JP6123438B2 - ORGANIC ELECTROLUMINESCENCE ELEMENT, LIGHTING DEVICE AND DISPLAY DEVICE HAVING THE SAME - Google Patents

Description

  The present invention relates to an organic electroluminescence element having excellent luminous efficiency, low driving voltage, and long life, and an illumination device and a display device including the organic electroluminescence element.

  An organic electroluminescence element (hereinafter also referred to as an organic EL element) is an organic thin film layer (single layer portion or multilayer portion) having a thickness of only about 0.1 μm containing an organic light emitting substance between an anode and a cathode. It is a thin film type all solid-state element to be configured. When a relatively low voltage of about 2 to 20 V is applied to such an organic EL element, electrons are injected from the cathode and holes are injected from the anode into the organic thin film layer. It is known that excitons are generated by recombination of electrons and holes in the light-emitting layer, and emission (fluorescence / phosphorescence) is obtained when the excitons are deactivated. This technology is expected as a display and lighting.

  An LED (Light Emitting Diode) element is known as an element that emits light based on the same principle, but there is a great difference between the two. The thin film constituting the organic EL element uses an amorphous thin film regardless of whether it is organic or inorganic, whereas the LED element uses a crystal. The great merit of this crystal is that it is highly conductive and excellent in the stability of the material and film over time of heat and driving. As a result, high brightness and long life performance, which are generally known as characteristics of LED elements, are achieved.

  On the other hand, the biggest demerit in the LED is that the function of the entire crystal is exhibited. Therefore, if there are crystal defects (crystal grain boundaries), the carrier traps and exciton quenching occur, and the light emission function is hindered. For this reason, it becomes difficult to reduce the generation probability of crystal defects, that is, to increase the size of each element. In fact, at present, the expansion of the light emitting area can only be solved by integrating a plurality of elements.

  On the other hand, in organic EL elements, amorphous films are used instead of crystals, and developments for issues derived from amorphous films such as improvement of amorphousness (suppression of crystallinity) and improvement of thermal stability are actively conducted. It is a well-known fact.

  As an example of focusing on crystalline materials, not amorphous materials that have fundamental problems in improving the performance of organic EL elements. For example, Patent Document 1 discloses a technique in which quantum dots are used as a light emitting layer material, the hole mobility of a hole transport material forming a hole transport layer is adjusted, and an electron blocking ability is provided. For example, Patent Document 2 discloses a light emitting device having an exciton generation layer sandwiched between two quantum dot monomolecular films. However, in these methods, the amount of quantum dots that easily cause concentration quenching is limited, so that the light emission efficiency is not sufficient.

JP 2006-190682 A JP 2009-87754 A

  The present invention has been made in view of the above-described problems and circumstances, and a problem to be solved is to provide an organic electroluminescence element having excellent luminous efficiency, low driving voltage, and long life. Moreover, it is providing the illuminating device and display apparatus provided with this organic electroluminescent element.

  In order to solve the above-mentioned problems, the present inventor has focused on a crystalline material, not an amorphous material having a principle problem, for the cause of the above-described problems. Furthermore, for the purpose of increasing the area, we investigated the inhibition of the light emission function caused by the crystal grain boundary, not the single crystal without the crystal grain boundary as required for the LED which still has a big problem. As a result, as described later, when nanocrystal particles having a large number of crystal grain boundaries in the bulk (layer) are used, a great suppression effect on the inhibition of the light emitting function caused by the crystal grain boundaries has been found.

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

  1. An organic electroluminescence device having a light emitting layer and two charge transport layers adjacent to both sides of the light emitting layer between a cathode and an anode, wherein the light emitting layer and the two charge transport layers An organic electroluminescence device, wherein at least one of the layers contains nanocrystalline particles.

  2. 2. The organic electroluminescence device according to claim 1, wherein the charge transport layer on the cathode side adjacent to the light emitting layer contains the nanocrystal particles.

  3. 2. The organic electroluminescence device according to claim 1, wherein the charge transport layer on the anode side adjacent to the light emitting layer contains the nanocrystal particles.

  4). Item 4. The organic electroluminescence element according to any one of Items 1 to 3, wherein the nanocrystalline particles contained in the charge transport layer are organic nanocrystalline particles.

  5. Item 4. The organic electroluminescence device according to any one of Items 1 to 3, wherein the nanocrystalline particles contained in the charge transport layer are inorganic nanocrystalline particles.

  6). 6. The organic electroluminescence device according to item 5, wherein the inorganic nanocrystal particles are metal, metal salt or metal oxide nanocrystal particles.

  7). An organic electroluminescence device according to any one of items 1 to 6, wherein the organic electroluminescence device exhibits white light emission.

  8). An organic electroluminescence element according to any one of items 1 to 7 is provided.

  9. A display device comprising the organic electroluminescence element according to any one of items 1 to 7.

  By the above means of the present invention, it is possible to provide an organic electroluminescence device having excellent luminous efficiency, low driving voltage and long life. Moreover, the illuminating device and display apparatus provided with this 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. That is, in an organic EL device consisting of a nanocrystalline particle (polycrystalline) film rather than a normal organic EL device consisting of an amorphous film, the charge transporting property to the grain boundary caused by the polycrystal is improved (suppressing carrier traps) and light emission. It is considered that the recombination of electrons and holes in the light emitting layer has been made efficient as a result of the improvement of the property (suppression of exciton trap, improvement of recombination, suppression of quenching).

Example of schematic diagram of nanocrystal Schematic diagram showing an example of a display device composed of organic EL elements Schematic diagram of display part A Pixel circuit diagram Schematic diagram of passive matrix type full color display device Schematic of lighting device Schematic diagram of lighting device

  The organic electroluminescent device of the present invention is an organic electroluminescent device having a light emitting layer and two charge transport layers adjacent to both sides of the light emitting layer between a cathode and an anode, In addition, at least one of the two charge transport layers contains nanocrystalline particles. This feature is a technical feature common to the inventions according to claims 1 to 9.

  As an embodiment of the present invention, it is preferable that the charge transport layer on the cathode side adjacent to the light emitting layer contains the nanocrystal particles. Moreover, it is preferable that the said charge transport layer of the anode side adjacent to the said light emitting layer contains the said nanocrystal particle.

  Furthermore, in the present invention, the nanocrystal particles contained in the charge transport layer are preferably organic nanocrystal particles. This gives:

  Moreover, it is preferable that the nanocrystal particles contained in the charge transport layer are inorganic nanocrystal particles. Further, the inorganic nanocrystal particles are preferably metal, metal salt or metal oxide nanocrystal particles. It is preferable that the organic electroluminescence device exhibits white light emission.

  The organic EL element of the present invention can be suitably included in a lighting device and a display device.

  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.

  Hereinafter, although the form for implementing this invention is demonstrated in detail, this invention is not limited to these.

<< Constitutional layer of organic EL element >>
As typical element structures in the organic EL element of the present invention, the following structures can be raised, but are not limited thereto.

  The charge transport layer is a layer in which charge transfer occurs when a voltage is applied to the organic EL element. Specific examples include a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer, and an electron injection layer. However, the light emitting layer is excluded in the present invention.

The organic EL device of the present invention has two charge transport layers adjacent to both sides of the light emitting layer.
(1) Anode / hole transport layer / light emitting layer / electron transport layer / cathode (2) Anode / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode (3) Anode / hole injection layer / Hole transport layer / light emitting layer / electron transport layer / cathode (4) anode / hole injection layer / hole transport layer / (electron blocking layer /) light emitting layer / (hole blocking layer /) electron transport layer / electron injection Layer / Cathode Among the above, the configuration (4) is preferably used, but is not limited thereto.

  The light emitting layer according to the present invention is composed of a single layer or a plurality of layers, and when there are a plurality of light emitting layers, a non-light emitting intermediate layer may be provided between the light emitting layers.

  If necessary, a hole blocking layer (also referred to as a hole blocking layer) or an electron injection layer (also referred to as a cathode buffer layer) may be provided between the light emitting layer and the cathode. An electron blocking layer (also referred to as an electron barrier layer) or a hole injection layer (also referred to as an anode buffer layer) may be provided therebetween.

  The electron transport layer according to the present invention is a layer 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. Moreover, you may be comprised by multiple layers.

  The hole transport layer according to the present invention is a layer 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. Moreover, you may be comprised by multiple layers.

  In the above typical element configuration, the layer excluding the anode and the cathode is also referred to as an organic layer.

(Tandem structure)
Further, the organic EL element according to the present invention may be an element having a so-called tandem structure in which a plurality of light emitting units including at least one light emitting layer are stacked. As typical element configurations of the tandem structure, for example, the following configurations can be given.
(5) Anode / first light emitting unit / intermediate layer / second light emitting unit / intermediate layer / third light emitting unit / cathode Here, the first light emitting unit, the second light emitting unit and the third light emitting unit are all the same. Or different. Two light emitting units may be the same, and the remaining one may be different.

  A plurality of light emitting units may be laminated directly or via an intermediate layer, and the intermediate layer is generally an intermediate electrode, an intermediate conductive layer, a charge generation layer, an electron extraction layer, a connection layer, an intermediate layer. A known material structure can be used as long as it is also called an insulating layer and has a function of supplying electrons to the anode-side adjacent layer and holes to the cathode-side adjacent layer.

Examples of the material used for the intermediate layer include ITO (indium tin oxide), IZO (indium zinc oxide), ZnO ₂ , TiN, ZrN, HfN, TiOx, VOx, CuI, InN, GaN, and CuAlO _2. , CuGaO ₂ , SrCu ₂ O ₂ , LaB ₆ , RuO ₂ , Al, etc., conductive inorganic compound layers, Au / Bi ₂ O _3, etc., two-layer films, SnO ₂ / Ag / SnO ₂ , ZnO / Ag / ZnO, Bi ₂ O ₃ / Au / Bi ₂ O ₃ , TiO ₂ / TiN / TiO ₂ , TiO ₂ / ZrN / TiO _{2 and} other multilayer films, C _{60 and} other fullerenes, conductive organic layers such as oligothiophene Conductive organic compound layers such as metal phthalocyanines, metal-free phthalocyanines, metal porphyrins, metal-free porphyrins, etc. The invention is not limited to these.

  Examples of a preferable configuration in the light emitting unit include those in which the anode and the cathode are excluded from the configurations (1) to (4) described in the above representative element configurations, but the present invention is limited to these. Not.

  Specific examples of the tandem organic EL element include, for example, US Pat. No. 6,337,492, US Pat. No. 7,420,203, US Pat. No. 7,473,923, US Pat. No. 6,872, No. 472, US Pat. No. 6,107,734, US Pat. No. 6,337,492, International Publication No. 2005/009087, JP-A 2006-228712, JP-A 2006-24791, JP-A 2006 -49393, JP-A-2006-49394, JP-A-2006-49396, JP-A-2011-96679, JP-A-2005-340187, JP-A-4711424, JP-A-3496681, Patent Japanese Patent No. 3884564, Japanese Patent No. 431169, Japanese Patent Laid-Open No. 2010-192719, Japanese Patent Laid-Open No. 2009-0. 6929, JP 2008-078414 A, JP 2007-059848 A, JP 2003-272860 A, JP 2003-045676 A, International Publication No. 2005/094130, etc. However, the present invention is not limited to these.

  The organic electroluminescent device of the present invention is an organic electroluminescent device having a light emitting layer and two charge transport layers adjacent to both sides of the light emitting layer between a cathode and an anode, At least one of the two charge transport layers contains nanocrystal particles.

《Nanocrystalline particles》
Until now, the film of each organic layer forming the organic EL device is preferably an amorphous film, that is, a crystalline film is not suitable. It has been explained that this is because charge trapping at the crystal grain boundary adversely affects. However, in the present invention, as will be described later, when a layer containing nanocrystalline particles is installed as a charge transport layer adjacent to a light emitting layer containing nanocrystalline particles, charge injection between the layer adjacent to the light emitting layer and the light emitting layer is performed as follows. While accelerated, it was found that the charge trapping function is improved in the light emitting layer, and that the light emission efficiency can be improved with a relatively simple layer structure.

  Here, the nanocrystal particles used in the present invention will be further described. The nanocrystal particle indicates a polycrystal having a particle size of about 5 nm to 70 nm. It is known that when the particle diameter enters the above-mentioned nano-region, it has unique physical properties. For example, in a metal nanoparticle, the bond between lattices on the metal surface is broken, resulting in an electronically unstable state. In order to stabilize the grains, a grain boundary having an irregular bond state that does not normally occur is formed.

  FIG. 1 is an example of a schematic diagram of a nanocrystal. If each grain is an atom or a molecule, the part of b having a regular arrangement represents one nanocrystal. The part consisting of a which is irregularly arranged between and between the crystals represents a crystal grain boundary. As described above, since the nanocrystal particles in the present invention show an aggregate of fine crystals, a crystal peak by the X-ray diffraction method (XRD method) is observed, whereas a nano-size amorphous in which no peak is observed It is different from particles (fine particles).

  The method for measuring the average particle size of the nanocrystal particles is not particularly limited. For example, the nanocrystal particles are calculated from a photographed image that is observed and photographed with a scanning electron microscope, and the magnification of the microscope is 10,000 times. It is possible to use a method of setting and taking a photograph and calculating from a photograph image.

  Large crystals (powder and bulk crystals) with a size of μm or more have already been widely studied and put to practical use. However, in recent years, when they are made into smaller nanosized crystals, nanocrystal particles It is often found that the structure, physical properties, functions, chemical reactivity, etc. change in a more desirable or innovative direction, which is the key state of a substance / material located between an isolated molecule and a bulk crystal. For example, research and development is being promoted. Research on organic nanocrystal particles began in Japan in the early 1990s, 10 years behind inorganic nanocrystal particles. To date, various basic and fundamental potentials have been accumulated, and at the same time, some have already been socially returned as practical technologies.

  First, as a method for producing organic nanocrystal particles, a “reprecipitation method” has been found as a general-purpose production method that can be widely applied to organic materials, which are more thermally unstable than inorganic materials. Has been established. This is a simple and mild technique in which the target compound is dissolved in a good solvent, and the solution is poured into a poor solvent that can be diluted infinitely and reprecipitated. A method has also been developed, and nanocrystal particles of almost all compounds are becoming possible. Recently, the usefulness of the emulsion method of crystallization in oil droplets has also been demonstrated.

  Next, in elucidation of the individuality of organic nanocrystal particles compared to molecular states and bulk crystals, it has been found that, as an example, the color of absorption and emission changes depending on the crystal size. A similar phenomenon has been found in inorganic nanocrystal particles, but it can be said to be a phenomenon unique to organic nanocrystal particles because size dependence is manifested in a size region that is an order of magnitude larger than that of inorganic nanocrystal particles. In addition, the individuality of nanocrystal particles such as higher chemical reactivity, easier single-crystal transition phenomenon, different crystal polymorphism from the bulk, and therefore different physical properties and functions are observed. Has been issued. As a development, it has also been found that an electronic state exceeding additivity is expressed by a composite of organic and inorganic nanocrystal particles.

  As a method for materializing organic nanocrystal particles, in addition to the usual spin coating from dispersion liquid, cumulative thinning technique by electrostatic adsorption, spherical particle formation technique by wrapping nanocrystal particles, dispersion liquid itself as liquid / crystal There are many methods such as the method used as a solidification and the method of solidifying after electric / magnetic orientation in liquid.

  The nanocrystal particles used in the light emitting layer of the organic EL element are preferably organic nanocrystal particles. In this case, it is preferable to form nanocrystalline particles of a light-emitting dopant described later by the method described above, and it is also preferable to use organic nanocrystalline particles combined with a (luminescent) host compound. In addition, the presence of grain boundaries in the layer containing each nanocrystal particle can be easily confirmed by observing the cross section of the layer by SEM (scanning microscope) or TEM (transmission microscope), and can be confirmed by aggregation, fusion, firing, etc. It is preferable that the particle system does not increase or the layer is made uniform (for example, see the Chemical Society of Japan, 5th edition, Experimental Chemistry Course, 28, 266-285 (2005)).

  The expression mechanism or action mechanism of the effect of the present invention is presumed as follows. In the nanocrystal particle, since crystals in a minute region are clustered, a large number of crystal grain boundaries, that is, defects exist. However, as described above, in such a nano-region, an irregular bond state that does not normally occur occurs, and thus the influence of these defects can be ignored. Next, the problem is the grain boundary between the nanocrystal particles. The grain boundary between the nanocrystal particles can be roughly divided into two types.

(1) Functional degradation due to grain boundaries in a single functional layer As will be described in detail below, unlike normal uniform amorphous films, an increase in the injection barrier can be ignored due to electric field concentration occurring between nanocrystalline particles. all right. On the other hand, the decrease in mobility due to carrier traps and the like is not recognized in the light emitting layer due to the improvement of the hole trap, electron block and exciton block functions due to the improvement of the carrier trap performance, but rather the luminous efficiency is improved. Occurred.

(2) Degradation of function due to grain boundaries between adjacent functional layers In particular, for item (2), material properties (highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO), Fermi The level, work function, charge transportability, etc.) are different, so that the material properties have an injection barrier that is more or less regardless of whether it is a nanocrystalline particle or not. For this reason, a further decrease in functionality due to crystal grain boundaries, particularly a decrease in charge injection property, is a fatal problem. However, it has been found that, in an organic EL element that is an application of the present invention, an electric field is generated at the time of use, so that the following charge injection is possible.

  When a layer containing nanocrystalline particles is placed in the charge transport layer adjacent to the light emitting layer containing nanocrystalline particles, that is, in the case of (2) above, in the layer containing nanocrystalline particles, a normal uniform layer is used. Unlike an amorphous film, an electric field is applied only to the particle portion, resulting in electric field concentration. It was found that the injection barrier can be canceled by this electric field concentration.

  (3) From this, it has been clarified that the relaxation of the injection barrier in the layer containing nanocrystal particles from the amorphous film in which the electric field concentration does not occur may be considered.

  Considering the well-known configuration of organic EL elements as “anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode”, a hole injection layer, electron injection The characteristics of the layer adjacent to the electrode, such as the layer, are close to the energy level of the other adjacent layer (suppressing the energy barrier) and can be band-bended with the electrode (metal) (energy with the electrode) The difference in level is reduced by band bending).

  In the present invention, since a layer containing nanocrystal particles is disposed in the light emitting layer and its adjacent layer, i) hole injection layer to hole transport layer, ii) electron injection layer to electron transport layer, and iii) hole transport. We studied the relaxation of the injection barrier in the layer containing nanocrystal particles from the amorphous film for the four items from the layer to the light emitting layer, and iv) from the electron transport layer to the light emitting layer.

Regarding relaxation of the injection barrier from the amorphous film to the layer containing nanocrystal particles, from the same viewpoint as the hole or electron injection layer, the layer having a function necessary for the layer adjacent to the light emitting layer is:
i-1) a) a hole transport layer that is close in energy ranking to the light emitting layer and contains nanocrystal particles, and b) a bond bendable hole injection layer.
i-2) a) energy order close to that of the light emitting layer and containing nanocrystalline particles, b) the hole injection layer containing nanocrystalline particles
ii-1) a) an electron transport layer that is close in energy ranking to the light emitting layer and contains nanocrystal particles, and b) can be bond-bended with the electron injection layer,
ii-2) a) The energy ranking is close to that of the light emitting layer and contains nanocrystal particles, b) the electron injection layer is a nanocrystal particle containing layer,
iii) a) a hole transport layer that is close in energy ranking to the light-emitting layer, and b) contains nanocrystal particles or is capable of bond bending,
iv) It is considered to be an electron transport layer in which a) the energy ranking is close to that of the light emitting layer, and b) a nanocrystal particle-containing or bond-bendable.

From the viewpoint of ease of bond bending, metals, metal oxides, and high charge density materials (n-type semiconductors, p-type semiconductors) are candidates. In the present invention, as described above, at least one layer adjacent to the light emitting layer is charged. The transport layer (which means an electron transport layer, an electron injection layer, a hole blocking layer, a hole transport layer, a hole injection layer, an electron blocking layer, etc., which will be described later) contains nanocrystalline particles. May be used in combination. Moreover, about the nanocrystal particle material used, what was manufactured by the method similar to the above and the various materials known as a nanocrystal particle can be used. In particular, in the charge transport layer, inorganic nanocrystal particles are preferable. The inorganic nanocrystal particles are preferably metal, metal salt or metal oxide nanocrystal particles. In particular, it is preferable to use semiconductor or semiconductive inorganic nanocrystal particles. Examples of conductors are metal nanocrystal particles such as silver, gold, copper, and nickel, and semiconductors are preferably inorganic (oxide) semiconductors such as zinc oxide and zinc sulfide. Also included are nanocrystalline particles of materials that exhibit semiconductivity in a special crystalline form.

  Hereinafter, each layer which comprises the organic EL element of this invention is demonstrated.

  As described above, the light emitting layer and two charge transport layers adjacent to the light emitting layer (an electron transport layer, an electron injection layer, a hole blocking layer, a hole transport layer, a hole injection layer, an electron blocking layer, etc. described later) At least one layer of the above-mentioned nanocrystal particles includes the above-described nanocrystalline particles, but the general materials described in each organic layer described below may be used in combination as long as the effects of the present invention are not impaired. .

  Preferably, the charge transport layer on the cathode side adjacent to the light emitting layer contains the nanocrystal particles. Even if the charge transport layer on the anode side adjacent to the light emitting layer contains the nanocrystal particles, the same effect can be obtained.

  The nanocrystal particles contained in the charge transport layer are preferably organic nanocrystal particles. More preferably, the nanocrystal particles contained in the charge transport layer are inorganic nanocrystal particles, and more preferably, the two charge transport layers adjacent to the light emitting layer both contain inorganic nanocrystal particles. It is to be.

<Light emitting layer>
The light emitting layer according to the present invention is a layer that provides a field in which electrons and holes injected from an electrode or an adjacent layer are recombined to emit light via excitons, and the light emitting portion is a layer of the light emitting layer. Even within, it may be the interface between the light emitting layer and the adjacent layer. The structure of the light emitting layer according to the present invention is not particularly limited as long as it satisfies the requirements defined in the present invention.

  The total thickness of the light emitting layer is not particularly limited, but it prevents the uniformity of the film to be formed, the application of unnecessary high voltage during light emission, and the improvement of the stability of the emission color with respect to the driving current. From a viewpoint, it is preferable to adjust to the range of 2 nm-5 micrometers, More preferably, it adjusts to the range of 2 nm-500 nm, More preferably, it adjusts to the range of 5 nm-200 nm.

  The thickness of each light emitting layer of the present invention is preferably adjusted to a range of 2 nm to 1 μm, more preferably adjusted to a range of 2 to 200 nm, and further preferably adjusted to a range of 3 to 150 nm. The

  The light emitting layer of the present invention preferably contains a light emitting dopant (a light emitting dopant compound, a dopant compound, also simply referred to as a dopant) and a host compound (a matrix material, a light emitting host compound, also simply referred to as a host).

(1) Luminescent dopant The luminescent dopant which concerns on this invention is demonstrated.

  As the light emitting dopant, a fluorescent light emitting dopant (also referred to as a fluorescent dopant or a fluorescent compound) and a phosphorescent light emitting dopant (also referred to as a phosphorescent dopant or a phosphorescent compound) are preferably used. In the present invention, it is preferable that at least one light emitting layer contains a phosphorescent light emitting dopant.

  The concentration of the luminescent dopant in the luminescent layer can be arbitrarily determined based on the specific dopant used and the requirements of the device, and is contained at a uniform concentration in the thickness direction of the luminescent layer. It may also have an arbitrary concentration distribution.

  Moreover, the light emission dopant which concerns on this invention may be used in combination of multiple types, and may use it combining the combination of dopants from which a structure differs, and combining a fluorescence emission dopant and a phosphorescence emission dopant. Thereby, arbitrary luminescent colors can be obtained.

  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 a total CS-1000 (manufactured by Konica Minolta Optics) is applied to the CIE chromaticity coordinates.

  In the present invention, it is also preferable that the light emitting layer of one layer or a plurality of layers contains a plurality of light emitting dopants having different emission colors and emits white light.

  There are no particular limitations on the combination of the light-emitting dopants that exhibit white, and examples include blue and orange, and a combination of blue, green, and red.

The white color in the organic EL device of the present invention means that the chromaticity in the CIE 1931 color system at 1000 cd / m ² is x = 0.33 ± 0.09 when the front angle luminance at 2 ° viewing angle is measured by the method described above. , Y = 0.33 ± 0.08.

(1.1) Fluorescent Luminescent Dopant The fluorescent luminescent dopant according to the present invention (hereinafter also referred to as “fluorescent dopant”) will be described.

  The fluorescent dopant according to the present invention is a compound that can emit light from an excited singlet, and is not particularly limited as long as light emission from the excited singlet is observed.

  Examples of the fluorescent dopant according to the present invention include anthracene derivatives, pyrene derivatives, chrysene derivatives, fluoranthene derivatives, perylene derivatives, fluorene derivatives, arylacetylene derivatives, styrylarylene derivatives, styrylamine derivatives, arylamine derivatives, boron complexes, coumarin derivatives. , Pyran derivatives, cyanine derivatives, croconium derivatives, squalium derivatives, oxobenzanthracene derivatives, fluorescein derivatives, rhodamine derivatives, pyrylium derivatives, perylene derivatives, polythiophene derivatives, rare earth complex compounds, and the like.

  In recent years, light emitting dopants utilizing delayed fluorescence have been developed, and these may be used.

  Specific examples of the luminescent dopant using delayed fluorescence include, for example, the compounds described in International Publication No. 2011/156793, Japanese Patent Application Laid-Open No. 2011-213643, Japanese Patent Application Laid-Open No. 2010-93181, and the like. Is not limited to these.

(1.2) Phosphorescence Emission Dopant The phosphorescence emission dopant according to the present invention (hereinafter also referred to as “phosphorescence dopant”) 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. It is an energy transfer type to obtain light emission from a phosphorescent dopant. The other is a carrier trap type in which a phosphorescent dopant serves as a carrier trap, and carrier recombination occurs on the phosphorescent dopant to emit light from the phosphorescent dopant. In any 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 dopant can be appropriately selected from known materials used for the light emitting layer of the organic EL device.

  Specific examples of known phosphorescent dopants that can be used in the present invention include compounds described in the following documents.

  Nature 395, 151 (1998), Appl. Phys. Lett. 78, 1622 (2001), Adv. Mater. 19, 739 (2007), Chern. Mater. 17, 3532 (2005), Adv. Mater. 17, 1059 (2005), International Publication No. 2009/100991, International Publication No. 200/8101842, International Publication No. 2003/040257, US Patent Publication No. 2006006835469, US Patent Publication No. 20060202194, US Patent Publication No. 20070087321. No., US Patent Publication No. 20050244673, Inorg. Chern. 40, 1704 (2001), Chern. Mater. 16, 2480 (2004), Adv. Mater. 16, 2003 (2004), Angew. Chern. lnt. Ed. 2006, 45, 7800, Appl. Phys. Lett. 86, 153505 (2005), Chern. Lett. 34, 592 (2005), Chern. Commun. 2906 (2005), Inorg. Chern. 42, 1248 (2003), International Publication No. 2009/050290, International Publication No. 2002/015645, International Publication No. 2009/000673, US Patent Publication No. 20020034656, US Pat. No. 7,332,232, US Publication No. 20090108737. US Patent Publication No. 20090039776, US Patent No. 6921915, US Patent No. 6,687,266, US Patent Publication No. 20070190359, US Patent Publication No. 2006060008670, US Patent Publication No. 20090165846, US Patent Publication No. 20080015355, US Patent No. 7250226, U.S. Pat. No. 7,396,598, U.S. Patent Publication No. 20060263635, U.S. Patent Publication No. 200301368657, U.S. Patent Publication No. 20030152. 02, U.S. Patent No. 7090928, Angew. Chern. lnt. Ed. 47, 1 (2008), Chern. Mater. 18, 5119 (2006), Inorg. Chern. 46, 4308 (2007), Organometallics 23, 3745 (2004), Appl. Phys. Lett. 74, 1361 (1999), International Publication No. 2002/002714, International Publication No. 2006/009024, International Publication No. 2006/056418, International Publication No. 2005/019373, International Publication No. 2005/123873, International Publication No. 2005/123873, International Publication No. 2007/004380, International Publication No. 2006/082742, U.S. Publication No. 20060251923, U.S. Publication No. 20050260441, U.S. Pat. No. 7,393,599, U.S. Pat. No. 7,534,505, U.S. Pat. No. 7445855, U.S. Patent Publication No. 20070190359, U.S. Patent Publication No. 200802977033, U.S. Pat. No. 7,338,722, U.S. Pat. Publication No. 20020134984, U.S. Pat. No. 7,279,704, U.S. Patent Publication 2006098120, US Patent Publication No. 2006103874, International Publication No. 2005/076380, International Publication No. 2010/032663, International Publication No. 2008/140115, International Publication No. 2007052431, International Publication No. 2011134013, International Publication No. 2011/157339, International Publication No. 2010/086089, International Publication No. 2009/113646, International Publication No. 2012/020327, International Publication No. 2011/051404, International Publication No. 2011/004639, Japanese Patent Application Laid-Open No. 2012-004639. No. 069737, Japanese Patent Application No. 2011-181303, Japanese Unexamined Patent Application Publication No. 2009-114086, Japanese Unexamined Patent Application Publication No. 2003-81988, Japanese Unexamined Patent Application Publication No. 2002-302671, Japanese Unexamined Patent Application Publication No. 2002-363552, and the like.

  Among these, a preferable phosphorescent dopant includes an organometallic complex having Ir as a central metal. More preferably, a complex containing at least one coordination mode of a metal-carbon bond, a metal-nitrogen bond, a metal-oxygen bond, or a metal-sulfur bond is preferable.

(2) Host compound The host compound according to the present invention is a compound mainly responsible for charge injection and transport in the light-emitting layer, and its own light emission is not substantially observed in the organic EL device.

  Preferably, it is a compound having a phosphorescence quantum yield of phosphorescence emission of less than 0.1 at room temperature (25 ° C.), more preferably a compound having a phosphorescence quantum yield of 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.

  Moreover, it is preferable that the excited state energy of a host compound is higher than the excited state energy of the light emission dopant contained in the same layer.

  A host compound may be used independently or may be used in combination of multiple types. 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.

  There is no restriction | limiting in particular as a host compound which can be used by this invention, The compound conventionally used with an organic EL element can be used. It may be a low molecular compound or a high molecular compound having a repeating unit, or a compound having a reactive group such as a vinyl group or an epoxy group.

  As known host compounds, while having a hole transporting ability or an electron transporting ability, the emission of light is prevented from being increased in wavelength, and further, the organic EL element is stable against heat generation during high temperature driving or driving of the element. From the viewpoint of operating, it is preferable to have a high glass transition temperature (Tg). Tg is preferably 90 ° C. or higher, more preferably 120 ° C. or higher.

  Here, the glass transition point (Tg) is a value obtained by a method based on JIS-K-7121 using DSC (Differential Scanning Colorimetry).

  Specific examples of known host compounds used in the organic EL device of the present invention include compounds described in the following documents, but the present invention is not limited thereto.

  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.

《Electron transport layer》
In the present invention, the electron transport layer is made of a material having a function of transporting electrons, and may have a function of transmitting electrons injected from the cathode to the light emitting layer.

  Although there is no restriction | limiting in particular about the total layer thickness of the electron carrying layer of this invention, Usually, it is the range of 2 nm-5 micrometers, More preferably, it is 2-500 nm, More preferably, it is 5-200 nm.

  Further, in the organic EL element, when the light generated in the light emitting layer is extracted from the electrode, the light extracted directly from the light emitting layer interferes with the light extracted after being reflected by the electrode from which the light is extracted and the electrode located at the counter electrode. It is known to wake up. When light is reflected by the cathode, this interference effect can be efficiently utilized by appropriately adjusting the total thickness of the electron transport layer between several nanometers and several micrometers.

On the other hand, when the layer thickness of the electron transport layer is increased, the voltage is likely to increase. Therefore, particularly when the layer thickness is thick, the electron mobility of the electron transport layer is preferably 10 ⁻⁵ cm ² / Vs or more. .

  The material used for the electron transport layer (hereinafter referred to as an electron transport material) may be any of electron injecting or transporting properties and hole blocking properties, and can be selected from conventionally known compounds. Can be selected and used.

  For example, a nitrogen-containing aromatic heterocyclic derivative (carbazole derivative, azacarbazole derivative (one or more of carbon atoms constituting the carbazole ring is substituted with a nitrogen atom), pyridine derivative, pyrimidine derivative, pyrazine derivative, pyridazine derivative, Triazine derivatives, quinoline derivatives, quinoxaline derivatives, phenanthroline derivatives, azatriphenylene derivatives, oxazole derivatives, thiazole derivatives, oxadiazole derivatives, thiadiazole derivatives, triazole derivatives, benzimidazole derivatives, benzoxazole derivatives, benzthiazole derivatives, etc.), dibenzofuran derivatives, And dibenzothiophene derivatives, silole derivatives, aromatic hydrocarbon ring derivatives (naphthalene derivatives, anthracene derivatives, triphenylene, etc.).

  In addition, a metal complex having a quinolinol skeleton or a dibenzoquinolinol skeleton as a ligand, for example, tris (8-quinolinol) aluminum (Alq), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7- Dibromo-8-quinolinol) aluminum, tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq) and the like, and their metal complexes A metal complex in which the central metal is replaced with In, Mg, Cu, Ca, Sn, Ga, or Pb can also be used as the electron transport material.

  In addition, metal-free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transporting material. In addition, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as an electron transport material, and an inorganic semiconductor such as n-type-Si, n-type-SiC, etc. as in the case of the hole injection layer and the hole transport layer. Can also be used as an electron transporting material.

  Further, 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 the electron transport layer according to the present invention, the electron transport layer may be doped with a doping material as a guest material to form an electron transport layer having a high n property (electron rich). Examples of the doping material include n-type dopants such as metal complexes and metal compounds such as metal halides. Specific examples of the electron transport layer having such a structure include, for example, JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, 2001-102175, J. Pat. Appl. Phys. , 95, 5773 (2004) and the like.

  Specific examples of known preferable electron transport materials used in the organic EL device of the present invention include compounds described in the following documents, but the present invention is not limited thereto.

  U.S. Pat.No. 6,528,187, U.S. Pat.No. 7,230,107, U.S. Patent Publication No. 20050025993, U.S. Pat. Publication No. 2004036077, U.S. Pat. Publication No. 200901115316, U.S. Pat. 2003060609, International Publication No. 2008/132805, Appl. Phys. Lett. 75, 4 (1999), Appl. Phys. Lett. 79, 449 (2001), Appl. Phys. Lett. 81, 162 (2002), Appl. Phys. Lett. 81, 162 (2002), Appl. Phys. Lett. 79, 156 (2001), U.S. Patent No. 7964293, U.S. Patent Publication No. 2009030202, International Publication No. 2004/080975, International Publication No. 2004/063159, International Publication No. 2005/085387, International Publication No. 2006/067931. No., International Publication No. 2007/085652, International Publication No. 2008/114690, International Publication No. 2009/069442, International Publication No. 2009066779, International Publication No. 200905253, International Publication No. 2011/088695, International Publication No. 2010 / 150593, International Publication No. 2010/047707, EP23111826, JP2010-251675A, JP2009-209133A, JP2009-124114A, JP2008-2778A. No. 0, JP-A No. 2006-156445, JP-A No. 2005-340122, JP-A No. 2003-45662, JP-A No. 2003-31367, JP-A No. 2003-282270, International Publication No. 2012/115034. No., etc.

  More preferable electron transport materials in the present invention include pyridine derivatives, pyrimidine derivatives, pyrazine derivatives, triazine derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, carbazole derivatives, azacarbazole derivatives, and benzimidazole derivatives.

  The electron transport material may be used alone or in combination of two or more.

《Hole blocking layer》
The hole blocking layer is a layer having the function of an electron transport layer in a broad sense, and is preferably made of a material having a function of transporting electrons and a small ability to transport holes. By blocking the holes, the probability of recombination of electrons and holes can be improved.

  Moreover, the structure of the electron carrying layer mentioned above can be used as a hole-blocking layer concerning this invention as needed.

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

  The layer thickness of the hole blocking layer according to the present invention is preferably in the range of 3 to 100 nm, more preferably in the range of 5 to 30 nm.

  As the material used for the hole blocking layer, the material used for the above-described electron transport layer is preferably used, and the material used as the above-described host compound is also preferably used for the hole blocking layer.

《Electron injection layer》
The electron injection layer (also referred to as “cathode buffer layer”) according to the present invention is a layer provided between the cathode and the light emitting layer in order to lower the driving voltage and improve the light emission luminance. It is described in detail in Chapter 2 “Electrode Materials” (pages 123 to 166) of the second edition of “The Forefront of Industrialization” (issued by NTT Corporation on November 30, 1998).

  In the present invention, the electron injection layer may be provided as necessary, and may be present between the cathode and the light emitting layer or between the cathode and the electron transport layer as described above.

  The electron injection layer is preferably a very thin film, and the layer thickness is preferably in the range of 0.1 to 5 nm, although it depends on the material. Moreover, the nonuniform film | membrane in which a constituent material exists intermittently may be sufficient.

  The details of the electron injection layer are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Specific examples of materials preferably used for the electron injection layer are as follows. , Metals typified by strontium and aluminum, alkali metal compounds typified by lithium fluoride, sodium fluoride, potassium fluoride, etc., alkaline earth metal compounds typified by magnesium fluoride, calcium fluoride, etc., oxidation Examples thereof include metal oxides typified by aluminum, metal complexes typified by lithium 8-hydroxyquinolate (Liq), and the like. Further, the above-described electron transport material can also be used.

  Moreover, the material used for said electron injection layer may be used independently, and may be used in combination of multiple types.

《Hole transport layer》
In the present invention, the hole transport layer is made of a material having a function of transporting holes and may have a function of transmitting holes injected from the anode to the light emitting layer.

  Although there is no restriction | limiting in particular about the total layer thickness of the positive hole transport layer of this invention, Usually, it is the range of 5 nm-5 micrometers, More preferably, it is 2-500 nm, More preferably, it is 5-200 nm.

  As a material used for the hole transport layer (hereinafter referred to as a hole transport material), any material that has either a hole injection property or a transport property or an electron barrier property may be used. Any one can be selected and used.

  For example, porphyrin derivatives, phthalocyanine derivatives, oxazole derivatives, oxadiazole derivatives, triazole derivatives, imidazole derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, hydrazone derivatives, stilbene derivatives, polyarylalkane derivatives, triarylamine derivatives, carbazole derivatives , Indolocarbazole derivatives, isoindole derivatives, acene derivatives such as anthracene and naphthalene, fluorene derivatives, fluorenone derivatives, and polyvinyl carbazole, polymer materials or oligomers with aromatic amines introduced into the main chain or side chain, polysilane, conductive And polymer (for example, PEDOT: PSS, aniline copolymer, polyaniline, polythiophene, etc.).

  Examples of the triarylamine derivative include a benzidine type typified by αNPD, a starburst type typified by MTDATA, and a compound having fluorene or anthracene in the triarylamine linking core part.

  In addition, hexaazatriphenylene derivatives such as those described in JP-A-2003-519432 and JP-A-2006-135145 can also be used as a hole transport material.

  Furthermore, a hole transport layer having a high p property doped with impurities can also 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.

  JP-A-11-251067, J. Org. Huang et. al. It is also possible to use so-called p-type hole transport materials and inorganic compounds such as p-type-Si and p-type-SiC as described in the literature (Applied Physics Letters 80 (2002), p. 139). Further, ortho-metalated organometallic complexes having Ir or Pt as the central metal represented by Ir (ppy) 3 are also preferably used.

  Although the above-mentioned materials can be used as the hole transport material, a triarylamine derivative, a carbazole derivative, an indolocarbazole derivative, an azatriphenylene derivative, an organometallic complex, or an aromatic amine is introduced into the main chain or side chain. The polymer materials or oligomers used are preferably used.

  Specific examples of known preferred hole transport materials used in the organic EL device of the present invention include the compounds described in the following documents in addition to the documents listed above, but the present invention is not limited thereto. Not.

  For example, Appl. Phys. Lett. 69, 2160 (1996), J. MoI. Lumin. 72-74, 985 (1997), Appl. Phys. Lett. 78, 673 (2001), Appl. Phys. Lett. 90, 183503 (2007), Appl. Phys. Lett. 90, 183503 (2007), Appl. Phys. Lett. 51, 913 (1987), Synth. Met. 87, 171 (1997), Synth. Met. 91, 209 (1997), Synth. Met. 111, 421 (2000), SID Symposium Digest, 37, 923 (2006), J. Am. Mater. Chern. 3, 319 (1993), Adv. Mater. 6, 677 (1994), Chern. Mater. 15, 3148 (2003), U.S. Patent Publication No. 20030162053, U.S. Patent Publication No. 200201558242, U.S. Patent Publication No. 20060240279, U.S. Patent Publication No. 20080220265, U.S. Patent No. 5061569, International Publication No. 2007/002683, International Publication Number Publication No. 2009/018009, EP650955, U.S. Patent Publication No. 20080124572, U.S. Publication No. 200707078938, U.S. Publication No. 20080106190, U.S. Publication No. 20080018221, International Publication No. 2012/115034, Special Table 2003-519432 No. 2006-135145, US Patent Application No. 13/585981, and the like.

  The hole transport material may be used alone or in combination of two or more.

《Electron blocking layer》
In a broad sense, the electron blocking layer is a layer having a function of a hole transport layer, and is preferably made of a material having a function of transporting holes and a small ability to transport electrons and transporting holes. However, the probability of recombination of electrons and holes can be improved by blocking electrons.

  Moreover, the structure of the positive hole transport layer mentioned above can be used as an electron blocking layer according to the present invention, if necessary.

  The electron blocking layer provided in the organic EL device of the present invention is preferably provided adjacent to the anode side of the light emitting layer.

  The layer thickness of the electron blocking layer according to the present invention is preferably in the range of 3 to 100 nm, more preferably in the range of 5 to 30 nm.

  As the material used for the electron blocking layer, the material used for the above-described hole transport layer is preferably used, and the material used as the above-described host compound is also preferably used for the electron blocking layer.

《Hole injection layer》
The hole injection layer (also referred to as “anode buffer layer”) according to the present invention is a layer provided between the anode and the light emitting layer in order to lower the driving voltage and improve the light emission luminance. 2 and Chapter 2 “Electrode Materials” (pages 123 to 166) of the 2nd edition of “The Forefront of Industrialization” (issued by NTT Corporation on November 30, 1998).

  In the present invention, the hole injection layer may be provided as necessary, and may be present between the anode and the light emitting layer or between the anode and the hole transport layer as described above.

  The details of the hole injection layer are also described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069, etc. Examples of the material used for the hole injection layer include: Examples thereof include materials used for the above-described hole transport layer.

  Among them, phthalocyanine derivatives typified by copper phthalocyanine, hexaazatriphenylene derivatives as described in JP-T-2003-519432, JP-A-2006-135145, etc., metal oxides typified by vanadium oxide, amorphous carbon, polyaniline (emeral Din) and conductive polymers such as polythiophene, orthometalated complexes represented by tris (2-phenylpyridine) iridium complex, and triarylamine derivatives are preferred.

  The materials used for the hole injection layer described above may be used alone or in combination of two or more.

"Additive"
The organic layer in the present invention described above may further contain other additives.

  Examples of the additive include halogen elements and halogenated compounds such as bromine, iodine and chlorine, alkali metals and alkaline earth metals such as Pd, Ca, and Na, transition metal compounds, complexes, and salts.

  The content of the additive can be arbitrarily determined, but is preferably 1000 ppm or less, more preferably 500 ppm or less, and further preferably 50 ppm or less with respect to the total mass% of the layer to be added. .

  However, it is not within this range depending on the purpose of improving the transportability of electrons and holes or the purpose of favoring the exciton energy transfer.

<Method for forming organic layer>
A method for forming the organic layer (hole injection layer, hole transport layer, light emitting layer, hole blocking layer, electron transport layer, electron injection layer, etc.) of the present invention will be described.

  The method for forming the organic layer of the present invention is not particularly limited, and a conventionally known method such as a vacuum deposition method or a wet method (also referred to as a wet process) can be used.

  Examples of the wet method include spin coating, casting, ink jet, printing, die coating, blade coating, roll coating, spray coating, curtain coating, and LB (Langmuir-Blodgett). From the viewpoint of obtaining a homogeneous thin film easily and high productivity, a method with high roll-to-roll method suitability such as a die coating method, a roll coating method, an ink jet method and a spray coating method is preferable.

  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 DMF and DMSO can be used.

  Moreover, as a dispersion method, it can disperse | distribute by dispersion methods, such as an ultrasonic wave, high shear force dispersion | distribution, and media dispersion | distribution.

Further, different film forming methods may be applied for each layer. When employing a vapor deposition method for film formation, the vapor deposition conditions vary depending on the type of compound used, but generally a boat heating temperature of 50 to 450 ° C., a degree of vacuum of 10 ⁻⁶ to 10 ⁻² Pa, and a vapor deposition rate of 0.01 to It is desirable to select appropriately within a range of 50 nm / second, a substrate temperature of −50 to 300 ° C., and a layer thickness of 0.1 nm to 5 μm, preferably 5 to 200 nm.

  The organic layer of the present invention is preferably formed from the hole injection layer to the cathode consistently by a single evacuation, but may be taken out halfway and subjected to different film forming methods. In that case, it is preferable to perform the work in a dry inert gas atmosphere.

"anode"
As the anode in the organic EL element, those having a work function (4 eV or more, preferably 4.5 V or more) of a metal, an alloy, an electrically conductive compound and a mixture thereof as an electrode material are 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 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.

  The layer thickness of the anode depends on the material, but is usually selected in the range of 10 nm to 1 μm, preferably 10 to 200 nm.

"cathode"
As the cathode, a material having a 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, aluminum, 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.

  In addition, a transparent or translucent cathode can be produced by producing a conductive transparent material mentioned in the description of the anode on the cathode after producing the metal with a layer thickness of 1 nm to 20 nm. By applying the above, it is possible to manufacture a device in which both the anode and the cathode are transparent.

《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. 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 (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 1 × 10 ⁻² g / (m ² · 24 h) or less barrier film, and further measured by a method based on JIS K 7126-1987. A high barrier film having an oxygen permeability of 1 × 10 ⁻³ cm ³ / (m ² · 24 h · atm) or less and a water vapor permeability of 1 × 10 ⁻⁵ g / (m ² · 24 h) or less. Preferably there is.

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

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

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

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

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

<Sealing>
Examples of the sealing means used for sealing the organic EL element of the present invention include a method of bonding a sealing member, an electrode, and a support substrate with an adhesive. 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 it may be concave plate shape or flat plate shape. Moreover, 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 organic EL element can be thinned. Further, the polymer film was measured by the method of oxygen permeability measured by the method based on JIS K 7126-1987 is ^{1 × 10 -3 cm 3 / m} 2 / 24h or less, in conformity with JIS K 7129-1992 water vapor transmission rate (25 ± 0.5 ° C., relative humidity (90 ± 2)%) is preferably that of ^{1 × 10 -3 g / (m} 2 / 24h) 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 infiltration 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 method, sputtering method, reactive sputtering method, molecular beam epitaxy method, 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 can also be used. Moreover, a hygroscopic compound can also be enclosed inside.

  Examples of the hygroscopic compound include metal oxides (eg, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide), sulfates (eg, sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate). Etc.), metal halides (for example, calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide, etc.), perchloric acids (for example, 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 outside the sealing film or the sealing film on the side facing the support substrate with the organic layer interposed therebetween. In particular, when sealing is performed by the sealing film, the mechanical strength is not necessarily high, and thus it is preferable to provide such a protective film and a protective plate. As a material that can be used for this, the same glass plate, polymer plate / film, metal plate / film, etc. used for the sealing can be used, but the polymer film is light and thin. Is preferably used.

《Light extraction enhancement technology》
An organic EL element emits light inside a layer having a refractive index higher than that of air (within a refractive index of about 1.6 to 2.1), and is about 15% to 20% of light generated in the light emitting layer. It is generally said that it can only be taken out. 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 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 side surface of the device.

  As a technique for improving the light extraction efficiency, for example, a method of forming irregularities on the surface of the transparent substrate to prevent total reflection at the transparent substrate and the air interface (for example, US Pat. No. 4,774,435), A method for improving efficiency by providing light condensing property (for example, JP-A-63-314795), a method for forming a reflective surface on a side surface of an element (for example, JP-A-1-220394), a substrate, etc. A method of forming an antireflection film by introducing a flat layer having an intermediate refractive index between the substrate and the light emitter (for example, Japanese Patent Application Laid-Open No. 62-172691), lower refraction than the substrate between the substrate and the light emitter A method of introducing a flat layer having a refractive index (for example, Japanese Patent Application Laid-Open No. 2001-202827), and a method of forming a diffraction grating between any one of the substrate, the transparent electrode layer and the light emitting layer (including between the substrate and the outside world) ( JP-A-11 No. 283,751 Publication), and the like.

  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 low refractive index medium 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. Become. 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 in the range of about 1.5 to 1.7, the low refractive index layer preferably has a refractive index of about 1.5 or less. Furthermore, it is preferable that it is 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 exuded by evanescent enters the substrate.

  The method of introducing a diffraction grating into an interface that causes total reflection or in any medium has a feature that the effect of improving the light extraction efficiency is high. 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 or second-order diffraction. The light that cannot be emitted due to total internal reflection between layers is diffracted by introducing a diffraction grating into any layer or medium (in the transparent substrate or transparent electrode). , Trying to extract light 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. 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.

  The position where the diffraction grating is introduced may be in any of the layers or in the medium (in the transparent substrate or 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 within a range of about 1/2 to 3 times the wavelength of light in the medium. The arrangement of the diffraction gratings is preferably two-dimensionally repeated, such as a square lattice, a triangular lattice, or a honeycomb lattice.

《Condensing sheet》
The organic EL element of the present invention can be processed in such a way that a structure on a microlens array, for example, is provided on the light extraction side of a support substrate (substrate) or combined with a so-called condensing sheet, for example, in a specific direction Condensing light in the front direction with respect to the light emitting surface can increase the luminance in a specific direction.

  As an example of the microlens array, quadrangular pyramids having a side of 30 μm and an apex angle of 90 degrees are arranged two-dimensionally on the light extraction side of the substrate. One side is preferably within a range of 10 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, a substrate may be formed with a Δ-shaped stripe having an apex angle of 90 degrees and a pitch of 50 μm, or the apex angle is rounded and the pitch is changed randomly. Other shapes may also be used.

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

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

  In the organic EL 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.

<Display device>
The display device of the present invention will be described. The display device of the present invention comprises the organic EL element of the present invention.

  Although the display device of the present invention may be single color or multicolor, the multicolor display device will be described here. In the case of a multicolor display device, a shadow mask is provided only at the time of forming a light emitting layer, and a film can be formed on one surface by vapor deposition, casting, spin coating, ink jet, printing, or the like.

  In the case of patterning only the light emitting layer, the method is not limited, but preferably the vapor deposition method, the ink jet method, the spin coating method, and the printing method.

  The configuration of the organic EL element provided in the display device is selected from the above-described configuration examples of the organic EL element as necessary.

  Moreover, the manufacturing method of an organic EL element is as having shown to the one aspect | mode of manufacture of the organic EL element of said invention.

  In the case of applying a DC voltage to the obtained multicolor display device, light emission can be observed by applying a voltage of about 2V to 40V with the positive polarity of the anode and the negative polarity of the cathode. Further, even when a voltage is applied with the opposite polarity, no current flows and no light emission occurs. Further, when an AC voltage is applied, light is emitted only when the anode is in the + state and the cathode is in the-state. The alternating current waveform to be applied may be arbitrary.

  The multicolor display device can be used as a display device, a display, and various light emission sources. In a display device or display, full-color display is possible by using three types of organic EL elements of blue, red, and green light emission.

  Examples of the display device and display include a television, a personal computer, a mobile device, an AV device, a character broadcast display, and an information display in an automobile. In particular, it may be used as a display device for reproducing still images and moving images, and the driving method when used as a display device for reproducing moving images may be either a simple matrix (passive matrix) method or an active matrix method.

  Light emitting 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, light sources for optical sensors, etc. However, the present invention is not limited to these.

  Hereinafter, an example of a display device having the organic EL element of the present invention will be described with reference to the drawings.

  FIG. 2 is a schematic view showing an example of a display device composed of organic EL elements. It is a schematic diagram of a display such as a mobile phone that displays image information by light emission of an organic EL element.

  The display 1 includes a display unit A having a plurality of pixels, a control unit B that performs image scanning of the display unit A based on image information, and the like.

  The control unit B is electrically connected to the display unit A, and sends a scanning signal and an image data signal to each of the plurality of pixels based on image information from the outside. The pixels for each scanning line are converted into image data signals by the scanning signal. In response to this, light is sequentially emitted and image scanning is performed to display image information on the display unit A.

  FIG. 3 is a schematic diagram of the display unit A.

  The display unit A includes a wiring unit including a plurality of scanning lines 5 and data lines 6, a plurality of pixels 3 and the like on a substrate. The main members of the display unit A will be described below.

  In the figure, the light emitted from the pixel 3 is extracted in the direction of the white arrow (downward).

  The scanning lines 5 and the plurality of data lines 6 in the wiring portion are each made of a conductive material, and the scanning lines 5 and the data lines 6 are orthogonal to each other in a lattice shape and are connected to the pixels 3 at the orthogonal positions (details are shown in FIG. Not shown).

  When a scanning signal is applied from the scanning line 5, the pixel 3 receives an image data signal from the data line 6 and emits light according to the received image data.

  Full-color display is possible by appropriately arranging pixels in the red region, the green region, and the blue region on the same substrate.

  Next, the light emission process of the pixel will be described.

  FIG. 4 is a schematic diagram of a circuit.

  The pixel includes an organic EL element 10, a switching transistor 11, a driving transistor 12, a capacitor 13, and the like. A full color display can be performed by using red, green, and blue light emitting organic EL elements as the organic EL elements 10 in a plurality of pixels, and juxtaposing them on the same substrate.

  In FIG. 4, an image data signal is applied from the control unit B to the drain of the switching transistor 11 through the data line 6. When a scanning signal is applied from the control unit B to the gate of the switching transistor 11 via the scanning line 5, the driving of the switching transistor 11 is turned on, and the image data signal applied to the drain is supplied to the capacitor 13 and the driving transistor 12. Is transmitted to the gate.

  By transmitting the image data signal, the capacitor 13 is charged according to the potential of the image data signal, and the drive of the drive transistor 12 is turned on. The drive transistor 12 has a drain connected to the power supply line 7 and a source connected to the electrode of the organic EL element 10, and the power supply line 7 connects to the organic EL element 10 according to the potential of the image data signal applied to the gate. Current is supplied.

  When the scanning signal is moved to the next scanning line 5 by the sequential scanning of the control unit B, the driving of the switching transistor 11 is turned off. However, since the capacitor 13 holds the charged potential of the image data signal even if the driving of the switching transistor 11 is turned off, the driving of the driving transistor 12 is kept on and the next scanning signal is applied. Until then, the light emission of the organic EL element 10 continues. When the scanning signal is next applied by sequential scanning, the driving transistor 12 is driven according to the potential of the next image data signal synchronized with the scanning signal, and the organic EL element 10 emits light.

  That is, the light emission of the organic EL element 10 is performed by providing the switching transistor 11 and the drive transistor 12 which are active elements with respect to the organic EL element 10 of each of the plurality of pixels, and the light emission of the organic EL element 10 of each of the plurality of pixels 3. It is carried out. Such a light emitting method is called an active matrix method.

  Here, the light emission of the organic EL element 10 may be light emission of a plurality of gradations by a multi-value image data signal having a plurality of gradation potentials, or on / off of a predetermined light emission amount by a binary image data signal. But you can. The potential of the capacitor 13 may be held continuously until the next scanning signal is applied, or may be discharged immediately before the next scanning signal is applied.

  In the present invention, not only the active matrix method described above, but also a passive matrix light emission drive in which the organic EL element emits light according to the data signal only when the scanning signal is scanned.

  FIG. 5 is a schematic diagram of a passive matrix display device. In FIG. 5, a plurality of scanning lines 5 and a plurality of image data lines 6 are provided in a lattice shape so as to face each other with the pixel 3 interposed therebetween.

  When the scanning signal of the scanning line 5 is applied by sequential scanning, the pixels 3 connected to the applied scanning line 5 emit light according to the image data signal.

  In the passive matrix system, the pixel 3 has no active element, and the manufacturing cost can be reduced.

《Lighting device》
The lighting device of the present invention will be described. The illuminating device of this invention has the said organic EL element.

  The organic EL element of the present invention may be used as an organic EL element having a resonator structure. The purpose of use of the organic EL element having such a resonator structure is as follows. The light source of a machine, the light source of an optical communication processing machine, the light source of a photosensor, etc. are mentioned, However It is not limited to these. Moreover, you may use for the said use by making a laser oscillation.

  Further, the organic EL element of the present invention may be used as a kind of lamp for illumination or exposure light source, a projection device for projecting an image, or a display for directly viewing a still image or a moving image. It may be used as a device (display).

  The driving method when used as a display device for moving image reproduction may be either a simple matrix (passive matrix) method or an active matrix method. Alternatively, it is possible to produce a full-color display device by using two or more organic EL elements of the present invention having different emission colors.

  The organic EL material of the present invention can be applied to an organic EL element that emits substantially white light as a lighting device. A plurality of light emitting colors are simultaneously emitted by a plurality of light emitting materials to obtain white light emission by color mixing. The combination of a plurality of emission colors may include three emission maximum wavelengths of the three primary colors of blue, green, and blue, or two using the relationship of complementary colors such as blue and yellow, blue green and orange, etc. The thing containing the light emission maximum wavelength may be used.

  In addition, a combination of light emitting materials for obtaining a plurality of emission colors is a combination of a plurality of phosphorescent or fluorescent materials, a light emitting material that emits fluorescence or phosphorescence, and light from the light emitting material as excitation light. Any of those combined with a dye material that emits light may be used, but in the white organic EL device according to the present invention, only a combination of a plurality of light-emitting dopants may be mixed.

  It is only necessary to provide a mask only when forming a light emitting layer, a hole transport layer, an electron transport layer, etc., and simply arrange them separately by coating with the mask. Since other layers are common, patterning of the mask or the like is not necessary. In addition, for example, an electrode film can be formed by a vapor deposition method, a cast method, a spin coating method, an ink jet method, a printing method, or the like, and productivity is also improved.

  According to this method, unlike a white organic EL device in which light emitting elements of a plurality of colors are arranged in parallel in an array, the elements themselves are luminescent white.

  The light emitting material used for the light emitting layer is not particularly limited. For example, in the case of a backlight in a liquid crystal display element, the metal complex according to the present invention is adapted so as to conform to a wavelength range corresponding to CF (color filter) characteristics. Moreover, what is necessary is just to select and combine arbitrary things from well-known luminescent materials, and to whiten.

<< One Embodiment of Lighting Device of the Present Invention >>
One aspect of the lighting device of the present invention that includes the organic EL element of the present invention will be described.

  The non-light emitting surface of the organic EL device of the present invention is covered with a glass case, a 300 μm thick glass substrate is used as a sealing substrate, and an epoxy photocurable adhesive (LUX The track LC0629B) is applied, and this is overlaid on the cathode and brought into close contact with the transparent support substrate, irradiated with UV light from the glass substrate side, cured, sealed, and illuminated as shown in FIGS. A device can be formed.

  FIG. 6 shows a schematic diagram of the lighting device, and the organic EL element 101 of the present invention is covered with a glass cover 102 (in the sealing operation with the glass cover, the organic EL element 101 is brought into contact with the atmosphere. And a glove box under a nitrogen atmosphere (in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more).

  FIG. 7 is a cross-sectional view of the lighting device. In FIG. 7, reference numeral 105 denotes a cathode, 106 denotes an organic EL layer, and 107 denotes a glass substrate with a transparent electrode. The glass cover 102 is filled with nitrogen gas 108 and a water catching agent 109 is provided.

  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.

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

[Example 1]
<< Manufacture of organic nanocrystal particles >>
The organic nanocrystal particle dispersion was synthesized as follows. In addition, about manufacture of organic nanocrystal particle | grains, it can manufacture using the well-known nanocrystal particle | grain synthesis method using the micro mixer (reactor) as described in international publication 05/023704 grade | etc.,.

<Manufacture of HT-1 nanocrystal particle dispersion>
A 1% chlorobenzene solution of poly [N, N′-bis (4-butylphenyl) -N, N′-diphenylbenzidine] (American Dye Source, ADS-254) (HT-1) was prepared, It set to the liquid pump 4003 type made from AQUATH. Next, tetrahydrofuran (THF), which is compatible with chlorobenzene and is a poor solvent for HT-1, was set in a liquid pump 4060 manufactured by AQUATH. Two pumps were connected by a Y-shaped joint. The two pumps started feeding at a flow rate of 0.03 ml / min for the 4003 type and 29.7 ml / min for the 4060 type, respectively. The mixed solvent which flowed out was collect | recovered, and when it confirmed with the scanning electron microscope (SEM) as follows, it was the organic nanocrystal particle | grains which have a particle size of 20-70 nm (average particle diameter of 50 nm).

<Measurement of average particle size>
In the following examples, the average measurement method of nanocrystal particles was calculated from a scanning electron microscope (photograph image observed and photographed by SEM. Photographing was performed by setting the magnification of the microscope to 10,000 times. Calculated by extracting nanocrystal particles randomly from the image, specifically, by observing 100 or more nanocrystal particles randomly from the electron microscope observation of the nanocrystal particles, and obtaining the particle size of each nanocrystal particle. The average particle diameter was obtained by obtaining the number average value, and when the shape of the nanocrystal particles was not spherical, the one obtained by measuring the major axis was used.

  It was also confirmed that classification and concentration were possible using a centrifuge. Concentration can be achieved by means such as evaporation by heat or running under reduced pressure. However, when the boiling point of the good solvent for the organic matter forming the nanocrystal particles is higher than that for the poor solvent, the formed nanocrystal particles Care must be taken because the particle size may increase due to redissolution or particle growth.

<Production 1 of mCP: Ir-B Composite Nanocrystal Particle Dispersion>
After weighing mCP and Ir-B so as to have a mass ratio of 100: 20, a 1% toluene solution was prepared. This was set in a liquid pump 4003 manufactured by AQUATH. Next, hexane, which is compatible with toluene and is a poor solvent for mCP and Ir-B, was set in the other 4060 type pump. When nanocrystal particles were produced in the same manner as in HT-1, organic nanocrystal particles in which a host compound having a particle size of 30 to 60 nm (average particle size of 45 nm) and a light-emitting dopant were combined were confirmed.

<Manufacture 2 of mCP: Ir-B composite nanocrystal particle dispersion>
To synthesize composite nanocrystal particles composed of a plurality of mixtures, a plurality of materials are made into a uniform solution as described above, and then nanocrystal particles are formed between any of the plurality of materials and a solvent that is a poor solvent. In addition to the method, first, single nanocrystal particles can be synthesized and then combined with a uniform solution of this dispersion and other materials.

  For example, a 1% toluene solution of Ir-B was prepared. An Ir-B nanocrystal particle dispersion was obtained in exactly the same manner as in <Manufacture of mCP: Ir-B composite nanocrystal particle dispersion 1> except that this was set in a liquid pump 4003 manufactured by AQUATH. (The particle size is 20 to 50 nm, the average particle size is 35 nm) This dispersion is set in a liquid pump 4060 type manufactured by AQUATH, and the other 4003 type is set with a 1% toluene solution of mCP, and nanocrystals Particles were produced. As a result, SEM confirmed composite nanocrystal particles having a slightly large particle size of 40 to 70 nm. In the case of mCP: Ir-B composite nanocrystal particles, it was confirmed that classification and concentration were possible as in the case of HT-1.

  In addition, since the particle size of the nanocrystal particles can be controlled by the concentration, flow rate, and flow rate ratio, the size of the nanocrystal particles used as a seed and the size after compounding can be easily controlled by setting conditions. there were.

<Production 2 of ET-1 Nanocrystalline Particle Dispersion>
As in the case of HT-1, a 1% THF solution of ET-1 is prepared and set in a 4003 type pump, and hexane that is a poor solvent for ET-1 is set in the other 4060 type pump. -1 Production of Nanocrystalline Particle Dispersion> As a result, organic nanocrystal particles having a particle size of 50 to 70 nm (average particle size of 55 nm) were confirmed by SEM.

[Example 2]
<Production of single charge element>
As shown below, a single charge element that flows only holes for hole transport confirmation, so-called hole-only device; HOD), and a single charge element that flows only electrons for confirmation of electron transport property, so-called electron-only device; EOD) was produced.

<< Production of HOD-1 >>
Patterning was performed on a substrate (NA-45, manufactured by AvanStrate Co., Ltd.) in which ITO (Indium Tin Oxide) was formed to a thickness of 100 nm on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode. Thereafter, the transparent support substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  A thin film was formed on this substrate by spin coating using a 1.0% chlorobenzene solution of HT-1 as a hole transport material. A hole transport layer having a layer thickness of 40 nm was provided by heating and drying at 120 ° C. for 1 hour.

  Next, mCP and Ir-B were weighed on the hole transport layer in a ratio of 100: 20 to prepare a 1.0% isopropyl acetate solution. Using this solution, a thin film was formed by spin coating. Heat-dried at 80 degreeC for 1 hour, and provided the light emitting layer with a layer thickness of 40 nm.

  Similarly, a 1.0% hexafluoroisopropyl alcohol (HFIP) solution of ET-1 was prepared on the light emitting layer, and a thin film was formed by spin coating. It was dried by heating at 120 ° C. for 1 hour to provide an electron transport layer having a layer thickness of 40 nm.

The substrate on which the electron transport layer was formed was attached to a vacuum deposition apparatus. After depressurizing the vacuum chamber to 4 × 10 ⁻⁴ Pa, molybdenum oxide was deposited to a thickness of 10 nm as an electron blocking layer.

  Finally, a hole-only device HOD-1 was produced by depositing aluminum to form a cathode having a layer thickness of 110 nm.

<< Production of HOD-7 >>
In the same manner as in the production of HOD-1, patterning was performed on a substrate (NAV-45, manufactured by AvanStrate Co., Ltd.) on which a 100-nm-thick ITO film was formed on a 100 mm × 100 mm × 1.1 mm glass substrate. . Thereafter, the transparent support substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  On this substrate, a thin film was formed by spin coating using the HT-1 nanocrystal particle dispersion prepared by the above method as a hole transport material. A hole transport layer having a layer thickness of 40 nm was provided by heating and drying at 120 ° C. for 1 hour.

  Next, a thin film was formed on the hole transport layer by a spin coating method using the nanocrystal particle dispersion liquid prepared in <Preparation 1 of mCP: Ir-B composite nanocrystal particle dispersion liquid>. Heat-dried at 80 degreeC for 1 hour, and provided the light emitting layer with a layer thickness of 40 nm.

Similarly, a thin film was formed on the light emitting layer by spin coating using ET-1 nanocrystal particle dispersion. It was dried by heating at 120 ° C. for 1 hour to provide an electron transport layer having a layer thickness of 40 nm. The substrate on which the electron transport layer was formed was attached to a vacuum deposition apparatus. After depressurizing the vacuum chamber to 4 × 10 ⁻⁴ Pa, molybdenum oxide was deposited to a thickness of 10 nm as an electron blocking layer.

  Finally, aluminum was vapor-deposited to form a cathode having a layer thickness of 110 nm, thereby producing a single charge element HOD-1.

<< Production of HOD-2 to 6 and HOD-8 to 9 >>
For the production of HOD-2 to 6 and HOD-8 to 9, the hole transport layer, the light emitting layer, and the electron transport layer were made in the same manner as HOD-1 or HOD-7, and the materials shown in Table 2 and their production. It was produced by replacing with a film method (coating film formation of a solution or coating film formation of a nanocrystal particle dispersion).

<< Production of EOD-7 >>
Patterning was performed on a substrate (NA-45, manufactured by AvanStrate Co., Ltd.) in which ITO (Indium Tin Oxide) was formed to a thickness of 100 nm on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode. Thereafter, the transparent support substrate provided with the ITO transparent electrode 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 vacuum deposition apparatus. After depressurizing the vacuum chamber to 4 × 10 ⁻⁴ Pa, calcium was deposited as a hole blocking layer to a thickness of 5 nm. The substrate is taken out from the apparatus, and in a glove box under a nitrogen atmosphere, a hole transport layer, a light emitting layer, and an electron transport layer are formed by spin coating using a nanocrystal dispersion liquid, exactly as in the case of HOD-7. Was formed. Again, the substrate on which the electron transport layer was formed was attached to a vacuum deposition apparatus. After depressurizing the vacuum chamber to 4 × 10 ⁻⁴ Pa, aluminum was deposited to form a cathode having a layer thickness of 110 nm, thereby producing a single charge device EOD-7.

<< Production of EOD-1 to 6 and EOD-8 to 9 >>
For EOD-1 to 6 and EOD-8 to 9, the materials described in Table 2 were used, using the film formation method of the hole transport layer, the light emitting layer, and the electron transport layer by the respective solutions described in the preparation of HOD-1. It was produced by replacing it with the film forming method.

[Example 3]
<Evaluation of single charge device>
When evaluating the obtained single charge devices HOD-1 to HOD-9 and EOD-1 to EOD-9, the aluminum electrode side of each device after fabrication was covered with a glass case, and a glass substrate having a thickness of 300 μm was sealed. An epoxy-based photo-curing adhesive (Lux Track LC0629B manufactured by Toagosei Co., Ltd.) is applied as a sealing material to the periphery as a sealing substrate, and this is overlaid on the cathode and brought into close contact with the transparent support substrate. The substrate was irradiated with UV light, cured, sealed and evaluated.

(Current density)
About the produced single charge element, the current-voltage characteristic was measured. The current density was calculated from the current value when 5 V was applied. For the measurement, a 6430 type sub-femtoamper remote source meter manufactured by KEITHLEY was used. In the table, relative values with the current density of HOD-4 and EOD-4 of the device comparative example as 100 are shown.

  In the above evaluations of the single charge elements HOD-1 to HOD-9 and EOD-1 to EOD-9, no light emission was observed, and it was confirmed that evaluation related to single charge transfer was performed.

  As can be seen from Tables 3 and 4, not only the light emitting layer of the device example but also one of the adjacent layers contains the nanocrystalline particles, so that compared to the system using the nanocrystalline particles only in the light emitting layer. It is clear that the current density is improved for both holes, electrons. Moreover, when HOD-4, HOD-5, and HOD-8 are compared, when the adjacent layer of the layer containing nanocrystal particles is formed from a uniform solution of an organic material, a decrease in current density is observed. This suggests that the injection into the nanocrystal particles and the charge transfer between the nanocrystal particles are deeply involved in the electric field concentration, and the normal organic film (a film formed from a uniform solution or molecular deposition by evaporation etc.) In the case of (film), it is a result that a bonding failure occurs and charge transfer is impeded.

  On the other hand, when the adjacent layer of the layer containing nanocrystal particles is formed of an inorganic material such as a metal, a metal oxide, or a metal salt like HOD-8, the charge density of this layer is that of the organic layer. On the other hand, the relatively high value suggests that inhibition of charge transfer is reduced.

[Example 4]
<< Production of organic EL element >>
<< Preparation of organic EL element EL-5 >>
Patterning was performed on a substrate (NA-45, manufactured by AvanStrate Co., Ltd.) in which ITO (Indium Tin Oxide) was formed to a thickness of 100 nm on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode. Thereafter, the transparent support substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  A solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer Co., Ltd., Baytron P Al4083) to 70% with pure water on this transparent support substrate was used. After forming a thin film by the coating method, it was dried at 200 ° C. for 1 hour to provide a first hole transport layer having a layer thickness of 30 nm.

  On this substrate, a thin film was formed by spin coating using the HT-1 nanocrystal particle dispersion prepared by the above method as a hole transport material. A hole transport layer having a layer thickness of 40 nm was provided by heating and drying at 120 ° C. for 1 hour.

  Next, a thin film was formed on the hole transport layer by spin coating using the nanocrystal particle dispersion prepared in <Production 1 of <mCP: Ir-B composite nanocrystal particle dispersion >>. Heat-dried at 80 degreeC for 1 hour, and provided the light emitting layer with a layer thickness of 40 nm.

  Similarly, a thin film was formed on the light emitting layer by spin coating using ET-1 nanocrystal particle dispersion. It was dried by heating at 120 ° C. for 1 hour to provide an electron transport layer having a layer thickness of 40 nm.

The substrate on which the electron transport layer was formed was attached to a vacuum deposition apparatus. After depressurizing the vacuum chamber to 4 × 10 ⁻⁴ Pa, lithium fluoride (LiF) was deposited as a layer thickness of 1.0 nm as an electron injection layer. Finally, aluminum was vapor-deposited to form a cathode having a layer thickness of 110 nm, thereby fabricating an organic EL element EL-5.

<< Production of Organic EL Elements EL-1 to EL-4 and Organic EL Elements EL-6 to EL-9 >>
The organic EL elements EL-1 to EL-4 and the organic EL elements EL-6 to EL-9 were prepared in the same manner as EL-5 by substituting the materials described in Table 5 and their film forming methods. In the table, ITO represents Indium Tin Oxide (indium tin oxide), ZnO represents zinc oxide, and a nanocrystal particle dispersion containing no dispersion stabilizer was prepared according to a conventional method.

[Example 5]
<< Evaluation of organic EL elements >>
When evaluating the obtained organic EL elements EL-1 to EL-9, the non-light-emitting surface of each organic EL element after production was covered with a glass case, and a glass substrate having a thickness of 300 μm was used as a sealing substrate. In addition, an epoxy-based photo-curing adhesive (Lux Track LC0629B manufactured by Toagosei Co., Ltd.) is applied as a sealing material in the periphery, and this is placed on the cathode so as to adhere to the transparent support substrate, and UV light is emitted from the glass substrate side. Irradiation, curing and sealing were performed, and an illumination device as shown in FIGS. 6 and 7 was formed and evaluated.

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

(Luminescent life)
When driving at a constant current of ^2.5 mA / cm ^{2 in} a dry nitrogen gas atmosphere at 23 ° C., the time required for the luminance to drop to half of the luminance immediately after the start of light emission (initial luminance) was measured. Was used as an index of life as half-life time (τ0.5).

  For the measurement, a spectral radiance meter CS-1000 (manufactured by Konica Minolta Optics) was used in the same manner.

(Drive voltage)
The driving voltage of the device was measured when it was driven at a constant current of ^2.5 mA / cm ² at 23 ° C. in a dry nitrogen gas atmosphere.

(Film density)
The film density was measured by the X-ray reflectometry method.

  As the measuring apparatus, MXP21 manufactured by Mac Science Co., Ltd. was used, copper was used as the target of the X-ray source, and it was operated at 42 kV and 500 mA. A multilayer parabolic mirror was used for the incident monochromator. The entrance slit is 0.05 mm x 5 mm, the light receiving slit is 0.03 mm x 20 mm, and the 2θ / θ scan method is used to measure from 0 to 5 ° by the FT method with a step width of 0.005 ° and a step of 10 seconds. It was. With respect to the obtained reflectance curve, Reflectivity Analysis Program Ver. Curve fitting was performed using 1 to determine each parameter so that the residual sum of squares of the actual measurement value and the fitting curve was minimized, and the density of the laminated film was determined from each parameter. The results of the external extraction quantum efficiency, the light emission lifetime, the driving voltage, and the film density of the organic EL elements EL-1 to EL-9 were evaluated by relative evaluation with the organic EL element EL-1 (comparative example) as 100. The results obtained are shown in Table 6.

  As is apparent from Table 6, a significant drive voltage drop was observed in the configuration of the present invention, reflecting the evaluation results of the single charge device described above. In addition, since the electric field concentration is a large driving force for injection and transport, it is expected that the confinement effect of charges or excitons is expected to increase, and the result appears as an improvement in external extraction quantum efficiency.

  Also, from the result of transmission electron microscope (TEM) observation of the cross section of the element, it is clear that it is formed by close packing of spherical particles reflecting nanocrystal particles, which is clearly different from the film formed from a uniform solution. It was. This is reflected in the result of the film density by the XRD method, and is dense with respect to the film density formed from the uniform solution.

  This result is considered as follows. In a homogeneous solution, a large number of solvent molecules are solvating solute molecules, and a film is formed by desorption of the solvated molecules from the wet state over time (ie, this is the drying process). Is done. In the course of this change over time, the fluidity of the film is gradually lost, and the film density becomes relatively sparse.

  On the other hand, in the nanocrystal particle, the density of the crystal particle itself was high, and the number of solvated molecules was relatively small, and the energy of solvation was small, so that the film density was kept high.

  From the above results, since at least one of the layers adjacent to the layer containing nanocrystal particles is a layer containing nanocrystal particles, or a layer formed from an inorganic substance such as a metal, metal oxide, or metal salt, an organic EL element As shown in EL-9, organic nanocrystal particles are arranged in adjacent layers on both sides of a light-emitting layer containing nanocrystal particles, so that a hole injection layer and a three-layer structure in which an electron injection layer is shared (positive) Realization of high-performance (high efficiency, long life, low drive voltage) devices in the hole transport layer, light-emitting layer, and electron transport layer has become possible.

[Example 6]
<Production of full-color display device>
(Blue light emitting organic EL device)
The organic EL element EL-5 produced in Example 4 was used.

(Green light-emitting organic EL device)
In the production of the organic EL element EL-5 described in Example 4, EL-5G produced by replacing Ir-B used in the light emitting layer with Ir-G was used. The mCP: Ir-G composite nanocrystal particle dispersion used here is completely the same as <Production 1 of mCP: Ir-B composite nanocrystal particle dispersion> except that Ir-B used is changed to Ir-G. Prepared in the same manner.

(Red light emitting organic EL device)
In the production of the organic EL element EL-5 described in Example 4, EL-5R used in the light emitting layer, in which Ir-B was replaced with Ir-R, was used. The mCP: Ir-R composite nanocrystal particle dispersion used is completely the same as <Manufacture of mCP: Ir-B composite nanocrystal particle dispersion 1> except that Ir-B used is changed to Ir-R. Prepared in the same manner.

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

  It was confirmed that by driving the full-color display device, a full-color display with a low driving voltage, high luminous efficiency, and long emission lifetime can be obtained.

[Example 7]
<< Preparation of white light emitting organic EL element EL-5W >>
In the production of the organic EL device EL-5 described in Example 4, Ir-B used in the light emitting layer was replaced with a mixture of a composite nanocrystal particle dispersion of Ir-B, Tr-G and Ir-R. Organic EL element EL-5W was used. The mCP: Ir-B: Ir-G: Ir-R composite nanocrystal particle dispersion to be used is the same as the Ir-B mixture except that Ir-B is changed to an Ir-B, Tr-G, Ir-R mixture. mCP: Ir-B composite nanocrystal particle dispersion 1> Prepared in exactly the same manner. The produced organic EL element EL-5W emits light when energized, and the front luminance at a viewing angle of 2 degrees was measured with a spectral radiance meter CS-1000 (manufactured by Konica Minolta Optics). As a result, CIE1931 at 1000 cd / m ² was obtained. It was confirmed that white light was present in the region where the chromaticity in the color system was X = 0.33 ± 0.07 and Y = 0.33 ± 0.1. It was also confirmed that it was useful as a lighting device.

a atom or molecule constituting nanocrystal b atom or molecule constituting grain boundary 1 display 3 pixel 5 scanning line 6 data line 7 power line 10 organic EL element 11 switching transistor 12 drive transistor 13 capacitor A display unit B control unit 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 (9)

  An organic electroluminescence device having a light emitting layer and two charge transport layers adjacent to both sides of the light emitting layer between a cathode and an anode, wherein the light emitting layer and the two charge transport layers An organic electroluminescence device, wherein at least one of the layers contains nanocrystalline particles.   2. The organic electroluminescence device according to claim 1, wherein the charge transport layer on the cathode side adjacent to the light emitting layer contains the nanocrystal particles.   The organic electroluminescence device according to claim 1, wherein the charge transport layer on the anode side adjacent to the light emitting layer contains the nanocrystal particles.   The organic electroluminescence device according to any one of claims 1 to 3, wherein the nanocrystalline particles contained in the charge transport layer are organic nanocrystalline particles.   The organic electroluminescence device according to any one of claims 1 to 3, wherein the nanocrystalline particles contained in the charge transport layer are inorganic nanocrystalline particles.   6. The organic electroluminescence device according to claim 5, wherein the inorganic nanocrystal particles are metal, metal salt or metal oxide nanocrystal particles.   The organic electroluminescent element as described in any one of Claim 1- Claim 6 exhibits white light emission, The organic electroluminescent element characterized by the above-mentioned.   The organic electroluminescent element as described in any one of Claim 1- Claim 7 is comprised, The illuminating device characterized by the above-mentioned.   A display device comprising the organic electroluminescence element according to any one of claims 1 to 7.

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