JP2008047428A - Organic electroluminescence element, manufacturing method therefor, lighting device, and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for inexpensively manufacturing an organic EL element that has a high luminous efficiency and a longer service lifetime, to provide the organic EL element manufactured by the manufacturing method, to provide a lighting device, and to provide a display device. <P>SOLUTION: The manufacturing method is used for manufacturing the organic EL element that has at least a positive electrode and a negative electrode on a support substrate, and also, has organic layers including at least one luminous layer between the positive electrode and the negative electrode. A film thickness T(EM) (nm) of the luminous layer satisfies a relational expression (1): 40 nm<T(EM)≤100 nm. At least one luminous layer includes a phosphorescence emission material. The manufacturing method has a step for forming at least one layer of the organic layers by laminating a layer A and a layer B. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an organic electroluminescence element, an organic electroluminescence element, a lighting device, and a display device.

  An organic electroluminescence element (hereinafter also referred to as an organic EL element) is an all-solid-state element composed of an organic material film having a thickness of only about 0.1 μm between electrodes, and its light emission is about 2V to 20V. Therefore, this technology is expected as a next-generation flat display and illumination.

  In addition, recently discovered organic EL devices that use phosphorescence can realize a luminous efficiency that is approximately four times that of previous devices that use fluorescence. Research and development of light-emitting element layer configurations and electrodes are performed all over the world.

  In addition, the structure of the organic EL element is a simple one in which an organic layer is sandwiched between a transparent electrode and a counter electrode, and the number of parts is overwhelmingly smaller than that of a liquid crystal display, which is a typical flat display. Although the cost should be kept low, this is not always the case at present, and a large amount of water is drained from the liquid crystal display in terms of performance and cost. In particular, in terms of cost, poor productivity is considered as a factor.

Most of the organic EL devices that are currently commercialized are manufactured by a so-called vapor deposition method in which a low molecular material is deposited to form a film. In this vapor deposition method, an organic EL material can be used as a low-molecular compound that can be easily purified (it is easy to obtain a high-purity material), and it is easy to make a laminated structure. However, since deposition is performed under a high vacuum condition of 10 ⁻⁴ Pa or less, restrictions are imposed on the film forming apparatus, and in fact, it can be applied only to a substrate with a small area. Then, there is a problem that the film formation takes time and the throughput is low. In particular, it becomes a problem when applied to lighting applications and large-area electronic displays, and organic EL elements are one of the causes that are not practically used in such applications.

  On the other hand, in the polymer system, the organic compound layer of the organic EL element can be produced by a coating process such as spin coating, inkjet, printing, spraying.

  Since this can be manufactured under atmospheric pressure, the cost can be reduced. At the same time, when forming an organic layer of an organic EL element, a necessary material (a high molecular material and / or a low molecular material) is used. ) Is prepared and applied in a thin film, so multiple organic materials can be mixed precisely (for example, it is easy to adjust dopants for the light-emitting host material, etc.), and uneven light emission can be achieved even if the device is enlarged. Although it is difficult, and it is very advantageous in terms of manufacturing cost, the counter electrode formed after forming an organic layer in a general manufacturing process is produced by a vacuum process such as vapor deposition or sputtering. After all, that process has become a bottleneck and cannot be an innovative production process.

  In contrast to the vapor deposition system, the purity of the polymer material cannot be increased and it is difficult to stack the layers, so that the light emission performance is not as good as the vapor deposition system, and it is practically used. There is also a problem of not.

The above is the difference in the manufacturing method mainly attributed to the material, but when focusing on the method of forming the element itself,
(A) a method of sequentially forming a thin film on an electrode substrate (sequential film forming method);
(B) There is a method (bonding method) in which a thin film is appropriately formed on an electrode substrate and a counter electrode substrate and then bonded.

The advantage of the bonding method is
(1) In the sequential film formation method, the counter electrode to be finally formed can be prepared in advance.
(2) Use of a film for the substrate enables continuous production in a roll-to-roll system,
(3) The organic layer can be easily stacked if the bonding surfaces are organic layers,
Etc.

  In particular, (1) and (2) will be a driving force for dramatically improving productivity, and if the technology is completed, it will be possible to greatly reduce the manufacturing cost, which was the biggest problem of organic EL. It is. On the other hand, the roll-to-roll method is disclosed in a technique other than the bonding method.

  For example, a method is described in which a hole transport material is continuously formed on an electrode substrate wound in a ribbon shape on a reel by an ink jet method (see, for example, Patent Document 1). As described in the coating method, since the formation of the counter electrode eventually becomes a vacuum process, the merit of the roll-to-roll method is greatly reduced, and there is a problem that the productivity is not substantially improved.

  As described above, the bonding method is an effective technical means for innovatively improving the productivity, but at present, the organic EL device manufactured by this method has a problem in performance and is accurate. The breakthrough has not been found and is in the process of development.

  There are several reasons for this, but considering the principle, the bonding surface when bonded is not necessarily in close contact at the molecular level, and as a result, the carrier movement is not smooth, and the bonding surface is easy to peel off and emit light. It is expected that there may be a problem such as a case where the device does not function as an element.

  In particular, since the roll-to-roll method has the same winding process as the roll-to-roll method, peeling is likely to occur at that time, which is a major problem in manufacturing, and the substrate is flexible such as a film or plastic substrate. When used as a base material, there is a problem that it becomes a fatal defect that the element is destroyed at the time of use.

  From such a viewpoint, several techniques for improving the bonding failure at the time of bonding are disclosed.

  For example, by making both bonding layers made of the same material, a technique for improving the adhesion between the layers (see, for example, Patent Document 2), or a method in which two bonding surfaces are completely manufactured by a wet method. Although the technique (for example, refer patent document 3) which bonds the film | membrane of the state which is not dried is introduced, the adhesiveness in a joint surface is inadequate and is not a fundamental solution. .

  In addition, a technique for improving the adhesion of the bonding surface by allowing a polymer binder to exist on the bonding surface and bonding or fusing the periphery of the element (for example, see Patent Document 4) is a similar technique. It is described that the idea can be applied to phosphorescence emission in combination with a technique for forming a light emitting layer by a transfer method (see, for example, Patent Document 5).

  Adhering the surroundings contributes to reducing the adverse effects of moisture and oxygen during device operation and improving the light emission lifetime, but it cannot be a technical means that can fundamentally solve the peeling of the joint surface. There is a point.

  Moreover, peeling of the thin film interface is not a problem only by the bonding method.

  The organic EL elements that are currently commercialized are all non-flexible light-emitting elements in which glass is used as a substrate. As described above, organic EL elements that are all solid elements are flexible films such as films. A major feature is that it can be applied to a certain substrate (so-called flexible display).

  At present, it is said that the inadequate gas barrier property of the flexible base material delays its practical application, but as another issue, peeling between the organic layer and the counter electrode layer is also a major issue It is.

  Although this issue is an inflexible element at present, it has not been taken up as an obvious issue. However, in principle, the adhesion between the organic substance and the metal forming the counter electrode is low, which is a fundamental issue. .

  Further, in a sequential film forming method that is usually applied, after forming an organic layer such as a light emitting layer or a carrier transport / injection layer, a counter electrode (usually a cathode, specifically, a work such as Al, Ca, Ba, etc.). However, if the organic layer that has already been formed is damaged, the emission characteristics and lifetime of the organic EL element will be greatly degraded. There is.

  In other words, it is impossible to form the counter electrode in a strong energy state in order to increase the adhesion between the counter electrode and the organic layer interface. In practice, the film is formed by vacuum deposition or sputtering under mild conditions. There is nothing but a situation.

  As means for solving this problem, a technique of providing a buffer layer made of a semiconductor material or a metal on an organic layer closest to the counter electrode is disclosed (for example, see Patent Document 6 and Patent Document 7).

  Although it is possible to reduce the damage at the time of film formation of the counter electrode by interposing such a buffer layer, it is absolutely preferable from the viewpoint of productivity because the load increases in the manufacturing process. It is not a thing.

  On the other hand, as a countermeasure for improving the light emission efficiency and extending the life of organic EL elements using phosphorescence, the element structure can be multilayered. In the coating method, the lower layer is formed by a coating solution solvent on the upper layer of the organic layer. It is extremely difficult to form a plurality of organic layers by laminating the surface of the film and disturbing the underlying film.

  On the other hand, a technique is disclosed in which the upper layer material is dissolved in a solvent outside the solubility range of the solubility parameter of the lower layer main material, and the lower layer thin film surface is not disturbed (see, for example, Patent Document 8). .)

  Also, the solvent (poor solvent) outside the solubility range of the solubility parameter of the lower layer main material is dissolved in the mixed solvent of the solvent (good solvent) and the poor solvent within the solubility range of the solubility parameter, and the solubility is increased. A technique for dropping and stacking is disclosed (for example, see Patent Document 9).

However, an element having three or more organic layers having a functional layer such as a hole transport layer or an electron transport layer before and after a light emitting layer optimum for an organic EL element using phosphorescence is manufactured by the above-described method. If it tries to do it, the restrictions of organic EL element material will increase drastically, it will be difficult to apply to arbitrary organic EL materials, and there will be a problem that the merit of original multilayering will be lost.
JP 2005-327667 A JP 2002-203675 A JP-A-9-306667 JP-A-9-7736 JP 2004-79300 A Japanese Patent Laying-Open No. 2005-243411 JP 2005-183013 A JP 2002-299061 A JP 2005-259523 A

  An object of the present invention is to provide a production method for producing an organic electroluminescence element having a high luminous efficiency and a long lifetime at a low cost, and an organic electroluminescence element, an illumination device and a display device produced by the production method Is to provide.

  The above object of the present invention has been achieved by the following configurations 1 to 9.

1. In a method for producing an organic electroluminescent device having at least an anode and a cathode on a support substrate, and having an organic layer including at least one light emitting layer between the anode and the cathode,
The total film thickness T (EM) (nm) of the light emitting layer satisfies the following relational expression (1), at least one of the light emitting layers has a phosphorescent material, and at least one of the organic layers is: The manufacturing method of the organic electroluminescent element characterized by having the process formed by bonding of the layer A and the layer B.

Relational expression (1)
40 nm <T (EM) ≦ 100 nm
2. 2. The method for producing an organic electroluminescent element according to 1 above, wherein the organic layer has three or more layers.

  3. 3. The method for producing an organic electroluminescent element according to 1 or 2, wherein the layer A and the layer B each contain a compound having the same structure as a main component.

  4). Either of the said layer A or the said layer B contains a phosphorescence-emitting material, The manufacturing method of the organic electroluminescent element of any one of said 1-3 characterized by the above-mentioned.

  5. 4. The method for producing an organic electroluminescent element according to any one of 1 to 3, wherein the layer A and the layer B each contain a phosphorescent material.

  6). The method for producing an organic electroluminescent element according to any one of 1 to 5, wherein the phosphorescent material is an iridium complex or a platinum complex.

  7). 7. An organic electroluminescence device produced by the method for producing an organic electroluminescence device according to any one of 1 to 6 above.

  8). 8. An illuminating device comprising the organic electroluminescence element as described in 7 above.

  9. 8. A display device comprising the organic electroluminescence element as described in 7 above.

  According to the present invention, there is provided a manufacturing method for manufacturing an organic electroluminescence element having high luminous efficiency and a long lifetime at low cost, and an organic electroluminescence element, an illumination device, and a display device manufactured by the manufacturing method are provided. We were able to.

  In the manufacturing method of the organic electroluminescent element of this invention, by having the structure of any one of Claims 1-6, the organic electroluminescent element with high luminous efficiency and long life is manufactured at low cost. A manufacturing method was provided, and an organic electroluminescence element, a lighting device, and a display device produced by the manufacturing method could be provided.

  Hereinafter, details of each component according to the present invention will be sequentially described.

<< Method for Manufacturing Organic Electroluminescent Element >>
The manufacturing method of the organic electroluminescent element of this invention is demonstrated.

  According to the method for producing an organic electroluminescent element of the present invention, an organic layer having at least an anode and a cathode on a support substrate and including at least one light emitting layer between the anode and the cathode is provided. In the manufacturing method of the organic electroluminescence element having, the film thickness T (EM) (nm) of the light emitting layer satisfies the following relational expression (1), at least one of the light emitting layers has a phosphorescent light emitting material, and It is characterized in that at least one layer of the organic layer is formed by laminating layer A and layer B.

<< Light emitting layer thickness T (EM) >>
The film thickness T (EM) of the light emitting layer according to the present invention represents the following relational expression (1).

  In order to obtain the effects described in the present invention, the film thickness T (EM) of at least one light emitting layer of the constituent layers of the organic EL element of the present invention must satisfy the relational expression (1). From the viewpoint of reducing the light emission starting voltage of the organic EL device of the invention, increasing the power saving effect, reducing the non-light emitting point of the light emitting layer, and reducing the occurrence of uneven light emission, the following relational expression (2) It is preferable to satisfy | fill the relational expression represented by these.

Relational expression (1)
40 nm <T (EM) ≦ 100 nm
Relational expression (2)
45 nm <T (EM) ≦ 100 nm
<Structure of organic layer>
The organic layer according to the present invention is preferably three or more layers, and at least one of the organic layers is formed by bonding with the layer A and the layer B. Each preferably contains a compound having the same structure as the main component.

  Moreover, it is preferable from a viewpoint of the element characteristic improvement of the organic EL element of this invention that either the said layer A or the said layer B contains a phosphorescence-emitting material. The phosphorescent material is also described in detail in the constituent layers of the organic EL element described later.

<< Structure of organic layer and film thickness T (EM) of total light emitting layer >>
In particular, when layer A is a light-emitting film, layer B is a light-emitting film, and at least one light-emitting layer is formed by bonding of layer A and layer B, for example, an anode such as ITO described later When layer B is provided on a cathode-side substrate (also referred to as cathode-side member) such as layer A and Al on the side substrate (also referred to as anode-side member) (note that layer A is provided on the cathode-side substrate) Layer B may be provided on the anode side substrate),
Both the film thickness of layer A on the anode side substrate and the film thickness of layer B on the cathode side substrate exceed 20 nm,
Moreover, it is preferable that the total light emitting layer thickness T (EM) satisfies the relational expression of 40 nm <T (EM) ≦ 100 nm.

From the viewpoint of uneven light emission, when the thickness of the organic layer (also referred to as organic compound layer) is T (org) and the total light emitting layer is T (EM), from the viewpoint of suppressing uneven light emission,
It is preferable that the relational expression of 0.3 ≦ T (EM) / T (org) ≦ 0.8 is satisfied.

<< Formation of organic EL element component layer by bonding method (also simply referred to as bonding) >>
The formation process of the structural layer of the organic EL element by the bonding which concerns on this invention is demonstrated.

  Since the bonding is performed after all the layers necessary for the configuration of the organic EL element are formed in advance (for example, an anode side substrate, a cathode side substrate, etc.), a transparent electrode (an anode side substrate such as ITO) The counter electrode (a cathode-side substrate such as Al) is formed first.

  When depositing a metal or metal oxide, it is desirable to apply high energy during deposition or after deposition to make a film with good performance, but the bonding method is one means that makes it possible. You can think of it.

  In other words, if the bonding surfaces for bonding are organic layers, the transparent electrode and the counter electrode can be formed in advance by a method most suitable in terms of performance and productivity, respectively.

  On top of that, if an organic layer is appropriately laminated and bonded, it is an innovative method that is good in terms of performance and manufacturing process as long as the defect on the joint surface is improved.

<Adaptability of phosphorescence method>
As a problem of the bonding method, the problem on the joint surface was mentioned earlier. As a result of diligent investigation on this problem, for example, when organic layers are bonded together, the carrier movement at the bonding interface is not uniform over the entire surface, and it is easy to create a portion where carriers can flow locally and a portion where flow is difficult I understand.

  In particular, it has been found that the fluorescence method of emitting light at the interface of the organic layer has a remarkable behavior, and uneven light emission is likely to occur.

  On the other hand, the phosphorescence method, unlike the fluorescence method, has a light emitting region inside the light emitting layer, so this phenomenon is relatively difficult to occur.In particular, the relative film thickness ratio of the entire organic layer of the light emitting layer is set. When increasing the thickness, increasing the thickness of the light-emitting layer, or when using two light-emitting layers that join the light-emitting layers together, it is understood that light emission unevenness can be suppressed to the extent that even microscopic observation does not reveal it. It was.

  This is a technology that effectively utilizes the phenomenon of slow carrier movement at the bonding interface, which is the biggest difficulty of the bonding method, and can be said to be an epoch-making discovery that has never been seen before. .

  A constituent layer of an organic EL element using a bonding method (particularly, formation of an organic layer (organic compound layer)) is a very effective means for solving such a problem.

  As a result of the examination, as a factor giving an organic EL element with high luminous efficiency and long life, the above-mentioned “use of phosphorescence emission, multilayering of elements (having a plurality of organic layers for separating functions)” At the same time, it has been found that the thickness of the light emitting layer of the device is an important factor.

  In particular, when the relative film thickness ratio of the entire organic layer of the light emitting layer is increased, or when the film thickness of the light emitting layer is increased, the light emitting layers are joined together, that is, two light emitting layers are combined into one layer. When the light emitting layer was used, it was found that it was possible to produce an organic EL device with high emission efficiency by suppressing unevenness of light emission so that it could not be seen by microscopic observation.

<< Formation method of organic layers other than bonding >>
The method for producing an organic EL device of the present invention is a method in which at least one organic layer as a constituent layer is bonded to a layer A provided on the anode substrate side and a layer B provided on the cathode substrate side. It is characterized in that an EL element is manufactured.

  The constituent layer of the organic EL element will be described in detail in the constituent layer of the organic EL element to be described later. For example, as a constituent example of the organic EL element, an anode / hole injection layer / hole transporting layer / light emitting layer For example, an organic EL element composed of / electron transport layer / electron injection layer / cathode will be described. The layer formed by bonding layer A and layer B includes a hole injection layer, a hole transport layer, a light emitting layer, Either an electron transport layer or an electron injection layer may be used.

  Moreover, conventionally well-known coating methods, methods, such as vapor deposition, sputtering, etc. can be used suitably except the organic layer formed by bonding, Of course, it is also possible to use together the bonding method suitably.

  As a method for forming each layer of the organic layer other than the bonding method, there are a vapor deposition method, a wet process (spin coating method, casting method, ink jet method, printing method) as described above, and it is easy to obtain a homogeneous film, and In the present invention, film formation by a coating method such as a spin coating method, an ink jet method, or a printing method is preferable from the viewpoint that pinholes are hardly generated.

  Examples of the liquid medium for dissolving or dispersing the organic EL material used for forming the organic layer include ketones such as methyl ethyl ketone and cyclohexanone, fatty acid esters such as ethyl acetate, halogenated hydrocarbons such as dichlorobenzene, toluene, Aromatic hydrocarbons such as xylene, mesitylene and cyclohexylbenzene, aliphatic hydrocarbons such as cyclohexane, decalin and dodecane, and organic solvents such as DMF and DMSO can be used. Moreover, as a dispersion method, it can disperse | distribute by dispersion methods, such as an ultrasonic wave, high shear force dispersion | distribution, and media dispersion | distribution.

<< Constituent layers of organic EL elements >>
The constituent layers of the organic EL element of the present invention will be described. In this invention, although the preferable specific example of the layer structure of an organic EL element is shown below, this invention is not limited to these.
(I) Anode / light emitting layer / electron transport layer / cathode (ii) Anode / hole transport layer / light emitting layer / electron transport layer / cathode (iii) Anode / hole transport layer / light emitting layer / hole blocking layer / electron Transport layer / cathode (iv) anode / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode (v) anode / anode buffer layer / hole transport layer / light emitting layer / hole Blocking layer / electron transport layer / cathode buffer layer / cathode In the organic EL device of the present invention, the blue light emitting layer preferably has a light emission maximum wavelength of 430 nm to 480 nm, and the green light emitting layer has a light emission maximum wavelength of 510 nm to 550 nm, The red light emitting layer is preferably a monochromatic light emitting layer having a light emission maximum wavelength in the range of 600 nm to 640 nm, and is preferably a display device using these. Alternatively, a white light emitting layer may be formed by laminating at least three light emitting layers. Further, a non-light emitting intermediate layer may be provided between the light emitting layers. The organic EL element of the present invention is preferably a white light emitting layer, and is preferably a lighting device using these.

  Each layer which comprises the organic EL element of this invention is demonstrated.

<Light emitting layer>
The light emitting layer according to the present invention is a layer that emits light by recombination of electrons and holes injected from the electrode, the electron transport layer, or the hole transport layer, and the light emitting portion is in the layer of the light emitting layer. May be the interface between the light emitting layer and the adjacent layer.

  The total film thickness of the light emitting layer is not particularly limited, but from the viewpoint of improving the uniformity of the film, preventing unnecessary application of high voltage during light emission, and improving the stability of the emission color with respect to the drive current. It is preferable to adjust in the range of 2 nm to 5 μm, more preferably in the range of 2 nm to 200 nm, and particularly preferably in the range of 10 nm to 20 nm.

  For the production of the light-emitting layer, a light-emitting dopant or a host compound, which will be described later, is formed and formed by a known thinning method such as a vacuum deposition method, a spin coating method, a casting method, an LB method, or an ink-jet method. it can.

  The light emitting layer of the organic EL device of the present invention preferably contains a light emitting host compound and at least one kind of light emitting dopant (such as a phosphorescent dopant (also referred to as a phosphorescent dopant) or a fluorescent dopant).

(Host compound (also called luminescent host))
The host compound used in the present invention will be described.

  Here, the host compound in the present invention is a phosphorescent quantum yield of phosphorescence emission at a room temperature (25 ° C.) having a mass ratio of 20% or more in the compound contained in the light emitting layer. Is defined as a compound of less than 0.1. The phosphorescence quantum yield is preferably less than 0.01. Moreover, it is preferable that the mass ratio in the layer is 20% or more among the compounds contained in a light emitting layer.

  As the host compound, known host compounds may be used alone or in combination of two or more. By using a plurality of types of host compounds, it is possible to adjust the movement of charges, and the organic EL element can be made highly efficient. Moreover, it becomes possible to mix different light emission by using multiple types of light emission dopants mentioned later, and can thereby obtain arbitrary luminescent colors.

  The light emitting host used in the present invention may be a conventionally known low molecular compound or a high molecular compound having a repeating unit, and a low molecular compound having a polymerizable group such as a vinyl group or an epoxy group (deposition polymerization property). Light emitting host).

  As a known host compound that may be used in combination, a compound that has a hole transporting ability and an electron transporting ability, prevents the emission of light from being increased in wavelength, and has a high Tg (glass transition temperature) is preferable.

  Specific examples of known host compounds include compounds described in the following documents.

  JP-A-2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, 2002-8860, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645, 2002-338579, 2002-105445 gazette, 2002-343568 gazette, 2002-141173 gazette, 2002-352957 gazette, 2002-203683 gazette, 2002-363227 gazette, 2002-231453 gazette, No. 003-3165, No. 2002-234888, No. 2003-27048, No. 2002-255934, No. 2002-286061, No. 2002-280183, No. 2002-299060, No. 2002. -302516, 2002-305083, 2002-305084, 2002-308837, and the like.

  Hereinafter, although the specific example of the compound preferably used as a host compound of the light emitting layer of the organic EL element of this invention is given, this invention is not limited to these.

  Moreover, although the reactive host compound shown below is preferably used for formation of a light emitting layer, this invention is not limited to these.

  Moreover, as a reactive host compound, the compound which has the reactive group shown below to a conventionally well-known host compound is also used preferably.

(Luminescent dopant)
The light emitting dopant according to the present invention will be described.

  As the light-emitting dopant according to the present invention, a fluorescent dopant (also referred to as a fluorescent compound) or a phosphorescent dopant (also referred to as a phosphorescent emitter, a phosphorescent compound, a phosphorescent compound, or the like) can be used. From the viewpoint of obtaining an organic EL device with high luminous efficiency, the light emitting dopant used in the light emitting layer or the light emitting unit of the organic EL device of the present invention (sometimes simply referred to as a light emitting material) contains the above host compound. At the same time, it is preferable to contain a phosphorescent dopant.

(Phosphorescent dopant)
The phosphorescent dopant according to the present invention will be described.

  The phosphorescent dopant according to the present invention is a compound in which light emission from an excited triplet is observed. Specifically, the phosphorescent dopant is a compound that emits phosphorescence at room temperature (25 ° C.) and has a phosphorescence quantum yield of 25. Although it is defined as a compound of 0.01 or more at ° C., a preferable phosphorescence quantum yield is 0.1 or more.

  The phosphorescence quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of Experimental Chemistry Course 4 of the 4th edition. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescence dopant according to the present invention achieves the phosphorescence quantum yield (0.01 or more) in any solvent. That's fine.

  There are two types of light emission of phosphorescent dopants in principle. One is the recombination of carriers on the host compound to which carriers are transported to generate an excited state of the host compound, and this energy is transferred to the phosphorescent dopant. The energy transfer type that obtains light emission from the phosphorescent dopant, and the other is that the phosphorescent dopant becomes a carrier trap, carrier recombination occurs on the phosphorescent dopant, and light emission from the phosphorescent dopant is obtained. Although it is a trap type, in any case, the excited state energy of the phosphorescent dopant is required to be lower than the excited state energy of the host compound.

  The phosphorescent dopant can be appropriately selected from known materials used for the light emitting layer of the organic EL device.

  The phosphorescent dopant according to the present invention is preferably a complex compound containing a group 8-10 metal in the periodic table, more preferably an iridium compound, an osmium compound, or a platinum compound (platinum complex compound). Rare earth complexes, most preferably iridium compounds.

  Although the specific example of the compound used as a phosphorescence dopant below is shown, this invention is not limited to these. These compounds are described, for example, in Inorg. Chem. 40, 1704-1711, and the like.

  Moreover, although the reactive phosphorescent dopant shown below is preferably used for formation of a light emitting layer, this invention is not limited to these.

  Moreover, as a reactive phosphorescent dopant, the compound which substituted the reactive group which said reactive host compound may have into the conventionally well-known phosphorescent compound is also used preferably.

  As the phosphorescent dopant (also referred to as phosphorescent compound, phosphorescent compound, etc.) according to the present invention, the blue light-emitting ortho as described below is used as a so-called blue light-emitting dopant in which the emission from the excited triplet is blue. Metal complexes are preferably used.

《Dendrimer type phosphorescent organometallic complex》
Moreover, as a phosphorescence dopant which concerns on this invention, the dendrimer type phosphorescence-emitting organometallic complex represented by the following general formula (D1) can be used.

General formula (D1)
P-[(Dendron) m] n
In the general formula (D1), dendron represents a dendritic molecule represented by the following general formula (E), n represents an integer greater than 0, m represents an integer greater than 0 and less than n. To express. P represents a phosphorescent organometallic complex that serves as a core.

  General formula (E)

  In the general formula (E), Ar represents a trivalent group derived from an aromatic hydrocarbon ring or an aromatic heterocyclic ring. Represents an aromatic heterocycle, and X represents a single bond or a divalent linking group that binds to the phosphorescent organometallic complex P, which serves as the core. n represents the number of branches (also referred to as the number of generations).

  In the general formula (E), the aromatic hydrocarbon ring represented by Ar includes a benzene ring, a biphenyl ring, a naphthalene ring, an azulene ring, an anthracene ring, a phenanthrene ring, a pyrene ring, a chrysene ring, a naphthacene ring, a triphenylene ring, o-terphenyl ring, m-terphenyl ring, p-terphenyl ring, acenaphthene ring, coronene ring, fluorene ring, fluoranthrene ring, naphthacene ring, pentacene ring, perylene ring, pentaphen ring, picene ring, pyrene ring, Examples include a pyranthrene ring and anthraanthrene ring. In addition, these rings may further have a substituent represented by R in the general formula (A).

  In the general formula (E), examples of the aromatic heterocycle represented by Ar include a furan ring, a thiophene ring, an oxazole ring, a pyrrole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, and a benzimidazole. Ring, oxadiazole ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indazole ring, indazole ring, benzimidazole ring, benzothiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring, cinnoline ring, quinoline ring, isoquinoline Ring, phthalazine ring, naphthyridine ring, carbazole ring, carboline ring, diazacarbazole ring (showing a ring in which one of the carbon atoms of the hydrocarbon ring constituting the carboline ring is further substituted with a nitrogen atom).

  These rings may further have a substituent. Examples of the substituent include alkyl groups (for example, methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group). Group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group etc.), cycloalkyl group (eg cyclopentyl group, cyclohexyl group etc.), alkenyl group (eg vinyl group, allyl group etc.), alkynyl group (eg , Ethynyl group, propargyl group, etc.), aryl group (eg, phenyl group, naphthyl group, etc.), aromatic heterocyclic group (eg, furyl group, thienyl group, pyridyl group, pyridazinyl group, pyrimidinyl group, pyrazinyl group, triazinyl group) Imidazolyl group, pyrazolyl group, thiazolyl group, quinazolinyl group, carbazolyl group, cal A linyl group, a diazacarbazolyl group (in which one of carbon atoms constituting the carboline ring of the carbolinyl group is replaced with a nitrogen atom), a phthalazinyl group, etc.), a heterocyclic group (for example, a pyrrolidyl group, Imidazolidyl group, morpholyl group, oxazolidyl group, etc.), alkoxy group (for example, methoxy group, ethoxy group, propyloxy group, pentyloxy group, hexyloxy group, octyloxy group, dodecyloxy group, etc.), cycloalkoxy group (for example, Cyclopentyloxy group, cyclohexyloxy group, etc.), aryloxy group (eg, phenoxy group, naphthyloxy group, etc.), alkylthio group (eg, methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group) Etc.), Cycloa Kirthio group (eg, cyclopentylthio group, cyclohexylthio group, etc.), arylthio group (eg, phenylthio group, naphthylthio group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyl) Oxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (eg, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), sulfamoyl group (eg, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butyl) Aminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, Naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), acyl group (for example, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group) , Phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy group (for example, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.) Amide group (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group) Cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc.), carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylamino) Carbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group Etc.), ureido group (for example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, Cutylureido group, dodecylureido group, phenylureido group naphthylureido group, 2-pyridylaminoureido group, etc.), sulfinyl group (for example, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecyl) Sulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group, etc.), alkylsulfonyl group (for example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group) Etc.), arylsulfonyl group or heteroarylsulfonyl group (for example, phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfur group) Phonyl group, etc.), amino group (for example, amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, naphthylamino group, 2-pyridylamino group) Etc.), halogen atoms (eg fluorine atom, chlorine atom, bromine atom etc.), fluorinated hydrocarbon groups (eg fluoromethyl group, trifluoromethyl group, pentafluoroethyl group, pentafluorophenyl group etc.), cyano group Nitro group, hydroxy group, mercapto group, silyl group (for example, trimethylsilyl group, triisopropylsilyl group, triphenylsilyl group, phenyldiethylsilyl group, etc.). These substituents may be further substituted with the above substituents. In addition, a plurality of these substituents may be bonded to each other to form a ring.

  In the general formula (E), examples of the divalent linking group represented by X include hydrocarbon groups such as alkylene groups, alkenylene groups, alkynylene groups, and arylene groups, as well as the alkylene groups, the alkenylene groups, and the alkynylene groups. In the arylene group, each of them may contain a hetero atom (for example, a nitrogen atom, a sulfur atom, a silicon atom, etc.), or a thiophene-2,5-diyl group or pyrazine-2,3-diyl. It may be a divalent linking group derived from a compound having an aromatic heterocycle such as a group (also referred to as a heteroaromatic compound), or a chalcogen atom such as oxygen or sulfur. Further, it may be a group such as an alkylimino group, a dialkylsilanediyl group, or a diarylgermandiyl group that connects and connects heteroatoms.

  Hereinafter, although the specific example of a dendrimer represented by general formula (D1) is shown, this invention is not limited to these.

<Cyclodextrin derivative>
As the phosphorescent dopant according to the present invention, a cyclodextrin derivative represented by the following general formula (D) can be used. Here, the cyclodextrin derivative is a general term for compounds having a structure in which a plurality of D-glucopyranose groups are cyclized by α-1,4 glycosidic bonds. The primary and secondary hydroxyl groups present in the molecule may be substituted with a substituent.

  In the general formula (D), R represents a substituent, and Z represents a residue of the phosphorescent compound.

  In the general formula (D), the substituent represented by R has the same meaning as the substituent that the aromatic hydrocarbon ring represented by Ar in the general formula (E) may have.

  In the general formula (D), as the phosphorescent compound used as a residue of the phosphorescent compound represented by Z, a phosphorescent compound (also referred to as a phosphorescent dopant) can be used.

  Hereinafter, although the preferable specific example of the cyclodextrin derivative used for this invention is shown, this invention is not limited to these.

  In CD-1 and 2, Ac represents an acetyl group.

《Calixarene derivative》
The calixarene derivative used as a kind of phosphorescent dopant according to the present invention will be described.

  The calixarene derivative used in the present invention is a general term for compounds having a cyclic structure in which a phenol derivative is bonded with an alkylene group or an oxyalkylene group, as represented by the following general formula (A). The phenolic hydroxyl group may be substituted with a substituent.

  In the general formula (A), the divalent linking group represented by A and L has the same meaning as the divalent linking group represented by X in the general formula (E).

  Furthermore, examples of the divalent linking group represented by A and L include, for example, a carbazole ring, a carboline ring, a diazacarbazole ring (also referred to as a monoazacarboline ring, and one of the carbon atoms constituting the carboline ring is a nitrogen atom) The aromatic structure such as triazole ring, pyrrole ring, pyridine ring, pyrazine ring, quinoxaline ring, thiophene ring, oxadiazole ring, dibenzofuran ring, dibenzothiophene ring, indole ring, etc. A divalent group derived from an aromatic heterocyclic ring selected from a ring group can be used.

  Furthermore, in the general formula (E), the aromatic hydrocarbon ring represented by Ar may have a substituent.

  Specific examples of the calixarene derivative used in the present invention are listed below, but the present invention is not limited to these.

  In CA-1, A represents CH or N, R represents a hydrogen atom, a methyl group, or an acetyl group, and n represents an integer of 1 to 6.

<Crown ether derivative>
The crown ether derivative used as a kind of phosphorescent dopant according to the present invention will be described.

  The crown ether derivative used in the present invention is a cyclic polyether as represented by the following general formula (B) or general formula (C), in which the entire ring becomes a polydentate ligand, and metal ions And a general term for compounds having a function of clathrating with organic ions, and some or all of them may be substituted with nitrogen or sulfur instead of oxygen atoms.

  In each of the general formula (B) and general formula (C), L represents a single bond or a divalent linking group, and Ch represents an oxygen atom or a sulfur atom. m represents an integer of 1 to 9, n represents an integer of 1 to 3, and Z represents a residue of a fluorescent compound or a residue of a phosphorescent compound.

  In each of the general formula (B) and general formula (C), the divalent linking group represented by L has the same meaning as the divalent linking group represented by A and L in the general formula (A). is there.

  In each of the general formula (B) and general formula (C), the phosphorescent compound used as the residue of the phosphorescent compound represented by Z is a phosphorescent compound (also referred to as a phosphorescent dopant) described later. And the like.

  Moreover, the crown ether derivative represented by each of the general formulas (B) and (C) may have a substituent R included in the calixarene derivative represented by the general formula (A).

  Specific examples of the crown ether derivative used in the present invention are listed below, but the present invention is not limited to these.

  In each of CE-1 and CE-2, which are the specific examples described above, A represents CH or N, and n represents an integer of 1 to 9.

  The phosphorescent compounds used in the present invention are described in, for example, Organic Letter, vol. 16, p 2579-2581 (2001), Inorganic Chemistry, Vol. 30, No. 8, 1685-1687 (1991), J. MoI. Am. Chem. Soc. , 123, 4304 (2001), Inorganic Chemistry, Vol. 40, No. 7, pages 1704-1711 (2001), Inorganic Chemistry, Vol. 41, No. 12, pages 3055-3066 (2002) , New Journal of Chemistry. 26, page 1171 (2002), and further by applying a method such as a reference described in these documents.

  In addition, for example, J. et al. Am. Chem. Soc. 123, 4304-4312 (2001), International Publication No. 00/70655 pamphlet, No. 02/15645 pamphlet, JP-A No. 2001-247859, No. 2001-345183, No. 2002-117978, 2002-170684, 2002-203678, 2002-235076, 2002-302671, 2002-324679, 2002-332291, 2002-332292, Examples include iridium complexes represented by the general formula described in JP 2002-338588 A, etc., iridium complexes exemplified as specific examples, iridium complexes represented by formula (IV) described in JP 2002-8860 A, and the like. It is done.

(Fluorescent dopant (also called fluorescent compound))
Fluorescent dopants (fluorescent compounds) include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes, perylene dyes Examples thereof include dyes, stilbene dyes, polythiophene dyes, and rare earth complex phosphors.

  As a fluorescent dopant that can be used in the present invention, the cyclodextrin derivative represented by the above general formula (D) has a fluorescent compound residue instead of the phosphorescent compound residue represented by Z. Things.

  Examples of fluorescent dopants that can be used in the present invention include phosphorescent compounds represented by Z in the crown ether derivatives represented by the general formula (B) and the general formula (C). Instead of the residue, the compound is exemplified using the residue of the fluorescent compound.

  Here, as a fluorescent compound, the specific example etc. of the pigment | dye, fluorescent compound, or fluorescent dopant as described in said fluorescent dopant (it is also mentioned fluorescent compound) are mentioned.

  Next, an injection layer, a blocking layer, an electron transport layer and the like used as the constituent layers of the organic EL element of the present invention will be described.

<< Injection layer: electron injection layer, hole injection layer >>
The injection layer is provided as necessary, and there are an electron injection layer and a hole injection layer, and as described above, it exists between the anode and the light emitting layer or the hole transport layer and between the cathode and the light emitting layer or the electron transport layer. May be.

  An injection layer is a layer provided between an electrode and an organic layer in order to reduce drive voltage and improve light emission luminance. “Organic EL element and its forefront of industrialization (issued by NTT Corporation on November 30, 1998) 2), Chapter 2, “Electrode Materials” (pages 123 to 166) in detail, and includes a hole injection layer (anode buffer layer) and an electron injection layer (cathode buffer layer).

  The details of the anode buffer layer (hole injection layer) are described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069 and the like. As a specific example, copper phthalocyanine is used. Examples thereof include a phthalocyanine buffer layer represented by an oxide, an oxide buffer layer represented by vanadium oxide, an amorphous carbon buffer layer, and a polymer buffer layer using a conductive polymer such as polyaniline (emeraldine) or polythiophene.

  The details of the cathode buffer layer (electron injection layer) are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Specifically, strontium, aluminum, etc. Metal buffer layer typified by lithium, alkali metal compound buffer layer typified by lithium fluoride, alkaline earth metal compound buffer layer typified by magnesium fluoride, oxide buffer layer typified by aluminum oxide, etc. . The buffer layer (injection layer) is preferably a very thin film, and the film thickness is preferably in the range of 0.1 nm to 5 μm although it depends on the material.

<Blocking layer: hole blocking layer, electron blocking layer>
The blocking layer is provided as necessary in addition to the basic constituent layer of the organic compound thin film as described above. For example, it is described in JP-A Nos. 11-204258, 11-204359, and “Organic EL elements and their forefront of industrialization” (issued by NTT, Inc. on November 30, 1998). There is a hole blocking (hole blocking) layer.

  The hole blocking layer has a function of an electron transport layer in a broad sense, and is made of a hole blocking material that has a function of transporting electrons and has a remarkably small ability to transport holes. The probability of recombination of electrons and holes can be improved by blocking. Moreover, the structure of the electron carrying layer mentioned later can be used as a hole-blocking layer concerning this invention as needed.

  The hole blocking layer of the organic EL device of the present invention is preferably provided adjacent to the light emitting layer.

  The hole blocking layer preferably contains the azacarbazole derivative mentioned as the host compound.

  In the present invention, when a plurality of light emitting layers having different light emission colors are provided, the light emitting layer having the shortest wavelength of light emission is preferably closest to the anode among all the light emitting layers. In this case, it is preferable to additionally provide a hole blocking layer between the shortest wave layer and the light emitting layer next to the anode next to the anode. Furthermore, it is preferable that 50% by mass or more of the compound contained in the hole blocking layer provided at the position has an ionization potential of 0.3 eV or more larger than the host compound of the shortest wave emitting layer.

  The ionization potential is defined by the energy required to emit an electron at the HOMO (highest occupied molecular orbital) level of the compound to the vacuum level, and can be obtained by the following method, for example.

  (1) Keywords using Gaussian 98 (Gaussian 98, Revision A.11.4, MJ Frisch, et al, Gaussian, Inc., Pittsburgh PA, 2002.), which is molecular orbital calculation software manufactured by Gaussian, USA. The ionization potential can be obtained as a value obtained by rounding off the second decimal place of the value (eV unit converted value) calculated by performing structural optimization using B3LYP / 6-31G *. This calculation value is effective because the correlation between the calculation value obtained by this method and the experimental value is high.

  (2) The ionization potential can also be obtained by a method of directly measuring by photoelectron spectroscopy. For example, a method known as ultraviolet photoelectron spectroscopy can be suitably used by using a low energy electron spectrometer “Model AC-1” manufactured by Riken Keiki Co., Ltd.

  On the other hand, the electron blocking layer has a function of a hole transport layer in a broad sense, and is made of a material that has a function of transporting holes and has an extremely small ability to transport electrons, and transports electrons while transporting holes. By blocking, the recombination probability of electrons and holes can be improved. Moreover, the structure of the positive hole transport layer mentioned later can be used as an electron blocking layer as needed. The film thickness of the hole blocking layer and the electron transport layer according to the present invention is preferably 3 nm to 100 nm, and more preferably 5 nm to 30 nm.

《Hole transport layer》
The hole transport layer is made of a hole transport material having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer. The hole transport layer can be provided as a single layer or a plurality of layers.

  The hole transport material has any one of hole injection or transport and electron barrier properties, and may be either organic or inorganic. For example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, Examples thereof include stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers.

  The above-mentioned materials can be used as the hole transport material, but it is preferable to use a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound.

  Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N, N ', N'-tetraphenyl-4,4'-diaminophenyl; N, N'-diphenyl-N, N'- Bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (TPD); 2,2-bis (4-di-p-tolylaminophenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ′, N′-tetra-p-tolyl-4,4′-diaminobiphenyl; 1,1-bis (4-di-p-tolyl) Aminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-p-tolylaminophenyl) phenylmethane; N, N'-diphenyl-N, N ' − (4-methoxyphenyl) -4,4'-diaminobiphenyl; N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) quadriphenyl; N, N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenylamino- (2-diphenylvinyl) benzene; 3-methoxy-4′-N, N-diphenylaminostilbenzene; N-phenylcarbazole, and also two of those described in US Pat. No. 5,061,569. Having a condensed aromatic ring in the molecule, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-3086 4,4 ', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 8 are linked in a starburst type ( MTDATA) and the like.

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used. In addition, inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material.

  JP-A-11-251067, J. Org. Huang et. al. A so-called p-type hole transport material as described in a book (Applied Physics Letters 80 (2002), p. 139) can also be used. In the present invention, these materials are preferably used because a light-emitting element with higher efficiency can be obtained.

  The hole transport layer can be formed by thinning the hole transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. it can. Although there is no restriction | limiting in particular about the film thickness of a positive hole transport layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5 nm-200 nm. The hole transport layer may have a single layer structure composed of one or more of the above materials.

  Alternatively, a hole transport layer having a high p property doped with impurities can be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, 2001-102175, J. Pat. Appl. Phys. 95, 5773 (2004), and the like.

  In the present invention, it is preferable to use a hole transport layer having such a high p property because a device with lower power consumption can be produced.

  Hereinafter, although the specific example of the compound preferably used for formation of the positive hole transport layer of the organic EL element of this invention is given, this invention is not limited to these.

  Moreover, although the reactive hole transport material shown below is also preferably used for formation of a hole transport layer, this invention is not limited to these.

《Electron transport layer》
The electron transport layer is made of a material having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. The electron transport layer can be provided as a single layer or a plurality of layers.

  Conventionally, in the case of a single electron transport layer and a plurality of layers, an electron transport material (also serving as a hole blocking material) used for an electron transport layer adjacent to the light emitting layer on the cathode side is injected from the cathode. As long as it has a function of transferring electrons to the light-emitting layer, any material can be selected and used from among conventionally known compounds. For example, nitro-substituted fluorene derivatives, diphenylquinone derivatives Thiopyrandioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives and the like. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material. Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

  Also, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) aluminum, Tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), etc., and the central metals of these metal complexes are In, Mg, Cu , Ca, Sn, Ga, or Pb can also be used as an electron transport material. In addition, metal-free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transporting material. In addition, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as an electron transport material, and an inorganic semiconductor such as n-type-Si, n-type-SiC, etc. as in the case of the hole injection layer and the hole transport layer. Can also be used as an electron transporting material.

  The electron transport layer can be formed by thinning the electron transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. Although there is no restriction | limiting in particular about the film thickness of an electron carrying layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5 nm-200 nm. The electron transport layer may have a single layer structure composed of one or more of the above materials.

  Further, an electron transport layer having a high n property doped with impurities can also be used. Examples thereof include JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, 2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.

  In the present invention, it is preferable to use an electron transport layer having such a high n property because an element with lower power consumption can be manufactured.

  Hereinafter, although the specific example of the compound preferably used for formation of the electron carrying layer of the organic EL element of this invention is given, this invention is not limited to these.

  Moreover, although the reactive electron transport material shown below is also preferably used for formation of an electron carrying layer, this invention is not limited to these.

  In addition, as the reactive electron transport material, a compound in which a reactive group that the above-described reactive host compound may have is substituted for a conventionally known electron transport material is also preferably used.

<Condensation polymer>
In the method for producing an organic EL element of the present invention, in addition to the constituent material of the organic layer of the organic EL element, the following condensation polymers can be used as appropriate.

  Hereinafter, examples of the condensation polymer used in the present invention include compounds represented by the following general formula (1), but the present invention is not limited thereto.

  In the general formula (1), [Ar] n represents an aromatic hydrocarbon ring or an aromatic heterocyclic ring having n substitutable sites. Z represents a fluorescent compound residue or a phosphorescent compound residue, and m of the n substitutable sites of Ar are linked via K. K represents a divalent linking group or a single bond. n represents a number from 1 to 3, and m represents a number from 1 to n. Here, when there are a plurality of Z and K, each may be independently the same or different. L is a divalent linking group selected from the linking group group 1 described below.

  In the general formula (1), examples of the aromatic hydrocarbon ring represented by Ar include a benzene ring, a biphenyl ring, a naphthalene ring, an azulene ring, an anthracene ring, a phenanthrene ring, a pyrene ring, a chrysene ring, a naphthacene ring, a triphenylene ring, o-terphenyl ring, m-terphenyl ring, p-terphenyl ring, acenaphthene ring, coronene ring, fluorene ring, fluoranthrene ring, naphthacene ring, pentacene ring, perylene ring, pentaphen ring, picene ring, pyrene ring, Examples include a pyranthrene ring and anthraanthrene ring. In addition, these rings may further have a substituent represented by R in the general formula (A).

  In the general formula (1), examples of the aromatic heterocycle represented by Ar include a furan ring, a thiophene ring, an oxazole ring, a pyrrole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, and a benzimidazole. Ring, oxadiazole ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indazole ring, indazole ring, benzimidazole ring, benzothiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring, cinnoline ring, quinoline ring, isoquinoline Ring, phthalazine ring, naphthyridine ring, carbazole ring, carboline ring, diazacarbazole ring (showing a ring in which one of the carbon atoms of the hydrocarbon ring constituting the carboline ring is further substituted with a nitrogen atom).

  In addition, these rings may further have a substituent which the aromatic hydrocarbon ring represented by Ar in the general formula (E) may have.

  In the general formula (1), the divalent linking group represented by K has the same meaning as the divalent linking group represented by A in the general formula (1).

  In the general formula (1), the fluorescent compound residue and phosphorescent compound residue represented by Z are the fluorescent compound residue and phosphorescent group represented by Z in the general formula (1), respectively. It is synonymous with each compound residue.

  In the general formula (1), the divalent linking group represented by L is selected from the following linking group group 1.

In the linking group group 1, R _{1 to} R ₄ each represents an alkyl group, an aromatic hydrocarbon group, or an aromatic heterocyclic group.

In the linking group group 1, examples of the alkyl group represented by R _{1 to} R ₄ include a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group, A dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, etc. are mentioned. These may further have a substituent represented by R in the general formula (A).

In the linking group group 1, examples of the aromatic hydrocarbon group represented by R _{1 to} R ₄ include a phenyl group, a p-chlorophenyl group, a mesityl group, a tolyl group, a xylyl group, a naphthyl group, an anthryl group, and an azulenyl group. Group, acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl group, biphenylyl group and the like.

  These groups may further have a substituent represented by R in the general formula (A).

In the linking group group 1, examples of the aromatic heterocyclic group represented by R _{1 to} R ₄ include a pyridyl group, a pyrimidinyl group, a furyl group, a pyrrolyl group, an imidazolyl group, a benzoimidazolyl group, a pyrazolyl group, a pyrazinyl group, Triazolyl group (for example, 1,2,4-triazol-1-yl group, 1,2,3-triazol-1-yl group, etc.), oxazolyl group, benzoxazolyl group, thiazolyl group, isoxazolyl group, isothiazolyl group , Flazanyl group, thienyl group, quinolyl group, benzofuryl group, dibenzofuryl group, benzothienyl group, dibenzothienyl group, indolyl group, carbazolyl group, carbolinyl group, diazacarbazolyl group (carbon constituting the carboline ring of the carbonyl group) One of the atoms replaced by a nitrogen atom), quinoxalinyl , Pyridazinyl group, triazinyl group, quinazolinyl group, and phthalazinyl group.

  These groups may further have a substituent which the aromatic hydrocarbon ring represented by Ar in the general formula (E) may have.

  Hereinafter, although the specific example of the condensation polymer represented by General formula (1) is shown, this invention is not limited to these.

"anode"
As the anode in the organic EL element, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (4 eV or more) is preferably used. Specific examples of such electrode substances include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ , and ZnO. Alternatively, an amorphous material such as IDIXO (In ₂ O ₃ —ZnO) capable of forming a transparent conductive film may be used. For the anode, these electrode materials may be formed into a thin film by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method, or when pattern accuracy is not required (about 100 μm or more) A pattern may be formed through a mask having a desired shape at the time of vapor deposition or sputtering of the electrode material. Or when using the substance which can be apply | coated like an organic electroconductivity compound, wet film forming methods, such as a printing system and a coating system, can also be used. When light emission is extracted from the anode, it is desirable that the transmittance be greater than 10%, and the sheet resistance as the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually in the range of 10 nm to 1000 nm, preferably in the range of 10 nm to 200 nm.

"cathode"
On the other hand, as the cathode, a material having a low work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof as an electrode material is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among these, from the point of durability against electron injection and oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than this, for example, a magnesium / silver mixture, Suitable are a magnesium / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide (Al ₂ O ₃ ) mixture, a lithium / aluminum mixture, aluminum and the like. The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The sheet resistance as a cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 nm to 200 nm. In order to transmit the emitted light, if either one of the anode or the cathode of the organic EL element is transparent or translucent, the light emission luminance is improved, which is convenient.

  Moreover, after producing the said metal by the film thickness of 1 nm-20 nm to a cathode, the transparent or semi-transparent cathode can be produced by producing the electroconductive transparent material quoted by description of the anode on it, By applying this, an element in which both the anode and the cathode are transmissive can be manufactured.

《Support substrate》
As a support substrate (hereinafter also referred to as a substrate, substrate, substrate, support, etc.) that can be used in the organic EL device of the present invention, there is no particular limitation on the type of glass, plastic, etc., and it is transparent. May be opaque. When extracting light from the support substrate side, the support substrate is preferably transparent. Examples of the transparent support substrate preferably used include glass, quartz, and a transparent resin film. A particularly preferable support substrate is a resin film capable of giving flexibility to the organic EL element.

  Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, cellulose acetate propionate (CAP), Cellulose esters such as cellulose acetate phthalate (TAC) and cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide , Polyethersulfone (PES), polyphenylene sulfide, polysulfones Cycloolefin resins such as polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic or polyarylate, Arton (trade name, manufactured by JSR) or Appel (trade name, manufactured by Mitsui Chemicals) Can be mentioned.

On the surface of the resin film, an inorganic film, an organic film, or a hybrid film of both may be formed. Water vapor permeability (25 ± 0.5 ° C.) measured by a method according to JIS K 7129-1992. , Relative humidity (90 ± 2)% RH) is preferably 0.01 g / (m ² · 24 h) or less, and further, oxygen measured by a method according to JIS K 7126-1987. A high barrier film having a permeability of 10 ⁻³ ml / (m ² · 24 hr · MPa) or less and a water vapor permeability of 10 ⁻⁵ g / (m ² · 24 h) or less is preferable.

  As a material for forming the barrier film, any material may be used as long as it has a function of suppressing entry of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like can be used. Further, in order to improve the brittleness of the film, it is more preferable to have a laminated structure of these inorganic layers and organic material layers. Although there is no restriction | limiting in particular about the lamination | stacking order of an inorganic layer and an organic layer, It is preferable to laminate | stack both alternately several times.

  The method for forming the barrier film is not particularly limited. For example, the vacuum deposition method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma weight A combination method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, and the like can be used, but an atmospheric pressure plasma polymerization method as described in JP-A-2004-68143 is particularly preferable.

  Examples of the opaque support substrate include metal plates such as aluminum and stainless steel, films, opaque resin substrates, and ceramic substrates.

  The external extraction efficiency at room temperature of light emission of the organic EL device of the present invention is preferably 1% or more, more preferably 5% or more. Here, the external extraction quantum efficiency (%) = the number of photons emitted to the outside of the organic EL element / the number of electrons sent to the organic EL element × 100.

  In addition, a hue improvement filter such as a color filter may be used in combination, or a color conversion filter that converts the emission color from the organic EL element into multiple colors using a phosphor. In the case of using a color conversion filter, the λmax of light emission of the organic EL element is preferably 480 nm or less.

<Sealing>
As a sealing means used for this invention, the method of adhere | attaching a sealing member, an electrode, and a support substrate with an adhesive agent can be mentioned, for example.

  As a sealing member, it should just be arrange | positioned so that the display area | region of an organic EL element may be covered, and concave plate shape or flat plate shape may be sufficient. Further, transparency and electrical insulation are not particularly limited.

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

In the present invention, a polymer film and a metal film can be preferably used because the element can be thinned. Furthermore, the polymer film has an oxygen permeability measured by a method according to JIS K 7126-1987 of 1 × 10 ⁻³ ml / (m ² · 24 hr · MPa) or less, and a method according to JIS K 7129-1992. It is preferable that the water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) measured in (1) is 1 × 10 ⁻³ g / (m ² · 24 h) or less. .

  For processing the sealing member into a concave shape, sandblasting, chemical etching, or the like is used.

  Specific examples of the adhesive include photocuring and thermosetting adhesives having reactive vinyl groups such as acrylic acid oligomers and methacrylic acid oligomers, and moisture curing adhesives such as 2-cyanoacrylates. be able to. Moreover, heat | fever and chemical curing types (two-component mixing), such as an epoxy type, can be mentioned. Moreover, hot-melt type polyamide, polyester, and polyolefin can be mentioned. Moreover, a cationic curing type ultraviolet curing epoxy resin adhesive can be mentioned.

  In addition, since an organic EL element may deteriorate by heat processing, what can be adhesive-hardened from room temperature to 80 degreeC is preferable. A desiccant may be dispersed in the adhesive. Application | coating of the adhesive agent to a sealing part may use commercially available dispenser, and may print like screen printing.

  In addition, it is also preferable that the electrode and the organic layer are coated on the outside of the electrode facing the support substrate with the organic layer interposed therebetween, and an inorganic or organic layer is formed in contact with the support substrate to form a sealing film. . In this case, the material for forming the film may be any material that has a function of suppressing intrusion of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like may be used. it can. Further, in order to improve the brittleness of the film, it is preferable to have a laminated structure of these inorganic layers and layers made of organic materials. The method for forming these films is not particularly limited. For example, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster-ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma A polymerization method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used.

  In the gap between the sealing member and the display area of the organic EL element, an inert gas such as nitrogen or argon, or an inert liquid such as fluorinated hydrocarbon or silicon oil can be injected in the gas phase and liquid phase. preferable. A vacuum is also possible. Moreover, a hygroscopic compound can also be enclosed inside.

  Examples of the hygroscopic compound include metal oxides (for example, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide) and sulfates (for example, sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate). Etc.), metal halides (eg calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide etc.), perchloric acids (eg perchloric acid) Barium, magnesium perchlorate, and the like), and anhydrous salts are preferably used in sulfates, metal halides, and perchloric acids.

《Protective film, protective plate》
In order to increase the mechanical strength of the element, a protective film or a protective plate may be provided on the outer side of the sealing film on the side facing the support substrate with the organic layer interposed therebetween or on the sealing film. In particular, when the sealing is performed by the sealing film, the mechanical strength is not necessarily high, and thus it is preferable to provide such a protective film and a protective plate. As a material that can be used for this, the same glass plate, polymer plate / film, metal plate / film, and the like used for the sealing can be used, but the polymer film is light and thin. Is preferably used.

《Light extraction》
The organic EL element emits light inside a layer having a refractive index higher than that of air (refractive index is about 1.7 to 2.1) and can extract only about 15% to 20% of the light generated in the light emitting layer. It is generally said. This is because light incident on the interface (interface between the transparent substrate and air) at an angle θ greater than the critical angle causes total reflection and cannot be taken out of the device, or between the transparent electrode or light emitting layer and the transparent substrate. This is because the light is totally reflected between the light and the light is guided through the transparent electrode or the light emitting layer, and as a result, the light escapes in the direction of the element side surface.

  As a method of improving the light extraction efficiency, for example, a method of forming irregularities on the surface of the transparent substrate and preventing total reflection at the transparent substrate and the air interface (US Pat. No. 4,774,435), A method of improving efficiency by providing a light collecting property to a substrate (Japanese Patent Laid-Open No. 63-314795), a method of forming a reflective surface on a side surface of an element (Japanese Patent Laid-Open No. 1-220394), and light emission from a substrate A method of forming an antireflection film by introducing a flat layer having an intermediate refractive index between the bodies (Japanese Patent Laid-Open No. 62-172691), a flat having a lower refractive index between the substrate and the light emitter than the substrate A method of introducing a layer (Japanese Patent Laid-Open No. 2001-202827), a method of forming a diffraction grating between any one of a substrate, a transparent electrode layer and a light emitting layer (including between the substrate and the outside) (Japanese Patent Laid-Open No. 11-283951) Gazette).

  In the present invention, these methods can be used in combination with the organic EL device of the present invention. However, a method of introducing a flat layer having a lower refractive index than the substrate between the substrate and the light emitter, or a substrate, transparent A method of forming a diffraction grating between any layers of the electrode layer and the light emitting layer (including between the substrate and the outside) can be suitably used.

  In the present invention, by combining these means, it is possible to obtain an element having higher luminance or durability.

  When a medium having a low refractive index is formed between the transparent electrode and the transparent substrate with a thickness longer than the wavelength of light, the light extracted from the transparent electrode has a higher extraction efficiency to the outside as the refractive index of the medium is lower.

  Examples of the low refractive index layer include aerogel, porous silica, magnesium fluoride, and a fluorine-based polymer. Since the refractive index of the transparent substrate is generally about 1.5 to 1.7, the low refractive index layer preferably has a refractive index of about 1.5 or less. Further, it is preferably 1.35 or less.

  The thickness of the low refractive index medium is preferably at least twice the wavelength in the medium. This is because the effect of the low refractive index layer is diminished when the thickness of the low refractive index medium is about the wavelength of light and the electromagnetic wave that has exuded by evanescent enters the substrate.

  The method of introducing a diffraction grating into an interface or any medium that causes total reflection is characterized by a high effect of improving light extraction efficiency. This method uses the property that the diffraction grating can change the direction of light to a specific direction different from refraction by so-called Bragg diffraction such as first-order diffraction and second-order diffraction. Light that cannot be emitted due to total internal reflection between layers is diffracted by introducing a diffraction grating in any layer or medium (in a transparent substrate or transparent electrode), and the light is removed. I want to take it out.

  The introduced diffraction grating desirably has a two-dimensional periodic refractive index. This is because light emitted from the light-emitting layer is randomly generated in all directions, so in a general one-dimensional diffraction grating having a periodic refractive index distribution only in a certain direction, only light traveling in a specific direction is diffracted. Therefore, the light extraction efficiency does not increase so much. However, by making the refractive index distribution a two-dimensional distribution, light traveling in all directions is diffracted, and light extraction efficiency is increased.

  As described above, the position where the diffraction grating is introduced may be in any of the layers or in the medium (in the transparent substrate or in the transparent electrode), but is preferably in the vicinity of the organic light emitting layer where light is generated.

  At this time, the period of the diffraction grating is preferably about 1/2 to 3 times the wavelength of light in the medium.

  The arrangement of the diffraction grating is preferably two-dimensionally repeated, such as a square lattice, a triangular lattice, or a honeycomb lattice.

<Condenser sheet>
The organic EL device of the present invention is processed on the light extraction side of the substrate so as to provide, for example, a microlens array structure, or combined with a so-called condensing sheet, for example, with respect to a specific direction, for example, the device light emitting surface. By condensing in the front direction, the luminance in a specific direction can be increased.

  As an example of the microlens array, quadrangular pyramids having a side of 30 μm and an apex angle of 90 degrees are two-dimensionally arranged on the light extraction side of the substrate. One side is preferably 10 μm to 100 μm. If it becomes smaller than this, the effect of diffraction will generate | occur | produce and color, and if too large, thickness will become thick and is not preferable.

  As the condensing sheet, for example, a sheet that is put into practical use in an LED backlight of a liquid crystal display device can be used. As such a sheet, for example, a brightness enhancement film (BEF) manufactured by Sumitomo 3M Limited can be used. As the shape of the prism sheet, for example, the base material may be formed by forming a △ -shaped stripe having a vertex angle of 90 degrees and a pitch of 50 μm, or the vertex angle is rounded and the pitch is changed randomly. Other shapes may be used.

  Moreover, in order to control the light emission angle from a light emitting element, you may use together a light diffusing plate and a film with a condensing sheet. For example, a diffusion film (light-up) manufactured by Kimoto Co., Ltd. can be used.

<< Applications of organic EL elements >>
The organic EL element of the present invention can be used as a display device, a display, and various light emission sources. For example, lighting devices (home lighting, interior lighting), clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources of optical storage media, light sources of electrophotographic copying machines, light sources of optical communication processors, light Although the light source of a sensor etc. are mentioned, It is not limited to this, Especially, it can use effectively for the use as a backlight of a liquid crystal display device, and a light source for illumination.

  In the organic EL device of the present invention, patterning may be performed by a metal mask, an ink jet printing method, or the like at the time of film formation, if necessary. In the case of patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or the entire layer of the element may be patterned. In the fabrication of the element, a conventionally known method is used. Can do.

  The light emission color of the organic EL device of the present invention and the compound according to the present invention is shown in FIG. 4.16 on page 108 of “New Color Science Handbook” (edited by the Japan Color Society, University of Tokyo Press, 1985). It is determined by the color when the result measured with the total CS-1000 (manufactured by Konica Minolta Sensing) is applied to the CIE chromaticity coordinates.

Further, when the organic EL element of the present invention is a white element, white means that the chromaticity in the CIE1931 color system at 1000 Cd / m ² is X when the 2-degree viewing angle front luminance is measured by the above method. = 0.33 ± 0.07 and Y = 0.33 ± 0.1.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these.

  The structures of the compounds used in the examples are shown below.

Example 1
<< Preparation of Organic Electroluminescence Element 1-1 (1) >>: Vapor Deposition + Lamination As shown below, anode-side substrate 1-1-A and cathode-side substrate 1-1-B were respectively prepared, and then the anode The organic electroluminescent element 1-1 (1) was produced by bonding the side substrate 1-1-A and the cathode side substrate 1-1-B.

<< Preparation of Anode Side Substrate 1-1-A >>
This ITO transparent electrode was provided after patterning a substrate (NH Techno Glass, NA45) in which ITO (indium tin oxide) was deposited to a thickness of 100 nm on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode. The transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  On this transparent support substrate, a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water at 3000 rpm for 30 seconds. Then, the film was formed by spin coating and then dried at 200 ° C. for 1 hour to provide a first hole transport layer having a thickness of 30 nm.

  The transparent support substrate provided with the first hole transport layer is fixed to a substrate holder of a commercially available vacuum deposition apparatus. On the other hand, as a material for forming the second hole transport layer on a resistance heating boat made of molybdenum, 4, 4′- 200 mg of bis [N- (1-naphthyl) -N-phenylamino] biphenyl (OC-2: α-NPD) is added, and 4,4-di (n-carbazole) is used as a host compound in another molybdenum resistance heating boat. 200 mg of biphenyl (OC-6) was put, 50 mg of tris (2-phenylpyridine) iridium (PD-1) was put in another resistance heating boat made of molybdenum, and attached to a vacuum deposition apparatus.

Next, after reducing the pressure of the vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat containing OC-2 was heated by heating, and deposited on the first hole transport layer at a deposition rate of 0.1 nm / second. Thus, a second hole transport layer having a thickness of 30 nm was provided.

  Further, the heating boat containing OC-6 and PD-1 was energized and heated, and co-deposited on the hole transport layer at a deposition rate of 0.2 nm / second and 0.012 nm / second, respectively. A 25 nm light emitting layer was provided, and an anode side substrate 1-1-A was produced. In addition, the substrate temperature at the time of vapor deposition was room temperature.

<< Preparation of Cathode Side Substrate 1-1-B >>
A 100 mm × 100 mm × 1.1 mm glass substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes. This was fixed to a substrate holder of a commercially available vacuum deposition apparatus. 200 mg of bis (2-methyl-8-quinolinolato)-(p-phenylphenolate) aluminum (OC-28) as a material for forming an electron transport layer is placed in a resistance heating boat made of molybdenum. As a host compound, 200 mg of OC-6 was put, 50 mg of PD-1 was put in another resistance heating boat made of molybdenum, attached to a vacuum deposition apparatus, and the vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa.

  After depositing 110 nm of aluminum and then 0.5 nm of lithium fluoride on the substrate to form a cathode, the heating boat containing OC-28 was energized and heated, and deposited at a deposition rate of 0.1 nm / second. Thus, an electron transport layer having a thickness of 50 nm was provided.

  Further, the heating boat containing OC-6 and PD-1 was energized and heated, and co-deposited on the electron transport layer at a deposition rate of 0.2 nm / second and 0.012 nm / second, respectively, to a film thickness of 25 nm. The cathode layer substrate 1-1-B was prepared. In addition, the substrate temperature at the time of vapor deposition was room temperature.

<< Production of Organic EL Element 1-1 (1) by Bonding >>
The obtained glove box in a nitrogen atmosphere without contacting the anode-side substrate 1-1-A and the cathode-side substrate 1-1-B with the atmosphere (under an atmosphere of high purity nitrogen gas having a purity of 99.999% or more) ) 1-1-A and 1-1-B are superposed and pressure-bonded under a pressure of 0.1 MPa in a reduced pressure environment of 1 × 10 ⁻² Pa, and adhered and fixed to produce an organic EL element 1-1. did.

<< Production of Organic EL Elements 1-1 (2) to (5) >>
Organic EL elements 1-1 (2) to 1-1 (5) were respectively manufactured in the same manner except that production batches were different in the production of the organic EL element 1-1 (1).

<< Production of Organic EL Elements 1-2 to 1-14 >>
In the production of the organic EL element 1-1, except that the film thickness of each light emitting layer of the anode side substrate 1-1-A and the cathode side substrate 1-1-B was changed to the film thickness shown in Table 1. Elements 1-2 to 1-14 were fabricated in the same manner.

  In Table 1, organic EL elements 1-2 (1) to 1-2 (5), 1-5 (1) and 1-5 (2), 1-6 (1), 1-6 (2) , 1-7 (1), 1-7 (2) represent different samples of each batch.

<< Evaluation of Organic EL Elements 1-1 to 1-14 >>
For each of the obtained organic EL elements 1-1 to 1-14, color unevenness and driving voltage (also simply referred to as voltage) were measured and evaluated by the methods described below.

  Moreover, when evaluating the obtained organic EL elements 1-1 to 1-14, the non-light-emitting surface of each organic EL element after production was covered with a glass case, and a glass substrate having a thickness of 300 μm was used as a sealing substrate. Then, an epoxy-based photo-curing adhesive (Lux Track LC0629B manufactured by Toagosei Co., Ltd.) is applied as a sealant around the periphery, and this is placed on the cathode so as to be in close contact with the transparent support substrate. , Cured and sealed to form an illumination device as shown in FIGS. 3 and 4 for evaluation.

  FIG. 3 is a schematic view of the lighting device, and the organic EL element 101 is covered with a glass cover 102. The sealing operation with the glass cover was a glove box in a nitrogen atmosphere without bringing the organic EL element 101 into contact with the atmosphere (performed in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more). 4 shows a cross-sectional view of the lighting device. In FIG. 4, reference numeral 105 denotes a cathode, 106 denotes an organic EL layer, and 107 denotes a glass substrate with a transparent electrode. The glass cover 102 is filled with nitrogen gas 108 and a water catching agent 109 is provided.

<Measurement of drive voltage>
The voltage at the start of light emission was measured at a temperature of 23 ° C. and in a dry nitrogen gas atmosphere. Note that the voltage at the start of light emission was measured when the luminance was 50 cd / m ² or more. A spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing) was used for the measurement of luminance.

<Measurement of non-light emission point and color unevenness>
About the produced organic EL element, the non-light-emission point and color nonuniformity of the light emission surface when the brightness | luminance was set to 300 cd / m < ² > or more were measured by visual observation in 23 degreeC and dry nitrogen gas atmosphere.

  The obtained results are shown in Table 1.

  Moreover, about the evaluation, the following rank evaluation was performed.

○: No non-light emitting point and color unevenness were observed,
X: Non-light emitting point and color unevenness were observed,
The drive voltage is expressed as a relative value when the value of the organic EL element 1-1 is 100.

  From Table 1, it can be seen that the organic EL element of the present invention exhibits good characteristics for both the non-light emitting point and the color unevenness. Further, when the thickness of the light emitting layer is 40 nm or less, non-light emitting points and light emission unevenness occur, and when the thickness of the light emitting layer exceeds 100 nm, the light emission starting voltage is increased and sufficient performance as an organic EL element is exhibited. Obviously you can't.

Example 2
<< Preparation of the organic EL element 2-1 >>: Preparation by coating and bonding As shown below, the anode side substrate 2-1-A and the cathode side substrate 2-1-B were respectively prepared, and then the anode side substrate. The organic electroluminescent element 2-1 was produced by bonding 2-1-A and this cathode side board | substrate 2-1-B.

<< Fabrication of anode side substrate 2-1-A >>
A transparent substrate provided with this ITO transparent electrode after patterning a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) on which a 100 nm ITO (indium tin oxide) film is formed on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode The support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and UV ozone cleaned for 5 minutes.

  A solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water on this transparent support substrate at 3000 rpm for 30 seconds. After film formation by a spin coating method, the film was dried at 200 ° C. for 1 hour to provide a first hole transport layer having a thickness of 30 nm.

  A solution obtained by dissolving 30 mg of MO-10 in 3 ml of toluene was formed on the first hole transport layer by spin coating at 1000 rpm for 30 seconds, and heated at 150 ° C. for 1 hour under nitrogen. The insolubilization treatment was carried out by polymerizing reactive groups in the MO-10 molecule.

  As a result, a 30-nm-thick second hole transport layer made of a polymer film of MO-10 was provided by heat treatment. Further, a solution obtained by dissolving 30 mg of OC-6 and 1.5 mg of PD-1 in 3 ml of toluene was formed on the second hole transporting layer by spin coating under conditions of 1500 rpm and 30 seconds. The substrate was dried at 0 ° C. for 1 hour, a light emitting layer having a thickness of 25 nm was provided, and an anode side substrate 2-1-A was produced.

<< Production of Cathode Side Substrate 2-1-B >>
A 100 mm × 100 mm × 1.1 mm glass substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes. This was fixed to a substrate holder of a commercially available vacuum deposition apparatus. The vacuum chamber was attached to a vacuum deposition apparatus, and the vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa. An aluminum-magnesium alloy 110 nm was vapor-deposited on the substrate to form a cathode.

  Separately, a solution prepared by radical polymerization of MO-52 using benzoyl peroxide as an initiator and dissolving 30 mg of MO-52 polymer (number average molecular weight 71,000) in 3 ml of dichlorobenzene was placed on the cathode at 1000 rpm. The film was formed by spin coating under conditions of 30 seconds and dried at 150 ° C. for 1 hour to provide an electron transport layer having a thickness of 50 nm.

  Further, a solution obtained by dissolving 30 mg of OC-6 and 1.5 mg of PD-1 in 3 ml of toluene was formed on the electron transport layer by spin coating at 1500 rpm for 30 seconds, and the temperature was increased to 150 ° C. The substrate was dried for 1 hour, a light emitting layer having a thickness of 25 nm was provided, and a cathode side substrate 2-1-B was manufactured. In addition, the substrate temperature at the time of vapor deposition was room temperature.

<< Production of Organic EL Element 2-1 by Bonding >>
Similarly to the production of the organic EL element 1-1 of Example 1, the anode side substrate 1-1-A and the cathode side substrate 1-1-B were bonded to produce an organic EL element 2-1. .

<< Production of Organic EL Element 2-2 >>: Comparative Example (Production by Sequential Deposition Lamination)
A transparent substrate provided with this ITO transparent electrode after patterning a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) on which a 100 nm ITO (indium tin oxide) film is formed on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode The support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and UV ozone cleaned for 5 minutes.

  A solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water on this transparent support substrate at 3000 rpm for 30 seconds. After film formation by a spin coating method, the film was dried at 200 ° C. for 1 hour to provide a first hole transport layer having a thickness of 30 nm.

  The transparent support substrate provided with the first hole transport layer is fixed to a substrate holder of a commercially available vacuum vapor deposition apparatus. On the other hand, 200 mg of OC-1 is used as a material for forming a second hole transport layer in a resistance heating boat made of molybdenum. In another molybdenum resistance heating boat, 200 mg of OC-6 as a host compound, 50 mg of PD-1 and 200 mg of OC-18 were put in another molybdenum resistance heating boat and attached to a vacuum deposition apparatus.

Next, after reducing the pressure of the vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat containing OC-1 was energized and heated, and deposited on the first hole transport layer at a deposition rate of 0.1 nm / second. Thus, a second hole transport layer having a thickness of 30 nm was provided.

  Further, the heating boat containing OC-6 and PD-1 was energized and heated, and co-deposited on the second hole transport layer at a deposition rate of 0.2 nm / second and 0.012 nm / second, respectively. A light emitting layer having a thickness of 50 nm is provided, and then the heating boat containing OC-18 is energized and heated, and vapor deposition is performed on the light emitting layer at a deposition rate of 0.1 nm / sec. A layer was provided. Finally, 0.5 nm of lithium fluoride and then 110 nm of aluminum were vapor-deposited to form a cathode, and an organic EL element 2-2 was produced.

<< Evaluation of Organic EL Element 1-1 (1) 2, 2-1, 2-2 >>
For each of the obtained organic EL devices 1-1 (1), 2-1, and 2-2, the external extraction quantum efficiency, the light emission lifetime, and the driving voltage (also simply referred to as voltage) are not emitted by the methods described below. Spots and color unevenness were measured and evaluated. The measurement of driving voltage, non-light emitting point, and color unevenness was performed in the same manner as in Example 1.

  The external extraction quantum efficiency, light emission lifetime, and driving voltage are expressed as relative values when the organic EL element 1-1 (1) is 100.

<Measurement of external extraction quantum efficiency>
About the produced organic EL element, the external extraction quantum efficiency (%) when a ^2.5 mA / cm ² constant current was applied in a dry nitrogen gas atmosphere at 23 ° C. was measured. For the measurement, a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing) was used.

<Measurement of luminous lifetime>
When driving at a constant current of ^2.5 mA / cm ^{2 at} a temperature of 23 ° C. and a dry nitrogen gas atmosphere, the time required for the luminance to drop to half of the luminance immediately after the start of light emission (initial luminance) was measured, This was used as a lifetime index as a half-life time (τ 0.5). For the measurement, a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing) was used in the same manner.

  Measurement results of the external extraction quantum efficiency, light emission lifetime, drive voltage, non-light emission point, and color unevenness of the organic EL elements 1-1 (present invention), 2-2 (present invention), and 2-3 (comparative example) It is shown in 2. In addition, each measured value was represented with the relative value when the organic EL element 1-5 is set to 100.

  From Table 2, the basic performance of the organic EL element such as external extraction quantum efficiency, light emission lifetime, drive voltage, non-light emission point, and color unevenness shows the same performance as when using the conventional vapor deposition lamination process. . In particular, even when a coating method that has been said to be inferior to the vapor deposition system so far was used, almost the same performance was exhibited. It has been found that by using the manufacturing method of the present invention, an innovative organic EL element manufacturing process can be provided without degrading various performances as an organic EL element.

Example 3
<Production of full-color display device>
(Blue light emitting organic EL device)
In the production of the organic EL element 2-1 of Example 2, a blue light-emitting organic EL element 2-1B (blue) was produced in the same manner except that PD-1 was changed to PD-12.

(Green light-emitting organic EL device)
The organic EL element 2-1 produced in Example 2 was used as the green light-emitting organic EL element.

(Red light emitting organic EL device)
A red light-emitting organic EL element 2-1R (red) was produced in the same manner as in the organic EL element 2-1 of Example 2, except that PD-1 was changed to PD-6.

  The red, green and blue light-emitting organic EL elements are juxtaposed on the same substrate to produce an active matrix type full-color display device having the form shown in FIG. 1, and FIG. 2 shows the display of the produced display device. Only the schematic diagram of part A is shown. That is, a wiring portion including a plurality of scanning lines 5 and data lines 6 on the same substrate, and a plurality of juxtaposed pixels 3 (light emission color is a red region pixel, a green region pixel, a blue region pixel, etc.) The scanning lines 5 and the plurality of data lines 6 in the wiring portion are each made of a conductive material, and the scanning lines 5 and the data lines 6 are orthogonal to each other in a lattice shape and are connected to the pixels 3 at the orthogonal positions ( Details are not shown). The plurality of pixels 3 are driven by an active matrix system provided with an organic EL element corresponding to each emission color, a switching transistor as an active element, and a driving transistor, and a scanning signal is applied from a scanning line 5. Then, an image data signal is received from the data line 6 and light is emitted according to the received image data. In this way, a full color display device was produced by appropriately juxtaposing the red, green, and blue pixels.

  It was confirmed that by driving the full-color display device, a full-color moving image display having a high light emission efficiency and a long light emission lifetime was obtained.

Example 4
<Production of white lighting device>
(A) In the organic EL element 2-1 of Example 3, PD-1 used for the anode side substrate 2-1-A and the cathode side substrate 2-1-B is PD-1, PD-6, PD-12. A white light-emitting organic EL device 2-1W (white) was produced in the same manner except that it was changed to.

  (B) In the organic EL element 2-1 of Example 3, PD-1 used for the anode side substrate 2-1-A was PD-13, and PD used for the production of the cathode side substrate 2-1-B was further used. A white light-emitting organic EL device 3-1W (white) was produced in the same manner except that -1 was changed to PD-10.

  When evaluating the obtained organic EL elements 2-1W and 3-1W, the non-light emitting surface was covered with a glass case in the same manner as in Example 1 to obtain a lighting device. The illuminating device could be used as a thin illuminating device that emits white light with high luminous efficiency and long emission life.

It is the schematic diagram which showed an example of the display apparatus comprised from an organic EL element. It is a schematic diagram of a display part. It is the schematic of an illuminating device. It is sectional drawing of an illuminating device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Display 3 Pixel 5 Scan line 6 Data line 7 Power supply line 10 Organic EL element 11 Switching transistor 12 Drive transistor 13 Capacitor A Display part B Control part 107 Glass substrate with a transparent electrode 106 Organic EL layer 105 Cathode 102 Glass cover 108 Nitrogen gas 109 Water catcher

Claims (9)

In a method for producing an organic electroluminescence device having at least an anode and a cathode on a support substrate, and having an organic layer including at least one light emitting layer between the anode and the cathode,
The total film thickness T (EM) (nm) of the light emitting layer satisfies the following relational expression (1), at least one of the light emitting layers has a phosphorescent material, and at least one of the organic layers is: The manufacturing method of the organic electroluminescent element characterized by having the process formed by bonding of the layer A and the layer B.
Relational expression (1)
40 nm <T (EM) ≦ 100 nm The method for producing an organic electroluminescent element according to claim 1, wherein the organic layer has three or more layers. The method for producing an organic electroluminescent element according to claim 1, wherein the layer A and the layer B each contain a compound having the same structure as a main component. Either of the said layer A or the said layer B contains a phosphorescence-emitting material, The manufacturing method of the organic electroluminescent element of any one of Claims 1-3 characterized by the above-mentioned. The said layer A and the said layer B each contain a phosphorescence-emitting material, The manufacturing method of the organic electroluminescent element of any one of Claims 1-3 characterized by the above-mentioned. The method for producing an organic electroluminescent element according to any one of claims 1 to 5, wherein the phosphorescent material is an iridium complex or a platinum complex. An organic electroluminescence element produced by the method for producing an organic electroluminescence element according to claim 1. An illuminating device comprising the organic electroluminescence element according to claim 7. A display device comprising the organic electroluminescence element according to claim 7.

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