KR102275535B1 - Organic light emitting device - Google Patents

Abstract

The organic electroluminescent device according to an embodiment of the present invention is positioned between an anode and a cathode, a first light emitting part including a first light emitting layer and a first electron transport layer, is positioned on the first light emitting part, and a second light emitting layer and a second light emitting part including a second electron transport layer, and a charge generation layer disposed between the first light emitting part and the second light emitting part and including an N-type charge generation layer, the first electron transport layer and at least one of the second electron transport layer is made of any one of the electron transport compounds represented by Chemical Formulas 1 to 8, and the N-type charge generating layer is made of any one of the charge generating compounds represented by Chemical Formulas 9 and 10 .

Description

Organic light emitting device {ORGANIC LIGHT EMITTING DEVICE}

The present invention relates to an organic light emitting device, and more particularly, to an organic light emitting device capable of reducing a driving voltage and improving efficiency.

A video display device that implements various information on a screen is a key technology in the information and communication era, which is developing in the direction of thinner, lighter, more portable and high-performance. With the recent development of the information society, as the demand for various types of display devices increases, LCD (Liquid Crystal Display), PDP (Plasma Display Panel), ELD (Electro Luminescent Display), FED (Field Emission Display), OLED ( Organic Light Emitting Diode) and other flat panel display devices are being actively researched.

Among them, the organic light emitting device is a device that emits light while electrons and holes are paired and then disappear when electric charges are injected into the organic light emitting layer formed between the anode and the cathode. The organic electroluminescent device can be formed on a flexible transparent substrate such as plastic, and can be driven at a lower voltage than a plasma display panel or an inorganic electroluminescent (EL) display, and power consumption is relatively low. It has the advantage of being small and the color is excellent. In particular, the organic electroluminescent device for realizing white color is a device that is used for various purposes, such as a thin light source, a backlight of a liquid crystal display device, or a full-color display device employing a color filter as well as lighting.

In the development of white organic light emitting diodes, research and development are in progress according to each method because high efficiency and long lifespan, as well as color purity, color stability according to changes in current and voltage, and ease of device manufacturing are important. The structure of the white organic light emitting device can be broadly divided into a single layer light emitting structure, a multilayer light emitting structure, and the like. Among these, a multilayer light emitting structure in which a fluorescent blue light emitting layer and a phosphorescent yellow light emitting layer are stacked (tandem) for a white organic light emitting diode having a long lifespan is mainly adopted.

Specifically, a phosphorescent light emitting unit structure in which a first light emitting unit using a blue fluorescent element as a light emitting layer and a second light emitting unit structure using a yellow phosphorescent element as a light emitting layer are stacked is used. In such a white organic light emitting device, white light is realized by a mixing effect of blue light emitted from a blue fluorescent device and yellow light emitted from a yellow phosphorescent device. A charge generation layer is provided between the first light emitting unit and the second light emitting unit to double the efficiency of the current generated in the light emitting layer and to facilitate charge distribution. The charge generation layer includes an N-type charge generation layer and a P-type charge generation layer.

However, in the device having the above-described multilayer light emitting structure, the driving voltage of the entire device having the multilayer light emitting structure may be greater than the sum of the driving voltages of the respective light emitting units, or the efficiency of the device may be reduced compared to the light emitting device having a single layer. In particular, when the N-type charge generation layer is doped with an alkali metal or alkaline earth metal, the device lifetime may be reduced. In addition, due to the difference in LUMO (Lowest Unoccupied Molecular Orbital) energy level between the N-type charge generating layer and the P-type charge generating layer, electrons generated between the P-type charge generating layer and the hole transport layer generate N-type charge. The layer-injected properties are degraded. Also, due to the difference in LUMO energy level between the electron transport layer and the N-type charge generation layer, the driving voltage increases when the electrons injected into the N-type charge generation layer move to the electron transport layer.

The present invention provides an organic electroluminescent device capable of reducing a driving voltage and improving luminous efficiency.

In order to achieve the above object, an organic electroluminescent device according to an embodiment of the present invention is positioned between an anode and a cathode, and includes a first light emitting part including a first light emitting layer and a first electron transport layer, the first light emitting part a second light emitting part including a second light emitting layer and a second electron transport layer, and a charge generating layer located between the first light emitting part and the second light emitting part, and including an N-type charge generating layer. wherein at least one of the first electron transport layer and the second electron transport layer is made of any one of the electron transport compounds represented by the following Chemical Formulas 1 to 8, and the N-type charge generating layer is a charge represented by the following Chemical Formulas 9 and 10 It is characterized in that it consists of any one of the product compounds.

[Formula 1]

[Formula 2]

[Formula 3]

[Formula 4]

In Formulas 1 to 4, R ₂₁ to R ₃₃ are each independently hydrogen, a substituted or unsubstituted aryl group having 6 to 60 carbon atoms, a substituted or unsubstituted heteroaryl group having 4 to 60 carbon atoms, or 1 to 10 carbon atoms An alkyl group, any one of an alkoxy group having 1 to 10 carbon atoms, R ₂₁ and R ₂₂ , R ₂₃ and R ₂₄ , R ₂₅ and R ₂₆ , R ₂₇ and R ₂₈ , R ₂₉ and R ₃₀ , and R ₃₁ and R ₃₂ At least one of them may be bonded to each other to form a ring, and X ₁₀ to X ₂₂ are each independently C or N,

[Formula 5]

[Formula 6]

[Formula 7]

[Formula 8]

In Formulas 5 to 8, R ₂₁ to R ₃₃ are each independently hydrogen, a substituted or unsubstituted aryl group having 6 to 60 carbon atoms, a substituted or unsubstituted heteroaryl group having 4 to 60 carbon atoms, or 1 to 10 carbon atoms An alkyl group, any one of an alkoxy group having 1 to 10 carbon atoms, R ₂₁ and R ₂₂ , R ₂₃ and R ₂₄ , R ₂₅ and R ₂₆ , R ₂₈ and R ₂₉ , R ₂₇ and R ₃₁ , R ₂₉ and R ₃₀ , At least one of R ₃₁ and R ₃₂ , R ₃₂ and R _{33 ,} and R ₃₀ and R ₃₃ may be bonded to each other to form a ring, and X ₁₀ to X ₂₂ are each independently C or N;

[Formula 9]

[Formula 10]

In Formulas 9 and 10, at least one of _{X 1} to X _{4 and X 5} to X ₉ at least one includes at least one of S, O, N and Si, and L is a single bond, a substituted or unsubstituted C6-20 arylene group, or a substituted or unsubstituted C4-20C20 heteroarylene group Any one, in Formula 9, R _{2 To} R ₉ are each independently hydrogen, a substituted or unsubstituted C6 to C60 aryl group, a substituted or unsubstituted C6 to C60 heteroaryl group, C1 to 10 alkyl group, or any one of a C 1 to C 10 alkoxy group, in Formula 10, R ₁₀ to R ₁₈ are each independently hydrogen, a substituted or unsubstituted C 6 to C 60 aryl group, substituted or unsubstituted Any one of a heteroaryl group having 6 to 60 carbon atoms, an alkyl group having 1 to 10 carbon atoms, and an alkoxy group having 1 to 10 carbon atoms.

In addition, the organic electroluminescent device according to an embodiment of the present invention is positioned between the anode and the cathode, the first light emitting part including the first light emitting layer and the first electron transport layer, is positioned on the first light emitting part, the second A second light emitting unit including a light emitting layer and a second electron transport layer, located on the second light emitting unit, a third light emitting unit including a third light emitting layer and a third electron transport layer, the first light emitting unit and the second light emitting unit A first charge generating layer positioned therebetween, and a second charge generating layer positioned between the second light emitting part and the third light emitting part, wherein the first electron transport layer, the second electron transport layer, and the third electron transport layer At least one of them includes the electron transport compound, and at least one of the first charge generation layer and the second charge generation layer includes the charge generation compound.

In addition, the organic electroluminescent device according to an embodiment of the present invention is positioned between the anode and the cathode, and at least two light emitting units including a light emitting layer and an electron transport layer, respectively, and a charge generating layer positioned between the at least two light emitting units. and at least one of the electron transport layers included in the light emitting units include the electron transport compound, and at least one of the charge generation layers includes the charge generation compound.

According to the present invention, at least one electron transport layer located in the light emitting part is composed of a phenanthroline compound and an anthracene or pyrene compound containing a carboline derivative is used in the N-type charge generating layer to form an electron transport layer or It facilitates the movement of electrons transferred to the light emitting layer.

In addition, the electron transport layer is composed of a phenanthroline compound and includes a phenanthroline ring containing nitrogen having many electrons, thereby facilitating the transport of electrons to the light emitting layer. And a triphenyl derivative is linked to phenanthroline, making it easier to move electrons from the adjacent N-type charge generating layer to the light emitting layer.

In addition, by using a pyrene compound or anthracene compound containing a carboline derivative in the N-type charge generation layer, the nitrogen of sp2 hybrid orbital, which is relatively rich in electrons in the carboline derivative, is an alkali metal or A gap state is formed by combining with an alkaline earth metal, and electrons are smoothly transferred from the P-type charge generating layer to the N-type charge generating layer by the gap state.

1 is a view showing an organic electroluminescent device according to a first embodiment of the present invention.
2 is a view showing an organic electroluminescent device according to a second embodiment of the present invention.
Figure 3 is an energy band diagram of the organic light emitting device of the present invention.

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the technical field to which the present invention belongs It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims.

The shapes, sizes, proportions, angles, numbers, etc. disclosed in the drawings for explaining the embodiments of the present invention are exemplary, and thus the present invention is not limited to the illustrated matters. Like reference numerals refer to like elements throughout. In addition, in describing the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. When 'including', 'having', 'consisting', etc. mentioned in this specification are used, other parts may be added unless 'only' is used. When a component is expressed in the singular, the case in which the plural is included is included unless otherwise explicitly stated.

In interpreting the components, it is interpreted as including an error range even if there is no separate explicit description.

In the case of a description of the positional relationship, for example, when the positional relationship of two parts is described as 'on', 'on', 'on', 'beside', etc., 'right' Alternatively, one or more other parts may be positioned between the two parts unless 'directly' is used.

In the case of a description of a temporal relationship, for example, 'immediately' or 'directly' when a temporal relationship is described with 'after', 'following', 'after', 'before', etc. It may include cases that are not continuous unless this is used.

Although the first, second, etc. are used to describe various components, these components are not limited by these terms. These terms are only used to distinguish one component from another. Accordingly, the first component mentioned below may be the second component within the spirit of the present invention.

Each feature of the various embodiments of the present invention may be partially or wholly combined or combined with each other, technically various interlocking and driving are possible, and each of the embodiments may be implemented independently of each other or may be implemented together in a related relationship. may be

Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing an organic electroluminescent device according to a first embodiment of the present invention.

Referring to FIG. 1 , in the organic light emitting device 100 of the present invention, the light emitting units ST1 and ST2 positioned between the anode 110 and the cathode 220 and the electric charge positioned between the light emitting units ST1 and ST2 are provided. and a generation layer 160 . The anode 110 is an electrode for injecting holes and may be any one of indium tin oxide (ITO), indium zinc oxide (IZO), and zinc oxide (ZnO) having a high work function. In addition, when the anode 110 is a reflective electrode, the anode 110 includes a reflective layer made of any one of aluminum (Al), silver (Ag), or nickel (Ni) under a layer made of any one of ITO, IZO, and ZnO. may include more.

The first light emitting part ST1 constitutes one light emitting device unit, and includes a first hole injection layer 120 , a first hole transport layer 130 , a blue light emitting layer 140 , and a first electron transport layer 150 . do. Here, the blue light emitting layer 140 includes one of a blue light emitting layer, a dark blue light emitting layer, or a sky blue light emitting layer.

The first hole injection layer 120 may serve to smoothly inject holes from the anode 110 to the blue light emitting layer 140 , and may include cupper phthalocyanine (CuPc) and poly(3,4)-ethylenedioxythiophene (PEDOT). , PANI (polyaniline) and NPD (N,N-dinaphthyl-N,N'-diphenyl benzidine) may consist of any one or more selected from the group consisting of, but is not limited thereto. The thickness of the first hole injection layer 120 may be 1 to 150 nm. Here, if the thickness of the first hole injection layer 120 is 1 nm or more, hole injection characteristics can be improved, and if it is 150 nm or more, the thickness of the first hole injection layer 120 is too thick. An increase in the driving voltage can be prevented. The first hole injection layer 120 may not be included in the configuration of the organic light emitting diode depending on the structure or characteristics of the device.

The first hole transport layer 130 serves to facilitate hole transport, and NPD (N,N-dinaphthyl-N,N'-diphenyl benzidine), TPD (N,N'-bis-(3-methylphenyl) )-N,N'-bis-(phenyl)-benzidine), s-TAD and MTDATA(4,4',4"-Tris(N-3-methylphenyl-N-phenyl-amino)-triphenylamine) may be made of any one or more selected from, but is not limited thereto. The thickness of the first hole transport layer 130 may be 1 to 150 nm. Here, if the thickness of the first hole transport layer 130 is 1 nm or more, hole transport Characteristics may be improved, and if the thickness is 150 nm or more, the increase of the driving voltage for improving hole movement may be prevented because the thickness of the first hole transport layer 130 is too thick.

The blue light emitting layer 140 may include a host material including CBP or mCP, and may be formed of a phosphor material including a dopant material including _{(4,6-F 2} ppy) _{2 Irpic.} DPVBi, spiro-6P, distylbenzene (DSB), distrylarylene (DSA), may be made of a fluorescent material including any one selected from the group consisting of PFO-based polymers and PPV-based polymers, but is not limited thereto.

The first electron transport layer 150 serves to facilitate the transport of electrons, and affects the lifespan and efficiency of the organic light emitting diode. Accordingly, the inventors of the present invention conducted various experiments to improve the electron injection characteristics of the electron transport layer. A phenanthroline compound was introduced into the electron transport layer through various experiments on materials that do not affect the lifespan, efficiency, or driving voltage of the organic light emitting diode by the combination of the electron transport layer and the charge generation layer. Phenanthroline compounds include p-terphenyl derivatives. The phenanthroline compound facilitates the transport of electric charges through the aromatic ring in the molecule, and in particular, as it contains nitrogen (N) with many electrons like the phenanthroline ring, it prevents the transport of electrons to the light emitting layer. make it easy In addition, since a triphenyl derivative is connected to the phenanthroline derivative, the electrons are smoothly moved from the adjacent N-type charge generating layer to the light emitting layer.

Accordingly, the electron transport layer is made of any one of the electron transport compounds represented by the following Chemical Formulas 1 to 8. The electron transport compound includes a phenanthroline derivative and a triphenyl derivative.

[Formula 1]

[Formula 2]

[Formula 3]

[Formula 4]

In Formulas 1 to 4, R ₂₁ to R ₃₃ are each independently hydrogen, a substituted or unsubstituted aryl group having 6 to 60 carbon atoms, a substituted or unsubstituted heteroaryl group having 4 to 60 carbon atoms, or 1 to 10 carbon atoms An alkyl group, any one selected from an alkoxy group having 1 to 10 carbon atoms, R ₂₁ and R ₂₂ , R ₂₃ and R ₂₄ , R ₂₅ and R ₂₆ , R ₂₇ and R ₂₈ , R ₂₉ and R ₃₀ , and R ₃₁ and R ₃₂ may combine with each other to form a ring, and X ₁₀ to X ₂₂ are each independently C or N.

[Formula 5]

[Formula 6]

[Formula 7]

[Formula 8]

In Formulas 5 to 8, R ₂₁ to R ₃₃ are each independently hydrogen, a substituted or unsubstituted aryl group having 6 to 60 carbon atoms, a substituted or unsubstituted heteroaryl group having 4 to 60 carbon atoms, or 1 to 10 carbon atoms An alkyl group, any one of an alkoxy group having 1 to 10 carbon atoms, R ₂₁ and R ₂₂ , R ₂₃ and R ₂₄ , R ₂₅ and R ₂₆ , R ₂₈ and R ₂₉ , R ₂₇ and R ₃₁ , R ₂₉ and R ₃₀ , At least one of R ₃₁ and R ₃₂ , R ₃₂ and R _{33 ,} and R ₃₀ and R ₃₃ may be bonded to each other to form a ring, and X ₁₀ to X ₂₂ are each independently C or N.

In more detail, the electron transport compound represented by Formulas 1 to 4 may have a molecular weight of 400 or more, and may be any one of compounds represented by Formulas 11 to 14 below.

[Formula 11]

[Formula 12]

[Formula 13]

[Formula 14]

In Formulas 11 to 14, R ₂₁ to R ₃₃ are each independently hydrogen, a substituted or unsubstituted aryl group having 6 to 60 carbon atoms, a substituted or unsubstituted heteroaryl group having 4 to 60 carbon atoms, and 1 to 10 carbon atoms An alkyl group, any one of an alkoxy group having 1 to 10 carbon atoms, R ₂₁ and R ₂₂ , R ₂₃ and R ₂₄ , R ₂₅ and R ₂₆ , R ₂₇ and R ₂₈ , R ₂₉ and R ₃₀ , and R ₃₁ and R ₃₂ At least one of them may be bonded to each other to form a ring.

In addition, the electron transport compound represented by Formulas 5 to 8 may be any one of compounds represented by Formulas 15 to 18 below.

[Formula 15]

[Formula 16]

[Formula 17]

[Formula 18]

In Formulas 15 to 18, R ₂₁ to R ₃₃ are each independently hydrogen, a substituted or unsubstituted aryl group having 6 to 60 carbon atoms, a substituted or unsubstituted heteroaryl group having 4 to 60 carbon atoms, and 1 to 10 carbon atoms An alkyl group, any one of an alkoxy group having 1 to 10 carbon atoms, R ₂₁ and R ₂₂ , R ₂₃ and R ₂₄ , R ₂₅ and R ₂₆ , R ₂₈ and R ₂₉ , R ₂₇ and R ₃₁ , R ₂₉ and R ₃₀ , At least one of R ₃₁ and R ₃₂ , R ₃₂ and R ₃₃ , and R ₃₀ and R ₃₃ may be bonded to each other to form a ring.

The electron transport compound may be any one selected from the compounds shown below.

Meanwhile, a charge generation layer (CGL) 160 is positioned on the first light emitting part ST1 . The first light emitting part ST1 and the second light emitting part ST2 have a structure connected by the charge generation layer 160 . The charge generation layer 160 may be a PN junction charge generation layer in which an N-type charge generation layer 160N and a P-type charge generation layer 160P are joined. At this time, the PN junction charge generation layer 160 generates charges or separates them into holes and electrons to inject charges into each of the light emitting layers. That is, the N-type charge generation layer 160N supplies electrons to the blue light-emitting layer 140 adjacent to the anode, and the P-type charge generation layer 160P supplies holes to the light-emitting layer of the second light-emitting part ST2. The luminous efficiency of the organic light emitting diode having a plurality of light emitting layers can be further increased, and the driving voltage can also be lowered. Accordingly, the charge generation layer 160 has an important influence on the luminous efficiency or driving voltage, which are characteristics of the organic light emitting diode.

Accordingly, the inventors of the present invention conducted various experiments to improve the electron injection characteristics of the charge generation layer. Through various experiments, an anthracene compound and a pyrene compound were introduced into the host included in the charge generation layer. The anthracene compound and the pyrene compound each include a carboline derivative. The pyrene compound and the anthracene compound contain nitrogen (N) in the sp2 hybrid orbital, which is relatively rich in electrons in the carboline derivative. This nitrogen binds to an alkali metal or alkaline earth metal, which is a dopant of the N-type charge generation layer, to form a gap state. By the formed gap state, electrons can be smoothly transferred from the P-type charge generation layer to the N-type charge generation layer.

Accordingly, the N-type charge generating layer 160N includes a host and a dopant, and the host may be formed of a charge generating compound represented by Chemical Formulas 9 and 10 below.

[Formula 9]

[Formula 10]

In Formulas 9 and 10, at least one of _{X 1} to X _{4 and X 5} to X ₉ at least one includes at least one of S, O, N and Si, and L is a single bond, a substituted or unsubstituted C6-20 arylene group, or a substituted or unsubstituted C4-20C20 heteroarylene group any one selected from In addition, in Formula 5, R ₂ to R ₉ are each independently hydrogen, a substituted or unsubstituted aryl group having 6 to 60 carbon atoms, a substituted or unsubstituted heteroaryl group having 6 to 60 carbon atoms, and 1 to 10 carbon atoms an alkyl group, any one selected from an alkoxy group having 1 to 10 carbon atoms, in Formula 6, R ₁₀ to R ₁₈ are each independently hydrogen, a substituted or unsubstituted C 6 to C 60 aryl group, or a substituted or unsubstituted carbon number Any one selected from a heteroaryl group having 6 to 60 carbon atoms, an alkyl group having 1 to 10 carbon atoms, and an alkoxy group having 1 to 10 carbon atoms.

The charge generating compound represented by Formula 9 or 10 may be represented by Formula 19 or 20 below.

[Formula 19]

[Formula 20]

In Formulas 19 and 20, _{at least one of X 1} to X ₄ and at least one of X ₅ to X ₉ include at least one of S, O, N and Si, and L is a single bond, substituted or unsubstituted an arylene group having 6 to 20 carbon atoms or a substituted or unsubstituted hetero arylene group having 4 to 20 carbon atoms, in Formula 19, R ₁₉ is hydrogen, a substituted or unsubstituted aryl group having 6 to 60 carbon atoms, substituted or unsubstituted is any one of an unsubstituted heteroaryl group having 4 to 60 carbon atoms, an alkyl group having 1 to 10 carbon atoms, and an alkoxy group having 1 to 10 carbon atoms, in Formula 20, R ₂₀ is hydrogen, a substituted or unsubstituted C 6 to C60 aryl group group, a substituted or unsubstituted heteroaryl group having 4 to 60 carbon atoms, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms.

The charge generating compound of the N-type charge generating layer 160N may be any one selected from the compounds shown below.

The n-type charge generation layer 160N includes a dopant. Here, the dopant may be an alkali metal, an alkali metal compound, an alkaline earth metal or an alkaline earth metal compound. In detail, the dopant may be at least one selected from the group consisting of Li, Cs, K, Rb, Mg, Na, Ca, Sr, Eu and Yb. The proportion of the dopant is mixed in an amount of 1 to 8% with respect to 100% of the entire host. Here, the work function of the dopant is preferably 2.5 eV or more.

Meanwhile, the P-type charge generation layer 160P may be formed of a metal or an organic material doped with a P-type. Here, the metal may be made of one or two or more alloys selected from the group consisting of Al, Cu, Fe, Pb, Zn, Au, Pt, W, In, Mo, Ni and Ti. In addition, as the P-type dopant and the host material used in the P-type doped organic material, a commonly used material may be used. For example, the P-type dopant may include 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ), a derivative of tetracyanoquinodimethane, iodine , FeCl ₃ , FeF ₃ and SbCl _{5 It} may be one material selected from the group consisting of. In addition, the host is N,N'-di(naphthalen-1-yl)-N,N-diphenyl-benzidine (NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl) It may be one material selected from the group consisting of -1,1-biphenyl-4,4'-diamine (TPD) and N,N',N'-tetranaphthyl-benzidine (TNB).

Meanwhile, a second hole injection layer 170 , a second hole transport layer 180 , a yellow light emitting layer 190 , a second electron transport layer 200 and an electron injection layer 210 are included on the charge generation layer 160 . A second light emitting unit ST2 is positioned. The second hole injection layer 170 , the second hole transport layer 180 , and the second electron transport layer 200 are the first hole injection layer 120 and the first hole transport layer 130 of the first light emitting part ST1 described above. ) and the configuration of the first electron transport layer 150 may be the same as or different from those of the first electron transport layer 150 .

The yellow light emitting layer 190 may have a yellow-green light emitting layer or a multilayer structure of a yellow-green light emitting layer and a green light emitting layer. Here, the yellow light emitting layer 190 includes a yellow-green light emitting layer or a multilayer structure of a yellow-green light emitting layer and a green light emitting layer. In this embodiment, a single-layer structure of a yellow light emitting layer emitting yellow green will be described as an example. The yellow light emitting layer 190 is CBP (4,4'-N,N'-dicarbazolebiphenyl) or Balq (Bis(2-methyl-8-quinlinolato-N1,O8)-(1,1'-Biphenyl-4-olato) aluminum) and may be made of a phosphorescent yellow-green dopant that emits yellow green to at least one host selected from among them.

The second electron transport layer 200 may be formed the same as or different from the above-described first electron transport layer 150 . When the second electron transport layer 200 is formed differently from the first electron transport layer 150 , the second electron transport layer 200 includes Alq3 (tris(8-hydroxyquinolino)aluminum), PBD, TAZ, spiro-PBD, BAlq, and SAlq. It may consist of any one or more selected from the group consisting of, but is not limited thereto. The thickness of the second electron transport layer 200 may be 1 to 50 nm. Here, if the thickness of the second electron transport layer 200 is 1 nm or more, there is an advantage in that the electron transport characteristics can be prevented from being lowered, and if it is 50 nm or more, the thickness of the second electron transport layer 200 is too thick, so that the movement of electrons is restricted. There is an advantage in that it is possible to prevent the increase of the driving voltage for improvement.

The electron injection layer 210 serves to facilitate electron transport, and Alq ₃ (tris(8-hydroxyquinolino)aluminum), PBD, TAZ, spiro-PBD, BAlq, or SAlq may be used, but is not limited thereto. . On the other hand, the electron injection layer 210 may be formed of a metal compound, a metal compound, for example LiQ, LiF, NaF, KF, RbF, CsF, FrF, BeF _2, MgF _2, CaF _2, SrF _2, BaF ₂ And RaF _{2 It} may be any one or more selected from the group consisting of, but is not limited thereto. The electron injection layer 210 may have a thickness of 1 to 50 nm. Here, if the thickness of the electron injection layer 210 is 1 nm or more, there is an advantage in that the electron injection characteristic can be prevented from being deteriorated, and if it is 50 nm or less, the thickness of the electron injection layer 210 is too thick to prevent electron movement There is an advantage in that it is possible to prevent the driving voltage from being raised to improve it. Accordingly, the second hole injection layer 170, the second hole transport layer 180, the yellow light emitting layer 190, the second electron transport layer 200 and the electron injection layer 210 on the charge generation layer 160, including The second light emitting unit ST2 is formed.

The cathode 220 is positioned on the second light emitting part ST2. The cathode 220 is an electron injection electrode, and may be made of magnesium (Mg), calcium (Ca), aluminum (Al), silver (Ag), or an alloy thereof having a low work function. Here, the cathode 220 may be formed to be thin enough to transmit light when the organic light emitting device has a front or double-sided light emitting structure, and when the organic light emitting device has a rear light emitting structure, it can reflect light. It can be formed as thick as possible.

As described above, the present invention uses a phenanthroline compound for at least one electron transport layer included in the light emitting part and an anthracene or pyrene compound for the N-type charge generation layer, thereby forming an electron transport layer and a light emitting layer from the N-type charge generation layer. It facilitates the movement of electrons transferred to

In addition, the electron transport layer is composed of a phenanthroline compound and includes a phenanthroline ring containing nitrogen, thereby facilitating the transport of electrons to the light emitting layer. And since the triphenyl derivative is connected to the phenanthroline derivative, the electrons from the N-type charge generating layer to the light emitting layer are more easily moved.

In addition, by using a pyrene compound or anthracene compound containing a carboline derivative in the N-type charge generation layer, the nitrogen of sp2 hybrid orbital, which is relatively rich in electrons in the carboline derivative, is an alkali metal or A gap state is formed by combining with an alkaline earth metal, and electrons are smoothly transferred from the P-type charge generating layer to the N-type charge generating layer by the gap state.

2 is a view showing an organic electroluminescent device according to a second embodiment of the present invention. Hereinafter, the same reference numerals are assigned to the same components as those of the first embodiment, and descriptions thereof will be omitted.

Referring to FIG. 2 , the organic light emitting device 100 of the present invention includes a plurality of light emitting units ST1 , ST2 , ST3 and a plurality of light emitting units ST1 and ST2 positioned between the anode 110 and the cathode 220 . , ST3) and a first charge generation layer 160 and a second charge generation layer 230 positioned between. In the present embodiment, it has been illustrated and described that three light emitting units are positioned between the anode 110 and the cathode 220 , but the present invention is not limited thereto and four or more light emitting units are disposed between the anode 110 and the cathode 220 . may include

In more detail, the first light emitting unit ST1 constitutes one light emitting device unit and includes the first light emitting layer 140 . The first light emitting layer 140 may emit any one color among red, green, and blue, and in this embodiment may be a blue light emitting layer that emits blue. The first light emitting part ST1 further includes a first hole injection layer 120 and a first hole transport layer 130 between the anode 110 and the first light emitting layer 140 . In addition, the first light emitting part ST1 further includes a first electron transport layer 150 on the first light emitting layer 140 . Accordingly, the first light emitting part ST1 including the first hole injection layer 120 , the first hole transport layer 130 , the first light emitting layer 140 , and the first electron transport layer 150 on the anode 110 is formed. make up The first hole injection layer 120 and the first hole transport layer 130 may not be included in the configuration of the first light emitting part ST1 depending on the structure or characteristics of the device.

The first electron transport layer 150 is made of a phenanthroline compound in the same manner as in the first embodiment described above. The phenanthroline compound facilitates the transport of electric charges through the aromatic ring in the molecule, and in particular, since electron-rich nitrogen is included like the phenanthroline ring, it facilitates the transport of electrons to the light emitting layer. In addition, since the triphenyl derivative is connected to the phenanthroline derivative, the electrons are smoothly moved from the N-type charge generating layer to the light emitting layer.

A first charge generation layer 160 is positioned on the first light emitting part ST1. The first charge generation layer 160 is a PN junction charge generation layer in which an N-type charge generation layer 160N and a P-type charge generation layer 160P are joined, and generates charges or separates them into holes and electrons in each light emitting layer. inject an electric charge Here, the N-type charge generation layer 160N is made of a pyrene compound or an anthracene compound. By introducing a pyrene compound or anthracene compound including a carboline derivative into the N-type charge generation layer 160N, nitrogen of an sp2 hybrid orbital, which is relatively rich in electrons in the carboline derivative, is an alkali metal contained in the N-type charge generation layer. Alternatively, a gap state is formed by combining with an alkaline earth metal, and electrons are smoothly transferred from the P-type charge generating layer to the N-type charge generating layer by the gap state. Accordingly, since electrons can move rapidly to the first light emitting layer 140 , the electron injection capability of the organic light emitting diode can be improved and the driving voltage can be reduced. The P-type charge generation layer 160P has the same configuration as in the first embodiment described above.

Meanwhile, the second light emitting part ST2 including the second light emitting layer 190 is positioned on the first charge generating layer 160 . The second light emitting layer 190 may emit one color among red, green, and blue. For example, in the present embodiment, the second light emitting layer 190 may be a yellow light emitting layer that emits yellow. The yellow light emitting layer may have a yellow-green light emitting layer or a multilayer structure of a yellow-green light emitting layer and a green light emitting layer. The second light emitting part ST2 further includes a second hole injection layer 170 and a second hole transport layer 180 between the first charge generating layer 160 and the second light emitting layer 190 , and a second A second electron transport layer 200 is further included on the light emitting layer 190 . Since the second electron transport layer 200 is formed in the same manner as the first electron transport layer 150 , a description thereof will be omitted. Accordingly, the second light emitting unit including the second hole injection layer 170 , the second hole transport layer 180 , the second emission layer 190 , and the second electron transport layer 200 on the first charge generation layer 160 . (ST2) is constructed.

A second charge generation layer 230 is positioned on the second light emitting part ST2. The second charge generation layer 230 is a PN junction charge generation layer in which an N-type charge generation layer 230N and a P-type charge generation layer 230P are joined, and generates charges or separates them into holes and electrons in each of the light emitting layers. inject an electric charge Here, since the N-type charge generation layer 230N is formed in the same manner as the N-type charge generation layer 160N of the first charge generation layer 160 , a description thereof will be omitted. Also, the P-type charge generation layer 230P has the same configuration as the P-type charge generation layer 160P of the first charge generation layer 160 described above.

A third light emitting part ST3 including a third light emitting layer 250 is positioned on the second charge generating layer 230 . The third light emitting layer 250 may emit one color among red, green, and blue, for example, a blue light emitting layer that emits blue in the present embodiment. The blue light emitting layer includes one of a blue light emitting layer, a dark blue light emitting layer, or a sky blue light emitting layer. The third light emitting part ST3 further includes a third hole transport layer 240 between the second charge generating layer 230 and the third light emitting layer 250 , and the third electrons on the third light emitting layer 250 . It further includes a transport layer 260 and an electron injection layer 210 . Since the third electron transport layer 260 is formed in the same manner as the above-described first electron transport layer 150 and the second electron transport layer 200 , a description thereof will be omitted. Accordingly, the third light emitting part ST3 including the third hole transport layer 240 , the third emission layer 250 , the third electron transport layer 260 , and the electron injection layer 210 on the second charge generation layer 230 . ) constitutes A cathode 220 is provided on the third light emitting part ST3 to configure the organic electroluminescent device according to the second embodiment of the present invention.

In the second embodiment of the present invention described above, it has been described that the first electron transport layer 150 , the second electron transport layer 200 , and the third electron transport layer 260 all have the same configuration. However, the present invention is not limited thereto, and at least one of the first electron transport layer 150 , the second electron transport layer 200 , and the third electron transport layer 260 is made of a phenanthroline compound. The phenanthroline compound facilitates the transport of electric charge through the aromatic ring in the molecule, and in particular, the electron-rich nitrogen is included as in the phenanthroline ring, thereby facilitating the transport of electrons. In addition, since the triphenyl derivative is connected to the phenanthroline derivative, the electrons are smoothly moved from the adjacent N-type charge generating layer to the light emitting layer.

In addition, in the second embodiment of the present invention, both the N-type charge generation layer 160N of the first charge generation layer 160 and the N-type charge generation layer 230N of the second charge generation layer 230 have the same configuration. described as being done. However, the present invention is not limited thereto, and at least one of the N-type charge generation layer 160N of the first charge generation layer 160 and the N-type charge generation layer 230N of the second charge generation layer 230 includes a carboline derivative. It consists of an anthracene compound or a pyrene compound. The pyrene compound and the anthracene compound contain nitrogen in the sp2 hybrid orbital, which is relatively rich in electrons in the carboline derivative. This nitrogen is combined with an alkali metal or alkaline earth metal, which is a dopant of the N-type charge generation layer, to form a gap state. Therefore, by the gap state, electrons can be smoothly transferred from the P-type charge generation layer to the N-type charge generation layer.

3 is an energy band diagram of an organic light emitting diode according to an embodiment of the present invention.

Referring to FIG. 3 , the organic electroluminescent device of the present invention includes a hole transport layer (HTL), a P-type charge generation layer (P-CGL), an N-type charge generation layer (N-CGL) and an electron transport layer (ETL). . The N-type charge generation layer (N-CGL) supplies electrons to the adjacent electron transport layer (ETL), and the P-type charge generation layer (P-CGL) supplies holes to the adjacent hole transport layer (HTL). In the N-type charge generation layer (N-CGL), nitrogen of an sp2 hybrid orbital is included in the carboline derivative, and this nitrogen is combined with an alkali metal or alkaline earth metal, which is a dopant of the N-type charge generation layer, to form a gap state. do. Accordingly, electrons may be smoothly transferred from the P-type charge generation layer (P-CGL) to the N-type charge generation layer (N-CGL) by the gap state. In addition, the electron transport layer (ETL) contains a phenanthroline compound and facilitates the transport of electric charges through an aromatic ring in the molecule, and in particular, since it contains nitrogen rich in electrons like the phenanthroline ring, the transport of electrons to the light emitting layer is facilitated. make it easy In addition, since the triphenyl derivative is connected to the phenanthroline derivative, it facilitates the movement of electrons from the N-type charge generating layer to the electron transport layer. Accordingly, the electron injection capability of the device is improved, thereby lowering the driving voltage of the device and improving the luminous efficiency.

Hereinafter, an embodiment in which the organic electroluminescent device of the present invention is manufactured is disclosed. The following materials for the electron transport layer and the N-type charge generation layer are not intended to limit the scope of the present invention.

<Comparative Example 1>

A first light emitting unit including a blue light emitting layer and a first electron transport layer, an N-type charge generation layer, a P type charge generation layer, a second light emitting unit including a yellow light emitting layer and a second electron transport layer, and a cathode are formed on the ITO substrate, An organic electroluminescent device was manufactured. Here, the first electron transport layer was formed of the following compound ETL_R1, and the N-type charge generation layer was formed of the following compound NCGL_R.

<Comparative Example 2>

In the same configuration as in Comparative Example 1 described above, the first electron transport layer was formed of the following compound ETL_A, and the N-type charge generation layer was formed of the compound NCGL_R to manufacture an organic electroluminescent device.

<Comparative Example 3>

In the same configuration as in Comparative Example 1 described above, the first electron transport layer was formed of the compound ETL_R1, and the N-type charge generation layer was formed of the following compound NCGL_B to manufacture an organic electroluminescent device.

<Comparative Example 4>

In the same configuration as in Comparative Example 1, the first electron transport layer was formed of the following compound ETL_R2, and the N-type charge generation layer was formed of the following compound NCGL_C to manufacture an organic electroluminescent device.

<Example 1>

In the same configuration as in Comparative Example 1, the first electron transport layer was formed of the compound ETL_A, and the N-type charge generation layer was formed of the compound NCGL_B to fabricate an organic electroluminescent device.

<Example 2>

In the same configuration as in Comparative Example 1, the first electron transport layer was formed of the following compound ETL_B, and the N-type charge generation layer was formed of the following compound NCGL_A, thereby manufacturing an organic electroluminescent device.

<Example 3>

In the same configuration as in Comparative Example 1, the first electron transport layer was formed of the compound ETL_C, and the N-type charge generation layer was formed of the compound NCGL_C, thereby manufacturing an organic electroluminescent device.

The materials of the first electron transport layer and the N-type charge generation layer or the configuration of the light emitting layer in the comparative examples and embodiments do not limit the content of the present invention.

The driving voltage and luminous efficiency of the organic light emitting diodes prepared according to Comparative Examples 1 to 4 and Examples 1 to 3 were measured, and are shown in Table 1 below. In addition, in Table 1 below, the result value of Comparative Example 1, in which the device was driven at a current density of 10 mA/cm 2 , was 100%, and the resulting values of Comparative Examples 2 to 4 and Examples 1 to 3 were expressed as a percentage.

Current density (10mA/cm2) Driving voltage (V) Luminous Efficiency (Cd/A) Comparative Example 1 100% 100% Comparative Example 2 97% 103% Comparative Example 3 98% 104% Comparative Example 4 102% 93% Example 1 86% 117% Example 2 88% 112% Example 3 90% 114%

In Comparative Example 1, the electron transport layer was composed of ETL_R1, and the N-type charge generation layer was composed of NCGL_R. ETL_R1 is a benzoimidazole-substituted anthracene compound, and NCGL_R is a phenanthroline compound (Bphen).

In Comparative Example 2, the electron transport layer was composed of ETL_A, and the N-type charge generation layer was composed of NCGL_R. ETL_A is a phenanthroline substituted anthracene compound.

In Comparative Example 3, the electron transport layer was composed of ETL_R1, and the N-type charge generation layer was composed of NCGL_B. NCGL_B is a carboline-substituted pyrene compound.

In Comparative Example 4, the electron transport layer was composed of ETL_R2, and the N-type charge generation layer was composed of NCGL_C. ETL_R2 is a pyridine-substituted fluorene compound, and NCGL_C is a carboline-substituted anthracene compound.

In Example 1, the electron transport layer was composed of ETL_A, and the N-type charge generation layer was composed of NCGL_B. ETL_A is a phenanthroline-substituted anthracene compound, and NCGL_B is a carboline-substituted pyrene compound.

In Example 2, the electron transport layer was composed of ETL_B, and the N-type charge generation layer was composed of NCGL_A. ETL_B is a phenanthroline-substituted anthracene compound, and NCGL_A is a carboline-substituted anthracene compound.

In Example 3, the electron transport layer was composed of ETL_C, and the N-type charge generation layer was composed of NCGL_C. ETL_C is a phenanthroline-substituted anthracene compound, and NCGL_C is a carboline-substituted anthracene compound.

Referring to Table 1, Example 1 includes a phenanthroline derivative in the electron transport layer and a carboline derivative in the N-type charge generation layer, so that only one of the electron transport layer and the N-type charge generation layer contains a phenanthroline derivative or It can be seen that the driving voltage was lowered by 12 to 16% and the luminous efficiency was increased by 13 to 24% compared to Comparative Examples 1 to 4 including the carboline derivative.

Example 2 includes a phenanthroline derivative in the electron transport layer and a carboline derivative in the N-type charge generation layer, thereby including a phenanthroline derivative or a carboline derivative in only one of the electron transport layer and the N-type charge generation layer. It can be seen that the driving voltage was lowered by 10 to 14% and the luminous efficiency was increased by 8 to 19% compared to Examples 1 to 4.

Example 3 includes a phenanthroline derivative in the electron transport layer and a carboline derivative in the N-type charge generating layer, thereby including a phenanthroline derivative or a carboline derivative in only one of the electron transport layer and the N-type charge generating layer. It can be seen that the driving voltage was lowered by 8 to 12% and the luminous efficiency was increased by 10 to 21% compared to Examples 1 to 4.

The present invention provides an electron transport layer from an N-type charge generating layer by using an anthracene or a pyrene compound including a carboline derivative in the N-type charge generating layer and including a phenanthroline derivative for at least one electron transport layer located in the light emitting part Alternatively, it facilitates the movement of electrons transferred to the light emitting layer.

In addition, the electron transport layer is composed of a phenanthroline compound and includes a phenanthroline ring containing nitrogen, thereby facilitating the transport of electrons to the light emitting layer. And since the triphenyl derivative is connected to the phenanthroline derivative, the electrons from the N-type charge generating layer to the light emitting layer are more easily moved.

In addition, by using a pyrene compound or anthracene compound containing a carboline derivative in the N-type charge generation layer, the nitrogen of sp2 hybrid orbital, which is relatively rich in electrons in the carboline derivative, is an alkali metal or A gap state is formed by combining with an alkaline earth metal, and electrons are smoothly transferred from the P-type charge generating layer to the N-type charge generating layer by the gap state.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the technical configuration of the present invention can be changed to other specific forms by those skilled in the art to which the present invention pertains without changing the technical spirit or essential features of the present invention. It will be appreciated that this may be practiced. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. In addition, the scope of the present invention is indicated by the claims to be described later rather than the above detailed description. In addition, all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention.

100: organic electroluminescent device 110: anode
120: first hole injection layer 130: first hole transport layer
140: blue light emitting layer 150: first electron transport layer
160: charge generation layer 160N: N-type charge generation layer
160P: P-type charge generation layer 170: second hole injection layer
180: second hole transport layer 190: yellow light emitting layer
200: second electron transport layer 210: electron injection layer
220: cathode

Claims (9)

a first light emitting unit positioned between the anode and the cathode and including a first light emitting layer and a first electron transport layer;
a second light emitting unit positioned on the first light emitting unit and including a second light emitting layer and a second electron transport layer; and
and a charge generation layer disposed between the first light emitting part and the second light emitting part, and including an N-type charge generation layer,
At least one of the first electron transport layer and the second electron transport layer consists of any one of the electron transport compounds represented by the following Chemical Formulas 1 to 8,
The N-type charge generating layer is an organic electroluminescent device, characterized in that consisting of any one of the charge generating compound represented by the following formulas 9 and 10.
[Formula 1]

[Formula 2]

[Formula 3]

[Formula 4]

In Formulas 1 to 4, R ₂₁ to R ₃₃ are each independently hydrogen, a substituted or unsubstituted aryl group having 6 to 60 carbon atoms, a substituted or unsubstituted heteroaryl group having 4 to 60 carbon atoms, or 1 to 10 carbon atoms An alkyl group, any one of an alkoxy group having 1 to 10 carbon atoms, R ₂₁ and R ₂₂ , R ₂₃ and R ₂₄ , R ₂₅ and R ₂₆ , R ₂₇ and R ₂₈ , R ₂₉ and R ₃₀ , and R ₃₁ and R ₃₂ At least one of them may be bonded to each other to form a ring, and X ₁₀ to X ₂₂ are each independently C or N,
[Formula 5]

[Formula 6]

[Formula 7]

[Formula 8]

In Formulas 5 to 8, R ₂₁ to R ₃₃ are each independently hydrogen, a substituted or unsubstituted aryl group having 6 to 60 carbon atoms, a substituted or unsubstituted heteroaryl group having 4 to 60 carbon atoms, or 1 to 10 carbon atoms An alkyl group, any one of an alkoxy group having 1 to 10 carbon atoms, R ₂₁ and R ₂₂ , R ₂₃ and R ₂₄ , R ₂₅ and R ₂₆ , R ₂₈ and R ₂₉ , R ₂₇ and R ₃₁ , R ₂₉ and R ₃₀ , At least one of R ₃₁ and R ₃₂ , R ₃₂ and R _{33 ,} and R ₃₀ and R ₃₃ may be bonded to each other to form a ring, and X ₁₀ to X ₂₂ are each independently C or N;
[Formula 9]

[Formula 10]

In Formulas 9 and 10, X ₁ to X ₉ are each independently C or N, and _{at least one of X 1} to X ₉ includes N, or at least one of X ₁ to X ₄ and X ₅ to X ₉ At least one includes N, and L is a single bond, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, or a substituted or unsubstituted hetero arylene group having 4 to 20 carbon atoms,
In Formula 9, R ₁ to R ₉ are each independently hydrogen, a substituted or unsubstituted C6 to C60 aryl group, a substituted or unsubstituted C6 to C60 heteroaryl group, a C1 to C10 alkyl group, Any one of an alkoxy group having 1 to 10 carbon atoms,
In Formula 10, R ₁₀ to R ₁₈ are each independently hydrogen, a substituted or unsubstituted aryl group having 6 to 60 carbon atoms, a substituted or unsubstituted heteroaryl group having 6 to 60 carbon atoms, an alkyl group having 1 to 10 carbon atoms, Any one of a C1-C10 alkoxy group. According to claim 1,
At least one of the first electron transport layer and the second electron transport layer is an organic electroluminescent device, characterized in that any one of the electron transport compound represented by the following Chemical Formulas 11 to 14.
[Formula 11]

[Formula 12]

[Formula 13]

[Formula 14]

In Formulas 11 to 14, R ₂₁ to R ₃₃ are each independently hydrogen, a substituted or unsubstituted aryl group having 6 to 60 carbon atoms, a substituted or unsubstituted heteroaryl group having 4 to 60 carbon atoms, and 1 to 10 carbon atoms An alkyl group, any one of an alkoxy group having 1 to 10 carbon atoms, R ₂₁ and R ₂₂ , R ₂₃ and R ₂₄ , R ₂₅ and R ₂₆ , R ₂₇ and R ₂₈ , R ₂₉ and R ₃₀ , and R ₃₁ and R ₃₂ At least one of them may be bonded to each other to form a ring.
According to claim 1,
At least one of the first electron transport layer and the second electron transport layer is an organic electroluminescent device, characterized in that any one of the electron transport compounds represented by the following Chemical Formulas 15 to 19.
[Formula 15]

[Formula 16]

[Formula 17]

[Formula 18]

In Formulas 15 to 18, R ₂₁ to R ₃₃ are each independently hydrogen, a substituted or unsubstituted aryl group having 6 to 60 carbon atoms, a substituted or unsubstituted heteroaryl group having 4 to 60 carbon atoms, and 1 to 10 carbon atoms An alkyl group, any one of an alkoxy group having 1 to 10 carbon atoms, R ₂₁ and R ₂₂ , R ₂₃ and R ₂₄ , R ₂₅ and R ₂₆ , R ₂₈ and R ₂₉ , R ₂₇ and R ₃₁ , R ₂₉ and R ₃₀ , At least one of R ₃₁ and R ₃₂ , R ₃₂ and R ₃₃ , and R ₃₀ and R ₃₃ may be bonded to each other to form a ring.
According to claim 1,
The electron transport compound is an organic electroluminescent device, characterized in that any one of the compounds shown below.

According to claim 1,
The N-type charge generating layer is an organic electroluminescent device, characterized in that consisting of any one of the charge generating compound represented by the following Chemical Formulas 19 and 20.
[Formula 19]

[Formula 20]

In Formulas 19 and 20, X ₁ to X ₉ are each independently C or N, and _{at least one of X 1} to X ₉ includes N, or at least one of X ₁ to X ₄ and X ₅ to X ₉ At least one includes N, and L is a single bond, a substituted or unsubstituted C6 to C20 arylene group or a substituted or unsubstituted C4 to C20 heteroarylene group,
In Formula 19, R ₁₉ is hydrogen, a substituted or unsubstituted aryl group having 6 to 60 carbon atoms, a substituted or unsubstituted heteroaryl group having 4 to 60 carbon atoms, an alkyl group having 1 to 10 carbon atoms, alkoxy having 1 to 10 carbon atoms is one of the groups,
In Formula 20, R ₂₀ is hydrogen, a substituted or unsubstituted aryl group having 6 to 60 carbon atoms, a substituted or unsubstituted heteroaryl group having 4 to 60 carbon atoms, an alkyl group having 1 to 10 carbon atoms, alkoxy having 1 to 10 carbon atoms one of the groups
6. The method of claim 5,
The charge generating compound is an organic electroluminescent device, characterized in that any one of the compounds shown below.

a first light emitting unit positioned between the anode and the cathode and including a first light emitting layer and a first electron transport layer;
a second light emitting unit positioned on the first light emitting unit and including a second light emitting layer and a second electron transport layer;
a third light emitting unit positioned on the second light emitting unit and including a third light emitting layer and a third electron transport layer;
a first charge generation layer positioned between the first light emitting unit and the second light emitting unit; and
a second charge generation layer positioned between the second light emitting unit and the third light emitting unit;
At least one of the first electron transport layer, the second electron transport layer and the third electron transport layer comprises the electron transport compound according to any one of claims 1 to 4,
At least one of the first charge generating layer and the second charge generating layer is an organic electroluminescent device comprising the charge generating compound according to any one of claims 1, 5 and 6.
8. The method of claim 7,
At least one of the first charge generation layer and the second charge generation layer includes an N-type charge generation layer and a P-type charge generation layer, and the N-type charge generation layer includes the charge generation compound. organic electroluminescent device.
at least two light emitting units positioned between the anode and the cathode, each light emitting layer including an electron transport layer;
charge generation layers positioned between the at least two light emitting units; and
At least one of the electron transport layers included in the light emitting units comprises the electron transport compound according to any one of claims 1 to 4,
At least one of the charge generating layers is an organic electroluminescent device comprising the charge generating compound according to any one of claims 1, 5 and 6.

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