JP2006282966A - Organic electroluminescent device material, organic electroluminescent device, display device and lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminescent device material having high luminous efficiency and a long emission life and an organic electroluminescent device. <P>SOLUTION: The organic electroluminescent device material is a metal complex of Ir, Rh, Os and the like represented by formula (1), and the tridentate ligand P<SB>1</SB>or P<SB>2</SB>has a ≥2C substituent which inhibits bidentate. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an organic electroluminescence element material, and an organic electroluminescence element, a display device, and an illumination device using the same.

  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. The 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, injects electrons and holes into the light emitting layer, and recombines them to generate excitons (exciton). It is an element that emits light by using light emission (fluorescence / phosphorescence) when this exciton is deactivated, and can emit light at a voltage of several volts to several tens of volts, and is also self-luminous. In addition, it is attracting attention from the viewpoints of space saving, portability and the like because it is a thin film type complete solid element with a wide viewing angle and high visibility.

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

  In Japanese Patent No. 3093796, a small amount of a phosphor is doped into a stilbene derivative, a distyrylarylene derivative or a tristyrylarylene derivative to achieve an improvement in light emission luminance and a longer device lifetime.

  Further, an element having an organic light-emitting layer in which an 8-hydroxyquinoline aluminum complex is used as a host compound and a small amount of phosphor is doped thereto (for example, JP-A 63-264692), and an 8-hydroxyquinoline aluminum complex is used as a host compound. For example, an element having an organic light emitting layer doped with a quinacridone dye (for example, JP-A-3-255190) is known.

  As described above, when light emission from an excited singlet is used, the generation ratio of singlet excitons and triplet excitons is 1: 3, so the generation probability of luminescent excited species is 25%, and the light extraction efficiency is high. Is about 20%, so the limit of the external extraction quantum efficiency (ηext) is 5%.

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

  When excited triplets are used, the upper limit of internal quantum efficiency is 100%, so that in principle the luminous efficiency is four times that of excited singlets, and there is a possibility that almost the same performance as cold cathode tubes can be obtained. Therefore, it is attracting attention as a lighting application.

  For example, S.M. Lamansky et al. , J .; Am. Chem. Soc. , 123, 4304 (2001), etc., a number of compounds are being studied for synthesis centering on heavy metal complexes such as iridium complexes.

  In addition, the aforementioned M.I. A. Baldo et al. , Nature, 403, 17, 750-753 (2000), studies have been made using tris (2-phenylpyridine) iridium as a dopant.

In addition, M.M. E. Thompson et al. In The 10th International Works on Inorganic and Organic Electroluminescence (EL'00, Hamamatsu) used L ₂ Ir (acac), for example, (ppy) ₂ Ir (acac) as a dopant, and MoY-J. 0 g, Tetsuo Tsutsui, etc. Again the The 10th International Workshop on Inorganic and Organic Electroluminescence (EL'00, Hamamatsu) in, as a dopant tris (2-(p-tolyl) pyridine) iridium (Ir (ptpy) _3), tris ( Studies using benzo [h] quinoline) iridium (Ir (bzq) ₃ ) and the like are being conducted (note that these metal complexes are generally called orthometalated iridium complexes).

  In addition, the S. Lamansky et al. , J .; Am. Chem. Soc. , 123, 4304 (2001), etc., attempts have been made to form devices using various iridium complexes.

  In order to obtain high luminous efficiency, The Kai et al. Use a hole-transporting compound as a host of a phosphorescent compound in The 10th International Works on Inorganic and Organic Electroluminescence (EL'00, Hamamatsu). In addition, M.M. E. Thompson et al. Use various electron transporting materials as phosphorescent compound hosts doped with a novel iridium complex.

  Orthometalated complexes in which the central metal is platinum instead of iridium are also attracting attention. With respect to this type of complex, many examples in which a ligand is characterized are known (for example, see Patent Documents 1 to 7).

  In any case, bidentate ligands and derivatives thereof, which are mainly bonded to the central metal by two coordination atoms, such as phenylpyridine, have been used as suitable examples of orthometalated complexes. However, the luminous brightness and luminous efficiency when these are used as light emitting elements are greatly improved compared to conventional elements because the emitted light is derived from phosphorescence. It is known to be lower than conventional devices.

In recent years, platinum complexes and iridium complexes using tridentate ligands having three coordination atoms have been reported. (See, for example, Patent Documents 8 to 10 and Non-Patent Document 1.) However, the light emission characteristics of these elements are still insufficient, and there has been development of elements using phosphorescent light-emitting materials with higher characteristics that can withstand practical use. It was desired.
JP 2001-181617 A JP 2001-247859 A JP 2002-332291 A JP 2002-332292 A JP 2002-338588 A JP 2002-226495 A JP 2002-234894 A JP 2003-73355 A International Publication No. 04/37981 Pamphlet International Publication No. 04/1008857 Pamphlet Inorganic Chemistry, Vol. 43, No. 21, pp. 6513-6515 (2004)

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an organic electroluminescent element material that exhibits high-efficiency light emission, has a long light emission lifetime, and is excellent in production yield, and an organic material using the same. Another object is to provide an electroluminescence element, and further a display device and an illumination device using the organic electroluminescence element.

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

(Claim 1)
An organic complex represented by the following general formula (1), wherein the tridentate ligand P ₁ or P ₂ has a substituent having 2 or more carbon atoms that suppress bidentate coordination: Electroluminescent element material.

(In the formula, M is a central metal. Tridentate ligands P ₁ and P ₂ are ligands bonded to the central metal M with three bonds, respectively, and P ₁ is represented by the following general formula (2). expressed.)

(In the formula, ring A, ring B and ring C are aromatic hydrocarbon rings or aromatic heterocyclic rings, and X, Y and Z constitute ring A, ring B and ring C, respectively, and are bonded to the central metal. At least one of which is a carbon atom, ring A-ring B and ring B-ring C are connected by L ₁ and L ₂ which are divalent linking groups. ₁ , R ₂ , and R ₃ are substituents, and may be further bonded to each other to form a ring, and n1, n2, and n3 are 0 or an integer of 1 or more.

(Claim 2)
The material for an organic electroluminescence device according to claim 1, wherein the tridentate ligand P ₁ or P ₂ has a substituent having a van der Waals volume of 45 ³ or more.

(Claim 3)
The material for an organic electroluminescent element according to claim 1, wherein the tridentate ligand P ₂ is represented by the general formula (2).

(Claim 4)
In Formula (2) The organic electroluminescent device according to claim 1, wherein at least one of the substituents R ₂ of the B ring is van der Waals volume of 45 Å ³ or more Materials.

(Claim 5)
The material for an organic electroluminescence device according to claim 1, wherein the tridentate ligand P ₂ is represented by the following general formula (3).

(In the formula, ring A, ring B and ring C are aromatic hydrocarbon rings or aromatic heterocyclic rings, and X, Y and Z constitute ring A, ring B and ring C, respectively, and are bonded to the central metal. Or at least one is a carbon atom, ring A-ring B, ring B-ring C are directly bonded, R ₁ , R ₂ , R ₃ are substituents And may be bonded to each other to form a ring, and n1, n2, and n3 are 0 or an integer of 1 or more.)

(Claim 6)
In Formula (3), material for an organic electroluminescence device according to claim 5, wherein at least one of the substituents R ₂ of the B ring is van der Waals volume of 45 Å ³ or more.

(Claim 7)
The material for an organic electroluminescent element according to any one of claims 1 to 6, wherein the metal complex represented by the general formula (1) is a part of a main chain or a side chain of a polymer. .

(Claim 8)
The organic electroluminescent element material according to claim 1, wherein the central metal M is selected from Ir, Rh, and Os.

(Claim 9)
The organic electroluminescent element which contains the organic electroluminescent element material of any one of Claims 1-8 in any of a structural layer.

(Claim 10)
The organic electroluminescent element according to claim 9, wherein one of the constituent layers is a light emitting layer.

(Claim 11)
The organic electroluminescent device according to claim 9 or 10, wherein a carbazole derivative is contained in at least one of the constituent layers.

(Claim 12)
The organic electroluminescent element according to claim 9 or 10, wherein a compound represented by the following general formula (A) is contained in at least one of the constituent layers.

(Wherein Z ₁ represents an atomic group forming an aromatic heterocyclic ring, Z ₂ represents an atomic group forming an aromatic heterocyclic ring or an aromatic hydrocarbon ring, and Z ₃ represents a divalent linking group or .R ₁₀₁ representing the bond represents a hydrogen atom or a substituent.)
(Claim 13)
A display device comprising the organic electroluminescence element according to claim 9.

(Claim 14)
It has an organic electroluminescent element of any one of Claims 9-12, The illuminating device characterized by the above-mentioned.

  INDUSTRIAL APPLICABILITY According to the present invention, a material for an organic electroluminescence element that exhibits high-efficiency light emission, has a long emission lifetime, and has an excellent production yield, an organic electroluminescence element using the material, and a display device using the organic electroluminescence element We were able to provide a lighting device.

  The material for an organic electroluminescence element of the present invention (hereinafter also referred to as an organic EL element material) has a completed structure by having two tridentate ligands that can be bound in a tridentate with a six-coordinate central metal. It is characterized by that. Such tridentate ligands have more bonds with the central metal of the ligand than conventional bidentate ligands such as phenylpyridine, so energy transfer between metal and ligand Becomes easy, and highly efficient light emission becomes possible. Furthermore, a larger stabilization energy accompanying complex formation can be obtained.

  In the present invention, the structure defined in any one of claims 9 to 12 using the organic EL device material according to any one of claims 1 to 8 exhibits high luminous efficiency, and has a luminous lifetime. A long organic EL element could be obtained.

As a result of intensive studies on the above-mentioned problems, the present inventors have replaced hexadentate ligands that have been studied in various fields so far, and have six-coordination as represented by the general formula (1). It has been found that by using a metal complex having a completed structure with a central metal and two tridentate ligands, a material for an organic EL device can be provided that has high luminous efficiency and has a significantly improved luminous lifetime. The material for an organic EL device of the present invention has a substituent having 2 or more carbon atoms that suppresses bidentate coordination to at least one of the tridentate ligands P ₁ or P ₂ , or a van der Waals volume of 45 ³ or more. It has at least one substituent. In the substituent having 2 or more carbon atoms that suppress bidentate coordination, the substituent is preferably up to 20 carbon atoms. By having such a bulky substituent, the metal coordination selectivity is improved, and the target metal complex can be synthesized with high yield.

More preferably 45～400A ³ as the van der Waals volume of this time the substituent, more preferably 45～250A ^3, and most preferably 45~150Å ^3.

  In addition, at least one of the tridentate ligands forming the metal complex has a structure of the general formula (2). The tridentate ligand has three ring structures of ring A, ring B, and ring C, and these are preferably aromatic hydrocarbon rings or aromatic heterocyclic rings, and particularly ring B is a 6-membered ring. More preferably, it has a structure.

  The ligand represented by the general formula (2) preferably has at least one substituent on ring A, ring B, and ring C, and more preferably has a substituent on ring B.

  The central metal is not particularly limited as long as it can emit phosphorescence, but is preferably a metal included in Groups 8 to 11 in the periodic table, and is selected from Ir, Os, Rh, Pt, and Zn. More preferably, any one is selected, and most preferably selected from Ir, Os, and Rh.

  The organic EL device material of the present invention may have a counter ion, but is more preferably neutral as a whole.

  In addition, the constituent layer containing the organic EL element material of the present invention is preferably formed by coating for the purpose of simplifying the preparation of the organic EL element, increasing the area of the element, and reducing the price. More preferably, the complex is part of the main chain or side chain of the polymer.

  In addition, the organic EL device material of the present invention is preferably used in the light emitting layer among the constituent layers of the organic EL device, and more preferably used as a dopant in the light emitting layer. Appropriate combinations with other organic layer materials such as the electron transport layer, hole transport layer, and light-emitting host used at this time enable higher brightness, more efficient light emission, and longer device life. It is. From such a viewpoint, it is preferable to use the compound represented by the general formula (1) in at least one layer of the organic layer, and it is more preferable to use the general formula (A) as a light emitting host and / or a hole blocking material. .

  The van der Waals (VDW) volume of the substituent in the present invention is a parameter determined using the molecular simulation software Cerius 2 manufactured by Accelrys, Inc., but a substituent is introduced into the benzene ring, and using the Driving Force Field, The molecular structure is optimized by MM calculation, and is defined as a Volume value obtained using the Connoy Surface. Specific van der Waals (VDW) volumes of substituents are shown below.

Substituent Å ³
Methyl group 25.4
Ethyl group 42.6
Isopropyl group 59.5
tert-Butyl group 76.2
Phenyl group 74.9
Methoxy group 34.0
Amino group 22.2
Hydroxyl group 16.7
Chlorine atom 22.4
Bromine atom 26.5
Fluorine atom 13.3
Trifluoromethyl group 42.5
Therefore, specific examples of the substituent having a van der Waals volume of 45 ³ or more include an isopropyl group, a tert-butyl group, and a phenyl group.

In the general formula (2), ring A, ring B, and ring C are aromatic hydrocarbon rings or aromatic heterocycles, X, Y, and Z are carbon atoms or nitrogen atoms, and at least one is a carbon atom. However, it is bonded to the central metal M of Groups 8 to 11. Ring A-ring B and ring B-ring C are connected by a divalent linking group represented by L ₁ and L ₂ , respectively. R ₁ , R ₂ and R ₃ are substituents, and may be bonded to each other to form a ring. n1, n2, and n3 are 0 or an integer of 1 or more.

Specific examples of the aromatic hydrocarbon ring represented by ring A, ring B, and ring C include benzene ring, biphenyl ring, naphthalene ring, azulene ring, anthracene ring, phenanthrene ring, pyrene ring, chrysene ring, naphthacene ring, triphenylene Ring, o-terphenyl ring, m-terphenyl ring, p-terphenyl ring, acenaphthene ring, coronene ring, fluorene ring, fluoranthrene ring, naphthacene ring, pentacene ring, perylene ring, pentaphen ring, picene ring, pyrene Ring, pyranthrene ring, anthraanthrene ring and the like. Specific examples of the aromatic heterocycle represented by ring A, ring B, and ring C include a furan ring, a thiophene ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, a benzimidazole ring, and an oxadiazole. Ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indole ring, benzimidazole ring, benzothiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring, phthalazine ring, carbazole ring, carboline ring, diazacarbazole ring (carboline) A ring in which one of the carbon atoms of the hydrocarbon ring constituting the ring is further substituted with a nitrogen atom). These may be further substituted with a substituent represented by R ₁₀₁ in formula (A), which will be described later.

The divalent linking group represented by L ₁ and L ₂ may be a hydrocarbon group such as alkylene, alkenylene, alkynylene, arylene, etc., and may contain a hetero atom, and a thiophene-2,5-diyl group. Or a divalent linking group derived from a compound having an aromatic heterocycle (also called a heteroaromatic compound) such as a pyrazine-2,3-diyl group, or a chalcogen atom such as oxygen or sulfur. There may be. Moreover, the group which connects and connects hetero atoms, such as an alkylimino group, a dialkylsilane diyl group, and a diaryl germane diyl group, may be sufficient.

R ₁ , R ₂ and R ₃ are substituents, and at least one of them is a substituent having 2 or more carbon atoms that suppresses bidentate coordination or a substituent having a van der Waals volume of 45 ³ or more. Among the substituents of R ₁ , R ₂ , and R ₃ , examples of the substituent that has 2 or more carbon atoms that suppress bidentate coordination or the above-mentioned substituent that has a van der Waals volume of 45 to ³ or more are as follows. Appropriate substituents represented by R ₁₀₁ in the formula (A), for example, a halogen atom, a cyano group, a hydroxyl group, a methyl group, a trifluoromethyl group and the like can be mentioned.

In Formula (3), X, Y, Z, R 1, R 2, R 3, n1, n2, n3 have the same meanings as those in the general formula (2).

  Illustrative compounds of the metal complex represented by the general formula (1) are shown below.

  These compounds are described, for example, in Journal of the Chemical Society, Dalton Transactions, 1477 (1987), Inorganic Chemistry 43, 6513 (2004) and Organometallics 18, 3337 (1999) as a reference. Can be synthesized.

<< Application of organic EL element materials to organic EL elements >>
When producing an organic EL element using the organic EL element material of the present invention, it is preferably used for a light emitting layer or a hole blocking layer in the constituent layers (details will be described later) of the organic EL element. In the light emitting layer, as described above, it is preferably used as a light emitting dopant.

(Light emitting host and light emitting dopant)
The mixing ratio of the light-emitting dopant to the light-emitting host, which is the host compound as the main component in the light-emitting layer, is preferably adjusted to a range of 0.1 to less than 30% by mass.

  However, the light-emitting dopant may be a mixture of a plurality of types of compounds, and the partner to be mixed may be a phosphorescent dopant or a fluorescent dopant having a different structure, other metal complexes or other structures.

  Here, the dopant (phosphorescent dopant, fluorescent dopant, etc.) that may be used in combination with the platinum complex used as the luminescent dopant will be described. The light-emitting dopant is roughly classified into two types: a fluorescent dopant that emits fluorescence and a phosphorescent dopant that emits phosphorescence.

  Representative examples of the former (fluorescent dopant) include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes, Examples include perylene dyes, stilbene dyes, polythiophene dyes, and rare earth complex phosphors.

  Typical examples of the latter (phosphorescent dopant) are preferably complex compounds containing metals of Group 8, Group 10, and Group 10 in the periodic table of elements, more preferably iridium compounds and osmium compounds, Of these, iridium compounds are the most preferred.

  Specifically, it is a compound described in the following patent publications.

  WO 00/70655 pamphlet, JP 2002-280178, JP 2001-181616, JP 2002-280179, JP 2001-181617, JP 2002-280180, JP 2001-247859, JP 2002-299060, JP 2001-313178, JP 2002-302671, JP 2001-345183, JP 2002-324679, International Publication No. 02/15645 pamphlet, 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 20 JP-A-2-338588, JP-A-2002-170684, JP-A-2002-352960, WO01 / 93642, JP-A-2002-50483, JP-A-2002-1000047, JP-A-2002. No. -173744, JP-A No. 2002-359082, JP-A No. 2002-17584, JP-A No. 2002-363552, JP-A No. 2002-184582, JP-A No. 2003-7469, JP-T-2002-525808. Gazette, JP2003-7471, JP2002-525833, JP2003-31366, JP2002-226495, JP2002-234894, JP2002-2335076 JP 2002-241751 A JP 2001-319779, JP 2001-319780, JP 2002-62824, JP 2002-1000047, JP 2002-203679, JP 2002-343572, JP 2002-203678 gazette etc.

  Some examples are shown below.

(Light emitting host)
A light-emitting host (also simply referred to as a host) means a compound having the largest mixing ratio (mass) in a light-emitting layer composed of two or more compounds. For other compounds, “dopant compound ( Simply referred to as a dopant). " For example, if the light emitting layer is composed of two types of compound A and compound B and the mixing ratio is A: B = 10: 90, compound A is a dopant compound and compound B is a host compound. Further, if the light emitting layer is composed of three types of compound A, compound B and compound C and the mixing ratio is A: B: C = 5: 10: 85, compound A and compound B are dopant compounds, and compound C is a host compound.

  As the luminescent host used in the present invention, a compound having a wavelength shorter than the phosphorescence 0-0 band of the luminescent dopant used in combination is preferable, and the phosphorescent 0-0 band is 480 nm or less as the luminescent dopant. In the case of using a compound containing the above light emitting component, the phosphorescent 0-0 band is preferably 450 nm or less as the light emitting host.

  The light emitting host according to the present invention is not particularly limited in terms of structure, but is typically a carbazole derivative, a triarylamine derivative, an aromatic borane derivative, a nitrogen-containing heterocyclic compound, a thiophene derivative, a furan derivative, an oligoarylene. A compound having a basic skeleton such as a compound and having the 0-0 band of 450 nm or less is preferred. The light emitting host according to 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).

  As the light-emitting host, a compound having a hole transporting ability and an electron transporting ability, preventing a long wavelength of light emission, and having a high Tg (glass transition temperature) is preferable.

  As specific examples of the light-emitting host, compounds described in the following documents are suitable. For example, Japanese Patent Laid-Open Nos. 2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, JP2002-8860, JP2002-334787, JP2002-15871, JP2002-334788, JP2002-43056, JP2002-334789, JP JP 2002-75645 A, JP 2002-338579 A, JP 2002-105445 A, JP 2002-343568 A, JP 2002-141173 A, JP 2002-352957 A, JP 2002-2002 A. No. 203683, JP-A-2002-3632 7, JP 2002-231453, JP 2003-3165, JP 2002-234888, JP 2003-27048, JP 2002-255934, JP 2002-286061. JP, JP-A-2002-280183, JP-A-2002-299060, JP-A-2002-302516, JP-A-2002-305083, JP-A-2002-305084, JP-A-2002-308837, etc. .

  Next, a configuration of a typical organic EL element will be described.

<< Constituent layers of organic EL elements >>
The constituent layers of the organic EL element of the present invention will be described.

Although the preferable specific example of the layer structure of the organic EL element of this invention 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 << light emitting layer >>
In the present invention, the organic EL device material of the present invention is preferably used in the light emitting layer, but in addition to these, a known light emitting host or light emitting dopant as described above may be used in combination.

  Here, it is preferable that the light emitting layer contains the compound represented by the general formula (A) from the viewpoint of further improving the effects described in the present invention (improvement of light emission luminance and extension of light emission lifetime). These compounds are preferably used as a light emitting host in the light emitting layer.

In the general formula (A), Z ₁ represents an atomic group forming an aromatic heterocyclic ring which may have a substituent, and Z ₂ represents an aromatic heterocyclic ring which may have a substituent, or aromatic It represents an atomic group forming a hydrocarbon ring, and Z ₃ represents a divalent linking group or a simple bond. R ₁₀₁ represents a hydrogen atom or a substituent.

Examples of the aromatic heterocycle represented by the atomic group of Z ₁ and Z ₂ include a furan ring, a thiophene ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, a benzimidazole ring, an oxadiazole ring, and a triazole. Ring, imidazole ring, pyrazole ring, thiazole ring, indole ring, benzimidazole ring, benzothiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring, phthalazine ring, carbazole ring, carboline ring, diazacarbazole ring (composing carboline ring) A ring in which one of the carbon atoms of the hydrocarbon ring is further substituted with a nitrogen atom). Further, the aromatic heterocyclic ring may have a substituent represented by R ₁₀₁ described later.

Examples of the aromatic hydrocarbon ring represented by the Z ₂ atom group include a benzene ring, a biphenyl ring, a naphthalene ring, an azulene ring, an anthracene ring, a phenanthrene ring, a pyrene ring, a chrysene ring, a naphthacene ring, a triphenylene ring, and an o-tell. Phenyl ring, m-terphenyl ring, p-terphenyl ring, acenaphthene ring, coronene ring, fluorene ring, fluoranthrene ring, naphthacene ring, pentacene ring, perylene ring, pentaphen ring, picene ring, pyrene ring, pyranthrene ring, Anthraanthrene rings and the like can be mentioned. Further, the aromatic hydrocarbon ring may have a substituent represented by R ₁₀₁ described later.

Examples of the substituent represented by R ₁₀₁ include an alkyl group (for example, methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group). , Pentadecyl group etc.), cycloalkyl group (eg cyclopentyl group, cyclohexyl group etc.), alkenyl group (eg vinyl group, allyl group etc.), alkynyl group (eg ethynyl group, propargyl group etc.), aryl group (eg , Phenyl group, naphthyl group, etc.), aromatic heterocyclic group (for example, furyl group, thienyl group, pyridyl group, pyridazinyl group, pyrimidinyl group, pyrazinyl group, triazinyl group, imidazolyl group, pyrazolyl group, thiazolyl group, quinazolinyl group, Phthalazinyl group, etc.), heterocyclic group (eg, pyrrolidyl group, imi Dazolidyl group, morpholyl group, oxazolidyl group, etc.), alkoxyl group (for example, methoxy group, ethoxy group, propyloxy group, pentyloxy group, hexyloxy group, octyloxy group, dodecyloxy group, etc.), cycloalkoxyl group (for example, Cyclopentyloxy group, cyclohexyloxy group, etc.), aryloxy group (eg, phenoxy group, naphthyloxy group, etc.), alkylthio group (eg, methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group) Etc.), cycloalkylthio group (eg, cyclopentylthio group, cyclohexylthio group, etc.), arylthio group (eg, phenylthio group, naphthylthio group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, etc.) Ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (eg, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), sulfamoyl group (eg, aminosulfonyl group, Methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group Etc.), acyl group (for example, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group) Octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy group (for example, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group) Group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide group (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2 -Ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc. ), Carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylamino) Carbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), ureido group (for example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido group, dodecylureido group, Phenylureido group naphthylureido group, 2-pyridylaminoureido group, etc.), sulfinyl group (for example, methylsulfinyl group, ethylsulfinyl group, butyl) Rufinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group, etc.), alkylsulfonyl group (for example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group) Cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc.), arylsulfonyl group (eg, phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (eg, amino group, ethylamino group) Dimethylamino group, butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, naphthylamino group, 2-pyridylamino group, etc.) Halogen atom (for example, fluorine atom, chlorine atom, bromine atom, etc.), fluorinated hydrocarbon group (for example, fluoromethyl group, trifluoromethyl group, pentafluoroethyl group, pentafluorophenyl group, etc.), cyano group, nitro group , Hydroxyl group, mercapto group, silyl group (for example, trimethylsilyl group, triisopropylsilyl group, triphenylsilyl group, phenyldiethylsilyl group, etc.).

  These substituents may be further substituted with the above substituents. In addition, a plurality of these substituents may be bonded to each other to form a ring. Preferred substituents are an alkyl group, a cycloalkyl group, a fluorinated hydrocarbon group, an aryl group, and an aromatic heterocyclic group.

  Examples of the divalent linking group may include hydrocarbon groups such as alkylene, alkenylene, alkynylene, and arylene, and those containing a hetero atom, and also include a thiophene-2,5-diyl group, pyrazine-2,3- It may be a divalent linking group derived from a compound having an aromatic heterocycle such as a diyl group (also referred to as a heteroaromatic compound), or may be a chalcogen atom such as oxygen or sulfur. Moreover, the group which connects and connects hetero atoms, such as an alkylimino group, a dialkylsilane diyl group, and a diaryl germane diyl group, may be sufficient.

  A mere bond is a bond that directly bonds the connecting substituents together.

In the present invention, the ring formed by Z _{1 in the} general formula (A) is preferably a 6-membered ring. Thereby, luminous efficiency can be made higher. Further, the life can be extended. In the present invention, the ring formed by Z ₂ is preferably a 6-membered ring. Thereby, luminous efficiency can be made higher. Further, the lifetime can be further increased. Furthermore, it is preferable that both Z ₁ and Z ₂ are 6-membered rings because the luminous efficiency can be further increased. Further, it is preferable because the lifetime can be further increased.

  Specific examples of the compound represented by formula (A) according to the present invention are shown below, but the present invention is not limited thereto.

  The light emitting layer according to the present invention can be formed by forming the above compound by a known thinning method such as a vacuum deposition method, a spin coating method, a casting method, or an LB method. Although the film thickness as a light emitting layer does not have a restriction | limiting in particular, Usually, it selects in 5 nm-5 micrometers. This light emitting layer may have a single layer structure composed of one or two or more of these light emitting materials, or may have a laminated structure composed of a plurality of layers having the same composition or different compositions.

  In addition, as described in JP-A-57-51781, this light-emitting layer is prepared by dissolving the above light-emitting material in a solvent together with a binder such as a resin to form a thin film by spin coating or the like. Can be formed. There is no restriction | limiting in particular about the film thickness of the light emitting layer formed in this way, Although it can select suitably according to a condition, Usually, it is the range of 5 nm-5 micrometers.

《Blocking layer (electron blocking layer, hole blocking layer)》
The blocking layer (for example, electron blocking layer, hole blocking layer) according to the present invention will be described. The thickness of the blocking layer according to the present invention is preferably 3 to 100 nm, and more preferably 5 to 30 nm.

《Hole blocking layer》
The hole blocking layer has the function of an electron transport layer in a broad sense, and is made of a material that has a function of transporting electrons but has a very small ability to transport holes, and blocks holes while transporting electrons. Thus, the probability of recombination of electrons and holes can be improved.

  In the present invention, the organic EL device material of the present invention can be preferably used for the hole blocking layer in an adjacent layer adjacent to the light emitting layer, for example, a hole blocking layer, an electron blocking layer or the like.

  Examples of the hole blocking layer include, for example, JP-A Nos. 11-204258 and 11-204359, and “Organic EL elements and the forefront of industrialization thereof (issued by NTT Corporation on November 30, 1998)” Can be applied as the hole blocking layer according to the present invention. Moreover, the structure of the electron carrying layer mentioned later can be used as a hole-blocking layer concerning this invention as needed.

  The hole blocking layer according to the present invention preferably contains a compound represented by the general formula (A). The hole blocking layer according to the present invention preferably contains a boron derivative.

《Electron blocking layer》
On the other hand, the electron blocking layer has a function of a hole transport layer in a broad sense, and is made of a material that has a function of transporting holes and has an extremely small ability to transport electrons, and transports electrons while transporting holes. By blocking, the recombination probability of electrons and holes can be improved. Moreover, the structure of the positive hole transport layer mentioned later can be used as an electron blocking layer as needed.

  In the present invention, the organic EL device material of the present invention is preferably used for the adjacent layer adjacent to the light emitting layer, that is, the hole blocking layer and the electron blocking layer, and particularly used for the hole blocking layer. Is preferred.

《Hole transport layer》
The hole transport layer includes a 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.

  There are no particular restrictions on the hole transport material, and conventionally known photoconductive materials are commonly used as hole charge injection and transport materials, and well-known materials used for hole injection layers and hole transport layers of EL devices. Any one can be selected and used.

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

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

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

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used. In addition, inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material. In the present invention, the hole transport material of the hole transport layer preferably has a fluorescence maximum wavelength at 415 nm or less, and more preferably has a 0-0 band of phosphorescence of 450 nm or less. Further, the hole transport material preferably has a high Tg.

  This hole transport layer can be formed by thinning the hole transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, an ink jet method, or an LB method. Although there is no restriction | limiting in particular about the film thickness of a positive hole transport layer, Usually, it is about 5-5000 nm. The hole transport layer may have a single layer structure composed of one or more of the above materials.

《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.

  Conventionally, in the case of a single-layer electron transport layer and a plurality of layers, the following materials are used as the electron transport material (also serving as a hole blocking material) used for the electron transport layer adjacent to the cathode side with respect to the light emitting layer. Are known. Further, the electron transport layer only needs to have a function of transmitting electrons injected from the cathode to the light emitting layer, and any material can be selected and used from conventionally known compounds.

  Examples of materials used for this 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, carbodiimides, Examples include fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, and oxadiazole derivatives. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material.

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

  In addition, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq), 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 metal of these metal complexes is 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 terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transport material. In addition, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as an electron transport material, and similarly to the hole injection layer and the hole transport layer, inorganic such as n-type-Si and n-type-SiC. A semiconductor can also be used as an electron transport material.

  This electron transport layer can be formed by thinning the electron transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, an ink jet method, or an LB method. Although there is no restriction | limiting in particular about the film thickness of an electron carrying layer, Usually, it is about 5-5000 nm. This electron transport layer may have a single layer structure composed of one or more of the above materials.

  Next, an injection layer used as a constituent layer of the organic EL element of the present invention will be described.

<< Injection Layer >>: Electron Injection Layer, Hole Injection Layer An injection layer is provided as necessary, and includes an electron injection layer and a hole injection layer, and as described above, between the anode and the light emitting layer or the hole transport layer, and the cathode. Between the light emitting layer and the electron transport layer.

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

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

  The details of the cathode buffer layer (electron injection layer) are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Specifically, strontium, aluminum, etc. Metal buffer layer typified by lithium, alkali metal compound buffer layer typified by lithium fluoride, alkaline earth metal compound buffer layer typified by magnesium fluoride, oxide buffer layer typified by aluminum oxide, etc. .

  The buffer layer (injection layer) is preferably a very thin film, and the film thickness is preferably in the range of 0.1 to 100 nm although it depends on the material.

  This injection layer can be formed by thinning the above material by a known method such as a vacuum deposition method, a spin coating method, a casting method, an ink jet method, or an LB method. Although there is no restriction | limiting in particular about the film thickness of an injection | pouring layer, Usually, it is about 5-5000 nm. The injection layer may have a single layer structure composed of one or more of the above materials.

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

"cathode"
On the other hand, as the cathode according to the present invention, a cathode having a work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among these, from the point of durability against electron injection and oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than this, for example, a magnesium / silver mixture, Suitable are a magnesium / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide (Al ₂ O ₃ ) mixture, a lithium / aluminum mixture, aluminum and the like. The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 to 1000 nm, preferably 50 to 200 nm. In order to transmit light, if either one of the anode or the cathode of the organic EL element is transparent or translucent, the light emission luminance is improved, which is convenient.

<< Substrate (also referred to as substrate, substrate, support, etc.) >>
The substrate of the organic EL device of the present invention is not particularly limited as to the type of glass, plastic and the like, and is not particularly limited as long as it is transparent. Examples of the substrate preferably used include glass and quartz. And a light transmissive resin film. A particularly preferable substrate is a resin film that can give flexibility to the organic EL element.

  Examples of the resin film include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyetherimide, polyetheretherketone, polyphenylene sulfide, polyarylate, polyimide, polycarbonate (PC), and cellulose. Examples include films made of triacetate (TAC), cellulose acetate propionate (CAP), and the like.

An inorganic or organic film or a hybrid film of both may be formed on the surface of the resin film, and the film should be a high barrier film having a water vapor transmission rate of 0.01 g / m ² · day · atm or less. preferable.

  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 2% or more. Here, the external extraction quantum efficiency (%) = the number of photons emitted to the outside of the organic EL element / the number of electrons sent to the organic EL element × 100.

  Further, a hue improving filter such as a color filter may be used in combination.

  When used in lighting applications, a film (such as an antiglare film) that has been roughened to reduce unevenness in light emission can be used in combination.

  When used as a multicolor display device, it is composed of organic EL elements having at least two different light emission maximum wavelengths. A suitable example for producing an organic EL element will be described.

<< Method for producing organic EL element >>
As an example of the method for producing the organic EL device of the present invention, 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 / cathode buffer layer / cathode. Will be described.

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

As described above, the thinning method of a thin film containing an organic compound includes a spin coating method, a casting method, an ink jet method, a vapor deposition method, a printing method, and the like. From the viewpoint of difficulty in formation, the vacuum deposition method or the spin coating method is particularly preferable. Further, a different film forming method may be applied for each layer. When employing a vapor deposition method for film formation, the vapor deposition conditions vary depending on the type of compound used, but generally a boat heating temperature of 50 to 450 ° C., a vacuum degree of 10 ⁻⁶ to 10 ⁻² Pa, and a vapor deposition rate of 0.01 It is desirable to select appropriately within a range of ˜50 nm / second, a substrate temperature of −50 to 300 ° C., and a film thickness of 0.1 nm to 5 μm.

  After the formation of these layers, a thin film made of a cathode material is formed thereon by a method such as vapor deposition or sputtering so as to have a thickness of 1 μm or less, preferably in the range of 50 nm to 200 nm, and a cathode is provided. Thus, a desired organic EL element can be obtained. The organic EL element is preferably produced from the hole injection layer to the cathode consistently by a single evacuation, but may be taken out halfway and subjected to different film forming methods. At that time, it is necessary to consider that the work is performed in a dry inert gas atmosphere.

<Display device>
The display device of the present invention will be described.

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

  In the case of patterning only the light emitting layer, the method is not limited, but the vapor deposition method, the ink jet method, and the printing method are preferable. In the case of using a vapor deposition method, patterning using a shadow mask is preferable.

  Moreover, it is also possible to reverse the production order to produce the cathode, the electron transport layer, the hole blocking layer, the light emitting layer, the hole transport layer, and the anode in this 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 to 40 V with the positive polarity of the anode and the negative polarity of the cathode. Further, even when a voltage is applied with the opposite polarity, no current flows and no light emission occurs. Further, when an AC voltage is applied, light is emitted only when the anode is in the + state and the cathode is in the-state. The alternating current waveform to be applied may be arbitrary.

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

  Examples of the display device and the display include a television, a personal computer, a mobile device, an AV device, a character broadcast display, and an information display in a car. 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. For example, but not limited to.

《Lighting device》
The lighting device of the present invention will be described.

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

  Further, the organic EL element of the present invention may be used as a kind of lamp for illumination or exposure light source, a projection device for projecting an image, or a type for directly viewing a still image or a moving image. It may be used as a display device (display). When used as a display device for reproducing moving images, the driving method may be either a simple matrix (passive matrix) method or an active matrix method. Alternatively, a full-color display device can be produced by using two or more organic EL elements of the present invention having different emission colors.

  An example of a display device composed of the organic EL element of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram illustrating an example of a display device including organic EL elements. It is a schematic diagram of a display such as a mobile phone that displays image information by light emission of an organic EL element.

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

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

  FIG. 2 is a schematic diagram of the display unit A.

  The display unit A includes a wiring unit including a plurality of scanning lines 5 and data lines 6, a plurality of pixels 3 and the like on a substrate. The main members of the display unit A will be described below. FIG. 2 shows a case where the light emitted from the pixel 3 is extracted in the direction of the white arrow (downward).

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

  When a scanning signal is applied from the scanning line 5, the pixel 3 receives an image data signal from the data line 6 and emits light according to the received image data. Full color display is possible by appropriately arranging pixels in the red region, the green region, and the blue region that emit light on the same substrate.

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

  FIG. 3 is a schematic diagram of a pixel.

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

  In FIG. 3, an image data signal is applied from the control unit B to the drain of the switching transistor 11 through the data line 6. When a scanning signal is applied from the control unit B to the gate of the switching transistor 11 via the scanning line 5, the driving of the switching transistor 11 is turned on, and the image data signal applied to the drain is supplied to the capacitor 13 and the driving transistor 12. Is transmitted to the gate.

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

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

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

  Here, the light emission of the organic EL element 10 may be light emission of a plurality of gradations by a multi-value image data signal having a plurality of gradation potentials, or on / off of a predetermined light emission amount by a binary image data signal. But you can.

  The potential of the capacitor 13 may be held continuously until the next scanning signal is applied, or may be discharged immediately before the next scanning signal is applied.

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

  FIG. 4 is a schematic diagram of a passive matrix display device. In FIG. 4, a plurality of scanning lines 5 and a plurality of image data lines 6 are provided in a lattice shape so as to face each other with the pixel 3 interposed therebetween.

  When the scanning signal of the scanning line 5 is applied by sequential scanning, the pixels 3 connected to the applied scanning line 5 emit light according to the image data signal. In the passive matrix system, the pixel 3 has no active element, and the manufacturing cost can be reduced.

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

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

  As a layer structure of the organic EL element for obtaining a plurality of emission colors, a method of having a plurality of emission dopants in one emission layer, a plurality of emission layers, and an emission wavelength of each emission layer. Examples thereof include a method in which different dopants are present, and a method in which minute pixels that emit light at different wavelengths are formed in a matrix.

  In the white organic EL element concerning this invention, you may pattern by a metal mask, an inkjet printing method, etc. at the time of film forming as needed. When patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or the entire element layer may be patterned.

  The light emitting material used for the light emitting layer is not particularly limited. For example, in the case of a backlight in a liquid crystal display element, the platinum complex according to the present invention is adapted so as to be adapted to the wavelength range corresponding to the CF (color filter) characteristics, Any one of known luminescent materials may be selected and combined to whiten.

  As described above, in addition to the display device and the display, the white light-emitting organic EL element is used as a light-emitting light source and a lighting device as a lamp for home lighting, vehicle interior lighting, and an exposure light source. It is also useful for display devices such as backlights.

  Others such as backlights for watches, signboard 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. There are a wide range of uses such as household appliances.

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

Example 1
<< Production of Organic EL Element-1 >>
After patterning on a substrate (made by NH Techno Glass Co., Ltd .: NA-45) having a 150 nm ITO film formed on glass as an anode, the transparent support substrate provided with this ITO transparent electrode was ultrasonically cleaned with iso-propyl alcohol. The sample was dried with dry nitrogen gas, and UV ozone cleaning was performed for 5 minutes. The transparent support substrate is fixed to a substrate holder of a commercially available vacuum deposition apparatus, while α-NPD, CBP, Ir-11, BCP, and Alq ₃ are placed in five tantalum resistance heating boats, respectively. (First vacuum chamber).

  Further, lithium fluoride was put into a resistance heating boat made of tantalum, and aluminum was put into a resistance heating boat made of tungsten, respectively, and attached to the second vacuum tank of the vacuum evaporation apparatus.

First, after reducing the pressure of the first vacuum tank to 4 × 10 ⁻⁴ Pa, the heating boat containing α-NPD was energized and heated, and the transparent support substrate was deposited at a deposition rate of 0.1 to 0.2 nm / second. The film was deposited to a thickness of 25 nm to provide a hole injection / transport layer.

  Further, the heating boat containing CBP and the boat containing Ir-11 are energized independently to adjust the deposition rate of CBP as a light emitting host and Ir-11 as a light emitting dopant to 100: 7. Vapor deposition was performed to a thickness of 30 nm to provide a light emitting layer.

Next, the heating boat containing BCP was energized and heated to provide a 10 nm thick hole blocking layer at a deposition rate of 0.1 to 0.2 nm / sec. Further, the heating boat containing Alq ₃ was energized and heated to provide an electron transport layer having a film thickness of 40 nm at a deposition rate of 0.1 to 0.2 nm / second.

  Next, the element formed up to the electron transport layer as described above is transferred to the second vacuum chamber while being vacuumed, and then remotely from the outside of the apparatus so that a stainless steel rectangular perforated mask is disposed on the electron transport layer. Controlled and installed.

After depressurizing the second vacuum tank to 2 × 10 ⁻⁴ Pa, a cathode buffer layer having a film thickness of 0.5 nm was provided at a deposition rate of 0.01 to 0.02 nm / second by energizing a boat containing lithium fluoride. Next, a boat containing aluminum was energized to attach a cathode having a film thickness of 150 nm at a deposition rate of 1 to 2 nm / second to produce an organic EL element OLED1-1.

<< Preparation of organic EL elements-2 to -15 >>
In the production of the organic EL element-1, organic EL elements-2 to -15 were produced in the same manner except that the light emitting dopant, the light emitting host, and the hole blocking material were changed as shown in Table 1.

  The obtained organic EL elements-1 to -15 were evaluated as follows.

<< External quantum efficiency >>
The organic EL elements -1 to -15 are lit at room temperature (about 23 to 25 ° C.) under a constant current condition of ^2.5 mA / cm ² , and the light emission luminance (L) [cd / m ² ] immediately after the lighting is started. The external extraction quantum efficiency (η) was calculated by measuring. Here, CS-1000 (manufactured by Konica Minolta) was used for measurement of light emission luminance. The external extraction quantum efficiency was expressed as a relative value when the organic EL element-1 was 100.

<Luminescent life>
The organic EL elements -1 to -15 were continuously lit at a constant current of ^2.5 mA / cm ² at room temperature, and the time (τ _1/2 ) required to reach half the initial luminance was measured. . Moreover, the light emission lifetime was represented by the relative value when the organic EL element-1 was set to 100.

  The obtained results are shown in Table 1.

  From Table 1, it is clear that the organic EL device of the present invention has high emission efficiency and excellent emission lifetime. In addition, it is clear that the organic EL device of the present invention has higher luminous efficiency and excellent emission lifetime by using the compound represented by the general formula (A) for the light emitting host or hole blocking material.

Example 2
<< Production of white organic EL element and lighting device by coating >>
An anode of indium tin oxide (ITO, indium / tin = 95/5 molar ratio) was formed on a glass support substrate of 25 mm × 25 mm × 0.5 mm by a sputtering method using a direct current power (thickness: 200 nm). The surface resistance of this anode was 10Ω / □. Polyvinylcarbazole (hole transporting binder polymer) / present compound 1 / present compound 6 / present compound 10 / 2- (4-biphenylyl) -5- (4-t-butylphenyl) -1,3 , 4-oxadiazole (electron transport material) = 200/2/3/2/50 A dichloroethane solution in which a mass ratio was dissolved was applied by a spin coater to obtain a light-emitting layer having a thickness of 100 nm.

  A patterned mask (a mask with a light emission area of 5 mm × 5 mm) is placed on the organic compound layer, and 0.5 nm of lithium fluoride is deposited as a cathode buffer layer and 150 nm of aluminum is deposited as a cathode in a vapor deposition apparatus. Provided. A light emitting element was manufactured by extending aluminum lead wires from the anode and the cathode, respectively. The element was put in a glove box substituted with nitrogen gas, and sealed with a glass sealing container using an ultraviolet curable adhesive (manufactured by Chiba Nagase, XNR5493) to produce an organic EL element.

  When this organic EL element was energized, almost white light was obtained, and it was found that it could be used as a lighting device. It was also found that the organic EL device material in the present invention can be fabricated by coating.

Example 3
<Production of full-color display device>
(Production of blue light emitting element)
The organic EL element-15 of Example 1 was used as a blue light emitting element.

(Production of green light emitting element)
The organic EL element-13 of Example 1 was used as a green light emitting element.

(Production of red light emitting element)
Organic EL element-14 of Example 1 was used as a red light emitting element.

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

  It was found that by driving the full-color display device, a clear full-color moving image display with high emission luminance, high durability, and clearness can be obtained.

Example 4
<< Preparation of white light emitting element and white lighting device >>
The electrode of the transparent electrode substrate of Example 1 was patterned to 20 mm × 20 mm, and α-NPD was formed as a hole injection / transport layer with a thickness of 25 nm thereon as in Example 1, and further A-74 The heated boat containing the present invention, the boat containing the present compound 13 and the boat containing the present compound 16 are energized independently, respectively, and A-74 which is a luminescent host and the present compounds 13 and 16 which are luminescent dopants. The vapor deposition rate was adjusted to 100: 6: 1, vapor deposition was performed to a thickness of 30 nm, and a light emitting layer was provided.

Next, a hole blocking layer was provided by depositing BCP to a thickness of 10 nm. Furthermore, Alq ₃ was deposited at 40 nm to provide an electron transport layer.

  Next, as in Example 1, a square perforated mask having the same shape as the transparent electrode made of stainless steel was placed on the electron injection layer, and 0.5 nm of lithium fluoride was deposited as a cathode buffer layer and 150 nm of aluminum was deposited as a cathode. A film was formed.

  This element was provided with a sealing can having the same method and the same structure as in Example 1 to produce a flat lamp. 5 and 6 are schematic views of a flat lamp. FIG. 5 is a schematic view, and FIG. 6 is a cross-sectional view. When this flat lamp was energized, almost white light was obtained, and it was found that it could be used as a lighting device.

It is the schematic diagram which showed an example of the display apparatus comprised from an organic EL element. 4 is a schematic diagram of a display unit A. FIG. It is an equivalent circuit diagram of the drive circuit which comprises a pixel. It is a schematic diagram of the display apparatus by a passive matrix system. It is the schematic of an illuminating device. It is sectional drawing of an illuminating device.

Explanation of symbols

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

Claims (14)

A metal complex represented by the following general formula (1), wherein the tridentate ligand P ₁ or P ₂ has a substituent having 2 or more carbon atoms that suppress bidentate coordination: Electroluminescent element material.

(In the formula, M is a central metal. Tridentate ligands P ₁ and P ₂ are ligands bonded to the central metal M with three bonds, and P ₁ is represented by the following general formula (2). expressed.)

(In the formula, ring A, ring B and ring C are aromatic hydrocarbon rings or aromatic heterocyclic rings, and X, Y and Z constitute ring A, ring B and ring C, respectively, and are bonded to the central metal. At least one of which is a carbon atom, ring A-ring B and ring B-ring C are connected by L ₁ and L ₂ which are divalent linking groups. ₁ , R ₂ and R ₃ are substituents which may be further bonded to each other to form a ring, and n1, n2 and n3 are 0 or an integer of 1 or more. The material for an organic electroluminescence device according to claim 1, wherein the tridentate ligand P ₁ or P ₂ has a substituent having a van der Waals volume of 45 ³ or more. The material for an organic electroluminescent element according to claim 1, wherein the tridentate ligand P ₂ is represented by the general formula (2). In Formula (2) The organic electroluminescent device according to claim 1, wherein at least one of the substituents R ₂ of the B ring is van der Waals volume of 45 Å ³ or more Materials. The material for an organic electroluminescence device according to claim 1, wherein the tridentate ligand P ₂ is represented by the following general formula (3).

(In the formula, ring A, ring B and ring C are aromatic hydrocarbon rings or aromatic heterocyclic rings, and X, Y and Z constitute ring A, ring B and ring C, respectively, and are bonded to the central metal. At least one is a carbon atom, ring A-ring B, ring B-ring C are directly bonded, R ₁ , R ₂ , R ₃ are substituents And may be bonded to each other to form a ring, and n1, n2, and n3 are 0 or an integer of 1 or more.) In Formula (3), material for an organic electroluminescence device according to claim 5, wherein at least one of the substituents R ₂ of the B ring is van der Waals volume of 45 Å ³ or more. The material for an organic electroluminescence device according to any one of claims 1 to 6, wherein the metal complex represented by the general formula (1) is a part of a main chain or a side chain of a polymer. . The material for an organic electroluminescent element according to any one of claims 1 to 7, wherein the central metal M is selected from Ir, Rh, and Os. An organic electroluminescent element comprising the organic electroluminescent element material according to any one of claims 1 to 8 in any one of constituent layers. The organic electroluminescent element according to claim 9, wherein one of the constituent layers is a light emitting layer. The organic electroluminescent element according to claim 9 or 10, wherein a carbazole derivative is contained in at least one of the constituent layers. The organic electroluminescent element according to claim 9 or 10, wherein a compound represented by the following general formula (A) is contained in at least one of the constituent layers.

(Wherein Z ₁ represents an atomic group forming an aromatic heterocyclic ring, Z ₂ represents an atomic group forming an aromatic heterocyclic ring or an aromatic hydrocarbon ring, and Z ₃ represents a divalent linking group or .R ₁₀₁ representing the bond represents a hydrogen atom or a substituent.) A display device comprising the organic electroluminescence element according to claim 9. It has an organic electroluminescent element of any one of Claims 9-12, The illuminating device characterized by the above-mentioned.

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