CN117813282A

CN117813282A - Novel compound for capping layer and organic light-emitting element comprising same

Info

Publication number: CN117813282A
Application number: CN202280046030.9A
Authority: CN
Inventors: 咸昊完; 安贤哲; 金熙宙; 金东骏; 安慈恩; 权桐热; 李成圭; 李太振; 李宝罗; 朴英珑; 吴一洙; 李大雄; 任玹庭; 赵一薰
Original assignee: Dongjin Semichem Co Ltd; Samsung Display Co Ltd
Current assignee: Dongjin Semichem Co Ltd; Samsung Display Co Ltd
Priority date: 2021-06-30
Filing date: 2022-06-30
Publication date: 2024-04-02

Abstract

The present invention provides a novel compound for a coating layer and an organic light-emitting element containing the same.

Description

Novel compound for capping layer and organic light-emitting element comprising same

Technical Field

The present invention relates to a compound for a cap layer and an organic light-emitting element including the compound for a cap layer.

Background

Materials used as the organic layer in the organic light emitting diode can be broadly classified into a light emitting material, a hole injecting material, a hole transporting material, an electron injecting material, and the like according to their functions.

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

A general organic light emitting device may have a structure in which an anode is formed on a substrate, and a hole transporting layer, a light emitting layer, an electron transporting layer, and a cathode are sequentially formed on the anode. Wherein the hole transport layer, the light emitting layer and the electron transport layer are organic thin films composed of organic compounds.

The driving principle of the organic light emitting element structured as described above is as follows.

When a voltage is applied between the anode and the cathode, holes injected from the anode will move to the light emitting layer via the hole transporting layer, while electrons injected from the cathode will move to the light emitting layer via the electron transporting layer. The holes and electrons will recombine at the light emitting layer and generate excitons.

Light will be generated during the transition of the exciton from the excited state to the ground state. The efficiency of an organic light emitting element can be generally classified into internal light emitting efficiency and external light emitting efficiency. The internal light emission efficiency is related to the efficiency of generating excitons and achieving light conversion in an organic layer such as a hole transporting layer, a light emitting layer, and an electron transporting layer interposed between a first electrode and a second electrode, and theoretically, the internal light emission efficiency of fluorescence is 25% and phosphorescence is 100%.

Further, the external light emission efficiency refers to the efficiency with which light generated in the organic layer is extracted to the outside of the organic light emitting element, and it has been known that about 20% of the internal light emission efficiency can be extracted to the outside in general. As the method of increasing the light extraction efficiency, various organic compounds having a refractive index of 1.7 or more are applied to the cover layer in order to prevent the loss of light irradiated to the outside due to total reflection, and in order to further increase the external light emission efficiency of the organic light emitting element, efforts have been made to develop an organic light emitting element having a composite layer structure including a cover layer having a high refractive index and a cover layer having a low refractive index. As a low refractive index coating material, liF has been commercialized, but the inorganic compound has problems of high deposition temperature and poor engineering, so there has been continuous effort to replace it with an organic compound. The presently known substances having a low refractive index include boron complex compounds, but the boron complex compounds may cause a problem of a decrease in the service life of the organic light emitting element due to insufficient stability thereof. Accordingly, efforts have been made to develop organic capping materials that can ensure excellent stability of compounds while maintaining a low refractive index.

Disclosure of Invention

Technical problem to be solved

The purpose of the present invention is to provide a compound for a coating layer, which can form a lower refractive index, particularly can maintain a wider band gap, by using an amine structure having a cycloalkyl group or a heterocyclic group, and can thereby ensure a lower attenuation coefficient even in a short wavelength range and thereby realize a lower refractive index, and an organic light-emitting element comprising the compound for a coating layer.

Further, an object of the present invention is to provide a compound for a cap layer, which has a lower refractive index by containing a cycloalkyl group or a heterocyclic group having a lower polarization ratio, and thus can very effectively improve the efficiency and color purity of an organic light-emitting element, and an organic light-emitting element containing the compound for a light-emitting layer.

Further, the present invention has an object to provide a compound for a cap layer, which has high thermal stability by having structural characteristics and at the same time has excellent thin film alignment properties, and thus can improve stability under external oxygen, air, moisture and other pollution conditions, and thus can very effectively improve the service life of an organic light emitting element when applied to a cap layer, and an organic light emitting element comprising the compound for a cap layer.

Next, the problems and additional problems described above will be described in detail.

Means for solving the problems

To solve the above-described problems, in one embodiment of the present invention,

provided is a compound for a cover layer represented by the following chemical formula 1:

< chemical formula 1>

In the chemical formula 1 described above, a compound having the formula,

cy is substituted or unsubstitutedCycloalkyl, or substituted or unsubstituted +.>Is a heterocyclic group of (a) and (b),

l is a direct bond, a substituted or unsubstituted C1-C50 alkylene group, a substituted or unsubstituted C2-C50 alkenylene group, a substituted or unsubstituted C1-C50 alkyleneoxy group, an ether group, a substituted or unsubstituted C1-C50 ester group, a substituted or unsubstituted C1-C50 mercapto group, a thioether group, a substituted or unsubstituted C1-C50 thioester group, a substituted or unsubstituted C1-C50 carbonyl group, a substituted or unsubstituted-C (X1) NR3-, a substituted or unsubstituted-NR 4C (X2) -, or a combination thereof,

l1 and L2 are each independently a direct bond, a substituted or unsubstituted C1-C50 alkylene group, a substituted or unsubstituted C2-C50 alkenylene group, a substituted or unsubstituted C1-C50 alkyleneoxy group, an ether group, a substituted or unsubstituted C1-C50 ester group, a substituted or unsubstituted C1-C50 mercapto group, a thioether group, a substituted or unsubstituted C1-C50 thioester group, a substituted or unsubstituted C1-C50 carbonyl, substituted or unsubstituted-C (X1) NR3-, substituted or unsubstituted-NR 4C (X2) -, substituted or unsubstituted-NR-, substituted or unsubstituted C3-C50 cycloalkylene or a substituted or unsubstituted C1 to C50 heterocyclylene, a substituted or unsubstituted C3 to C50 arylene, or a substituted or unsubstituted C2 to C50 heteroarylene, or a combination thereof, but excludes the carbazolyl group,

X1 and X2 are each independently O, S, se, te, NR or CR6R7,

r1 to R7 are each independently hydrogen, deuterium, halogen, nitro, nitrile, hydroxyl, thiol, substituted or unsubstituted amino, substituted or unsubstituted C1-C50 alkyl, substituted or unsubstituted C2-C50 alkenyl, substituted or unsubstituted C1-C50 alkoxy, substituted or unsubstituted C1-C50 thiol, substituted or unsubstituted silyl, substituted or unsubstituted C3-C50 cycloalkyl, substituted or unsubstituted C3-C50 cycloalkenyl, substituted or unsubstituted C1-C50 heterocyclyl, substituted or unsubstituted C3-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl, adjacent ones of R1 to R7 may be bound to each other to form or not form a ring, but carbazolyl is excluded.

In addition, in one embodiment of the present invention,

an organic light-emitting element containing the compound for a cover layer as described above is provided.

Effects of the invention

According to the compound for a cladding layer of one embodiment of the present invention, by using an amine structure of a cycloalkyl group or a heterocyclic group, a lower refractive index can be formed, and particularly a wider band gap can be maintained, so that a lower attenuation coefficient can be ensured even in a short wavelength range and thereby a lower refractive index can be achieved.

In addition, by having a lower refractive index by using a cycloalkyl group or a heterocyclic group having a lower polarization ratio, the efficiency and color purity of the organic light-emitting element can be improved very effectively.

In addition, since the organic light emitting device has high thermal stability and excellent thin film alignment due to structural characteristics, stability under external oxygen, air, moisture and other pollution conditions can be improved, and thus the service life of the organic light emitting device can be very effectively improved when the organic light emitting device is applied to a cover layer.

Next, the effects and additional effects described above will be described in detail.

Drawings

Fig. 1 is a schematic cross-sectional view illustrating the constitution of an organic light emitting element according to one embodiment of the present invention.

Description of the reference numerals

100: substrate board

200: hole injection layer

300: hole transport layer

400: light-emitting layer

500: electron transport layer

600: electron injection layer

1000: first electrode

2000: second electrode

3000: cover layer

Detailed Description

Before explaining the present invention in detail, it is to be understood that the terminology used in the description is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention, which is limited only by the scope of the appended claims. Unless otherwise specifically stated, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art.

Throughout this specification and the claims, unless explicitly stated otherwise, the term "comprising" (comprise, comprises, comprising) is intended to exclude the presence of a stated object, step or series of objects and steps, and does not exclude the presence of any other object, step or series of objects or steps.

Throughout the present specification and claims, the term "aryl" is meant to include, for example, phenyl, benzyl, naphthyl, biphenyl, terphenyl, fluorenyl, phenanthryl, triphenylene, phenylene,Group, fluoranthenyl, benzofluorenyl, benzotriphenylene, benzo +.>The "heteroaryl group" means an aromatic ring having 5 to 50 carbon atoms and containing at least one hetero element, such as an aromatic ring group including a pyrrolyl group, a pyrazinyl group, a pyridyl group, an indolyl group, an isoindolyl group, a furyl group, a benzofuryl group, an isobenzofuryl group, a dibenzofuryl group, a benzothienyl group, a dibenzothienyl group, a quinolyl group, an isoquinolyl group, a quinoxalinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a thienyl group, and a heterocyclic group including a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a triazine ring, an indole ring, a quinoline ring, an acridine ring, a pyrrolidine ring, a dioxane ring, a piperidine ring, a morpholine ring, a piperazine ring, a carbazole ring, a furan ring, a thiophene ring, an oxazole ring, an oxadiazole ring, a benzofuran ring, a thiazole ring, a thiadiazole ring, a benzothiophene ring, a benzotriazole ring, an imidazole ring, a benzimidazole ring, a pyran ring, and a dibenzofuran ring.

In addition, arx (where x is an integer) in the formula represents a substituted or substituted C6 to C50 aryl group, or a substituted or unsubstituted C2 to C50 heteroaryl group, lx (where x is an integer) represents a directly bonded, substituted or unsubstituted C6 to C50 arylene group, or a substituted or unsubstituted C2 to C50 heteroarylene group, unless explicitly defined otherwise, and Rx (where x is an integer) represents hydrogen, deuterium, halogen, nitro, nitrile, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C2 to C30 alkenyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C1 to C30 mercapto group, a substituted or unsubstituted C6 to C50 aryl group, or a substituted or unsubstituted C2 to C50 heteroaryl group, unless explicitly defined otherwise.

Throughout the present specification and claims, the term "substituted or unsubstituted" may refer to any one or more of the groups selected from the group consisting of deuterium, halogen, amino, cyano, nitrile, nitro, nitroso, sulfamoyl, isothiocyanate, thiocyanate, carboxyl, or C1-C30 alkyl, C1-C30 alkylsulfinyl, C1-C30 alkylsulfonyl, C1-C30 alkylsulfanyl, C1-C12 fluoroalkyl, C2-C30 alkenyl, C1-C30 alkoxy, C1-C12N-alkylamino, C2-C20N, N-dialkylamino, substituted or unsubstituted C1-C30 mercapto, C1-C6N-alkylsulfamoyl, C2-C12N, N-dialkylsulfamoyl, C0-C30 silyl, C3-C20 cycloalkyl, C3-C20 heterocycloalkyl, C6-C50 aryl, and C3-C50 heteroaryl, and the like. Furthermore, throughout the specification of the present application, the same symbols may have the same meaning unless explicitly stated otherwise.

Furthermore, various embodiments of the invention may be combined with other certain embodiments, unless explicitly stated to the contrary. Next, embodiments of the present invention and effects thereof will be described.

The organic light emitting element according to an embodiment of the present invention may be an organic light emitting element including a capping layer. Specifically, the organic light-emitting device may include a first electrode, a second electrode, one or more organic layers disposed inside the first electrode and the second electrode, and a coating layer disposed outside one or more of the first electrode and the second electrode and containing the coating compound of the present invention.

As a specific example of the compound for a cover layer of the present invention, a compound for a cover layer represented by the following chemical formula 1 may be contained.

< chemical formula 1>

In the chemical formula 1 described above, a compound having the formula,

cy is a substituted or unsubstituted C3-C20 cycloalkyl group, or a substituted or unsubstituted C1-C20 heterocyclyl group,

l is a direct bond, a substituted or unsubstituted C1-C50 alkylene group, a substituted or unsubstituted C2-C50 alkenylene group, a substituted or unsubstituted C1-C50 alkyleneoxy group, an ether group, a substituted or unsubstituted C1-C50 ester group, a substituted or unsubstituted C1-C50 mercapto group, a thioether group, a substituted or unsubstituted C1-C50 thioester group, a substituted or unsubstituted C1-C50 carbonyl group, a substituted or unsubstituted-C (X1) NR3-, a substituted or unsubstituted-NR 4C (X2) -, or a combination thereof, more specifically, it may be a combination of three or less thereof.

L1 and L2 are each independently a direct bond, a substituted or unsubstituted C1-C50 alkylene group, a substituted or unsubstituted C2-C50 alkenylene group, a substituted or unsubstituted C1-C50 alkyleneoxy group, an ether group, a substituted or unsubstituted C1-C50 ester group, a substituted or unsubstituted C1-C50 mercapto group, a thioether group, substituted or unsubstituted C1-C50 thioester group, substituted or unsubstituted C1-C50 carbonyl group, substituted or unsubstituted-C (X1) NR 3-; substituted or unsubstituted-NR 4C (X2) -, substituted or unsubstituted-NR-, substituted or unsubstituted C3-C50 cycloalkylene, or substituted or unsubstitutedA substituted or unsubstituted C3 to C50 arylene group, or a substituted or unsubstituted C2 to C50 heteroarylene group, or a combination thereof, more specifically, it may be a combination of three or less thereof, but excludes carbazolyl groups.

X1 and X2 are each independently O, S, se, te, NR or CR6R7,

In particular, the Cy may be substituted or unsubstitutedCycloalkyl groups of (a).

Further, in particular, L2 may be a direct bond and R2 may be hydrogen.

Further, in particular, L may be a direct bond, a carbonyl group, -CH2CO-, an ester group, a thioester group, an ether group, or a thioether group, or a combination of three or less of these groups.

As a specific example compound of the compound for a cover layer of the present invention, the chemical formula 1 may contain compounds for a cover layer represented by the following chemical formulas 2 to 5.

< chemical formula 2>

< chemical formula 3>

< chemical formula 4>

< chemical formula 5>

In the chemical formulas 2 to 5,

the same symbols as those of the chemical formula 1 are defined as those of the chemical formula 1.

The compound for a cover layer of the present invention represented by chemical formulas 2 to 5 can ensure excellent chemical stability and thermal stability while maintaining a low refractive index through an amide group.

In the chemical formula 1, one or more of R1 and R2 may be a substituted or unsubstituted C3 to C50 cycloalkyl group or a substituted or unsubstituted C1 to C50 heterocyclic group. Thereby, a low refractive index can be achieved by reducing the polarization ratio.

Specifically, all of R1 and R2 may be a substituted or unsubstituted C3 to C50 cycloalkyl group or a substituted or unsubstituted C1 to C50 heterocycloalkyl group. Thereby, the molecular weight can be increased and the thermal stability can be improved, which can effectively improve the life.

In addition, in the chemical formula 1, L1 may be a direct bond, R2 may be hydrogen, and R2 may be a substituted or unsubstituted C3 to C50 cycloalkyl group, or a substituted or unsubstituted C1 to C50 heterocyclic group. Thereby, efficiency can be further improved by minimizing the volume characteristics of the molecules and further reducing the polarizability.

In the chemical formulas 1 to 5, the Cy may be a substituted C3 to C20 cycloalkyl group, or a substituted C1 to C20 heterocyclic group. Thereby, the thermal stability can be further improved, while also achieving a low refractive index by reducing the polarization ratio.

The substituents of Cy are not limited, but may be each independently selected from the group consisting of a hydroxyl group, a thiol group, an amino group, a C1 to C30 alkyl group, a C1 to C30 alkoxy group, a C1 to C30 mercapto group, a silyl group, a halogen group, a C3 to C30 cycloalkyl group, a C1 to C30 heterocyclic group, and combinations thereof. By having substituents as described above, a lower refractive index can be maintained, while also having higher thermal stability.

Further, in the chemical formulas 1 to 5, the Cy may be selected from the following chemical formulas a-1 to a-21.

In the chemical structural formulae A-1 to A-21, each W is independently methyl, ethyl, tert-butyl, cyclohexyl, adamantyl, dihydro-amino, dimethylamino, hydroxy, methoxy, thiol, methylthio, fluoro, trifluoromethyl or trimethylsilyl,

n is each independently an integer of 0 to 10, specifically an integer of 0 to 4,

* Representing the binding sites.

In addition, in the chemical formula 1, one or more of-L1-R1 and-L2-R2 may each be independently selected from the following chemical formulas B-1 to B-47.

/>

In the chemical structural formula, each W1 is independently methyl, ethyl, tertiary butyl, cyclohexyl, adamantyl, dihydro-amino, dimethylamino, hydroxy, methoxy, thiol, methylthio, nitrile, nitro, fluoro, trifluoromethyl or trimethylsilyl,

* Representing the binding sites.

Furthermore, one or more of-L1-R1 and-L2-R2 may each independently adopt a chemical structural formula of a form in which the-CO structure in the chemical structural formulae B-1 to B-47 is substituted by-Z-, which is-O-, -S-, -CH2CO-, -CH2-NH-CO-, -O-NH-CO-, -S-NH-CO-, -CO-NH-CO-, -NH-C (=nme) -, -NHC (=chme) -, -NHCOO-, -NH-, -CO-NH-, -OCONH-, -SCONH-, -CO-NH-, -CS-, -C (=nh) -, -C (=nme) -, -C (=chme) -, -SCO-, -OCO-, -CH2-, or "".

In addition, in the compound for a cover layer represented by chemical formula 1, when the refractive index is measured in a thickness range of 20nm to 100nm, the refractive index at a wavelength of 450nm may be a low refractive index of 1.55 or less. Specifically, the refractive index at a wavelength of 450nm may be 1.50 or less, and more specifically, may be a low refractive index of 1.47 or less.

Further, the chemical formula 1 may be a compound for a cover layer represented by any one of the following compounds. The following compounds are merely illustrative of the present invention, and the present invention is not limited thereto.

/>

An example of the compound of the present invention can be synthesized by the following general reaction scheme.

< reaction No. 1>

/>

(h is a halogen element)

In another embodiment of the present invention, there is provided an organic light-emitting element as a covering layer including the compound for a covering layer as described above.

Next, an organic light emitting element according to one embodiment of the present invention will be described in detail.

In one embodiment of the present invention, the organic light-emitting element may include a first electrode, a second electrode, one or more organic layers interposed between the first electrode and the second electrode, and a cover layer, and the cover layer may be disposed outside one or more of the first electrode and the second electrode.

Specifically, one of the two side surfaces of the first electrode or the second electrode, which is adjacent to the organic layer interposed between the first electrode and the second electrode, is referred to as an inner side and the other side not adjacent to the organic layer is referred to as an outer side. That is, when the capping layer is disposed outside the first electrode, the first electrode will be interposed between the capping layer and the organic layer, and when the capping layer is disposed outside the second electrode, the second electrode will be interposed between the capping layer and the organic layer.

In addition, in an embodiment of the present invention, the inner sides of the first electrode and the second electrode of the organic light emitting device may be interposed with one or more organic layers, and a cover layer may be formed outside one or more of the first electrode and the second electrode. That is, the cover layer may be formed on the outer side of the first electrode at the same time as the outer side of the second electrode, or may be formed on the outer side of the first electrode only or the outer side of the second electrode.

In this case, the covering layer may contain the covering layer compound according to the present invention, may contain the covering layer compound according to the present invention alone or two or more kinds, or may contain a known compound at the same time.

The thickness of the cover layer may beTo->

In addition, the cover layer may have a composite cover layer structure in which a first cover layer having a relatively low refractive index and a second cover layer having a higher refractive index than the second cover layer are laminated, and in the case described above, the compound for a cover layer according to the present invention may be contained in the first cover layer. The order of stacking the first cover layer and the second cover layer is not particularly limited, and the first cover layer may be disposed outside the second cover layer, or the second cover layer may be disposed outside the first cover layer. As a specific example, the second cover layer may be interposed between the first cover layer and the first electrode or the second electrode, and in particular, the second cover layer may be a structure in contact with the first cover layer and the first electrode or the first cover layer and the second electrode.

In addition, a multilayer structure in which a plurality of first cover layers and a plurality of second cover layers are stacked may be employed. In the above case, the first cover layer and the second cover layer may be alternately stacked, and the stacking order is not limited to the above order, and the first cover layer may be arranged outside the second cover layer, or the second cover layer may be arranged outside the first cover layer.

Further, the refractive index of the first cover layer at a wavelength of 450nm may be 1.55 or less, specifically 1.50 or less, and more specifically 1.47 or less. The refractive index of the second cover layer at a wavelength of 450nm may be 2.10 or more, specifically 2.25 or more, more specifically 2.30 or more, and the difference between the refractive index of the first cover layer and the refractive index of the second cover layer at a wavelength of 450nm may be in the range of 0.2 to 1.2, more specifically 0.4 to 1.2. In the case where the difference in refractive index is less than 0.2 or exceeds 1.2, there may be caused a problem in that the light extraction efficiency is lowered.

The total thickness of the first cover layer may beTo->Within (2), and the total thickness of the second cover layer may be within +.>To->Is within the scope of (2).

The refractive index of the cover layer may be in a gradient form. The gradient of the refractive index may be such that the refractive index gradually decreases as it approaches the outside, or such that the refractive index gradually increases as it approaches the outside. For this purpose, the coating layer may be formed by gradually changing the concentration of the compound for coating layer according to the present invention, thereby realizing a gradient of refractive index in the coating layer.

The organic layer may include a hole transporting layer, a light emitting layer, and an electron transporting layer which generally constitute a light emitting portion, but is not limited thereto.

Specifically, the organic light emitting element according to one embodiment of the present invention may include one or more organic layers constituting a light emitting section such as a Hole Injection Layer (HIL), a Hole Transport Layer (HTL), an emission layer (EML), an Electron Transport Layer (ETL), and an Electron Injection Layer (EIL) between a first electrode (anode) and a second electrode (cathode). Optionally, a hole blocking layer (HBL, not shown) or an electron transport auxiliary layer may be further included between the light emitting layer (EML) and the Electron Transport Layer (ETL), and an electron blocking layer (EBL, not shown) may be further included between the Hole Transport Layer (HTL) and the light emitting layer (EML).

Fig. 1 is a sectional view schematically illustrating the constitution of an organic light emitting element according to an embodiment of the present invention. An organic light emitting element according to one embodiment of the present invention may be manufactured in a structure as shown in fig. 1.

As shown in fig. 1, the organic light emitting element may have a structure in which 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, an electron injection layer 600, a second electrode 2000, and a capping layer 3000 are sequentially stacked from bottom to top. The cover layer 300 may be formed by stacking the first cover layer and the second cover layer, as described above, although not shown. The third coating layer having a refractive index different from that of the first coating layer and the second coating layer may be additionally laminated, and is not particularly limited. The refractive index of the cover layer may be in a gradient form. The gradient of the refractive index may be such that the refractive index gradually decreases as it approaches the outside, or such that the refractive index gradually increases as it approaches the outside.

Among them, the substrate 100 may be a substrate commonly used in an organic light emitting element, and particularly, a transparent glass substrate or a flexible plastic substrate excellent in mechanical strength, thermal stability, transparency, surface smoothness, handling convenience, and water repellency may be used.

Further, the first electrode 1000 is used as a hole injection electrode for injecting holes in the organic light emitting element. The first electrode 1000 is manufactured using a material having a work function as low as possible to achieve hole injection, and may be formed using a transparent material such as Indium Tin Oxide (ITO), indium Zinc Oxide (IZO), or graphene (graphene).

Meanwhile, the hole injection layer 200 may be formed by depositing a hole injection layer material on the upper portion of the first electrode 1000 using a method such as a vacuum deposition method, a spin coating method, a casting method, a Langmuir-Blodgett (LB) method, or the like. When the hole injection layer 200 is formed by the vacuum deposition method, the deposition conditions thereof will vary depending on the compound used as the material of the hole injection layer 200, the desired structure and thermal characteristics of the hole injection layer 200, and may be generally at a deposition temperature of 50 to 500 ℃, a vacuum level of 10-8 to 10-3 Torr (torr), 0.01 to Deposition rate of>The layer thickness to 5 μm is suitably selected. Further, a charge generation layer may be additionally deposited on the surface of the hole injection layer 200 as needed. As the charge generation layer material, a general material can be used, for example, hexacyano group can be usedHexaazatriphenylene (HATCN).

In addition, the hole transporting layer 300 may be formed by depositing a hole transporting layer material on the hole injecting layer 200 by a method such as a vacuum deposition method, a spin coating method, a casting method, a langmuir-blodgene (LB) method, or the like. In forming the hole transport layer 300 by the vacuum deposition method, the deposition conditions thereof will vary depending on the compound used, but are generally selected within the range of conditions almost identical to those of the formation of the hole injection layer 200. The hole transport layer 300 may be formed using a known compound. The hole transport layer 300 may be one or more layers as described above, and although not shown in fig. 1, a light-emitting auxiliary layer may be additionally formed on the hole transport layer 300.

Meanwhile, the light emitting layer 400 may be formed by depositing a light emitting layer material on the hole transporting layer 300 or the light emitting auxiliary layer using a method such as a vacuum deposition method, a spin coating method, a casting method, a langmuir-blodgene (LB) method, or the like. When the light-emitting layer 400 is formed by the vacuum deposition method, the deposition conditions thereof will vary depending on the compound used, but are generally selected within the range of conditions almost identical to those for the formation of the hole injection layer 200. As the material of the light-emitting layer, a known compound may be used as a host or a dopant. The dopant is not limited, and a phosphorescent or fluorescent dopant may be used together to form the light emitting layer. As an example, BD142 (N6, N12-bis (3, 4-dimethylphenyl) -N6, N12-dicarboxyl-6, 12-diamine) may be used as the fluorescent dopant, while red phosphorescent dopant of UDC company, i.e., RD61, etc., may be used as the phosphorescent dopant for co-vacuum deposition (doping) using Ir (ppy) 3 (tris (2-phenylpyridine) iridium), blue fluorescent dopant, i.e., F2Irpic (bis [4, 6-difluorophenyl) -pyridinyl-N, C2' ] picolinic acid iridium (III). The doping concentration of the dopant is not particularly limited, and it is preferable to dope 0.01 part by weight of the dopant to 100 parts by weight of the host. When the content of the dopant is less than 0.01 parts by weight, there is a possibility that the color development may not be smooth due to insufficient doping amount, whereas when it exceeds 15 parts by weight, there is a possibility that the efficiency may be drastically reduced due to the concentration extinction phenomenon.

When phosphorescent dopants are used in combination in the light-emitting layer material, a hole blocking material (HBL) may be additionally laminated on the light-emitting layer 400 by a vacuum deposition method or a spin coating method in order to prevent a phenomenon in which triplet excitons or holes diffuse into the electron transport layer 500. The usable hole blocking material is not particularly limited, and any known material may be selected and used. For example, oxadiazole derivatives, benzotriazole derivatives, phenanthroline derivatives, hole blocking materials described in Japanese patent application laid-open No. 11-329734 (A1), and the like can be used, and among them, bis (8-hydroxy-2-methylquinoline) - (4-phenylphenoxy) aluminum (Balq) and phenanthroline (phenanthroline) compounds (for example, BCP (bathocuproine) from UDC) and the like are most typically included. The light emitting layer 400 of the present invention as described above may include one or more blue light emitting layers.

In addition, the electron transport layer 500 is formed on the upper portion of 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, or the like. The deposition conditions of the electron transport layer 500 will vary depending on the compound used, but are generally selected within the range of conditions that are almost identical to those of the formation of the hole injection layer 200. As a generally known substance, quinoline derivatives, in particular tris (8-hydroxyquinoline) aluminum (Alq 3) or ET4 (6, 6'- (3, 4-dicarboxyl-1, 1-dimethyl-1H-silanol-2, 5-diyl) bis-2, 2' -bipyridine) can be used.

Further, the electron injection layer 600 may be formed by depositing an electron injection layer material on the upper portion of the electron transport layer 500, and may be formed by a method such as a vacuum deposition method, a spin coating method, a casting method, or the like. As the electron injection layer material, a known material, for example, liF, naCl, csF, li2O, baO, or the like can be used.

Meanwhile, the second electrode 2000 is used as an electron injection electrode, and may be formed on the upper portion of the electron injection layer 600 by a vacuum deposition method, a sputtering method, or the like. As a material of the second electrode 2000, various metals may be used. As concrete facts, substances such as lithium (Li), aluminum (Al), gold (Au), silver (Ag), magnesium (Mg), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag) and the like can be used, but are not limited thereto. In addition, in order to obtain a front-side light emitting element, a transmissive electron injection electrode using ITO or IZO may be used.

The organic light-emitting element of the present invention may be an organic light-emitting element having not only 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, the second electrode 2000, and the cover layer 3000 described above, but also an organic light-emitting element having various structures, or an intermediate layer including one or two layers may be added as necessary.

Further, the thickness of each organic layer formed by the present invention may be adjusted according to a desired degree, and may be specifically 1 to 1,000nm, and more specifically 1 to 150nm.

As shown in fig. 1, the cover layer 3000 may be formed on the outer side surface of the first electrode 1000 where the hole injection layer 200 is not formed. In addition, the outer side surfaces of the electron injection layer 600 may not be formed in both side surfaces of the second electrode 2000, but are not limited thereto. The cover layer 3000 as described above may be formed by deposition engineering, and the thickness of the cover layer 3000 may be 100 toMore specifically 300 to +.>By the thickness adjustment method described above, the transmittance of the cover layer 3000 can be prevented from being lowered.

Although not shown in fig. 1, in an embodiment of the present invention, an organic layer for performing various functions may be additionally formed between the cover layer 3000 and the first electrode 1000 or between the cover layer 3000 and the second electrode 2000. Alternatively, an organic layer having a plurality of functions may be additionally formed on the upper portion (outer surface) of the cover layer 3000, and one or more functional layers may be interposed between the cover layers 3000.

Next, the present invention will be described in more detail by way of examples of synthesis of the compound according to one embodiment of the present invention and examples of the organic light emitting element. The following synthesis examples and examples are merely illustrative of the present invention, and the scope of the present invention is not limited to the following examples.

Synthesis example 1: synthesis of Compound 90

In a round-bottomed flask, after 5.0g of adamantane-1-carbonyl chloride (adamantane-1-carbonyl chloride) and 13.9g of triethylamine (triethylimine) were dissolved in 100ml of 1,4-dioxane (1, 4-dioxane), 5.3g of 3, 5-di-tert-butylcyclohexylamine (3, 5-di-tert-butylcyclohexane) dissolved in 50ml of 1,4-dioxane was slowly added dropwise, followed by stirring at 60℃for 5 hours and stirring at ordinary temperature for 24 hours. The reaction was completed by slowly dropping the reaction solution into 400ml of concentrated hydrochloric acid solution. The precipitated solid was subjected to filtration under reduced pressure and then recrystallized, whereby 4.6g of compound 90 was obtained (yield: 85%).

m/z:373.3345(100.0％)、374.3378(27.0％)、375.3412(3.5％)

Synthesis example 2: synthesis of Compound 134

The procedure was carried out in the same manner as in Synthesis example 1, except that 3,5-di-tert-butylaniline (3, 5-di-tert-butyl laniline) was used instead of 3, 5-di-tert-butylcyclohexylamine (3, 5-di-tert-butyloxycyclohexamine) to synthesize compound 134. (yield was 85%)

m/z:367.2875(100.0％)、368.2909(27.0％)、369.2942(3.5％)

Synthesis example 3: synthesis of Compound 169

The same procedure as in Synthesis example 1 was conducted, using 1-adamantanamine hydrochloride (1-adamantanamine hydrochloride) instead of 3, 5-di-tert-butylcyclohexylamine (3, 5-di-tert-butylycyclohexamine), to synthesize compound 169. (yield was 85%)

m/z:313.2406(100.0％)、314.2439(22.7％)、315.2473(2.5％)

Synthesis example 4: synthesis of Compound 180

The procedure of Synthesis example 1 was followed, using 5-Dimethyladamantane-1-carbonyl chloride (5-dimethyllamantane-1-carbonyl chloride) and memantine (memantine) in place of 4-tert-butylcyclohexanecarboxychloride (4-tert-butylcyclohexanecarbonyl chloride) and 1, 4-phenylenediamine (benzene-1, 4-diamine), to synthesize compound 180. (yield 79%)

m/z:369.3032(100.0％)、370.3065(27.0％)、371.3099(3.5％)

Synthesis example 5: synthesis of Compound 204

The procedure of Synthesis example 1 was followed, using bis (4-tert-butylcyclohexyl) amine instead of 3, 5-di-tert-butylcyclohexylamine (3, 5-di-tert-butylcyclohexyl) amine), to synthesize compound 204. (yield 80%)

m/z:455.4127(100.0％)、456.4161(33.5％)、457.4194(5.4％)

Synthesis examples 6 to 20

The same procedure as in Synthesis example 1 was followed, except that starting material 1 and starting material 2 of tables 1 to 3 below were used in place of adamantane-1-carbonyl chloride (adamantane-1-carbonyl chloride) and 3, 5-di-tert-butylcyclohexylamine (3, 5-di-tert-butyloxycyclohexylamine) to synthesize compounds.

TABLE 1

TABLE 2

TABLE 3 Table 3

Manufacture of organic light emitting devices

Fig. 1 is a schematic diagram illustrating a structure of a general organic light emitting element, and as an example of the present invention, the organic light emitting element shown in fig. 1 is manufactured. Specifically, the organic light emitting element manufactured is formed by sequentially stacking, in order from bottom to top, an anode (hole injection electrode) 1000/hole injection layer 200/hole transport layer 300/light emitting layer 400/electron transport layer 500/electron injection layer 600/cathode (electron injection electrode) 2000/capping layer 3000. The cover layer 3000 may be a multi-layer structure formed by compounding the first cover layer and the second cover layer as described above.

In the case of manufacturing the organic light emitting element, the substrate 10 may be a transparent glass substrate or a flexible plastic panel.

The hole injection electrode 1000 is used as an anode for injecting holes into an organic light emitting element. A substance having a work function as low as possible is used to inject holes, and may be formed of a transparent material such as Indium Tin Oxide (ITO), indium Zinc Oxide (IZO), or graphene (graphene).

The substances shown in table 4 below are applied to 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, and the high refractive index coating layer.

Further, a cathode 2000 for injecting electrons is formed above the electron injection layer 600. As the cathode, various metals can be used. As specific examples, substances such as aluminum, gold, silver, magnesium-silver alloy, and the like are included.

TABLE 4 Table 4

Example 1

An Indium Tin Oxide (ITO) substrate having a silver (Ag) -containing reflective layer formed thereon was washed with distilled water ultrasonic waves. After the distilled water washing is completed, ultrasonic washing is performed using solvents such as isopropyl alcohol, acetone, and methanol, and drying is performed. Next, NDP9 was doped with 3 wt% in HT01 as a hole injection layer on an Indium Tin Oxide (ITO) substrate, respectivelyIs deposited with a thickness of HT01 +.>After deposition of the thickness of (2) the dopant BD01 is doped as a light-emitting layer in the host BH01 at 3 wt% and +.>Is deposited by the thickness of (a). Next, a mixture of ET01 and Liq (1:1, wt./wt.) was used as the electron transport layer to +.>Thickness is deposited, then LiF is deposited by +.>Is deposited to form an electron injection layer. Next, a cathode is formed by deposition of MgAg at a thickness of 15nm, and CPM01 is then deposited as a high refractive coating layer over the cathode >After deposition of the thickness of (2) the compound produced by synthesis example 1 was treated with +.>Is deposited by the thickness of (a). An organic light emitting element was manufactured by encapsulating (encapsulating) the element in a glove box.

Examples 2 to 20

The same procedure as in example 1 was followed, wherein low refractive index coating layers were formed by using the compound films produced in Synthesis examples 2 to 20, respectively, to produce organic light-emitting devices.

Comparative examples 1 to 4

An organic light-emitting element was manufactured in the same manner as in example 1, in which a low-refractive coating layer was formed by using comparative compounds 1 to 4 shown in table 5 below.

TABLE 5

Test example 1 evaluation of organic light-emitting element performance

The performance of the organic light emitting element was evaluated by applying a voltage to a positive 2400 source measurement unit (Kiethley 2400 source measurement unit) to inject electrons and holes and measuring the brightness when light was emitted using a Konica Minolta spectroradiometer (CS-2000), thereby measuring the current density and brightness with respect to the applied voltage by examples 1 to 5, 14 to 17, 20 and comparative examples 1 to 4 under the atmospheric pressure conditions, and the results are shown in table 6 below.

TABLE 6

	Op.V	mA/cm2	Cd/A	CIEx	CIEy	LT97
							Example 1	3.50	10	11.03	0.139	0.042	153
Example 2	3.50	10	9.75	0.139	0.044	147
							Example 3	3.50	10	10.35	0.140	0.043	168
Example 4	3.50	10	10.37	0.140	0.043	175
							Example 5	3.50	10	10.98	0.139	0.042	165
Example 14	3.50	10	11.06	0.139	0.042	162
							Example 15	3.50	10	11.05	0.139	0.042	162
Example 16	3.50	10	11.03	0.139	0.042	157
							Example 17	3.50	10	11.00	0.139	0.042	150
Example 20	3.50	10	10.96	0.139	0.042	149
							Comparative example 1	3.53	10	6.36	0.134	0.054	63
Comparative example 2	3.51	10	8.15	0.135	0.047	140
							Comparative example 3	3.52	10	7.35	0.137	0.051	115
Comparative example 4	3.51	10	8.33	0.137	0.047	51

As can be seen from a comparison of examples of the present invention with comparative examples, the present invention can have a low refractive index by employing an amine structure of cycloalkyl or heterocyclyl and a lower polarizability substituent, whereby excellent film formation and thermal stability can be ensured, and thus an organic light emitting element of high sirtuin purity, high efficiency and long service life can be realized. In particular, comparing the examples of the present invention, it can be found that when comparing example 1 and example 2, if they have cycloalkyl groups other than Cy, they have lower refractive indexes and can effectively improve efficiency.

In addition, when comparing example 1 and example 3 and example 4, it is effective for improving the service life when it additionally has adamantane of a rigid structure, and it has excellent thermal stability when it additionally has a substituent, and is more effective for improving the service life. Finally, in comparing example 1 and example 5, if it has cycloalkyl groups other than Cy, it has a lower refractive index and excellent thermal stability and can effectively improve efficiency and service life.

< test example 2> evaluation of refractive index

Deposited films having a thickness of 30nm were produced on a silicon substrate by a vacuum deposition apparatus using the compounds of Synthesis examples 1 to 5 and comparative compounds 1 to 4, respectively, and then refractive indexes at a wavelength of 450nm were measured by an ellipsometer apparatus (J.A. Woollam Co.Inc., M-2000X). The results are shown in Table 7 below.

TABLE 7

As described in table 7, it was confirmed that the compounds according to the present invention exhibited a lower refractive index of 1.55 or less at a wavelength of 450 nm. Although not shown in table 7, the refractive index of the other compound according to the present invention was also lower than 1.55 at a wavelength of 450 nm.

Claims

1. A compound for a cover layer represented by the following chemical formula 1:

< chemical formula 1>

(Cy is a substituted or unsubstituted C3-C20 cycloalkyl group, or a substituted or unsubstituted C1-C20 heterocyclic group,

L1 and L2 are each independently a direct bond, a substituted or unsubstituted C1-C50 alkylene group, a substituted or unsubstituted C2-C50 alkenylene group, a substituted or unsubstituted C1-C50 alkyleneoxy group, an ether group, a substituted or unsubstituted C1-C50 ester group, a substituted or unsubstituted C1-C50 mercapto group, a thioether group, substituted or unsubstituted C1-C50 thioester group, substituted or unsubstituted C1-C50 carbonyl group, substituted or unsubstituted-C (X1) NR 3-; substituted or unsubstituted-NR 4C (X2) -, substituted or unsubstituted-NR-, substituted or unsubstituted C3-C50 cycloalkylene, or substituted or unsubstitutedA substituted or unsubstituted C3 to C50 arylene group, or a substituted or unsubstituted C2 to C50 heteroarylene group, or a combination thereof, more specifically, it may be a combination of three or less thereof, but excludes carbazolyl,

x1 and X2 are each independently O, S, se, te, NR or CR6R7,

2. The compound for a cover layer according to claim 1, wherein,

the chemical formula 1 is represented by the following chemical formulas 2 to 5:

< chemical formula 2>

< chemical formula 3>

< chemical formula 4>

< chemical formula 5>

(in the chemical formulas 2 to 5,

the same symbols as those of the chemical formula 1 are defined as those of the chemical formula 1).

3. The compound for a cover layer according to claim 1, wherein,

cy of the chemical formula 1 is a substituted C3-C20 cycloalkyl group or a substituted C1-C20 heterocyclic group.

4. The compound for a cover layer according to claim 3, wherein,

the substituents of Cy are each independently selected from the group consisting of hydroxyl, thiol, amino, C1-C30 alkyl, C1-C30 alkoxy, C1-C30 mercapto, silyl, halogen, C3-C30 cycloalkyl, C1-C30 heterocyclyl, and combinations thereof.

5. The compound for a cover layer according to claim 1, wherein,

the L is a direct bond, carbonyl, -CH2CO-, ester-, thioester-, ether-, or thioether-group, or a combination of three or less of these groups.

6. The compound for a cover layer according to claim 1, wherein,

In the chemical formula 1, L1 is a direct bond, R1 is hydrogen, and R2 is a substituted or unsubstituted C3 to C50 cycloalkyl group, or a substituted or unsubstituted C1 to C50 heterocyclic group.

7. The compound for a cover layer according to claim 1, wherein,

the Cy is selected from the following chemical formulas A-1 to A-21:

(in the chemical structural formulae A-1 to A-21, each W is independently a methyl group, an ethyl group, a tert-butyl group, a cyclohexyl group, an adamantyl group, a dihydro-amino group, a dimethylamino group, a hydroxy group, a methoxy group, a thiol group, a methylthio group, a fluoro group, a trifluoromethyl group or a trimethylsilyl group,

n is each independently an integer from 0 to 10,

* Representing the binding site).

8. The compound for a cover layer according to claim 1, wherein,

the L2 is a direct bond and R2 is hydrogen.

9. The compound for a cover layer according to claim 1, wherein,

in the chemical formula 1, one or more of-L1-R1 and-L2-R2 may each independently be selected from the following chemical formulas B-1 to B-47:

(in the chemical structural formula, each W1 is independently methyl, ethyl, tertiary butyl, cyclohexyl, adamantyl, dihydro-amino, dimethylamino, hydroxy, methoxy, thiol, methylthio, nitrile, nitro, fluoro, trifluoromethyl or trimethylsilyl,

n is each independently an integer from 0 to 10,

* Representing the binding site).

10. The compound for a cover layer according to claim 9, wherein,

more than one of the chemical formulas B-1 to B-47 may each independently adopt a chemical formula in which the-CO structure in the chemical formulas B-1 to B-47 is substituted by-Z-, which is-O-, -S-, -CH2CO-, -CH2-NH-CO-, -O-NH-CO-, -S-NH-CO-, -CO-NH-CO-, -NH-C (=nme) -, -NHC (=chme) -, -NHCOO-, -NH-, -CO-NH-, -OCONH-, -CO-NH-, -CS-, -C (=nh) -, -C (=nme) -, -C (=chme) -, -SCO-, -OCO-, -CH2-, or "".

11. The compound for a cover layer according to claim 1, wherein,

the compound for the cover layer is one of the following compounds:

/>

12. the compound for a cover layer according to claim 1, wherein,

the refractive index of the compound for the cover layer at a wavelength of 450nm is 1.55 or less.

13. An organic light-emitting element, wherein,

a cover layer comprising a compound for a cover layer according to claim 1.

14. The organic light-emitting device according to claim 13, wherein,

the organic light emitting element includes:

A first electrode;

a second electrode; the method comprises the steps of,

more than one organic layer arranged on the inner sides of the first electrode and the second electrode;

the cover layer is disposed outside one or more of the first electrode and the second electrode.

15. The organic light-emitting device according to claim 13, wherein,

the thickness of the covering layer is thatTo->Is within the scope of (2).

16. The organic light-emitting device according to claim 13, wherein,

the refractive index of the cover layer at a wavelength of 450nm is 1.55 or less.

17. The organic light-emitting device according to claim 14, wherein,

the cover layer comprises a first cover layer comprising the compound for cover layer according to claim 1 and a second cover layer having a refractive index greater than that of the first cover layer.

18. The organic light-emitting device according to claim 17, wherein,

the second cover layer is interposed between the first cover layer and the first electrode or between the first cover layer and the second electrode.

19. The organic light-emitting device according to claim 17, wherein,

the second cover layer is in contact with the first cover layer and the first electrode or in contact with the first cover layer and the second electrode.

20. The organic light-emitting device according to claim 17, wherein,

the total thickness of the first cover layer and the second cover layer is 100 toIs within the scope of (2).

21. The organic light-emitting device according to claim 17, wherein,

the refractive index of the first cover layer at a wavelength of 450nm is 1.55 or less, the refractive index of the second cover layer at a wavelength of 450nm is 2.10 or more, and the difference between the refractive index of the first cover layer and the refractive index of the second cover layer at a wavelength of 450nm is in the range of 0.2 to 1.2.