JP4603624B1 - Organic electroluminescence device - Google Patents

Abstract

The present invention provides an organic electroluminescence device capable of improving device performance such as luminous efficiency, driving voltage, and driving durability and suppressing chromaticity change at the time of device degradation.
An organic layer including at least one light-emitting layer 6 and a cathode-side adjacent layer 7 adjacent to the cathode side of the light-emitting layer is provided between an anode 2 and a cathode 10, The light emitting layer contains a red phosphorescent light emitting material and a host material composed of at least one of a compound having an anthracene derivative skeleton and a compound having a pyrene derivative skeleton, and the cathode side adjacent layer has a non-nitrogen containing anthracene derivative skeleton An organic electroluminescent device comprising at least one of a compound and a compound having a pyrene derivative skeleton.
[Selection] Figure 1

Description

  The present invention relates to an organic electroluminescent device (hereinafter also referred to as “organic electroluminescence device” or “organic EL device”).

  Organic electroluminescence devices have features such as self-emission and high-speed response, and are expected to be applied to flat panel displays. Especially, organic thin film (hole transport layer) and electron transport Since the report of a two-layer type (laminated type) in which an organic thin film (electron transport layer) is laminated, it has attracted attention as a large-area light-emitting element that emits light at a low voltage of 10 V or less. The stacked organic electroluminescent element has a basic structure of positive electrode / hole transport layer / light emitting layer / electron transport layer / negative electrode, and the light emitting layer includes the hole transport as in the case of the two-layer type. The layer or the electron transport layer may serve as its function.

In such an organic electroluminescent device, various studies have been made in order to improve device performance such as luminous efficiency, driving voltage, and driving durability.
For example, Patent Document 1 proposes a condensed aromatic ring compound having a large number of pyrene skeletons and anthracene skeletons as a host material constituting a phosphorescent material in combination with a phosphorescent dopant. In Example 86 of Patent Document 1, a compound having an anthracene skeleton is used as the host material of the light emitting layer, and a nitrogen-containing anthracene compound is used in the cathode side adjacent layer of the light emitting layer.
Patent Document 2 includes an anode, a cathode, and an organic thin film layer provided between the anode and the cathode, and the organic thin film layer is a substituted or unsubstituted polycyclic condensed aromatic. A light-emitting layer having a first polycyclic fused aromatic compound having a skeleton and a first phosphorescent material that exhibits phosphorescence; a substituted or unsubstituted polycyclic ring on the cathode side of the light-emitting layer; An organic electroluminescent device comprising an organic layer containing a second polycyclic fused aromatic compound having a formula fused aromatic skeleton has been proposed.

  However, when each of the techniques described in these prior art documents is used alone, the interface deterioration between the light emitting layer and the cathode side adjacent layer occurs, and this interface deterioration greatly changes the light emission distribution because the carrier balance is greatly changed. There is a problem that chromaticity change occurs when the element deteriorates. Accordingly, there is a demand for prompt provision of an organic electroluminescence device capable of suppressing changes in chromaticity at the time of device degradation and achieving improved device performance such as light emission efficiency, drive voltage, and drive durability. It is.

JP 2009-16669 A JP 2009-147324 A

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, an object of the present invention is to provide an organic electroluminescence device capable of improving device performance such as light emission efficiency, driving voltage, and driving durability and suppressing chromaticity change at the time of device deterioration.

  As a result of intensive studies by the present inventors in order to solve the above problems, a compound having an anthracene derivative skeleton and a compound having a pyrene derivative skeleton are used as both the host material of the light emitting layer and the cathode side adjacent layer material of the light emitting layer. It has been found that the use improves the device performance such as luminous efficiency, drive voltage, and drive durability, and can suppress the chromaticity change at the time of device deterioration.

The present invention is based on the above findings by the present inventors, and means for solving the above problems are as follows. That is,
<1> An organic layer including at least one light-emitting layer and a cathode-side adjacent layer adjacent to the cathode side of the light-emitting layer between the anode and the cathode,
The light emitting layer contains a red phosphorescent light emitting material and a host material composed of at least one of a compound having an anthracene derivative skeleton and a compound having a pyrene derivative skeleton,
The organic electroluminescent device is characterized in that the cathode side adjacent layer contains at least one of a compound having a non-nitrogen-containing anthracene derivative skeleton and a compound having a pyrene derivative skeleton.
<2> The organic electroluminescence device according to <1>, wherein the compound having an anthracene derivative skeleton in the light emitting layer and the cathode side adjacent layer is represented by the following general formula (I).
However, in the general formula (I), Ar ¹ and Ar ² are each independently a group derived from a substituted or unsubstituted aromatic ring having 6 to 20 nuclear carbon atoms. The aromatic ring may be substituted with one or more substituents. The substituent is a substituted or unsubstituted aryl group having 6 to 50 nuclear carbon atoms, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 50 carbon atoms, a substituted group. Or an unsubstituted alkoxy group having 1 to 50 carbon atoms, a substituted or unsubstituted aralkyl group having 6 to 50 nuclear carbon atoms, a substituted or unsubstituted aryloxy group having 5 to 50 nuclear atoms, a substituted or unsubstituted nucleus. It is selected from an arylthio group having 5 to 50 atoms, a substituted or unsubstituted alkoxycarbonyl group having 1 to 50 carbon atoms, a substituted or unsubstituted silyl group, a carboxyl group, a halogen atom, a cyano group, a nitro group, and a hydroxy group. When the aromatic ring is substituted with two or more substituents, the substituents may be the same or different, and adjacent substituents are bonded to each other to form a saturated or unsaturated cyclic structure. May be formed.
R ¹ to R ⁸ are each a hydrogen atom, a substituted or unsubstituted aryl group having 6 to 50 nuclear carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 50 nuclear atoms, a substituted or unsubstituted carbon atom having 1 to 50 alkyl groups, substituted or unsubstituted cycloalkyl groups having 3 to 50 carbon atoms, substituted or unsubstituted alkoxy groups having 1 to 50 carbon atoms, substituted or unsubstituted aralkyl groups having 6 to 50 carbon atoms, substituted or Unsubstituted aryloxy group having 5 to 50 nuclear atoms, substituted or unsubstituted arylthio group having 5 to 50 nuclear atoms, substituted or unsubstituted alkoxycarbonyl group having 1 to 50 carbon atoms, substituted or unsubstituted silyl group Group, carboxyl group, halogen atom, cyano group, nitro group and hydroxy group. Further, adjacent substituents may be bonded to each other to form a saturated or unsaturated cyclic structure.
<3> The organic electroluminescence device according to any one of <1> to <2>, wherein the compound having a pyrene derivative skeleton in the light emitting layer and the cathode side adjacent layer is represented by the following general formula (II).
However, in the general formula (II), Ar ^1a and Ar ^2a each represent a substituted or unsubstituted aromatic ring group having 6 to 50 nuclear carbon atoms.
L is a substituted or unsubstituted phenylene group, a substituted or unsubstituted naphthalenylene group, a substituted or unsubstituted fluorenylene group, or a substituted or unsubstituted dibenzosilolylene group, respectively.
m is an integer of 0 to 2, nb is an integer of 1 to 4, s is an integer of 0 to 2, and t is an integer of 0 to 4.
L or Ar ^1a is bonded to any one of positions 1 to 5 of pyrene, and L or Ar ^2a is bonded to any of positions 6 to 10 of pyrene.
However, when nb + t is an even number, Ar ^1a , Ar ^2a , and L satisfy the following (1) or (2).
(1) Ar ^1a ≠ Ar ^2a (where ≠ indicates a group having a different structure)
(2) When Ar ^1a = Ar ^2a (2-1) When m ≠ s and / or nb ≠ t, or (2-2) When m = s and nb = t,
(2-2-1) L or pyrene are bonded to different bonding positions on Ar ^1a and Ar ^2a , respectively.
(2-2-2) L, or pyrene, ^{Ar 1a} and when attached to the same bonding position on ^{Ar 2a,} L, or a substituted position in the pyrene ^{Ar 1a} and ^{Ar 2a} is 1-position and 6-position, Or it is not the 2nd and 7th positions.
<4> The compound having an anthracene derivative skeleton in the light emitting layer and the cathode side adjacent layer is a compound having an unsubstituted anthracene derivative skeleton,
The organic electroluminescence device according to any one of <1> to <3>, wherein the compound having a pyrene derivative skeleton in the light emitting layer and the cathode side adjacent layer is a compound having an unsubstituted pyrene derivative skeleton.
<5> The compound having a non-nitrogen-containing anthracene derivative skeleton in the cathode-side adjacent layer is a non-nitrogen-containing anthracene derivative compound having no lone electron pair, and the compound having a pyrene derivative skeleton in the cathode-side adjacent layer is a lone electron pair The organic electroluminescence device according to any one of <1> to <4>, wherein the organic electroluminescence device is a compound having a pyrene derivative skeleton that does not contain any of.
<6> The anthracene derivative skeleton in the light emitting layer is a non-nitrogen-containing anthracene derivative compound having no lone electron pair, and the compound having a pyrene derivative skeleton in the light emitting layer is a compound having a pyrene derivative skeleton having no lone electron pair. The organic electroluminescence device according to any one of <1> to <5>.
<7> Any one of <1> to <6>, wherein the red phosphorescent material is an organometallic complex in which the central metal is at least one of ruthenium, rhodium, palladium, tungsten, rhenium, osmium, iridium, and platinum. It is an organic electroluminescent element as described in above.
<8> The organic electroluminescence device according to any one of <1> to <7>, wherein the cathode side adjacent layer has a thickness of 1 nm to 10 nm.

Usually, a change in chromaticity at the time of device deterioration in an organic electroluminescent device is caused by a change in light emission distribution. In the organic electroluminescent device of the present invention, a compound having an anthracene derivative skeleton and a compound having a pyrene derivative skeleton are used. By using it as both the host material of the light emitting layer and the cathode side adjacent layer material of the light emitting layer, the change in the light emission distribution before and after the deterioration becomes small, and the change in chromaticity when the element deteriorates can be suppressed.
As a factor of the change in light emission distribution before and after the deterioration, there is deterioration of the interface between the light emitting layer and the cathode side adjacent layer of the light emitting layer. Interfacial deterioration greatly changes the carrier balance and changes the light emission distribution, resulting in a change in chromaticity. As a cause of interface deterioration, a chemical reaction between a phosphorescent material, a host material, and a cathode-side adjacent layer material has been pointed out (see Scholz et al 2007, Scholz et al 2009).
In the organic electroluminescence device of the present invention, a compound having an anthracene derivative skeleton and a compound having a pyrene derivative skeleton (particularly, a compound having no nitrogen, no lone pair, and no substituent) are used as a host material and a light emitting layer of the light emitting layer. By using it as both the cathode side adjacent layer material of the layer, it is presumed that the chemical reaction between the phosphorescent material, the host material and the cathode side adjacent layer material hardly occurs and the interface deterioration is suppressed.

  According to the present invention, there is provided an organic electroluminescent device capable of solving conventional problems, improving device performance such as light emission efficiency, drive voltage, and drive durability, and suppressing chromaticity change at the time of device deterioration. Can be provided.

FIG. 1 is a schematic view showing an example of the layer structure of the organic electroluminescent element of the present invention.

(Organic electroluminescent device)
The organic electroluminescent element of the present invention has an organic layer including at least one light emitting layer and at least a cathode side adjacent layer adjacent to the cathode side of the light emitting layer between the anode and the cathode, and It has other layers as needed.

<Light emitting layer>
The material, shape, structure, size, etc. of the light emitting layer are not particularly limited and can be appropriately selected according to the purpose. Examples of the shape include a film shape, a sheet shape, In addition, examples of the planar shape include a quadrangle and a circle, and examples of the structure include a single layer structure and a laminated structure. The size can be appropriately selected depending on the application.

  The light emitting layer contains a red phosphorescent light emitting material and a host material.

-Red phosphorescent material-
The red phosphorescent material preferably has a peak wavelength of 580 nm to 640 nm.
The red phosphorescent material is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include complexes containing transition metal atoms and lanthanoid atoms.
Examples of the transition metal atom include ruthenium, rhodium, palladium, tungsten, rhenium, osmium, iridium, platinum, and the like. Among these, rhenium, iridium, and platinum are preferable, and iridium and platinum are particularly preferable.

Examples of the lanthanoid atom include lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. Among these, neodymium, europium, and gadolinium are particularly preferable.
Examples of the ligand of the complex include G.I. Wilkinson et al., Comprehensive Coordination Chemistry, Pergamon Press, 1987, H.C. Listed by Yersin, “Photochemistry and Photophysics of Coordination Compounds”, published by Springer-Verlag, 1987, Akio Yamamoto, “Organic Metal Chemistry-Fundamentals and Applications,” published by Soukabo, 1982, etc. It is done.
Specific ligands include halogen ligands (preferably chlorine ligands), aromatic carbocyclic ligands (eg, cyclopentadienyl anion, benzene anion, naphthyl anion, etc.), nitrogen-containing hetero Ring ligands (eg, phenylpyridine, benzoquinoline, quinolinol, bipyridyl, or phenanthroline), diketone ligands (eg, acetylacetone, etc.), carboxylic acid ligands (eg, acetic acid ligands, etc.), alcoholates Examples include ligands (eg, phenolate ligands), carbon monoxide ligands, isonitrile ligands, cyano ligands, and the like. Among these, a nitrogen-containing heterocyclic ligand is particularly preferable.

The complex may have one transition metal atom in the compound, or may be a so-called binuclear complex having two or more. Different metal atoms may be contained at the same time.
Specific examples of the phosphorescent material that is a complex containing platinum include, but are not limited to, the following compounds.

There is no restriction | limiting in particular as a phosphorescence-emitting material which is the said complex containing iridium, Although it can select suitably according to the objective, It represents with either of following General formula (2), (3) and (4) It is preferable that it is a compound.
However, in said general formula (2), (3) and (4), n represents the integer of 1-3. XY represents a bidentate ligand. Ring A represents a ring structure that may contain any of a nitrogen atom, a sulfur atom, and an oxygen atom. R ¹¹ represents a substituent, and m1 represents an integer of 0 to 6. When m1 is 2 or more, adjacent R ¹¹ may be bonded to form a ring which may contain any of a nitrogen atom, a sulfur atom and an oxygen atom, and the ring is further substituted with a substituent. May be. R ¹² represents a substituent, and m2 represents an integer of 0 to 4. When m2 is 2 or more, adjacent R ¹² may be bonded to form a ring which may contain any of a nitrogen atom, a sulfur atom and an oxygen atom, and the ring is further substituted with a substituent. May be. R ¹¹ and R ¹² may combine to form a ring that may contain any of a nitrogen atom, a sulfur atom, and an oxygen atom, and the ring may be further substituted with a substituent. .

  The ring A represents a ring structure that may contain any of a nitrogen atom, a sulfur atom, and an oxygen atom, and preferred examples include a 5-membered ring and a 6-membered ring. The ring may be substituted with a substituent.

XY represents a bidentate ligand, and a bidentate monoanionic ligand is preferably exemplified.
Examples of the bidentate monoanionic ligand include picolinate (pic), acetylacetonate (acac), dipivaloylmethanate (t-butyl acac), and the like.
Examples of the ligand other than the above include the ligands described in pages 89 to 91 of International Publication No. 2002/15645 of Lamansky et al.

The substituent for R ¹¹ and R ¹² is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a halogen atom, an alkoxy group, an amino group, an alkyl group, a cycloalkyl group, a nitrogen atom or sulfur It represents an aryl group which may contain an atom, an aryloxy group which may contain a nitrogen atom or a sulfur atom, and these may be further substituted.
R ¹¹ and R ¹² may be bonded to each other adjacent to each other to form a ring that may contain a nitrogen atom, a sulfur atom, or an oxygen atom, and a 5-membered ring, a 6-membered ring, and the like are preferable. It is mentioned in. The ring may be further substituted with a substituent.

Specific examples of the compound represented by any one of the general formulas (2), (3), and (4) include, but are not limited to, the following compounds.

Other examples of the phosphorescent material include the following compounds.

The content of the red phosphorescent light emitting material is preferably 0.5% by mass to 30% by mass, more preferably 0.5% by mass to 20% by mass with respect to the total mass of the compound forming the light emitting layer. 3 mass%-10 mass% are still more preferable.
When the content is less than 0.5% by mass, the light emission efficiency may be reduced, and when it exceeds 30% by mass, the light emission efficiency may be reduced due to association of the phosphorescent material itself.

-Host material-
As the host material, a compound composed of at least one of a compound having an anthracene derivative skeleton and a compound having a pyrene derivative skeleton is used.

Examples of the compound having an anthracene derivative skeleton include an anthracene derivative represented by the following general formula (I).
However, in the general formula (I), Ar ¹ and Ar ² are each independently a group derived from a substituted or unsubstituted aromatic ring having 6 to 20 nuclear carbon atoms. The aromatic ring may be substituted with one or more substituents. The substituent is a substituted or unsubstituted aryl group having 6 to 50 nuclear carbon atoms, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 50 carbon atoms, a substituted group. Or an unsubstituted alkoxy group having 1 to 50 carbon atoms, a substituted or unsubstituted aralkyl group having 6 to 50 nuclear carbon atoms, a substituted or unsubstituted aryloxy group having 5 to 50 nuclear atoms, a substituted or unsubstituted nucleus. It is selected from an arylthio group having 5 to 50 atoms, a substituted or unsubstituted alkoxycarbonyl group having 1 to 50 carbon atoms, a substituted or unsubstituted silyl group, a carboxyl group, a halogen atom, a cyano group, a nitro group, and a hydroxy group. When the aromatic ring is substituted with two or more substituents, the substituents may be the same or different, and adjacent substituents are bonded to each other to form a saturated or unsaturated cyclic structure. May be formed.
R ¹ to R ⁸ are each a hydrogen atom, a substituted or unsubstituted aryl group having 6 to 50 nuclear carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 50 nuclear atoms, a substituted or unsubstituted carbon atom having 1 to 50 alkyl groups, substituted or unsubstituted cycloalkyl groups having 3 to 50 carbon atoms, substituted or unsubstituted alkoxy groups having 1 to 50 carbon atoms, substituted or unsubstituted aralkyl groups having 6 to 50 carbon atoms, substituted or Unsubstituted aryloxy group having 5 to 50 nuclear atoms, substituted or unsubstituted arylthio group having 5 to 50 nuclear atoms, substituted or unsubstituted alkoxycarbonyl group having 1 to 50 carbon atoms, substituted or unsubstituted silyl group Group, carboxyl group, halogen atom, cyano group, nitro group and hydroxy group. Further, adjacent substituents may be bonded to each other to form a saturated or unsaturated cyclic structure.

Specific examples of such anthracene derivatives include compounds represented by the following formulas.

  The anthracene derivative represented by the general formula (I) may be, for example, an asymmetric anthracene represented by the following general formula (3).

However, in the general formula (3), A ¹ and A ² are each independently a hydrogen atom or a substituted or unsubstituted aromatic ring group having 6 to 50 nuclear carbon atoms.
R ¹ to R ¹⁰ are each independently a hydrogen atom, a substituted or unsubstituted aromatic ring group having 6 to 50 nuclear carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 5 to 50 nuclear carbon atoms, substituted Or an unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkoxy group having 1 to 50 carbon atoms, a substituted or unsubstituted aralkyl group having 6 to 50 carbon atoms, Substituted or unsubstituted aryloxy group having 5 to 50 nucleus atoms, substituted or unsubstituted arylthio group having 5 to 50 nucleus atoms, substituted or unsubstituted alkoxycarbonyl group having 1 to 50 carbon atoms, substituted or unsubstituted Selected from silyl group, carboxyl group, halogen atom, cyano group, nitro group and hydroxyl group.
Ar ¹ , Ar ² , R ⁹ and R ¹⁰ may each be plural, and adjacent ones may form a saturated or unsaturated cyclic structure.
However, in the general formula (3), groups that are symmetrical with respect to the XY axis shown on the anthracene do not bind to the 9th and 10th positions of the central anthracene.

Examples of such an asymmetric anthracene derivative include the following.

The anthracene derivative represented by the general formula (I) may be a bisanthracene derivative represented by the following general formula (4).
However, in the general formula (4), Ant is an anthracene derivative and may be substituted. R represents a hydrogen atom, a substituted or unsubstituted aryl group having 6 to 50 nuclear carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 50 nuclear atoms, or a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms. Substituted or unsubstituted cycloalkyl group having 3 to 50 carbon atoms, substituted or unsubstituted alkoxy group having 1 to 50 carbon atoms, substituted or unsubstituted aralkyl group having 6 to 50 carbon atoms, substituted or unsubstituted nucleus Aryloxy group having 5 to 50 atoms, substituted or unsubstituted arylthio group having 5 to 50 nuclear atoms, substituted or unsubstituted alkoxycarbonyl group having 1 to 50 carbon atoms, substituted or unsubstituted silyl group, carboxyl group , A halogen atom, a cyano group, a nitro group and a hydroxy group. Further, adjacent substituents may be bonded to each other to form a saturated or unsaturated cyclic structure. K is an integer from 0 to 9.

Examples of such bisanthracene derivatives include the following formulas.

Further, the anthracene derivative represented by the general formula (I) may be a benzanthracene derivative represented by the following general formula (5).
However, in the general formula (5), A ¹ and A ² are each independently a substituted or unsubstituted aromatic ring group having 6 to 50 nuclear carbon atoms.
R ¹ to R ¹² are each independently a hydrogen atom, a substituted or unsubstituted aromatic ring group having 6 to 50 nuclear carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 5 to 50 nuclear carbon atoms, substituted Or an unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkoxy group having 1 to 50 carbon atoms, a substituted or unsubstituted aralkyl group having 6 to 50 carbon atoms, Substituted or unsubstituted aryloxy group having 5 to 50 nucleus atoms, substituted or unsubstituted arylthio group having 5 to 50 nucleus atoms, substituted or unsubstituted alkoxycarbonyl group having 1 to 50 carbon atoms, substituted or unsubstituted Selected from silyl group, carboxyl group, halogen atom, cyano group, nitro group and hydroxyl group.
Ar ¹ , Ar ² , R ^11, and R ¹² may each be plural, and adjacent ones may form a saturated or unsaturated cyclic structure.

The compound having an anthracene derivative skeleton in the light-emitting layer is particularly preferably a compound having an unsubstituted (no substituent) anthracene derivative skeleton from the viewpoint of suppressing a change in chromaticity before and after deterioration.
The compound having an anthracene derivative skeleton in the light-emitting layer is preferably non-nitrogen-containing, and it is particularly preferable that it does not have a lone electron pair from the viewpoint of suppressing chromaticity change before and after deterioration.

Examples of the compound having a pyrene derivative skeleton include pyrene derivatives represented by the following general formula (II).
However, in the general formula (II), Ar ^1a and Ar ^2a each represent a substituted or unsubstituted aromatic ring group having 6 to 50 nuclear carbon atoms.
L is a substituted or unsubstituted phenylene group, a substituted or unsubstituted naphthalenylene group, a substituted or unsubstituted fluorenylene group, or a substituted or unsubstituted dibenzosilolylene group, respectively.
m is an integer of 0 to 2, nb is an integer of 1 to 4, s is an integer of 0 to 2, and t is an integer of 0 to 4.
L or Ar ^1a is bonded to any one of positions 1 to 5 of pyrene, and L or Ar ^2a is bonded to any of positions 6 to 10 of pyrene.
However, when nb + t is an even number, Ar ^1a , Ar ^2a , and L satisfy the following (1) or (2).
(1) Ar ^1a ≠ Ar ^2a (where ≠ indicates a group having a different structure)
(2) When Ar ^1a = Ar ^2a (2-1) When m ≠ s and / or nb ≠ t, or (2-2) When m = s and nb = t,
(2-2-1) L or pyrene are bonded to different bonding positions on Ar ^1a and Ar ^2a , respectively.
(2-2-2) L, or pyrene, ^{Ar 1a} and when attached to the same bonding position on ^{Ar 2a,} L, or a substituted position in the pyrene ^{Ar 1a} and ^{Ar 2a} is 1-position and 6-position, Or it is not the 2nd and 7th positions.

Examples of such pyrene derivative compounds include the following.

The compound having a pyrene derivative skeleton in the light-emitting layer is particularly preferably a compound having an unsubstituted (no substituent) pyrene derivative skeleton from the viewpoint of suppressing a change in chromaticity before and after deterioration.
As the compound having a pyrene derivative skeleton in the light emitting layer, it is particularly preferable not to have a lone electron pair from the viewpoint of suppressing a change in chromaticity before and after deterioration.

  The content of the host material is preferably 10% by mass to 99.9% by mass, more preferably 20% by mass to 99.5% by mass with respect to the total mass of the compound forming the light emitting layer, and 30 A mass% to 99 mass% is more preferable.

The light-emitting layer receives holes from an anode, a hole injection layer, or a hole transport layer when an electric field is applied, receives electrons from a cathode, an electron injection layer, or an electron transport layer, and recombines holes and electrons. It is a layer having a function of providing a field to emit light.
The light emitting layer is not particularly limited and can be formed according to a known method. For example, by a dry film forming method such as a vapor deposition method or a sputtering method, a wet coating method, a transfer method, a printing method, an ink jet method, or the like. It can form suitably.

  There is no restriction | limiting in particular in the thickness of the said light emitting layer, According to the objective, it can select suitably, 2 nm-500 nm are preferable, 3 nm-200 nm are more preferable from a viewpoint of luminous efficiency, and 10 nm-200 nm are still more preferable. The light emitting layer may be a single layer or two or more layers.

<Cathode side adjacent layer>
The cathode side adjacent layer is an organic layer adjacent to the light emitting layer on the cathode side.
The cathode-side adjacent layer preferably contains at least one of a compound having a non-nitrogen-containing anthracene derivative skeleton and a compound having a pyrene derivative skeleton.
As the pyrene derivative skeleton, a compound having a pyrene derivative skeleton represented by the general formula (II) of the host material in the light emitting layer can be used.
As the compound having a non-nitrogen-containing anthracene derivative skeleton, a non-nitrogen-containing compound among the compounds represented by the general formula (I) of the host material in the light emitting layer can be used.
The compound having a non-nitrogen-containing anthracene derivative skeleton and the compound having the pyrene derivative skeleton in the cathode side adjacent layer are compounds having an unsubstituted (no substituent) anthracene derivative skeleton. This is particularly preferable in terms of suppressing the degree change.
It is particularly preferable that the compound having a non-nitrogen-containing anthracene derivative skeleton and the compound having a pyrene derivative skeleton in the cathode side adjacent layer have no lone pair of electrons from the viewpoint of suppressing chromaticity change before and after deterioration.

Here, although the specific example of the compound which has a pyrene derivative frame | skeleton suitably used for the said cathode side adjacent layer is given below, this invention is not limited to these compounds.

Specific examples of the compound having a non-nitrogen-containing anthracene derivative skeleton suitably used for the cathode-side adjacent layer will be described below, but the present invention is not limited to these compounds.

The cathode side adjacent layer is not particularly limited and can be formed according to a known method, for example, a dry film forming method such as a vapor deposition method and a sputtering method, a wet coating method, a transfer method, a printing method, an ink jet method, It can form suitably by.
The thickness of the cathode side adjacent layer is preferably 1 nm to 10 nm, and more preferably 2 nm to 5 nm. If the thickness is less than 1 nm, the cathode-side adjacent layer cannot be formed, and the effect of increasing efficiency and durability may not be sufficient. If the thickness exceeds 10 nm, the electron mobility of the cathode-side adjacent layer may be insufficient. Is high, the organic electroluminescent element may be increased in voltage.

<Electron transport layer>
The electron transport layer is a layer having a function of receiving electrons from the cathode or the cathode side and transporting them to the anode side.

  The material for the electron transport layer is not particularly limited and may be appropriately selected depending on the intended purpose. For example, 2,9-dimethyl-4,7-diphenyl-1,10- represented by the following structural formula is used. Phenanthroline (basocuproin; BCP), a BCP doped with Li, an organometallic complex having 8-quinolinol or a derivative thereof such as tris (8-quinolinolato) aluminum (Alq) represented by the following structural formula as a ligand, Quinoline derivatives, oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, such as BAlq (Bis- (2-methyl-8-quinolinolato) -4- (phenyl-phenolate) -aluminum (III)) represented by the following structural formula, Perylene derivatives, pyridine derivatives, pyrimidine derivatives, Nokisarin derivatives, diphenyl quinone derivative, a nitro-substituted fluorene derivatives, and the like.

The electron transport layer may be formed by, for example, vapor deposition, wet film formation, electron beam method, sputtering method, reactive sputtering method, MBE (molecular beam epitaxy) method, cluster ion beam method, ion plating method, plasma polymerization method ( (High-frequency excited ion plating method), molecular lamination method, LB method, printing method, transfer method, etc.
There is no restriction | limiting in particular as thickness of the said electron carrying layer, According to the objective, it can select suitably, For example, 1 nm-500 nm are preferable, and 10 nm-50 nm are more preferable.
The electron transport layer may have a single layer structure or a laminated structure.

The organic electroluminescent element of the present invention comprises an organic layer comprising at least one light emitting layer and at least a cathode side adjacent layer adjacent to the cathode side of the light emitting layer between the anode and the cathode, It may have an electron transport layer adjacent to the cathode side of the cathode side adjacent layer and, if necessary, other layers.
There is no restriction | limiting in particular as said other layer, According to the objective, it can select suitably, For example, an electron injection layer, a positive hole injection layer, a positive hole transport layer, an electronic block layer, etc. are mentioned.

-Electron injection layer-
The electron injection layer is a layer having a function of receiving electrons from the cathode or the cathode side and transporting them to the anode side.
The electron injection layer may have a single layer structure made of one or more materials, or may have a multilayer structure made of a plurality of layers having the same composition or different compositions.
There is no restriction | limiting in particular as thickness of the said electron injection layer, According to the objective, it can select suitably, It is preferable that it is 0.1 nm-200 nm, It is more preferable that it is 0.2 nm-100 nm. More preferably, it is 5 nm-50 nm.

-Hole injection layer, hole transport layer-
The hole injection layer and the hole transport layer are layers having a function of receiving holes from the anode or the anode side and transporting them to the cathode side. The hole injection layer and the hole transport layer may have a single layer structure or a multilayer structure composed of a plurality of layers having the same composition or different compositions.
The hole injection material or hole transport material used for these layers may be a low molecular compound, a high molecular compound, or an inorganic compound.
The hole injection material or hole transport material is not particularly limited and may be appropriately selected depending on the purpose. For example, a pyrrole derivative, a carbazole derivative, a triazole derivative, an oxazole derivative, an oxadiazole derivative, an imidazole derivative, Polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aromatic tertiary amine compounds, styrylamine Compounds, aromatic dimethylidin compounds, phthalocyanine compounds, porphyrin compounds, thiophene derivatives, organic silane derivatives, carbon, molybdenum trioxide, and the like. These may be used individually by 1 type and may use 2 or more types together.

The hole injection layer and the hole transport layer may contain an electron accepting dopant.
As the electron-accepting dopant, an inorganic compound or an organic compound can be used as long as it has an electron-accepting property and oxidizes an organic compound.
The inorganic compound is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include metal halides such as ferric chloride, aluminum chloride, gallium chloride, indium chloride, and antimony pentachloride; vanadium pentoxide, And metal oxides such as molybdenum trioxide.
The organic compound is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a compound having a nitro group, a halogen, a cyano group, a trifluoromethyl group or the like as a substituent; a quinone compound, an acid anhydride Compounds, fullerenes, and the like. These may be used individually by 1 type and may use 2 or more types together.
The amount of the electron-accepting dopant used is not particularly limited and varies depending on the type of material, but is preferably 0.01% by mass to 50% by mass with respect to the hole transport layer material or the hole injection material, 0.05 The mass% to 30 mass% is more preferable, and 0.1 mass% to 30 mass% is still more preferable.

The hole injection layer and the hole transport layer are not particularly limited and can be formed according to a known method. For example, a dry film forming method such as a vapor deposition method and a sputtering method, a wet coating method, a transfer method, and a printing method. It can be suitably formed by a method, an ink jet method, or the like.
The thickness of the hole injection layer and the hole transport layer is preferably 1 nm to 500 nm, more preferably 5 nm to 250 nm, and still more preferably 10 nm to 200 nm.

-Electronic block layer-
The electron blocking layer is a layer having a function of preventing electrons transported from the cathode side to the light emitting layer from passing through to the anode side, and is usually provided as an organic compound layer adjacent to the light emitting layer on the anode side.
As a compound which comprises the said electronic block layer, what was mentioned, for example as the above-mentioned hole transport material can be utilized. In addition, the electron blocking layer may have a single layer structure made of one or more of the materials described above, or may have a multilayer structure made of a plurality of layers having the same composition or different compositions.
The electron blocking layer is not particularly limited and can be formed according to a known method. For example, a dry film forming method such as a vapor deposition method or a sputtering method, a wet coating method, a transfer method, a printing method, an ink jet method, etc. It can form more suitably.
The thickness of the electron blocking layer is preferably 1 nm to 200 nm, more preferably 1 nm to 50 nm, and still more preferably 3 nm to 10 nm.

<Electrode>
The organic electroluminescent element of the present invention includes a pair of electrodes, that is, an anode and a cathode. In view of the nature of the organic electroluminescence device, at least one of the anode and the cathode is preferably transparent. Usually, the anode only needs to have a function as an electrode for supplying holes to the organic compound layer, and the cathode only needs to have a function as an electrode for injecting electrons into the organic compound layer.
There is no restriction | limiting in particular about the shape, a structure, a magnitude | size, etc. as said electrode, According to the use and objective of an organic electroluminescent element, it can select suitably from well-known electrode materials.
As a material which comprises the said electrode, a metal, an alloy, a metal oxide, a conductive compound, or a mixture thereof etc. are mentioned suitably, for example.

-Anode-
Examples of the material constituting the anode include tin oxide doped with antimony and fluorine (ATO, FTO), tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO). Conductive metal oxides; metals such as gold, silver, chromium and nickel; mixtures or laminates of these metals and conductive metal oxides; inorganic conductive materials such as copper iodide and copper sulfide; polyaniline, polythiophene, Examples thereof include organic conductive materials such as polypyrrole, and laminates of these with ITO. Among these, a conductive metal oxide is preferable, and ITO is particularly preferable in terms of productivity, high conductivity, transparency, and the like.

-Cathode-
Examples of the material constituting the cathode include alkali metals (eg, Li, Na, K, Cs, etc.), alkaline earth metals (eg, Mg, Ca, etc.), gold, silver, lead, aluminum, sodium-potassium alloys, Examples thereof include lithium-aluminum alloys, magnesium-silver alloys, rare earth metals such as indium and ytterbium. These may be used alone, but two or more can be suitably used in combination from the viewpoint of achieving both stability and electron injection.
Among these, alkali metals and alkaline earth metals are preferable from the viewpoint of electron injecting properties, and materials mainly composed of aluminum are particularly preferable from the viewpoint of excellent storage stability.
The material mainly composed of aluminum is aluminum alone, an alloy of aluminum and 0.01% by mass to 10% by mass of alkali metal or alkaline earth metal, or a mixture thereof (for example, lithium-aluminum alloy, magnesium-aluminum). Alloy).

  The method for forming the electrode is not particularly limited and can be performed according to a known method. For example, a wet method such as a printing method or a coating method; a physical method such as a vacuum deposition method, a sputtering method, or an ion plating method; Chemical methods such as CVD and plasma CVD may be used. Among these, it can be formed on the substrate according to a method selected appropriately in consideration of suitability with the material constituting the electrode. For example, when ITO is selected as the anode material, it can be formed according to a direct current or high frequency sputtering method, a vacuum deposition method, an ion plating method, or the like. When a metal or the like is selected as the cathode material, one or more of them can be formed simultaneously or sequentially according to a sputtering method or the like.

  In addition, when patterning is performed when forming the electrode, it may be performed by chemical etching such as photolithography, or may be performed by physical etching using a laser or the like. It may be performed by sputtering or the like, or may be performed by a lift-off method or a printing method.

<Board>
The organic electroluminescent element of the present invention is preferably provided on a substrate, and may be provided in such a manner that the electrode and the substrate are in direct contact with each other, or may be provided in an intermediate layer. .
The material for the substrate is not particularly limited and may be appropriately selected depending on the intended purpose. For example, inorganic materials such as yttria-stabilized zirconia (YSZ) and glass (such as alkali-free glass and soda lime glass); polyethylene terephthalate And polyesters such as polybutylene phthalate and polyethylene naphthalate; organic materials such as polystyrene, polycarbonate, polyethersulfone, polyarylate, polyimide, polycycloolefin, norbornene resin, and poly (chlorotrifluoroethylene).

  There is no restriction | limiting in particular about the shape of the said board | substrate, a structure, a magnitude | size, It can select suitably according to the use, purpose, etc. of a light emitting element. In general, the shape of the substrate is preferably a plate shape. The structure of the substrate may be a single layer structure, a laminated structure, may be formed of a single member, or may be formed of two or more members. The substrate may be transparent or opaque, and if transparent, it may be colorless and transparent or colored and transparent.

The substrate may be provided with a moisture permeation preventing layer (gas barrier layer) on the front surface or the back surface.
Examples of the material of the moisture permeation preventive layer (gas barrier layer) include inorganic substances such as silicon nitride and silicon oxide.
The moisture permeation preventing layer (gas barrier layer) can be formed by, for example, a high frequency sputtering method.

-Protective layer-
The entire organic electroluminescent element may be protected by a protective layer.
The material contained in the protective layer is not particularly limited as long as it has a function of suppressing the entry of elements that promote element deterioration such as moisture and oxygen into the element. For example, metals such as In, Sn, Pb, Au, Cu, Ag, Al, Ti, Ni; MgO, SiO, SiO ₂ , Al ₂ O ₃ , GeO, NiO, CaO, BaO, Fe ₂ Metal oxides such as O ₃ , Y ₂ O ₃ and TiO ₂ ; Metal nitrides such as SiNx and SiNxOy; Metal fluorides such as MgF ₂ , LiF, AlF ₃ and CaF ₂ ; Polyethylene, polypropylene, polymethyl methacrylate, polyimide , Polyurea, polytetrafluoroethylene, polychlorotrifluoroethylene, polydichlorodifluoroethylene, chlorotrifluoroethylene A copolymer of dichlorodifluoroethylene, a copolymer obtained by copolymerizing a monomer mixture containing tetrafluoroethylene and at least one comonomer, a fluorinated copolymer having a cyclic structure in the copolymer main chain, water absorption Examples thereof include a water-absorbing substance having a rate of 1% or more, a moisture-proof substance having a water absorption rate of 0.1% or less, and the like.

  There is no restriction | limiting in particular as a formation method of the said protective layer, According to the objective, it can select suitably, For example, a vacuum evaporation method, sputtering method, reactive sputtering method, MBE (molecular beam epitaxy) method, cluster ion beam method , Ion plating method, plasma polymerization method (high frequency excitation ion plating method), plasma CVD method, laser CVD method, thermal CVD method, gas source CVD method, coating method, printing method, transfer method and the like.

-Sealing container-
As for the organic electroluminescent element of this invention, the whole element may be sealed using the sealing container. Furthermore, a moisture absorbent or an inert liquid may be sealed in the space between the sealing container and the organic electroluminescent element.
The moisture absorbent is not particularly limited and may be appropriately selected depending on the intended purpose. For example, barium oxide, sodium oxide, potassium oxide, calcium oxide, sodium sulfate, calcium sulfate, magnesium sulfate, phosphorus pentoxide, chloride Calcium, magnesium chloride, copper chloride, cesium fluoride, niobium fluoride, calcium bromide, vanadium bromide, molecular sieve, zeolite, magnesium oxide, and the like can be given.
The inert liquid is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include paraffins, liquid paraffins; fluorinated solvents such as perfluoroalkane, perfluoroamine, and perfluoroether; Examples include solvents and silicone oils.

-Resin sealing layer-
The organic electroluminescent device of the present invention is preferably suppressed by sealing the device performance deterioration due to oxygen and moisture from the atmosphere with a resin sealing layer.
The resin material for the resin sealing layer is not particularly limited and can be appropriately selected depending on the purpose. For example, acrylic resin, epoxy resin, fluorine resin, silicone resin, rubber resin, ester resin, Etc. Among these, an epoxy resin is particularly preferable from the viewpoint of moisture prevention function. Among the epoxy resins, a thermosetting epoxy resin or a photocurable epoxy resin is preferable.

  There is no restriction | limiting in particular as a preparation method of the said resin sealing layer, According to the objective, it can select suitably, For example, the method of apply | coating a resin solution, the method of crimping | bonding or thermocompressing a resin sheet, vapor deposition, sputtering, etc. And a dry polymerization method.

-Sealing adhesive-
The sealing adhesive has a function of preventing intrusion of moisture and oxygen from the end portion.
As the material of the sealing adhesive, the same material as that used for the resin sealing layer can be used. Among these, an epoxy adhesive is preferable from the viewpoint of preventing moisture from entering, and a photocurable adhesive or a thermosetting adhesive is particularly preferable.
It is also preferable to add a filler to the sealing adhesive. As the filler, for example _SiO 2, SiO (silicon oxide), SiON (silicon oxynitride), an inorganic material such as SiN (silicon nitride) are preferred. Addition of the filler increases the viscosity of the sealing adhesive, improves processing suitability, and improves moisture resistance.
The sealing adhesive may contain a desiccant. Examples of the desiccant include barium oxide, calcium oxide, and strontium oxide. The addition amount of the desiccant is preferably 0.01% by mass to 20% by mass and more preferably 0.05% by mass to 15% by mass with respect to the sealing adhesive. When the addition amount is less than 0.01% by mass, the effect of adding the desiccant is diminished, and when it exceeds 20% by mass, it is difficult to uniformly disperse the desiccant in the sealing adhesive. Sometimes.
In the present invention, the sealing adhesive containing the desiccant can be applied by applying an arbitrary amount with a dispenser or the like, and the second substrate can be overlaid after application and cured.

  FIG. 1 is a schematic view showing an example of the layer structure of the organic electroluminescent element of the present invention. The organic EL element 11 includes an anode 2 (for example, an ITO electrode) formed on the glass substrate 1, a hole injection layer 3, a hole transport layer 4, an electron blocking layer 5, a light emitting layer 6, and a cathode side. It has a layer structure in which an adjacent layer (hole blocking layer) 7, an electron transport layer 8, an electron injection layer 9, and a cathode 10 (for example, an Al—Li electrode) are laminated in this order. The anode 2 (for example, ITO electrode) and the cathode 10 (for example, Al—Li electrode) are connected to each other via a power source.

-Drive-
The organic electroluminescence device of the present invention emits light by applying a direct current (which may include an alternating current component as necessary) voltage (usually 2 to 15 volts) or a direct current between the anode and the cathode. Obtainable.
The organic electroluminescent element of the present invention can be applied to an active matrix by a thin film transistor (TFT). As the active layer of the thin film transistor, amorphous silicon, high temperature polysilicon, low temperature polysilicon, microcrystalline silicon, oxide semiconductor, organic semiconductor, carbon nanotube, or the like can be used.
For example, the thin film transistors described in WO2005 / 088826, JP-A-2006-165529, US Patent Application Publication No. 2008 / 0237598A1, and the like can be applied to the organic electroluminescent device of the present invention.

There is no restriction | limiting in particular in the organic electroluminescent element of this invention, Light extraction efficiency can be improved by various well-known devices. For example, by processing the substrate surface shape (for example, forming a fine concavo-convex pattern), controlling the refractive index of the substrate, ITO layer, organic layer, controlling the thickness of the substrate, ITO layer, organic layer, etc. It is possible to improve the external quantum efficiency.
The light extraction method from the organic electroluminescence device of the present invention may be a top emission method or a bottom emission method.

The organic electroluminescent element of the present invention may have a resonator structure. For example, a multilayer mirror made of a plurality of laminated films having different refractive indexes, a transparent or translucent electrode, a light emitting layer, and a metal electrode are superimposed on a transparent substrate. The light generated in the light emitting layer resonates repeatedly with the multilayer mirror and the metal electrode as a reflection plate.
In another preferred embodiment, a transparent or translucent electrode and a metal electrode each function as a reflecting plate on a transparent substrate, and light generated in the light emitting layer repeats reflection and resonates between them.
In order to form a resonant structure, the optical path length determined from the effective refractive index of the two reflectors and the refractive index and thickness of each layer between the reflectors is adjusted to an optimum value to obtain the desired resonant wavelength. Is done. The calculation formula in the case of the first aspect is described in JP-A-9-180883. The calculation formula in the case of the second aspect is described in Japanese Patent Application Laid-Open No. 2004-127795.

-Use-
The organic electroluminescent element of the present invention is not particularly limited and may be appropriately selected depending on the intended purpose. However, the display element, display, backlight, electrophotography, illumination light source, recording light source, exposure light source, reading light source, label It can be suitably used for signboards, interiors, optical communications, and the like.
As a method for making the organic EL display of a full color type, as described in, for example, “Monthly Display”, September 2000, pages 33 to 37, the three primary colors (blue (B), green (G), red light (R)), a three-color light emitting method in which organic EL elements that respectively emit light corresponding to red (R) are arranged on a substrate, and white light emission by an organic electroluminescent element for white light emission is divided into three primary colors through a color filter. A white method, a color conversion method for converting blue light emission by a blue light emitting organic electroluminescent element into red (R) and green (G) through a dye layer, and the like are known. Moreover, the planar light source of a desired luminescent color can be obtained by using combining the organic electroluminescent element of the different luminescent color obtained by the said method. For example, a white light-emitting light source combining blue and yellow light-emitting elements, a white light-emitting light source combining blue, green, and red light-emitting elements can be used.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Comparative Example 1-1)
-Fabrication of organic electroluminescence device-
ITO (Indium Tin Oxide) having a thickness of 70 nm was formed as a positive electrode on a 0.5 mm thick, 2.5 cm square glass substrate by sputtering. Next, this ITO-attached glass substrate was put into a cleaning container, subjected to ultrasonic cleaning in 2-propanol, and then subjected to UV-ozone treatment for 30 minutes.
In addition, the vapor deposition rate in the following examples and comparative examples is 0.1 nm / second unless otherwise specified. The deposition rate was measured using a quartz resonator. The thickness of each layer below was measured using a quartz resonator.

First, NPD (N, N′-dinaphthyl-N, N′-diphenyl- [1,1′-biphenyl] -4,4′-diamine) represented by the following structural formula is formed on the anode (ITO). A hole injection layer doped with 30% by mass of MoO ₃ was formed by vacuum deposition so that the thickness was 30 nm.

Next, an NPD (N, N′-dinaphthyl-N, N′-diphenyl- [1,1′-biphenyl] -4,4 represented by the above structural formula as a hole transport layer is formed on the hole injection layer. '-Diamine) was formed by vacuum deposition so that the thickness was 10 nm.
Next, a compound J represented by the following structural formula, which is a host material, and a light emitting layer doped with 8% by mass of the red phosphorescent light emitting material 1 (peak wavelength 628 nm) represented by the following structural formula with respect to the compound J It formed by the vacuum evaporation method so that thickness might be set to 30 nm.

Next, a compound F represented by the following structural formula was formed as a cathode side adjacent layer on the light emitting layer by a vacuum deposition method so as to have a thickness of 5 nm.

Next, a compound F represented by the above structural formula was formed as an electron transport layer on the cathode side adjacent layer by a vacuum deposition method so as to have a thickness of 45 nm.
Next, lithium fluoride (LiF) was formed as an electron injection layer on the electron transport layer by a vacuum deposition method so as to have a thickness of 1 nm.
Next, a patterned mask (mask with a light emitting area of 2 mm × 2 mm) was placed on the electron injection layer as a cathode, and metal aluminum was formed by vacuum deposition so as to have a thickness of 100 nm.
The laminate produced as described above was put in a glove box substituted with argon gas, and sealed with a stainless steel sealing can and an ultraviolet curable adhesive (XNR5516HV, manufactured by Nagase Ciba Co., Ltd.). The organic electroluminescent element of Comparative Example 1-1 was produced as described above.

(Comparative Example 1-2)
-Fabrication of organic electroluminescence device-
In Comparative Example 1-1, except that Compound F represented by the above structural formula as the cathode-side adjacent layer was replaced with Compound 2a-1 represented by the following structural formula, the same as Comparative Example 1-1 The organic electroluminescent element of Comparative Example 1-2 was produced.

(Comparative Example 1-3)
-Fabrication of organic electroluminescence device-
In Comparative Example 1-1, except that Compound J represented by the above structural formula as the host material of the light-emitting layer was replaced with Compound 2a-1 represented by the above structural formula, the same as Comparative Example 1-1 The organic electroluminescent element of Comparative Example 1-3 was produced.

(Example 1-1)
-Fabrication of organic electroluminescence device-
In Comparative Example 1-1, the compound J represented by the above structural formula as the host material of the light emitting layer is replaced by the compound 2a-1 represented by the above structural formula, and represented by the above structural formula as the cathode side adjacent layer. The organic electroluminescent element of Example 1-1 was produced in the same manner as Comparative Example 1-1 except that Compound F was changed to Compound 2a-1 represented by the above structural formula.

(Comparative Example 2-1)
-Fabrication of organic electroluminescence device-
In Comparative Example 1-1, a comparison was made in the same manner as in Comparative Example 1-1 except that Compound J represented by the above structural formula as the host material of the light emitting layer was replaced with Compound K represented by the following structural formula. The organic electroluminescent element of Example 2-1 was produced.

(Comparative Example 2-2)
-Fabrication of organic electroluminescence device-
In Comparative Example 1-1, the compound J represented by the above structural formula as the host material of the light emitting layer is replaced with the compound K represented by the above structural formula, and the compound represented by the above structural formula as the cathode side adjacent layer An organic electroluminescent element of Comparative Example 2-2 was produced in the same manner as Comparative Example 1-1 except that F was replaced with Compound 2a′-55 represented by the following structural formula.

(Comparative Example 2-3)
-Fabrication of organic electroluminescence device-
In Comparative Example 1-1, the procedure was the same as Comparative Example 1-1 except that Compound J represented by the structural formula as a host material for the light-emitting layer was replaced with Compound 2a′-55 represented by the structural formula. Thus, an organic electroluminescent element of Comparative Example 2-3 was produced.

(Example 2-1)
-Fabrication of organic electroluminescence device-
In Comparative Example 1-1, the compound J represented by the above structural formula as the host material of the light emitting layer was replaced with the compound 2a′-55 represented by the above structural formula, and represented by the above structural formula as the cathode side adjacent layer. The organic electroluminescent element of Example 2-1 was produced in the same manner as in Comparative Example 1-1 except that the compound F to be used was changed to the compound 2a′-55 represented by the above structural formula.

(Comparative Example 3-1)
-Fabrication of organic electroluminescence device-
In Comparative Example 1-1, the compound J represented by the above structural formula as the host material of the light-emitting layer was replaced with mCP (N, N′-dicarbazolyl-3,5-benzene) represented by the following structural formula. The organic electroluminescence of Comparative Example 3-1 was the same as Comparative Example 1-1 except that Compound F represented by the structural formula described above as the side adjacent layer was replaced with Compound I represented by the following structural formula. An element was produced.

(Comparative Example 3-2)
-Fabrication of organic electroluminescence device-
In Comparative Example 1-1, the compound J represented by the above structural formula as the host material of the light-emitting layer was replaced with mCP (N, N′-dicarbazolyl-3,5-benzene) represented by the above structural formula. Comparative Example 3-2 was carried out in the same manner as in Comparative Example 1-1 except that Compound F represented by the above structural formula as the side adjacent layer was replaced with Compound 2a′-59 represented by the following structural formula. An organic electroluminescent element was produced.

(Comparative Example 3-3)
-Fabrication of organic electroluminescence device-
In Comparative Example 1-1, the compound J represented by the above structural formula as the host material of the light emitting layer was replaced with the compound 2a′-59 represented by the above structural formula, and represented by the above structural formula as the cathode side adjacent layer. The organic electroluminescent element of Comparative Example 3-3 was produced in the same manner as Comparative Example 1-1 except that Compound F was replaced with Compound I represented by the above structural formula.

(Example 3-1)
-Fabrication of organic electroluminescence device-
In Comparative Example 1-1, the compound J represented by the above structural formula as the host material of the light emitting layer was replaced with the compound 2a′-59 represented by the above structural formula, and represented by the above structural formula as the cathode side adjacent layer. The organic electroluminescent element of Example 3-1 was produced in the same manner as Comparative Example 1-1 except that the compound F to be used was changed to the compound 2a′-59 represented by the above structural formula.

(Comparative Example 4-1)
In Comparative Example 1-1, the compound J represented by the above structural formula as the host material of the light-emitting layer was replaced with mCP (N, N′-dicarbazolyl-3,5-benzene) represented by the above structural formula. Organic electroluminescence of Comparative Example 4-1 is the same as Comparative Example 1-1 except that Compound F represented by the structural formula as a side adjacent layer is replaced with Compound I represented by the structural formula. An element was produced.

(Comparative Example 4-2)
In Comparative Example 1-1, the compound J represented by the above structural formula as the host material of the light-emitting layer was replaced with mCP (N, N′-dicarbazolyl-3,5-benzene) represented by the above structural formula. Organic electroluminescence of Comparative Example 4-2 was performed in the same manner as Comparative Example 1-1 except that Compound F represented by the above structural formula as the side adjacent layer was replaced with Compound 3a represented by the following structural formula. An element was produced.

(Comparative Example 4-3)
In Comparative Example 1-1, the compound J represented by the structural formula described above as the host material of the light-emitting layer is replaced with the compound 3a represented by the structural formula described above, and the compound represented by the structural formula described above as the cathode side adjacent layer An organic electroluminescent element of Comparative Example 4-3 was produced in the same manner as Comparative Example 1-1 except that F was replaced with Compound I represented by the above structural formula.

( Reference Example 4-1)
In Comparative Example 1-1, the compound J represented by the structural formula described above as the host material of the light-emitting layer is replaced with the compound 3a represented by the structural formula described above, and the compound represented by the structural formula described above as the cathode side adjacent layer An organic electroluminescent element of Reference Example 4-1 was produced in the same manner as in Comparative Example 1-1 except that F was replaced with the compound 3a represented by the above structural formula.

(Comparative Example 5-1)
-Fabrication of organic electroluminescence device-
ITO (Indium Tin Oxide) having a thickness of 70 nm was formed as a positive electrode on a 0.5 mm thick, 2.5 cm square glass substrate by sputtering. Next, this ITO-attached glass substrate was put into a cleaning container, subjected to ultrasonic cleaning in 2-propanol, and then subjected to UV-ozone treatment for 30 minutes.
In addition, the vapor deposition rate in the following examples and comparative examples is 0.1 nm / second unless otherwise specified. The deposition rate was measured using a quartz resonator. The thickness of each layer below was measured using a quartz resonator.

First, NPD (N, N′-dinaphthyl-N, N′-diphenyl- [1,1′-biphenyl] -4,4′-diamine) represented by the following structural formula is formed on the anode (ITO). A hole injection layer doped with 30% by mass of MoO ₃ was formed by vacuum deposition so that the thickness was 30 nm.

Next, an NPD (N, N′-dinaphthyl-N, N′-diphenyl- [1,1′-biphenyl] -4,4 represented by the above structural formula as a hole transport layer is formed on the hole injection layer. '-Diamine) was formed by vacuum deposition so that the thickness was 10 nm.
Next, BAlq [Bis- (2-methyl-8-quinolinolato) -4- (phenyl-phenolate) -aluminum (III)] represented by the following structural formula, which is a host material, and the following structure with respect to the BAlq A light emitting layer doped with 8% by mass of the red phosphorescent light emitting material 2 represented by the formula (peak wavelength: 627 nm) was formed by a vacuum deposition method so as to have a thickness of 30 nm.

Next, an aluminum quinoline complex (Alq) represented by the following structural formula was formed as a cathode-side adjacent layer on the light-emitting layer by a vacuum deposition method so as to have a thickness of 5 nm.

Next, a compound G represented by the following structural formula was formed as an electron transport layer on the cathode side adjacent layer by a vacuum deposition method so as to have a thickness of 45 nm.

Next, lithium fluoride (LiF) was formed as an electron injection layer on the electron transport layer by a vacuum deposition method so as to have a thickness of 1 nm.
Next, a patterned mask (mask with a light emitting area of 2 mm × 2 mm) was placed on the electron injection layer as a cathode, and metal aluminum was formed by vacuum deposition so as to have a thickness of 100 nm.
The laminate produced as described above was put in a glove box substituted with argon gas, and sealed with a stainless steel sealing can and an ultraviolet curable adhesive (XNR5516HV, manufactured by Nagase Ciba Co., Ltd.). Thus, an organic electroluminescent element of Comparative Example 5-1 was produced.

(Comparative Example 5-2)
In Comparative Example 5-1, except that Alq represented by the above structural formula as the cathode-side adjacent layer was replaced with Compound 2a-1 represented by the following structural formula, An organic electroluminescent element of Comparative Example 5-2 was produced.

(Comparative Example 5-3)
In Comparative Example 5-1, the same procedure as in Comparative Example 5-1 was conducted, except that BAlq represented by the above structural formula as the host material of the light-emitting layer was replaced with compound 2a-1 represented by the above structural formula. The organic electroluminescent element of Comparative Example 5-3 was produced.

(Example 5-1)
In Comparative Example 5-1, BAlq represented by the above structural formula as the host material of the light emitting layer is replaced by the compound 2a-1 represented by the above structural formula, and represented by the above structural formula as the cathode side adjacent layer. The organic electroluminescent element of Example 5-1 was produced in the same manner as in Comparative Example 5-1, except that the aluminum quinoline complex (Alq) was replaced with the compound 2a-1 represented by the above structural formula.

(Comparative Example 6-1)
In Comparative Example 5-1, BAlq represented by the above structural formula as the host material of the light-emitting layer was replaced with 4,4′-bis (9-carbazolyl) -biphenyl (CBP) represented by the following structural formula. Except for the above, an organic electroluminescent element of Comparative Example 6-1 was produced in the same manner as Comparative Example 5-1.

(Comparative Example 6-2)
In Comparative Example 5-1, BAlq represented by the above structural formula as a host material of the light emitting layer was replaced with 4,4′-bis (9-carbazolyl) -biphenyl (CBP) represented by the above structural formula, Comparison was made in the same manner as in Comparative Example 5-1, except that the aluminum quinoline complex (Alq) represented by the above structural formula as the cathode side adjacent layer was replaced with the compound 2a′-55 represented by the following structural formula. The organic electroluminescent element of Example 6-2 was produced.

(Comparative Example 6-3)
In Comparative Example 5-1, the same procedure as in Comparative Example 5-1 was conducted, except that BAlq represented by the above structural formula as the host material of the light-emitting layer was replaced with compound 2a′-55 represented by the above structural formula. Thus, an organic electroluminescent element of Comparative Example 6-3 was produced.

(Example 6-1)
In Comparative Example 5-1, BAlq represented by the above structural formula as the host material of the light-emitting layer was replaced by Compound 2a′-55 represented by the above structural formula, and represented by the above structural formula as the cathode side adjacent layer. The organic electroluminescent element of Example 6-1 was prepared in the same manner as in Comparative Example 5-1, except that the aluminum quinoline complex (Alq) was changed to the compound 2a′-55 represented by the above structural formula. did.

(Comparative Example 7-1)
In Comparative Example 5-1, BAlq represented by the above structural formula as the host material of the light emitting layer was replaced with 4,4′-bis (9-carbazolyl) -biphenyl (CBP) represented by the above structural formula. Except that, an organic electroluminescent element of Comparative Example 7-1 was produced in the same manner as Comparative Example 5-1.

(Comparative Example 7-2)
In Comparative Example 5-1, BAlq represented by the above structural formula as a host material of the light emitting layer was replaced with 4,4′-bis (9-carbazolyl) -biphenyl (CBP) represented by the above structural formula, Comparison was made in the same manner as in Comparative Example 5-1, except that the aluminum quinoline complex (Alq) represented by the above structural formula as the cathode side adjacent layer was replaced with the compound 2a′-59 represented by the following structural formula. The organic electroluminescent element of Example 7-2 was produced.

(Comparative Example 7-3)
In Comparative Example 5-1, the same procedure as in Comparative Example 5-1 was conducted, except that BAlq represented by the structural formula as a host material of the light-emitting layer was replaced with compound 2a′-59 represented by the structural formula. The organic electroluminescent element of Comparative Example 7-3 was produced.

(Example 7-1)
In Comparative Example 5-1, BAlq represented by the above structural formula as the host material of the light-emitting layer is replaced by Compound 2a′-59 represented by the above structural formula, and represented by the above structural formula as the cathode side adjacent layer. The organic electroluminescent element of Example 7-1 was produced in the same manner as in Comparative Example 5-1, except that the aluminum quinoline complex (Alq) was replaced with the compound 2a′-59 represented by the above structural formula. did.

(Comparative Example 8-1)
In Comparative Example 5-1, BAlq represented by the above structural formula as the host material of the light emitting layer was replaced with 4,4′-bis (9-carbazolyl) -biphenyl (CBP) represented by the above structural formula. Except for the above, an organic electroluminescent element of Comparative Example 8-1 was produced in the same manner as Comparative Example 5-1.

(Comparative Example 8-2)
In Comparative Example 5-1, BAlq represented by the above structural formula as a host material of the light emitting layer was replaced with 4,4′-bis (9-carbazolyl) -biphenyl (CBP) represented by the above structural formula, Comparative Example 8- in the same manner as Comparative Example 5-1, except that the aluminum quinoline complex (Alq) represented by the above structural formula as the cathode-side adjacent layer was replaced with compound 3a represented by the following structural formula. 2 organic electroluminescent elements were produced.

(Comparative Example 8-3)
In Comparative Example 5-1, a comparison was made in the same manner as Comparative Example 5-1, except that BAlq represented by the above structural formula as the host material of the light-emitting layer was replaced with compound 3a represented by the above structural formula. The organic electroluminescent element of Example 8-3 was produced.

( Reference Example 8-1)
In Comparative Example 5-1, BAlq represented by the above structural formula as the host material of the light emitting layer is replaced with the compound 3a represented by the above structural formula, and aluminum represented by the above structural formula as the cathode side adjacent layer An organic electroluminescent element of Reference Example 8-1 was produced in the same manner as in Comparative Example 5-1, except that the quinoline complex (Alq) was replaced with the compound 3a represented by the above structural formula.

(Comparative Example 9-1)
In Comparative Example 5-1, BAlq represented by the above structural formula as the host material of the light emitting layer was replaced with 4,4′-bis (9-carbazolyl) -biphenyl (CBP) represented by the above structural formula. Except for the above, an organic electroluminescent element of Comparative Example 9-1 was produced in the same manner as Comparative Example 5-1.

(Comparative Example 9-2)
In Comparative Example 5-1, BAlq represented by the above structural formula as a host material of the light emitting layer was replaced with 4,4′-bis (9-carbazolyl) -biphenyl (CBP) represented by the above structural formula, Comparative Example 9- was performed in the same manner as Comparative Example 5-1, except that the aluminum quinoline complex (Alq) represented by the above structural formula as the cathode side adjacent layer was replaced with Compound A represented by the following structural formula. 2 organic electroluminescent elements were produced.

(Comparative Example 9-3)
In Comparative Example 5-1, a comparison was made in the same manner as in Comparative Example 5-1, except that BAlq represented by the above structural formula as the host material of the light emitting layer was replaced with Compound A represented by the above structural formula. The organic electroluminescent element of Example 9-3 was produced.

(Example 9-1)
In Comparative Example 5-1, BAlq represented by the above structural formula as the host material of the light-emitting layer is replaced with Compound A represented by the above structural formula, and aluminum represented by the above structural formula as the cathode side adjacent layer An organic electroluminescent element of Example 9-1 was produced in the same manner as in Comparative Example 5-1, except that the quinoline complex (Alq) was replaced with the compound A represented by the above structural formula.

(Comparative Example 10-1)
-Fabrication of organic electroluminescence device-
ITO (Indium Tin Oxide) having a thickness of 70 nm was formed as a positive electrode on a 0.5 mm thick, 2.5 cm square glass substrate by sputtering. Next, this ITO-attached glass substrate was put into a cleaning container, subjected to ultrasonic cleaning in 2-propanol, and then subjected to UV-ozone treatment for 30 minutes.
In addition, the vapor deposition rate in the following examples and comparative examples is 0.1 nm / second unless otherwise specified. The deposition rate was measured using a quartz resonator. The thickness of each layer below was measured using a quartz resonator.

First, on the anode (ITO), a hole injection layer in which 30% by mass of MoO ₃ was doped into the compound L represented by the following structural formula was formed by vacuum deposition so that the thickness was 30 nm.

Next, an NPD (N, N′-dinaphthyl-N, N′-diphenyl- [1,1′-biphenyl] -4,4 represented by the following structural formula as a hole transport layer is formed on the hole injection layer. '-Diamine) was formed by vacuum deposition so that the thickness was 10 nm.

Next, BAlq [Bis- (2-methyl-8-quinolinolato) -4- (phenyl-phenolate) -aluminum (III)] represented by the following structural formula, which is a host material, and the following structure with respect to the BAlq A light emitting layer doped with 8% by mass of the red phosphorescent light emitting material 3 represented by the formula (peak wavelength: 620 nm) was formed by vacuum deposition so as to have a thickness of 30 nm.

  Next, BAlq represented by the above structural formula as a cathode side adjacent layer was formed on the light emitting layer by a vacuum deposition method so as to have a thickness of 5 nm.

Next, Compound I represented by the following structural formula as an electron transport layer was formed on the cathode side adjacent layer by a vacuum deposition method so as to have a thickness of 45 nm.

Next, lithium fluoride (LiF) was formed as an electron injection layer on the electron transport layer by a vacuum deposition method so as to have a thickness of 1 nm.
Next, a mask patterned as a cathode (a mask having a light emitting area of 2 mm × 2 mm) was placed on the electron injection layer, and metal aluminum was formed by vacuum deposition so that the thickness was 100 nm.
The laminate produced as described above was put in a glove box substituted with argon gas, and sealed with a stainless steel sealing can and an ultraviolet curable adhesive (XNR5516HV, manufactured by Nagase Ciba Co., Ltd.). Thus, an organic electroluminescent element of Comparative Example 10-1 was produced.

(Comparative Example 10-2)
Comparative Example 10-1 was the same as Comparative Example 10-1, except that BAlq represented by the above structural formula as the cathode-side adjacent layer was replaced with compound A represented by the following structural formula. 10-2 organic electroluminescent element was produced.

(Comparative Example 10-3)
In Comparative Example 10-1, a comparison was made in the same manner as in Comparative Example 10-1, except that BAlq represented by the above structural formula as the host material of the light emitting layer was replaced with Compound A represented by the above structural formula. The organic electroluminescent element of Example 10-3 was produced.

(Example 10-1)
In Comparative Example 10-1, BAlq represented by the above structural formula as the host material of the light emitting layer is replaced with Compound A represented by the above structural formula, and BAlq represented by the above structural formula as the cathode side adjacent layer. Was replaced with the compound A represented by the above structural formula, and an organic electroluminescent device of Example 10-1 was produced in the same manner as Comparative Example 10-1.

(Comparative Example 11-1)
In Comparative Example 10-1, BAlq represented by the above structural formula as the host material of the light-emitting layer was replaced with mCP (N, N′-dicarbazolyl-3,5-benzene) represented by the following structural formula. The organic electroluminescent element of Comparative Example 11-1 was the same as Comparative Example 10-1, except that BAlq represented by the above structural formula as the side adjacent layer was replaced with Compound B represented by the following structural formula. Was made.

(Comparative Example 11-2)
In Comparative Example 10-1, BAlq represented by the above structural formula as the host material of the light emitting layer was replaced with mCP (N, N′-dicarbazolyl-3,5-benzene) represented by the above structural formula. Produced the organic electroluminescent element of Comparative Example 11-2 in the same manner as Comparative Example 10-1.

(Comparative Example 11-3)
In Comparative Example 10-1, a comparison was made in the same manner as in Comparative Example 10-1, except that BAlq represented by the above structural formula as the host material of the light emitting layer was replaced with Compound B represented by the above structural formula. The organic electroluminescent element of Example 11-3 was produced.

( Reference Example 11-1)
In Comparative Example 10-1, BAlq represented by the above structural formula as the host material of the light-emitting layer is replaced with Compound B represented by the above structural formula, and BAlq represented by the above structural formula as the cathode-side adjacent layer. The organic electroluminescent element of Reference Example 11-1 was produced in the same manner as Comparative Example 10-1, except that Compound B was replaced with Compound B represented by the above structural formula.

(Comparative Example 12-1)
In Comparative Example 10-1, BAlq represented by the above structural formula as the host material of the light-emitting layer was replaced with mCP (N, N′-dicarbazolyl-3,5-benzene) represented by the above structural formula. The organic electroluminescent element of Comparative Example 12-1 was the same as Comparative Example 10-1, except that BAlq represented by the above structural formula as the side adjacent layer was replaced with Compound C represented by the following structural formula. Was made.

(Comparative Example 12-2)
In Comparative Example 10-1, BAlq represented by the above structural formula as the host material of the light emitting layer was replaced with mCP (N, N′-dicarbazolyl-3,5-benzene) represented by the above structural formula. Produced the organic electroluminescent element of Comparative Example 12-2 in the same manner as Comparative Example 10-1.

(Comparative Example 12-3)
In Comparative Example 10-1, a comparison was made in the same manner as in Comparative Example 10-1, except that BAlq represented by the above structural formula as the host material of the light emitting layer was replaced with Compound C represented by the above structural formula. The organic electroluminescent element of Example 12-3 was produced.

( Reference Example 12-1)
In Comparative Example 10-1, BAlq represented by the above structural formula as the host material of the light-emitting layer is replaced with Compound C represented by the above structural formula, and BAlq represented by the above structural formula as the cathode-side adjacent layer. Was replaced with the compound C represented by the above structural formula in the same manner as in Comparative Example 10-1, to prepare an organic electroluminescent element of Reference Example 12-1.

(Comparative Example 13-1)
In Comparative Example 10-1, BAlq represented by the above structural formula as the host material of the light-emitting layer was replaced with mCP (N, N′-dicarbazolyl-3,5-benzene) represented by the above structural formula. The organic electroluminescent element of Comparative Example 13-1 was the same as Comparative Example 10-1, except that BAlq represented by the above structural formula as the side adjacent layer was replaced with Compound D represented by the following structural formula. Was made.

(Comparative Example 13-2)
In Comparative Example 10-1, BAlq represented by the above structural formula as the host material of the light emitting layer was replaced with mCP (N, N′-dicarbazolyl-3,5-benzene) represented by the above structural formula. Produced the organic electroluminescent element of Comparative Example 13-2 in the same manner as Comparative Example 10-1.

(Comparative Example 13-3)
In Comparative Example 10-1, a comparison was made in the same manner as in Comparative Example 10-1, except that BAlq represented by the above structural formula as the host material of the light emitting layer was replaced with Compound D represented by the above structural formula. The organic electroluminescent element of Example 13-3 was produced.

(Example 13-1)
In Comparative Example 10-1, BAlq represented by the above structural formula as the host material of the light-emitting layer is replaced with Compound D represented by the above structural formula, and BAlq represented by the above structural formula as the cathode-side adjacent layer. Was replaced with the compound D represented by the above structural formula, and an organic electroluminescent element of Example 13-1 was produced in the same manner as Comparative Example 10-1.

(Comparative Example 14-1)
In Comparative Example 10-1, BAlq represented by the above structural formula as the host material of the light-emitting layer was replaced with mCP (N, N′-dicarbazolyl-3,5-benzene) represented by the above structural formula. The organic electroluminescent element of Comparative Example 14-1 was the same as Comparative Example 10-1, except that BAlq represented by the above structural formula as the side adjacent layer was replaced with Compound E represented by the following structural formula. Was made.

(Comparative Example 14-2)
In Comparative Example 10-1, BAlq represented by the above structural formula as the host material of the light emitting layer was replaced with mCP (N, N′-dicarbazolyl-3,5-benzene) represented by the above structural formula. Produced the organic electroluminescent element of Comparative Example 14-2 in the same manner as Comparative Example 10-1.

(Comparative Example 14-3)
In Comparative Example 10-1, a comparison was made in the same manner as in Comparative Example 10-1, except that BAlq represented by the above structural formula as the host material of the light emitting layer was replaced with Compound E represented by the above structural formula. The organic electroluminescent element of Example 14-3 was produced.

(Example 14-1)
In Comparative Example 10-1, BAlq represented by the above structural formula as the host material of the light-emitting layer is replaced with Compound E represented by the above structural formula, and BAlq represented by the above structural formula as the cathode-side adjacent layer. Was replaced with the compound E represented by the above structural formula in the same manner as in Comparative Example 10-1, to prepare an organic electroluminescent element of Example 14-1.

(Comparative Example 15-1)
-Fabrication of organic electroluminescence device-
ITO (Indium Tin Oxide) having a thickness of 70 nm was formed as a positive electrode on a 0.5 mm thick, 2.5 cm square glass substrate by sputtering. Next, this ITO-attached glass substrate was put into a cleaning container, subjected to ultrasonic cleaning in 2-propanol, and then subjected to UV-ozone treatment for 30 minutes.
In addition, the vapor deposition rate in the following examples and comparative examples is 0.1 nm / second unless otherwise specified. The deposition rate was measured using a quartz resonator. The thickness of each layer below was measured using a quartz resonator.

First, on the anode (ITO), a hole injection layer in which 30% by mass of MoO ₃ was doped into the compound L represented by the following structural formula was formed by vacuum deposition so that the thickness was 30 nm.

Next, an NPD (N, N′-dinaphthyl-N, N′-diphenyl- [1,1′-biphenyl] -4,4 represented by the following structural formula as a hole transport layer is formed on the hole injection layer. '-Diamine) was formed by vacuum deposition so that the thickness was 10 nm.

Next, mCP (N, N′-dicarbazolyl-3,5-benzene) represented by the following structural formula, which is a host material, and red phosphorescent light-emitting material 4 (peak) represented by the following structural formula with respect to the mCP A light emitting layer doped with 8% by mass of a wavelength of 618 nm) was formed by a vacuum vapor deposition method so as to have a thickness of 30 nm.

Next, a compound 2a-48 represented by the following structural formula as a cathode side adjacent layer was formed on the light emitting layer by a vacuum deposition method so as to have a thickness of 5 nm.

Next, Compound I represented by the following structural formula as an electron transport layer was formed on the cathode side adjacent layer by a vacuum deposition method so as to have a thickness of 45 nm.

Next, lithium fluoride (LiF) was formed as an electron injection layer on the electron transport layer by a vacuum deposition method so as to have a thickness of 1 nm.
Next, a mask patterned as a cathode (a mask having a light emitting area of 2 mm × 2 mm) was placed on the electron injection layer, and metal aluminum was formed by vacuum deposition so that the thickness was 100 nm.
The laminate produced as described above was put in a glove box substituted with argon gas, and sealed with a stainless steel sealing can and an ultraviolet curable adhesive (XNR5516HV, manufactured by Nagase Ciba Co., Ltd.). Thus, an organic electroluminescent element of Comparative Example 15-1 was produced.

(Comparative Example 15-2)
In Comparative Example 15-1, Compound 2a-48 represented by the above structural formula as the cathode-side adjacent layer was converted to BAlq [Bis- (2-methyl-8-quinolinolato) -4- ( The organic electroluminescent element of Comparative Example 15-2 was produced in the same manner as Comparative Example 15-1, except that it was changed to (phenyl-phenolate) -aluminum (III)].

(Comparative Example 15-3)
In Comparative Example 15-1, mCP (N, N′-dicarbazolyl-3,5-benzene) represented by the above structural formula as a host material for the light-emitting layer was converted into Compound 2a-48 represented by the above structural formula. Instead, Comparative Example 15-3 was carried out in the same manner as Comparative Example 15-1, except that Compound 2a-48 represented by the above structural formula as the cathode-side adjacent layer was replaced with BAlq represented by the above structural formula. An organic electroluminescent element was prepared.

(Example 15-1)
In Comparative Example 15-1, mCP (N, N′-dicarbazolyl-3,5-benzene) represented by the above structural formula as a host material for the light-emitting layer was converted into Compound 2a-48 represented by the above structural formula. Instead of Example 15- in the same manner as Comparative Example 15-1, except that Compound 2a-48 represented by the above structural formula as the cathode side adjacent layer was replaced with Compound E represented by the following structural formula. 1 organic electroluminescent element was produced.

(Comparative Example 16-1)
In Comparative Example 15-1, Comparative Example 15-1 except that Compound 2a-48 represented by the above structural formula as the cathode-side adjacent layer was replaced by Compound 2a′-60 represented by the following structural formula Similarly, the organic electroluminescent element of Comparative Example 16-1 was produced.

(Comparative Example 16-2)
In Comparative Example 15-1, except that Compound 2a-48 represented by the above structural formula as the cathode side adjacent layer was replaced with BAlq represented by the above structural formula, in the same manner as Comparative Example 15-1, An organic electroluminescent element of Comparative Example 16-2 was produced.

(Comparative Example 16-3)
In Comparative Example 15-1, mCP (N, N′-dicarbazolyl-3,5-benzene) represented by the above structural formula as a host material for the light-emitting layer was replaced by Compound 2a′-60 represented by the above structural formula. In the same manner as in Comparative Example 15-1, except that Compound 2a-48 represented by the above structural formula as the cathode-side adjacent layer was replaced with BAlq represented by the above structural formula, Comparative Example 16- 3 organic electroluminescent elements were produced.

(Example 16-1)
In Comparative Example 15-1, mCP (N, N′-dicarbazolyl-3,5-benzene) represented by the above structural formula as a host material for the light-emitting layer was replaced by Compound 2a′-60 represented by the above structural formula. Instead of compound 2a-48 represented by the above structural formula as the cathode side adjacent layer in place of compound 2a′-60 represented by the above structural formula, in the same manner as in Comparative Example 15-1, The organic electroluminescent element of Example 16-1 was produced.

  Next, the device performance and the change in chromaticity over time were measured for the produced Examples and Comparative Examples as follows. The results are shown in Table 1, Table 2, Table 3, and Table 4.

<Element performance>
-Driving voltage (V)-
Using a source measure unit type 2400 manufactured by KEITHLEY, a driving voltage at a luminance of 1,000 cd when a direct current was applied was measured.

-External quantum efficiency (EQE)-
Using a source measure unit type 2400 manufactured by KEITHLEY, each element was supplied with a direct current having a current density of 25 mA / cm ² to emit light. The luminance and emission spectrum at 1,000 cd were measured using a luminance meter SR-3 manufactured by Topcon Corporation. Based on these measurement results, the external quantum efficiency was calculated by an emission spectrum conversion method.

-Drive durability (luminance half time)-
Each organic electroluminescent element is driven at a constant current until the luminance is halved at an initial luminance of 5,000 cd / m ² , and the luminance half-life (t ₅₀₀₀ ) is measured. From the luminance half-life of 5,000 cd / m ^2, a power law of 1.5 was assumed, and the luminance half-life of 1,000 cd / m ² was calculated from the following formula.
t ₁₀₀₀ = t ₅₀₀₀ × ( _5,000 cd / 1,000 cd) ^1.5

<Chromaticity change over time>
Each organic electroluminescent element is driven at a constant current until the luminance is reduced by half at an initial luminance of 3,000 cd, and the change in chromaticity (Δx and Δy) at 1,000 cd at the initial and half-time is measured by Topcon's luminance meter SR-3. It was measured by. Note that the smaller the chromaticity change (Δx and Δy), the smaller the chromaticity change over time.

  The organic electroluminescent device of the present invention has improved device performance such as luminous efficiency, driving voltage, and driving durability, and can suppress chromaticity change at the time of device degradation. For example, a display device, a display, a backlight, It is suitably used for electrophotography, illumination light source, recording light source, exposure light source, reading light source, sign, signboard, interior, optical communication and the like.

DESCRIPTION OF SYMBOLS 1 Board | substrate 2 Anode 3 Hole injection layer 4 Hole transport layer 5 Electron block layer 6 Light emitting layer 7 Cathode side adjacent layer 8 Electron transport layer 9 Electron injection layer 10 Cathode 11 Organic electroluminescent element

Claims (9)

An organic layer including at least one light emitting layer and a cathode side adjacent layer adjacent to the cathode side of the light emitting layer between the anode and the cathode;
The light emitting layer contains a red phosphorescent material and a compound or Ranaru host material having a non-nitrogen-containing anthracene derivative skeleton,
The cathode side adjacent layer contains a compound having a non-nitrogen-containing anthracene derivative skeleton , and the cathode side adjacent layer has a thickness of 1 nm to 10 nm,
An organic electroluminescent device , wherein the compound having a non-nitrogen-containing anthracene derivative skeleton in the host material and the compound having a non-nitrogen-containing anthracene derivative skeleton in the cathode-side adjacent layer are the same compound . An organic layer including at least one light emitting layer and a cathode side adjacent layer adjacent to the cathode side of the light emitting layer between the anode and the cathode;
The light emitting layer contains a red phosphorescent light emitting material and a host material made of a compound having a pyrene derivative skeleton,
The cathode side adjacent layer contains a compound having a pyrene derivative skeleton,
An organic electroluminescent device, wherein the compound having a pyrene derivative skeleton in the host material and the compound having a pyrene derivative skeleton in the cathode-side adjacent layer are the same compound. The organic electroluminescent element according to claim 1, wherein the compound having a non-nitrogen-containing anthracene derivative skeleton in the light emitting layer and the cathode side adjacent layer is represented by the following general formula (I).
However, in the general formula (I), Ar ¹ And Ar ² Are each independently a group derived from a substituted or unsubstituted aromatic ring having 6 to 20 nuclear carbon atoms. The aromatic ring may be substituted with one or more substituents. The substituent is a substituted or unsubstituted aryl group having 6 to 50 nuclear carbon atoms, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 50 carbon atoms, a substituted group. Or an unsubstituted alkoxy group having 1 to 50 carbon atoms, a substituted or unsubstituted aralkyl group having 6 to 50 nuclear carbon atoms, a substituted or unsubstituted aryloxy group having 5 to 50 nuclear atoms, a substituted or unsubstituted nucleus. It is selected from an arylthio group having 5 to 50 atoms, a substituted or unsubstituted alkoxycarbonyl group having 1 to 50 carbon atoms, a substituted or unsubstituted silyl group, a carboxyl group, a halogen atom, a cyano group, a nitro group, and a hydroxy group. When the aromatic ring is substituted with two or more substituents, the substituents may be the same or different, and adjacent substituents are bonded to each other to form a saturated or unsaturated cyclic structure. May be formed.
R ¹ To R ⁸ Is a hydrogen atom, a substituted or unsubstituted aryl group having 6 to 50 nuclear carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 50 nuclear atoms, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, A substituted or unsubstituted cycloalkyl group having 3 to 50 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 50 carbon atoms, a substituted or unsubstituted aralkyl group having 6 to 50 carbon atoms, a substituted or unsubstituted nucleus atom An aryloxy group having 5 to 50 atoms, a substituted or unsubstituted arylthio group having 5 to 50 nucleus atoms, a substituted or unsubstituted alkoxycarbonyl group having 1 to 50 carbon atoms, a substituted or unsubstituted silyl group, a carboxyl group, It is selected from a halogen atom, a cyano group, a nitro group and a hydroxy group. Further, adjacent substituents may be bonded to each other to form a saturated or unsaturated cyclic structure. The organic electroluminescent element according to claim 2, wherein the compound having a pyrene derivative skeleton in the light emitting layer and the cathode side adjacent layer is represented by the following general formula (II).
However, in the general formula (II), Ar ^1a And Ar ^2a Each represents a substituted or unsubstituted aromatic ring group having 6 to 50 nuclear carbon atoms.
L is a substituted or unsubstituted phenylene group, a substituted or unsubstituted naphthalenylene group, a substituted or unsubstituted fluorenylene group, or a substituted or unsubstituted dibenzosilolylene group, respectively.
m is an integer of 0 to 2, nb is an integer of 1 to 4, s is an integer of 0 to 2, and t is an integer of 0 to 4.
L or Ar ^1a Is bonded to any one of positions 1 to 5 of pyrene, and L or Ar ^2a Binds to any of positions 6-10 of pyrene.
However, when nb + t is an even number, Ar ^1a , Ar ^2a , L satisfies the following (1) or (2).
(1) Ar ^1a ≠ Ar ^2a (Here, ≠ indicates a group having a different structure.)
(2) Ar ^1a = Ar ^2a time
(2-1) m ≠ s and / or nb ≠ t, or
(2-2) When m = s and nb = t,
(2-2-1) L or pyrene is each Ar ^1a And Ar ^2a Are connected to different bond positions above,
(2-2-2) L or pyrene is Ar ^1a And Ar ^2a L or Ar when bonded to the same bond position above ^1a And Ar ^2a There are no cases in which the substitution positions in the pyrene are 1-position and 6-position, or 2-position and 7-position. The compound having a non-nitrogen-containing anthracene derivative skeleton in the light emitting layer and the cathode side adjacent layer is represented by R in the general formula (I): ¹ To R ⁸ Is a hydrogen atom and Ar ¹ And Ar ² The organic electroluminescent element according to claim 3, wherein is an unsubstituted compound. The compound having a pyrene derivative skeleton in the light emitting layer and the cathode side adjacent layer is represented by ((L) m-Ar ^1a ) Nb and ((L) s-Ar ^2a ) The position where t is not bonded is a hydrogen atom, and ((L) m-Ar ^1a ) Nb and ((L) s-Ar ^2a The organic electroluminescent device according to claim 4, wherein t is unsubstituted. 6. The organic electroluminescence device according to claim 3, wherein the compound having a non-nitrogen-containing anthracene derivative skeleton in the light-emitting layer and the cathode-side adjacent layer is a non-nitrogen-containing anthracene derivative compound having no lone pair. The organic electroluminescent element according to claim 4, wherein the compound having a pyrene derivative skeleton in the light emitting layer and the cathode side adjacent layer is a compound having a pyrene derivative skeleton having no lone pair. The organic electroluminescence according to any one of claims 1 to 8, wherein the red phosphorescent material is an organometallic complex whose central metal is at least one of ruthenium, rhodium, palladium, tungsten, rhenium, osmium, iridium and platinum. element.