WO2020256431A1 - Organic electroluminescent element - Google Patents

Abstract

The present invention relates to an organic electroluminescent element in which a light-emitting layer includes a plurality of hosts and dopants, wherein one of the plurality of hosts is applied as a material for a hole transport auxiliary layer in a hole transport region, thereby simultaneously exhibiting effects such as high luminous efficiency, low driving voltage, and a long lifespan.

Description

Organic electroluminescent device

The present invention relates to an organic electroluminescent device that simultaneously exhibits high luminous efficiency, low driving voltage, and long life.

In general, in an organic electroluminescent device (hereinafter referred to as'organic EL device'), when a current or voltage is applied to two electrodes, holes are injected into the organic material layer from the anode, and electrons are injected into the organic material layer from the cathode. do. When the injected holes and electrons meet, excitons are formed, and these excitons fall to the ground state to emit light.

These organic EL devices can be classified into a fluorescent EL device in which singlet excitons contribute to light emission and a phosphorescent EL device in which triplet excitons contribute to light emission according to the type of electron spin of the excitons.

Fluorescent EL devices may theoretically have an internal quantum efficiency of up to 25% depending on the generation rate, whereas a phosphorescent EL device may have an internal quantum efficiency of up to 100%. In the case of a phosphorescent EL device, the triplet and the singlet are involved in the internal quantum efficiency, so that high internal quantum efficiency can be obtained. On the other hand, a fluorescent EL device has a maximum internal quantum efficiency of a quarter of that of phosphorescence because only a singlet transition occurs. In this way, the phosphorescent EL device theoretically has higher luminous efficiency than the fluorescent EL device.

However, unlike green and red phosphorescent EL devices, blue phosphorescent EL devices are not commercially available due to low levels of development for a phosphorescent dopant having deep blue color purity and high efficiency, and a host having a wide energy gap. Accordingly, a blue fluorescent EL element is used instead of the blue phosphorescent EL.

However, according to the recent trend of increasing the size and resolution of the display, the development of an organic EL device having high efficiency and long life is required. In particular, the high resolution of the display can be implemented when more pixels are formed in the same area. For this reason, the light-emitting area of the organic EL element decreases, and further, the decrease in the light-emitting area serves as a cause of shortening the life of the organic EL element.

Therefore, various studies are being conducted to improve the characteristics of the organic EL device, but satisfactory results have not been obtained until now.

The present invention provides an organic electroluminescent device in which the emission layer includes a plurality of hosts and a dopant, but includes one of the plurality of hosts as a material for the hole transport auxiliary layer to exhibit effects such as low driving voltage, high luminous efficiency, and long lifespan. It aims to do.

In order to achieve the above object, the present invention is a positive electrode; A cathode disposed opposite to the anode; An organic material layer interposed between the anode and the cathode and including a hole transport region, a light emitting layer, and an electron transport region sequentially disposed on the anode, and the hole transport region is sequentially disposed on the anode A hole injection layer, a hole transport layer, and a hole transport auxiliary layer, wherein the emission layer includes a plurality of hosts and a dopant, and the plurality of hosts includes a first host; And a second host different from the first host and the same as the material of the hole transport auxiliary layer.

In the present invention, a light emitting layer including a plurality of hosts and a dopant is provided, and by applying one of the plurality of hosts as a material for a hole transport auxiliary layer, an organic electroluminescent device having low driving voltage, high luminous efficiency and long lifespan characteristics is provided. Can provide.

In addition, by applying the organic electroluminescent device of the present invention to a display panel, it is possible to provide a display panel with improved performance and lifetime.

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

2 is a cross-sectional view showing the structure of an organic electroluminescent device according to another embodiment of the present invention.

FIG. 2 is a graph showing the relationship of the highest occupied molecular orbital (HOMO) energy level between a hole transport layer, a hole transport auxiliary layer, and an emission layer according to an embodiment of the present invention.

3 is a graph showing a relationship between a lower unoccupied molecular orbital (LUMO) energy level between a hole transport auxiliary layer and a light emitting layer according to an embodiment of the present invention.

** Explanation of sign **

100: anode, 200: cathode,

300: organic material layer, 310: hole transport region,

311: hole injection layer, 312: hole transport layer,

313: hole transport auxiliary layer, 320: light emitting layer,

330: electron transport region, 331: electron transport layer,

332: electron injection layer, 333: electron transport auxiliary layer

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail together 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, only these embodiments make the disclosure of the present invention complete, and common knowledge in the technical field to which the present invention pertains. It is provided to completely inform the scope of the invention to those who have, and the invention is only defined by the scope of the claims. Accordingly, in some embodiments, well-known process steps, well-known device structures, and well-known techniques have not been described in detail in order to avoid obscuring interpretation of the present invention. The same reference numerals refer to the same components throughout the specification.

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used as meanings that can be commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not interpreted ideally or excessively unless explicitly defined specifically.

The organic electroluminescent device according to the present invention comprises: an anode; A negative electrode disposed opposite to the positive electrode; And one or more organic material layers interposed between the anode and the cathode and including a hole transport region, a light emitting layer, and an electron transport region, and one of a plurality of hosts in the light emitting layer is a hole transport auxiliary layer in the hole transport region. It is applied as a material of. Accordingly, the organic electroluminescent device of the present invention may have a low driving voltage, high luminous efficiency, and long life.

Specifically, in the organic electroluminescent device of the present invention, the emission layer includes a plurality of hosts, such as a first host and a second host that are different from each other, thereby improving the recombination efficiency of holes and electrons, and excitons transferred from the host to the dopant are It is possible to prevent the phenomenon of reversing back to the host.

In this case, the present invention forms a hole transport auxiliary layer between the hole transport layer and the light emitting layer by using the same material as any one of the plurality of hosts. Accordingly, the present invention not only lowers the hole injection barrier between the hole transport layer and the light emitting layer, but also exhibits a barrier-free effect between the light emitting layer and the hole transport auxiliary layer, so that holes injected from the hole transport layer are smoothly supplied to the light emitting layer through the hole transport auxiliary layer. Can be. Accordingly, in the organic electroluminescent device of the present invention, the luminous efficiency is improved, the driving voltage is decreased, and the lifespan characteristics can be significantly improved.

Hereinafter, preferred embodiments of the organic electroluminescent device according to the present invention will be described with reference to the accompanying drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below.

1 is a cross-sectional view schematically showing the structure of an organic light-emitting device according to an embodiment, and FIG. 2 is a cross-sectional view schematically showing the structure of an organic light-emitting device according to another embodiment.

1 and 2, the organic light-emitting device includes an anode 100, one or more organic material layers 300, and a cathode 200 in sequence, and the organic material layer 300 transports holes. A region 310, a light emitting layer 320, and an electron transport region 330 are included. Optionally, the organic light-emitting device may further include a capping layer (not shown) disposed on the second electrode 200.

Hereinafter, each configuration of the organic light emitting device according to the present invention will be described in detail.

(1) anode

The organic electroluminescent device of the present invention includes an anode 100. The anode 100 is disposed on a substrate and is electrically connected to a driving thin film transistor to receive a driving current from the driving thin film transistor. Since the anode 100 is formed of a material having a relatively high work function, holes are injected into the adjacent organic material layer, that is, the hole transport region 310 (eg, the hole injection layer 311).

The material forming such an anode is not particularly limited, and conventional materials known in the art may be used. Metals such as vanadium, chromium, copper, zinc, and gold; Alloys thereof; Metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); Combinations of metals and oxides such as ZnO:Al and SnO ₂ :Sb; Conductive polymers such as polythiophene, poly(3-methylthiophene), poly[3,4-(ethylene-1,2-dioxy)thiophene] (PEDT), polypyrrole, and polyaniline; And carbon black, but are not limited thereto.

The method of manufacturing the positive electrode is not particularly limited, and may be manufactured through a conventional method known in the art. For example, it may be formed by coating the anode material on a substrate through a known thin film forming method such as a sputtering method, an ion plating method, a vacuum deposition method, and a spin coating method.

The substrate is a plate-shaped member supporting the organic electroluminescent device, and includes, for example, a silicon wafer, quartz, glass plate, metal plate, plastic film and sheet, but is not limited thereto.

(2) cathode

In the organic electroluminescent device of the present invention, the cathode 200 is disposed opposite to the anode, and specifically disposed on the electron transport region 330. Since the cathode 200 is made of a material having a relatively low work function, electrons are injected into the adjacent organic material layer, that is, the electron transport region 330 (eg, the electron injection layer 332).

The material forming the negative electrode is not particularly limited, and a conventional material known in the art may be used. For example, metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver (Ag), tin, and lead; Alloys thereof; And multi-layered materials such as LiF/Al and LiO ₂ /Al, but are not limited thereto.

The method of manufacturing the negative electrode is not particularly limited, and like the positive electrode, it may be manufactured through a conventional method known in the art. For example, the cathode material may be formed by coating the cathode material on one or more organic material layers 300 below, specifically an electron transport region, for example, an electron injection layer 332 through the aforementioned thin film formation method.

(3) organic material layer

In the organic electroluminescent device of the present invention, one or more organic material layers 300 are disposed between the anode 100 and the cathode 200.

The organic material layer 300 includes a hole transport region 310, an emission layer 320 and an electron transport region 330.

According to an example, as shown in FIG. 1, one or more organic material layers 300 are a hole injection layer 311, a hole transport layer 312, and a hole transport auxiliary layer 313 sequentially disposed on the anode 100. , An emission layer 320, an electron transport layer 331, and an electron injection layer 332 may be included.

According to another example, as shown in FIG. 2, one or more organic material layers 300 may include a hole injection layer 311, a hole transport layer 312, and a hole transport auxiliary layer 313 sequentially disposed on the anode 100. ), a light emitting layer 320, an electron transport auxiliary layer 333, an electron transport layer 331, and an electron injection layer 332.

Hereinafter, each organic material layer will be described.

1) hole transport area

In the organic light emitting diode 100 of the present invention, the hole transport region 310 is a part of the organic material layer 300 disposed on the anode 100, and holes injected from the anode 100 are adjacent to another organic layer, specifically It serves to move to the light emitting layer 320. The hole transport region 310 includes a hole injection layer 311, a hole transport layer 312, and a hole transport auxiliary layer 313 sequentially stacked on the anode 100.

The material constituting the hole injection layer 311 and the hole transport layer 312 of the present invention is not particularly limited as long as it is a material having a low hole injection barrier and high hole mobility, and the hole injection layer/transport layer material used in the art is used. Can be used without restrictions. In this case, the material forming the hole injection layer 311 and the hole transport layer 312 may be the same or different from each other.

Specifically, the hole injection layer 311 includes a hole injection material known in the art. Non-limiting examples of the hole injection material include phthalocyanine compounds such as copper phthalocyanine; DNTPD (N,N'-diphenyl-N,N'-bis-[4-(phenyl-m-tolyl-amino)-phenyl]-biphenyl-4,4'-diamine), m-MTDATA(4,4' ,4"-tris(3-methylphenylphenylamino) triphenylamine), TDATA(4,4'4"-Tris(N,N-diphenylamino)triphenylamine), 2TNATA(4,4',4"-tris(N,-(2 -naphthyl)-N-phenylamino}-triphenylamine), PEDOT/PSS(Poly(3,4-ethylenedioxythiophene)/Poly(4-styrenesulfonate)), PANI/DBSA(Polyaniline/Dodecylbenzenesulfonic acid), PANI/CSA(Polyaniline/Camphor) sulfonicacid), PANI/PSS((Polyaniline)/Poly(4-styrenesulfonate)), and the like, and these may be used alone or in combination of two or more.

The hole transport layer 312 includes a hole transport material known in the art. Non-limiting examples of the hole transport material include carbazole derivatives such as N-phenylcarbazole and polyvinylcarbazole; Fluorene derivatives; Amine derivatives; TPD(N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1-biphenyl]-4,4'-diamine), TCTA(4,4',4"-tris(N Triphenylamine derivatives such as -carbazolyl)triphenylamine); NPB(N,N'-di(1-naphthyl)-N,N'-diphenylbenzidine), TAPC(4,4'-Cyclohexylidene bis[N,N-bis (4-methylphenyl)benzenamine]), and the like, and these may be used alone or in combination of two or more.

In addition, the hole transport auxiliary layer 313 can prevent the electrons injected into the light emitting layer 320 from moving to the hole transport layer 312 while easily moving holes from the hole transport layer 312 to the light emitting layer 320 . The material forming the hole transport auxiliary layer 313 is not particularly limited as long as it has a low hole injection barrier and a high hole mobility, and materials known in the art may be used without limitation.

However, in the present invention, in order to exhibit a barrier-free effect between the light emitting layer and the hole transport auxiliary layer, one of the plurality of hosts in the light emitting layer, in particular, a material having a low hole injection barrier and high hole mobility, is included as a material of the hole transport auxiliary layer. do. Accordingly, in the organic electroluminescent device of the present invention, holes injected from the hole transport layer are smoothly supplied to the light emitting layer through the hole transport auxiliary layer, thereby increasing the binding rate between holes and electrons, thereby significantly increasing the number of excitons. have. For this reason, in the present invention, high-efficiency light emission characteristics can be exhibited, and while driving voltage is lowered, life characteristics can be significantly improved.

In particular, in order to exhibit a barrier-free effect between the hole transport auxiliary layer 313 and the light emitting layer 320, as well as to lower the hole injection barrier between the hole transport auxiliary layer 313 and the hole transport layer 312, the hole transport auxiliary layer The material of 313 needs to be selected in consideration of physical properties such as differences in HOMO energy levels or differences in LUMO energy levels between the hole transport auxiliary layer 313 and the hole transport layer 312 and the light emitting layer 320.

According to an example, the material of the hole transport auxiliary layer is selected so that the hole transport auxiliary layer 313 of the present invention satisfies the following relational expression 1 (see FIG. 3).

[Relationship 1]

(In the above formula,

HOMO _HTL is the HOMO energy level of the hole transport layer,

HOMO _aHTL is the HOMO energy level of the hole transport auxiliary layer,

HOMO _EL is the HOMO energy level of the light emitting layer).

Specifically, a difference between the HOMO energy level of the hole transport auxiliary layer 313 and the HOMO energy level of the hole transport layer 312 may be in the range of more than about 0 eV to less than 1.0 eV. In addition, a difference between the HOMO energy level of the hole transport auxiliary layer 313 and the HOMO energy level of the light emitting layer 320 may be in the range of more than about 0 eV to less than 1.0 eV.

In this way, when the HOMO energy level of the hole transport auxiliary layer 313 is between the HOMO energy level of the hole transport layer 312 and the HOMO energy level of the light emitting layer 320, the HOMO energy level has a stepwise arrangement, and the anode Holes injected from may be smoothly injected from the hole transport layer to the light emitting layer.

According to another example, the material of the hole transport auxiliary layer is selected so that the hole transport auxiliary layer 313 of the present invention satisfies the following relational expression 2 (see FIG. 4).

[Relationship 2]

(In the above formula,

LUMO _aHTL is the LUMO energy level of the hole transport auxiliary layer,

LUMO _EL is the LUMO energy level of the light emitting layer).

Specifically, a difference between the LUMO energy level of the hole transport auxiliary layer and the LUMO energy level of the emission layer may be in the range of more than 0 eV to less than 1.0 eV.

In this way, when the absolute value of the LUMO energy level of the hole transport auxiliary layer 313 is less than the absolute value of the LUMO energy level of the light emitting layer 320, electrons present in the light emitting layer are blocked by the energy barrier of the hole transport auxiliary layer and transport holes. It is prevented from moving to the auxiliary layer, and thus binding of electrons and holes in the light emitting layer can be increased.

According to another example, the hole transport auxiliary layer 313 of the present invention may have a triplet energy (T1) in the range of about 2.0 eV or more, specifically about 2.0 to 3.0 eV. In this case, excitons formed in the light emitting layer are prevented from moving to the hole transport auxiliary layer, thereby contributing to improvement of the lifespan and efficiency of the device.

Any material having physical properties such as the aforementioned HOMO energy level and LUMO energy level may be used as the hole transport auxiliary layer material of the present invention.

According to an example, the material of the auxiliary hole transport layer 313 of the present invention may be a compound represented by Formula 1 below.

In Formula 1,

Y ₁ and Y ₂ are the same as or different from each other, each independently a single bond, or is selected from the group consisting of NR ₃ , O, S, and CR ₄ R ₅ , provided that both Y ₁ and Y ₂ are single bonds Is excluded,

In this case, when NR ₃ is plural, the plurality of NR ₃ is the same or different from each other, and when CR ₄ R ₅ is plural, the plurality of CR ₄ R ₅ are the same or different from each other;

m and n are each independently an integer of 0 to 4;

R ₁ to R ₅ are the same as or different from each other, and each independently hydrogen, deuterium, halogen group, cyano group, nitro group, amino group, C ₁ to C ₄₀ alkyl group, C ₂ to C ₄₀ alkenyl group, C ₂ ~ C ₄₀ alkynyl group, C ₃ ~ C ₄₀ cycloalkyl group, 3 to 40 nuclear atoms heterocycloalkyl group, C ₆ ~ C ₆₀ aryl group, 5 to 60 nuclear atoms heteroaryl group, C ₁ ~ C ₄₀ alkyloxy group, C ₆ ~ C ₆₀ aryloxy group, C ₁ ~ C ₄₀ alkylsilyl group, C ₆ ~ C ₆₀ arylsilyl group, C ₁ ~ C ₄₀ alkyl boron group, C ₆ ~ aryl of C ₆₀ boron group, C ₆ ~ C ₆₀ aryl phosphine group, C ₆ ~ C aryl phosphine oxide ₆₀ group and a C ₆ ~, or selected from the group consisting of an aryl amine of the C _60, or adjacent groups bonded to the condensation of Can form a ring;

The alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group, aryloxy group, alkyloxy group, cycloalkyl group, heterocycloalkyl group, arylamine group, alkylsilyl group, alkyl boron group, aryl of the R ₁ to R ₅ A boron group, a phosphine group, a phosphine oxide group, and an arylamine group are each independently hydrogen, deuterium (D), halogen, cyano group, nitro group, C ₁ to C ₄₀ alkyl group, C ₂ to C ₄₀ alkenyl group , C ₂ to C ₄₀ alkynyl group, C ₃ to C ₄₀ cycloalkyl group, heterocycloalkyl group having 3 to 40 nuclear atoms, C ₆ to C ₆₀ aryl group, heteroaryl group having 5 to 60 nuclear atoms, C ₁ ~ C ₄₀ alkyloxy group, C ₆ ~ C ₆₀ aryloxy group, C ₁ ~ C ₄₀ alkylsilyl group, C ₆ ~ C ₆₀ arylsilyl group, C ₁ ~ C ₄₀ alkyl boron group, arylboronic group of _{C 6 ~ C 60, C 6} ~ C 60 of the aryl phosphine group, C ₆ ~ C ₆₀ aryl phosphine oxide group and one substituent at least one selected from the group consisting of an aryl amine of the C ₆ ~ C ₆₀ of Substituted or unsubstituted, in this case, when the substituents are plural, they may be the same or different from each other.

The compound represented by Formula 1 has a carbazole-based moiety or an oxanthrene-based moiety having a large electron donating group (EDG) property, or Or, it includes a dibenzo-based moiety (eg, dibenzofuran-based moiety, dibenzothiophene-based moiety, etc.) having excellent carrier transport ability due to excellent amphoteric properties of electrons and holes. Various kinds of substituents are introduced on one or both sides of the moiety. Depending on the characteristics of these substituents, the compound of Formula 1 may have various characteristics. For example, when the substituent is an electron donor (EDG) known in the art, the compound of Formula 1 may have excellent hole characteristics. When the compound of Formula 1 is applied simultaneously as a material of the hole transport auxiliary layer and a host of the light emitting layer, holes injected from the anode can be smoothly transferred from the hole transport layer to the light emitting layer, thereby lowering the driving voltage of the organic electroluminescent device, It can induce high efficiency and long life.

In addition, since the molecular weight of the compound of the compound represented by Formula 1 is significantly increased by controlling the types and locations of various substituents introduced into the moiety described above, the glass transition temperature is high, thus improving the thermal stability of the organic electroluminescent device. It not only improves, but also has an effect of inhibiting crystallization of the organic material layer, and thus durability and life characteristics of the device can be greatly improved.

The compound represented by Formula 1 may have various structures according to Y ₁ and Y ₂ . For example, the compound represented by Formula 1 may be a compound represented by any one of Formulas 2 to 15 below, but is not limited thereto.

In Formulas 2 to 15,

R ₁ to R ₅ , m, and n are each as defined in Formula 1.

In addition, in Formula 1, m and n are each independently an integer of 0 to 4, and specifically may be an integer of 0 to 2, respectively.

Here, when m and n are each 0, it means that hydrogen is not substituted with R ₁ and R ₂ , respectively, and when m and n are each an integer of 1 to 4, at least one R ₁ and at least one R ₂ are each The same or different, each independently a substituent excluding hydrogen, specifically as defined in Formula 1 (however, excluding hydrogen), more specifically deuterium, halogen group, cyano group, nitro group, amino group, C ₁ ~ C ₄₀ alkyl group, C ₆ ~ C ₆₀ aryl group, a heteroaryl group having 5 to 60 nuclear atoms and a C ₆ ~ C ₆₀ arylamine group selected from the group consisting of, or adjacent groups (eg, other R ₁ or R ₂ ) may form a condensed aromatic ring of C ₅ to C ₆₀ or a condensed heteroaromatic ring of 5 to 60 members by bonding with R ₂ ). Here, the heterocycloalkyl group, heteroaryl group, and condensed heteroaromatic ring each contain at least one hetero atom selected from the group consisting of N, S, O, and Se.

In addition, specifically R ₃ to R ₅ are the same as or different from each other, and each independently hydrogen, a C ₁ to C ₄₀ alkyl group, a C ₆ to C ₆₀ aryl group, a heteroaryl group having 5 to 60 nuclear atoms, and Selected from the group consisting of C ₆ ~ C ₆₀ arylamine groups, or adjacent groups (eg, R ₄ and R ₅ ) are bonded to each other to form a C ₅ ~ C ₆₀ fused aromatic ring or a 5 to 60 membered condensed heteroaromatic Can form a ring. Here, the heterocycloalkyl group, heteroaryl group, and condensed heteroaromatic ring each contain at least one hetero atom selected from the group consisting of N, S, O, and Se.

According to these m, n, and R ₁ to R ₅ , the compound represented by Formula 1 may be a compound represented by any one of Formulas 16 to 41 below, but is not limited thereto.

In Formulas 16 to 41,

R ₁ to R ₅ are each the same as defined in Formula 1,

a is an integer of 0 to 4, specifically a is 0 or 1,

R ₆ to R ₉ are the same as or different from each other, and each independently hydrogen, deuterium, halogen group, cyano group, nitro group, amino group, C ₁ to C ₄₀ alkyl group, C ₂ to C ₄₀ alkenyl group, C ₂ to C ₄₀ alkynyl group, C ₃ to C ₄₀ cycloalkyl group, 3 to 40 nuclear atom heterocycloalkyl group, C ₆ to C ₆₀ aryl group, 5 to 60 nuclear atom heteroaryl group, C ₁ to C ₄₀ alkyloxy group, C ₆ ~ C ₆₀ aryloxy group, C ₁ ~ C ₄₀ alkylsilyl group, C ₆ ~ C ₆₀ arylsilyl group, C ₁ ~ C ₄₀ alkyl boron group, C ₆ ~ C group of ₆₀ arylboronic, C ₆ ~ C ₆₀ aryl phosphine group, C ₆ ~ C ₆₀ aryl phosphine is selected from the pin oxide groups and the group consisting of C ₆ ~ with an aryl amine of the C ₆₀ of, specifically, hydrogen, deuterium, halogen The group consisting of a group, a cyano group, a nitro group, an amino group, a C ₁ to C ₄₀ alkyl group, a C ₆ to C ₆₀ aryl group, a heteroaryl group having 5 to 60 nuclear atoms, and a C ₆ to C ₆₀ arylamine group Can be chosen from

In addition, in the compound represented by Formula 1, at least one of R ₁ to R ₅ may be a substituent represented by any one selected from the group consisting of the following structural formulas S1 to S5. At this time, the substituents of the structural formulas S1 to S4 are electron donor groups (EDG) having electron donation, and when introduced into at least one of R ₁ to R ₅ , the compound of Formula 1 may have excellent hole characteristics.

In the above structural formulas S1 to S5,

* Refers to a portion in which a bond with Formula 1 is formed;

L ₁ is a single bond, or is selected from the group consisting of a C ₆ to C ₃₀ arylene group and a heteroarylene group having 5 to 30 nuclear atoms, and may be specifically a single bond, a phenylene group, or a biphenylene group;

X ₁ is selected from the group consisting of NAr ₃ , O and S;

Ar ₁ to Ar ₃ are the same or different from each other, each independently selected from the group consisting of hydrogen, a C ₁ to C ₄₀ alkyl group, a C ₆ to C ₆₀ aryl group, and a heteroaryl group having 5 to 60 nuclear atoms, , Specifically, it may be selected from the group consisting of a phenyl group, a biphenyl group, a monovalent dimethylfluorene group, a monovalent dibenzofuran group, a monovalent dibenzothiophene group, and a monovalent carbazole group;

b and c are each 0 or 1;

The alkyl group, aryl group and heteroaryl group of Ar ₁ to Ar ₃ are each independently hydrogen, deuterium (D), halogen, cyano group, nitro group, C ₁ to C ₄₀ alkyl group, C ₂ to C ₄₀ alkenyl group, C ₂ to C ₄₀ alkynyl group, C ₃ to C ₄₀ cycloalkyl group, heterocycloalkyl group having 3 to 40 nuclear atoms, C ₆ to C ₆₀ aryl group, heteroaryl group having 5 to 60 nuclear atoms, C ₁ to C ₄₀ alkyloxy group, C ₆ to C ₆₀ aryloxy group, C ₁ to C ₄₀ alkylsilyl group, C ₆ to C ₆₀ arylsilyl group, C ₁ to C ₄₀ alkyl boron group, C group _{of 6} to arylboronic of C _60, C ₆ to C ₆₀ aryl phosphine group, substituted with one substituent at least one selected from the group consisting of an aryl amine of the C ₆ to C ₆₀ aryl phosphine oxide group, and a C ₆ to C ₆₀ of Or unsubstituted, and in this case, when the substituents are plural, they may be the same as or different from each other.

In addition, although not specifically shown in the structural formulas S1 to S5, at least one or more substituents R ₇ known in the art may be substituted. Specifically, R ₇ is the same as described in the definition section of R ₁ to R ₅ .

The compound represented by the above formula 1 may be embodied as the following compounds 1 to 20, but is not limited thereto.

The hole transport region 310 may be manufactured through a conventional method known in the art. For example, there are vacuum evaporation method, spin coating method, cast method, LB method (Langmuir-Blodgett), inkjet printing method, laser printing method, laser thermal imaging method (Laser Induced Thermal Imaging, LITI), and the like, but is not limited thereto.

2) light emitting layer

In the organic electroluminescent device of the present invention, the emission layer 320 is a part of the organic material layer 300 interposed between the anode 100 and the cathode 200, and specifically, a hole transport auxiliary layer of the hole transport region 310 It is placed on 313. The emission layer 320 is a layer in which holes and electrons injected from the anode and the cathode are combined to form excitons, and the color of light emitted by the organic electroluminescent device may vary depending on the material forming the emission layer 320. have.

The light emitting layer 320 of the present invention includes a plurality of hosts and dopants. At this time, any one of the plurality of hosts is the same as the material for forming the aforementioned hole transport auxiliary layer (hereinafter, “hole transport auxiliary layer material”).

According to an example, the plurality of hosts may include: a first host identical to the material of the auxiliary hole transport layer; And a second host different from the first host. As described above, when one of the plurality of hosts is the same as the material of the hole transport auxiliary layer, the barrier-free effect between the light emitting layer and the hole transport auxiliary layer is exerted, so that low driving voltage, high luminous efficiency, and long life characteristics of the device can be realized. .

The first host of the present invention is the same material as that of the hole transport auxiliary layer. Specifically, the first host may be a compound represented by Formula 1, more specifically, may be a compound represented by any one of Formulas 2 to 15, and more specifically represented by any one of Formulas 16 to 41. It can be a compound. According to an example, the first host of the present invention may be one of Compounds 1 to 20.

In addition, the second host is a host different from the first host, and is not particularly limited as long as it is known in the art, and non-limiting examples thereof include an alkali metal complex; Alkaline earth metal complexes; Or condensed aromatic ring derivatives. Specifically, examples of the second host include aluminum complexes, beryllium complexes, iridium compounds, anthracene derivatives, pyrene derivatives, triphenylene derivatives, carbazole derivatives, and dibenzofuran that can increase the luminous efficiency and lifespan of an organic electroluminescent device. It may be a derivative, a dibenzothiophene derivative, a fluorene derivative, a nitrogen-containing heterocyclic derivative, or a combination of one or more thereof.

However, in the present invention, in order to significantly increase the number of excitons in the emission layer and to prevent the reverse transition of excitons, when selecting the second host, physical properties such as the difference in HOMO energy level or difference in LUMO energy level with the first host You need to consider the difference.

According to an example, the second host may be a material satisfying the following relations 3 and 4.

[Relationship 3]

[Relationship 4]

In the above formula,

LUMO _host-1 is the LUMO energy level of the first host,

LUMO _host-2 is the LUMO energy level of the second host,

HOMO _host-1 is the HOMO energy level of the first host,

HOMO _host-2 is the HOMO energy level of the second host.

The ratio of use of the first host and the second host is not particularly limited, and may be, for example, a weight ratio of 30:70 to 90:10. If the ratio of use of the first host and the second host is the above-described ratio, the barrier-free effect between the light emitting layer and the hole transport auxiliary layer is further increased, and the inversion of exciton from the dopant to the host is more efficiently prevented. can do.

Optionally, the light emitting layer of the present invention may further include one or more other hosts (eg, a third host) different from the first host and the second host described above. In this case, since the example of the third host is the same as the example of the second host, it is omitted.

In the light emitting layer of the present invention, the dopant is not particularly limited as long as it is commonly known in the art. Such dopants may be classified into fluorescent dopants and phosphorescent dopants. The phosphorescent dopant may be an organometallic complex including Ir, Pt, Os, Re, Ti, Zr, Hf, or a combination of two or more thereof, but is limited thereto. no.

Meanwhile, the dopant may be classified into a red dopant, a green dopant, and a blue dopant, and red dopants, green dopants, and blue dopants commonly known in the art may be used without particular limitation.

Specifically, non-limiting examples of the red dopant include PtOEP (Pt(II) octaethylporphine: Pt(II) octaethylporphine), Ir(piq) ₃ (tris(2-phenylisoquinoline)iridium: tris(2-phenyliso). Quinoline) iridium), Btp ₂ Ir(acac) (bis(2-(2'-benzothienyl)-pyridinato-N,C3')iridium(acetylacetonate): bis(2-(2'-benzothienyl)-pyridina To-N, C3') iridium (acetylacetonate)), and the like, which may be used alone or in combination of two or more.

In addition, non-limiting examples of the green dopant include Ir (ppy) ₃ (tris (2-phenylpyridine) iridium: tris (2-phenylpyridine) iridium), Ir (ppy) ₂ (acac) (Bis (2-phenylpyridine) (Acetylacetonato)iridium(III): bis(2-phenylpyridine)(acetylaceto) iridium(III)), Ir(mppy) ₃ (tris(2-(4-tolyl)phenylpiridine)iridium: tris(2-(4) -Tolyl)phenylpyridine) iridium), C545T (10-(2-benzothiazolyl)-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H,11H-[1]benzopyrano [ 6,7,8-ij]-quinolizin-11-one: 10-(2-benzothiazolyl)-1,1,7,7-tetramethyl-2,3,6,7,-tetrahydro-1H, 5H,11H-[1]benzopyrano [6,7,8-ij]-quinolizin-11-one) and the like, which may be used alone or in combination of two or more.

In addition, non-limiting examples of the blue dopant include F ₂ Irpic (Bis[3,5-difluoro-2-(2-pyridyl)phenyl](picolinato)iridium(III): bis[3,5-difluoro- 2-(2-pyridyl)phenyl(picolinato) iridium(III)), (F ₂ ppy) ₂ Ir(tmd), Ir(dfppz) ₃ , DPVBi (4,4'-bis(2,2' -diphenylethen-1-yl)biphenyl: 4,4'-bis(2,2'-diphenylethen-1-yl)biphenyl), DPAVBi (4,4'-Bis[4-(diphenylamino)styryl] biphenyl: 4,4'-bis(4-diphenylaminostyryl)biphenyl), TBPe (2,5,8,11-tetra-tert-butyl perylene: 2,5,8,11-tetra-tert- Butyl perylene) and the like, which may be used alone or in combination of two or more.

The content of such a dopant is not particularly limited, and may be appropriately adjusted within a range known in the art.

For example, a plurality of hosts and dopants may be included in a weight ratio of 70:30 to 99.9:0.1 based on the total amount of the emission layer. Specifically, when the emission layer 320 is blue fluorescence, green fluorescence, or red fluorescence, a plurality of hosts and dopants may be included in a weight ratio of 80:20 to 99.9:0.1. Further, when the emission layer 320 is blue fluorescence, green fluorescence, or red phosphorescence, a plurality of hosts and dopants may be included in a weight ratio of 70:30 to 99:1.

As another example, the content of the dopant may range from about 0.1 to 30 parts by weight based on 100 parts by weight of the total amount of the first host and the second host.

The above-described light emitting layer 320 may be a single layer, or may be formed of a plurality of layers of two or more layers. Here, when the emission layer 320 is a plurality of layers, the organic electroluminescent device may emit light of various colors. Specifically, the present invention can provide an organic electroluminescent device having a mixed color by providing in series a plurality of light-emitting layers made of different materials. In addition, when a plurality of emission layers are included, the driving voltage of the device is increased, while the current value in the organic electroluminescent device is constant, thereby providing an organic EL device having improved luminous efficiency by the number of emission layers.

The light emitting layer 320 may be manufactured through a conventional method known in the art. For example, there are vacuum evaporation method, spin coating method, cast method, LB method (Langmuir-Blodgett), inkjet printing method, laser printing method, laser thermal imaging method (Laser Induced Thermal Imaging, LITI), and the like, but is not limited thereto.

3) electron transport area

In the organic electroluminescent device according to the present invention, the electron transport region 330 is an organic material layer disposed on the emission layer 320 and moves electrons injected from the cathode 200 to the emission layer 320.

The electron transport region 330 may include at least one selected from the group consisting of an electron transport auxiliary layer 333, an electron transport layer 331, and an electron injection layer 331. In this case, when considering the characteristics of the organic electroluminescent device, the electron transport region 330 includes the electron transport layer 331 and the electron injection layer 332 described above, as illustrated in FIG. 1, or illustrated in FIG. 2. As described above, it is preferable to include all of the electron transport auxiliary layer 333, the electron transport layer 331, and the electron injection layer 332.

In the electron transport region 330 according to the present invention, the electron injection layer 331 may use an electron injection material having easy electron injection and high electron mobility without limitation. Non-limiting examples of the electron injection material that can be used include the above bipolar compounds, anthracene derivatives, heteroaromatic compounds, and alkali metal complex compounds. Specifically, LiF, Li ₂ O, BaO, NaCl, CsF; Lanthanum group metals such as Yb and the like; Alternatively, there are metal halides such as RbCl and RbI, and these may be used alone or in combination of two or more.

The electron transport region 330 according to the present invention, specifically, the electron transport layer 331 and/or the electron injection layer 332 may be co-deposited with an n-type dopant to facilitate injection of electrons from the cathode. At this time, as the n-type dopant, an alkali metal complex compound known in the art may be used without limitation, and examples thereof include an alkali metal, an alkaline earth metal, or a rare earth metal.

In addition. The electron transport auxiliary layer 333 may prevent excitons or holes generated in the emission layer 320 from diffusing into the electron transport region. The electron transport auxiliary layer 333 may be formed of a material having conventional electron transport characteristics known in the art without limitation. For example, oxadiazole derivatives, triazole derivatives, phenanthroline derivatives (eg, BCP), heterocyclic derivatives containing nitrogen, and the like may be included.

The electron transport region 330 may be manufactured through a conventional method known in the art. For example, there are vacuum evaporation method, spin coating method, cast method, LB method (Langmuir-Blodgett), inkjet printing method, laser printing method, laser thermal imaging method (Laser Induced Thermal Imaging, LITI), and the like, but is not limited thereto.

4) Light-emitting auxiliary layer

Optionally, the organic electroluminescent device 100 of the present invention may further include a light emission auxiliary layer (not shown) disposed between the hole transport region 310 and the emission layer 320.

The light emission auxiliary layer serves to control the thickness of the organic material layer 300 while transporting holes moved from the hole transport region 310 to the emission layer 320 or blocking movement of electrons and/or excitons. In particular, the light-emitting auxiliary layer has a high LUMO value to prevent electrons from moving to the hole transport layer 312, and has a high triplet energy to prevent excitons of the light-emitting layer 320 from diffusing to the hole transport layer 312.

This light emission auxiliary layer may include a hole transport material, and may be made of the same material as the hole transport region. Further, the auxiliary light emitting layers of the red, green, and blue organic light emitting devices may be made of the same material.

The material for the light-emitting auxiliary layer is not particularly limited, and examples thereof include carbazole derivatives and arylamine derivatives. Specifically, examples of the light emitting auxiliary layer include NPD (N, N-dinaphthyl-N, N'-diphenyl benzidine), TPD (N, N'-bis-(3-methylphenyl)-N, N'-bis(phenyl) -benzidine), s-TAD, MTDATA(4, 4', 4″-Tris(N-3-methylphenyl-Nphenyl-amino)-triphenylamine), and the like, but are not limited thereto. These may be used alone or in combination of two or more.

In addition, the light emitting auxiliary layer may further include a p-type dopant in addition to the above-described material. As the p-type dopant usable in the present invention, any known p-type dopant generally used in the art may be used without particular limitation. At this time, the content of the P-type dopant may be appropriately adjusted within a range known in the art, and may be, for example, about 0.5 to 50 parts by weight based on 100 parts by weight of the hole transport material.

As known in the art, the light emission auxiliary layer is a vacuum deposition method, a spin coating method, a cast method, an LB method (Langmuir-Blodgett), an inkjet printing method, a laser printing method, and a laser induced thermal imaging method (LITI). It may be formed by, but is not limited thereto.

(4) capping layer

Optionally, the organic electroluminescent device 100 of the present invention may further include a capping layer (not shown) disposed on the above-described cathode 200.

The capping layer serves to protect the organic electroluminescent device and help light generated from the organic material layer to be efficiently emitted to the outside.

The capping layer is tris-8-hydroxyquinoline aluminum (Alq ₃ ), ZnSe, 2,5-bis(6′- (2′,2″-bipyridyl))-1,1-dimethyl-3,4-diphenylsilole , 4′-bis[N-(1-napthyl)-N-phenyl-amion] biphenyl (α-NPD), N,N′-diphenyl-N,N′-bis(3-methylphenyl) -1,1′ -biphenyl-4,4'-diamine (TPD), 1,1'-bis (di-4-tolylaminophenyl) cyclohexane (TAPC) may contain at least one selected from the group consisting of. The material forming such a capping layer is inexpensive compared to materials of other layers of the organic electroluminescent device.

Such a capping layer may be a single layer, but may include two or more layers having different refractive indices, so that the refractive index gradually changes while passing through the two or more layers.

The capping layer may be manufactured by a conventional method known in the art, and for example, various methods such as a vacuum deposition method, a spin coating method, a cast method, or a Langmuir-Blodgett (LB) method may be used.

The organic electroluminescent device according to the present invention has a structure in which an anode 100, an organic material layer 300, and a cathode 200 are sequentially stacked. In some cases, an insulating layer (not shown) or an adhesive layer (not shown) may be further included between the anode 100 and the organic material layer 300 or between the cathode 200 and the organic material layer 300. The organic electroluminescent device according to the present invention may have excellent lifespan characteristics because the life time of initial brightness increases while maintaining maximum luminous efficiency when voltage and current are applied.

The organic electroluminescent device of the present invention described above may be manufactured according to a conventional method known in the art. For example, after vacuum depositing an anode material on a substrate, an organic light-emitting device may be manufactured by vacuum-depositing a material of a hole transport area material, a light emitting layer material, an electron transport area material, and a cathode material on the anode in order. .

Hereinafter, the present invention will be described in detail through examples, but the following examples are only illustrative of the present invention, and the present invention is not limited by the following examples.

[Preparation Examples 1 to 20] HOMO, LUMO and triplet energy measurement of compounds 1 to 20

The following compounds 1 to 20 were prepared as the first host and hole transport auxiliary layer material of the present invention, and their HOMO, LUMO, and triplet energies were measured by methods known in the art, respectively, and are shown in Table 1 below. At this time, as controls, ADN, NPB and compound B were used. For reference, compound B is as described in Comparative Example 2.

1)HOMO energy level

The HOMO energy level of each compound was measured by CV (cyclic voltammetry) method.

2) LUMO energy level

After obtaining the bandgap energy of each compound by UV spectrum, the LUMO energy level was calculated as the difference between the bandgap energy and the HOMO energy level.

3) triplet energy

Each compound was prepared by dissolving it in 2-Methyltetrahydrofuran (2-methylTHF) solvent at a concentration of 10 ^-4 M, and then the phosphorescence spectrum was measured with a QuantaMaster 30 Spectrofluorometer (PTI) at 77K low temperature using liquid nitrogen.

	HOMO energy (eV)	LUMO energy (eV)	Triplet energy (eV)
Compound 1	5.44	2.28	2.6
Compound 2	5.47	2.26	2.7
Compound 3	5.29	2.22	2.6
Compound 4	5.39	2.26	2.8
Compound 5	5.32	2.03	2.5
Compound 6	5.65	2.17	2.7
Compound 7	5.69	2.18	2.6
Compound 8	5.58	2.14	2.7
Compound 9	5.75	2.25	2.5
Compound 10	5.59	2.24	2.7
Compound 11	5.58	2.15	2.7
Compound 12	5.73	2.27	2.6
Compound 13	5.61	2.18	2.6
Compound 14	5.66	2.22	2.7
Compound 15	5.56	2.17	2.6
Compound 16	5.52	2.26	2.5
Compound 17	5.38	2.25	2.4
Compound 18	5.49	2.21	2.2
Compound 19	5.51	2.19	2.3
Compound 20	5.43	2.24	2.4
ADN	5.80	2.62	1.73
NPB	5.03	1.45	2.5
Compound B	5.79	2.61	1.72

[Example 1]-Fabrication of blue organic electroluminescent device

After compound 1 prepared in Preparation Example 1 was subjected to high-purity sublimation purification by a conventionally known method, a blue organic electroluminescent device was manufactured according to the following procedure. First, ITO (Indium tin oxide) was coated with a thin film to a thickness of 1500 Å. The glass substrate was washed with distilled water and ultrasonic waves. After washing with distilled water, ultrasonically clean with a solvent such as isopropyl alcohol, acetone, methanol, etc., dry, transfer to a UV OZONE cleaner (Power Sonic 405, Hwashin Tech), and clean the substrate for 5 minutes using UV And transferred the substrate to a vacuum evaporator.

On the ITO transparent electrode prepared as described above, a hole injection layer, a hole transport layer, a hole transport auxiliary layer, a light emitting layer, an electron transport layer, an electron injection layer, and a cathode were sequentially stacked to manufacture an organic electroluminescent device. The structure of the manufactured device is shown in Table 2 below.

	compound	Thickness (nm)
Hole injection layer	DS-205 (Doosan Electronics)	80
Hole transport layer	NPB	15
Hole transport auxiliary layer	Compound 1(a)	5
Emitting layer	Compound 1(a')+ ADN + 5% DS-405	30
Electron transport layer	Alq 3	30
Electron injection layer	LiF	One
cathode		Al	200

The structures of NPB, ADN and Alq ₃ used in the above are as follows.

[Examples 2 to 20]-Preparation of blue organic electroluminescent device

In place of the compound 1 used in the formation of the hole transport auxiliary layer of Example 1, each compound (a) shown in Table 3 was used, and the compound 1 used as the first host in the formation of the light emitting layer was replaced with each of the following Table 3 Except for the use of the compound (a') of, it was carried out in the same manner as in Example 1 to prepare the blue organic electroluminescent device of Examples 2 to 20.

[Comparative Example 1]-Fabrication of blue organic electroluminescent device

A blue organic electroluminescent device was manufactured in the same manner as in Example 1, except that Compound 1 used as the first host was not used when forming the emission layer of Example 1.

[Comparative Example 2]-Fabrication of blue organic electroluminescent device

A blue organic electroluminescent device was manufactured in the same manner as in Example 1, except that Compound B was used instead of Compound 1 as the first host used to form the emission layer of Example 1. The structure of compound B used at this time is as follows.

[Evaluation Example 1]

For the organic electroluminescent devices prepared in Examples 1 to 20 and Comparative Examples 1 to 2, respectively, the driving voltage, emission wavelength, and current efficiency at a current density of 10 mA/cm 2 were measured, and the results are shown in Table 3 below. Indicated.

Sample	Hole transport auxiliary layer material (a)	Light emitting layer material		Driving voltage (V)	Emission peak (nm)	Current efficiency (cd/A)
		First host (a')	Weight ratio (a':ADN:DS-405)
Example 1	Compound 1	Compound 1	50: 50: 5	4.2	456	7.5
Example 2	Compound 2	Compound 2	50: 50: 5	4.2	452	7.4
Example 3	Compound 3	Compound 3	50: 50: 5	4.1	450	7.3
Example 4	Compound 4	Compound 4	50: 50: 5	4.1	452	7.2
Example 5	Compound 5	Compound 5	50: 50: 5	4.2	455	7.2
Example 6	Compound 6	Compound 6	50: 50: 5	4.3	452	7.3
Example 7	Compound 7	Compound 7	50: 50: 5	4.2	455	7.4
Example 8	Compound 8	Compound 8	50: 50: 5	4.1	455	7.4
Example 9	Compound 9	Compound 9	50: 50: 5	4.1	452	7.2
Example 10	Compound 10	Compound 10	50: 50: 5	4.0	455	7.2
Example 11	Compound 11	Compound 11	50: 50: 5	4.1	455	7.3
Example 12	Compound 12	Compound 12	50: 50: 5	4.0	458	7.5
Example 13	Compound 13	Compound 13	50: 50: 5	4.2	455	7.5
Example 14	Compound 14	Compound 14	50: 50: 5	4.2	456	7.4
Example 15	Compound 15	Compound 15	50: 50: 5	4.1	455	7.4
Example 16	Compound 16	Compound 16	50: 50: 5	4.1	458	7.3
Example 17	Compound 17	Compound 17	90: 10: 5	4.2	455	7.1
Example 18	Compound 18	Compound 18	30: 70: 5	4.2	456	7.0
Example 19	Compound 19	Compound 19	60: 40: 5	4.3	455	7.2
Example 20	Compound 20	Compound 20	90: 10: 5	4.3	458	7.1
Comparative Example 1	Compound 1	-	0: 100: 5	4.8	458	6.2
Comparative Example 2	Compound 1	B	50: 50: 5	4.5	457	6.4

As shown in Table 1 above, the blue organic electroluminescent devices of Examples 1 to 20 including one of a plurality of hosts in the emission layer as a material for a hole transport auxiliary layer according to the present invention include a single host and an emission layer containing a dopant. While, the blue organic electroluminescent device of Comparative Example 1 including a hole transport auxiliary layer and a plurality of hosts in the light emitting layer were all current efficiency, emission peak, and It was found that it exhibits excellent performance in terms of driving voltage.

Claims (16)

1. anode;

   A cathode disposed opposite to the anode;

   An organic material layer interposed between the anode and the cathode and including a hole transport region, a light emitting layer, and an electron transport region sequentially disposed on the anode

   Including,

   The hole transport region includes a hole injection layer, a hole transport layer, and a hole transport auxiliary layer sequentially disposed on the anode,

   The light emitting layer includes a plurality of hosts and a dopant,

   The plurality of hosts may include a first host identical to the material of the auxiliary hole transport layer; And a second host different from the first host.
2. The method of claim 1,

   The hole transport auxiliary layer satisfies the following relational formula 1, an organic electroluminescent device:

   [Relationship 1]

   

   (In the above formula,

   HOMO _HTL is the HOMO energy level of the hole transport layer,

   HOMO _aHTL is the HOMO energy level of the hole transport auxiliary layer,

   HOMO _EL is the HOMO energy level of the light emitting layer).
3. The method of claim 2,

   The difference between the HOMO energy level of the hole transport auxiliary layer and the HOMO energy level of the hole transport layer is in the range of more than 0 eV to less than 1.0 eV, an organic electroluminescent device:
4. The method of claim 2,

   The difference between the HOMO energy level of the hole transport auxiliary layer and the HOMO energy level of the emission layer is in the range of more than 0 eV to less than 1.0 eV, the organic electroluminescent device.
5. The method of claim 1,

   The hole transport auxiliary layer satisfies the following relational formula 2, an organic electroluminescent device:

   [Relationship 2]

   

   (In the above formula,

   LUMO _aHTL is the LUMO energy level of the hole transport auxiliary layer,

   LUMO _EL is the LUMO energy level of the light emitting layer).
6. The method of claim 5,

   The difference between the absolute value of the LUMO energy level of the hole transport auxiliary layer and the absolute value of the LUMO energy level of the emission layer is in the range of more than 0 eV to less than 1.0 eV, the organic electroluminescent device.
7. The method of claim 1,

   The triplet energy (T1) of the hole transport auxiliary layer is 2.0 eV or more, an organic electroluminescent device.
8. The method of claim 1,

   The second host is a host satisfying the following relations 3 and 4, an organic electroluminescent device:

   [Relationship 3]

   

   [Relationship 4]

   

   (In the above formula,

   LUMO _host-1 is the LUMO energy level of the first host,

   LUMO _host-2 is the LUMO energy level of the second host,

   HOMO _host-1 is the HOMO energy level of the first host,

   HOMO _host-2 is the HOMO energy level of the second host).
9. The method of claim 1,

   The material of the hole transport auxiliary layer and the first host are the same and include a compound represented by the following formula (1), an organic electroluminescent device

   [Formula 1]

   

   (In Formula 1,

   Y ₁ and Y ₂ are the same as or different from each other, each independently a single bond, or is selected from the group consisting of NR ₃ , O, S, and CR ₄ R ₅ , provided that both Y ₁ and Y ₂ are single bonds Is excluded,

   R ₁ to R ₅ are the same as or different from each other, and each independently hydrogen, deuterium, halogen group, cyano group, nitro group, amino group, C ₁ to C ₄₀ alkyl group, C ₂ to C ₄₀ alkenyl group, C ₂ ~ C ₄₀ alkynyl group, C ₃ ~ C ₄₀ cycloalkyl group, 3 to 40 nuclear atoms heterocycloalkyl group, C ₆ ~ C ₆₀ aryl group, 5 to 60 nuclear atoms heteroaryl group, C ₁ ~ C ₄₀ alkyloxy group, C ₆ ~ C ₆₀ aryloxy group, C ₁ ~ C ₄₀ alkylsilyl group, C ₆ ~ C ₆₀ arylsilyl group, C ₁ ~ C ₄₀ alkyl boron group, C ₆ ~ aryl of C ₆₀ boron group, C ₆ ~ C ₆₀ aryl phosphine group, C ₆ ~ C aryl phosphine oxide ₆₀ group and a C ₆ ~, or selected from the group consisting of an aryl amine of the C _60, or adjacent groups bonded to the condensation of Can form a ring;

   m and n are each independently an integer of 0 to 4,

   The alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group, aryloxy group, alkyloxy group, cycloalkyl group, heterocycloalkyl group, arylamine group, alkylsilyl group, alkyl boron group, aryl of the R ₁ to R ₅ A boron group, a phosphine group, a phosphine oxide group, and an arylamine group are each independently hydrogen, deuterium (D), halogen, cyano group, nitro group, C ₁ to C ₄₀ alkyl group, C ₂ to C ₄₀ alkenyl group , C ₂ to C ₄₀ alkynyl group, C ₃ to C ₄₀ cycloalkyl group, heterocycloalkyl group having 3 to 40 nuclear atoms, C ₆ to C ₆₀ aryl group, heteroaryl group having 5 to 60 nuclear atoms, C ₁ ~ C ₄₀ alkyloxy group, C ₆ ~ C ₆₀ aryloxy group, C ₁ ~ C ₄₀ alkylsilyl group, C ₆ ~ C ₆₀ arylsilyl group, C ₁ ~ C ₄₀ alkyl boron group, arylboronic group of _{C 6 ~ C 60, C 6} ~ C 60 of the aryl phosphine group, C ₆ ~ C ₆₀ aryl phosphine oxide group and one substituent at least one selected from the group consisting of an aryl amine of the C ₆ ~ C ₆₀ of Substituted or unsubstituted, and in this case, when the substituents are plural, they may be the same as or different from each other.
10. The method of claim 9,

    The compound represented by Formula 1 is a compound represented by any one of the following Formulas 2 to 15, an organic electroluminescent device:

    [Formula 2]

    

    [Formula 3]

    

    [Formula 4]

    

    [Formula 5]

    

    [Formula 6]

    

    [Formula 7]

    

    [Formula 8]

    

    [Formula 9]

    

    [Formula 10]

    

    [Formula 11]

    

    [Formula 12]

    

    [Formula 13]

    

    [Formula 14]

    

    [Formula 15]

    

    (In Formulas 2 to 15,

    R ₁ to R ₅ , m, and n are each as defined in claim 9).
11. The method of claim 9,

    The compound represented by Formula 1 is a compound represented by any one of the following Formulas 16 to 41, an organic electroluminescent device:

    [Formula 16]

    

    [Formula 17]

    

    [Formula 18]

    

    [Formula 19]

    

    [Formula 20]

    

    [Formula 21]

    

    [Formula 22]

    

    [Formula 23]

    

    [Formula 24]

    

    [Formula 25]

    

    [Formula 26]

    

    [Formula 27]

    

    [Formula 28]

    

    [Chemical Formula 29]

    

    [Formula 30]

    

    [Formula 31]

    

    [Formula 32]

    

    [Formula 33]

    

    [Formula 34]

    

    [Formula 35]

    

    [Formula 36]

    

    [Formula 37]

    

    [Formula 38]

    

    [Formula 39]

    

    [Formula 40]

    

    [Formula 41]

    

    In Formulas 16 to 41,

    R ₁ to R ₅ are each as defined in claim 9,

    a is an integer from 0 to 4,

    R ₆ to R ₉ are the same as or different from each other, and each independently hydrogen, deuterium, halogen group, cyano group, nitro group, amino group, C ₁ to C ₄₀ alkyl group, C ₂ to C ₄₀ alkenyl group, C ₂ to C ₄₀ alkynyl group, C ₃ to C ₄₀ cycloalkyl group, 3 to 40 nuclear atom heterocycloalkyl group, C ₆ to C ₆₀ aryl group, 5 to 60 nuclear atom heteroaryl group, C ₁ to C ₄₀ alkyloxy group, C ₆ ~ C ₆₀ aryloxy group, C ₁ ~ C ₄₀ alkylsilyl group, C ₆ ~ C ₆₀ arylsilyl group, C ₁ ~ C ₄₀ alkyl boron group, C ₆ ~ C ₆₀ arylboronic group, C ₆ ~ C ₆₀ aryl phosphine group, C ₆ ~ C ₆₀ aryl phosphine oxide group, and a C ₆ ~ selected from the group consisting of an aryl amine of the C _60).
12. The method of claim 9,

    At least one of the R ₁ to R ₅ is a substituent represented by one selected from the group consisting of the following structural formulas S1 to S5, an organic electroluminescent device:

    

    (In the above formula,

    * Means the part where the bond with Formula 1 is formed,

    L ₁ is a single bond, or is selected from the group consisting of an arylene group of C ₆ to C _{30 and} a heteroarylene group of 5 to 30 nuclear atoms,

    X ₁ is selected from the group consisting of NAr ₃ , O and S,

    Ar ₁ to Ar ₃ are the same as or different from each other, each independently selected from the group consisting of hydrogen, a C ₁ to C ₄₀ alkyl group, a C ₆ to C ₆₀ aryl group, and a heteroaryl group having 5 to 60 nuclear atoms, ,

    b and c are each 0 or 1,

    The alkyl group, aryl group, and heteroaryl group of Ar ₁ to Ar ₃ are each independently hydrogen, deuterium (D), halogen, cyano group, nitro group, C ₁ to C ₄₀ alkyl group, C ₂ to C ₄₀ alkenyl group, C ₂ to C ₄₀ alkynyl group, C ₃ to C ₄₀ cycloalkyl group, heterocycloalkyl group having 3 to 40 nuclear atoms, C ₆ to C ₆₀ aryl group, heteroaryl group having 5 to 60 nuclear atoms, C ₁ to C ₄₀ alkyloxy group, C ₆ to C ₆₀ aryloxy group, C ₁ to C ₄₀ alkylsilyl group, C ₆ to C ₆₀ arylsilyl group, C ₁ to C ₄₀ alkyl boron group, C group _{of 6} to arylboronic of C _60, C ₆ to C ₆₀ aryl phosphine group, substituted with one substituent at least one selected from the group consisting of an aryl amine of the C ₆ to C ₆₀ aryl phosphine oxide group, and a C ₆ to C ₆₀ of Or unsubstituted, in which case, when the substituents are plural, they may be the same or different from each other).
13. The method of claim 9,

    The compound represented by Formula 1 is any one of the following compounds 1 to 20, an organic electroluminescent device:

    

    .
14. The method of claim 1,

    The first host and the second host are included in a weight ratio of 30:70 to 90:10, an organic electroluminescent device.
15. The method of claim 1,

    The electron transport region may include an electron transport layer disposed on the emission layer; And an electron injection layer disposed between the electron transport layer and the cathode.
16. The method of claim 15,

    The electron transport region further comprises an electron transport auxiliary layer disposed between the emission layer and the electron transport layer.

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