JP2014103290A - Organic electroluminescent element, method for manufacturing organic electroluminescent element, and metal oxide particle-containing composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic electroluminescent element high in light-emitting luminance, low in driving voltage, long in light-emitting life, and uniform in light emission, and to provide a flexible organic electroluminescent element, a method for inexpensively manufacturing the organic electroluminescent element, and a metal oxide particle-containing composition for manufacturing the organic electroluminescent element.SOLUTION: An organic electroluminescent element of the present invention is an organic electroluminescent element having at least one functional layers A and a light emitting layer between a positive electrode and a negative electrode. The functional layers A contain self-dispersing metal oxide particles.

Description

  The present invention relates to an organic electroluminescence device, a method for producing an organic electroluminescence device, and a composition containing metal oxide particles, and in particular, a flexible organic electroluminescence device having a low driving voltage, a long emission lifetime, and a method for producing the same. The present invention relates to a composition containing metal oxide particles for production.

  An organic electroluminescence element (hereinafter also referred to as an organic EL element) has a configuration in which a light emitting layer containing a light emitting compound is sandwiched between a cathode and an anode, and holes injected from the anode by applying an electric field. This is a light emitting device that utilizes the emission of light (fluorescence / phosphorescence) when electrons injected from the cathode recombine in the light emitting layer to generate excitons and the excitons are deactivated. . An organic EL element is an all-solid-state element composed of an organic material film having a thickness of only a submicron between electrodes, and can emit light at a voltage of several volts to several tens of volts. Therefore, it is expected to be used for next-generation flat display and lighting.

  The element structure of the organic EL element is composed of at least a cathode / organic layer / anode. This organic layer had a two-layer structure consisting of a light emitting layer / hole injection layer in the early organic EL elements, but now, in order to obtain high luminous efficiency and a long driving life, an electron injection layer / electron layer is used. Various multilayer structures such as a five-layer structure including a transport layer / a light emitting layer / a hole transport layer / a hole injection layer have been proposed. These layers other than the light emitting layer such as the electron injection layer, the electron transport layer, the hole transport layer, and the hole injection layer have the effect of facilitating the injection and transport of charges to the light emitting layer, or block the electron current and positive by blocking. It is said that there are effects such as maintaining the balance of the hole current and suppressing diffusion of light energy excitons.

  Attempts have been made so far to mix an acidic substance with a hole injection material and a transport material for the purpose of improving charge transport capability and charge injection capability.

  In Patent Document 1, an oxidizing substance is used as a dopant for the purpose of lowering the voltage, increasing the brightness, extending the lifetime, and eliminating defects, and the oxidizing substance includes a metal halide, Lewis acid, organic acid, arylamine. And acidic substances such as salts with metal halides or Lewis acids.

  For the purpose of extending the life by improving the charge transport ability and the charge injection ability, an attempt has been made to increase the electrical conductivity by mixing the acidic substance with the hole transport material in the hole injection layer. Yes. However, when an acidic substance such as that disclosed in Patent Document 1 is used for the hole injection layer, this acidic substance reacts with the anode, causing a problem of deterioration in device performance. Therefore, the life extension according to Patent Document 1 is insufficient, and the life needs to be further improved.

  In Patent Document 2, a thin film is formed by a vapor deposition method using a metal oxide such as vanadium pentoxide or molybdenum trioxide for the purpose of obtaining a hole injection layer having good injection characteristics and charge transfer characteristics. . However, since the manufacturing method disclosed in Patent Document 2 uses a vacuum deposition method, the production speed is low and the production cost cannot be suppressed.

  An example in which an organic EL element containing a metal oxide is manufactured by a coating method capable of mass production is disclosed in Patent Document 3. Patent Document 3 describes that a charge injection layer was produced by a screen printing method using a slurry in which molybdenum oxide particles having an average particle diameter of 20 nm produced by pulverization were dispersed in a solvent. However, in the method of pulverizing molybdenum oxide as in Patent Document 3, particles having a particle diameter of 50 nm or more are included. For example, if the thickness of the hole injection layer is about 20 nm, Large diameter particles penetrate through the hole injection layer, which causes uneven brightness. Further, it is difficult to stably disperse molybdenum oxide particles produced by pulverization in a solution without agglomeration, and aggregation also causes generation of coarse particles.

  Patent Document 4 discloses a method for stably dispersing metal oxide particles in a solution without agglomeration. In this known example, there is a description that the dispersibility of the dispersion of metal oxide particles is improved by attaching a protective agent to the metal oxide particles. However, in this invention, the protective agent having a function as a dispersant remains in the organic thin film, and the driving voltage and the light emission lifetime are insufficient. In addition, high temperature heating is required to evaporate and decompose the protective agent. Therefore, there is a problem that it is not suitable for a flexible organic EL element using a resin as a base material.

  Further, when a layer of metal oxide particles is applied using a base material that can be heated at high temperature and a dispersion of metal oxide particles containing a dispersant is used, even if heating is performed, the dispersant is slightly Will remain. The problem that the device performance deteriorates due to diffusion of the dispersant remaining in the film into the light emitting layer or the like in the organic thin film has been clarified.

Japanese Patent No. 3748491 JP 2006-155978 A JP 2008-041894 A JP 2011-233941 A

  The present invention has been made in view of the above-mentioned problems and situations, and the problem to be solved is to provide an organic electroluminescence device having high emission luminance, low driving voltage, long emission lifetime, and uniform emission. is there. Moreover, it is providing a flexible organic electroluminescent element. Furthermore, it is providing the manufacturing method of the said organic electroluminescent element of low cost, and the metal oxide particle containing composition for manufacturing the said organic electroluminescent element.

  In order to solve the above problems, the present inventor has a good dispersibility in the coating liquid even when the self-dispersing metal oxide particles are not coated with a dispersant in the process of examining the cause of the above problems, etc. The present inventors have found that a uniform functional layer can be formed and that adverse effects on the driving voltage and the light emission lifetime due to the dispersant can be avoided.

  That is, the said subject which concerns on this invention is solved by the following means.

  1. An organic electroluminescence device having at least one functional layer A and a light emitting layer between an anode and a cathode, wherein the functional layer A contains self-dispersing metal oxide particles. Luminescence element.

  2. The organic electroluminescence device according to item 1, wherein at least one of the metal elements constituting the metal oxide particles is a metal element selected from Group 1 to Group 13 of the Periodic Table.

  3. 3. The organic electroluminescence element according to item 2, wherein the metal element is molybdenum or tungsten.

  4). The number average particle diameter of the metal oxide particles is in the range of 5 to 100 nm. The organic electroluminescent element according to any one of items 1 to 3, wherein

  5. The number average particle diameter of the metal oxide particles is in the range of 5 to 20 nm. The organic electroluminescence element according to any one of items 1 to 3, wherein

  6). The organic electroluminescent element according to any one of claims 1 to 5, wherein the functional layer A is provided between the anode and the light emitting layer.

  7). 6. The organic electroluminescence device according to any one of items 1 to 5, wherein a hole transport layer is provided between the functional layer A and the light emitting layer.

  8). 6. The organic electroluminescence element according to any one of items 1 to 5, wherein a hole injection layer is provided between the functional layer A and the light emitting layer.

  9. The organic electroluminescence device according to item 8, wherein the hole injection layer contains an acidic substance as a dopant.

  10. 9. The organic electroluminescence device according to item 8, wherein the hole injection layer contains a polythiophene derivative and contains an acidic substance as a dopant.

  11. It is a metal oxide particle containing composition which forms the said functional layer A which the organic electroluminescent element as described in any one of 1st term | claim to 10th term | claim, Comprising: Self-dispersible metal oxide particle | grains are the following. A metal oxide particle-containing composition dispersed in a medium containing a solvent.

  12 It is a manufacturing method of the organic electroluminescent element which manufactures the organic electroluminescent element as described in any one of 1st term | claim to 10th term | term, Comprising: The said functional layer A is formed with a wet process, The organic characterized by the above-mentioned Manufacturing method of electroluminescent element.

  By the above means of the present invention, it is possible to provide an organic electroluminescence device having high emission luminance, low driving voltage, long emission lifetime, and uniform emission. In addition, a flexible organic electroluminescence element can be provided. Furthermore, the manufacturing method of the said organic electroluminescent element of low cost and the metal oxide particle containing composition for manufacturing the said organic electroluminescent element can be provided.

  The expression mechanism or action mechanism of the effect of the present invention is not clear, but is presumed as follows.

  The metal oxide particles promote the transfer of holes moving from the anode, and have the effect of lowering the driving voltage and improving the emission lifetime. The metal oxide particles are generally produced by pulverizing large metal oxide particles, but the metal oxide particles are poorly dispersible and tend to aggregate to form coarse particles. Coarse particles protrude from the functional layer formed by the composition containing the metal oxide particles, affect the movement of holes or electrons in other layers, and light emission becomes nonuniform.

  In order to improve this, the metal oxide particles can be coated with a dispersant to prevent the generation of coarse particles. However, the dispersant diffuses into an organic layer such as a light-emitting layer and moves electrons and holes. Inhibiting or hindering the movement of holes between metal oxide particles, the dispersing agent cannot exert a sufficient effect for lowering the driving voltage and improving the life.

  Since the self-dispersing metal oxide particles according to the present invention hardly aggregate in the metal oxide particle-containing composition even if they are not coated with a dispersant, a functional layer having a uniform thickness is formed. In addition, when the surface of the self-dispersing oxide particles has a compact polar group such as an OH group, the volume of the polar group forming the charge double layer is the volume of the dispersant when coated with the dispersant. Since it is very small in comparison, hole movement between metal oxide particles is easy, and no adverse effect is caused.

  Further, when the hole injection layer contains an acidic substance, a functional layer containing metal oxide particles between the anode and the hole injection transport layer having an acidic substance (this also has the function of a hole injection layer). ), The reaction between the acidic substance and the anode can be reduced, and further improvement in device performance can be achieved.

Schematic sectional view showing an example of the configuration of the organic EL element of the present invention

  The organic electroluminescent device of the present invention is an organic electroluminescent device having at least one functional layer A between an anode and a cathode, and the functional layer A contains self-dispersing metal oxide particles. It is characterized by. This feature is a technical feature common to the inventions according to claims 1 to 12.

  As an embodiment of the present invention, from the viewpoint of manifesting the effect of the present invention, the metal element constituting the metal oxide particles is at least one selected from Group 1 to Group 13 elements of the Periodic Table Preferably, the metal element is molybdenum or tungsten.

  Moreover, it is preferable that the number average particle diameter of the metal oxide particles is in the range of 5 to 100 nm because an effect of reducing luminance unevenness is obtained, and it is further light emission in the range of 5 to 20 nm. Is preferable because an effect of uniforming is obtained.

  Furthermore, in this invention, it is preferable to have the said functional layer A between an anode and a light emitting layer, and it is more preferable to have a positive hole transport layer between the said functional layer A and the said light emitting layer. Thereby, the effect which improves luminous efficiency is acquired. In addition, by having a hole injection layer between the functional layer A and the light emitting layer, an effect of improving the light emission lifetime is obtained, and particularly when the hole injection layer is doped with an acidic substance. In addition, a great effect is obtained, and further, since the hole injection layer contains a polythiophene derivative, the emission lifetime is improved and high luminous efficiency is obtained.

  From the viewpoint of mass production, it is preferable that the organic electroluminescence device for producing the organic electroluminescence device of the present invention is a production method of an embodiment in which the functional layer A is formed by a wet process.

  Moreover, the metal oxide particle containing composition used with the manufacturing method of the organic electroluminescent element of this invention has high dispersion stability, and is suitable for mass production.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, in this application, "-" is used in the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

<< Structure of organic electroluminescence element >>
The organic EL device of the present invention has at least one functional layer A between the anode and the cathode, and the functional layer A contains self-dispersing metal oxide particles.

  The functional layer is a layer between the anode and the cathode, which contributes to the performance of the organic EL element. The functional layer may be a layer made of an inorganic compound or an organic compound. A layer containing both of these may also be used.

  A preferred example of the organic EL device of the present invention is shown in FIG. As shown in FIG. 1, an organic electroluminescence device 100 according to a preferred embodiment of the present invention has a flexible support substrate 1. An anode 2 is formed on the flexible support substrate 1, a functional layer 20 is formed on the anode 2, and a cathode 8 is formed on the functional layer 20.

  The functional layer 20 refers to each layer constituting the organic EL element 100 provided between the anode 2 and the cathode 8.

  The functional layer 20 includes, for example, a hole injection layer 3, a hole transport layer 4, a light emitting layer 5, an electron transport layer 6, and an electron injection layer 7 as individual functional layers. A block layer, an electronic block layer, etc. may be included.

  The anode 2, the functional layer 20, and the cathode 8 on the flexible support substrate 1 are sealed with a flexible sealing member 10 through a sealing adhesive 9. Here, the hole injection layer 3 or the hole transport layer 4 may contain the self-dispersing metal oxide particles according to the present invention to become the functional layer A, or the functional layer A and the light emitting layer. The hole injection layer 3 or the hole transport layer 4 may be provided between the layers.

  In addition, these layer structures (refer FIG. 1) of the organic EL element 100 show the preferable specific example, and this invention is not limited to these.

  For example, the organic EL device according to the present invention may have the layer structures (i) to (viii).

(I) Flexible support substrate / anode / functional layer A / light emitting layer / electron transport layer / cathode / thermal conductive layer / sealing adhesive / sealing member (ii) flexible support substrate / anode / functional layer A / hole transport layer / light emitting layer / electron transport layer / cathode / thermal conductive layer / sealing adhesive / sealing member (iii) flexible support substrate / anode / functional layer A / hole transport layer / light emission Layer / hole blocking layer / electron transport layer / cathode / thermal conductive layer / sealing adhesive / sealing member (iv) flexible support substrate / anode / functional layer A / hole transport layer / light emitting layer / positive Hole block layer / electron transport layer / cathode buffer layer / cathode / thermal conductive layer / sealing adhesive / sealing member (v) flexible support substrate / anode / anode buffer layer / functional layer A / hole transport layer / Light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode / thermal conductive layer / sealing adhesive / sealing member (vi) glass support / anode / hole injection / Functional layer A / light emitting layer / electron injection layer / cathode / sealing member (vii) glass support / anode / functional layer A / hole injection layer / hole transport layer / light emitting layer / electron injection layer / cathode / sealing Stopping member (viii) Glass support / anode / functional layer A / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode / sealing member << functional layer A >>
The functional layer A according to the present invention may be a layer formed by adding self-dispersing metal oxide particles to a known hole injection layer, hole transport layer, electron transport layer or electron injection layer. Alternatively, it may be a layer formed only of self-dispersing metal oxide particles.

  The functional layer A is preferably provided between the anode and the light-emitting layer in order to facilitate the movement of holes, and more preferably provided between the anode and the hole transport layer. And a hole injection layer.

  When the functional layer A is provided between the anode and the light emitting layer, or when a hole transport layer is provided between the functional layer A and the light emitting layer, the functional layer A is a hole injection layer. Function as. Here, when the functional layer A is formed by adding self-dispersing metal oxide particles to a known hole injection material, even if the hole injection material exists between the metal oxide particles, Since the hole transfer of the hole injection material is easy, the effect of the metal oxide particles is sufficiently exhibited.

  More preferably, a hole injection layer is provided between the functional layer A and the light emitting layer. In this case, the functional layer A is preferably formed of only self-dispersing metal oxide particles. In particular, when the hole injection layer is doped with an acidic substance, the functional layer A prevents the acidic substance from moving to the anode, so that the anode is prevented from being deteriorated and the light emission life is improved. In addition, when the hole injection layer is formed by doping polythiophene with an acidic substance, a compound exhibiting strong acidity such as PSS is used as the acidic substance.

  The layer thickness of the functional layer A is preferably in the range of 5 to 40 nm. If it is 5 nm or more, the emission lifetime is excellent, and if it is 40 nm or less, the emission efficiency is excellent. Furthermore, it is more preferable if the layer thickness of the functional layer A is in the range of 5 to 30 nm.

《Metal oxide particles》
The functional layer A according to the present invention has self-dispersing metal oxide particles.

  In the present invention, the self-dispersibility means that the metal oxide particles can be dispersed in ethanol at a concentration of 0.6% by mass without using a dispersant or without covering the surface of the metal oxide particles with an organic compound. The property refers to a property, and specifically, a property in which precipitation is not caused by visual observation when a dispersion in which the number average particle diameter is dispersed within a range of 5 to 20 nm is left at 25 ° C. for one week.

  The metal oxide particles are composed of primary particles and secondary particles formed by aggregation of the primary particles. Unless otherwise specified, the particle size means the particle size of the primary particles when the primary particles are not aggregated, and the particle size of the secondary particles when the primary particles are aggregated.

  A layer containing metal oxide particles may be used between the anode and the hole injection layer, between the hole injection layer and the hole transport layer, or between the hole transport layer and the light emitting layer. More preferably, it is desirable to use a layer containing metal oxide particles provided between the anode and the hole injection layer.

  The self-dispersing metal oxide particles according to the present invention can be prepared by oxidizing a metal carboxylate by a spray burner method with reference to US Pat. No. 7,879,303, US Pat. No. 7,212,236 and US Pat.

  The spray burner method is a method in which fine droplets formed by ejecting a metal precursor solution from a nozzle are oxidized by a high-temperature flame of a burner supplied with oxygen gas and combustible gas. As the combustible gas, methane gas is preferably used.

  The temperature of the flame is 600 ° C. or higher, preferably 1200 ° C. or higher, more preferably 1200 to 2600 ° C. A combustible gas can be supplied from the center of the burner and an oxygen gas can be supplied from the periphery to form a flame.

  Examples of the metal precursor include organic acid salts of metal and organometallic complexes. Examples of the organic acid include acetic acid, 2-ethylhexanoic acid, lauric acid, naphthenic acid, and other valent carboxylic acids. Examples of the organic ligand include acetylacetone. The metal precursor solution can be prepared by dissolving the metal precursor in an organic solvent.

  By using this production method, substantially spherical metal oxide particles having a number average particle diameter of 20 nm or less and uniform particle diameters can be produced. Further, the metal oxide particles produced using this method have self-dispersibility and can be dispersed in a solvent such as water or alcohol without using a dispersant. This self-dispersibility is presumed to be manifested because the surface of the metal oxide particles is modified with OH groups.

  The particle size (number average particle size) of the metal oxide particles is preferably in the range of 5 to 100 nm, and more preferably in the range of 5 to 20 nm. If it is 5 nm or more, it is easy to produce, and if it is 20 nm or less, the adjacent organic layer does not penetrate and uniform light emission without unevenness is obtained. More preferably, it is in the range of 5 to 15 nm, and particularly preferably in the range of 5 to 10 nm. Here, the particle size refers to a sphere-equivalent diameter of the same volume.

  The number average particle size of the metal oxide particles according to the present invention is measured by X-ray small angle scattering.

  Examples of the metal in the metal oxide particles according to the present invention include at least one metal element selected from Group 1 to Group 13 elements of the periodic table, such as molybdenum, tungsten, vanadium, rhenium, and the like. Copper is preferable, molybdenum and tungsten are more preferable, and tungsten is particularly preferable from the viewpoints of light emission luminance, driving voltage, and light emission lifetime.

  The metal oxide particles are contained in the functional layer A. For example, the functional layer A containing metal oxide particles can be used as the hole injection layer or the hole transport layer. Further, the metal oxide particles are dispersed and mixed in a known hole injection material or hole transport material solution to prepare a metal oxide particle-containing composition, and a hole injection layer or a hole transport layer is formed. be able to. At this time, the hole injection layer or the hole transport layer corresponds to the functional layer A according to the present invention.

  As a result of the inventor's ingenuity, by forming the functional layer A using the dispersion liquid of the self-dispersing metal oxide particles according to the present invention, it is possible to use a flexible substrate such as a heat-sensitive resin. In addition, the problems that occurred when using a dispersion of metal oxide particles with a dispersant could be solved.

  In addition, when the functional layer A is made of self-dispersing metal oxide particles, a dispersing agent is not necessary, the movement of holes between the metal oxide particles is easy, and the metal oxide and adjacent layers It is presumed that the light emission brightness is improved and the driving voltage is reduced due to the easy movement of holes between the adjacent layers due to the direct contact of the.

  In the functional layer A formed by adding self-dispersing metal oxide particles to a layer containing a hole transporting compound such as a hole injection layer or a hole transport layer, a metal oxide Since holes can be transmitted between the particles and the hole transporting compound without passing through the dispersant layer, it is presumed that the emission luminance is improved and the driving voltage is lowered.

《Wet process》
The functional layer A according to the present invention is preferably formed by a wet process from the viewpoint of mass production and the manifestation of the effects of the present invention.

  Examples of the wet process include coating methods such as a spin coating method, an ink jet method, a printing method, and a spray coating method.

  The metal oxide particle-containing composition used in the wet process can be prepared by dispersing the self-dispersing metal oxide particles in a solvent. As a solvent for dispersing the metal oxide particles, water or a polar solvent is preferable, and water or a lower alcohol is particularly preferable. Here, examples of the lower alcohol include methanol, ethanol, n-propanol, i-propanol, ni-butanol, t-butanol, or compounds in which the hydrogen atoms of their alkyl groups are partially or completely substituted with fluorine atoms. It is done. Among these lower alcohols, ethanol is particularly preferable from the viewpoints of dispersibility, electrode corrosivity, and drying properties.

  For example, a metal oxide particle-containing composition comprising a self-dispersing metal oxide particle and a solvent prepared by dispersing as described above is applied onto an anode such as ITO without containing an organic compound such as a polymer. By doing so, the functional layer A having excellent strength can be formed, and even if another functional layer is laminated thereon to produce an organic EL element, the functional layer A does not cohesively break and peel off. .

  It is presumed that this is because the bonding force was dramatically improved by the formation of hydrogen bonds between the particles and between the OH groups on the surface of the metal oxide particles. In addition, since self-dispersing metal oxide particles do not require a dispersing agent, cohesive failure in the phase of the dispersing agent or separation between the dispersing agent and the metal oxide particles is not a problem. it is conceivable that.

<< Each functional layer of organic EL element >>
Subsequently, the detail of the functional layer which comprises the organic EL element of this invention is demonstrated.

(1 Injection layer (hole injection layer, electron injection layer))
In the organic EL device of the present invention, the injection layer can be provided as necessary. The injection layer includes an electron injection layer and a hole injection layer, and may be present between the anode and the light emitting layer or the hole transport layer as described above, or between the cathode and the light emitting layer or the electron transport layer.

  The injection layer referred to in the present invention is a layer provided between the electrode and other functional layers in order to lower the driving voltage and improve the light emission luminance. “The organic EL element and the forefront of its industrialization (November 30, 1998, NTT) (Published by S. Co., Ltd.) ”, Chapter 2, Chapter 2,“ Electrode Materials ”(pages 123 to 166), which is described in detail, and includes a hole injection layer and an electron injection layer.

  Since the functional layer A containing the self-dispersing metal oxide particles according to the present invention can have a function as a hole injection layer, it may be laminated on the anode and used as the hole injection layer. Moreover, you may laminate | stack the following well-known hole injection layers on the said hole injection layer.

  The details of the known hole injection layer are described in, for example, JP-A Nos. 9-45479, 9-260062, and 8-288069, and can be applied to the hole injection layer. As hole injection materials, triazole derivatives, oxadiazole derivatives, imidazole 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 polymers containing stilbene derivatives, silazane derivatives, aniline copolymers, polyarylalkane derivatives, or conductive polymers, preferably polythiophene derivatives (such as poly (3,4-ethylenedioxythiophene)), polyaniline derivatives. Body, polypyrrole derivatives, and the like, still more preferably polythiophene derivative.

  Furthermore, the hole injection layer preferably contains an acidic substance as a dopant. Examples of the acidic substance include metal halides, organic acids (such as polystyrene sulfonic acid), and Lewis acids. The self-dispersing metal oxide particles according to the present invention may be mixed with the hole injection material to form the hole injection layer that is the functional layer A according to the present invention.

  Details of the electron injection layer are described in, for example, JP-A-6-325871, JP-A-9-17574, and JP-A-10-74586, and specifically, strontium, aluminum and the like are representative. A metal buffer layer, an alkali metal compound buffer layer typified by lithium fluoride, an alkaline earth metal compound buffer layer typified by magnesium fluoride, and an oxide buffer layer typified by aluminum oxide. In the present invention, the buffer layer (injection layer) is desirably a very thin film, and potassium fluoride and sodium fluoride are preferable. The layer thickness is about 0.1 nm to 5 μm, preferably 0.1 to 100 nm, more preferably 0.5 to 10 nm, and most preferably 0.5 to 4 nm.

(2 hole transport layer)
As the hole transport material constituting the hole transport layer, the same compounds as those applied in the hole injection layer can be used, and further, porphyrin compounds, aromatic tertiary amine compounds, and styryl. It is preferable to use an amine 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 two more described in US Pat. No. 5,061,569. Having a condensed aromatic ring of, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-308 88,4 ', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units are linked in a three star burst form ( 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-4-297076, JP-A-2000-196140, JP-A-2001-102175, J. Pat. Appl. Phys. , 95, 5773 (2004), JP-A-11-251067, J. MoI. Huang et. al. It is also possible to use a hole transport material that has a so-called p-type semiconducting property as described in the literature (Applied Physics Letters 80 (2002), p. 139), JP 2003-519432 A. it can.

  The hole transport layer is 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. Can do. Although there is no restriction | limiting in particular about the layer thickness of a positive hole transport layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5-200 nm. The hole transport layer may have a single layer structure composed of one or more of the above materials.

  Hereinafter, although the preferable specific example ((1)-(75)) of the compound used for the positive hole transport material of the organic EL element of this invention is given, this invention is not limited to these.

  Note that n described in the above exemplary compounds represents the degree of polymerization, and preferably represents an integer having a weight average molecular weight in the range of 50,000 to 200,000. When the weight average molecular weight is 50,000 or more, the solubility in a solvent is appropriate, and the light emitting efficiency is high without being mixed with other layers during film formation. When the weight average molecular weight is 200,000 or less, synthesis and purification are easy. When the molecular weight distribution is small, the remaining amount of impurities is small, and the light emission efficiency, voltage, and life of the organic EL element are improved.

  These polymer compounds are disclosed in Makromol. Chem. , Pages 193, 909 (1992) and the like.

(3 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 cathode side with respect to the light emitting layer is injected from the cathode. As long as it has a function of transmitting electrons to the light-emitting layer, any material can be selected and used from among conventionally known compounds. For example, fluorene derivatives, carbazole derivatives, azacarbazole Examples thereof include metal complexes such as derivatives, oxadiazole derivatives, triazole derivatives, silole derivatives, pyridine derivatives, pyrimidine derivatives, and 8-quinolinol derivatives.

  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 transport material.

  Among these, a carbazole derivative, an azacarbazole derivative, a pyridine derivative, and the like are preferable in the present invention, and an azacarbazole derivative is more preferable.

  The electron transport layer can be formed by thinning the electron transport material by a known method such as a spin coating method, a casting method, a printing method including an ink jet method, an LB method, and the like, preferably The electron transport material can be formed by a wet process using a coating solution containing a fluorinated alcohol solvent.

  Although there is no restriction | limiting in particular about the layer thickness of an electron carrying layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5-200 nm. The electron transport layer may have a single layer structure composed of one or more of the above materials.

  Alternatively, an electron transport layer with high n property doped with impurities as a guest material can 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.

  The electron transport layer in the present invention may contain an organic alkali metal salt. There are no particular restrictions on the type of organic substance, but carbonate, formate, acetate, propionic acid, butyrate, valerate, caprate, enanthate, caprylate, oxalate, malonate, Succinate, benzoate, phthalate, isophthalate, terephthalate, salicylate, pyruvate, lactate, malate, adipate, mesylate, tosylate, benzenesulfonate Preferably, formate, acetate, propionate, butyrate, valerate, caprate, enanthate, caprylate, oxalate, malonate, succinate, benzoate More preferably, alkali metal salts of aliphatic carboxylic acids such as formate, acetate, propionate and butyrate are preferable, and the number of carbon atoms of the aliphatic carboxylic acid is preferably 4 or less. Most preferred is acetate.

  The kind of alkali metal of the organic alkali metal salt is not particularly limited, and examples thereof include Na, K, and Cs, preferably K, Cs, and more preferably Cs. Examples of the alkali metal salt of the organic substance include a combination of the organic substance and the alkali metal, preferably, Li carbonate, Na carbonate, K carbonate, C carbonate, Li formate, K formate, Na formate, C formate, Li acetate, acetic acid. K, Na acetate, Cs acetate, Li propionate, Na propionate, K propionate, K propionate, Li oxalate, Na oxalate, K oxalate, Cs, Li malonate, Na malonate, malonic acid K, malonic acid Cs, succinic acid Li, succinic acid Na, succinic acid K, succinic acid Cs, benzoic acid Li, benzoic acid Na, benzoic acid K, benzoic acid Cs, more preferably Li acetate, acetic acid K, Na acetate, Acetic acid Cs, most preferably acetic acid Cs.

  The content of these dope materials is preferably 1.5 to 35% by mass, more preferably 3 to 25% by mass, and most preferably 5 to 15% by mass with respect to the electron transport layer to be added.

(4 light emitting layer)
The light emitting layer constituting the organic EL device of 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. It may be in the layer or the interface between the light emitting layer and the adjacent layer.

  The light emitting layer according to the present invention is not particularly limited in its configuration as long as the contained light emitting material satisfies the above requirements. Moreover, there may be a plurality of layers having the same emission spectrum and emission maximum wavelength. It is preferable to have a non-light emitting intermediate layer between each light emitting layer.

  When the light emitting layer in this invention consists of a several layer, it is preferable that the sum total of the layer thickness exists in the range of 1-100 nm, More preferably, since a lower drive voltage can be obtained, it is 50 nm or less. In addition, the sum total of the layer thickness of the light emitting layer as used in the field of this invention is a layer thickness also including the said intermediate | middle layer, when a nonluminous intermediate | middle layer exists between light emitting layers.

  The thickness of each light emitting layer is preferably adjusted to a range of 1 to 50 nm. When the blue, green, and red light emitting layers are stacked, there is no particular limitation on the relationship between the thicknesses of the light emitting layers. For the production of the light emitting layer, a light emitting material or a host compound, which will be described later, is formed by forming a film by a known thinning method such as a vacuum deposition method, a spin coating method, a casting method, an LB method, an ink jet method, or the like. it can.

  In the present invention, a plurality of light emitting materials may be mixed in each light emitting layer, or a phosphorescent light emitting material and a fluorescent light emitting material may be mixed and used in the same light emitting layer. In the present invention, the structure of the light-emitting layer preferably contains a host compound and a light-emitting material (also referred to as a light-emitting dopant) and emits light from the light-emitting material.

  The total thickness of the light emitting layer is not particularly limited, but from the viewpoint of improving the stability of the emission color against the driving current and the uniformity of the film, preventing unnecessary application of high voltage during light emission. It is preferable to adjust in the range of 2 nm to 5 μm, more preferably in the range of 2 to 200 nm, and particularly preferably in the range of 10 to 100 nm.

  The light emitting layer of the organic EL device of the present invention can contain a light emitting dopant (such as a phosphorescent light emitting dopant or a fluorescent light emitting dopant) compound and a host compound.

(4.1 Luminescent dopant)
As the light-emitting dopant according to the present invention, a fluorescent light-emitting dopant or a phosphorescent light-emitting dopant (also referred to as a phosphorescent compound or a phosphorescent light-emitting compound) can be used, and a phosphorescent light-emitting dopant is preferable.

(4.1.1 Phosphorescence emission dopant)
As the light emitting dopant, a phosphorescent light emitting dopant (also referred to as a phosphorescent compound) is preferable because high luminous efficiency can be obtained. A phosphorescent dopant is a compound in which light emission from an excited triplet is observed, and is a compound having a phosphorescence quantum yield of 0.01 or more at 25 ° C. Preferably it is 0.1 or more. In this invention, the compound contained in a light emitting layer other than a light emitting dopant is made into a host compound.

  In addition, the ratio of the host compound and phosphorescence emission dopant in a light emitting layer will be what ratio if it is between 1-99 mass% in each compound, when the mass of the compound contained in the whole light emitting layer is 100%. However, it is preferable that the ratio of the host compound is larger than that of the phosphorescent dopant, and more preferably the ratio of the phosphorescent dopant is 1 to 30% by mass.

  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 emission dopant used in the present invention is a compound that achieves the phosphorescence quantum yield in any solvent. .

  There are two types of light emission principles of phosphorescent dopants. One is the recombination of carriers on the host compound to which carriers are transported, generating an excited state of the host compound, and this energy is used as the phosphorescent dopant. It is an energy transfer type in which light emission from a phosphorescent dopant is obtained by moving it. The other is a carrier trap type in which a phosphorescent dopant becomes a carrier trap, and recombination of carriers occurs on the phosphorescent dopant and light emission from the phosphorescent dopant is obtained. In either case, it is a condition that the excited state energy of the phosphorescent dopant is lower than the excited state energy of the host compound.

  The phosphorescent light-emitting dopant can be appropriately selected from known materials used for the light-emitting layer of the organic EL device, but is preferably a complex compound containing a group 8-10 metal in the periodic table of elements. More preferred are iridium compounds, osmium compounds, platinum compounds (platinum complex compounds), and rare earth complexes, and most preferred are iridium compounds.

  The phosphorescent dopant according to the present embodiment preferably contains at least one blue phosphorescent material, more preferably at least one blue phosphorescent material, and has a band gap energy higher than that of the blue phosphorescent material. Low at least two phosphorescent materials.

  Below, the phosphorescence dopant which can be used as a material of a light emitting layer in this invention is demonstrated.

  As a phosphorescence emission dopant which can be used by this invention, the compound represented with the following general formula (B) is preferable.

In general formula (B), ring Am, ring An, ring Bm and ring Bn represent a 5-membered or 6-membered aromatic hydrocarbon ring or aromatic heterocycle, and Ar represents an aromatic hydrocarbon ring or aromatic heterocycle. Represents a non-aromatic hydrocarbon ring or a non-aromatic heterocyclic ring. R _1m , R _2m , R _1n and R _2n are each independently an alkyl group having 2 or more carbon atoms, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group. And may further have a substituent. Ra, Rb and Rc are each independently a hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, heteroaryl group, non-aromatic It represents a hydrocarbon ring group or a non-aromatic heterocyclic group, may further have a substituent, and Ra may form a ring with Ar. na and nc represent 1 or 2, and nb represents an integer of 1 to 4. m represents 1 or 2, n represents 1 or 2, and m + n is 3. Note that the structures of the three ligands coordinated to Ir are not all the same.

  In the general formula (B), examples of the 5-membered or 6-membered aromatic hydrocarbon ring represented by the ring An, the ring Am, the ring Bn, and the ring Bm include a benzene ring.

  In the general formula (B), examples of the 5-membered or 6-membered aromatic heterocycle represented by ring An, ring Am, ring Bn and ring Bm include a furan ring, a thiophene ring, an oxazole ring, a pyrrole ring, and pyridine. A ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, an oxadiazole ring, a triazole ring, an imidazole ring, a pyrazole ring, a thiazole ring, and the like.

  Preferably, at least one of ring Bn and ring Bm is a benzene ring, more preferably at least one of ring An and ring Am is a benzene ring.

  In the general formula (B), examples of the aromatic hydrocarbon ring represented by Ar include a benzene ring, biphenyl ring, naphthalene ring, azulene ring, anthracene ring, phenanthrene ring, pyrene ring, chrysene ring, naphthacene ring, and 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, pyranthrene ring, anthraanthrene ring and the like.

  In the general formula (B), examples of the aromatic heterocycle represented by Ar include a silole ring, a furan ring, a thiophene ring, an oxazole ring, a pyrrole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, and a triazine ring. Oxadiazole ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indole ring, benzimidazole ring, benzthiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring, phthalazine ring, thienothiophene ring, carbazole ring, aza A carbazole ring (representing any one or more of the carbon atoms constituting the carbazole ring replaced by a nitrogen atom), a dibenzosilole ring, a dibenzofuran ring, a dibenzothiophene ring, a benzothiophene ring or a dibenzofuran ring. Any one Ring substituted with nitrogen atom, benzodifuran ring, benzodithiophene ring, acridine ring, benzoquinoline ring, phenazine ring, phenanthridine ring, phenanthroline ring, cyclazine ring, quindrine ring, tepenidine ring, quinindrin ring, triphenodithia Gin ring, triphenodioxazine ring, phenanthrazine ring, anthrazine ring, perimidine ring, naphthofuran ring, naphthothiophene ring, naphthodifuran ring, naphthodithiophene ring, anthrafuran ring, anthradifuran ring, anthrathiophene ring, anthradithiophene Ring, thianthrene ring, phenoxathiin ring, dibenzocarbazole ring, indolocarbazole ring, dithienobenzene ring and the like.

  In the general formula (B), examples of the non-aromatic hydrocarbon ring represented by Ar include cycloalkane (eg, cyclopentane ring, cyclohexane ring, etc.), cycloalkoxy group (eg, cyclopentyloxy group, cyclohexyloxy group). Etc.), a cycloalkylthio group (for example, a cyclopentylthio group, a cyclohexylthio group, etc.), a cyclohexylaminosulfonyl group, a tetrahydronaphthalene ring, a 9,10-dihydroanthracene ring, a biphenylene ring and the like.

  In the general formula (B), examples of the non-aromatic heterocycle represented by Ar include an epoxy ring, an aziridine ring, a thiirane ring, an oxetane ring, an azetidine ring, a thietane ring, a tetrahydrofuran ring, a dioxolane ring, a pyrrolidine ring, and a pyrazolidine. Ring, imidazolidine ring, oxazolidine ring, tetrahydrothiophene ring, sulfolane ring, thiazolidine ring, ε-caprolactone ring, ε-caprolactam ring, piperidine ring, hexahydropyridazine ring, hexahydropyrimidine ring, piperazine ring, morpholine ring, tetrahydropyran Ring, 1,3-dioxane ring, 1,4-dioxane ring, trioxane ring, tetrahydrothiopyran ring, thiomorpholine ring, thiomorpholine-1,1-dioxide ring, pyranose ring, diazabicyclo [2,2,2]- Octane ring, Fe Examples thereof include a noxazine ring, a phenothiazine ring, an oxanthrene ring, a thioxanthene ring, and a phenoxathiin ring.

  In the general formula (B), these rings represented by Ar may have a substituent, and the substituents may be bonded to each other to form a ring.

  In the general formula (B), Ar is preferably an aromatic hydrocarbon ring or an aromatic heterocyclic ring, more preferably an aromatic hydrocarbon ring, and still more preferably a benzene ring.

In the general formula (B), examples of the alkyl group represented by R _1m and R _2m include a methyl group, an ethyl group, a trifluoromethyl group, an isopropyl group, an n-butyl group, a t-butyl group, and an n-hexyl group. Group, 2-methylhexyl group, pentyl group, adamantyl group, n-decyl group, n-dodecyl group and the like.

In the general formula (B), the aromatic hydrocarbon ring group, aromatic heterocyclic group, non-aromatic hydrocarbon ring group or non-aromatic heterocyclic group represented by R _1m and R _2m is the above-described general formula. Examples thereof include a monovalent group derived from an aromatic hydrocarbon ring, an aromatic heterocyclic ring, a non-aromatic hydrocarbon ring or a non-aromatic heterocyclic ring represented by Ar in (B).

In general formula (B), an alkyl group having 2 or more carbon atoms, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group, or a non-aromatic heterocyclic ring represented by R _1m and R _2m Examples of the substituent that the group may further have include, for example, a halogen atom, a cyano group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an amino group, a silyl group, an arylalkyl group, an aryl group, and a heteroaryl group. , Non-aromatic hydrocarbon ring group, non-aromatic heterocyclic group and the like.

In general formula (B), it is preferable that both R _1m and R _2m are alkyl groups or cycloalkyl groups having 2 or more carbon atoms, and either R _1m or R _2m has 3 or more carbon atoms. The branched alkyl group is also preferable. More preferably, both R _1m and R _2m are branched alkyl groups having 3 or more carbon atoms.

In General Formula (B), R _1n and R _2n have the same _{meanings as} R _1m and R _2m in General Formula (B) described above.

  In the general formula (B), the aryl group and heteroaryl group represented by Ra, Rb and Rc are derived from the aromatic hydrocarbon ring and aromatic heterocycle represented by Ar in the general formula (B). And a monovalent group.

  In the general formula (B), as the non-aromatic hydrocarbon ring group and non-aromatic heterocyclic group represented by Ra, Rb and Rc, the non-aromatic carbon represented by Ar in the above-mentioned general formula (B) And monovalent groups derived from a hydrogen ring and a non-aromatic heterocyclic ring.

  The iridium complex compound represented by the general formula (B) is preferably represented by the following general formula (C).

In general formula (C), Ar represents an aromatic hydrocarbon ring, an aromatic heterocyclic ring, a non-aromatic hydrocarbon ring or a non-aromatic heterocyclic ring. R _1m , R _2m , R _1n and R _2n are each independently an alkyl group having 2 or more carbon atoms, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group. And may further have a substituent. Ra and Rc are each independently a hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, heteroaryl group, non-aromatic hydrocarbon Represents a cyclic group or a non-aromatic heterocyclic group, may further have a substituent, and Ra may form a ring with Ar. na and nc represent 1 or 2. m represents 1 or 2, n represents 1 or 2, and m + n is 3. Note that the structures of the three ligands coordinated to Ir are not all the same.

In the general formula (C), Ar, R _1m , R _2m , R _1n , R _2n , Ra, Rc, na, nc, m, and n are Ar, R _1m , R _2m , R _1n in the general formula (B). , R _2n , Ra, Rc, na, nc, m and n.

  The iridium complex compounds represented by the general formulas (B) and (C) preferably used in the present invention can be synthesized by referring to known methods described in International Publication No. 2006/121811, etc. .

  The iridium complex compound represented by the general formula (C) is preferably represented by the following general formula (D).

In general formula (D), R _1m , R _2m , R _1n and R _2n are each independently an alkyl group having 2 or more carbon atoms, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, or a non-aromatic hydrocarbon ring group. Alternatively, it represents a non-aromatic heterocyclic group and may further have a substituent. Ra, Rc and Rd are each independently a hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, heteroaryl group, non-aromatic It represents a hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent. na and nc represent 1 or 2, and nd represents an integer of 1 to 5. m represents 1 or 2, n represents 1 or 2, and m + n is 3. Note that the structures of the three ligands coordinated to Ir are not all the same.

In General Formula (D), R _1m , R _2m , R _1n , R _2n , Ra, Rc, na, nc, m, and n are R _1m , R _2m , R _1n , R _2n , R in General Formula (B), It is synonymous with Ra, Rc, na, nc, m and n.

  In the general formula (D), Rd has the same meaning as Ra, Rb and Rc in the general formula (B).

  The iridium complex compound represented by the general formula (B) is preferably represented by the following general formula (E).

In general formula (E), R _1m , R _2m , R _1n and R _2n are each independently an alkyl group having 2 or more carbon atoms, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, or a non-aromatic hydrocarbon ring group. Alternatively, it represents a non-aromatic heterocyclic group and may further have a substituent. Ra, Rc and Rd are each independently a hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, heteroaryl group, non-aromatic It represents a hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent. na and nc represent 1 or 2, and nd represents an integer of 1 to 4. X represents O, S, SiRz ₁ Rz ₂ , NRz ₁ or CRz ₁ Rz ₂ , and Rz ₁ and Rz ₂ are an alkyl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, and a non-aromatic hydrocarbon ring group. Or represents a non-aromatic heterocyclic group. m represents 1 or 2, n represents 1 or 2, and m + n is 3.

In General Formula (E), R _1m , R _2m , R _1n , R _2n , Ra, Rc, na, nc, m, and n are R _1m , R _2m , R _1n , R _2n , R in General Formula (B), It is synonymous with Ra, Rc, na, nc, m and n.

  In the general formula (E), Rd has the same meaning as Ra, Rb and Rc in the general formula (B).

In X in the general formula (E), the aromatic hydrocarbon ring group, aromatic heterocyclic group, non-aromatic hydrocarbon ring group or non-aromatic heterocyclic group represented by Rz ₁ and Rz ₂ is And monovalent groups derived from an aromatic hydrocarbon ring, aromatic heterocycle, non-aromatic hydrocarbon ring, or non-aromatic hydrocarbon ring represented by Ar in the formula (B).

  The iridium complex compound represented by the general formula (B) is preferably represented by the following general formula (F).

In general formula (F), R _1m , R _2m , R _1n and R _2n are each independently an alkyl group having 2 or more carbon atoms, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, or a non-aromatic hydrocarbon ring group. Alternatively, it represents a non-aromatic heterocyclic group and may further have a substituent. Ra, Rc and Rd are each independently a hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, heteroaryl group, non-aromatic It represents a hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent. na and nc represent 1 or 2, and nd represents an integer of 1 to 4. X represents O, S, SiRz ₁ Rz ₂ , NRz ₁ or CRz ₁ Rz ₂ , and Rz ₁ and Rz ₂ are an alkyl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, and a non-aromatic hydrocarbon ring group. Or represents a non-aromatic heterocyclic group. m represents 1 or 2, n represents 1 or 2, and m + n is 3.

In the general formula (F), R _1m , R _2m , R _1n , R _2n , Ra, Rc, na, nc, m, and n are R _1m , R _2m , R _1n , R _2n , R in the general formula (B), It is synonymous with Ra, Rc, na, nc, m and n.

  In the general formula (F), Rd has the same meaning as Ra, Rb and Rc in the general formula (B).

  In general formula (F), X is synonymous with X in general formula (E).

  Below, the specific compound of the phosphorescence emission dopant which can be preferably used by this invention is illustrated. However, the present invention is not limited to these.

(4.1.2 Combined use with conventionally known dopants)
Moreover, the said light emission dopant may be used in combination of a multiple types of compound, and may use it combining the phosphorescence dopants from which structures differ, and combining a phosphorescence dopant and a fluorescence dopant.

  Here, although the specific example of the conventionally well-known light emission dopant which may be used in combination with the iridium complex compound represented by the said general formula (B) as a light emission dopant is given, this invention is not limited to these.

(4.2 Host compound)
(4.2.1 Host compound represented by formula (A))
As a host compound used by this invention, the compound represented by the following general formula (A) is preferable.

  In the general formula (A), X represents NR ′, O, S, CR′R ″ or SiR′R ″. R ′ and R ″ each represent a hydrogen atom or a substituent. Ar represents an aromatic ring. N represents an integer of 0 to 8.

  In the general formula (A), the substituents represented by R ′ and R ″ in NR ′, CR′R ″ or SiR′R ″ represented by X are each an alkyl group (for example, methyl group, ethyl Group, propyl group, isopropyl group, t-butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, etc.), cycloalkyl group (for example, cyclopentyl group, cyclohexyl group etc.), Alkenyl group (for example, vinyl group, allyl group, etc.), alkynyl group (for example, ethynyl group, propargyl group, etc.), aromatic hydrocarbon ring group (aromatic carbocyclic group, aryl group, etc., for example, phenyl group, p-chlorophenyl, mesityl, tolyl, xylyl, naphthyl, anthryl, azulenyl, acenaphthenyl, fluoreni Group, phenanthryl group, indenyl group, pyrenyl group, biphenylyl group, etc.), aromatic heterocyclic group (for example, pyridyl group, pyrimidinyl group, furyl group, pyrrolyl group, imidazolyl group, benzimidazolyl group, pyrazolyl group, 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, furazanyl Group, thienyl group, quinolyl group, benzofuryl group, dibenzofuryl group, benzothienyl group, dibenzothienyl group, indolyl group, carbazolyl group, carbolinyl group, diazacarbazolyl group (the carbon atom constituting the carboline ring of the carbolinyl group) One is replaced by a nitrogen atom ), Quinoxalinyl group, pyridazinyl group, triazinyl group, quinazolinyl group, phthalazinyl group, etc.), non-aromatic heterocyclic group (for example, 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 (for example, phenoxy group, Naphthyloxy group, etc.), alkylthio group (eg, methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group, etc.), cycloalkylthio group (eg, cyclopentylthio group, cyclohexyl). Ruthio group, etc.), arylthio group (eg, phenylthio group, naphthylthio group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.) An aryloxycarbonyl group (eg, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), a sulfamoyl group (eg, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexyl) Aminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group Group), 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 (eg acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group etc.), amide group (eg methylcarbonylamino) Group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethylhexyl Sulfonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc.), carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl 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, octylureido group, dodecylureido group, phenylureido Naphthylureido group, 2-pyridylaminoureido group, etc.), sulfinyl group (for example, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group, naphthylsulfinyl) Group, 2-pyridylsulfinyl group, etc.), alkylsulfonyl group (eg, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc.), arylsulfonyl group or heteroaryl Sulfonyl group (for example, phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl 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 atom (for example, fluorine atom, chlorine atom, bromine atom, etc.) ), Fluorinated hydrocarbon group (eg, fluoromethyl group, trifluoromethyl group, pentafluoroethyl group, pentafluorophenyl group, etc.), cyano group, nitro group, hydroxy group, mercapto group, silyl group (eg, trimethylsilyl group) , Triisopropylsilyl group, triphenylsilyl group, phenyldiethylsilyl group, etc.). These substituents may be further substituted with the above substituents. A plurality of these substituents may be bonded to each other to form a ring.

  Among them, X is preferably NR ′ or O, and R ′ is an aromatic hydrocarbon group (also referred to as aromatic carbocyclic group, aryl group, etc., for example, phenyl group, p-chlorophenyl group, mesityl group, A tolyl group, a xylyl group, a naphthyl group, an anthryl group, an azulenyl group, an acenaphthenyl group, a fluorenyl group, a phenanthryl group, an indenyl group, a pyrenyl group, a biphenylyl group), or an aromatic heterocyclic group (for example, a furyl group, a thienyl group, a pyridyl group) Group, pyridazinyl group, pyrimidinyl group, pyrazinyl group, triazinyl group, imidazolyl group, pyrazolyl group, thiazolyl group, quinazolinyl group, phthalazinyl group and the like are particularly preferable.

  The above aromatic hydrocarbon group and aromatic heterocyclic group each may have a substituent represented by R ′ and R ″ in the general formula (A).

  In the general formula (A), examples of the aromatic ring represented by Ar include an aromatic hydrocarbon ring and an aromatic heterocyclic ring. The aromatic ring may be a single ring or a condensed ring, and may be unsubstituted, or may have a substituent represented by R ′ or R ″ in the general formula (A). Good.

  In the general formula (A), examples of the aromatic hydrocarbon ring represented by Ar include a benzene ring, biphenyl ring, naphthalene ring, azulene ring, anthracene ring, phenanthrene ring, pyrene ring, chrysene ring, naphthacene ring, and 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, pyranthrene ring, anthraanthrene ring and the like. These rings may further have substituents represented by R ′ and R ″ in the general formula (A).

  In the general formula (A), examples of the aromatic heterocycle represented by Ar include a furan ring, a dibenzofuran ring, a thiophene ring, an oxazole ring, a pyrrole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, and a triazine ring. , 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), etc. Can be mentioned.

  These rings may further have substituents represented by R ′ and R ″ in the general formula (A).

  Among the above, in the general formula (A), the aromatic ring represented by Ar is preferably a carbazole ring, carboline ring, dibenzofuran ring, or benzene ring, and more preferably a carbazole ring, carboline ring, or benzene ring. More preferred is a benzene ring having a substituent, and particularly preferred is a benzene ring having a carbazolyl group.

  In the general formula (A), each of the aromatic rings represented by Ar is preferably a condensed ring having 3 or more rings, and the aromatic hydrocarbon condensed ring in which 3 or more rings are condensed is a specific example. Naphthacene ring, anthracene ring, tetracene ring, pentacene ring, hexacene ring, phenanthrene ring, pyrene ring, benzopyrene ring, benzoazulene ring, chrysene ring, benzochrysene ring, acenaphthene ring, acenaphthylene ring, triphenylene ring, coronene ring, benzocoronene Ring, hexabenzocoronene ring, fluorene ring, benzofluorene ring, fluoranthene ring, perylene ring, naphthoperylene ring, pentabenzoperylene ring, benzoperylene ring, pentaphen ring, picene ring, pyrantolen ring, coronene ring, naphthocolonene ring, ovalen ring, Anthracanthrene rings It is. In addition, these rings may further have the above substituent.

  Specific examples of the aromatic heterocycle condensed with three or more rings include an acridine ring, a benzoquinoline ring, a carbazole ring, a carboline ring, a phenazine ring, a phenanthridine ring, a phenanthroline ring, a carboline ring, a cyclazine ring, Kindin ring, tepenidine ring, quinindrin ring, triphenodithiazine ring, triphenodioxazine ring, phenanthrazine ring, anthrazine ring, perimidine ring, diazacarbazole ring (any one of the carbon atoms constituting the carboline ring is a nitrogen atom Phenanthroline ring, dibenzofuran ring, dibenzothiophene ring, naphthofuran ring, naphthothiophene ring, benzodifuran ring, benzodithiophene ring, naphthodifuran ring, naphthodithiophene ring, anthrafuran ring, anthradifuran ring , Emissions tiger thiophene ring, anthradithiophene ring, thianthrene ring, phenoxathiin ring, such as thio fan train ring (naphthothiophene ring). In addition, these rings may further have a substituent.

  Moreover, in general formula (A), although n represents the integer of 0-8, it is preferable that it is 0-2, and when X is O and S especially, it is preferable that it is 1-2.

  In the present invention, a low molecular compound having both a dibenzofuran ring and a carbazole ring is particularly preferable.

  Specific examples of host compounds that can be used in the present invention are shown below. However, the present invention is not limited to these.

(4.2.2 Combined use with conventionally known host compounds)
In addition, the host compound used in the present invention may be used in combination of a plurality of types of compounds. By using a plurality of types of host compounds, the mobility (amount of movement) of charges (holes and / or electrons) can be adjusted, and the light emission efficiency of the organic EL element 100 can be improved.

  As the host compound that may be used in combination with the host compound represented by the general formula (A), a known host compound can be used.

  In this invention, there is no restriction | limiting in particular as a host compound which can be used together, The compound conventionally used with an organic EL element can be used. Typically, a carbazole derivative, a triarylamine derivative, an aromatic derivative, a nitrogen-containing heterocyclic compound, a thiophene derivative, a furan derivative, an oligoarylene compound or the like having a basic skeleton, or a carboline derivative or a diazacarbazole derivative (here And the diazacarbazole derivative represents one in which at least one carbon atom of the hydrocarbon ring constituting the carboline ring of the carboline derivative is substituted with a nitrogen atom.

  As the known host compound that can be used in the present invention, 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.

  In addition, by using three or more known compounds used as phosphorescent light emitting dopants, a white luminescent color with good color rendering can be obtained.

  The host compound used in the present invention may be a 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 (polymerizable light emitting host compound). Alternatively, two or more of these compounds may be used.

  Specifically, the host compound preferably has a carbazole skeleton, a triarylamine skeleton, a thiophene skeleton, a furan skeleton, a carboline skeleton, or a diazacarbazole skeleton, and has a carbazole skeleton, a thiophene skeleton, or a furan skeleton. Is more 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.

  The light emitting layer preferably contains a low molecular weight host compound, and is a low molecular weight compound that does not contain a repeating unit having a molecular weight of 3000 or less from the viewpoint of the ease of material synthesis and the solvent content during film formation. preferable. More preferably, it is the range of 200-2000, More preferably, it is the range of 400-1500. When the molecular weight is 3000 or less, not only the material synthesis is facilitated and the manufacturing cost is reduced, but also the solvent is not easily taken into the voids between the molecules, the light emission is stabilized, and the heat generated during driving and the temperature during storage are not easily affected. Thus, the reliability of light emission is improved.

  “Molecular weight” as used herein is obtained using a conventionally known mass spectrum. For polymers (for example, those having a molecular weight of 10,000 or more), a conventionally known GPC (gel permeation chromatography) is used. It is measured.

  The light emitting layer is preferably formed by a wet process because the light emitting dopant is a layer containing the light emitting dopant uniformly. In the present invention, the wet process is preferably film formation by a coating method such as a spin coating method, an ink jet method, a printing method, or a spray coating method.

  The electron transport layer of the present invention is preferably formed by a wet process.

  Examples of the liquid medium for dissolving or dispersing the organic EL device material according to the present invention include ketones such as methyl ethyl ketone and cyclohexanone, and fatty acid esters such as ethyl acetate, isopropyl acetate, propylene glycol monomethyl ether acetate, and 3-methoxybutyl acetate. , Halogenated hydrocarbons such as dichlorobenzene, aromatic hydrocarbons such as toluene, xylene, mesitylene and cyclohexylbenzene, non-fluorinated alcohols such as methanol, ethanol, propanol and isopropanol, trifluoroethanol (TFEO), tetra Fluorinated alcohols such as fluoropropanol (TFPO) and hexafluoropropanol (HFPO), aliphatic hydrocarbons such as cyclohexane, decalin and dodecane, DMF, DMSO, etc. Although solvent can be used, from the suppression of the solvent amount contained in the device, the boiling point is preferably used is a solvent in the range of 50 ° C. to 180 ° C.. 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.

In the present invention, the content of the solvent contained in the organic EL element is preferably in the range of 0.01 to 1 μg / cm ² . In the case of 0.01 μg or more, the organic film becomes nectar, so that the voltage can be lowered when the element is driven. In the case of 1 μg / cm ² or less, the substance diffusion is prevented when the element is driven and the light emitting material is aggregated. By preventing this, high efficiency and a long driving life can be achieved. These solvent contents can be determined by temperature programmed desorption gas spectroscopy.

(5 anode)
As the anode constituting the organic EL device, 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 materials 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 desired shape pattern may be formed by a photolithography method, or when pattern accuracy is not so high (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. Furthermore, although it depends on the material, the layer thickness is usually in the range of 10 to 1000 nm, preferably in the range of 10 to 200 nm.

(6 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, Magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred. 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 the cathode is preferably several hundred Ω / □ or less, and the layer thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 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 emission luminance is advantageously improved.

  Moreover, after producing the metal with a layer thickness of 1 to 20 nm on the cathode, a transparent or translucent cathode can be produced by forming the conductive transparent material mentioned in the description of the anode on the cathode, By applying this, an organic EL element in which both the anode and the cathode are transmissive can be produced.

(7. Support substrate)
The 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 is not particularly limited in the type of glass, plastic, etc., and is transparent. Or 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. Since the effect of suppressing high-temperature storage stability and chromaticity variation appears greatly in a flexible substrate than a rigid substrate, a particularly preferable support substrate has flexibility that can give flexibility to an organic EL element. Resin film.

  Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate (TAC), cellulose acetate butyrate, cellulose acetate propionate ( CAP), cellulose esters such as cellulose acetate phthalate, 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.

An inorganic film, an organic film, or a hybrid film of both may be formed on the surface of the resin film, and the 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 permeation measured by a method based on JIS K 7126-1987. The film is preferably a high barrier film having a degree of 10 ⁻³ cm ³ / (m ² · 24 h · atm) or less and a water vapor transmission rate of 10 ⁻³ g / (m ² · 24 h) or less. More preferably, the degree is 10 ⁻⁵ g / (m ² · 24 h) or less.

  As a material for forming the barrier film, any material may be used as long as it has a function of suppressing entry of factors that cause deterioration of the organic EL element such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like is used. Can do. 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 a functional 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.

  In the organic EL device of the present invention, the external extraction efficiency of light emission at room temperature 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.

(8. Sealing adhesive, sealing member)
As a sealing means applicable to the organic EL element of the present invention, for example, a method of adhering a sealing member, an electrode, and a support substrate with an adhesive can be mentioned.

  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, silicone, 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 cm ³ / (m ² · 24 h · atm) or less, according to JIS K 7129-1992. The water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) measured by the above method is preferably 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 photo-curing and thermosetting adhesives having reactive vinyl groups such as acrylic acid oligomers and methacrylic acid oligomers, and moisture curing adhesives such as 2-cyanoacrylates. Can be mentioned. 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. Further, 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 functional layer are coated on the outer side of the electrode facing the support substrate with the functional 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, ion plating, plasma polymerization, atmospheric pressure plasma A combination method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used.

  In order to form a gas phase and a liquid phase in the gap between the sealing member and the display area of the organic EL element, an inert gas such as nitrogen or argon, an inert gas such as fluorinated hydrocarbon or silicon oil is used. It is preferable to inject a liquid. 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.

  Sealing includes casing type sealing (can sealing) and close contact type sealing (solid sealing), but solid sealing is preferable from the viewpoint of thinning. Moreover, when producing a flexible organic EL element, since sealing is also required for the sealing member, solid sealing is preferable.

  Below, the preferable aspect in the case of performing solid sealing is demonstrated.

  As the sealing adhesive according to the present invention, a thermosetting adhesive, an ultraviolet curable resin, or the like can be used, but preferably a thermosetting adhesive such as an epoxy resin, an acrylic resin, or a silicone resin, more preferably moisture resistant. It is an epoxy thermosetting adhesive resin that is excellent in water resistance and water resistance and has little shrinkage during curing.

  The water content of the sealing adhesive according to the present invention is preferably 300 ppm or less, more preferably 0.01 to 200 ppm, and most preferably 0.01 to 100 ppm.

  The moisture content referred to in the present invention may be measured by any method. For example, a volumetric moisture meter (Karl Fischer), an infrared moisture meter, a microwave transmission moisture meter, a heat-dry weight method, GC / MS, IR, DSC (Differential Scanning Calorimeter), TDS (Temperature Desorption Analysis) can be mentioned. Further, using a precision moisture meter AVM-3000 (Omnitech) or the like, moisture can be measured from a pressure increase caused by evaporation of moisture, and moisture content of a film or a solid film can be measured.

  In the present invention, the moisture content of the sealing adhesive can be adjusted by, for example, placing it in a nitrogen atmosphere with a dew point temperature of −80 ° C. or lower and an oxygen concentration of 0.8 ppm, and changing the time. Further, it can be dried in a vacuum state of 100 Pa or less while changing the time. Further, the sealing adhesive can be dried only with an adhesive, but can also be placed in advance on the sealing member and dried.

  When close sealing (solid sealing) is performed, as the sealing member, for example, a 50 μm thick PET (polyethylene terephthalate) laminated with an aluminum foil (30 μm thick) is used. Using this as a sealing member, it is uniformly applied to the aluminum surface using a dispenser, a sealing adhesive is placed in advance, the resin substrate 1 and the sealing member 5 are aligned, and then both are crimped ( 0.1-3 MPa) and a temperature of 80-180 ° C. for tight adhesion / bonding (adhesion) for tight sealing (solid sealing).

  The heating or pressure bonding time varies depending on the type, amount, and area of the adhesive, but temporary bonding is performed at a pressure of 0.1 to 3 MPa, and the thermosetting time is within a range of 5 seconds to 10 minutes at a temperature of 80 to 180 ° C. Just choose.

  The use of a heated crimping roll is preferred because it allows simultaneous crimping (temporary bonding) and heating, and eliminates internal voids at the same time.

  In addition, as a method for forming the adhesive layer, a coating method such as roll coating, spin coating, screen printing, spray coating, or the like can be used using a dispenser depending on the material.

  As described above, solid sealing is a form in which there is no space between the sealing member and the organic EL element substrate and the resin is covered with a cured resin.

  Examples of the sealing member include metals such as stainless steel, aluminum, and magnesium alloys, polyethylene terephthalate, polycarbonate, polystyrene, nylon, plastics such as polyvinyl chloride, and composites thereof, glass, and the like. In the case of a resin film, a laminate of gas barrier layers such as aluminum, aluminum oxide, silicon oxide, and silicon nitride can be used in the same manner as the resin substrate.

The gas barrier layer can be formed by sputtering, vapor deposition or the like on both surfaces or one surface of the sealing member before molding the sealing member, or can be formed on both surfaces or one surface of the sealing member by the same method after sealing. Good. Also in this case, the oxygen permeability is 1 × 10 ⁻³ ml / (m ² · 24 h · atm) or less, and the water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) is 1 ×. It is preferably 10 ⁻³ g / (m ² · 24 h) or less.

  The sealing member may be a film laminated with a metal foil such as aluminum. As a method for laminating the polymer film on one side of the metal foil, a generally used laminating machine can be used. As the adhesive, polyurethane-based, polyester-based, epoxy-based, acrylic-based adhesives and the like can be used. You may use a hardening | curing agent together as needed. A hot melt lamination method, an extrusion lamination method and a coextrusion lamination method can also be used, but a dry lamination method is preferred.

  In addition, when the metal foil is formed by sputtering or vapor deposition and is formed from a fluid electrode material such as a conductive paste, it may be produced by a method of forming a metal foil on a polymer film as a base material. Good.

(9. Protective film, protective plate)
In order to increase the mechanical strength of the organic EL element, a protective film or a protective plate may be provided on the outer side of the sealing film or the sealing film on the side facing the support substrate with the functional layer interposed therebetween. In particular, when sealing is performed with a 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, etc. used for the sealing can be used, but the polymer film is light and thin. Is preferably used.

  In the present invention, it is preferable to have a light extraction member between the flexible support substrate and the anode or at any location on the light emission side from the flexible support substrate.

  Examples of the light extraction member include a prism sheet, a lens sheet, and a diffusion sheet. Moreover, the diffraction grating introduce | transduced in the interface which raise | generates total reflection, or any medium, a diffusion structure, etc. are mentioned.

  Usually, in an organic EL element that emits light from a substrate, a problem arises in that part of the light emitted from the light emitting layer undergoes total reflection at the interface between the substrate and air, resulting in loss of light. In order to solve this problem, the prism surface, lens-like processing is applied to the surface of the substrate, or the prism sheet, the lens sheet and the diffusion sheet are attached to the surface of the substrate, thereby suppressing the total reflection and the light extraction efficiency. To improve.

  In order to increase the light extraction efficiency, a method of introducing a diffraction grating or a method of introducing a diffusion structure in an interface or any medium that causes total reflection is known.

<< Method for Manufacturing Organic EL Element >>
As an example of the method for producing an organic EL device of the present invention, a method for producing an organic EL device comprising an anode / functional layer A / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode is used. explain.

  First, a desired electrode material, for example, a thin film made of an anode material is formed on a suitable substrate by a thin film forming method such as vapor deposition or sputtering so as to have a layer thickness of 1 μm or less, preferably 10 to 200 nm, An anode is produced.

  Next, a dispersion of metal oxide particles is applied thereon by spin coating to form functional layer A composed of metal oxide particles so that the layer thickness after drying is 5 to 40 nm.

  Next, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and a functional layer (organic compound thin film) of the electron injection layer, which are organic EL element materials, are formed thereon.

  The processing steps in the case of forming a functional layer by a coating method mainly include (i) a step of applying and laminating a coating liquid constituting the functional layer on the anode of the support substrate, and (ii) after coating and laminating. And a step of drying the coating liquid.

  The light emitting layer forming method (coating film forming method) is as described above.

  In the step (i), as a method for forming each layer, as described above, a vapor deposition method, a wet process (for example, spin coating method, casting method, die coating method, blade coating method, roll coating method, ink jet method, printing method, spray coating). Method, curtain coating method, LB method (Langmuir Brodgett method and the like can be used), and at least the light emitting layer of the present invention is preferably formed by a wet process.

  In the formation of functional layers other than the light emitting layer, a wet process is preferred in the present invention from the viewpoint that a homogeneous film is easily obtained and pinholes are difficult to be generated. Among them, a spin coating method, a casting method, a die coating are preferred. Film formation by a coating method such as a method, a blade coating method, a roll coating method or an ink jet method is preferred.

  Examples of the liquid medium for dissolving or dispersing the organic EL material according to the present invention include ketones such as methyl ethyl ketone and cyclohexanone, fatty acid esters such as ethyl acetate, halogenated hydrocarbons such as dichlorobenzene, toluene, xylene, and mesitylene. Aromatic hydrocarbons such as cyclohexylbenzene, aliphatic hydrocarbons such as cyclohexane, decalin, and dodecane, and organic solvents such as dimethylformamide (DMF) and dimethylsulfoxide (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.

  In addition, the preparation step for dissolving or dispersing the organic EL material according to the present invention and the application step until the organic EL material is applied on the substrate are preferably in an inert gas atmosphere. Since the film can be formed without degrading the performance of the organic EL element even if it is not carried out in step 1, it may not necessarily be carried out in an inert gas atmosphere. In this case, the manufacturing cost can be suppressed, which is more preferable.

  In the step (ii), the coated / laminated functional layer is dried.

  The term “drying” as used herein refers to a reduction to 0.2% or less when the solvent content of the film immediately after coating is 100%.

  As a means for drying, those generally used can be used, and examples thereof include reduced pressure or pressure drying, heat drying, air drying, IR drying, and electromagnetic wave drying. Among these, heat drying is preferable, and the temperature is equal to or higher than the boiling point of the solvent having the lowest boiling point in the functional layer coating solvent, and is maintained at a temperature lower than (Tg + 20) ° C. of the material having the lowest Tg among the Tg of the functional layer material. Most preferably. In the present invention, more specifically, it is preferable to hold and dry at 80 ° C. or higher and 150 ° C. or lower, and more preferable to hold and dry at 100 ° C. or higher and 130 ° C. or lower.

  The atmosphere when drying the coating liquid after coating / lamination is preferably an atmosphere having a volume concentration of a gas other than the inert gas of 200 ppm or less, but it is not necessarily in an inert gas atmosphere as in the liquid preparation coating process. It may not be necessary. In this case, the manufacturing cost can be suppressed, which is more preferable.

  The inert gas is preferably a rare gas such as nitrogen gas and argon gas, and most preferably nitrogen gas in terms of production cost.

  The coating / laminating and drying steps of these layers may be single wafer manufacturing or line manufacturing. Further, the drying process may be performed while being conveyed on the line, but from the viewpoint of productivity, it may be deposited or rolled in a non-contact manner in a roll form.

  After these layers are dried, a thin film made of a cathode material is formed thereon by a method such as vapor deposition or sputtering so as to have a layer thickness of 1 μm or less, preferably in the range of 50 nm to 200 nm. By providing, a desired organic EL element can be obtained.

  After the heat treatment, the organic EL element can be produced by adhering the close-sealing or sealing member to the electrode and the support substrate with an adhesive.

<Application>
The organic EL element of the present invention can be used as a display device such as a display device or a display, or various light emission sources (illumination devices).

  Examples of light sources include home lighting, interior lighting, clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, and light sources for optical sensors. Furthermore, it can be used in a wide range of applications such as general household appliances that require a display device, but it can be used effectively as a backlight for a liquid crystal display device combined with a color filter, and as a light source for illumination. it can.

  In the organic EL element of the present invention, patterning may be performed by a metal mask, an ink jet printing method, or the like as needed during film formation. 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 device may be patterned. Can do.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

<< Example of metal oxide particle preparation >>
(Metal oxide particles 1; for the present invention)
(Synthesis of molybdenum oxide particles by spray burner method)
Molybdenum 2-ethylhexanoate solution (15% by mass; solvent: xylene) was diluted with 25 g of xylene to obtain a molybdenum oxide precursor having a viscosity suitable for spraying. By spraying 30 ml of the obtained molybdenum oxide precursor into a flame having an oxygen concentration of 100 ppm, powder of metal oxide particles 1 was obtained.

  As process conditions, the flow rate of the molybdenum oxide precursor is 7 ml / min, the jet gas of the burner is oxygen and methane, the temperature of the flame is controlled to 1800 ° C. by adjusting the supply amount of both gases, The oxygen concentration was controlled at 100 ppm. According to XRD (X-ray diffraction) analysis of the metal oxide particles 1, formation of molybdenum oxide (IV) was confirmed. The powder had a deep blue color.

(Metal oxide particles 2; for the present invention)
(Synthesis of tungsten oxide particles by spray burner method)
50 g of 2-ethylhexanoic acid tungsten solution (15% by mass; solvent: xylene) was diluted with 30 g of xylene to obtain a tungsten oxide precursor having a viscosity suitable for spraying. By spraying 30 ml of the obtained tungsten oxide precursor into a flame having an oxygen concentration of 100 ppm, a powder of metal oxide particles 2 was obtained.

As the process conditions, the flow rate of the tungsten oxide precursor is 10 ml / min, and the temperature of the flame is controlled to 1800 ° C. by adjusting the supply amounts of both gases with oxygen and methane, and the oxygen concentration of the flame Was controlled to 100 ppm. According to the XRD analysis of the metal oxide particles 2, formation of WO ₃ (tungsten oxide (VI)) was confirmed. The powder had a dark green color.

(Metal oxide particles 3; for comparative examples)
(Synthesis of tungsten oxide particles with dispersing agent)
In a 50 ml three-necked flask, 1 g of n-hexadecylamine (dispersing agent) and 27 g of n-octyl ether are weighed, depressurized while stirring, and 1 hour at room temperature (24 ° C.) to remove low volatile components. I left it alone. The pressure was changed from the reduced pressure to the atmosphere, and 1 g of tungsten hexacarbonyl was added. The mixture was heated to 270 ° C. with stirring under an argon gas atmosphere, and the temperature was maintained for 1 hour. Then, after cooling this liquid mixture to room temperature (24 degreeC) and changing from argon gas atmosphere to air | atmosphere, ethanol 40g was dripped. Subsequently, after separating the precipitate from the reaction solution by centrifugation, purification by reprecipitation was performed according to the procedure shown below.

This precipitate was mixed with 13 g of chloroform to obtain a dispersion, and 13 g of ethanol was added dropwise to the dispersion to obtain a reprecipitation liquid having a purified precipitate. The precipitate is centrifuged, the reaction solution is separated, and the solid content is dried to obtain a metal oxide which is a purified product of WO ₃ (tungsten (VI))-containing particles protected with n-hexadecylamine. Product particles 3 were obtained.

(Metal oxide particles 4; for comparative examples)
(Synthesis of tungsten oxide particle slurry)
In a shaker, 0.3 g of WO ₃ powder (average particle size: 13.0 to 18.0 μm) is mixed with 30 ml of toluene solvent and zirconia beads having a diameter of 2 mm, and dispersed in the solvent while physically pulverizing. ₃ of toluene dispersion was obtained. Next, the dispersion is dispersed with zirconia beads having a diameter of 0.3 mm for 24 hours. The supernatant dispersion is filtered through a 0.2 μm filter to remove dust, and centrifuged to collect a precipitate. A slurry of 4 was obtained.

<Measurement of particle size of metal oxide particles>
Metal oxide particles 1 were dispersed in ethanol at a concentration of 0.4% by mass to obtain a dispersion of Synthesis Example 1. Next, an X-ray diffractometer (RINT-TTRII, manufactured by Rigaku Corporation) was used to measure a small angle scattering profile of the dispersion, and a numerical value was measured using NANO-Solver (manufactured by Rigaku Corporation) which is a particle diameter / hole diameter analysis software. Average particle size and maximum particle size were determined. The number average particle diameter of the metal oxide particles 2 to 4 was also evaluated under the same conditions. The evaluation results are shown in Table 1.

<Determination of self-dispersibility of metal oxide particles>
The metal oxide particles can be dispersed in ethanol at a concentration of 0.6% by mass without using a dispersant or covering the surface of the metal oxide particles with an organic compound, and a good dispersion state can be maintained for a certain period of time. If it is drunk, it is determined to have “self-dispersibility”.

  Specifically, when the dispersion liquid dispersed until the number average particle diameter falls within the range of 5 to 20 nm is left to stand at 25 ° C. for one week in a closed container, self-dispersibility if no precipitation is observed by visual observation. Was determined to be “present”, and if precipitation was observed, the self-dispersibility was determined to be “not present”. In addition, since the metal oxide particle 3 was already protected with n-hexadecylamine, that is, covered with an organic compound, the self-dispersibility was determined to be “none”. Table 1 shows the determination results.

[Example 1]
(1) Production of sample A (organic EL element of the present invention) (1.1) Production of gas barrier flexible film (flexible support substrate) Polyethylene naphthalate film (Teijin DuPont) as a flexible film A film-forming film (hereinafter abbreviated as PEN) is formed on the entire surface on the side where the first electrode is formed using an atmospheric pressure plasma discharge treatment apparatus having the structure described in Japanese Patent Application Laid-Open No. 2004-68143. An inorganic gas barrier layer made of SiOx is formed on the film so as to have a thickness of 500 nm, an oxygen permeability of 0.001 ml / (m ² · 24 h · atm) or less, and a water vapor permeability of 0.001 g / (m ² 24h) The following gas barrier flexible film (flexible support substrate) was produced.

(1.2) Formation of anode On the surface opposite to the gas barrier layer of the prepared gas barrier flexible film, ITO (indium tin oxide) with a thickness of 120 nm was formed by sputtering, and then by photolithography. Patterning was performed to form an anode. The pattern was such that the light emission area was 50 mm square. The patterned ITO substrate was subjected to ultrasonic cleaning with isopropyl alcohol, dried with dry nitrogen gas, and UV ozone cleaning was performed for 5 minutes.

(1.3) Formation of Hole Injection Layer I The gas barrier flexible film on which this anode was formed was transferred to a nitrogen atmosphere using nitrogen gas (grade G1). The metal oxide particles 1 (molybdenum oxide particles) were dispersed in ethanol at a concentration of 0.4% by mass to prepare a dispersion A for forming a hole injection layer. Subsequently, the dispersion A for forming the hole injection layer is applied onto the cleaned anode by a spin coating method, and after application, the dispersion is formed at 30 ° C. in the atmosphere at 100 ° C. using a hot plate to evaporate the solvent. A hole injection layer I made of molybdenum oxide particles was formed by partial drying. The dried thickness of the hole injection layer I after drying was 10 nm.

  Moreover, as a result of producing a single layer film on the glass substrate with the dispersion A for forming the hole injection layer and evaluating the film composition using X-ray photoelectron spectroscopy (XPS), only the peak of molybdenum oxide was detected. Even when this dispersion for forming a hole injection layer was allowed to stand at room temperature for 1 week in a sealed container, no precipitate was confirmed by visual observation. The reason why the dispersion stability is high in this way is presumed that the surfaces of the molybdenum oxide particles are modified with OH groups, and it is considered that the dispersibility is improved by the OH groups.

(1.4) Formation of hole transport layer In the gas barrier flexible film formed up to the hole injection layer, exemplified compound (60) (Mw = 80,000) of the hole transport material is changed to chlorobenzene. A solution dissolved at a concentration of 0.5% by mass was formed by spin coating at 1500 rpm for 30 seconds, and then kept at 160 ° C. for 30 minutes to form a hole transport layer having a layer thickness of 30 nm.

(1.5) Formation of Light-Emitting Layer Next, on the hole transport layer, a light-emitting layer composition having the following composition was used, and a thin film was formed by spin coating under conditions of 1500 rpm and 30 seconds. A light emitting layer having a layer thickness of 50 nm was formed by holding for 5 minutes.

<Light emitting layer composition>
Host compound 29 8.78 parts by mass Phosphorescence emission dopant DP-1 3.01 parts by mass Phosphorescence emission dopant D-67 0.05 parts by mass Phosphorescence emission dopant D-75 0.05 parts by mass Isopropyl acetate 2000 parts by mass ( 1.6) Formation of Electron Transport Layer Subsequently, a solution of 20 mg of the following compound A (a compound represented by the general formula (A)) dissolved in 4 ml of tetrafluoropropanol (TFPO) is formed on the light emitting layer. A film was formed by spin coating at 1500 rpm for 30 seconds, and then dried and held at 120 ° C. for 30 minutes to provide an electron transport layer having a layer thickness of 30 nm.

（１．７）電子注入層、陰極の形成
続いて、上記電子輸送層まで設けた可撓性支持基板を大気に曝露することなく真空蒸着装置へ取り付けた。なお、真空蒸着装置には、フッ化ナトリウムが入ったモリブデン製抵抗加熱ボート、フッ化カリウムが入ったモリブデン製抵抗加熱ボート及びアルミニウムが入ったモリブデン製抵抗加熱ボートが、あらかじめ取り付けられている。真空蒸着装置の真空槽を４×１０^−５Ｐａまで減圧した後、前記ボートに通電して加熱してフッ化ナトリウムを０．０２ｎｍ／秒で蒸着して前記電子輸送層上に層厚１ｎｍの薄膜を形成し、続けて同様にフッ化カリウムを０．０２ｎｍ／秒で蒸着してフッ化ナトリウム上に層厚０．５ｎｍの薄膜を形成し、フッ化ナトリウムの薄膜とフッ化カリウムの薄膜からなる層厚１．５ｎｍの電子注入層を形成した。

(1.7) Formation of Electron Injection Layer and Cathode Subsequently, the flexible support substrate provided up to the electron transport layer was attached to a vacuum deposition apparatus without being exposed to the atmosphere. Note that a molybdenum resistance heating boat containing sodium fluoride, a molybdenum resistance heating boat containing potassium fluoride, and a molybdenum resistance heating boat containing aluminum are attached to the vacuum deposition apparatus in advance. After reducing the vacuum chamber of the vacuum deposition apparatus to 4 × 10 ⁻⁵ Pa, the boat was energized and heated to deposit sodium fluoride at 0.02 nm / second, and a layer thickness of 1 nm was formed on the electron transport layer. A thin film is formed, and subsequently, potassium fluoride is similarly deposited at 0.02 nm / second to form a thin film with a thickness of 0.5 nm on sodium fluoride. An electron injection layer having a layer thickness of 1.5 nm was formed.

Subsequently, aluminum was deposited to form a cathode having a thickness of 100 nm.
(1.8) Sealing and production of organic EL element Subsequently, a flexible sealing member in which the following sealing adhesive was laminated on the cathode surface of the substrate provided up to the cathode was used using a commercially available roller laminating apparatus. A sample A (organic EL element) was manufactured by closely sealing at a heating / compression roller temperature of 120 ° C., a pressure of 0.5 MPa, and an apparatus speed of 0.3 m / min.

(Flexible sealing member)
Specifically, as a flexible sealing member, a 30 μm thick aluminum foil (manufactured by Toyo Aluminum Co., Ltd.), a polyethylene terephthalate (PET) film (12 μm thickness) and an adhesive for dry lamination (two-component reactive urethane) (Adhesive layer thickness of 1.5 μm) was used.

(Lamination of sealing adhesive)
A thermosetting adhesive was applied as a sealing adhesive to the aluminum surface of the film with a thickness of 20 μm using a dispenser. In order to remove moisture in the sealing adhesive, it was dried under vacuum of 100 Pa or less for 12 hours. Furthermore, it moved to nitrogen atmosphere with a dew point temperature of −80 ° C. or lower and an oxygen concentration of 0.8 ppm, dried for 12 hours or longer, and adjusted the moisture content of the sealing adhesive to 100 ppm or lower.

  As the thermosetting adhesive, an epoxy adhesive mixed with the following (A) to (C) was used.

(A) Bisphenol A diglycidyl ether (DGEBA) 10.1 parts by mass (B) Dicyandiamide (DICY) 8.5 parts by mass (C) Epoxy adduct-based curing accelerator 4.7 parts by mass As described above, FIG. The sample A (organic EL element) in which the flexible sealing member was closely attached and arranged so as to cover the joint between the extraction electrode and the electrode lead as in the form described in the above.

(2) Production of Sample B (Organic EL Device of the Present Invention) The metal oxide particles 2 (tungsten oxide particles) are dispersed in ethanol at a concentration of 0.5% by mass to form a hole injection layer. Liquid B was prepared.

  In the preparation of Sample A, hole injection layer I was formed in the same manner as Sample A except that hole injection layer formation dispersion B was used instead of hole injection layer formation dispersion A. Produced.

  On the other hand, as a result of producing a monolayer film on the glass substrate with the dispersion B for forming the hole injection layer and evaluating the film composition using X-ray photoelectron spectroscopy (XPS), only the peak of tungsten oxide was detected. . Moreover, the deposit B was not confirmed even if it visually observed after leaving the dispersion | distribution liquid B for hole injection layer formation for one week at room temperature in an airtight container. The surface of the tungsten oxide particles is presumed to be modified with OH groups, and it is considered that the dispersibility is improved by the OH groups.

(3) Production of Sample C (Comparative Organic EL Device) The metal oxide particles 3 (tungsten oxide particles) were dispersed in ethanol at a concentration of 0.6% by mass to form a hole injection layer forming dispersion. Liquid C was prepared.

  In the preparation of Sample A, the hole injection layer I was formed in the same manner as in Sample A except that the hole injection layer formation dispersion C was used instead of the hole injection layer formation dispersion A. Produced.

  On the other hand, as a result of producing a single layer film on a glass substrate with the dispersion C for forming the hole injection layer and evaluating the film composition using X-ray photoelectron spectroscopy (XPS), peaks of tungsten oxide, carbon and nitrogen were obtained. Was detected. Similar results were obtained even under conditions of drying at 200 ° C. for 30 minutes in the atmosphere. The peaks of carbon and nitrogen are presumed to be derived from the remaining n-hexadecylamine (dispersant).

  Moreover, even if this hole injection layer forming dispersion C was allowed to stand at room temperature for 1 week in a sealed container and then visually observed, no precipitate was confirmed.

(4) Production of Sample D (Comparative Example Organic EL Device) The metal oxide particles 4 (tungsten oxide particles) were dispersed in ethanol at a concentration of 0.6% by mass to form a hole injection layer forming dispersion. Liquid D was prepared.

  In the preparation of the sample A, the hole injection layer I was formed in the same manner except that the hole injection layer formation dispersion D was used instead of the hole injection layer formation dispersion A. Produced.

  On the other hand, as a result of producing a single layer film on a glass substrate with the dispersion D for forming the hole injection layer and evaluating the film composition using X-ray photoelectron spectroscopy (XPS), a peak of tungsten oxide was detected. . As a result of visually observing this dispersion D for forming the hole injection layer D in a sealed container at room temperature for one week, aggregates were precipitated.

(5) Production of Sample E (Comparative Example Organic EL Device) Sample E was produced in the same manner as in production of Sample A, except that hole injection layer I was not provided.

<< Evaluation of organic EL elements >>
About said sample AE, each evaluation of following (1)-(3) was performed.

(1) Measurement of light emission luminance and driving voltage Light emission of each sample when a constant current is applied to each sample using a spectral radiance meter CS-2000 (manufactured by Konica Minolta Optics) in a 24 ° C environment. Luminance and drive voltage were determined. Table 2 shows the obtained results. In Table 2, the light emission luminance and drive voltage of Sample E (Comparative Example) are set to “100”, and the light emission luminance and drive voltage of Samples A to D are shown as relative values.

(2) Evaluation of luminance unevenness The element which emitted light with the drive voltage was observed with a microscope or visually to evaluate whether there was any luminance unevenness. In Table 2, “◎” indicates no luminance unevenness, “○” indicates that there is no luminance unevenness in the microscope observation, but there is no luminance unevenness in the visual observation, and “△” indicates that the luminance unevenness is slightly confirmed visually. Indicates that there is no problem, and “x” indicates that the luminance unevenness is remarkable and is a problem.

(3) Evaluation of continuous drive stability (lifetime) The samples A to E are bent along a cylinder with a radius of 5 cm so that the flexible sealing member is on the inside, and continuously driven in that state, and the above spectroscopy The luminance of the bent portion was measured using a radiance meter CS-2000, and the time (LT50) during which the measured luminance was reduced by half was determined. The driving condition was set to a current value of 4000 cd / m ² at the start of continuous driving.

  A relative value with the LT50 of Sample E (Comparative Example) as “100” was determined, and this was used as a measure of continuous drive stability. The evaluation results are shown in Table 2. In Table 2, it shows that it is excellent in continuous drive stability (long life), so that a numerical value is large.

(4) Comprehensive evaluation Comprehensive performance was determined based on evaluation of said (1), (2) and (3). In Table 2, “◎” indicates very good, “◯” indicates excellent, “Δ” indicates slightly superior, and “×” indicates inferior.

  As shown in Table 2, from the comparison between the samples A and B of the present invention and the samples C to D of the comparative examples, the samples A and B of the present invention showed good results in each evaluation, and the sample B was particularly good. . Among the present inventions, tungsten oxide is presumed to be advantageous for forming a charge transfer complex with the hole transport layer. In the sample C of the comparative example, since the dispersant remains as described above, it is presumed that the light emission lifetime is inferior to the samples A and B. In the sample D of the comparative example, it is presumed that the device stability is low because the dispersibility is not excellent and a large particle size is mixed.

  From the above, it can be seen that it is important for the hole injection layer to contain self-dispersing metal oxide particles in order to improve the performance of luminous efficiency, luminous lifetime and luminance unevenness.

[Example 2]
(1) Preparation of Sample 1 (Organic EL Device of the Present Invention) In preparation of Sample A of Example 1, the hole injection layer I was replaced with a hole injection layer formed as follows, Sample 1 was prepared.

(Hole injection layer)
In a nitrogen atmosphere using nitrogen gas (grade G1), poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (abbreviated as PEDOT / PSS, manufactured by Bayer, Baytron P Al 4083) to 70% with ethanol A diluted ethanol solution was prepared. Subsequently, metal oxide particles 1 (molybdenum oxide particles) were dispersed in the ethanol solution at a concentration of 0.4% by mass to prepare a coating solution that is a metal oxide particle-containing composition.

On the anode of the cleaned gas barrier flexible film formed up to the anode, the above coating solution was formed by spin coating at 3000 rpm for 30 seconds, and then dried at 100 ° C. for 1 hour to obtain a layer thickness. A 30 nm hole injection layer was provided.
(2) Preparation of Sample 2 (Organic EL Device of the Present Invention) In the preparation of Sample 1, the metal oxide particles 1 (molybdenum oxide particles) were used as the metal oxide particles 2 prepared in Synthesis Example 2. Sample 2 was produced in the same manner except that it was changed to (tungsten oxide particles).
(3) Preparation of Sample 3 (Comparative Example Organic EL Device) In the preparation of Sample 1, the metal oxide particles 1 (molybdenum oxide particles) were replaced with the metal oxide particles 3 prepared in Synthesis Example 3. Sample 3 was produced in the same manner except that it was changed to (tungsten oxide particles).
(4) Preparation of Sample 4 (Organic EL Device of Comparative Example) In preparation of Sample 1, the metal oxide particles 1 (molybdenum oxide particles) were used as the metal oxide particles 4 prepared in Synthesis Example 4. Sample 4 was produced in the same manner except that it was changed to (tungsten oxide particles).
(5) Production of Sample 5 (Organic EL Device of Comparative Example) Sample 5 was produced in the same manner as in production of Sample 1, except that the metal oxide particles 1 were not added and a hole injection layer was formed.

  Samples 1 to 5 (organic EL elements) produced as described above were evaluated in the same manner as in [Example 1], and the results are shown in Table 3. In Table 3, the light emission luminance, drive voltage, and light emission lifetime of each sample were expressed as relative values with Sample 5 (Comparative Example) as “100”. The luminance unevenness and comprehensive evaluation were determined based on the same evaluation criteria as in [Example 1], and are shown in Table 3.

  As shown in Table 3, from the comparison between Samples 1 and 2 (present invention) and Samples 3 to 5, Samples 1 and 2 showed good results in each evaluation, and Sample 2 was particularly good. Tungsten oxide is presumed to be advantageous for forming a charge transfer complex with the hole injection layer. Since the sample 3 of the comparative example has a dispersant as described above, it is presumed that the emission lifetime was not superior to those of the samples 1 and 2. In the sample 4 of the comparative example, the device stability is estimated to be low because the dispersibility is not excellent and a large particle size is mixed.

  From the above, in order to improve the luminous efficiency and the luminous lifetime, it is important that the metal oxide particles have a number average particle diameter of 20 nm or less and a uniform particle diameter, and do not contain a dispersant. .

  From the above, it can be seen that it is important for the hole injection layer to contain self-dispersing metal oxide particles in order to improve the performance of luminous efficiency, luminous lifetime and luminance unevenness.

Example 3
(1) Preparation of Sample I (Organic EL Device of the Present Invention) In the preparation of Sample A of Example 1, poly (3,4-ethylene was formed after the formation of the hole injection layer I and before the formation of the hole transport layer. Dioxythiophene) -polystyrene sulfonate (abbreviated as PEDOT / PSS, manufactured by Bayer, Baytron P Al 4083) diluted to 70% with ethanol was formed into a film by spin coating at 3000 rpm for 30 seconds, and then at 100 ° C. Sample I was produced in the same manner except that it was dried for 1 hour and provided with a hole injection layer II having a layer thickness of 30 nm.

(2) Preparation of Sample II (Organic EL Device of the Present Invention) In preparation of Sample B of Example 1, poly (3,4-ethylene was formed after the formation of the hole injection layer I and before the formation of the hole transport layer. Dioxythiophene) -polystyrene sulfonate (abbreviated as PEDOT / PSS, manufactured by Bayer, Baytron P Al 4083) diluted to 70% with ethanol was formed into a film by spin coating at 3000 rpm for 30 seconds, and then at 100 ° C. Sample II was prepared in the same manner except that it was dried for 1 hour and provided with a hole injection layer II having a layer thickness of 30 nm.

(3) Preparation of Sample III (Comparative Example Organic EL Device) In preparation of Sample C of Example 1, poly (3,4-ethylene was formed after formation of the hole injection layer I and before formation of the hole transport layer. Dioxythiophene) -polystyrene sulfonate (abbreviated as PEDOT / PSS, manufactured by Bayer, Baytron P Al 4083) diluted to 70% with ethanol was formed into a film by spin coating at 3000 rpm for 30 seconds, and then at 100 ° C. Sample III was prepared in the same manner except that it was dried for 1 hour and provided with a hole injection layer II having a thickness of 30 nm.

(4) Preparation of Sample IV (Organic EL Device of Comparative Example) In preparation of Sample D of Example 1, poly (3,4-ethylene was formed after formation of the hole injection layer I and before formation of the hole transport layer. Dioxythiophene) -polystyrene sulfonate (abbreviated as PEDOT / PSS, manufactured by Bayer, Baytron P Al 4083) diluted to 70% with ethanol was formed into a film by spin coating at 3000 rpm for 30 seconds, and then at 100 ° C. Sample IV was prepared in the same manner except that the hole injection layer II having a layer thickness of 30 nm was provided after drying for 1 hour.

(5) Preparation of Sample V (Comparative Example Organic EL Device) In the preparation of Sample A of Example 1, the hole injection layer I was not formed, and the poly (3,4- Ethylenedioxythiophene) -polystyrene sulfonate (abbreviated as PEDOT / PSS, manufactured by Bayer, Baytron P Al 4083) diluted to 70% with ethanol was formed into a film by spin coating at 3000 rpm for 30 seconds and then heated to 100 ° C. The sample V was prepared in the same manner except that the hole injection layer II having a layer thickness of 30 nm was provided.
<< Evaluation of organic EL elements >>
Samples I to V (organic EL elements) produced as described above were evaluated in the same manner as in [Example 1], and the results are shown in Table 4. In Table 4, the light emission luminance, drive voltage, and light emission lifetime of each sample are expressed as relative values with Sample V (Comparative Example) as “100”. The luminance unevenness and comprehensive evaluation were determined according to the same evaluation criteria as in [Example 1] and are shown in Table 4.

  As shown in Table 4, from the comparison between Samples I and II of the present invention and Samples III to V of Comparative Examples, Samples I and II of the present invention showed good results in each evaluation, and Sample II was particularly good. . Among the present invention, tungsten oxide is presumed to be more advantageous for forming a charge transfer complex with a hole injection layer than molybdenum oxide. In the sample III of the comparative example, it is presumed that the light emission lifetime was not superior to those of Examples I and II due to the residual dispersant as described above. In Comparative Example V, since the functional layer A is not provided between the anode and the hole injection layer containing an acidic substance, it is estimated that the element stability is low.

  In addition, by forming a metal oxide particle layer at the interface between the anode and the PEDOT / PSS layer, corrosion of the anode due to an acidic substance contained in the PEDOT / PSS layer can be prevented, and a further increase in life has been achieved. .

  From the above, it can be seen that it is important for the hole injection layer to contain self-dispersing metal oxide particles in order to improve the performance of luminous efficiency, luminous lifetime and luminance unevenness. Further, by forming the metal oxide particle layer at the interface of the hole injection layer containing the anodic acidic substance, corrosion of the acidic substance can be prevented, leading to a longer life.

DESCRIPTION OF SYMBOLS 1 Flexible support substrate 2 Anode 3 Hole injection layer 4 Hole transport layer 5 Light emitting layer 6 Electron transport layer 7 Electron injection layer 8 Cathode 9 Sealing adhesive 10 Flexible sealing member 20 Functional layer 100 Organic EL element

Claims (12)

  An organic electroluminescence device having at least one functional layer A and a light emitting layer between an anode and a cathode, wherein the functional layer A contains self-dispersing metal oxide particles. Luminescence element.   2. The organic electroluminescence device according to claim 1, wherein at least one of the metal elements constituting the metal oxide particles is a metal element selected from Group 1 to Group 13 of the periodic table.   The organic electroluminescence device according to claim 2, wherein the metal element is molybdenum or tungsten.   The number average particle diameter of the said metal oxide particle exists in the range of 5-100 nm, The organic electroluminescent element as described in any one of Claim 1- Claim 3 characterized by the above-mentioned.   The number average particle diameter of the said metal oxide particle exists in the range of 5-20 nm, The organic electroluminescent element as described in any one of Claim 1- Claim 3 characterized by the above-mentioned.   The organic electroluminescent element according to claim 1, wherein the functional layer A is provided between the anode and the light emitting layer.   The organic electroluminescence device according to any one of claims 1 to 5, wherein a hole transport layer is provided between the functional layer A and the light emitting layer.   The organic electroluminescent element according to claim 1, wherein a hole injection layer is provided between the functional layer A and the light emitting layer.   The organic electroluminescence device according to claim 8, wherein the hole injection layer contains an acidic substance as a dopant.   The organic electroluminescence device according to claim 8, wherein the hole injection layer contains a polythiophene derivative and an acidic substance as a dopant.   It is a metal oxide particle containing composition which forms the said functional layer A which the organic electroluminescent element as described in any one of Claims 1-10 has, Comprising: Self-dispersible metal oxide particle | grains are the following. A composition containing metal oxide particles, which is dispersed in a medium containing a solvent.   It is a manufacturing method of the organic electroluminescent element which manufactures the organic electroluminescent element as described in any one of Claim 1- Claim 10, Comprising: The said functional layer A is formed by a wet process, The organic characterized by the above-mentioned. Manufacturing method of electroluminescent element.

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