KR100669775B1 - Organic electroluminescent element - Google Patents

Abstract

The present invention provides an organic electroluminescent device having a plurality of light emitting layers between a first electrode and a second electrode, wherein an outermost layer adjacent to an electrode of the light emitting layer includes a phosphorescent dopant and a hole transport material as a host, At least one light emitting layer formed therebetween provides a phosphorescent dopant and an electron transport material as a host. The organic electroluminescent device of the present invention is improved in efficiency and lifespan by using a plurality of odd number of light emitting layers.

Organic electroluminescent element, emitting layer, host, phosphorescent dopant

Description

Organic electroluminescence display

1 is a cross-sectional view of an organic electroluminescent device according to an embodiment of the present invention.

2 is a view showing a light emitting layer of an organic electroluminescent device according to an embodiment of the present invention.

3 is a view showing an embodiment and a comparative example according to the present invention for the efficiency characteristics of the organic electroluminescent device.

4 is a view showing an embodiment and a comparative example according to the present invention for the life characteristics of the organic EL device.

The present invention relates to an organic electroluminescent device, and more particularly, to an organic electroluminescent device having improved efficiency and lifetime characteristics by employing a plurality of light emitting layers.

The light emitting material of the organic electroluminescent device is classified into a fluorescent material using excitons in a singlet state and a phosphorescent material using a triplet state according to its light emitting mechanism.

Phosphorescent materials generally have a structure of organometallic compounds containing heavy atoms, and when such phosphorescent materials are used, excitons in the triplet state, which were originally forbidden transitions, emit light through an allowable transition. The phosphorescent material can use triplet excitons with a 75% generation probability and can have a much higher luminous efficiency than fluorescent materials using singlet excitons with a 25% generation probability.

The light emitting layer using the phosphorescent material is composed of a host material and a dopant material that emits light by transferring energy therefrom. As the dopant material, various materials using iridium metal compounds have been reported at Princeton University and the University of Southern California. In particular, as the blue light emitting material, Ir compounds based on (4,6-F ₂ ppy) ₂ Irpic or fluorinated ppy ligand structures have been developed, and the host material of these materials is CBP (4,4'-). N, N'-dicarbazole-biphenyl) materials are widely used. The CBP molecule has sufficient energy transfer in the triplet state of the energy gap of green and red materials, but it is less than the energy gap of blue materials, resulting in a very inefficient endothermic transition rather than exothermic energy transfer. Is being reported. As a result, the CBP host is pointed out as a cause of problems of low blue light emission efficiency and short lifespan due to insufficient energy transfer to the blue dopant.

Recently, a method of using a carbazole compound having a triplet energy band gap larger than CBP as a host when forming an emission layer using a phosphorescent material is known.

However, when the carbazole compound known to date is used, there is much room for improvement because the efficiency and lifespan characteristics of the phosphorescent device do not reach a satisfactory level.

Accordingly, the technical problem to be achieved by the present invention is to provide an organic EL device having improved efficiency and lifetime characteristics by solving the above problems.

In order to achieve the above technical problem, in the present invention

In an organic electroluminescent device having a plurality of light emitting layers between a first electrode and a second electrode,

The outermost layer adjacent to the electrode of the light emitting layer includes a phosphorescent dopant and a hole transporting material as a host, and at least one light emitting layer between the outermost layer includes the phosphorescent dopant and an electron transporting material as a host. An organic electroluminescent device is provided.

Hereinafter, the present invention will be described in more detail.

As shown in FIG. 1, in the organic electroluminescent device, a hole injection electrode (anode) including a transparent electrode film is formed on a substrate. On the hole injection electrode, a hole injection layer (HIL), a hole transport layer (HTL), and an emission layer (EML) containing an organic material are formed in this order. In addition, a hole blocking layer HBL, an electron transport layer ETL, and an electron injection layer EIL containing an organic material are sequentially formed on the light emitting layer, and an electron injection electrode (cathode) is formed on the electron injection layer.

The organic electroluminescent device in which the light emitting layer formed between the first electrode and the second electrode has a multilayer structure, wherein the outermost layers of the light emitting layers include a phosphorescent dopant and a hole transport material as a host, and the outermost layer Provided is an organic electroluminescent device characterized in that at least one light emitting layer formed therebetween comprises an phosphorescent dopant and an electron transport material as a host.

The organic electroluminescent device having a multi-layer structure plays a role of matching the concentration of holes and electrons injected from the anode and the cathode in the light emitting layer, thereby increasing the luminous efficiency of the dopant and extending the life of the device.

According to an embodiment of the present invention, the light emitting layer includes a (2n-1) light emitting layer including a phosphorescent dopant and a hole transport material as a host, a second n light emitting layer including a phosphorescent dopant and an electron transport material as a host, and a phosphorescent dopant and a host. And a second (2n + 1) light emitting layer including a hole transport material, wherein n is a natural number of 1 to 24. When n exceeds 24, it is impossible to implement the light emitting layer in the manufacturing process. When n is 2 or more, the first light emitting layer includes the (2n-2) th light emitting layer. For example, when n is 2, the first light emitting layer, the second light emitting layer, the third light emitting layer, the fourth light emitting layer, and the fifth light emitting layer are formed. When n is 3, the first light emitting layer, the second light emitting layer, and the third light emitting layer. And a fourth light emitting layer, a fifth light emitting layer, a sixth light emitting layer, and a seventh light emitting layer. When the light emitting layer is formed in the device, a light emitting layer made of a hole transporting material and a phosphorescent dopant, and a light emitting layer made of an electron transporting material and a phosphorescent dopant may be alternately stacked.

According to one embodiment of the present invention, in the case of a light emitting layer having three plural layers, a first light emitting layer including a phosphorescent dopant and a hole transporting material as a host, a second light emitting layer including a phosphorescent dopant and an electron transporting material as a host, And a third light emitting layer including a phosphorescent dopant and a hole transport material as a host.

1 shows a light emitting layer composed of three plural layers. The thickness of the light emitting layer may be represented by a, and the first light emitting layer, the second light emitting layer, and the third light emitting layer may be sequentially stacked from the surface adjacent to the hole transport layer.

According to another embodiment of the present invention, in the case of a light emitting layer having a multi-layer structure such as 5, 7, 9, or 11, the odd numbered light emitting layer from the first electrode or the second electrode is hole transported as a phosphorescent dopant and a host. And the even-numbered light emitting layer from the first electrode or the second electrode includes a phosphorescent dopant and an electron transport material as a host.

2 shows a light emitting layer composed of five multi-layered structures. The thickness of the light emitting layer is a, and the outermost layer 21 adjacent to the hole transporting layer and the outermost layer 25 adjacent to the electron transporting layer include a phosphorescent dopant and a hole transporting material as a host, and the outermost layers 21 and 25 At least one of the layers 22, 23, 24 formed therebetween may include the phosphorescent dopant and the electron transport material as a host.

In addition, the organic electroluminescent device may be composed of a mixture of the above materials or to introduce additional layers to improve the efficiency and life of the device. In addition, the number of layers used may be reduced by using a material having various functions simultaneously to simplify the fabrication of the device.

According to one embodiment of the present invention, the hole transporting material constituting the light emitting layer may be an aryl amine-based compound as the material having hole transporting properties, preferably a carbazole-based compound.

The hole transporting material having the hole transporting property uses a carbazole compound, and examples of the carbazole compound include 1,3,5-tricarbazolylbenzene and 4,4'-biscarbazolyl. Biphenyl {4,4'-biscarbazolylbiphenyl} [CBP], polyvinylcarbazole, m-biscarbazolylphenyl, 4,4'-biscarbazolyl-2,2'-dimethylbi Phenyl {(4,4'-biscarbazolyl-2,2'-dimethylbiphenyl)} [dmCBP], 4,4 ', 4 "-tri (N-carbazolyl) triphenylamine {4,4', 4" -tri (N-carbazolyl) triphenylamine}, 1,3,5-tri (2-carbazolylphenyl) benzene {1,3,5-tris (2-carbazolylphenyl) benzene}, 1,3,5-tris (2-carba Group consisting of zolyl-5-methoxyphenyl) benzene {1,3,5-tris (2-carbazolyl-5-methoxyphenyl) benzene} and bis (4-carbazolylphenyl) silane {bi (4-carbazolylphenyl) silane} It is preferably at least one selected from.

The material having an electron transporting property may be at least one compound selected from an organometallic complex including a metal and an organic ligand, a spirofluorene compound, an oxadiazole compound, a phenanthroline compound, a triazine compound, and a triazole compound. Can be.

Non-limiting examples of the organometallic complex include bis (8-hydroxyquinolato) biphenoxy metal and bis (8-hydroxyquinolato) phenoxy metal. (8-hydroxyquinolato) phenoxy metal}, bis (2-methyl-8-hydroxyquinolato) biphenoxy metal {bis (2-methyl-8-hydroxyquinolato) biphenoxy metal}, bis (2-methyl-8- Hydroxyquinolato) phenoxy metal) {bis (2-methyl-8-hydroxyquinolato) phenoxy metal}, bis (2-methyl-8-quinolinolato) (para-phenyl-phenololato) metal {Bis (2-methyl-8-quinolinolato) (para-phenyl-phenolato) metal}, and bis (2- (2-hydroxyphenyl) quinolato) metal {bis (2- (2-hydroxyphenyl) quinolato) metal} At least one selected from the group consisting of, the metal is aluminum (Al), zinc (Zn), beryllium (Be), or gallium (Ga).

The electron transporting materials are particularly preferably bis (8-hydroxyquinolato) biphenoxy aluminum, bis (8-hydroxyquinolato) phenoxy aluminum, bis (2-methyl-8-hydroxyquinolato) Phenoxy aluminum, bis (2-methyl-8-hydroxyquinolato) phenoxy aluminum, bis (2-methyl-8-quinolinolato) (para-phenyl-phenololato) aluminum (BAlq), or bis Preference is given to (2- (2-hydroxyphenyl) quinolato) zinc.

The spirofluorene-based compound is a structure having a linking ring between two spirofluorenes, the linkage is triazole, oxadiazole, naphthalene, anthracene Or phenyl, or the like, and the position 9 of each fluorene is substituted with O, S, Se, NR, PR, or the like, or NR or PR is substituted between two spirofluorenes. It can be a structure that directly connects. Each R is H, or a C 6 to C 20 alkyl group, a C 5 to 20 aryl group having 1 to 20 carbon atoms, a C 2 to 20 heteroaryl group, and a C 1 to 20 alkoxy group having 6 carbon atoms It is a substituent selected from the group which consists of an aryl group of 20. Preferably, the spirofluorene-based compound is 2,5-disspirobifluorene-1,3,4-oxadiazole (2,5-Dispirobifluorene-1,3,4-oxadiazole).

Examples of the oxadiazole-based compound include (4-biphenylyl) -5- (4-tertbutylphenyl) -1,3,4-oxadiazole and the like, and examples of the phenanthroline-based compound include 2,9-dimethyl-4,7-diphenyl-9,10-phenanthroline (BCP), and the like. Examples of the triazine-based compound include 2,4,6-tris (diphenylamino) -1. , 3,5-triazine, 2,4,6-tricarbazolo-1,3,5-triazine, 2,4,6-tris (N-phenyl-2-naphthylamino) -1,3, 5-triazine or 2,4,6-tris (N-phenyl-1-naphthylamino) -1,3,5-triazine, etc. are mentioned. Examples of the triazole-based compound include 3-phenyl-4- (1'-naphthyl) -5-phenyl-1,2,4-triazole.

In addition, at least one selected from a carbazole compound having a hole transporting property, an oxadiazole compound having an electron transporting property, a phenanthroline-based compound, a triazine-based compound, and a triazole-based compound is used as a host when forming an emission layer including a phosphorescent dopant. In this case, since the hole blocking layer HBL is not formed, the device structure may be simplified and the luminous efficiency and lifespan characteristics may be improved.

The phosphorescent dopant used in forming the light emitting layer of the present invention is a light emitting material, and non-limiting examples thereof include bisthienylpyridine acetylacetonate iridium, bis (benzothienylpyridine) acetylacetonate iridium {bis benzothienylpyridine) acetylacetonate Iridium}, bis (2-phenylbenzothiazole) acetylacetonate iridium {Bis (2-phenylbenzothiazole) acetylacetonate Iridium}, bis (1-phenylisoquinoline) iridium acetylacetonate {bis (1-phenylisoquinoline) Iridium acetylacetonate}, tris (1-phenylisoquinoline) Iridium}, or tris (2-phenylpyridine) Iridium} (Ir (ppy) ₃ ) Can be.

According to one embodiment of the present invention, in the light emitting layer composed of three or more layers, the first light emitting layer and the third light emitting layer are carbazole-based compounds, preferably 4,4'-biscarbazolyl biphenyl (CBP) as a host. And an iridium complex, preferably tris (2-phenylpyridine) iridium (Ir (ppy) ₃ ), as a phosphorescent dopant. The second light emitting layer further comprises an organometallic complex, preferably bis (2-methyl-8-quinolinolato) (para-phenyl-phenololato) aluminum (BAlq) as a host, and an iridium complex as a phosphorescent dopant, preferably Preferably tris (2-phenylpyridine) iridium (Ir (ppy) ₃ ).

The content of the material used as the host in each light emitting layer may be 70 to 99 parts by weight based on 100 parts by weight of the total weight of each light emitting layer forming material. If it is less than 70 parts by weight, the quenching phenomenon of the triplet occurs, and the efficiency is lowered. If it is more than 99 parts by weight, the light emitting material is insufficient and the efficiency and lifetime are lowered, which is not preferable.

The content of the hole transporting material used as the host of the outermost layer in the plurality of light emitting layers may be 70 to 99 parts by weight based on 100 parts by weight of the total weight of the outermost light emitting layer forming material. If it is less than 70 parts by weight does not improve the characteristics compared to the single-layer host, if it exceeds 99 parts by weight is not preferable because the effect does not appear to improve the properties.

The content of the electron transporting material in the light emitting layer formed between the outermost layers may be 70 to 99 parts by weight based on 100 parts by weight of the light emitting layer forming material. If it is less than 70 parts by weight, light emission is interrupted by quenching. If it is more than 99 parts by weight, the light emitting dopant does not emit light of an appropriate intensity.

According to one embodiment of the present invention, the total thickness of the light emitting layers constituting the plurality of light emitting layers may be 100 to 800 kPa. If it is less than 100 mW, efficiency and lifetime will fall, and if it exceeds 800 mW, a driving voltage will rise and it is unpreferable. In the light emitting layer consisting of three plural layers, the first light emitting layer and the third light emitting layer may have a thickness of 50 to 400 kPa, and the second light emitting layer may have a thickness of 50 to 400 kPa. If it is out of the thickness range, it is not preferable because the concentration of the appropriate carrier in the light emitting layer cannot be maintained.

Each light emitting layer is formed of a thin film as described above, and the thin film is formed by thermal evaporation in a high vacuum or by spin coating after melting in a solution depending on the type of material used. coating, dip-coating, doctor-blading, inkjet printing, or thermal transfer may be employed, and thermal evaporation may be used. Preference is given to using.

In the organic electroluminescent device of the present invention, at least one selected from a hole injection layer and a hole transport layer may be stacked between the first electrode or the second electrode and the outermost layer of the light emitting layers. In addition, one or more selected from an electron blocking layer, an electron transport layer, and an electron injection layer may be stacked between the first electrode or the second electrode and the outermost layer of the light emitting layers. In addition to the light emitting layer, other organic layers may be formed in various ways as described in the light emitting layer forming method.

Hereinafter, the manufacturing method of the organic EL device of the present invention will be described.

Referring to Figure 1 describes a method for manufacturing an organic EL device according to an embodiment of the present invention.

First, an anode is formed on a substrate by coating an anode material, which is a first electrode. Herein, a substrate used in a conventional organic electroluminescent device is used, but a glass or organic substrate or a transparent plastic substrate having excellent transparency, surface smoothness, ease of handling, and waterproofness is preferable. The anode material may be a high work function metal (≥4.5 eV), or a transparent and highly conductive indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO ₂ ), and zinc oxide. (ZnO) or the like is used.

A hole injection layer (HIL) is selectively formed on the anode by coating the hole injection layer material in various ways such as the above-described vacuum thermal deposition or spin coating. It is preferable that the thickness of a hole injection layer is 50-1500 kPa here. If the thickness of the hole injection layer is less than 50 kV, the hole injection characteristic is lowered, and if the thickness of the hole injection layer is more than 1500 kV, it is not preferable because of the increase of the driving voltage.

The hole injection layer material is not particularly limited, and copper phthalocyanine (CuPc) or Starburst type amines such as TCTA, m-MTDATA, IDE406 (Idemitsu Corp. material), and the like may be used as the hole injection layer.

A hole transport layer (HTL) is selectively formed by coating the hole transport layer material on the hole injection layer formed by the above process by various methods such as the above-described vacuum thermal deposition or spin coating. The hole transport material is not particularly limited, and N, N'-bis (3-methylphenyl) -N, N'-diphenyl- [1,1-biphenyl] -4,4'-diamine (TPD), N, N'-di (naphthalen-1-yl) -N, N'-diphenyl benzidine, N, N'-di (naphthalen-1-yl) -N, N'-diphenyl-benxidine: α-NPD) , IDE320 (Idemitsu Co., Ltd.), etc. are used. It is preferable that the thickness of a positive hole transport layer is 50-1500 kPa here. If the thickness of the hole transport layer is less than 50 kV, the hole transport property is deteriorated.

Subsequently, the light emitting layer EML is formed on the hole transport layer by using a mixture of the above-described electron transport material and hole transport material as a host and a phosphorescent dopant together. The light emitting layer forming method is not particularly limited, but various methods such as vacuum deposition, inkjet printing, laser transfer, photolithography, etc. are used as exemplified above.

It is preferable that the thickness of the said light emitting layer is 100-800 GPa. If the thickness of the light emitting layer is less than 100 kW, the efficiency and lifetime are lowered. If the thickness of the light emitting layer is more than 800 kW, the driving voltage increases, which is not preferable.

A hole blocking material (HBL) is selectively formed on the light emitting layer by coating a material for hole blocking by various methods such as the above-described vacuum deposition or spin coating. The material for the hole blocking layer used at this time is not particularly limited, but should have an ionization potential higher than that of the light emitting compound while having an electron transport ability, and typically Balq, BCP, TPBI, and the like are used. If the thickness of the hole blocking layer is preferably 30 to 500 kPa. If the thickness of the hole blocking layer is less than 30 kW, the hole blocking property is not good and the efficiency is lowered. If the hole blocking layer is more than 500 kW, it is not preferable to increase the driving voltage.

It is common to use a phosphorescent dopant in forming the light emitting layer as described above, but it is selected from a carbazole compound, an oxadiazole compound, a phenanthroline compound, a phenanthroline compound, a triazine compound, and a triazole compound having hole transport properties as a host. In the case where more than one is used together, the hole blocking layer HBL may not be formed.

An electron transport layer is formed on the hole blocking layer to form an electron transport layer (ETL) using a method such as the above-described vacuum deposition method or spin coating. It does not restrict | limit especially as an electron carrying layer material, Alq3 can be used. It is preferable that the thickness of the said electron carrying layer is 50-600 GPa. If the thickness of the electron transport layer is less than 50 kW, the lifespan characteristics are lowered. If the electron transport layer is more than 600 kW, it is not preferable to increase the driving voltage.

In addition, an electron injection layer EIL may be selectively stacked on the electron transport layer. As the electron injection layer forming material, materials such as LiF, NaCl, CsF, Li ₂ O, BaO, and Liq can be used. It is preferable that the thickness of the said electron injection layer is 1-100 kPa. If the thickness of the electron injection layer is less than 1 kW, the driving voltage is not high because it does not serve as an effective electron injection layer, and if it exceeds 100 kW, the driving voltage acts as an insulating layer.

Subsequently, the cathode, which is the second electrode, is deposited on the electron injection layer using a method such as vacuum thermal layer deposition, sputtering, and metal-organic chemical vapor deposition. By forming, an organic electroluminescent element is completed.

The cathode metal is lithium (Li), magnesium (Mg), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag ) And the like are used.

In the organic electroluminescent device of the present invention, it is also possible to further form one or two intermediate layers according to the needs of the anode, the hole injection layer, the hole transport layer, the light emitting layer, the electron transport layer, the electron injection layer, and the cathode. In addition to the above-mentioned layers, a hole blocking layer and an electron blocking layer may also be included.

Hereinafter, the present invention will be described with reference to the following examples, but the present invention is not limited only to the following examples.

Example 1

The anode cuts a corning 15Ω / cm ² (1200Å) ITO glass substrate to 50mm x 50mm x 0.7mm and ultrasonically cleans for 5 minutes in isopropyl alcohol and pure water, followed by UV and ozone cleaning for 30 minutes. Was used.

N, N'-di (1-naphthyl) -N, N'-diphenylbenzidine (NPD) was vacuum deposited on the substrate to form a hole transport layer having a thickness of 600 kPa.

95 parts by weight of the host hole transport material 4,4'-biscarbazolylbiphenyl (CBP) and 5 parts by weight of phosphorescent dopant tris (2-phenylpyridine) iridium (Ir (ppy) ₃ ) were deposited on the hole transport layer. The first light emitting layer was formed to a thickness of about 100 GPa. 93 parts by weight of BAlq, which is an electron transporting material, and 7 parts by weight of Ir (ppy) ₃ , which is a phosphorescent dopant, were vacuum deposited on the first light emitting layer to form a second light emitting layer having a thickness of about 100 GPa. Subsequently, 95 parts by weight of CBP, which is a hole transport material, and 5 parts by weight of Ir (ppy) ₃ , which is a phosphorescent dopant, were vacuum deposited on the second light emitting layer to form a third light emitting layer having a thickness of about 100 μs.

Alq3, an electron transporting material, was deposited on the emission layer to form an electron transporting layer having a thickness of about 300 kHz.

LiF 10 전극 (electron injection layer) and Al 1000 Å (cathode) were sequentially vacuum deposited on the electron transport layer to form a LiF / Al electrode, thereby manufacturing an organic EL device as shown in FIG. 1.

Comparative Example 1

The anode cuts a corning 15Ω / cm ² (1200Å) ITO glass substrate to 50mm x 50mm x 0.7mm and ultrasonically cleans for 5 minutes in isopropyl alcohol and pure water, followed by UV and ozone cleaning for 30 minutes. Was used.

NPD was vacuum deposited on the substrate to form a hole transport layer having a thickness of 600 kHz. 5 parts by weight of phosphorescent dopant tris (2-phenylpyridine) iridium (Ir (ppy) ₃ ) as a phosphorescent dopant was deposited on a host 4,4'-biscarbazolylbiphenyl (CBP) on the hole transport layer to a thickness of about 400 kPa. A single light emitting layer was formed.

Alq3, an electron transporting material, was deposited on the emission layer to form an electron transporting layer having a thickness of about 300 kHz.

LiF 10 전극 (electron injection layer) and Al 1000 Å (cathode) were sequentially vacuum deposited on the electron transport layer to form a LiF / Al electrode, thereby manufacturing an organic EL device as shown in FIG. 1.

In the organic EL device manufactured according to Example 1 and Comparative Example 1, the efficiency and lifespan characteristics were investigated.

As a result, the efficiency of the organic electroluminescent device of Comparative Example 1 was about 32 cd / A at 1,000 cd / m2, and the organic electroluminescent device of Example 1 was about 46 cd / A at 1,000 cd / m2, Comparative Example 1 Compared to the case, the efficiency is improved by 40%.

In addition, the lifespan characteristics are represented by the time when the initial emission luminance decreases by 50%. The organic electroluminescent device of Example 1 is 350 hours at 5,000 cd / m2, and the organic electroluminescent device of Comparative Example 1 is 5,000 cd / m2. As shown by 290 hours, Example 1 can be confirmed that the life characteristics improved by 20% compared to the case of Comparative Example 1.

By using the organic electroluminescent element of this invention, the efficiency and the lifetime characteristic of an organic electroluminescent element can be improved.

Claims (26)

In an organic electroluminescent device having a plurality of light emitting layers between a first electrode and a second electrode, The outermost layer adjacent to the electrode of the light emitting layer includes a phosphorescent dopant and a hole transporting material as a host, and at least one light emitting layer formed between the outermost layer includes the phosphorescent dopant and an electron transporting material as a host. EL device. The light emitting layer of claim 1, wherein the plurality of light emitting layers has a total of 25 light emitting layer structures, and an odd numbered light emitting layer from the first electrode or the second electrode includes a phosphorescent dopant and a hole transport material as a host, and the first electrode or And the even light emitting layer from the second electrode includes a phosphorescent dopant and an electron transport material as a host. The light emitting layer of claim 1, wherein the light emitting layer comprises a first light emitting layer including a phosphorescent dopant and a hole transporting material as a host, a second light emitting layer including a phosphorescent dopant and an electron transporting material as a host, and a hole transporting material as a phosphorescent dopant and a host. An organic electroluminescent element comprising a third light emitting layer. The organic electroluminescent device according to claim 1, wherein the hole transport material is an aryl amine compound. The organic electroluminescent device according to claim 1, wherein the hole transport material is a carbazol compound. The method of claim 5, wherein the carbazole compound is 1,3,5-tricarbazolylbenzene, 4,4'-biscarbazolylbiphenyl, polyvinylcarbazole, m-biscarbazolylphenyl, 4,4'- Biscarbazolyl-2,2'-dimethylbiphenyl, 4,4 ', 4 "-tri (N-carbazolyl) triphenylamine, 1,3,5-tri (2-carbazolylphenyl) benzene, 1, An organic electroluminescent device, characterized in that at least one selected from the group consisting of 3,5-tris (2-carbazolyl-5-methoxyphenyl) benzene and bis (4-carbazolylphenyl) silane. The organic electric field of claim 1, wherein the electron transport material is at least one compound selected from organometallic complexes, spirofluorene compounds, oxadiazole compounds, phenanthroline compounds, triazine compounds, and triazole compounds. Light emitting element. 8. The method of claim 7, wherein the organometallic complex is a bis (8-hydroxyquinolato) biphenoxy metal, a bis (8-hydroxyquinolato) phenoxy metal, bis (2-methyl-8-hydroxy Quinolato) biphenoxy metal, bis (2-methyl-8-hydroxyquinolato) phenoxy metal), bis (2-methyl-8-quinolinolato) (para-phenyl-phenololato) metal And bis (2- (2-hydroxyphenyl) quinolato) metal, and the metal is Al, Zn, Be, or Ga. 8. The method of claim 7, wherein the organometallic complex is bis (8-hydroxyquinolato) biphenoxy aluminum, bis (8-hydroxyquinolato) phenoxy aluminum, bis (2-methyl-8-hydroxy Quinolato) biphenoxy aluminum, bis (2-methyl-8-hydroxyquinolato) phenoxy aluminum, bis (2- (2-hydroxyphenyl) quinolato) zinc, or bis (2-methyl -8-quinolinolato) (para-phenyl-phenolato) aluminum. According to claim 7, wherein the spirofluorene (spirofluorene) compound is a structure having a linking ring between two spirofluorene, the linkage is substituted with triazole, oxadiazole, naphthalene, anthracene, or phenyl And position 9 of each fluorene is a structure substituted with O, S, Se, NR, or PR, or a structure in which NR or PR directly connects two spirofluorenes, and each R is H, Or an aryl group having 6 to 20 carbon atoms having an alkyl group having 1 to 20 carbon atoms, an aryl group having 5 to 20 carbon atoms having 1 to 20 carbon atoms, a heteroaryl group having 2 to 20 carbon atoms, and an alkoxy group having 1 to 20 carbon atoms. An organic electroluminescent device, characterized in that the substituent is selected from the group. The method of claim 7, wherein the spirofluorene-based compound is characterized in that 2,5-disspirobifluorene-1,3,4-oxadiazole (2,5-Dispirobifluorene-1,3,4-oxadiazole) An organic electroluminescent element. The organic electroluminescent device according to claim 7, wherein the oxadiazole compound is (4-biphenylyl) -5- (4-tertbutylphenyl) -1,3,4-oxadiazole. The organic electroluminescent device according to claim 7, wherein the phenanthroline compound is 2,9-dimethyl-4,7-diphenyl-9,10-phenanthroline. The method of claim 7, wherein the triazine-based compound is 2,4,6-tris (diarylamino) -1,3,5-triazine, 2,4,6-tris (diphenylamino) -1,3, 5-triazine, 2,4,6-tricarbazolo-1,3,5-triazine, 2,4,6-tris (N-phenyl-2-naphthylamino) -1,3,5-tri Azine, 2,4,6-tris (N-phenyl-1-naphthylamino) -1,3,5-triazine, 2,4,6-trisbiphenyl-1,3,5-triazine, The triazole compound is 3-phenyl-4- (1'-naphthyl) -5-phenyl-1,2,4-triazole. The phosphorescent dopant in the light emitting layer is bistynylpyridine acetylacetonate iridium, bis (benzothienylpyridine) acetylacetonate iridium, bis (2-phenylbenzothiazole) acetylacetonate. At least one selected from the group consisting of iridium, bis (1-phenylisoquinoline) iridium acetylacetonate, tris (1-phenylisoquinoline) iridium, and tris (2-phenylpyridine) iridium. The organic electroluminescent device according to claim 3, wherein the first light emitting layer and the third light emitting layer comprise a carbazole compound as a host and an iridium complex as a phosphorescent dopant. The organic electroluminescent device according to claim 3, wherein the second light emitting layer comprises an organometallic complex as a host and an iridium complex as a phosphorescent dopant. The method of claim 16, wherein the carbazole compound is 4,4'-biscarbazolylbiphenyl (CBP), the iridium complex is tris (2-phenylpyridine) iridium (Ir (ppy) ₃ ) characterized in that Organic electroluminescent device. The organic electroluminescent device according to claim 1, wherein the content of the material used as the host in each of the light emitting layers is 50 to 99 parts by weight based on 100 parts by weight of the total weight of the light emitting layer forming material. The organic electroluminescent device according to claim 1, wherein the content of the hole transporting material in the outermost light emitting layer is 70 to 99 parts by weight based on 100 parts by weight of the light emitting layer forming material. The organic electroluminescent device according to claim 1, wherein the content of the electron transporting material in the light emitting layer formed between the outermost layers is 70 to 99 parts by weight based on 100 parts by weight of the light emitting layer forming material. The organic electroluminescent device according to claim 1, wherein the total thickness of the light emitting layers constituting the plurality of light emitting layers is 100 to 800 GPa. The organic electroluminescent device according to claim 3, wherein the thickness of the first light emitting layer and the third light emitting layer is 50 to 400 kPa. The organic electroluminescent device according to claim 3, wherein the second light emitting layer has a thickness of 50 to 400 kPa. The organic electroluminescent device according to claim 1, wherein at least one selected from a hole injection layer and a hole transport layer is stacked between the first electrode or the second electrode and the outermost layer of the light emitting layers. The organic electroluminescent device according to claim 1, wherein at least one selected from a hole blocking layer, an electron transport layer, and an electron injection layer is stacked between the first electrode or the second electrode and the outermost layer of the plurality of light emitting layers.

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