CN117062456A

CN117062456A - Light-emitting element

Info

Publication number: CN117062456A
Application number: CN202310460037.1A
Authority: CN
Inventors: 吴一洙; 高效敏; 李宝罗
Original assignee: Samsung Display Co Ltd
Current assignee: Samsung Display Co Ltd
Priority date: 2022-05-13
Filing date: 2023-04-25
Publication date: 2023-11-14

Abstract

There is provided a light emitting element including: a first electrode; a hole transport region disposed on the first electrode; an emission layer disposed on the hole transport region; an electron transport region disposed on the emission layer; and a second electrode disposed on the electron transport region, wherein the hole transport region comprises a first hole transport layer and a second hole transport layer, the first hole transport layer being disposedA second hole transport layer disposed between the first hole transport layer and the emission layer and having a refractive index greater than that of the first hole transport layer, and having a refractive index of about 6.0x10, being adjacent to the first electrode and including a first amine compound represented by formula 1 below ^‑5 cm/(V.sec) to about 10.0x10 ^‑4 cm/(v·sec). [ 1 ]]Wherein the variables in formula 1 are the same as defined in the specification.

Description

Light-emitting element

The present patent application claims priority from korean patent application No. 10-2022-0058793, filed on day 13 of 5 in 2022, and korean patent application No. 10-2023-0005959, filed on day 16 in 2023, 1, the entire contents of which are incorporated herein by reference.

Technical Field

The present disclosure relates herein to a light emitting element and a display device including the same, and more particularly, to a light emitting element including a plurality of hole transport layers and a display device including the same.

Background

Recently, development of an organic electroluminescent display device as an image display device is actively underway. The organic electroluminescent display device includes a so-called self-luminous light emitting element in which holes and electrons injected from the first electrode and the second electrode are recombined in an emission layer, and thus a light emitting material of the emission layer emits light to realize display.

When the light-emitting element is applied to a display device, a light-emitting element having a low driving voltage, high light-emitting efficiency, and long service life is required, and development of a material for a light-emitting element capable of stably obtaining such characteristics is continuously required.

In addition, in order to realize a light-emitting element having high light-emitting efficiency, studies on optimization of the structure in the light-emitting element are being conducted.

Disclosure of Invention

The present disclosure provides a light emitting element exhibiting excellent light emitting efficiency and a display device including the same.

Embodiments of the inventive concept provide a light emitting element including: a first electrode; a hole transport region disposed on the first electrode; an emission layer disposed on the hole transport region; an electron transport region disposed on the emission layer; and a second An electrode disposed on the electron transport region, wherein the hole transport region includes a first hole transport layer disposed adjacent to the first electrode and including a first amine compound represented by formula 1 below, and a second hole transport layer disposed between the first hole transport layer and the emission layer and having a refractive index greater than that of the first hole transport layer, and the first hole transport layer has a refractive index of about 6.0x10 ^-5 cm/(V.sec) to about 10.0x10 ^-4 conductivity in cm/(v·sec):

[ 1]

Wherein, in the above formula 1,

R ₁ ar is a substituted or unsubstituted cycloalkyl group having 6 to 12 ring-forming carbon atoms ₁ And Ar is a group ₂ Each independently is a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms, L is a direct bond, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms, and FR is represented by the following formula 2-1 or formula 2-2:

[ 2-1]

[ 2-2]

In the above formulas 2-1 and 2-2,

X ₁ is CR (CR) _c R _d 、NR _e O or S, X ₂ Is CR (CR) _f Or N, R _a 、R _b1 、R _b2 R is as follows _c To R _f Each independently is a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, and is optionally bonded to an adjacent group to form a ring, m is an integer of 0 to 4, n1 is an integer of 0 to 3, n2 is an integer of 0 to 4, and in the above formulae 2-1 and 2-2, "-" means a position of L in the above formula 1.

In an embodiment, the first hole transport layer may have a refractive index of about 1.4 to about 1.75.

In an embodiment, the second hole transport layer may have a refractive index of about 1.8 to about 2.0.

In an embodiment, the light emitting element may further include a third hole transport layer disposed between the second hole transport layer and the emission layer, and including a second amine compound represented by formula 1 above.

In an embodiment, the third hole transport layer may have a refractive index of about 1.4 to about 1.75.

In an embodiment, the hole transport region may further include a fourth hole transport layer disposed between the first hole transport layer and the second hole transport layer or between the second hole transport layer and the third hole transport layer or between both the first hole transport layer and the second hole transport layer, and including a third amine compound represented by formula 1 above.

In an embodiment, the refractive index of the fourth hole transport layer may be greater than the refractive index of the first hole transport layer and less than the refractive index of the second hole transport layer.

In an embodiment, at least one of the first to fourth hole transport layers may further include a compound represented by the following formula H-1:

[ H-1]

Wherein, in the above formula H-1,

Ar _a and Ar is a group _b Each independently is a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, ar _c Is a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, L ₁ And L ₂ Each independently is a direct bond, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms, and p and q are each independently integers of 0 to 10.

In an embodiment, the light emitting element may further include a fourth hole transport layer disposed between the first hole transport layer and the second hole transport layer or between the second hole transport layer and the emission layer, or both the first hole transport layer and the second hole transport layer and the emission layer, and including a third amine compound represented by formula 1 above.

In an embodiment, the first hole transport layer may be doped with about 1% to about 3% of a p-dopant, and the p-dopant may include at least one of a halogenated metal compound, a quinone derivative, a metal oxide such as tungsten oxide, and a cyano-containing compound.

In an embodiment, the first amine compound represented by the above formula 1 may be represented by any one of the following formulas 1-1 to 1-5:

[ 1-1]

[ 1-2]

[ 1-3]

[ 1-4]

[ 1-5]

Wherein, in the above formulae 1-1 to 1-5, R ₁ 、L、Ar ₁ And Ar is a group ₂ As defined in formula 1 above, and X ₁ 、X ₂ 、R _a 、R _b1 、R _b2 M, n1 and n2 are the same as defined in the above formulae 2-1 and 2-2.

In an embodiment, the first amine compound represented by the above formula 1 may be represented by the following formula 3:

[ 3]

In the above formula 3, the number of the organic molecules,

R ₁₁ and R is ₁₂ Each independently is a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, and is optionally bonded to an adjacent group to form a ring, s1 and s2 are each independently an integer of 0 to 4, and R ₁ L and FR are the same as defined in formula 1 above.

In embodiments, R ₁ May be a substituted or unsubstituted cyclohexyl group, a substituted or unsubstituted bicycloheptyl group, a substituted or unsubstituted bicyclooctyl group, a substituted or unsubstituted bicyclononyl group, or a substituted or unsubstituted adamantyl group.

In embodiments, R _c And R is _d May each independently be a substituted or unsubstituted methyl group, a substituted or unsubstituted heptyl group, a substituted or unsubstituted cyclohexyl group, a substituted or unsubstituted phenyl group, or may be combined with each other to form a cyclopentane or fluorene ring.

In embodiments, R _f May be a substituted or unsubstituted aryl group having from 6 to 30 ring-forming carbon atoms.

In an embodiment of the inventive concept, a light emitting element includes: a first electrode; a hole transport region disposed on the first electrode; an emission layer disposed on the hole transport region; an electron transport region disposed on the emission layer; and a second electrode disposed on the electron transport region, wherein the hole transport region includes a first hole transport layer disposed adjacent to the first electrode, including a first amine compound represented by formula 1 below, and having a refractive index of about 1.4 to about 1.75, and the first hole transport layer has a refractive index of about 6.0x10 ^-5 cm/(V.sec) to about 10.0x10 ^-4 conductivity in cm/(v·sec):

[ 1]

In the above formula 1, the number of the organic molecules,

R ₁ ar is a substituted or unsubstituted cycloalkyl group having 6 to 12 ring-forming carbon atoms ₁ And Ar is a group ₂ Each independently is a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms, L is a direct bond, a substituted or unsubstituted aryl group havingArylene of 6 to 30 ring-forming carbon atoms or substituted or unsubstituted heteroarylene of 2 to 30 ring-forming carbon atoms, and FR is represented by the following formula 2-1 or formula 2-2:

[ 2-1]

[ 2-2]

In the above formulas 2-1 and 2-2,

In an embodiment of the inventive concept, a display device includes a plurality of light emitting elements, wherein each of the light emitting elements includes: a first electrode; a hole transport region disposed on the first electrode; an emission layer disposed on the hole transport region; an electron transport region disposed on the emission layer; and a second electrode disposed on the electron transport region, and the hole transport region includes a first hole transport layer disposed adjacent to the first electrode and including a first amine compound represented by formula 1 below, and a second hole transport layer disposed between the first hole transport layer and the light-emitting layerBetween the emissive layers and having a refractive index greater than that of the first hole transport layer, and the first hole transport layer has a refractive index of about 6.0x10 ^-5 cm/(V.sec) to about 10.0x10 ^-4 conductivity in cm/(v·sec):

[ 1]

In formula 1 above, R ₁ Ar is a substituted or unsubstituted cycloalkyl group having 6 to 12 ring-forming carbon atoms ₁ And Ar is a group ₂ Each independently is a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms, L is a direct bond, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms, and FR is represented by the following formula 2-1 or formula 2-2:

[ 2-1]

[ 2-2]

In the above formulas 2-1 and 2-2,

X ₁ is CR (CR) _c R _d 、NR _e O or S, X ₂ Is CR (CR) _f Or N, R _a 、R _b1 、R _b2 R is as follows _c To R _f Are each independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, andand optionally bonded to adjacent groups to form a ring, m is an integer of 0 to 4, n1 is an integer of 0 to 3, n2 is an integer of 0 to 4, and in the above formulae 2-1 and 2-2, "-" means a position of L in the above formula 1.

Drawings

The accompanying drawings are included to provide a further understanding of the inventive concepts, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the inventive concept and, together with the description, serve to explain the principles of the inventive concept. In the drawings:

fig. 1 is a plan view illustrating a display device according to an embodiment of the inventive concept;

fig. 2 is a cross-sectional view of a display device according to an embodiment of the inventive concept;

Fig. 3 is a cross-sectional view schematically showing a light emitting element according to an embodiment of the inventive concept;

fig. 4 is a cross-sectional view schematically showing a light emitting element according to an embodiment of the inventive concept;

fig. 5 is a cross-sectional view schematically showing a light emitting element according to an embodiment of the inventive concept;

fig. 6 is a cross-sectional view schematically showing a light emitting element according to an embodiment of the inventive concept;

fig. 7 is a cross-sectional view schematically showing a light emitting element according to an embodiment of the inventive concept;

fig. 8 is a cross-sectional view schematically showing a light emitting element according to an embodiment of the inventive concept;

fig. 9 is a cross-sectional view schematically showing a light emitting element according to an embodiment of the inventive concept;

fig. 10 is a cross-sectional view of a display device according to an embodiment of the inventive concept;

fig. 11 is a cross-sectional view of a display element layer according to an embodiment of the inventive concept;

fig. 12 is a cross-sectional view of a display device according to an embodiment of the inventive concept;

fig. 13A, 13B, and 13C are graphs showing luminous efficiency versus color coordinates; and

fig. 14 is a bar chart showing the luminances of R, G and B of each light emitting element of the comparative example and example.

Detailed Description

The inventive concept may be modified in numerous alternative forms, and thus specific embodiments will be illustrated in the drawings and described in detail. It should be understood, however, that there is no intention to limit the inventive concepts to the specific forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the inventive concept.

When explaining each of the drawings, the same reference numerals are used for the same elements. In the drawings, the size of each structure is shown exaggerated for clarity of the present disclosure. It will be understood that, although the terms "first," "second," etc. may be used herein to describe various components, these components should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments of the inventive concepts. Terms in the singular may include the plural unless the context clearly indicates otherwise.

In this specification, it will be understood that the terms "comprises" or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components, or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or groups thereof.

In this specification, when a layer, film, region, or sheet is referred to as being "on" or "in" another layer, film, region, or sheet, it can be directly on the other layer, film, region, or sheet, but intervening layers, films, regions, or sheets may also be present. Conversely, when a component (such as a layer, film, region, or plate) is referred to as being "under" or "on" the lower portion of "another component," it can be "directly under" the other portion, but intervening components may also be present. In addition, in the specification, it will be understood that when an element is referred to as being disposed "on" another element, it can be disposed on an upper portion of the other element or can be disposed on a lower portion of the other element.

In the specification, the term "substituted or unsubstituted" may mean substituted with at least one substituent selected from the group consisting of deuterium atom, halogen atom, cyano group, nitro group, amino group, silyl group, oxy group, thio group, sulfinyl group, sulfonyl group, carbonyl group, boron group, phosphine oxide group, phosphine sulfide group, alkyl group, alkenyl group, alkynyl group, hydrocarbon ring group, aryl group and heterocyclic group, or unsubstituted. In addition, each of the substituents exemplified above may be substituted or unsubstituted. For example, biphenyl may be interpreted as aryl or phenyl substituted with phenyl.

In the specification, the phrase "bonded to an adjacent group to form a ring" may mean that a group (or portion) is bonded to an adjacent group to form a substituted or unsubstituted hydrocarbon ring or a substituted or unsubstituted heterocyclic ring. The hydrocarbon ring includes aliphatic hydrocarbon rings and aromatic hydrocarbon rings. The heterocyclic ring includes aliphatic heterocyclic ring and aromatic heterocyclic ring. The hydrocarbon ring and the heterocyclic ring may be monocyclic or polycyclic. In addition, a ring formed by bonding to each other may be connected to another ring to form a screw structure.

In the specification, the term "adjacent group" may mean a substituent substituted for an atom directly connected to an atom substituted with a corresponding substituent, another substituent substituted for an atom substituted with a corresponding substituent, or a substituent spatially positioned at the closest position to the corresponding substituent. For example, two methyl groups in 1, 2-dimethylbenzene may be interpreted as "adjacent groups" to each other, and two ethyl groups in 1, 1-diethylcyclopentane may be interpreted as "adjacent groups" to each other. In addition, two methyl groups in 4, 5-dimethylfii can be interpreted as "adjacent groups" to each other.

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

In the specification, the alkyl group may be a straight chain type, a branched chain type or a cyclic type. The number of carbons in the alkyl group is 1 to 50, 1 to 30, 1 to 20, 1 to 10, or 1 to 6. Examples of alkyl groups may include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, isobutyl, 2-ethylbutyl, 3-dimethylbutyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, cyclopentyl, 1-methylpentyl, 3-methylpentyl, 2-ethylpentyl, 4-methyl-2-pentyl, n-hexyl, 1-methylhexyl, 2-ethylhexyl, 2-butylhexyl, cyclohexyl, 4-methylcyclohexyl, 4-tert-butylcyclohexyl, n-heptyl, 1-methylheptyl, 2-dimethylheptyl, 2-ethylheptyl, 2-butylheptyl, n-octyl, tert-octyl, 2-ethyloctyl, 2-hexyloctyl, 3, 7-dimethyloctyl cyclooctyl, n-nonyl, n-decyl, adamantyl, 2-ethyldecyl, 2-butyldecyl, 2-hexyldecyl, 2-octyldecyl, n-undecyl, n-dodecyl, 2-ethyldodecyl, 2-butyldodecyl, 2-hexyldodecyl, 2-octyldodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, 2-ethylhexadecyl, 2-butylhexadecyl, 2-hexylhexadecyl, 2-octylhexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, n-eicosyl, 2-ethyleicosyl, 2-hexyleicosyl, 2-octyleicosyl, n-eicosyl, N-docosanyl, n-tricosyl, n-tetracosyl, n-pentacosyl, n-hexacosyl, n-heptacosyl, n-octacosyl, n-nonacosyl, n-triacontyl, etc., but embodiments of the inventive concept are not limited thereto.

In the specification, hydrocarbon ring group means any functional group or substituent derived from an aliphatic hydrocarbon ring. The hydrocarbon ring group may be a saturated hydrocarbon ring group having 5 to 20 ring-forming carbon atoms.

In the specification, aryl means any functional group or substituent derived from an aromatic hydrocarbon ring. The aryl group may be a monocyclic aryl group or a polycyclic aryl group. The number of ring-forming carbon atoms in the aryl group may be 6 to 30, 6 to 20, or 6 to 15. Examples of aryl groups may include phenyl, naphthyl, fluorenyl,Anthracenyl, phenanthryl, biphenyl, terphenyl, tetrabiphenyl, pentabiphenyl, hexabiphenyl, benzo [9,10 ]]Phenanthryl, pyrenyl, benzofluoranthenyl,Basic, etc., but embodiments of the inventive concept are not so limited.

In the specification, a fluorenyl group may be substituted, and two substituents may be combined with each other to form a spiro structure. Examples of substituted fluorenyl groups are as follows. However, embodiments of the inventive concept are not limited thereto.

By heterocyclyl herein is meant any functional group or substituent derived from a ring comprising at least one of B, O, N, P, si, S and Se as a heteroatom. Heterocyclic groups include aliphatic heterocyclic groups and aromatic heterocyclic groups. The aromatic heterocyclic group may be a heteroaryl group. The aliphatic and aromatic heterocycles may be monocyclic or polycyclic.

In the specification, the heterocyclic group may contain at least one of B, O, N, P, si, se and S as a heteroatom. If the heterocyclyl contains two or more heteroatoms, the two or more heteroatoms may be the same or different. The heterocyclic group may be a monocyclic heterocyclic group or a polycyclic heterocyclic group, and has a concept including heteroaryl groups. The number of ring-forming carbon atoms in the heterocyclyl group may be 2 to 30, 2 to 20, or 2 to 10.

In the specification, the aliphatic heterocyclic group may include at least one of B, O, N, P, si, se and S as a heteroatom. The number of ring-forming carbon atoms in the aliphatic heterocyclic group may be 2 to 30, 2 to 20, or 2 to 10. Examples of the aliphatic heterocyclic group may include an ethylene oxide group, a sulfoethylene group, a pyrrolidinyl group, a piperidinyl group, a tetrahydrofuranyl group, a tetrahydrothienyl group, a thialkyl group, a tetrahydropyranyl group, a 1, 4-dioxanyl group, and the like, but embodiments of the inventive concept are not limited thereto.

In the specification, the heteroaryl group may include at least one of B, O, N, P, si, se and S as a heteroatom. When the heteroaryl group comprises two or more heteroatoms, the two or more heteroatoms may be the same as or different from each other. Heteroaryl groups may be monocyclic heteroaryl groups or polycyclic heteroaryl groups. The number of ring-forming carbon atoms in the heteroaryl group may be 2 to 30, 2 to 20, or 2 to 10. Examples of heteroaryl groups may include thienyl, furyl, pyrrolyl, imidazolyl, triazolyl, pyridyl, bipyridyl, pyrimidinyl, triazinyl, acridinyl, pyridazinyl, pyrazinyl, quinolinyl, quinazolinyl, quinoxalinyl, phenoxazinyl, phthalazinyl, pyridopyrimidinyl, pyridopyrazinyl, pyrazinopyrazinyl, isoquinolinyl, indolyl, carbazolyl, N-arylcarbazolyl, N-heteroarylcarbazolyl, N-alkylcarbazolyl, benzoxazolyl, benzimidazolyl, benzothiazolyl, benzocarbazolyl, benzothienyl, dibenzothienyl, thienothioyl, benzofuranyl, phenanthroline, thiazolyl, isoxazolyl, oxazolyl, oxadiazolyl, thiadiazolyl, phenothiazinyl, dibenzosilol, dibenzofuranyl, and the like, but embodiments of the inventive concept are not limited thereto.

In the specification, the above description of aryl groups may be applied to arylene groups, except that arylene groups are divalent groups. In addition to heteroarylene being a divalent group, the above description of heteroaryl may be applicable to heteroarylene.

In the specification, silyl groups include alkylsilyl groups and arylsilyl groups. Examples of the silyl group may include a trimethylsilyl group, a triethylsilyl group, a t-butyldimethylsilyl group, a vinyldimethylsilyl group, a propyldimethylsilyl group, a triphenylsilyl group, a diphenylsilyl group, a phenylsilyl group, and the like, but embodiments of the inventive concept are not limited thereto.

In the specification, a thio group may include an alkylthio group and an arylthio group. Thio may mean that the sulfur atom is bound to an alkyl or aryl group as defined above. Examples of the thio group may include a methylthio group, an ethylthio group, a propylthio group, a pentylthio group, a hexylthio group, an octylthio group, a dodecylthio group, a cyclopentylthio group, a cyclohexylthio group, a phenylthio group, a naphthylthio group, and the like, but embodiments of the inventive concept are not limited thereto.

In the specification, an oxygen group may mean that an oxygen atom is bonded to an alkyl group or an aryl group as defined above. The oxy group may include an alkoxy group and an aryloxy group. Alkoxy groups may be straight, branched or cyclic. The number of carbon atoms in the alkoxy group is not particularly limited, but may be, for example, 1 to 20 or 1 to 10. Examples of the oxy group may include methoxy, ethoxy, n-propoxy, isopropoxy, butoxy, pentyloxy, hexyloxy, octyloxy, nonyloxy, decyloxy, benzyloxy, and the like, but embodiments of the inventive concept are not limited thereto.

In the specification, an alkenyl group may be a straight chain or a branched chain. The number of carbon atoms in the alkenyl group is not particularly limited, but 2 to 30, 2 to 20, or 2 to 10. Examples of the alkenyl group include vinyl, 1-butenyl, 1-pentenyl, 1, 3-butadienyl, styryl, etc., but embodiments of the inventive concept are not limited thereto.

In the specification, the number of carbon atoms in the amine group is not particularly limited, but may be 1 to 30. Amine groups may include alkyl amine groups and aryl amine groups. Examples of the amine group may include a methylamino group, a dimethylamino group, an anilino group, a diphenylamino group, a naphthylamino group, a 9-methyl-anthrylamino group, and the like, but embodiments of the inventive concept are not limited thereto.

In the specification, the alkyl group among the alkoxy group, the alkylthio group, the alkylsulfinyl group, the alkylsulfonyl group, the alkylaryl group, the alkylamino group, the alkylboryl group, the alkylsilyl group, and the alkylamino group is the same as the examples of the alkyl group described above.

In the specification, the aryl group among the aryloxy group, the arylthio group, the arylsulfinyl group, the arylsulfonyl group, the arylamino group, the arylboron group, the arylsilyl group, and the arylamino group is the same as the above-described examples of the aryl group.

In the specification, a direct bond may mean a single bond.

On the other hand, in the specification,and "-" means the location to be connected.

Hereinafter, embodiments of the inventive concept will be described with reference to the accompanying drawings.

Fig. 1 is a plan view showing an embodiment of the display device DD. Fig. 2 is a cross-sectional view of the display device DD of the embodiment. Fig. 2 is a sectional view showing a portion taken along line I-I' of fig. 1.

The display device DD may include a display panel DP and an optical layer PP disposed on the display panel DP on the third direction axis DR 3. The display panel DP comprises light emitting elements ED-1, ED-2 and ED-3. The display device DD may comprise a plurality of light emitting elements ED-1, ED-2 and ED-3.

The optical layer PP may be disposed on the display panel DP to control light reflected in the display panel DP due to external light. The optical layer PP may comprise, for example, a polarizing layer or a color filter layer. On the other hand, in the display device DD of the embodiment, the optical layer PP may be omitted unlike the configuration shown in the drawings.

The base substrate BL may be disposed on the optical layer PP. The base substrate BL may be a member providing a base surface on which the optical layer PP is disposed. The base substrate BL may be a glass substrate, a metal substrate, a plastic substrate, or the like. However, embodiments of the inventive concept are not limited thereto, and the base substrate BL may be an inorganic layer, an organic layer, or a composite material layer. In addition, unlike the illustrated configuration, in the embodiment, the base substrate BL may be omitted.

The display device DD according to an embodiment may further comprise a filler layer (not shown). A filler layer (not shown) may be disposed between the display element layer DP-ED and the base substrate BL. The filler layer (not shown) may be a layer of organic material. The filling layer (not shown) may include at least one of an acrylic resin, a silicone resin, and an epoxy resin.

The display panel DP may include a base layer BS, a circuit layer DP-CL disposed on the base layer BS, and a display element layer DP-ED. The display element layer DP-ED may include a pixel defining film PDL, light emitting elements ED-1, ED-2, and ED-3 disposed between portions of the pixel defining film PDL, and an encapsulation layer TFE disposed over the light emitting elements ED-1, ED-2, and ED-3.

The base layer BS may be a member that provides a base surface on which the display element layers DP-ED are disposed. The base layer BS may be a glass substrate, a metal substrate, a plastic substrate, or the like. However, the embodiment is not limited thereto, and the base layer BS may be an inorganic layer, an organic layer, or a composite material layer.

In an embodiment, the circuit layer DP-CL is disposed on the base layer BS, and the circuit layer DP-CL may include a plurality of transistors (not shown). Each of the transistors (not shown) may include a control electrode, an input electrode, and an output electrode. For example, the circuit layer DP-CL may include switching transistors and driving transistors for driving the light emitting elements ED-1, ED-2, and ED-3 of the display element layer DP-ED.

Each of the light emitting elements ED-1, ED-2, and ED-3 may have a structure of the light emitting element ED according to the embodiment of fig. 3 to 9, which will be described later. Each of the light emitting elements ED-1, ED-2, and ED-3 may include a first electrode EL1, a hole transport region HTR, emission layers EML-R, EML-G and EML-B, an electron transport region ETR, and a second electrode EL2.

Fig. 2 shows an embodiment in which emission layers EML-R, EML-G and EML-B of light emitting elements ED-1, ED-2, and ED-3 are disposed in an opening OH defined in a pixel defining film PDL, and a hole transporting region HTR, an electron transporting region ETR, and a second electrode EL2 are disposed as a common layer in the entire light emitting elements ED-1, ED-2, and ED-3. However, embodiments of the inventive concept are not limited thereto, and unlike the configuration shown in fig. 2, the hole transport region HTR and the electron transport region ETR in the embodiments may be disposed by being patterned inside the opening OH defined in the pixel defining film PDL. For example, in an embodiment, the hole transport regions HTR, the emission layers EML-R, EML-G and EML-B, and the electron transport regions ETR of the light emitting elements ED-1, ED-2, and ED-3 may be provided by patterning in an inkjet printing method.

The encapsulation layer TFE may cover the light emitting elements ED-1, ED-2 and ED-3. The encapsulation layer TFE may encapsulate the light emitting elements ED-1, ED-2, and ED-3. The encapsulation layer TFE may be a thin film encapsulation layer. Encapsulation layer TFE may be formed by laminating one or more layers. The encapsulation layer TFE includes at least one insulating layer. The encapsulation layer TFE according to an embodiment may include at least one inorganic film (hereinafter, encapsulation inorganic film). The encapsulation layer TFE according to embodiments may further include at least one organic film (hereinafter, an encapsulation organic film) and at least one encapsulation inorganic film.

The encapsulation inorganic film protects the display element layer DP-ED from moisture/oxygen, and the encapsulation organic film protects the display element layer DP-ED from foreign substances such as dust particles. The encapsulation inorganic film may include silicon nitride, silicon oxynitride, silicon oxide, titanium oxide, aluminum oxide, or the like, but embodiments of the inventive concept are not particularly limited thereto. The encapsulating organic film may include an acrylic compound, an epoxy compound, and the like. The encapsulation organic film may include a photopolymerizable organic material, but embodiments of the inventive concept are not particularly limited thereto.

The encapsulation layer TFE may be disposed on the second electrode EL2, and may be disposed to fill the opening OH.

Referring to fig. 1 and 2, the display device DD may include a non-light emitting region NPXA and light emitting regions PXA-R, PXA-G and PXA-B. The light emitting regions PXA-R, PXA-G and PXA-B may be regions in which light generated by the respective light emitting elements ED-1, ED-2 and ED-3 is emitted. The light emitting areas PXA-R, PXA-G and PXA-B may be spaced apart from each other in a plane.

Each of the light emitting areas PXA-R, PXA-G and PXA-B may be an area divided by the pixel defining film PDL. The non-light emitting region NPXA may be a region between adjacent light emitting regions PXA-R, PXA-G and PXA-B corresponding to the pixel defining film PDL. On the other hand, in the specification, the light emitting areas PXA-R, PXA-G and PXA-B may correspond to pixels, respectively. The pixel defining film PDL may divide the light emitting elements ED-1, ED-2, and ED-3. The emission layers EML-R, EML-G and EML-B of the light emitting elements ED-1, ED-2 and ED-3 may be disposed in the opening OH defined in the pixel defining film PDL and separated from each other.

The light emitting areas PXA-R, PXA-G and PXA-B may be divided into a plurality of groups according to the color of light generated from the light emitting elements ED-1, ED-2 and ED-3. In the display device DD of the embodiment shown in fig. 1 and 2, three light emitting areas PXA-R, PXA-G and PXA-B emitting red, green and blue light, respectively, are exemplarily shown. For example, the display device DD of the embodiment may include red, green, and blue light emitting regions PXA-R, PXA-G, and PXA-B that are separated from each other.

In the display device DD according to the embodiment, the plurality of light emitting elements ED-1, ED-2, and ED-3 may emit light beams having different wavelengths from each other. For example, in an embodiment, the display device DD may include a first light emitting element ED-1 that emits red light, a second light emitting element ED-2 that emits green light, and a third light emitting element ED-3 that emits blue light. That is, the red, green and blue light emitting regions PXA-R, PXA-G and PXA-B of the display device DD may correspond to the first, second and third light emitting elements ED-1, ED-2 and ED-3, respectively.

However, embodiments of the inventive concept are not limited thereto, and the first to third light emitting elements ED-1, ED-2, and ED-3 may emit light beams in the same wavelength range, or at least one light emitting element may emit light beams in a wavelength range different from other light emitting elements. For example, the first to third light emitting elements ED-1, ED-2 and ED-3 may all emit blue light.

The light emitting areas PXA-R, PXA-G and PXA-B in the display device DD according to the embodiment may be arranged in a stripe form. Referring to fig. 1, a plurality of red light emitting areas PXA-R, a plurality of green light emitting areas PXA-G, and a plurality of blue light emitting areas PXA-B may all be arranged along the second direction DR 2. In addition, the red light emitting regions PXA-R, the green light emitting regions PXA-G, and the blue light emitting regions PXA-B may be alternately arranged in this order along the first direction DR 1.

Fig. 1 and 2 illustrate that all the light emitting areas PXA-R, PXA-G and PXA-B have similar areas, but embodiments of the inventive concept are not limited thereto. Accordingly, the light emitting regions PXA-R, PXA-G and PXA-B may have areas different from each other according to the wavelength range of the emitted light. In this case, the areas of the light emitting areas PXA-R, PXA-G and PXA-B may mean areas when viewed in a plane defined by the first and second directions DR1 and DR 2.

On the other hand, the arrangement of the light emitting areas PXA-R, PXA-G and PXA-BThe formula is not limited to the features shown in fig. 1, and the order in which the red light emitting regions PXA-R, the green light emitting regions PXA-G, and the blue light emitting regions PXA-B are arranged may be set in various combinations according to the characteristics of the display quality required in the display device DD. For example, the arrangement of the light emitting areas PXA-R, PXA-G and PXA-B may be pentileLayout or Diamond (Diamond Pixel) ^TM ) Arrangement form.

In addition, the areas of the light emitting areas PXA-R, PXA-G and PXA-B may be different from each other. For example, in an embodiment, the areas of the green light emitting areas PXA-G may be smaller than the areas of the blue light emitting areas PXA-B, but embodiments of the inventive concept are not limited thereto.

Hereinafter, fig. 3 to 9 are cross-sectional views schematically showing a light emitting element according to an embodiment. The light emitting elements ED according to the embodiment may each include a first electrode EL1, a second electrode EL2 facing the first electrode EL1, and at least one functional layer disposed between the first electrode EL1 and the second electrode EL2. The at least one functional layer may include a hole transport region HTR, an emission layer EML, and an electron transport region ETR, which are sequentially stacked. That is, each of the light emitting elements ED of the embodiment may include the first electrode EL1, the hole transporting region HTR, the emission layer EML, the electron transporting region ETR, and the second electrode EL2, which are sequentially stacked.

In comparison with fig. 3, fig. 4 shows a cross-sectional view of the light emitting element ED of the embodiment, in which the hole transport region HTR includes a hole injection layer HIL, a first hole transport layer HTL1, and a second hole transport layer HTL2, and the electron transport region ETR includes an electron injection layer EIL and an electron transport layer ETL. In addition, as compared with fig. 3, fig. 5 shows a cross-sectional view of the light emitting element ED of the embodiment, in which the hole transport region HTR includes a hole injection layer HIL, a first hole transport layer HTL1, a second hole transport layer HTL2, and an electron blocking layer EBL, and the electron transport region ETR includes an electron injection layer EIL, an electron transport layer ETL, and a hole blocking layer HBL. In comparison with fig. 3, fig. 6 shows a cross-sectional view of the light emitting element ED of the embodiment, in which the hole transport region HTR includes a hole injection layer HIL, a first hole transport layer HTL1, a second hole transport layer HTL2, and a third hole transport layer HTL3, and the electron transport region ETR includes an electron injection layer EIL and an electron transport layer ETL.

In comparison with fig. 3, fig. 7 shows a cross-sectional view of the light emitting element ED of the embodiment, in which the hole transport region HTR includes a hole injection layer HIL, a first hole transport layer HTL1, a second hole transport layer HTL2, a third hole transport layer HTL3, a 4-1 th hole transport layer HTL4-1 and a 4-2 th hole transport layer HTL4-2, and the electron transport region ETR includes an electron injection layer EIL and an electron transport layer ETL.

In comparison with fig. 3, fig. 8 shows a cross-sectional view of the light emitting element ED of the embodiment, in which the hole transport region HTR includes a hole injection layer HIL, a first hole transport layer HTL1, a second hole transport layer HTL2, a third hole transport layer HTL3, and a 4-1 th hole transport layer HTL4-1, and the electron transport region ETR includes an electron injection layer EIL and an electron transport layer ETL. Unlike the configuration shown in fig. 8, the third hole transport layer HTL3 may be omitted.

Fig. 9 shows a cross-sectional view of the light-emitting element ED of the embodiment comprising the cover layer CPL provided on the second electrode EL2, compared to fig. 6.

The light emitting element ED of the embodiment may include the first to third amine compounds of the embodiment in the hole transport region HTR, which will be described later.

In the light emitting element ED according to the embodiment, the first electrode EL1 has conductivity. The first electrode EL1 may be formed of a metal material, a metal alloy, or a conductive compound. The first electrode EL1 may be an anode or a cathode. However, embodiments of the inventive concept are not limited thereto. In addition, the first electrode EL1 may be a pixel electrode. The first electrode EL1 may be a transmissive electrode, a transflective electrode, or a reflective electrode. When the first electrode EL1 is a transmissive electrode, the first electrode EL1 may include a transparent metal oxide such as Indium Tin Oxide (ITO), indium Zinc Oxide (IZO), zinc oxide (ZnO), and Indium Tin Zinc Oxide (ITZO). If the first electrode EL1 is a transflective or reflective electrode, the first electrode EL1 can include Ag, mg, cu, al, pt, pd, au, ni, nd, ir, cr, li, Ca. LiF, mo, ti, W, their compounds, their mixtures (e.g. mixtures of Ag and Mg) or materials having a multilayer structure such as LiF/Ca or LiF/Al. Alternatively, the first electrode EL1 may have a multilayer structure including a reflective film or a transflective film formed of the above-described materials, and a transparent conductive film formed of ITO, IZO, znO, ITZO or the like. For example, the first electrode EL1 may have a three-layer structure of ITO/Ag/ITO, but embodiments of the inventive concept are not limited thereto. In addition, embodiments of the inventive concept are not limited thereto, and the first electrode EL1 may include the above-described metal materials, a combination of at least two of the above-described metal materials, an oxide of the above-described metal materials, or the like. The thickness of the first electrode EL1 may be aboutTo about->For example, the thickness of the first electrode EL1 can be about +.>To about->

The hole transport region HTR is provided on the first electrode EL 1. The hole transport region HTR may include a first hole transport layer HTL1, a second hole transport layer HTL2, and a third hole transport layer HTL3.

The hole transport region HTR may be formed using various methods such as a vacuum deposition method, a spin coating method, a casting method, a langmuir-blodgett (LB) method, an inkjet printing method, a laser printing method, and a Laser Induced Thermal Imaging (LITI) method.

Fig. 4 to 9 show that the hole transport region HTR includes the hole injection layer HIL and the plurality of hole transport layers HTL1, HTL2, HTL3, and HTL4, but the hole transport region HTR may have the plurality of hole transport layers HTL1, HTL2, HTL3, and HTL4 directly disposed on the first electrode EL1 without the hole injection layer HIL. For example, any one of the plurality of hole transport layers HTL1, HTL2, HTL3, and HTL4 may be used as the hole injection layer. In addition, the hole transport region HTR in the embodiment may further include a structure in which a buffer layer (not shown) is disposed on upper portions of the plurality of hole transport layers HTL1, HTL2, HTL3, and HTL 4.

The hole transport region HTR of the inventive concept includes a first hole transport layer HTL1 disposed on the first electrode EL 1. The first hole transport layer HTL1 is disposed adjacent to the first electrode EL 1. For example, the first hole transport layer HTL1 may be in contact with the first electrode EL1, and disposed on the first electrode EL 1.

The first hole transport layer HTL1 includes a first amine compound represented by formula 1, which will be described later. The first hole transport layer HTL1 may include a first amine compound, which will be described later, to exhibit a low refractive index and excellent conductivity (electrical conductivity). The refractive index of the first hole transport layer HTL1 (hereinafter, first refractive index) is about 1.4 to about 1.75. For example, the first refractive index may be about 1.5 to about 1.75, for example, may be about 1.7. The conductivity of the first hole transport layer HTL1 is about 6.0x10 ^-5 cm/(V.s) to about 10.0x10 ^-4 cm/(V.s). For example, the first hole transport layer HTL1 may have a conductivity of about 6.0x10 ^-5 cm/(V.s) to about 9.0x10 ^-4 cm/(V·s)。

The first hole transport layer HTL1 may further include a charge generation material. The first hole transport layer HTL1 is disposed adjacent to the first electrode EL1, includes a charge generating material, and thus can function as a hole injection layer. In this case, the first hole transport layer HTL1 may be disposed in contact with the first electrode EL 1.

The charge generating material may be, for example, a p-dopant. In an embodiment, the first hole transport layer HTL1 may be doped with about 1% to about 3% of a p dopant. For example, the first hole transport layer HTL1 may be doped with about 1% to about 2% of a p dopant.

The p-dopant may include at least one of a halogenated metal compound, a quinone derivative, a metal oxide such as tungsten oxide, and a cyano-containing compound. Specifically, as described above, the p-dopant may include halogenated metal compounds (such as CuI and CuIRbI), quinone derivatives (such as Tetracyanoquinodimethane (TCNQ) or 2,3,5, 6-tetrafluoro-7, 8-tetracyanoquinodimethane (F) ₄ -TCNQ)), metal oxides (such as tungsten oxide or molybdenum oxide) and cyano-containing compounds (such as bipyrazino [2,3-f:2',3' -h) ]Quinoxaline-2, 3,6,7,10, 11-hexanitrile (HAT-CN) or 4- [ [2, 3-bis [ cyano- (4-cyano-2, 3,5, 6-tetrafluorophenyl) methylene]Cyclopropylidene group]-cyanomethyl group]-2,3,5, 6-tetrafluorobenzonitrile (NDP 9)).

In an embodiment, the p-dopant may be NDP9. In an embodiment, the first hole transport layer HTL1 may be doped with about 1% to about 3% NDP9. However, embodiments of the inventive concept are not limited thereto.

On the other hand, the first hole transport layer HTL1 may further contain a hole transport material represented by formula H-1, which will be described later.

The hole transport region HTR of the inventive concept further includes a second hole transport layer HTL2 disposed on the first hole transport layer HTL 1.

The second hole transport layer HTL2 is disposed between the first hole transport layer HTL1 and the emission layer EML.

The refractive index of the second hole transport layer HTL2 (hereinafter, second refractive index) is greater than the first refractive index.

The second refractive index is about 1.8 to about 2.0. For example, the second refractive index may be about 1.9.

The second hole transport layer HTL2 may include a hole transport material represented by formula H-1, which will be described later, and has excellent hole mobility.

The hole transport region HTR of the inventive concept further includes a third hole transport layer HTL3. The third hole transport layer HTL3 may be disposed between the second hole transport layer HTL2 and the emission layer EML. The third hole transport layer HTL3 may include a second amine compound represented by formula 1, which will be described later, to exhibit about 6.0x10 ^-5 cm/(V.s) to about 10.0x10 ^-4 cm/(v·s) conductivity. The second amine compound may be the same as the first amine compound. However, embodiments of the inventive concept are not limited thereto, and the first amine compound and the second amine compound may be different.

On the other hand, the third hole transport layer HTL3 may further include a hole transport material represented by formula H-1, which will be described later.

The refractive index of the third hole transport layer HTL3 (hereinafter, third refractive index) may be smaller than the second refractive index. The third refractive index may be about 1.4 to about 1.75. For example, the refractive index of the third hole transport layer may be about 1.7. The electron blocking layer EBL may be further disposed between the third hole transport layer HTL3 and the emission layer EML.

The light emitting element ED of the embodiment may include a first electrode EL1, a first hole transport layer HTL1 disposed on the first electrode EL1, a second hole transport layer HTL2 disposed on the first hole transport layer HTL1, a third hole transport layer HTL3 disposed on the second hole transport layer HTL2, an emission layer EML disposed on the third hole transport layer HTL3, an electron transport region ETR disposed on the emission layer EML, and a second electrode EL2.

However, embodiments of the inventive concept are not limited thereto, and the light emitting element ED of the embodiment may not include the third hole transport layer HTL3.

The hole transport region HTR of the embodiment may further include a fourth hole transport layer HTL4.

The fourth hole transport layer HTL4 may include a third amine compound represented by formula 1, which will be described later, to exhibit about 6.0x10 ^-5 cm/(V.s) to about 10.0x10 ^-4 cm/(v·s) conductivity. The third amine compound may be the same as the first amine compound. The first to third amine compounds may all be the same. However, embodiments of the inventive concept are not limited thereto, and at least one of the first to third amine compounds may be different from others.

On the other hand, the fourth hole transport layer HTL4 may further include a hole transport material represented by formula H-1, which will be described later.

The refractive index of the fourth hole transport layer HTL4 (hereinafter, fourth refractive index) may be greater than the first refractive index and less than the second refractive index.

The fourth hole transport layer HTL4 may be disposed on at least one of the upper and lower portions of the second hole transport layer HTL 2. In particular, the fourth hole transport layer HTL4 may be disposed between the first hole transport layer HTL1 and the second hole transport layer HTL2 or between the second hole transport layer HTL2 and the emission layer EML, or between both the first hole transport layer HTL1 and the second hole transport layer HTL2 and between the second hole transport layer HTL2 and the emission layer EML.

At least one fourth hole transport layer HTL4 may be provided, for example, one or two fourth hole transport layers HTL4 may be provided. The fourth hole transport layer HTL4 of the embodiment may include a 4-1 th hole transport layer HTL4-1 and a 4-2 th hole transport layer HTL4-2.

For example, the hole transport region HTR of the embodiment may include a first hole transport layer HTL1, a 4-1 th hole transport layer HTL4-1, and a second hole transport layer HTL2 sequentially stacked on the first electrode EL 1.

When the hole transport region HTR includes the third hole transport layer HTL3, the fourth hole transport layer HTL4 may be disposed between the first hole transport layer HTL1 and the second hole transport layer HTL2 or between the second hole transport layer HTL2 and the third hole transport layer HTL3, or between both the first hole transport layer HTL1 and the second hole transport layer HTL2 and between the second hole transport layer HTL2 and the third hole transport layer HTL3. For example, the hole transport region HTR of the embodiment may include a first hole transport layer HTL1, a 4-1 th hole transport layer HTL4-1, a second hole transport layer HTL2, a 4-2 th hole transport layer HTL4-2, and a third hole transport layer HTL3 sequentially stacked on the first electrode EL 1.

The light emitting element ED of the embodiment includes a plurality of hole transport layers HTL1, HTL2, HTL3, and HTL4, and thus constructive interference of light may occur to increase light extraction efficiency.

For example, referring to fig. 4, a portion of the first incident light L1 passing through the second hole transport layer HTL2 from the emission layer EML to enter toward the first hole transport layer HTL1 may be reflected toward the emission layer EML at the first interface LF 1. A portion of the second incident light L2 entering from the emission layer EML toward the second hole transport layer HTL2 may be reflected toward the emission layer EML at the second interface LF 2. In the light emitting element ED of the embodiment, constructive interference may occur between the first reflected light RL1 reflected at the first interface LF1 and the second reflected light RL2 reflected at the second interface LF 2. Therefore, the light emitting element ED of the embodiment can exhibit high external light extraction efficiency.

Referring to fig. 6, a portion of the first incident light L1 passing through the third hole transport layer HTL3 and the second hole transport layer HTL2 from the emission layer EML to enter toward the first hole transport layer HTL1 may be reflected toward the emission layer EML at the first interface LF 1. A portion of the second incident light L2 passing through the third hole transport layer HTL3 from the emission layer EML to enter toward the second hole transport layer HTL2 may be reflected toward the emission layer EML at the second interface LF 2. A portion of the third incident light L3 entering from the emission layer EML toward the third hole transport layer HTL3 may be reflected toward the emission layer EML at the third interface LF 3.

In the light emitting element ED of the embodiment, constructive interference may occur between the first reflected light RL1 reflected at the first interface LF1, the second reflected light RL2 reflected at the second interface LF2, and the third reflected light RL3 reflected at the third interface LF 3. Therefore, the light emitting element ED of the embodiment can exhibit high external light extraction efficiency.

Referring to fig. 7, the hole transport region HTR of the embodiment may include the 4-1 th reflected light RL4-1 and the 4-2 th reflected light RL4-2 in addition to the first to third reflected light RL1, RL2, and RL3 as described above in fig. 6.

Specifically, in the emission layer EML, a portion of the 4-1 th incident light L4-1 that passes through the third hole transport layer HTL3, the 4-2 th hole transport layer HTL4-2, and the second hole transport layer HTL2 to enter toward the 4-1 th hole transport layer HTL4-1 may be reflected toward the emission layer EML at the 4-1 th interface LF 4-1. The portion of the 4-2 th incident light L4-2 that passes through the third hole transport layer HTL3 from the emission layer EML to enter toward the 4-2 th hole transport layer HTL4-2 may be reflected toward the emission layer EML at the 4-2 th interface LF 4-2. In the light emitting element ED of the embodiment, constructive interference may occur between the first reflected light RL1 reflected at the first interface LF1, the 4-1 th reflected light RL4-1 reflected at the 4-1 th interface LF4-1, the second reflected light RL2 reflected at the second interface LF2, the 4-2 th reflected light RL4-2 reflected at the 4-2 th interface LF4-2, and the third reflected light RL3 reflected at the third interface LF 3. Therefore, the light emitting element ED of the embodiment can exhibit high external light extraction efficiency.

The light emitting element ED of the embodiment includes a plurality of hole transport layers HTL1, HTL2, HTL3, and HTL4 having the above-described first to fourth refractive indices, respectively, to thereby exhibit improved light emitting efficiency. The light emitting element ED of the embodiment may include the hole transport layers HTL1, HTL2, HTL3, and HTL4 having the hole transport regions HTR of different refractive indexes, thereby minimizing extinction of light emitted from the functional layers therein due to destructive interference and increasing constructive interference of light, thereby exhibiting high light extraction efficiency.

In addition, the hole transport region HTR of the embodiment includes a material having a first refractive index and having a refractive index of about 6.0x10 ^-5 cm/(V.s) to about 10.0x10 ^-4 The first hole transport layer HTL1 having conductivity of cm/(v·s) and the second hole transport layer HTL2 having a second refractive index greater than the first refractive index may thus have excellent hole mobility and improved electrical characteristics, thereby preventing leakage current from occurring when the light emitting element ED is driven. In particular, when the light emitting element ED is driven in the low gray region, occurrence of leakage current can be prevented. The hole transport region HTR of the embodiment may further include a third hole transport layer HTL3 and a fourth hole transport layer HTL4, each of the third hole transport layer HTL3 and the fourth hole transport layer HTL4 having about 6.0x10 ^-5 cm/(V.s) to about 10.0x10 ^-4 cm/(v·s), thereby exhibiting improved electrical characteristics.

The light emitting element ED of the embodiment may include a hole transport region HTR, thereby having a low driving voltage and exhibiting excellent light emitting efficiency. In addition, the light emitting element ED of the embodiment can have improved luminance in a low gray scale region, thereby improving color visibility.

In the light emitting element ED according to the embodiment, the first amine compound, the second amine compound, and the third amine compound, which are respectively included in the first hole transport layer HTL1, the third hole transport layer HTL3, and the fourth hole transport layer HTL4, may each be independently represented by the following formula 1.

Hereinafter, an amine compound represented by the following formula 1 will be described. The description of the amine compound to be described below may be equally applied to each of the first amine compound, the second amine compound, and the third amine compound.

[ 1]

In formula 1, R ₁ Is a substituted or unsubstituted cycloalkyl group having 6 to 12 ring-forming carbon atoms. For example, R ₁ May be a substituted or unsubstituted cyclohexyl group, a substituted or unsubstituted bicycloheptyl group, a substituted or unsubstituted bicyclooctyl group, a substituted or unsubstituted bicyclononyl group, or a substituted or unsubstituted adamantyl group. For example, R ₁ Can be a substituted or unsubstituted cyclohexyl, a substituted or unsubstituted bicyclo [ 2.2.1 ] or]Heptyl, substituted or unsubstituted bicyclo [ 2.2.2]Octyl, substituted or unsubstituted bicyclo [3,2 ]]Nonyl or substituted or unsubstituted adamantyl.

Ar ₁ And Ar is a group ₂ Each independently is a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms. For example, ar ₁ And Ar is a group ₂ May each independently be a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, in particular Ar ₁ And Ar is a group ₂ May each independently be a substituted or unsubstituted phenylene group.

L is a direct bond, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms. For example, L may be a direct bond or an unsubstituted phenylene group. When L is a direct bond, in formula 1 above, FR may be directly connected to the nitrogen atom.

That is, the amine compound represented by formula 1 may include a first substituent, a second substituent, and a third substituent represented by formula FR around the central nitrogen atom, the first substituent being a bicycloheptyl group, the second substituent being a substituted or unsubstituted cycloalkyl group having 6 to 12 ring-forming carbon atoms. The first to third substituents may be attached to the central nitrogen atom via a linker.

FR is represented by the following formula 2-1 or formula 2-2. In the following formulas 2-1 and 2-2, "-" means a position of L in the above formula 1.

[ 2-1]

[ 2-2]

In the formulae 2-1 to 2-2, X ₁ Is CR (CR) _c R _d 、NR _e O or S. X is X ₂ Is CR (CR) _f Or N. That is, the substituent FR represented by formula 2-1 or formula 2-2 may be a substituted or unsubstituted fluorene derivative, a substituted or unsubstituted carbazole derivative, a substituted or unsubstituted dibenzofuran derivative or a substituted or unsubstituted dibenzothiophene derivative.

R _a 、R _b1 、R _b2 R is as follows _c To R _f Each independently is a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, and is optionally bonded to an adjacent group to form a ring.

For example, R _a 、R _b1 And R is _b2 May be a hydrogen atom. For example, R _c And R is _d May each independently be a substituted or unsubstituted methyl group, a substituted or unsubstituted heptyl group, a substituted or unsubstituted cyclohexyl group, a substituted or unsubstituted phenyl group, or may be combined with each other to form a cyclopentane or fluorene ring. When R is _c And R is _d FR when combined with each other to form a cyclopentane or fluorene ringCan be formed such asIs a screw structure of (a). For example, R _f May be a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, in particular R _f May be unsubstituted phenyl.

m is an integer from 0 to 4. If m is an integer of 2 or more, a plurality of R _a May all be the same, or a plurality of R _a At least one of which may be with other R _a Different. For example, m may be 0. If m is 0, FR may not be substituted with R _a . In FR, where m is 4 and R _a The structure of all hydrogen atoms may be the same as that in which m is 0 in FR.

n1 is an integer from 0 to 3. If n1 is an integer of 2 or more, a plurality of R _b1 May all be the same, or a plurality of R _b1 At least one of which may be with other R _b1 Different. For example, n1 may be 0. If n1 is 0, FR may not be substituted with R _b1 . In FR, where n1 is 4 and R _b1 The structure of all hydrogen atoms may be the same as that in which n1 is 0 in FR.

n2 is an integer from 0 to 4. If n2 is an integer of 2 or more, a plurality of R _b2 May all be the same, or a plurality of R _b2 At least one of which may be with other R _b2 Different. For example, n2 may be 0. If n2 is 0, FR may not be substituted with R _b2 . In FR, where n2 is 4 and R _b2 The structure of all hydrogen atoms may be the same as that in which n2 is 0 in FR.

The first, third, and fourth hole transport layers HTL1, HTL3, and HTL4 as described above may include an amine compound represented by formula 1 above, thereby having a refractive index of about 1.4 to about 1.75.

In an embodiment, the amine compound represented by the above formula 1 may be represented by the following formulas 1-1 to 1-5:

[ 1-1]

[ 1-2]

[ 1-3]

[ 1-4]

[ 1-5]

Formulas 1-1 to 1-5 are cases indicating the connection positions of the substituent FR and the linking group L.

In an embodiment, the amine compound represented by formula 1 may be represented by the following formula 3:

[ 3]

Formula 3 is Ar in formula 1 ₁ And Ar is a group ₂ Is a particular case of substituted or unsubstituted phenylene groups.

In formula 3, R ₁₁ And R is ₁₂ Can all be independentIs a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, and optionally may be bonded to an adjacent group to form a ring. For example, R ₁₁ And R is ₁₂ May be a hydrogen atom.

s1 and s2 may each independently be an integer from 0 to 4. If s1 is an integer of 2 or more, a plurality of R ₁₁ May all be the same, or a plurality of R ₁₁ At least one of which may be with other R ₁₁ Different. For example, s1 may be 0. If s1 is 0, the amine compound represented by formula 1 may be unsubstituted with R ₁₁ . Wherein s1 in formula 1 is 4 and R ₁₁ The structures each of which is a hydrogen atom may be the same as those in which s1 is 0 in formula 1.

If s2 is an integer of 2 or more, a plurality of R ₁₂ May all be the same, or a plurality of R ₁₂ At least one of which may be with other R ₁₂ Different. For example, s2 may be 0. If s2 is 0, the amine compound represented by formula 1 may be unsubstituted with R ₁₂ . Wherein s2 is 4 and R in formula 1 ₁₂ The structures of all hydrogen atoms may be the same as those in which s2 is 0 in formula 1.

In formula 3 above, R ₁ L and FR are the same as defined in formula 1, formula 2-1 and formula 2-2 above.

In an embodiment, the amine compound represented by formula 3 may be represented by the following formula 3-1:

[ 3-1]

Formula 3-1 is a formula 3R ₁ And bicyclo [2, 1]]The case where the heptyl group is attached to the position of the linker. Specifically, formula 3-1 is R ₁ And bicyclo [2, 1] ]Specific cases where each of the heptyl groups is attached to a nitrogen atom at the para-position. However, embodiments of the inventive concept are not limited thereto.

In formula 3-1, the same as described in formula 1 above can be applied to R ₁ L and FR.

The amine compound represented by formula 1 of the embodiment may be represented by any one of the compounds of the following compound group 1. The first, third, and fourth hole transport layers HTL1, HTL3, and HTL4 of the light emitting element ED of the embodiment may include at least one of amine compounds disclosed in the following compound group 1.

[ Compound group 1]

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The light emitting element ED of the inventive concept may include hole transport layers HTL1, HTL3, and HTL4 each including an amine compound represented by the above formula 1, thereby having a low refractive index.

In addition, the light emitting element ED may further include a hole transport region material in the hole transport region HTR.

In the hole transport region HTR, the above-described first to fourth hole transport layers HTL1, HTL2, HTL3, and HTL4 may include a compound represented by the following formula H-1.

Each of the first, third, and fourth hole transport layers HTL1, HTL3, and HTL4 may include an amine compound represented by the above formula 1 and a compound represented by the following formula H-1, thereby satisfying a refractive index of about 1.4 to about 1.75. By adjusting the content ratio of the compound represented by the following formula H-1 and the amine compound represented by the above formula 1, the first hole transport layer HTL1, the third hole transport layer HTL3, and the fourth hole transport layer HTL4 may have the values of the first refractive index, the third refractive index, and the fourth refractive index, respectively, as described above.

The second hole transport layer HTL2 may include a compound represented by the following formula H-1 so as to have a refractive index of about 1.8 to about 2.0.

[ H-1]

In the above formula H-1, ar _a And Ar is a group _b May each independently be a substituted or unsubstituted aryl group having from 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroaryl group having from 2 to 30 ring-forming carbon atoms.

Ar _c May be a substituted or unsubstituted aryl group having from 6 to 30 ring-forming carbon atoms.

L ₁ And L ₂ May each independently be a direct bond, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms.

p and q may each independently be an integer from 0 to 10. On the other hand, when p or q is an integer of 2 or more, a plurality of L ₁ And a plurality of L ₂ May each independently be a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms.

The compound represented by the above formula H-1 may be a monoamine compound. Alternatively, the compound represented by the above formula H-1 may be one wherein Ar _a To Ar _c At least one of them contains an amine group as a substituent. In addition, the compound represented by the above formula H-1 may be represented by Ar _a And Ar is a group _b Carbazole compound including substituted or unsubstituted carbazolyl group in at least one of them or in Ar _a And Ar is a group _b A fluorene compound containing a substituted or unsubstituted fluorenyl group in at least one of them.

The compound represented by the formula H-1 may be represented by any one of the compounds of the following group of compounds H. However, the compounds listed in the following compound group H are examples, and the compound represented by the formula H-1 is not limited to the compound represented by the following compound group H:

[ Compound group H ]

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The first to fourth hole transport layers HTL1, HTL2, HTL3, and HTL4 of the inventive concept may include a compound represented by the following formula H-1, thereby exhibiting excellent hole mobility.

In addition, the hole transport region HTR may further include a known hole transport material.

For example, the hole transport region HTR may include a phthalocyanine compound (such as copper phthalocyanine), N ¹ ,N ¹ '- ([ 1,1' -biphenyl)]-4,4' -diyl) bis (N ¹ -phenyl-N ⁴ ,N ⁴ -di-m-tolylbenzene-1, 4-diamine) (DNTPD), 4',4"- [ tris (3-methylphenyl) phenylamino group]Triphenylamine (m-MTDATA), 4' -tris (N, N-diphenylamino) triphenylamine (TDATA), 4', 4' -tris [ N- (2-naphthyl) -N-phenylamino ]Triphenylamine (2-TNATA),Poly (3, 4-ethylenedioxythiophene)/poly (4-styrenesulfonate) (PEDOT/PSS), polyaniline/dodecylbenzenesulfonic acid (PANI/DBSA), polyaniline/camphorsulfonic acid (PANI/CSA), polyaniline/poly (4-styrenesulfonate) (PANI/PSS), N ' -bis (naphthalen-1-yl) -N, N ' -diphenyl-benzidine (NPB), polyetherketone containing Triphenylamine (TPAPEK), 4-isopropyl-4 ' -methyldiphenyliodonium [ tetrakis (pentafluorophenyl) borate]Bipyrazino [2,3-f:2',3' -h]Quinoxaline-2, 3,6,7,10, 11-hexanitrile (HAT-CN), and the like.

The hole transport region HTR may include carbazole-based derivatives such as N-phenylcarbazole or polyvinylcarbazole, fluorene-based derivatives, triphenylamine-based derivatives such as N, N ' -bis (3-methylphenyl) -N, N ' -diphenyl- [1,1' -biphenyl ] -4,4' -diamine (TPD) or 4,4',4 "-tris (N-carbazolyl) triphenylamine (TCTA), N ' -bis (naphthalen-1-yl) -N, N ' -diphenyl-benzidine (NPB), 4' -cyclohexylidene-bis [ N, N-bis (4-methylphenyl) aniline ] (TAPC), 4' -bis [ N, N ' - (3-tolyl) amino ] -3,3' -dimethylbiphenyl (HMTPD), 1, 3-bis (N-carbazolyl) benzene (mCP), and the like.

In addition, the hole transport region HTR may include 9- (4-tert-butylphenyl) -3, 6-bis (triphenylsilyl) -9H-carbazole (CzSi), 9-phenyl-9H-3, 9' -dicarbazole (CCP), 1, 3-bis (1, 8-dimethyl-9H-carbazol-9-yl) benzene (mDCP), and the like.

The hole transport region HTR may include the above-described compound of the hole transport region HTR in at least one of the hole injection layer HIL, the plurality of hole transport layers HTL1, HTL2, HTL3, and HTL4, and the electron blocking layer EBL.

The hole transport region HTR may have a thickness of aboutTo about->(e.g., about->To about). When the holes are transmittedWhen the transport region HTR includes a hole injection layer HIL, the hole injection layer HIL may have, for example, aboutTo about->Is a thickness of (c). When the hole transport region HTR includes a hole transport layer, the hole transport layer may have aboutTo about->Is a thickness of (c). For example, each of the plurality of hole transport layers HTL1, HTL2, HTL3, and HTL4 may have about +.>To about->Is a thickness of (c).

For example, when the hole transport region HTR includes an electron blocking layer EBL, the electron blocking layer EBL may have aboutTo about->Is a thickness of (c). If the thicknesses of the hole transport region HTR, the hole injection layer HIL, the hole transport layer HTL, and the electron blocking layer EBL satisfy the above ranges, satisfactory hole transport properties can be achieved without significantly increasing the driving voltage.

In addition to the above materials, the hole transport region HTR may further include a charge generation material to increase conductivity. The charge generating material may be uniformly or non-uniformly dispersed in the hole transport region HTR. In an embodiment, any one of the plurality of hole transport layers HTL1, HTL2, HTL3, and HTL4 may include a charge generating material.

The charge generating material may be, for example, a p-dopant. The p-dopant may include at least one of a halogenated metal compound, a quinone derivative, a metal oxide, and a cyano-containing compound, but embodiments of the inventive concept are not limited thereto. For example, the p-dopant may include a halogenated metal compound (such as CuI or RbI), a quinone derivative (such as Tetracyanoquinodimethane (TCNQ) or 2,3,5, 6-tetrafluoro-7, 8-tetracyanoquinodimethane (F) ₄ -TCNQ)), metal oxides (such as tungsten oxide or molybdenum oxide), cyano-containing compounds (such as bipyrazino [2,3-f:2',3' -h)]Quinoxaline-2, 3,6,7,10, 11-hexanitrile (HAT-CN) or 4- [ [2, 3-bis [ cyano- (4-cyano-2, 3,5, 6-tetrafluorophenyl) methylene]Cyclopropylidene group]-cyanomethyl group]-2,3,5, 6-tetrafluorobenzonitrile (NDP 9)), etc., but embodiments of the inventive concept are not limited thereto.

As described above, the hole transport region HTR may include at least one of a buffer layer (not shown) and an electron blocking layer EBL in addition to the hole injection layer HIL and the plurality of hole transport layers HTL1, HTL2, HTL3, and HTL 4. The buffer layer (not shown) may compensate for the resonance distance according to the wavelength of light emitted from the emission layer EML, and may thus increase the light emission efficiency. The material that may be included in the hole transport region HTR may be used as a material included in a buffer layer (not shown). The electron blocking layer EBL is a layer for preventing electrons from being injected from the electron transport region ETR to the hole transport region HTR.

The emission layer EML is disposed on the hole transport region HTR. The emissive layer EML may have, for example, aboutTo aboutOr about->To about->Is a thickness of (c). The emission layer EML may have a light emitting layer composed ofA single layer formed of a single material, a single layer formed of a plurality of different materials, or a multi-layer structure having a plurality of layers formed of a plurality of different materials.

In the light emitting element ED of the embodiment, the emission layer EML may include anthracene derivatives, pyrene derivatives, fluoranthene derivatives,Derivatives, dihydrobenzanthracene derivatives or benzo [9,10]Phenanthrene derivatives. Specifically, the emission layer EML may include an anthracene derivative or a pyrene derivative.

In each of the light emitting elements ED of the embodiments shown in fig. 3 to 9, the emission layer EML may include a host and a dopant, and the emission layer EML may include a compound represented by the following formula E-1. The compound represented by the following formula E-1 can be used as a fluorescent host material.

[ E-1]

In formula E-1, R ₃₁ To R ₄₀ May each independently be a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted silyl group, a substituted or unsubstituted thio group, a substituted or unsubstituted oxy group, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, and may optionally be bonded to an adjacent group to form a ring. On the other hand, R ₃₁ To R ₄₀ May optionally be bonded to an adjacent group to form a saturated or unsaturated hydrocarbon ring, a saturated or unsaturated heterocyclic ring.

In formula E-1, c and d may each independently be an integer from 0 to 5.

Formula E-1 may be represented by any one of the following compounds E1 to E19:

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in an embodiment, the emission layer EML may include a compound represented by the following formula E-2a or formula E-2 b. A compound represented by the following formula E-2a or formula E-2b may be used as the phosphorescent host material.

[ E-2a ]

In formula E-2a, a may be an integer of 0 to 10, L _a May be a direct bond, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms. On the other hand, when a is an integer of 2 or more, a plurality of L _a May each independently be a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms.

In formula E-2a, A ₁ To A ₅ Can each independently be N or CR _i 。R _a To R _i May each independently be a hydrogen atom, a deuterium atom, a substituted or unsubstituted amine group, a substituted or unsubstituted thio group, a substituted or unsubstituted oxy group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, and may optionally be bonded to an adjacent group to form a ring. R is R _a To R _i May be bonded to an adjacent group to form a hydrocarbon ring or a heterocyclic ring containing N, O, S or the like as a ring-forming atom.

On the other hand, in formula E-2a, a compound selected fromFrom A ₁ To A ₅ Two or three of them may be N and the others may be CR _i 。

[ E-2b ]

In formula E-2b, cbz1 and Cbz2 may each independently be an unsubstituted carbazolyl group or a carbazolyl group substituted with an aryl group having 6 to 30 ring-forming carbon atoms. L (L) _b Is a direct bond, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms. On the other hand, b is an integer of 0 to 10, and when b is an integer of 2 or more, a plurality of L _b May each independently be a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms.

The compound represented by the formula E-2a or the formula E-2b may be represented by any one of the compounds of the following group of compounds E-2. However, the compounds listed in the following compound group E-2 are exemplary, and the compounds represented by the formula E-2a or the formula E-2b are not limited to the compounds represented in the following compound group E-2.

[ Compound group E-2]

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The emission layer EML may further include a general material known in the art as a host material. For example, the emission layer EML may include a bis (4- (9H-carbazol-9-yl) phenyl) diphenylsilane (BCPDS), (4- (1- (4- (diphenylamino) phenyl) cyclohexyl) phenyl) diphenyl-Phosphine Oxide (POPCPA), bis [2- (diphenylphosphino) phenyl)]Ether oxide (DPEPO), 4' -bis (carbazol-9-yl) biphenyl (CBP), 1, 3-bis (carbazol-9-yl) benzene (mCP), 2, 8-bis (diphenylphosphoryl) dibenzo [ b, d ]]Furan (PPF), 4',4 "-tris (carbazol-9-yl) triphenylamine (TCTA) and 1,3, 5-tris (1-phenyl-1H-benzo [ d)]At least one of imidazol-2-yl) benzene (TPBi) as a host material. However, embodiments of the inventive concept are not limited thereto, e.g., tris (8-hydroxyquinoline) aluminum (Alq ₃ ) 9, 10-bis (naphthalen-2-yl) Anthracene (ADN), 2-tert-butyl-9, 10-bis (naphthalen-2-yl) anthracene (TBADN), distyrylarylide (DSA), 4 '-bis (9-carbazolyl) -2,2' -dimethyl-biphenyl (CDBP), 2-methyl-9, 10-bis (naphthalen-2-yl) anthracene (MADN), hexaphenylcyclotriphosphazene (CP 1), 1, 4-bis (triphenylsilyl) benzene (UGH) ₂ ) Hexaphenyl cyclotrisiloxane (DPSiO) ₃ ) Octaphenyl cyclotetrasiloxane (DPSiO) ₄ ) Etc. may be used as host materials.

The emission layer EML may include a compound represented by the following formula M-a or formula M-b. A compound represented by the following formula M-a or formula M-b may be used as the phosphorescent dopant material.

[ M-a ]

In the above formula M-a, Y ₁ To Y ₄ And Z ₁ To Z ₄ Can be each independently CR ₁ Or N, R ₁ To R ₄ May each independently be a hydrogen atom, a deuterium atom, a substituted or unsubstituted amine group, a substituted or unsubstituted thio group, a substituted or unsubstituted oxy group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, and may optionally be bonded to an adjacent group to form a ring. In formula M-a, M is 0 or 1, and n is 2 or 3.In formula M-a, n is 3 when M is 0, and n is 2 when M is 1.

The compound represented by formula M-a may be used as a phosphorescent dopant.

The compound represented by the formula M-a may be represented by any one of the following compounds M-a1 to M-a 25. However, the following compounds M-a1 to M-a25 are exemplary, and the compounds represented by the formula M-a are not limited to the compounds represented by the following compounds M-a1 to M-a 25.

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The compounds M-a1 and M-a2 may be used as red dopant materials, and the compounds M-a3 to M-a7 may be used as green dopant materials.

[ M-b ]

In formula M-b, Q ₁ To Q ₄ Each independently is C or N, and C1 to C4 are each independently a substituted or unsubstituted hydrocarbon ring having 5 to 30 ring-forming carbon atoms or a substituted or unsubstituted heterocyclic ring having 2 to 30 ring-forming carbon atoms. L (L) ₂₁ To L ₂₄ Are all independently a direct bond, Substituted or unsubstituted divalent alkyl groups having 1 to 20 carbon atoms, substituted or unsubstituted arylene groups having 6 to 30 ring-forming carbon atoms, or substituted or unsubstituted heteroarylene groups having 2 to 30 ring-forming carbon atoms, and e1 toe4 are each independently 0 or 1.R is R ₃₁ To R ₃₉ Each independently is a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amine group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, and is optionally bonded to an adjacent group to form a ring, and d1 to d4 are each independently integers of 0 to 4.

The compound represented by formula M-b may be used as a blue phosphorescent dopant or a green phosphorescent dopant.

The compound represented by the formula M-b may be represented by any one of the following compounds M-b-1 to M-b-11. However, the following compounds are examples, and the compounds represented by the formula M-b are not limited to the compounds M-b-1 to M-b-11:

r, R among the compounds ₃₈ And R is ₃₉ May each independently be a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amine group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms.

The emission layer EML may include a compound represented by any one of the following formulas F-a to F-c. Compounds represented by the following formula F-a or formula F-c may be used as the fluorescent dopant material.

[ F-a ]

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In the above formula F-a, R is selected from _a To R _j Two of which may each be independently substituted with-NAr ₁ Ar ₂ 。R _a To R _j The missing of the Chinese medicineSubstituted by: -NAr ₁ Ar ₂ Each of the other groups of (a) may independently be a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amine group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. at-NAr ₁ Ar ₂ Ar in (1) ₁ And Ar is a group ₂ May each independently be a substituted or unsubstituted aryl group having from 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroaryl group having from 2 to 30 ring-forming carbon atoms. For example, ar ₁ And Ar is a group ₂ At least one of which may be a heteroaryl group containing O or S as a ring-forming atom.

[ F-b ]

In the above formula F-b, ar ₁ To Ar ₄ May each independently be a substituted or unsubstituted aryl group having from 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroaryl group having from 2 to 30 ring-forming carbon atoms.

In formula F-b, R _a And R is _b May each independently be a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, and may optionally be bonded to an adjacent group to form a ring.

In formula F-b, U and V may each independently be a substituted or unsubstituted hydrocarbon ring having 5 to 30 ring-forming carbon atoms or a substituted or unsubstituted heterocyclic ring having 2 to 30 ring-forming carbon atoms.

In formula F-b, the number of rings represented by U and V may each independently be 0 or 1. For example, in the formula F-b, it means that when the number of U or V is 1, one ring constitutes a condensed ring at the portion indicated by U or V, and when the number of U or V is 0, the ring indicated by U or V is not present. Specifically, when the number of U is 0 and the number of V is 1, or when the number of U is 1 and the number of V is 0, the condensed ring having a fluorene core in formula F-b may be a ring compound having four rings. In addition, when the number of both U and V is 0, the condensed ring having a fluorene core in formula F-b may be a ring compound having three rings. In addition, when the number of both U and V is 1, the condensed ring having a fluorene core in formula F-b may be a ring compound having five rings.

[ F-c ]

In formula F-c, A ₁ And A ₂ Can each independently be O, S, se or NR _m And R is _m May be a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. R is R ₁ To R ₁₁ Each independently is a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amine group, a substituted or unsubstituted boron group, a substituted or unsubstituted oxygen group, a substituted or unsubstituted sulfur group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, and is optionally bonded to an adjacent group to form a ring.

In formula F-c, A ₁ And A ₂ Each independently may be bonded to a substituent of an adjacent ring to form a condensed ring. For example, when A ₁ And A ₂ Are each independently NR _m When A is ₁ Can be bonded to R ₄ Or R is ₅ To form a ring. In addition, A ₂ Can be bonded to R ₇ Or R is ₈ To form a ring.

In an embodiment, the emission layer EML may include styryl derivatives (e.g., 1, 4-bis [2- (3-N-ethylcarbazolyl) vinyl ] benzene (BCzVB), 4- (di-p-tolylamino) -4' - [ (di-p-tolylamino) styryl ] stilbene (DPAVB), N- (4- ((E) -2- (6- ((E) -4- (diphenylamino) styryl) naphthalen-2-yl) vinyl) phenyl) -N-phenylaniline (N-BDAVBi), and 4,4' -bis [2- (4- (N, N-diphenylamino) phenyl) vinyl ] biphenyl (DPAVBi)), perylene and derivatives thereof (e.g., 2,5,8, 11-tetra-t-butylperylene (TBP)), pyrene and derivatives thereof (e.g., 1' -dipyrene, 1, 4-dipyrene benzene, 1, 4-bis (N, N-diphenylamino) pyrene), and the like as known dopant materials.

The emission layer EML may include a known phosphorescent dopant material. For example, a metal complex including iridium (Ir), platinum (Pt), osmium (Os), gold (Au), titanium (Ti), zirconium (Zr), hafnium (Hf), europium (Eu), terbium (Tb), or thulium (Tm) may be used as the phosphorescent dopant. Specifically, bis (4, 6-difluorophenylpyridine-N, C2') picolinated iridium (III) (FIrpic), bis (2, 4-difluorophenylpyridine) -tetrakis (1-pyrazolyl) borate iridium (III) (FIr) ₆ ) Or octaethylporphyrin platinum (PtOEP) may be used as phosphorescent dopant. However, embodiments of the inventive concept are not limited thereto.

The emission layer EML may include a quantum dot material. The core of the quantum dot may be selected from the group consisting of group II-VI compounds, group III-VI compounds, group I-III-VI compounds, group III-V compounds, group III-II-V compounds, group IV-VI compounds, group IV elements, group IV compounds, and combinations thereof.

The group II-VI compound may be selected from the group consisting of binary compounds selected from the group consisting of CdSe, cdTe, cdS, znS, znSe, znTe, znO, hgS, hgSe, hgTe, mgSe, mgS and mixtures thereof, ternary compounds selected from the group consisting of CdSeS, cdSeTe, cdSTe, znSeS, znSeTe, znSTe, hgSeS, hgSeTe, hgSTe, cdZnS, cdZnSe, cdZnTe, cdHgS, cdHgSe, cdHgTe, hgZnS, hgZnSe, hgZnTe, mgZnSe, mgZnS and mixtures thereof, and quaternary compounds selected from the group consisting of CdZnSeS, cdZnSeTe, cdZnSTe, cdHgSeS, cdHgSeTe, cdHgSTe, hgZnSeS, hgZnSeTe, hgZnSTe and mixtures thereof.

The III-VI compounds may include binary compounds (such as In ₂ S ₃ Or In ₂ Se ₃ ) Ternary compounds (such as InGaS ₃ Or InGaSe ₃ ) Or any combination thereof.

The group I-III-VI compound may be selected from: ternary compounds selected from AgInS, agInS ₂ 、CuInS、CuInS ₂ 、AgGaS ₂ 、CuGaS ₂ 、CuGaO ₂ 、AgGaO ₂ 、AgAlO ₂ And mixtures thereof; quaternary compounds, e.g. AgInGaS ₂ Or CuInGaS ₂ 。

The III-V compounds may be selected from the group consisting of binary compounds selected from the group consisting of GaN, gaP, gaAs, gaSb, alN, alP, alAs, alSb, inN, inP, inAs, inSb and mixtures thereof, ternary compounds selected from the group consisting of GaNP, gaNAs, gaNSb, gaPAs, gaPSb, alNP, alNAs, alNSb, alPAs, alPSb, inGaP, inAlP, inNP, inNAs, inNSb, inPAs, inPSb and mixtures thereof, and quaternary compounds selected from the group consisting of GaAlNP, gaAlNAs, gaAlNSb, gaAlPAs, gaAlPSb, gaInNP, gaInNAs, gaInNSb, gaInPAs, gaInPSb, inAlNP, inAlNAs, inAlNSb, inAlPAs, inAlPSb and mixtures thereof. In another aspect, the III-V compounds may also include a group II metal. For example, inZnP and the like may be selected as the group III-II-V compound.

The group IV-VI compound may be selected from the group consisting of binary compounds selected from the group consisting of SnS, snSe, snTe, pbS, pbSe, pbTe and mixtures thereof, ternary compounds selected from the group consisting of SnSeS, snSeTe, snSTe, pbSeS, pbSeTe, pbSTe, snPbS, snPbSe, snPbTe and mixtures thereof, and quaternary compounds selected from the group consisting of SnPbSSe, snPbSeTe, snPbSTe and mixtures thereof. The group IV element may be selected from the group consisting of Si, ge, and mixtures thereof. The group IV compound may be a binary compound selected from the group consisting of SiC, siGe, and mixtures thereof.

In this case, the binary, ternary or quaternary compound may be present in the particles in a uniform concentration distribution, or may be present in the same particle in a partially different concentration distribution. In addition, the quantum dots may have a core/shell structure in which one quantum dot surrounds another quantum dot. The core/shell structure may have a concentration gradient in which the concentration of the element present in the shell decreases toward the core.

In some embodiments, the quantum dots may have the core/shell structure described above including a core comprising nanocrystals and a shell surrounding the core. The shell of the quantum dot may serve as a protective layer that prevents chemical denaturation of the core to preserve semiconducting properties, and/or may serve as a charged layer that imparts electrophoretic properties to the quantum dot. The shell may be a single layer or multiple layers. Examples of shells of quantum dots may include metal or non-metal oxides, semiconductor compounds, or combinations thereof.

For example, examples of metal or nonmetal oxides may include binary compounds (such as SiO ₂ 、Al ₂ O ₃ 、TiO ₂ 、ZnO、MnO、Mn ₂ O ₃ 、Mn ₃ O ₄ 、CuO、FeO、Fe ₂ O ₃ 、Fe ₃ O ₄ 、CoO、Co ₃ O ₄ And NiO) or ternary compounds (such as MgAl ₂ O ₄ 、CoFe ₂ O ₄ 、NiFe ₂ O ₄ And CoMn ₂ O ₄ ) Embodiments of the inventive concept are not limited thereto.

Further, examples of the semiconductor compound may include CdS, cdSe, cdTe, znS, znSe, znTe, znSeS, znTeS, gaAs, gaP, gaSb, hgS, hgSe, hgTe, inAs, inP, inGaP, inSb, alAs, alP, alSb and the like, but embodiments of the inventive concept are not limited thereto.

The quantum dot may have a full width at half maximum (FWHM) of an emission wavelength spectrum of about 45nm or less (preferably, about 40nm or less, more preferably, about 30nm or less), and may improve color purity or color reproducibility within the above range. In addition, light emitted through such quantum dots is emitted in all directions, and thus a wide viewing angle can be improved.

In addition, the form of the quantum dot is not particularly limited as long as it is a form commonly used in the art, and more specifically, quantum dots in the form of spherical, pyramidal, multi-arm, or cubic nanoparticles, nanotubes, nanowires, nanofibers, nanoplatelets, or the like may be used.

The quantum dots may control the color of the emitted light according to their particle size. Accordingly, the quantum dots may have various light emission colors such as blue, red, and green.

In each of the light emitting elements ED of the embodiments shown in fig. 3 to 9, an electron transport region ETR is provided on the emission layer EML. The electron transport region ETR may include at least one of a hole blocking layer HBL, an electron transport layer ETL, and an electron injection layer EIL, but embodiments of the inventive concept are not limited thereto.

The electron transport region ETR may have a single layer formed of a single material, a single layer formed of a plurality of different materials, or a multi-layer structure including a plurality of layers formed of a plurality of different materials.

For example, the electron transport region ETR may have a single-layer structure of the electron injection layer EIL or the electron transport layer ETL, and may have a single-layer structure formed of an electron injection material and an electron transport material. In addition, the electron transport region ETR may have a single layer structure formed of a plurality of different materials, or may have a structure in which an electron transport layer ETL/an electron injection layer EIL, a hole blocking layer HBL/an electron transport layer ETL/an electron injection layer EIL are sequentially stacked from an emission layer EML, but embodiments of the inventive concept are not limited thereto. The electron transport region ETR may have, for example, aboutTo about->Is a thickness of (c).

The electron transport region ETR may be formed by using various methods such as a vacuum deposition method, a spin coating method, a casting method, a langmuir-blodgett (LB) method, an inkjet printing method, a laser printing method, and a Laser Induced Thermal Imaging (LITI) method.

The electron transport region ETR may include a compound represented by the following formula ET-1:

[ ET-1]

In formula ET-1, X ₁ To X ₃ At least one of them is N and the others are CR _a 。R _a May be a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. Ar (Ar) ₁ To Ar ₃ May each independently be a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms.

In formula ET-1, a to c may each independently be an integer of 0 to 10. In formula ET-1, L ₁ To L ₃ May each independently be a direct bond, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms. On the other hand, when a to c are integers of 2 or more, L ₁ To L ₃ May each independently be a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms.

The electron transport region ETR may include an anthracene compound. However, embodiments of the inventive concept are not limited thereto, and the electron transport region ETR may include, for example, tris (8-hydroxyquinoline) aluminum (Alq ₃ ) 1,3, 5-tris [ (3-pyridyl) -benzene-3-yl]Benzene, 2,4, 6-tris (3' - (pyridin-3-yl) biphenyl-3-yl) -1,3, 5-triazine, 2- (4- (N-phenylbenzimidazol-1-yl) phenyl) -9, 10-dinaphthyl anthracene, 1,3, 5-tris (1-phenyl-1H-benzo [ d ] ]Imidazol-2-yl) benzene (TPBi), 2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline (BCP), 4, 7-diphenyl-1, 10-phenanthroline (Bphen), 3- (4-diphenyl) -4-phenyl-5-tert-butylphenyl-1, 2, 4-Triazole (TAZ), 4- (naphthalen-1-yl) -3,5-diphenyl-4H-1, 2, 4-triazole (NTAZ), 2- (4-biphenyl) -5- (4-tert-butylphenyl) -1,3, 4-oxadiazole ^t Bu-PBD), bis (2-methyl-8-hydroxyquinoline-N1, O8) - (1, 1' -biphenyl-4-hydroxy) aluminum (BAlq), bis (benzoquinoline-10-hydroxy) beryllium (Bebq) ₂ ) 9, 10-bis (naphthalen-2-yl) Anthracene (ADN), 1, 3-bis [3, 5-bis (pyridin-3-yl) phenyl]Benzene (BmPyPhB) or mixtures thereof.

In addition, the electron transport region ETR may include a metal halide (such as LiF, naCl, csF, rbCl, rbI, cuI or KI), a lanthanide metal (such as Yb), and a co-deposited material of the metal halide and the lanthanide metal. For example, the electron transport region ETR may include KI: yb, rbI: yb, liF: yb, or the like as the co-deposited material. On the other hand, the electron transport region ETR may use, for example, li ₂ Metal oxide of O or BaO, or lithium 8-hydroxy-quinoline (Liq), etc., but embodiments of the inventive concept are not limited thereto. The electron transport region ETR may also be formed of a mixed material of an electron transport material and an insulating organic metal salt. The organometallic salt can be a material having an energy bandgap of about 4eV or greater. In particular, the organometallic salts may include, for example, metal acetates, metal benzoates, metal acetoacetates, metal acetylacetonates, or metal stearates.

In addition to the above materials, the electron transport region ETR may further include at least one of 2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline (BCP), diphenyl (4- (triphenylsilyl) phenyl) phosphine oxide (TSPO 1), and 4, 7-diphenyl-1, 10-phenanthroline (Bphen), but embodiments of the inventive concept are not limited thereto.

The electron transport region ETR may include a compound of the above-described electron transport region ETR in at least one of the electron injection layer EIL, the electron transport layer ETL, and the hole blocking layer HBL.

When the electron transport region ETR includes an electron transport layer ETL, the electron transport layer ETL may have a thickness of aboutTo about(e.g., about->To about->) Is a thickness of (c). If the thickness of the electron transport layer ETL satisfies the above range, satisfactory electron transport characteristics can be obtained without significantly increasing the driving voltage. When the electron transport region ETR includes an electron injection layer EIL, the electron injection layer EIL may have about +.>To about->(e.g., about->To about->) Is a thickness of (c). If the thickness of the electron injection layer EIL satisfies the above range, satisfactory electron injection characteristics can be obtained without significantly increasing the driving voltage.

The second electrode EL2 is disposed on the electron transport region ETR. The second electrode EL2 may be a common electrode. The second electrode EL2 may be a cathode or an anode, but embodiments of the inventive concept are not limited thereto. For example, when the first electrode EL1 is an anode, the second electrode EL2 may be a cathode, and when the first electrode EL1 is a cathode, the second electrode EL2 may be an anode.

The second electrode EL2 may be a transmissive electrode, a transflective electrode, or a reflective electrode. When the second electrode EL2 is a transmissive electrode, the second electrode EL2 may be formed of a transparent metal oxide (e.g., indium Tin Oxide (ITO), indium Zinc Oxide (IZO), zinc oxide (ZnO), indium Tin Zinc Oxide (ITZO), or the like).

When the second electrode EL2 is a transflective electrode or a reflective electrode, the second electrode EL2 may include Ag, mg, cu, al, pt, pd, au, ni, nd, ir, cr, li, ca, liF, mo, ti, yb, W, a compound or mixture thereof (e.g., agMg, agYb, or MgYb), or a material having a multilayer structure such as LiF/Ca or LiF/Al. Alternatively, the second electrode EL2 may have a multilayer structure including a reflective film or a transflective film formed of the above-described materials, and a transparent conductive film formed of ITO, IZO, znO, ITZO or the like. For example, the second electrode EL2 may include the above-described metal materials, a combination of at least two of the above-described metal materials, an oxide of the above-described metal materials, or the like.

Although not shown, the second electrode EL2 may be connected to an auxiliary electrode. If the second electrode EL2 is connected to the auxiliary electrode, the resistance of the second electrode EL2 can be reduced.

On the other hand, the cap layer CPL may also be provided on the second electrode EL2 of the light emitting element ED of the embodiment. The cover layer CPL may comprise multiple layers or a single layer. In an embodiment, the capping layer CPL may include the amine compound described above for the embodiment.

In an embodiment, the capping layer CPL may be an organic layer or an inorganic layer. For example, when the capping layer CPL contains an inorganic material, the inorganic material may include an alkali metal compound (e.g., liF), an alkaline earth metal compound (e.g., mgF) ₂ )、SiON、SiN _x 、SiO _y Etc.

For example, when the capping layer CPL includes an organic material, the organic material may include alpha-NPD, NPB, TPD, m-MTDATA, alq ₃ CuPc, N4' -tetra (biphenyl-4-yl) biphenyl-4, 4' -diamine (TPD 15), 4',4 "-tris (carbazol-9-yl) triphenylamine (TCTA), etc., or may include an epoxy resin or an acrylate such as a methacrylate. However, embodiments of the inventive concept are not limited thereto, and the capping layer CPL may include at least one of the following compounds P1 to P5:

on the other hand, the refractive index of the cover layer CPL may be about 1.6 or more. Specifically, the refractive index of the capping layer CPL may be 1.6 or more with respect to light in the wavelength range of about 550nm to about 660 nm.

Each of fig. 10 and 12 is a cross-sectional view of a display device according to an embodiment, and fig. 11 is a cross-sectional view of a display element layer according to an embodiment. Hereinafter, in describing the display device of the embodiment with reference to fig. 10 to 12, the repetitive features that have been described in fig. 1 to 9 will not be described again, but differences thereof will be mainly described.

Referring to fig. 10, the display device DD according to the embodiment may include a display panel DP including a display element layer DP-ED, a light control layer CCL disposed on the display panel DP, and a color filter layer CFL.

In the embodiment shown in fig. 10, the display panel DP may include a base layer BS, a circuit layer DP-CL and a display element layer DP-ED disposed on the base layer BS, and the display element layer DP-ED may include a light emitting element ED.

The light emitting element ED may include a first electrode EL1, a hole transport region HTR disposed on the first electrode EL1, an emission layer EML disposed on the hole transport region HTR, an electron transport region ETR disposed on the emission layer EML, and a second electrode EL2 disposed on the electron transport region ETR. On the other hand, the structure of the light emitting element of fig. 3 to 9 as described above can be similarly applied to the structure of the light emitting element ED shown in fig. 10.

Referring to fig. 10, an emission layer EML may be disposed in an opening OH defined in the pixel defining film PDL. For example, the emission layer EML divided by the pixel defining film PDL and disposed corresponding to each of the light emitting areas PXA-R, PXA-G and PXA-B may emit light within the same wavelength range. In the display device DD of the embodiment, the emission layer EML may emit blue light. On the other hand, unlike the illustrated configuration, in an embodiment, the emission layer EML may be provided as a common layer in the entire light emitting areas PXA-R, PXA-G and PXA-B.

The light control layer CCL may be disposed on the display panel DP. The light control layer CCL may comprise a light converting body. The light converter may be a quantum dot, phosphor, or the like. The light converting body may emit the supplied light by converting a wavelength of the supplied light. That is, the light control layer CCL may be a layer containing quantum dots or a layer containing phosphor.

The light control layer CCL may include a plurality of light control parts CCP1, CCP2, and CCP3. The light control parts CCP1, CCP2, and CCP3 may be spaced apart from each other.

Referring to fig. 10, the partition pattern BMP may be disposed between the light control parts CCP1, CCP2, and CCP3 spaced apart from each other, but embodiments of the inventive concept are not limited thereto. Fig. 10 illustrates that the separation pattern BMP is not overlapped with the light control parts CCP1, CCP2, and CCP3, but at least a portion of edges of the light control parts CCP1, CCP2, and CCP3 may be overlapped with the separation pattern BMP.

The light control layer CCL may include a first light control part CCP1, a second light control part CCP2, and a third light control part CCP3, the first light control part CCP1 including first quantum dots QD1 converting first color light supplied from the light emitting element ED into second color light, the second light control part CCP2 including second quantum dots QD2 converting the first color light into third color light, and the third light control part CCP3 transmitting the first color light.

In an embodiment, the first light control part CCP1 may provide red light as the second color light, and the second light control part CCP2 may provide green light as the third color light. The third light control part CCP3 may provide blue light by transmitting blue light as the first color light provided from the light emitting element ED. For example, the first quantum dot QD1 may be a red quantum dot and the second quantum dot QD2 may be a green quantum dot. Regarding the quantum dots QD1 and QD2, the same description as above may be applied.

In addition, the light control layer CCL may also comprise a diffuser SP. The first light control part CCP1 may include first quantum dots QD1 and a diffuser SP, the second light control part CCP2 may include second quantum dots QD2 and a diffuser SP, and the third light control part CCP3 may not include any quantum dots but include a diffuser SP.

The scatterers SP may be inorganic particles. For example, the diffuser SP may include TiO ₂ 、ZnO、Al ₂ O ₃ 、SiO ₂ And at least one of hollow spherical silica. The diffuser SP may be packagedIncluding TiO ₂ 、ZnO、Al ₂ O ₃ 、SiO ₂ And hollow spherical silica, or may be selected from TiO ₂ 、ZnO、Al ₂ O ₃ 、SiO ₂ And a mixture of at least two materials among hollow spherical silica.

The first, second and third light control parts CCP1, CCP2 and CCP3 may include matrix resins BR1, BR2 and BR3 in which quantum dots QD1 and QD2 and a diffuser SP are dispersed, respectively. In an embodiment, the first light control part CCP1 may include first quantum dots QD1 and a diffuser SP dispersed in a first matrix resin BR1, the second light control part CCP2 may include second quantum dots QD2 and a diffuser SP dispersed in a second matrix resin BR2, and the third light control part CCP3 may include a diffuser SP dispersed in a third matrix resin BR3. The matrix resins BR1, BR2, and BR3 are media in which the quantum dots QD1 and QD2 and the scatterer SP are dispersed, and may be formed of various resin components which may be generally referred to as binders. For example, the base resins BR1, BR2, and BR3 may be acrylic resins, urethane resins, silicone resins, epoxy resins, or the like. The matrix resins BR1, BR2, and BR3 may be transparent resins. In an embodiment, the first, second, and third matrix resins BR1, BR2, and BR3 may be the same or different from each other.

The light control layer CCL may include a barrier layer BFL1. The barrier layer BFL1 may be used to prevent permeation of moisture and/or oxygen (hereinafter, referred to as "moisture/oxygen"). The blocking layer BFL1 may be disposed on the light control parts CCP1, CCP2, and CCP3 to block the light control parts CCP1, CCP2, and CCP3 from being exposed to moisture/oxygen. On the other hand, the blocking layer BFL1 may cover the light control parts CCP1, CCP2, and CCP3. In addition, the blocking layer BFL2 may be disposed between the light control parts CCP1, CCP2, and CCP3 and the filters CF1, CF2, and CF 3. In the drawings, for convenience of illustration, the blocking layer BFL2 is illustrated as a part of the color filter layer CFL.

The barrier layers BFL1 and BFL2 may include at least one inorganic layer. That is, the barrier layers BFL1 and BFL2 may include an inorganic material. For example, the barrier layers BFL1 and BFL2 may include silicon nitride, aluminum nitride, zirconium nitride, titanium nitride, hafnium nitride, tantalum nitride, silicon oxide, aluminum oxide, titanium oxide, tin oxide, cerium oxide, silicon oxynitride, a metal film ensuring transmittance, and the like. On the other hand, the barrier layers BFL1 and BFL2 may further include an organic film. The barrier layers BFL1 and BFL2 may be formed of a single layer or multiple layers.

In the display device DD of an embodiment, a color filter layer CFL may be disposed on the light control layer CCL. For example, the color filter layer CFL may be disposed directly on the light control layer CCL. In this case, the barrier layer BFL2 may be omitted.

The color filter layer CFL may include a light shielding member BM and filters CF1, CF2, and CF3. The color filter layer CFL may include a first filter CF1 configured to transmit the second color light, a second filter CF2 configured to transmit the third color light, and a third filter CF3 configured to transmit the first color light. For example, the first filter CF1 may be a red filter, the second filter CF2 may be a green filter, and the third filter CF3 may be a blue filter. The filters CF1, CF2 and CF3 may each include a polymer photosensitive resin, and a pigment or dye. The first filter CF1 may include a red pigment or dye, the second filter CF2 may include a green pigment or dye, and the third filter CF3 may include a blue pigment or dye. On the other hand, embodiments of the inventive concept are not limited thereto, and the third filter CF3 may not include pigment or dye. The third filter CF3 may include a polymer photosensitive resin, and may not include a pigment or dye. The third filter CF3 may be transparent. The third filter CF3 may be formed of a transparent photosensitive resin.

Further, in the embodiment, the first filter CF1 and the second filter CF2 may be yellow filters. The first filter CF1 and the second filter CF2 may not be separated but provided as one filter.

The light shielding member BM may be a black matrix. The light shielding member BM may include an organic light shielding material or an inorganic light shielding material containing a black pigment or dye. The light shielding member BM may prevent light leakage, and may separate boundaries between adjacent filters CF1, CF2, and CF 3. In addition, in the embodiment, the light shielding member BM may be formed of a blue filter.

The first to third filters CF1, CF2 and CF3 may be disposed corresponding to the red, green and blue light emitting areas PXA-R, PXA-G and PXA-B, respectively.

The base substrate BL may be disposed on the color filter layer CFL. The base substrate BL may be a member providing a base surface on which the color filter layer CFL, the light control layer CCL, etc. are disposed. The base substrate BL may be a glass substrate, a metal substrate, a plastic substrate, or the like. However, embodiments of the inventive concept are not limited thereto, and the base substrate BL may be an inorganic layer, an organic layer, or a composite material layer. In addition, unlike the illustrated configuration, in the embodiment, the base substrate BL may be omitted.

The display element layer DP-ED-1 of the embodiment shown in fig. 11 may further include resonance auxiliary layers SL-R, SL-G and SL-B disposed between the emission layers EML-R, EML-G and EML-B, respectively, and the hole transport region HTR. In an embodiment, the first to third emission layers EML-R, EML-G and EML-B may be disposed to be spaced apart from each other in a plane. The first emission layer EML-R may be disposed to be spaced apart from the second emission layer EML-G, and the second emission layer EML-G may be disposed to be spaced apart from the third emission layer EML-B. The resonance auxiliary layers SL-R, SL-G and SL-B may be layers that help light emitted from the emission layers EML-R, EML-G and EML-B constructively interfere with light reflected in the first electrode EL1 by adjusting the distance between the first electrode EL1 and the second electrode EL 2.

The display device DD of the embodiment may have a structure in which light emitted from the emission layers EML-R, EML-G and EML-B resonates. The resonant structure may have a resonant distance that varies with the wavelength of light emitted from the emission layers EML-R, EML-G and EML-B. Accordingly, the resonance auxiliary layers SL-R, SL-G and SL-B may be disposed on lower portions of the emission layers EML-R, EML-G and EML-B, respectively, to adjust the resonance distance. The resonance auxiliary layers SL-R, SL-G and SL-B may have different thicknesses according to the wavelength of the light beams emitted from the emission layers EML-R, EML-G and EML-B. Thickness T of first resonance auxiliary layer SL-R _RS May be larger than the second resonance auxiliary layer SL-GThickness T of (2) _GS And thickness T of the second resonance auxiliary layer SL-G _GS May be greater than the thickness T of the third resonance auxiliary layer SL-B _BS . That is, the thickness may be reduced in the order of the first, second, and third resonance auxiliary layers SL-R, SL-G, and SL-B. However, this is merely exemplary, but embodiments of the inventive concept are not limited thereto, and in embodiments, when the emission layers EML-R, EML-G and EML-B emit light of the same wavelength, the resonance auxiliary layers SL-R, SL-G and SL-B may have the same thickness.

Fig. 12 is a cross-sectional view of a portion of a display device DD-TD according to an embodiment. Fig. 12 shows a cross-sectional view of a portion corresponding to the display panel DP of fig. 10. In the display device DD-TD of the embodiment, the light emitting element ED-BT may include a plurality of light emitting structures OL-B1, OL-B2, and OL-B3. The light emitting element ED-BT may include a first electrode EL1 and a second electrode EL2 facing each other and a plurality of light emitting structures OL-B1, OL-B2, and OL-B3 sequentially stacked in a thickness direction between the first electrode EL1 and the second electrode EL 2. The light emitting structures OL-B1, OL-B2, and OL-B3 may each include an emission layer EML (fig. 10) and hole and electron transport regions HTR (fig. 10) and ETR (fig. 10), with the emission layer EML being positioned between the hole and electron transport regions HTR and ETR.

That is, the light emitting elements ED to BT included in the display device DD to TD of the embodiment may be light emitting elements having a series structure and including a plurality of emission layers.

In the embodiment shown in fig. 12, the light beams emitted from the light emitting structures OL-B1, OL-B2, and OL-B3, respectively, may be all blue light. However, embodiments of the inventive concept are not limited thereto, and light beams emitted from the light emitting structures OL-B1, OL-B2, and OL-B3, respectively, may have wavelength ranges different from each other. For example, the light emitting element ED-BT including a plurality of light emitting structures OL-B1, OL-B2 and OL-B3 emitting light beams having different wavelength ranges from each other may emit white light.

The charge generation layers CGL1 and CGL2 may be disposed between adjacent light emitting structures OL-B1, OL-B2, and OL-B3. The charge generation layers CGL1 and CGL2 may include a p-type charge generation layer and/or an n-type charge generation layer.

At least one of the light emitting structures OL-B1, OL-B2, and OL-B3 included in the display device DD-TD of the embodiment may include the above-described amine compound of the embodiment.

The light emitting element ED according to the embodiment may include a light emitting element having a low refractive index and satisfying about 6.0x10 ^-5 cm/(V.s) to about 10.0x10 ^-4 A first hole transport layer HTL1 of conductivity of cm/(v·s) and a second hole transport layer HTL2 of high refractive index, thereby improving luminance and color visibility in a low gray area.

In addition, the light emitting element ED according to the embodiment may include a plurality of hole transport layers HTL1, HTL3, and HTL4 having a low refractive index and including an amine compound represented by formula 1, and a second hole transport layer HTL2 having a high refractive index, resulting in constructive interference of light inside the light emitting element ED, thereby improving external light efficiency characteristics.

Hereinafter, referring to examples and comparative examples, amine compounds according to embodiments of the inventive concept and light emitting elements of embodiments of the inventive concept will be described in detail. In addition, the examples described below are merely illustrations to aid in understanding the inventive concept, and the scope of the inventive concept is not limited thereto.

1. Manufacturing of light emitting element

(1) Manufacturing of light-emitting element of example 1

Wherein the ITO/Ag/ITO is aboutThe substrate stacked on the glass substrate with the thickness was washed with ultrapure water and washed with ultrasonic waves, and then irradiated with ultraviolet rays for about 30 minutes and treated with ozone to prepare a first electrode. Thereafter, compound 1 and compound H-1-31 were co-deposited to form +.>A thick hole injection layer.

Co-depositing compound 1 and NDP9 on the hole injection layer at a mass ratio of about 98:2 to formA thick first hole transport layer on which compound 1 and compound H-1-31 are mixed in a mass ratio of about 5:5, and then the mixture is deposited to form >A thick 4-1 th hole transport layer, depositing a compound H-1-31 on the 4-1 th hole transport layer to form +.>A thick second hole transport layer on which compound 1 and compound H-1-31 are mixed in a mass ratio of about 5:5, and then the mixture is deposited to form>A thick 4-2 th hole transport layer and depositing compound 1 on the 4-2 th hole transport layer to form +.>And forming a thick third hole transport layer, thereby forming a hole transport region. ADN and DPAVBi as blue fluorescent dopants are co-deposited on the hole transport region at a weight ratio of about 98:2 to form +.>A thick emissive layer. Then deposit Alq ₃ To form->A thick electron transport layer and LiF is deposited to form +.>A thick electron injection layer. Then, al is provided to form +.>A thick second electrode.

In the manufacturing of the light-emitting element of example 1, the hole injection layer, the hole transport layer, the emission layer, the electron transport layer, the electron injection layer, and the second electrode were formed by using a vacuum deposition apparatus.

(2) Manufacture of light-emitting element of comparative example 1

Except for depositing compounds H-1-31 to form a single unitThe light-emitting element of comparative example 1 was manufactured in the same manner as the light-emitting element of example 1 described above except for the thick hole-transporting layer.

(3) Manufacture of light-emitting elements of comparative examples 2 to 4

Light-emitting elements of comparative examples 2 to 4 were manufactured in the same manner as the light-emitting element of example 1 described above, except that the compounds C1 to C3 were used instead of the compound 1, respectively.

Compounds for manufacturing the light-emitting elements of examples and comparative examples are disclosed below. The following materials were purified by sublimation from commercial products for use in the manufacture of components.

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2. Evaluation of light-emitting element (1)

Fig. 13A, 13B, and 13C are graphs showing luminous efficiency with respect to color coordinates.

Fig. 13A shows the color coordinates and the light emission efficiency of red light in each of the light emitting element of example 1 and the light emitting element of comparative example 1. Fig. 13B shows the color coordinates and the light emission efficiency of green light in each of the light emitting element of example 1 and the light emitting element of comparative example 1. Fig. 13C shows the color coordinates and the light emission efficiency of blue light in each of the light emitting element of example 1 and the light emitting element of comparative example 1.

Referring to fig. 13A to 13C, it can be confirmed that the light emitting element of example 1 has increased light emitting efficiency of red light, green light, and blue light as compared with the light emitting element of comparative example 1.

3. Evaluation of light-emitting element (2)

Table 1 below shows the driving voltages, service lives, and efficiencies of the light emitting elements when the light emitting elements of example 1 and comparative examples 1 to 4 were driven in the low gray region. Table 1 below also shows the conductivity of the hole transport layer included in each light emitting element. In table 1, the conductivity was measured by the Transmission Line Method (TLM). The driving voltages shown in table 1 were measured using an OLED IVL measuring device. Efficiency is shown at 10mA/cm ² Is a measure of efficiency at current density. Service life (T97) means at 10mA/cm ² The time it takes for the luminance to decrease by 3% with respect to the initial luminance value at the current density of (c). In table 1, X represents that no luminance decrease occurs when the light emitting element is driven in the low gray scale region, and O represents that luminance decrease occurs when the light emitting element is driven in the low gray scale region.

TABLE 1

Referring to table 1, the light emitting element of example 1 does not have a problem of luminance reduction in a low gray scale region, but exhibits excellent efficiency as compared with the light emitting element of comparative example 1. In addition, the light emitting element of example 1 has a lower driving voltage and long service life characteristics than those of comparative examples 2 to 4.

The light emitting element of example 1 includes a light emitting element having a wavelength of about 6.0x10 ^-5 cm/(V.s) to about 10.0x10 ^-4 The hole transport layer of conductivity of cm/(v·s) thus has good driving voltage, lifetime and efficiency, and no luminance degradation occurs in the low gray scale region.

Light-emitting element of comparative example 1 including having a weight of greater than about 10.0x10 ^-4 The hole transport layer of conductivity of cm/(v·s), therefore, a decrease in luminance occurs in the low gray scale region. This may lead to defects in color visibility.

Light emission of comparative examples 2 to 4 the elements each comprise a material having a thickness of less than about 6.0x10 ^-5 The hole transport layer of conductivity of cm/(v·s), and therefore the driving voltage increases and the service life characteristics significantly decrease.

4. Evaluation of light-emitting element (3)

Fig. 14 is a histogram showing the luminance of red light (R), green light (G), and blue light (B) in each of the light emitting element of example 1 and the light emitting element of comparative example 1.

The hole transport layer included in the light emitting element of example 1 had a conductivity of about 6.37x10 ^-5 cm/(V.s), the hole transport layer included in the light-emitting element of comparative example 1 had a conductivity of about 3.30x10 ^-3 cm/(V·s)。

Referring to fig. 14, the light emitting element of example 1 exhibits brightness of about 100%, about 98%, and about 100% in red light (R), green light (G), and blue light (B), respectively. In contrast, it was confirmed that the light emitting element of comparative example 1 exhibited luminances of about 47%, about 63%, and about 98% in red light (R), green light (G), and blue light (B), respectively. Consider the light-emitting element of comparative example 1 including having a weight of greater than about 10.0x10 ^-4 A hole transport layer of conductivity of cm/(v·s), and thus the luminance decreases when the light emitting element is driven in a low gray scale region. Specifically, it is considered that in the case of the light emitting element of comparative example 1, when the first color pixel of any one of red, green, and blue is driven in the low gray region, a leakage current occurs, and thus the second color pixel adjacent to and different from the first color is driven together, the tone of the first color changes, so that gray scale breaking (gray scale breaking) occurs.

Referring to table 1, fig. 13A to 13C and fig. 14 as described above, the light emitting element of the inventive concept includes an amine compound represented by formula 1 and has a chemical structure of about 6.0x10 ^-5 cm/(V.s) to about 10.0x10 ^-4 The hole transport layer of conductivity of cm/(v·s), therefore, leakage current can be prevented from occurring during driving of the light emitting element, and luminance of red light, green light, and blue light can be improved.

In addition, the light emitting element of the embodiment may include a first hole transporting layer including a first amine compound and having a lower refractive index, a second hole transporting layer having a higher refractive index, a third hole transporting layer including a second amine compound and having a lower refractive index, and a fourth hole transporting layer including a third amine compound and having a lower refractive index, thereby exhibiting high efficiency characteristics.

The light emitting element and the display device including the same of the embodiment include a hole transporting layer having excellent conductive characteristics and a low refractive index, thereby exhibiting high efficiency and long lifetime characteristics.

Although the inventive concept has been described with reference to preferred embodiments thereof, it will be understood that the inventive concept should not be limited to those preferred embodiments, but various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the inventive concept.

Accordingly, the technical scope of the inventive concept is not intended to be limited to what is set forth in the detailed description of the specification, but rather is intended to be defined by the appended claims.

Claims

1. A light-emitting element, the light-emitting element comprising:

a first electrode;

a hole transport region disposed on the first electrode;

an emission layer disposed on the hole transport region;

an electron transport region disposed on the emission layer; and

a second electrode disposed on the electron transport region,

wherein the hole transport region comprises: a first hole transport layer disposed adjacent to the first electrode and including a first amine compound represented by the following formula 1; and a second hole transport layer provided between the first hole transport layer and the emission layer and having a refractive index larger than that of the first hole transport layer, and

The first hole transport layer has a thickness of 6.0x10 ^-5 cm/(V.sec) to 10.0x10 ^-4 The conductivity in cm/(V-sec),

[ 1]

Wherein, in the above formula 1,

R ₁ is a substituted or unsubstituted cycloalkyl group having 6 to 12 ring-forming carbon atoms,

Ar ₁ and Ar is a group ₂ Each independently is a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms,

l is a direct bond, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms, an

FR is represented by the following formula 2-1 or formula 2-2:

[ 2-1]

[ 2-2]

In the above formulas 2-1 and 2-2,

X ₁ is CR (CR) _c R _d 、NR _e O or S,

X ₂ is CR (CR) _f Or N, or a combination of two,

R _a 、R _b1 、R _b2 r is as follows _c To R _f Each independently is a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted aryl group having 2 to 3 carbon atomsHeteroaryl groups of 0 ring-forming carbon atoms, and optionally bonded to adjacent groups to form a ring,

m is an integer of 0 to 4,

n1 is an integer of 0 to 3,

n2 is an integer from 0 to 4, and

in the above formula 2-1 and formula 2-2, "-" means a position of L in the above formula 1.

2. The light-emitting element according to claim 1, wherein the first hole-transporting layer has a refractive index of 1.4 to 1.75.

3. The light-emitting element according to claim 1, wherein the second hole-transporting layer has a refractive index of 1.8 to 2.0.

4. The light-emitting element according to claim 1, further comprising a third hole-transporting layer which is provided between the second hole-transporting layer and the emission layer, and which comprises a second amine compound represented by formula 1 above.

5. The light-emitting element according to claim 4, wherein the third hole-transporting layer has a refractive index of 1.4 to 1.75.

6. The light-emitting element according to claim 4, wherein the hole-transporting region further comprises a fourth hole-transporting layer which is provided between the first hole-transporting layer and the second hole-transporting layer or between the second hole-transporting layer and the third hole-transporting layer, or between the first hole-transporting layer and the second hole-transporting layer and between the second hole-transporting layer and the third hole-transporting layer, and comprises a third amine compound represented by formula 1 above.

7. The light-emitting element according to claim 6, wherein a refractive index of the fourth hole-transporting layer is larger than the refractive index of the first hole-transporting layer and smaller than the refractive index of the second hole-transporting layer.

8. The light-emitting element according to claim 6, wherein at least one of the first to fourth hole-transporting layers further comprises a compound represented by the following formula H-1:

[ H-1]

Wherein, in the above formula H-1,

Ar _a and Ar is a group _b Each independently is a substituted or unsubstituted aryl group having from 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroaryl group having from 2 to 30 ring-forming carbon atoms,

Ar _c is a substituted or unsubstituted aryl group having from 6 to 30 ring-forming carbon atoms,

L ₁ and L ₂ Are each independently a direct bond, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms, an

p and q are each independently integers from 0 to 10.

9. The light-emitting element according to claim 1, further comprising a fourth hole-transporting layer which is provided between the first hole-transporting layer and the second hole-transporting layer or between the second hole-transporting layer and the emission layer, or between both the first hole-transporting layer and the second hole-transporting layer and the emission layer, and comprising a third amine compound represented by formula 1 above.

10. The light-emitting element according to claim 9, wherein a refractive index of the fourth hole-transporting layer is larger than the refractive index of the first hole-transporting layer and smaller than the refractive index of the second hole-transporting layer.

11. The light-emitting element according to claim 1, wherein the first hole-transporting layer is doped with 1% to 3% of a p-dopant, and

the p-dopant includes at least one of a halogenated metal compound, a quinone derivative, a metal oxide, and a cyano-containing compound.

12. The light-emitting element according to claim 1, wherein the first amine compound represented by the above formula 1 is represented by any one of the following formulas 1-1 to 1-5:

[ 1-1]

[ 1-2]

[ 1-3]

[ 1-4]

[ 1-5]

Wherein, aboveIn formulae 1-1 to 1-5, R ₁ 、L、Ar ₁ And Ar is a group ₂ As defined in formula 1 above, and X ₁ 、X ₂ 、R _a 、R _b1 、R _b2 M, n1 and n2 are the same as defined in the above formulae 2-1 and 2-2.

13. The light-emitting element according to claim 1, wherein the first amine compound represented by the above formula 1 is represented by the following formula 3:

[ 3]

Wherein, in the above formula 3,

R ₁₁ and R is ₁₂ Each independently is a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, and is optionally bonded to an adjacent group to form a ring,

s1 and s2 are each independently integers from 0 to 4, and

R ₁ l and FR are the same as defined in formula 1 above.

14. The light-emitting element according to claim 1, wherein R ₁ Is a substituted or unsubstituted cyclohexyl, a substituted or unsubstituted bicycloheptyl, a substituted or unsubstituted bicyclooctyl, a substituted or unsubstituted bicyclononyl, or a substituted or unsubstituted adamantyl.

15. The light-emitting element according to claim 1, wherein R _c And R is _d Are each independently a substituted or unsubstituted methyl group, a substituted or unsubstituted heptyl group, a substituted or unsubstituted cyclohexyl group, or a substituted or unsubstituted phenyl groupOr combine with each other to form a cyclopentane or fluorene ring.

16. The light-emitting element according to claim 1, wherein R _f Is a substituted or unsubstituted aryl group having from 6 to 30 ring-forming carbon atoms.

17. The light-emitting element according to claim 1, wherein the first amine compound represented by the above formula 1 is represented by any one of compounds in the following compound group 1:

[ Compound group 1]

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