JP2001076879A - Organic electroluminescent element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance light emitting efficiency, and to improve durability by forming one of organic layers as an electron transport layer, and forming the constitutive material of an organic compound having a specific structure. SOLUTION: A compound expressed by formula I and formula II is used as a constitutive material of an electron transport layer. In the formula I and the formula II, M represents tetravalent metal, (n1) represents an integer of 1 to 3, (n2) represents 1 or 2, R1 to R6 respectively independently represent a hydrogen atom, a halogen atom, a halogenated alkyl group, a nitro group, a lower alkyl group, a lower alkoxy group, an aralkyl group, an alkenyl group, a carboxy group, a substituted or nonsubstituted aryl group, a substituted or nonsubstituted cycloalkyl group, a substituted or nonsubstituted heterocyclic group, a dialkyl amino group, a diaryl amino group, a diphenyl group or a naphthyl group, L represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a substituted or nonsubstituted aryl group, a substituted or nonsubstituted cycloalkyl group and a substituted or nonsubstituted heterocyclic group, and X represents a halogen atom.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device widely used as various display devices, and to an organic electroluminescent device having high efficiency and excellent stability.

[0002]

2. Description of the Related Art An electroluminescent device is capable of displaying a brighter and clearer display than a liquid crystal device due to self-luminous light.
It has been studied by many researchers since ancient times. As the electroluminescent device that has reached the practical level at present, the inorganic material Z
There is an element using nS. However, such an inorganic electroluminescent element has not been widely used since a driving voltage of 200 V or more is required for light emission.

On the other hand, an organic electroluminescent device, which is an electroluminescent device using an organic material, has been far from a practical level in the past. W. The characteristics have been drastically improved by the laminated structure element developed by Tang et al. They consist of a layer composed of a phosphor that can transport electrons with a stable structure of the deposited film (electron transporting light emitting layer) and a layer composed of an organic substance capable of transporting holes (hole transport layer). After stacking, both carriers were successfully injected into the phosphor to emit light. As a result, the luminous efficiency of the organic electroluminescent device is improved, and 1000 cd / m at a voltage of 10 V or less.
^Two or more luminescence can be obtained. Since then, many researchers have studied to improve the characteristics, and at present, luminescence characteristics of 10,000 cd / m ² or more have been obtained.

[0004] In such an organic electroluminescent device, the characteristics greatly change depending on the organic material and electrode material constituting the device. In particular, organic materials fulfill important functions such as charge transport, recombination, and light emission. To realize a device having excellent characteristics, it is important to select a material suitable for each function. Since the organic electroluminescent element is a charge injection type device, selection of a charge transport material used for an electron transport layer capable of transporting electrons is particularly important.

[0005] Charge transport materials are broadly classified into hole transport materials and electron transport materials. As the hole transporting material, a triphenylamine derivative is generally used. On the other hand, use of an oxadiazole derivative or a triazole derivative as an electron transport material has been studied. However, films using these materials are liable to cause agglomeration, and when used in devices, there is a problem in that the durability is significantly deteriorated. Also,
In addition to these derivatives, quinolinol-based metal complexes have been studied as materials for electron transport.
A typical material that has been studied so far is tris (8-hydroxyquinoline) aluminum (Alq) shown in Chemical Formula 6.

[0006]

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However, in each case, both the luminous efficiency and the driving durability have only insufficient characteristics for practical use.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to realize an organic electroluminescent device having high luminous efficiency and excellent durability by improving an organic material used for the organic electroluminescent device and its use. It is in.

[0009]

According to the present invention, there is provided an organic electroluminescent device having a pair of electrodes and at least one organic layer sandwiched between the pair of electrodes, wherein one of the organic layers has an electron transporting property. And a constituent material thereof is a compound represented by the following (Chem. 7) or (Chem. 8).

[0010]

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[0011]

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Here, M ₁ represents a tetravalent metal, and n ₁ is 1
And n ₂ is an integer of 1 or 2. R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ each independently represent a hydrogen atom, a halogen atom, a halogenated alkyl group, a nitro group, a lower alkyl group, a lower alkoxy group, an aralkyl group, an alkenyl group, A carboxyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted heterocyclic group, a dialkylamino group, a diarylamino group, a diphenyl group or a naphthyl group. L represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted cycloalkyl group or a substituted or unsubstituted heterocyclic group. X represents a halogen atom.

According to the present invention, the transport of charges, particularly electrons, in the device becomes smooth, the efficiency of the device is improved, and the driving durability is improved.

Further, the present invention provides an organic electroluminescent device having a pair of electrodes and at least one organic layer sandwiched between the pair of electrodes, wherein one of the organic layers is an electron transport layer, An organic electroluminescent device, wherein the electron transport layer is composed of two or more kinds of organometallic complexes, and the valence of a metal contained in the organometallic complex is two or more kinds.

According to the present invention, the stability of the electron transport layer as a film is improved, the storage stability is improved, and the dielectric breakdown during driving is suppressed, and the driving durability is improved.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention is directed to an organic electroluminescent device having a pair of electrodes and at least one or more organic layers sandwiched between the pair of electrodes. One of the layers is an electron transport layer, and its constituent material is a compound represented by the following (Chemical Formula 9) or (Chemical Formula 10).

[0017]

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[0018]

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Here, M ₁ represents a tetravalent metal, and n ₁ is 1
And n ₂ is an integer of 1 or 2. R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ each independently represent a hydrogen atom, a halogen atom, a halogenated alkyl group, a nitro group, a lower alkyl group, a lower alkoxy group, an aralkyl group, an alkenyl group, A carboxyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted heterocyclic group, a dialkylamino group, a diarylamino group, a diphenyl group or a naphthyl group. L represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted cycloalkyl group or a substituted or unsubstituted heterocyclic group. X represents a halogen atom.

With this configuration, since a tetravalent metal is used as the central metal, the electron transporting ability of the molecule is improved. as a result,
The efficiency of the device was improved, and the driving durability was improved.

According to a second aspect of the present invention, a pair of electrodes are provided.
In an organic electroluminescent device having at least one organic layer sandwiched between the pair of electrodes, one of the organic layers is an electron transport layer, and the electron transport layer is formed of two or more kinds of organometallic complexes. Wherein the valence of the metal contained in the organometallic complex is two or more.

According to this configuration, since two or more kinds of materials are mixed and used, the stability of the film of the electron transport layer is increased, the storage durability is improved, and the dielectric breakdown during driving is suppressed, and the driving durability is reduced. Improved.

According to a third aspect of the present invention, at least one of the two or more kinds of organometallic complexes contained in the electron transport layer is represented by the following formula (11), (12) or (13). The organic electroluminescent device according to claim 2, which is a compound.

[0024]

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[0025]

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Here, M ₁ represents a tetravalent metal, and n ₁ is 1
And n ₂ is an integer of 1 or 2. R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ each independently represent a hydrogen atom, a halogen atom, a halogenated alkyl group, a nitro group, a lower alkyl group, a lower alkoxy group, an aralkyl group, an alkenyl group, A carboxyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted heterocyclic group, a dialkylamino group, a diarylamino group, a diphenyl group or a naphthyl group. L represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted cycloalkyl group or a substituted or unsubstituted heterocyclic group. X represents a halogen atom.

[0027]

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Here, M ₂ represents a tetravalent metal. R ₁ , R
₂ , R ₃ , R ₄ and R ₅ each independently represent a hydrogen atom, a chlorine atom, a bromine atom, a lower alkyl group, a lower alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted cycloalkyl group, Or an unsubstituted heterocyclic group dialkylamino group, diarylamino group, diphenyl group or naphthyl group.

According to this configuration, since a material having an excellent electron transporting ability is used in combination, the stability of the film of the electron transporting layer and the electron transporting ability are improved, and the durability of the device is greatly improved.

Further, by securing a certain thickness or more as the electron transporting layer, the driving voltage could be reduced.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a sectional view showing a schematic structure of an organic electroluminescent device according to the present invention. An anode 2 is formed on a glass substrate 1, and a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode 6 are formed thereon.

In such a configuration, a material capable of injecting holes into the organic layer is used for the anode 2. Specific examples include indium tin oxide (ITO), gold, and a conductive polymer material.

The material for forming the hole transport layer 3 is required to have a high hole mobility, to be able to form a thin film without pinholes, and to be transparent to the fluorescence of the light emitting layer 4. You. Representative materials satisfying these requirements include, but are not limited to, tetraphenylbenzidine derivatives and the like.

The hole transporting layer 3 is usually formed by a vapor deposition method using resistance heating. However, the hole transporting layer 3 may be formed by dispersing the above materials in a polymer such as polycarbonate by spin coating or casting. Alternatively, in the case of a polymer having a hole transporting property, such as polyvinyl carbazole or polyparaphenylene vinylene, a film may be formed by spin coating or the like alone.

The light emitting layer 4 is required to have fluorescence and to be capable of generating excitons by recombination of electrons and holes. Usually, it is prepared by a vapor deposition method using resistance heating. However, a material obtained by dispersing the above-mentioned materials in a polymer such as polycarbonate may be formed into a film by a spin coating method or a casting method.

Further, a film in which a small amount of a fluorescent dye is dispersed in a material having excellent film forming properties may be used as the light emitting layer.
This method is very effective for fluorescent dyes that are liable to crystallize or cause concentration quenching by themselves.

Although not particularly shown, the light emitting layer 4 can also serve as the hole transport layer 3 or the electron transport layer 5.
In the former case, the layer composed of an organic substance has a two-layer structure of a light emitting layer / an electron transport layer. In the latter case, the layer composed of an organic substance has a two-layer structure of a hole transport layer / a light emitting layer.

The cathode 6 needs to be able to inject electrons into the organic layer and to have excellent environmental stability. Examples of the metal satisfying these requirements include aluminum, magnesium, an alloy of aluminum and lithium, an alloy of magnesium and silver, and an alloy of silver and lithium. Alternatively, a similar effect can be obtained by laminating a thin film of lithium fluoride or a metal oxide (5 nm or less) and a metal (such as aluminum).

The cathode 6 was formed by a resistance heating method. When an alloy is used, it is formed by a co-evaporation method in which two kinds of metals are simultaneously sputtered from independent evaporation sources by a resistance heating method to form a film. The composition ratio of the alloy is determined by adjusting the respective deposition rates.

Further, for the cathode 6, an alloy prepared in advance with a predetermined component ratio may be used. In addition to the resistance heating method, it can be formed by an electron beam evaporation method or a sputtering method.

Hereinafter, more detailed embodiments of the present invention will be representatively described. It goes without saying that the present invention is not limited by these.

(Embodiment 1) An indium tin oxide film (ITO) was previously formed as a transparent anode on glass and patterned in the form of an electrode. After sufficiently washing the substrate, the substrate was set in a vacuum device together with the material to be deposited, and the substrate was evacuated to 10 ^-4 Pa. afterwards,
N, N'-bis [4 '-(N, N-diphenylamino) -4-biphenylyl] -N, N'-diphenylbenzidine (T
PT) was formed into a 50 nm film. Then, as a light emitting layer, Al
q was formed into a 25 nm film. Further, a 25 nm thick quinolinol metal complex (1) shown in Chemical Formula 14 was formed as an electron transporting layer, and an AlLi alloy was formed as a cathode to a thickness of 150 nm to form a device. These films were continuously formed without breaking the vacuum. The film thickness was monitored with a quartz oscillator.

Immediately after the device was manufactured, the electrodes were taken out in dry nitrogen, and the characteristics were measured. When a voltage was applied to the obtained device, uniform yellow-green light emission was obtained. The drive voltage and the emission luminance when a current of 100 mA / cm ² was applied were measured.
At 6 V, the light emission luminance was 2,920 cd / m ² . The device was dried in dry nitrogen at an initial luminance of 1000 cd / m ^2.
, Continuous driving (constant current), the brightness is half of 500
Time required to decrease to cd / m ² (luminance half-life)
Was 690 h. Further, the voltage increase after driving for 500 hours was 0.8 V.

[0045]

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(Embodiment 2) An organic electroluminescent device was manufactured in the same manner as in the first embodiment except that the material used for the light emitting layer was changed to DPVBi shown in (Chemical Formula 15).
When a voltage was applied to the obtained device, uniform blue light emission was obtained. When the driving voltage and the emission luminance when a current of 100 mA / cm ² was applied were measured, the driving voltage was 6.1 V and the emission luminance was 2470 cd / m ² . The device was dried at an initial luminance of 1000 in dry nitrogen.
Upon continuous driving (constant current) at cd / m ² , the luminance half-life was 80 h. Further, the voltage increase after driving for 500 hours was 1.0 V.

[0047]

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(Embodiment 3) An organic electroluminescent device is manufactured in the same manner as in the first embodiment except that the material used for the electron transport layer is changed to the quinolinol metal complex (2) shown in (Formula 16). did. When a voltage was applied to the obtained device, uniform yellow-green light emission was obtained. 100mA / cm
When the drive voltage and the light emission luminance when the current of ² was applied were measured, the drive voltage was 5.5 V and the light emission luminance was 289.
It was 0 cd / m ² . The device was continuously driven in dry nitrogen at an initial luminance of 1000 cd / m ² (constant current).
As a result, the luminance half life was 730 h. Also, 5
The voltage rise after the driving for 00h was 0.9 V.

[0049]

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(Embodiment 4) An organic electroluminescent device is manufactured in the same manner as in the first embodiment except that the material used for the electron transport layer is changed to the quinolinol metal complex (3) shown in (Formula 17). did. When a voltage was applied to the obtained device, uniform yellow-green light emission was obtained. 100mA / cm
When the drive voltage and the light emission luminance when the current of ² was applied were measured, the drive voltage was 5.3 V and the light emission luminance was 313.
It was 0 cd / m ² . The device was continuously driven in dry nitrogen at an initial luminance of 1000 cd / m ² (constant current).
As a result, the luminance half life was 810 h. Also, 5
The voltage increase after the driving for 00h was 0.4 V.

[0051]

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(Embodiment 5) The material used for the light emitting layer is D
An organic electroluminescent device was produced in the same manner as in the first embodiment, except that the material used for PVBi and the electron transport layer was changed to the quinolinol metal complex (4) shown in (Chem. 18).
When a voltage was applied to the obtained device, uniform blue light emission was obtained. When the drive voltage and the light emission luminance when a current of 100 mA / cm ² was applied were measured, the drive voltage was 6.2 V and the light emission luminance was 2280 cd / m ² . The device was dried at an initial luminance of 1000 in dry nitrogen.
When the device was continuously driven (constant current) at cd / m ² , the luminance half-life was 50 hours. Further, the amount of voltage rise after driving for 500 hours was 1.1 V.

[0053]

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(Embodiment 6) As in the first embodiment, after sufficiently cleaning the substrate, the substrate is set together with the material to be deposited in a vacuum apparatus, and the chamber is evacuated to 10 ^-4 Pa. Then, 50 nm of TPT was formed as a hole transport layer. Then, Alq was formed into a 25 nm film as a light emitting layer. Subsequently, the quinolinol metal complex (5) shown in Chemical Formula 19 and Alq
Was formed to a thickness of 25 nm to form an electron transport layer. The mixed film was prepared by a co-evaporation method, and the mixing ratio was 1: 1 in terms of the number of molecules. Subsequently, an AlLi alloy was formed as a cathode to a thickness of 150 nm to form a device.

When a voltage was applied to the obtained device, uniform yellow-green light emission was obtained. When the driving voltage and the emission luminance when a current of 100 mA / cm ² was applied were measured, the driving voltage was 5.7 V and the emission luminance was 3000 cd.
/ M ² . When the device was continuously driven (constant current) at an initial luminance of 1000 cd / m ² in dry nitrogen, the luminance half-life was 860 h. Further, the voltage increase after driving for 500 hours was 0.6 V.

[0056]

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(Embodiment 7) Except that the combination of materials used for the electron transport layer is changed to a zinc quinolinol complex (Znq) shown in (Chemical Formula 20) and a quinolinol metal complex (5) shown in (Chemical Formula 19). An organic electroluminescent device was manufactured in the same manner as in the sixth embodiment. When a voltage was applied to the obtained device, uniform yellow-green light emission was obtained. 10
When the driving voltage and the emission luminance at the time of applying 0 mA / cm ² were measured, the driving voltage was 5.7 V and the emission luminance was 3000 cd / m ^2.
Met. The device was dried in dry nitrogen at an initial luminance of 1
The luminance half-life when continuously driven at 000 cd / m ² (constant current) was 860 h. Further, the voltage rise after driving for 500 hours was 0.6 V.

[0058]

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(Embodiment 8) An organic electric field is formed in the same manner as in the sixth embodiment except that the combination of materials used for the electron transporting layer is changed to quinolinol metal complex (1) shown in Chemical formula 14 and Alq. A light-emitting element was manufactured. When a voltage was applied to the obtained device, uniform yellow-green light emission was obtained. When the driving voltage and emission luminance at the time of applying 100 mA / cm ² were measured, the driving voltage was 5.7 V and the emission luminance was 2550.
cd / m ² . When this device was continuously driven (constant current) at an initial luminance of 1000 cd / m ² in dry nitrogen, the luminance half-life was 610 h. Further, the voltage rise after driving for 500 hours was 1.0 V.

(Embodiment 9) An organic electric field is formed in the same manner as in the sixth embodiment except that the combination of materials used for the electron transport layer is changed to quinolinol metal complex (2) shown in (Formula 16) and Alq. A light-emitting element was manufactured. When a voltage was applied to the obtained device, uniform yellow-green light emission was obtained. When the driving voltage and the emission luminance at the time of applying 100 mA / cm ² were measured, the driving voltage was 5.5 V and the emission luminance was 3210.
cd / m ² . When this device was continuously driven (constant current) at an initial luminance of 1000 cd / m ² in dry nitrogen, the luminance half-life was 890 h. Further, the voltage increase after driving for 500 hours was 0.5V.

Embodiment 10 Materials Used for Electron Transport Layer
Except that the combination of charges was changed to Znq and Alq
An organic electroluminescent device was manufactured in the same manner as in the sixth embodiment.
Was. When a voltage was applied to the obtained device, a uniform yellow-green
Color light emission was obtained. 100mA / cm^TwoDriving during application
When the voltage and emission luminance were measured, the driving voltage was 6.0 V,
Luminance luminance 2340 cd / m^TwoMet. Dry this element
Initial luminance 1000 cd / m in nitrogen^Two With continuous drive
The luminance half-life at the time of (constant current) was 420 hours.
In addition, the voltage rise after driving for 500 hours is 1.5 V.
Was.

Comparative Example 1 As Comparative Example 1, an element was produced in the same manner as in the first embodiment, except that Alq was formed to a thickness of 50 nm as both a light emitting layer and an electron transporting layer. When a voltage was applied to the obtained device, uniform yellow-green light emission was obtained. When the drive voltage and the light emission luminance when a current of 100 mA / cm ² was applied were measured, the drive voltage was 6.2 V and the light emission luminance was 2310 cd / m ² . This element was subjected to an initial luminance of 1000 cd / m ² in dry nitrogen.
, The half-life of brightness is 300
h. In addition, the amount of voltage rise after 500 hours of driving is 2.
It was 0V.

Comparative Example 2 As Comparative Example 2, DPVBi was 25 nm as a light emitting layer, and Alq was 2 as an electron transport layer.
An element was manufactured in the same manner as in the first embodiment except that a film was formed to a thickness of 5 nm. When a voltage was applied to the obtained device, uniform blue light emission was obtained. 100 mA / cm ²
When the driving voltage and the light emission luminance when the current was applied were measured, the drive voltage was 7.0 V and the light emission luminance was 202.
It was 0 cd / m ² . When this device was continuously driven (constant current) at an initial luminance of 1000 cd / m ² in dry nitrogen, the luminance half-life was 10 h. Also, 500h
The voltage rise after driving was 2.8V.

Comparative Example 3 As Comparative Example 3, 25 nm of Alq was used as the light emitting layer, and 25 n of the oxadiazole derivative (tBu-PBD) shown in Chemical Formula 21 was used as the electron transporting layer.
An element was manufactured in the same manner as in the first embodiment except that m was formed. When voltage was applied to the obtained device,
Uniform yellow-green emission was obtained. When the driving voltage and the emission luminance when a current of 100 mA / cm ² was applied were measured, the driving voltage was 7.7 V and the emission luminance was 2180.
cd / m ² . The device was continuously driven (constant current) at an initial luminance of 1000 cd / m ² in dry nitrogen. As a result, before the luminance was reduced by half, the device was broken down and did not function as a device.

[0065]

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From the results shown above, it was clarified that the device obtained in the present embodiment was superior to the device obtained in the comparative example in luminous efficiency and driving durability.

[0067]

As described above, according to the present invention, there is obtained an advantageous effect that an organic electroluminescent device having high luminous efficiency and excellent driving durability can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating a configuration of an electroluminescent device according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass substrate 2 Anode 3 Hole transport layer 4 Light emitting layer 5 Electron transport layer 6 Cathode

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Yoshikazu Hori 3-10-1, Higashi-Mita, Tama-ku, Kawasaki City, Kanagawa Prefecture Inside Matsushita Giken Co., Ltd. (72) Yuji Kudo Inventor 3-chome, Higashi-Mita, Tama-ku, Kawasaki City, Kanagawa Prefecture No.10 No.1 Matsushita Giken Co., Ltd. F term (reference) 3K007 AB00 AB03 CA01 CB01 DA00 DB03 EB00 FA01

Claims (3)

[Claims] 1. An organic electroluminescent device having a pair of electrodes and at least one or more organic layers sandwiched between the pair of electrodes, wherein one of the organic layers is an electron transport layer, and the constituent material is An organic electroluminescent device comprising a compound represented by the following (Chemical Formula 1) or (Chemical Formula 2). Embedded image Embedded image Here, M ₁ represents a tetravalent metal, n ₁ is an integer of 1 to 3, and n ₂ is an integer of 1 or 2.
R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ each independently represent a hydrogen atom, a halogen atom, a halogenated alkyl group, a nitro group, a lower alkyl group, a lower alkoxy group, an aralkyl group, an alkenyl group, Carboxyl group, substituted or unsubstituted aryl group, substituted or unsubstituted cycloalkyl group,
Represents a substituted or unsubstituted heterocyclic group, dialkylamino group, diarylamino group, diphenyl group or naphthyl group. L represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted cycloalkyl group or a substituted or unsubstituted heterocyclic group. X represents a halogen atom. 2. An organic electroluminescent device having a pair of electrodes and at least one organic layer sandwiched between the pair of electrodes, wherein one of the organic layers is an electron transport layer, Contains two or more kinds of organometallic complexes, and the metal contained in the organometallic complex has two or more valences. 3. The method according to claim 1, wherein at least one of the two or more organometallic complexes contained in the electron transport layer contains a compound represented by the following formula (3), (4) or (5). The organic electroluminescent device according to claim 2, wherein Embedded image Embedded image Here, M ₁ represents a tetravalent metal, n ₁ is an integer of 1 to 3, and n ₂ is an integer of 1 or 2.
R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ each independently represent a hydrogen atom, a halogen atom, a halogenated alkyl group, a nitro group, a lower alkyl group, a lower alkoxy group, an aralkyl group, an alkenyl group, Carboxyl group, substituted or unsubstituted aryl group, substituted or unsubstituted cycloalkyl group,
Represents a substituted or unsubstituted heterocyclic group, dialkylamino group, diarylamino group, diphenyl group or naphthyl group. L represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted cycloalkyl group or a substituted or unsubstituted heterocyclic group. X represents a halogen atom. Embedded image Here, M ₂ represents a tetravalent metal. R ₁ , R ₂ , R ₃ ,
R ₄ and R ₅ each independently represent a hydrogen atom, a chlorine atom, a bromine atom, a lower alkyl group, a lower alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted heterocyclic group. A ring group represents a dialkylamino group, a diarylamino group, a diphenyl group or a naphthyl group.