JP2011218282A - Method for producing thin film, and production apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing thin film having higher film density using the spray film-forming method.SOLUTION: The method for producing thin film includes the sequential steps: forming liquid drops by spraying stock solution in which a solute is dissolved or dispersed in a solvent; volatilizing and concentrating the solvent in the liquid drops; and depositing the concentrated liquid drops on a substrate or thin film provided on the substrate. In the method, liquid drops with mutually different drop sizes are simultaneously deposited.

Description

  The present invention relates to various devices such as organic electroluminescent elements and solar cells, and a thin film manufacturing method and thin film manufacturing apparatus that can be used for various optical members such as a reflector and a polarizing plate.

With the expansion of networks and diversification of lifestyles in recent years, added value that is difficult to realize with conventional Si semiconductors such as flexibility and large area is required for electronic devices, and organic electronics that can be deposited on films is attracting attention Has been.
In various organic devices such as organic electroluminescent elements and solar cells, it is important to form organic thin films having different functions in order to improve performance. As a method for producing a thin film, a dry process such as a vacuum deposition method and a wet process such as a spin coating method are generally known.
The dry process can be formed by laminating a uniform organic thin film with a constant thickness, but it cannot be applied to a thermally unstable organic material because high energy is applied to the material to be formed. Since the material is also limited to a heat-resistant material such as glass, the material and the substrate are limited. In addition, there is a problem that productivity is poor because there are many vacuum processes.

  On the other hand, since the wet process can be easily formed on a flexible substrate such as a film, it is much superior to the dry process in terms of productivity and area increase. For example, an extrusion coating method described in Non-Patent Document 1 and the like is known as a film forming method using a coating solution prepared using an organic solvent. According to this method, simultaneous application of a laminated film is also possible. However, the coating method requires a certain degree of viscosity in the coating solution. Many materials of the organic light emitting layer are difficult to dissolve in a solvent, and it is difficult to prepare a highly concentrated coating solution having a high viscosity. Moreover, since adding a binder, a thickener, etc. in each layer of an organic electronic device may lead to a performance fall, addition of the additive with a thickening effect is also unsuitable. Therefore, in many cases, only a dilute solution having a very low solid content concentration can be prepared for the material of the organic light emitting layer. In order to form an organic thin film having desired characteristics using such a very low concentration solution, it is necessary to apply the solution thickly, but it is difficult to apply a low viscosity solution thickly. As a result, a uniform coating film cannot be obtained. Moreover, even if it was possible to produce a single layer thin film by the above coating method, when trying to produce a laminated film by the same method, the lower layer was dissolved by a large amount of solvent in the upper layer coating, The production of the laminated film is further difficult. Although it is conceivable to use a solvent that does not dissolve the lower layer when forming the upper layer, the type of solvent is limited, so that only materials that can be dissolved in the solvent can be laminated. There is a problem that the material is limited.

In addition, a method for manufacturing an organic electroluminescent element using a spray method (for example, Patent Document 1) has also been proposed. However, even when the spray method is used, it is difficult to avoid the problem that the upper layer solvent dissolves the lower layer when producing a laminated film.
In addition, a method of forming an organic thin film by aerosolizing a raw material liquid and depositing it on a substrate has been proposed (for example, Patent Document 2). According to this method, it is possible to form a laminated film without dissolving the lower layer with the upper layer solvent in spite of the wet process. Therefore, there is a possibility that the problems of the dry process and the wet process can be solved. From the viewpoint of avoiding dissolution of the lower layer by the upper layer solvent, the smaller the amount of the solvent remaining in the droplet when it reaches the substrate, the better. However, when the amount of the solvent is reduced, the viscosity of the droplet becomes very high and is deposited on the substrate while maintaining the particle shape. In addition, the distribution of the droplet size sprayed from a single spray nozzle is almost the same as the droplet size, although there is some spread, and voids are generated in the film deposited on the substrate. In the case of an organic electroluminescent element or the like, if the void is included in the film, the element performance such as luminance unevenness is deteriorated. In terms of film strength and adhesion, internal stress tends to concentrate in the voids of the film, or the contact area with the substrate is reduced, resulting in decreased film strength and adhesion, and subsequent electrode connection. This causes the film to be destroyed during the process of device formation such as sealing.

JP 2008-243421 A JP 2004-160388 A

Stephen F. Kistler, Petert M. Schwaizer, “LIQUID FILM COATING” (CHAPMAN & HALL 1997), pages 401-426

This invention makes it a subject to solve the problem that the space | gap by a residual solvent generate | occur | produces in the thin film formed by the spray film forming method.
More specifically, an object of the present invention is to provide a method capable of producing a uniform thin film without voids by a wet process.
Another object of the present invention is to improve the density of a thin film produced by a wet process.
It is another object of the present invention to provide a method capable of producing a thin film and a laminated thin film with improved film density and adhesion with a lower layer, and a thin film production apparatus used in the method.

  As a result of intensive studies by the inventor in order to solve the above-mentioned problems, it is possible to simultaneously spray raw material liquids having different solid content concentrations, or simultaneously spray droplet sizes of different sizes, so that small liquids can be interposed between large liquid droplets. It was found that when the droplets enter, the voids are reduced and the film density is improved. Further studies based on this finding led to the completion of the present invention.

Means for solving the above problems are as follows.
[1] Spraying a raw material solution obtained by dissolving and / or dispersing a solute in a solvent to form droplets;
Volatilizing and concentrating the solvent in the droplets;
Depositing concentrated droplets on a substrate or on a thin film provided on the substrate;
A method for producing a thin film sequentially comprising:
A method for producing a thin film, wherein droplets having different droplet diameters are simultaneously deposited on a substrate.
[2] The method according to [1], wherein the raw material liquids having the same solid content composition but different solid content concentrations are sprayed simultaneously from each of the two or more nozzles.
[3] The method according to [2], wherein raw material liquids having the same solid content composition but different solid content concentrations are sprayed as droplets having the same diameter.
[4] The method according to [1], wherein the same raw material liquid is sprayed simultaneously as droplets having different droplet diameters from each of the two or more nozzles.
[5] The method according to [4], wherein the droplets to be sprayed exhibit a droplet size distribution having two or more peaks.
[6] The method according to any one of [1] to [5], wherein droplets containing at least one kind of solvent that dissolves the material of the substrate or the material of the thin film provided on the substrate are deposited.

[7] Any one of [1] to [6], wherein the raw material liquid contains at least one selected from an organic semiconductor, an organic light emitting material, an organic electron transport material, and an organic hole transport material. the method of.
[8] A method for producing any one of an organic semiconductor layer, a light emitting layer, an electron transport layer, an electron injection layer, a hole transport layer, and a hole injection layer [1] to [7 ] One of the methods.
[9] Producing a single-layer thin film of the lower layer having the same solid content composition by any one of the methods [1] to [8]
On the lower single-layer thin film, an upper single-layer thin film having a part or all of the solid content composition different from that of the lower single-layer thin film is produced by any one of the methods [1] to [8].
A method for producing a laminated thin film containing at least
[10] An apparatus for producing an organic thin film used in any one of the methods [1] to [9],
Droplet forming means having two or more nozzles for forming droplets of a raw material liquid obtained by dissolving and / or dispersing a solute in a solvent;
Raw material liquid supply means for supplying the raw material liquid to the droplet forming means;
Gas supply means for supplying gas to the droplet forming means;
An apparatus for producing a thin film, comprising: a droplet heating unit for heating a droplet provided in connection with the droplet forming unit; and a substrate holder for fixing the substrate.
[11] The apparatus according to [10], further comprising substrate heating means for heating the substrate provided by connecting the substrate to the holder.

ADVANTAGE OF THE INVENTION According to this invention, the problem that the space | gap by a residual solvent generate | occur | produces in the thin film formed by the spray film forming method can be solved.
More specifically, according to the present invention, it is possible to provide a method capable of producing a uniform thin film without voids by a wet process while avoiding dissolution of the lower layer.
It is another object of the present invention to provide a method capable of producing a thin film and a laminated thin film with improved film density and adhesion with a lower layer, and a thin film production apparatus used in the method.

It is a schematic diagram of an example of the manufacturing apparatus of the thin film of this invention. It is an example of the droplet distribution of the droplet deposited on the substrate in the method of the present invention.

Hereinafter, the present invention will be described in detail.
The present invention
Spraying a raw material solution obtained by dissolving and / or dispersing a solute in a solvent to form droplets;
Volatilizing and concentrating the solvent in the droplets;
Depositing concentrated droplets on a substrate or on a thin film provided on the substrate;
A method for producing a thin film sequentially comprising:
The present invention relates to a method for manufacturing a thin film, in which droplets having different droplet diameters are simultaneously deposited on a substrate.
One of the characteristics of the thin film manufacturing method of the present invention is to give a width to the droplet diameter distribution when reaching the substrate. Thereby, small droplets can enter between large droplets, voids are reduced, and film density is improved. As a result, for example, in an embodiment in which an organic thin film constituting an organic electric field element such as a light emitting element is manufactured, unevenness in luminance is reduced by improving the film density, and element performance such as light emission performance is improved. In addition, physical properties of the film such as film strength and adhesion can be improved.

  In general, in the spray film forming method, the droplet diameters of the deposited droplets are not completely uniform and have a certain distribution. In the present invention, it is preferable that the deposited droplet diameter not only has a distribution but also the deposited droplet exhibits a droplet size distribution having a plurality of peaks. An example is the droplet size distribution shown in FIG.

Hereinafter, each process of the manufacturing method of this invention is demonstrated in detail.
(1) Droplet formation step First, a raw material liquid obtained by dissolving and / or dispersing an organic material in a solvent is sprayed to form droplets. There are no particular restrictions on the materials and solvents used in the preparation of the raw material liquid. In order to form an organic thin film having desired physical properties, various materials are selected. In the method of the present invention, since the material is not exposed to excessively high temperature, there is no limitation on heat resistance and the like. It may be a high molecular material or a low molecular material. Moreover, a metal complex etc. may be sufficient. Therefore, what is suitable from the viewpoint of affinity with the material can be selected from the solvent. Of course, water may be used as a solvent, or a mixed solvent of water and an organic solvent may be used. Examples of solvents suitable for spraying include tetrahydrofuran, methyl ethyl ketone, toluene, methanol, ethanol, hexane, benzene, acetone, diethyl ether, cyclohexanone, chlorobenzene, chloroform and the like.

  In addition, as the solvent used for preparing the raw material liquid, at least one solvent that dissolves the material of the substrate on which the droplets are deposited or the material of the thin film provided on the substrate can be used. This is because the solid content concentration of the droplets reaching the substrate and the lower layer thin film is higher in the concentration step, that is, the amount of solvent in the droplets when reaching the substrate is small, so the substrate etc. is the solvent in the droplets. This is because it dissolves only slightly. In addition, the dissolution of the substrate or the like with this small amount of solvent is preferable because it promotes the bonding between the film to be formed and the substrate or thin film underneath, thereby improving the adhesion. Performance is improved by mitigating the influence of the interface that acts as a barrier to electron and hole movement.

In the droplet forming step, the raw material liquid is sprayed to form droplets. There is no restriction | limiting in particular about the method of making it into droplets, A various method can be utilized. For example, by mixing the raw material liquid with a carrier gas having a predetermined gas pressure and flow rate, the raw material liquid can be made into droplets suspended in the carrier gas. There is no restriction | limiting in particular as carrier gas. Air may be used. In order not to change the raw material, an inert gas is preferable, and nitrogen, argon, helium, or the like is preferably used. The gas pressure and flow rate of the carrier gas can be controlled using a regulator. The droplet formation can also be performed using ultrasonic vibration or the like.
There is no particular limitation on the method of supplying the raw material liquid to the droplet forming means, and various methods can be used. For example, it is possible to use a syringe pump or a tactile pump capable of precise liquid feeding with little pulsation.
Although there is no restriction | limiting in particular about the particle size of a droplet, Generally, it is preferable that it is about 0.1-100 micrometers, and it is more preferable that it is about 1-10 micrometers.

  Regarding the density | concentration of the raw material liquid to spray, 0.00001 mass%-1 mass% are desirable, and 0.0001 mass%-0.01 mass% are more preferable.

In the present invention, it is preferable to use two or more nozzles in the droplet formation step in order to deposit droplets having different droplet diameters on the substrate at the same time in the deposition step described later. By using two or more nozzles, droplets of raw material liquids with different concentrations or by spraying the same raw material liquid with different droplet diameters, droplets with different droplet diameters are simultaneously deposited on the substrate. Can do.
In one embodiment of the present invention, raw material liquids having the same solid content composition but different solid content concentrations are sprayed simultaneously from each of the two or more nozzles. In this embodiment, for example, when the raw material liquids having different concentrations are sprayed from the respective nozzles as droplets of the same diameter, the liquid droplets of the raw material liquid having a high solid content concentration are the same diameter of the raw material liquid having a low solid content concentration It contains a smaller amount of solvent compared to the other droplets. In the concentration step described later, the solvent is removed from the droplets, but the amount of the solvent removed from the droplets of the raw material liquid having a high solid content concentration is compared with the droplets of the same diameter of the raw material liquid having a low solid content concentration. Thus, it can be said that the change in the droplet diameter is smaller, that is, smaller before and after the concentration step. As a result, when the substrate arrives, that is, at the time of deposition, the droplet diameter of the raw material liquid droplet with a high solid content concentration becomes larger than the droplet diameter of the raw material liquid droplet with a low solid content concentration. Droplets having different droplet diameters can be simultaneously deposited on the substrate.

  In the said embodiment, when the solid content concentration ratio of the raw material liquid sprayed from each nozzle is 1.5: 1 to 100: 1 (more preferably, 2: 1 to 20: 1), two peaks are obtained. Droplets exhibiting a droplet size distribution can be deposited on the substrate. Two or more raw material liquids satisfying the above-described concentration ratio relationship are prepared and sprayed as droplets having the same droplet diameter from each nozzle, whereby droplets having a droplet diameter distribution having two or more peaks are formed on the substrate. Can be deposited.

  In another embodiment of the present invention, the same raw material liquid is sprayed simultaneously as droplets having different droplet diameters from each of two or more nozzles. In this embodiment, since the same raw material liquid is sprayed with different droplet diameters, the solid content concentration of each droplet is the same, and even when the solvent is removed through the concentration step described later, While maintaining the difference in diameter between the droplets, the droplets reach the substrate and deposit on the substrate. As a result, droplets having different droplet diameters can be simultaneously deposited on the substrate.

In the said embodiment, when the ratio of the droplet diameter of the droplet sprayed from each nozzle is 1.1: 1 to 500: 1 (preferably 1.2: 1 to 50: 1), it is 2 Droplets showing a droplet size distribution with two peaks can be deposited on the substrate. By spraying the same raw material liquid from each nozzle under the condition satisfying the relationship of the droplet diameter ratio, droplets having a droplet diameter distribution having two or more peaks can be deposited on the substrate.
Further, if the droplets to be sprayed exhibit a droplet size distribution having two or more peaks, the droplets are deposited on the substrate while maintaining the droplet size distribution unless the droplets are heated excessively in the concentration step. Therefore, droplets having a droplet size distribution having two or more peaks can be deposited on the substrate.

  Moreover, you may spray the raw material liquid from which solid content concentration differs with time. For example, the raw material liquid having a predetermined concentration may be sprayed from two or more nozzles with different droplet diameters, and then the raw material liquid having a different concentration may be sprayed from two or more nozzles with different droplet diameters. In that case, it is preferable to spray at the density | concentration of 0.0001-1 mass% at the initial stage of spraying, and to spray at the density | concentration of 0.00001-0.1 mass% after that.

  In the present specification, “the same solid content composition” means that the material constituting the thin film is the same, and when there are a plurality of materials, the composition ratio is also the same. “The same raw material liquid” refers to the same raw material liquid for both “solid component composition” and “solid content concentration”.

  The material used as the solute of the raw material liquid to be sprayed can be selected from, for example, organic materials used for the production of each organic thin film layer of an organic electronic device such as an organic EL. An example is an organic material for a light emitting layer of an organic EL, and an organic compound for a light emitting material and a host material. Details of various compounds that are materials for each organic thin film of the organic EL element and that can be used as the solute of the raw material liquid in the production method of the present invention will be described later.

(2) Concentration step Next, the droplets formed in the droplet formation step are concentrated. It is preferably generated in a partitioned space such as a chamber and ejected from a chamber opening of a predetermined shape toward the substrate. It is preferable to heat the droplet before ejecting the droplet from the chamber opening toward the substrate. By heating, the solvent in the droplets is removed, resulting in a mist having a small particle size and a high solid content concentration. The heating temperature is preferably set to a temperature not higher than the boiling point of the solvent used for preparing the raw material liquid.

(3) Deposition step Next, droplets are deposited on the substrate to form a thin film. In the present invention, in the deposition step, droplets having different droplet diameters are simultaneously deposited. This allows small droplets to enter between large droplets, reducing voids and improving film density. As a result, for example, in an embodiment in which an organic thin film constituting an organic electric field element such as a light emitting element is manufactured, unevenness in luminance is reduced by improving the film density, and element performance such as light emission performance is improved. In addition, physical properties of the film such as film strength and adhesion can be improved.

In the deposition step, the droplets having different droplet diameters may be deposited at the same time only within a predetermined time. That is, only for a predetermined time until the thin film is produced, droplets having different droplet sizes are deposited simultaneously in the deposition step, and droplets having a uniform droplet size are deposited at other times. Also good. In order to improve the adhesion with a lower layer such as a substrate, it is preferable to simultaneously deposit droplets having different droplet diameters at the beginning of deposition.
In order to obtain the effect of improving the film density, which is the effect of the present invention, it is preferable to deposit at least about 1 to 50 nm of droplets having different droplet diameters at the same time. Even if droplets having a uniform droplet diameter are deposited before and after that, an effect of improving the film density will be obtained.

(4) Lamination process Moreover, this invention is useful also for the preparation methods of laminated film. By repeating the steps (1) to (3) n (n is an integer of 2 or more) times, an n-layer laminated thin film can be produced. Specifically, after the steps (1) to (3) are used to form a single layer thin film (lower layer thin film) having the same solid composition with high surface smoothness and having a high film density, solids are formed on the lower layer thin film. By repeating the steps (1) to (3) using raw material liquids having different composition, an upper thin film can be formed and a laminated film can be produced. Since the upper thin film is also produced by the above steps (1) to (3), dissolution of the lower layer by the solvent in the upper liquid droplet can be avoided, and a laminated thin film having a high film density can be produced. it can. The raw material liquid used for forming the upper layer is different from the raw material liquid used for forming the lower layer in at least a part of the solid content composition. For example, one or more materials may be different and / or the proportion of materials may be different.

  The thickness of the thin film formed by the method of the present invention is not particularly limited, but the method of the present invention is particularly advantageous for forming a thin film, particularly suitable for forming a thin film of about 0.001 to 10 μm, and more Preferably, it is 0.01-1 micrometer, More preferably, it is 0.01-0.1 micrometer.

  In the present invention, the gas may flow in the same direction as the mist generation direction, that is, in the substrate direction. An inert gas is preferable as the gas, and nitrogen, argon, helium, or the like is preferably used. By flowing the gas, the film forming rate can be improved.

In the present invention, a potential may be applied to the substrate partially or entirely. By applying a potential to the substrate to create a potential difference with the droplets, the suction force on the droplets of the substrate is increased, so that the droplets can be prevented from adhering to other portions, and the film formation rate can be improved. Further, the organic thin film density can be adjusted by applying a potential to the substrate. In a mode in which the droplet is charged, it is preferable to give the substrate a potential opposite to that of the droplet. Specifically, in order to generate a potential difference, specifically, a potential opposite to the charge that the droplet is potentialated. Is preferred.
As described above, a desired pattern / image-shaped organic thin film can be formed by partially applying a potential to the substrate.

  The droplets are deposited on the substrate surface and become an organic thin film. If necessary, it may be further dried. Drying can be carried out by supplying heat to the substrate from a member or the like that supports the substrate, and preheating the substrate surface to a high temperature. Moreover, you may dry by supplying warm air. The drying is preferable because the solvent remaining in the formed film is removed.

FIG. 1 shows a schematic diagram of an example of a film forming apparatus capable of performing the thin film manufacturing method of the present invention.
The film forming apparatus of FIG. 1 includes two two-fluid nozzles 12a and 12b, and the raw material liquid supplied from the syringe pumps 14a and 14b is supplied from the gas cylinders 18a and 18b with the flow rate controlled by the regulators 16a and 16b. Gas (for example, N ₂ gas) is mixed inside the two-fluid nozzles 12a and 12b, and sprayed as droplets inside the chamber 20, respectively. The inside of the chamber 20 is configured to be able to control the temperature, for example, by passing hot water and hot air through a heater provided around the outside and a flow path around the outside. The droplets sprayed from the nozzle are concentrated inside the chamber 20, and the concentrated droplets are deposited on the surface of the substrate 22 supported by the substrate holder 24 to form a film.

In one embodiment of the present invention, raw material liquids having different solid content concentrations are sprayed as droplets having the same droplet diameter from each of the two-fluid nozzles 12a and 12b.
In another embodiment, the same raw material liquid is sprayed as droplets having different droplet diameters from each of the two-fluid nozzles 12a and 12b. In this embodiment, in order to obtain a desired droplet diameter, the liquid feed amount of the pumps 14a and 14b that supplies the raw material liquid to each nozzle and / or the pressurization amount of the regulators 16a and 16b that supply the gas to each nozzle To control.

  Furthermore, it is preferable to provide means for heating the substrate 22 because the residual solvent is further removed and the density of the formed thin film is further improved. For example, the heat treatment can be performed by supplying heat to the substrate from the substrate holder 24 that supports the substrate, and previously setting the substrate surface to a high temperature. Moreover, you may dry by supplying warm air.

  However, the film forming apparatus shown in FIG. 1 is an example, and is not limited to the configuration shown in FIG. For example, the number of nozzles is not limited to two, and may be three or more. Further, the film forming apparatus shown in FIG. 1 has a voltage applying means for applying a potential to the substrate, a blowing means for blowing an inert gas or the like along the spraying direction inside the chamber, and a discharge port for discharging the gas inside the chamber. You may do it.

  In the method of the present invention, the material of the substrate on which the droplets are deposited is not particularly limited. For example, it may be a substrate made of an inorganic material such as metal, metal oxide, glass, or silicon, or a substrate made of an organic material such as a polymer material. In addition, any of them may have a layer containing an inorganic material and / or an organic material, and an organic thin film may be formed by depositing droplets on the layer. For example, it may be deposited on an inorganic thin film such as an ITO thin film, or may be deposited on an organic thin film made of PTPDES-2, PEDOT-PSS, TPD, NPD or the like.

The manufacturing method of the present invention is useful for forming a thin film of an organic material (including a complex having an organic molecule as a ligand) that is not suitable for a dry process such as vapor deposition. In particular, materials for organic electronic devices, such as organic semiconductors, organic light emitting materials, organic electron transport materials, and organic hole transport materials, are useful for forming a thin film of such materials because they are hardly soluble organic compounds. It is. In addition, the method of the present invention is particularly useful in the production of organic semiconductor layers, light emitting layers, electron transport layers, electron injection layers, hole transport layers, and hole injection layers of organic electronic devices that require high surface smoothness. Useful.
For example, in an embodiment in which the method of the present invention is used for forming a light emitting layer of an organic EL, an organic compound for a light emitting material and a host material is used as a solute of a raw material. Hereinafter, various compounds that can be used as the solute of the raw material liquid will be described by taking the material for the light emitting layer of the organic EL element as an example.

(I) Luminescent Material As the luminescent material for organic EL, fluorescent luminescent materials and phosphorescent luminescent materials are known. In the manufacturing method of the present invention, any light emitting material can be used as a solute.
(A) Phosphorescent material As a phosphorescent material, generally, a metal complex containing a transition metal atom or a lanthanoid atom can be given.
The transition metal atom preferably includes ruthenium, rhodium, palladium, tungsten, rhenium, osmium, iridium, and platinum, more preferably rhenium, iridium, and platinum, and more preferably iridium, platinum. .
Examples of lanthanoid atoms include lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. Among these lanthanoid atoms, neodymium, europium, and gadolinium are preferable.

Examples of the ligand of the complex include G.I. Wilkinson et al., Comprehensive Coordination Chemistry, Pergamon Press, 1987, H.C. Listed by Yersin, “Photochemistry and Photophysics of Coordination Compounds”, published by Springer-Verlag, 1987, Akio Yamamoto, “Organic Metal Chemistry-Fundamentals and Applications,” published by Soukabo, 1982, etc. .
Specific ligands are preferably halogen ligands (preferably chlorine ligands), aromatic carbocyclic ligands (eg, cyclopentadienyl anion, benzene anion, or naphthyl anion), Nitrogen-containing heterocyclic ligand (eg, phenylpyridine, benzoquinoline, quinolinol, bipyridyl, or phenanthroline), diketone ligand (eg, acetylacetone), carboxylic acid ligand (eg, acetic acid ligand) , Alcoholate ligands (eg, phenolate ligands), carbon monoxide ligands, isonitrile ligands, and cyano ligands, more preferably nitrogen-containing heterocyclic ligands.
The metal complex may have one transition metal atom in the compound, or may be a so-called binuclear complex having two or more.
Different metal atoms may be contained at the same time.

  Among these, specific examples of the light emitting material include, for example, US6303238B1, US6097147, WO00 / 57676, WO00 / 70655, WO01 / 08230, WO01 / 39234A2, WO01 / 41512A1, WO02 / 02714A2, WO02 / 15645A1, WO02 / 44189A1, JP-A No. 2001-247859, JP-A No. 2002-302671, JP-A No. 2002-117978, JP-A No. 2002-225352, JP-A No. 2002-233502, JP-A No. 2003-123982, JP-A No. 2002-170684, EP No. 12122657, JP-A No. 2002-226495 JP, 2002-234894, JP, 2001-247859, JP, 2001-298470, JP, 2002-173673, JP, 2002-20. 678, JP 2002-203679, JP 2004-357791, and the like phosphorescent compounds described in patent documents such as JP-2006-256999.

(B) Fluorescent luminescent materials Fluorescent luminescent dopants generally include benzoxazole, benzimidazole, benzothiazole, styrylbenzene, polyphenyl, diphenylbutadiene, tetraphenylbutadiene, naphthalimide, coumarin, pyran, perinone, oxa Diazole, aldazine, pyralidine, cyclopentadiene, bisstyrylanthracene, quinacridone, pyrrolopyridine, thiadiazolopyridine, cyclopentadiene, styrylamine, aromatic dimethylidin compounds, condensed polycyclic aromatic compounds (anthracene, phenanthroline, pyrene, perylene, Rubrene, pentacene, etc.), 8-quinolinol metal complexes, pyromethene complexes and various metal complexes represented by rare earth complexes, polythiophene, polyphenylene, poly Examples thereof include polymer compounds such as rephenylene vinylene, organic silanes, and derivatives thereof.

(Ii) Host material As a host material of the light emitting layer of an organic EL element, a hole transportable host material and an electron transportable host material are known. In the production method of the present invention, any host material can be used as a solute.
(A) Electron transporting host material The electron transporting host material preferably has an electron affinity Ea of 2.5 eV or more and 3.5 eV or less from the viewpoint of improving durability and lowering driving voltage. More preferably, it is 0.4 eV or less, and further preferably 2.8 eV or more and 3.3 eV or less.
Further, from the viewpoint of improving durability and reducing driving voltage, the ionization potential Ip is preferably 5.7 eV or more and 7.5 eV or less, more preferably 5.8 eV or more and 7.0 eV or less, and 5.9 eV or more. More preferably, it is 6.5 eV or less.
Specific examples of such an electron transporting host include pyridine, pyrimidine, triazine, imidazole, pyrazole, triazole, oxazole, oxadiazol, fluorenone, anthraquinodimethane, anthrone, diphenylquinone, thiol. Pyrandoxide, carbodiimide, fluorenylidenemethane, distyrylpyrazine, fluorine-substituted aromatic compounds, aromatic tetracarboxylic anhydrides such as naphthalene and perylene, phthalocyanines, and their derivatives (form condensed rings with other rings) And metal complexes of 8-quinolinol derivatives, metal phthalocyanines, metal complexes having benzoxazole or benzothiazol as ligands, and the like.

Preferred examples of the electron transporting host include metal complexes, azole derivatives (benzimidazole derivatives, imidazopyridine derivatives, etc.), and azine derivatives (pyridine derivatives, pyrimidine derivatives, triazine derivatives, etc.). Among them, metal complex compounds are preferred from the viewpoint of durability. Is preferred.
The metal complex compound is more preferably a metal complex having a ligand having at least one nitrogen atom, oxygen atom or sulfur atom coordinated to the metal.
The metal ion in the metal complex is not particularly limited, but is preferably beryllium ion, magnesium ion, aluminum ion, gallium ion, zinc ion, indium ion, tin ion, platinum ion, or palladium ion, more preferably beryllium ion, Aluminum ion, gallium ion, zinc ion, platinum ion or palladium ion, and more preferably aluminum ion, zinc ion, platinum ion or palladium ion.

There are various known ligands contained in the metal complex. For example, “Photochemistry and Photophysics of Coordination Compounds”, Springer-Verlag, H.C. Examples include the ligands described in Yersin, published in 1987, “Organometallic Chemistry: Fundamentals and Applications”, Sakai Hanafusa, Yamamoto Akio, published in 1982, and the like.
The ligand is preferably a nitrogen-containing heterocyclic ligand (preferably having 1 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 3 to 15 carbon atoms, and a monodentate ligand. Alternatively, it may be a bidentate or more ligand.
Preferably, it is a bidentate to 6-dentate ligand.
Also preferred are bidentate to hexadentate ligands and monodentate mixed ligands.

  Examples of the ligand include an azine ligand (for example, pyridine ligand, bipyridyl ligand, terpyridine ligand and the like), a hydroxyphenylazole ligand (for example, hydroxyphenylbenzimidazole ligand). , Hydroxyphenylbenzoxazole ligand, hydroxyphenylimidazole ligand, hydroxyphenylimidazopyridine ligand, etc.), alkoxy ligand (preferably having 1 to 30 carbon atoms, more preferably having 1 to 30 carbon atoms). 20, particularly preferably 1 to 10 carbon atoms, such as methoxy, ethoxy, butoxy, 2-ethylhexyloxy, etc.), aryloxy ligands (preferably 6 to 30 carbon atoms, more preferably carbon 6 to 20, particularly preferably 6 to 12 carbon atoms. Shi, 1-naphthyloxy, 2-naphthyloxy, 2,4,6-trimethylphenyl oxy, and 4-biphenyloxy and the like.),

  Heteroaryloxy ligand (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include pyridyloxy, pyrazyloxy, pyrimidyloxy, and quinolyloxy. ), An alkylthio ligand (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methylthio and ethylthio), arylthio ligands (Preferably 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenylthio), heteroarylthio ligand (preferably 1 carbon atom) To 30, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as pyridylthio , 2-benzimidazolylthio, 2-benzoxazolylthio, 2-benzthiazolylthio, etc.), a siloxy ligand (preferably having 1 to 30 carbon atoms, more preferably 3 to 25 carbon atoms). Particularly preferably, it has 6 to 20 carbon atoms, and examples thereof include a triphenylsiloxy group, a triethoxysiloxy group, and a triisopropylsiloxy group.), An aromatic hydrocarbon anion ligand (preferably having 6 carbon atoms) To 30, more preferably 6 to 25 carbon atoms, particularly preferably 6 to 20 carbon atoms, such as a phenyl anion, a naphthyl anion, an anthranyl anion, etc.), an aromatic heterocyclic anion ligand (preferably Has 1 to 30 carbon atoms, more preferably 2 to 25 carbon atoms, and particularly preferably 2 to 20 carbon atoms. Pyrrole anion, pyrazole anion, pyrazole anion, triazole anion, oxazole anion, benzoxazole anion, thiazole anion, benzothiazole anion, thiophene anion, benzothiophene anion, etc.), indolenine anion ligand, etc. , Preferably a nitrogen-containing heterocyclic ligand, aryloxy ligand, heteroaryloxy group, or siloxy ligand, more preferably a nitrogen-containing heterocyclic ligand, aryloxy ligand, siloxy coordination Or an aromatic hydrocarbon anion ligand or an aromatic heterocyclic anion ligand.

  Examples of the metal complex electron transporting host material include, for example, Japanese Patent Application Laid-Open No. 2002-235076, Japanese Patent Application Laid-Open No. 2004-214179, Japanese Patent Application Laid-Open No. 2004-221106, Japanese Patent Application Laid-Open No. 2004-221068, Japanese Patent Application Laid-Open No. 2004-327313, and the like. And the compounds described.

  Specific examples of the electron transporting host material include, but are not limited to, the following materials.

  The electron transport layer host material is preferably E-1 to E-6, E-8, E-9, E-10, E-21, or E-22, and E-3, E-4, E-6. E-8, E-9, E-10, E-21, or E-22 are more preferred, and E-3, E-4, E-8, E-9, E-21, or E-22 are preferred. Further preferred.

(B) Hole transportable host material The hole transportable host material preferably has an ionization potential Ip of 5.1 eV or more and 6.4 eV or less from the viewpoint of improving durability and lowering driving voltage. It is more preferably 6.2 eV or less, and further preferably 5.6 eV or more and 6.0 eV or less.
Further, from the viewpoint of improving durability and lowering driving voltage, the electron affinity Ea is preferably 1.2 eV or more and 3.1 eV or less, more preferably 1.4 eV or more and 3.0 eV or less, and 1.8 eV or more. More preferably, it is 2.8 eV or less.

Specific examples of such a hole transporting host material include the following materials.
Pyrrole, indole, carbazole, azaindole, azacarbazole, pyrazole, imidazole, polyarylalkane, pyrazoline, pyrazolone, phenylenediamine, arylamine, amino-substituted chalcone, styrylanthracene, fluorenone, hydrazone, stilbene, silazane, aromatic tertiary Amine compounds, styrylamine compounds, aromatic dimethylidin compounds, porphyrin compounds, polysilane compounds, poly (N-vinylcarbazole), aniline copolymers, thiophene oligomer thiophene oligomers, conductive polymer oligomers such as polythiophene, organic Examples thereof include silane, carbon film, and derivatives thereof.
Among them, indole derivatives, carbazole derivatives, azaindole derivatives, azacarbazole derivatives, aromatic tertiary amine compounds, and thiophene derivatives are preferable, and indole skeleton, carbazole skeleton, azaindole skeleton, azacarbazole skeleton and / or aromatic are particularly preferable in the molecule. Those having a plurality of group III tertiary amine skeletons are preferred.

  Specific examples of the hole transporting host material include, but are not limited to, the following compounds.

The method for producing a thin film and the method for producing a laminated film of the present invention can be used for producing an organic electronic device such as an organic EL element. Hereinafter, the configuration of an example of an organic EL element that can be produced by the method of the present invention will be described in detail (hereinafter referred to as the organic EL element of the present invention).
The organic EL device of the present invention has a cathode and an anode on a substrate, and has a plurality of organic compound layers including a light emitting layer between both electrodes. Further, an organic compound layer is formed adjacent to both sides of the light emitting layer.
An organic compound layer may be further provided between the organic compound layer adjacent to the light emitting layer and the electrode.
In view of the properties of the light emitting element, at least one of the anode and the cathode is preferably transparent.
Usually, the anode is transparent.
As an aspect of lamination of the organic compound layer in the present invention, an aspect in which a hole transport layer, a light emitting layer, and an electron transport layer are laminated in this order from the anode side is preferable.
Further, a charge blocking layer or the like may be provided between the hole transport layer and the light-emitting layer, or between the light-emitting layer and the electron transport layer.
A preferred embodiment of the organic compound layer in the organic electroluminescence device of the present invention is, in order from the anode side, at least a hole injection layer, a hole transport layer, a light emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer. It is the aspect which has.
When the hole blocking layer is provided between the light emitting layer and the electron transporting layer, the organic compound layer adjacent to the light emitting layer is the hole transporting layer on the anode side and the hole blocking layer on the cathode side. .
Further, a hole injection layer may be provided between the anode and the hole transport layer, and an electron injection layer may be provided between the cathode and the electron transport layer.
Each layer may be divided into a plurality of secondary layers.

<Board>
The substrate of the organic EL element is preferably a substrate that does not scatter or attenuate light emitted from the light emitting layer. Specific examples include zirconia-stabilized yttrium (YSZ), inorganic materials such as glass, polyesters such as polyethylene terephthalate, polybutylene phthalate, and polyethylene naphthalate, polystyrene, polycarbonate, polyethersulfone, polyarylate, polyimide, and polycycloolefin. , Norbornene resins, and organic materials such as poly (chlorotrifluoroethylene).
For example, when glass is used as the substrate, alkali-free glass is preferably used as the material in order to reduce ions eluted from the glass.
Moreover, when using soda-lime glass, it is preferable to use what gave barrier coatings, such as a silica.
In the case of an organic material, it is preferable that it is excellent in heat resistance, dimensional stability, solvent resistance, electrical insulation, and workability.
There is no restriction | limiting in particular about the shape of a board | substrate, a structure, a magnitude | size, It can select suitably according to the use, purpose, etc. of a light emitting element.

In general, the shape of the substrate is preferably a plate shape.
The structure of the substrate may be a single layer structure, a laminated structure, may be formed of a single member, or may be formed of two or more members.
The substrate may be colorless and transparent or colored and transparent, but is preferably colorless and transparent in that it does not scatter or attenuate light emitted from the organic light emitting layer.
The substrate can be provided with a moisture permeation preventing layer (gas barrier layer) on the front surface or the back surface.
As a material for the moisture permeation preventive layer (gas barrier layer), inorganic materials such as silicon nitride and silicon oxide are preferably used. The moisture permeation preventing layer (gas barrier layer) can be formed by, for example, a high frequency sputtering method.
When a thermoplastic substrate is used, a hard coat layer, an undercoat layer, or the like may be further provided as necessary.

<Anode>
The anode usually has a function as an electrode for supplying holes to the organic compound layer, and there is no particular limitation on the shape, structure, size, etc., depending on the use and purpose of the light-emitting element. , Can be appropriately selected from known electrode materials.
As described above, the anode is usually provided as a transparent anode.
Suitable examples of the material for the anode include metals, alloys, metal oxides, conductive compounds, and mixtures thereof.
Specific examples of the anode material include conductive metals such as tin oxide doped with antimony and fluorine (ATO, FTO), tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO). Metals such as oxides, gold, silver, chromium, nickel, and mixtures or laminates of these metals and conductive metal oxides, inorganic conductive materials such as copper iodide and copper sulfide, polyaniline, polythiophene, polypyrrole, etc. Organic conductive materials, and a laminate of these and ITO.
Among these, conductive metal oxides are preferable, and ITO is particularly preferable from the viewpoints of productivity, high conductivity, transparency, and the like.
The anode is composed of, for example, a wet method such as a printing method and a coating method, a physical method such as a vacuum deposition method, a sputtering method, and an ion plating method, and a chemical method such as a CVD and a plasma CVD method. It can be formed on the substrate according to a method appropriately selected in consideration of suitability with the material to be processed.
For example, when ITO is selected as the anode material, the anode can be formed according to a direct current or high frequency sputtering method, a vacuum deposition method, an ion plating method, or the like.
In the organic electroluminescent element of the present invention, the formation position of the anode is not particularly limited and can be appropriately selected according to the use and purpose of the light emitting element.
In this case, the anode may be formed on the entire one surface of the substrate, or may be formed on a part thereof.
The patterning for forming the anode may be performed by chemical etching such as photolithography, or may be performed by physical etching such as laser, or vacuum deposition or sputtering with a mask overlapped. It may be performed by a lift-off method or a printing method.

The thickness of the anode can be appropriately selected depending on the material constituting the anode and cannot be generally defined, but is usually about 10 nm to 50 μm, and preferably 50 nm to 20 μm.
The resistance value of the anode is preferably 10 ³ Ω / □ or less, and more preferably 10 ² Ω / □ or less.
When the anode is transparent, it may be colorless and transparent or colored and transparent.
In order to take out light emission from the transparent anode side, the transmittance is preferably 60% or more, and more preferably 70% or more.
The transparent anode is described in detail in the book “New Development of Transparent Electrode Films” published by CMC (1999), supervised by Yutaka Sawada, and the matters described here can be applied to the present invention.
In the case of using a plastic substrate having low heat resistance, a transparent anode formed using ITO or IZO at a low temperature of 150 ° C. or lower is preferable.

<Cathode>
The cathode usually has a function as an electrode for injecting electrons into the organic compound layer, and there is no particular limitation on the shape, structure, size, etc., depending on the use and purpose of the light-emitting element, It can select suitably from well-known electrode materials.
Examples of the material constituting the cathode include metals, alloys, metal oxides, electrically conductive compounds, and mixtures thereof.
Specific examples include alkali metals (eg, Li, Na, K, Cs, etc.), alkaline earth metals (eg, Mg, Ca, etc.), gold, silver, lead, aluminum, sodium-potassium alloys, lithium-aluminum alloys, magnesium. -Rare earth metals such as silver alloys, indium and ytterbium.
These may be used alone, but two or more can be suitably used in combination from the viewpoint of achieving both stability and electron injection.
Among these, as a material constituting the cathode, an alkali metal or an alkaline earth metal is preferable from the viewpoint of electron injecting property, and a material mainly composed of aluminum is preferable from the viewpoint of excellent storage stability.
The material mainly composed of aluminum is aluminum alone, an alloy of aluminum and 0.01% by mass to 10% by mass of alkali metal or alkaline earth metal, or a mixture thereof (for example, lithium-aluminum alloy, magnesium-aluminum alloy). Etc.).
The cathode materials are described in detail in JP-A-2-15595 and JP-A-5-121172, and the materials described in these publications can also be applied in the present invention.
There is no restriction | limiting in particular about the formation method of a cathode, According to a well-known method, it can carry out.
For example, the cathode described above is configured from a wet method such as a printing method or a coating method, a physical method such as a vacuum deposition method, a sputtering method, or an ion plating method, or a chemical method such as CVD or plasma CVD method. It can be formed according to a method appropriately selected in consideration of suitability with the material.
For example, when a metal or the like is selected as the cathode material, one or more of them can be simultaneously or sequentially performed according to a sputtering method or the like.
Patterning when forming the cathode may be performed by chemical etching such as photolithography, physical etching by laser, or the like, or by vacuum deposition or sputtering with the mask overlaid. It may be performed by a lift-off method or a printing method.
In the present invention, the cathode formation position is not particularly limited, and may be formed on the entire organic compound layer or a part thereof.
Further, a dielectric layer made of an alkali metal or alkaline earth metal fluoride or oxide may be inserted between the cathode and the organic compound layer with a thickness of 0.1 nm to 5 nm.
This dielectric layer can also be regarded as a kind of electron injection layer.
The dielectric layer can be formed by, for example, a vacuum deposition method, a sputtering method, an ion plating method, or the like.
The thickness of the cathode can be appropriately selected depending on the material constituting the cathode and cannot be generally defined, but is usually about 10 nm to 5 μm, and preferably 50 nm to 1 μm.
Further, the cathode may be transparent or opaque.
The transparent cathode can be formed by depositing a thin cathode material to a thickness of 1 nm to 10 nm and further laminating a transparent conductive material such as ITO or IZO.

<Organic compound layer>
The organic compound layer in the present invention will be described.
The organic EL device of the present invention has at least one organic compound layer including a light emitting layer, and other organic compound layers other than the light emitting layer include a hole transport layer, an electron transport layer, a charge blocking layer, a positive block layer, and the like. Examples thereof include a hole injection layer and an electron injection layer. Among these organic compound layers, one or more layers are produced by the production method of the present invention.

-Formation of organic compound layer-
In the organic electroluminescent element of the present invention, each layer constituting the organic compound layer is not limited to the apparatus shown in the present invention, but is a dry film forming method such as a vapor deposition method or a sputtering method, a wet coating method, a transfer method, a printing method, an ink jet method. It can be suitably formed by any method. It is preferably formed by the manufacturing method of the present invention.

-Hole injection layer, hole transport layer-
The hole injection layer and the hole transport layer are layers having a function of receiving holes from the anode or the anode side and transporting them to the cathode side. It is preferably formed by the manufacturing method of the present invention.
The material that can be used for the hole injection layer and the hole transport layer of the present invention is not particularly limited, and may be a low molecular compound or a high molecular compound.
Specifically, pyrrole derivatives, carbazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives , Silazane derivatives, aromatic tertiary amine compounds, styrylamine compounds, aromatic dimethylidin compounds, phthalocyanine compounds, porphyrin compounds, thiophene derivatives, organosilane derivatives, carbon, phenylazole, phenylazine A layer containing a metal complex or the like is preferable.

An electron-accepting dopant can be contained in the hole injection layer or the hole transport layer of the organic EL device of the present invention.
As the electron-accepting dopant introduced into the hole-injecting layer or the hole-transporting layer, an inorganic compound or an organic compound can be used as long as it has an electron-accepting property and oxidizes an organic compound.
Specifically, examples of the inorganic compound include metal halides such as ferric chloride, aluminum chloride, gallium chloride, indium chloride, and antimony pentachloride, metal oxides such as vanadium pentoxide, and molybdenum trioxide.
In the case of an organic compound, a compound having a nitro group, halogen, cyano group, trifluoromethyl group or the like as a substituent, a quinone compound, an acid anhydride compound, fullerene, or the like can be preferably used.
In addition, JP-A-6-212153, JP-A-11-111463, JP-A-11-251067, JP-A-2000-196140, JP-A-2000-286054, JP-A-2000-315580, JP-A-2001-102175, JP-A-2001-2001. -160493, JP2002-252085, JP2002-56985, JP2003-157981, JP2003-217862, JP2003-229278, JP2004-342614, JP2005-72012, JP20051666667 The compounds described in JP-A-2005-209643 and the like can be preferably used.
These electron-accepting dopants may be used alone or in combination of two or more.
Although the usage-amount of an electron-accepting dopant changes with kinds of material, it is preferable that it is 0.01 mass%-50 mass% with respect to hole transport layer material, and it is 0.05 mass%-20 mass%. It is further more preferable and it is especially preferable that it is 0.1 mass%-10 mass%.

The thicknesses of the hole injection layer and the hole transport layer are each preferably 500 nm or less from the viewpoint of lowering the driving voltage.
The thickness of the hole transport layer is preferably 1 nm to 500 nm, more preferably 5 nm to 300 nm, and still more preferably 10 nm to 200 nm.
In addition, the thickness of the hole injection layer is preferably 0.1 nm to 500 nm, more preferably 0.5 nm to 300 nm, and still more preferably 1 nm to 200 nm.
The hole injection layer and the hole transport layer may have a single-layer structure composed of one or more of the materials described above, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions. .

-Electron injection layer, electron transport layer-
The electron injection layer and the electron transport layer are layers having a function of receiving electrons from the cathode or the cathode side and transporting them to the anode side. It is preferably formed by the manufacturing method of the present invention.
The material that can be used for the electron injection layer and the electron transport layer is not particularly limited, and may be a low molecular compound or a high molecular compound.
Specifically, pyridine derivatives, quinoline derivatives, pyrimidine derivatives, pyrazine derivatives, phthalazine derivatives, phenanthroline derivatives, triazine derivatives, triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, fluorenone derivatives, anthraquinodimethane derivatives, anthrone Derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimide derivatives, fluorenylidenemethane derivatives, distyrylpyrazine derivatives, naphthalene, perylene and other aromatic ring tetracarboxylic acid anhydrides, phthalocyanine derivatives, 8-quinolinol derivative metal complexes, Metal phthalocyanines, various metal complexes represented by metal complexes with benzoxazole and benzothiazole as ligands, organosilane derivatives represented by siloles Body, or the like is preferably a layer containing.

The electron injection layer or the electron transport layer of the organic EL device of the present invention can contain an electron donating dopant.
The electron donating dopant introduced into the electron injecting layer or the electron transporting layer only needs to have an electron donating property and a property of reducing an organic compound, such as an alkali metal such as Li or an alkaline earth metal such as Mg. Transition metals including rare earth metals and reducing organic compounds are preferably used.
As the metal, a metal having a work function of 4.2 eV or less can be preferably used. Specifically, Li, Na, K, Be, Mg, Ca, Sr, Ba, Y, Cs, La, Sm, Gd , And Yb.
Examples of the reducing organic compound include nitrogen-containing compounds, sulfur-containing compounds, and phosphorus-containing compounds.
In addition, materials described in JP-A-6-212153, JP-A-2000-196140, JP-A-2003-68468, JP-A-2003-229278, JP-A-2004-342614, and the like can be used.
These electron donating dopants may be used alone or in combination of two or more.
The amount of the electron-donating dopant used varies depending on the type of material, but is preferably 0.1% by mass to 30% by mass, and 0.1% by mass to 20% by mass with respect to the electron transport layer material. Is more preferable, and 0.1% by mass to 10% by mass is particularly preferable.

The thicknesses of the electron injection layer and the electron transport layer are each preferably 500 nm or less from the viewpoint of lowering the driving voltage.
The thickness of the electron transport layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and still more preferably 10 nm to 100 nm.
In addition, the thickness of the electron injection layer is preferably 0.1 nm to 200 nm, more preferably 0.2 nm to 100 nm, and still more preferably 0.5 nm to 50 nm.
The electron injection layer and the electron transport layer may have a single layer structure composed of one or more of the above-described materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions.

-Hall block layer-
The hole blocking layer is a layer having a function of preventing holes transported from the anode side to the light emitting layer from passing to the cathode side. It is preferably formed by the manufacturing method of the present invention.
A hole blocking layer can be provided as an organic compound layer adjacent to the light emitting layer on the cathode side.
Examples of the compound constituting the hole blocking layer include aluminum complexes such as BAlq, triazole derivatives, phenanthroline derivatives such as BCP, and the like.
The thickness of the hole blocking layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and still more preferably 10 nm to 100 nm.
The hole block layer may have a single-layer structure made of one or more of the materials described above, or may have a multilayer structure made up of a plurality of layers having the same composition or different compositions.

-Electronic block layer-
The electron blocking layer is a layer having a function of preventing electrons transported from the cathode side to the light emitting layer from passing through to the anode side. It is preferably formed by the manufacturing method of the present invention.
An electron blocking layer can be provided as the organic compound layer adjacent to the light emitting layer on the anode side.
As examples of the compound constituting the electron blocking layer, for example, those mentioned as the hole transport material described above can be applied.
The thickness of the electron blocking layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and even more preferably 10 nm to 100 nm.
The hole block layer may have a single-layer structure made of one or more of the materials described above, or may have a multilayer structure made up of a plurality of layers having the same composition or different compositions.

<Protective layer>
In the present invention, the entire organic EL element may be protected by a protective layer.
As a material contained in the protective layer, any material may be used as long as it has a function of preventing materials that promote device deterioration such as moisture and oxygen from entering the device.
Specific examples thereof include metals such as In, Sn, Pb, Au, Cu, Ag, Al, Ti, and Ni, MgO, SiO, SiO ₂ , Al ₂ O ₃ , GeO, NiO, CaO, BaO, and Fe ₂ O. ₃ , metal oxides such as Y ₂ O ₃ and TiO ₂ , metal nitrides such as SiN _x and SiN _x O _y , metal fluorides such as MgF ₂ , LiF, AlF ₃ and CaF ₂ , polyethylene, polypropylene, polymethyl Monomer mixture containing methacrylate, polyimide, polyurea, polytetrafluoroethylene, polychlorotrifluoroethylene, polydichlorodifluoroethylene, copolymer of chlorotrifluoroethylene and dichlorodifluoroethylene, tetrafluoroethylene and at least one comonomer A copolymer obtained by copolymerization of a copolymer having a cyclic structure in the copolymer main chain. Copolymer, 1% by weight of the water absorbing water absorption material, water absorption of 0.1% or less of moisture-proof material, and the like.

  The method for forming the protective layer is not particularly limited, and for example, vacuum deposition, sputtering, reactive sputtering, MBE (molecular beam epitaxy), cluster ion beam, ion plating, plasma polymerization (high frequency) Excited ion plating method), plasma CVD method, laser CVD method, thermal CVD method, gas source CVD method, coating method, printing method, transfer method can be applied. Further, the protective layer may be formed by the manufacturing method of the present invention.

<Sealing>
Furthermore, the organic electroluminescent element of this invention may seal the whole element using a sealing container.
Further, a moisture absorbent or an inert liquid may be sealed in a space between the sealing container and the light emitting element.
Although it does not specifically limit as a moisture absorber, For example, barium oxide, sodium oxide, potassium oxide, calcium oxide, sodium sulfate, calcium sulfate, magnesium sulfate, phosphorus pentoxide, calcium chloride, magnesium chloride, copper chloride Cesium fluoride, niobium fluoride, calcium bromide, vanadium bromide, molecular sieve, zeolite, magnesium oxide, and the like.

  The inert liquid is not particularly limited, and examples thereof include paraffins, liquid paraffins, fluorinated solvents such as perfluoroalkane, perfluoroamine, and perfluoroether, chlorinated solvents, and silicone oils. Can be mentioned.

<Drive>
The organic electroluminescence device of the present invention emits light by applying a direct current (which may include an alternating current component as necessary) voltage (usually 2 to 15 volts) or a direct current between the anode and the cathode. Obtainable.
The driving method of the organic electroluminescence device of the present invention is described in JP-A-2-148687, JP-A-6-301355, JP-A-5-29080, JP-A-7-134558, JP-A-8-234658, and JP-A-8-2441047. The driving method described in each publication, Japanese Patent No. 2784615, US Pat. Nos. 5,828,429, 6023308, and the like can be applied.
The light-emitting element of the present invention can improve the light extraction efficiency by various known devices.
For example, by processing the substrate surface shape (for example, forming a fine concavo-convex pattern), controlling the refractive index of the substrate / ITO layer / organic layer, controlling the film thickness of the substrate / ITO layer / organic layer, etc. It is possible to improve light extraction efficiency and external quantum efficiency.
The light emitting element of the present invention may be a so-called top emission type in which light emission is extracted from the anode side.

  In the above description, the configuration of the organic electroluminescent element has been described. However, the method of the present invention can also be used for the production of thin films of other organic electronic devices such as organic solar cells and organic field effect transistors. Moreover, it can utilize also as a preparation method of the thin film for various optical members, such as a reflecting plate and a polarizing plate.

  The features of the present invention will be described more specifically with reference to examples and comparative examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

Using the spray film forming apparatus having the same configuration as in FIG. 1, the raw material liquid is formed into droplets by the two-fluid nozzles 12 a and 12 b, the droplets are concentrated in the chamber 20, and the concentrated droplets are deposited on the substrate 22. The film was formed. The temperature inside the chamber 20 is controlled by the temperature of water flowing through a flow path formed around the outside of the chamber 20.
As the substrate, ITO glass (manufactured by Aldrich, 30-60Ω / □) was used, and after ultrasonic cleaning with a neutral detergent and pure water for about 5 minutes each, water attached to the substrate was removed with a nitrogen blower, Further heating and drying. Then, a solution of PTPDES-2 shown below diluted to 1% by mass with cyclohexanone was spin-coated at a rotation speed of 2000 rpm to obtain a film thickness of 50 nm. This PTPDES-2 functions as a hole transport layer and dissolves in THF.

Next, this glass substrate is set in the substrate holder 24 of the apparatus shown in FIG. The temperature of the water flowing in the chamber 20 and the substrate holder 24 is set to 50 ° C. The opening of the chamber 20 is set to φ10 mm, and the distance from the opening to the substrate 22 is set to 10 mm.
The raw material liquid was diluted with a tetrahydrofuran (THF) solution to the following concentration. Poly [2-methoxy-5- (2-ethylhexyloxy) -1,4-phenylenevinylene] (MEH-PPV, density 0.98 g / cm ³⁾ ) The solution was used. The concentration of the raw material liquid used in each example and comparative example is shown in Table 1.

  The raw material liquid and nitrogen gas are flowed into the two-fluid nozzles 12a and 12b, and the liquid feeding amount is set to 0 to 10 ml / min. The air flow rate is 0 to 10 L / min. The range was changed. In addition, AM-6 manufactured by Atomax is used as the two-fluid nozzles 12a and 12b, Syringe pumps 14a and 14b for adjusting the liquid feeding amount, syringe pumps manufactured by Harvard, and regulators 16a and 16b for adjusting the air flow rate manufactured by Atomax. A regulator was used. The balance of intake and exhaust was set so that the solvent gas concentration in the chamber was 20% LEL or less from the viewpoint of explosion prevention. The spraying time was set to 5 minutes.

Organic thin films were prepared under various conditions shown in the following table.
In Example 1, two nozzles were installed and sprayed with 0.001% by mass and 0.0001% by mass of the raw material liquid, respectively. Moreover, the average droplet diameter at the time of spraying was both set to 5 μm.
In Example 2, two nozzles were installed, and the raw material liquid having the same concentration of 0.001% by mass was sprayed. The average droplet diameter during spraying was set to 5 μm and 3 μm, respectively.
In Example 3, three nozzles were installed and sprayed with the same raw material liquid having the same concentration of 0.001% by mass. The average droplet diameter during spraying was set to 8 μm, 5 μm, and 3 μm, respectively.
Comparative Examples 1-3 sprayed 0.001 mass% of the same raw material liquid with the same average droplet diameter with respect to 1-3 nozzles, respectively.

Each of the produced films was evaluated for light emission unevenness, film density, and adhesion to the lower layer.
The emission unevenness of each film was determined by irradiating the sample with a fluorescent inspection lamp Fi-51L (center wavelength: 350 nm) manufactured by TOPCON and visually confirming the presence or absence of unevenness from the photoluminescence (PL) evaluation (○ : No unevenness, Δ: some unevenness, ×: unevenness on the entire surface).
The film density was evaluated by an X-ray reflectivity measuring apparatus and judged by comparing with the density of MEH-PPV (0.98 g / cm ³ ).
Adhesion to the lower layer was judged from a tape peeling test (◯: not peeled at all, Δ: partly peeled, ×: completely peeled).
The results are shown in the table below.

  From the above results, it can be understood that in the comparative example, the film density is low, uneven light emission occurs, and the adhesion to the substrate is poor. On the other hand, in the examples of the present invention, it can be understood that a thin film having a high film density was produced, and as a result, there was no unevenness in light emission, that is, the device characteristics were improved and the adhesion with the lower layer was further improved.

12a, 12b Two-fluid nozzle 14a, 14b Syringe pump 16a, 16b Regulator 18a, 18b Gas cylinder 20 Chamber 22 Substrate 24 Substrate holder

Claims (11)

Spraying a raw material solution obtained by dissolving and / or dispersing a solute in a solvent to form droplets;
Volatilizing and concentrating the solvent in the droplets;
Depositing concentrated droplets on a substrate or on a thin film provided on the substrate;
A method for producing a thin film sequentially comprising:
A method for producing a thin film, wherein droplets having different droplet diameters are simultaneously deposited on a substrate. 2. The method according to claim 1, wherein raw material liquids having the same solid content composition but different solid content concentrations are sprayed simultaneously from each of the two or more nozzles. The method according to claim 2, wherein the raw material liquids having the same solid content composition but different solid content concentrations are sprayed as droplets having the same diameter. The method according to claim 1, wherein the same raw material liquid is sprayed simultaneously as droplets having different droplet diameters from each of the two or more nozzles. The method according to claim 4, wherein the droplets to be sprayed exhibit a droplet size distribution having two or more peaks. The method according to claim 1, wherein droplets containing at least one kind of solvent that dissolves the material of the substrate or the material of the thin film provided on the substrate are deposited. The raw material liquid contains at least one selected from an organic semiconductor, an organic light emitting material, an organic electron transport material, and an organic hole transport material, according to any one of claims 1 to 6, Method. The method for producing any one of an organic semiconductor layer, a light emitting layer, an electron transport layer, an electron injection layer, a hole transport layer, and a hole injection layer. The method according to item. Producing a single layer thin film of a lower layer of the same solid content composition by the method according to any one of claims 1 to 8;
An upper single-layer thin film having a part or all of a solid content composition different from that of the lower single-layer thin film is formed on the lower single-layer thin film by the method according to any one of claims 1 to 8. thing,
A method for producing a laminated thin film containing at least An apparatus for producing an organic thin film used in the method according to any one of claims 1 to 9,
Droplet forming means having two or more nozzles for forming droplets of a raw material liquid obtained by dissolving and / or dispersing a solute in a solvent;
Raw material liquid supply means for supplying the raw material liquid to the droplet forming means;
Gas supply means for supplying gas to the droplet forming means;
An apparatus for producing a thin film, comprising: a droplet heating unit for heating a droplet provided in connection with the droplet forming unit; and a substrate holder for fixing the substrate. The apparatus according to claim 10, further comprising substrate heating means for heating a substrate provided by connecting the substrate to a holder.

Images