JP2013100239A - Material for organic electroluminescent element, organic electroluminescent element, display device, and illumination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a material for an organic electroluminescent element.SOLUTION: The material for an organic electroluminescent element is represented by formula (1). In the formula (1), X is an oxygen atom, a sulfur atom, PR, PR(=Y) or SiRR; and at least one of Rto Ris represented by formula (2). In the formula (2), L is a group to which an arylene group or the like is bonded; and Y is an oxygen atom, a sulfur atom or the like.

Description

  The present invention relates to an organic electroluminescent element material, an organic electroluminescent element, a display device, and a lighting device, and more specifically, a material for an organic electroluminescent element excellent in luminous efficiency, luminous lifetime, and driving stability, and the same. The present invention relates to an organic electroluminescence element, a display device, and a lighting device used.

  Conventionally, as a light-emitting electronic display device, there is an electroluminescence display (hereinafter referred to as ELD). Examples of the constituent elements of ELD include inorganic electroluminescent elements and organic electroluminescent elements (hereinafter also referred to as organic EL elements). Inorganic electroluminescent elements have been used as planar light sources, but an alternating high voltage is required to drive the light emitting elements.

  On the other hand, an organic EL element has a structure in which a light emitting layer containing a compound that emits light is sandwiched between a cathode and an anode, and excitons (excitons) are generated by injecting electrons and holes into the light emitting layer and recombining them. The device emits light by utilizing the emission of light (fluorescence, phosphorescence) when the exciton is deactivated, and can emit light at a voltage of several volts to several tens of volts. Furthermore, since the organic EL element is a self-luminous type, the viewing angle is wide, the visibility is high, and the thin film type solid-state element has attracted attention from the viewpoints of space saving and portability. For future practical use, it is desired to develop an organic EL device that emits light with high power, high efficiency and low power consumption.

  As such an organic electroluminescence element, a fluorescent emission type using light emission from an excited singlet, a phosphorescent type using light emission from an excitation triplet, and the like are known as a light emitter.

  In the case of using light emission from an excited singlet, the generation ratio of singlet excitons and triplet excitons is 1: 3. Therefore, the generation probability of luminescent excited species is 25%, and the light extraction efficiency is about Since it is 20%, the limit of the external extraction quantum efficiency (ηext) is set to 5%.

  On the other hand, the organic EL device using phosphorescence emission from the excited triplet has an upper limit of 100% on the internal quantum efficiency, so that in principle the emission efficiency is four times that of the excited singlet, Since there is a possibility that a performance almost equal to that of a cathode tube may be obtained, it is also attracting attention as a lighting application. Such phosphorescent emitters have been studied mainly with transition metal complexes such as iridium complexes or platinum, and typical examples include orthometalated iridium complexes.

  These complexes are referred to as phosphorescent dopants because they are used by being dispersed and added in the light emitting layer together with a light emitting host material (or simply referred to as a host).

Since the performance (emission efficiency, emission lifetime, emission color, etc.) of the organic EL element varies greatly depending not only on the dopant but also on the host, the development of both has been conducted vigorously.
For example, in order to obtain high luminous efficiency, in the 10th International Works on Inorganic and Organic Electroluminescence (EL'00, Hamamatsu), Ikai et al. Uses a hole transporting compound as a host of a phosphorescent compound. In addition, M.M. E. In Thompson et al., Various electron transport materials are used as phosphorescent compound hosts, and they are doped with a novel iridium complex.

In any method, by appropriately selecting the dopant and the host, the light emission brightness and light emission efficiency of the light emitting device are greatly improved compared to conventional devices because the emitted light is derived from phosphorescence. However, the light emission lifetime of the element has a problem that it is shorter than that of a conventional fluorescent element.
In particular, in the case of a blue light-emitting element, the emission lifetime is extremely shortened, and a blue dopant that satisfies all the emission efficiency, emission wavelength, and emission lifetime has not yet been found, and its creation is urgent.

  Along with the development of blue dopants, the development of blue hosts that have a significant impact on the performance of organic EL devices has been actively conducted. In particular, a host composed of a combination of a carbazole derivative and a dibenzofuran derivative has been studied as a main material ( For example, see Patent Document 1). In addition, application of phosphine oxide derivatives using phosphorus atoms as heteroatoms to organic EL devices has also been attempted. Since these phosphine oxide derivatives have a wide band gap, adaptation to a blue dopant has been studied, but their performance is not yet sufficient, and intensive studies have been continued (for example, see Patent Documents 2 and 3).

International Publication No. 2011/004639 International Publication No. 2010/137779 JP 2004-253298 A

  Thus, depending on the above-described conventional compounds, the improvement of the light emission efficiency and the light emission lifetime of the organic EL element is insufficient, and further leap is demanded.

  Accordingly, an object of the present invention is to provide a material for an organic electroluminescence element having high luminous efficiency and a long lifetime, an organic electroluminescence element using the same, a display device, and a lighting device.

In order to achieve the above object of the present invention, according to one aspect of the present invention,
An organic electroluminescent element material represented by the following general formula (1) is provided.

  In general formula (1), X represents an oxygen atom, a sulfur atom, PR, PR (= Y) or SiRR, R represents an aromatic hydrocarbon group or an aromatic heterocyclic group, and Y represents an oxygen atom or a sulfur atom. Or represents a selenium atom. R1 to R8 are each independently a hydrogen atom or a substituent, and at least one is represented by the following general formula (2).

  In general formula (2), L represents an arylene group, a heteroarylene group, or a group in which an arylene group and a heteroarylene group are bonded, and Ar1 and Ar2 each represent an aryl group or a heteroaryl group which may have a substituent. Or a group in which an aryl group and a heteroaryl group are bonded to each other. Y represents an oxygen atom, a sulfur atom or a selenium atom.

According to another aspect of the invention,
A pair of electrodes;
An organic layer provided between the pair of electrodes and including a light-emitting layer,
The organic electroluminescent element is characterized in that the organic electroluminescent element material is contained in at least one of the organic layers.

According to still another aspect of the present invention,
A display device comprising the organic electroluminescence element is provided.

According to still another aspect of the present invention,
Provided is a lighting device comprising the organic electroluminescence element.

  According to the present invention, it is possible to provide a material for an organic electroluminescence element having high luminous efficiency and a long lifetime, and an organic electroluminescence element, a display device, and an illumination device using the material.

It is the schematic perspective view which showed an example of the structure of the display apparatus of this invention. It is the schematic perspective view which showed an example of the structure of the display part shown in FIG. It is a schematic perspective view which shows an example of the illuminating device using the organic EL element of this invention. It is a schematic perspective view which shows an example of the illuminating device using the organic EL element of this invention.

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

(I) Anode / light emitting layer / electron transport layer / cathode (ii) Anode / hole transport layer / light emitting layer / electron transport layer / cathode (iii) Anode / hole transport layer / light emitting layer / hole blocking layer / electron Transport layer / cathode (iv) Anode / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode (v) Anode / anode buffer layer / hole transport layer / light emitting layer / hole Blocking layer / electron transport layer / cathode buffer layer / cathode (vi) anode // hole transport layer / anode buffer layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode (vii) anode / anode Buffer layer / hole transport layer / light emitting layer / electron transport layer / cathode buffer layer / cathode

The light emitting layer may form a unit to form a light emitting layer unit. Further, a non-light emitting intermediate layer may be provided between the light emitting layers, and the intermediate layer may include a charge generation layer.
The organic EL element of the present invention preferably emits white light and is preferably a lighting device using these.

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

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

  An electron transport material (including a hole blocking material and an electron injection material) used for the electron transport layer only needs to have a function of transmitting electrons injected from the cathode to the light emitting layer. Can be selected from any conventionally known compounds. Moreover, as an electron transport material, the compound represented by General formula (1) mentioned later can also be used.

Examples of conventionally known materials used for the electron transport layer (hereinafter referred to as electron transport materials) include heterocyclic tetracarboxylic acid anhydrides such as nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, naphthalene perylene, And azacarbazole derivatives including carbodiimide, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives, carboline derivatives, and the like. Here, the azacarbazole derivative refers to one in which one or more carbon atoms constituting the carbazole ring are replaced with nitrogen atoms.
In the oxadiazole derivative, a thiadiazole derivative in which an oxygen atom of the oxadiazole ring is substituted with a sulfur atom, or a quinoxaline derivative having a quinoxaline ring known as an electron-withdrawing group can also be used as an electron transport material.
Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

  In addition, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq), 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 the central metals of these metal complexes are In, Mg, Metal complexes replaced with Cu, Ca, Sn, Ga or Pb can also be used as the electron transport material.

In addition, metal-free or metal phthalocyanine, or those having the terminal substituted with an alkyl group or a sulfonic acid group can also be used as the electron transport material.
Further, similarly to the hole injection layer and the hole transport layer, inorganic semiconductors such as n-type-Si and n-type-SiC can also be used as the electron transport material.

  The electron transport layer is made of an electron transport material such as a vacuum deposition method, a wet method (also referred to as a wet process, such as a spin coating method, a casting method, a die coating method, a blade coating method, a roll coating method, an ink jet method, a printing method, or a spraying method. The film can be formed by a known thinning method such as a coating method, a curtain coating method, or an LB method (Langmuir Brodgett method).

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

  Further, an electron transport layer having a high n property doped with impurities can also be used. 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.

  Hereinafter, although the specific example of the conventionally well-known compound (electron transport material) preferably used for formation of the electron carrying layer of the organic EL element of this invention is given, this invention is not limited to these.

  In addition, a compound represented by the following general formula (R-1) is more preferably used for forming the electron transport layer of the organic EL device of the present invention.

In the general formula (R-1), G _{1 to} G ₈ represent a nitrogen atom or —C (Rs) ═, and at least one of the G _{1 to} G ₈ represents a nitrogen atom. Rr is a substituent, and is preferably an alkyl group, a cycloalkyl group, an aromatic hydrocarbon group or an aromatic heterocyclic group. Rs represents a hydrogen atom or a substituent, and the substituent represented by Rs is preferably an alkyl group, a cycloalkyl group, an aromatic hydrocarbon group or an aromatic heterocyclic group, and an aromatic hydrocarbon group or It is more preferably an aromatic heterocyclic group.

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

  The total film thickness of the light emitting layer is not particularly limited, but from the viewpoint of improving the uniformity of the film, preventing unnecessary application of high voltage during light emission, and improving the stability of the emission color with respect to the drive current. It is preferably adjusted to a range of 2 nm to 5 μm, more preferably adjusted to a range of 2 nm to 200 nm, and particularly preferably adjusted to a range of 5 nm to 100 nm.

  For the formation of the light-emitting layer, a light-emitting dopant or a host compound, which will be described later, is used, for example, a vacuum deposition method, a wet coating method (also called a wet process, such as a spin coating method, a casting method, a die coating method, a blade coating method, a roll coating method) , An inkjet method, a printing method, a spray coating method, a curtain coating method, an LB method (Langmuir Brodgett method) and the like.

  The light emitting layer of the organic EL device of the present invention contains a light emitting dopant (phosphorescent dopant (also referred to as phosphorescent dopant, phosphorescent dopant group) or fluorescent dopant) compound and a light emitting host compound. Is preferred.

(1) Luminescent dopant compound A luminescent dopant compound (also referred to as a luminescent dopant) will be described.
As the light-emitting dopant, a fluorescent dopant (also referred to as a fluorescent compound) or a phosphorescent dopant (also referred to as a phosphorescent emitter, a phosphorescent compound, a phosphorescent compound, or the like) can be used.

(1.1) Phosphorescent dopant (also called phosphorescent dopant)
The phosphorescent dopant according to the present invention will be described.
The phosphorescent dopant compound according to the present invention is a compound in which light emission from an excited triplet is observed, specifically, 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 the phosphorescent dopant in principle.
One is that recombination of carriers occurs on the host compound to which carriers are transported to generate an excited state of the luminescent host compound, and this energy is transferred to the phosphorescent dopant to obtain light emission from the phosphorescent dopant. Energy transfer type.
The other is a carrier trap type in which a phosphorescent dopant serves as a carrier trap, carrier recombination occurs on the phosphorescent dopant, and light emission from the phosphorescent dopant compound is obtained.
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.

In the range which does not impair the objective effect of this invention, you may use together the compound etc. which are described in the following patent gazettes in the light emitting layer which concerns on the organic EL element of this invention.
For example, International Publication No. 00/70655, JP 2002-280178, JP 2001-181616, JP 2002-280179, JP 2001-181617, JP 2002-280180, JP 2001-247859 A, JP 2002-299060 A, JP 2001-313178 A, JP 2002-302671 A, JP 2001-345183 A, JP 2002-324679 A, International Publication. No. 02/15645, JP 2002-332291 A, JP 2002-50484 A, JP 2002-332292 A, JP 2002-83684 A, JP 2002-540572 A, JP 2002-2002 A. No. 117978, JP 2002-33858 JP, JP-A-2002-170684, JP-A-2002-352960, WO01 / 93642, JP-A-2002-50483, JP-A-2002-1000047, JP-A-2002-173684. JP-A-2002-359082, JP-A-2002-175484, JP-A-2002-363552, JP-A-2002-184582, JP-A-2003-7469, JP-A-2002-525808, JP 2003-7471, JP 2002-525833, JP 2003-31366, JP 2002-226495, JP 2002-234894, JP 2002-2335076, JP 2002 No. 2411751, JP 2001-319779 A. JP, 2001-319780, 2002-62824, 2002-100474, 2002-203679, 2002-343572, 2002-203678, etc. It is.

(1.2) Fluorescent dopants Fluorescent dopants (also referred to as fluorescent compounds) include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamines. And dyes having a high fluorescence quantum yield, such as laser dyes, and the like, dyes based on dyes, pyrylium dyes, perylene dyes, stilbene dyes, polythiophene dyes, and rare earth complex phosphors.

(1.3) Combined use with conventionally known light-emitting dopants The light-emitting dopants may be used in combination of a plurality of compounds, and combinations of phosphorescent dopants having different structures or phosphorescent dopants and fluorescent dopants. You may use it in combination.

  Here, specific examples of usable luminescent dopants are given as the luminescent dopant, but the present invention is not limited thereto.

(2) Host compound The host compound contained in the light emitting layer of the organic EL device of the present invention is preferably a compound having a phosphorescence quantum yield of phosphorescence emission at room temperature (25 ° C) of less than 0.1, More preferred is a compound having a phosphorescence quantum yield of less than 0.01.

  As the host compound, one type of compound may be used alone, or a plurality of types of compounds may be used in combination.

  The light-emitting host compound used in the present invention is not particularly limited in terms of structure, but typically, a carbazole derivative, a triarylamine derivative, an aromatic borane derivative, a nitrogen-containing heterocyclic compound, a thiophene derivative, a furan derivative, Those having a basic skeleton such as an oligoarylene compound, or a carboline derivative or a diazacarbazole derivative (here, a diazacarbazole derivative is a compound in which at least one carbon atom of a hydrocarbon ring constituting a carboline ring of a carboline derivative is nitrogen Represents an atom substituted with an atom.) And the like.

  The host compound used in the present invention may be a low molecular compound, a high molecular compound having a repeating unit, or a low molecular compound having a polymerizable group such as a vinyl group or an epoxy group (evaporation polymerizable light emitting host). Good.

  As the host compound, a compound having a hole transporting ability and an electron transporting ability, which prevents emission of longer wavelengths and has a high Tg (glass transition temperature) is preferable.

  In the present invention, the light emitting layer may have three layers. In that case, the host compound may be different for each light emitting layer, but when the same compound is used, excellent driving life characteristics and chromaticity are obtained. It is preferable because stability can be obtained.

  In addition, the host compound preferably has a lowest excited triplet energy (T1) larger than 2.7 eV because higher luminous efficiency can be obtained. The lowest excited triplet energy as used in the present invention refers to the peak energy of the emission band corresponding to the transition between the lowest vibrational bands of the phosphorescence emission spectrum observed at a liquid nitrogen temperature after dissolving the host compound in a solvent.

In the present invention, a compound having a glass transition point of 90 ° C. or higher is preferable, and a compound having a glass transition temperature of 130 ° C. or higher is preferable because excellent driving life characteristics can be obtained.
Here, the glass transition point (Tg) is a value obtained by a method based on JIS-K-7121 using DSC (Differential Scanning Colorimetry).

  In the organic EL device of the present invention, since the host material is responsible for carrier transport, a material having carrier transport capability is preferable. Carrier mobility is used as a physical property representing carrier transport ability, but the carrier mobility of an organic material generally depends on the electric field strength. Since a material having a high electric field strength dependency easily breaks the balance of hole and electron injection / transport, it is preferable to use a material having a low electric field strength dependency of mobility for the intermediate layer material and the host material.

  Here, for the purpose of the present invention described above, the present inventors considered the factors that hinder the improvement of the light emission characteristics and the light emission lifetime of the organic EL element, and in particular, the bond between carbon atom and phosphorus atom as the material for the organic EL element. Attention was paid to the use of a compound containing.

  The mechanism by which organic EL elements emit light consists of a series of processes such as charge transport, generation of excitons by recombination of electrons and holes, and light emission from excitons. It is necessary to have various properties such as transportability against charges (carrier transportability) and durability (carrier resistance) and durability against excitons. Since the material for an organic EL device repeats a transition to a radical state or an excited state in the device, it is expected that a subtle structural change occurs, and this is considered to break a carbon atom-phosphorus atom bond. Charges or excitons are considered to be related to frontier orbitals (HOMO and LUMO), and it is assumed that further improvement in performance can be achieved by separating the frontier orbitals in the molecule or by appropriately arranging the frontier orbitals. did.

  Based on the above considerations, the present inventors have developed a compound in which an electrically inactive (no HOMO or LUMO) linking group is introduced between a site where HOMO or LUMO is present and a phosphorus atom, and organic EL When used as a device material, the present inventors have found that the light emission life of the organic EL device is dramatically improved and at the same time the light emission efficiency is improved, and the present invention has been achieved.

Moreover, when the compound of this invention was used as an organic EL element material, it became clear that the voltage rise at the time of the drive of an organic EL element was suppressed. Although details are not yet clear, by using the compound of the present invention, the balance of charge (electrons and holes) was adjusted, the interface film quality with the adjacent layer was improved, or the compatibility with the dopant was improved. It is conceivable that the dispersibility of the dopant is improved. From the structural point of view, the compound of the present invention has a spherical partial structure and a flat partial structure, and these characteristics moderately regulate the interaction between organic molecules, improving the performance as described above. I guess that was seen.
Hereinafter, the organic EL element material of the present invention will be described in detail.

(2.1) Compound Represented by General Formula (1) The material for an organic EL device of the present invention is represented by the following general formula (1).

In the general formula (1), X represents an oxygen atom, a sulfur atom, PR, PR (= Y) or SiRR, preferably an oxygen atom or a sulfur atom, more preferably an oxygen atom.
R represents an aromatic hydrocarbon group (also referred to as an aryl group) or an aromatic heterocyclic group (also referred to as a heteroaryl group). Examples of the aromatic hydrocarbon group represented by R include a phenyl group, a xylyl group, a naphthyl group, an anthryl group, a fluorenyl group, a phenanthryl group, a biphenylyl group, a terphenyl group, and the like. Heterocyclic groups include pyridyl, pyrimidinyl, furyl, pyrrolyl, imidazolyl, benzimidazolyl, pyrazolyl, pyrazinyl, triazolyl, oxazolyl, benzoxazolyl, thiazolyl, isoxazolyl, isothiazolyl , Furazanyl group, thienyl group, quinolyl group, benzofuryl group, dibenzofuryl group, benzothienyl group, dibenzothienyl group, indolyl group, carbazolyl group, carbolinyl group, diazacarbazolyl group (which constitutes the carboline ring of the carbolinyl group) One of the carbon atoms is nitrogen Indicating those replaced by), quinoxalinyl group, a pyridazinyl group, a triazinyl group, a quinazolinyl group, a phthalazinyl group, and the like. As a carbon atom number of the aromatic hydrocarbon group or aromatic heterocyclic group represented by R, 2-20 are preferable and 6-12 are more preferable. The aromatic hydrocarbon group or aromatic heterocyclic group represented by R is preferably a phenyl group, biphenylyl group, terphenyl group, pyridyl group, pyrimidyl group, dibenzofuryl group, dibenzothienyl group, carbazolyl group, carbolinyl group. A phenyl group, a biphenylyl group, a terphenyl group, a dibenzofuryl group, a dibenzothienyl group, and a carbazolyl group, more preferably a phenyl group, a dibenzofuryl group, and a dibenzothienyl group. R may be further substituted with the same substituent as the substituent represented by R1 to R8 described later.
Y is an oxygen atom, a sulfur atom or a selenium atom, preferably an oxygen atom or a sulfur atom, and more preferably an oxygen atom.

In General formula (1), R1-R8 represents a hydrogen atom or a substituent.
In the general formula (1), examples of the substituent represented by R1 to R8 include an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon group (also referred to as an aryl group, such as a phenyl group and a xylyl group). , Naphthyl group, anthryl group, fluorenyl group, phenanthryl group, biphenylyl group, terphenyl group, etc.), non-aromatic heterocyclic group, aromatic heterocyclic group (also called heteroaryl group, for example, pyridyl group, pyrimidinyl group, Furyl group, pyrrolyl group, imidazolyl group, benzimidazolyl group, pyrazolyl group, pyrazinyl group, triazolyl group (for example, 1,2,4-triazol-1-yl group, 1,2,3-triazol-1-yl group, etc.) , Oxazolyl group, benzoxazolyl group, thiazolyl group, isoxazolyl group, isothiazolyl group, fraza Group, thienyl group, quinolyl group, benzofuryl group, dibenzofuryl group, benzothienyl group, dibenzothienyl group, indolyl group, carbazolyl group, carbolinyl group, diazacarbazolyl group (carbon constituting the carboline ring of the carbolinyl group) One of the atoms replaced by a nitrogen atom), quinoxalinyl group, pyridazinyl group, triazinyl group, quinazolinyl group, phthalazinyl group, etc.), halogen atom, alkoxyl group, cycloalkoxyl group, aryloxy group, alkylthio group, cycloalkylthio Group, arylthio group, alkoxycarbonyl group, aryloxycarbonyl group, sulfamoyl group, ureido group, acyl group, acyloxy group, amide group, carbamoyl group, sulfinyl group, alkylsulfonyl group, arylsulfonyl , An amino group, a nitro group, a cyano group, alkylphosphino group, an aryl phosphino group, alkylphosphoryl group, an aryl phosphoryl group, such as alkyl thiophosphoryl group or arylthio phosphoryl group. Preferably, an alkyl group, a cycloalkyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, a halogen atom, an alkoxyl group, a cycloalkoxyl group, an aryloxy group, an amino group, a nitro group, or a cyano group, more preferably , An aromatic hydrocarbon group, an aromatic heterocyclic group or an amino group, and more preferably an aromatic heterocyclic group or an amino group. Preferred aromatic hydrocarbon groups include a phenyl group, a naphthyl group, a fluorenyl group, and a biphenylyl group. Similarly, preferred aromatic heterocyclic groups include pyridyl group, pyrimidinyl group, benzoimidazolyl group, triazolyl group, thienyl group, quinolyl group, benzofuryl group, dibenzofuryl group, benzothienyl group, dibenzothienyl group, indolyl group, carbazolyl group. , A carbolinyl group, and a diazacarbazolyl group. Among them, a pyridyl group, a dibenzofuryl group, a dibenzothienyl group, a carbazolyl group, a carbolinyl group, and a diazacarbazolyl group are more preferable, and a dibenzofuryl group and a dibenzothienyl group are preferable. And a carbazolyl group is more preferable. Similarly, a preferred amino group is a diarylamino group, and a diphenylamino group is more preferred. These groups may be further substituted with the above-mentioned substituents, or they may be bonded to each other to form a ring.

  In the general formula (1), at least two of R1 to R8 are substituents, and at least one of the two substituents preferably has a structure represented by the following general formula (2). Further, the plurality of substituents represented by R1 to R8 are preferably not the same, and at least one substituent is preferably an aromatic hydrocarbon ring group or an aromatic heterocyclic group. Preferred examples of the aromatic hydrocarbon group or aromatic heterocyclic group include a phenyl group, a biphenyl group, a carbazolyl group, a carbolinyl group, a dibenzofuryl group, and a dibenzothienyl group, and are a phenyl group, a carbazolyl group, and a dibenzofuryl group. Is more preferable. These substituents may further have other substituents, and as such other substituents, a phenyl group, a pyridyl group, and a pyrimidyl group are preferable.

There is no particular limitation as to which of R1 to R8 in general formula (1) is represented by general formula (2), but any of R1, R3 to R6, and R8 is represented by general formula (2). It is preferable that any one of R3 to R6 is represented by the general formula (2), and it is most preferable that R4 or R5 is represented by the general formula (2).
R1 to R8 in the general formula (1) may each be a hydrogen atom, the above-described substituent, or the structure represented by the general formula (2), but R2 and R7 are hydrogen atoms. Is preferred. Furthermore, when any one of R1 to R4 is represented by the general formula (2), it is preferable that any one of R5 to R8 is a substituent and the other three are hydrogen atoms.

In General Formula (2), L is a linking group and represents an arylene group, a heteroarylene group, or a group in which an arylene group and a heteroarylene group are bonded. Here, the arylene group and the heteroarylene group represent a divalent linking group obtained by removing one hydrogen atom from the aryl group and the heteroaryl group, respectively.
In the general formula (2), the arylene group and heteroarylene group represented by L preferably have 6 to 15 carbon atoms, more preferably 6 to 12 carbon atoms, More preferably, the number is 6-10. Specifically, the arylene group represented by L is preferably a phenylene group, a naphthylene group, a biphenylene group or a fluorenylene group, more preferably a phenylene group or a biphenylene group, and a phenylene group. Further preferred. The heteroarylene group represented by L is preferably a pyridylene group, a thienylene group, a quinolylene group, a dibenzofurylene group, a dibenzothienylene group, a carbazolylene group, a carbolinylene group, or a diazacarbazolylene group, A pyridylene group, a dibenzofurylene group, a dibenzothienylene group, a carbazolylene group or a carbolinylene group is more preferred, and a pyridylene group is still more preferred. These linking groups may be further substituted with the above substituents.

  In General formula (2), Y represents an oxygen atom, a sulfur atom, or a selenium atom, preferably an oxygen atom or a sulfur atom, and more preferably an oxygen atom.

In the general formula (2), Ar1 and Ar2 each represents an aryl group, a heteroaryl group, or a group in which an aryl group and a heteroaryl group are bonded to each other. It may have a substituent. Examples of the substituent include the same ones as described above, and are preferably an aromatic hydrocarbon group, an aromatic heterocyclic group, an alkyl group or an arylphosphino group, and a dibenzofuryl group, a phenyl group or a pyridyl group. It is more preferably a group, and further preferably a phenyl group or a pyridyl group. These substituents may further have other substituents.
In the general formula (2), at least one of Ar1 and Ar2 is preferably represented by any of the following general formulas (4) to (6), and is represented by the general formula (4) or (5). More preferably.

  In the general formulas (4) to (6), Z represents a carbon atom or a nitrogen atom, and may be the same or different from each other. Note that when Z is a carbon atom, a hydrogen atom is bonded to the carbon atom.

  In the general formulas (5) and (6), the connection mode of each six-membered ring is not particularly limited, but is preferably connected at the m-position or p-position, and preferably connected at the m-position. More preferred.

  In General Formula (2), Ar1 and Ar2 are preferably represented by General Formula (4) or (5), and more preferably represented by General Formula (4).

(2.2) Compound represented by general formula (3) Preferable examples of the compound represented by general formula (1) include a compound represented by the following general formula (3).

  In General formula (3), X1 represents an oxygen atom or a sulfur atom, and is preferably an oxygen atom.

In the general formula (3), R1, R3, R4, Y, Ar1 and Ar2 have the same meanings as R1, R3, R4, Y, Ar1 and Ar2 in the general formula (1) and the general formula (2), and R1 , R3 and R4 each represents a substituent.
In particular, the substituent represented by R1, R3, or R4 is preferably an aromatic hydrocarbon group or an aromatic heterocyclic group, and is a carbazolyl group, carbolinyl group, diazacarbolinyl, or dibenzofuryl group. It is more preferable that it is a carbazolyl group. The substituents represented by R1, R3, and R4 may further have other substituents, and such other substituents are preferably aromatic hydrocarbon groups or aromatic heterocyclic groups. , A phenyl group, a phenylpyridyl group or a pyridyl group is more preferable.

The organic EL device material of the present invention may be used in any layer in the organic layer of the organic EL device, but should be used in at least one of the light emitting layer, the electron transport layer, and the hole transport layer. It is more preferable that it is used for at least one of the light emitting layer and the electron transporting layer, and it is more preferable that it is used for the light emitting layer. The organic EL device material of the present invention is most preferably used together with a phosphorescent dopant as a host material in the light emitting layer.
Moreover, when it has a pyridyl group or a pyrimidyl group in some organic EL element materials of this invention, it is preferable to use for an electron carrying layer.

(2.3) Specific Examples Hereinafter, examples of the organic EL element material according to the present invention will be described, but the present invention is not limited thereto.

(2.4) Synthesis Example of Compound Represented by General Formula (1) A synthesis example of the organic EL element material of the present invention will be described, but the method for producing the organic EL element material of the present invention is limited thereto. It is not something. Hereinafter, the synthesis method of the compounds (7) and (40) among the above specific examples will be described as an example.

(2.4.1) Synthesis of compound (7) of the present invention

Under a nitrogen stream, 150 ml of dehydrated tetrahydrofuran (THF) and 1.4 g of separately synthesized 3-bromo-9- (dibenzofuryl) carbazole were added to a 300 ml four-head flask and cooled in a dry ice / acetone bath. To this solution, 2.3 ml of n-butyllithium (n-BuLi, 1.64 Min Hexane) was added and stirred as it was for 1 hour. Further, 0.2 ml (0.26 g) of phenyldichlorophosphine was added to this reaction solution, and the mixture was stirred as it was for 1 hour, then returned to room temperature and stirred overnight. 100 ml of water was added to the reaction solution, and 50 ml of hydrogen peroxide (H ₂ O ₂ , 35 wt%) was further added, followed by stirring for 1 hour. The organic layer was separated, washed with water and saturated brine, and dried over magnesium sulfate. The solid was filtered off, the filtrate was concentrated under reduced pressure, and purified by column chromatography to obtain 0.87 g of the desired compound (7) of the present invention (yield 76%). The structure of the obtained compound was confirmed by NMR and Mass measurement.
In the preparation of the organic EL device described later, a sample obtained by further GPC purification and then sublimation purification of the compound (7) of the present invention was used.

(2.4.2) Synthesis of compound (40) of the present invention (1) Synthesis of intermediate (3- (diphenylphosphoryl) phenyl) boronic acid

Under a nitrogen stream, 100 ml of dehydrated tetrahydrofuran (THF) and 9.4 g of m-dibromobenzene were added to a 300 ml four-headed flask and cooled in a dry ice / acetone bath. To this solution, 27 ml of n-butyllithium (n-BuLi, 1.64 Min Hexane) was added dropwise while maintaining an internal temperature of −65 ° C. or lower. After stirring the reaction solution at −65 ° C. or lower for 1 hour, a solution prepared by mixing 8.0 g of chlorodiphenylphosphine with 50 ml of dehydrated THF was added dropwise while maintaining the internal temperature at −60 ° C. or lower. After completion of dropping, the mixture was stirred for 2 hours as it was, gradually returned to room temperature, and stirred overnight. To this reaction solution, 30 ml of water and 70 ml of hydrogen peroxide (H ₂ O ₂ , 35 wt%) were added in this order, and the mixture was stirred for 3 hours. The organic layer was separated, washed with water until neutral, further washed with saturated brine, and dried over magnesium sulfate. The solid was filtered off, the filtrate was concentrated under reduced pressure, and purified by column chromatography to obtain 8.7 g of the desired 3-bromophenyldiphenylphosphine oxide (yield 67%).

  Subsequently, under a nitrogen stream, 7.2 g of 3-bromophenyldiphenylphosphine oxide and 100 ml of dehydrated tetrahydrofuran (THF) were added to a 300 ml four-headed flask and cooled in a dry ice / acetone bath. To this solution, 15 ml of n-BuLi (1.64 Min Hexane) was added dropwise while maintaining the internal temperature at −70 ° C. or lower, and the mixture was further stirred for 1 hour. Further, 3.1 g of trimethoxyborane was added dropwise to this solution. After stirring for 2 hours, the temperature was gradually returned to room temperature and stirred overnight. To this solution, 50 ml of water and 30 ml of 1N hydrochloric acid were sequentially added and stirred for 1 hour, and then the organic layer was separated and washed twice with water and brine. Furthermore, after adding magnesium sulfate and drying, this was separated by filtration and the filtrate was concentrate | evaporated under reduced pressure. A small amount of ethyl acetate was added to the crude product, and further heptane was added. As a result, a solid was precipitated and was collected by filtration to obtain 2.9 g of the desired (3- (diphenylphosphoryl) phenyl) boronic acid ( Yield 45%). The structure of the obtained compound was confirmed by NMR.

(2) Synthesis of compound (40)

After adding 50 ml of dimethyl sulfoxide to a 100 ml three-headed flask and degassing by nitrogen bubbling, 1.2 g of 3- (8-bromodibenzofuranyl) -9-phenylcarbazole synthesized separately ((3- (diphenylphosphoryl)) ) Phenyl) boronic acid (1.0 g) was added, and potassium carbonate (0.7 g) and [1,1′-bis (diphenylphosphino) ferrocene] dichloropalladium (II) (150 mg) were added, and the internal temperature was 120 ° C. for 5 hours. Heated. After completion of the reaction, the mixture was allowed to cool, 300 ml of water and 250 ml of toluene were added, and the organic layer was washed with liquid separation, water and brine, and then dried over magnesium sulfate. The solid was filtered off, the filtrate was concentrated under reduced pressure, and the composition was purified by column chromatography to obtain 0.85 g of the desired compound (40) of the present invention (yield 50%). The structure of the obtained compound was confirmed by NMR and Mass measurement.
In the preparation of the organic EL device described later, a sample obtained by further purifying the compound (40) of the present invention after GPC purification and then sublimation was used.

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

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

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

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

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

Inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material. JP-A-11-251067, J. Org. Huang et. al. A so-called p-type hole transport material as described in a book (Applied Physics Letters 80 (2002), p. 139) can also be used.
In the present invention, it is preferable to use these materials because a light-emitting element with higher efficiency can be obtained.

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

Further, a hole transport layer having a high p property doped with impurities can be used. For example, JP-A-4-297076, JP-A-2000-196140, 2001-102175, J. Pat. Appl. Phys. 95, 5773 (2004), and the like.
In the present invention, it is preferable to use a hole transport layer having such a high p property because a device with lower power consumption can be produced.

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

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

  The hole blocking layer has a function of an electron transport layer in a broad sense, and is made of a hole blocking material having a function of transporting electrons and a very 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 said electron carrying layer can be used as a hole-blocking layer as needed.

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

  The hole blocking layer preferably contains a carbazole derivative or an azacarbazole derivative (wherein the azacarbazole derivative indicates that one or more carbon atoms constituting the carbazole ring are replaced with a nitrogen atom). .

  In the present invention, when a plurality of light emitting layers having different light emission colors are provided, the light emitting layer having the shortest wavelength of light emission is preferably closest to the anode among all the light emitting layers. In this case, it is preferable to additionally provide a hole blocking layer between the shortest wave layer and the light emitting layer next to the anode next to the shortest wave layer.

  Furthermore, it is preferable that 50% by mass or more of the compound contained in the hole blocking layer provided at the position has an ionization potential of 0.3 eV or more larger than the host compound of the shortest wave emitting layer.

The ionization potential is defined by the energy required to emit electrons at the HOMO (highest occupied orbital) level of the compound to the vacuum level, and can be determined by, for example, the following method.
(1) Using Gaussian 98 (Gaussian 98, Revision A.11.4, MJ Frisch, et al, Gaussian, Inc., Pittsburgh PA, 2002.), a molecular orbital calculation software manufactured by Gaussian, USA As a value (eV unit converted value) calculated by performing structure optimization using B3LYP / 6-31G *. This calculation value is effective because the correlation between the calculation value obtained by this method and the experimental value is high.
(2) The ionization potential can also be obtained by a method of directly measuring by photoelectron spectroscopy. For example, a method known as ultraviolet photoelectron spectroscopy can be suitably used by using a low energy electron spectrometer “Model AC-1” manufactured by Riken Keiki Co., Ltd.

  On the other hand, the electron blocking layer has a function of a hole transport layer in a broad sense and is made of a material that has a function of transporting holes and has an extremely small ability to transport electrons, and transports holes. By blocking electrons, the recombination probability of electrons and holes can be improved.

  Moreover, the structure of the said positive hole transport layer can be used as an electron blocking layer as needed. In the present invention, the thickness of the hole blocking layer and the electron blocking layer is preferably 3 nm to 100 nm, and more preferably 3 nm to 30 nm.

<< Injection layer: hole injection layer (anode buffer layer), electron injection layer (cathode buffer layer) >>
The injection layer includes a hole injection layer and an electron injection layer.
The injection layer is provided as necessary between the anode and the light emitting layer or the hole transport layer, and between the cathode and the light emitting layer or the electron transport layer.

  The injection layer is a layer provided between the electrode and the organic layer in order to lower the driving voltage and improve the light emission luminance. “The organic EL element and its industrialization front line (November 30, 1998, NT. The details are described in Volume 2, Chapter 2, “Electrode Materials” (pages 123 to 166) of “S.

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

  The details of the electron injection layer are also described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like, and specifically, metals represented by strontium, aluminum and the like. Buffer layer, alkali metal compound buffer layer typified by lithium fluoride, sodium fluoride, potassium fluoride, etc., alkaline earth metal compound buffer layer typified by magnesium fluoride, oxide buffer layer typified by aluminum oxide Etc.

  The injection layer is preferably a very thin film, and depending on the material, the film thickness is preferably in the range of 0.1 nm to 5 μm.

  In addition, the materials used for the hole injection layer and the electron injection layer can be used in combination with other materials. For example, the materials can be mixed and used in the hole transport layer or the electron transport layer. is there.

"anode"
As the anode in the organic EL element, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (4 eV or more) is preferably used.
Specific examples of such electrode 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) that can form a transparent conductive film may be used.

  The anode may be formed by depositing these electrode materials by a method such as vapor deposition or sputtering, and a desired shape pattern may be formed by a photolithography method, or when pattern accuracy is not so high (about 100 μm or more), A pattern may be formed through a mask having a desired shape at the time of vapor deposition or sputtering of the electrode material. In the case of using a coatable material such as an organic conductive compound, a wet film forming method such as a printing method or a coating method can be used.

  When light emission is extracted from the anode, it is desirable that the transmittance be greater than 10%, and the sheet resistance of the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 nm to 1 μm, preferably 10 nm to 200 nm.

"cathode"
On the other hand, a metal having a small work function (4 eV or less) (electron-injecting metal), an alloy, an electrically conductive compound, and a mixture thereof can be used as an electrode material for the cathode.
Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like.
Among these, from the point of durability against electron injection and oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than this, for example, a magnesium / silver mixture, Magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred.

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

In order to transmit the emitted light, it is advantageous that either the anode or the cathode of the organic EL element is transparent or translucent, so that the emission luminance is improved.
Moreover, after producing the said metal by the film thickness of 1 nm-20 nm to a cathode, the transparent or semi-transparent cathode can be produced by producing the electroconductive transparent material quoted by description of the anode on it, By applying this, an element in which both the anode and the cathode are transmissive can be manufactured.

《Support substrate》
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 type, such as glass, plastic, etc., and is transparent. May be opaque. When extracting light from the support substrate side, the support substrate is preferably transparent.
Examples of the transparent support substrate preferably used include glass, quartz, and a transparent resin film. A particularly preferable support substrate is a resin film capable of giving flexibility to the organic EL element.

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

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

  As a material for forming the barrier film, any material may be used as long as it has a function of suppressing 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. Furthermore, in order to improve the brittleness of the barrier film, it is more preferable to have a laminated structure of these inorganic layers and layers made of organic materials. 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, the sputtering method, the reactive sputtering method, the molecular beam epitaxy method, the cluster ion beam method, the ion plating method, the plasma treatment method, the atmospheric pressure plasma treatment. Method, plasma CVD method, laser CVD method, thermal CVD method, coating method and the like can be used, but those by atmospheric pressure plasma treatment method as described in JP-A-2004-68143 are 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, 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.

Moreover, a hue improving 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 may be used in combination. In the case of using a color conversion filter, the λ _max of light emission of the organic EL element is preferably 480 nm or less.

<< Method for Manufacturing Organic EL Element >>
As an example of a method for producing an organic EL device, a method for producing an organic EL device comprising an anode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer / cathode explain.

  First, a thin film made of a desired electrode material, for example, an anode material, is formed on a suitable substrate so as to have a thickness of 1.0 μm or less, preferably 10 nm to 200 nm, to produce an anode.

  Next, a thin film containing an organic compound such as a hole injection layer, a hole transport layer, a light emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer is sequentially formed on the anode.

  In the organic EL device of the present invention, the light emitting layer when the compound represented by the general formula (1) according to the present invention is used for the light emitting layer, and the cathode and the electron transport layer adjacent to the cathode are applied by a wet method. -It is preferable to form a film.

  Examples of wet coating methods include spin coating, casting, die coating, blade coating, roll coating, ink jet, printing, spray coating, curtain coating, and LB, but a precise thin film is formed. From the viewpoint of possible 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. Different film forming methods may be applied for each layer.

  Examples of the liquid medium for dissolving or dispersing the organic EL device material according to the present invention include ketones such as methyl ethyl ketone and cyclohexanone, fatty acid esters such as ethyl acetate, halogenated hydrocarbons such as dichlorobenzene, toluene, xylene, Aromatic hydrocarbons such as mesitylene and cyclohexylbenzene, aliphatic hydrocarbons such as cyclohexane, decalin, and dodecane, and organic solvents such as dimethylformamide (DMF) and dimethylsulfoxide (DMSO) can be used. As a dispersion method, it is possible to disperse by a dispersion method such as ultrasonic wave, high shearing force dispersion or media dispersion.

  After sequentially forming these layers, a thin film made of a cathode material is formed thereon so as to have a thickness of 1 μm or less, preferably in the range of 50 nm to 200 nm, and a desired organic EL element is obtained by providing a cathode. can get.

  Alternatively, the cathode, electron injection layer, electron transport layer, hole blocking layer, light emitting layer, hole transport layer, hole injection layer, and anode can be formed in this order in the reverse order.

  When a DC voltage is applied to the multicolor display device thus obtained, light emission can be observed by applying a voltage of about 2 V to 40 V with the anode as + and the cathode as-polarity. An alternating voltage may be applied. The alternating current waveform to be applied may be arbitrary.

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

<Sealing>
In the organic EL device of the present invention, the anode, the cathode, and each layer provided between the anode and the cathode are preferably sealed from the outside air by a sealing member.

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

  The sealing member may be disposed so as to cover the display area of the organic EL element, and may be a concave plate shape or a flat plate shape. Further, transparency and electrical insulation are not particularly limited.

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

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

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

As the adhesive, specifically, photo-curing and thermosetting adhesives having reactive vinyl groups of acrylic acid oligomers, methacrylic acid oligomers, moisture-curing adhesives such as 2-cyanoacrylates, Examples thereof include epoxy-based heat and chemical curing type (two-component mixing), hot melt type polyamide, polyester, polyolefin, and cationic curing type ultraviolet curing epoxy resin adhesive.
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.

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

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

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

  Examples of hygroscopic compounds include metal oxides (sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide, etc.), sulfates (sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate, etc.), metals Halides (calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide, etc.), perchloric acids (barium perchlorate, magnesium perchlorate, etc.) Among them, 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 organic EL element, a protective film or a protective plate may be provided outside the sealing film or sealing film on the side facing the support substrate with the organic layer interposed therebetween. In particular, when sealing is performed with a sealing film, the mechanical strength is not necessarily high, and thus it is preferable to provide such a protective film or 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》
The organic EL element emits light inside a layer having a refractive index higher than that of air (refractive index is about 1.7 to 2.1) and can extract only about 15% to 20% of the light generated in the light emitting layer. It is generally said. This is because light incident on the interface (transparent substrate-air interface) at an angle θ greater than the critical angle causes total reflection and cannot be taken out of the organic EL element, or is transparent to the transparent electrode or light-emitting layer. This is because light undergoes total reflection with the substrate, and the light is guided through the transparent electrode or the light emitting layer, and as a result, the light escapes in the side direction of the organic EL element.

  As a method 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 interface between the transparent substrate and the air (US Pat. No. 4,774,435), substrate A method of improving efficiency by imparting light condensing properties (Japanese Patent Laid-Open No. Sho 63-314795), a method of forming a reflective surface on the side surface of an organic EL element (Japanese Patent Laid-Open No. 1-220394), a substrate, A method of forming an antireflection film by introducing a flat layer having an intermediate refractive index between the light emitters (Japanese Patent Laid-Open No. 62-172691), and having a lower refractive index than the substrate between the substrate and the light emitter. A method of introducing a flat layer (Japanese Patent Laid-Open No. 2001-202827), 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) (Japanese Patent Laid-Open No. 11-283951) Etc.)

  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 one 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 organic EL device having further high luminance or durability.

When a medium having a low refractive index is formed between the transparent electrode and the transparent substrate with a thickness longer than the wavelength of light, the light extracted from the transparent electrode has a higher extraction efficiency to the outside as the refractive index of the medium is lower.
Examples of the low refractive index layer include aerogel, porous silica, magnesium fluoride, and a fluorine-based polymer. Since the refractive index of the transparent substrate is generally about 1.5 to 1.7, the low refractive index layer preferably has a refractive index of about 1.5 or less, and more preferably 1.35 or less. .

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

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

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

As described above, the position where the diffraction grating is introduced may be in any of the layers or in the medium (in the transparent substrate or in the transparent electrode), but is preferably in the vicinity of the organic light emitting layer where light is generated.
At this time, the period of the diffraction grating is preferably about 1/2 to 3 times the wavelength of light in the medium.

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

<Condenser sheet>
The organic EL element of the present invention is processed in a microlens array-like structure on the light extraction side of the substrate, or combined with a condensing sheet, for example, in a specific direction, for example, an organic EL element light emitting surface. On the other hand, the brightness | luminance in a specific direction can be raised by condensing in a front 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 10 μm to 100 μm. If it becomes smaller than this, the effect of diffraction will generate | occur | produce and color, and if too large, thickness will become thick and is not preferable.

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

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

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

<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 Examples include, but are not limited to, the light source of the sensor. In particular, it can be effectively used 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. Can be used.

  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 (Konica Minolta Sensing Co., Ltd.) is applied to the CIE chromaticity coordinates.

When the organic EL element of the present invention is a white element, white means that the chromaticity in the CIE 1931 color system at 1000 cd / m ² is X = 0 when the 2 ° viewing angle front luminance is measured by the above method. .33 ± 0.07, Y = 0.33 ± 0.1.

<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. However, the vapor deposition method, the ink jet method, the spin coating method, and the printing method are preferable.

  The configuration of the organic EL element included in the display device is selected from the organic EL elements of the present invention as necessary. Moreover, the manufacturing method of an organic EL element is as having shown in the one aspect | mode of the manufacturing method of the organic EL element of the above-mentioned this 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. 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 display devices and displays, full-color display is possible by using three types of organic EL elements of red, green, and blue 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 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. The present invention is not limited to these examples.

  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. 1 is a schematic perspective view showing an example of the configuration of a display device composed of the organic EL element of the present invention, which displays image information by light emission of the organic EL element, for example, a display such as a mobile phone FIG.
As shown in FIG. 1, 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.
The control unit B sends a scanning signal and an image data signal to each of the plurality of pixels based on image information from the outside. As a result, each pixel sequentially emits light according to the image data signal for each scanning line by the scanning signal, and the image information is displayed on the display unit A.

FIG. 2 is a schematic diagram of the display unit A shown in FIG.
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.
FIG. 2 shows a case where the light emitted from the pixel 3 is extracted in the direction of the white arrow (downward).
Each of the scanning lines 5 and the plurality of data lines 6 in the wiring portion is made of a conductive material. The scanning lines 5 and the data lines 6 are orthogonal to each other in a grid pattern and are connected to the pixels 3 at the orthogonal positions (details are not shown).
When a scanning signal is transmitted 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 in the same substrate on the same substrate.

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

The organic EL element of the present invention may be used as an organic EL element having a resonator structure, and 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. Furthermore, 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. By using two or more kinds of the organic EL elements of the present invention having different emission colors, a full-color display device can be produced.

  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 red, green and blue, or two using the complementary colors such as blue and yellow, blue green and orange. 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, an electrode film or the like 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.

  There is no restriction | limiting in particular as a luminescent material used for a light emitting layer, For example, if it is a backlight in a liquid crystal display element, the metal complex which concerns on this invention so that it may suit the wavelength range corresponding to CF (color filter) characteristic, Any one of known luminescent materials may be selected and combined 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 glass substrate having a thickness of 300 μm is used as a sealing substrate, and an epoxy-based photocurable adhesive (LUX TRACK manufactured by Toagosei Co., Ltd.) is used as a sealing material. LC0629B) is applied, and this is overlaid on the cathode to be in close contact with the transparent support substrate, irradiated with UV light from the glass substrate side, cured and sealed, and as shown in FIG. 3 and FIG. Can be formed.

FIG. 3 shows a schematic diagram of the illumination device.
As shown in FIG. 3, the organic EL element 101 is covered with a glass cover 102. The sealing operation with the glass cover 102 is performed in a glove box (in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more) in a nitrogen atmosphere without bringing the organic EL element 101 into contact with the atmosphere.

FIG. 4 shows a cross-sectional view of the lighting device.
As shown in FIG. 4, the cathode 105 and the organic EL layer 106 are formed on a glass substrate 107 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 "%" is used in an Example, unless otherwise indicated, "mass%" is represented.
Moreover, the compound used by the following Example is represented by a following formula.

<< Production of Organic EL Element 1-1 >>
An ITO film having a film thickness of 100 nm was formed on a glass substrate of 100 mm × 100 mm × 1.1 mm, patterned, and this ITO transparent electrode substrate was ultrasonically cleaned with isopropyl alcohol and dried with dry nitrogen gas. UV ozone cleaning was performed for 5 minutes.

This transparent electrode substrate is fixed to a substrate holder of a vacuum evaporation apparatus, 200 mg of α-NPD is added as a hole transport material to a molybdenum resistance heating boat, and the compound of Comparative 1 is used as a host compound in another resistance heating boat made of molybdenum. put 200mg, the D-50 put 100mg as a light emitting dopant compound in a third resistive heating molybdenum boat, further Alq ₃ was placed 200mg of the electron transport material in a third resistive heating molybdenum boat, mounted in a vacuum deposition apparatus.

Next, after depressurizing the vacuum chamber to 4 × 10 ⁻⁴ Pa, α-NPD was deposited on the transparent support substrate at a deposition rate of 0.1 nm / second to provide a 40 nm-thick hole transport layer.

  Furthermore, Comparative 1 as the host compound and D-50 as the dopant compound were co-deposited on the hole transport layer at a deposition rate of 0.2 nm / second and 0.012 nm / second, respectively, to emit light having a thickness of 40 nm. A layer was provided.

Subsequently, Alq ₃ was deposited on the light emitting layer at a deposition rate of 0.1 nm / second to provide an electron transport layer having a thickness of 20 nm. The substrate temperature during vapor deposition was room temperature.

  Subsequently, lithium fluoride was vapor-deposited to provide a cathode buffer layer with a thickness of 0.5 nm, aluminum was vapor-deposited to provide a cathode with a thickness of 150 nm, and an organic EL element 1-1 was produced.

<< Production of Organic EL Elements 1-2 to 1-15 >>
In the production of the organic EL device 1-1, the host compound was changed to the compounds shown in Table 1.
Other than that produced the organic EL element 1-2 to 1-15 similarly.

<< Evaluation of Organic EL Elements 1-1 to 1-15 >>
After the production of the organic EL element, the non-light emitting surfaces of the organic EL elements 1-1 to 1-15 are covered with a glass case, a glass substrate having a thickness of 1.1 mm is used as a sealing substrate, and an epoxy-based material is used as a sealant around the periphery. A photo-curing adhesive (Lux Track LC0629B manufactured by Toagosei Co., Ltd.) is applied, and this is overlaid on the cathode and brought into close contact with the transparent support substrate. The glass substrate is irradiated with UV light, cured, and sealed. Then, an illuminating device having a configuration as shown in FIGS. 3 and 4 was constructed, and this was used as a sample.
The following evaluation was performed on each sample thus produced. The evaluation results are shown in Table 1.

(1) Luminous efficiency (measurement of external extraction quantum efficiency)
The organic EL element is allowed to emit light at room temperature (about 23 ° C. to 25 ° C.) under a constant current condition of ^2.5 mA / cm ² and light emission luminance (L) [cd / m ² ] immediately after the start of light emission is measured. Thus, the external extraction quantum efficiency (η) was calculated. CS-2000 (manufactured by Konica Minolta Sensing) was used for measuring the emission luminance.
The light emission efficiency (external extraction quantum efficiency) was expressed as a relative value with the light emission luminance of the organic EL element 1-3 being 100, and represented by two significant digits.

(2) Luminous life The organic EL device emits light continuously at room temperature (about 23 ° C. to 25 ° C.) under a constant current condition of ^2.5 mA / cm ² , and the light emission luminance is half the initial luminance. The time required to become (half-life τ1 / 2) was measured, and this was used as a measure of the emission lifetime.
The light emission lifetime was expressed as a relative value with the half-life of the organic EL element 1-3 being 100, and represented by two significant digits.

(3) Drive voltage The organic EL element is caused to emit light under a constant current condition of ^2.5 mA / cm ² , and the drive voltage (initial drive voltage) at that time and the drive voltage when the light emission luminance reaches 50% are measured. ΔV = (initial driving voltage−driving voltage at 50% luminance) was calculated.
ΔV is expressed as a relative value where ΔV of the organic EL element 1-3 is 100.

(4) Summary As shown in Table 1, the organic EL elements 1-4 to 1-15 of the present invention are superior in luminous efficiency and emission lifetime compared to the organic EL elements 1-1 to 1-3 of the comparative example. Is long. This is considered because the decomposition | disassembly of the molecule | numerator in a light emitting layer was suppressed. Furthermore, in the organic EL elements 1-4 to 1-15 of the present invention, the change in driving voltage is also suppressed, and this point is also attributed to improved molecular stability as well as the emission lifetime. Conceivable.
From the above, it is effective to use the organic EL element material of the present invention as a host compound for improving the light emission efficiency and lifetime of the organic EL element, and at the same time, an organic EL element with little change in driving voltage can be obtained. I understand that.

<< Preparation of Organic EL Element 2-1 >>
On a transparent electrode substrate prepared in the same manner as in Example 1, poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) was diluted to 70% with pure water. Using this solution, a thin film was formed by spin coating under conditions of 3000 rpm and 30 seconds, and then dried at 200 ° C. for 1 hour to provide a first hole transport layer having a thickness of 20 nm.

  A solution of 3 mg of hole transport material HT-1 (TPD) and 40 mg of hole transport material HT-2 (α-NPD) dissolved in 10 ml of toluene on the first hole transport layer in a nitrogen atmosphere. A thin film was formed by spin coating under conditions of 1500 rpm and 30 seconds, and further irradiated with ultraviolet light for 180 seconds to carry out photopolymerization and crosslinking, thereby providing a second hole transport layer having a thickness of about 20 nm.

  On this second hole transport layer, 100 mg of Comparative 2 as the host compound and 10 mg of D-50 as the light-emitting dopant compound were each dissolved in 10 ml of toluene under the conditions of 600 rpm and 30 seconds. A thin film was formed by spin coating. It vacuum-dried at 80 degreeC for 1 hour, and provided the light emitting layer with a film thickness of about 60 nm.

Further, a thin film was formed on this light emitting layer by spin coating under a condition of 1000 rpm for 30 seconds using a solution of 50 mg of ET-40 dissolved in 10 ml of butanol, followed by vacuum drying at 60 ° C. for 1 hour. An electron transport layer having a thickness of about 30 nm was provided.
The cathode buffer layer and the cathode were formed by the same method as in Example 1.

<< Production of Organic EL Elements 2-2 to 2-15 >>
In the production of the organic EL element 2-1, the host compound was changed to the compounds shown in Table 2.
Other than that produced the organic EL element 2-2 to 2-15 similarly.

<< Evaluation of Organic EL Elements 2-1 to 2-15 >>
When evaluating the produced organic EL elements 2-1 to 2-15, these organic EL elements were sealed in the same manner as the organic EL elements 1-1 to 1-15 of Example 1, and FIGS. A lighting device as shown in FIG.
Each sample thus produced was evaluated for light emission efficiency, light emission lifetime, and driving voltage in the same manner as in Example 1. The evaluation results are shown in Table 2. The light emission efficiency, light emission lifetime, and drive voltage in Table 2 were expressed as relative values with each characteristic value of the organic EL element 2-2 being 100.
The evaluation results are shown in Table 2.

As shown in Table 2, the organic EL elements 2-3 to 2-15 of the present invention in which each organic layer was formed by a wet coating method emitted light compared to the organic EL elements 2-1 and 2-2 of the comparative examples. Excellent efficiency and significantly longer emission life. This is presumably because the material forming the light emitting layer was stabilized. Similarly to Example 1, the organic EL elements 2-3 to 2-15 of the present invention have a small change in driving voltage, and this point is also considered to be due to the improved stability of the light emitting layer.
From the above, even when an organic layer of an organic EL element is produced by a coating method, the organic EL element material of the present invention is used as a host compound of the light emitting layer in order to improve the light emission efficiency, the light emission lifetime and the element stability. It turns out that it is effective to use. Therefore, like Example 1, even if each organic layer is formed by a coating method instead of the vapor deposition method, it can be said that the effect by using the organic EL element material of the present invention is remarkably exhibited.

<< Production of Organic EL Element 3-1 >>
In the production of the organic EL element 1-1, the host compound of the light emitting layer was changed to host compound A, the electron transport material of the electron transport layer was changed to Comparative 1, and Comparative 1 was deposited on the light emitting layer at a deposition rate of 0.2 nm / An electron transport layer having a thickness of 25 nm was provided by vapor deposition in seconds.
Other than that produced the organic EL element 3-1.
The host compound A used as the host compound is represented by the following formula.

<< Production of Organic EL Elements 3-2 to 3-9 >>
In preparation of the organic EL element 3-1, the electron transport material of the electron transport layer was changed to the compounds shown in Table 3.
Other than that produced the organic EL element 3-2-3-10 similarly.

<< Evaluation of Organic EL Elements 3-1 to 3-10 >>
When evaluating the produced organic EL elements 3-1 to 3-10, these organic EL elements were sealed in the same manner as the organic EL elements 1-1 to 1-15 of Example 1, and FIGS. A lighting device as shown in FIG.
Each sample thus produced was evaluated for light emission efficiency, light emission lifetime, and driving voltage in the same manner as in Example 1. The evaluation results are shown in Table 3. The light emission efficiency, light emission lifetime, and drive voltage in Table 3 were expressed as relative values with each characteristic value of the organic EL element 3-1 being 100.
Table 3 also shows the initial drive voltage of each organic EL element. The initial drive voltage was expressed as a relative value with the value of the initial drive voltage of the organic EL element 3-1 being 100.
The evaluation results are shown in Table 3.

  As shown in Table 3, the organic EL elements 3-3 to 3-10 using the organic EL element material of the present invention for the electron transport layer are compared with the organic EL elements 3-1 and 3-2 of the comparative example. Excellent luminous efficiency and long luminous lifetime. In addition, the organic EL elements 3-3 to 1-10 of the present invention not only lower the initial driving voltage, but also suppress the voltage increase during the initial driving, and the organic EL element material of the present invention. It can be seen that an organic EL element with low voltage and little change in driving voltage can be provided by using as an electron transporting material for the electron transporting layer. These effects are considered to be because the organic EL device material of the present invention used as an electron transporting material is not only excellent in electron transporting property but also excellent in stability.

<Production of full-color display device>
(1) Production of Blue Light-Emitting Element The organic EL element 1-13 of Example 1 was a blue light-emitting element.

(2) Preparation of green light emitting element In preparation of the organic EL element 1-14 of Example 1, D-50 as a dopant compound was changed into D-1.
Other than that produced the green light emitting element similarly.

(3) Preparation of red light emitting element In preparation of the organic EL element 1-14 of Example 1, D-50 as a dopant compound was changed into D-10.
Otherwise, a red light emitting device was produced in the same manner.

(4) Production of Display Device The red, green, and blue light emitting organic EL elements produced above were arranged in parallel on the same substrate, and an active matrix type full color display device having a form as shown in FIG. 1 was produced.

In FIG. 2, only the schematic diagram of the display part A of the produced display device is shown.
As shown in FIG. 2, the display unit A includes a wiring unit including a plurality of scanning lines 5 and data lines 6 on the same substrate, and a plurality of pixels 3 arranged in parallel (light emission color of red region pixels, green region pixels). Pixel, blue region pixel, etc.). Each of the scanning lines 5 and the plurality of data lines 6 in the wiring portion is made of a conductive material. The scanning lines 5 and the data lines 6 are orthogonal to each other in a grid pattern, 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 in which an organic EL element corresponding to each emission color, a switching transistor as an active element, and a driving transistor are provided, and a scanning signal is transmitted from the scanning line 5. The image data signal is received from the data line 6 and light is emitted according to the received image data. In this manner, a full color display device was manufactured by appropriately arranging the red, green, and blue pixels 3 in parallel.

  It was confirmed that when the obtained full-color display device was driven, high brightness, high durability, and clear full-color moving image display were obtained.

<< Preparation of white light emitting element and white lighting device >>
The electrode of the transparent electrode substrate described in Example 1 was patterned to 20 mm × 20 mm, and each layer was formed in the same manner as in Example 1 thereon.

  First, α-NPD was deposited on a transparent substrate to provide a 25 nm-thick hole transport layer.

  Next, a molybdenum resistance heating boat containing the compound (43) of the present invention as a host compound and a molybdenum resistance heating boat containing D-10 and D-26 as dopant compounds were energized independently, The deposition rate of the compound (43) of the present invention, which is a host compound, and D-26, D-10, which are luminescent dopants, was adjusted to be 100: 5: 0.6, and a luminescent layer having a thickness of 30 nm was provided. .

Next, a 10 nm-thick hole blocking layer was provided using BAlq. Further, an electron transporting layer having a thickness of 40nm using Alq _3.

Furthermore, a stainless steel square mask with the same shape as the transparent electrode is installed on the electron injection layer, lithium fluoride is deposited to provide a 0.5 nm thick cathode buffer layer, and aluminum is deposited. Thus, a cathode having a thickness of 150 nm was provided.
In this way, an organic EL element was produced.

  The produced organic EL element was sealed in the same manner as in Example 1 to produce an illumination device as shown in FIGS.

  When the manufactured lighting device was energized, almost white light was obtained, confirming that it could be used as a lighting device.

<< Preparation of white light emitting element and white lighting device >>
A transparent substrate provided with this ITO transparent electrode after patterning on a substrate (NA45 manufactured by NH Techno Glass Co., Ltd.) on which a 100 nm ITO (indium tin oxide) film was formed as an anode on a 100 mm × 100 mm × 1.1 mm glass substrate The supporting substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and UV ozone cleaning was performed for 5 minutes.

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

  The substrate was transferred to a nitrogen atmosphere, and a solution of 50 mg of commercially available ADS254BE (American Dye Source, Inc.) dissolved in 10 ml of toluene was used on the first hole transport layer under conditions of 2500 rpm and 30 seconds. A thin film was formed by spin coating. It vacuum-dried at 60 degreeC for 1 hour, and provided the 2nd positive hole transport layer.

  Next, 100 mg of the compound (44) of the present invention, 0.5 mg of D-10 and 18 mg of D-50 and 10 ml of butyl acetate were used as a host compound, and spin-coated under conditions of 1000 rpm and 30 seconds. A thin film was formed by the method. Furthermore, it vacuum-dried at 60 degreeC for 1 hour, and provided the light emitting layer.

  Further, a thin film was formed by spin coating at 2000 rpm for 30 seconds using a solution obtained by dissolving 30 mg of the compound (30) of the present invention in 5 ml of hexafluoroisopropanol (HFIP), and then vacuum-dried at 60 ° C. for 1 hour. Thus, a first electron transport layer was provided.

  Subsequently, this substrate was fixed to a substrate holder of a vacuum deposition apparatus, 200 mg of ET-7 was put in a molybdenum resistance heating boat, and attached to the vacuum deposition apparatus.

After depressurizing the vacuum tank to 4 × 10 ⁻⁴ Pa, the molybdenum resistance heating boat containing ET-7 was energized and heated, and deposited on the first electron transport layer at a deposition rate of 0.1 nm / second. Thus, a second electron transport layer having a thickness of 20 nm was provided.
The substrate temperature during vapor deposition was room temperature.

  Subsequently, lithium fluoride was vapor-deposited to provide a cathode buffer layer having a thickness of 0.5 nm, and aluminum was vapor-deposited to provide a cathode having a thickness of 110 nm to produce an organic EL device.

  The produced organic EL element was sealed in the same manner as in Example 1 to produce an illumination device as shown in FIGS.

  When the manufactured lighting device was energized, almost white light was obtained, confirming that it could be used as a lighting device.

DESCRIPTION OF SYMBOLS 1 Display 3 Pixel 5 Scan line 6 Data line 101 Organic EL element 102 Glass cover 105 Cathode 106 Organic EL layer 107 Transparent electrode exhausted glass substrate 108 Nitrogen gas 109 Water trapping agent A Display part B Control part

Claims (9)

An organic electroluminescent element material represented by the following general formula (1).

[In general formula (1), X represents an oxygen atom, a sulfur atom, PR, PR (= Y) or SiRR, R represents an aromatic hydrocarbon group or an aromatic heterocyclic group, Y represents an oxygen atom, sulfur Represents an atom or selenium atom. R1 to R8 are each independently a hydrogen atom or a substituent, and at least one is represented by the following general formula (2). ]

[In General Formula (2), L represents an arylene group, a heteroarylene group, or a group in which an arylene group and a heteroarylene group are bonded, and Ar1 and Ar2 each represent an aryl group or heteroaryl which may have a substituent. Or a group in which an aryl group and a heteroaryl group are bonded to each other. Y represents an oxygen atom, a sulfur atom or a selenium atom. ]   In the said General formula (1), X is an oxygen atom or a sulfur atom, The organic electroluminescent element material of Claim 1 characterized by the above-mentioned.   In the general formula (1), at least one of the substituents represented by R1 to R8 is any one of a carbazolyl group, a carbolinyl group, a dibenzofuryl group, and a dibenzothienyl group. 2. The material for an organic electroluminescence element according to 2.   In the said General formula (2), L is an arylene group, The organic electroluminescent element material as described in any one of Claims 1-3 characterized by the above-mentioned. A pair of electrodes;
An organic layer having a multi-layer structure including a light emitting layer provided between the pair of electrodes,
The organic electroluminescent element as described in any one of Claims 1-4 is contained in at least one layer among the said organic layers, The organic electroluminescent element characterized by the above-mentioned.   The organic electroluminescent element according to claim 5, wherein the organic layer containing the material for an organic electroluminescent element is a light emitting layer or an electron transporting layer.   The organic electroluminescence device according to claim 5 or 6, wherein at least one of the organic layers is formed by a wet process.   A display device comprising the organic electroluminescence element according to claim 5.   The illuminating device provided with the organic electroluminescent element of any one of Claims 5-7.

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