006) compliant oxygen permeability of about 0.01 mL / ( ^m 2.24 h · atm) or less, resistance of 1 x 10 ¹² Ω · cm or more It is preferable that the insulating film has a light transmittance having a gas barrier property such that the light transmittance is about 80% or more in the visible light region.

As the material for forming the gas barrier layer, any material can be used as long as it is a material that causes deterioration of the organic EL element and can suppress the infiltration of gas such as water or oxygen into the organic EL element.

For example, it can be composed of a film made of an inorganic material such as silicon oxide, silicon nitride, silicon nitride, silicon carbide, silicon carbide, aluminum oxide, aluminum nitride, titanium oxide, zirconium oxide, niobium oxide, and molybdenum oxide. It is preferable to use a silicon compound such as silicon nitride or silicon oxide as a main raw material.

As a method for forming the gas barrier layer, a conventionally known film forming method can be appropriately selected and used. For example, a vacuum vapor deposition method, a sputtering method, a magnetron sputtering method, a molecular beam epitaxy method, a cluster ion beam method, and an ion play method can be used. Ting method, plasma polymerization method, atmospheric pressure plasma polymerization method (see JP-A-2004-68143), plasma CVD (Chemical Vapor Deposition) method, laser CVD method, thermal CVD method, ALD (
Atomic layer deposition) method and wet coating method using polysilazane or the like can also be applied.

[2] Electrode The electrode (K) according to the present invention is an electrode of at least one of an anode and a cathode, is a metal thin film layer containing metal particles and a non-volatile organic substance, and is the electrode (K). The mass ratio (B / A) of the total content (B) of the non-volatile organic substance to the total content (A) of the metal particles in the portion in the range of 10 nm in the thickness direction from the interface on the organic functional layer side of the above. , 0.01 to 0.10.

Further, it is preferable that the electrode (K) according to the present invention is applied to the electrode on the side far from the substrate with respect to the organic functional layer to sufficiently exhibit the effect of the present invention. Normally, in the case of a general configuration of an organic EL element, the electrode on the side far from the substrate is a cathode. Therefore, the electrode (K) according to the present invention will be described below as a cathode [2.1] Electrode (K). (cathode)
The electrode (K) (hereinafter, also referred to as a cathode) according to the present invention is a metal thin film layer containing metal particles and a non-volatile organic substance.

As the cathode, a metal having a small work function (4 eV or less) (referred to as an electron-injectable metal) or an alloy having an alloy as an electrode material is used.

The metal particles are preferably metal fine particles, which are also called metal nanoparticles because of their shape.

The metal particles are fine particles such as gold, silver, ruthenium, rhodium, palladium, osmium, iridium, platinum, and copper, and in particular, particles having a particle size of 1 μm or less. Of these, gold, silver, platinum, and copper are preferable, and silver is particularly preferable.

The aspect ratio of the metal particles is preferably in the range of 1 to 5, and more preferably in the range of 1 to 3. When the aspect ratio is close to 1 and close to a true sphere, the density of the film made of metal particles is high, the contact area with the organic functional layer is also high, and the adhesion and bending resistance are improved.

The average particle size of the metal particles is preferably in the range of 10 to 100 nm, more preferably in the range of 15 to 80 nm, and most preferably in the range of 20 to 60 nm. The average particle size of the metal particles can be measured by various methods, but in the present invention, it is obtained from the measurement of the particle size distribution using a particle size measuring device (Zetasizer Nano S, manufactured by Malvern Instruments) by a dynamic light scattering method. Value.

Next, the non-volatile organic substance according to the present invention means an organic substance having a boiling point of 300 ° C. or higher.

The non-volatile organic substance enhances the dispersion stability of the metal particles in the dispersion liquid of the metal particles, and improves the adhesion between the organic functional layer and the electrode formed of the metal particles in the organic EL element. Is added.

Non-volatile organic substances include styrene-acrylic acid copolymer, styrene-acrylic acid-acrylic acid alkyl ester copolymer, styrene-acrylic acid copolymer, styrene-maleic acid-acrylic acid alkyl ester copolymer, and styrene. -Maleic acid copolymer, styrene-methacrylic acid-acrylic acid alkyl ester copolymer, styrene-methacrylic acid copolymer, styrene-maleic acid half ester copolymer, vinylnaphthalene-acrylic acid copolymer, vinylnaphthalene- Maleic acid copolymers, polyvinyl alcohols, gelatins, celluloses, thickening polysaccharides, polymers having amines and aliphatics (for example, polyethyleneimine) and the like can be used.

Further, the high molecular weight pigment dispersant described in the specification paragraphs [0020] to [0037] of JP-A-11-80647, and the specification paragraphs [0030] to [0039] of JP-A-2018-81246. Radical-polymerizable monomers and materials such as polymers or surfactants described in paragraphs [0027] and [0028] of JP-A-2008-117656 can also be used.

When preparing a dispersion liquid containing metal particles and a non-volatile organic substance, it is preferable to use the following predetermined amounts of water and an organic solvent.

It is preferable that the coating solvent of the cathode is water from the viewpoint of suppressing the influence of dissolution due to the diffusion of the solvent in the lower layer, but when a small amount of an organic solvent or the like is added, the wettability and spreadability of the dispersion liquid on the organic functional layer is good. This is preferable because the adhesion between the organic functional layer and the electrode formed of the metal particles and the non-volatile organic substance is further improved.

That is, the electrode (K) according to the present invention preferably contains water in the range of 20 to 300 μg per 1 mm ³ or an organic solvent in the range of 4 to 100 μg per 1 mm ³ . It is preferable to use water and an organic solvent in the preparation of the dispersion so that the amount is in the range. The mixing ratio of water and the organic solvent is preferably in the range of 5: 5 to 9: 1 in terms of mass ratio of water: organic solvent, and more preferably in the range of 6: 4 to 8: 2.
The amount of water and alcohol in the electrode (K) can be measured by a gas chromatograph mass spectrometer, a temperature rise thermal desorption analyzer, or the like. Further, as a specific device, the measurement can be performed by a thermal desorption analyzer manufactured by Denshi Kagaku Co., Ltd.

As the organic solvent, it is preferable to use an organic solvent having a boiling point in the range of 50 to 250 ° C.

Of these, alcohol is preferable, for example, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-methylpropyl alcohol, ethylene glycol, propylene glycol, methoxyethanol, 1-methoxy-2-propanol, propylene glycol monopropyl. Ether, 3-methoxy-1-butanol, 1-ethoxy-2-propanol, 2-n-butoxyethanol, methylpropylene diglycol, 2- (2-n-butoxyethoxy) ethanol and the like can be used.

The method for manufacturing an organic EL element of the present invention comprises a step of forming an electrode other than the electrode (K) according to the present invention, preferably an anode and an organic functional layer, in this order on the substrate, and the metal particles and the non-volatile substance. The step of preparing the dispersion liquid containing the organic substance of the above so that the mass ratio of the content of the non-volatile organic substance to the content of the metal is in the range of 1: 0.01 to 1: 0.10. It is characterized by having a step of applying and drying the liquid on the organic functional layer to form the electrode (K).
As a dispersion method when preparing the dispersion liquid, the metal particles, the non-volatile organic substance, and a solvent may be mixed and dispersed by a dispersion method such as ultrasonic dispersion, high shear force dispersion, or media dispersion. can.
The method for applying the dispersion liquid containing the metal particles, the non-volatile organic substance and the solvent is not limited, but the dispenser method, the inkjet printing method, the die coating method and the like are preferable because the film thickness can be appropriately controlled. Above all, the dispenser method and the inkjet printing method are preferable from the viewpoint of ease and accuracy in coating.

The drying method after application of the dispersion liquid containing metal particles and non-volatile organic substances is not particularly limited, but it is preferable to perform initial drying by infrared drying, blast drying, or warm air drying, and then a constant temperature bath or hot. It is preferable to bake on a plate or the like. By drying in this way, it is possible to appropriately control the concentration of the non-volatile organic substance in the range portion of 10 nm in the thickness direction from the interface on the organic functional layer side of the electrode formed of the metal particles.

The electrode (K) according to the present invention is coated and formed in a two-layer structure consisting of a first electrode layer (K1) and a second electrode layer (K2), and is a non-volatile organic substance near the interface with the organic functional layer. It is preferable to adjust the content of. The preferred reason is that the conductivity is lowered by adding a non-volatile organic substance to the electrode formed of metal particles. The electrode formed of metal particles in contact with the organic functional layer has a non-volatile organic substance added sufficiently for adhesion, and the electrode formed of metal particles having a low non-volatile organic substance content and low resistance in the upper layer thereof. By providing the above, it is possible to secure higher conductivity in addition to adhesion and improve the power efficiency of the organic EL element.
Therefore, the mass ratio (B / A) is within the range of 0.01 to 0.05 in the portion of the electrode (K) in the range of 10 nm in the thickness direction from the interface opposite to the organic functional layer side. Is preferable.

As a preferred embodiment of the present invention, a step of forming the electrode (K) according to the present invention from the organic functional layer side in a two-layer structure of a first electrode layer (K1) and a second electrode layer (K2) is performed. In the step, the dispersion is prepared so that the mass ratio of the content of the non-volatile organic substance to the content of the metal is in the range of 1: 0.01 to 1: 0.10. The dispersion was applied onto the organic functional layer and dried to form a first electrode layer (K1), and then the mass ratio of the non-volatile organic matter content to the metal content was 1: 0. A dispersion is prepared so as to be in the range of 01 to 1: 0.05, and the dispersion is applied and dried on the first electrode layer (K1) to form a second electrode layer (K2). It is preferable to do so.

The sheet resistance of the cathode as a whole is several hundred Ω / sq. The following is preferable, and the thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 to 500 nm.

[2.2] Anode As the anode in the organic EL element, a metal, an alloy, an electrically conductive compound having a large work function (4 eV or more, preferably 4.5 eV or more) and a mixture thereof as an electrode material are preferably used. Be done. Specific examples of such an electrode material include metals such as Au and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ , and ZnO. Further, a material such as indium / zinc oxide (IZO) that is amorphous and can produce a transparent conductive film may be used.

For the anode, a thin film may be formed by forming a thin film of these electrode materials by a method such as thin film deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method, or when pattern accuracy is not required so much (about 100 μm or more). The pattern may be formed through a mask having a desired shape during vapor deposition or sputtering of the electrode material.

Alternatively, when a coatable substance such as an organic conductive compound is used, a wet film forming method such as a printing method or a coating method can also be used. When emitting light from this anode, it is desirable to increase the transmittance to more than 10%, and the sheet resistance as the anode is several hundred Ω / sq. The following is preferable.
The film thickness of the anode depends on the material, but is usually selected in the range of 10 nm to 1 μm, preferably in the range of 10 to 200 nm.

[3] Organic Functional Layer In the following configuration description, for convenience, only the configuration consisting of one light emitting layer (14) is shown, and the description of the laminated tandem configuration is omitted.

A typical example of the configuration of the organic EL element is shown below. The layer excluding the anode and cathode is the organic functional layer.

(I) Electron / organic functional layer unit [first organic functional layer (hole injection transport layer) / light emitting layer / second organic functional layer] / cathode (ii) anode / organic functional layer unit [first organic Functional layer (hole injection transport layer) / light emitting layer / second organic functional layer (hole blocking layer / electron injection transport layer)] / cathode (iii) anode / organic functional layer unit [first organic functional layer (first organic functional layer) Hole injection transport layer / electron blocking layer) / light emitting layer / second organic functional layer (hole blocking layer / electron injection transport layer)] / cathode (iV) anode / organic functional layer unit [first organic functional layer (Hole injection layer / hole transport layer) / light emitting layer / second organic functional layer (electron transport layer / electron injection layer)] / cathode (V) anode / organic functional layer unit [first organic functional layer (first organic functional layer) Hole injection layer / hole transport layer) / light emitting layer / second organic functional layer (hole blocking layer / electron transport layer / electron injection layer)] / cathode (Vi) anode / organic functional layer unit [first Organic functional layer (hole injecting layer / hole transporting layer / electron blocking layer) / light emitting layer / second organic functional layer (hole blocking layer / electron transporting layer / electron blocking layer)] / cathode When forming a layer, a non-luminescent intermediate layer may be provided between the light emitting layers. The intermediate layer may be a charge generation layer or may have a multi-photon unit configuration.

Regarding the outline of the organic EL element applicable to the present invention, for example, Japanese Patent Application Laid-Open No. 2013-157634, Japanese Patent Application Laid-Open No. 2013-168552, Japanese Patent Application Laid-Open No. 2013-1773661, Japanese Patent Application Laid-Open No. 2013-187211, JP-A-2013 2013-191644, 2013-191804, 2013-225678, 2013-235994, 2013-243234, 2013-243236, 2013-2013 242366, 2013-243371, 2013-245179, 2014-003249, 2014-003299, 2014-013910, 2014-017493 Examples thereof include the configurations described in Japanese Patent Application Laid-Open No. 2014-017494.

Specific examples of the tandem type organic EL element include, for example, US Pat. No. 6,337,492, US Pat. No. 7,420,203, US Pat. No. 7,473,923, US Pat. No. 6,872,472, US Patent. Japanese Patent No. 6107734, US Pat. No. 6,337,492, Japanese Patent Application Laid-Open No. 2006-228712, Japanese Patent Application Laid-Open No. 2006-24791, Japanese Patent Application Laid-Open No. 2006-49393, Japanese Patent Application Laid-Open No. 2006-49394, Japanese Patent Application Laid-Open No. 2006- 49396, 2011-96679, 2005-340187, 4711424, 3496681 Japanese Patent Application Laid-Open No. 2009-07629, Japanese Patent Application Laid-Open No. 2008-078441, Japanese Patent Application Laid-Open No. 2007-059848, Japanese Patent Application Laid-Open No. 2003-272860, Japanese Patent Application Laid-Open No. 2003-045676, International Publication No. 2005/009087, Examples thereof include the element configurations and constituent materials described in International Publication No. 2005/094130, but the present invention is not limited thereto.

Further, each layer constituting the organic EL element will be described.

(Light emitting layer)
As the light emitting layer constituting the organic EL element (EL), a phosphorescent light emitting compound or a fluorescent compound can be used as the light emitting material, but in the present invention, the phosphorescent light emitting compound is particularly contained as the light emitting material. The configuration is preferable.

This light emitting layer is a layer in which the electrons injected from the electrode or the electron transport layer and the holes injected from the hole transport layer recombine and emit light, and the light emitting portion is in the layer of the light emitting layer. However, it may be an interface between a light emitting layer and an adjacent layer.

The configuration of such a light emitting layer is not particularly limited as long as the contained light emitting material satisfies the light emitting requirements. Further, there may be a plurality of layers having the same emission spectrum and emission maximum wavelength. In this case, it is preferable to have a non-luminous intermediate layer between each light emitting layer.

The total thickness of the light emitting layer is preferably in the range of 1 to 100 nm, and more preferably in the range of 1 to 30 nm because a lower drive voltage can be obtained. The total thickness of the light emitting layer is the thickness including the non-light emitting intermediate layer when there is a non-light emitting intermediate layer between the light emitting layers.

The light emitting layer as described above is a known method such as a vacuum deposition method, a spin coating method, a casting method, a LB method (Langmuir Brodgett method), an inkjet method, or the like, using a light emitting material or a host compound described later. Can be formed by.

Further, the light emitting layer may be a mixture of a plurality of light emitting materials, or may be used by mixing a phosphorescent light emitting material and a fluorescent light emitting material (also referred to as a fluorescent dopant or a fluorescent compound) in the same light emitting layer. It is preferable that the light emitting layer contains a host compound (also referred to as a light emitting host or the like) and a light emitting material (also referred to as a light emitting dopant compound) and emits light from the light emitting material.

<Host compound>
As the host compound contained in the light emitting layer, a compound having a phosphorescent quantum yield of less than 0.1 at room temperature (25 ° C.) is preferable. Further, the phosphorus photon yield is preferably less than 0.01. Further, among the compounds contained in the light emitting layer, the volume ratio in the layer is preferably 50% or more.

As the host compound, a known host compound may be used alone, or a plurality of kinds of host compounds may be used. By using a plurality of types of host compounds, it is possible to adjust the transfer of electric charges, and it is possible to improve the efficiency of the organic electroluminescent device. Further, by using a plurality of kinds of light emitting materials described later, it is possible to mix different light emission, and thereby an arbitrary light emission color can be obtained.

The host compound used for the light emitting layer may be a conventionally known low molecular weight compound or a high molecular weight compound having a repeating unit, and a low molecular weight compound having a polymerizable group such as a vinyl group or an epoxy group (vapor deposition polymerizable light emitting host). ) May be.

Examples of the host compound applicable to the present invention include Japanese Patent Application Laid-Open No. 2001-257076, Japanese Patent Application Laid-Open No. 2001-357977, Japanese Patent Application Laid-Open No. 2002-8860, Japanese Patent Application Laid-Open No. 2002-43056, Japanese Patent Application Laid-Open No. 2002-105445, and Japanese Patent Application Laid-Open No. 2002-352957, 2002-231453, 2002-234888, 2002-260861, 2002-305083, US Patent Application Publication No. 2005/0112407, US Patent Application Publication 2009/0030202, International Publication No. 2001/039234, International Publication No. 2008/056746, International Publication No. 2005/0890225, International Publication No. 2007/063754, International Publication No. 2005/030900, International Publication No. Examples thereof include the compounds described in No. 2009/086028, International Publication No. 2012/0293947, Japanese Patent Application Laid-Open No. 2007-254297, European Patent No. 2034538 and the like.

<Luminescent material>
Examples of the light emitting material that can be used in the present invention include a phosphorescent compound (also referred to as a phosphorescent compound, a phosphorescent material or a phosphorescent dopant) and a phosphorescent compound (also referred to as a fluorescent compound or a phosphorescent material). However, it is particularly preferable to use a phosphorescent luminescent compound from the viewpoint of obtaining high luminescence efficiency.

<Phosphorescent compound>
The phosphorescent compound is a compound in which light emission from the excited triplet is observed, specifically, a compound that emits phosphorescent light at room temperature (25 ° C.), and the phosphorescent quantum yield is 0 at 25 ° C. It is defined as a compound of 0.01 or more, but a preferable phosphorescence quantum yield is 0.1 or more.

The phosphorus photon yield can be measured by the method described on page 398 (1992 edition, Maruzen) of Spectroscopy II of the 4th Edition Experimental Chemistry Course 7. The phosphorescence quantum yield in a solution can be measured using various solvents, but when the phosphorescence luminescent compound is used in the present invention, the phosphorescence quantum yield is 0.01 or more in any of any solvents. Should be achieved.

The phosphorus light emitting compound can be appropriately selected from known compounds used for the light emitting layer of a general organic EL element, and preferably contains a metal of Group 8 to 10 in the periodic table of the element. It is a complex-based compound, more preferably an iridium compound, an osmium compound, a platinum compound (platinum complex-based compound) or a rare earth complex, and the most preferable is an iridium compound.

In the present invention, at least one light emitting layer may contain two or more kinds of phosphorescent light emitting compounds, and the concentration ratio of the phosphorescent light emitting compound in the light emitting layer changes in the thickness direction of the light emitting layer. It may be in the above mode.

Specific examples of known phosphorescent compounds that can be used in the present invention include compounds described in the following documents.

Nature 395, 151 (1998), Appl. Phys. Let. 78, 1622 (2001), Adv. Mater. 19,739 (2007), Chem. Mater. 17, 3532 (2005), Adv. Mater. 17, 1059 (2005), International Publication No. 2009/100991, International Publication No. 2008/101842, International Publication No. 2003/040257, US Patent Application Publication No. 2006/835469, US Patent Application Publication No. 2006 / Examples thereof include the compounds described in US Patent Application Publication No. 0202194, US Patent Application Publication No. 2007/0087321, US Patent Application Publication No. 2005/0244673, and the like.

In addition, Inorg. Chem. 40,1704 (2001), Chem. Mater. 16, 2480 (2004), Adv. Mater. 16, 2003 (2004), Angew. Chem. lnt. Ed. 2006, 45, 7800, Appl. Phys. Let. 86,153505 (2005), Chem. Let. 34,592 (2005), Chem. Commun. 2906 (2005), Inorg. Chem. 42,1248 (2003), International Publication No. 2009/050290, International Publication No. 2009/000673, US Patent No. 73322232, US Patent Application Publication No. 2009/00397776, US Patent No. 6688266, USA Japanese Patent Application Publication No. 2006/0008670, US Patent Application Publication No. 2008/0015355, US Patent Application Publication No. 7396598, US Patent Application Publication No. 2003/01386657, US Patent No. 70090928. Etc. may be mentioned.

In addition, Angew. Chem. lnt. Ed. 47, 1 (2008), Chem. Mater. 18, 5119 (2006), Inorg. Chem. 46,4308 (2007), Organometallics 23,3745 (2004), Apple. Phys. Let. 74,1361 (1999), International Publication No. 2006/056418, International Publication No. 2005/123873, International Publication No. 2005/123873, International Publication No. 2006/082742, US Patent Application Publication No. 2005/0260441. , U.S. Patent No. 7534505, U.S. Patent Application Publication No. 2007/0190359, U.S. Patent No. 7338722, U.S. Patent No. 7279704, U.S. Patent Application Publication No. 2006/103874, etc. The described compounds can also be mentioned.

Furthermore, International Publication No. 2005/076380, International Publication No. 2008/140115, International Publication No. 2011/134013, International Publication No. 2010/086089, International Publication No. 2012/20327, International Publication No. 2011/051404 , International Publication No. 2011/073149, JP-A-2009-114086, JP-A-2003-81988, JP-A-2002-363552, and the like can also be mentioned.

In the present invention, preferred phosphorescent compounds include organic metal complexes having Ir as the central metal. More preferably, a complex containing at least one coordination mode of a metal-carbon bond, a metal-nitrogen bond, a metal-oxygen bond, and a metal-sulfur bond is preferred.

The phosphorescent compound (also referred to as a phosphorescent metal complex) described above is described in, for example, Organic Letter, vol3, No. 16, 2579-2581 (2001), Inorganic Chemistry, Vol. 30, No. 8, pp. 1685-1687 (1991), J. Mol. Am. Chem. Soc. , 123, 4304 (2001), Inorganic Chemistry, 40, 7, 1704-1711 (2001), Inorganic Chemistry, 41, 12, 3055-3066 (2002). , New Journal of Chemistry. , Vol. 26, pp. 1171 (2002), European Journal of Organic Chemistry, Vol. 4, pp. 695-709 (2004), and the methods disclosed in the references described in these documents. Can be synthesized by applying.

<Fluorescent luminescent compound>
Fluorescent compounds include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes, perylene dyes, and stylbens. Examples thereof include system dyes, polythiophene dyes, rare earth complex phosphors and the like.

(Other organic functional layers)
Next, each layer constituting the organic functional layer unit will be described in the order of a charge injection layer, a hole transport layer, an electron transport layer, and a blocking layer.

<Charge injection layer>
The charge injection layer is a layer provided between the electrode and the light emitting layer in order to reduce the driving voltage and improve the light emitting brightness. The details are described in Volume 2, Chapter 2, "Electrode Materials" (pages 123 to 166) of "S Co., Ltd.", and there are a hole injection layer and an electron injection layer.

The charge injection layer is generally present between the anode and the light emitting layer or the hole transport layer in the case of a hole injection layer, and between the cathode and the light emitting layer or the electron transport layer in the case of an electron injection layer. However, the present invention is characterized in that a charge injection layer is arranged adjacent to the transparent electrode. When used in an intermediate electrode, at least one of the adjacent electron injection layer and hole injection layer may satisfy the requirements of the present invention.

The hole injection layer is a layer arranged adjacent to the anode, which is a transparent electrode, in order to reduce the driving voltage and improve the emission brightness. (Published by TS) ”, Volume 2, Chapter 2,“ Electrode Materials ”(pages 123-166).

The details of the hole injection layer are described in JP-A-9-45479, 9-2660062, 8-288609, etc., and these compounds can be used for the hole injection layer. can.

Further, hexaazatriphenylene derivatives as described in JP-A-2003-591432 and JP-A-2006-135145 can also be used as the hole transport material in the same manner.

The electron injection layer is a layer provided between the cathode and the light emitting layer in order to reduce the driving voltage and improve the emission brightness, and when the cathode is composed of the transparent electrode according to the present invention, the electron injection layer is concerned. "Organic EL element and its forefront of industrialization (published by NTS Co., Ltd., November 30, 1998)", Volume 2, Chapter 2, "Electrode Material" (pages 123-166), which is provided adjacent to the transparent electrode. ) Is described in detail.

The details of the electron injection layer are also described in JP-A-6-325871, Japanese Patent Laid-Open No. 9-17574, Japanese Patent Application Laid-Open No. 10-74586, etc., and the materials described in these are described in the electron injection layer. It can be preferably used. The electron injection layer is preferably a very thin film, and the layer thickness is preferably in the range of 1 nm to 10 μm, although it depends on the constituent materials.

<Hole transport layer>
The hole transport layer is made of a hole transport material having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer also have a function of a hole transport layer. The hole transport layer may be provided as a single layer or a plurality of layers.

The hole transport material has any of hole injection or transport and electron barrier property, and may be either an organic substance or an inorganic substance.

As the hole transport material, the above-mentioned ones can be used, but porphyrin compounds, aromatic tertiary amine compounds and styrylamine compounds can be used, and in particular, aromatic tertiary amine compounds can be used. preferable.

The hole transport layer is a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an inkjet method, and an LB method (Langmuir Blodgett method). Therefore, it can be formed by thinning the film. The thickness of the hole transport layer is not particularly limited, but is usually in the range of about 5 nm to 5 μm, preferably in the range of 5 to 200 nm. The hole transport layer may have a one-layer structure composed of one kind or two or more kinds of the above materials.

Further, the p property can be enhanced by doping the material of the hole transport layer with impurities. Examples thereof include JP-A-4-297076, JP-A-2000-196140, JP-A-2001-102175 and J. Mol. Apple. Phys. , 95, 5773 (2004) and the like.

As described above, it is preferable to increase the p property of the hole transport layer because a device having lower power consumption can be manufactured.

<Electron transport layer>
The electron transport layer is composed of a material having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. The electron transport layer can be provided as a single-layer structure or a multi-layer laminated structure.

In the electron transport layer having a single layer structure and the electron transport layer having a laminated structure, as the electron transport material (also serving as a hole blocking material) constituting the layer portion adjacent to the light emitting layer, the electrons injected from the cathode are used as the light emitting layer. It suffices to have a function to transmit. As such a material, any of conventionally known compounds can be selected and used. For example, a nitro-substituted fluorene derivative, a diphenylquinone derivative, a thiopyrandioxide derivative, a carbodiimide, a freolenidene methane derivative, anthracinodimethane, an anthrone derivative, an oxadiazole derivative and the like can be mentioned. Further, among the above oxadiazole derivatives, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is replaced with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron-withdrawing group can also be used as a material for the electron transport layer. can. Further, a polymer material in which these materials are introduced into a polymer chain or a polymer material in which these materials are used as a polymer main chain can also be used.

Also, metal complexes of 8-quinolinol derivatives, such as tris (8-quinolinol) aluminum (abbreviation: Alq ₃ ), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-). Kinolinol) aluminum, tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (abbreviation: Znq), etc. and the central metal of these metal complexes A metal complex replaced with In, Mg, Cu, Ca, Sn, Ga or Pb can also be used as a material for the electron transport layer.

The electron transport layer can be formed by thinning the material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an inkjet method, and an LB method. The thickness of the electron transport layer is not particularly limited, but is usually in the range of about 5 nm to 5 μm, preferably in the range of 5 to 200 nm. The electron transport layer may have a single structure composed of one kind or two or more kinds of the above materials.

<blocking layer>
Examples of the blocking layer include a hole blocking layer and an electron blocking layer, which are layers provided as needed in addition to the constituent layers of the organic functional layer unit 3 described above. For example, it is described in JP-A No. 11-204258, JP-A-11-204359, and page 237 of "Organic EL element and its forefront of industrialization (published by NTS Co., Ltd., November 30, 1998)". Examples include a hole blocking (hole block) layer.

The hole blocking layer has a function of an electron transporting layer in a broad sense. The hole blocking layer is made of a hole blocking material having a function of transporting electrons and a significantly small ability to transport holes, and recoupling electrons and holes by blocking holes while transporting electrons. The probability can be improved. Further, the structure of the electron transport layer can be used as a hole blocking layer, if necessary. The hole blocking layer is preferably provided adjacent to the light emitting layer.

On the other hand, the electron blocking layer has a function of a hole transport layer in a broad sense. The electron blocking layer is made of a material that has a function of transporting holes and has a significantly small ability to transport electrons. By blocking electrons while transporting holes, the probability of recombination between electrons and holes is improved. Can be made to. Further, the structure of the hole transport layer can be used as an electron blocking layer, if necessary. The layer thickness of the hole blocking layer applied to the present invention is preferably in the range of 3 to 100 nm, and more preferably in the range of 5 to 30 nm.

The method for forming the organic functional layer according to the present invention is not particularly limited, and conventionally known methods such as a vacuum vapor deposition method and a wet method (also referred to as a wet process) can be used.

The wet method includes spin coating method, casting method, dispenser method, inkjet printing method, printing method, die coating method, blade coating method, roll coating method, spray coating method, curtain coating method, and LB method (Langmuir-Bloget method). However, from the viewpoint of easy to obtain a uniform thin film and high productivity, a method having high suitability for a roll-to-roll method such as a dispenser method, a die coating method, an inkjet printing method, and a spray coating method is preferable. Above all, the inkjet printing method is preferable from the viewpoint of ease and accuracy in coating.

For example, the inkjet heads applicable to the present invention include, for example, Japanese Patent Application Laid-Open No. 2012-140017, Japanese Patent Application Laid-Open No. 2013-010227, Japanese Patent Application Laid-Open No. 2014-058171, JP-A-2014-097644, and JP-A-2015. 142979, 2015-142980, 2016-002675, 2016-002682, 2016-107401, 2017-109476, 2017-177626. An inkjet head having the configuration described in the publication and a printing method can be appropriately selected and applied.

The coating liquid used in the wet method may be a solution in which the material forming the organic functional layer is uniformly dissolved in the liquid medium, or a dispersion liquid in which the material is dispersed in the liquid medium as a solid content. As a dispersion method, it can be dispersed by a dispersion method such as ultrasonic wave, high shear force dispersion or media dispersion.

The liquid medium is not particularly limited, and is, for example, a halogen-based solvent such as chloroform, carbon tetrachloride, dichloromethane, 1,2-dichloroethane, dichlorobenzene or dichlorohexanone, acetone, methylethylketone, diethylketone, methylisobutylketone, n-. Ketone solvents such as propylmethylketone and cyclohexanone, aromatic solvents such as benzene, toluene, xylene, mesitylene and cyclohexylbenzene, aliphatic solvents such as cyclohexane, decalin and dodecane, ethyl acetate, n-propyl acetate, n acetate. -Ester solvents such as butyl, methyl propionate, ethyl propionate, γ-butyrolactone, diethyl carbonate, ether solvents such as tetrahydrofuran and dioxane, amide solvents such as dimethylformamide and dimethylacetamide, methanol, ethanol and 1-butanol. , Alcohol-based solvent such as ethylene glycol, nitrile-based solvent such as acetonitrile and propionitrile, dimethyl sulfoxide, water or a mixed solution medium thereof and the like.

The boiling point of these liquid media is preferably a boiling point lower than the temperature of the drying treatment from the viewpoint of quickly drying the liquid medium, specifically in the range of 60 to 200 ° C, more preferably 80 to 180 ° C. Is within the range of.

The coating liquid contains a surfactant for the purpose of controlling the coating range and suppressing the liquid flow associated with the surface tension gradient after coating (for example, the liquid flow that causes a phenomenon called coffee ring). Can be done.

Examples of the surfactant include anionic or nonionic surfactants from the viewpoint of the influence of water contained in the solvent, leveling property, wettability to the substrate f1 and the like. Specifically, the surfactants listed in International Publication No. 08/146681, JP-A-2-41308, etc., such as fluorine-containing activators, can be used.

Similar to the film thickness, the viscosity of the coating film can be appropriately selected depending on the function required as the organic functional layer and the solubility or dispersibility of the organic material. Specifically, for example, 0.3 to 100 mPa. -Can be selected within the range of s.

The film thickness of the coating film can be appropriately selected depending on the function required as the organic functional layer and the solubility or dispersibility of the organic material, and specifically, can be selected within the range of, for example, 1 to 90 μm. ..

When a vapor deposition method is used for film formation, the vapor deposition conditions vary depending on the type of compound used, but generally, the boat heating temperature is 50 to 450 ° C., the degree of vacuum is 1 × 10 ^-6 to 1 × 10 ^-2 Pa, It is desirable to appropriately select the vapor deposition rate within the range of 0.01 to 50 nm / sec, the support substrate temperature of -50 to 300 ° C., and the thickness of 0.1 nm to 5 μm, preferably 5 to 200 nm.

It is preferable to form the organic functional layer consistently from the hole injection layer to the cathode by one vacuuming, but it may be taken out in the middle and a different film forming method may be applied. In that case, it is preferable to carry out the work in a dry inert gas atmosphere.

[4] Sealing member As a sealing means used for sealing an organic EL element, for example, a method of adhering a flexible sealing member, a cathode and a transparent substrate with a sealing adhesive can be mentioned. can.

The sealing member may be arranged so as to cover the display area of the organic EL element, and may be intaglio-shaped or flat-plate-shaped. Further, transparency and electrical insulation are not particularly limited.

Specific examples thereof include a thin film glass plate having flexibility, a polymer plate, a film, and a metal film (metal foil). Examples of the glass plate include soda-lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz. Examples of the polymer plate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, polysulfone and the like. Examples of the metal film include one or more metals or alloys selected from the group consisting of stainless steel, iron, copper, aluminum, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicon, germanium and tantalum.

In the present invention, a polymer film and a metal film can be preferably used as the sealing member from the viewpoint that the organic EL element can be thinned. Further, the polymer film has a water vapor permeability of 1 × 10 ^-3 g / m ² . It is preferably 24 hours or less, and further, the oxygen permeability measured by a method according to JIS K 7126-1987 is 1 × 10 ^-3 ml / ^m 2.24 h · atm (1 atm is 1.01325 ×. It is preferably ¹⁰⁵ Pa) or less, and the water vapor permeability at a temperature of 25 ± 0.5 ° C. and a relative humidity of 90 ± ² % RH is preferably 1 × 10 ^-3 g / m 2.24 h or less. These can be achieved by providing the gas barrier layer having a high shielding ability against the above-mentioned water and oxygen.

Specific examples of the adhesive used for adhering the organic EL element and the encapsulant include an acrylic acid-based oligomer, a photocurable and thermosetting adhesive having a reactive vinyl group of a methacrylic acid-based oligomer, and a 2-cyanoacrylic acid ester. Examples thereof include moisture-curable adhesives such as. In addition, heat and chemical curing type (two-component mixture) such as epoxy type can be mentioned. Further, hot melt type polyamide, polyester and polyolefin can be mentioned. Further, a cation-curable type ultraviolet-curable epoxy resin adhesive can be mentioned.

Since the organic EL element may be deteriorated by heat treatment, it is preferable that the organic EL element can be adhesively cured from room temperature (25 ° C.) to 130 ° C. Further, the desiccant may be dispersed in the adhesive. A commercially available dispenser may be used to apply the adhesive to the encapsulating substrate, or printing may be performed as in screen printing.

In the gas phase and liquid phase, an inert gas such as nitrogen or argon or an inert liquid such as fluorinated hydrocarbon or silicon oil is injected into the gap between the sealing member and the display region (light emitting region) of the organic EL element. You can also do it. Further, the gap between the sealing member and the display region of the organic EL element can be evacuated, or the hygroscopic compound can be sealed in the gap.

Further, it is also possible to provide a sealing film on the transparent substrate in a state where the light emitting functional layer unit in the organic EL element is completely covered and the anode and the terminal portion of the cathode in the organic EL element are exposed.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. Although the display of "parts" or "%" is used in the examples, it represents "parts by mass" or "% by mass" unless otherwise specified.
[Preparation method of metal particle dispersion]
<Preparation of metal particle dispersion liquid 101>
100 mL of a 1000 mM silver nitrate aqueous solution was taken in a beaker. In another beaker, 3 g of a non-volatile organic substance (Disperbic 190 (trade name): described as BYK190 in the table, manufactured by Big Chemie, 40% aqueous solution) was taken as a dispersant, and 100 g of pure water was added thereto.

To a beaker containing an aqueous silver nitrate solution, 11 g of a Disperbic 190 aqueous solution prepared in another beaker was added.

After sufficiently stirring, 15 g of triethanolamine was added, and the mixture was stirred at 60 ° C. for 3 hours.

Centrifugal purification was performed 3 times. Pure water was added to the obtained silver particles to make a total of 50 g, which was ultrasonically dispersed to obtain a metal particle dispersion liquid 101.

When 50 g of the metal particle dispersion 101 was dried at 250 ° C. for 30 minutes, 10 g of a solid was obtained. When this solid was heated to 500 ° C. using a thermogravimetric / differential thermal analyzer, the mass decreased by 0.8%.

Assuming that water, which is a solvent, evaporates when heated to 250 ° C, and the non-volatile organic substance as a dispersant decomposes when heated to 500 ° C, the mass ratio of the content of the non-volatile organic substance to the metal content is obtained. , 1: 0.008.

<Preparation of metal particle coating liquid 101>
To 10 g of the metal particle dispersion liquid 101, 1.1 g of pure water and 2.3 g of 2-propanol were added and stirred well to obtain a metal particle coating liquid 101. The mass ratio of the solvent in this coating liquid is 2-propanol 0.2 with respect to water 0.8. The total concentration of the metal particles and the non-volatile organic substance is 15% by mass.

The metal particle coating liquid 101 was diluted 100-fold with water, and the average particle size was determined using a particle size measuring device (Zetasizer Nano S, manufactured by Malvern Instruments) by a dynamic light scattering method. The average particle size was 100 nm.

[Manufacturing of organic EL element 101]
(Preparation of base material)
First, a silicon oxide film was formed with a thickness of 300 nm on the entire surface of the polyethylene naphthalate film (manufactured by Teijin Film Solutions Co., Ltd.) on the side where the anode is formed under the following film forming conditions (plasma CVD conditions).
(Plasma CVD conditions)
Supply amount of raw material gas (HMDSO): 50 sccm (Standard Cubic Centimeter per Minute)
Oxygen gas (O ₂ ) supply: 500 sccm
Vacuum degree in vacuum chamber: 3Pa
Power applied from plasma generation power supply: 1.2kW
Frequency of power supply for plasma generation: 80kHz
Film transport speed: 0.5 m / min

(Formation of anode)
An ITO (indium tin oxide) having a thickness of 120 nm was formed on the substrate by a sputtering method and patterned by a photolithography method to form an anode. The pattern was set so that the area of the light emitting region was 5 cm × 5 cm.

(Formation of hole injection layer)
The substrate on which the anode was formed was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes. Then, on the substrate on which the anode is formed, a dispersion of poly (3,4-ethylenedioxythiophene) / polystyrene sulfonate (PEDOT / PSS) prepared in the same manner as in Example 16 of Japanese Patent No. 45097787 is isopropyl alcohol. The 2% by mass solution diluted in 1 was applied by an inkjet printing method and dried at 80 ° C. for 5 minutes to form a hole injection layer having a layer thickness of 40 nm.

(Formation of hole transport layer)
Next, the substrate on which the hole injection layer was formed was transferred to a nitrogen atmosphere using nitrogen gas (grade G1), and coated by an inkjet printing method using a coating liquid for forming a hole transport layer having the following composition. , It was dried at 150 ° C. for 30 minutes to form a hole transport layer having a layer thickness of 30 nm.
<Coating liquid for forming a hole transport layer>
Hole transport material HT-3 (weight average molecular weight Mw = 80000) 10 parts by mass Para (p) -xylene 3000 parts by mass (formation of light emitting layer)
Next, the substrate on which the hole transport layer was formed was applied by an inkjet printing method using a coating liquid for forming a light emitting layer having the following composition, and dried at 130 ° C. for 30 minutes to form a light emitting layer having a layer thickness of 50 nm. bottom.

<Coating liquid for forming a light emitting layer>
Host compound H-4 9 parts by mass Metal complex CD-2 1 part by mass Metal complex CD-1 0.1 part by mass Normal butyl acetate 2000 parts by mass (formation of electron transport layer)
Next, the coating liquid for forming an electron transport layer having the following composition was applied by an inkjet printing method and dried at 120 ° C. for 30 minutes to form an electron transport layer having a layer thickness of 30 nm.
<Coating liquid for forming an electron transport layer>
ET-1 6 parts by mass 2,2,3,3-tetrafluoro-1-propanol 2000 parts by mass (formation of electron injection layer)
Subsequently, the substrate was attached to the vacuum deposition apparatus without exposure to the atmosphere. In addition, a molybdenum resistance heating boat containing sodium fluoride and potassium fluoride was attached to a vacuum vapor deposition apparatus, and the vacuum tank was depressurized to 4 × ^10-5 Pa. Then, the boat was energized and heated, and sodium fluoride was deposited on the electron transport layer at 0.02 nm / sec to form a thin film having a film thickness of 1 nm. Similarly, potassium fluoride was deposited on a sodium fluoride thin film at 0.02 nm / sec to form an electron-injected layer having a layer thickness of 1.5 nm.

The compounds used are shown below.

(Cathode formation)
The metal particle coating liquid 101 was applied to a substrate having a film formed up to the electron injection layer using a dispenser to form a cathode. The amount of liquid and the coating speed were adjusted in advance so that the film thickness after drying would be 200 nm. After application, it was dried in a constant temperature bath at 120 ° C. for 30 minutes.

To measure the above film thickness, apply the coating liquid on a separately prepared glass substrate, peel off a part, and use Bruker's stylus profiling system Dektak to remove the step between the peeled part and the part where the film remains. Measured using.

(Formation of sealing layer)
A film (manufactured by Panac) in which an aluminum foil with a thickness of 20 μm and a pet film with a thickness of 100 μm are laminated has an oxygen permeability of 0.001 mL / ( ^m 2.24 h ・ atm) or less and a water vapor permeability of 0.001 g / (). A flexible gas barrier film having a gas barrier property of ^m 2.24 h) or less was used. A thermosetting liquid adhesive (epoxy resin) was formed as a sealing resin layer on the surface of the aluminum foil of this film to a thickness of 25 μm. Then, the gas barrier film provided with the sealing resin layer was superposed on the device produced up to the cathode produced. At this time, the sealing resin layer forming surface of the gas barrier film was continuously superposed on the sealing surface side of the organic EL element so that the ends of the anode and the cathode taking-out portions were exposed to the outside.

Next, the sample to which the gas barrier film was bonded was placed in a decompression device, pressed under a depressurization condition of 0.1 MPa at 90 ° C., and held for 5 minutes. Subsequently, the sample was returned to the atmospheric pressure environment and further heated at 90 ° C. for 30 minutes to cure the adhesive.

The sealing step is based on JIS B 9920 under atmospheric pressure and a nitrogen atmosphere with a water content of 1 ppm or less, the measured cleanliness is class 100, the dew point temperature is -80 ° C or less, and the oxygen concentration is 0.8 volume. It was carried out at an atmospheric pressure of ppm or less.

The organic EL element 101 was manufactured by the above steps.

[Manufacturing of organic EL element 102]
<Preparation of metal particle coating liquid 102>
A non-volatile organic substance (Dispervic 190 (trade name), manufactured by Big Chemie, 40% aqueous solution) was additionally added to the metal particle coating liquid 101 to make it non-volatile with respect to the metal content as shown in Table I. The mass ratio of the organic matter content was found to be 1: 0.01.

Specifically, 0.1 g of a non-volatile organic substance (Disperbic 190 (trade name), manufactured by Big Chemie, 40% aqueous solution) was added to 101, 100 g of the metal particle coating liquid (0.04 g as a solid content). ..

Further, pure water is used so that the content of the non-volatile organic substance with respect to the metal content is the mass ratio shown in Table I, and the total concentration of the metal particles and the non-volatile organic substance is 15%. 2-Propanol was added to obtain a metal particle coating liquid 102.

This coating liquid was applied in the same manner as the organic EL element 101 to produce an organic EL element 102.

[Preparation of metal particle coating liquids 103 to 106 and production of organic EL elements 103 to 106]
Similarly, the metal particle coating liquids 103 to 106 shown in Table I were prepared by changing the metal content and the non-volatile organic substance content, respectively, and the organic EL devices 103 to 106 were manufactured using the metal particle coating liquids 103 to 106. ..

[Preparation method of metal particle dispersion]
<Metal particle dispersion 201>
100 mL of a 1000 mM silver nitrate aqueous solution was taken in a beaker. In another beaker, 3 g of a non-volatile organic substance (Disperbic 190 (trade name), manufactured by Big Chemie, 40% aqueous solution) was taken as a dispersant, and 100 g of pure water was added thereto.

To a beaker containing an aqueous silver nitrate solution, 21 g of a Disperbic 190 aqueous solution prepared in another beaker was added.

After sufficiently stirring, 15 g of triethanolamine was added, and the mixture was stirred at 60 ° C. for 3 hours.
Centrifugal purification was performed 3 times. Pure water was added to the obtained silver particles to make a total of 50 g, which was ultrasonically dispersed to obtain a metal particle dispersion liquid 201.

Similar to the metal particle dispersion 101, the mass ratio of the content of the non-volatile organic substance to the content of the metal was found to be 1: 0.015.

<Metal particle coating liquid 201>
A non-volatile organic substance (Disperbic 190 (trade name), manufactured by Big Chemie, 40% aqueous solution) was additionally added to the metal particle dispersion 201 to bring the concentration shown in Table I.

Further, pure water and 2 so that the content of the non-volatile organic substance with respect to the metal content is the mass ratio shown in Table I, and the total concentration of the metal particles and the non-volatile organic substance is 15%. -Propanol was added to obtain a metal particle coating liquid 102.

The metal particle coating liquid 201 was diluted 100-fold with water, and the average particle size was determined using a particle size measuring device (Zetasizer Nano S, manufactured by Malvern Instruments) by a dynamic light scattering method. The average particle size was 60 nm.

<Preparation of metal particle dispersion liquid 202>
100 ml of a 1000 mM silver nitrate aqueous solution was placed in a beaker. In another beaker, 6 g of a non-volatile organic substance (Disperbic 190 (trade name), manufactured by Big Chemie, 40% aqueous solution) was taken as a dispersant, and 200 g of pure water was added thereto.

To the beaker containing the silver nitrate aqueous solution, 42 g of the Disperbic 190 aqueous solution prepared in another beaker was added.

After sufficiently stirring, 15 g of triethanolamine was added, and the mixture was stirred at 60 ° C. for 3 hours. Then, centrifugation and purification were performed three times. Pure water was added to the obtained silver particles to make a total of 50 g, which was ultrasonically dispersed to obtain a metal particle dispersion liquid 202.

Similar to the metal particle dispersion 101, the mass ratio of the content of the non-volatile organic substance to the content of the metal was found to be 1: 0.03.

<Preparation of metal particle coating liquid 202>
The metal particle coating liquid 202 shown in Table I was prepared in the same manner as in the preparation of the metal particle coating liquid 201. The particle size of the metal particles was 30 nm when the same measurement was performed.

[Manufacturing of organic EL elements 201 and 202]
The organic EL elements 201 and 202 were produced using the metal particle coating liquids 201 and 202 in the same manner as in the production of the organic EL element 101.

[Preparation method of metal particle dispersion]
<Preparation of Metal Particle Dispersion Liquid 301>
13 g of a non-volatile organic substance (dextrin No. 3 manufactured by Roasted Dextrin Nissho Chemical Co., Ltd.) and 115 g of pure water were added to the beaker as a dispersant, and the mixture was stirred and dissolved for about 30 minutes. Then, 31 g of silver nitrate was added, and the mixture was stirred and dissolved for about 30 minutes. This liquid was cooled to about 5 ° C. in an ice bath, a liquid at 10 ° C. in which 15 g of potassium hydroxide was dissolved in 20 g of pure water was added, and the mixture was stirred in an ice bath for 1 hour.

Centrifugal purification was performed 3 times. Pure water was added to the obtained silver particles to make a total of 50 g, which was ultrasonically dispersed to obtain a metal particle dispersion liquid 301.

Similar to the metal particle dispersion 101, the mass ratio of the content of the non-volatile organic substance to the content of the metal was found to be 1: 0.03.

In addition, qualitative analysis of non-volatile organic matter by NMR and infrared spectroscopy revealed a carboxylic acid component. It could be presumed that silver was reduced by the conversion of dextrin to alginic acid oxide.

<Preparation of metal particle coating liquid 301>
The metal particle coating liquid 301 was prepared in the same manner as the preparation of the metal particle coating liquid 202. However, the mass of the non-volatile organic matter was adjusted with an aqueous solution of potassium alginate instead of dextrin.

<Preparation of metal particle dispersion liquid 302>
61 g of polyethyleneimine (manufactured by Sigma-Aldrich), a non-volatile organic substance, was put into a beaker as a dispersant, and 219 g of pure water was put into the beaker. The mixture was heated to 90 ° C. and stirred.

31 g of silver nitrate was dissolved in 365 g of water, polyethyleneimine was added, and the mixture was added to the beaker. Further, 13 g of ascorbic acid was dissolved in 73 g of water and added. Then, the mixture was stirred at 90 ° C. for 30 minutes. Centrifugal purification was performed 3 times. Pure water was added to the obtained silver particles to make a total of 50 g, and ultrasonically dispersed to obtain a metal particle dispersion liquid 302.

Similar to the metal particle dispersion 101, the mass ratio of the content of the non-volatile organic substance to the content of the metal was found to be 1: 0.03.

<Preparation of metal particle coating liquid 302>
The metal particle coating liquid 302 was prepared in the same manner as the preparation of the metal particle coating liquid 301. Polyethylenimine was added as a non-volatile organic substance to obtain a metal particle coating liquid 302.

<Preparation of metal particle coating liquids 303 and 304>
Similar to the metal particle coating liquid 302, the metal particle coating liquids 303 and 304 were prepared by changing only the solvent composition shown in Table II.

<Preparation of metal particle dispersion liquid 305 and metal particle coating liquid 305>
In the preparation of the metal particle dispersion liquid 202, the metal particle dispersion liquid 305 and the metal particle coating liquid 305 were prepared in the same manner except that the silver nitrate aqueous solution was replaced with the gold chloride aqueous solution.

<Metal particle dispersion liquid 306 and metal particle coating liquid 306>
In the preparation of the metal particle dispersion liquid 202, the metal particle dispersion liquid 306 and the metal particle coating liquid 306 were obtained in the same manner except that the silver nitrate aqueous solution was replaced with the palladium chloride aqueous solution.

[Manufacturing of organic EL elements 301 to 306]
Similar to the production of the organic EL element 101, the organic EL elements 301 to 306 were produced by using the metal particle coating liquids 301 to 306.

[Manufacturing of organic EL element 401]
In the production of the organic EL element 301, the organic EL element 401 is similarly applied except that the metal particle coating liquid is applied, warm air at 120 ° C. is blown for 5 minutes, and then the organic EL element 301 is dried in a constant temperature bath at 120 ° C. for 30 minutes. Was produced.

[Manufacturing of organic device 402]
In the production of the organic EL element 301, after applying the metal particle coating liquid, irradiation with infrared rays for 5 minutes under the same conditions as IR-2 of Patent No. 6319090, paragraph [805], and then 30 in a constant temperature bath at 120 ° C. The organic EL element 402 was produced in the same manner except that it was dried for a minute.

[Preparation method of metal particle coating liquid]
<Preparation of metal particle coating liquid 501A>
A metal particle coating liquid 501A coating liquid was obtained by adding only a solvent to the metal particle dispersion liquid 301 without adding alginic acid.

[Manufacturing of organic EL element 501]
The metal particle dispersion 301 is applied so as to have a film thickness of 50 nm, dried in a constant temperature bath at 120 ° C. for 30 minutes, and then the metal particle coating solution 501A is applied so as to have a film thickness of 150 nm and is kept at a constant temperature of 120 ° C. The organic EL element 501 shown in Table III having a two-layered cathode was prepared by drying in a tank for 30 minutes.

≪Evaluation≫
(1) Measurement of mass ratio (B / A) of metal particles and non-volatile organic matter in the range of 10 nm in the thickness direction from the interface on the organic functional layer side of the electrode (K) using the organic EL element produced above. , NN-04T, an oblique cutting device manufactured by Daipla Wintes, was used to prepare a cross section of an organic EL element sample at an angle of 0.20 degrees.
The interface of the cut out section from the interface between the organic functional layer and the electrode is analyzed by composition analysis using a time-of-flight secondary ion mass spectrometer (TOF-SIMS: manufactured by Physical Electronics Co., Ltd.). The composition of the 10 nm portion was determined in the thickness direction.
In addition, a sample in which the mass ratio of metal particles and organic substances was changed was prepared in advance, and a calibration curve for converting the detection signal and the mass was prepared in a time-of-flight type secondary ion mass spectrometer.
Further, the mass ratio of the content of the metal particles and the non-volatile organic substance in the range of 10 nm in the thickness direction from the interface on the side opposite to the organic functional layer side was measured by the same method.
(2) Mass of water and organic solvent in an electrode composed of metal particles Separately from the above organic EL element, each metal particle coating liquid was applied onto a silicon wafer of 1 cm × 1 cm.

Each silicon wafer was measured with a thermal desorption analyzer manufactured by Electronic Science Co., Ltd.

The sample was heated to determine the mass of water and organic solvent (2-propanol, 1-ethoxy-2-propanol, water: 2-methoxyethanol) observed between 80 and 200 ° C. In advance, a calibration curve was obtained for the detection sensitivity of the thermal desorption analyzer and the mass of each solvent.

Further, the volume of the electrode made of metal particles was obtained from the thickness of the electrode made of metal particles and the area (1 cm × 1 cm) separately obtained, and the amount of water and the organic solvent per unit volume (mm ³ ) was obtained. ..

(2) Power efficiency (indicator of luminous efficiency)
A DC voltage / current source / monitor 6234 manufactured by ADC was used to pass a current of 30 A / m ² through the manufactured organic EL element, and the voltage at that time was measured.

In addition, the brightness was measured using a spectral radiance meter CS-2000 manufactured by Konica Minolta. The power efficiency was calculated based on the following formula.

(Brightness) x pi ÷ (current density x voltage) (lm / W)
The relative values are shown in Tables I to III with the power efficiency of the organic EL element 101 as 100.

(3) Drive life While passing a current of 100 A / m ² through the organic EL element, the brightness was intermittently measured using a spectral radiance meter CS-2000 manufactured by Konica Minolta. The drive life is defined as the time when the brightness is reduced to less than half from the initial brightness.

The relative values are shown in Tables I to III with the drive life of the organic EL element 101 as 100.

(4) Bending resistance Each organic EL element was wound around a cylinder having a diameter of 100 mm, stored in a constant temperature bath at 60 ° C. for 100 hours, and then the change in power efficiency before and after storage was measured. The larger the value, the better the bending resistance.

From Tables I to III, the organic EL element having the configuration of the present invention has low resistance and is excellent in adhesion between the organic functional layer and the electrode, so that it is excellent in bending resistance, luminous efficiency and drive life during high temperature storage. Is clear. Above all, it was found that by forming the electrode according to the present invention in a two-layer structure, it is possible to secure higher conductivity in addition to adhesion and improve the power efficiency and drive life of the organic EL element.

1 Cross section of diagonally cut sample 2 Substrate 3 Applicable electrode (K)
4 Organic functional layer 5 Other electrode 6 Interface EL organic EL element 10 Substrate 11 Gas barrier layer 12 Anode 13 First organic functional layer 14 Light emitting layer 15 Second organic functional layer 16 Organic functional layer unit 17 Cathode, electrode (K) )
18 Adhesive layer for encapsulation 19 Encapsulation substrate K1 First electrode layer K2 Second electrode layer h Emission point L Emission light

Claims (10)

An organic electroluminescence device having at least a substrate and an organic functional layer sandwiched between an anode and a cathode.
The electrode (K) of at least one of the anode and the cathode is a metal thin film layer containing metal particles and a non-volatile organic substance.
The mass ratio of the total content (B) of the non-volatile organic substance to the total content (A) of the metal particles in the portion of the electrode (K) in the range of 10 nm in the thickness direction from the interface on the organic functional layer side. An organic electroluminescence element having (B / A) in the range of 0.01 to 0.10. The organic electroluminescence device according to claim 1, wherein the electrode (K) is an electrode on the side far from the substrate with respect to the organic functional layer. The mass ratio (B / A) is in the range of 0.01 to 0.05 in the portion of the electrode (K) in the range of 10 nm in the thickness direction from the interface opposite to the organic functional layer side. The organic electroluminescence device according to claim 1 or 2, characterized in that. The organic electroluminescence device according to any one of claims 1 to 3, wherein the electrode (K) contains water in the range of 20 to 300 μg per 1 mm ³ . The organic electroluminescence device according to any one of claims 1 to 4, wherein the electrode (K) contains an organic solvent in the range of 4 to 100 μg per 1 mm ³ . The organic electroluminescence device according to any one of claims 1 to 5, wherein the metal of the metal particles is silver. The organic electroluminescence device according to any one of claims 1 to 6, wherein the substrate is a flexible substrate. A method for manufacturing an organic electroluminescence device according to any one of claims 1 to 7, wherein the organic electroluminescence device is manufactured.
A step of forming either one of the anode and the cathode and an organic functional layer on the substrate in this order.
A step of preparing a dispersion liquid containing the metal particles and the non-volatile organic substance, and
It comprises a step of applying the dispersion liquid on the organic functional layer and drying to form the electrode (K).
The organic electroluminescence is characterized in that the dispersion is prepared so that the mass ratio of the content of the non-volatile organic substance to the content of the metal is in the range of 1: 0.01 to 1: 0.10. Method of manufacturing the element. Further, the present invention comprises a step of forming the electrode (K) from the organic functional layer side in a two-layer structure of a first electrode layer (K1) and a second electrode layer (K2).
In the process
A dispersion is prepared so that the mass ratio of the content of the non-volatile organic substance to the content of the metal is in the range of 1: 0.01 to 1: 0.10, and the dispersion is used as the organic functional layer. It is applied and dried on top to form a first electrode layer (K1), then
A dispersion is prepared so that the mass ratio of the content of the non-volatile organic substance to the content of the metal is in the range of 1: 0.01 to 1: 0.05, and the dispersion is used as the first dispersion. The method for manufacturing an organic electroluminescence element according to claim 8, wherein a second electrode layer (K2) is formed by applying and drying on the electrode layer (K1). The step of applying the dispersion liquid by a dispenser or an inkjet printing method, and
The method for producing an organic electroluminescence device according to claim 8 or 9, wherein the applied dispersion liquid is dried and then fired.

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