JP2008135198A - Manufacturing method of organic electroluminescent element, organic electroluminescent element, display device, and lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an organic EL element showing high luminescent efficiency and long life, an organic EL element, a lighting device, and a display device. <P>SOLUTION: The manufacturing method of the organic electroluminescent element provided with at least an anode and a cathode on a support substrate as well as an organic layer containing at least one luminescent layer between the anode and the cathode includes a process of forming at least one organic layer with the use of an organic electroluminescent element material precursor. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

  Conventionally, there is an electroluminescence display (ELD) as a light-emitting electronic display device. Examples of the constituent elements of ELD include inorganic electroluminescent elements and organic electroluminescent elements (hereinafter also referred to as organic EL elements).

  Inorganic electroluminescent elements have been used as planar light sources, but an alternating high voltage is required to drive the light emitting elements.

  On the other hand, an organic EL element has a configuration in which a light emitting layer containing a compound that emits light is sandwiched between a cathode and an anode, and injects electrons and holes into the light emitting layer to recombine excitons. This is an element that emits light by utilizing the emission of light (fluorescence / phosphorescence) when the exciton (exciton) is deactivated, and can emit light at a voltage of several volts to several tens of volts. Since it is a self-luminous type, it has a wide viewing angle, high visibility, and since it is a thin-film type complete solid-state device, it has attracted attention from the viewpoints of space saving and portability.

  For the development of organic EL elements for practical use in the future, organic EL elements that emit light efficiently and with high luminance with lower power consumption are desired.

  For example, Japanese Patent No. 3093796 discloses a technique for doping a stilbene derivative, a distyrylarylene derivative or a tristyrylarylene derivative with a small amount of a phosphor to improve emission luminance and extend the lifetime of the device. Japanese Patent Laid-Open No. 63-264692 discloses an element having an organic light-emitting layer in which an 8-hydroxyquinoline aluminum complex is used as a host compound and a small amount of phosphor is doped therein. For example, an element having an organic light emitting layer in which an 8-hydroxyquinoline aluminum complex is used as a host compound and doped with a quinacridone dye is known.

  In the technique disclosed in the above-mentioned patent document, when the emission from the excited singlet is used, the generation ratio of the singlet exciton and the triplet exciton is 1: 3, so the generation probability of the luminescent excited species is 25%. Since the light extraction efficiency is about 20%, the limit of the external extraction quantum efficiency (ηext) is set to 5%.

  However, M.M. A. Baldo et al. , Nature, 395, 151-154 (1998), since Princeton University reported on an organic EL device using phosphorescence emission from an excited triplet. A. Baldo et al. , Nature, 403, 17, 750-753 (2000), and US Pat. No. 6,097,147, research on materials that exhibit phosphorescence at room temperature has become active.

  In addition, recently discovered organic EL devices that use phosphorescence can realize a luminous efficiency that is approximately four times that of previous devices that use fluorescence. Research and development of light-emitting element layer configurations and electrodes are performed all over the world. For example, S.M. Lamansky et al. , J .; Am. Chem. Soc. , 123, 4304 (2001), a number of compounds are being studied for synthesis centering on heavy metal complexes such as iridium complexes.

  In addition, the organic EL element is an all-solid element composed of an organic material film having a thickness of only about 0.1 μm between the electrodes, and the light emission can be achieved with a relatively low voltage of about 2V to 20V. Therefore, it is a technology that is expected as a next-generation flat display and illumination.

  Furthermore, the recently discovered organic EL using phosphorescence emission can realize a light emission efficiency of about 4 times in principle compared to that using previous fluorescence emission. Research and development of device layer configurations and electrodes are performed all over the world.

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

  In particular, in terms of cost, poor productivity is considered as a factor.

  Most of organic EL currently commercialized are manufactured by a so-called vapor deposition method in which a low molecular material is vapor deposited to form a film. In this vapor deposition method, an organic EL material can be used as a low-molecular compound that can be easily purified (a high-purity material can be easily obtained), and a laminated structure can be easily formed. Are better.

However, since vapor deposition is performed under a high vacuum condition of 10 ⁻⁴ Pa or less, restrictions are imposed on the film forming apparatus, and in practice it can be applied only to a substrate with a small area. In addition, there is a drawback in that it takes a long time and the throughput is low, and the size of the member that can be manufactured is limited, and at the same time, a process for taking in and out the member is necessary, which is not suitable for continuous production. .

  In particular, it is a problem when applied to lighting applications or large-area electronic displays, and organic EL is one of the causes that are not practically used for such applications.

  On the other hand, coating methods that produce organic compound layers by processes such as spin coating, ink jet, printing, and spraying are suitable for producing thin films at normal pressure and for producing uniform films over a large area. As one of means for enabling the above, a method using a solution containing an organic EL material has been proposed, and a low molecular material or a high molecular material can be used as the organic EL material.

  However, in application using a low molecular weight material, many of the organic materials used in the organic EL element are close to solvent solubility, and it is not possible to appropriately suppress mixing of the lower layer and the upper layer when forming a laminated film. It is difficult to obtain a high-performance EL element.

  For appropriately suppressing the mixing of the lower layer and the upper layer at the time of forming the laminated film, a method of laminating an organic compound using a solvent that is partially polar (see, for example, Patent Document 1) is known. However, because of the limited structure, there is a limit to desire high performance for individual materials.

  In order to achieve high luminous efficiency and long life at the same time, it is desirable to stack a plurality of functional layers. In order to stack a plurality of layers using the coating method, the lower layer must be insoluble in the upper coating solution, but for very thin films of the order of several tens of nm, a slightly soluble solvent is required. Even if it exists, the problem that a part of lower layer film | membrane melt | dissolves or an interface will be disturb | confused by a solvent arises.

  Such contamination to the upper layer of the lower layer material and disturbance of the interface cause a decrease in the light emission efficiency of the device and a deterioration in the device life, and therefore need to be improved. To solve these problems, for example, a polymer material is used. It has been proposed to use.

  However, in general, polymer materials are difficult to purify, and in particular, organic electroluminescence devices are difficult to apply because very few impurities can cause a significant decrease in the light emission lifetime of the device.

  For example, there is a technique of increasing the molecular weight after forming a constituent layer of an organic electroluminescence element, and a technique of adding a material having two or more vinyl groups to a plurality of layers is disclosed. A method of performing irradiation with ultraviolet rays or heat at the time of forming an organic layer before laminating (see, for example, Patent Document 2), a production method of causing a Diels-Alder reaction between two molecules in the same layer (for example, , See Patent Document 3).

All of the above techniques are methods for completing the polymerization reaction at the time of film formation or immediately after film formation (before attaching the cathode), but are still insufficient from the practical viewpoint of improving the durability of the organic EL device. Therefore, there is a demand for further technology for improving the durability of elements.
JP-A-11-251066 JP 2001-297882 A JP 2003-86371 A

  An object of the present invention is to provide an organic EL element manufacturing method, an organic EL element, an illumination device, and a display device that exhibit high luminous efficiency and have a long lifetime.

  The above object of the present invention has been achieved by the following constitution.

1. In a method for producing an organic electroluminescent device having at least an anode and a cathode on a support substrate, and having an organic layer including at least one light emitting layer between the anode and the cathode,
The manufacturing method of the organic electroluminescent element characterized by having the process of forming at least one layer of this organic layer using an organic electroluminescent element material precursor.

  2. Step of providing a precursor-containing layer by applying a solution or dispersion containing an organic electroluminescence element material precursor, and then converting the organic electroluminescence element material precursor in the precursor-containing layer into an organic electroluminescence element material 2. The method for producing an organic electroluminescent element according to 1 above, further comprising a step of forming at least one organic layer by performing a conversion process.

  3. The method 1 further comprises a step of forming an organic compound-containing layer on at least one organic layer containing the organic electroluminescence element material formed by converting the organic electroluminescence element material precursor. Or the manufacturing method of the organic electroluminescent element of 2.

  4). 4. The method for producing an organic electroluminescent element according to any one of 1 to 3, wherein the conversion treatment of the organic electroluminescent element material precursor includes an ultraviolet irradiation step.

  5. 4. The method for producing an organic electroluminescent element according to any one of 1 to 3, wherein the conversion treatment of the organic electroluminescent element material precursor includes a heat treatment step.

  6). The molecular weight A of the organic electroluminescence element material precursor in the precursor-containing layer and the molecular weight B of the organic electroluminescence element material formed by the conversion process of the precursor satisfy the following inequality (1). 6. The method for producing an organic electroluminescent element according to any one of 2 to 5, wherein:

Inequality (1)
Molecular weight A> Molecular weight B
7). An organic electroluminescence device manufactured by the method for manufacturing an organic electroluminescence device according to any one of 1 to 6 above.

  8). 8. The organic electroluminescence device as described in 7 above, wherein the organic electroluminescence device has a plurality of organic layers formed using the organic electroluminescence device material precursor.

  9. 9. The organic electroluminescence device according to 7 or 8, wherein at least one of the organic layers formed using the organic electroluminescence device material precursor is provided between a cathode layer and a light emitting layer. .

  10. 9. The organic electroluminescence device according to 7 or 8, wherein at least one of the organic layers formed using the organic electroluminescence device material precursor is provided between the anode layer and the light emitting layer. .

  11. 11. The organic electroluminescent element according to any one of 7 to 10 above, which has an organic layer containing a phosphorescent compound as a constituent layer.

  12 The organic electroluminescence device according to any one of 7 to 11, which emits white light.

  13. A display device comprising the organic electroluminescence element according to any one of 7 to 12 above.

  14 An illumination device comprising the organic electroluminescence element according to any one of 7 to 12 above.

  According to the present invention, it was possible to provide a method for manufacturing an organic EL element, an organic EL element, an illumination device, and a display device that exhibit high luminous efficiency and have a long lifetime.

  In the manufacturing method of the organic EL element material of the present invention, at least one of the constituent layers of the organic EL element using the organic EL element material precursor according to the configuration defined in any one of claims 1 to 5. Succeeded in forming an organic layer.

  Moreover, it turned out that the organic EL element manufactured using the manufacturing method of the organic EL element material of this invention shows high luminous efficiency, and a long luminescent lifetime. In addition, according to the present invention, an illumination device and a display device each including the organic EL element of the present invention can be provided.

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

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

  As a result of various investigations to appropriately suppress the mixing of the lower layer and the upper layer at the time of forming the above-mentioned problem, that is, the laminated film of the organic EL element constituent layer, the present inventors, when forming the constituent layer of the organic EL element, By applying the step of forming a layer using an organic electroluminescence element material precursor, the mixing of the lower layer and the upper layer was successfully suppressed at the time of forming the laminated film.

  That is, the organic electroluminescent element material precursor (also referred to as an organic EL element material precursor) according to the present invention is a layer (also referred to as a film) containing the precursor on the indicator substrate directly or via another constituent layer. ), The constituent layer of the organic EL element is formed by performing a process of converting the precursor into an organic EL element material.

<Conversion processing>
The conversion process according to the present invention will be described.

  In the present invention, “conversion treatment” means that the precursor is irradiated by light irradiation (including energy rays such as visible light, infrared rays, ultraviolet rays, electron beams, X-rays, neutron rays, and α rays), heat treatment, and the like. It is defined as a process in which the chemical structure formed changes.

  Among these, in the conversion treatment according to the present invention, ultraviolet irradiation or heat treatment is preferably used. The heat treatment is preferably in the range of 50 ° C. to 200 ° C., and the heating time is preferably in the range of 1 second to 30 minutes from the viewpoint of increasing production efficiency.

  Moreover, as a light source used for an ultraviolet-ray process, the spot light source LIGHTNINGCURE LC8 (made by Hamamatsu Photonics) is mentioned, for example.

  The organic EL element material precursor according to the present invention is converted into an organic EL element material by a conversion process. However, the structure changes before and after the conversion process, and the organic EL element component layer is applied (solution application). It is a compound that greatly changes the solubility in a solvent used for forming a constituent layer.

  Before and after the conversion treatment as described above, from the viewpoint of adjusting the solubility in the solvent used for the application (solution preparation) of the organic EL element constituent layer, the molecular weight A of the organic electroluminescence element material precursor in the precursor-containing layer, It is preferable that the molecular weight B of the organic electroluminescence element material formed by the conversion process of the precursor satisfies the following inequality (1).

Inequality (1)
Molecular weight A> Molecular weight B
Here, the above inequality (1) indicates that when the chemical structure is changed from the organic electroluminescent element material precursor to the organic electroluminescent element material, the partial structure of the precursor is changed, for example, elimination of substituents, A preferred embodiment is that the molecular weight A of the precursor changes due to the occurrence of chemical bond cleavage or the like.

  In addition, when elimination of a substituent, cleavage of a chemical bond, or the like occurs, the desorbed substituent or a molecule generated by cleavage of a chemical bond may cause the characteristics of the organic electroluminescence element material or the organic electroluminescence element. It is preferable not to have an unfavorable influence, and further, it is preferable that the organic electroluminescence element is easily removed out of the system.

  The organic EL device manufacturing method of the present invention proposes a method for efficiently laminating organic EL device materials that exhibit high performance by devising a compound that causes structural changes as described above. The production method using the EL element material precursor enables continuous production of organic EL elements without using special conditions such as conventionally known high vacuum.

  As the organic electroluminescence device material precursor according to the present invention, various materials (emission layer host material, dopant, hole transport material, hole blocking material, electron injection material, electron used for the organic EL device configuration described later) Transport materials, hole injection materials, etc.) can be used as the host nucleus for precursor synthesis.

  Hereinafter, although the specific example of the compound used as an organic electroluminescent element material precursor which concerns on this invention is shown, this invention is not limited to these.

  The synthesis of the organic electroluminescence device material precursor according to the present invention is described in Chem. Lett. , 2002, 2, 134-135, Chem. Commun. 1998, 1661-1662, J. MoI. Org. Chem. 1986, 51, 2139; Chem. Sci. Perkin Trans. 1, 1996, 3161; Am. Chem. Soc. 2004, 126, 12740; Am. Chem. Soc. , 2004, 126, 1596, and can be synthesized.

<< Constituent layers of organic EL elements >>
As an example of an element manufactured by the method for manufacturing an organic thin film element of the present invention, an organic electroluminescence element (organic El element) can be given.

  The constituent layers of the organic EL element of the present invention will be described. In this invention, although the preferable specific example of the layer structure of an organic EL element is shown below, this invention is not limited to these.

(I) Anode / light emitting layer / electron transport layer / cathode (ii) Anode / hole transport layer / light emitting layer / electron transport layer / cathode (iii) Anode / hole transport layer / light emitting layer / hole blocking layer / electron Transport layer / cathode (iv) Anode / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode (v) Anode / anode buffer layer / hole transport layer / light emitting layer / hole Blocking layer / electron transport layer / cathode buffer layer / cathode In the organic EL device of the present invention, the blue light emitting layer preferably has a light emission maximum wavelength of 430 nm to 480 nm, and the green light emitting layer has a light emission maximum wavelength of 510 nm to 550 nm, The red light emitting layer is preferably a monochromatic light emitting layer having a light emission maximum wavelength in the range of 600 nm to 640 nm, and a display device using these is preferably used.

  Further, a white light emitting layer may be formed by laminating at least three light emitting layers, and a non-light emitting intermediate layer may be provided between the light emitting layers. The organic EL element of the present invention is preferably a white light emitting layer, and an illumination device using these is preferably used.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  The details of the cathode buffer layer (electron injection layer) are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, etc., specifically, strontium, aluminum, etc. Examples include a metal buffer layer represented by an alkali metal compound buffer layer represented by lithium fluoride, an alkaline earth metal compound buffer layer represented by magnesium fluoride, and an oxide buffer layer represented by aluminum oxide.

  The buffer layer (injection layer) is preferably a very thin film, and the film thickness is preferably in the range of 0.1 nm to 5 μm although it depends on the material.

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

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

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

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

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

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

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

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

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

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

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

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

  Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N, N ', N'-tetraphenyl-4,4'-diaminophenyl; N, N'-diphenyl-N, N'- Bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (TPD); 2,2-bis (4-di-p-tolylaminophenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ′, N′-tetra-p-tolyl-4,4′-diaminobiphenyl; 1,1-bis (4-di-p-tolyl) Aminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-p-tolylaminophenyl) phenylmethane; N, N'-diphenyl-N, N ' − (4-methoxyphenyl) -4,4'-diaminobiphenyl; N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) quadriphenyl; N, N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenylamino- (2-diphenylvinyl) benzene; 3-methoxy-4′-N, N-diphenylaminostilbenzene; N-phenylcarbazole, and 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 4,4 ', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 88 are linked in a starburst type ( MTDATA) and the like.

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

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

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

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

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

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

  Conventionally, in the case of a single electron transport layer and a plurality of layers, an electron transport material (also serving as a hole blocking material) used for an electron transport layer adjacent to the light emitting layer on the cathode side is injected from the cathode. Any material may be used as long as it has a function of transferring electrons to the light-emitting layer, and any material can be selected from conventionally known compounds.

  Examples include nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives, and the like.

  Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material.

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

In addition, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq ₃ ), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) Aluminum, tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), etc., and the central metals of these metal complexes are In, Mg Metal complexes replaced with Cu, Ca, Sn, Ga, or Pb can also be used as electron transport materials.

  In addition, metal-free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transporting material.

  In addition, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as an electron transport material, and an inorganic semiconductor such as n-type-Si, n-type-SiC, etc. as in the case of the hole injection layer and the hole transport layer. Can also be used as an electron transporting material.

  The electron transport layer can be formed by thinning the electron transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method.

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

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

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

"anode"
As the anode in the organic EL element, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (4 eV or more) is preferably used. Specific examples of such electrode substances include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ , and ZnO. Alternatively, an amorphous material such as IDIXO (In ₂ O ₃ —ZnO) capable of forming a transparent conductive film may be used.

  For the anode, these electrode materials may be formed into a thin film by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method, or when pattern accuracy is not 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.

  Further, although the film thickness depends on the material, it is usually selected in the range of 10 nm to 1000 nm, preferably 10 nm to 200 nm.

"cathode"
On the other hand, as the cathode, a material having a low work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof as an electrode material is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like.

Among these, from the point of durability against electron injection and oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than this, for example, a magnesium / silver mixture, Suitable are a magnesium / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide (Al ₂ O ₃ ) mixture, a lithium / aluminum mixture, aluminum and the like.

  The cathode can be produced by forming a thin film of these electrode materials by vapor deposition or sputtering. The sheet resistance as a cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 nm to 200 nm.

  In order to transmit the emitted light, if either one of the anode or the cathode of the organic EL element is transparent or translucent, the light emission luminance is improved, which is convenient.

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

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

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

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

  As a material for forming the barrier film, any material may be used as long as it has a function of suppressing intrusion of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like can be used.

  Further, in order to improve the brittleness of the film, it is more preferable to have a laminated structure of these inorganic layers and organic material layers. Although there is no restriction | limiting in particular about the lamination | stacking order of an inorganic layer and an organic layer, It is preferable to laminate | stack both alternately several times.

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

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

  The external extraction efficiency at room temperature of light emission of the organic EL device of the present invention is preferably 1% or more, more preferably 5% or more.

  Here, the external extraction quantum efficiency (%) = the number of photons emitted to the outside of the organic EL element / the number of electrons sent to the organic EL element × 100.

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

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

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

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

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

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

  Specific examples of the adhesive include photocuring and thermosetting adhesives having reactive vinyl groups such as acrylic acid oligomers and methacrylic acid oligomers, and moisture curing adhesives such as 2-cyanoacrylates. be able to.

  Moreover, heat | fever and chemical curing types (two-component mixing), such as an epoxy type, can be mentioned. Moreover, hot-melt type polyamide, polyester, and polyolefin can be mentioned. Moreover, a cationic curing type ultraviolet curing epoxy resin adhesive can be mentioned.

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

  In addition, it is also preferable that the electrode and the organic layer are coated on the outside of the electrode facing the support substrate with the organic layer interposed therebetween, and an inorganic or organic layer is formed in contact with the support substrate to form a sealing film. . In this case, the material for forming the film may be any material that has a function of suppressing intrusion of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like may be used. it can. Further, in order to improve the brittleness of the film, it is preferable to have a laminated structure of these inorganic layers and layers made of organic materials.

  The method for forming these films is not particularly limited. For example, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster-ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma A polymerization method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used.

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

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

《Protective film, protective plate》
In order to increase the mechanical strength of the element, a protective film or a protective plate may be provided on the outer side of the sealing film on the side facing the support substrate with the organic layer interposed therebetween or on the sealing film. In particular, when the sealing is performed by the sealing film, the mechanical strength is not necessarily high. Therefore, it is preferable to provide such a protective film and a protective plate.

  As a material that can be used for this, the same glass plate, polymer plate / film, metal plate / film, and the like used for the sealing can be used, but the polymer film is light and thin. Is preferably used.

《Light extraction》
The organic EL element emits light inside a layer having a refractive index higher than that of air (refractive index is about 1.7 to 2.1) and can extract only about 15% to 20% of the light generated in the light emitting layer. It is generally said.

  This is because light incident on the interface (interface between the transparent substrate and air) at an angle θ greater than the critical angle causes total reflection and cannot be taken out of the device, or between the transparent electrode or light emitting layer and the transparent substrate. This is because the light is totally reflected between the light and the light is guided through the transparent electrode or the light emitting layer, and as a result, the light escapes in the direction of the element side surface.

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

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

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

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

  Examples of the low refractive index layer include aerogel, porous silica, magnesium fluoride, and a fluorine-based polymer.

  Since the refractive index of the transparent substrate is generally about 1.5 to 1.7, the low refractive index layer preferably has a refractive index of about 1.5 or less. Further, it is preferably 1.35 or less.

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

  The method of introducing a diffraction grating into an interface or any medium that causes total reflection is characterized by a high effect of improving light extraction efficiency.

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

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

  However, by making the refractive index distribution a two-dimensional distribution, light traveling in all directions is diffracted, and light extraction efficiency is increased.

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

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

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

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

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

  As the condensing sheet, for example, a sheet that is put into practical use in an LED backlight of a liquid crystal display device can be used. As such a sheet, for example, a brightness enhancement film (BEF) manufactured by Sumitomo 3M Limited can be used.

  As the shape of the prism sheet, for example, the base material may be formed by forming a △ -shaped stripe having a vertex angle of 90 degrees and a pitch of 50 μm, or the vertex angle is rounded and the pitch is changed randomly. Other shapes may be used.

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

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

  Further, in the production of the organic thin film 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 element may be patterned. In the fabrication of the element, a conventionally known method is used. Can do.

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

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

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these. In addition, the compound used for an Example is shown below.

Example 1
<< Production of Organic EL Element 1-1 >>
A transparent substrate (NA Techno Glass NA45), in which ITO (Indium Tin Oxide) is formed to 100 nm on a 100 mm × 100 mm × 1.1 mm glass substrate as an anode, is patterned, and this ITO transparent electrode is provided. The support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and UV ozone cleaned for 5 minutes.

  This substrate was attached to a commercially available spin coater, and a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water at 3000 rpm, After forming a film by spin coating in 30 seconds, the film was dried at 200 ° C. for 1 hour to provide a hole injection layer having a thickness of 30 nm.

This transparent support substrate is fixed to a substrate holder of a commercially available vacuum deposition apparatus, while 200 mg of α-NPD is put in a molybdenum resistance heating boat, and 200 mg of CBP as a host compound is put in another resistance heating boat made of molybdenum. 100 mg of Ir-16 was put in a resistance heating boat made of molybdenum, and 200 mg of Alq ₃ was put in another resistance heating boat made of molybdenum, and attached to a vacuum deposition apparatus.

Next, after the pressure in the vacuum chamber was reduced to 4 × 10 ⁻⁴ Pa, the heating boat containing α-NPD was energized and heated, and deposited on the transparent support substrate at a deposition rate of 0.1 nm / second. The positive hole transport layer was provided.

  Furthermore, the heating boat containing CBP and Ir-16 was energized and heated, and co-deposited on the hole transport layer at a deposition rate of 0.2 nm / second and 0.012 nm / second, respectively, to obtain a film thickness of 40 nm. The light emitting layer was provided. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  This substrate was again attached to the spin coater, spin-coated under a condition of 1000 rpm for 30 seconds using a solution of 60 mg of bathocuproine (BCP) in 6 ml of toluene (film thickness of about 10 nm), and vacuum-dried at 60 ° C. for 1 hour. Then, heat treatment was performed at 180 ° C. for 1 hour to provide a hole blocking layer (film thickness of about 40 nm).

Subsequently, the heating boat containing Alq ₃ was energized and heated, and was deposited on the hole blocking layer at a deposition rate of 0.1 nm / second to further provide an electron transport layer having a thickness of 40 nm. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  After completion of the heat treatment, 0.5 nm of lithium fluoride and 110 nm of aluminum were deposited to form a cathode, and an organic EL element 1-1 was produced.

<< Production of Organic EL Elements 1-2 to 1-5 >>
In the production of the organic EL element 1-1, except that the BCP used as the hole blocking layer and its coating solvent were replaced as shown in Table 1, the same method as the organic EL element 1-1 was used. 5 was produced.

  In addition, about organic EL element 1-3 to 1-5, exemplary compound 3-3, 3-5, 3-9 is used as an organic electroluminescent element material precursor based on this invention at the time of formation of a hole-blocking layer. Each of the cyclohexane solutions contained is used, and after the layer containing the precursor is formed in the light emitting layer, heat treatment is performed at 180 ° C. for 1 hour to convert each of the precursors into a hole blocking material. Each of the hole blocking layers containing the hole blocking material was formed.

<< Evaluation of Organic EL Elements 1-1 to 1-5 >>
The organic EL elements 1-1 to 1-5 produced as follows were evaluated.

《External extraction quantum efficiency》
About each of the produced organic EL elements 1-1 to 1-5, an external extraction quantum efficiency (%) was measured when a constant current of ^2.5 mA / cm ² was applied at 23 ° C. in a dry nitrogen gas atmosphere. It is shown in Table 1 below. For the measurement, a spectral radiance meter CS-1000 (manufactured by Minolta) was used.

  The measurement result of the external extraction quantum efficiency was expressed as a relative value when the measured value of the organic EL element 1-1 was set to 100.

<Luminescent life>
When driven at a constant current of 2.5 mA / cm ^2, the luminance is to measure the time required to drop to half of the emission immediately after the start of the luminance (initial luminance), the half life time which (tau ^{0. 5} ) As an index of life. A spectral radiance meter CS-1000 (manufactured by Minolta) was used for the measurement.

  In addition, the measurement result of the light emission lifetime was represented by the relative value when the measured value of the organic EL element 1-1 was 100.

  The results obtained are shown below.

Organic EL Hole blocking material (precursor *) External extraction Luminescence Remark Element No. / Coating solvent material Quantum efficiency (%) Life 1-1 BCP / toluene 100 100 Comparative example 1-2 BCP / cyclohexane 8 22 Comparative example 1-3 3-2 * / cyclohexane 329 521 Invention 1-4 3-5 * / Cyclohexane 432 480 The present invention 1-5 3-9 * / cyclohexane 381 621 The present invention Exemplified compounds 3-2 and 3-5 used for forming the hole blocking layer of the organic EL devices 1-3 to 1-5 , 3-9 are each an organic EL element material precursor.

  From the above, it is clear that the organic EL element of the present invention achieves higher efficiency and longer life than the comparative organic EL element.

Example 2
<< Preparation of Organic EL Element 2-1 >>
Transparent support provided with this ITO transparent electrode after patterning on a substrate (NH45 manufactured by NH Techno Glass) made of ITO (indium tin oxide) with a thickness of 100 nm on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode The substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  This substrate was attached to a commercially available spin coater, and a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water at 3000 rpm, After forming a film by spin coating in 30 seconds, the film was dried at 200 ° C. for 1 hour to provide a hole injection layer having a thickness of 30 nm.

  After completion of the drying treatment, the substrate was again attached to the spin coater, and a solution obtained by dissolving Exemplified Compound 4-4 (60 mg) in 6 ml of toluene was spin-coated at 1000 rpm for 30 seconds (film thickness 40 nm), and 1 at 60 ° C. After vacuum drying for a period of time, ultraviolet treatment (irradiation with ultraviolet rays for 5 minutes) was performed to form a hole transport layer.

Next, this substrate is fixed to a substrate holder of a vacuum deposition apparatus, 200 mg of CBP is put into a molybdenum resistance heating boat, 200 mg of Ir-1 is put into another molybdenum resistance heating boat, and Vasocuproine is put into another molybdenum resistance heating boat. 200 mg of (BCP) was put, and 200 mg of Alq ₃ was put in another resistance heating boat made of molybdenum, and attached to a vacuum deposition apparatus.

After reducing the vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat containing CBP and Ir-1 was energized and heated, and the holes were deposited at a deposition rate of 0.2 nm / second and 0.012 nm / second, respectively. A 40 nm-thick luminescent layer was provided by co-evaporation on the transport layer.

  Then, it supplied with electricity to the said heating boat containing BCP, heated, and vapor-deposited on the said light emitting layer with the vapor deposition rate of 0.1 nm / sec, and also provided the 10-nm-thick hole blocking layer.

Subsequently, the heating boat containing Alq ₃ was energized and heated, and was deposited on the hole blocking layer at a deposition rate of 0.1 nm / second to further provide an electron transport layer having a thickness of 40 nm. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Then, 0.5 nm of lithium fluoride and 110 nm of aluminum were vapor-deposited, the cathode was formed, and the organic EL element 2-1 was produced. When this element was energized, green light emission was obtained, and it was found that it could be used as an organic EL display device.

  Furthermore, the same result was obtained even if Exemplified Compound 4-4 was replaced by 4-1, 4-3, 4-8, 4-9, 4-12, 4-13, 4-15, respectively.

Example 3
<< Production of Organic EL Element 3-1 >>
Transparent support provided with this ITO transparent electrode after patterning on a substrate (NH45 manufactured by NH Techno Glass) made of ITO (indium tin oxide) with a thickness of 100 nm on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode The substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  This substrate was attached to a commercially available spin coater, and a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water at 3000 rpm, After forming a film by spin coating in 30 seconds, the film was dried at 200 ° C. for 1 hour to provide a hole injection layer having a thickness of 30 nm.

  After completion of the drying treatment, the substrate is again attached to the spin coater, and a solution prepared by dissolving Exemplified Compound 4-4 (60 mg), which is a hole transport material precursor, in 6 ml of cyclohexane is spin-coated at 1000 rpm for 30 seconds (film). After vacuum drying at 60 ° C. for 1 hour at a temperature of 60 ° C., a conversion treatment (180 ° C., heat treatment for 30 minutes) was performed to form a hole transport layer containing a hole transport material.

  Next, the substrate was attached to the spin coater in the same manner as in the formation of the hole transport layer, and a solution of Exemplified Compound 1-4 (60 mg) and Exemplified Compound 2-1 (3 mg) dissolved in 6 ml of cyclohexane was 1000 rpm for 30 seconds. Then, after spin coating (film thickness 40 nm) and vacuum drying at 60 ° C. for 1 hour, a conversion treatment (heat treatment at 180 ° C. for 30 minutes) was performed to form a light emitting layer containing a light emitting material.

  Subsequently, the substrate was attached to a spin coater, and a solution prepared by dissolving Exemplified Compound 3-3 (60 mg) in 6 ml of cyclohexane was spin-coated at 1000 rpm for 30 seconds (film thickness 40 nm) and vacuum-dried at 60 ° C. for 1 hour. Then, a conversion treatment (180 ° C., 30 minutes heat treatment) was performed to form a hole blocking layer containing a hole blocking material.

Next, this substrate was fixed to a substrate holder of a vacuum deposition apparatus, 200 mg of Alq ₃ was placed in a molybdenum resistance heating boat, and attached to the vacuum deposition apparatus. After reducing the vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat containing Alq ₃ was energized and heated, and deposited on the hole blocking layer at a deposition rate of 0.1 nm / sec. An electron transport layer having a thickness of 40 nm was provided. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Then, 0.5 nm of lithium fluoride and 110 nm of aluminum were vapor-deposited, the cathode was formed, and the organic EL element 3-1 was produced.

  When the obtained organic EL element 3-1 was energized, green light emission was obtained, and it was found that it could be used as an organic EL display device.

Example 4
<< Preparation of Organic EL Element 4-1 >>: Preparation of White Illumination Device In the preparation of organic EL element 3-1 of Example 1, Illustrative Compound 2- which is an organic EL element material precursor used for forming the light emitting layer Instead of using 1 (3 mg), the organic EL element 4-1 was similarly obtained except that Ir-1 (0.9 mg), Ir-9 (0.9 mg), and Ir-15 (1.2 mg) were substituted. Was made.

<< Evaluation of Organic EL Element 4-1 >>
When evaluating the obtained organic EL element 4-1, the non-light emitting surface of the organic EL element 4-1 after production was covered with a glass case, and a glass substrate having a thickness of 300 μm was used as a sealing substrate. As a sealing material, an epoxy photo-curing adhesive (Lux Track LC0629B manufactured by Toagosei Co., Ltd.) is applied, and this is overlaid on the cathode and brought into close contact with the transparent support substrate, and UV light is irradiated from the glass substrate side. Then, it was cured and sealed to form a lighting device as shown in FIGS.

  FIG. 1 shows a schematic diagram of a lighting device, in which an organic EL element 101 is covered with a glass cover 102 (in addition, sealing with a glass cover is performed in a nitrogen atmosphere without bringing the organic EL element 101 into contact with the atmosphere. (In a high purity nitrogen gas atmosphere with a purity of 99.999% or more).

  FIG. 1 shows a cross-sectional view of the lighting device. In FIG. 2, 105 denotes a cathode, 106 denotes an organic EL layer, and 107 denotes a glass substrate with a transparent electrode. The glass cover 102 is filled with nitrogen gas 108 and a water catching agent 109 is provided.

  When the organic EL element 4-1 was energized, almost white light was obtained, and it was found that it could be used as a lighting device.

It is the schematic of an illuminating device. It is sectional drawing of an illuminating device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Organic EL element 102 Glass cover 105 Cathode 106 Organic EL layer 107 Glass substrate with a transparent electrode 108 Nitrogen gas 109 Water catching agent

Claims (14)

In a method for producing an organic electroluminescent device having at least an anode and a cathode on a support substrate, and having an organic layer including at least one light emitting layer between the anode and the cathode,
The manufacturing method of the organic electroluminescent element characterized by having the process of forming at least one layer of this organic layer using an organic electroluminescent element material precursor. Step of providing a precursor-containing layer by applying a solution or dispersion containing an organic electroluminescence element material precursor, and then converting the organic electroluminescence element material precursor in the precursor-containing layer into an organic electroluminescence element material The method for producing an organic electroluminescent element according to claim 1, further comprising a step of forming at least one organic layer by performing a conversion process. The method further comprises forming an organic compound-containing layer on at least one organic layer containing the organic electroluminescence element material formed by converting the organic electroluminescence element material precursor. The manufacturing method of the organic electroluminescent element of 1 or 2. The method for producing an organic electroluminescent element according to claim 1, wherein the conversion treatment of the organic electroluminescent element material precursor includes an ultraviolet irradiation step. The method for producing an organic electroluminescent element according to claim 1, wherein the conversion treatment of the organic electroluminescent element material precursor includes a heat treatment step. The molecular weight A of the organic electroluminescent element material precursor in the precursor-containing layer and the molecular weight B of the organic electroluminescent element material formed by the conversion treatment of the precursor satisfy the following inequality (1). The manufacturing method of the organic electroluminescent element of any one of Claims 2-5 characterized by these.
Inequality (1)
Molecular weight A> Molecular weight B An organic electroluminescent element manufactured by the method for manufacturing an organic electroluminescent element according to claim 1. The organic electroluminescent element according to claim 7, comprising a plurality of organic layers formed using the organic electroluminescent element material precursor. 9. The organic electroluminescence according to claim 7, wherein at least one of the organic layers formed using the organic electroluminescence element material precursor is provided between the cathode layer and the light emitting layer. element. 9. The organic electroluminescence according to claim 7, wherein at least one of the organic layers formed using the organic electroluminescence element material precursor is provided between the anode layer and the light emitting layer. element. The organic electroluminescence device according to claim 7, wherein the organic electroluminescence device has an organic layer containing a phosphorescent compound as a constituent layer. The organic electroluminescence element according to any one of claims 7 to 11, which emits white light. A display device comprising the organic electroluminescence element according to claim 7. An illuminating device comprising the organic electroluminescence element according to any one of claims 7 to 12.

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