JP6657895B2 - Organic electroluminescence element, display device and lighting device - Google Patents

Description

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

  2. Description of the Related Art An organic electroluminescence device (hereinafter, also referred to as an “organic EL device”) is a thin-film type all-solid structure in which an organic thin film layer (single-layer portion or multilayer portion) containing an organic luminescent substance is provided between an anode and a cathode. Element. When a voltage is applied to such an organic EL element, electrons are injected from the cathode into the organic thin film layer and holes are injected from the anode, and these are recombined in the light emitting layer (organic light emitting substance containing layer) to generate excitons. The organic EL element is a light emitting element utilizing emission (fluorescence / phosphorescence) of light from these excitons, and is a technology expected as a next-generation flat display or illumination.

  Furthermore, since an organic EL device using phosphorescence emission from an excited triplet, which can realize a luminous efficiency about four times in principle compared with an organic EL device using fluorescence emission, since Princeton University reported, Research and development of a layer structure of a light emitting element and an electrode are being carried out all over the world, including the development of a material exhibiting phosphorescence at room temperature.

  As described above, the phosphorescent light emitting method is a method having a very high potential. However, in an organic EL device using phosphorescent light emission, it is significantly different from that using fluorescent light emission, and a method of controlling the position of the light emission center, particularly How to stably emit light by performing recombination inside the light emitting layer is an important technical problem in improving the light emitting efficiency and light emitting life of the device.

  Therefore, in recent years, a multilayer stacked element including an electron blocking layer located on the anode side of the light emitting layer, a hole blocking layer located on the cathode side of the light emitting layer, and the like adjacent to the light emitting layer is well known. ing. In addition, a mixed layer using a phosphorescent compound and a host compound as a light-emitting dopant is often used for the light-emitting layer.

  On the other hand, from the viewpoint of materials, there is great expectation for creating new materials for improving device performance. For example, the following organic EL material using the following comparative compound 1 as a host compound of a phosphorescent compound and the following comparative compound 2 as a hole transport material has been reported (see Patent Document 1).

  With the combination of these specific compounds described in Patent Document 1, the injection balance of holes and electrons into the light emitting layer can be adjusted, and the luminous efficiency of the device has been considerably improved. However, after storing the organic EL devices formed with these compounds at a high temperature, a remarkable decrease in emission intensity was observed. Further, it has been revealed that the emission life at high temperature is shorter than the life at room temperature. There is also room for further improvement in luminous efficiency.

U.S. Patent Application Publication No. 2015/0243903

  The present invention has been made in view of the above problems and circumstances, and a solution to the problem is to use a specific aromatic heterocyclic derivative for an organic EL device, to have high luminous efficiency, and to store it at a high temperature. Another object of the present invention is to provide an organic EL device which has a small change over time in light emission intensity and a long light emission life at high temperatures. Another object of the present invention is to provide a display device and a lighting device each including the organic EL element.

  The present inventor has studied the causes of the above-mentioned problems in order to solve the above-mentioned problems, and as a result, has found that an aromatic heterocyclic derivative having a specific structure is effective in solving the above-mentioned problems, and has reached the present invention.

  That is, the above object according to the present invention is solved by the following means.

  1. An organic electroluminescence device in which an organic layer including a light emitting layer and an electron blocking layer is sandwiched between an anode and a cathode, wherein the light emitting layer has an aromatic heterocyclic ring having a structure represented by the following general formula (1). An organic electroluminescent device comprising a derivative, and wherein the electron blocking layer contains at least one of aromatic heterocyclic derivatives having a structure represented by the following general formulas (3) to (6). Luminescent element.

(In the general formula (1),
Y ₁ , Y ₂ and Y ₃ each independently represent CR ′ or a nitrogen atom, and at least one of Y ₁ , Y ₂ and Y ₃ is a nitrogen atom.
R ′, Ar ₁ and Ar ₂ are each independently
Hydrogen atom,
A substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or
Represents a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms.
R ′, Ar ₁ and Ar ₂ are not all hydrogen atoms at the same time.
L is
Single bond,
A substituted or unsubstituted alkylene group having 1 to 12 carbon atoms,
A substituted or unsubstituted arylene group having 6 to 30 ring carbon atoms,
It represents a substituted or unsubstituted heteroarylene group having 5 to 30 ring atoms, or a divalent linking group composed of a combination thereof.
R ₁ and R ₂ each independently represent a substituent.
n ₁ represents an integer of 0 to 4, _{n 2} is an integer of 0 to 3 and Table, _{n 1} and _{n 2} are not to become 1 at the same time.
n ₁₃ represents an integer of 0-1.
When n ₁ and n ₂ are each 2 or more, R ₁ and R ₂ may be the same or different, and when R ₁ and R ₂ are adjacent to each other, a ring may be formed.
A ₁ and A ₂ represent a compound represented by the following general formula (2). )

(In the general formula (2), Z ₁ and Z ₂ each independently represent an aromatic heterocyclic ring which may have a substituent or an aromatic hydrocarbon ring which may have a substituent; ₃ represents a divalent linking group or a simple bond.)

(In the general formulas (3) to (6),
R _{3 to} R ₇ each independently represent a substituent.
n ₃ , n ₄ , n _5, and n ₇ each independently represent an integer of 0 to 4, and n ₆ represents an integer of 0 to 2.
When n _{3 to} n ₇ are each 2 or more, R _{3 to} R ₇ may be the same or different, and when R _{3 to} R ₇ are adjacent to each other, a ring may be formed.
Ar ₃ and Ar ₄ are each independently:
A substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or
Represents a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms.
X represents an oxygen atom, a sulfur atom or _{N-R 8,.}
R ₈ is a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or
A substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or
Represents a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms. )

2. An organic electroluminescence device in which an organic layer including a light emitting layer and an electron blocking layer is sandwiched between an anode and a cathode, wherein the light emitting layer has an aromatic heterocyclic ring having a structure represented by the following general formula (7). An organic electroluminescent device comprising a derivative, and wherein the electron blocking layer contains at least one of aromatic heterocyclic derivatives having a structure represented by the following general formulas (3) to (6). Luminescent element.

  (In the general formula (7),
Y ₁ , Y ₂ And Y ₃ Each independently represents CR ′ or a nitrogen atom; ₁ , Y ₂ And Y ₃ At least one is a nitrogen atom.
R ', Ar ₁ And Ar ₂ Are, independently of each other,
  Hydrogen atom,
  A substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or
  Represents a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms.
  R ', Ar ₁ And Ar ₂ Are not all hydrogen atoms at the same time.
L is
  Single bond,
  A substituted or unsubstituted alkylene group having 1 to 12 carbon atoms,
  A substituted or unsubstituted arylene group having 6 to 30 ring carbon atoms,
  A substituted or unsubstituted heteroarylene group having 5 to 30 ring atoms, or
  It represents a divalent linking group consisting of these combinations.
R ₁ And R ₂ Each independently represents a substituent.
n ₁ Represents an integer of 0 to 4; ₂ Represents an integer of 0 to 3.
  Note that n ₁ And n ₂ Is 2 or more, R ₁ And R ₂ May be the same or different, and R ₁ And R ₂ May be adjacent to each other to form a ring.
A ₁ And A ₂ Represents a compound represented by the following general formula (2). )

  (In the general formula (2), Z ₁ And Z ₂ Each independently represents an aromatic heterocyclic ring which may have a substituent, or an aromatic hydrocarbon ring which may have a substituent; ₃ Represents a divalent linking group or a simple bond. )

  (In the general formulas (3) to (6),
R ₃ ~ R ₇ Each independently represents a substituent.
n ₃ , N ₄ , N ₅ And n ₇ Each independently represents an integer of 0 to 4; ₆ Represents an integer of 0 to 2.
  Note that n ₃ ~ N ₇ Is 2 or more, R ₃ ~ R ₇ May be the same or different, and R ₃ ~ R ₇ May be adjacent to each other to form a ring.
Ar ₃ And Ar ₄ Are, independently of each other,
  A substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or
  Represents a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms.
X represents an oxygen atom, a sulfur atom, or NR ₈ Represents
R ₈ Is a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or
  A substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or
  Represents a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms. )

3. 2. The organic electroluminescent device according to the above item 1, wherein the compound represented by the general formula (1) is represented by the following general formula (8).

4. Before SL Y ₁ to Y ₃ is an organic electroluminescent device according to any one of the three from the 1, characterized in that all represent nitrogen atom.

5. Before SL Ar ₁ and Ar ₂ An organic electroluminescence device according from the 1 in any one of the 4, characterized in that a substituted or unsubstituted ring forming aryl group having 6 to 30 carbon atoms.

  6. The organic electroluminescence device according to any one of the above items 1 to 5, wherein the light emitting layer contains a phosphorescent light emitting dopant.

  7. 7. The organic electroluminescence device according to any one of the above items 1 to 6, wherein the light emitting layer further contains a host compound having a structure different from the structure of the aromatic heterocyclic derivative.

  8. The organic electroluminescence device according to any one of the above items 1 to 7, wherein the light emitting layer and the electron blocking layer are adjacent to each other.

  9. A display device, comprising: the organic electroluminescence element according to any one of the above items 1 to 8.

  10. A lighting device comprising the organic electroluminescent element according to any one of the above items 1 to 8.

  According to the above-described means of the present invention, the use of a specific aromatic heterocyclic derivative for an organic EL device has a high luminous efficiency, a small change with time in luminous intensity even after storage at a high temperature, and a luminescence at a high temperature. An organic EL element having a long life can be provided. Further, a display device and a lighting device each including the organic EL element can be provided.

FIG. 1 is a schematic perspective view illustrating an example of a configuration of a display device of the present invention. FIG. 2 is a schematic perspective view showing an example of a configuration of a display unit A shown in FIG. FIG. 2 is a schematic perspective view illustrating an example of a lighting device using the organic EL element of the present invention. FIG. 2 is a schematic sectional view showing an example of a lighting device using the organic EL element of the present invention.

Hereinafter, the present invention, its components, and embodiments and modes for carrying out the present invention will be described in detail. In addition, in this application, "-" is used in the meaning including the numerical value described before and after it as a lower limit and an upper limit.
Hereinafter, embodiments for carrying out the present invention will be described in detail, but the present invention is not limited thereto.

<< Effect mechanism or action mechanism of the effect of the present invention >>
First, the mechanism of manifesting or acting the effects of the present invention will be described. Although the mechanism of manifesting or acting the effects of the present invention has not been clarified, it is speculated as follows.

In general, in the case of a compound such as Comparative Compound 1 of Patent Document 1 in which an aromatic ring group is substituted at the para-position of the biphenyl skeleton, Tg (glass transition point) tends to increase and crystallization tends to occur. . However, by introducing a substituent at each meta position of the biphenyl skeleton represented by the general formula (1) of the present invention, aggregation and crystallization can be suppressed without lowering Tg.
On the other hand, a compound such as Comparative Compound 2 of Patent Document 1 has an advantage of increasing Tg because the aromatic heterocyclic skeleton is planar and the conjugated system is spread, but the aromatic heterocyclic skeleton has a linear structure. There is a disadvantage that it is easy to crystallize. Therefore, by selecting an aromatic heterocyclic skeleton such as the general formulas (3) to (6) of the present invention and introducing a substituent at a specific position, the intermolecular interaction can be controlled and the Tg can be reduced. Agglomeration and crystallization can be suppressed without lowering.

As described above, when the organic EL devices in which the comparative compound 1 and the comparative compound 2 were formed as the light emitting layer and the electron blocking layer, respectively, were stored at a high temperature, a remarkable decrease in the emission intensity was observed. When the comparative compound 1 or the comparative compound 2 is used, the film quality changes due to the passage of time at a high temperature, and the interface between the light emitting layer and the electron blocking layer is distorted. As a result, the injection balance of holes and electrons is disrupted. It is estimated that the emission intensity has decreased. On the other hand, when the compound of the present invention is used, it is considered that the change at the interface with the passage of time at a high temperature is small and the decrease in emission intensity is suppressed.
Regarding the luminescence lifetime at high temperature, when the comparative compound 1 or the comparative compound 2 is used, a change in state occurs at the interface between the luminescent layer and the electron blocking layer or in the film over time, and the lifetime is reduced. It is presumed that when the compound according to the present invention was used in combination, the change in the interface between the light emitting layer and the electron blocking layer and in the film was small and the reduction in the life was suppressed.
That is, the present invention combines a compound having a structure represented by the general formula (1) with a compound having a structure represented by the general formulas (3) to (6) to provide an unprecedented excellent compound. It has a feature in that it has been found that it has an effect.

《Organic electroluminescence device》
Next, the organic electroluminescence device of the present invention will be described.
The organic electroluminescent device of the present invention is an organic electroluminescent device in which an organic layer including a light emitting layer and an electron blocking layer is sandwiched between an anode and a cathode, wherein the light emitting layer is represented by the following general formula (1). Wherein the electron blocking layer contains at least one of the aromatic heterocyclic derivatives having a structure represented by the following general formulas (3) to (6). It is characterized by containing. This feature is a technical feature common to the inventions according to claims 1 to 10.

  First, general formula (1) will be described.

In the general formula (1), Y ₁ , Y ₂ and Y ₃ each independently represent CR ′ or a nitrogen atom, and at least one of Y ₁ , Y ₂ and Y ₃ is a nitrogen atom.

More preferably, two or three of Y ₁ , Y _2, and Y ₃ are nitrogen atoms, and more preferably, Y ₁ , Y _2, and Y ₃ are all nitrogen atoms.

R ′, Ar ₁ and Ar ₂ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms. . However, R ′, Ar ₁ and Ar ₂ are not all hydrogen atoms at the same time.

The alkyl group having 1 to 12 carbon atoms represented by R ′, Ar ₁ or Ar ₂ may have a branched structure even if it is linear as long as the function of the compound of the present invention is not impaired. And a cyclic structure such as a cycloalkyl group.

Examples of the alkyl group having 1 to 12 carbon atoms represented by R ′, Ar ₁ or Ar ₂ include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, and a nonyl group. Groups, decyl, undecyl, dodecyl, isopropyl, neopentyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclooctyl and the like.

The aryl group having 6 to 30 ring carbon atoms (also referred to as an aromatic hydrocarbon ring group) represented by R ′, Ar ₁ or Ar ₂ may be a non-condensed or condensed ring. , Phenyl group, naphthyl group, anthryl group, phenanthryl group, pyrenyl group, chrysenyl group, biphenyl group, terphenyl group, quarter phenyl group, fluoranthenyl group, triphenylenyl group, fluorenyl group, azulenyl group, acenaphthenyl group, indenyl group, And an indenofluorenyl group.

In order to appropriately maintain the excited triplet energy level (T ₁ energy level) of the compound of the present invention, the aryl group having 6 to 30 ring carbon atoms represented by R ′, Ar ₁ or Ar ₂ includes: A phenyl group, a naphthyl group, a phenanthryl group, a biphenyl group, a terphenyl group, a quarterphenyl group, a triphenylenyl group, and a fluorenyl group are preferred.

The alkyl group and the aryl group represented by R ′, Ar ₁ or Ar ₂ each may further have a substituent within a range that does not inhibit the function of the compound of the present invention. Specific examples include the same groups as the substituents represented by R ₁ or R ₂ described below.

  Preferably, R 'is a hydrogen atom or an alkyl group, more preferably a hydrogen atom.

Preferably, Ar ₁ and Ar ₂ are an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 30 ring carbon atoms, more preferably, Ar ₁ and Ar ₂ are an alkyl group having 4 or less carbon atoms or It is an aryl group having 6 to 12 ring carbon atoms.

R ₁ and R ₂ each independently represent a substituent. Examples of the substituent represented by R ₁ and R ₂ include an alkyl group (for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group, a dodecyl group, Tridecyl group, tetradecyl group, pentadecyl group, etc.), cycloalkyl group (eg, cyclopentyl group, cyclohexyl group, etc.), alkenyl group (eg, vinyl group, allyl group, etc.), alkynyl group (eg, ethynyl group, propargyl group, etc.) An aromatic hydrocarbon group (also referred to as an aromatic hydrocarbon ring group, an aromatic carbocyclic group, an aryl group, etc .; for example, phenyl group, p-chlorophenyl group, mesityl group, tolyl group, xylyl group, naphthyl group, anthryl group , Azulenyl, acenaphthenyl, fluorenyl, phenanthryl, indenyl, pyrenyl , A biphenylyl group, etc.), an aromatic heterocyclic group (for example, pyridyl group, pyrazyl group, pyrimidinyl group, triazyl group, furyl group, pyrrolyl group, imidazolyl group, benzimidazolyl group, pyrazolyl group, pyrazinyl group, triazolyl group (for example, 1 , 2,4-triazol-1-yl group, 1,2,3-triazol-1-yl group, etc.), oxazolyl group, benzoxazolyl group, thiazolyl group, isoxazolyl group, isothiazolyl group, furazanyl group, thienyl group Quinolyl group, benzofuryl group, dibenzofuryl group, benzothienyl group, dibenzothienyl group, indolyl group, carbazolyl group, quinoxalinyl group, pyridazinyl group, triazinyl group, quinazolinyl group, phthalazinyl group, etc., heterocyclic group (for example, pyrrolidyl group) , Imidazolidyl group, morpholi A methoxy group, an ethoxy group, a propyloxy group, a pentyloxy group, a hexyloxy group, an octyloxy group, a dodecyloxy group, etc.), a cycloalkoxy group (eg, a cyclopentyloxy group) , Cyclohexyloxy group, etc.), aryloxy group (eg, phenoxy group, naphthyloxy group, etc.), alkylthio group (eg, methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group, etc.), Cycloalkylthio group (eg, cyclopentylthio group, cyclohexylthio group, etc.), arylthio group (eg, phenylthio group, naphthylthio group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group) Butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (eg, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), sulfamoyl group (eg, aminosulfonyl group, methylaminosulfonyl group, Dimethylaminosulfonyl, butylaminosulfonyl, hexylaminosulfonyl, cyclohexylaminosulfonyl, octylaminosulfonyl, dodecylaminosulfonyl, phenylaminosulfonyl, naphthylaminosulfonyl, 2-pyridylaminosulfonyl, etc.), acyl group (For example, acetyl, ethylcarbonyl, propylcarbonyl, pentylcarbonyl, cyclohexylcarbonyl, octylcarbonyl, 2 Ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc., acyloxy group (for example, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group) Phenylcarbonyloxy group, etc.), amide group (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, Octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc.), carbamoyl group (for example, , Aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl Group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), ureido group (for example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido group, dodecylureido group, phenylureido group, naphthylureide Group, 2-pyridylaminoureido group, etc.), sulfinyl group (for example, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexyl group) Silsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group, etc., alkylsulfonyl group (for example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl) Group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc.), arylsulfonyl group or heteroarylsulfonyl group (eg, phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (eg, amino group, ethyl Amino group, dimethylamino group, butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, naphthylamino group, 2-pyridylamino Etc.), halogen atoms (eg, fluorine atom, chlorine atom, bromine atom, etc.), fluorinated hydrocarbon groups (eg, fluoromethyl group, trifluoromethyl group, pentafluoroethyl group, pentafluorophenyl group, etc.), cyano group Nitro group, hydroxy group, mercapto group, silyl group (for example, trimethylsilyl group, triisopropylsilyl group, triphenylsilyl group, phenyldiethylsilyl group, etc.), and phosphono group.

  These substituents may be further substituted by the above-mentioned substituents, and a plurality of these substituents may be bonded to each other to form a ring structure.

In the general formula (1), _{n 1} represents an integer of 0 to 4, _{n 2} represents an integer of 0 to 3. Of these, n ₁ + n ₂ = 1 is preferred. _{Further, n 13} represents an integer of 0-1.

When n ₁ and n ₂ are each 2 or more, that is, when a plurality of R ₁ and R ₂ are present, R ₁ and R ₂ may be the same or different, and R ₁ and R ₂ are adjacent to each other In this case, they may be bonded to each other to form a ring.

Among the substituents represented by R ₁ and R ₂ , preferred are an alkyl group and an aryl group, and an alkyl group is particularly preferred.

  L is a single bond, a substituted or unsubstituted alkylene group having 1 to 12 carbon atoms, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, a substituted or unsubstituted heteroatom having 5 to 30 ring-forming atoms. Represents a divalent linking group comprising an arylene group or a combination thereof.

  The alkylene group having 1 to 12 carbon atoms represented by L may be linear or have a branched structure, and may have a cyclic structure such as a cycloalkylene group.

Specific examples of the alkylene group having 1 to 12 carbon atoms include divalent divalent groups derived by removing one hydrogen atom from the alkyl group having 1 to 12 carbon atoms represented by R ′, Ar ₁ or Ar ₂ . Groups.

The arylene group having 6 to 30 ring carbon atoms represented by L may be non-condensed or a condensed ring. Specific examples of the arylene group having 6 to 30 ring carbon atoms include the aforementioned R ', A divalent group derived by removing one hydrogen atom from the aryl group having 6 to 30 ring carbon atoms represented by Ar ₁ or Ar ₂ .

For the purpose of appropriately maintaining the T ₁ energy level of the compound of the present invention, examples of the arylene group having 6 to 30 ring carbon atoms represented by L include an o-phenylene group, an m-phenylene group, a p-phenylene group, Naphthalenediyl, phenanthylenediyl, biphenylene, terphenylene, quarterphenylene, triphenylenediyl, and fluorenediyl are preferred.

  Examples of the heteroarylene group having 5 to 30 ring atoms represented by L include a pyridine ring, a pyrazine ring, a pyrimidine ring, a piperidine ring, a triazine ring, a pyrrole ring, an imidazole ring, a pyrazole ring, a triazole ring, and an indole ring. , Isoindole, benzimidazole, furan, benzofuran, isobenzofuran, dibenzofuran, thiophene, benzothiophene, silole, benzosilole, dibenzosilole, quinoline, isoquinoline, quinoxaline, phenanthane Lysine ring, phenanthroline ring, acridine ring, phenazine ring, phenoxazine ring, phenothiazine ring, phenoxatiin ring, pyridazine ring, oxazole ring, oxadiazole ring, benzoxazole ring, thiazole ring, thiadiazole ring, Zothiazole ring, benzodifuran ring, thienothiophene ring, dibenzothiophene ring, benzodithiophene ring, cyclazine ring, kindrin ring, tepenidine ring, quinindrin ring, triphenodithiazine ring, triphenodioxazine ring, phenanthrazine ring, anthrazine ring, Perimidine ring, naphthofuran ring, naphthothiophene ring, benzodithiophene ring, naphthodifuran ring, naphthodithiophene ring, anthrafuran ring, anthradidifuran ring, anthrathiophene ring, anthradithiophene ring, thianthrene ring, phenoxathiin ring, naphtho A thiophene ring, a carbazole ring, a carboline ring, a diazacarbazole ring (in which any two or more of the carbon atoms constituting the carbazole ring are replaced by nitrogen atoms), an azadibenzofuran ring (dibenzo A ring in which one or more of the carbon atoms that constitute the orchid ring is replaced with a nitrogen atom), an azadibenzothiophene ring (in which one or more of the carbon atoms that constitute the dibenzothiophene ring are replaced with a nitrogen atom) And a divalent group derived by removing two hydrogen atoms from an indolocarbazole ring, an indenoindole ring and the like.

  The heteroarylene group having 5 to 30 ring atoms represented by L is more preferably a pyridine ring, a pyrazine ring, a pyrimidine ring, a piperidine ring, a triazine ring, a dibenzofuran ring, a dibenzothiophene ring, a carbazole ring, or a carboline ring. And a divalent group derived by removing two hydrogen atoms from a diazacarbazole ring or the like.

The alkylene group, the arylene group, and the heteroarylene group represented by L may each further have a substituent as long as the function of the compound of the present invention is not impaired. And the same groups as the substituents represented by R ′, Ar ₁ or Ar ₂ of the above.
Preferred of L is a single bond or an arylene group, and a single bond is particularly preferred. In the case of an arylene group, it preferably has 6 to 12 ring carbon atoms.

In the general formula (1), A ₁ and A ₂ represent a compound represented by the following general formula (2).

In the general formula (2), Z ₁ and Z ₂ each independently represent an aromatic heterocyclic ring which may have a substituent or an aromatic hydrocarbon ring which may have a substituent, and Z ₃ Represents a divalent linking group or a simple bond.

In the general formula (2), Z ₁ and Z ₂ each represent an atom group forming an aromatic heterocyclic ring or an aromatic hydrocarbon ring, and examples of the aromatic heterocyclic ring include a furan ring, a thiophene ring, a pyridine ring, and a pyridazine ring. , Pyrimidine ring, pyrazine ring, triazine ring, benzimidazole ring, oxadiazole ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indole ring, benzimidazole ring, benzothiazole ring, benzoxazole ring, quinoxaline ring, quinazoline And a phthalazine ring, a carbazole ring, a carboline ring, and a diazacarbazole ring (a ring in which one of carbon atoms of a hydrocarbon ring constituting the carboline ring is further substituted with a nitrogen atom). As the aromatic hydrocarbon ring, benzene ring, biphenyl ring, naphthalene ring, azulene ring, anthracene ring, phenanthrene ring, pyrene ring, chrysene ring, naphthacene ring, triphenylene ring, o-terphenyl ring, m-terphenyl ring, Examples include a p-terphenyl ring, an acenaphthene ring, a coronene ring, a fluorene ring, a fluoranthrene ring, a pentacene ring, a perylene ring, a pentaphene ring, a picene ring, a pyranthrene ring, and an anthranthrene ring.

The aromatic hydrocarbon ring and the aromatic heterocyclic ring represented by Z ₁ and Z ₂ each may further have a substituent as long as the function of the compound of the present invention is not impaired. Examples of the group include the same groups as those described above for R ′, Ar _{1 and} Ar ₂ .
Of the rings formed by Z ₁ and Z ₂ , a preferred one is an aromatic hydrocarbon ring, and a more preferred one is a benzene ring.

Examples of the divalent linking group is Z ₃ represents an alkylene, alkenylene, alkynylene, other hydrocarbon groups arylene or the like may also comprise heteroatoms such as heteroarylene, also thiophen-2,5 It may be a divalent linking group derived from a compound having an aromatic heterocycle (also referred to as a heteroaromatic compound) such as a diyl group or a pyrazine-2,3-diyl group, or a chalcogen such as oxygen or sulfur. It may be an atom. Further, a group linked via a hetero atom such as an alkylimino group, a dialkylsilanediyl group or a diarylgermandiyl group may be used. A simple bond is a bond that directly bonds the connecting substituents.
Among the groups represented by Z ₃ , a preferable one is a bond.

The alkylene group, alkenylene group, alkynylene group, arylene group, heteroarylene group and the like represented by Z ₃ each may further have a substituent as long as the function of the compound of the present invention is not impaired. Examples of the group include the same groups as those described above for R ′, Ar _{1 and} Ar ₂ .

The compound represented by the general formula (1) is more preferably represented by the following general formulas (7) and (8). In the general formulas (7) and (8), Y _{1 to} Y ₃ , L, R ₁ , R ₂ , A ₁ , A ₂ , n ₁ , n ₂ , Ar ₁ and Ar ₂ are the same as the general formulas described above. It has the same meaning as Y _{1 to} Y ₃ , L, R ₁ , R ₂ , A ₁ , A ₂ , n ₁ , n ₂ , Ar ₁ and Ar ₂ in (1).

  Specific examples of the compounds having the structures represented by the general formulas (1), (7) and (8) are shown below, but are not limited thereto.

Compounds having structures represented by general formulas (1), (7) and (8) of the present invention can be prepared by known synthesis methods, for example, as described in J. Am. Org. Chem. , 42, 1821 (1977); Am. Chem. Soc. , 101, 4992 (1977); Chem. Rev .. , 95, 2457 (1995); Org. Chem. , 53, 918 (1988), etc., cross-coupling reaction using Pd forming a carbon-carbon bond, Angew. Chem. Int. Ed. 1998, 37, 2046 and the like, a cross-coupling reaction for forming a carbon-nitrogen bond using Pd, Angew. Chem. Int. Ed. It can be synthesized by using a carbon-nitrogen bond forming reaction using Cu described in 2003, 42, 5400.
Hereinafter, the synthesis of the exemplary compound (1) will be described as a specific synthesis example.

(Synthesis of Intermediate 3)
Under a nitrogen atmosphere, 25 g of compound 1 and 10 g (60 mmol) of compound 2 were dissolved in 50 ml of N, N-dimethylacetamide. 4.6 g of copper powder and 10 g of potassium carbonate were added thereto, followed by stirring at 150 ° C. for 3 hours. Next, ethyl acetate was added to the reaction solution, which was then extracted and washed with water. The ethyl acetate layer was concentrated under reduced pressure and purified by column chromatography (silica gel, developing solution toluene / heptane). Thus, 15 g of intermediate 3 (colorless oil) was obtained (yield: 77.6%). The structure of Intermediate 3 was confirmed using NMR, mass spectrum, and the like.

(Synthesis of Intermediate 5)
Under a nitrogen atmosphere, 14.1 g (43.7 mmol) of Intermediate 3, 12.2 g of Compound 4, 13 g of potassium acetate and 3.6 g of PdCl ₂ dppf were added to 120 ml of DMSO, and the mixture was stirred at 90 ° C. for 2 hours. did. Next, ethyl acetate was added, and the mixture was extracted and washed with water. The organic layer was concentrated under reduced pressure and purified by column chromatography (silica gel, developing solution toluene / heptane). Thus, 11.0 g (yellow oil) of Intermediate 5 was obtained (yield: 65%). The structure of the intermediate 5 was confirmed using NMR, mass spectrum, and the like. PdCl ₂ dppf is [1,1-Bis (diphenylphosphino) ferrocene] dichloropalladium, and DMSO is dimethyl sulfoxide.

(Synthesis of Exemplified Compound (1))
Under a nitrogen atmosphere, 1.4 g (3.6 mmol) of Intermediate 5, 1.4 g of Intermediate 6, 1.5 g of potassium carbonate, 0.42 g of Pd (PPh ₃ ) ₄ , 40 ml of tetrahydrofuran, and 4 ml of water The mixture was added and stirred at 70 ° C. for 2 hours. Ethyl acetate was added to the reaction solution, extracted, washed with water, the organic layer was concentrated under reduced pressure, and purified by column chromatography (silica gel, developing solution toluene / heptane). Thus, 0.79 g (white crystal) of the exemplary compound (1) was obtained (yield: 40%). The structure of the exemplified compound (1) was confirmed using NMR, mass spectrum, and the like.
Other compounds of the present invention can be synthesized in a similar manner.

  In the present invention, the light emitting layer preferably contains, as a host compound, an aromatic heterocyclic derivative having a structure represented by the general formula (1). Note that the light emitting layer preferably contains a phosphorescent dopant. Further, it is preferable that the light emitting layer further contains a host compound having a structure different from the aromatic heterocyclic derivative having the structure represented by the general formula (1) (that is, a known host compound). The detailed structure of the light emitting layer, the phosphorescent light emitting dopant, and the host compound having a structure different from the aromatic heterocyclic derivative having the structure represented by the general formula (1) will be described later.

  Next, general formulas (3) to (6) will be described.

In the general formulas (3) to (6), R _{3 to} R ₇ each independently represent a substituent.
In formulas (3) to (6), the substituents represented by R _{3 to} R ₇ are the same as the substituents represented by R ₁ and R ₂ .

In the general formulas (3) to (6), Ar ₃ and Ar ₄ are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted ring-forming carbon group having 6 to 30 carbon atoms. Represents an aryl group.
In the general formula (3) ~ (6), X represents an oxygen atom, a sulfur atom or _{N-R 8,.}
In the general formulas (3) to (6), R ₈ is a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or substituted or unsubstituted. Represents an unsubstituted heteroaryl group having 5 to 30 ring atoms.

The alkyl group and the aryl group represented by Ar _3, Ar ₄ and R ₈ represent the same groups as Ar ₁ or Ar ₂ .
Examples of the heteroaryl group represented by R ₈ include a monovalent group obtained by adding one hydrogen atom to the heteroarylene group represented by L.
The above groups represented by Ar _3, Ar ₄ and R ₈ may each further have a substituent as long as the function of the compound of the present invention is not impaired. Examples of such a substituent include those described above. Examples include the same groups as the substituents represented by R ′, Ar _{1 and} Ar ₂ .
Preferred among the groups represented by X is N-R _8.
Among the general formulas (3) to (6), a preferable one is the general formula (3).

In the general formulas (3) to (6), n ₃ , n ₄ , n ₅ and n ₇ each independently represent an integer of 0 to 4, and n ₆ represents an integer of 0 to 2.

n ₃ If ~n ₇ each represents 2 or more, i.e., if R ₃ to R ₇ are present in _plural, R 3 to R ₇ may each be the same or _different, R 3 to R ₇ are adjacent In this case, they may be bonded to each other to form a ring.

  Specific examples of the compounds having the structures represented by the general formulas (3) to (6) are shown below, but are not limited thereto. These compounds can be synthesized by those skilled in the art who have read the present specification according to a conventionally known method.

<< Constituent Layer of Organic EL Element >>
As a typical device configuration of the organic EL device of the present invention, the following configurations can be raised, but the present invention is not limited thereto.
(1) anode / hole transport layer / electron blocking layer / light emitting layer / cathode (2) anode / hole transport layer / electron blocking layer / light emitting layer / electron transport layer / cathode (3) anode / hole transport layer / Electron blocking layer / light emitting layer / electron transport layer / electron injection layer / cathode (4) anode / hole injection layer / hole transport layer / electron blocking layer / light emitting layer / electron transport layer / electron injection layer / cathode (5) Anode / Hole Injection Layer / Hole Transport Layer / Electron Blocking Layer / Emitting Layer / Hole Blocking Layer / Electron Transport Layer / Electron Injection Layer / Cathode Among the above, the configurations of (4) and (5) are preferable, and in particular, The configuration of (5) is preferable.

  In the organic EL device of the present invention, the light emitting layer and the electron blocking layer are preferably adjacent to each other, but another layer may be present between the light emitting layer and the electron blocking layer. Note that being adjacent means that the light-emitting layer and the electron blocking layer are in contact with each other without passing through another layer.

  The light emitting layer according to the present invention is composed of a single layer or a plurality of layers, and when there are a plurality of light emitting layers, a non-light emitting intermediate layer may be provided between the light emitting layers.

  If necessary, a hole blocking layer (also referred to as a hole blocking layer) or an electron injection layer (also referred to as a cathode buffer layer) may be provided between the light emitting layer and the cathode. A hole injection layer (also referred to as an anode buffer layer) may be provided therebetween.

  The electron transport layer used in the present invention is a layer having a function of transporting electrons. In a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. Further, it may be composed of a plurality of layers.

  The hole transport layer used in the present invention is a layer having a function of transporting holes. In a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer. Further, it may be composed of a plurality of layers.

  In the above-described typical device configuration, a layer excluding the anode and the cathode is also referred to as an “organic layer”.

(Tandem structure)
Further, the organic EL element of the present invention may be a so-called tandem element in which a plurality of light emitting units each including at least one light emitting layer are stacked.

  As a typical element configuration of a tandem structure, for example, the following configuration can be given.

Anode / first light emitting unit / second light emitting unit / third light emitting unit / cathode anode / first light emitting unit / intermediate layer / second light emitting unit / intermediate layer / third light emitting unit / cathode where the first light emitting unit , The second light emitting unit and the third light emitting unit may be the same or different. Further, two light emitting units may be the same, and the other one may be different.

  Further, the third light emitting unit may not be provided, and a light emitting unit or an intermediate layer may be further provided between the third light emitting unit and the electrode.

  The plurality of light emitting units may be directly laminated or may be laminated via an intermediate layer. The intermediate layer is generally composed of an intermediate electrode, an intermediate conductive layer, a charge generation layer, an electron extraction layer, a connection layer, and an intermediate layer. A known material and configuration may be used as long as the layer has a function of supplying electrons to the adjacent layer on the anode side and holes to the adjacent layer on the cathode side.

As a material used for the intermediate layer, for example, ITO (indium tin oxide), IZO (indium zinc oxide), ZnO ₂ , TiN, ZrN, HfN, TiOx, VOx, CuI, InN, GaN, CuAlO ₂ , CuGaO ₂ , SrCu ₂ O ₂ , LaB ₆ , RuO ₂ , Al and other conductive inorganic compound layers, Au / Bi ₂ O _{3 and} other two-layer films, SnO ₂ / Ag / SnO ₂ , ZnO / Ag / Multilayer films such as ZnO, Bi ₂ O ₃ / Au / Bi ₂ O ₃ , TiO ₂ / TiN / TiO ₂ , TiO ₂ / ZrN / TiO ₂ , fullerenes such as C ₆₀ , and conductive organic layers such as oligothiophene Examples include metal phthalocyanines, metal-free phthalocyanines, metalloporphyrins, and conductive organic compound layers such as metal-free porphyrins. The present invention is not limited to these.

  Preferred configurations in the light-emitting unit include, for example, the configurations (1) to (5) described in the above-described typical device configuration, except that the anode and the cathode are removed, but the present invention is not limited thereto. Not done.

  Specific examples of the tandem type organic EL device include, for example, US Pat. No. 6,337,492, US Pat. No. 7,420,203, US Pat. No. 7,473,923, US Pat. No. 6,872,472, US Pat. No. 6,107,734. Specification, U.S. Patent No. 6,337,492, International Publication No. 2005/009087, JP-A-2006-228712, JP-A-2006-24791, JP-A-2006-49393, and JP-A-2006-49394. JP-A-2006-49396, JP-A-2011-96679, JP-A-2005-340187, Patent No. 471424, Patent No. 3496681, Patent No. 3888564, Patent No. 421169, Patent No. 2010-192719 JP, JP-A-2009-076 29, JP-A-2008-078414, JP-A-2007-059848, JP-A-2003-272860, JP-A-2003-045676, International Publication No. 2005/094130, and the like. Although constituent materials and the like can be mentioned, the present invention is not limited to these.

  Hereinafter, each layer constituting the organic EL device of the present invention will be described.

<< Light-emitting layer >>
The light-emitting layer used in the present invention is a layer that provides a field in which electrons and holes injected from an electrode or an adjacent layer are recombined and emits light through excitons, and a light-emitting portion is formed in the light-emitting layer. It may be inside the layer or at the interface between the light emitting layer and the adjacent layer. The configuration of the light emitting layer used in the present invention is not particularly limited as long as it satisfies the requirements specified in the present invention.

  The total sum of the thicknesses of the light emitting layers is not particularly limited. However, the uniformity of the film to be formed, the prevention of applying an unnecessary high voltage at the time of light emission, and the improvement of the stability of the emission color with respect to the driving current are improved. From the viewpoint, it is preferably adjusted to a range of 2 nm to 5 μm, more preferably to a range of 2 to 500 nm, and still more preferably to a range of 5 to 200 nm.

  In the present invention, the thickness of each light emitting layer is preferably adjusted to a range of 2 nm to 1 μm, more preferably to a range of 2 to 200 nm, and still more preferably to a range of 3 to 150 nm. You.

  The light emitting layer used in the present invention preferably contains a light emitting dopant (also simply referred to as a dopant) and a host compound (a light emitting host, also simply referred to as a host).

(1) Light Emitting Dopant The light emitting dopant used in the present invention will be described.

  As the light emitting dopant, a phosphorescent light emitting dopant (also referred to as a phosphorescent dopant or a phosphorescent compound) and a fluorescent light emitting dopant (also referred to as a fluorescent dopant or a fluorescent compound) are preferably used. In the present invention, it is preferable that at least one light emitting layer contains a phosphorescent light emitting dopant.

  The concentration of the light-emitting dopant in the light-emitting layer can be arbitrarily determined based on the specific dopant used and the requirements of the device, and is contained at a uniform concentration in the thickness direction of the light-emitting layer. And may have an arbitrary concentration distribution.

  Further, the light emitting dopant used in the present invention may be used in combination of two or more kinds, and may be used in combination of dopants having different structures or in combination of a fluorescent light emitting dopant and a phosphorescent light emitting dopant. Thereby, an arbitrary luminescent color can be obtained.

  The emission color of the organic EL device of the present invention or the compound of the present invention is shown in FIG. 4.16 on page 108 of “New Edition of Color Science Handbook” (edited by The Japan Society of Color Science, Tokyo University Press, 1985). It is determined by the color when the result measured with CS-1000 (manufactured by Konica Minolta) is applied to the CIE chromaticity coordinates.

  In the present invention, it is also preferable that one or more light-emitting layers contain a plurality of light-emitting dopants having different emission colors and emit white light.

  There is no particular limitation on the combination of the light-emitting dopant that exhibits white, and examples thereof include a combination of blue and orange or a combination of blue, green, and red.

The white color in the organic EL device of the present invention is not particularly limited, and may be orange-colored white or blue-colored white. , The chromaticity in the CIE1931 color system at 1000 cd / m ² is preferably within the range of x = 0.39 ± 0.09 and y = 0.38 ± 0.08.

(1.1) Phosphorescent dopant The phosphorescent dopant (hereinafter, also referred to as “phosphorescent dopant”) used in the present invention will be described.

  The phosphorescent dopant used in the present invention is a compound in which light emission from an excited triplet is observed. Specifically, the phosphorescent dopant is a compound that emits phosphorescent light at room temperature (25 ° C.). The compound is defined as a compound of not less than 0.01 at 25 ° C., but the preferred phosphorescence quantum yield is not less than 0.1.

  The phosphorescence quantum yield can be measured by the method described in Spectroscopy II, 398, 4th edition, Experimental Chemistry Lecture 7, p. 398 (1992 edition, Maruzen). Although the phosphorescent quantum yield in a solution can be measured using various solvents, the phosphorescent dopant used in the present invention achieves the above-mentioned phosphorescent quantum yield (0.01 or more) in any of the solvents. Just do it.

  There are two types of light emission from phosphorescent dopants in principle.One is that the recombination of carriers occurs on the host compound where the carriers are transported, the excited state of the host compound is generated, and this energy is transferred to the phosphorescent dopant. This is an energy transfer type in which light emission is obtained from a phosphorescent dopant. The other is a carrier trap type in which a phosphorescent dopant serves as a carrier trap, and carriers recombine on the phosphorescent dopant to emit light from the phosphorescent dopant. In either case, the condition is that the excited state energy of the phosphorescent dopant is lower than the excited state energy of the host compound.

  The phosphorescent dopant that can be used in the present invention can be appropriately selected from known ones used for the light emitting layer of the organic EL device.

  Specific examples of known phosphorescent dopants that can be used in the present invention include compounds described in the following documents.

  Nature 395, 151 (1998), Appl. Phys. Lett. 78, 1622 (2001), Adv. Mater. 19, 739 (2007); Chem. Mater. 17, 3532 (2005), Adv. Mater. 17, 1059 (2005), WO 2009/100991, WO 2008/101842, WO 2003/040257, U.S. Patent Application Publication No. 2006/835469, U.S. Patent Application Publication 2006/2006. No. 0202194, U.S. Patent Application Publication No. 2007/0087321, U.S. Patent Application Publication No. 2005/02444673, Inorg. Chem. 40, 1704 (2001), Chem. Mater. 16, 2480 (2004), Adv. Mater. 16, 2003 (2004), Angew. Chem. lnt. Ed. 2006, 45, 7800, Appl. Phys. Lett. 86, 153505 (2005); Chem. Lett. 34, 592 (2005); Chem. Commun. 2906 (2005), Inorg. Chem. 42,1248 (2003), WO 2009/050290, WO 2002/015645, WO 2009/000673, U.S. Patent Application Publication No. 2002/0034656, U.S. Patent No. 7,332,232 U.S. Patent Application Publication No. 2009/0108737, U.S. Patent Application Publication No. 2009/0039776, U.S. Patent No. 6,921,915, U.S. Patent No. 6,687,266, U.S. Patent Application Publication No. 2007/0190359. Specification, U.S. Patent Application Publication No. 2006/0008670, U.S. Patent Application Publication No. 2009/0165846, U.S. Patent Application Publication No. 2008/0015355, U.S. Patent No. 7,250,226, U.S. Patent No. No. 7396598 , U.S. Patent Application Publication No. 2006/0263635, U.S. Patent Application Publication No. 2003/0138657, U.S. Patent Application Publication No. 2003/0152802, U.S. Patent No. 7090928, Angew. Chem. lnt. Ed. 47, 1 (2008), Chem. Mater. 18, 5119 (2006), Inorg. Chem. 46, 4308 (2007), Organometallics 23, 3745 (2004), Appl. Phys. Lett. 74,1361 (1999), International Publication No. 2002/002714, International Publication No. 2006/009024, International Publication No. 2006/056418, International Publication No. 2005/0193373, International Publication No. 2005/123873, International Publication No. 2005/123873, WO 2007/004380, WO 2006/082742, U.S. Patent Application Publication No. 2006/0251923, U.S. Patent Application Publication No. 2005/0260441, U.S. Patent No. 7393599. Specification, U.S. Patent No. 7,534,505, U.S. Patent No. 7,445,855, U.S. Patent Application Publication No. 2007/0190359, U.S. Patent Application Publication No. 2008/0297033, U.S. Patent No. 7,338,722 , US special Patent Application Publication No. 2002/0134984, U.S. Patent No. 7,279,704, U.S. Patent Application Publication No. 2006/098120, U.S. Patent Application Publication No. 2006/103874, International Publication No. 2005/076380, WO 2010/032663, WO 2008/140115, WO 2007/052431, WO 2011/134013, WO 2011/157339, WO 2010/086089, WO 2009/113646, International Publication No. 2012/020327, International Publication No. 2011/051404, International Publication No. 2011/004639, International Publication No. 2011/073149, US Patent Application Publication No. 2012/228584, USA Patent Application Publication No. 2012/212126, JP-A-2012-069737, JP-A-2012-195554, JP-A-2009-114086, JP-A-2003-81988, JP-A-2002-302671 And JP-A-2002-363552.

  Among them, preferred phosphorescent dopants include organometallic complexes having Ir as a central metal. More preferably, a complex containing at least one coordination mode of a metal-carbon bond, a metal-nitrogen bond, a metal-oxygen bond, and a metal-sulfur bond is preferable.

(1.2) Fluorescent dopant The fluorescent dopant (hereinafter, also referred to as “fluorescent dopant”) used in the present invention will be described.

  The fluorescent dopant used in the present invention is a compound capable of emitting light from an excited singlet, and is not particularly limited as long as emission from an excited singlet is observed.

  Examples of the fluorescent dopant used in the present invention include, for example, anthracene derivative, pyrene derivative, chrysene derivative, fluoranthene derivative, perylene derivative, fluorene derivative, arylacetylene derivative, styrylarylene derivative, styrylamine derivative, arylamine derivative, boron complex, coumarin Derivatives, pyran derivatives, cyanine derivatives, croconium derivatives, squarium derivatives, oxobenzanthracene derivatives, fluorescein derivatives, rhodamine derivatives, pyrylium derivatives, perylene derivatives, polythiophene derivatives, rare earth complex compounds, and the like.

  In recent years, light emitting dopants utilizing delayed fluorescence have been developed, and these may be used.

  Specific examples of the luminescent dopant utilizing delayed fluorescence include, for example, compounds described in International Publication No. 2011/156793, JP-A-2011-213643, JP-A-2010-93181, and the like. Is not limited to these.

(2) Host Compound The host compound used in the present invention is a compound mainly responsible for charge injection and transport in the light emitting layer, and substantially no light emission of the organic EL element itself is observed.

  Preferably, the compound has a phosphorescence quantum yield of phosphorescence emission of less than 0.1 at room temperature (25 ° C.), more preferably a compound having a phosphorescence quantum yield of less than 0.01. In addition, among the compounds contained in the light emitting layer, the mass ratio in the layer is preferably 20% or more.

  Further, the excited state energy of the host compound is preferably higher than the excited state energy of the light emitting dopant contained in the same layer.

  The host compounds may be used alone or in combination of two or more. By using a plurality of types of host compounds, it is possible to adjust the transfer of electric charge, and the efficiency of light emission of the organic EL element can be increased.

  The host compound that can be used in the present invention is not particularly limited, and a compound conventionally used in an organic EL device can be used. It may be a low molecular compound or a high molecular compound having a repeating unit, or a compound having a reactive group such as a vinyl group or an epoxy group.

  As a known host compound, it has a hole-transporting ability or an electron-transporting ability, prevents a long wavelength of light emission, and furthermore, stabilizes the organic EL element against heat generation during driving at a high temperature or during driving of the element. From the viewpoint of operating at high temperature, it is preferable to have a high glass transition temperature (Tg). Preferably, Tg is 90 ° C or higher, more preferably 120 ° C or higher.

  Here, the glass transition point (Tg) is a value (temperature) determined by a method according to JIS-K-7121 using DSC (Differential Scanning Colorimetry).

  Specific examples of known host compounds used in the organic EL device of the present invention include, but are not limited to, compounds described in the following documents.

  JP-A-2001-257076, JP-A-2002-308855, JP-A-2001-313179, JP-A-2002-319492, JP-A-2001-357977, JP-A-2002-334786, JP-A-2002-8860, JP-A-2002-334787, JP-A-2002-15871, JP-A-2002-334788, JP-A-2002-43056, JP-A-2002-334789, JP-A-2002-75645, JP-A-2002-338579, and JP-A-2002-338579. JP-A-2002-105445, JP-A-2002-343568, JP-A-2002-141173, JP-A-2002-352957, JP-A-2002-203683, JP-A-2002-363227, JP-A-2002-231453, and JP-A-2002-231453. No. 003-3165, No. 2002-234888, No. 2003-27048, No. 2002-255934, No. 2002-260861, No. 2002-280183, No. 2002-299060, No. 2002 JP-A-302516, JP-A-2002-305083, JP-A-2002-305084, JP-A-2002-308837, U.S. Patent Application Publication No. 2003/0175555, U.S. Patent Application Publication No. 2006/0280965, U.S. Patent Application Publication No. 2005/0112407, U.S. Patent Application Publication No. 2009/0017330, U.S. Patent Application Publication No. 2009/0030202, U.S. Patent Publication No. 2005/0238919, International Publication No. 20 1/039234, WO 2009/021126, WO 2008/056746, WO 2004/093207, WO 2005/089025, WO 2007/063796, WO 2007/073796. WO / 063754, WO 2004/107822, WO 2005/030900, WO 2006/114966, WO 2009/086028, WO 2009/003898, WO 2012/023947. JP-A-2008-074939, JP-A-2007-254297, and EP2034538.

《Electron transport layer》
In the present invention, the electron transport layer may be made of a material having a function of transporting electrons, and may have a function of transmitting electrons injected from the cathode to the light emitting layer.

  The total thickness of the electron transporting layer used in the present invention is not particularly limited, but is usually in the range of 2 nm to 5 μm, more preferably 2 to 500 nm, and still more preferably 5 to 200 nm.

  In an organic EL device, when light generated in a light emitting layer is extracted from an electrode, light extracted directly from the light emitting layer and light extracted after being reflected by an electrode for extracting light and an electrode located on a counter electrode interfere with each other. It is known to cause. In the case where light is reflected by the cathode, the interference effect can be used efficiently by appropriately adjusting the total thickness of the electron transport layer between 5 nm and 1 μm.

On the other hand, if the layer thickness of the electron transport layer is increased, the voltage is likely to increase. Therefore, particularly when the layer thickness is large, the electron mobility of the electron transport layer is preferably 10 ⁻⁵ cm ² / Vs or more. .

  The material used for the electron transport layer (hereinafter, referred to as an electron transport material) may have any of an electron injecting or transporting property and a hole blocking property, and may be any of conventionally known compounds. Can be selected and used.

  For example, nitrogen-containing aromatic heterocyclic derivatives (carbazole derivatives, azacarbazole derivatives (where one or more carbon atoms constituting the carbazole ring are substituted with nitrogen atoms), pyridine derivatives, pyrimidine derivatives, pyrazine derivatives, pyridazine derivatives, Triazine derivatives, quinoline derivatives, quinoxaline derivatives, phenanthroline derivatives, azatriphenylene derivatives, oxazole derivatives, thiazole derivatives, oxadiazole derivatives, thiadiazole derivatives, triazole derivatives, benzimidazole derivatives, benzoxazole derivatives, benzothiazole derivatives, etc.), dibenzofuran derivatives, Examples include dibenzothiophene derivatives, silole derivatives, aromatic hydrocarbon ring derivatives (naphthalene derivatives, anthracene derivatives, triphenylene, etc.).

  Further, metal complexes having a quinolinol skeleton or a dibenzoquinolinol skeleton as a ligand, for example, tris (8-quinolinol) aluminum (Alq), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7- Dibromo-8-quinolinol) aluminum, tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), and the like, A metal complex in which the central metal is replaced with In, Mg, Cu, Ca, Sn, Ga or Pb can also be used as the electron transport material.

  In addition, metal-free or metal phthalocyanine, or those whose terminals are substituted with an alkyl group, a sulfonic acid group, or the like can be preferably used as the electron transporting material. Further, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as the electron transporting material, and an inorganic semiconductor such as n-type Si or n-type SiC like the hole injection layer and the hole transport layer. Can also be used as an electron transport material.

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

  In the electron transport layer used in the present invention, the electron transport layer may be doped with a dopant as a guest material to form an electron transport layer having a high n property (electron rich). Examples of the doping material include n-type dopants such as metal compounds such as metal complexes and metal halides. Specific examples of the electron transport layer having such a configuration include, for example, JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, JP-A-2001-102175, and J.P. Appl. Phys. , 95, 5773 (2004).

  Specific examples of known and preferred electron transport materials used in the organic EL device of the present invention include, but are not limited to, compounds described in the following documents.

  U.S. Patent No. 6,528,187, U.S. Patent No. 7,230,107, U.S. Patent Application Publication No. 2005/0025993, U.S. Patent Application Publication No. 2004/0036077, U.S. Patent Application Publication No. 2009/0115316 US Patent Application Publication No. 2009/0101870, US Patent Application Publication No. 2009/0179554, International Publication No. 2003/060956, International Publication No. 2008/132805, Appl. Phys. Lett. 75, 4 (1999), Appl. Phys. Lett. 79, 449 (2001), Appl. Phys. Lett. 81, 162 (2002), Appl. Phys. Lett. 81, 162 (2002), Appl. Phys. Lett. 79,156 (2001), U.S. Patent No. 7,964,293, U.S. Patent Application Publication No. 2009/030202, International Publication No. 2004/080975, International Publication No. 2004/063159, International Publication No. 2005/085387. WO 2006/067931, WO 2007/086552, WO 2008/114690, WO 2009/069442, WO 2009/066779, WO 2009/054253, International WO 2011/086935, WO 2010/150593, WO 2010/047707, EP 231826, JP 2010-251675, JP 2009-209133, JP 2009 −1241 4, JP-A-2008-277810, JP-A-2006-156445, JP-A-2005-340122, JP-A-2003-45662, JP-A-2003-31367, and JP-A-2003-282270. Gazette, WO 2012/115034, and the like.

  More preferable electron transport materials in the present invention include pyridine derivatives, pyrimidine derivatives, pyrazine derivatives, triazine derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, carbazole derivatives, azacarbazole derivatives, and benzimidazole derivatives.

  The electron transport material may be used alone or in combination of two or more.

《Hole blocking layer》
The hole blocking layer is a layer having a function of an electron transporting layer in a broad sense, and is preferably made of a material having a function of transporting electrons and having a small ability to transport holes. , The probability of recombination of electrons and holes can be improved.

  Further, the above-described structure of the electron transporting layer can be used as a hole blocking layer according to the present invention, if necessary.

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

  The thickness of the hole blocking layer used in the present invention is preferably in the range of 3 to 100 nm, and more preferably in the range of 5 to 30 nm.

  As the material used for the hole blocking layer, the material used for the above-described electron transport layer is preferably used, and the material used for the above-described host compound is also preferably used for the hole blocking layer.

《Electron injection layer》
The electron injection layer (also referred to as a “cathode buffer layer”) used in the present invention is a layer provided between a cathode and a light emitting layer for lowering driving voltage and improving light emission luminance. It is described in detail in Vol. 2, Chapter 2, "Electrode Materials" (pages 123 to 166) of the Industrialization Frontier (published by NTT Corporation on November 30, 1998).

  In the present invention, an electron injection layer may be provided as necessary, and may be present between the cathode and the light emitting layer or between the cathode and the electron transport layer as described above.

  The electron injection layer is preferably a very thin film, and its thickness is preferably in the range of 0.1 to 5 nm depending on the material. Further, the film may be a non-uniform film in which the constituent material is intermittent.

  The details of the electron injection layer are also described in JP-A-6-325871, JP-A-9-17574, and JP-A-10-74586. Specific examples of materials preferably used for the electron injection layer include: , Metals such as strontium and aluminum, alkali metal compounds such as lithium fluoride, sodium fluoride, and potassium fluoride; alkaline earth metal compounds such as magnesium fluoride and calcium fluoride; Examples include metal oxides represented by aluminum, metal complexes represented by lithium 8-hydroxyquinolate (Liq), and the like. Further, the above-described electron transport material can be used.

  The materials used for the electron injection layer may be used alone or in combination of two or more.

《Hole transport layer》
In the present invention, the hole transport layer may be made of a material having a function of transporting holes, and may have a function of transmitting holes injected from the anode to the light emitting layer.

  The total thickness of the hole transport layer used in the present invention is not particularly limited, but is usually in the range of 5 nm to 5 μm, more preferably 2 to 500 nm, and still more preferably 5 nm to 200 nm.

  The material used for the hole transporting layer (hereinafter, referred to as a hole transporting material) may have any of a hole injecting or transporting property and an electron barrier property. Any one can be selected from and used.

  For example, porphyrin derivatives, phthalocyanine derivatives, oxazole derivatives, oxadiazole derivatives, triazole derivatives, imidazole derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, hydrazone derivatives, stilbene derivatives, polyarylalkane derivatives, triarylamine derivatives, carbazole derivatives , Indolocarbazole derivatives, isoindole derivatives, acene derivatives such as anthracene and naphthalene, fluorene derivatives, fluorenone derivatives, polyvinylcarbazole, polymer materials or oligomers having aromatic amines introduced into the main chain or side chain, polysilane, conductive Polymer or oligomer (for example, PEDOT: PSS, aniline-based copolymer, polyaniline, polythiophene, etc.).

  Examples of the triarylamine derivative include a benzidine type represented by αNPD, a star burst type represented by MTDATA, and a compound having fluorene or anthracene in a triarylamine-linked core portion.

  Further, a hexaazatriphenylene derivative described in JP-T-2003-519432, JP-A-2006-135145, or the like can also be used as a hole transport material.

  Further, a hole transporting layer having a high p property and doped with an impurity may be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, JP-A-2001-102175, and J.P. Appl. Phys. , 95, 5773 (2004).

Also, JP-A-11-251067, J.P. Huang et. al. A so-called p-type hole transporting material or an inorganic compound such as p-type-Si or p-type-SiC as described in a written reference (Applied Physics Letters 80 (2002), p. 139) can also be used. Further, an orthometalated organometallic complex having Ir or Pt as a central metal such as Ir (ppy) ₃ is also preferably used.

  As the hole transporting material, those described above can be used, but a triarylamine derivative, a carbazole derivative, an indolocarbazole derivative, an azatriphenylene derivative, an organometallic complex, or an aromatic amine is introduced into a main chain or a side chain. Polymer materials or oligomers are preferably used.

  Specific examples of known preferable hole transporting materials used for the organic EL device of the present invention include, but are not limited to, the compounds described in the following documents in addition to the above-mentioned documents.

  For example, Appl. Phys. Lett. 69, 2160 (1996); Lumin. 72-74, 985 (1997), Appl. Phys. Lett. 78, 673 (2001), Appl. Phys. Lett. 90, 183503 (2007), Appl. Phys. Lett. 90, 183503 (2007), Appl. Phys. Lett. 51, 913 (1987), Synth. Met. 87, 171 (1997), Synth. Met. 91, 209 (1997), Synth. Met. 111, 421 (2000); SID Symposium Digest, 37, 923 (2006); Mater. Chem. 3,319 (1993), Adv. Mater. 6,677 (1994), Chem. Mater. 15,3148 (2003), U.S. Patent Application Publication No. 2003/0162053, U.S. Patent Application Publication No. 2002/0158242, U.S. Patent Application Publication No. 2006/02420279, U.S. Patent Application Publication No. 2008 / No. 0220265, U.S. Pat. No. 5,061,569, International Publication No. 2007/002683, International Publication No. 2009/018809, European Patent No. 6509555, U.S. Patent Application Publication No. 2008/0124572, United States Patent Application Publication No. 2007/0278938, U.S. Patent Application Publication No. 2008/0106190, U.S. Patent Application Publication No. 2008/0018221, International Publication No. 2012/115034, Japanese Patent Application Publication No. 2003-519432. JP-A-2006- 35145 JP is US Patent Application No. 13/585981 Patent like.

  The hole transporting material may be used alone or in combination of two or more.

《Electron blocking layer》
By providing an electron blocking layer, electrons are blocked while transporting holes, so that the recombination probability of electrons and holes can be improved.

  The electron blocking layer provided in the organic EL device of the present invention is preferably provided adjacent to the light emitting layer on the anode side.

  The thickness of the electron blocking layer used in the present invention is preferably in the range of 3 to 100 nm, and more preferably in the range of 5 to 30 nm.

  As the material used for the electron blocking layer, the material used for the hole transport layer described above is preferably used, and the material used for the host compound described above is also preferably used for the electron blocking layer.

《Hole injection layer》
The hole injection layer (also referred to as an “anode buffer layer”) used in the present invention is a layer provided between an anode and a light emitting layer for lowering driving voltage and improving light emission luminance. And its industrialization frontier (published by NTTS on November 30, 1998), Vol. 2, Chapter 2, "Electrode Materials" (pages 123 to 166).

  In the present invention, the hole injection layer may be provided as necessary, and may be present between the anode and the light emitting layer or between the anode and the hole transport layer as described above.

  The details of the hole injection layer are also described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069, and the like. As a material used for the hole injection layer, for example, The materials used for the above-described hole transport layer are exemplified.

  Above all, phthalocyanine derivatives represented by copper phthalocyanine, hexaazatriphenylene derivatives described in JP-T-2003-519432 and JP-A-2006-135145, metal oxides represented by vanadium oxide, amorphous carbon And conductive polymers such as polyaniline (emeraldine) and polythiophene; ortho-metalated complexes represented by tris (2-phenylpyridine) iridium complex; and triarylamine derivatives.

  The materials used for the hole injection layer described above may be used alone or in combination of two or more.

《Inclusions》
The above-mentioned organic layer in the present invention may further contain other inclusions.

  Examples of the inclusion include halogen elements such as bromine, iodine and chlorine, halogenated compounds, alkali metal and alkaline earth metals such as Pd, Ca, and Na, and transition metal compounds, complexes, and salts.

  The content of the content can be arbitrarily determined, but is preferably 1000 ppm or less, more preferably 500 ppm or less, and still more preferably 50 ppm or less based on the total mass% of the contained layer. .

  However, it is not within this range depending on the purpose of improving the transportability of electrons and holes, the purpose of making the energy transfer of excitons advantageous, and the like.

《Method of forming organic layer》
A method for forming an organic layer (a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, etc.) used in the present invention will be described.

  The method for forming the organic layer used in the present invention is not particularly limited, and a conventionally known method such as a vacuum deposition method or a wet method (also referred to as a wet process) can be used. Here, the organic layer is preferably a layer formed by a wet process. That is, it is preferable to manufacture an organic EL element by a wet process. By manufacturing an organic EL element by a wet process, it is possible to obtain effects such as easy formation of a uniform film (coating film) and hardly generating pinholes. Here, the film (coating film) is a film that has been dried after being applied by a wet process.

  Examples of the wet method include a spin coating method, a casting method, an inkjet method, a printing method, a die coating method, a blade coating method, a roll coating method, a spray coating method, a curtain coating method, an LB method (Langmuir-Blodgett method), and the like. From the viewpoint of easily obtaining a uniform thin film and high productivity, a method having high suitability for a roll-to-roll method such as a die coating method, a roll coating method, an ink jet method, and a spray coating method is preferable.

  Examples of the liquid medium in which the organic EL material according to the present invention is dissolved or dispersed include ketones such as methyl ethyl ketone and cyclohexanone, fatty acid esters such as ethyl acetate, halogenated hydrocarbons such as dichlorobenzene, toluene, xylene, and mesitylene. And aromatic hydrocarbons such as cyclohexylbenzene, aliphatic hydrocarbons such as cyclohexane, decalin and dodecane, and organic solvents such as N, N-dimethylformamide (DMF) and dimethylsulfoxide (DMSO).

  In addition, as a dispersing method, dispersing can be performed by a dispersing method such as ultrasonic wave, high shearing force dispersion, and media dispersion.

Further, a different film forming method may be applied to each layer. When a vapor deposition method is employed for film formation, the vapor deposition conditions vary depending on the type of compound used, etc., but generally, the boat heating temperature is 50 to 450 ° C., the degree of vacuum is 10 ⁻⁶ to 10 ⁻² Pa, and the vapor deposition rate is 0.01 to It is desirable to appropriately select 50 nm / sec, a substrate temperature of −50 to 300 ° C., a thickness of 0.1 nm to 5 μm, preferably 5 to 200 nm.

  In the formation of the organic layer used in the present invention, it is preferable that the hole injection layer to the cathode are formed consistently by a single evacuation, but the film may be taken out in the middle and subjected to a different film forming method. In that case, it is preferable to perform the operation in a dry inert gas atmosphere.

"anode"
As the anode in the organic EL element, a metal, an alloy, an electrically conductive compound, or a mixture thereof having a large work function (4 eV or more, preferably 4.5 V or more) as an electrode material is preferably used. Specific examples of such an electrode substance include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ , and ZnO. Alternatively, a material such as IDIXO (In ₂ O ₃ —ZnO) that can form an amorphous and transparent conductive film may be used.

  The anode may be formed into a thin film by a method such as vapor deposition or sputtering of these electrode substances, and a pattern having a desired shape may be formed by a photolithography method, or when a pattern precision is not so required (about 100 μm or more). Alternatively, a pattern may be formed through a mask having a desired shape at the time of vapor deposition or sputtering of the electrode material.

  Alternatively, when a substance that can be applied such as an organic conductive compound is used, a wet film forming method such as a printing method and a coating method can be used. When light is extracted from the anode, the transmittance is desirably greater than 10%, and the sheet resistance of the anode is preferably several hundred Ω / □ or less.

  The thickness of the anode depends on the material, but is usually selected in the range of 10 nm to 1 μm, preferably 10 to 200 nm.

"cathode"
As the cathode, a material having a low work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof is used. Specific examples of such an electrode material include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O) ₃ ) Mixtures, indium, lithium / aluminum mixtures, aluminum, rare earth metals and the like. Among them, a mixture of an electron-injecting metal and a second metal that is a stable metal having a large work function value, such as a magnesium / silver mixture, from the viewpoint of durability against electron injection and oxidation. Preferred are a magnesium / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide (Al ₂ O ₃ ) mixture, a lithium / aluminum mixture, aluminum and the like.

  The cathode can be manufactured by forming a thin film from these electrode substances by a method such as evaporation or sputtering. Further, the sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 to 200 nm.

  In order to transmit emitted light, it is convenient if either the anode or the cathode of the organic EL element is transparent or translucent to increase the emission luminance.

  Further, after the metal is formed in the cathode in a thickness of 1 to 20 nm, a transparent or translucent cathode can be manufactured by manufacturing a conductive transparent material described in the description of the anode thereon. By applying the method, an element in which both the anode and the cathode have transparency can be manufactured.

《Support substrate》
The support substrate (hereinafter, also referred to as a substrate, a substrate, a substrate, a support, or the like) that can be used for the organic EL device of the present invention is not particularly limited in the type of glass, plastic, and the like, and is transparent. May also be opaque. When light is extracted from the support substrate side, the support substrate is preferably transparent. Preferred examples of the transparent support substrate include glass, quartz, and a transparent resin film. A particularly preferred supporting substrate is a resin film capable of giving flexibility to the organic EL element.

  Examples of the resin film include polyester such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate (TAC), cellulose acetate butyrate, and cellulose acetate propionate ( CAP), cellulose esters such as cellulose acetate phthalate and cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyetherketone, polyimide , Polyether sulfone (PES), polyphenylene sulfide, polysulfones, Cycloether-based resins such as reetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic, or polyarylate, ARTON (trade name, manufactured by JSR) or Apel (trade name, manufactured by Mitsui Chemicals, Inc.) And the like.

An inorganic or organic coating or a hybrid coating of both may be formed on the surface of the resin film, and the water vapor permeability (25 ± 0.5 ° C.) measured by a method according to JIS K 7129-1992. And a barrier film having a relative humidity (90 ± 2)% RH of 0.01 g / (m ² · 24 h) or less, and furthermore, oxygen measured by a method according to JIS K 7126-1987. It is preferable that the high barrier film has a permeability of 10 ⁻³ ml / (m ² · 24 h · atm) or less and a water vapor permeability of 10 ⁻⁵ g / (m ² · 24 h) or less.

  As a material for forming the barrier film, any material that causes deterioration of the element such as moisture or oxygen and has a function of suppressing intrusion may be used. For example, silicon oxide, silicon dioxide, silicon nitride, or the like can be used. Further, in order to improve the brittleness of the film, it is more preferable to have a laminated structure of these inorganic layers and a layer made of an organic material. The order of laminating the inorganic layer and the organic layer is not particularly limited, but it is preferable that both are alternately laminated plural times.

  There is no particular limitation on the method for forming the barrier film, and examples thereof include a vacuum deposition method, a sputtering method, a reactive sputtering method, a molecular beam epitaxy method, a cluster ion beam method, an ion plating method, a plasma polymerization method, and an atmospheric pressure plasma polymerization method. , A plasma CVD method, a laser CVD method, a thermal CVD method, a coating method and the like can be used, and a method using an atmospheric pressure plasma polymerization method as described in JP-A-2004-68143 is particularly preferable.

  Examples of the opaque support substrate include a metal plate such as aluminum and stainless steel, a film, an opaque resin substrate, and a ceramic substrate.

  The external quantum efficiency at room temperature of light emission of the organic EL device of the present invention is preferably 1% or more, more preferably 5% or more.

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

  Further, a hue improving filter such as a color filter or the like may be used in combination, or a color conversion filter for converting the emission color of the organic EL element into multiple colors using a phosphor may be used in combination.

《Sealing》
Examples of the sealing means used for sealing the organic EL element of the present invention include a method of bonding a sealing member, an electrode, and a support substrate with an adhesive. The sealing member may be disposed so as to cover the display area of the organic EL element, and may have a concave plate shape or a flat plate shape. In addition, transparency and electrical insulation are not particularly limited.

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

In the present invention, a polymer film or a metal film can be preferably used because the organic EL element can be thinned. Furthermore, the polymer film JIS K 7126-1987 oxygen permeability measured by the method conforming to the ^{1 × 10 -3 ml / (m} 2 · 24h · atm) or less, by a method according to JIS K 7129-1992 the measured water vapor transmission rate (25 ± 0.5 ° C., relative humidity (90 ± 2)%) is preferably that of ^{1 × 10 -3 g / (m} 2 · 24h) or less.

  To process the sealing member into a concave shape, sand blasting, chemical etching, or the like is used.

  Specific examples of the adhesive include an acrylic acid-based oligomer, a photocurable and thermosetting adhesive having a reactive vinyl group of a methacrylic acid-based oligomer, and a moisture-curable adhesive such as 2-cyanoacrylate. be able to. Further, a heat and chemical curing type (two-liquid mixing) of an epoxy type or the like can be used. In addition, hot melt type polyamide, polyester, and polyolefin can be used. In addition, a cation-curable ultraviolet-curable epoxy resin adhesive can be used.

  In addition, since the organic EL element may be deteriorated by the heat treatment, it is preferable that the organic EL element can be adhesively cured from room temperature to 80 ° C. Further, a desiccant may be dispersed in the adhesive. A commercially available dispenser may be used for applying the adhesive to the sealing portion, or printing may be performed like screen printing.

  In addition, it is also preferable to form an encapsulating film by coating the electrode and the organic layer on the outside of the electrode on the side facing the support substrate with the organic layer interposed therebetween, and forming an inorganic or organic material layer in contact with the support substrate. . In this case, as a material for forming the film, any material may be used as long as it has a function of suppressing intrusion of elements such as moisture and oxygen which cause deterioration of the element, for example, silicon oxide, silicon dioxide, silicon nitride, and the like. it can.

  In order to further improve the brittleness of the film, it is preferable to have a laminated structure of these inorganic layers and a layer made of an organic material. The method for forming these films is not particularly limited, and examples thereof include a vacuum deposition method, a sputtering method, a reactive sputtering method, a molecular beam epitaxy method, a cluster ion beam method, an ion plating method, a plasma polymerization method, and an atmospheric pressure plasma pressure method. A legal method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used.

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

  Examples of the hygroscopic compound include metal oxides (eg, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide, etc.) and sulfates (eg, sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate) Etc.), metal halides (eg, calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide, etc.), perchloric acids (eg, perchloric acid) Barium, magnesium perchlorate, etc.), and sulfates, metal halides and perchloric acids are preferably anhydrous salts.

《Protective film, protective plate》
A protective film or a protective plate may be provided outside the sealing film or the sealing film on the side facing the support substrate with the organic layer interposed therebetween in order to increase the mechanical strength of the element. In particular, when the sealing is performed by the sealing film, the mechanical strength is not always high, and thus it is preferable to provide such a protective film and a protective plate. As a material that can be used for this, a glass plate, a polymer plate, a metal plate, and the like similar to those used for the sealing can be used, but a polymer film is used because it is lightweight and thin. preferable.

《Light extraction enhancement technology》
The organic electroluminescent element emits light inside a layer having a refractive index higher than that of air (with a refractive index of about 1.6 to 2.1), and about 15% to about 20% of light generated in the light emitting layer. It is generally said that only light can be extracted. This is because light incident on the interface (interface between the transparent substrate and air) at an angle θ equal to or larger than the critical angle causes total reflection and cannot be taken out of the device. This is because light causes total reflection between the light emitting devices and the light propagates through the transparent electrode or the light emitting layer, and as a result, the light escapes toward the side surface of the device.

  As a method for improving the light extraction efficiency, for example, a method of forming irregularities on the surface of a transparent substrate to prevent total reflection at the interface between the transparent substrate and air (for example, US Pat. No. 4,774,435), A method of improving efficiency by imparting light condensing property (for example, JP-A-63-31479), a method of forming a reflection surface on a side surface of an element or the like (for example, JP-A-1-220394), A flat layer having an intermediate refractive index between the substrate and the luminous body to form an anti-reflection film (for example, JP-A-62-172691). (For example, Japanese Unexamined Patent Application Publication No. 2001-202827), a method of forming a diffraction grating between any of the substrates, the transparent electrode layer and the light emitting layer (including between the substrate and the outside) ( JP 11 JP), etc. 283751 can be mentioned.

  In the present invention, these methods can be used in combination with the organic EL element of the present invention. However, a method of introducing a flat layer having a lower refractive index than the substrate between the substrate and the light-emitting body, or a method of introducing the substrate into a transparent layer A method of forming a diffraction grating between any of the electrode layers and the light emitting layer (including between the substrate and the outside world) can be suitably used.

  In the present invention, by combining these means, it is possible to obtain an element having higher luminance and more excellent durability.

  When a medium with a low refractive index is formed between the transparent electrode and the transparent substrate with a thickness longer than the wavelength of light, the light emitted from the transparent electrode has a higher extraction efficiency to the outside as the refractive index of the medium is lower. Become.

  Examples of the low refractive index layer include aerogel, porous silica, magnesium fluoride, and a fluorine-based polymer. Since the refractive index of the transparent substrate is generally in the range of about 1.5 to 1.7, the low refractive index layer preferably has a refractive index of about 1.5 or less. Further, it is more preferably 1.35 or less.

  Further, the thickness of the low refractive index medium is desirably at least twice the wavelength in the medium. This is because the effect of the low-refractive-index layer is reduced when the thickness of the low-refractive-index medium is approximately equal to the wavelength of light and the thickness of the layer into which the evanescently transmitted electromagnetic waves enter the substrate.

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

  The diffraction grating to be introduced preferably has a two-dimensional periodic refractive index. This is because light emitted from the light-emitting layer is randomly generated in all directions, so a general one-dimensional diffraction grating having a periodic refractive index distribution only in a certain direction diffracts only light traveling in a specific direction. However, the light extraction efficiency does not increase so much.

  However, by making the refractive index distribution a two-dimensional distribution, light traveling in all directions is diffracted, and the light extraction efficiency increases.

  The position where the diffraction grating is introduced may be between any layers or in a medium (in a transparent substrate or a transparent electrode), but is preferably in the vicinity of the organic light emitting layer where light is generated. At this time, the period of the diffraction grating is preferably in the range of about 1/2 to 3 times the wavelength of light in the medium. The arrangement of the diffraction grating is preferably two-dimensionally repeated, such as a square lattice, a triangular lattice, or a honeycomb lattice.

《Light collecting sheet》
The organic EL device of the present invention is processed in such a manner that a structure on a microlens array is provided on the light extraction side of a support substrate (substrate), or is combined with a so-called light-collecting sheet, so that the organic EL device is in a specific direction, By condensing light in the front direction with respect to the light emitting surface, the luminance in a specific direction can be increased.

  As an example of the microlens array, quadrangular pyramids having a side of 30 μm and an apex angle of 90 degrees are two-dimensionally arranged on the light extraction side of the substrate. One side is preferably in the range of 10 to 100 μm. If it is smaller than this, the effect of diffraction occurs and coloring occurs, and if it is too large, the thickness becomes undesirably thick.

  As the condensing sheet, for example, a sheet practically used in an LED backlight of a liquid crystal display device can be used. As such a sheet, for example, a brightness enhancement film (BEF) manufactured by Sumitomo 3M Limited can be used. The shape of the prism sheet may be, for example, a substrate in which a の -shaped stripe having an apex angle of 90 degrees and a pitch of 50 μm is formed, or a shape in which the apex angle is rounded and the pitch is randomly changed. Shape or other shapes.

  Further, a light diffusing plate / film may be used in combination with the light-condensing sheet in order to control the light emission angle from the organic EL element. For example, a diffusion film (light-up) manufactured by Kimoto Co., Ltd. can be used.

《Applications》
The organic EL element of the present invention can be used as a display device, a display, and various light emission light sources.

  Examples of light emitting light sources include lighting devices (home lighting, car interior lighting), clocks and backlights for LCDs, signboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copiers, light sources for optical communication processors, and light sources. Examples include a light source of a sensor, but the present invention is not limited thereto. In particular, the light source can be effectively used for a backlight or a light source for illumination of a liquid crystal display device.

  In the organic EL device of the present invention, patterning may be performed by a metal mask, an inkjet printing method, or the like during film formation, if necessary. When patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or all the layers of the element may be patterned. In the production of the element, a conventionally known method is used. Can be.

《Display device》
One embodiment of the display device of the present invention including the organic EL element of the present invention will be described. Hereinafter, an example of a display device having the organic EL element of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic perspective view showing an example of the configuration of a display device provided with the organic EL element of the present invention, and displays image information by emitting light from the organic EL element. It is a schematic diagram. As shown in FIG. 1, the display 1 includes a display unit A having a plurality of pixels, a control unit B for performing image scanning of the display unit A based on image information, and the like.

  The control unit B is electrically connected to the display unit A. The control unit B sends a scanning signal and an image data signal to each of the plurality of pixels based on external image information. As a result, each pixel sequentially emits light according to the image data signal for each scanning line by the scanning signal, and the image information is displayed on the display unit A.

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

  The display section A has a wiring section including a plurality of scanning lines 5 and data lines 6 and a plurality of pixels 3 on a substrate.

  The main members of the display unit A will be described below.

  FIG. 2 shows a case where the light emitted from the pixel 3 is extracted in the white arrow direction (downward). The scanning lines 5 and the plurality of data lines 6 of the wiring portion are each made of a conductive material. The scanning lines 5 and the data lines 6 are orthogonal to each other in a grid pattern, and are connected to the pixels 3 at orthogonal positions (details are not shown).

  When the scanning signal is transmitted from the scanning line 5, the pixel 3 receives the image data signal from the data line 6, and emits light in accordance with the received image data.

  By arranging pixels in a red region, pixels in a green region, and pixels in a blue region with appropriate colors in parallel on the same substrate, a full-color display is possible.

《Lighting device》
One mode of the lighting device of the present invention including the organic EL element of the present invention will be described.

  The non-light-emitting surface of the organic EL device of the present invention is covered with a glass case, and a 300 μm-thick glass substrate is used as a sealing substrate, and an epoxy-based photocurable adhesive (Lux made by Toagosei Co., Ltd.) Track LC0629B) is applied, is placed on the cathode, is brought into close contact with the transparent support substrate, is irradiated with UV light from the glass substrate side, is cured and is sealed, and is illuminated as shown in FIGS. Can be formed.

  FIG. 3 is a schematic view of a lighting device, in which an organic EL element 101 of the present invention is covered with a glass cover 102 (in the sealing operation with the glass cover 102, the organic EL element 101 is brought into contact with the atmosphere. Without using a glove box under a nitrogen atmosphere (in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more).)

  FIG. 4 is a cross-sectional view of the lighting device. In FIG. 4, reference numeral 105 denotes a cathode, 106 denotes an organic EL layer, and 107 denotes a glass substrate with a transparent electrode. The glass cover 102 is filled with a nitrogen gas 108 and a water catching agent 109 is provided.

  Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto. In the examples, “parts” or “%” is used, and unless otherwise specified, “vol%” is used. The numbers of the host compounds used in the organic EL device of the present invention in Tables 1 and 2 correspond to the numbers of the specific examples of the compounds represented by the general formulas (1), (7) and (8). I do. The numbers of the electron blocking compounds used in the organic EL devices of the present invention in Tables 1 and 2 correspond to the numbers of the specific examples of the compounds represented by the general formulas (3) to (6).

  << Compounds used in Examples >>

[Example 1]
<< Preparation of organic EL element >>
(1) Preparation of Organic EL Element 101 On a glass substrate having a size of 50 mm × 50 mm and a thickness of 0.7 mm, ITO (indium tin oxide) was formed into a film with a thickness of 150 nm as an anode, followed by patterning. The transparent substrate provided with the ITO transparent electrode was subjected to ultrasonic cleaning with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes, and then fixed to a substrate holder of a commercially available vacuum evaporation apparatus. .

  In each of the resistance heating boats for vapor deposition in the vacuum vapor deposition apparatus, the constituent material of each layer was filled in an amount optimal for producing each element. The resistance heating boat was made of molybdenum or tungsten.

After the pressure was reduced to a degree of vacuum of 1 × 10 ⁻⁴ Pa, the resistance heating boat containing HI-1 was energized and heated, and was deposited on the ITO transparent electrode at a deposition rate of 0.1 nm / sec. A hole injection layer was formed.

  Next, HT-1 was deposited at a deposition rate of 0.1 nm / sec to form a hole transport layer having a thickness of 30 nm.

Next, Comparative Compound 2, which is a comparative electron blocking compound, was deposited at a deposition rate of 0.1 nm / sec to form an electron blocking layer having a thickness of 15 nm.
Then, the resistance heating boat containing the comparative compound 1 and the GD-1 as the comparative host compound was heated by being energized, and was deposited on the electron blocking layer at a deposition rate of 0.1 nm / sec and 0.010 nm / sec, respectively. Evaporation was performed to form a light emitting layer having a thickness of 40 nm.

  Next, HB-1 was deposited at a deposition rate of 0.1 nm / sec to form a first electron transport layer having a thickness of 5 nm.

  Further, ET-1 was deposited thereon at a deposition rate of 0.1 nm / sec to form a second electron transport layer having a thickness of 45 nm.

  After that, lithium fluoride was evaporated to a thickness of 0.5 nm, and then 100 nm of aluminum was evaporated to form a cathode, whereby an organic EL element 101 was manufactured.

  After fabrication, the non-light-emitting surface of the organic EL element 101 is covered with a glass case in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more, and a 300 μm-thick glass substrate is used as a sealing substrate. An epoxy-based photo-curable adhesive (Lux Track LC0629B manufactured by Toagosei Co., Ltd.) is applied as a sealing material, and this is superimposed on the cathode and is brought into close contact with the transparent support substrate, and is irradiated with UV light from the glass substrate side. After curing and sealing, a lighting device having a configuration as shown in FIGS. 3 and 4 was manufactured and used as a sample.

<< Preparation of organic EL elements 102 to 112 >>
In manufacturing the organic EL device 101, the electron blocking compound and the host compound were changed to the compounds shown in Table 1. Except that, organic EL elements 102 to 112 were produced in the same manner. After the fabrication, a lighting device having a configuration as shown in FIGS. 3 and 4 was similarly fabricated and used as a sample.

<< Evaluation of organic EL elements 101-112 >>
The following evaluation was performed about each sample. Table 1 shows the evaluation results.

(1) External extraction quantum efficiency The organic EL element is energized under a constant current condition of ^2.5 mA / cm ² at room temperature (about 23 ° C.), and the light emission luminance (L0) [cd / m ² ] immediately after the start of light emission is obtained. The external extraction quantum efficiency (η) was calculated by the measurement.

  Here, the emission luminance was measured using CS-2000 (manufactured by Konica Minolta, Inc.), and the external extraction quantum efficiency was expressed as a relative value with the organic EL element 101 being 100. A higher value indicates better luminous efficiency.

(2) High-Temperature Half-Life The organic EL device was driven at a constant current at room temperature with a current that gives an initial luminance of 4000 cd / m ^2, and the time required for reducing the initial luminance to 求 め was obtained.
Next, the organic EL element was placed in a constant temperature bath under high temperature conditions (about 50 ± 5 ° C.), and the half life was calculated in the same manner as described above.
The high temperature half life of each organic EL element was calculated using the following equation.
High temperature half life (%) = (half life under high temperature conditions) / (half life at room temperature) × 100
Table 1 shows the relative values with the organic EL element 101 as 100. The larger the value, the higher the durability against a temperature change, that is, the better the light emission life under a high temperature.

(3) High Temperature Storage Stability After storing the organic EL device at 85 ° C. for 10 hours, it was stored at room temperature for 10 hours. This was repeated three cycles. Each luminance before and after storage at a constant current drive of ^2.5 mA / cm ² was measured, and each luminance ratio was determined according to the following formula, and this was used as a measure of high-temperature storage stability.
High-temperature storage stability (%) = brightness after storage ( ^2.5 mA / cm ² ) / brightness before storage ( ^2.5 mA / cm ² ) × 100
The larger the value, the smaller the change with time in the emission intensity even after storage at a high temperature, that is, the higher the storage stability at a high temperature.

  From Table 1, it was found that the organic EL elements 104 to 112 of the present invention were superior to the comparative organic EL elements 101, 102, and 103 in the quantum efficiency for external extraction, high-temperature half-life, and high-temperature storage stability.

[Example 2]
<< Preparation of organic EL element >>
(1) Preparation of Organic EL Element 201 A 120-nm thick ITO (indium tin oxide) film was formed as an anode on a 50 mm × 50 mm glass substrate having a thickness of 0.7 mm, followed by patterning. The transparent substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and washed with UV ozone for 5 minutes.

  On this transparent support substrate, a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, manufactured by Bayer, Baytron P Al 4083) to 70% with pure water was used. After forming a thin film by spin coating under the conditions of 30 seconds, the film was dried at 200 ° C. for 1 hour to provide a hole injection layer having a thickness of 20 nm.

  Next, this transparent substrate was fixed to a substrate holder of a commercially available vacuum evaporation apparatus.

  In each of the resistance heating boats for vapor deposition in the vacuum vapor deposition apparatus, the constituent material of each layer was filled in an amount optimal for producing each element. The resistance heating boat for vapor deposition was made of molybdenum or tungsten.

After reducing the pressure to a degree of vacuum of 1 × 10 ⁻⁴ Pa, the resistance heating boat containing HT-4 was energized and heated, and was deposited on the hole injection layer at a deposition rate of 0.1 nm / sec. A hole transport layer was formed.
Next, Comparative Compound 2, which is a comparative electron blocking compound, was deposited at a deposition rate of 0.1 nm / sec to form an electron blocking layer having a thickness of 10 nm.

  Next, the resistance heating boat containing the comparative compound 1 and the GD-2, which are the host compounds for comparison, was heated by being energized, and was deposited on the electron blocking layer at a deposition rate of 0.1 nm / sec and 0.010 nm / sec, respectively. Evaporation was performed to form a light emitting layer having a thickness of 40 nm.

  Next, HB-1 was deposited at a deposition rate of 0.1 nm / sec to form a first electron transport layer having a thickness of 5 nm.

  Further, ET-3 was deposited thereon at a deposition rate of 0.1 nm / sec to form a second electron transport layer having a thickness of 30 nm.

  After that, lithium fluoride was deposited to a thickness of 0.5 nm, and then 100 nm of aluminum was deposited to form a cathode, whereby an organic EL element 201 was manufactured.

  After fabrication, the non-light-emitting surface of the organic EL element 201 is covered with a glass case in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more, and a 300 μm-thick glass substrate is used as a sealing substrate. An epoxy-based photo-curable adhesive (Lux Track LC0629B manufactured by Toagosei Co., Ltd.) is applied as a sealing material, and this is superimposed on the cathode and is brought into close contact with the transparent support substrate, and is irradiated with UV light from the glass substrate side. After curing and sealing, a lighting device having a configuration as shown in FIGS. 3 and 4 was manufactured and used as a sample.

<< Preparation of organic EL elements 202 to 212 >>
In manufacturing the organic EL device 201, the electron blocking compound and the host compound were changed to the compounds shown in Table 2. Except for this, organic EL elements 202 to 212 were produced in the same manner. After the fabrication, a lighting device having the configuration shown in FIGS. 3 and 4 was similarly fabricated and used as a sample.

<< Evaluation of organic EL elements 201-212 >>
The following evaluation was performed about each sample.

  The external extraction quantum efficiency, high-temperature half-life, and high-temperature storage stability were evaluated in the same manner as in Example 1. The external extraction quantum efficiency and the high temperature half life were represented by relative values with each characteristic value of the organic EL element 201 being 100.

  Table 2 shows the evaluation results.

  From Table 2, it was found that the organic EL elements 204 to 212 of the present invention were superior to the comparative organic EL elements 201, 202, and 203 in the quantum efficiency for external extraction, high-temperature half-life, and high-temperature storage stability.

[Example 3]
<< Production of full-color display >>
(1) Production of blue light-emitting element << Production of organic EL element 301 >>
After patterning a substrate (NA45 manufactured by NH Techno Glass Co., Ltd.) on a 100 mm × 100 mm × 1.1 mm glass substrate on which ITO (indium tin oxide) was formed to a thickness of 100 nm as an anode, the ITO transparent electrode was formed. The transparent support substrate provided with was subjected to ultrasonic cleaning with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  This transparent support substrate was fixed to a substrate holder of a commercially available vacuum evaporation apparatus, while 200 mg of HT-1 was placed in a molybdenum resistance heating boat, and mCP (1,3- Bis-N carbazolylbenzene), 200 mg of HB-2 in another molybdenum resistance heating boat, 100 mg of BD-1 as a luminescent dopant in another molybdenum resistance heating boat, and another molybdenum resistance heating boat 200 mg of ET-2 was put in a resistance heating boat, and attached to a vacuum evaporation apparatus.

Next, after the pressure in the vacuum chamber was reduced to 4 × 10 ⁻⁴ Pa, the molybdenum resistance heating boat containing HT-1 was heated by being energized and vapor-deposited on the transparent support substrate at a vapor-deposition rate of 0.1 nm / sec. Then, a hole transport layer having a layer thickness of 40 nm was provided.
Further, the molybdenum resistance heating boat containing mCP (1,3-bis-Ncarbazolylbenzene) and BD-1 was heated by energizing, and the deposition rate was 0.2 nm / sec and 0.012 nm / sec, respectively. Then, a light emitting layer having a thickness of 40 nm was provided by co-evaporation on the hole transport layer. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Further, the molybdenum resistance heating boat containing HB-2 was energized and heated, and was vapor-deposited on the light-emitting layer at a vapor deposition rate of 0.1 nm / sec to provide a 10-nm-thick hole blocking layer. .

  Further, the resistance heating boat containing ET-2 was heated by being energized and vapor-deposited on the hole blocking layer at a vapor deposition rate of 0.1 nm / sec to provide an electron transport layer having a thickness of 40 nm. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Subsequently, 0.5 nm of lithium fluoride and 110 nm of aluminum were deposited to form a cathode, whereby an organic EL element 301 was manufactured.

  After fabrication, the non-light-emitting surface of the organic EL element 301 is covered with a glass case, and a 300 μm-thick glass substrate is used as a sealing substrate, and an epoxy-based photocurable adhesive (Lux made by Toagosei Co., Ltd.) is used as a sealing material around it. Track LC0629B) was applied, and this was overlaid on the cathode, brought into close contact with the transparent support substrate, irradiated with UV light from the glass substrate side, cured, and sealed, as shown in FIGS. 3 and 4. A lighting device having such a configuration was constructed and used as a sample.

(2) Production of Green Light Emitting Element The organic EL element 204 of Example 2 was used as a green light emitting element.

(3) Production of red light emitting element << Production of organic EL element 302 >>
In the organic EL element 204 of Example 2, which is a green light emitting element, the light emitting dopant was changed from GD-2 to RD-1. Except for this, the organic EL element 302 as the red light emitting element was manufactured in the same manner as the blue light emitting element 301.

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

  FIG. 2 shows only a schematic diagram of the display unit A of the display device manufactured.

  As shown in FIG. 2, the display unit A includes a plurality of pixels 3 (pixels in a red region, pixels in a green region, and pixels in a green region, which are arranged in parallel with a wiring unit including a plurality of scanning lines 5 and data lines 6 on the same substrate. Blue region pixels). The scanning lines 5 and the plurality of data lines 6 of the wiring portion are each made of a conductive material. The scanning lines 5 and the data lines 6 are orthogonal to each other in a grid pattern and are connected to the pixels 3 at orthogonal positions (details are not shown).

  The plurality of pixels 3 are driven by an active matrix method including an organic EL element corresponding to each emission color, a switching transistor as an active element, and a driving transistor, and a scanning signal is transmitted from the scanning line 5. And an image data signal from the data line 6, and emits light according to the received image data. Thus, a full-color display device was manufactured by appropriately arranging the red, green, and blue pixels 3 in parallel.

  It was confirmed that the obtained full-color display device was driven to provide a full-color moving image display having high luminance, high temperature durability, and excellent storage stability at high temperatures.

Reference Signs List 1 display 3 pixel 5 scanning line 6 data line A display unit B control unit 101 organic EL element 102 glass cover 105 cathode 106 organic EL layer 107 glass substrate with transparent electrode 108 nitrogen gas 109 water trapping agent

Claims (10)

An organic electroluminescence device in which an organic layer including a light emitting layer and an electron blocking layer is sandwiched between an anode and a cathode, wherein the light emitting layer has an aromatic heterocyclic ring having a structure represented by the following general formula (1). An organic electroluminescent device comprising a derivative, and wherein the electron blocking layer contains at least one of aromatic heterocyclic derivatives having a structure represented by the following general formulas (3) to (6). Luminescent element.

(In the general formula (1),
Y ₁ , Y ₂ and Y ₃ each independently represent CR ′ or a nitrogen atom, and at least one of Y ₁ , Y ₂ and Y ₃ is a nitrogen atom.
R ′, Ar ₁ and Ar ₂ are each independently
Hydrogen atom,
A substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or
Represents a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms.
R ′, Ar ₁ and Ar ₂ are not all hydrogen atoms at the same time.
L is
Single bond,
A substituted or unsubstituted alkylene group having 1 to 12 carbon atoms,
A substituted or unsubstituted arylene group having 6 to 30 ring carbon atoms,
It represents a substituted or unsubstituted heteroarylene group having 5 to 30 ring atoms, or a divalent linking group composed of a combination thereof.
R ₁ and R ₂ each independently represent a substituent.
n ₁ represents an integer of 0 to 4, _{n 2} is an integer of 0 to 3 and Table, _{n 1} and _{n 2} are not to become 1 at the same time.
n ₁₃ represents an integer of 0-1.
When n ₁ and n ₂ are each 2 or more, R ₁ and R ₂ may be the same or different, and when R ₁ and R ₂ are adjacent to each other, a ring may be formed.
A ₁ and A ₂ represent a compound represented by the following general formula (2). )

(In the general formula (2), Z ₁ and Z ₂ each independently represent an aromatic heterocyclic ring which may have a substituent or an aromatic hydrocarbon ring which may have a substituent; ₃ represents a divalent linking group or a simple bond.)

(In the general formulas (3) to (6),
R _{3 to} R ₇ each independently represent a substituent.
n ₃ , n ₄ , n _5, and n ₇ each independently represent an integer of 0 to 4, and n ₆ represents an integer of 0 to 2.
When n _{3 to} n ₇ are each 2 or more, R _{3 to} R ₇ may be the same or different, and when R _{3 to} R ₇ are adjacent to each other, a ring may be formed.
Ar ₃ and Ar ₄ are each independently:
A substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or
Represents a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms.
X represents an oxygen atom, a sulfur atom or _{N-R 8,.}
R ₈ is a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or
A substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or
Represents a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms. )   An organic electroluminescence device in which an organic layer including a light emitting layer and an electron blocking layer is sandwiched between an anode and a cathode, wherein the light emitting layer has an aromatic heterocyclic ring having a structure represented by the following general formula (7). An organic electroluminescent device comprising a derivative, and wherein the electron blocking layer contains at least one of aromatic heterocyclic derivatives having a structure represented by the following general formulas (3) to (6). Luminescent element.

  (In the general formula (7),
Y ₁ , Y ₂ And Y ₃ Each independently represents CR ′ or a nitrogen atom; ₁ , Y ₂ And Y ₃ At least one is a nitrogen atom.
R ', Ar ₁ And Ar ₂ Are, independently of each other,
  Hydrogen atom,
  A substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or
  Represents a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms.
  R ', Ar ₁ And Ar ₂ Are not all hydrogen atoms at the same time.
L is
  Single bond,
  A substituted or unsubstituted alkylene group having 1 to 12 carbon atoms,
  A substituted or unsubstituted arylene group having 6 to 30 ring carbon atoms,
  A substituted or unsubstituted heteroarylene group having 5 to 30 ring atoms, or
  It represents a divalent linking group consisting of these combinations.
R ₁ And R ₂ Each independently represents a substituent.
n ₁ Represents an integer of 0 to 4; ₂ Represents an integer of 0 to 3.
  Note that n ₁ And n ₂ Is 2 or more, R ₁ And R ₂ May be the same or different, and R ₁ And R ₂ May be adjacent to each other to form a ring.
A ₁ And A ₂ Represents a compound represented by the following general formula (2). )

  (In the general formula (2), Z ₁ And Z ₂ Each independently represents an aromatic heterocyclic ring which may have a substituent, or an aromatic hydrocarbon ring which may have a substituent; ₃ Represents a divalent linking group or a simple bond. )

  (In the general formulas (3) to (6),
R ₃ ~ R ₇ Each independently represents a substituent.
n ₃ , N ₄ , N ₅ And n ₇ Each independently represents an integer of 0 to 4; ₆ Represents an integer of 0 to 2.
  Note that n ₃ ~ N ₇ Is 2 or more, R ₃ ~ R ₇ May be the same or different, and R ₃ ~ R ₇ May be adjacent to each other to form a ring.
Ar ₃ And Ar ₄ Are, independently of each other,
  A substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or
  Represents a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms.
X represents an oxygen atom, a sulfur atom, or NR ₈ Represents
R ₈ Is a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or
  A substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or
  Represents a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms. ) The organic electroluminescent device according to claim 1, wherein the compound represented by the general formula (1) is represented by the following general formula (8).

Before SL Y ₁ to Y ₃ is an organic electroluminescent device according to any one of claims 1 to 3, characterized in that all represent nitrogen atom. Before SL Ar ₁ and Ar ₂ are organic electroluminescent device as claimed in any one of claims 4, characterized in that a substituted or unsubstituted ring forming aryl group having 6 to 30 carbon atoms .   The organic electroluminescence device according to claim 1, wherein the light emitting layer contains a phosphorescent dopant.   The organic electroluminescence device according to any one of claims 1 to 6, wherein the light emitting layer further contains a host compound having a structure different from that of the aromatic heterocyclic derivative.   The organic electroluminescence device according to any one of claims 1 to 7, wherein the light emitting layer and the electron blocking layer are adjacent to each other.   A display device comprising the organic electroluminescence device according to claim 1.   A lighting device comprising the organic electroluminescent element according to claim 1.

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