KR20220015894A - New compound for capping layer and Organic light emitting diode comprising to the same - Google Patents

Abstract

The present invention provides a compound for a capping layer represented by chemical formula 1, and an organic light emitting device including the same. The compound for forming the capping layer according to the present invention can maintain a wide band gap in which it is difficult to absorb a visible light region, thereby realizing high color purity.

Description

New compound for capping layer and organic light emitting diode comprising the same

The present invention relates to a novel capping layer compound and an organic light emitting device comprising the same.

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

In addition, the light emitting material can be classified into a fluorescent material derived from a singlet excited state of electrons and a phosphorescent material derived from a triplet excited state of electrons according to the light emission mechanism, and can be classified into blue, green, and red light emitting materials according to the emission color. can be distinguished.

A typical organic light emitting device may have a structure in which an anode is formed on a substrate, and a hole transport layer, a light emitting layer, an electron transport layer, and a cathode are sequentially formed on the anode. Here, the hole transport layer, the light emitting layer, and the electron transport layer are organic thin films made of an organic compound.

The driving principle of the organic light emitting diode having the above-described structure is as follows.

When a voltage is applied between the anode and the cathode, holes injected from the anode move to the emission layer via the hole transport layer, and electrons injected from the cathode move to the emission layer via the electron transport layer. The holes and electrons recombine in the emission layer to generate excitons.

Light is generated as this exciton changes from an excited state to a ground state. The efficiency of organic light emitting diodes can be generally divided into internal luminous efficiency and external luminous efficiency. The internal luminous efficiency is related to how efficiently excitons are generated in the organic layer interposed between the first and second electrodes, such as a hole transport layer, a light emitting layer, and an electron transport layer, to achieve light conversion. Theoretically, in the case of fluorescence, 25%, phosphorescence is known to be 100%.

On the other hand, the external luminous efficiency refers to the efficiency at which light generated in the organic layer is extracted to the outside of the organic light emitting device, and it is known that it is usually extracted to the outside by about 20% of the internal luminous efficiency. As a method to increase this light extraction, various organic compounds having a refractive index of 1.7 or higher have been applied as a capping layer to prevent total reflection and loss of light going out to the outside Efforts have been made to develop organic compounds having high refractive index and thin film stability.

Korean Patent Publication 10-2004-0098238

Accordingly, an object of the present invention is to have a wide bandgap and high refractive index that cannot absorb visible light, and at the same time increase the absorption wavelength in the ultraviolet region to realize high color purity, high efficiency, and long lifespan organic light emitting device for a capping layer compound and An object of the present invention is to provide an organic light emitting device including the same.

In addition, an object of the present invention is to improve the refractive index due to excellent intermolecular thin film arrangement, prevent intermolecular recrystallization with high glass transition temperature (Tg) and decomposition temperature (Td), and maintain a stable thin film from heat generated during operation, An object of the present invention is to provide a compound for a capping layer and an organic light emitting device that can protect the device from external air and moisture to improve stability, increase external quantum efficiency, and significantly improve lifespan.

The above tasks and additional tasks will be described in detail below.

As a means for solving the above problems,

As an embodiment, the present invention provides a compound for a capping layer represented by the following Chemical Formula 1:

[Formula 1]

[Formula 1-1]

In Formula 1 and Formula 1-1,

Ar ₁ and Ar ₂ are each independently a substituted or unsubstituted C6~ C50 aryl group, or a substituted or unsubstituted C2~ C50 heteroaryl group, wherein at least one of Ar ₁ and Ar ₂ is a condensed aryl group or hetero an aryl group,

Ar ₃ is Formula 1-1,

X ₁ to X ₁₀ are each independently C, CR, or N, but only one of X ₁ to X ₁₀ is N,

R is hydrogen, deuterium, halogen, nitro group, nitrile group, substituted or unsubstituted C1-C30 alkyl group, substituted or unsubstituted C2-C30 alkenyl group, substituted or unsubstituted C1-C30 alkoxy group, substituted Or an unsubstituted C1~ C30 sulfide group, a substituted or unsubstituted C6~ C50 aryl group, or a substituted or unsubstituted C2~ C50 heteroaryl group, and when R is two or more, they may be the same as or different from each other, ,

L ₁ and L ₂ are each independently a direct bond, a substituted or unsubstituted C6~ C50 arylene group, or a substituted or unsubstituted C2~ C50 heteroarylene group,

L ₃ is a substituted or unsubstituted C6~ C50 arylene group, or a substituted or unsubstituted C2~ C50 heteroarylene group,

* is a position bonded to L ₃ .

In addition, the present invention is an embodiment,

An organic light emitting device containing the above-described compound for a capping layer is provided.

The compound for forming a capping layer according to the present invention has an arylamine structure to which a quinoline group is bonded, and when applied as a capping layer of an organic light emitting device, it is easy to maintain a high refractive index and at the same time it is possible to maintain a wide band gap that is difficult to absorb the visible light region. High color purity can be realized.

In addition, since the compound for forming a capping layer according to the present invention is extended with a linking group between the quinoline group and the amine, the intermolecular thin film arrangement is excellent and at the same time it can be effective in increasing the absorption wavelength in the ultraviolet region, thus improving the refractive index and exposure to ultraviolet rays It is easy to improve stability from outside air and moisture.

Furthermore, the compound for forming a capping layer according to the present invention can form a high glass transition temperature (Tg) and a decomposition temperature (Td) by applying a heterobicyclic condensing group such as a quinoline group, and thereby the capping layer of the organic light emitting device When applied, it is possible to prevent intermolecular recrystallization and maintain a stable thin film from heat generated during operation.

The above effects and additional effects will be described in detail below.

1 is a schematic cross-sectional view showing the configuration of an organic light emitting device according to an embodiment of the present invention.
2 is a capping layer according to an embodiment of the present invention compounds 47 and 188 and Ref. 1 and Ref. It is a graph measuring the absorption intensity within the range of 340 nm to 460 nm for the 2 compounds.

Prior to describing the present invention in detail below, it is to be understood that the terminology used herein is for the purpose of describing specific embodiments and is not intended to limit the scope of the present invention, which is limited only by the appended claims. shall. All technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art, unless otherwise stated.

Throughout this specification and claims, unless stated otherwise, the term comprise, comprises, comprising is meant to include the stated object, step or group of objects, and steps, and any other object. It is not used in the sense of excluding a step or a group of objects or groups of steps.

Throughout this specification and claims, the term "aryl" refers to a C6-C50 aromatic hydrocarbon ring group, such as phenyl, benzyl, naphthyl, biphenyl, terphenyl, fluorene, phenanthrenyl, triphenyl It is meant to include an aromatic ring such as renyl, perylenyl, chrysenyl, fluoranthenyl, benzofluorenyl, benzotriphenylenyl, benzochrysenyl, anthracenyl, stilbenyl, pyrenyl, and the like.

In addition, the term "heteroaryl" is a C2-C50 aromatic ring containing one or more heteroatoms, for example, pyrrolyl, pyrazinyl, pyridinyl, indolyl, isoindolyl, furyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, benzothiophenyl, dibenzothiophenyl, quinolyl group, isoquinolyl, quinoxalinyl, carbazolyl, phenanthridinyl, acridinyl, phenanthrolinyl, thienyl, and Pyridine, pyrazine, pyrimidine, pyridazine, triazine, indole, quinoline, acridine, pyrrolidine, dioxane, piperidine, morpholine, piperazine, carbazole, furan, thiophene, oxazole, oxa It may mean containing a heterocyclic group such as diazole, benzoxazole, thiazole, thiadiazole, benzothiazole, triazole, imidazole, benzoimidazole, pyran, dibenzofuran.

In addition, in the formula, Ar _x (where x is an integer) means, unless specifically defined, a substituted or unsubstituted C6~C50 aryl group, or a substituted or unsubstituted C2~C50 heteroaryl group, L _x (here x is an integer) refers to a direct bond, a substituted or unsubstituted C6~ C50 arylene group, or a substituted or unsubstituted C2~C50 heteroarylene group, unless otherwise defined, and R _x (where x is an integer) ) is hydrogen, deuterium, halogen, nitro group, nitrile group, substituted or unsubstituted C1~ C30 alkyl group, substituted or unsubstituted C2~ C30 alkenyl group, substituted or unsubstituted C1~ It refers to a C30 alkoxy group, a substituted or unsubstituted C1~C30 sulfide group, a substituted or unsubstituted C6~C50 aryl group, or a substituted or unsubstituted C2~C50 heteroaryl group.

Throughout this specification and claims, the term "substituted or unsubstituted" refers to deuterium, halogen, amino group, cyano group, nitrile group, nitro group, nitroso group, sulfamoyl group, isothiocyanate group, thiocyanate group , carboxyl group, or C1 to C30 alkyl group, C1 to C30 alkylsulfinyl group, C1 to C30 alkylsulfonyl group, C1 to C30 alkylsulfanyl group, C1 to C12 fluoroalkyl group, C2 to C30 alkenyl group, C1 -C30 alkoxy group, C1-C12 N-alkylamino group, C2-C20 N,N-dialkylamino group, C1-C6 N-alkylsulfamoyl group, C2-C12 N,N-dialkylsulfamo Diyl, C3~ C30 silyl group, C3~ C20 cycloalkyl group, C3~ C20 heterocycloalkyl group, C6~ C50 aryl group, C3~ C50 heteroaryl group, etc. substituted or substituted with one or more groups selected from the group consisting of It could mean that it doesn't. In addition, the same symbols throughout the present specification may have the same meaning unless otherwise specified.

On the other hand, various embodiments of the present invention may be combined with any other embodiments unless clearly indicated to the contrary. Hereinafter, embodiments of the present invention and effects thereof will be described.

Hereinafter, the present invention will be described in detail.

The compound for a capping layer according to the present invention may be represented by the following Chemical Formula 1:

[Formula 1]

[Formula 1-1]

In Formula 1 and Formula 1-1,

Ar ₁ and Ar ₂ are each independently a substituted or unsubstituted C6~ C50 aryl group, or a substituted or unsubstituted C2~ C50 heteroaryl group, wherein at least one of Ar ₁ and Ar ₂ is a condensed aryl group or hetero an aryl group,

Ar ₃ is Formula 1-1,

X ₁ to X ₁₀ are each independently C, CR, or N, but only one of X ₁ to X ₁₀ is N,

R is hydrogen, deuterium, halogen, nitro group, nitrile group, substituted or unsubstituted C1-C30 alkyl group, substituted or unsubstituted C2-C30 alkenyl group, substituted or unsubstituted C1-C30 alkoxy group, substituted Or an unsubstituted C1~ C30 sulfide group, a substituted or unsubstituted C6~ C50 aryl group, or a substituted or unsubstituted C2~ C50 heteroaryl group, and when R is two or more, they may be the same as or different from each other, ,

L ₁ and L ₂ are each independently a direct bond, a substituted or unsubstituted C6~ C50 arylene group, or a substituted or unsubstituted C2~ C50 heteroarylene group,

L ₃ is a substituted or unsubstituted C6~ C50 arylene group, or a substituted or unsubstituted C2~ C50 heteroarylene group,

* is a position bonded to L ₃ .

The compound for forming a capping layer represented by Formula 1 according to the present invention has an arylamine structure to which a quinoline group is bonded, and when applied as a capping layer of an organic light emitting device, it is easy to maintain a high refractive index and at the same time a broad band that is difficult to absorb the visible light region It is possible to maintain the gap, so that high color purity can be realized.

In addition, since the compound for forming a capping layer represented by Formula 1 according to the present invention is extended with a linking group between the quinoline group and the amine, the intermolecular thin film arrangement is excellent and at the same time it can be effective in increasing the absorption wavelength in the ultraviolet region, and thus the refractive index It is easy to improve as well as improve stability from UV exposure and stability from outside air and moisture.

Furthermore, the compound for forming a capping layer represented by Formula 1 according to the present invention can form a high glass transition temperature (Tg) and a decomposition temperature (Td) by applying a heterobicyclic condensed group such as a quinoline group, thereby When applied as a capping layer of a light emitting device, it is possible to prevent intermolecular recrystallization and maintain a stable thin film from heat generated during operation.

Specifically, in Formula 1-1, X1 may be N, and X3 may be bonded to L3. Since the compound represented by Formula 1 has such a structure, it is possible to maintain a high refractive index and minimize absorption in the visible light region.

Specifically, in Formula 1, at least one of Ar ₁ and Ar ₂ may be represented by Formula 1-1, wherein Ar ₁ and Ar ₂ may be the same as or different from each other. The compound represented by Formula 1 may have a higher refractive index by including two or more cores by having such a structure.

In addition, in Formula 1, at least one of Ar ₁ and Ar ₂ may be a condensed heteroaryl group, and specifically may be represented by Formula 1-2 below. In this case, Ar ₁ and Ar ₂ may be the same as or different from each other. The compound represented by the formula (1) may have a higher refractive index by increasing the polarization by having such a structure, and with it, the absorption intensity in the ultraviolet region may be improved:

[Formula 1-2]

.

.

In Formula 1-2,

X ₁₁ to X ₁₉ are each independently C, CR, O, S, N, Se, Te, NR, CRR', SiRR', or GeRR'.

Specifically, X ₁₅ to X ₁₈ are CR, X ₁₂ is C, and may be a connecting portion with L ₁ or L ₂ .

In addition, X ₁₁ may be CR or N, X ₁₃ may be O, S or NR, X ₁₄ may be C, or X ₁₁ may be CR or N, X ₁₃ may be CR, and X ₁₄ may be N.

The compound represented by Formula 1 according to the present invention includes a fused heteroaryl group represented by Formula 1-1 in Ar ₃ , and at the same time a fused aryl group or a fused heteroaryl group represented by Formula 1-2 different from Formula 1-1 A higher refractive index may be realized by including the group in at least one of Ar ₁ and Ar ₂ . Specifically, Ar ₁ may be in Formula 1-1, and Ar ₂ may be in Formula 1-2.

In addition, Chemical Formula 1 according to the present invention may be represented by Chemical Formula 2 below. In this case, the capping layer compound represented by Chemical Formula 1 is connected to an amine group through a phenylene group adjacent to Chemical Formula 1-1 to minimize the absorption wavelength in the blue region, and together with it, it is possible to effectively improve the refractive index:

[Formula 2]

In Formula 2,

Ar ₁ , Ar ₂ , L ₁ , L ₂ , X ₁ to X ₁₀ are the same as in Formula 1,

R ₁ is the same as R in Formula 1,

l is an integer from 1 to 5;

Specifically, Formula 1 may be represented by any one of Formulas 3 to 5:

[Formula 3]

[Formula 4]

[Formula 5]

In Formulas 3 to 5,

Ar ₁ , Ar ₂ , X ₁ to X ₁₀ are the same as in Formula 1 (provided that the number of carbon atoms of X ₁ to X ₁₀ satisfies the range of carbon numbers defined in Ar ₁ or Ar ₂ ),

L ₁ and L ₂ are each independently a direct bond, a substituted or unsubstituted C6~ C50 arylene group, or a substituted or unsubstituted C2~ C50 heteroarylene group, specifically a substituted or unsubstituted C6~ C50 arylene group An arylene group, or a substituted or unsubstituted C2~ C50 heteroarylene group,

m is an integer from 1 to 3.

In the compound represented by Chemical Formulas 3 to 5, at least one of Ar ₁ to Ar ₃ is Chemical Formula 1-1, and L ₃ is a para-phenylene group (1,4 in case of m=2 to 3) capable of linking group extension. -phenylene group). In this case, the compounds have an advantage in that the absorption wavelength in the ultraviolet region is increased while implementing a high refractive index, so that stability from external ultraviolet exposure is improved.

In particular, when two or more condensed heteroaryl groups are included as in the compound represented by Formula 4 and/or Formula 5, the refractive index may be further increased.

In addition, L ₁ and L ₂ are each independently an arylene group or a heteroarylene group, thereby increasing the refractive index and at the same time improving the absorption intensity in the ultraviolet region.

In addition, Formula 1 may be represented by any one of Formulas 6 to 9 below:

[Formula 6]

[Formula 7]

[Formula 8]

[Formula 9]

In Formulas 6 to 9,

Ar ₁ , L ₁ , L ₂ , X ₁ to X ₁₀ are the same as in Formula 1,

X ₁₁ , X ₁₃ and X ₁₄ are each independently C, O, S, N, CR or NR,

m is an integer from 1 to 3.

The compounds represented by Chemical Formulas 6 to 9 include a para-phenylene group (1,4-phenylene group) in which L ₃ is capable of linking group expansion (when m=2 to 3), and any one of Ar ₁ and Ar ₂ It is a compound comprising at least one of Formula 1-2. In this case, absorption intensity in the ultraviolet region may be improved, and a higher refractive index may be realized.

Furthermore, any one of X ₁ to X ₄ may be N. Formula 1-1, wherein any one of X ₁ to X ₄ is N, is a quinoline group, and when it is included in the compound represented by Formula 1, intramolecular polarization is increased to have a higher refractive index, and light in the ultraviolet region It can be effective in increasing absorption strength.

As an example, Chemical Formula 1 may be represented by any one of Chemical Formulas 10 to 12 below:

[Formula 10]

[Formula 11]

[Formula 12]

In Formulas 10 to 12,

Ar ₁ , Ar ₂ , L ₁ and L ₂ are the same as in Formula 1,

m is an integer from 1 to 3.

In the compounds represented by Chemical Formulas 10 to 12, L ₃ is a para-phenylene group (1,4-phenylene group) capable of linking group expansion (when m=2 to 3), and Ar ₁ to Ar ₃ Any one or more This compound is a quinoline group. The compounds represented by Chemical Formulas 10 to 12 may have a higher refractive index while minimizing light absorption in a visible light region by having the structure as described above.

Meanwhile, in Formula 1, L ₁ to L ₃ may each independently be a phenylene group, a biphenylene group, or a combination thereof. As an example, the L ₁ to L ₃ may each independently be a 1,4-phenylene group, and in this case, it is possible to reduce the deposition temperature while maintaining a high refractive index by minimizing the bulky characteristic of the linking group adjacent to the amine. There are advantages.

In addition, Ar ₁ and Ar ₂ may each independently be a condensed aryl group consisting of two rings or a condensed heteroaryl group consisting of two rings.

When Ar ₁ and Ar ₂ are a condensed aryl group consisting of two rings, absorption in the visible region can be minimized and high refractive index can be exhibited at the same time, and when Ar ₁ and Ar ₂ are a condensed heteroaryl group consisting of two rings, a high refractive index is exhibited as well. However, it is possible to increase absorption in the ultraviolet region.

As an example, each of Ar ₁ and Ar ₂ may be independently selected from the group consisting of a benzofuran group, a benzothiophene group, an indolizine group, an imidazopyridine group, and a benzoxazole group, and thus, represented by Formula 1 The displayed compound for the capping layer can maintain a high refractive index by minimizing the bulky characteristic of the terminal group, and at the same time can effectively improve the deposition temperature.

The following compounds are specific examples of the compounds according to the present invention. The following examples are only examples for explaining the present invention, and thus the present invention is not limited thereto:

An embodiment of the compound for the capping layer of the present invention may be synthesized by an amination reaction, and a schematic synthesis reaction scheme is as follows.

In another embodiment, the present invention provides an organic light emitting device including the above-described compound for a capping layer according to the present invention in a capping layer.

Hereinafter, an organic light emitting device according to the present invention will be described in more detail.

According to one embodiment of the present invention, the organic light emitting device may include a first electrode, a second electrode, one or more organic material layers and a capping layer interposed inside the first electrode and the second electrode, and the cap The ping layer may be disposed outside any one or more of the first electrode and the second electrode.

Specifically, a side adjacent to the organic material layer interposed between the first electrode and the second electrode among both surfaces of the first electrode or the second electrode is referred to as an inner side, and a side not adjacent to the organic material layer is referred to as an outer side. That is, when the capping layer is disposed outside the first electrode, the first electrode is interposed between the capping layer and the organic material layer, and when the capping layer is disposed outside the second electrode, the second electrode is interposed between the capping layer and the organic material layer do.

In addition, according to one embodiment of the present invention, in the organic light emitting device, one or more various organic material layers may be interposed inside the first electrode and the second electrode, and at least one of the first electrode and the second electrode may be disposed outside the first electrode and the second electrode. A capping layer may be formed thereon. That is, the capping layer may be formed on both the outer side of the first electrode and the outer side of the second electrode, or may be formed only on the outer side of the first electrode or the outer side of the second electrode.

In this case, the capping layer may include the compound for the capping layer according to the present invention, and may include the compound for the capping layer according to the present invention alone, include two or more kinds, or include a known compound together.

Furthermore, the capping layer may have a refractive index of 2.25 or more, specifically 2.30 or more, and more specifically 2.32 or more, at a wavelength of 450 nm, and an ultraviolet absorption intensity of 0.7 or more, specifically 0.8 or more, or 0.9 or more at a wavelength of 380 nm.

Meanwhile, the organic material layer may generally include a hole transport layer, a light emitting layer, and an electron transport layer constituting the light emitting part, but may not be limited thereto.

More specifically, the organic light emitting device according to an embodiment of the present invention includes a hole injection layer (HIL), a hole transport layer (HTL), a light emitting layer (HTL) between a first electrode (anode) and a second electrode (cathode) ( EML), an electron transport layer (ETL), an electron injection layer (EIL) may include one or more organic material layers constituting the light emitting portion.

1 is a cross-sectional view schematically showing the configuration of an organic light emitting device according to an embodiment of the present invention. The organic light emitting device according to an embodiment of the present invention may be manufactured as shown in FIG. 1 .

As shown in FIG. 1 , the organic light emitting device includes a substrate 100 , a first electrode 1000 , a hole injection layer 200 , a hole transport layer 300 , a light emitting layer 400 , an electron transport layer 500 , and an electron injection layer from the bottom. 600 , the second electrode 2000 , and the capping layer 3000 may be sequentially stacked.

Here, as the substrate 100, a substrate generally used in organic light emitting devices may be used, and in particular, a transparent glass substrate or a flexible plastic substrate excellent in mechanical strength, thermal stability, transparency, surface smoothness, handling, and waterproofness. can be

In addition, the first electrode 1000 is used as a hole injection electrode for hole injection of the organic light emitting device. The first electrode 1000 is manufactured using a material having a low work function to enable hole injection, and is formed of a transparent material such as indium tin oxide (ITO), indium zinc oxide (IZO), or graphene. can be

In addition, the hole injection layer 200 is formed by depositing a hole injection layer material on the first electrode 1000 by a method such as a vacuum deposition method, a spin coating method, a casting method, or a Langmuir-Blodgett (LB) method. can be In the case of forming the hole injection layer 200 by the vacuum deposition method, the deposition conditions vary depending on the compound used as the material of the hole injection layer 200, the structure and thermal characteristics of the hole injection layer 200, etc. In general, a deposition temperature of 50-500° C., a vacuum degree of 10 ^-8 to 10 ^-3 torr, a deposition rate of 0.01 to 100 Å/sec, and a layer thickness of 10 Å to 5 μm may be appropriately selected. Meanwhile, a charge generating layer may be additionally deposited on the surface of the hole injection layer 200 if necessary. A conventional material may be used as the material for the charge generation layer, for example, HATCN.

In addition, the hole transport layer 300 may be formed by depositing a hole transport layer material on the hole injection layer 200 by a method such as a vacuum deposition method, a spin coating method, a casting method, a LB method, or the like. In the case of forming the hole transport layer 300 by the vacuum deposition method, the deposition conditions vary depending on the compound used, but in general, it is preferable to select within the same range of conditions as those of the hole injection layer 200 . The hole transport layer 300 may be formed using a known compound. The hole transport layer 300 may have one or more layers, and although not shown in FIG. 1 , a light emitting auxiliary layer may be additionally formed on the hole transport layer 300 .

In addition, the light emitting layer 400 may be formed by depositing a light emitting layer material on the hole transport layer 300 or the light emitting auxiliary layer by a method such as vacuum deposition, spin coating, casting, LB method, or the like. In the case of forming the light emitting layer 400 by the vacuum deposition method, the deposition conditions vary depending on the compound used, but in general, it is preferable to select within the same range of conditions as those for the formation of the hole injection layer 200 . As the light emitting layer material, a known compound may be used as a host or a dopant.

Here, when a phosphorescent dopant is used together in the light emitting layer material, a hole blocking material (HBL) is added on the light emitting layer 400 to prevent the triplet excitons or holes from diffusing into the electron transport layer 500 by vacuum deposition or It can be laminated through a spin coating method. The hole-blocking material that can be used is not particularly limited, and a known material can be arbitrarily selected and used. For example, an oxadiazole derivative, a triazole derivative, a phenanthroline derivative, or a hole-inhibiting material described in Japanese Patent Application Laid-Open No. Hei 11-329734 (A1), etc. are mentioned. Representatively, Balq (bis(8-hydra) Roxy-2-methylquinolinol nato)-aluminum biphenoxide), phenanthrolines-based compounds (eg, UDC's BCP (vasocuproin)), etc. may be used. The light emitting layer 400 of the present invention may include one or more or two or more blue light emitting layers.

In addition, the electron transport layer 500 is formed on the light emitting layer 400, and may be formed by a method such as a vacuum deposition method, a spin coating method, a casting method. The deposition conditions of the electron transport layer 500 vary depending on the compound used, but in general, it is preferable to select the electron transport layer 500 in the same condition range as the formation of the hole injection layer 200 .

Furthermore, the electron injection layer 600 may be formed by depositing an electron injection layer material on the electron transport layer 500 , and may be formed by a vacuum deposition method, a spin coating method, a casting method, or the like.

In addition, the second electrode 2000 is used as an electron injection electrode, and may be formed on the electron injection layer 600 by a method such as a vacuum deposition method or a sputtering method. Various metals may be used as a material of the second electrode 2000 . Specific examples include, but are not limited to, materials such as aluminum, gold, silver, and magnesium.

The organic light emitting device of the present invention has the above-described capping layer 3000, the first electrode 1000, the hole injection layer 200, the hole transport layer 300, the light emitting layer 400, the electron transport layer 500, the electron injection layer ( 600), an organic light emitting device having a structure including the second electrode 2000 and the capping layer 3000, as well as an organic light emitting device having a variety of structures are possible. It is also possible to include

On the other hand, the thickness of each organic material layer formed according to the present invention can be adjusted according to the required degree, specifically 10 to 1,000 nm, more specifically, may be 20 to 150 nm.

As shown in FIG. 1 , the capping layer 3000 may be formed on an outer surface on which the hole injection layer 200 is not formed among both sides of the first electrode 1000 . In addition, the second electrode 2000 may be formed on the outer side on which the electron injection layer 600 is not formed among both side surfaces, but is not limited thereto. The capping layer 3000 may be formed by a deposition process, and the capping layer 3000 may have a thickness of 100 to 2,000 Å, more specifically, 300 to 1,000 Å. Through such thickness control, it is possible to prevent a decrease in transmittance of the capping layer 3000 .

In addition, although not shown in FIG. 1 , according to an exemplary embodiment of the present invention, various functions are provided between the capping layer 3000 and the first electrode 1000 or between the capping layer 3000 and the second electrode 2000 . An organic layer may be additionally formed. Alternatively, an organic material layer having various functions may be additionally formed on the upper portion (outer surface) of the capping layer 3000 , but is not limited thereto.

Hereinafter, the present invention will be described in more detail through a synthesis example of a compound according to an embodiment of the present invention and an example of an organic light emitting device. The following synthesis examples and examples only illustrate the present invention, but the scope of the present invention is not limited to the following examples.

< Synthesis example 1> Synthesis of compound 37

100ml of toluene was injected into a round bottom flask, 2-(4-bromophenyl)naphthalene 2.0g, bis(4-(quinolin-3-yl)phenyl)amine 3.29g, t-BuONa 1.1g, Pd ₂ (dba) ₃ 0.3 g, (t-Bu) ₃ P 0.3ml was dissolved and stirred under reflux. The reaction progress was confirmed by TLC (Thin Layer Chromatography), and the reaction was terminated after addition of water. The organic layer was extracted with methylene chloride (MC), filtered under reduced pressure, and recrystallized to obtain compound 37, 2.9 g (yield 66%).

m/z: 625.25 (100.0%), 626.26 (50.1%), 627.26 (12.3%), 628.26 (2.1%), 626.25 (1.1%)

< Synthesis example 2> Synthesis of compound 47

Compound 47 (yield 67%) was synthesized in the same manner as in Synthesis Example 1, except that 3-(4-bromophenyl)quinoline was used in the same amount instead of 2-(4-bromophenyl)naphthalene.

m/z: 626.25 (100.0%), 627.25 (49.0%), 628.25 (12.3%), 629.26 (1.8%), 627.24 (1.5%)

< Synthesis example 3> Synthesis of compound 181

It was carried out in the same manner as in Synthesis Example 1, but instead of 2-(4-bromophenyl)naphthalene and bis(4-(quinolin-3-yl)phenyl)amine, 3-(4-bromophenyl)quinoline and bis(4-(benzofuran- Compound 181 (yield 65%) was synthesized using the same equivalent of 2-yl)phenyl)amine.

m/z: 604.22 (100.0%), 605.22 (46.9%), 606.22 (11.5%), 607.23 (1.6%)

< Synthesis example 4> Synthesis of compound 182

Compound 182 (yield 64%) was synthesized in the same manner as in Synthesis Example 1, except that 2-(4-bromophenyl)benzofuran was used in the same amount instead of 2-(4-bromophenyl)naphthalene.

m/z: 615.23 (100.0%), 616.23 (48.7%), 617.24 (11.4%), 618.24 (1.8%)

< Synthesis example 5> Synthesis of compound 183

It was carried out in the same manner as in Synthesis Example 1, but instead of 2-(4-bromophenyl)naphthalene and bis(4-(quinolin-3-yl)phenyl)amine, 3-(4-bromophenyl)quinoline and bis(4-(benzo[ Compound 183 (yield 65%) was synthesized using the same equivalent of b]thiophen-2-yl)phenyl)amine.

m/z: 636.17 (100.0%), 637.17 (48.8%), 638.18 (10.7%), 638.17 (10.1%), 639.17 (4.3%), 639.18 (1.8%), 640.17 (1.0%)

< Synthesis example 6> Synthesis of compound 184

Compound 184 (yield 66%) was synthesized in the same manner as in Synthesis Example 1, but using the same equivalent of 2-(4-bromophenyl)benzo[b]thiophene instead of 2-(4-bromophenyl)naphthalene.

m/z: 631.21 (100.0%), 632.21 (49.8%), 633.21 (12.0%), 633.20 (4.5%), 634.21 (2.4%), 634.22 (1.7%)

< Synthesis example 7> Synthesis of compound 187

It was carried out in the same manner as in Synthesis Example 1, but instead of 2-(4-bromophenyl)naphthalene and bis(4-(quinolin-3-yl)phenyl)amine, 3-(4-bromophenyl)quinoline and bis(4-(benzo[ Compound 187 (yield 68%) was synthesized using the same equivalent of d]oxazol-2-yl)phenyl)amine.

m/z: 606.21 (100.0%), 607.21 (44.7%), 608.21 (10.7%), 607.20 (1.5%), 609.22 (1.4%)

< Synthesis example 8> Synthesis of compound 188

Compound 188 (yield 67%) was synthesized in the same manner as in Synthesis Example 1, but using the same equivalent of 2-(4-bromophenyl)benzo[d]oxazole instead of 2-(4-bromophenyl)naphthalene.

m/z: 616.23 (100.0%), 617.23 (46.9%), 618.23 (11.5%), 619.24 (1.6%), 617.22 (1.5%)

< Synthesis example 9> Synthesis of compound 195

It was carried out in the same manner as in Synthesis Example 1, but instead of 2-(4-bromophenyl)naphthalene and bis(4-(quinolin-3-yl)phenyl)amine, 3-(4-bromophenyl)quinoline and bis(4-(imidazo[ Compound 195 (yield 58%) was synthesized using the same equivalent of 1,2-a]pyridin-2-yl)phenyl)amine.

m/z: 604.24 (100.0%), 605.24 (44.7%), 606.24 (10.6%), 605.23 (2.2%), 607.25 (1.4%)

< Synthesis example 10> Synthesis of compound 196

Compound 196 (yield: 60%) was synthesized in the same manner as in Synthesis Example 1, but using the same equivalent of 2-(4-bromophenyl)imidazo[1,2-a]pyridine instead of 2-(4-bromophenyl)naphthalene did

m/z: 615.24 (100.0%), 616.25 (46.8%), 617.25 (10.7%), 616.24 (1.8%), 618.25 (1.8%)

Manufacturing of organic light emitting devices

1 shows the structure of a general organic light emitting device, the present invention is an example, and has the structure of the organic light emitting device shown in FIG. 1 , but a charge generating layer (not shown) between the hole injection layer 200 and the hole transport layer 300 ) and an electron injection layer (not shown) between the electron transport layer 500 and the cathode 2000 was additionally introduced. Specifically, the manufactured organic light emitting device is an anode (hole injection electrode 1000) / hole injection layer 200 / charge generation layer (not shown) / hole transport layer 300 / light emitting layer 400 / electron transport layer ( 500) / electron injection layer 600 / electron injection cathode (electron injection electrode 2000) / capping layer 3000 are stacked in this order.

When manufacturing an organic light emitting device, the substrate 10 may be a transparent glass substrate or a flexible plastic substrate.

The hole injection electrode 1000 is used as an anode for hole injection of the organic light emitting diode. A material having a low work function is used to enable hole injection, and may be formed of a transparent material such as indium tin oxide (ITO), indium zinc oxide (IZO), or graphene.

Materials listed in Table 1 below were used for the hole injection layer 200 , the charge generation layer, the hole transport layer 300 , the light emitting layer 400 , the electron transport layer 500 , and the electron injection layer 600 .

In addition, a cathode 2000 for electron injection was formed on the electron injection layer 600 . Various metals may be used as the cathode. Specific examples include materials such as aluminum, gold, and silver.

HI01 HATCN HT01

BH01 BD01 ET01

Liq

< Example 1>

The indium tin oxide (ITO) substrate on which the reflective layer containing silver (Ag) was formed was washed with distilled water and ultrasonic waves. After washing with distilled water, ultrasonic washing was performed with a solvent such as isopropyl alcohol, acetone, and methanol and dried. Thereafter, HI01 600 Å as a hole injection layer and HATCN 50 Å as a charge generating layer were respectively formed on the ITO substrate, and HT01 500 Å was formed as a hole transport layer. A film was formed to a thickness of 250 Å. Then, an electron transport layer was formed to a thickness of 300 Å with a mixture of ET01 and Liq (1:1, wt./wt.), and LiF was deposited at 10 Å to form an electron injection layer, followed by MgAg to 15 nm. A cathode was formed by vapor deposition. The compound prepared in Synthesis Example 1 was deposited to a thickness of 500 Å on the cathode as a capping layer. An organic light emitting device was manufactured by encapsulating the device in a glove box.

< Example 2> to < Example 10>

An organic light emitting diode was prepared in the same manner as in Example 1, but formed as a capping layer using the compounds prepared in Synthesis Examples 2 to 10, respectively.

< comparative example 1> to < comparative example 5>

Prepared in the same manner as in Example 1, Ref. 1 to Ref. An organic light emitting device in which a capping layer was formed by using each of 5 was manufactured.

Ref. One

Ref. 2

Ref. 3

Ref. 4

Ref. 5

< Experimental example 1> Performance evaluation of organic light emitting devices

Electrons and holes are injected by applying voltage with a Kiethley 2400 source measurement unit, and the luminance when light is emitted is measured using a Konica Minolta spectroradiometer (CS-2000). By doing so, the performances of the organic light emitting devices of Examples 1 to 10 and Comparative Examples 1 to 5 were evaluated by measuring the current density and luminance with respect to the applied voltage under atmospheric pressure conditions, and the results are shown in Table 3.

Op. V mA/cm ² Cd/A CIEx CIEy LT97 Example 1 3.45 10 7.78 0.140 0.044 158 Example 2 3.44 10 7.91 0.141 0.043 165 Example 3 3.44 10 8.05 0.139 0.045 171 Example 4 3.45 10 8.02 0.140 0.044 172 Example 5 3.44 10 8.10 0.141 0.043 172 Example 6 3.45 10 8.06 0.141 0.042 172 Example 7 3.44 10 8.07 0.140 0.044 178 Example 8 3.45 10 8.06 0.141 0.043 177 Example 9 3.44 10 8.05 0.140 0.045 182 Example 10 3.45 10 8.05 0.140 0.044 180 Comparative Example 1 3.46 10 6.93 0.136 0.052 105 Comparative Example 2 3.47 10 5.98 0.133 0.059 77 Comparative Example 3 3.46 10 7.00 0.136 0.051 116 Comparative Example 4 3.46 10 6.82 0.135 0.054 110 Comparative Example 5 3.51 10 4.25 0.130 0.072 44

Contrasting the embodiments of the present invention, it can be seen that the organic light emitting devices of the embodiment realize a low driving voltage, and the luminous efficiency and lifespan are remarkably improved.

Specifically, the organic light emitting device of the embodiment according to the present invention has an arylamine structure to which a compound constituting the capping layer is bonded to a quinoline group, compared to the organic light emitting device of Comparative Example 1, and can absorb the visible light region while maintaining a high refractive index. It can be seen that high color purity is realized because a wide band gap can be maintained.

In addition, compared with the organic light emitting device of Comparative Example 2, the organic light emitting device of the above example minimizes bulky characteristics by combining the quinoline group with N of the arylamine through a linking group in the compound constituting the capping layer, so that the thin film arrangement is excellent. Accordingly, the refractive index is greatly improved and the absorption wavelength in the ultraviolet region can be increased at the same time, and it is particularly effective in realizing a long-life organic light-emitting device.

In addition, in the organic light emitting devices of the above embodiments, compared to the organic light emitting devices of Comparative Examples 3 and 4, the compound constituting the capping layer includes a heterobicyclic structure of a structure different from each other together with a quinoline group, thereby further increasing the polarizability of the molecule. and can form a high Tg, thereby improving the refractive index and forming a stable thin film at the same time.

Furthermore, compared to the organic light emitting device of Comparative Example 5, the organic light emitting devices of the above embodiment constitute a capping layer with a compound having a structure in which a ring including N in a quinoline group is connected to the N side of arylamine to have a high refractive index and at the same time It is possible to increase the absorption intensity in the ultraviolet region and minimize the absorption wavelength in the visible region, so that it is possible to realize high efficiency, high color purity and long lifespan organic light emitting device.

< Experimental example 2> Refractive index evaluation

Compounds used in the formation of the capping layer in Examples and Comparative Examples, specifically, compounds 37, 47, 181, 182, 183, 184, 187, 188, 195 and 196 and Ref.1 to Ref.5 in Table 2, respectively A deposited film having a thickness of 30 nm on a silicon substrate was fabricated using vacuum deposition equipment, and the refractive index at a wavelength of 450 nm was measured using an ellipsometer device (JAWoollam Co. Inc, M-2000X). The results are summarized in Table 4 below.

@450nm refractive index, n compound 37 2.32 compound 47 2.35 compound 181 2.38 compound 182 2.36 compound 183 2.40 compound 184 2.38 compound 187 2.38 compound 188 2.38 compound 195 2.37 compound 196 2.37 Ref. One 2.15 Ref. 2 2.06 Ref. 3 2.16 Ref. 4 2.13 Ref. 5 2.05

As shown in Table 4, it can be confirmed that the compound according to the present invention exhibits a high refractive index of 2.25 or more, more specifically 2.30 or more, and a high refractive index of 2.32 or more. As described above, since the compound according to the present invention exhibits a high refractive index, when applied to a capping layer, an organic light emitting device having significantly improved external quantum efficiency and lifespan can be realized.

< Experimental example 3> Evaluation of UV absorption intensity

Compounds 47 and 188 used in forming the capping layer in Examples 2 and 8 and Ref. 1 and Ref. Using the compound of 2, a 30 nm-thick deposited film on a silicon substrate was fabricated using vacuum deposition equipment, and 340 nm to 460 nm using an ellipsometer (JAWoollam Co. Inc, M-2000X). The absorption wavelength within the range of was measured. The results are shown in FIG. 2 .

Referring to FIG. 2, compounds 47 and 188 according to the present invention have an absorption intensity of 0.7 or more, more specifically, 0.8 or more, in the UV absorption region of 380 nm wavelength, Ref. 1 and Ref. It can be confirmed that the absorption strength is increased by 40% or more, more specifically, by 60% or more compared to the compound of 2 . As described above, since the compound according to the present invention exhibits an effect of increasing the absorption wavelength in the ultraviolet region, when applied to the capping layer, an organic light emitting device having high color purity, high efficiency and long life can be realized.

100: substrate
200: hole injection layer
300: hole transport layer
400: light emitting layer
500: electron transport layer
600: electron injection layer
1000: first electrode (anode)
2000: second electrode (cathode)
3000: capping layer

Claims (17)

A compound for a capping layer represented by the following Chemical Formula 1:
[Formula 1]

[Formula 1-1]

(In Formula 1 and Formula 1-1,
Ar ₁ and Ar ₂ are each independently a substituted or unsubstituted C6~ C50 aryl group, or a substituted or unsubstituted C2~ C50 heteroaryl group, wherein at least one of Ar ₁ and Ar ₂ is a condensed aryl group or hetero an aryl group,
Ar ₃ is Formula 1-1,
X ₁ to X ₁₀ are each independently C, CR, or N, but only one of X ₁ to X ₁₀ is N,
R is hydrogen, deuterium, halogen, nitro group, nitrile group, substituted or unsubstituted C1-C30 alkyl group, substituted or unsubstituted C2-C30 alkenyl group, substituted or unsubstituted C1-C30 alkoxy group, substituted Or an unsubstituted C1~ C30 sulfide group, a substituted or unsubstituted C6~ C50 aryl group, or a substituted or unsubstituted C2~ C50 heteroaryl group, and when R is two or more, they may be the same as or different from each other, ,
L ₁ and L ₂ are each independently a direct bond, a substituted or unsubstituted C6~ C50 arylene group, or a substituted or unsubstituted C2~ C50 heteroarylene group,
L ₃ is a substituted or unsubstituted C6~ C50 arylene group, or a substituted or unsubstituted C2~ C50 heteroarylene group,
* is the position where it is bound to L ₃ ).
According to claim 1,
At least one of Ar ₁ and Ar ₂ is a compound for a capping layer of Formula 1-1.
According to claim 1,
At least one of Ar ₁ and Ar ₂ is a condensed heteroaryl group. A compound for a capping layer.
According to claim 1,
At least one of Ar ₁ and Ar ₂ is a compound for a capping layer represented by the following Chemical Formula 1-2:
[Formula 1-2]

(In Formula 1-2,
X ₁₁ to X ₁₉ are each independently C, CR, O, S, N, Se, Te, NR, CRR`, SiRR`, or GeRR`).
According to claim 1,
Formula 1 is a compound for a capping layer represented by Formula 2 below:
[Formula 2]

(In Formula 2,
Ar ₁ , Ar ₂ , L ₁ , L ₂ , X ₁ to X ₁₀ are the same as in Formula 1,
R ₁ is the same as R in Formula 1,
l is an integer from 1 to 5).
According to claim 1,
Formula 1 is a compound for a capping layer represented by any one of Formulas 3 to 5 below:
[Formula 3]

[Formula 4]

[Formula 5]

(In Formulas 3 to 5,
Ar ₁ , Ar ₂ , X ₁ to X ₁₀ are the same as in Formula 1 (provided that the number of carbon atoms of X ₁ to X ₁₀ satisfies the range of carbon numbers defined in Ar ₁ or Ar ₂ ),
L ₁ and L ₂ are each independently a direct bond, a substituted or unsubstituted C6~ C50 arylene group, or a substituted or unsubstituted C2~ C50 heteroarylene group,
m is an integer from 1 to 3).
According to claim 1,
Formula 1 is a compound for a capping layer represented by any one of Formulas 6 to 9:
[Formula 6]

[Formula 7]

[Formula 8]

[Formula 9]

(In Formulas 6 to 9,
Ar ₁ , L ₁ , L ₂ , X ₁ to X ₁₀ are the same as in Formula 1,
X ₁₁ , X ₁₃ and X ₁₄ are each independently C, O, S, N, CR or NR,
m is an integer from 1 to 3).
According to claim 1,
Any one of X ₁ to X ₄ is N, a compound for a capping layer.
According to claim 1,
Formula 1 is a compound for a capping layer represented by any one of Formulas 10 to 12:
[Formula 10]

[Formula 11]

[Formula 12]

(In Formulas 10 to 12,
Ar ₁ , Ar ₂ , L ₁ and L ₂ are the same as in Formula 1,
m is an integer from 1 to 3).
According to claim 1,
L ₁ to L ₃ are each independently a phenylene group, a biphenylene group, or a combination thereof.
According to claim 1,
Ar ₁ and Ar ₂ are each independently a condensed aryl group consisting of two rings or a condensed heteroaryl group consisting of two rings.
According to claim 1,
Ar ₁ and Ar ₂ are each independently selected from the group consisting of a benzofuran group, a benzothiophene group, an indolizine group, an imidazopyridine group, and a benzoxazole group.
According to claim 1,
The compound of Formula 1 is a compound for a capping layer, which is any one of the compounds represented by the following Formula:

An organic light-emitting device comprising a capping layer containing the compound for a capping layer according to any one of claims 1 to 13.
15. The method of claim 14,
The organic light emitting device,
a first electrode and a second electrode;
It includes one or more organic material layers interposed inside the first electrode and the second electrode,
The capping layer is an organic light-emitting device disposed outside any one or more of the first electrode and the second electrode.
15. The method of claim 14,
The capping layer has a thickness of 100 Å to 2,000 Å.
15. The method of claim 14,
The capping layer is an organic light emitting device having a refractive index of 2.25 or more at a wavelength of 450 nm.

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