JP2009170809A - Organic electroluminescent element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve luminous efficiency and durability in "an organic electroluminescent element using a phosphorescent material" containing a phosphorescent material in a luminous layer. <P>SOLUTION: In the organic electroluminescent element, functional layers containing the luminous layer are sandwiched between a pair of electrodes, the luminous layer contains a phosphorescent material, and one of the functional layers contains at least one type of compound expressed by general formula (1). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an organic electroluminescent device.

  Electroluminescent devices that use electroluminescence are self-luminous compared to liquid crystal displays and thus have high visibility and high-speed responsiveness, so that they can display clear images when used in displays. In addition, since it is an all solid-state device, it has characteristics such as excellent impact resistance. Therefore, in recent years, it is expected to be widely used for thin displays, liquid crystal display backlights, flat light sources, and the like.

  Electroluminescent devices can be broadly classified into inorganic electroluminescent devices and organic electroluminescent devices, depending on the constituent materials. The inorganic electroluminescent device is a dispersive electroluminescent device using an inorganic material such as zinc sulfide. The driving method of this dispersive electroluminescent device is that an accelerated electron collides and excites the emission center by applying a high electric field. Therefore, it is necessary to drive with a high AC voltage. Therefore, there are problems such as a complicated driving circuit and low luminance.

  On the other hand, an organic electroluminescence device (organic electroluminescence device: organic EL device) emits light by recombining charges (holes and electrons) injected from an electrode in a light emitting layer made of an organic compound. Because it is “light emission”, it can be driven at a low voltage (Non-patent Document 1 and Patent Document 1). Further, there is an advantage that an arbitrary emission color and characteristics can be easily changed by changing the molecular design of the organic compound. For this reason, various materials and element configurations have been proposed at present, and research and development has been activated.

  On the other hand, various problems and problems still remain in the organic electroluminescent devices using the materials proposed so far. For example, there is a problem in the light emission life that the function of the element deteriorates and the light emission luminance decreases only by storing, regardless of the drive state or the non-drive state. In general, the emission luminance is still low, which is not sufficient for practical use.

  As a method for improving emission luminance, an organic electroluminescence device using tris (8-quinolinolato) aluminum or the like as a host material in a light emitting layer, a coumarin derivative or a pyran derivative as a guest compound (Non-patent Document 2), and a guest compound An organic electroluminescent device using N, N-dimethylquinacridone (for example, Non-Patent Document 3) and an organic electroluminescent device using rubrene as a guest compound (for example, Non-Patent Document 4) have been proposed.

  These organic electroluminescence emits light when an organic molecule forms an excited state by recombination of carrier electrons and holes injected from an electric field and falls to a ground state. In this case, the excited organic molecule takes a high energy excited singlet state (electrons are reverse spin) and a low energy excited triplet state (electrons are the same spin).

  In recent years, organic phosphorescent materials have attracted attention as a material for improving luminous efficiency in research on organic electroluminescent devices. It has also been proposed to use a phosphorescent material as a guest material for the light emitting layer of the organic EL element (Non-patent Documents 5 and 6). In general, in the phosphorescence process, an organic molecule is excited from a ground state to a singlet excited state, and then a non-radiative transition called intersystem crossing from a singlet excited state to a triplet excited state occurs. Phosphorescence emission shows light emission of triplet excited state → ground state.

  It is expected that high luminous efficiency can be achieved by using the singlet excited state and the triplet excited state of the organic phosphorescent material in the light emitting layer of the organic electroluminescent element. The reason for using the triplet excited state is that when electrons and holes are recombined in the organic electroluminescent device, the ratio of singlet excitons and triplet excitons is 3: 1 due to the difference in spin multiplicity. This is because it is considered to achieve a luminous efficiency three times that of an element using fluorescence.

  In recent years, in order to improve the light emission efficiency and durability of organic electroluminescence devices using phosphorescence, improvements have been actively made on the host material of the organic light emitting layer and the material of the layer adjacent to the light emitting layer. For example, a light-emitting layer including a phosphorescent material may be formed using 4,4′-bis (N-carbazolyl) -1,1′-biphenyl (also referred to as “CBP”) or 1,3-bis (N-carbazolyl) benzene ( It is well known to use a carbazole derivative typified by “m-CP”) as a host material. However, it is still difficult to say that it has sufficient performance, and further improvements in efficiency and durability are desired (see, for example, Patent Documents 2 and 3).

Furthermore, a technique is also known in which an amine compound having a fluorenyl skeleton is contained in a light emitting layer of an organic electroluminescent element (for example, see Patent Document 4).
Appl.Phys.Lett., 51,913 (1987) J.Appl.Phys., 65,3610 (1989) Appl.Phys.Lett., 70,1665 (1997) Jpn.J.Appl.Phys., 34, L824 (1995) Appl.Phys.Lett., 74,442 (1999) Appl.Phys.Lett., 75,4 (1999) Japanese Unexamined Patent Publication No. 63-264692 International Publication No. 03/80760 Pamphlet WO04 / 74399 pamphlet Japanese Patent Laid-Open No. 11-224779

  An object of the present invention is to improve the luminous efficiency and durability of an “organic electroluminescent device using a phosphorescent material” containing a phosphorescent material in a light emitting layer.

  In the “organic electroluminescent device using a phosphorescent light emitting material” containing a phosphorescent light emitting material in the light emitting layer, the inventor includes a specific compound as a host compound contained in the light emitting layer, or an anode of the light emitting layer. It has been found that when it is contained in the hole injection transport layer adjacent to the side, the luminous efficiency and durability of the organic electroluminescence device are improved.

That is, this invention relates to the organic electroluminescent element shown below.
[1] An organic electroluminescent device comprising a functional layer including a light emitting layer sandwiched between a pair of electrodes,
The light emitting layer contains a phosphorescent material;
Any one of the functional layers is an organic electroluminescent device containing at least one compound represented by the general formula (1) (Chemical Formula 1).

（式（１）において、
Ａｒ₁ 〜Ａｒ₄ は、置換または未置換のアリール基を表し、
Ａｒ₁ とＡｒ₂、およびＡｒ₃ とＡｒ₄ は、結合している窒素原子と共に含窒素複素環を形成していてもよく、
Ｒ₁ およびＲ₂は、水素原子、直鎖、分岐または環状のアルキル基、置換または未置換のアリール基、あるいは置換または未置換のアラルキル基を表し、
Ｚ₁ およびＺ₂は、水素原子、ハロゲン原子、直鎖、分岐または環状のアルキル基、直鎖、分岐または環状のアルコキシ基、あるいは置換または未置換のアリール基を表し、
Ｘ₁ およびＸ₂ は置換または未置換のアリーレン基を表す）

(In Formula (1),
Ar _{1 to} Ar ₄ represent a substituted or unsubstituted aryl group,
Ar ₁ and Ar ₂ , and Ar ₃ and Ar ₄ may form a nitrogen-containing heterocycle together with the nitrogen atom to which they are bonded,
R ₁ and R ₂ represent a hydrogen atom, a linear, branched or cyclic alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group,
Z ₁ and Z ₂ represent a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group, a linear, branched or cyclic alkoxy group, or a substituted or unsubstituted aryl group,
X ₁ and X ₂ represent a substituted or unsubstituted arylene group)

  [2] The organic electroluminescent element according to [1], wherein the layer containing the compound represented by the general formula (1) is a light emitting layer or a hole injection transport layer.

  According to the present invention, it is possible to provide an organic electroluminescent element using a phosphorescent material having excellent luminous efficiency and durability.

  The organic electroluminescent element of the present invention has a pair of electrodes, and a functional layer having at least a light emitting layer is sandwiched between the pair of electrodes. The light emitting layer contains a phosphorescent material. The functional layer sandwiched between the pair of electrodes includes a charge injection transport layer according to a hole injection function and a hole transport function, and an electron injection function and an electron transport function of the compound included in the light emitting layer. Can be. The charge injection transport layer is a hole injection transport layer containing a hole injection component (arranged on the anode side of the light emitting layer) or an electron injection transport layer containing an electron injection transport component (on the cathode side of the light emitting layer). Arranged).

When the hole injection function, hole transport function, electron injection function, and electron transport function of the compound contained in the light emitting layer are high, a single-layer device (no electron injection transport layer) having only the light emitting layer may be used. it can. In the single-layer device, the light emitting layer has a function of a hole injecting and transporting layer and / or an electron injecting and transporting layer.
Moreover, when the hole injection function and hole transport function of the compound contained in the light emitting layer are not sufficient, it is preferable to use a two-layer element in which a hole injection transport layer is provided on the anode side of the light emitting layer. On the other hand, when the electron injection function and the electron transport function of the compound contained in the light emitting layer are not sufficient, a two-layer device in which an electron injection transport layer is provided on the cathode side of the light emitting layer can be obtained. Of course, a three-layered device in which the light emitting layer is sandwiched between a hole injecting and transporting layer and an electron injecting and transporting layer can also be used.

  In addition, each of the hole injecting and transporting layer, the electron injecting and transporting layer, and the light emitting layer may have a single layer structure or a multilayer structure. Each of the hole injection / transport layer and the electron injection / transport layer may have a layer having an injection function and a layer having a transport function.

More specifically, examples of the structure of the organic light emitting device of the present invention are shown in FIGS. 1 to 8, but are not particularly limited thereto.
FIG. 1 shows an element (EL-1) including a substrate 1 / anode 2 / hole injection / transport layer 3 / light emitting layer 4 / electron injection / transport layer 5 / cathode 6 and a power source 7; FIG. 1 / anode 2 / hole injection transport layer 3 / light emitting layer 4 / cathode 6 and an element (EL-2) including a power source 7; FIG. 3 shows a substrate 1 / anode 2 / light emitting layer 4 / electron injection transport. Layer 5 / cathode 6 and element (EL-3) including power source 7; FIG. 4 shows substrate 1 / anode 2 / light emitting layer 4 / cathode type 6 and element (EL-4) including power source 7. Indicated.

  FIG. 5A shows an element (EL-5A) including a substrate 1 / anode 2 / hole injection layer 3 ′ / hole transport layer 3 ″ / light emitting layer 4 / electron injection transport layer 5 / cathode 6 and a power source 7. Indicated.

  On the other hand, FIG. 5B includes substrate 1 / anode 2 / hole injection transport layer 3 / light emitting layer 4 / hole blocking layer (electron transport layer) 5 ′ / electron injection transport layer 5 / cathode 6 and power source 7. An element (EL-5B) is shown.

  5C shows substrate 1 / anode 2 / hole injection layer 3 ′ / hole transport layer 3 ″ / light emitting layer 4 / hole blocking layer (electron transport layer) 5 ′ / electron injection transport layer 5 / cathode. 6 and an element (EL-5C) including a power source 7 is shown.

  6 to 8 show an element similar to EL-4. That is, FIG. 6 shows an element (EL-6) of a type in which a light emitting layer in which a hole injecting and transporting component 3a, a light emitting component 4a, and an electron injecting component 5a are mixed is sandwiched between a pair of electrodes; FIG. 7 shows a device (EL-7) of a type in which a light emitting layer obtained by mixing a hole injecting and transporting component 3a and a light emitting component 4a is sandwiched between a pair of electrodes; As shown, a light emitting layer (EL-8) in which a light emitting layer in which a light emitting component 4a and an electron injecting and transporting component 5a are mixed is sandwiched between a pair of electrodes is shown.

  Preferred element configurations of the organic electroluminescent element of the present invention are (EL-1) type element, (EL-2) type element, (EL-3) type element, (EL-5A) type element, (EL-5B). Type element, (EL-5C) type element, (EL-6) type element or (EL-7) type element, more preferably (EL-1) type element, (EL-2) type element, ( EL-5A) type element, (EL-5B) type element, (EL-5C) type element or (EL-7) type element.

  Of course, the element structure of the organic electroluminescent element of the present invention is not limited thereto. In each type of element, a plurality of hole injection / transport layers, light emitting layers, and electron injection / transport layers may be provided. In each type of device, a mixed layer of a light emitting component and a hole injecting and transporting component may be provided between the hole injecting and transporting layer and the light emitting layer, and between the electron injecting and transporting layer and the light emitting layer. A mixed layer of the light emitting component and the electron injection / transport component may be provided.

Phosphorescent material The light emitting layer of the organic light emitting device of the present invention contains a phosphorescent material. The phosphorescent light emitting material preferably acts as a dopant material (or guest material) in the light emitting layer. The phosphorescent materials contained in the light emitting layer may be used singly or in combination of two or more. The phosphorescent material is not particularly limited but is preferably a transition metal complex. Examples of the transition metal complex include compounds represented by the following general formula (a-1) or general formula (a-2).

M ₁ in the general formula (a-1) represents an m-valent metal atom, and preferably represents ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, or gold.

A ₁ in the general formula (a-1) represents an atomic group for forming a 5-membered or 6-membered nitrogen-containing heterocycle. The formed nitrogen-containing heterocycle may have a substituent. Preferable examples of the nitrogen-containing heterocycle include pyridyl, pyrimidyl, pyrazine, triazine, benzothiazole, benzoxazole, benzimidazole, quinolyl, isoquinolyl, quinoxaline, phenanthrylene and the like.

A ₂ in the general formula (a-1) represents an atomic group for forming a 5-membered or 6-membered cyclic structure. The formed cyclic structure is an aromatic hydrocarbon ring or an aromatic heterocyclic ring, and may have a substituent. Preferable examples of the aromatic hydrocarbon ring or aromatic heterocyclic ring include phenyl, biphenyl, naphthyl, anthryl, thienyl, pyridyl, quinolyl, isoquinolyl and the like.

Examples of the substituent of A ₁ or A ₂ in the general formula (a-1) include a halogen atom such as a fluorine atom; an alkyl group having 1 to 6 carbon atoms such as a methyl group and an ethyl group; a vinyl group and an allyl group. C2-C6 alkenyl group such as methoxycarbonyl group and ethoxycarbonyl group; C2-C6 alkoxycarbonyl group such as methoxycarbonyl group and ethoxycarbonyl group; C1-C6 alkoxy group such as methoxy group and ethoxy group; Phenoxy group and benzyl Aryloxy groups such as oxy groups; dialkylamine groups such as dimethylamino groups and diethylamino groups; acyl groups such as acetyl groups; haloalkyl groups such as trifluoromethyl groups; cyano groups and the like.

L and L ′ represent an atom capable of coordinating to M ₁ , and a dotted line connecting L and L ′ represents that a bond may be formed or separated. N _d represents an integer of 1 to m.

On the other hand, in General Formula (a-2), V _{1 to} V ₈ represent a hydrogen atom, an alkyl group, or a substituent selected from an aryl group; Y _{1 to} Y ₄ represent CV ₉ (V ₉ Represents a hydrogen atom, an alkyl group, or an aryl group), or represents a nitrogen atom; M ₂ represents a metal atom.

  Specific examples of the phosphorescent material represented by the general formula (a-1) or the general formula (a-2) are shown below, but are not limited to the following compounds.

  When the light emitting layer containing a phosphorescent material contains a compound represented by the general formula (1) and / or a compound having a light emitting function other than the compound represented by the general formula (1) as a host compound, phosphorescent light emission The content of the material is preferably 0.001 to 40% by weight, more preferably 0.01 to 30% by weight, and more preferably 0.1 to 20% by weight with respect to the host compound. Further preferred.

  The content of the compound having a light emitting function other than the general formula (1) in the light emitting layer is preferably 0.001 to 40% by weight with respect to the compound represented by the general formula (1). It is more preferably ˜30% by weight, and further preferably 0.1˜20% by weight.

Compound represented by general formula (1) The organic electroluminescent element of the present invention contains the compound represented by general formula (1) in at least one of the functional layers sandwiched between a pair of electrodes. . The compound represented by the general formula (1) is preferably contained in the hole injecting and transporting layer and / or the light emitting layer, and more preferably contained in the light emitting layer. The compound represented by the general formula (1) contained in the light emitting layer preferably acts as a host material.

Ar _{1 to} Ar ₄ in Formula (1) represent a substituted or unsubstituted aryl group, and Ar ₁ and Ar ₂ , and Ar ₃ and Ar ₄ form a nitrogen-containing heterocycle together with the nitrogen atom to which Ar ₁ and Ar ₄ are bonded. Also good.

Examples of the aryl group of Ar _{1 to} Ar ₄ include carbocyclic aromatic groups such as phenyl group, naphthyl group, and anthryl group, and heterocyclic aromatic groups such as furyl group, thienyl group, and pyridyl group. . The aryl group of Ar _{1 to} Ar ₄ is preferably not a condensed ring but a monocyclic aryl group (such as a phenyl group).

Ar _{1 to} Ar ₄ are unsubstituted; or a carbocyclic aromatic group or total carbon having a total carbon number of 6 to 20, which is mono-substituted or poly-substituted with a halogen atom, an alkyl group, an alkoxy group or an aryl group It is preferably a heterocyclic aromatic group having a number of 3 to 20.

Ar _{1 to} Ar ₄ are unsubstituted or monosubstituted or polysubstituted with a halogen atom, an alkyl group having 1 to 14 carbon atoms, an alkoxy group having 1 to 14 carbon atoms, or an aryl group having 6 to 10 carbon atoms. And more preferably a carbocyclic aromatic group having 6 to 20 carbon atoms in total; unsubstituted or halogen atom, alkyl group having 1 to 4 carbon atoms, alkoxy group having 1 to 4 carbon atoms Or a carbocyclic aromatic group having 6 to 16 carbon atoms, which is mono- or polysubstituted with an aryl group having 6 to 10 carbon atoms.

R ₁ and R ₂ in Formula (1) represent a hydrogen atom; a linear, branched or cyclic alkyl group; a substituted or unsubstituted aryl group; or a substituted or unsubstituted aralkyl group. Z ₁ and Z ₂ in Formula (1) represent a hydrogen atom; a halogen atom; a linear, branched or cyclic alkyl group; a linear, branched or cyclic alkoxy group; or a substituted or unsubstituted aryl group. X ₁ and X ₂ in Formula (1) represent a substituted or unsubstituted arylene group.

A _first specific example of Ar _{1 to} Ar ₄ is an unsubstituted or substituted phenyl group. That is, examples of Ar _{1 to} Ar ₄ include an unsubstituted phenyl group; a phenyl group having an alkyl group; a phenyl group having an alkoxy group; a phenyl group having an aryl group; a phenyl group having a halogen atom;

  Examples of the phenyl group having an alkyl group include 4-methylphenyl group, 3-methylphenyl group, 2-methylphenyl group, 4-ethylphenyl group, 3-ethylphenyl group, 2-ethylphenyl group, 4-n 4-propylphenyl group, 4-isopropylphenyl group, 2-isopropylphenyl group, 4-n-butylphenyl group, 4-isobutylphenyl group, 4-sec-butylphenyl group, 2-sec-butylphenyl group, 4-tert -Butylphenyl group, 3-tert-butylphenyl group, 2-tert-butylphenyl group, 4-n-pentylphenyl group, 4-isopentylphenyl group, 2-neopentylphenyl group, 4-tert-pentylphenyl group 4-n-hexylphenyl group, 4- (2′-ethylbutyl) phenyl group, 4-n-heptylphenyl group, 4-n-octylphenyl group, 4- (2′-ethylhexyl) phenyl group, 4-tert -O Tylphenyl group, 4-n-decylphenyl group, 4-n-dodecylphenyl group, 4-n-tetradecylphenyl group, 4-cyclopentylphenyl group, 4-cyclohexylphenyl group, 4- (4'-methylcyclohexyl) phenyl Group, 4- (4′-tert-butylcyclohexyl) phenyl group, 3-cyclohexylphenyl group, 2-cyclohexylphenyl group, 4-ethyl-1-naphthyl group, 6-n-butyl-2-naphthyl group, 2, 4-dimethylphenyl group, 2,5-dimethylphenyl group, 3,4-dimethylphenyl group, 3,5-dimethylphenyl group, 2,6-dimethylphenyl group, 2,4-diethylphenyl group, 2,3, 5-trimethylphenyl group, 2,3,6-trimethylphenyl group, 3,4,5-trimethylphenyl group, 2,6-diethylphenyl group, 2,5-diisopropylphenyl group, 2,6-diisobutyl group Nyl group, 2,4-di-tert-butylphenyl group, 2,5-di-tert-butylphenyl group, 4,6-di-tert-butyl-2-methylphenyl group, 5-tert-butyl-2 -Methylphenyl group, 4-tert-butyl-2,6-dimethylphenyl group and the like are included.

  Examples of the phenyl group having an alkoxy group include 4-methoxyphenyl group, 3-methoxyphenyl group, 2-methoxyphenyl group, 4-ethoxyphenyl group, 3-ethoxyphenyl group, 2-ethoxyphenyl group, 4-n -Propoxyphenyl group, 3-n-propoxyphenyl group, 4-isopropoxyphenyl group, 2-isopropoxyphenyl group, 4-n-butoxyphenyl group, 4-isobutoxyphenyl group, 2-sec-butoxyphenyl group, 4-n-pentyloxyphenyl group, 4-isopentyloxyphenyl group, 2-isopentyloxyphenyl group, 4-neopentyloxyphenyl group, 2-neopentyloxyphenyl group, 4-n-hexyloxyphenyl group, 2- (2′-ethylbutyl) oxyphenyl group, 4-n-octyloxyphenyl group, 4-n-decyloxyphenyl group, 4-n-do Decyloxyphenyl group, 4-n-tetradecyloxyphenyl group, 4-cyclohexyloxyphenyl group, 2-cyclohexyloxyphenyl group, 2-methyl-4-methoxyphenyl group, 2-methyl-5-methoxyphenyl group, 3 -Methyl-5-methoxyphenyl group, 3-ethyl-5-methoxyphenyl group, 2-methoxy-4-methylphenyl group, 3-methoxy-4-methylphenyl group, 2,4-dimethoxyphenyl group, 2,5 -Dimethoxyphenyl group, 2,6-dimethoxyphenyl group, 3,4-dimethoxyphenyl group, 3,5-dimethoxyphenyl group, 3,5-diethoxyphenyl group, 3,5-di-n-butoxyphenyl group, 2-methoxy-4-ethoxyphenyl group, 2-methoxy-6-ethoxyphenyl group, 3,4,5-trimethoxyphenyl group and the like are included.

  Examples of the phenyl group having an aryl group include 4-phenylphenyl group, 3-phenylphenyl group, 2-phenylphenyl group, 4- (4′-methylphenyl) phenyl group, 4- (3′-methylphenyl) Phenyl group, 4- (4′-methoxyphenyl) phenyl group, 4- (4′-n-butoxyphenyl) phenyl group, 2- (2′-methoxyphenyl) phenyl group, 4- (4′-chlorophenyl) phenyl The group includes 3-methyl-4-phenylphenyl group and 3-methoxy-4-phenylphenyl group.

  Examples of the phenyl group having a halogen atom include 4-fluorophenyl group, 3-fluorophenyl group, 2-fluorophenyl group, 4-chlorophenyl group, 3-chlorophenyl group, 2-chlorophenyl group, 4-bromophenyl group, 2-bromophenyl group, 2,3-difluorophenyl group, 2,4-difluorophenyl group, 2,5-difluorophenyl group, 2,6-difluorophenyl group, 3,4-difluorophenyl group, 3,5- Difluorophenyl group, 2,3-dichlorophenyl group, 2,4-dichlorophenyl group, 2,5-dichlorophenyl group, 3,4-dichlorophenyl group, 3,5-dichlorophenyl group, 2,5-dibromophenyl group, 2,4 , 6-trichlorophenyl group, 2-fluoro-4-methylphenyl group, 2-fluoro-5-methylphenyl group, 3-fluoro-2-methylphenyl group, 3-fluoro-4 -Methylphenyl group, 2-methyl-4-fluorophenyl group, 2-methyl-5-fluorophenyl group, 3-methyl-4-fluorophenyl group, 2-chloro-4-methylphenyl group, 2-chloro-5 -Methylphenyl group, 2-chloro-6-methylphenyl group, 2-methyl-3-chlorophenyl group, 2-methyl-4-chlorophenyl group, 3-methyl-4-chlorophenyl group, 2-chloro-4,6- Dimethylphenyl group, 2-methoxy-4-fluorophenyl group, 2-fluoro-4-methoxyphenyl group, 2-fluoro-4-ethoxyphenyl group, 2-fluoro-6-methoxyphenyl group, 3-fluoro-4- Examples include ethoxyphenyl group, 3-chloro-4-methoxyphenyl group, 2-methoxy-5-chlorophenyl group, 3-methoxy-6-chlorophenyl group, 5-chloro-2,4-dimethoxyphenyl group, and the like.

A second specific example of Ar _{1 to} Ar ₄ is an unsubstituted or substituted naphthyl group. Examples of naphthyl groups include 1-naphthyl group, 2-naphthyl group, 2-methoxy-1-naphthyl group, 4-methoxy-1-naphthyl group, 4-n-butoxy-1-naphthyl group, 5-ethoxy- 1-naphthyl group, 6-methoxy-2-naphthyl group, 6-ethoxy-2-naphthyl group, 6-n-butoxy-2-naphthyl group, 6-n-hexyloxy-2-naphthyl group, 7-methoxy- 2-naphthyl group, 7-n-butoxy-2-naphthyl group, 4-chloro-1-naphthyl group, 4-chloro-2-naphthyl group, 6-bromo-2-naphthyl group, 2,4-dichloro-1 -Naphthyl group, 1,6-dichloro-2-naphthyl group and the like are included.

A third specific example of Ar _{1 to} Ar ₄ is an unsubstituted or substituted fluorenyl group. Examples of fluorenyl groups include 2-fluorenyl, 9-methyl-2-fluorenyl, 9-ethyl-2-fluorenyl, 9-n-hexyl-2-fluorenyl, 9,9-dimethyl-2-fluorenyl. Groups, 9,9-diethyl-2-fluorenyl group, 9,9-di-n-propyl-2-fluorenyl group, 9-phenyl-2-fluorenyl group and the like.

Other specific examples of Ar _{1 to} Ar ₄ include 2-anthryl group, 9-anthryl group, 4-quinolyl group, 4-pyridyl group, 3-pyridyl group, 2-pyridyl group, 3-furyl group, 2- Furyl group, 3-thienyl group, 2-thienyl group, 2-oxazolyl group, 2-thiazolyl group, 2-benzoxazolyl group, 2-benzothiazolyl group, 2-benzoimidazolyl group, etc. You may have.

In General Formula (1), —NAr ₁ Ar ₂ or —NAr ₃ Ar ₄ may form a nitrogen-containing heterocyclic ring together with a nitrogen atom. The nitrogen-containing heterocycle formed by —NAr ₁ Ar ₂ or —NAr ₃ Ar ₄ is substituted or unsubstituted —N-carbazoyl, substituted or unsubstituted —N-phenoxadiyl, or substituted or unsubstituted —N -Preferable is phenothiadiyl.

—NAr ₁ Ar ₂ or —NAr ₃ Ar ₄ is unsubstituted or a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms. -N-carbazoyl group, -N-phenoxadiyl group, or -N-phenothiadiyl group, which is mono-substituted or poly-substituted by, and the like; preferably unsubstituted, halogen atom, carbon number 1 -N-carbazoyl group, -N-phenoxadiyl group, monosubstituted or polysubstituted with -4 alkyl group, C1-C4 alkoxy group, C6-C10 aryl group, or the like, or -N-phenothiadiyl group is more preferred; unsubstituted -N-carbazoyl group, unsubstituted -N-phenoxadiyl group, or unsubstituted -N- More preferably from Enochiajiiru group is preferably Among them, N- carbazolyl group.

Specific examples of the nitrogen-containing heterocyclic group represented by —NAr ₁ Ar ₂ or —NAr ₃ Ar ₄ include —N-carbazoyl group, 2-methyl-N-carbazoyl group, 3-methyl-N-carbazoyl group, 4 -Methyl-N-carbazoyl group, 3-n-butyl-N-carbazoyl group, 3-n-hexyl-N-carbazoyl group, 3-n-octyl-N-carbazoyl group, 3-n-decyl-N-carbazoyl group A group, 3,6-dimethyl-N-carbazoyl group, 2-methoxy-N-carbazoyl group, 3-methoxy-N-carbazoyl group, 3-ethoxy-N-carbazoyl group, 3-isopropoxy-N-carbazoyl group, 3-n-butoxy-N-carbazoyl group, 3-n-octyloxy-N-carbazoyl group, 3-n-decyloxy-N-carbazoyl group, 3-phenyl-N-carbazoyl group, 3- (4'-methyl) Phenyl) -N-carbazoyl group, 3- (4′-tert-butyl) Eniru) -N- carbazoyl group, 3-chloro -N- carbazoyl group, -N- phenoxazyl group, -N- phenothiazyl group, and the like 2-methyl -N- phenothiazyl group.

R ₁ and R ₂ in the general formula (1) represent a hydrogen atom, a linear, branched or cyclic alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group.

R ₁ and R ₂ are a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 16 carbon atoms, a substituted or unsubstituted aryl group having 4 to 16 carbon atoms, or a substituted or unsubstituted group having 5 to 16 carbon atoms. It is preferably a substituted aralkyl group; a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms, a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, or a 7 to 12 carbon atom. It is more preferably a substituted or unsubstituted aralkyl group; a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms, a carbocyclic aromatic group having 6 to 10 carbon atoms, or a 7 to 10 carbon atom. More preferred is a carbocyclic aralkyl group.

Specific examples of the substituted or unsubstituted aryl group represented by R ₁ and R ₂ in the general formula (1) are the same substituted or unsubstituted aryl groups as the specific examples of Ar _{1 to} Ar ₄ .
Specific examples of the alkyl group for R ₁ and R ₂ include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, and n-pentyl group. , Isopentyl group, neopentyl group, tert-pentyl group, cyclopentyl group, n-hexyl group, 2-ethylbutyl group, 3,3-dimethylbutyl group, cyclohexyl group, n-heptyl group, cyclohexylmethyl group, n-octyl group, Examples include, but are not limited to, tert-octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group, n-dodecyl group, n-tetradecyl group, n-hexadecyl group and the like.

Specific examples of the aralkyl group of R ₁ and R ₂ include benzyl group, phenethyl group, α-methylbenzyl group, α, α-dimethylbenzyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, furfuryl group, 2 -Methylbenzyl group, 3-methylbenzyl group, 4-methylbenzyl group, 4-ethylbenzyl group, 4-isopropylbenzyl group, 4-tert-butylbenzyl group, 4-n-hexylbenzyl group, 4-nonylbenzyl group 3,4-dimethylbenzyl group, 3-methoxybenzyl group, 4-methoxybenzyl group, 4-ethoxybenzyl group, 4-n-butoxybenzyl group, 4-n-hexyloxybenzyl group, 4-nonyloxybenzyl group Examples include, but are not limited to, a 4-fluorobenzyl group, a 3-fluorobenzyl group, a 2-chlorobenzyl group, and a 4-chlorobenzyl group.

Z ₁ and Z ₂ in the general formula (1) represent a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group, a linear, branched or cyclic alkoxy group, or a substituted or unsubstituted aryl group.

Z ₁ and Z ₂ are a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group having 1 to 16 carbon atoms, a linear, branched or cyclic alkoxy group having 1 to 16 carbon atoms, or a carbon number of 4 to It is preferably a 20-substituted or unsubstituted aryl group; a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms, a linear, branched or cyclic group having 1 to 8 carbon atoms More preferably, it is an alkoxy group or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms; and more preferably a hydrogen atom.

Specific examples of the linear, branched or cyclic alkyl group of Z ₁ and Z ₂ are the same linear, branched or cyclic alkyl groups as the specific examples of R ₁ and R ₂ . Specific examples of the substituted or unsubstituted aryl group for Z ₁ and Z ₂ are the same substituted or unsubstituted aryl groups as the specific examples for Ar _{1 to} Ar ₄ .

Examples of the halogen atom for Z ₁ and Z ₂ include a fluorine atom, a chlorine atom, a bromine atom and the like.

Specific examples of the alkoxy group of Z ₁ and Z ₂ include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, sec-butoxy group, n-pentyloxy group, isopentyl. Oxy group, neopentyloxy group, cyclopentyloxy group, n-hexyloxy group, 2-ethylbutoxy group, 3,3-dimethylbutoxy group, cyclohexyloxy group, n-heptyloxy group, cyclohexylmethyloxy group, n-octyl Examples include an oxy group, 2-ethylhexyloxy group, n-nonyloxy group, n-decyloxy group, n-dodecyloxy group, n-tetradecyloxy group, n-hexadecyloxy group and the like.

X ₁ and X ₂ in the general formula (1) represent a substituted or unsubstituted arylene group. The arylene group is preferably the general formula (2).
_{- (A 1 -X 11) m} -A 2 - (2)

A ₁ and A ₂ in formula (2) represent a substituted or unsubstituted phenylene group, a substituted or unsubstituted naphthylene group, or a substituted or unsubstituted fluorene-diyl group.
A ₁ and A ₂ preferably represent a substituted or unsubstituted phenylene group.

A ₁ and A ₂ are more preferably a substituted or unsubstituted 1,3-phenylene group or a substituted or unsubstituted 1,4-phenylene group.

X ₁₁ in the general formula (2) represents a single bond, an oxygen atom or a sulfur atom.

M in the general formula (2) represents 0 or 1. In the general formula (2), when m represents ₁ , A ₁ is more preferably a substituted or unsubstituted 1,4-phenylene group.

More preferable examples of X ₁ and X ₂ in the compound represented by the general formula (1) include an arylene group represented by the general formula (2-a) to the general formula (2-h).

Z ₁₁ and Z ₁₂ in formula (2-a) represent a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group, a linear, branched or cyclic alkoxy group, or a substituted or unsubstituted aryl group. .

Z ₂₁ and Z ₂₂ in formula (2-b) represent a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group, a linear, branched or cyclic alkoxy group, or a substituted or unsubstituted aryl group. .

Z ₃₁ and Z ₃₂ in formula (2-c) represent a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group, a linear, branched or cyclic alkoxy group, or a substituted or unsubstituted aryl group. .

Z ₄₁ and Z ₄₂ in formula (2-d) represent a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group, a linear, branched or cyclic alkoxy group, or a substituted or unsubstituted aryl group. .

Z ₅₁ and Z ₅₂ in formula (2-e) represent a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group, a linear, branched or cyclic alkoxy group, or a substituted or unsubstituted aryl group. .

Z ₆₁ and Z ₆₂ in formula (2-f) represent a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group, a linear, branched or cyclic alkoxy group, or a substituted or unsubstituted aryl group. . R ₁₁ and R ₁₂ in the formula (2-f) represent a hydrogen atom, a linear, branched or cyclic alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group.

Z ₇₁ and Z ₇₂ in formula (2-g) represent a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group, a linear, branched or cyclic alkoxy group, or a substituted or unsubstituted aryl group. .

Z ₈₁ and Z ₈₂ in formula (2-h) represent a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group, a linear, branched or cyclic alkoxy group, or a substituted or unsubstituted aryl group. .

In formula (2-a) ~ the general formula _{(2-h), Z 11} , Z 12, Z 21, Z 22, Z 31, Z 32, Z 41, Z 42, Z 51, Z 52, Z 61, Z ₆₂ , Z ₇₁ , Z ₇₂ , Z ₈₁ and Z ₈₂ (hereinafter collectively referred to as “Z _{11 to} Z ₈₂ ”) are a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group, It represents a chain, branched or cyclic alkoxy group, or a substituted or unsubstituted aryl group.

Z _{11 to} Z ₈₂ are a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group having 1 to 16 carbon atoms, a linear, branched or cyclic alkoxy group having 1 to 16 carbon atoms, or a carbon number of 4 to It is preferably a 20-substituted or unsubstituted aryl group; a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms, a linear, branched or cyclic group having 1 to 8 carbon atoms More preferably, it is an alkoxy group or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms; and more preferably a hydrogen atom.

Specific examples of the linear, branched or cyclic alkyl group of Z _{11 to} Z ₈₂ are, for example, the same linear, branched or cyclic alkyl group as the specific examples of R ₁ and R ₂ . Specific examples of the substituted or unsubstituted aryl group of Z _{11 to} Z ₈₂ are, for example, the same substituted or unsubstituted aryl group as the specific examples of Ar _{1 to} Ar ₄ .

Examples of the halogen atoms of Z _{11 to} Z ₈₂ include a fluorine atom, a chlorine atom, a bromine atom and the like. Specific examples of the linear, branched or cyclic alkoxy group of Z _{11 to} Z ₈₂ include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, sec-butoxy group, n -Pentyloxy group, isopentyloxy group, neopentyloxy group, cyclopentyloxy group, n-hexyloxy group, 2-ethylbutoxy group, 3,3-dimethylbutoxy group, cyclohexyloxy group, n-heptyloxy group, cyclohexyl Examples include methyloxy group, n-octyloxy group, 2-ethylhexyloxy group, n-nonyloxy group, n-decyloxy group, n-dodecyloxy group, n-tetradecyloxy group, n-hexadecyloxy group and the like.

R ₁₁ and R ₁₂ in the general formula (2-f) are each a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 16 carbon atoms, a substituted or unsubstituted aryl group having 4 to 16 carbon atoms, or carbon A substituted or unsubstituted aralkyl group having 5 to 16 carbon atoms is preferable; a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 12 carbon atoms Or a substituted or unsubstituted aralkyl group having 7 to 12 carbon atoms; a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms, or a carbocyclic aromatic group having 6 to 10 carbon atoms. Or a carbocyclic aralkyl group having 7 to 10 carbon atoms is more preferable.

Specific examples of the substituted or unsubstituted aryl group for R ₁₁ and R ₁₂ are, for example, the same substituted or unsubstituted aryl group as the specific examples for Ar _{1 to} Ar ₄ . Specific examples of the linear, branched or cyclic alkyl group of R ₁₁ and R ₁₂ are, for example, the same substituted or unsubstituted alkyl groups as the specific examples of R ₁ and R ₂ . Specific examples of the substituted or unsubstituted aralkyl group for R ₁₁ and R ₁₂ are the same substituted or unsubstituted aralkyl groups as the specific examples for R ₁ and R ₂ .
In the general formula (1), X is more preferably (2-a), (2-e), (2-g) and (2-h), more preferably (2-a), ( 2-g) and (2-h).

  Specific examples of the compound represented by the general formula (1) include the following compounds, but are not limited thereto. In the formula, Ph represents a phenyl group, and Bz represents a benzyl group.

  The compound represented by the general formula (1) can be produced by a known method. For example, reference can be made to JP-A-11-224779. For example, the compound represented by the general formula (3), the compound represented by the general formula (4), and the compound represented by the general formula (5) are subjected to a coupling reaction to thereby generate a compound represented by the general formula (1). ) Can be produced.

Y _{1 to} Y ₄ in the formulas (3) to (5) represent a halogen atom, and Ar _{1 to} Ar ₄ , R ₁ , R ₂ , Z ₁ , Z _2, and X ₁ and X ₂ are represented by the general formula (1) Defined in the same way as that.

  As described above, the organic electroluminescent element has a pair of electrodes and a functional layer sandwiched between the electrode pairs. The functional layer includes at least a light emitting layer, and may further include a hole injection transport layer, an electron injection transport layer, and the like.

  For each component of the organic electroluminescent element, an (EL-1) type element having the substrate 1 / anode 2 / hole injection transport layer 3 / light emitting layer 4 / electron injection transport layer 5 / cathode 6 shown in FIG. Will be described with reference to FIG. In FIG. 1, reference numeral 7 denotes a power source.

  The organic electroluminescent element of the present invention is preferably supported on the substrate 1. The substrate is preferably transparent or translucent. Examples of the material of the substrate include glass such as soda lime glass and borosilicate glass, and transparent polymers such as polyester, polycarbonate, polysulfone, polyethersulfone, polyacrylate, polymethylmethacrylate, polypropylene, and polyethylene.

  The substrate may be a substrate made of a translucent plastic sheet, quartz, transparent ceramics, or a composite sheet combining these. Furthermore, for example, a color filter film, a color conversion film, and a dielectric reflection film can be combined with the substrate to control the emission color.

The electrode material of the anode 2 is preferably a metal, alloy or conductive compound having a relatively large work function. Examples of the electrode material of the anode 2 include gold, platinum, silver, copper, cobalt, nickel, palladium, vanadium, tungsten, indium oxide (In ₂ O ₃ ), tin oxide (SnO ₂ ), zinc oxide, and ITO (indium). -Tin oxide (Indium Tin Oxide), polythiophene, polypyrrole, etc. are included. These electrode materials may be used alone or in combination.

  Further, the anode may have a single layer structure or a multilayer structure. The sheet electrical resistance of the anode is preferably set to several hundred Ω / □ or less, more preferably about 5 to 50 Ω / □. The thickness of the anode is generally about 5 to 1000 nm, preferably about 10 to 500 nm, although it depends on the material of the electrode material used.

  The anode 2 can be formed on the substrate by an electrode material such as a vapor deposition method or a sputtering method.

  The hole injection / transport layer 3 has a function of facilitating injection of holes from the anode and a function of transporting the injected holes. The hole injecting and transporting layer 3 of the electroluminescent element of the present invention contains a compound represented by the general formula (1) and / or another compound having a hole injecting and transporting function. Examples of compounds having other hole injecting and transporting functions include phthalocyanine derivatives, triarylamine derivatives, triarylmethane derivatives, oxazole derivatives, hydrazone derivatives, stilbene derivatives, pyrazoline derivatives, polysilane derivatives, polyphenylene vinylene and its derivatives, polythiophene And derivatives thereof, poly-N-vinylcarbazole and the like. The compounds having a hole injecting and transporting function may be used alone or in combination.

  Specific examples of the compound having a hole injecting and transporting function other than the compound represented by the general formula (1) include triarylamine derivatives, polythiophene and derivatives thereof, and poly-N-vinylcarbazole and derivatives thereof.

  Examples of triarylamine derivatives include 4,4′-bis [N-phenyl-N- (4 ″ -methylphenyl) amino] -1,1′-biphenyl, 4,4′-bis [N-phenyl]. -N- (3 ″ -methylphenyl) amino] -1,1′-biphenyl, 4,4′-bis [N-phenyl-N- (3 ″ -methoxyphenyl) amino] -1,1′- Biphenyl, 4,4′-bis [N-phenyl-N- (1 ″ -naphthyl) amino] -1,1′-biphenyl, 3,3′-dimethyl-4,4′-bis [N-phenyl- N- (3 ″ -methylphenyl) amino] -1,1′-biphenyl, 1,1-bis [4 ′-[N, N-di (4 ″ -methylphenyl) amino] phenyl] cyclohexane, 9 , 10-Bis [N- (4′-methylphenyl) -N- (4 ″ -n-butylphenyl) amino] phenanthrene, 3,8-bis (N, N-diphenylamino) -6-phenylphenanthate Lysine, 4-me Tyl-N, N-bis [4 ″, 4 ′ ″-bis [N ′, N′-di (4-methylphenyl) amino] biphenyl-4-yl] aniline, N, N′-bis [4 -(Diphenylamino) phenyl] -N, N'-diphenyl-1,3-diaminobenzene, N, N'-bis [4- (diphenylamino) phenyl] -N, N'-diphenyl-1,4-diamino Benzene, 5,5 ″ -bis [4- (bis [4-methylphenyl] amino] phenyl-2,2 ′: 5 ′, 2 ″ -terthiophene, 1,3,5-tris (diphenylamino) Benzene, 4,4 ′, 4 ″ -tris (N-carbazolyl) triphenylamine, 4,4 ′, 4 ″ -tris [N, N-bis (4 ′ ″-tert-butylbiphenyl-4 ′) '' '-Yl) amino] triphenylamine, 1,3,5-tris [N- (4'-diphenylamino] benzene and the like.

  When the compound represented by the general formula (1) and another compound having a hole injection function are used in combination, the content of the compound represented by the general formula (1) in the hole injection transport layer is 0.1 wt% or more, preferably 0.5 to 99.9 wt%, more preferably 3 to 97 wt%.

  The light emitting layer 4 is a layer containing a compound having a function of injecting holes and electrons, a function of transporting them, and a function of generating excitons by recombination of holes and electrons.

  The light emitting layer contains at least one of the above phosphorescent materials (compounds having a phosphorescent function). Furthermore, a light emitting layer contains either or both of the compound represented by General formula (1), or the compound which has light emission functions other than the compound represented by General formula (1). It is preferable that the light emitting layer of the organic electroluminescent element of this invention contains the compound represented by General formula (1).

  In the light emitting layer, the phosphorescent light emitting material functions as a dopant material (or guest material). On the other hand, a compound having a light emitting function other than the compound represented by the general formula (1) and / or the compound represented by the general formula (1) functions as a host material.

  Examples of compounds having a light emitting function other than the compound represented by the general formula (1) include triarylamine derivatives, organometallic complexes, benzothiazole derivatives, benzoxazole derivatives, benzimidazole derivatives, pyrazine derivatives, and cinnamic acid esters. Derivatives, poly-N-vinylcarbazole and derivatives thereof, polythiophene and derivatives thereof, polyphenylene and derivatives thereof, polyfluorene and derivatives thereof, polyphenylene vinylene and derivatives thereof, polybiphenylene vinylene and derivatives thereof, polyterphenylene vinylene and derivatives thereof, poly Examples include naphthylene vinylene and its derivatives, polythienylene vinylene and its derivatives, and the like.

  The compound having a light emitting function other than the compound represented by the general formula (1) is preferably a triarylamine derivative or an organometallic complex. Examples of the triarylamine derivative include the compounds exemplified as the compound having a hole injecting and transporting function. Examples of organometallic agents include tris (8-quinolinolato) aluminum, bis (10-benzo [h] quinolinolato) beryllium, zinc salt of 2- (2′-hydroxyphenyl) benzothiazole.

  When both the compound represented by the general formula (1) and the compound having a light emitting function other than the compound represented by the general formula (1) are contained in the light emitting layer of the organic electroluminescent element, both The ratio of the compound represented by the general formula (1) to the total of the compounds is preferably 60 to 99.999% by weight.

  An electron injecting and transporting layer is formed on the cathode side of the light emitting layer of the organic electroluminescent device of the present invention. The electron injecting and transporting layer may be formed adjacent to the light emitting layer, or an electron transporting layer (hole blocking layer) may be formed between the light emitting layer and the electron injecting and transporting layer.

  The hole blocking layer efficiently accumulates holes injected into the light emitting layer in the light emitting layer. Thereby, the establishment of the recombination of holes and electrons is improved, and high efficiency of light emission is achieved. The hole blocking layer includes, for example, a phentroline derivative, a triazole derivative, bis (2-methylquinolinolato) (4-phenylphenolate) aluminum, and the like.

  The electron injection / transport layer 5 is a layer containing a compound having a function of facilitating injection of electrons from the cathode and / or a function of transporting injected electrons.

  The electron injecting and transporting layer of the organic electroluminescence device of the present invention may contain the compound of the general formula (1) or may contain other compounds having an electron injecting and transporting function. Examples of other compounds having an electron injecting and transporting function include organometallic complexes, oxadiazole derivatives, triazole derivatives, triazine derivatives, perylene derivatives, quinoline derivatives, quinoxaline derivatives, diphenylquinone derivatives, nitro-substituted fluorenone derivatives, thiopyrandi. Oxide derivatives and the like are included. The electron injecting and transporting layer may contain one type of compound having an electron injecting function, or may contain a plurality of types.

  Examples of organometallic complexes include organoaluminum complexes such as tris (8-quinolinolato) aluminum, organoberyllium complexes such as bis (10-benzo [h] quinolinolato) beryllium, beryllium salts of 5-hydroxyflavone, 5-hydroxyflavone Of aluminum salts.

  The electron injecting and transporting layer preferably contains a compound represented by the general formula (1) or an organoaluminum complex. Here, the organoaluminum complex is an organoaluminum complex having a substituted or unsubstituted 8-quinolinolato ligand. Examples of the organoaluminum complex having a substituted or unsubstituted 8-quinolylate ligand include compounds represented by general formula (a) to general formula (c).

(Q) ₃ -Al (a)
(Q in formula (a) represents a substituted or unsubstituted 8-quinolinolato ligand)
(Q) ₂ -Al-OL- (b)
(Q in the formula (b) represents a substituted or unsubstituted 8-quinolinolate ligand, OL ′ represents a phenolate ligand, and L ′ represents a hydrocarbon having 6 to 24 carbon atoms having a phenyl group. Represents a group)
(Q) ₂ -Al-O-Al- (Q) ₂ (c)
(Q in the formula (c) represents a substituted or unsubstituted 8-quinolinolato ligand)

  Specific examples of organoaluminum complexes having a substituted or unsubstituted 8-quinolinolato ligand contained in the electron injecting and transporting layer include tris (8-quinolinolato) aluminum, tris (4-methyl-8-quinolinolato) aluminum, tris. (5-methyl-8-quinolinolato) aluminum, tris (3,4-dimethyl-8-quinolinolato) aluminum, tris (4,5-dimethyl-8-quinolinolato) aluminum, tris (4,6-dimethyl-8-quinolinolato) ) Aluminum, bis (2-methyl-8-quinolinolato) (phenolate) aluminum, bis (2-methyl-8-quinolinolato) (2-methylphenolate) aluminum, bis (2-methyl-8-quinolinolato) (3- Methylphenolate) aluminum, bis (2-methyl-8-quinolinolato) (4-methyl) Enolate) aluminum, bis (2-methyl-8-quinolinolato) (2-phenylphenolate) aluminum, bis (2-methyl-8-quinolinolato) (3-phenylphenolato) aluminum, bis (2-methyl-8- Quinolinolate) (4-phenylphenolate) aluminum, bis (2-methyl-8-quinolinolato) (2,3-dimethylphenolate) aluminum, bis (2-methyl-8-quinolinolato) (2,6-dimethylphenolate) ) Aluminum, bis (2-methyl-8-quinolinolato) (3,4-dimethylphenolate) aluminum, bis (2-methyl-8-quinolinolato) (3,5-dimethylphenolato) aluminum, bis (2-methyl) -8-quinolinolato) (3,5-di-tert-butylphenolate) aluminum, bis (2-methyl-8-quinolinate) Lat) (2,6-diphenylphenolate) aluminum, bis (2-methyl-8-quinolinolato) (2,4,6-triphenylphenolate) aluminum, bis (2-methyl-8-quinolinolato) (2, 4,6-trimethylphenolate) aluminum, bis (2-methyl-8-quinolinolato) (2,4,5,6-tetramethylphenolate) aluminum, bis (2-methyl-8-quinolinolato) (1-naphtholate) ) Aluminum, bis (2-methyl-8-quinolinolato) (2-naphtholato) aluminum, bis (2,4-dimethyl-8-quinolinolato) (2-phenylphenolato) aluminum, bis (2,4-dimethyl-8 -Quinolinolate) (3-phenylphenolate) aluminum, bis (2,4-dimethyl-8-quinolinolato) (4-phenylphenolate) a Minium, bis (2,4-dimethyl-8-quinolinolato) (3,5-dimethylphenolate) aluminum, bis (2,4-dimethyl-8-quinolinolato) (3,5-di-tert-butylphenolate) Aluminum, bis (2-methyl-8-quinolinolato) aluminum-μ-oxo-bis (2-methyl-8-quinolinolato) aluminum, bis (2,4-dimethyl-8-quinolinolato) aluminum-μ-oxo-bis ( 2,4-dimethyl-8-quinolinolato) aluminum, bis (2-methyl-4-ethyl-8-quinolinolato) aluminum-μ-oxo-bis (2-methyl-4-ethyl-8-quinolinolato) aluminum, bis ( 2-Methyl-4-methoxy-8-quinolinolato) aluminum-μ-oxo-bis (2-methyl-4-methoxy-8-quinolinolato) aluminum, bis (2-methyl-5-sia) -8-quinolinolato) aluminum-μ-oxo-bis (2-methyl-5-cyano-8-quinolinolato) aluminum, bis (2-methyl-5-trifluoromethyl-8-quinolinolato) aluminum-μ-oxo-bis (2-methyl-5-trifluoromethyl-8-quinolinolato) aluminum and the like are included.

  The electrode material of the cathode 6 is preferably a metal, alloy or conductive compound having a relatively small work function. Examples of the electrode material of the cathode 6 include lithium, lithium-indium alloy, lithium fluoride, organic acid lithium salt (lithium benzoate, lithium acetate, etc.), sodium, sodium-potassium alloy, calcium, magnesium, magnesium-silver alloy. , Magnesium-indium alloy, indium, ruthenium, titanium, manganese, yttrium, aluminum, aluminum-lithium alloy, aluminum-calcium alloy, aluminum-magnesium alloy, graphite thin and the like. These electrode materials may be used alone or in combination.

  The cathode may have a single layer structure or a multilayer structure. The sheet electrical resistance of the cathode is preferably several hundred Ω / □ or less. Although the thickness of a cathode is based also on the electrode material to be used, it is 5-1000 nm normally, Preferably it is 10-500 nm. In order to efficiently extract light emitted from the organic electroluminescence device, at least one of the anode and the cathode is preferably transparent or translucent. It is preferable to set the electrode material and the electrode thickness so that the transmittance of the emitted light of the anode or the cathode is 70% or more.

  The cathode can be produced by forming a layer of these electrode materials on the electron injecting and transporting layer by vapor deposition, sputtering, ion vapor deposition, ion plating, cluster ion beam, or the like.

  The hole injecting and transporting layer, the light emitting layer or the electron injecting and transporting layer can be formed by vacuum deposition, ionization deposition, solution coating (for example, spin coating, casting, dip coating, bar coating, roll coating, Langmuir However, the present invention is not particularly limited to these means.

When forming each layer such as a hole injecting and transporting layer, a light emitting layer, and an electron injecting and transporting layer by a vacuum deposition method, the conditions for vacuum deposition are usually a boat temperature (deposition source temperature) under a vacuum of about 10 ⁻³ Pa or less. ) Is preferably about 50 to 500 ° C., the substrate temperature is about −50 to 300 ° C., and the deposition rate is about 0.005 to 50 nm / sec, but is not particularly limited.

  When forming each layer such as a hole injecting and transporting layer, a light emitting layer, and an electron injecting and transporting layer by a vacuum deposition method, it is preferable to form each layer continuously under vacuum. It becomes possible to manufacture an organic electroluminescent element excellent in various characteristics by forming continuously. When each layer such as a hole injection transport layer, a light emitting layer, an electron injection transport layer, etc. is formed by vacuum deposition using a plurality of compounds, each boat containing the compounds is individually temperature controlled and deposited. Is preferred.

  When each layer is formed by a solution coating method, the components for forming each layer and, if necessary, a binder resin or the like are dissolved or dispersed in a solvent to obtain a coating solution.

  The solvent may be an organic solvent or water. Examples of organic solvents include hydrocarbon solvents such as hexane, octane, decane, toluene, xylene, ethylbenzene and 1-methylnaphthalene; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; dichloromethane, chloroform, tetra Halogenated hydrocarbon solvents such as chloromethane, dichloroethane, trichloroethane, tetrachloroethane, chlorobenzene, dichlorobenzene, and chlorotoluene; ester solvents such as ethyl acetate, butyl acetate, amyl acetate, and ethyl lactate; methanol, propanol, butanol, pen Alcohol solvents such as butanol, hexanol, cyclohexanol, methyl cellosolve, ethyl cellosolve, ethylene glycol; dibutyl ether, tetrahydrofuran, Ether solvents such as dioxane, dimethoxyethane, anisole; N, N-dimethylformamide, N, N-dimethylacetamide, 1-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, dimethyl sulfoxide, etc. A polar solvent is included. A solvent may be used independently and may be used together.

  In order to disperse the components of the hole injecting and transporting layer, the light emitting layer, and the electron injecting and transporting layer in the solvent, use a ball mill, a sand mill, a paint shaker, an attritor, a homogenizer, or the like to disperse each component into fine particles. be able to.

  Examples of the binder resin contained in the coating solution used in the solution coating method include poly-N-vinylcarbazole, polyarylate, polystyrene, polyester, polysiloxane, polymethyl methacrylate, polymethyl acrylate, polyether, polycarbonate, polyamide, Polyimide, polyamideimide, polyparaxylene, polyethylene, polyphenylene oxide, polyethersulfone, polyaniline and derivatives thereof, polythiophene and derivatives thereof, polyphenylene vinylene and derivatives thereof, polyfluorene and derivatives thereof, polythienylene vinylene and derivatives thereof, etc. Molecular compounds are included. Binder resins may be used alone or in combination.

The solid component concentration of the coating solution is not particularly limited, and is set to a concentration range suitable for obtaining a desired thickness. Usually, it is 0.1 to 50% by weight, preferably 1 to 30% by weight.
When using binder resin, the content in a coating liquid is not specifically limited. The content of the binder resin with respect to the total of the components forming each layer such as the hole injecting and transporting layer, the light emitting layer, and the electron injecting and transporting layer is usually 5 to 99.9% by weight, preferably 10 to 99% by weight. is there.

  The film thickness of each layer such as the hole injecting and transporting layer, the light emitting layer, and the electron injecting and transporting layer is not particularly limited, but is usually 5 nm to 5 μm.

  The organic electroluminescent element preferably has a protective layer (sealing layer) for the purpose of preventing intrusion of oxygen, moisture and the like. The material of the protective layer is an organic polymer material or an inorganic material. Examples of organic polymer materials include fluorine resin, epoxy resin, silicone resin, epoxy silicone resin, polystyrene, polyester, polycarbonate, polyamide, polyimide, polyamideimide, polyparaxylene, polyethylene, polyphenylene oxide, etc., photocuring Resin may be used. Examples of the inorganic material include diamond thin film, amorphous silica, electrically insulating glass, metal oxide, metal nitride, metal carbide, metal sulfide and the like. The material used for the protective layer may be used alone or in combination. The protective layer may have a single layer structure or a multilayer structure.

  The organic electroluminescent element may be protected by being enclosed in an inert material. Examples of the inert substance include paraffin, liquid paraffin, silicon oil, fluorocarbon oil, zeolite-containing fluorocarbon oil, and the like.

  A metal oxide film (for example, an aluminum oxide film) or a metal fluoride film may be provided as a protective film on the electrode of the organic electroluminescent element.

  An interface layer (intermediate layer) may be provided on the surface of the anode of the organic electroluminescent element. Examples of the material for the interface layer include organophosphorus compounds, polysilanes, aromatic amine derivatives, phthalocyanine derivatives, and the like. Further, the surface of the electrode (eg anode) may be treated with acid, ammonia / hydrogen peroxide, or plasma.

  The organic electroluminescent element can be usually used as a direct current drive type element, but may be used as an alternating current drive type element. Further, the organic electroluminescence device of the present invention may be a segment type, a passive drive type such as a simple matrix drive type, or an active drive type such as a TFT (thin film transistor) type or an MIM (metal-insulator-metal) type. It may be. The driving voltage is usually 2 to 30V. Organic electroluminescent elements include panel-type light sources (for example, backlights for watches, liquid crystal panels, etc.), various light-emitting elements (for example, alternatives to light-emitting elements such as LEDs), lighting devices (planar lighting, special lighting, etc.), various types Display elements [for example, information display elements (personal computer monitors, mobile phone / mobile terminal display elements)], various signs, various sensors, and the like.

[Example 1]
A glass substrate having an ITO transparent electrode (anode) having a thickness of 150 nm was subjected to ultrasonic cleaning using a neutral detergent, Semicoclean (manufactured by Furuuchi Chemical), ultrapure water, acetone, and isopropanol. The substrate was dried with nitrogen gas, further UV / ozone cleaned, fixed to the substrate holder of the vapor deposition apparatus, and the vapor deposition tank was depressurized to 1 × 10 ⁻⁵ Pa.

  First, bis [N-phenyl-N- (1-naphthyl)]-4,4′-diamino-1,1′-biphenyl was deposited on the ITO transparent electrode at a deposition rate of 0.1 nm / sec. A hole injection layer was provided.

  Next, 1,3-bis (N-carbazolyl) benzene (hereinafter abbreviated as m-CP) was deposited at a deposition rate of 0.1 nm / sec and deposited on the hole injection layer to a thickness of 10 nm. A hole transport layer was provided.

The exemplary compound A-1 and a tris (phenylpyridyl) iridium complex [hereinafter abbreviated as Ir (ppy) ₃ ], which is a phosphorescent material represented by the formula (a1-1), are each deposited at a deposition rate of 0.2 nm / sec. The light emitting layer having a film thickness of 25 nm was formed by vapor deposition on the hole transport layer at 0.016 nm / sec.

  Further, 4,7-diphenyl-1,10-phenanthroline (hereinafter abbreviated as BPhen) is vapor-deposited on the light-emitting layer at a vapor deposition rate of 0.1 nm / sec to form a 15 nm-thick hole blocking layer (electron). Transport layer) was provided.

  Further, tris (8-quinolinolato) aluminum was deposited on the hole blocking layer at a deposition rate of 0.1 nm / sec to provide an electron transport layer having a thickness of 25 nm. The substrate temperature during vapor deposition was room temperature.

  Subsequently, lithium fluoride was deposited to a thickness of 0.5 nm at a deposition rate of 0.02 nm / sec. Finally, aluminum was deposited as a cathode to a thickness of 100 nm at a deposition rate of 2.0 nm / sec to produce an organic electroluminescent device. Vapor deposition was carried out while maintaining the vacuum state of the vapor deposition tank.

A DC voltage was applied to the produced organic electroluminescence device, and the organic electroluminescence device was continuously driven at a constant current density of 10 mA / cm ^{2 in} a dry atmosphere at room temperature. Initially, the voltage value was 6.1 V, and green light emission with a luminance of 2600 cd / m ² was confirmed. The half life of luminance was 4200 hours.

[Comparative Example 1]
In Example 1, instead of using the compound of Illustrative Compound A-1 in forming the light emitting layer, the same procedure as described in Example 1 was performed except that the light emitting layer was formed using the following compound (CBP). In addition, an organic electroluminescent element was produced.

A DC voltage was applied to the produced organic electroluminescence device, and the organic electroluminescence device was continuously driven at a constant current density of 10 mA / cm ^{2 in} a dry atmosphere at room temperature. Initially, the voltage value was 6.2 V, and green light emission with a luminance of 1800 cd / m ² was confirmed. The half life of luminance was 600 hours.

[Example 2]
In Example 1, instead of using the compound of Exemplified Compound A-1, an organic electric field was obtained in the same manner as in the operation described in Example 1 except that the light emitting layer was formed using the compound of Exemplified Compound A-8. A light emitting element was manufactured.

A DC voltage was applied to the produced organic electroluminescence device, and the organic electroluminescence device was continuously driven at a constant current density of 10 mA / cm ^{2 in} a dry atmosphere at room temperature. Initially, the voltage value was 6.2 V, and green light emission with a luminance of 2600 cd / m ² was confirmed. The luminance half-life was 4400 hours.

[Comparative Example 2]
In Example 1, the following 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (α-NPD) was used instead of using the compound of Illustrative Compound A-1 in forming the light emitting layer. ) Was used to produce an organic electroluminescent element in the same manner as in the operation described in Example 1 except that the light emitting layer was formed.

A DC voltage was applied to the produced organic electroluminescence device, and the organic electroluminescence device was continuously driven at a constant current density of 10 mA / cm ^{2 in} a dry atmosphere at room temperature. Initially, the voltage value was 6.1 V, and green light emission with a luminance of 900 cd / m ² was confirmed. The half life of the brightness was 120 hours.

[Example 3]
In Example 1, instead of using the compound of Exemplified Compound A-1, an organic electric field was obtained in the same manner as in the operation described in Example 1 except that the light emitting layer was formed using the compound of Exemplified Compound A-11. A light emitting element was manufactured.

A DC voltage was applied to the produced organic electroluminescence device, and the organic electroluminescence device was continuously driven at a constant current density of 10 mA / cm ^{2 in} a dry atmosphere at room temperature. Initially, the voltage value was 6.3 V, and green light emission with a luminance of 2400 cd / m ² was confirmed. The half life of luminance was 4100 hours.

[Example 4]
In Example 1, instead of using the compound of Exemplified Compound A-1, an organic electric field was obtained in the same manner as in the operation described in Example 1 except that the light emitting layer was formed using the compound of Exemplified Compound A-17. A light emitting element was manufactured.

A DC voltage was applied to the produced organic electroluminescence device, and the organic electroluminescence device was continuously driven at a constant current density of 10 mA / cm ^{2 in} a dry atmosphere at room temperature. Initially, the voltage value was 6.4 V, and green light emission with a luminance of 2600 cd / m ² was confirmed. The half life of luminance was 4800 hours.

[Example 5]
A glass substrate having an ITO transparent electrode (anode) having a thickness of 150 nm was subjected to ultrasonic cleaning using a neutral detergent, Semicoclean (manufactured by Furuuchi Chemical), ultrapure water, acetone, and isopropanol. The substrate was dried with nitrogen gas and further UV / ozone cleaned. The cleaned substrate was fixed to the substrate holder of the vapor deposition apparatus, and the vapor deposition tank was depressurized to 1 × 10 ⁻⁵ Pa.

  First, copper phthalocyanine was deposited on the ITO transparent electrode at a deposition rate of 0.1 nm / sec to form a 10 nm-thick hole injection layer. Further, bis [N-phenyl-N- (1-naphthyl)]-4,4′-diamino-1,1′-biphenyl was deposited at a deposition rate of 0.1 nm / sec, and a hole injection layer having a thickness of 30 nm was formed. Provided.

  Next, m-CP was deposited at a deposition rate of 0.1 nm / sec to provide a 10 nm-thick hole transport layer.

  Exemplified Compound A-18 and an iridium complex which is a phosphorescent material represented by the above formula (a1-13) were deposited on the hole transport layer at a deposition rate of 0.2 nm / sec and 0.016 nm / sec, respectively. A light emitting layer having a thickness of 25 nm was provided.

  Further, BPhen was deposited on the light emitting layer at a deposition rate of 0.1 nm / sec to provide a hole blocking layer (electron transport layer) having a thickness of 15 nm.

  Further, tris (8-quinolinolato) aluminum was deposited on the hole blocking layer at a deposition rate of 0.1 nm / sec to provide an electron transport layer having a thickness of 25 nm. The substrate temperature during vapor deposition was room temperature.

  Subsequently, lithium fluoride was deposited to a thickness of 0.5 nm at a deposition rate of 0.02 nm / sec. Finally, aluminum was deposited as a cathode to a thickness of 100 nm at a deposition rate of 2.0 nm / sec to produce an organic electroluminescent device. Vapor deposition was carried out while maintaining the vacuum state of the vapor deposition tank.

A DC voltage was applied to the produced organic electroluminescence device, and the organic electroluminescence device was continuously driven at a constant current density of 10 mA / cm ^{2 in} a dry atmosphere at room temperature. Initially, the voltage value was 6.2 V, and red light emission with a luminance of 1100 cd / m ² was confirmed. The luminance half-life was 3200 hours.

[Example 6]
In Example 5, instead of using the compound of exemplary compound A-18, an organic electroluminescent element was produced according to the procedure described in Example 5 except that the light emitting layer was formed of the compound of exemplary compound E-17. .

A DC voltage was applied to the produced organic electroluminescence device, and the organic electroluminescence device was continuously driven at a constant current density of 10 mA / cm ^{2 in} a dry atmosphere at room temperature. Initially, the voltage value was 6.5 V, and red light emission with a luminance of 1050 cd / m ² was confirmed. The luminance half-life was 3100 hours.

[Example 7]
In Example 5, instead of using the compound of Exemplified Compound A-18, an organic electroluminescent device was prepared according to the procedure described in Example 5 except that the light emitting layer was formed using the compound of Exemplified Compound G-2. Was made.

A DC voltage was applied to the produced organic electroluminescence device, and the organic electroluminescence device was continuously driven at a constant current density of 10 mA / cm ^{2 in} a dry atmosphere at room temperature. Initially, the voltage value was 6.1 V, and red light emission with a luminance of 1200 cd / m ² was confirmed. The half life of luminance was 3300 hours.

[Example 8]
In Example 5, instead of using the compound of Exemplified Compound A-18, an organic electroluminescent device was prepared according to the procedure described in Example 5 except that a light emitting layer was formed using the compound of Exemplified Compound G-9. Was made.

A DC voltage was applied to the produced organic electroluminescence device, and the organic electroluminescence device was continuously driven at a constant current density of 10 mA / cm ^{2 in} a dry atmosphere at room temperature. Initially, the voltage value was 6.2 V, and red light emission with a luminance of 1200 cd / m ² was confirmed. The half life of luminance was 3000 hours.

[Example 9]
In Example 5, instead of using the compound of Exemplified Compound A-18, an organic electroluminescent device was prepared according to the procedure described in Example 5 except that the light emitting layer was formed using the compound of Exemplified Compound H-2. Was made.

A DC voltage was applied to the produced organic electroluminescence device, and the organic electroluminescence device was continuously driven at a constant current density of 10 mA / cm ^{2 in} a dry atmosphere at room temperature. Initially, the voltage value was 6.1 V, and red light emission with a luminance of 1200 cd / m ² was confirmed. The luminance half-life was 3100 hours.

[Example 10]
In Example 5, instead of using the compound of Exemplified Compound E-15, an organic electroluminescent device was prepared according to the procedure described in Example 5 except that the light emitting layer was formed using the compound of Exemplified Compound H-4. Was made.

A DC voltage was applied to the produced organic electroluminescence device, and the organic electroluminescence device was continuously driven at a constant current density of 10 mA / cm ^{2 in} a dry atmosphere at room temperature. Initially, the voltage value was 6.3 V, and green light emission with a luminance of 1200 cd / m ² was confirmed. The luminance half-life was 3100 hours.

[Example 11]
A glass substrate having an ITO transparent electrode (anode) having a thickness of 110 nm was subjected to ultrasonic cleaning using a neutral detergent, Semico Clean (manufactured by Furuuchi Chemical), ultrapure water, acetone, and isopropanol. The substrate was dried with nitrogen gas and further UV / ozone cleaned. The cleaned substrate was fixed to the substrate holder of the vapor deposition apparatus, and the vapor deposition tank was depressurized to 1 × 10 ⁻⁵ Pa.

  First, bis [N-phenyl-N- (1-naphthyl)]-4,4′-diamino-1,1′-biphenyl was deposited on the ITO transparent electrode at a deposition rate of 0.1 nm / sec. A hole injection layer was provided.

  Next, exemplary compound E-17 was deposited at a deposition rate of 0.1 nm / sec to provide a 10 nm thick hole transport layer.

The CBP and Ir (ppy) ₃ which is a phosphorescent material represented by the formula (a1-1) are deposited on the hole transport layer at a deposition rate of 0.2 nm / sec and 0.016 nm / sec, respectively. A light emitting layer having a thickness of 25 nm was provided.

  Further, BPhen was deposited on the light emitting layer at a deposition rate of 0.1 nm / sec to provide a hole blocking layer (electron transport layer) having a thickness of 15 nm.

  Further, tris (8-quinolinolato) aluminum was deposited on the hole blocking layer at a deposition rate of 0.1 nm / sec to provide an electron transport layer having a thickness of 25 nm. The substrate temperature during vapor deposition was room temperature.

  Subsequently, lithium fluoride was deposited to a thickness of 0.5 nm at a deposition rate of 0.02 nm / sec. Finally, aluminum was deposited as a cathode to a thickness of 100 nm at a deposition rate of 2.0 nm / sec to produce an organic electroluminescent device. Vapor deposition was carried out while maintaining the vacuum state of the vapor deposition tank.

A DC voltage was applied to the produced organic electroluminescence device, and the organic electroluminescence device was continuously driven at a constant current density of 10 mA / cm ^{2 in} a dry atmosphere at room temperature. Initially, the voltage value was 5.8 V, and green light emission with a luminance of 2200 cd / m ² was confirmed. The half life of luminance was 1200 hours. It can be seen that the use of the compound of the present invention as a hole transport material in comparison with the organic electroluminescence device of Comparative Example 1 reduces the driving voltage, improves the light emission luminance, and increases the luminance half-life. .

  According to the present invention, the light emission efficiency, stability, and durability of an organic electroluminescence device using light emission from a phosphorescent material can be enhanced.

It is the schematic which shows an example of the layer structure of an organic electroluminescent element. It is the schematic which shows an example of the layer structure of an organic electroluminescent element. It is the schematic which shows an example of the layer structure of an organic electroluminescent element. It is the schematic which shows an example of the layer structure of an organic electroluminescent element. It is the schematic which shows an example of the layer structure of an organic electroluminescent element. It is the schematic which shows an example of the layer structure of an organic electroluminescent element. It is the schematic which shows an example of the layer structure of an organic electroluminescent element. It is the schematic which shows an example of the layer structure of an organic electroluminescent element. It is the schematic which shows an example of the layer structure of an organic electroluminescent element. It is the schematic which shows an example of the layer structure of an organic electroluminescent element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Anode 3 Hole injection transport layer 3 'Hole injection layer 3 "Hole transport layer 3a Hole injection transport component 4 Light emission layer 4a Light emission component 5 Electron injection transport layer 5' Hole blocking layer (electron transport layer)
5a Electron injection transport component 6 Cathode 7 Power supply

Claims (8)

An organic electroluminescent element having a functional layer including a light emitting layer sandwiched between a pair of electrodes,
The light emitting layer contains a phosphorescent material;
Any one of the functional layers is an organic electroluminescent device containing at least one compound represented by the general formula (1).

(In Formula (1),
Ar _{1 to} Ar ₄ represent a substituted or unsubstituted aryl group,
Ar ₁ and Ar ₂ , and Ar ₃ and Ar ₄ may form a nitrogen-containing heterocycle together with the nitrogen atom to which they are bonded,
R ₁ and R ₂ represent a hydrogen atom, a linear, branched or cyclic alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group,
Z ₁ and Z ₂ represent a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group, a linear, branched or cyclic alkoxy group, or a substituted or unsubstituted aryl group,
X ₁ and X ₂ represent a substituted or unsubstituted arylene group)   The organic electroluminescent element according to claim 1, wherein the phosphorescent material is a transition metal complex.   The organic electroluminescence device according to claim 2, wherein the transition metal is iridium or platinum. The organic electroluminescent device according to claim 1, wherein in the compound represented by the general formula (1), X ₁ and X ₂ are groups represented by the following general formula (2).
-(A ₁ -X ₁₁ ) _m -A _2- (2)
(Wherein A ₁ and A ₂ represent a substituted or unsubstituted phenylene group,
X ₁₁ represents a single bond, an oxygen atom or a sulfur atom,
m represents 0 or 1)   The organic electroluminescence device according to any one of claims 1 to 4, wherein the layer containing the compound represented by the general formula (1) is a hole injection transport layer.   The organic electroluminescent element as described in any one of Claims 1-4 whose layer containing the compound represented by General formula (1) is a light emitting layer.   The organic electroluminescent element according to claim 1, wherein the functional layer sandwiched between the pair of electrodes further includes an electron injecting and transporting layer. The organic electroluminescent element according to claim 1, wherein at least one hole transport layer, a light emitting layer, and an electron transport layer are sandwiched between the pair of electrodes.

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