KR20210141825A - Benzazole derivatives and organic electroluminescent device including the same - Google Patents

Abstract

The present invention relates to a benzazole derivative which contributes improvement of substantial service life of an organic electroluminescence device by absorbing a high-energy external light source in the UV region effectively to minimize damages of the organic materials in the organic electroluminescence device. The present invention also relates to an organic electroluminescence device including: a first electrode; a second electrode; at least one organic layer disposed between the first electrode and the second electrode; and a capping layer, wherein the organic layer or capping layer includes a benzazole derivative represented by chemical formula 1. In chemical formula 1, each substituent is the same as defined in the specificiation.

Description

Benzazole derivatives and organic electroluminescent device including the same

The present invention relates to a benzazole derivative and an organic electroluminescent device including the same, and to make an organic electroluminescent device including a capping layer have low refractive index by using the benzazole derivative.

OLED (Organic Light Emitting Diodes) is attracting attention as a display using the self-luminescence phenomenon in the display industry.

In OLED, a study of carrier injection electroluminescence (EL) using a single crystal of an anthracene aromatic hydrocarbon was first attempted by Pope et al. in 1963. From these studies, basic mechanisms such as charge injection, recombination, exciton generation, and light emission in organic materials and electroluminescence properties have been understood and studied.

In particular, in order to increase the luminous efficiency, various approaches are being made, such as changing the structure of the device and developing materials [Sun, S., Forrest, S. R., Appl. Phys. Lett. 91, 263503 (2007)/Ken-Tsung Wong, Org. Lett., 7, 2005, 5361-5364].

The basic structure of an OLED display is generally an anode, a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), and an electron transport layer (ETL). ), and a multilayer structure of a cathode, and a sandwich structure in which an electron organic multilayer film is formed between two electrodes.

In general, the organic light emitting phenomenon refers to a phenomenon in which electric energy is converted into light energy using an organic material. An organic light emitting device using an organic light emitting phenomenon typically has a structure including an anode and a cathode and an organic material layer therebetween. Here, the organic material layer is often formed of a multi-layer structure composed of different materials in order to increase the efficiency and stability of the organic light emitting device, and may include, for example, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and the like. When a voltage is applied between the two electrodes in the structure of the organic light emitting device, holes are injected into the organic material layer from the anode and electrons from the cathode are injected into the organic material layer, and excitons are formed when the injected holes and electrons meet It lights up when it falls into a state. Such an organic light emitting device is known to have characteristics such as self-luminescence, high luminance, high efficiency, low driving voltage, wide viewing angle, high contrast, and high-speed response.

A material used as an organic material layer in an organic light emitting device may be classified into a light emitting material and a charge transport material, for example, a hole injection material, a hole transport material, an electron transport material, an electron injection material, and the like, according to functions.

The light-emitting material includes blue, green, and red light-emitting materials depending on the light-emitting color, and yellow and orange light-emitting materials required to realize better natural colors. In addition, in order to increase color purity and increase luminous efficiency through energy transfer, a host/dopant system may be used as a light emitting material. The principle is that when a small amount of a dopant having a smaller energy band gap and excellent luminous efficiency than the host constituting the light emitting layer is mixed in the light emitting layer in a small amount, excitons generated from the host are transported to the dopant to emit light with high efficiency. At this time, since the wavelength of the host moves to the wavelength band of the dopant, light having a desired wavelength can be obtained according to the type of dopant used.

In order to sufficiently express the excellent characteristics of the above-mentioned organic light emitting device, materials constituting the organic material layer in the device, such as a hole injection material, a hole transport material, a light emitting material, an electron transport material, an electron injection material, etc. The performance of the organic light emitting device is recognized by the products.

However, as the commercialization of the organic light emitting device is made and time passes, the need for other characteristics in addition to the light emitting characteristic of the organic light emitting device itself is emerging.

Since the organic light emitting diode is exposed to an external light source for a large amount of time, it is in an environment exposed to ultraviolet rays having high energy. Accordingly, there is a problem in that the organic material constituting the organic light emitting device is continuously affected. In order to prevent exposure to such a high energy light source, the problem can be solved by applying a capping layer having ultraviolet absorption characteristics to the organic light emitting diode.

In general, it is known that the viewing angle characteristics of an organic light emitting device are wide, but a significant deviation occurs depending on the viewing angle from the viewpoint of the light source spectrum. This is due to the occurrence of a deviation between the appropriate refractive indices.

In general, the larger the required refractive index value of blue and the longer the wavelength, the smaller the required refractive index value. Accordingly, it is necessary to develop a material for forming a capping layer that simultaneously satisfies the above-mentioned ultraviolet absorption characteristics and an appropriate refractive index.

The efficiency of the organic light emitting diode can be generally divided into internal luminescent efficiency and external luminescent efficiency. The internal luminous efficiency is related to the efficiency of the formation of excitons in the organic layer for light conversion to take place.

The external luminous efficiency refers to the efficiency at which light generated in the organic layer is emitted to the outside of the organic light emitting device.

In order to improve the overall efficiency, it is necessary to increase the external luminous efficiency as well as the internal luminous efficiency. There is a demand for the development of a capping layer (CPL, light efficiency improving layer) material having an excellent ability to increase external luminous efficiency.

On the other hand, the top device structure of the resonant structure is compared with the bottom device structure of the non-resonant structure, since the formed light is reflected by the anode, which is a reflective film, and comes out toward the cathode, the optical energy loss due to SPP (Surface Plasmon Polariton) is reduced. Big.

Therefore, one of the important methods for improving the shape and efficiency of the EL spectrum is to use a light efficiency improving layer (capping layer) for the top cathode.

In general, in SPP, four types of metals are mainly used for electron emission: Al, Pt, Ag, and Au, and surface plasmons are generated on the surface of the metal electrode. For example, when the cathode is used as Ag, the emitted light is quenched by SPP (light energy loss due to Ag) and the efficiency is reduced.

On the other hand, when a capping layer (light efficiency improvement layer) is used, SPP occurs at the interface between the MgAg electrode and the organic material. electric) Polarized light is dissipated on the capping layer surface (light efficiency improving layer surface) in the vertical direction by an evanescent wave, and TM (Transverse magnetic) polarized light moving along the cathode and the capping layer is a surface plasma resonance (Surface) The amplification of the wavelength occurs due to plasma resonance, which increases the intensity of the peak, enabling high efficiency and effective color purity control.

However, it is still required to develop materials and structures necessary for improving various properties in a balanced manner along with improvement of efficiency and color purity in organic light emitting devices.

Republic of Korea Patent Publication No. 2016-0062307 (Title of the invention: organic light emitting display device including a high refractive index capping layer)

SUMMARY OF THE INVENTION It is an object of the present invention to provide a capping layer material for an organic light emitting device, which can improve luminous efficiency and lifespan, and at the same time improve viewing angle characteristics.

It is an object of the present invention to provide an organic electroluminescent device with high efficiency and long life, including a capping layer having a controlled refractive index, in particular to improve the light extraction rate of the organic electroluminescent device.

The present invention is a first electrode; an organic material layer disposed on the first electrode; a second electrode disposed on the organic material layer; and a capping layer disposed on the second electrode, wherein the organic material layer or the capping layer provides an organic electroluminescent device including a benzazole derivative represented by Formula 1 below.

[Formula 1]

In Formula 1,

Z ₁ is O, S or NR with the proviso that R is phenyl;

X ₁ , X ₂ , X _{3 ,} X ₄ and X ₅ are each independently CH or N,

Ar ₁ is selected from H, a methyl group, a tert-butyl group, F, CF ₃ , CN and Si(CH ₃ ) ₃ ,

L ₁ is a direct bond; or a substituted or unsubstituted arylene group; Or a substituted or unsubstituted heteroarylene group;

n is an integer from 0 to 5,

R ₁ to R ₅ are each independently any one selected from an alkyl group, H, F, CF ₃ , CN, and Si(CH ₃ ) _{3 ,}

m is an integer of 1 to 2.

The compound described herein may be used as a material for a capping layer and/or an organic material layer of an organic light emitting device.

In an organic light emitting device using the compound described in the present specification as a low refractive index capping layer (light efficiency improving layer), it is possible to significantly improve luminous efficiency and color purity according to a reduction in the emission spectrum half width.

The organic electroluminescent device according to the present invention continuously introduces a thin film of a high refractive organic material and a thin film of low refractive index on an MgAg electrode, thereby improving the viewing angle and luminous efficiency of light extracted into the air due to the waveguide resonance phenomenon.

1 shows a first electrode 110, a hole injection layer 210, a hole transport layer 215, a light emitting layer 220, an electron transport layer 230, and an electron injection layer on a substrate 100 according to an embodiment of the present invention. An example of an organic light emitting device in which 235 , the second electrode 120 , and the capping layer 300 are sequentially stacked is shown.
2 is a graph showing the refraction and absorption characteristics of light when using a benzazole derivative according to an embodiment of the present invention.

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

Since the present invention can have various changes and can have various forms, specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed form, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

In describing each figure, like reference numerals have been used for like elements. In the accompanying drawings, the dimensions of the structures are enlarged than the actual size for clarity of the present invention. Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. The singular expression includes the plural expression unless the context clearly dictates otherwise.

In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It is to be understood that it does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof. Also, when a part of a layer, film, region, plate, etc. is said to be “on” another part, this includes not only cases where it is “directly on” another part, but also cases where there is another part in between.

As used herein, "substituted or unsubstituted" is a deuterium atom, a halogen atom, a cyano group, a nitro group, an amino group, a hydroxy group, a silyl group, a boron group, a phosphine oxide group, a phosphine sulfide group, an alkyl group, an alkoxy group, an alke group It may mean unsubstituted or substituted with one or more substituents selected from the group consisting of a nyl group, an aryl group, a heteroaryl group, and a heterocyclic group. In addition, each of the substituents exemplified above may be substituted or unsubstituted. For example, a biphenyl group may be interpreted as an aryl group or a phenyl group substituted with a phenyl group.

In the present specification, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom or an iodine atom.

In the present specification, the alkyl group may be linear, branched or cyclic. Carbon number of an alkyl group is 1 or more and 50 or less, 1 or more and 30 or less, 1 or more and 20 or less, 1 or more and 10 or less, or 1 or more and 6 or less. Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, t-butyl group, i-butyl group, 2-ethylbutyl group, 3, 3-dimethylbutyl group , n-pentyl group, i-pentyl group, neopentyl group, t-pentyl group, cyclopentyl group, 1-methylpentyl group, 3-methylpentyl group, 2-ethylpentyl group, 4-methyl-2-pentyl group , n-hexyl group, 1-methylhexyl group, 2-ethylhexyl group, 2-butylhexyl group, cyclohexyl group, 4-methylcyclohexyl group, 4-t-butylcyclohexyl group, n-heptyl group, 1 -Methylheptyl group, 2,2-dimethylheptyl group, 2-ethylheptyl group, 2-butylheptyl group, n-octyl group, t-octyl group, 2-ethyloctyl group, 2-butyloctyl group, 2-hexyl group Siloctyl group, 3,7-dimethyloctyl group, cyclooctyl group, n-nonyl group, n-decyl group, adamantyl group, 2-ethyldecyl group, 2-butyldecyl group, 2-hexyldecyl group, 2-ox Tyldecyl group, n-undecyl group, n-dodecyl group, 2-ethyldodecyl group, 2-butyldodecyl group, 2-hexyldodecyl group, 2-octyldodecyl group, n-tridecyl group, n-tetradecyl group, n -pentadecyl group, n-hexadecyl group, 2-ethylhexadecyl group, 2-butylhexadecyl group, 2-hexylhexadecyl group, 2-octylhexadecyl group, n-heptadecyl group, n-octadecyl group , n-nonadecyl group, n-icosyl group, 2-ethyl icosyl group, 2-butyl icosyl group, 2-hexyl icosyl group, 2-octyl icosyl group, n-henicosyl group, n-docosyl group, n-tricho Sil group, n-tetracosyl group, n-pentacosyl group, n-hexacosyl group, n-heptacosyl group, n-octacosyl group, n-nonacosyl group, and n-triacontyl group, etc. are mentioned, It is not limited to these.

As used herein, the hydrocarbon ring group means any functional group or substituent derived from an aliphatic hydrocarbon ring. The hydrocarbon ring group may be a saturated hydrocarbon ring group having 5 to 20 ring carbon atoms.

As used herein, the aryl group means any functional group or substituent derived from an aromatic hydrocarbon ring. The aryl group may be a monocyclic aryl group or a polycyclic aryl group. The number of ring carbon atoms of the aryl group may be 6 or more and 30 or less, 6 or more and 20 or less, or 6 or more and 15 or less. Examples of the aryl group include a phenyl group, a naphthyl group, a fluorenyl group, an anthracenyl group, a phenanthryl group, a biphenyl group, a terphenyl group, a quarterphenyl group, a quinkphenyl group, a sexyphenyl group, a triphenylenyl group, a pyrenyl group, a peryleneyl group, a naphtha group Although a cenyl group, a pyrenyl group, a benzo fluoranthenyl group, a chrysenyl group, etc. can be illustrated, it is not limited to these.

In the present specification, the fluorenyl group may be substituted, and two substituents may be bonded to each other to form a spiro structure.

In the present specification, the heteroaryl group may be a heteroaryl group including at least one of O, N, P, Si and S as a heterogeneous element. The N and S atoms may optionally be oxidized and the N atom(s) may optionally be quaternized. The number of ring carbon atoms in the heteroaryl group is 2 or more and 30 or less, or 2 or more and 20 or less. The heteroaryl group may be a monocyclic heteroaryl group or a polycyclic heteroaryl group. The polycyclic heteroaryl group may have, for example, a bicyclic or tricyclic structure.

Examples of the heteroaryl group include a thiophene group, a furan group, a pyrrole group, an imidazole group, a pyrazolyl group, a thiazole group, an oxazole group, an oxadiazole group, a triazole group, a pyridine group, a bipyridine group, a pyrimidine group, a triazine group , tetrazine group, triazole group, tetrazole group, acridyl group, pyridazine group, pyrazinyl group, quinoline group, quinazoline group, quinoxaline group, phenoxazine group, phthalazine group, pyridopyrimidine group, pyridopyrazino group Pyrazine group, isoquinoline group, cinnol group, indole group, isoindole group, indazole group, carbazole group, N-arylcarbazole group, N-heteroarylcarbazole group, N-alkylcarbazole group, benzoxazole group, benzoimidazole group , benzothiazole group, benzocarbazole group, benzothiophene group, benzothiophene group, benzoisothiazolyl, benzoisoxazolyl, dibenzothiophene group, thienothiophene group, benzofuran group, phenanthroline group, phenanthridine group , thiazole group, isoxazole group, oxadiazole group, thiadiazole group, isothiazole group, isoxazole group, phenothiazine group, benzodioxol group, dibenzosilol group and dibenzofuran group, isobenzofuran group, etc., It is not limited to these. In addition, there are N-oxide aryl groups corresponding to the monocyclic heteroaryl group or polycyclic heteroaryl group, for example, quaternary salts such as pyridyl N-oxide group, quinolyl N-oxide group, etc., but these not limited

In the present specification, the silyl group includes an alkyl silyl group and an aryl silyl group. Examples of the silyl group include a trimethylsilyl group, a triethylsilyl group, a t-butyldimethylsilyl group, a vinyldimethylsilyl group, a propyldimethylsilyl group, a triphenylsilyl group, a diphenylsilyl group, a phenylsilyl group, and the like. not limited

In the present specification, the boron group includes an alkyl boron group and an aryl boron group. Examples of the boron group include, but are not limited to, a trimethylboron group, a triethylboron group, a t-butyldimethylboron group, a triphenylboron group, a diphenylboron group, and a phenylboron group.

In the present specification, the alkenyl group may be straight-chain or branched. Although carbon number is not specifically limited, 2 or more and 30 or less, 2 or more and 20 or less, or 2 or more and 10 or less. Examples of the alkenyl group include, but are not limited to, a vinyl group, a 1-butenyl group, a 1-pentenyl group, a 1,3-butadienyl aryl group, a styrenyl group, and a styryl vinyl group.

In the present specification, examples of the arylamine group include a substituted or unsubstituted monoarylamine group, a substituted or unsubstituted diarylamine group, or a substituted or unsubstituted triarylamine group. The aryl group in the arylamine group may be a monocyclic aryl group, and may include a polycyclic aryl group or a monocyclic aryl group and a polycyclic aryl group at the same time.

Specific examples of the arylamine group include a phenylamine group, a naphthylamine group, a biphenylamine group, an anthracenylamine group, a 3-methyl-phenylamine group, a 4-methyl-naphthylamine group, and a 2-methyl-biphenylamine group. group, 9-methyl-anthracenylamine group, diphenyl amine group, phenyl naphthylamine group, ditolyl amine group, phenyl tolyl amine group, carbazole and triphenyl amine group, but is not limited thereto.

In the present specification, examples of the heteroallylamine group include a substituted or unsubstituted monoheteroarylamine group, a substituted or unsubstituted diheteroarylamine group, or a substituted or unsubstituted triheteroarylamine group. The heteroaryl group in the heteroarylamine group may be a monocyclic heterocyclic group or a polycyclic heterocyclic group. The heteroarylamine group including two or more heterocyclic groups may include a monocyclic heterocyclic group, a polycyclic heterocyclic group, or a monocyclic heterocyclic group and a polycyclic heterocyclic group at the same time.

In the present specification, the aryl heteroarylamine group refers to an amine group substituted with an aryl group and a heterocyclic group.

As used herein, "adjacent group" may mean a substituent substituted on an atom directly connected to the atom in which the substituent is substituted, another substituent substituted on the atom in which the substituent is substituted, or a substituent sterically closest to the substituent. have. For example, in 1,2-dimethylbenzene, two methyl groups can be interpreted as “adjacent groups” to each other, and in 1,1-diethylcyclopentene, 2 The two ethyl groups can be interpreted as “adjacent groups” to each other.

Hereinafter, the benzazole derivative compound used in the organic material layer and/or the capping layer will be described.

The benzazole derivative compound according to an embodiment of the present invention is represented by the following formula (1).

[Formula 1]

In Formula 1,

Z ₁ is O, S or NR with the proviso that R is phenyl;

X ₁ , X ₂ , X _{3 ,} X ₄ and X ₅ are each independently CH or N,

Ar ₁ is selected from H, a methyl group, a tert-butyl group, F, CF ₃ , CN and Si(CH ₃ ) ₃ ,

L ₁ is a direct bond; or a substituted or unsubstituted arylene group; Or a substituted or unsubstituted heteroarylene group;

n is an integer from 1 to 5,

R ₁ to R ₅ are each independently any one selected from an alkyl group, H, F, CF ₃ , CN, and Si(CH ₃ ) _{3 ,}

m is an integer of 1 to 2.

According to an embodiment of the present invention, in Formula 1, L ₁ Is a substituted or unsubstituted phenyl group; a substituted or unsubstituted pyridyl group; a substituted or unsubstituted naphthyl group; a substituted or unsubstituted anthracene group; a substituted or unsubstituted phenanthrine group; and a benzazole derivative including a compound that is a substituted or unsubstituted phenanthridine group.

In an embodiment of the present invention, the benzazole derivative represented by Formula 1 may be any one selected from compounds represented by Formula 2 and Formula 3, and the following compounds may be further substituted.

[Formula 2]

[Formula 3]

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 and 2 .

1 is a cross-sectional view schematically illustrating an organic light emitting diode according to an embodiment of the present invention. Referring to FIG. 1 , in an organic light emitting device according to an exemplary embodiment, a first electrode 110 , a hole injection layer 210 , a hole transport layer 215 , a light emitting layer 220 , and electrons are sequentially stacked on a substrate 100 . It may include a transport layer 230 , an electron injection layer 235 , a second electrode 120 , and a capping layer 300 .

The first electrode 110 and the second electrode 120 are disposed to face each other, and the organic material layer 200 may be disposed between the first electrode 110 and the second electrode 120 . The organic material layer 200 may include a hole injection layer 210 , a hole transport layer 215 , a light emitting layer 220 , an electron transport layer 230 , and an electron injection layer 235 .

Meanwhile, the capping layer 300 presented in the present invention is a functional layer deposited on the second electrode 120 and includes an organic material according to Chemical Formula 1 of the present invention.

In the organic light emitting diode according to the exemplary embodiment shown in FIG. 1 , the first electrode 110 has conductivity. The first electrode 110 may be formed of a metal alloy or a conductive compound. The first electrode 110 is generally an anode, but the function as an electrode is not limited.

The first electrode 110 may be formed by depositing an electrode material on the substrate 100 using a deposition method, electron beam evaporation, or sputtering. The material of the first electrode 110 may be selected from materials having a high work function to facilitate injection of holes into the organic light emitting device.

The capping layer 300 proposed in the present invention is applied when the emission direction of the organic light emitting device is top emission, and thus the first electrode 110 uses a reflective electrode. These materials include Mg (magnesium), Al (aluminum), Al-Li (aluminum-lithium), Ca (calcium), Mg-In (magnesium-indium), Mg-Ag (magnesium-silver) and It can also be manufactured using the same metal. In recent years, carbon substrate flexible electrode materials such as CNT (carbon nanotube) and graphene (graphene) may be used.

The organic material layer 200 may be formed of a plurality of layers. When the organic material layer 200 is a plurality of layers, the organic material layer 200 includes the hole transport regions 210 to 215 disposed on the first electrode 110 , the light emitting layer 220 disposed on the hole transport region, and the light emitting layer. It may include electron transport regions 230 to 235 disposed on 220 .

The capping layer 300 of an embodiment includes an organic compound represented by Chemical Formula 1 to be described later.

The hole transport regions 210 to 215 are provided on the first electrode 110 . The hole transport regions 210 to 215 may include at least one of a hole injection layer 210 , a hole transport layer 215 , a hole buffer layer, and an electron blocking layer (EBL). In general, since hole mobility is faster than electron mobility, it has a thicker thickness than the electron transport region.

The hole transport regions 210 to 215 may have a single layer made of a single material, a single layer made of a plurality of different materials, or a multilayer structure having a plurality of layers made of a plurality of different materials.

For example, the hole transport regions 210 to 215 may have a single-layer structure of the hole injection layer 210 or the hole transport layer 215 , or may have a single-layer structure including a hole injection material and a hole transport material. have. In addition, the hole transport regions 210 to 215 have a single-layer structure made of a plurality of different materials, or a hole injection layer 210/hole transport layer 215 stacked sequentially from the first electrode 110, Hole injection layer 210 / hole transport layer 215 / hole buffer layer, hole injection layer 210 / hole buffer layer, hole transport layer 215 / hole buffer layer, or hole injection layer 210 / hole transport layer 215 / electron It may have a structure of the blocking layer EBL, but the embodiment is not limited thereto.

The hole injection layer 210 of the hole transport regions 210 to 215 may be formed on the anode by various methods, such as a vacuum deposition method, a spin coating method, a casting method, and an LB method. When the hole injection layer 210 is formed by vacuum deposition, the deposition conditions are 100 to 500 Å depending on the compound used as the material for the hole injection layer 210, the structure and thermal characteristics of the hole injection layer 210, etc. The deposition rate can be freely controlled by setting the deposition rate to around 1 Å/s, and is not limited to specific conditions. In the case of forming the hole injection layer 210 by the spin coating method, the coating conditions are different depending on the characteristics between the compound used as the hole injection layer 210 material and the layers formed as the interface, but for an even film formation, the coating speed, coating After that, heat treatment to remove the solvent is required.

The hole transport regions 210 to 215 are, for example, m-MTDATA, TDATA, 2-TNATA, NPB, β-NPB, TPD, Spiro-TPD, Spiro-NPB, methylated-NPB, TAPC, HMTPD, TCTA. (4,4',4"-tris(N-carbazolyl)triphenylamine (4,4',4"-tris(Ncarbazolyl) triphenylamine)), Pani/DBSA (Polyaniline/Dodecylbenzenesulfonic acid: polyaniline/dodecylbenzene sulfonic acid), PEDOT/PSS (Poly(3,4-ethylenedioxythiophene) /Poly(4-styrene sulfonate):poly(3,4-ethylenedioxythiophene) /poly(4-styrenesulfonate)), Pani/CSA ( Polyaniline/Camphor sulfonicacid: polyaniline/camphorsulfonic acid), PANI/PSS (Polyaniline)/Poly(4-styrenesulfonate):polyaniline)/poly(4-styrenesulfonate)), and the like.

The thickness of the hole transport regions 210 to 215 may be about 100 to about 10,000 Å, and the corresponding organic material layers in each of the hole transport regions 210 to 215 are not limited to the same thickness. For example, if the hole injection layer 210 has a thickness of 50 Å, the hole transport layer 215 may have a thickness of 1000 Å and the electron blocking layer may have a thickness of 500 Å. The thickness condition of the hole transport regions 210 to 215 may be determined to a degree that satisfies the efficiency and lifespan within a range in which the increase in the driving voltage of the organic light emitting device does not increase. The organic layer 200 includes a hole injection layer 210, a hole transport layer 215, a functional layer having both a hole injection function and a hole transport function, a buffer layer, an electron blocking layer, a light emitting layer 220, a hole blocking layer, an electron transport layer. 230 , the electron injection layer 235 , and one or more layers selected from the group consisting of a functional layer having an electron transport function and an electron injection function at the same time.

The hole transport regions 210 to 215 may use doping to improve properties like the light emitting layer 220 , and doping of a charge-generating material into the hole transport regions 210 to 215 may improve the electrical properties of the organic light emitting device. can

The charge-generating material is generally made of a material having a very low HOMO and LUMO. For example, the LUMO of the charge-generating material has a value similar to the HOMO of the hole transport layer 215 material. Due to the low LUMO, holes are easily transferred to the adjacent hole transport layer 215 by using the electron vacancy characteristic of the LUMO, thereby improving electrical properties.

The charge-generating material may be, for example, a p-dopant. The p-dopant may be one of a quinone derivative, a metal oxide, and a cyano group-containing compound, but is not limited thereto. For example, non-limiting examples of the p-dopant include tetracyanoquinonedimethane (TCNQ) and 2,3,5,6-tetrafluoro-tetracyano-1,4-benzoquinonedimethane quinone derivatives such as phosphorus (F4-TCNQ) and the like; metal oxides such as tungsten oxide and molybdenum oxide; and a cyano group-containing compound such as Compound 2-22 below, but is not limited thereto.

In addition to the aforementioned materials, the hole transport regions 210 to 215 may further include a charge generating material to improve conductivity. The charge generating material may be uniformly or non-uniformly dispersed in the hole transport regions 210 to 215 . The charge generating material may be, for example, a p-dopant. The p-dopant may be one of a quinone derivative, a metal oxide, and a cyano group-containing compound, but is not limited thereto. For example, non-limiting examples of p-dopants include quinone derivatives such as TCNQ (Tetracyanoquinodimethane) and F4-TCNQ (2,3,5,6-tetrafluoro-tetracyanoquinodimethane), metal oxides such as tungsten oxide and molybdenum oxide, etc. may be mentioned, but is not limited thereto.

As described above, the hole transport regions 210 to 215 may further include at least one of a hole buffer layer and an electron blocking layer in addition to the hole injection layer 210 and the hole transport layer 215 . The hole buffer layer may increase light emission efficiency by compensating for a resonance distance according to a wavelength of light emitted from the emission layer 220 . As a material included in the hole buffer layer, a material that may be included in the hole transport regions 210 to 215 may be used.

The electron blocking layer is a layer serving to prevent electron injection from the electron transport region 230 to 235 to the hole transport region 210 to 215 . The electron blocking layer may use a material having a high T1 value so that excitons formed in the light emitting layer 220 do not diffuse into the hole transport regions 210 to 215 as well as to block electrons moving to the hole transport region. For example, a host of the light emitting layer 220 having a generally high T _{1 value may be used as the electron blocking layer material.}

The emission layer 220 is provided on the hole transport regions 210 to 215 . The light emitting layer 220 may have a thickness of, for example, about 100 Å to about 1000 Å, or about 100 Å to about 300 Å. The light emitting layer 220 may have a single layer made of a single material, a single layer made of a plurality of different materials, or a multilayer structure having a plurality of layers made of a plurality of different materials.

The light emitting layer 220 is a region where holes and electrons meet to form excitons. The material constituting the light emitting layer 220 must have an appropriate energy band gap to exhibit high light emitting characteristics and a desired light emitting color, and generally serve as both a host and a dopant. It consists of two materials, but is not limited thereto.

The host may include at least one of the following TPBi, TBADN, ADN (also referred to as “DNA”), CBP, CDBP, TCP, and mCP, and if the properties are appropriate, the material is not limited thereto.

The dopant of the light emitting layer 220 according to an embodiment may be an organometallic complex. The general dopant content may be selected from 0.01 to 20%, but in some cases, it is not limited thereto.

The electron transport regions 230 to 235 are provided on the emission layer 220 . The electron transport regions 230 to 235 may include at least one of a hole blocking layer, an electron transport layer 230 , and an electron injection layer 235 , but are not limited thereto.

The electron transport regions 230 to 235 may have a single layer made of a single material, a single layer made of a plurality of different materials, or a multilayer structure having a plurality of layers made of a plurality of different materials.

For example, the electron transport regions 230 to 235 may have a single-layer structure of the electron injection layer 235 or the electron transport layer 230 , or may have a single-layer structure including an electron injection material and an electron transport material. have. In addition, the electron transport regions 230 to 235 have a single layer structure made of a plurality of different materials, or the electron transport layer 230/electron injection layer 235 and hole blocking layer are sequentially stacked from the light emitting layer 220 . It may have a layer/electron transport layer 230/electron injection layer 235 structure, but is not limited thereto. The thickness of the electron transport regions 230 to 235 may be, for example, about 1000 Å to about 1500 Å.

The electron transport regions 230 to 235 may include a vacuum deposition method, a spin coating method, a cast method, a Langmuir-Blodgett (LB) method, an inkjet printing method, a laser printing method, and a laser induced thermal imaging (LITI) method. method can be used.

When the electron transport regions 230 to 235 include the electron transport layer 230 , the electron transport region 230 may include an anthracene-based compound. However, the present invention is not limited thereto, and the electron transport region is, for example, Alq3(Tris(8-hydroxyquinolinato)aluminum),1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene,2 ,4,6-tris(3'-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine,2-(4-(N-phenylbenzoimidazolyl-1-ylphenyl)-9,10 -dinaphthylanthracene,TPBi(1,3,5-Tri(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl),BCP(2,9-Dimethyl-4,7-diphenyl-1,10- phenanthroline), Bphen(4,7-Diphenyl-1,10-phenanthroline),TAZ(3-(4-Biphenylyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole),NTAZ(4 -(Naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole),tBu-PBD(2-(4-Biphenylyl)-5-(4-tert-butylphenyl)-1, 3,4-oxadiazole), BAlq(Bis(2-methyl-8-quinolinolato-N1,O8)-(1,1'-Biphenyl-4-olato)aluminum), Bebq2(berylliumbis(benzoquinolin-10-olate), ADN (9,10-di(naphthalene-2-yl)anthracene) and mixtures thereof may be included.

Since the electron transport layer 230 is selected as a material having a fast electron mobility or a slow electron mobility according to the structure of the organic light emitting device, various materials need to be selected, and in some cases, Liq or Li may be doped.

The thickness of the electron transport layers 230 may be about 100 Å to about 1000 Å, for example, about 150 Å to about 500 Å. When the thickness of the electron transport layers 230 satisfies the above-described range, a satisfactory electron transport characteristic may be obtained without a substantial increase in driving voltage.

When the electron transport regions 230 to 235 include the electron injection layer 235 , the electron transport regions 230 to 235 select a metal material that facilitates electron injection, LiF, Lithium quinolate (LiQ), A _{lanthanide metal such as Li 2} O, BaO, NaCl, CsF, and Yb, or a metal halide such as RbCl or RbI may be used, but is not limited thereto.

The electron injection layer 235 may also be made of a material in which an electron transport material and an insulating organo metal salt are mixed. The organometallic salt may be a material having an energy band gap of about 4 eV or more. Specifically, for example, the organometallic salt may include metal acetate, metal benzoate, metal acetoacetate, metal acetylacetonate, or metal stearate. can The electron injection layers 235 may have a thickness of about 1 Å to about 100 Å, or about 3 Å to about 90 Å. When the thickness of the electron injection layers 235 satisfies the above-described range, a satisfactory electron injection characteristic may be obtained without a substantial increase in driving voltage.

As described above, the electron transport regions 230 to 235 may include a hole blocking layer. The hole blocking layer includes, for example, at least one of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-diphenyl-1,10-phenanthroline (Bphen), and Balq. can, but is not limited thereto.

The second electrode 120 is provided on the electron transport regions 230 to 235 . The second electrode 120 may be a common electrode or a cathode. The second electrode 120 may be a transmissive electrode or a transflective electrode. Unlike the first electrode 110 , the second electrode 120 may use a combination of a metal, an electrically conductive compound, an alloy, etc. having a relatively low work function.

The second electrode 120 is a transflective electrode or a reflective electrode. The second electrode 120 includes Li (lithium), Mg (magnesium), Al (aluminum), Al-Li (aluminum-lithium), Ca (calcium), Mg-In (magnesium-indium), and Mg-Ag (magnesium). -silver) or a compound or mixture containing them (eg, a mixture of Ag and Mg). Or a plurality of layer structures including a reflective or semi-transmissive film formed of the above material and a transparent conductive film formed of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium tin zinc oxide (ITZO), etc. can be

Although not shown, the second electrode 120 may be connected to the auxiliary electrode. When the second electrode 120 is connected to the auxiliary electrode, the resistance of the second electrode 120 may be reduced.

An electrode and an organic material layer are formed on the illustrated substrate 100. In this case, the substrate 100 may use a rigid or flexible material, for example, soda lime glass, alkali-free glass, aluminosilicate glass as the rigid material. PC (polycarbonate), PES (polyether sulfone), COC (cyclic oliphene copolymer), PET (polyethylene terephthalate), PEN (polyethylene naphthalate), etc. can be used as a soft material. .

In the organic light emitting device, as a voltage is applied to each of the first electrode 110 and the second electrode 120 , holes injected from the first electrode 110 pass through the hole transport regions 210 to 215 to the emission layer The electrons are moved to 220 , and the electrons injected from the second electrode 120 are moved to the emission layer 220 through the electron transport regions 230 to 235 . Electrons and holes recombine in the emission layer 220 to generate excitons, and the excitons fall from the excited state to the ground state and emit light.

The optical path generated by the light emitting layer 220 may exhibit a very different tendency according to the refractive index of the organic/inorganic materials constituting the organic light emitting device. Light passing through the second electrode 120 may pass only light transmitted at an angle smaller than the critical angle of the second electrode 120 . Lights contacting the second electrode 120 larger than the other critical angles are totally reflected or reflected, so that they are not emitted to the outside of the organic light emitting diode.

When the refractive index of the capping layer 300 is high, it contributes to the improvement of luminous efficiency by reducing such total reflection or reflection, and also, when it has an appropriate thickness, it contributes to high efficiency improvement and color purity by maximizing the micro-cavity phenomenon. .

The capping layer 300 is positioned at the outermost part of the organic light emitting device, and has a great influence on device characteristics without affecting the driving of the device at all. Therefore, the capping layer 300 is important both in terms of both an internal protection role of the organic light emitting device and improvement of device characteristics. Organic materials absorb light energy in a specific wavelength region, which depends on the energy band gap. If this energy bandgap is adjusted for the purpose of absorbing the UV region that can affect the organic materials inside the organic light emitting device, the capping layer 300 can be used for the purpose of protecting the organic light emitting device including improving optical properties. have.

The organic light emitting device according to the present specification may be a top emission type, a back emission type, or a double side emission type depending on the material used.

Hereinafter, examples will be given to describe the present specification in detail. However, the embodiments according to the present specification may be modified in various other forms, and the scope of the present application is not to be construed as being limited to the embodiments described below. The embodiments of the present application are provided to more completely explain the present specification to those of ordinary skill in the art.

[Example]

intermediate Synthesis example 1: Synthesis of intermediate (3)

(Synthesis of Intermediate (1))

In a 2-neck 1 L flask, 2- (4-bromophenyl) benzoxazole (2- (4-bromophenyl) benzoxazole) 35.0 g (127.6 mmol), bis (pinacolato) diboron (bis (pinacolato) diboron) 42.1 g (165.9 mmol), Pd (dppf) Cl 2 - CH 2 Cl 2 2.8 g (3.8 mmol), KOAc 25.1 g (255.3 mmol) and stirred under reflux in 1,4-dioxane, and then 18 hours a mixture of 350 mL did. After the reaction was completed, it was cooled to room temperature, purified water was added, and the mixture was extracted with ethyl acetate and the solvent was removed under reduced pressure. The obtained reaction mixture was purified by silica gel column chromatography (Hex:EA=5:1) and solidified with methanol to obtain 33.9 g (yield: 82.8%) of the compound as a white solid (intermediate (1)).

(Synthesis of Intermediate (2))

Intermediate (1) 14.7 g (45.7 mmol), 6-bromo-2-naphthalenol (6-bromo-2-naphthalenol) 10.0 g (44.8 mmol), Pd (PPh ₃ ) ₄ 2.6 in a 2-neck 500 mL flask g (2.2 mmol), K ₂ CO ₃ 13.6 g (98.6 mmol), toluene 120 mL, purified water 50 mL, and ethanol 30 mL were mixed and stirred under reflux for 3 hours. After the reaction was completed, it was cooled to room temperature, purified water was added, and the mixture was extracted with ethyl acetate and the solvent was removed under reduced pressure. The obtained reaction mixture was purified by silica gel column chromatography (Hex:EA=2:1) and solidified with methanol to obtain 9.9 g (yield: 65.2%) of the compound as a white solid (intermediate (2)).

(Synthesis of Intermediate (3))

In a two-necked 500 mL flask, 7.0 g (20.7 mmol) of Intermediate (2), _{5.2 mL (31.1 mmol) of Tf 2} O, 3.5 mL (22.4 mmol) of TEA and 70 mL of dichloromethane were mixed, and then, at room temperature for 2 hours. stirred. After the reaction was completed, purified water was added and extracted, and the solvent was removed under reduced pressure. The reaction mixture was purified by silica gel column chromatography (Hex:EA=2:1) and solidified with methanol to obtain 7.5 g (yield: 77.8%) of the compound as a white solid (intermediate (3)).

intermediate Synthesis example 2: Synthesis of intermediate (6)

(Synthesis of Intermediate (4))

In a 2-neck 2 L flask, 40.0 g (231.2 mmol) of 4-bromophenol, 35.5 g (254.3 mmol) of (4-fluorophenyl) boronic acid, and Pd ( PPh ₃ ) ₄ 13.4 g (11.5 mmol), K ₂ CO ₃ 79.9 g (578.0 mmol), 1,4-dioxane 400 Ml and purified water 160 mL were mixed and stirred under reflux for 4 hours. After the reaction was completed, it was cooled to room temperature, purified water was added, and the mixture was extracted with ethyl acetate and the solvent was removed under reduced pressure. The obtained reaction mixture was purified by silica gel column chromatography (Hex:EA=3:1) and solidified with hexane to obtain 38.8 g (yield: 89.1%) of the compound as a white solid (intermediate (4)).

(Synthesis of Intermediate (5))

_{37.7 g (200.6 mmol) of intermediate (4), 47.3 mL (280.9 mmol) of Tf 2} O, 19.4 mL (240.7 mmol) of pyridine, and 380 mL of dichloromethane were mixed in a 2-neck 500 mL flask, followed by 2 hours while stirring at room temperature. After the reaction was completed, purified water was added and extracted, and the solvent was removed under reduced pressure. The reaction mixture was purified by silica gel column chromatography (Hex:EA=1:1) and solidified with methanol to obtain 36.5 g (yield: 56.8%) of the compound as a white solid (intermediate (5)).

(Synthesis of Intermediate (6))

Intermediate (5) 36.5 g (114.1 mmol), bis(pinacolato)diboron (bis(pinacolato)diboron) 34.8 g (136.9 mmol), Pd(dppf)Cl ₂ -CH ₂ Cl _{2 in a 2-neck 1 L flask} 8.4 g (11.4 mmol), 20.2 g (205.4 mmol) of KOAc, and 360 mL of 1,4-dioxene were mixed and stirred under reflux for 4 hours. After the reaction was completed, it was cooled to room temperature, purified water was added, and the mixture was extracted with ethyl acetate and the solvent was removed under reduced pressure. The obtained reaction mixture was purified by silica gel column chromatography (Hex:EA=4:1) and solidified with methanol to obtain 30.5 g (yield: 89.6%) of the compound (intermediate (6)) as a white solid.

intermediate Synthesis example 3: Synthesis of intermediate (8)

(Synthesis of Intermediate (7))

In a 1-neck 2 L flask, 1-bromo-4-chlorobenzene (1-bromo-4-chlorobenzene) 20.0 g (104.5 mmol), 3,5-bistrifluoromethylphenylboronic acid ((3,5-bis( trifluoromethyl)phenyl)boronic acid) 26.9 g (104.5 mmol), Pd(PPh ₃ ) ₄ 6.0 g (5.2 mmol), K ₂ CO ₃ 36.1 g (261.2 mmol), toluene 500 mL, ethanol 100 mL, and water 100 mL After mixing, the mixture was stirred under reflux for 12 hours. After completion of the reaction, the mixture was cooled to room temperature, added with water, extracted with ethyl acetate, and the solvent was removed under reduced pressure. The obtained reaction mixture was purified by silica gel column chromatography (CHCl ₃ ) and solidified with a mixed solution (DCM/Hex) to obtain 27.3 g (yield: 84.1%) of the compound as a white solid (intermediate (7)).

(Synthesis of Intermediate (8))

5.0 g (15.4 mmol) of intermediate (7), Pd (dba) in a one-necked 250 mL flask 442.8 mg (770.1 μmol), 734.2 mg (1.5 mmol) of X-Phos, 4.5 g (46.2 mmol) of KOAc and 80 mL of toluene were mixed, followed by stirring under reflux for 16 hours. After the reaction was completed, it was cooled to room temperature, purified water was added, and the mixture was extracted with ethyl acetate and the solvent was removed under reduced pressure. The obtained reaction mixture was purified by silica gel column chromatography (Toluene:Hex=1:2) to obtain 4.61 g (yield: 71.9%) of the compound (intermediate (8)) as a white solid.

intermediate Synthesis example 4: Synthesis of intermediate (9)

(Synthesis of Intermediate (9))

In a 1-neck 2 L flask, 4-bromo-biphenyl-4-carbonitrile ((4'-bromo-[1,1'-biphenyl]-4-carbonitrile)) 5.0 g (193.7 mol), pinacoldiboron (Bis(pinacolato)diboron) 73.8 g (290.6 mmol), Pd(dppf)Cl ₂ -CH ₂ Cl ₂ 3.2 g (3.9 mmol), KOAc 57.0 g (581.1 mmol) and 650 mL of Dioxane were mixed for 16 hours. It was stirred at reflux. After the reaction was completed, it was cooled to room temperature, and the reaction product was passed through a celite pad and concentrated under reduced pressure. The reaction mixture was purified by silica gel column chromatography (CHCl ₃ ) and solidified with a mixed solution (DCM/MeOH) to obtain 51.1 g (yield: 86.4%) of the compound (intermediate (9)) as a white solid.

intermediate Synthesis example 5: Synthesis of intermediate (11)

(Synthesis of Intermediate (10))

In a 1-neck 1 L flask, 10.0 g (52.2 mmol) of 1-bromo-4-chlorobenzene, 4-trimethylsilylphenylboronic acid ((4-(trimethylsilyl)phenyl)boronic acid) 10.1 g (52.2 mmol), Pd(PPh ₃ ) ₄ 3.0 g (2.6 mmol), K ₂ CO ₃ 21.7 g (156.7 mmol), toluene 160 mL, ethanol 40 mL, and water 40 mL were mixed for 12 hours. while stirring at reflux. After completion of the reaction, the mixture was cooled to room temperature, added with water, extracted with chloroform, and the solvent was removed under reduced pressure. The obtained reaction mixture was purified by silica gel column chromatography (Hex:CHCl ₃ = 10:1) and solidified with methanol to obtain 9.8 g (yield: 71.9%) of the compound (intermediate (10)) as a white solid.

(Synthesis of intermediate (11))

Intermediate (10) 6.0 g (23.0 mmol), pinacol diboron (Bis(pinacolato)diboron) 8.8 g (34.5 mmol), Pd (dba) in a 1-neck 250 mL flask 1.3 g (2.3 mmol), 2.2 g (4.6 mmol) of X-Phos, 6.8 g (69.0 mmol) of KOAc, and 115 mL of toluene were mixed and stirred under reflux for 12 hours. After the reaction was completed, it was cooled to room temperature, and the reaction product was passed through a celite pad and concentrated under reduced pressure. The reaction mixture was purified by silica gel column chromatography (CHCl ₃ :EA=10:1) and solidified with a mixed solution (DCM/MeOH) to obtain 6.9 g of a white solid compound (intermediate (11)) (yield: 85.1%). got it

intermediate Synthesis example 6: Synthesis of intermediate (13)

(Synthesis of Intermediate (12))

In a 1-neck 2 L flask, 13.7 g (108.1 mmol) of 2-amino-5-fluorophenol and 20.0 g (108.1 mmol) of 4-bromobenzaldehyde were mixed with ethanol. After mixing in 540 mL, the mixture was stirred at 70° C. for 12 hours. After completion of the reaction, the mixture was cooled to room temperature, and the reaction mixture was distilled under reduced pressure to obtain 31.8 g (crude) of a brown solid compound (intermediate (12)).

(Synthesis of Intermediate (13))

In a 1-neck 2 L flask, 31.8 g (108.1 mmol) of the intermediate (12) was dissolved in 540 mL of dichloromethane (DCM). After adding 43.9 g (129.7 mmol) of DDQ. The mixture was stirred at room temperature for 12 hours. The reaction mixture _{was filtered through a pad of celite (CHCl 3} ) and solidified with a mixed solution (DCM/EtOH) to obtain 24.2 g (yield: 76.7%) of the compound as a yellow solid (intermediate (13)).

intermediate Synthesis example 7: Synthesis of intermediate (15)

(Synthesis of Intermediate (14))

In a 1-neck 1 L flask, 10.0 g (56.5 mmol) of 2-amino-5-trifluorophenol (2-amino-5- (trifluoromethyl)phenol) and 10.5 g (56.5 of 4-bromobenzaldehyde) mmol) was mixed with 250 mL of ethanol, and then stirred at 70° C. for 12 hours. After completion of the reaction, it was cooled to room temperature, and the reaction mixture was distilled under reduced pressure to obtain 19.4 g (crude) of the compound (intermediate (14)) as a brown solid.

(Synthesis of Intermediate (15))

In a 1-neck 1 L flask, 19.4 g (56.4 mmol) of the intermediate (14) was dissolved in 250 mL of dichloromethane (DCM). After adding 15.4 g (67.7 mmol) of DDQ. The mixture was stirred at room temperature for 12 hours. The reaction mixture _{was filtered through a pad of celite (CHCl 3} ) and solidified with a mixed solution (DCM/EtOH) to obtain 15.3 g (yield: 79.3%) of the compound (intermediate (15)) as a yellow solid.

intermediate Synthesis example 8: Synthesis of intermediate (17)

(Synthesis of Intermediate (16))

Dissolve 100.0 g (507.5 mmol) of 4-amino-3-bromobenzonitrile in 800 mL of NMP in a 2-neck 2 L flask. After diluting 117.0 g (532.9 mmol) of 4-bromobenzoyl chloride in 200 mL of NMP, it was slowly added dropwise at room temperature and reacted for 12 hours. 500 mL of water was added, and when a solid was precipitated, it was filtered and washed with water and methanol to obtain 177.7 g of a white solid compound (intermediate (16)) (yield: 92.1%).

(Synthesis of intermediate (17))

Intermediate (16) 181.8 g (478.4 mmol), Cu 15.2 g (239.2 mmol), K ₂ CO ₃ 132.2 g (956.8 mmol), Na ₂ SO ₄ 135.9 g (956.8 mmol) and nitrobenzene in a 1-neck 3 L flask 1.5 L was mixed and stirred at reflux for 2 days. After completion of the reaction, the mixture was passed through a celite pad, concentrated under reduced pressure, and solidified with a mixed solution (DCM/MeOH) to obtain 119.0 g of a yellow solid compound (Intermediate (17)) (yield: 83.2%).

intermediate Synthesis example 9: Synthesis of intermediate (19)

(Synthesis of Intermediate (18))

1,3-dibromo-5-chlorobenzene (1,3-dibromo-5-chlorobenzene) 15.0 g (55.4 mmol), (3,5-bis (trifluoromethyl) phenyl) in a 2-neck 1 L flask Boronic acid ((3,5-bis(trifluoromethyl)phenyl)boronic acid) 30.0 g (116.5 mmol), Pd(PPh ₃ ) ₄ 6.4 g (5.5 mmol), K ₂ CO ₃ 23.0 g (166.4 mmol), toluene 180 mL, 100 mL of purified water, and 90 mL of ethanol were mixed and stirred under reflux for 5 hours. After the reaction was completed, it was cooled to room temperature, purified water was added, and the mixture was extracted with ethyl acetate and the solvent was removed under reduced pressure. The obtained reaction mixture was purified by silica gel column chromatography (Hex:DCM=1:1) and solidified with methanol to obtain 16.2 g (yield: 55.1%) of the compound as a white solid (intermediate (18)).

(Synthesis of Intermediate (19))

Intermediate (18) 6.0 g (11.1 mmol), bis (pinacolato) diboron (bis (pinacolato) diboron) 4.3 g (16.7 mmol), Pd (dba) _{2 in a 2-neck 250 mL flask} 600.0 mg (0.1 mmol), 1.1 g (0.2 mmol) of X-Phos, 3.3 g (33.5 mmol) of KOAc and 72 mL of toluene were mixed and stirred under reflux for 6 hours. After the reaction was completed, it was cooled to room temperature, purified water was added, and the mixture was extracted with ethyl acetate and the solvent was removed under reduced pressure. The obtained reaction mixture was purified by silica gel column chromatography (Hex:DCM=1:1) and solidified with methanol to obtain 3.5 g (yield: 49.7%) of the compound as a white solid (intermediate (19)).

intermediate Synthesis example 10: Synthesis of intermediate (20)

In a 1-neck 500 mL flask, 20.0 g (181.6 mmol) of 2-aminopyridin-3-ol and 45.0 g (181.6 mmol) of 4-iodobenzoic acid were added. After mixing well, _{140 mL of POCl 3} was slowly and carefully added at 0° C. and stirred. After raising the temperature to 90 °C, the reaction was carried out for 12 hours. After the reaction was completed, it was cooled to room temperature, and the reactant was slowly added dropwise to ice. After neutralization with Na ₂ CO ₃ aqueous solution, the solid was filtered, washed with water and methanol, and dried to obtain 43.0 g (yield: 73.5%) of the compound as a white solid (intermediate (20)).

intermediate Synthesis example 11: Synthesis of intermediate (22)

(Synthesis of Intermediate (21))

In a 1-neck 2 L flask, 20.0 g (183.3 mmol) of 2-aminophenol and 34.1 g (183.3 mmol) of 6-bromopicolinaldehyde were mixed in 900 mL of ethanol, and then at 70°C. was stirred for 12 hours. After completion of the reaction, the mixture was cooled to room temperature, and the reaction mixture was distilled under reduced pressure to obtain 50.8 g (crude) of the compound as a brown solid (intermediate (21)).

(Synthesis of Intermediate (22))

In a 1-neck 2 L flask, 50.8 g (183.3 mmol) of the intermediate (21) was dissolved in 900 mL of dichloromethane (DCM). After adding 49.9 g (220.0 mmol) of DDQ. The mixture was stirred at room temperature for 12 hours. The reaction mixture was _{filtered through a pad of Celite (CHCl 3} ) and solidified with a mixed solution (DCM/EtOH) to obtain 42.0 g (yield: 83.3%) of the compound (intermediate (22)) as a yellow solid.

intermediate Synthesis example 12: Synthesis of intermediate (24)

(Synthesis of intermediate (23))

In a 1-neck 2 L flask, 17.6 g (161.3 mmol) of 2-aminophenol and 30.0 g (161.3 mmol) of 5-bromopicolinaldehyde were mixed with 800 mL of ethanol in 800 mL of ethanol, and then at 70°C. was stirred for 12 hours. After completion of the reaction, the reaction mixture was cooled to room temperature, and the reaction mixture was distilled under reduced pressure to obtain 45.0 g (crude) of the compound (intermediate (23)) as a brown solid.

(Synthesis of Intermediate (24))

In a 1-neck 2 L flask, 45.0 g (161.3 mmol) of the intermediate (23) was dissolved in 800 mL of dichloromethane. After adding 43.9 g (193.5 mmol) of DDQ. Stirred at 40° C. for 12 hours. The reaction mixture _{was filtered through celite (CHCl 3} ) and solidified with a mixed solution (DCM/EtOH) to obtain 36.2 g (yield: 81.6%) of a pink solid compound (intermediate (24)).

intermediate Synthesis example 13: Synthesis of intermediate (26)

(Synthesis of Intermediate (25))

In a 1-neck 250 mL flask, 3-bromo-7-iodoquinoline (3-bromo-7-iodoquinoline) 5.0 g (15.0 mmol), Intermediate (8) 6.2 g (15.0 mmol), Pd (PPh ₃ ) ₄ 519.0 mg (449.2 μmol), K ₂ CO ₃ 5.2 g (37.4 mmol), toluene 40 mL, ethanol 15 mL and water 15 mL were mixed and stirred under reflux for 5 hours. After completion of the reaction, the mixture was cooled to room temperature, added with water, extracted with chloroform, and the solvent was removed under reduced pressure. The obtained mixture was purified by silica gel column chromatography (CHCl ₃ ). The obtained compound was solidified with a mixed solution (DCM/EtOH) to obtain 3.8 g (yield: 51.1%) of the compound as a pale yellow solid (Intermediate (25)).

(Synthesis of Intermediate (26))

In a one-necked 250 mL flask, 3.8 g (7.7 mmol) of intermediate (25), 2.9 g (11.5 mmol) of pinacol diboron (Bis(pinacolato)diboron), Pd(dppf)Cl ₂ -CH ₂ Cl ₂ 125.0 mg (153.2) μmol), KOAc 2.3 g (23.0 mmol) and 1,4-dioxane 40 mL were mixed, and then stirred at 100° C. for 5 hours. After the reaction was completed, it was cooled to room temperature, and the reaction product was passed through a celite pad and concentrated under reduced pressure. The reaction mixture was purified by silica gel column chromatography (CHCl ₃ :EA=10:1) and solidified with a mixed solution (DCM/MeOH) to obtain 4.0 g (yield: 96.1%) of the compound as a white solid (intermediate (26)). .

intermediate Synthesis example 14: Synthesis of intermediate (27)

(Synthesis of intermediate (27))

In a 1-neck 250 mL flask, 6-bromo-2-iodoquinoxaline (6-bromo-2-iodoquinoxaline) 5.2 g (15.6 mmol), Intermediate (1) 5.0 g (15.6 mmol), Pd (PPh ₃ ) ₄ 540.0 mg (467.0 μmol), K ₂ CO ₃ 6.5 g (46.7 mmol), toluene 40 mL, ethanol 15 mL, and water 15 mL were mixed and stirred under reflux for 5 hours. After completion of the reaction, the mixture was cooled to room temperature, added with water, extracted with chloroform, and the solvent was removed under reduced pressure. The obtained mixture was purified by silica gel column chromatography (CHCl ₃ :EA=10:1). The obtained compound was solidified with a mixed solution (DCM/EtOH) to obtain 4.2 g (yield: 67.1%) of the compound as a pale yellow solid (Intermediate (27)).

intermediate Synthesis example 15: Synthesis of intermediate (29)

(Synthesis of Intermediate (28))

2-bromo-4'-iodo-biphenyl (4-bromo-4'-iodo-biphenyl) 20.0 g (55.7 mmol), 3,5-bis (trifluoromethyl) phenylboronic acid in a 1-neck 1 L flask ((3,5-bis(trifluoromethyl)phenyl)boronic acid) 14.3 g (55.7 mmol), Pd(PPh ₃ ) ₄ 1.9 g (1.6 mmol), K ₂ CO ₃ 19.2 g (138.9 mmol), toluene 300 mL, After mixing 150 mL of ethanol and 150 mL of water, the mixture was stirred under reflux for 15 hours. After completion of the reaction, the mixture was cooled to room temperature, added with water, extracted with dichloromethane, and the solvent was removed under reduced pressure. The reaction mixture thus obtained was purified by silica gel column chromatography (Hex:DCM=10:1) and solidified with methanol to obtain 17.1 g (yield: 68.9%) of the compound (intermediate (28)) as an orange solid.

(Synthesis of Intermediate (29))

In a 1-neck 500 mL flask, 10.0 g (22.5 mmol) of intermediate (28), 11.4 g (44.9 mmol) of pinacol diboron (Bis(pinacolato)diboron), Pd(dppf)Cl ₂ -CH ₂ Cl ₂ 550.0 mg (6.7 mmol), 4.4 g (44.9 mmol) of KOAc and 300 mL of Dioxane were mixed and stirred under reflux for 16 hours. After the reaction was completed, it was cooled to room temperature, and the reaction product was passed through a celite pad and concentrated under reduced pressure. The reaction mixture was purified by silica gel column chromatography (DCM) and solidified with methanol to obtain 9.6 g (yield: 87.1%) of the compound (intermediate (29)) as a white solid.

intermediate Synthesis example 16: Synthesis of intermediate (30)

(Synthesis of intermediate (30))

In a 1-neck 1 L flask, 1-bromo-3,5-bistrifluoromethylbenzene (1-bromo-3,5-bis(trifluoromethyl)benzen 17.0 g (58.1 mmol), 4-chloronaphthalen-1-yl Boronic acid (4-chloronaphthalen-1-yl)boronic acid) 10.0 g (48.4 mmol), Pd (PPh ₃ ) ₄ 2.8 g (2.4 mmol), K ₂ CO ₃ 20.1 g (145.3 mmol), 160 mL toluene, After mixing 40 mL of ethanol and 40 mL of water, the mixture was stirred under reflux for 12 hours. After completion of the reaction, the mixture was cooled to room temperature, added with water, extracted with chloroform, and the solvent was removed under reduced pressure. The obtained reaction mixture was purified by silica gel column chromatography (Hex:CHCl ₃ = 10:1) and solidified with methanol to obtain 11.5 g (yield: 63.4%) of the compound as a white solid (intermediate (30)).

intermediate Synthesis example 17: Synthesis of intermediate (31)

(Synthesis of intermediate (31))

Intermediate (3) 6.0 g (12.8 mmol), pinacol diboron (Bis(pinacolato)diboron) 4.9 g (19.2 mmol), Pd (dba) in a 1-neck 250 mL flask 735.0 mg (1.3 mmol), 1.2 g (2.6 mmol) of X-Phos, 3.8 g (38.3 mmol) of KOAc and 65 mL of toluene were mixed and stirred under reflux for 5 hours. After the reaction was completed, it was cooled to room temperature, and the reaction product was passed through a celite pad and concentrated under reduced pressure. The reaction mixture was purified by silica gel column chromatography (CHCl ₃ :EA=10:1) and solidified with a mixed solution (DCM/MeOH) to obtain 4.4 g (yield: 76.6%) of the compound as a white solid (intermediate (31)). .

intermediate Synthesis example 18: Synthesis of intermediate (34)

(Synthesis of Intermediate (32))

In a 1-neck 2 L flask, 50.0 g (224.2 mmol) of 7-bromonaphthalen-2-ol, 3,5-bistrifluoromethylphenylboronic acid ((3,5-bis (trifluoromethyl)phenyl)boronic acid) 57.8 g (224.2 mmol), Pd(PPh3) ₄ 7.8 g (6.7 mmol), K ₃ PO ₄ 142.7 g (672.5 mmol), toluene 500 mL, ethanol 150 mL, and water 150 mL After mixing, the mixture was stirred under reflux for 12 hours. After completion of the reaction, the mixture was cooled to room temperature, added with water, extracted with ethyl acetate, and the solvent was removed under reduced pressure. The obtained reaction mixture was purified by silica gel column chromatography (CHCl ₃ →CHCl3:EA=9:1) to obtain 55.2 g (yield: 69.1%) of the compound (intermediate (32)) as a white solid.

(Synthesis of intermediate (33))

In a 1-neck 2 L flask, 55.2 g (154.9 mmol) of the intermediate (32) was dissolved in 600 mL of dichloromethane (DCM), 37.5 mL (464.8 mmol) of pyridine was added dropwise, and the temperature was lowered to 0°C. Tf ₂ O 31.2 mL (185.9 mmol) was slowly added dropwise, and then the temperature was raised to room temperature, followed by reaction for 12 hours. The reaction product was washed with water (500 mL), and the separated organic layer was dried over anhydrous sodium sulfate, filtered, concentrated, and purified by column chromatography (CHCl ₃ ) to form a yellow liquid compound (intermediate (33)) 75.7 g (yield) : 100%) was obtained.

(Synthesis of Intermediate (34))

1 2 Intermediate 33 to L flask, 45.7 g (154.9 mmol), pinacol diboron (Bis (pinacolato) diboron) 59.0 g (232.4 mmol), Pd (dppf) Cl 2 - CH 2 Cl 2 2.5 g (3.1 mmol), 45.6 g (464.8 mmol) of KOAc and 700 mL of 1,4-dioxane were mixed, followed by stirring at 100° C. for 12 hours. After the reaction was completed, it was cooled to room temperature, and the reaction product was passed through a celite pad and concentrated under reduced pressure. The reaction mixture was purified by silica gel column chromatography (CHCl ₃ ) to obtain 61.1 g (yield: 83.2%) of the compound (intermediate (34)) as a gray solid.

intermediate Synthesis example 19: Synthesis of intermediate (35)

(Synthesis of intermediate (35))

2-bromo-7-iodophenanthrene (2-bromo-7-iodophenanthrene)benzen 5.0 g (13.1 mmol), 3,5-bistrifluoromethylphenylboronic acid ((3, 5-bis(trifluoromethyl)phenyl)boronic acid) 3.8 g (13.1 mmol), Pd(PPh ₃ ) ₄ 453.0 mg (391.62 μmol), K ₂ CO ₃ 5.4 g (39.2 mmol), toluene 40 mL, ethanol 15 mL and After mixing 15 mL of water, the mixture was stirred under reflux for 5 hours. After the reaction was completed, it was cooled to room temperature, the solid was filtered, washed with water and ethanol, and dried. The obtained solid mixture was purified by silica gel column chromatography (CHCl ₃ ) and solidified with a mixed solution (DCM/EtOH) to obtain 4.9 g (yield: 80.0%) of the compound as a white solid (intermediate (35)).

intermediate Synthesis example 20: Synthesis of intermediate (37)

(Synthesis of Intermediate (36))

In a 1-neck 500 mL flask, 10.0 g (38.9 mmol) of 9-bromoanthracene, 3,5-bistrifluoromethylphenylboronic acid ((3,5-bis(trifluoromethyl)phenyl)boronic acid) 10.0 g (38.9 mmol), Pd(PPh ₃ ) ₄ 2.3 g (1.9 mmol), K ₂ CO ₃ 13.4 g (97.2 mmol), toluene 120 mL, ethanol 40 mL and water 40 mL were mixed and stirred under reflux for 12 hours. did. After the reaction was completed, it was cooled to room temperature, the solid was filtered, washed with water and ethanol, and dried. The obtained solid mixture was purified by silica gel column chromatography (CHCl ₃ ) and solidified with a mixed solution (DCM/EtOH) to obtain 4.9 g (yield: 80.0%) of the compound as a white solid (intermediate (36)).

(Synthesis of intermediate (37))

After dissolving 4.9 g (12.6 mmol) of the intermediate (36) in 65 mL of DMF in a one-necked 250 mL flask, the temperature was lowered to 0 °C. 2.2 g (12.6 mmol) of N-Bromosuccinimide was added, stirred at 0° C. for 30 minutes, and then reacted at room temperature for 5 hours. After completion of the reaction, water was added and stirred, the solid was filtered, washed with water and methanol, and dried. The obtained solid mixture was purified by silica gel column chromatography (CHCl ₃ ) and solidified with a mixed solution (DCM/EtOH) to obtain 4.1 g (yield: 71.3%) of the compound as a white solid (intermediate (37)).

intermediate Synthesis example 21: Synthesis of intermediate (38)

(Synthesis of Intermediate (38))

2- (4-bromophenyl) benzothiazole (2- (4-bromophenyl) benzothiazole) 10.0 g (34.5 mmol) in a 2-neck 1 L flask, bis (pinacolato) diboron (bis (pinacolato) diboron) 13.1 g (51.7 mmol), Pd (dppf) Cl 2 - CH 2 Cl 2 1.3 g (1.7 mmol), KOAc 10.1 g (103.4 mmol) and 1,4-oksen a mixture of 120 mL and then stirred under reflux for 18 hours did. After the reaction was completed, it was cooled to room temperature, purified water was added, and the mixture was extracted with ethyl acetate and the solvent was removed under reduced pressure. The obtained reaction mixture was purified by silica gel column chromatography (Hex:EA=8:1) and solidified with methanol to obtain 7.2 g (yield: 62.0%) of the compound as a white solid (intermediate (38)).

intermediate Synthesis example 22: Synthesis of intermediate (40)

(Synthesis of intermediate (39))

In a 2-neck 500 mL flask, 15.1 g (44.8 mmol) of intermediate (38), 10.0 g (44.8 mmol) of 6-bromo-2-naphthalenol, Pd (PPh ₃ ) ₄ 2.6 g (2.2 mmol), K ₂ CO ₃ 18.5 g (134.4 mmol), toluene 100 mL, purified water 40 mL, and ethanol 20 mL were mixed and stirred under reflux for 4 hours. After the reaction was completed, it was cooled to room temperature, purified water was added, and the mixture was extracted with ethyl acetate and the solvent was removed under reduced pressure. The obtained reaction mixture was purified by silica gel column chromatography (Hex:EA=2:1) and solidified with methanol to obtain 8.5 g (yield: 53.9%) of the compound as a white solid (intermediate (39)).

(Synthesis of intermediate (40))

In a two-necked 500 mL flask, 8.5 g (24.1 mmol) of intermediate (39), _{6.1 mL (36.2 mmol) of Tf 2} O, 4.4 mL (31.4 mmol) of TEA and 90 mL of dichloromethane were mixed, and then at room temperature for 2 hours. stirred. After the reaction was completed, purified water was added and extracted, and the solvent was removed under reduced pressure. The reaction mixture was purified by silica gel column chromatography (Hex:EA=2:1) and solidified with methanol to obtain 6.1 g (yield: 52.0%) of the compound as a white solid (intermediate (40)).

intermediate Synthesis example 23: Synthesis of intermediate (42)

(Synthesis of intermediate (41))

Intermediate (6) 10.8 g (36.2 mmol), 6-bromo-2-naphthalenol (6-bromo-2-naphthalenol) 8.0 g (35.8 mmol), Pd (PPh ₃ ) ₄ 2.1 in a 2-neck 250 mL flask g (1.8 mmol), K ₂ CO ₃ 14.9 g (107.5 mmol), 96 mL of toluene and 40 mL of purified water were mixed and stirred under reflux for one day. After the reaction was completed, it was cooled to room temperature, purified water was added, and the mixture was extracted with ethyl acetate and the solvent was removed under reduced pressure. The obtained reaction mixture was purified by silica gel column chromatography (Hex:EA=2:1) and solidified with methanol to obtain 3.2 g (yield: 27.9%) of the compound as a white solid (intermediate (41)).

(Synthesis of Intermediate (42))

Intermediate (41) 3.2 g (10.0 mmol), Tf ₂ O 2.1 mL (12.0 mmol), TEA 1.7 mL (12.0 mmol) and dichloromethane 32 mL were mixed in a two-necked 250 mL flask, and then at room temperature for 2 hours. stirred. After the reaction was completed, purified water was added and extracted, and the solvent was removed under reduced pressure. The reaction mixture was purified by silica gel column chromatography (Hex:EA=2:1) and solidified with methanol to obtain 2.9 g (yield: 64.8%) of the compound as a white solid (intermediate (42)).

Various benzazole derivatives were synthesized as follows using the synthesized intermediate compound.

Example 1: Synthesis of compound 3-1 (LT20-35-101)

In a two-necked 250 mL flask, intermediate (3) 3.7 g (8.3 mmol), intermediate (6) 2.5 g (8.3 mmol), Pd(PPh ₃ ) ₄ 500.0 mg (0.5 mmol), K ₂ CO ₃ 2.2 g (16.6 mmol) ), toluene 45 mL, purified water 18 mL, and ethanol 11 mL were mixed, and then stirred under reflux for 4 hours. After the reaction was completed, it was cooled to room temperature, the solid was filtered, washed with water and methanol, and dried. The obtained solid mixture was purified by silica gel column chromatography (CHCl ₃ ) and solidified with methanol to obtain 1.7 g (yield: 45.4%) of compound 3-1 (LT20-35-101) as a white solid.

Example 2: Synthesis of compound 3-6 (LT20-30-114)

Intermediate (3) 3.2 g (7.7 mmol), Intermediate (8) 3.0 g (6.4 mmol), Pd(PPh ₃ ) ₄ 221.5 mg (191.7 μmol), K ₂ CO ₃ 2.7 g (19.2 mmol) in a 1-neck 250 mL flask ), toluene 32 mL, ethanol 8 mL, and water 8 mL were mixed and stirred at 90° C. for 4 hours. After the reaction was completed, it was cooled to room temperature, the solid was filtered, washed with water, methanol, and ethyl acetate, and dried. The obtained solid mixture was purified by silica gel column chromatography (CHCl ₃ ) and solidified with chloroform to obtain 3.0 g (yield: 77.0%) of compound 3-6 (LT20-30-114) as a white solid.

Example 3: Synthesis of compound 3-7 (LT20-35-102)

In a two-necked 250 mL flask, intermediate (3) 3.7 g (7.9 mmol), intermediate (9) 2.4 g (7.9 mmol), Pd(PPh ₃ ) ₄ 500.0 mg (0.4 mmol), K ₂ CO ₃ 2.2 g (15.9 mmol) ), toluene 38 mL, purified water 15 mL, and ethanol 7 mL were mixed and stirred under reflux for 4 hours. After the reaction was completed, it was cooled to room temperature, the solid was filtered, washed with water and methanol, and dried. The obtained solid mixture was purified by silica gel column chromatography (CHCl ₃ ) and solidified with methanol to obtain 2.9 g (yield: 72.6%) of compound 3-7 (LT20-35-102) as a white solid.

Example 4: Synthesis of compound 3-8 (LT20-35-103)

In a two-necked 250 mL flask, intermediate (3) 3.0 g (6.4 mmol), intermediate (11) 2.3 g (6.4 mmol), Pd(PPh ₃ ) ₄ 369.0 mg (319.5 μmol), K ₂ CO ₃ 2.7 g (19.2 mmol) ), toluene 30 mL, purified water 10 mL, and ethanol 10 mL were mixed and stirred under reflux for 12 hours. After the reaction was completed, it was cooled to room temperature, the solid was filtered, washed with water and methanol, and dried. The obtained solid mixture was purified by silica gel column chromatography (CHCl ₃ ) and solidified with a mixed solution (DCM/EtOH) to obtain 2.1 g (yield: 63.1%) of compound 3-8 (LT20-35-103) as a white solid. .

Example 5: Synthesis of compound 3-14 (LT20-35-104)

2.5 g (8.6 mmol) of intermediate (13), 3.6 g (8.6 mmol) of intermediate (8), 495.0 mg (427.9 μmol) of _{Pd(PPh 3} ) ₄ , 2.6 g (25.7 mmol) of K 2 CO _{3 in a 2-neck 250 mL flask} ), toluene 30 mL, purified water 10 mL, and ethanol 10 mL were mixed and stirred under reflux for 12 hours. After the reaction was completed, it was cooled to room temperature, the solid was filtered, washed with water and methanol, and dried. The obtained solid mixture was purified by silica gel column chromatography (CHCl ₃ ) and solidified with a mixed solution (DCM/AcOH) to obtain 3.2 g (yield: 59.6%) of compound 3-14 (LT20-35-104) as a white solid. .

Example 6: Synthesis of compound 3-22 (LT20-35-105)

In a 2-neck 250 mL flask, 2.5 g (7.3 mmol) of intermediate (15), 3.0 g (7.3 mmol) of intermediate (8), 422.0 mg (365.4 μmol) of _{Pd(PPh 3} ) ₄ , 3.0 g (21.9 mmol _{) of K 2} CO ₃ ), toluene 30 mL, purified water 10 mL, and ethanol 10 mL were mixed and stirred under reflux for 12 hours. After the reaction was completed, it was cooled to room temperature, the solid was filtered, washed with water and methanol, and dried. The obtained solid mixture was purified by silica gel column chromatography (CHCl ₃ ) and solidified with a mixed solution (DCM/AcOH) to obtain 3.4 g (yield: 68.7%) of compound 3-22 (LT20-35-105) as a white solid. .

Example 7: Synthesis of compound 3-30 (LT20-35-106)

In a two-necked 250 mL flask, intermediate (17) 2.5 g (8.4 mmol), intermediate (8) 3.5 g (8.4 mmol), Pd(PPh ₃ ) ₄ 483.0 mg (417.9 μmol), K ₂ CO ₃ 3.5 g (25.1 mmol) ), toluene 30 mL, purified water 10 mL, and ethanol 10 mL were mixed and stirred under reflux for 12 hours. After the reaction was completed, it was cooled to room temperature, the solid was filtered, washed with water and methanol, and dried. The obtained solid mixture was purified by silica gel column chromatography (CHCl ₃ ) and solidified with a mixed solution (DCM/AcOH) to obtain 2.9 g (yield: 54.7%) of compound 3-30 (LT20-35-106) as a white solid. .

Example 8: Synthesis of compound 3-33 (LT20-30-110)

2.5 g (5.4 mmol) of intermediate (3), 3.4 g (5.4 mmol) of intermediate (19), 300.0 mg (0.2 mmol) of _{Pd(PPh 3} ) ₄ , 1.5 g (10.8 mmol) of K 2 CO _{3 in a 2-neck 250 mL flask} ), toluene 30 mL, purified water 15 mL, and ethanol 10 mL were mixed and stirred under reflux for 4 hours. After the reaction was completed, it was cooled to room temperature, the solid was filtered, washed with water and methanol, and dried. The obtained solid mixture was purified by silica gel column chromatography (CHCl ₃ ) and solidified with methanol to obtain 3.5 g (yield: 78.3%) of compound 3-33 (LT20-35-110) as a white solid.

Example 9: Synthesis of compound 3-42 (LT20-35-107)

2.5 g (7.8 mmol) of intermediate (20), 3.2 g (7.8 mmol) of intermediate (8), 448.0 mg (388.1 μmol) of _{Pd(PPh 3} ) ₄ , 3.2 g (23.3 mmol) of K 2 CO _{3 in a 2-neck 250 mL flask} ), toluene 30 mL, purified water 10 mL, and ethanol 10 mL were mixed and stirred under reflux for 12 hours. After the reaction was completed, it was cooled to room temperature, the solid was filtered, washed with water and methanol, and dried. The obtained solid mixture was purified by silica gel column chromatography (CHCl ₃ :EA=10:1) and solidified with dichloromethane, 2.8 g of compound 3-42 (LT20-35-107) as a white solid (yield: 59.1%) got

Example 10: Synthesis of compound 3-50 (LT20-35-108)

In a 2-neck 250 mL flask, intermediate (22) 2.0 g (7.3 mmol), intermediate (8) 3.0 g (7.3 mmol), Pd(PPh ₃ ) ₄ 420.0 mg (363.5 μmol), K ₂ CO ₃ 3.0 g (21.8 mmol) ), toluene 30 mL, purified water 10 mL, and ethanol 10 mL were mixed and stirred under reflux for 12 hours. After the reaction was completed, it was cooled to room temperature, the solid was filtered, washed with water and methanol, and dried. The obtained solid mixture was purified by silica gel column chromatography (CHCl ₃ :EA=10:1) and solidified with dichloromethane, 1.9 g of compound 3-50 (LT20-35-108) as a white solid (yield: 42.8%) got

Example 11: Synthesis of compound 3-58 (LT20-35-109)

In a 2-neck 250 mL flask, intermediate (24) 2.0 g (7.3 mmol), intermediate (8) 3.0 g (7.3 mmol), Pd(PPh ₃ ) ₄ 420.0 mg (363.5 μmol), K ₂ CO ₃ 3.0 g (21.8 mmol) ), toluene 30 mL, purified water 10 mL, and ethanol 10 mL were mixed and stirred under reflux for 12 hours. After the reaction was completed, it was cooled to room temperature, the solid was filtered, washed with water and methanol, and dried. The obtained solid mixture was purified by silica gel column chromatography (CHCl ₃ :EA=10:1) and solidified with dichloromethane, 2.1 g of compound 3-58 (LT20-35-109) as a white solid (yield: 47.3%) got

Example 12: Synthesis of compound 3-66 (LT20-35-110)

In a 2-neck 250 mL flask, 2- (4-bromophenylbenzoxazole) (2- (4-bromophenyl) benzo [d] oxazole) 2.0 g (7.3 mmol), Intermediate (26) 4.0 g (7.3 mmol), Pd(PPh ₃ ) ₄ 422.0 mg (364.8 μmol), K ₂ CO ₃ 3.0 g (21.9 mmol), toluene 30 mL, purified water 10 mL, and ethanol 10 mL were mixed and stirred under reflux for 12 hours. After the reaction was completed, it was cooled to room temperature, the solid was filtered, washed with water and methanol, and dried. The obtained solid mixture was purified by silica gel column chromatography (CHCl ₃ :EA=10:1) and solidified with dichloromethane, 2.2 g of compound 3-66 (LT20-35-110) as a white solid (yield: 49.4%) got

Example 13: Synthesis of compound 3-74 (LT20-35-111)

In a two-necked 250 mL flask, 2.8 g (7.0 mmol) of intermediate (27), 2.9 g (7.0 mmol) of intermediate (8), 402.0 mg (348.0 μmol) of _{Pd(PPh 3} ) ₄ , 2.9 g (20.9 mmol _{) of K 2} CO ₃ ), toluene 30 mL, purified water 10 mL, and ethanol 10 mL were mixed and stirred under reflux for 12 hours. After the reaction was completed, it was cooled to room temperature, the solid was filtered, washed with water and methanol, and dried. The obtained solid mixture was purified by silica gel column chromatography (CHCl ₃ :EA=5:1) and solidified with chloroform to obtain 1.6 g (yield: 37.6%) of compound 3-74 (LT20-35-111) as a white solid. .

Example 14: Synthesis of compound 3-82 (LT20-35-112)

Intermediate (3) 3.0 g (6.4 mmol), intermediate (29) 3.1 g (6.4 mmol), Pd(PPh ₃ ) ₄ 221.5 mg (191.6 μmol), K ₂ CO ₃ 2.2 g (15.9 mmol), toluene 100 mL, After mixing 50 mL of ethanol and 50 mL of water, the mixture was stirred under reflux for 15 hours. After the reaction was completed, it was cooled to room temperature, the solid was filtered, washed with water and methanol, and dried. The obtained solid mixture was purified by silica gel/Cellike pad and solidified with dichloromethane to obtain 1.3 g (yield: 30.6%) of compound 3-82 (LT20-35-112) as a white solid.

Example 15: Synthesis of compound 3-90 (LT20-30-122)

Intermediate (31) 3.0 g (6.7 mmol), Intermediate (30) 2.6 g (7.0 mmol), Pd (dba) 385.6 mg (670.6 μmol), 639.4 mg (1.3 mmol) of X-Phos, _{4.3 g (20.1 mmol) of K 3} PO ₄ and 35 mL of xylene were mixed and stirred under reflux for 12 hours. After the reaction was completed, it was cooled to room temperature, the solid was filtered, washed with water and methanol, and dried. The obtained solid mixture was purified by silica gel column chromatography (CHCl ₃ ) and solidified with a mixed solution (DCM/Acetone) to obtain 1.7 g (yield: 39.3%) of compound 3-90 (LT20-30-122) as a white solid. .

Example 16: Synthesis of compound 3-98 (LT20-35-113)

3.0 g (6.7 mmol) of intermediate (31), 3.3 g (7.0 mmol) of intermediate (33), Pd (dba) 385.6 mg (670.6 μmol), 639.4 mg (1.3 mmol) of X-Phos, _{4.3 g (20.1 mmol) of K 3} PO ₄ and 35 mL of xylene were mixed and stirred under reflux for 12 hours. After the reaction was completed, it was cooled to room temperature, the solid was filtered, washed with water and methanol, and dried. The obtained solid mixture was purified by silica gel column chromatography (CHCl ₃ ) and solidified with dichloromethane to obtain 2.3 g (yield: 52.0%) of compound 3-98 (LT20-35-113) as a white solid.

Example 17: Synthesis of compound 3-106 (LT20-35-114)

Intermediate (31) 2.8 g (6.3 mmol), intermediate (35) 2.9 g (6.3 mmol), Pd(PPh ₃ ) ₄ 361.0 mg (313.0 μmol), K ₂ CO ₃ 2.6 g (18.8 mmol), toluene 30 mL, After mixing 10 mL of ethanol and 10 mL of water, the mixture was stirred under reflux for 15 hours. After the reaction was completed, it was cooled to room temperature, the solid was filtered, washed with water and methanol, and dried. The obtained solid mixture was purified by silica gel column chromatography (CHCl ₃ ) and then solidified with dichloromethane to obtain 1.9 g (yield: 42.8%) of compound 3-106 (LT20-35-114) as a white solid.

Example 18: Synthesis of compound 3-122 (LT20-35-115)

Intermediate (31) 2.8 g (6.3 mmol), intermediate (37) 2.9 g (6.3 mmol), Pd(PPh ₃ ) ₄ 361.0 mg (313.0 μmol), K ₂ CO ₃ 2.6 g (18.8 mmol), toluene 30 mL, After mixing 10 mL of ethanol and 10 mL of water, the mixture was stirred under reflux for 15 hours. After the reaction was completed, it was cooled to room temperature, the solid was filtered, washed with water and methanol, and dried. The obtained solid mixture was purified by silica gel column chromatography (CHCl ₃ ) and then solidified with dichloromethane to obtain 2.4 g (yield: 54.0%) of compound 3-122 (LT20-35-115) as a white solid.

Example 19: Synthesis of compound 4-1 (LT20-35-116)

In a two-necked 250 mL flask, intermediate (38) 2.2 g (6.4 mmol), intermediate (42) 2.9 g (6.4 mmol), Pd(PPh ₃ ) ₄ 400.0 mg (0.3 mmol), K ₂ CO ₃ 1.8 g (12.9 mmol) ), 29 mL of toluene, and 12 mL of purified water were mixed and stirred under reflux for 3 hours. After the reaction was completed, it was cooled to room temperature, the solid was filtered, washed with water and methanol, and dried. The obtained solid mixture was purified by silica gel column chromatography (CHCl ₃ ) and solidified with methanol to obtain 2.1 g (yield: 64.0%) of compound 4-1 (LT20-35-116) as a white solid.

Example 20: Synthesis of compound 4-6 (LT20-35-117)

In a 2-neck 250 mL flask, intermediate (40) 3.5 g (7.2 mmol), intermediate (8) 3.0 g (7.2 mmol), Pd(PPh ₃ ) ₄ 416.5 mg (360.5 μmol), K ₂ CO ₃ 3.0 g (21.6 mmol) ), toluene 30 mL, purified water 10 mL, and ethanol 10 mL were mixed and stirred under reflux for 12 hours. After the reaction was completed, it was cooled to room temperature, the solid was filtered, washed with water and methanol, and dried. The obtained solid mixture was purified by silica gel column chromatography (CHCl ₃ :EA=10:1) and solidified with dichloromethane, 1.8 g of compound 4-6 (LT20-35-117) as a white solid (yield: 39.9%) got

Example 21: Synthesis of compound 4-7 (LT20-35-118)

In a two-necked 250 mL flask, 5.0 g (10.3 mmol) of intermediate (40), 3.1 g (10.3 mmol) of intermediate (9), 600.0 mg (0.5 mmol) of _{Pd(PPh 3} ) ₄ , 2.9 g (20.6 mmol _{) of K 2} CO ₃ ), toluene 60 mL, purified water 30 mL, and ethanol 20 mL were mixed and stirred under reflux for 5 hours. After the reaction was completed, it was cooled to room temperature, the solid was filtered, washed with water and methanol, and dried. The obtained solid mixture was purified by silica gel column chromatography (CHCl ₃ ) and solidified with methanol to obtain 3.6 g (yield: 68.8%) of compound 4-7 (LT20-35-118) as a white solid.

Example 22: Synthesis of compound 4-98 (LT20-35-119)

In a 2-neck 250 mL flask, intermediate (40) 3.5 g (7.2 mmol), intermediate (34) 3.4 g (7.2 mmol), Pd(PPh ₃ ) ₄ 416.5 mg (360.5 μmol), K ₂ CO ₃ 3.0 g (21.6 mmol) ), toluene 30 mL, purified water 10 mL, and ethanol 10 mL were mixed and stirred under reflux for 12 hours. After the reaction was completed, it was cooled to room temperature, the solid was filtered, washed with water and methanol, and dried. The obtained solid mixture was purified by silica gel column chromatography (CHCl ₃ :EA=10:1) and solidified with dichloromethane, 2.1 g of compound 4-98 (LT20-35-119) as a white solid (yield: 43.1%) got

<Test Example>

For compounds of the present invention J.A. The n (refractive index) and k (extinction coefficient) of the single film for optical property evaluation were measured using WOOLLAM's Ellipsometer instrument.

Fabrication of single film for evaluation of optical properties:

To measure the optical properties of the compound, a glass substrate (0.7T) was washed in Ethanol, DI Water, and Acetone for 10 minutes each, ^{and then treated with oxygen plasma at 2×10 - 2} Torr at 125 W for 2 minutes, and 9×10 ^{- A single} film is fabricated by depositing 800 Å of the compound on a glass substrate at a rate of 1 Å/sec in a vacuum of 7 Torr.

Comparative test example:

_{Alq 3} and REF01 were used as compounds in the production of the single film for evaluation of optical properties, respectively.

< Test Examples 1-22 >

Each compound shown in Table 1 below was used as a compound in the production of the single film for evaluation of optical properties, respectively.

The optical properties of the compounds according to the Comparative Test Examples and Test Examples 1 to 22 are shown in Table 1.

The optical properties are refractive index constants at 460 nm and 620 nm wavelengths.

division compound n (460 nm) n (620 nm) Comparative test example 1 Alq ₃ 1.808 1.690 Comparative test example 2 REF01 1.986 1.846 Test Example 1 3-1
(LT20-35-101) 1.468 1.443 Test Example 2 3-6
(LT20-30-114) 1.440 1.427 Test Example 3 3-7
(LT20-35-102) 1.714 1.637 Test Example 4 3-8
(LT20-35-103) 1.470 1.444 Test Example 5 3-14
(LT20-35-104) 1.432 1.425 Test Example 6 3-22
(LT20-35-105) 1.428 1.414 Test Example 7 3-30
(LT20-35-106) 1.592 1.572 Test Example 8 3-33
(LT20-30-110) 1.692 1.651 Test Example 9 3-42
(LT20-35-107) 1.446 1.439 Test Example 10 3-50
(LT20-35-108) 1.440 1.431 Test Example 11 3-58
(LT20-35-109) 1.441 1.435 Test Example 12 3-66
(LT20-35-110) 1.468 1.443 Test Example 13 3-74
(LT20-35-111) 1.474 1.449 Test Example 14 3-82
(LT20-35-112) 1.459 1.441 Test Example 15 3-90
(LT20-30-122) 1.579 1.537 Test Example 16 3-98
(LT20-35-113) 1.692 1.675 Test Example 17 3-106
(LT20-35-114) 1.714 1.637 Test Example 18 3-122
(LT20-35-115) 1.758 1.668 Test Example 19 4-1
(LT20-35-116) 1.474 1.449 Test Example 20 4-6
(LT20-35-117) 1.440 1.431 Test Example 21 4-7
(LT20-35-118) 1.692 1.651 Test Example 22 4-98
(LT20-35-119) 1.474 1.449

As can be seen from Table 1, the n values in the blue region (460 nm) and the red region (620 nm) of the _{comparative test example (Alq 3 ) were 1.808 and 1.690, respectively, whereas most of the compounds according to the present invention were} In general, it was confirmed to have a lower refractive index (n<1.69 @620nm) than the _{comparative test example compound (Alq 3} ) in the blue region, the green region and the red region. This satisfies the low refractive index value required to secure a high viewing angle in the blue region.

<Example>

device fabrication

For device fabrication, ITO, a transparent electrode, was used as the anode layer, 2-TNATA was a hole injection layer, NPB was a hole transport layer, αβ-ADN was a host of the light emitting layer, Pyrene-CN was a blue fluorescent dopant, and Alq ₃ was an electron transport layer. , Liq was used as an electron injection layer, and Mg:Ag was used as a cathode. The structures of these compounds are as follows.

Comparative Example 1 (without capping layer): ITO / 2-TNATA (60 nm) / NPB (20 nm) / αβ-ADN: 10% Pyrene-CN (30 nm) / Alq ₃ (30 nm) / Liq ( 2 nm) / Mg:Ag (1:9, 10 nm)

Comparative Example 2 (Capping layer consists of one layer): ITO / 2-TNATA (60 nm) / NPB (20 nm) / αβ-ADN: 10% Pyrene-CN (30 nm) / Alq ₃ (30 nm) / Liq (2 nm) / Mg:Ag (1:9, 10 nm) /Alq ₃ (80 nm)

Example (Capping layer consists of two layers): ITO / 2-TNATA (60 nm) / NPB (20 nm) / αβ-ADN: 10% Pyrene-CN (30 nm) / Alq ₃ (30 nm) / Liq (2 nm) / Mg:Ag (1:9, 10 nm) / compound of the present invention (20 nm, low refractive compound) / REF01 (60 nm, high refractive compound)

Blue fluorescence organic light emitting device is ITO (180 nm) / 2-TNATA (60 nm) / NPB (20 nm) / αβ-ADN:Pyrene-CN 10% (30 nm) / Alq ₃ (30 nm) / Liq (2 nm) / Mg:Ag (1:9, 10 nm) / capping layer was deposited in the order to fabricate a device.

Before depositing the organic material, the ITO electrode was ^{subjected to oxygen plasma treatment at 2 × 10 - 2} Torr at 125 W for 2 minutes. The organic material was ^{deposited at a vacuum of 9 × 10 - 7} Torr, Liq was 0.1 Å/sec, αβ-ADN was 0.18 Å/sec, and Pyrene-CN was simultaneously deposited at 0.02 Å/sec, and the remaining organic materials were all 1 Deposited at a rate of Å/sec.

After the device was fabricated, it was encapsulated in a glove box filled with nitrogen gas to prevent the device from contacting air and moisture. After forming the barrier with 3M's adhesive tape, barium oxide, a moisture absorbent that can remove moisture, was added and a glass plate was attached.

< Examples 1-22 >

In the above embodiment, as a capping layer, a multi-layer having a high refractive layer (60 nm) formed on a low refractive layer (20 nm), REF01 compound in the high refractive layer, and each compound shown in Table 2 below in the low refractive layer was used except that fabricated the device in the same manner as in Example 1.

Table 2 shows the electroluminescence characteristics of the organic light emitting diodes prepared in Comparative Examples 1, 2, and 1 to 22.

division compound drive voltage
[V] efficiency
[cd/A] life span
(%) Comparative Example 1 - 4.51 4.22 89.21 Comparative Example 2 Alq ₃ Sole 4.50 4.83 88.92 Example 1 3-1
(LT20-35-101) 4.42 6.11 97.54 Example 2 3-6
(LT20-30-114) 4.47 6.32 98.13 Example 3 3-7
(LT20-35-102) 4.49 5.53 95.61 Example 4 3-8
(LT20-35-103) 4.41 6.23 97.55 Example 5 3-14
(LT20-35-104) 4.40 6.25 97.42 Example 6 3-22
(LT20-35-105) 4.42 6.65 98.00 Example 7 3-30
(LT20-35-106) 4.40 5.81 97.32 Example 8 3-33
(LT20-30-110) 4.49 5.43 95.55 Example 9 3-42
(LT20-35-107) 4.40 6.25 97.42 Example 10 3-50
(LT20-35-108) 4.41 6.23 97.55 Example 11 3-58
(LT20-35-109) 4.50 6.22 95.67 Example 12 3-66
(LT20-35-110) 4.45 6.13 97.45 Example 13 3-74
(LT20-35-111) 4.40 6.00 98.11 Example 14 3-82
(LT20-35-112) 4.42 6.11 97.54 Example 15 3-90
(LT20-30-122) 4.40 5.81 97.32 Example 16 3-98
(LT20-35-113) 4.49 5.53 95.61 Example 17 3-106
(LT20-35-114) 4.49 5.43 95.55 Example 18 3-122
(LT20-35-115) 4.51 5.31 95.61 Example 19 4-1
(LT20-35-116) 4.41 6.23 97.55 Example 20 4-6
(LT20-35-117) 4.47 6.32 98.13 Example 21 4-7
(LT20-35-118) 4.49 5.53 95.61 Example 22 4-98
(LT20-35-119) 4.41 6.23 97.55

As can be seen from the results of Table 2, when looking at the results of the device (Comparative Example 2) and the device without (Comparative Example 1) with the capping layer (Capping Layer, light efficiency improvement layer), the capping layer (Capping Layer, light efficiency improvement) layer), it can be seen that the efficiency can be increased.

From the results of Table 2 above, a specific benzazole derivative compound according to the present invention can be used as a material for a low refractive index capping layer of an organic electronic device including an organic light emitting device, and an organic electronic device including an organic light emitting device using the same is effective , it can be seen that it exhibits excellent characteristics in driving voltage, stability, etc.

A device that uses only a single layer as a high refractive index (n> 1.69 @620 nm) compound as a capping layer, a high refractive index (n> 1.69 @ 620 nm) compound, and a low refractive index (n < 1.69 @ 620 nm) compound If you look at the results of the device using multiple layers, it can be confirmed that the capping layer (light efficiency improvement layer) used as a multilayer can increase the efficiency, and Alq ₃ is used as the capping layer (light efficiency improvement layer). It can be seen that the efficiency is improved when the material of the present invention is used in multiple layers than the device used (Comparative Example 2).

This can be explained by the refractive index, and it is obvious that the organic electroluminescent device using the compound of the present invention having a higher refractive index (high refractive index) and a lower refractive index (low refractive index) than a REF01 single layer having a high refractive index has high efficiency. it's a thing

Therefore, the compound of Formula 1 has unexpectedly desirable properties for use as a low refractive index capping layer in an OLED.

The compound of the present invention can be applied to industrial organic electronic device products due to these properties.

However, the above-described synthesis example is an example, and the reaction conditions may be changed as necessary. In addition, the compound according to an embodiment of the present invention may be synthesized to have various substituents using methods and materials known in the art. By introducing various substituents into the core structure represented by Formula 1, it may have properties suitable for use in an organic electroluminescent device.

100: substrate, 110: first electrode, 120: second electrode, 200: organic material layer, 210: hole injection layer, 215: hole transport layer, 220: light emitting layer, 230: electron transport layer, 235: electron injection layer, 300: capping layer

Claims (7)

A benzazole derivative for an organic light emitting device, represented by the following formula (1).
[Formula 1]

In Formula 1,
Z ₁ is O, S or NR with the proviso that R is phenyl;
X ₁ , X ₂ , X _{3 ,} X ₄ and X ₅ are each independently CH or N,
Ar ₁ is selected from H, a methyl group, a tert-butyl group, F, CF ₃ , CN and Si(CH ₃ ) ₃ ,
L ₁ is a direct bond; or a substituted or unsubstituted arylene group; Or a substituted or unsubstituted heteroarylene group;
n is an integer from 0 to 5,
R ₁ to R ₅ are each independently any one selected from an alkyl group, H, F, CF ₃ , CN, and Si(CH ₃ ) _{3 ,}
m is an integer of 1 to 2. The method of claim 1,
L ₁ is a substituted or unsubstituted phenyl group; a substituted or unsubstituted pyridyl group; a substituted or unsubstituted naphthyl group; a substituted or unsubstituted anthracene group; a substituted or unsubstituted phenanthrine group; and a substituted or unsubstituted phenanthridine group. A benzazole derivative for an organic electroluminescent device. The method of claim 1,
Formula 1 is a benzazole derivative for an organic light emitting device selected from compounds of Formula 2 or Formula 3 below.
[Formula 2]

[Formula 3]

The method of claim 1,
The benzazole derivative is a benzazole derivative for an organic light emitting device, characterized in that the refractive index constant is less than 1.69 (@620nm). a first electrode;
an organic material layer formed of a plurality of organic material layers disposed on the first electrode;
a second electrode disposed on the organic material layer; and
a capping layer disposed on the second electrode; and
The organic material layer or the capping layer is an organic electroluminescent device comprising the benzazole derivative according to any one of claims 1 to 4. 6. The method of claim 5,
The capping layer is an organic electroluminescent device comprising a plurality of layers having different refractive indices. 6. The method of claim 5,
The organic material layer includes an emission layer and an electron transport layer, and the electron transport layer includes the benzazole derivative.

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