JP5056016B2 - Organic electroluminescence element, display device and lighting device - Google Patents

Description

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

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

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

  On the other hand, an organic EL element has a structure in which a light emitting layer containing a compound that emits light is sandwiched between a cathode and an anode. By injecting electrons and holes into the light emitting layer and recombining them, excitons (exciton) are obtained. And emits light using 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. Since it is a light-emitting type, it has a wide viewing angle, high visibility, and since it is a thin-film type complete solid-state device, it has attracted attention from the viewpoints of space saving and portability.

  For the development of organic EL elements for practical use in the future, organic EL elements that emit light efficiently and with high brightness with lower power consumption are desired. For example, stilbene derivatives, distyrylarylene derivatives, or tris A technique for doping a styrylarylene derivative with a small amount of a phosphor to improve emission luminance and extend the lifetime of the device (see, for example, Patent Document 1), and 8-hydroxyquinoline aluminum complex as a host compound. A device having an organic light-emitting layer doped with a trace amount of phosphor (for example, see Patent Document 2), a device having an organic light-emitting layer doped with a quinacridone dye as a host compound using 8-hydroxyquinoline aluminum complex (for example, , See Patent Document 3).

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

  However, since Princeton University has reported on organic EL devices that use phosphorescence emission from excited triplets (see, for example, Non-Patent Document 1), research on materials that exhibit phosphorescence at room temperature has become active. (For example, see Non-Patent Document 2 and Patent Document 4.)

  When excited triplets are used, the upper limit of internal quantum efficiency is 100%, so in principle the luminous efficiency is four times that of excited singlets, and the performance is almost the same as that of cold cathode tubes. It can be applied to and attracts attention.

  For example, many compounds have been studied mainly for heavy metal complexes such as iridium complexes (see, for example, Non-Patent Document 3), and studies using tris (2-phenylpyridine) iridium as a dopant have been conducted. (For example, refer nonpatent literature 2.).

In addition, L ₂ Ir (acac), for example, (ppy) ₂ Ir (acac) (see, for example, Non-Patent Document 4) as a dopant, and tris (2- (p-tolyl) pyridine) iridium (as a dopant) Studies using Ir (ptpy) ₃ ), tris (benzo [h] quinoline) iridium (Ir (bzq) ₃ ), Ir (bzq) ₂ ClP (Bu) _3, etc. (for example, see Non-Patent Document 5). Has been done.

  Furthermore, in order to obtain high luminous efficiency, there is an example in which a hole transporting compound is used as a host of a phosphorescent compound (see, for example, Non-Patent Document 6), and various electron transporting materials are used as phosphorescent compounds. As these hosts, they are doped with a novel iridium complex (for example, see Non-Patent Document 4). Furthermore, high luminous efficiency is obtained by introducing a hole blocking layer (see, for example, Non-Patent Document 5).

  Recently, by doping the acceptor in the hole transport layer and the donor in the electron transport layer, the conductivity of the organic layer can be increased by increasing the carrier concentration in the hole transport layer and the electron transport layer in the thermal equilibrium state. An improved method has been proposed (see, for example, Patent Documents 5 and 6).

  Organic electroluminescence devices consisting of an electron transport layer doped with a donor and a hole blocking layer for efficiently confining holes, or an organic layer consisting of an electron transport layer doped with an acceptor and an electron blocking layer for efficiently confining electrons. An electroluminescence element has been proposed, and an organic electroluminescence element having a structure with excellent electro-optical properties and higher luminous efficiency has been obtained (see, for example, Patent Document 7).

  By the way, high-efficiency devices generally achieve high efficiency by laminating materials with different performance such as hole transport performance, electron transport performance, and light emission performance, and separating the functions in each layer. ing. On the other hand, by laminating an organic layer, a carrier injection barrier is generated at the organic-organic layer interface, and the driving voltage is likely to increase, and carriers are accumulated at the interface due to this injection barrier, leading to deterioration of the lifetime. There are problems such as being easy to be done. Furthermore, the film (layer) has poor adhesion at the interface between layers containing different materials, causing problems such as film peeling or crystallization of the material at the interface due to impurities. There are points, and these are major factors for deterioration of the lifetime of the device.

As a technique for improving these problems, a technique has been disclosed in which a progressive layer of a mixed light emitting layer of a hole transport material, an electron transport material and an electron injection material is provided to extend the life by eliminating the barrier between layers (for example, (See Patent Document 8)
However, in the above technique, since the region where the dopant is present is widened, the exciton confinement effect is small, and when the dopant has carrier transportability, the carrier confinement effect is also small, so that the efficiency is likely to decrease. is there.

  There is a technique for providing a mixed organic layer including a component that transports holes, a component that transports electrons, and a component that separates holes between the cathode and the anode (see, for example, Patent Document 9). Since a component that transports holes and a component that sequesters holes are mixed, hole blocking tends to be insufficient, and the existence region of the dopant is widened. In addition, there is a problem that it is necessary to deposit a plurality of kinds of materials at the same time, and manufacturing adjustment is quite difficult.

Further, between the cathode and the anode, a hole transporting mixed layer composed of a hole injection material and a hole transporting material, a bipolar mixed layer composed of a hole transporting material and an electron transporting material, or an electron transporting material and Although a technique (for example, refer to Patent Document 10) having an electron transporting mixed layer made of an electron injection material is disclosed, all of them are not sufficient in the effect of relaxing the energy barrier generated at the interface of the laminated structure, and are manufactured. The above difficulty is extremely high.
Japanese Patent No. 3093796 Japanese Unexamined Patent Publication No. 63-264692 JP-A-3-255190 US Pat. No. 6,097,147 Japanese Patent Laid-Open No. 4-297076 Japanese Patent Laid-Open No. 2001-244079 JP 2000-196140 A JP 2004-253315 A JP 2004-273197 A JP 2002-313583 A M.M. A. Baldo et al. , Nature, 395, 151-154 (1998) M.M. A. Baldo et al. , Nature, 403, 17, 750-753 (2000) S. Lamansky et al. , J .; Am. Chem. Soc. , 123, 4304 (2001) M.M. E. Thompson et al. , The 10th International Works on Organic and Organic Electroluminescence (EL'00, Hamamatsu) Moon-Jae Youn. 0 g, Tetsuo Tsutsui et al. , The 10th International Works on Organic and Organic Electroluminescence (EL'00, Hamamatsu) Ikai et al. , The 10th International Works on Organic and Organic Electroluminescence (EL'00, Hamamatsu)

  An object of the present invention is to provide an organic EL element, an illumination device, and a display device having a low voltage due to low resistance of an organic layer and a structure having excellent electro-optical characteristics with high luminous efficiency. An organic EL element, a lighting device, and a display device having a long light emission lifetime are provided.

One embodiment for accomplishing the present invention, the above object, between an anode and a cathode, has a single layer A containing at least one common host material to the single more A, said From the side close to the anode, a hole transport region containing at least one kind of hole transport material, a light emitting region containing at least one kind of light emitting dopant, and an undoped region composed only of the common host material are provided. The hole transport region and the light emitting region do not have a region overlapping each other, and the entire region of the single layer A contains 0.1% by mass or more of the common host material. The organic electroluminescence device is characterized in that the content of the material is approximately constant in each region, and at least one of the light-emitting dopants is a phosphorescent compound.

It is the schematic diagram which showed an example of the display apparatus comprised from an organic EL element. It is a schematic diagram of a display part. It is a schematic diagram of a pixel. It is a schematic diagram of a passive matrix type full-color display device. It is the schematic of an illuminating device. It is sectional drawing of an illuminating device. It is a schematic diagram which shows an example of the structural example of the single layer A of an element. It is a schematic diagram which shows an example of the vapor deposition apparatus used for single layer A formation of an element. It is a schematic diagram which shows an example of the organic EL element which has the single layer A which has a some light emission area | region and a some undoped area | region.

  The above object of the present invention has been achieved by the following constitutions 1 to 48.

  (1) having a single layer A containing at least one common host material between the anode and the cathode, wherein the single layer A contains at least one kind of hole transport material; A light-emitting region containing at least one kind of light-emitting dopant, the hole transport region and the light-emitting region do not have a region overlapping each other, and the common host material is reduced to 0 in all regions of the single layer A. 1. An organic electroluminescence device comprising 1% by mass or more, wherein the content of the common host material is approximately constant in each region.

  (2) The organic electroluminescent element, wherein a hole transport region and a light emitting region are provided from the side of the single layer A close to the anode.

  (3) The organic electroluminescence element, wherein an electron transport region and an undoped region are provided from the side of the single layer A close to the cathode.

  (4) The organic electroluminescence device, wherein a hole injection region, a hole transport region, and a light emitting region are provided from the side of the single layer A close to the anode.

  (5) The organic electroluminescence element, wherein an electron injection region and an undoped region are provided from the side of the single layer A close to the cathode.

  (6) A hole injection layer is provided between the anode and the single layer A, and the hole injection layer is different from the hole transport material included in the hole transport region of the single layer A. The organic electroluminescence device comprising the transport material A.

  (7) An electron injection layer is provided between the cathode and the single layer A, and the electron injection layer includes a material A different from the electron transport material included in the electron transport region of the single layer A. The organic electroluminescence device as described above.

  (8) The organic electroluminescence device, wherein at least one of the light-emitting dopants is a phosphorescent compound.

  (9) The organic electroluminescence device, wherein the hole transport region contains 0.1% by mass to 10% by mass of a common host material.

  (10) The organic electroluminescent element, wherein the light emitting region contains 51 mass% to 99.9 mass% of a common host material.

  (11) The organic electroluminescence element, wherein the electron transport region contains 0.1% by mass to 10% by mass of a common host material.

  (12) The organic electroluminescence element, wherein the electron injection region contains 51 mass% to 99.9 mass% of a common host material.

  (13) The organic electroluminescence device, wherein the hole injection region contains 0.1 mass% to 99,9 mass% of a common host material.

  (14) The organic electroluminescence device, wherein the lowest excited triplet energy level T1 of the common host material and the lowest excited triplet energy level T2 of the luminescent dopant satisfy the following relational expression.

T1 ≧ T2
(15) The organic electroluminescence device, wherein at least one of the common host materials is a compound represented by the following general formula (1).

[Wherein, Z ₁ represents an aromatic heterocyclic ring which may have a substituent, Z ₂ represents an aromatic heterocyclic ring or an aromatic hydrocarbon ring which may each have a substituent, Z ₃ represents a divalent linking group or a simple bond. R ₁₀₁ represents a hydrogen atom or a substituent. ]
(16) The organic electroluminescence device, wherein Z _{1 of the} compound represented by the general formula (1) is a 6-membered ring.

(17) The organic electroluminescence device, wherein Z _{2 of the} compound represented by the general formula (1) is a 6-membered ring.

(18) The organic electroluminescence device, wherein Z _{3 of the} compound represented by the general formula (1) is a bond.

  (19) The organic electroluminescence device, wherein the compound represented by the general formula (1) has a molecular weight of 450 or more.

  (20) The organic electroluminescence device, wherein the compound represented by the general formula (1) is represented by the following general formula (1-1).

[Wherein, R _{501 to} R ₅₀₇ each independently represents a hydrogen atom or a substituent, and the substituents may be the same or different. ]
(21) The organic electroluminescence device, wherein the compound represented by the general formula (1) is represented by the following general formula (1-2).

[Wherein, R _{511 to} R ₅₁₇ each independently represents a hydrogen atom or a substituent, and the substituents may be the same or different. ]
(22) The organic electroluminescence device, wherein the compound represented by the general formula (1) is represented by the following general formula (1-3).

[Wherein, R _{521 to} R ₅₂₇ each independently represents a hydrogen atom or a substituent, and the substituents may be the same or different. ]
(23) The organic electroluminescence device, wherein the compound represented by the general formula (1) is represented by the following general formula (1-4).

[Wherein, R _{531 to} R ₅₃₇ each independently represents a hydrogen atom or a substituent, and the substituents may be the same or different. ]
(24) The organic electroluminescence device, wherein the compound represented by the general formula (1) is represented by the following general formula (1-5).

[Wherein, R _{541 to} R ₅₄₈ each independently represents a hydrogen atom or a substituent, and the substituents may be the same or different. ]
(25) The organic electroluminescence device, wherein the compound represented by the general formula (1) is represented by the following general formula (1-6).

[Wherein, R _{551 to} R ₅₅₈ each independently represent a hydrogen atom or a substituent, and the substituents may be the same or different. ]
(26) The organic electroluminescence device, wherein the compound represented by the general formula (1) is represented by the following general formula (1-7).

[Wherein, R _{561 to} R ₅₆₇ each independently represents a hydrogen atom or a substituent, and the substituents may be the same or different. ]
(27) The organic electroluminescence device, wherein the compound represented by the general formula (1) is represented by the following general formula (1-8).

[Wherein, R _{571 to} R ₅₇₇ each independently represents a hydrogen atom or a substituent, and the substituents may be the same or different. ]
(28) The organic electroluminescence device, wherein the compound represented by the general formula (1) is represented by the following general formula (1-9).

[Wherein, R _{581 to} R ₅₈₈ each represent a hydrogen atom or a substituent, and the substituents may be the same or different. ]
(29) The organic electroluminescence device, wherein the compound represented by the general formula (1) is represented by the following general formula (1-10).

[Wherein, R _{591 to} R ₅₉₈ each represent a hydrogen atom or a substituent, and the substituents may be the same or different. ]
(30) The organic compound, wherein the compound represented by the general formula (1) has at least one group represented by any one of the following general formulas (2-1) to (2-10) Electroluminescence element.

_{Wherein, R 502 ~R 507, R 512} ~R 517, R 522 ~R 527, R 532 ~R 537, R 542 ~R 548, R 552 ~R 558, R 562 ~R 567, R 572 ~R ₅₇₇ , R _{582 to} R ₅₈₈ and R _{592 to} R ₅₉₈ each independently represent a hydrogen atom or a substituent, and the substituents may be the same or different. ]
(31) The organic electroluminescence device, wherein the compound represented by the general formula (1) is represented by the following general formula (3).

[Wherein, R _{601 to} R ₆₀₆ each independently represents a hydrogen atom or a substituent, and at least one of R _{601 to} R ₆₀₆ is represented by Formulas (2-1) to (2-10). Represents at least one group selected from the following groups. ]
(32) The organic electroluminescence device, wherein the compound represented by the general formula (1) is represented by the following general formula (4).

[Wherein, R _{611 to} R ₆₂₀ each independently represents a hydrogen atom or a substituent, and at least one of R _{611 to} R ₆₂₀ is represented by the general formulas (2-1) to (2-10). Represents at least one group selected from the following groups. ]
(33) The organic electroluminescence device, wherein the compound represented by the general formula (1) is represented by the following general formula (5).

[Wherein, R _{621 to} R ₆₂₃ each independently represents a hydrogen atom or a substituent, and at least one of R _{621 to} R ₆₂₃ is represented by the general formulas (2-1) to (2-10). Represents at least one group selected from the following groups. ]
(34) The organic electroluminescence device, wherein the compound represented by the general formula (1) is represented by the following general formula (6).

[Wherein, R _{631 to} R ₆₄₅ each independently represent a hydrogen atom or a substituent, and at least one of R _{631 to} R ₆₄₅ is represented by Formulas (2-1) to (2-10). Represents at least one group selected from the following groups. ]
(35) The organic electroluminescence device, wherein the compound represented by the general formula (1) is represented by the following general formula (7).

[Wherein, R _{651 to} R ₆₅₆ each independently represents a hydrogen atom or a substituent, and at least one of R _{651 to} R ₆₅₆ is represented by the general formulas (2-1) to (2-10). Represents at least one group selected from the following groups. na represents an integer of 0 to 5, and nb represents an integer of 1 to 6, but the sum of na and nb is 6. ]
(36) The organic electroluminescence device, wherein the compound represented by the general formula (1) is represented by the following general formula (8).

[Wherein R _{661 to} R ₆₇₂ each independently represents a hydrogen atom or a substituent, and at least one of R _{661 to} R ₆₇₂ is represented by the general formulas (2-1) to (2-10). Represents at least one group selected from the following groups. ]
(37) The organic electroluminescence device, wherein the compound represented by the general formula (1) is represented by the following general formula (9).

[Wherein, R _{681 to} R ₆₈₈ each independently represents a hydrogen atom or a substituent, and at least one of R _{681 to} R ₆₈₈ is represented by the general formulas (2-1) to (2-10). Represents at least one group selected from the following groups. ]
(38) The organic electroluminescence device, wherein the compound represented by the general formula (1) is represented by the following general formula (10).

[Wherein, R _{691 to} R ₇₀₀ each independently represents a hydrogen atom or a substituent, and L ₁ represents a divalent linking group. At least one of R _{691 to} R ₇₀₀ represents at least one group selected from the groups represented by the general formulas (2-1) to (2-10). ]
(39) The organic electroluminescence device, wherein the compound represented by the general formula (1) is represented by the following general formula (11).

[Wherein, R ₁ and R ₂ each independently represents a hydrogen atom or a substituent. n and m each represent an integer of 1 to 2, and k and l each represent an integer of 3 to 4. However, n + k = 5 and l + m = 5. ]
(40) The organic electroluminescence device, wherein the compound represented by the general formula (1) is represented by the following general formula (12).

[Wherein, R ₁ and R ₂ each independently represents a hydrogen atom or a substituent. n and m each represent an integer of 1 to 2, and k and l each represent an integer of 3 to 4. However, n + k = 5 and l + m = 5. ]
(41) The organic electroluminescence device, wherein the compound represented by the general formula (1) is represented by the following general formula (13).

[Wherein, R ₁ and R ₂ each independently represents a hydrogen atom or a substituent. n and m each represent an integer of 1 to 2, and k and l each represent an integer of 3 to 4. However, n + k = 5 and l + m = 5. ]
(42) The organic electroluminescence device, wherein the compound represented by the general formula (1) is represented by the following general formula (14).

[Wherein, R ₁ and R ₂ each independently represents a hydrogen atom or a substituent. n and m each represent an integer of 1 to 2, and k and l each represent an integer of 3 to 4. However, n + k = 5 and l + m = 5. ]
(43) The organic electroluminescence device, wherein the compound represented by the general formula (1) is represented by the following general formula (15).

[Wherein, R ₁ and R ₂ each independently represents a hydrogen atom or a substituent. n and m each represent an integer of 1 to 2, and k and l each represent an integer of 3 to 4. However, n + k = 5 and l + m = 5. Z ₁ , Z ₂ , Z ₃ and Z ₄ each represents a 6-membered aromatic heterocyclic ring containing at least one nitrogen atom. ]
(44) The organic electroluminescence device, wherein the compound represented by the general formula (1) is represented by the following general formula (16).

[Wherein, o and p each represent an integer of 1 to 3, and Ar ₁ and Ar ₂ each represent an arylene group or a divalent aromatic heterocyclic group. Z ₁ and Z ₂ each represent a 6-membered aromatic heterocyclic ring containing at least one nitrogen atom, and L represents a divalent linking group. ]
(45) The organic electroluminescence device, wherein the compound represented by the general formula (1) is represented by the following general formula (17).

[Wherein, o and p each represent an integer of 1 to 3, and Ar ₁ and Ar ₂ each represent a divalent arylene group or a divalent aromatic heterocyclic group. Z ₁ , Z ₂ , Z ₃ and Z ₄ each represents a 6-membered aromatic heterocyclic ring containing at least one nitrogen atom, and L represents a divalent linking group. ]
(46) The organic electroluminescent device characterized by emitting white light.

  (47) A display device comprising the organic electroluminescence element.

  (48) An illumination device comprising the organic electroluminescence element.

  In the organic EL device of the present invention, the configuration defined in any one of (1) to (48) provides an organic EL device having a low driving voltage and a high external extraction quantum efficiency, Using an organic EL element, a high-luminance lighting device and display device can be provided.

  As a result of various studies on the above-mentioned problems, the present inventors have improved the adhesion between the regions by containing at least one common host material in all regions. It has been found that the injection barrier of electrons and the like is relaxed and the drive voltage can be lowered (specifically, lm / W improvement).

  In the present invention, the hole transport material used for forming the hole transport region of the organic EL element and the light emitting dopant material used for forming the light emitting region are not mixed and used, but contain a common host material. By providing each independent region (hole transport region, light emitting region, etc.) in the single layer A, it can be driven at a low voltage without impairing the confinement effect of carriers and excitons, and has high luminous efficiency. The present invention has succeeded in obtaining an organic EL device having a long emission lifetime.

  The present inventors consider the reason why the above effect is obtained as follows.

  (1) Relaxation of the injection barrier for holes, electrons, etc. can prevent the accumulation of carriers at the interface as well as the driving voltage drop, and the improvement in film adhesion prevents the intrusion of impurities into the interface. This is effective in preventing crystallization at the interface between the organic layer and the organic layer, resulting in a longer lifetime of the device.

  (2) The hole transport material has a function of transporting holes and blocking electrons flowing from the cathode side, but the radical anion state is unstable in nature. By trapping the electrons from which the common host material A has leaked and preventing radical anionization of the hole transport material, an element having a longer lifetime can be obtained.

  (3) From the viewpoint of manufacturing an organic EL element by using a common host material for all regions, there is an effect that the element manufacturing is simplified.

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

<< Single layer A >>
The single layer A according to the organic EL element of the present invention will be described.

  The single layer A according to the present invention is provided between the cathode and the anode of the organic EL device of the present invention, and the single layer A includes at least one hole transport region containing at least one kind of hole transport material. A light-emitting region containing various kinds of light-emitting dopants and at least one common host material is contained in an amount of 0.1% by mass or more in any region (also referred to as a layer) of the entire region of the single layer A. Is a feature.

  In addition, the single layer A according to the present invention is a non-doped region (the function of the non-doped region is not necessarily limited to hole blocking), which is related to the blocking of holes related to the light emission of the organic EL element and the transport of electrons. Will be described in the structure of the element.), An electron transport region and the like can be used alone or in combination.

As a preferable aspect of the single layer A according to the organic EL element of the present invention, for example,
(A) From the side close to the anode of the single layer A, a hole transport region and a light emitting region are provided,
(B) From the side close to the cathode of the single layer A, an electron transport region and an undoped region are provided.
(C) A hole injection region, a hole transport region, and a light emitting region are provided from the side close to the anode of the single layer A,
(D) From the side close to the cathode of the single layer A, an electron injection region and an undoped region are provided.
Etc., and
(E) a hole injection layer between the anode and the single layer A, the hole injection layer being different from the hole transport material contained in the hole transport region of the single layer A Including transport material A,
(F) An electron injection layer is provided between the cathode and the single layer A, and the electron injection layer includes an electron injection material A different from the electron injection material included in the electron injection region of the single layer A. ,
Etc. are mentioned as a preferred embodiment.

  Although the single layer A according to the present invention is provided between the anode and the cathode, the single layer A may be provided directly on each electrode of the anode and / or the cathode. Although another layer may be provided between the anode and / or the above, in the present invention, a hole injection layer is provided between the anode and the single layer A. In the meantime, it is preferable to provide an electron injection layer.

  Hole transport region, light emitting region, electron transport region, hole blocking region, electron injection region, and other regions forming the single layer A, hole injection layer provided between the anode and the single layer A, anode and cathode The electron injection layer and the like provided between and will be described in detail in the configuration of the organic EL element described later.

  In the single layer A according to the present invention, the common host material is present in an amount of 0.1% by mass or more in any region, and the content of the common host material is approximately constant in each region. Here, means for measuring the content of the common host material in each region will be described below.

(Method for measuring content of common host material in each region of single layer A)
The content ratio of the common host material in each region in the single layer A can be calculated by applying the following analysis method.

The content analysis of the common host material in each region of the single layer A according to the present invention is the 65th Japan Society of Applied Physics Academic Lecture, Proceedings of Lecture, 1183 pages, 3p-ZR-20, Toray Research Center, Inc. Shibamori As described in Takahiro, Seki Hirofumi, Matsunobu Tsuyoshi, and Nakagawa Yoshitsugu, analysis is performed by applying a technique that combines the “precision oblique cutting method” and time-of-flight secondary ion mass spectrometry (TOF-SIMS). Can be calculated.
Note that the content of the common host material being substantially constant in each region means that there is no concentration gradient.

  Common host materials used in the present invention typically have basic skeletons such as carbazole derivatives, triarylamine derivatives, aromatic borane derivatives, nitrogen-containing heterocyclic compounds, thiophene derivatives, furan derivatives, oligoarylene compounds, etc. Or a carboline derivative or a diazacarbazole derivative (herein, a diazacarbazole derivative represents one in which at least one carbon atom of the hydrocarbon ring constituting the carboline ring of the carboline derivative is substituted with a nitrogen atom). ) And the like.

  Of these, carboline derivatives and diazacarbazole derivatives are preferable, and compounds represented by the above general formula (1) are particularly preferably used.

  As the common host material according to the present invention, the compound represented by the general formula (1) is particularly preferably used.

<< Compound Represented by Formula (1) >>
The compound represented by the general formula (1) according to the present invention will be described.

  As a result of intensive studies, the present inventors have prepared the compound represented by the general formula (1) in a light emitting layer or an adjacent layer of the light emitting layer, and using a phosphorescent compound described later for the light emitting layer. It has been found that the organic EL device has high luminous efficiency and can have a long lifetime.

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

In the general formula (1), examples of the aromatic heterocycle represented by 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, Diazole 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, carboline ring And a ring in which the carbon atom of the hydrocarbon ring is further substituted with a nitrogen atom. Furthermore, the aromatic heterocyclic ring may have a substituent represented by R ₁₀₁ described later.

In the general formula (1), examples of the aromatic hydrocarbon ring represented by Z ₂ 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. Furthermore, the aromatic hydrocarbon ring may have a substituent represented by R ₁₀₁ described later.

In the general formula (1), examples of the substituent represented by R ₁₀₁ include an alkyl group (eg, methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, octyl group, dodecyl group). 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.) Etc.), aryl groups (eg phenyl group, naphthyl group etc.), aromatic heterocyclic groups (eg 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, imidazolidyl 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.), cyclo An alkoxyl group (eg, cyclopentyloxy group, cyclohexyloxy group, etc.), an aryloxy group (eg, phenoxy group, naphthyloxy group, etc.), an 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 meso Ruoxycarbonyl group, 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, cyclyl group) Hexylcarbonyl 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, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide group (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonyl) Amino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthy Carbonylamino group, etc.), carbamoyl group (eg, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylamino) Carbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), ureido group (for example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido group) , Dodecylureido group, phenylureido group naphthylureido group, 2-pyridylaminoureido group, etc.), sulfinyl group (for example, methylsulfinyl group, ethyl) Rufinyl group, butylsulfinyl 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 (phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group etc.), amino group (for example, amino group, ethyl group) Amino group, dimethylamino group, butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, naphthylamino group, 2-pyridy Amino groups, etc.), halogen atoms (eg, fluorine atoms, chlorine atoms, bromine atoms, etc.), fluorinated hydrocarbon groups (eg, fluoromethyl groups, trifluoromethyl groups, pentafluoroethyl groups, pentafluorophenyl groups, etc.), And cyano group, nitro group, hydroxy 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.

  As the divalent linking group, in addition to hydrocarbon groups such as alkylene, alkenylene, alkynylene, and arylene, those containing a hetero atom may be used, and a thiophene-2,5-diyl group, pyrazine-2, It may be a divalent linking group derived from a compound having an aromatic heterocyclic ring (also called a heteroaromatic compound) such as a 3-diyl group, or may be a chalcogen atom such as oxygen or sulfur. . Further, it may be a group such as an alkylimino group, a dialkylsilanediyl group, or a diarylgermandiyl group that joins and connects heteroatoms.

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

In the present invention, Z _{1 in the} general formula (1) is preferably a 6-membered ring. Thereby, luminous efficiency can be made higher. Furthermore, the lifetime can be further increased.

In the present invention, it is preferable that the Z ₂ in the general formula (1) is a 6-membered ring. Thereby, luminous efficiency can be made higher. Furthermore, the lifetime can be further increased.

Furthermore, it is preferable that Z ₁ and Z _{2 in} the general formula (1) are both 6-membered rings because the luminous efficiency can be further increased. Furthermore, it is preferable because the lifetime can be further increased.

  Preferred among the compounds represented by the general formula (1) are compounds represented by the general formulas (1-1) to (1-13).

In the general formula (1-1), R _{501 to} R ₅₀₇ each independently represent a hydrogen atom or a substituent, and the substituents may be the same or different.

  By using the compound represented by the general formula (1-1), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (1-2), R _{511 to} R ₅₁₇ each independently represent a hydrogen atom or a substituent, and the substituents may be the same or different.

  By using the compound represented by the general formula (1-2), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (1-3), R _{521 to} R ₅₂₇ each independently represent a hydrogen atom or a substituent, and the substituents may be the same or different.

  By using the compound represented by the general formula (1-3), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (1-4), R _{531 to} R ₅₃₇ each independently represent a hydrogen atom or a substituent, and the substituents may be the same or different.

  By using the compound represented by the general formula (1-4), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (1-5), R _{541 to} R ₅₄₈ each independently represent a hydrogen atom or a substituent, and the substituents may be the same or different.

  By using the compound represented by the general formula (1-5), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (1-6), R _{551 to} R ₅₅₈ each independently represent a hydrogen atom or a substituent, and the substituents may be the same or different.

  By using the compound represented by the general formula (1-6), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (1-7), R _{561 to} R ₅₆₇ each independently represent a hydrogen atom or a substituent, and the substituents may be the same or different.

  By using the compound represented by the general formula (1-7), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (1-8), R _{571 to} R ₅₇₇ each independently represent a hydrogen atom or a substituent, and the substituents may be the same or different.

  By using the compound represented by the general formula (1-8), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (1-9), R _{581 to} R ₅₈₈ each represent a hydrogen atom or a substituent, and the substituents may be the same or different.

  By using the compound represented by the said General formula (1-9), it can be set as an organic electroluminescent element with higher luminous efficiency. Furthermore, it can be set as a longer life organic EL element.

In the general formula (1-10), R _{591 to} R ₅₉₈ each represent a hydrogen atom or a substituent, and the substituents may be the same or different.

  By using the compound represented by the general formula (1-10), an organic EL device with higher luminous efficiency can be obtained. Furthermore, a long-life organic EL element can be obtained.

Moreover, what is preferable among the compounds represented by the general formula (1) is a compound having at least one group represented by any one of the general formulas (2-1) to (2-10). In particular, it is more preferable to have 2 to 4 groups represented by any one of the general formulas (2-1) to (2-10) in the molecule. In this case, the structure represented by the general formula (1) includes a case where the portion excluding R ₁₀₁ is replaced by the general formulas (2-1) to (2-10).

  At this time, the compounds represented by the general formulas (3) to (49) are particularly preferable for obtaining the effects of the present invention.

In the general formula (3), R _{601 to} R ₆₀₆ represent a hydrogen atom or a substituent, and at least one of R _{601 to} R ₆₀₆ is represented by the general formulas (2-1) to (2-10). The group represented by either is represented.

  By using the compound represented by the general formula (3), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (4), R _{611 to} R ₆₂₀ represent a hydrogen atom or a substituent, and at least one of R _{611 to} R ₆₂₀ is represented by the general formulas (2-1) to (2-10). The group represented by either is represented.

  By using the compound represented by the general formula (4), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (5), R _{621 to} R ₆₂₃ represent a hydrogen atom or a substituent, and at least one of R _{611 to} R ₆₂₀ is represented by the general formulas (2-1) to (2-10). The group represented by either is represented.

  By using the compound represented by the general formula (5), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (6), R _{631 to} R ₆₄₅ represent a hydrogen atom or a substituent, and at least one of R _{631 to} R ₆₄₅ is represented by the general formulas (2-1) to (2-10). The group represented by either is represented.

  By using the compound represented by the general formula (6), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (7), R _{651 to} R ₆₅₆ represent a hydrogen atom or a substituent, and at least one of R _{651 to} R ₆₅₆ is represented by the general formulas (2-1) to (2-10). The group represented by either is represented. na represents an integer of 0 to 5, and nb represents an integer of 1 to 6, but the sum of na and nb is 6.

  By using the compound represented by the general formula (7), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (8), R _{661 to} R _{672 each} represents a hydrogen atom or a substituent, and at least one of R _{661 to} R ₆₇₂ is represented by the general formulas (2-1) to (2-10). The group represented by either is represented.

  By using the compound represented by the general formula (8), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (9), R _{681 to} R ₆₈₈ represent a hydrogen atom or a substituent, and at least one of R _{681 to} R ₆₈₈ is represented by the general formulas (2-1) to (2-10). The group represented by either is represented.

  By using the compound represented by the general formula (9), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (10), R _{691 to} R ₇₀₀ represent a hydrogen atom or a substituent, and at least one of R _{691 to} R ₇₀₀ is represented by the general formulas (2-1) to (2-10). The group represented by either is represented.

In the general formula (10), the divalent linking group represented by L ₁ is an alkylene group (for example, ethylene group, trimethylene group, tetramethylene group, propylene group, ethylethylene group, pentamethylene group, hexamethylene). Group, 2,2,4-trimethylhexamethylene group, heptamethylene group, octamethylene group, nonamethylene group, decamethylene group, undecamethylene group, dodecamethylene group, cyclohexylene group (for example, 1,6-cyclohexanediyl group, etc.) ), Cyclopentylene group (eg, 1,5-cyclopentanediyl group, etc.), alkenylene group (eg, vinylene group, propenylene group, etc.), alkynylene group (eg, ethynylene group, 3-pentynylene group, etc.), In addition to hydrocarbon groups such as arylene groups, groups containing heteroatoms (eg, —O , -S- and the like, a divalent group containing a chalcogen atom, -N (R)-group, wherein R represents a hydrogen atom or an alkyl group, and the alkyl group in the general formula (1), And the same as the alkyl group represented by R ₁₀₁ .

  In each of the alkylene group, alkenylene group, alkynylene group, and arylene group, at least one of carbon atoms constituting the divalent linking group is a chalcogen atom (oxygen, sulfur, etc.) or -N (R). -It may be substituted with a group or the like.

Furthermore, as the divalent linking group represented by L ₁ , for example, a group having a divalent heterocyclic group is used. For example, an oxazolediyl group, a pyrimidinediyl group, a pyridazinediyl group, a pyrandiyl group, a pyrrolindiyl group. Group, imidazoline diyl group, imidazolidine diyl group, pyrazolidine diyl group, pyrazoline diyl group, piperidine diyl group, piperazine diyl group, morpholine diyl group, quinuclidine diyl group and the like, and thiophene-2,5- A divalent linking group derived from a compound having an aromatic heterocyclic ring (also referred to as a heteroaromatic compound) such as a diyl group or a pyrazine-2,3-diyl group may be used.

  Further, it may be a group that meets and links heteroatoms such as an alkylimino group, a dialkylsilanediyl group, or a diarylgermandiyl group.

  By using the compound represented by the general formula (10), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the compounds represented by the general formula (11) to the general formula (15), the substituents represented by R ₁ and R ₂ are the substituents represented by R ₁₀₁ in the general formula (1). At the same time as the group.

In the general formula (15), examples of the 6-membered aromatic heterocyclic ring each containing at least one nitrogen atom represented by Z ₁ , Z ₂ , Z ₃ , and Z ₄ include a pyridine ring and a pyridazine ring. , Pyrimidine ring, pyrazine ring and the like.

In the general formula (16), examples of the 6-membered aromatic heterocycle each containing at least one nitrogen atom represented by Z ₁ and Z ₂ include a pyridine ring, a pyridazine ring, a pyrimidine ring, and a pyrazine ring. Etc.

In the general formula (16), the arylene groups represented by Ar ₁ and Ar ₂ include o-phenylene group, m-phenylene group, p-phenylene group, naphthalenediyl group, anthracenediyl group, naphthacenediyl group, and pyrenediyl group. Group, naphthylnaphthalenediyl group, biphenyldiyl group (for example, 3,3′-biphenyldiyl group, 3,6-biphenyldiyl group, etc.), terphenyldiyl group, quaterphenyldiyl group, kinkphenyldiyl group, sexi Examples thereof include a phenyldiyl group, a septiphenyldiyl group, an octylphenyldiyl group, a nobiphenyldiyl group, and a deciphenyldiyl group. The arylene group may further have a substituent described later.

In the general formula (16), the divalent aromatic heterocyclic groups represented by Ar ₁ and Ar ₂ are furan ring, thiophene ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, triazine ring, benzo Imidazole ring, 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, And divalent groups derived from a ring in which the carbon atom of the hydrocarbon ring constituting the carboline ring is further substituted with a nitrogen atom. Furthermore, the aromatic heterocyclic group may have a substituent represented by R ₁₀₁ .

In the general formula (16), the divalent linking group represented by L has the same meaning as the divalent linking group represented by L ₁ in the general formula (10), but is preferably an alkylene group. , —O—, —S— and the like, are divalent groups containing a chalcogen atom, most preferably an alkylene group.

In the general formula (17), in Ar _1, Ar _2, the arylene group represented by each, in the general formula (16), is synonymous with the arylene group represented by each of Ar _1, Ar _2.

In the general formula (17), an aromatic heterocyclic group represented by each of Ar _1, Ar _2, in the general formula (16), the divalent aromatic heterocyclic ring represented by each of Ar _1, Ar ₂ Synonymous with group.

In the general formula (17), examples of the 6-membered aromatic heterocycle each containing at least one nitrogen atom represented by Z ₁ , Z ₂ , Z ₃ , and Z ₄ include a pyridine ring and a pyridazine ring. , Pyrimidine ring, pyrazine ring and the like.

In the general formula (17), the divalent linking group represented by L has the same meaning as the divalent linking group represented by L ₁ in the general formula (10), but preferably an alkylene group, It is a divalent group containing a chalcogen atom such as —O— or —S—, and most preferably an alkylene group.

  Although the specific example of a compound represented by General formula (1) based on this invention below is shown, this invention is not limited to these.

  The light emitting host 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). .

  As the light-emitting host, a compound having a hole transporting ability and an electron transporting ability and 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 Application Laid-Open Nos. 2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, 2002-8860 Gazette, 2002-334787 gazette, 2002-15871 gazette, 2002-334788 gazette, 2002-43056 gazette, 2002-334789 gazette, 2002-75645 gazette, 2002-338579 gazette. No. 2002-105445, No. 2002-343568, No. 2002-141173, No. 2002-352957, No. 2002-203683, No. 2002-363227, No. 2002-231453. No. 2003-3165, No. 2002-234888, No. 2003-27048, No. 2002-255934, No. 2002-286061, No. 2002-280183, No. 2002-299060. 2002-302516, 2002-305083, 2002-305084, 2002-308837, and the like.

<< Configuration of organic EL element >>
The layer configuration of the organic EL element of the present invention, the region configuration of the single layer A, etc. 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. In the following layer structure, the single layer A contains the common host material in an amount of 0.1% by mass or more per layer in any region. (I) Anode / single layer A (hole transport region, light emitting region, undoped region) / cathode (ii) Anode / single layer A (hole transport region, undoped region, light emitting region, undoped region, electron transport) Region) / cathode (iii) anode / single layer A (hole transport region, light emitting region, undoped region, electron transport region) / cathode (iv) anode / single layer A (hole transport region, light emitting region, undoped) Region, electron injection region) / cathode (v) anode / hole injection layer / single layer A (hole transport region, light emitting region, undoped region, electron transport region) / cathode (vi) anode / hole injection layer / Single layer A (hole transport region, light emitting region, undoped region, electron transport region) / electron injection layer / cathode In the layer configuration of the organic EL device of the present invention, the following configuration, specifically,
(1) A hole transport region and a light emitting region are provided from the side close to the anode of the single layer A.
(2) From the side close to the cathode of the single layer A, an electron transport region and an undoped region are provided.
(3) A hole injection region, a hole transport region, and a light emitting region are provided from the side close to the anode of the single layer A.
(4) From the side close to the cathode of the single layer A, an electron injection region and an undoped region are provided.
Is an example of a preferred layer configuration.

  Here, taking the above embodiment (a) as an example, the hole transport region and the light emitting region are provided from the side close to the anode of the single layer A, but adjacent to the hole transport region. The light emitting region may be provided, and an undoped region to be described later may be provided between the hole transport region and the light emitting region.

  The presence of such an undoped region is the same in the other preferred embodiments (b), (c), and (d).

<< Example of layer structure of single layer A >>
The structural example of the single layer A which concerns on this invention to an organic EL element is demonstrated using Fig.7 (a)-FIG.7 (f). In each figure, the vertical axis indicates the mass% of the material in each region, and the horizontal axis indicates the film thickness of the single layer A. 7A to 7F, 300 represents a single layer A.

  FIG. 7A shows an example of a configuration in which a hole transport region 302, a light emitting region 303, and then an undoped region 301 are provided from the anode side to the cathode side of the single layer A. The hole transport region 302 includes a hole transport material 302a and a common host material 301a, the light emitting region 303 includes a light emitting dopant 303a and a common host material 301a, and the undoped region 301 is substantially a common host. It is formed only from the material 301a.

  Here, “substantially” means that the content of the common host material 301a in the region is 99.9% by mass or more.

  FIG. 7B shows a configuration in which a hole transport region 302, an undoped region 301, a light emitting region 303, an undoped region 301, and then an electron transport region 304 are provided from the anode side to the cathode side of the single layer A. It is an example. The hole transport region 302, the undoped region 301, and the light emitting region 303 are the same as those in FIG. 7A, and the electron transport region 304 includes the electron transport material 304a and the common host material 301a.

  FIG. 7C shows an example of a configuration in which a hole transport region 302, an undoped region 301, a light emitting region 302, and an undoped region 301 are provided from the anode side to the cathode side of the single layer A. The configurations of the hole transport region 302, the undoped region 301, and the light emitting region 303 are the same as those in FIG.

  FIG. 7D shows a hole injection region 305, a hole transport region 302, an undoped region 301, a light emitting region 303, an undoped region 301, and then an electron injection region 306 from the anode side to the cathode side of the single layer A. This is an example of a configuration in which is provided. The hole transport region 302, the undoped region 301, and the light emitting region 303 are the same as the structure in FIG. 7A, and the hole injection region 305 includes a hole injection material 305 a and the electron injection region 306 includes Includes an electron injection material 306a.

  FIG. 7E shows a hole transport region 302, an undoped region 301, a blue light emitting region 307, an undoped region 301, a green light emitting region 308, an undoped region 301, a blue color from the anode side to the cathode side of the single layer A. This is an example of a configuration in which a light emitting region 309 and then an undoped region 301 are provided.

  Here, the hole transport region 302 and the undoped region 301 have the same structure as that shown in FIG. 7A. The blue light emitting region 307 has a blue light emitting dopant 307a, and the green light emitting region 308 has a green light emitting region 308. The green light emitting dopant 308a and the red light emitting region 309 contain the red light emitting dopant 309a.

  FIG. 7F shows a hole injection region 305, a hole transport region 302, an undoped region 301, a blue light emitting region 307, an undoped region 301, a green light emitting region 308, from the anode side to the cathode side of the single layer A. An example of a configuration in which an undoped region 301, a blue light emitting region 309, an undoped region 301, and then an electron injection region 306 are provided is shown.

  Here, each of the hole injection region 305, the hole transport region 302, the undoped region 301, the blue light emitting region 307, the green light emitting region 308, and the red light emitting region 309 is the same as the configuration in FIG. The blue light emitting region 307 contains a blue light emitting dopant 307a, the green light emitting region 308 contains a green light emitting dopant 308a, and the red light emitting region 309 contains a red light emitting dopant 309a. The electron injection region 306 is the same as that shown in FIG. 7D, and the electron injection region 306 contains an electron injection material 306a.

《Hole transport region》
The hole transport region includes a hole transport material having a function of transporting holes, and in a broad sense, a hole injection region and an electron blocking region are also included in the hole transport region. The hole transport region 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.

  Examples of the hole transport region according to the present invention include triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives. Conventionally known materials such as styryl anthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers may be used.

  As the hole transport material, those described above can be used, but it is preferable to use a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound.

  Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N, N ′, N′-tetraphenyl-4,4′-diaminophenyl; N, N′-diphenyl-N, N′— Bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (TPD); 2,2-bis (4-di-p-tolylaminophenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ′, N′-tetra-p-tolyl-4,4′-diaminobiphenyl; 1,1-bis (4-di-p-tolyl) Aminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-p-tolylaminophenyl) phenylmethane; N, N'-diphenyl-N, N ' − (4-methoxyphenyl) -4,4'-diaminobiphenyl; N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) quadriphenyl; N, N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenylamino- (2-diphenylvinyl) benzene; 3-methoxy-4′-N, N-diphenylaminostilbenzene; N-phenylcarbazole, and two more described in US Pat. No. 5,061,569 Having a condensed aromatic ring of, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-308 4,4 ', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (MTDATA) in which three triphenylamine units described in No. 88 are linked in a starburst type ) 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.

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

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

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

  Further, from the viewpoint of improving the light emission efficiency and power efficiency of the organic EL device of the present invention, the content of the common host material in the hole transport region is in the range of 0.1% by mass to 10% by mass. It is preferable to adjust.

《Electron transport area》
The electron transport region according to the present invention is only required to have a function of transmitting electrons injected from the cathode to the light emitting region, and as the material thereof, any one of conventionally known compounds can be selected and used. Can do. The electron transport region contains a material having a function of transporting electrons, and in a broad sense, an electron injection region (a region may be referred to as a layer) and a hole blocking region (a region may be referred to as a layer). Are also included in the electron transport region (the region may be referred to as a layer). The electron transporting region can be provided as a single layer or a plurality of regions (the region may be referred to as a layer).

  Examples of materials used for forming the electron transport region (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, Examples thereof include carbodiimide, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, and oxadiazole derivatives. Furthermore, in the 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.

Or metal complexes of 8-quinolinol derivatives, such as tris (8-quinolinol) aluminum (Alq ₃ ), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) aluminum Tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), 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, and those having the terminal substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transporting material. A distyrylpyrazine derivative can also be used as an electron transport material, and an inorganic semiconductor such as n-type-Si or n-type-SiC can also be used as an electron transport material, as in the hole injection region and the hole transport region. be able to.

  The electron transport region is preferably formed by, for example, vacuum deposition, but the above compound may be formed by applying a known thin film formation method such as spin coating, casting, or LB. Is possible.

  Moreover, from the viewpoint of improving the light emission efficiency and power efficiency of the organic EL device of the present invention, the content of the common host material in the electron transport region is in the range of 0.1% by mass to 10% by mass. It is preferable to be adjusted to.

  Also, an impurity-doped electron transport region having high n property can be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, JP-A-2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.

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

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

<Light emitting area>
The light emitting area according to the present invention will be described.

  The light emitting region according to the present invention is a layer that emits light by recombination of electrons and holes injected from an electrode, an electron transport region, a hole transport region, or the like. It may be an interface between a light emitting region and an adjacent region (may be referred to as an adjacent layer).

  As the common host material contained in the light emitting region according to the present invention, a plurality of host compounds used in conventionally known organic EL elements may be used in combination. By using a plurality of types of host compounds, it is possible to adjust the movement of charges, and the organic EL element can be made highly efficient. These known host compounds include a hole transport capability (which may have a hole blocking capability functionally), an electron transport capability, and prevent emission of longer wavelengths, and have a high Tg. The compound which is (glass transition temperature) is preferable.

  The light emitting region is formed by using, for example, the following phosphorescent compound, fluorescent compound, or the above-described common host material, for example, vacuum deposition method, spin coating method, cast method, LB method, ink jet method, etc. The film can be formed by a known thinning method.

  The film thickness as the light emitting region is not particularly limited, but is usually selected in the range of 5 nm to 5 μm, preferably 5 nm to 200 nm. This light emitting region may be one region (also referred to as a layer) containing one or more phosphorescent compounds and common host materials as described later, or a plurality of the same composition or different compositions. A laminated structure composed of regions (multiple layers) may be used.

  Moreover, from the viewpoint of improving the light emission efficiency and power efficiency of the organic EL device of the present invention, the content of the common host material in the light emitting region is in the range of 51 mass% to 99.9 mass%. It is preferable to adjust.

<Phosphorescent compound>
The phosphorescent compound according to the present invention will be described.

  The phosphorescent compound according to the present invention is a compound in which light emission from an excited triplet is observed, and is a compound having a phosphorescence quantum yield of 0.001 or more at 25 ° C. The phosphorescent quantum yield is preferably 0.01 or more, more preferably 0.1 or more.

  The phosphorescence quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of the Fourth Edition Experimental Chemistry Course 7. Although the phosphorescent quantum yield in a solution can be measured using various solvents, it is preferable that the phosphorescent compound according to the present invention achieves the above phosphorescent quantum yield in any solvent.

  The lowest excited triplet energy level T1 of the common host material according to the present invention is preferably higher than the lowest excited triplet energy level T2 of the luminescent dopant, more preferably the lowest excited triplet energy level of the luminescent dopant. It is 1.05 to 1.38 times T2.

  Further, the lowest excited triplet energy level of the common host material is preferably in the range of 284.9 kJ / mol to 377.1 kJ / mol.

  In addition, there are two types of light emission of the phosphorescent compound in principle. One is that the recombination of carriers occurs on the host compound to which carriers are transported to generate an excited state of the host compound, and this energy is generated. Energy transfer type that obtains light emission from the phosphorescent compound by transferring to the phosphorescent compound. Another is the phosphorescent compound becomes a carrier trap, and recombination of carriers on the phosphorescent compound. Occurs in the carrier trap type in which light emission from the phosphorescent compound can be obtained. In any case, the excited state energy of the phosphorescent compound must be lower than the excited state energy of the host compound. Is preferred.

  In the present invention, the phosphorescent maximum wavelength of the phosphorescent compound is not particularly limited, and in principle, by selecting a central metal, a ligand, a ligand substituent, and the like. Although the emission wavelength obtained can be changed, it is preferable that the phosphorescence emission wavelength of the phosphorescent compound has a maximum phosphorescence emission wavelength of 380 nm to 480 nm.

  Examples of such phosphorescent emission wavelengths include organic EL elements that emit blue light and organic EL elements that emit white light. These elements should be operated with lower emission voltage and lower power consumption. Can do.

  Further, by using a plurality of types of phosphorescent compounds, it is possible to mix different light emission, thereby obtaining an arbitrary emission color. White light emission is possible by adjusting the kind of phosphorescent compound and the amount of doping, and can also be applied to illumination and backlight.

  The phosphorescent compound according to the present invention is preferably used by appropriately selecting from the following organometallic complexes that exhibit phosphorescence emission (also referred to as phosphorescent compounds).

  For example, an iridium complex described in JP-A No. 2001-247859, represented by a formula as described in International Publication No. 00 / 70,655, pages 16 to 18, for example, tris (2-phenylpyridine) iridium Etc., platinum complexes such as osmium complexes or 2,3,7,8,12,13,17,18-octaethyl-21H, 23H-porphyrin platinum complexes. By using such a phosphorescent compound as a dopant, a light-emitting organic EL device having high internal quantum efficiency can be realized.

  The phosphorescent compound used in the present invention is preferably a complex compound containing any one metal belonging to Group 8, Group 9 or Group 10 of the periodic table of elements, more preferably Is an iridium compound, an osmium compound, a platinum compound (platinum complex compound), or a rare earth complex.

  Specific examples of the phosphorescent compound are shown below, but the present invention is not limited thereto.

  Moreover, each said organometallic complex may be used independently and may be used in combination of 2 or more types of compounds. These compounds are described in, for example, Inorg. Chem. Reference can be made to the method described in Vol. 40, 1704 to 1711.

  As the phosphorescent compound of the present invention, the following blue light-emitting orthometal complex is preferably used as a so-called blue light-emitting dopant in which light emission from an excited triplet is blue.

  The phosphorescent compound used in the present invention is described in, for example, Organic Letter, vol. 16, p 2579-2581 (2001), Inorganic Chemistry, Vol. 30, No. 8, 1685-1687 (1991), J. MoI. Am. Chem. Soc. , 123, 4304 (2001), Inorganic Chemistry, Vol. 40, No. 7, pages 1704-1711 (2001), Inorganic Chemistry, Vol. 41, No. 12, pages 3055-3066 (2002) , New Journal of Chemistry. 26, page 1171 (2002), and further by applying a method such as a reference described in these documents.

  In addition, for example, J. et al. Am. Chem. Soc. 123, 4304-4312 (2001), International Publication No. 00/70655 pamphlet, No. 02/15645 pamphlet, JP-A No. 2001-247859, No. 2001-345183, No. 2002-117978, 2002-170684, 2002-203678, 2002-235076, 2002-302671, 2002-324679, 2002-332291, 2002-332292, Examples include iridium complexes represented by the general formula described in JP 2002-338588 A, etc., iridium complexes exemplified as specific examples, iridium complexes represented by formula (IV) described in JP 2002-8860 A, and the like. It is done.

<Fluorescent compound>
The fluorescent compound used in the present invention will be described.

  In addition to the above-mentioned common host material, the light emitting region according to the present invention may further contain a host compound having a fluorescence maximum wavelength as a common host material. In this case, the energy transfer from the other host compound and the phosphorescent compound to the fluorescent compound allows the electroluminescence as the organic EL device to be emitted from the other host compound having the fluorescence maximum wavelength. A host compound having a fluorescence maximum wavelength is preferably a compound having a high fluorescence quantum yield in a solution state. Here, the fluorescence quantum yield is preferably 10% or more, particularly preferably 30% or more. Specific host compounds having a maximum fluorescence wavelength include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, and pyrylium dyes. Perylene dyes, stilbene dyes, polythiophene dyes, and the like. The fluorescence quantum yield can be measured by the method described in 362 (1992, Maruzen) of Spectroscopic II of the Fourth Edition Experimental Chemistry Course 7.

  The color emitted in this specification is the spectral radiance meter CS-1000 (Minolta) in FIG. 4.16 on page 108 of “New Color Science Handbook” (Edited by the Japan Society for Color Science, University of Tokyo Press, 1985). It is determined by the color when the measured result is applied to the CIE chromaticity coordinates.

《Electron injection area》
In the electron injection region according to the present invention, the content of the common host material in the electron transport region is 0.1% by mass to 10% by mass from the viewpoint of improving the light emission efficiency and power efficiency of the organic EL device of the present invention. It is preferable to adjust so that it may become this range.

《Undoped region (also called intermediate layer or intermediate region)》
The undoped region according to the present invention will be described.

  The undoped region according to the present invention includes the common host material in the entire region of the single layer A, but the hole injection region, hole transport region, light emitting region, electron transport region, electron The area | region where the injection | pouring area | region is not provided is shown.

  By including a common host material in each of the undoped region and the light emitting region, the injection barrier between the regions between the light emitting region and the undoped region (also referred to as an interlayer) is reduced, and even if the voltage (current) is changed, holes are not generated. And the effect of easily maintaining the electron injection balance.

  It has also been found that the effect of improving the color shift when a voltage (current) is applied can be obtained. Furthermore, by using a common host material in the undoped region, it was possible to eliminate the complexity of device fabrication, which is a major problem in conventional organic EL device fabrication.

  Furthermore, as described above, by using a material in which the lowest excited triplet energy level T1 of the common host material is higher than the lowest excited triplet energy level T2 of the phosphorescent compound, It was found that a triplet exciton in the light emitting region can be effectively confined in the light emitting region to obtain a highly efficient device.

  As a material constituting the undoped region, a known material may be used in combination with the common host material according to the present invention. Of the phosphorescent compounds contained in the light emitting region, a material having a larger excited triplet energy than the phosphorescent compound having the largest excited triplet energy is preferably selected as the common host material.

  For example, when a phosphorescent compound is used for each luminescent material in a blue, green, and red three-color white element, the excited triplet energy of the blue phosphorescent compound is the largest.

  It is preferable to use a common host material having an excited triplet energy larger than that of the blue phosphorescent compound.

  In the organic EL device of the present invention, since the common 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. A material having a high electric field strength dependency easily breaks the balance of hole and electron injection / transport. As the intermediate layer material and the host material, it is preferable to use a material whose mobility is less dependent on the electric field strength.

  On the other hand, in order to optimally adjust the injection balance of holes and electrons, it is also preferable that the undoped region functions as a blocking region, that is, a hole blocking region and an electron blocking region.

(When functioning as a hole blocking region)
The hole blocking region (may be referred to as a layer) is, in a broad sense, an electron transporting region (also referred to as a layer), which has a function of transporting electrons and has a very small ability to transport holes. The electron-hole recombination probability can be improved by blocking holes while transporting electrons.

  The hole blocking region has a role of blocking the holes moving from the hole transport region from reaching the cathode and a compound that can efficiently transport the electrons injected from the cathode in the direction of the light emitting region. It is formed. The physical properties required of the material constituting the hole blocking region are higher than the ionization potential of the light emitting region in order to have high electron mobility and low hole mobility and to efficiently confine holes in the light emitting region. It is preferable to have an ionization potential value or a band gap larger than that of the light emitting region. Use of at least one of styryl compounds, triazole derivatives, phenanthroline derivatives, oxadiazole derivatives, and boron derivatives as the hole blocking material is also effective in obtaining the effects of the present invention.

  Examples of other compounds include exemplified compounds described in JP-A Nos. 2003-31367, 2003-31368, and Japanese Patent No. 2721441.

(When functioning as an electronic blocking area)
On the other hand, electron blocking in the case of functioning as an electron blocking region is hole transport in a broad sense, and includes a material that has a function of transporting holes while having a remarkably small ability to transport electrons in the undoped region, By blocking electrons while transporting holes, the probability of recombination of electrons and holes can be improved.

  The hole blocking layer and the electron blocking 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. .

  Next, an injection layer (also referred to as a buffer 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) >>
In the organic EL device of the present invention, a hole injection layer is provided between the anode and the single layer A, and the hole injection layer is a hole transport material contained in the hole transport region of the single layer A. It is preferable that different hole transport materials A are included.

  Moreover, it is preferable that an electron injection layer is provided between the cathode and the single layer A, and the electron injection layer includes a material A different from the electron transport material included in the electron transport region of the single layer A.

  The injection layer (electron injection layer, hole injection layer) is also referred to as a cathode buffer layer (electron injection layer) and an anode buffer layer (hole injection layer). “Organic EL device and its industrialization front line (November 30, 1998, issued by NTS Corporation)”, Chapter 2, Chapter 2, “Electrode Materials” (123- 166)) can be used.

  As the material for forming the hole injection layer according to the present invention, a hole transport material different from the hole transport material contained in the hole transport region of the single layer A is used. For example, JP-A-9-45479 The compounds described in JP-A-9-260062, JP-A-8-288069 and the like can be used. Further, specific examples include a phthalocyanine buffer layer typified by copper phthalocyanine, an oxide buffer layer typified by vanadium oxide, an amorphous carbon buffer layer, a high polymer using a conductive polymer such as polyaniline (emeraldine) or polythiophene. Constituent materials such as a molecular buffer layer can be mentioned.

  As a material for forming the electron injection layer (cathode buffer layer) according to the present invention, a material different from the electron transport material contained in the electron transport region of the single layer A is used. For example, JP-A-6-325871 9-17574, 10-74586, etc., the details of which are described, specifically, a metal buffer layer typified by strontium and aluminum, and an alkali metal typified by lithium fluoride. Examples thereof include a compound buffer layer, an alkaline earth metal compound buffer layer typified by magnesium fluoride, and an oxide buffer layer typified by aluminum oxide. The buffer layer (injection layer) is preferably a very thin film, and the film thickness is preferably in the range of 0.1 nm to 5 μm, although it depends on the material.

"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) capable of forming a transparent conductive film may be used. For the anode, a thin film may be formed by depositing these electrode materials 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 the pattern accuracy is not required (100 μm or more) Degree), a pattern may be formed through a mask having a desired shape when the electrode material is deposited or sputtered. 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 nm to 1000 nm, preferably 10 nm to 200 nm.

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

  The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The sheet resistance as a cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 nm to 200 nm. In order to transmit the emitted light, if either one of the anode or the cathode of the organic EL element is transparent or translucent, the emission luminance is advantageously 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.

<< Substrate (also referred to as substrate, substrate, support, base, etc.) >>
The organic EL device of the present invention is preferably formed on a substrate.

  The substrate of the organic EL device of the present invention is not particularly limited to the type of glass, plastic, etc., and is not particularly limited as long as it is transparent. Examples of substrates that are preferably used include glass, quartz, A light transmissive resin film can be mentioned. 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 triacetate. Examples thereof include films having (TAC), cellulose acetate propionate (CAP) and the like. In addition, an inorganic or organic film or a hybrid film of both may be formed on the surface of the resin film.

  The external extraction efficiency at room temperature for light emission of the organic electroluminescence device of the present invention is preferably 1% or more, more preferably 5% or more. Here, the external extraction quantum efficiency (%) = the number of photons emitted to the outside of the organic EL element / the number of electrons sent to the organic EL element × 100.

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

<< Method for producing organic EL element >>
As an example of the method for producing the organic EL device of the present invention, anode / single layer A (from the anode side, hole injection region, hole transport region, undoped region, light emitting region, undoped region, then electron injection region) A method for producing an organic EL element composed of a cathode will be described.

  Although not described in this production example, in the present invention, a mode in which an electron injection layer is provided between the anode and the single layer A and a hole injection layer between the cathode and the single layer A is given as a preferable mode. It is done.

  First, a desired electrode material, for example, a thin film made of an anode material 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. Make it. Next, a single layer A is provided on this, and at this time, from the anode side, a single layer A is provided so as to have a hole injection region, a hole transport region, an undoped region, a light emitting region, an undoped region, and then an electron injection region. A layer A is formed.

  As a method for forming this single layer A, there are a vapor deposition method and a wet process (spin coating method, casting method, ink jet method, printing method) as described above, but a homogeneous film can be easily obtained and a pinhole is generated. From the standpoint of difficulty, it is particularly preferable to use a vacuum deposition method, a spin coating method, an ink jet method, or a printing method. Further, different film forming methods may be applied for each layer.

In particular, when a vapor deposition method is employed for forming the single layer A, the vapor deposition conditions vary depending on the type of compound used, but generally a boat heating temperature of 50 ° C. to 450 ° C. and a degree of vacuum of 10 ⁻⁶ Pa to 10 ⁻² Pa. The deposition rate is 0.01 nm / second to 50 nm / second, the substrate temperature is −50 ° C. to 300 ° C., the film thickness is 0.1 nm to 5 μm, preferably 5 nm to 200 nm.

  After forming the single layer A, 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 film thickness of 1 μm or less, preferably in the range of 50 to 200 nm, and a cathode is provided. Thus, a desired organic EL element can be obtained.

  The production of the organic EL device is consistently performed by evacuation once, and the entire region of the single layer A (hole injection region, hole transport region, undoped region, light emitting region, undoped region, then electron injection region) However, it may be taken out halfway and subjected to a different film forming method. At that time, it is necessary to consider that the work is performed in a dry inert gas atmosphere.

  The multi-color display device of the present invention is provided with a shadow mask only at the time of forming a light emitting region, and the other layers are common, so patterning of the shadow mask or the like is unnecessary, and vapor deposition, casting, spin coating, ink jetting on one side A film can be formed by a method, a spray method, a printing method, or the like.

  When patterning is performed only on the light emitting region, the method is not limited, but a vapor deposition method, an inkjet method, and a printing method are preferable. When using the vapor deposition method, patterning using a shadow mask may be used. Alternatively, the single layer A may be formed from the cathode side by reversing the production order.

<< Production Example of Single Layer A >>
Here, an example of the manufacturing method of the single layer A described in FIG. 7D will be described with reference to FIG.

  In order to produce the single layer A shown in FIG. 7D, for example, as shown in FIG. 8, a common host material 301a, a hole injection material 305a, a hole transport material 302a, a light emitting dopant 303a, and an electron injection material are used. Each of the vapor deposition crucibles 203a to 203e of 306a is prepared as five vapor deposition sources (may be heating boats) according to the type of material. However, in the case where a plurality of common host materials (also referred to as a plurality of compounds) are used in addition to the common host material 204a, a separate vapor deposition source is prepared corresponding to the type of the plurality of compounds.

  Since each deposition source is heated to adjust the deposition rate of each material to be appropriate, the deposition is set so as to be appropriately blocked by the shutters 202a to 202e.

  A single layer A shown in FIG. 7D is formed on a base 201 (also referred to as a base, a substrate, a base, a support, etc.) shown in FIG. It may be formed, and other constituent layers of the organic EL element may be provided on the anode.

  The shutter 202a of the vapor deposition crucible 203a filled with the common host material 301a is open at any time, and the co-vapor deposition conditions can be adjusted by opening and closing the shutters 202b to 202e of other materials as necessary.

  The case where the shutter 202e of the vapor deposition crucible 203e for the hole injection material 305a is opened is when the single layer A hole injection region 305 shown in FIG. If all the shutters 202b to 202e made of the above material are closed, the undoped region 301 made of the common host material 301a can be formed as the region of the single layer A.

  When the single layer A shown in FIG. 7D is manufactured, first, the shutters 202a and 202e of the evaporation crucibles 203a and 203e filled with the common host material 301a and the hole injection material 305a are opened, and the common host is opened. The hole injection region 305 is formed by co-evaporation so that the existence ratio of the material 301a and the hole injection material 305a in the hole injection region 305 becomes a desired ratio. Note that 200a and 200e shown in FIG. 8 represent the deposition ranges of the common host material 301a and the hole injection material 305a when the shutters 202a and 202e are opened, respectively.

  When the desired film thickness is reached, the shutter 202a of the vapor deposition crucible 203a of the common host material 301a is kept open, the shutter 202e of the vapor deposition crucible 203e filled with the hole injection material 305a is closed, and the hole transport material is closed. The shutter 202d of the vapor deposition crucible 203d filled with 302a is opened.

  The hole transport region 302 is formed by co-evaporation so that the mixing ratio of the common host material 301a and the hole transport material 302a becomes a desired ratio, and when the desired film thickness is reached, the shutter 202a of the common host material 301a is The shutter 202d of the vapor deposition crucible 203d filled with the hole transport material 302a is closed while being opened, and the undoped region 301 is formed so as to optimize the carrier injection balance.

  Next, the shutter 202c of the vapor deposition crucible 203c filled with the light emitting dopant 303a is opened. The light-emitting region 303 is formed by co-evaporation so that the mixing ratio of the common host material 301a and the light-emitting dopant 303a becomes a desired ratio, and when the desired film thickness is reached, the evaporation crucible 203a filled with the common host material 301a. The shutter 202a of the deposition crucible 203c filled with the light-emitting dopant 303a is closed while the shutter 202a of the substrate 202 is open, and the region 202 containing only the common host material and the undoped region 301 (this region has a hole blocking function). It is preferable to adjust the thickness and the like.

  When the desired film thickness is reached, the shutter 202b of the vapor deposition crucible 203b filled with the electron injection material 306a is opened, and the electron injection region 306 is formed by co-evaporation so as to obtain a desired ratio.

  When a plurality of light emitting regions are provided or when a plurality of light emitting dopants are co-evaporated, a crucible for the light emitting dopant may be further provided, and the light emitting regions may be further provided as described above. In order to confine excitons and prevent color misregistration, when a region only for the common host (undoped region) is provided between the light emitting region and the light emitting region, it is only necessary to close the shutter other than the common host.

  As a simpler method, the common host material 301a, the hole injection material 305a, the hole transport material 302a, the light emitting dopant 303a, and the electron injection material 306a are evaporated from a vapor deposition source (not shown) arranged in parallel. This method is also effective. A similar element configuration can be produced by moving the substrate at a predetermined speed.

  This is also a production method that can be achieved by including the common host material A in the single layer A.

<< Display device, lighting device >>
The organic EL element of the present invention may be used as one 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). 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 manufactured by using three or more organic EL elements of the present invention having different emission colors. Alternatively, it is possible to make a single color emission color, for example, white emission, into BGR using a color filter to achieve full color. Further, it is possible to convert the emission color of the organic EL to another color by using a color conversion filter, and in this case, λmax of the organic EL emission is preferably 480 nm or less.

  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. An alternating voltage may be applied. The alternating current waveform to be applied may be arbitrary.

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

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

  The lighting device of the present invention includes 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 sensors Although a light source etc. are mentioned, it is not limited to this.

  Further, the organic EL element according to the present invention may be used as an organic EL element having a resonator structure.

  Examples of the purpose of use of the organic EL element having such a resonator structure include a light source of an optical storage medium, a light source of an electrophotographic copying machine, a light source of an optical communication processing machine, and a light source of an optical sensor. It is not limited. Moreover, you may use for the said use by making a laser oscillation.

  An example of a display device having the organic EL element of the present invention as a configuration 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 the plurality of pixels based on image information from the outside. The pixels for each scanning line are converted into image data signals by the scanning signal. In response to this, light is sequentially emitted and image scanning is performed to display image information on the display unit A.

  FIG. 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 shows 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 organic EL element 10 emits light by the switching transistor 11 and the drive transistor 12 that are active elements for the organic EL element 10 of each of the plurality of pixels, and the light emission of the organic EL element 10 of each of the plurality of pixels 3. It is carried out. Such a light emitting method is called an active matrix method.

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

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

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

  FIG. 4 is a schematic view 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 element material of 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. As a combination of a plurality of luminescent colors, those containing three luminescence maximum wavelengths of three primary colors of blue, green, and blue may be used. 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 fluorescent or phosphorescent light, 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 electroluminescence device according to the present invention, a method of combining a plurality of light-emitting dopants is preferable.

  As a layer structure of an organic electroluminescence device for obtaining a plurality of emission colors, there are a method in which a plurality of emission dopants exist in one emission region, a plurality of emission regions, and an emission wavelength in each emission region. And a method of forming minute pixels emitting light having different wavelengths in a matrix.

  In the white organic electroluminescence device according to the present invention, patterning may be performed by a metal mask, an ink jet printing method, or the like at the time of film formation, if necessary. When patterning, only the electrode may be patterned, the electrode and the light emitting region may be patterned, or the entire element layer may be patterned.

  The light emitting material used in the light emitting region 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 or a publicly known one is adapted so as to conform to the wavelength range corresponding to the CF (color filter) characteristics. Any one of the light emitting materials may be selected and combined to be whitened.

  Thus, in addition to the display device and display, the white light-emitting organic EL element of the present invention can be used as a kind of lamp such as a home lighting, an interior lighting, and an exposure light source as various light emitting light sources and lighting devices. It is also useful for display devices such as backlights of liquid crystal display devices.

  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 is given and this invention is demonstrated, this invention is not limited to these. A list of compounds used in the examples is shown below.

Example 1
<< Production of Organic EL Element 1-1 >>
Transparent support provided with this ITO transparent electrode after patterning on a substrate (NH45 manufactured by NH Techno Glass) made of ITO (indium tin oxide) with a thickness of 100 nm on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode The substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes. This transparent support substrate was fixed to a substrate holder of a commercially available vacuum deposition apparatus. However, the crucible for vapor deposition in the vapor deposition apparatus was set as shown in FIG. 8, and α-NPD, compound 189, and Ir-1 were respectively filled in the optimum amounts for device fabrication. The crucible for vapor deposition was made of molybdenum resistance heating material.

Next, after reducing the vacuum chamber to 4 × 10 ⁻⁴ Pa, the deposition crucible containing α-NPD, compound 189, and Ir-1 was energized and heated, and the material ratios shown in Tables 1 and 2 were obtained. A single layer A was formed by co-evaporation or single vapor deposition so as to be (also referred to as a mixing ratio). In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Subsequently, magnesium and silver were vapor-deposited at a molar ratio of 10: 1 to form a cathode, and an organic EL device 1-1 was produced.

<< Production of Organic EL Element 1-2 >>
Transparent support provided with this ITO transparent electrode after patterning on a substrate (NH45 manufactured by NH Techno Glass) made of ITO (indium tin oxide) with a thickness of 100 nm on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode The substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes. This transparent support substrate was fixed to a substrate holder of a commercially available vacuum deposition apparatus. However, the crucible for vapor deposition in the vapor deposition apparatus was set as shown in FIG. 8, and CuPc (copper phthalocyanine), α-NPD, compound 189, Ir-1, and Alq ₃ were respectively filled in the optimum amounts for device fabrication. The crucible for vapor deposition was made of molybdenum resistance heating material.

The vacuum chamber was then depressurized to 4 × 10 ⁻⁴ Pa, heated by energizing the vapor deposition crucible containing CuPc, and vapor-deposited on a transparent support substrate at a vapor deposition rate of 0.1 nm / sec. A layer was provided.

  Further, the vapor deposition crucible containing α-NPD, compound 189, and Ir-1 is energized and heated, and a single layer A is formed by co-evaporation or single vapor deposition at the mixing ratios shown in Tables 1 and 2. did.

Further, the deposition crucible containing Alq ₃ was energized and heated, and deposited on the single layer A at a deposition rate of 0.1 nm / second to provide an electron transport layer.

  In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Subsequently, 0.5 nm of lithium fluoride was vapor-deposited as an electron injection layer, and further, 110 nm of aluminum was vapor-deposited to form a cathode, thereby producing an organic EL element 1-2.

<< Production of Organic EL Elements 1-3 to 1-5 >>
In the production of the organic EL element 1-2, organic EL elements 1-3 to 1-5 were produced in the same manner except that the material, film thickness, and mass ratio were changed as shown in Tables 1 and 2.

<< Production of Organic EL Element 1-6 >>
Transparent support provided with this ITO transparent electrode after patterning on a substrate (NH45 manufactured by NH Techno Glass) made of ITO (indium tin oxide) with a thickness of 100 nm on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode The substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

On this transparent support substrate, a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS: Bayer, Baytron P Al 4083) to 70% with pure water at 3000 rpm for 30 seconds. After film formation by spin coating, the film was dried at 200 ° C. for 1 hour to provide a 30 nm hole injection layer. This transparent support substrate was fixed to a substrate holder of a commercially available vacuum deposition apparatus. However, the crucible for vapor deposition in the vapor deposition apparatus was set as shown in FIG. 8, and α-NPD, compound 189, Ir-1, and Alq ₃ were respectively filled in the optimum amounts for device fabrication. The crucible for vapor deposition was made of molybdenum resistance heating material.

Next, after reducing the vacuum chamber to 4 × 10 ⁻⁴ Pa, the deposition crucible containing α-NPD, compound 189, and Ir-1 was energized and heated, and the mixing ratios shown in Tables 1 and 2 were obtained. A single layer A was formed by co-evaporation or single vapor deposition.

Further, the deposition crucible containing Alq ₃ was energized and heated, and deposited on the single layer A at a deposition rate of 0.1 nm / second to provide an electron transport layer. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Then, 0.5 nm of lithium fluoride was vapor-deposited as an electron injection layer, and also 110 nm of aluminum was vapor-deposited, the cathode was formed, and the organic EL element 1-6 was produced.

<< Production of Organic EL Elements 1-7 and 1-8 >>
In the organic EL element 1-1, the organic EL element 1-7 was produced in the same manner except that Alq ₃ was changed to BCP: Cs (75:25) and LiF was not deposited. Further, an organic EL element 1-8 was produced in the same manner as 1-7 except that the common host material was changed from the compound 189 to CDBP in the production of the organic EL element 1-7.

<< Production of Organic EL Element 1-9 >>
Transparent support provided with this ITO transparent electrode after patterning on a substrate (NH45 manufactured by NH Techno Glass) made of ITO (indium tin oxide) with a thickness of 100 nm on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode The substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes. This transparent support substrate was fixed to a substrate holder of a commercially available vacuum deposition apparatus. However, the crucible for vapor deposition in the vapor deposition apparatus was set as shown in FIG. 8, and CuPc (copper phthalocyanine), α-NPD, compound 189, Ir-1, and Alq ₃ were respectively filled in the optimum amounts for device fabrication. . The crucible for vapor deposition was made of molybdenum resistance heating material. Next, the pressure in the vacuum chamber was reduced to 4 × 10 ⁻⁴ Pa, and then the evaporation crucible containing CuPc (copper phthalocyanine), α-NPD, compound 189, Ir-1, and Alq ₃ was energized and heated. 1. A single layer A was formed by co-evaporation or single vapor deposition so that the mixing ratios shown in Table 2 were obtained. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Subsequently, 0.5 nm of lithium fluoride was vapor-deposited as an electron injection layer, and further, 110 nm of aluminum was vapor-deposited to form a cathode, thereby producing an organic EL element 1-9.

<< Production of Organic EL Elements 1-10 to 1-13 >>
Organic EL elements 1-10 to 1-13 were produced in the same manner except that the materials, film thickness, mass ratio, each region, etc. were changed as shown in Tables 1 and 2 in the organic EL element 1-9. .

<< Preparation of Organic EL Element 1-14 >> Comparative Example without Single Layer A Substrate (100 mm × 100 mm × 1.1 mm glass substrate made of ITO (Indium Tin Oxide) as a film having a thickness of 100 nm (made by NH Techno Glass) After patterning NA45), the transparent support substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes. This transparent support substrate was fixed to a substrate holder of a commercially available vacuum deposition apparatus. However, the crucible for vapor deposition in the vapor deposition apparatus was set as shown in FIG. 8, and CuPc (copper phthalocyanine), α-NPD, Ir-1, Alq ₃ , and LiF were respectively filled in the optimum amounts for device fabrication. The crucible for vapor deposition was made of molybdenum resistance heating material.

The vacuum chamber was then depressurized to 4 × 10 ⁻⁴ Pa, heated by energizing the vapor deposition crucible containing CuPc, and vapor-deposited on a transparent support substrate at a vapor deposition rate of 0.1 nm / sec. A layer was provided.

Furthermore, the deposition crucible containing α-NPD, Ir-1, Alq ₃ , and LiF was heated by energization, and the α-NPD content was gradually reduced from 100% to 0%, and the content of Alq ₃ + LiF was decreased. The vapor deposition rate was adjusted so that the mixing ratio gradually decreased from 0% to 100%, and Ir-1 was always co-deposited so as to be 5% by mass to provide a mixed light emitting layer.

  Subsequently, 110 nm of aluminum was vapor-deposited to form a cathode, and a comparative organic EL element 1-14 was produced.

<< Preparation of Organic EL Element 1-15 >>: Comparative Example without Single Layer A Substrate (100 mm × 100 mm × 1.1 mm glass substrate made of ITO (indium tin oxide) as a film of 100 nm as an anode (manufactured by NH Techno Glass) After patterning NA45), the transparent support substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes. This transparent support substrate was fixed to a substrate holder of a commercially available vacuum deposition apparatus. However, the crucible for vapor deposition in the vapor deposition apparatus was set as shown in FIG. 8, and α-NPD, Ir-1, Alq ₃ , and BCP were respectively filled in the optimum amounts for device fabrication. The crucible for vapor deposition was made of molybdenum resistance heating material.

Next, after the pressure in the vacuum chamber was reduced to 4 × 10 ⁻⁴ Pa, the evaporation crucible containing α-NPD, Ir-1 and Alq ₃ was energized and heated, and the mixing mass ratio was (47: 47: 6 ) To form a mixed light emitting layer of 70 nm. Thereafter, the evaporation crucible containing α-NPD, Alq ₃ , and BCP is energized and heated, and co-deposited so that the mixing mass ratio becomes (1: 1: 1) to provide a mixed layer of 30 nm. Subsequently, LiF 1 nm was vapor-deposited as an electron injection layer, and further, aluminum 110 nm was vapor-deposited to form a cathode, thereby producing an organic EL element 1-15 of a comparative example.

<< Preparation of Organic EL Element 1-16 >>: Comparative Example without Single Layer A Substrate (100 mm × 100 mm × 1.1 mm glass substrate made of ITO (indium tin oxide) as a film having a thickness of 100 nm (made by NH Techno Glass) After patterning NA45), the transparent support substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes. This transparent support substrate was fixed to a substrate holder of a commercially available vacuum deposition apparatus. However, CuPc (copper phthalocyanine), α-NPD, Ir-1, CBP, Alq ₃ , and compound 189 were each filled in an optimum amount for device fabrication in each of the deposition crucibles in the deposition apparatus. The crucible for vapor deposition was made of molybdenum resistance heating material.

Next, after reducing the pressure of the vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat containing CuPc was energized and heated, and deposited on the transparent support substrate at a deposition rate of 0.1 nm / second to form a 20 nm hole injection layer. Was provided.

  Next, the heating boat containing α-NPD was energized and heated, and deposited on the hole injection layer at a deposition rate of 0.1 nm / second to provide a 20 nm hole transport layer. Further, the heating boat containing CBP and Ir-1 was energized and heated, and co-deposited on the hole transport layer at a deposition rate of 0.2 nm / second and 0.01 nm / second, respectively, to obtain a 35 nm light emitting layer. Was provided.

Further, the heating boat containing the compound 189 is energized and heated, and is deposited on the light emitting layer at a deposition rate of 0.1 nm / second to provide a 10 nm thick hole blocking layer, and further contains Alq ₃ . The heating boat was energized and heated, and deposited on the hole blocking layer at a deposition rate of 0.1 nm / second to provide an electron transport layer having a thickness of 40 nm. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Subsequently, 0.5 nm of lithium fluoride was vapor-deposited as an electron injection layer, and further, 110 nm of aluminum was vapor-deposited to form a cathode, thereby producing a comparative organic EL element 1-16.

<< Evaluation of Organic EL Elements 1-1 to 1-16 >>
About each produced element, as described below, external extraction quantum efficiency, light emission lifetime, and power efficiency were evaluated, respectively.

《External extraction quantum efficiency》
About the produced organic EL elements 1-1 to 1-16, the external extraction quantum efficiency (%) was measured when a constant current of ^2.5 mA / cm ² was applied at 23 ° C. in a dry nitrogen gas atmosphere. For the measurement, a spectral radiance meter CS-1000 (manufactured by Konica Minolta) was used.

《Luminescence life, power efficiency》
When driving at a constant current of ^2.5 mA / cm ² , the time required for the luminance to drop to half of the luminance immediately after the start of light emission (initial luminance) was measured, and this was calculated as the half-life time (τ 0.5). As an index of life. For the measurement, a spectral radiance meter CS-1000 (manufactured by Konica Minolta) was used. Further, power efficiency (lumens / W) was measured as an index of lowering drive voltage and power consumption.

  The obtained results are shown in Table 3. Here, the measurement results of the external extraction quantum efficiency, power efficiency, and light emission lifetime are expressed as relative values when the measured value of the organic EL element 1-16 (comparative example) is 100.

  The obtained results are shown in Table 3.

  From Table 3, it can be seen that, compared with the comparison, the organic EL device of the present invention exhibits excellent performance in terms of external extraction quantum efficiency, power efficiency, and light emission lifetime.

Example 2: White light-emitting organic EL element << Preparation of organic EL element 2-1 >>
In the production of the organic EL element 1-7 of Example 1, a white organic EL was produced in the same manner as in 1-7 except that the light emitting region and the undoped region were formed with the materials, film thicknesses, and mass ratios shown in Tables 4 and 5. Element 2-1 was produced.

<< Production of Organic EL Elements 2-2 to 2-5 >>
In the organic EL element 1-11, the white organic EL elements 2-2 to 2-2 are the same as the 1-7 except that the light emitting region and the undoped region are formed with the materials, film thicknesses, and mass ratios shown in Tables 4 and 5. -5 was produced.

<< Production of Organic EL Elements 2-6 and 2-7 >>
In the organic EL element 1-12, white organic EL elements 2-6, 2 and 2 were formed in the same manner as in 1-7, except that the light emitting region and the undoped region were formed with the materials, film thicknesses, and mass ratios shown in Tables 4 and 5. -7 was produced.

<< Preparation of Organic EL Element 2-8 >>: Comparative Example Without Single Layer A In preparation of organic EL element 1-17 (comparative example) of Example 1, as a light emitting layer, CBP: TPB = 97: 3 (mass ratio) ) Layer (film thickness 12 nm), CBP: Ir-1 = 94: 6 (mass ratio) layer (film thickness 12 nm), CBP: Ir-9 = 92; 8 (mass ratio) layer (film) An organic EL element 2-8 was produced in the same manner except that the thickness was changed to 12 nm.

<< Preparation of Organic EL Element 2-9 >>: Comparative Example without Single Layer A A layer containing CBP: TPB = 97: 3 (mass ratio) was used as the light emitting layer in the preparation of organic EL element 2-8. NPD: rubrene = 99: 1 (mass ratio) changed to a layer (film thickness 7 nm), no CBP: Ir-1 = 94: 6 (mass ratio) layer was provided, and CBP: Ir-9 = 92; The layer containing 8 (mass ratio) is changed to a layer containing DPVBi: BCzVBi = 88: 12 (mass ratio) (film thickness 27 nm), and further changed to BCP: Cs (75:25) instead of Alq ₃ , An organic EL device 2-9 was produced in the same manner except that LiF was not deposited.

<< Evaluation of organic EL elements >>
The obtained organic EL elements 2-1 to 2-9 were similarly evaluated for external extraction quantum efficiency and power efficiency described in Example 1.

  The results obtained are shown in Table 6. Moreover, the evaluation result was represented with the relative value when the measured value of the organic EL element 2-8 was set to 100.

  From Table 6, it can be seen that, compared with the comparison, the organic EL device of the present invention exhibits excellent performance in both external extraction quantum efficiency and power efficiency.

Example 3
In the production of the white light emitting organic EL elements 2-1 to 2-7, the same light emitting region is further provided on the light emitting region in the single layer A (however, when the light emitting region is a plurality of regions, a plurality of corresponding light emitting regions are provided. Organic EL elements 3-1 to 3-7 were fabricated in the same manner except that a light emitting region was provided. Incidentally, the space between the anode and the cathode is formed of only a single layer A, and from the anode side, a hole injection region (having a P-type semiconductor function), a hole transport region, a plurality of light emitting regions and a plurality of undoped regions. Next, an example of an organic EL element having a single layer A in which electron injection regions (having an N-type semiconductor function) are formed is shown in FIG. 9 as a schematic diagram.

  The obtained organic EL elements 3-1 to 3-7 were improved in color shift at high voltage as compared with the organic EL elements 2-1 to 2-7.

Example 4
<Production of white lighting device>
The non-light-emitting surfaces of the organic EL elements 2-1 to 2-7 (all of the present invention) obtained in Example 2 were covered with a glass case to obtain an illumination device as shown in FIGS. The illuminating device could be used as a thin illuminating device that emits white light with high luminous efficiency and long emission life. FIG. 5 shows a schematic diagram of the lighting device, and the organic EL element 101 is covered with a glass cover 102. The sealing operation with the glass cover is performed under a nitrogen atmosphere without bringing the organic EL element 101 into contact with the atmosphere. Glove box (performed in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more). 6 shows a cross-sectional view of the lighting device. In FIG. 6, reference numeral 105 denotes a cathode, 106 denotes an organic EL layer, and 107 denotes a glass substrate with a transparent electrode. The glass cover 102 is filled with nitrogen gas 108 and a water catching agent 109 is provided.

  When the obtained illuminating device was energized, almost white light was obtained, and it was found that the illuminating device could be used.

  According to the present invention, there is provided an organic EL element, a lighting device and a display device having a low voltage due to a low resistance of an organic layer and a structure having excellent electro-optical characteristics with high luminous efficiency, and further a long life. It was possible to provide an organic EL element, a lighting device and a display device.

Claims (5)

Having a single layer A containing at least one common host material between the anode and the cathode;
The single layer A is composed of a hole transport region containing at least one kind of hole transport material, a light emitting region containing at least one kind of light emitting dopant, and only the common host material from the side close to the anode. And an undoped region
The hole transport region and the light emitting region do not have a region overlapping with each other, and the entire region of the single layer A contains 0.1% by mass or more of the common host material,
The content of the common host material is approximately constant in each region;
At least one of the light-emitting dopants is a phosphorescent compound, wherein the organic electroluminescence element. The organic electroluminescence device according to claim 1 , wherein at least one of the common host materials is a compound represented by the following general formula (1).
[Wherein, Z ₁ represents an aromatic heterocyclic ring which may have a substituent, Z ₂ represents an aromatic heterocyclic ring or an aromatic hydrocarbon ring which may each have a substituent, Z ₃ represents a divalent linking group or a simple bond. R ₁₀₁ represents a hydrogen atom or a substituent. ] The organic electroluminescence device according to claim 1, which emits white light. A display device comprising the organic electroluminescence element according to claim 1 . It has an organic electroluminescent element as described in any one of Claims 1-3 , The illuminating device characterized by the above-mentioned.