JP2018110180A - Light-emitting layer forming composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel light-emitting layer forming composition, with which a light-emitting layer can be produced simply, easily, efficiently and industrially advantageously.SOLUTION: A light-emitting layer is obtained by: atomizing a raw material solution or forming the raw material solution into droplets (atomization/droplet formation step), the raw material solution containing a light-emitting layer forming composition which contains a metal complex and an oxygen atom-containing cyclic compound as a solvent; transporting obtained mist or droplets onto a substrate by carrier gas (transport step); and reacting the mist or droplets on the substrate to form a light-emitting layer on the substrate (film formation step).SELECTED DRAWING: None

Description

  The present invention comprises a hole transport layer and / or a light-emitting layer, and is used for forming a light-emitting layer in a method for producing an organic light-emitting element useful for an electronic device such as a display device or a lighting device. Relates to the composition. A light-emitting element (also referred to as an EL element) having a structure in which an anode, a cathode, and a light-emitting organic material (hereinafter referred to as an organic EL material) from which EL (Electro Luminescence 0) is obtained is sandwiched between them is formed on a substrate. The present invention relates to a light-emitting device (also referred to as an EL display device) and a method for manufacturing an electronic device having the light-emitting device as a display portion (display display or display monitor). The light emitting device is also referred to as OLED (Organic Light Emitting Diodes).

  In recent years, development of a light-emitting device (EL display device) using an EL element as a light-emitting element using the EL phenomenon of a light-emitting organic material has been advanced. Since the EL display device is a self-luminous type, it does not require a backlight like a liquid crystal display device, and further has a wide viewing angle. Therefore, it is promising as a display unit of a portable device used outdoors, for example.

  A hole transport layer and a light emitting layer are used for the EL element, and there are two types of EL display devices including the EL element, a passive type (simple matrix type) and an active type (active matrix type). There is a lot of development going on. In particular, active matrix EL display devices are currently attracting attention. In addition, low molecular organic EL materials and high molecular organic EL materials (polymer organic EL materials) have been studied as organic EL materials serving as a light emitting layer, which can be said to be the center of an EL element.

  Patent Document 1 discloses forming a light emitting layer or the like using a nozzle printing method. According to this method, an organic EL material made of a polymer can be formed with high throughput without positional deviation. However, heat treatment (baking or baking) in vacuum evaporates the organic solvent contained in the coating solution and forms a light emitting layer made of an organic EL material. Simplification of the process is considered as an issue. Further, the nozzle printing method has a problem that a light emitting layer or the like cannot be formed uniformly due to collision energy.

  Patent Document 2 describes that a hole transport layer and a light emitting layer are formed using vacuum deposition. However, the invention described in Patent Document 2 manufactures an organic light-emitting element that has high electron injection efficiency and can be driven at a low voltage by performing a specific process for forming the electron injection layer. In addition, the light emitting layer has not been particularly studied for its formation means, and there is a problem that a vacuum facility or the like is required, which is costly. Further, since productivity is not high in vacuum deposition, a method for forming a hole transport layer and a light emitting layer easily and simply has been desired.

JP 2001-189192 A JP 2007-188870 A

  An object of this invention is to provide the composition for light emitting layer formation which can form a light emitting layer simply and easily, efficiently and industrially advantageously.

As a result of intensive studies to achieve the above object, the inventors of the present invention simply formed a light emitting layer using a composition for forming a light emitting layer comprising a metal complex and a cyclic ester as a solvent. In addition, it has been found that a light emitting layer can be formed efficiently and industrially advantageously, and it has been found that such a composition for forming a light emitting layer can solve the above-mentioned conventional problems all at once.
Moreover, after obtaining the said knowledge, the present inventors repeated investigation further, and came to complete this invention.

That is, the present invention relates to the following inventions.
[1] A light emitting layer forming composition used for forming a light emitting layer, comprising a metal complex and an oxygen atom-containing cyclic compound as a solvent.
[2] The composition for forming a light emitting layer according to [1], wherein the metal complex has a quinoline skeleton or a benzoquinoline skeleton.
[3] The composition for forming a light emitting layer according to [1] or [2], wherein the metal complex is an aluminum quinolinol complex.
[4] The composition for forming a light emitting layer according to any one of [1] to [3], wherein the metal complex is Alq3.
[5] The composition for forming a light emitting layer according to any one of [1] to [4], wherein the oxygen atom-containing cyclic compound is a lactone or a lactam.
[6] The composition for forming a light emitting layer according to any one of [1] to [5], wherein the oxygen atom-containing cyclic compound is γ-butyrolactone.
[7] A method for producing a light emitting layer in which a light emitting layer is formed directly from a raw material solution on a substrate or via another layer, wherein the raw material solution is a light emitting device according to any one of [1] to [6]. The manufacturing method of the light emitting layer characterized by including the composition for layer formation.
[8] In forming the light emitting layer, the raw material solution is atomized or formed into droplets, and the resulting mist or droplets are conveyed onto the substrate with a carrier gas, and the mist or droplets react on the substrate. The method according to [7], wherein the production is performed by laminating a light emitting layer on the substrate.
[9] A light emitting layer produced by the production method according to [7] or [8].
[10] An organic light emitting device having at least an electrode, a hole transport layer, and a light emitting layer, wherein the light emitting layer is the light emitting layer according to [9].
[11] An electronic device including the organic light-emitting element according to [10] or a component thereof.
[12] A system comprising the electronic device according to [11] or a part thereof.

  According to the composition for forming a light emitting layer of the present invention, a light emitting layer can be formed easily and easily, efficiently and industrially advantageously.

It is a schematic block diagram of the film-forming apparatus (mist CVD apparatus) used in the Example. It is a typical schematic block diagram of the module containing the organic light emitting element of this embodiment. FIG. 3 is a plan view schematically showing a configuration of a drive circuit in the module of FIG. 2. It is a figure which shows the measurement result of the fluorescence spectrum of the laminated body obtained in the Example. It is a figure which shows the measurement result of the fluorescence spectrum of the laminated body obtained in the Example.

  The composition for forming a light-emitting layer of the present invention is a composition for forming a light-emitting layer used for forming a light-emitting layer, and includes a metal complex and an oxygen atom-containing cyclic compound as a solvent. To do.

  The metal complex can be used as a precursor of the light emitting layer, and is not particularly limited as long as it is a metal compound having a metal-carbon bond or a metal complex having a coordination bond. The metal in the metal complex is not particularly limited, but is preferably beryllium, magnesium, aluminum, gallium, zinc, indium, tin, platinum, palladium, or iridium, more preferably beryllium, aluminum, gallium, zinc, Or iridium.

Specific examples of the metal complex include tris (8-quinolinolato) aluminum (hereinafter referred to as Alq ₃ ), tris (4-methyl-8-quinolinolato) aluminum (hereinafter referred to as Almq ₃ ), bis. (2-Methyl-8-quinolinolato)-(4-hydroxy-biphenylyl) -aluminum (hereinafter referred to as BAlq), bis (2-methyl-8-quinolinolato) -4-phenylphenolato-gallium (hereinafter referred to as BGaq) Metal complexes having a quinoline skeleton such as bis (10-hydroxybenzo [h] -quinolinato) beryllium (hereinafter referred to as BeBq ₂ ), tris (2-phenylpyridine) Iridium (hereinafter referred to as Ir (ppy) ₃ ), bis [2- (3,5-bis (trifluoromethyl) ) Phenyl) pyridinato -N, ^{C 2} '] iridium (III) picolinate _{(hereinafter,} referred to as _{Ir (CF 3 ppy) 2 (} pic)), bis [2- (4,6-difluorophenyl) pyridinato -N, C ² '] iridium (III) acetylacetonate (hereinafter referred to as FIr (acac)), bis [2- (4,6-difluorophenyl) pyridinato-N, C ² ')] iridium (III) picolinate (hereinafter referred to as “FIr (acac)”) And a metal complex having a pyridine skeleton such as FIr (pic)) and an oxazole skeleton such as bis [2- (2-hydroxyphenyl) -benzoxazolate] zinc (hereinafter referred to as Zn (BOX) ₂ ). metal complex having, bis [2- (2-hydroxyphenyl) - benzothiazolato] zinc (hereinafter, Zn _{(BTZ) 2} shows a) thiazole such as Metal complexes having a rating, or mixtures of two or more of these, and the like. In the present invention, the metal complex preferably has a quinoline skeleton or a benzoquinoline skeleton, and more preferably has a quinoline skeleton. In the present invention, it is preferable that the metal complex includes an aluminum quinolinol complex because it is excellent in solubility and handling with an oxygen atom-containing cyclic compound, more preferably includes Alq3, and most preferably Alq3. preferable. The metal complex may be a mixture of two or more kinds of metal complexes, and examples of the two or more kinds of metal complexes include the metal complexes exemplified above.

  The oxygen atom-containing cyclic compound can be used as a solvent and may have a substituent, and the heteroatom or substituent contains one or more oxygen atoms. If it is, it will not be specifically limited. Preferred examples of the oxygen atom-containing cyclic compound include cyclic esters and cyclic amides. The cyclic ester can be used as a solvent and is not particularly limited as long as it is a cyclic ester compound containing an ester functional group in the ring, but in the present invention, a light emitting layer can be formed more efficiently. The cyclic ester is preferably a lactone. Examples of the lactones include lactones such as β-lactones, γ-lactones, δ-lactones, and ε-lactones. Specific examples include γ-butyrolactone and γ-valero. Lactones, γ-caprolactone, γ-caprolactone, γ-lactones such as γ-laurolactone, δ-lactones such as δ-valerolactone, or ε-lactones such as ε-caprolactone, etc. In the present invention, the lactone is preferably a γ-lactone, more preferably γ-butyrolactone. The cyclic amide can be used as a solvent and is not particularly limited as long as it is a cyclic amide compound containing an amide group in the ring, but in the present invention, a light emitting layer can be formed more efficiently. The cyclic amide is preferably a lactam. Examples of the lactams include β-lactams, γ-lactams, δ-lactams, and more specifically, for example, γ-butyrolactam, ε-caprolactam, oxidol, itisan, glycocyanidine and the like. Is mentioned. The oxygen atom-containing cyclic compound may be a mixture of two or more oxygen atom-containing cyclic compounds, and examples of the two or more oxygen atom-containing cyclic compounds include the lactones or lactams exemplified above. And the like.

  The light emitting layer forming composition may contain a solvent other than the oxygen atom-containing cyclic compound. Such a solvent is not particularly limited as long as the object of the present invention is not impaired, and may be an organic solvent other than the oxygen atom-containing cyclic compound, or may be an inorganic solvent. A mixed solvent of an organic solvent and an inorganic solvent may be used. Examples of the organic solvent include alcohols, esters, ethers, and the like. Examples of the inorganic solvent include water, and more specifically, pure water, ultrapure water, tap water, well water, mineral spring water, mineral water, hot spring water, spring water, fresh water, seawater, and the like. In the present invention, when a solvent other than the oxygen atom-containing cyclic compound is used, the solvent is preferably an organic solvent.

  The blending ratio of the metal complex in the composition for forming a light emitting layer is not particularly limited, but is preferably 0.0001 mol% to 90 mol%, and more preferably 0.001 mol% to 50 mol%. The blending ratio of the oxygen atom-containing cyclic compound as the solvent in the composition for forming a light emitting layer is not particularly limited, but is preferably 0.01 mol% to 99 mol%, more preferably 1 mol%. -95 mol%.

    Moreover, you may mix an additive with the said composition for light emitting layer formation. The additive is not particularly limited as long as the object of the present invention is not impaired, and may be a known additive. The blending ratio of the additive in the composition for forming a light emitting layer is not particularly limited, but is preferably 0.00001 mol% to 30 mol%, and more preferably 0.0001 mol% to 10 mol%.

  The composition for forming a light emitting layer can be obtained, for example, by mixing the metal complex with the oxygen atom-containing cyclic compound. The mixing means is not particularly limited, and may be a known mixing means. More specifically, for example, it can be obtained by dissolving the metal complex in a solvent containing the oxygen atom-containing cyclic compound.

  According to the composition for forming a light emitting layer of the present invention, a light emitting layer can be produced industrially advantageously. More specifically, for example, the light emitting layer can be formed by using a known film forming means directly or via another layer from the raw material solution containing the light emitting layer forming composition. The film forming means is not particularly limited as long as it does not hinder the object of the present invention, but in the present invention, the mist CVD method is preferable, and more specifically, the raw material solution containing the composition for forming a light emitting layer is atomized. Alternatively, droplets are formed (atomization / droplet forming step), and the obtained mist or droplets are transferred onto the substrate with a carrier gas (transfer step), and the mist or droplets are reacted on the substrate, It is preferable to manufacture by laminating the light emitting layer on the substrate (film forming step). Hereinafter, such a preferable production method will be described in more detail.

(Atomization / droplet forming process)
In the atomization / droplet forming step, the raw material solution is atomized or dropletized. The atomizing means or the droplet forming means is not particularly limited as long as the raw material solution can be atomized or formed into droplets, and may be a known means, but in the present invention, the atomizing means using ultrasonic waves or A droplet forming means is preferred. Mist or droplets obtained using ultrasonic waves have a zero initial velocity and are preferable because they float in the air.For example, instead of spraying like a spray, they can be suspended in a space and transported as a gas. Since it is a possible mist, there is no damage due to collision energy, which is very suitable. The droplet size is not particularly limited and may be a droplet of several millimeters, but is preferably 50 μm or less, and more preferably 100 nm to 10 μm.

(Raw material solution)
The raw material solution contains the light emitting layer forming composition and is not particularly limited as long as it can be atomized or formed into droplets. In the present invention, the composition for forming a light emitting layer may be used as it is as a raw material solution, or a mixed solution further containing other materials may be used as a raw material solution. Examples of other materials include inorganic materials and organic materials, and the raw material solution may further contain an inorganic material or an organic material as long as the object of the present invention is not impaired. Also good. The raw material solution may further contain both inorganic and organic materials.

(Conveying process)
In the transfer step, the mist or the droplets are transferred with a carrier gas to a substrate installed in a film forming unit (for example, a film forming chamber). The carrier gas is not particularly limited as long as the object of the present invention is not impaired. For example, oxygen, ozone, an inert gas such as nitrogen or argon, or a reducing gas such as hydrogen gas or forming gas is preferable. Can be mentioned. Further, the type of carrier gas may be one, but it may be two or more, and a diluent gas with a reduced flow rate (for example, 10-fold diluted gas) is further used as the second carrier gas. Also good. Further, the supply location of the carrier gas is not limited to one location but may be two or more locations. The flow rate of the carrier gas is not particularly limited, but is preferably 0.01 to 20 L / min, and more preferably 1 to 10 L / min. In the case of a dilution gas, the flow rate of the dilution gas is preferably 0.001 to 2 L / min, and more preferably 0.1 to 1 L / min.

(Film formation process)
In the film forming step, the mist or droplet is reacted on the substrate to form a film on the substrate. The reaction may be a reaction by drying, but a thermal reaction by heat is preferable, and the thermal reaction may be any if the mist or droplet reacts with heat, and the reaction conditions also hinder the object of the present invention. Unless otherwise specified, there is no particular limitation. In this step, the thermal reaction is usually performed at 250 ° C. or lower, but in the present invention, 200 ° C. or lower is preferable, 180 ° C. or lower is more preferable, and 140 ° C. or lower is most preferable. In the present invention, since the film can be satisfactorily formed even at a low temperature, it can be applied to various kinds of substrates, and in particular, it has better adhesion without damaging the substrate, and the original properties of the film are further improved. Can demonstrate. The lower limit is not particularly limited as long as the object of the present invention is not impaired, but is preferably 80 ° C. or higher, more preferably 100 ° C. or higher, and most preferably 110 ° C. or higher. Further, the reaction may be performed under any atmosphere of vacuum, non-oxygen atmosphere, reducing gas atmosphere and oxygen atmosphere as long as the object of the present invention is not impaired. It is preferably carried out under an atmosphere. Moreover, although it may be performed under any conditions of atmospheric pressure, increased pressure, and reduced pressure, it is preferably performed under atmospheric pressure in the present invention. The film thickness can be set by adjusting the film formation time. For example, in the case of using a linear source film forming apparatus, the film thickness can be appropriately set by adjusting the number of film reciprocation scans. For example, when using a roll-to-roll film forming apparatus, the film thickness can be appropriately set by adjusting the number of nozzles and the like.

  In the present invention, the film may be formed directly on the substrate, or may be formed through another layer such as a buffer layer (buffer layer) or a stress relaxation layer. The means for forming other layers such as a buffer layer (buffer layer) and a stress relaxation layer is not particularly limited and may be a known means. In the present invention, the mist CVD method is preferable.

  The thickness of the light emitting layer is not particularly limited, but is preferably 1 nm to 100 μm, more preferably 5 nm to 50 μm, and most preferably 10 nm to 10 μm.

(Substrate)
The substrate is not particularly limited as long as it can support a film to be formed. An elastic substrate may be used. The material of the substrate is not particularly limited as long as the object of the present invention is not impaired, and may be a known substrate, an organic compound, or an inorganic compound. It may be a porous structure. The shape of the substrate may be any shape and is effective for all shapes, for example, a plate shape such as a flat plate or a disk, a fiber shape, a rod shape, a columnar shape, a prismatic shape, A cylindrical shape, a spiral shape, a spherical shape, a ring shape and the like can be mentioned. In the present invention, a substrate is preferable. Although the thickness of a board | substrate is not specifically limited in this invention, 0.5 micrometer-100 mm are preferable and 1 micrometer-10 mm are more preferable.

The substrate is not particularly limited as long as it is plate-shaped and serves as a support for a film to be formed. It may be an insulator substrate, a semiconductor substrate, a metal substrate, or a conductive substrate. A substrate in which at least one of a metal film, a semiconductor film, a conductive film, and an insulating film is formed on part or all of these surfaces can also be suitably used as the substrate. . In the present invention, the substrate is preferably a glass substrate, and more preferably a glass substrate having at least one of a metal film, a semiconductor film, a conductive film and an insulating film on the surface. . Examples of the constituent metal of the metal film include one selected from gallium, iron, indium, aluminum, vanadium, titanium, chromium, rhodium, nickel, cobalt, zinc, magnesium, calcium, silicon, yttrium, strontium, and barium. Two or more kinds of metals may be mentioned. As a constituent material of the semiconductor film, for example, an elemental element such as silicon or germanium, a compound having an element of Group 3 to Group 5 or Group 13 to Group 15 of the periodic table, metal oxide, metal sulfide , Metal selenide, or metal nitride. Examples of the constituent material of the conductive film include tin-doped indium oxide (ITO), fluorine-doped indium oxide (FTO), antimony-doped tin oxide (ATO), zinc oxide (ZnO), and aluminum-doped zinc oxide (AZO). Gallium-doped zinc oxide (GZO), tin oxide (SnO ₂ ), indium oxide (In ₂ O ₃ ), tungsten oxide (WO ₃ ), and the like. A film is preferred, a tin-doped indium oxide (ITO) film or a fluorine-doped indium oxide (FTO) film is more preferred, and a tin-doped indium oxide (ITO) film is most preferred. Examples of the constituent material of the insulating film include aluminum oxide (Al ₂ O ₃ ), titanium oxide (TiO ₂ ), silicon oxide (SiO ₂ ), silicon nitride (Si ₃ N ₄ ), and silicon oxynitride (Si _4). O ₅ N ₃ ) and the like are mentioned, but an insulating film made of an insulating oxide is preferable, and a titania film is more preferable.

  Note that the means for forming the metal film, the semiconductor film, the conductive film, and the insulating film is not particularly limited, and may be a known means. Examples of such forming means include mist CVD, sputtering, CVD (vapor deposition), SPD (spray pyrolysis deposition), vapor deposition, ALD (atomic layer deposition), and coating ( For example, dipping, dripping, doctor blade, inkjet, spin coating, brush coating, spray coating, roll coater, air knife coating, curtain coating, wire bar coating, gravure coating, inkjet coating, and the like).

  In the present invention, an anode may be formed on the substrate. The anode may be a known one, and examples of the anode include the conductive film and the metal film.

  The means for forming the anode is not particularly limited as long as the object of the present invention is not impaired. In the present invention, a known means can be used as the means for forming the anode. Examples of the anode forming means include mist CVD, sputtering, CVD (vapor phase growth), SPD (spray pyrolysis deposition), and vapor deposition.

  The thickness of the anode is not particularly limited and can be appropriately selected depending on the material constituting the anode, but is usually 10 nm to 500 μm, and preferably 50 nm to 200 μm.

  In the present invention, it is preferable to form another layer on the substrate on which the anode is formed, and a hole transport layer is further formed on the substrate on which the anode is formed. Is more preferable. The constituent material of the hole transport layer is not particularly limited, and may be a known material. In the present invention, the constituent material of the hole transport layer is preferably an amine derivative, more preferably an arylamine derivative, and most preferably a tertiary arylamine derivative or a benzidine-based amine derivative. . Examples of the tertiary arylamine derivative include 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (abbreviation: α-NPD) and N, N′-bis (3- Methylphenyl) -N, N′-diphenyl- [1,1′-biphenyl] -4,4′-diamine (abbreviation: TPD), 4,4 ′, 4 ″ -tris (N, N-diphenylamino) Triphenylamine (abbreviation: TDATA), 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (abbreviation: MTDATA), N, N′-bis ( Spiro-9,9′-bifluoren-2-yl) -N, N′-diphenylbenzidine (abbreviation: BSPB), N, N′-bis (4-methylphenyl) (p-tolyl) -N, N′- Diphenyl-p-phenylene Amine (abbreviation: DTDPPA), 4,4′-bis [N- (4-diphenylaminophenyl) -N-phenylamino] biphenyl (abbreviation: DPAB), 4,4′-bis (N- {4- [N '-(3-methylphenyl) -N'-phenylamino] phenyl} -N-phenylamino) biphenyl (abbreviation: DNTPD), 1,3,5-tris [N- (4-diphenylaminophenyl) -N- Phenylamino] benzene (abbreviation: DPA3B) or a mixture of two or more thereof. Examples of the benzidine-based amine derivative include 4,4′-bis [N- (1-naphthyl) -N-phenylamino. ] Biphenyl (abbreviation: α-NPD) and N, N′-bis (3-methylphenyl) -N, N′-diphenyl- [1,1′-biphenyl] -4,4′-diamine Abbreviation: TPD), N, N′-bis (spiro-9,9′-bifluoren-2-yl) -N, N′-diphenylbenzidine (abbreviation: BSPB), N, N, N ′, N′-tetra And naphthyl-benzidine (abbreviation: TNB) or a mixture of two or more thereof.

  The means for forming the hole transport layer is not particularly limited as long as the object of the present invention is not impaired, and may be a known means. Examples of the hole transport layer forming means include mist CVD, sputtering, CVD (vapor deposition), SPD (spray pyrolysis deposition), vapor deposition, ALD (atomic layer deposition), Application methods (for example, dipping, dripping, doctor blade, inkjet, spin coating, brush coating, spray coating, roll coater, air knife coating, curtain coating, wire bar coating, gravure coating, inkjet coating, etc.) can be mentioned.

  The thickness of the hole transport layer is not particularly limited, but it is preferably 1 nm to 5 μm, and preferably 5 nm to 1 μm, from the viewpoints of lowering driving voltage, improving external quantum efficiency, and improving durability. More preferably, it is 10 nm to 500 nm.

  In the present invention, it is preferable to form the light emitting layer on a substrate on which the anode and the hole transport layer are formed in this order, and by forming the light emitting layer in this manner, An organic light emitting device can be obtained efficiently.

  By producing as described above, a light-emitting layer can be obtained simply and easily, efficiently and industrially advantageously. Moreover, the film thickness of the light emitting layer obtained can also be easily adjusted by adjusting the film-forming time.

  The light emitting layer is useful for organic light emitting devices and the like. In the present invention, when the light emitting layer is used in an organic light emitting device, for example, it is suitably used as a light emitting layer of an organic light emitting device having at least an anode, a hole transport layer, a light emitting layer, and optionally an electron transport layer and a cathode. be able to. In this case, for example, an organic light emitting device in which an anode, a hole transport layer, a light emitting layer, an electron transport layer, and a cathode as desired are formed in this order on the substrate can be cited as a suitable example, but the present invention is not limited thereto. .

  Hereinafter, a suitable example when the light emitting layer is used in an organic light emitting device will be described. On the substrate, the anode, the hole transport layer, the light emitting layer, and optionally an electron transport layer and a cathode are formed in this order.

(Electron transport layer)
The electron transport layer usually has one of a function of injecting electrons from the cathode, a function of transporting electrons, and a function of blocking holes that can be injected from the anode. The constituent material of the electron transport layer is not particularly limited, and may be a known material. Examples of the constituent material of the electron transport layer include pyridine, pyrimidine, triazine, imidazole, triazole, oxazole, oxadiazol, fluorenone, anthraquinodimethane, anthrone, diphenylquinone, thiopyran dioxide, and carbodiimide. , Fluorenylidenemethane, distyrylpyrazine, fluorine-substituted aromatic compounds, heterocyclic tetracarboxylic anhydrides such as naphthaleneperylene, phthalocyanines, and derivatives thereof (may form condensed rings with other rings), 8 -Metal complexes of quinolinol derivatives and various metal complexes represented by metal complexes having metal phthalocyanine, benzoxazole or benzothiazol as a ligand.

  The thickness of the electron transport layer is not particularly limited, but the thickness is preferably 1 nm to 5 μm, more preferably 5 nm to 1 μm, from the viewpoint of driving voltage reduction, external quantum efficiency improvement, and durability improvement. Preferably, it is 10 nm to 500 nm.

  The means for forming the electron transport layer is not particularly limited as long as the object of the present invention is not impaired, and may be a known means. As the means for forming the electron transport layer, for example, a mist CVD method, a sputtering method, a CVD method (vapor deposition method), an SPD method (spray pyrolysis deposition method), a vapor deposition method, an ALD (atomic layer deposition) method, a coating method, etc. (For example, dipping, dripping, doctor blade, inkjet, spin coating, brush coating, spray coating, roll coater, air knife coating, curtain coating, wire bar coating, gravure coating, inkjet coating, etc.). In the present invention, the electron transport layer forming means is preferably a mist CVD method.

(cathode)
The cathode is not particularly limited as long as it has conductivity and functions as an electrode, and may be a known cathode. For example, even if it is an insulating material, if a conductive substance layer is provided on the side facing the electron transport layer and can be used as an electrode, it can be used as a cathode. In the present invention, the cathode preferably has good contact with the electron transport layer. The cathode preferably has a small work function difference from the electron transport layer and is chemically stable. Such a material is not particularly limited, but is a metal thin film such as gold, silver, copper, aluminum, platinum, rhodium, magnesium, indium, carbon, carbon black, a conductive polymer, a conductive metal oxide (indium -Organic conductors such as tin composite oxide, tin oxide doped with fluorine, and the like. Also, the average thickness of the cathode is not particularly limited, but is preferably about 10 to 1000 nm. The surface resistance of the cathode is not particularly limited but is preferably low. Specifically, the surface resistance range of the cathode is preferably 80Ω / □ or less, more preferably 20Ω / □ or less. The lower limit of the surface resistance of the cathode is preferably as low as possible and is not particularly limited, but may be 0.1Ω / □ or more.

  The method for forming the cathode is not particularly limited as long as the object of the present invention is not impaired, and known means can be used. Examples of the cathode forming means include mist CVD, sputtering, CVD (vapor deposition), SPD (spray pyrolysis deposition), and vapor deposition.

  The organic light-emitting element is useful as a light-emitting element used for a display device, a lighting device, or the like, and is suitably used for an electronic device or a component thereof including the display device, the lighting device, or the like. The said electronic device or its components can be produced using a known means.

  Hereinafter, the suitable aspect at the time of using the organic light emitting element of this invention for an electronic device or its components is shown. In the module shown in FIG. 2, a region 121 exposed from the sealing substrate is provided on one side of the driving substrate 105, and the wirings of the signal line driver circuit 112 and the scanning line driver circuit 113 are extended to the region 121. A connection terminal (not shown) is formed. The external connection terminal is provided with a flexible printed wiring board 122 for signal input / output.

  On the driving substrate 105 shown in FIG. 3, for example, a display region 111 and a signal line driving circuit 112 and a scanning line driving circuit 113 which are drivers for video display are formed. A pixel drive circuit 114 is formed in the display area 111. In the display region 111, the organic light emitting elements 101R, 101G, and 101B are arranged in a matrix as a whole. The organic light emitting elements 101R, 101G, and 101B are formed in a strip-like planar shape, and one pixel is formed by a combination of the organic light emitting elements 101R, 101G, and 101B.

  The pixel driving circuit 114 is an active driving circuit that is formed under the electrode and includes a driving transistor and a writing transistor, a capacitor (holding capacitor) Cs, and an organic light emitting element. In the pixel driving circuit 114, a plurality of signal lines 112A are arranged in the column direction, and a plurality of scanning lines 113A are arranged in the row direction. An intersection of each signal line 112A and each scanning line 113A corresponds to one of the organic light emitting elements 101R, 101G, and 101B (sub pixel). Each signal line 112A is connected to a signal line driving circuit 112, and an image signal is supplied from the signal line driving circuit 112 to the source electrode of the writing transistor via the signal line 112A. Each scanning line 113A is connected to a scanning line driving circuit 113, and a scanning signal is sequentially supplied from the scanning line driving circuit 113 to the gate electrode of the writing transistor via the scanning line 113A.

  The module is incorporated in various electronic devices or parts thereof and used as, for example, a display device. The electronic device is not particularly limited as long as it is an electronic device in which the organic light emitting element is used. Examples thereof include a television, a camera, a personal computer, a mobile phone, a smartphone, and a display. Further, the means for incorporating the module into the electronic device or its components is not particularly limited, and may be a known means.

  Further, the organic light emitting device of the present invention is not particularly limited to the example of the module and can take any form, and a system using the module or the electronic device is also included in the present invention. . The system is not particularly limited as long as it is a system in which the organic light emitting element is used, and examples thereof include an illumination system and a communication system.

  Examples of the present invention will be described below, but the present invention is not limited thereto.

Example 1
1. Film Forming Apparatus A mist CVD apparatus 1 used in this example will be described with reference to FIG. The mist CVD apparatus 1 includes a carrier gas source 2 for supplying a carrier gas, a flow rate adjusting valve 3 for adjusting the flow rate of the carrier gas sent out from the carrier gas source 2, and a mist generation source 4 in which a raw material solution 4a is accommodated. A container 5 for containing water 5a, an ultrasonic transducer 6 attached to the bottom surface of the container 5, a hot plate 8, a substrate 10 placed on the hot plate 8, and a substrate from the mist generating source 4. And a supply pipe 9 for connecting up to 10 vicinity.

2. Preparation of raw material solution α-NPD was mixed with γ-butyrolactone to obtain a raw material solution. The concentration of α-NPD in the solution was 0.0020 mol / L.

3. Preparation of film formation The raw material solution 4a obtained in the above was accommodated in the mist generating source 4. Next, a 15 mm square glass / ITO substrate was placed on the hot plate 8 as the substrate 10, and the hot plate 8 was operated to raise the temperature of the substrate 10 to 180 ° C. Next, the flow rate adjusting valve 3 was opened, and the flow rate of the carrier gas supplied from the carrier gas supply means 2 as the carrier gas source was adjusted to 4 L / min. Nitrogen was used as the carrier gas.

4). Formation of hole transport layer Next, the ultrasonic vibrator 6 is vibrated at 2.4 MHz, and the vibration is propagated to the raw material solution 4a through the water 5a, whereby the raw material solution 4a is atomized to generate the mist 4b. I let you. The mist 4b is transported to the substrate 10 by the carrier gas through the supply pipe 9, and the mist reacts thermally near the substrate 10 at 180 ° C. under atmospheric pressure. A transport layer was formed. In addition, the film thickness of the obtained positive hole transport layer was about 50 nm, and the film-forming time was 10 minutes. Further, the fluorescence spectrum of the obtained laminate was measured at an excitation wavelength of 300 nm. FIG. 4 shows the result. As can be seen from FIG. 4, the obtained laminate had an emission peak at a wavelength of 430 to 450 nm.

5). Formation of Light-Emitting Layer Using Alq3 instead of α-NPD, a mixed solution was prepared by setting the concentration of Alq3 in the solution to 0.0025 mol / L, and this was used as a raw material solution. The same as in the formation of the hole transport layer, except that the laminate obtained in (4) was used. A light emitting layer was formed on the hole transport layer formed in (1). Moreover, the film thickness of the obtained light emitting layer was about 50 nm, and the film-forming time was 10 minutes. Further, the fluorescence spectrum of the obtained laminate was measured at an excitation wavelength of 300 nm. FIG. 5 shows the result. As can be seen from FIG. 5, the obtained laminate had an emission peak at a wavelength of 500 to 520 nm.

6). Formation of cathode 5. On the light emitting layer formed in (1), aluminum was formed as a cathode using a vacuum vapor deposition method, and an organic light emitting device was fabricated.

(Example 2)
An organic light emitting device was produced in the same manner as in Example 1 except that the film forming temperature at the time of forming the hole transport layer and the light emitting layer was 140 ° C. Moreover, the fluorescence spectrum was measured about each laminated body obtained by the positive hole transport layer formation process (corresponding to 4. of Example 1) and the light emitting layer formation process (corresponding to 5. of Example 1). The results are shown in FIG. 4 and FIG. As can be seen from FIG. 4 and FIG. And 5. It was the same as each of the laminates obtained in. The emission intensity is the same as that in Example 1. And 5. It was higher than each of the laminates obtained in 1 and had better light emission characteristics.

  When the composition for forming a light emitting layer of the present invention is used, the light emitting layer can be produced simply and easily, efficiently and industrially advantageously, and thus can be used in various industries. In particular, the present invention can be used in industrial fields such as electronic devices equipped with display devices, lighting devices, and the like.

DESCRIPTION OF SYMBOLS 1 Mist CVD apparatus 2 Carrier gas source 3 Flow control valve 4 Mist generation source 4a Raw material solution 4b Mist 5 Container 5a Water 6 Ultrasonic vibrator 8 Hot plate 9 Supply pipe 10 Substrate 101R Organic light emitting element 101G Organic light emitting element 101B Organic light emitting element 105 driving substrate 111 display area 112 signal line driving circuit 112A signal line 113 scanning line driving circuit 113A scanning line 114 pixel driving circuit 121 area 122 flexible printed wiring board

Claims (12)

  A composition for forming a light emitting layer, which is used for forming a light emitting layer, comprising a metal complex and an oxygen atom-containing cyclic compound as a solvent.   The composition for forming a light emitting layer according to claim 1, wherein the metal complex has a quinoline skeleton or a benzoquinoline skeleton.   The composition for forming a light emitting layer according to claim 1, wherein the metal complex is an aluminum quinolinol complex.   The composition for light emitting layer formation in any one of Claims 1-3 whose said metal complex is Alq3.   The composition for forming a light emitting layer according to any one of claims 1 to 4, wherein the oxygen atom-containing cyclic compound is a lactone or a lactam.   The composition for forming a light emitting layer according to any one of claims 1 to 5, wherein the oxygen atom-containing cyclic compound is γ-butyrolactone.   It is a manufacturing method of the light emitting layer which forms a light emitting layer from a raw material solution directly on a base | substrate through another layer, Comprising: The said raw material solution is a composition for light emitting layer formation in any one of Claims 1-6. A manufacturing method of a light emitting layer characterized by including.   The formation of the light emitting layer is performed by atomizing or dropletizing the raw material solution, transporting the obtained mist or droplets onto the substrate with a carrier gas, reacting the mist or droplets on the substrate, The manufacturing method according to claim 7, which is performed by laminating a light emitting layer on the substrate.   The light emitting layer manufactured by the manufacturing method of Claim 7 or 8.   An organic light emitting device having at least an electrode, a hole transport layer, and a light emitting layer, wherein the light emitting layer is the light emitting layer according to claim 9.   The electronic device containing the organic light emitting element of Claim 10, or its component. The system provided with the electronic device of Claim 11, or its components.