KR102631944B1 - Aromatic compound and organic electroluminescence device including the same - Google Patents

Abstract

The present invention relates to aromatic compounds and organic electroluminescent devices containing them. The aromatic compound according to an embodiment of the present invention is represented by the following formula (1).
[Formula 1]

In Formula 1, at least two of R ₁ to R ₄ are each independently a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted ring-forming aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted alkyl group having 6 to 30 carbon atoms. It is a heteroaryl group having 2 to 30 carbon atoms to form a ring, A is an electron-accepting substituent, and D is an electron-donating substituent.

Description

Aromatic compound and organic electroluminescent device containing the same {AROMATIC COMPOUND AND ORGANIC ELECTROLUMINESCENCE DEVICE INCLUDING THE SAME}

The present invention relates to aromatic compounds and organic electroluminescent devices containing them.

As an image display device, organic electroluminescence displays are being actively developed. An organic electroluminescent display device is different from a liquid crystal display device, etc., and is a so-called device that realizes display by recombining holes and electrons injected from the first electrode and the second electrode in the light-emitting layer, thereby causing the light-emitting material, which is an organic compound contained in the light-emitting layer, to emit light. It is a light-emitting display device.

The organic electroluminescent element includes, for example, a first electrode, a hole transport layer disposed on the first electrode, a light emitting layer disposed on the hole transport layer, an electron transport layer disposed on the light emitting layer, and a second electrode disposed on the electron transport layer. Organic devices composed of these materials are known. Holes are injected from the first electrode, and the injected holes move through the hole transport layer and are injected into the light emitting layer. Meanwhile, electrons are injected from the second electrode, and the injected electrons move through the electron transport layer and are injected into the light emitting layer. When holes and electrons injected into the light-emitting layer recombine, excitons are generated within the light-emitting layer. Organic electroluminescent devices emit light using light generated when the exciton falls back to the ground state. Additionally, the organic electroluminescent element is not limited to the structure described above, and various modifications are possible.

One object of the present invention is to provide an aromatic compound and an organic electroluminescent device containing the same. More specifically, an object of the present invention is to provide an aromatic compound for a thermally activated delayed fluorescent material and an organic electroluminescent device containing the same.

One embodiment of the present invention provides an aromatic compound represented by the following formula (1).

[Formula 1]

In Formula 1, R ₁ to R ₄ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms. It is a heteroaryl group having 2 to 30 ring carbon atoms, and at least two of R ₁ to R ₄ are each independently a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, and a substituted or unsubstituted ring forming carbon number of 6 to 30. The following aryl group or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, A is represented by any one of the following formulas 2-1 to 2-11,

[Formula 2-1] [Formula 2-2] [Formula 2-3]

[Formula 2-4] [Formula 2-5]

[Formula 2-6] [Formula 2-7]

[Formula 2-8] [Formula 2-9]

[Formula 2-10] [Formula 2-11]

In Formulas 2-1 to 2-11, Q ₁ to Q ₁₅ are each independently a substituted or unsubstituted alkyl group having 1 to 15 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or It is an unsubstituted heteroaryl group having 2 to 30 ring carbon atoms,

a, d, e, f, g, m, n and o are each independently an integer from 0 to 4,

b, c, h, i, j, k and l are each independently integers from 0 to 3,

In Formula 1,

D is represented by the following formula 3-1 or formula 3-2.

[Formula 3-1] [Formula 3-2]

In Formulas 3-1 and 3-2, L ₁ and L ₂ are each independently a direct linkage or a substituted or unsubstituted ring-forming arylene group having 6 to 30 carbon atoms, and R ₅ to R ₂₂ are each Independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted silyl group, a substituted or unsubstituted alkyl group with 1 to 15 carbon atoms, a substituted or unsubstituted ring-forming aryl group with 6 to 30 carbon atoms, or a substituted or an unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, The following is an aryl group or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, and Ra and Rb, Rc and Rd, and Re and Rf may be combined with each other to form a ring.

Chemical Formula 1 may be represented by any one of the following Chemical Formulas 1-1 to 1-4.

[Formula 1-1] [Formula 1-2]

[Formula 1-3] [Formula 1-4]

In Formulas 1-1 to 1-4, R ₁ to R ₄ are each independently a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or It is an unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, and A and D are the same as described above.

At least two of R ₁ to R ₄ may each independently be a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms or a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms.

At least two of R ₁ to R ₄ may each independently be a methyl group or a phenyl group.

D is represented by Formula 3-2, X is CRaRb, and Ra and Rb may be the same as described above.

D may be represented by any one of the following formulas 3-2-1 to 3-2-5.

[Formula 3-2-1] [Formula 3-2-2]

[Formula 3-2-3] [Formula 3-2-4]

[Formula 3-2-5]

In Formulas 3-2-1 to 3-2-5, L ₂ , R ₁₅ to R ₁₇ and R ₂₀ to R ₂₂ are the same as described above.

L ₁ and L ₂ may each independently be a direct bond.

One embodiment of the present invention includes a first electrode, a hole transport region provided on the first electrode, a light-emitting layer provided on the hole transport region, an electron transport region provided on the light-emitting layer, and a second electrode provided on the electron transport region, An organic electroluminescent device is provided in which at least one of the hole transport region, the light emitting layer, and the electron transport region includes an aromatic compound according to an embodiment of the present invention described above. The first electrode and the second electrode are each independently selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF/Ca, LiF/Al, Mo, It includes at least one selected from Ti, In, Sn, and Zn, two or more compounds selected from these, a mixture of two or more selected from these, or oxides thereof.

The aromatic compound represented by Formula 1 may be included in the light-emitting layer.

The aromatic compound represented by Formula 1 may have an absolute value of the difference between the singlet energy level and the triplet energy level of 0.2 eV or less.

The aromatic compound represented by Formula 1 may be a material for thermally activated delayed fluorescence.

The compound according to an embodiment of the present invention can be used as a material for an organic electroluminescent device.

The compound according to an embodiment of the present invention can be used as a material for delayed fluorescence.

An organic electroluminescent device according to an embodiment of the present invention containing a compound according to an embodiment of the present invention can improve efficiency and reduce roll-off and simultaneously emit blue light.

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

The above objects, other objects, features and advantages of the present invention will be easily understood through the accompanying drawings and the following preferred embodiments. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content will be thorough and complete and so that the spirit of the present invention can be sufficiently conveyed to those skilled in the art.

While describing each drawing, similar reference numerals are used for similar components. In the attached drawings, the dimensions of the structures are enlarged from the actual size for clarity of the present invention. Terms such as first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, a first component may be named a second component, and similarly, the second component may also be named a first component without departing from the scope of the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

In this specification, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof. Additionally, when a part of a layer, membrane, region, plate, etc. is said to be “on” another part, this includes not only being “directly above” the other part, but also cases where there is another part in between. Conversely, when a part of a layer, membrane, region, plate, etc. is said to be "underneath" another part, this includes not only being "immediately below" the other part, but also cases where there is another part in between.

In this specification, means the connected part.

As used herein, “substituted or unsubstituted” refers to a deuterium atom, halogen group, cyano group, nitro group, amino group, silyl group, boron group, aryl amine group, phosphine oxide group, phosphine sulfide group, alkyl group, alkenyl group. , may mean substituted or unsubstituted with one or more substituents selected from the group consisting of an aryl group and a heterocyclic group. Additionally, each of the above-exemplified substituents may be substituted or unsubstituted. For example, a biphenyl group may be interpreted as an aryl group, or as a phenyl group substituted with a phenyl group.

As used herein, “joining together to form a ring” may mean combining with each other to form a substituted or unsubstituted hydrocarbon ring, or a substituted or unsubstituted hetero ring. Hydrocarbon rings include aliphatic hydrocarbon rings and aromatic hydrocarbon rings. Heterocycles include aliphatic heterocycles and aromatic heterocycles. Hydrocarbon rings and heterocycles may be monocyclic or polycyclic. Additionally, rings formed by combining with each other may be connected to other rings to form a spiro structure.

In this specification, examples of halogen groups include fluorine atom, chlorine atom, bromine atom, or iodine atom.

As used herein, alkyl groups may be straight chain, branched chain, or cyclic. The carbon number of the alkyl group is 1 to 30, 1 to 20, 1 to 15, 1 to 10, or 1 to 6. Examples of alkyl groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, t-butyl group, i-butyl group, 2-ethylbutyl group, and 3, 3-dimethylbutyl group. , n-pentyl group, i-pentyl group, neopentyl group, t-pentyl group, cyclopentyl group, 1-methylpentyl group, 3-methylpentyl group, 2-ethylpentyl group, 4-methyl-2-pentyl group. , n-hexyl group, 1-methylhexyl group, 2-ethylhexyl group, 2-butylhexyl group, cyclohexyl group, 4-methylcyclohexyl group, 4-t-butylcyclohexyl group, n-heptyl group, 1 -Methylheptyl group, 2,2-dimethylheptyl group, 2-ethylheptyl group, 2-butylheptyl group, n-octyl group, t-octyl group, 2-ethyloctyl group, 2-butyloctyl group, 2-hexyl group Siloctyl group, 3,7-dimethyloctyl group, cyclooctyl group, n-nonyl group, n-decyl group, adamantyl group, 2-ethyldecyl group, 2-butyldecyl group, 2-hexyldecyl group, 2-octyl group Tyldecyl group, n-undecyl group, n-dodecyl group, 2-ethyldodecyl group, 2-butyldodecyl group, 2-hexyldodecyl group, 2-octyldodecyl group, n-tridecyl group, n-tetradecyl group, n -Pentadecyl group, n-hexadecyl group, 2-ethylhexadecyl group, 2-butylhexadecyl group, 2-hexylhexadecyl group, 2-octylhexadecyl group, n-heptadecyl group, n-octadecyl group , n-nonadecyl group, n-icosyl group, 2-ethyl icosyl group, 2-butyl icosyl group, 2-hexyl icosyl group, 2-octyl icosyl group, n-henicosyl group, n-docosyl group, n-tricosyl group Examples include syl group, n-tetracosyl group, n-pentacosyl group, n-hexacosyl group, n-heptacosyl group, n-octacosyl group, n-nonacosyl group, and n-triacontyl group, It is not limited to these.

As used herein, an aryl group refers to 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 ring-forming carbon number of the aryl group may be 6 to 30, 6 to 20, or 6 to 15. Examples of aryl groups include phenyl group, naphthyl group, fluorenyl group, anthracenyl group, phenanthryl group, biphenyl group, terphenyl group, quaternophenyl group, quincphenyl group, sexiphenyl group, triphenylene group, pyrenyl group, benzofluoranthenyl group, Examples include chrysenyl group, but it is not limited to these.

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

In the present specification, the heteroaryl group may be a heteroaryl group containing one or more of O, N, P, Si, Ge, and S as heterogeneous elements. The number of ring carbon atoms in the heteroaryl group is 2 to 30 or 2 to 20. Examples of heteroaryl groups include thiophene group, furan group, pyrrole group, imidazole group, thiazole group, oxazole group, oxadiazole group, triazole group, pyridyl group, bipyridyl group, pyrimidyl group, triazine group, triazole group, Acridyl group, pyridazine group, pyrazinyl group, quinolinyl group, quinazoline group, quinoxalinyl group, phenoxazyl group, phthalazinyl group, pyrido pyrimidinyl group, pyrido pyrazinyl group, pyrazino pyrazinyl group , isoquinoline group, indole group, carbazole group, N-arylcarbazole group, N-heteroarylcarbazole group, N-alkylcarbazole group, benzoxazole group, benzoimidazole group, benzothiazole group, benzocarbazole group, benzothiophene group, dibenzothiophene group, thienothiophene group, benzofuranyl group, phenanthroline group, thiazolyl group, isoxazolyl group, oxadiazolyl group, thiadiazolyl group, benzothiazolyl group, phenothiazinyl group, and Dibenzofuranyl group, etc., but is not limited to these.

In this specification, the description regarding the aryl group described above can be applied, except that the arylene group is a divalent group.

In this specification, silyl groups include alkyl silyl groups and aryl silyl groups. Examples of silyl groups include trimethylsilyl group, triethylsilyl group, t-butyldimethylsilyl group, vinyldimethylsilyl group, propyldimethylsilyl group, triphenylsilyl group, diphenylsilyl group, and phenylsilyl group. It is not limited.

As used herein, boron groups include alkyl boron groups and aryl boron groups. Examples of boron groups include, but are not limited to, trimethyl boron group, triethyl boron group, t-butyldimethyl boron group, triphenyl boron group, diphenyl boron group, and phenyl boron group.

In this specification, alkenyl groups may be straight chain or branched. The number of carbon atoms is not particularly limited, but is 2 to 30, 2 to 30, or 2 to 10. Examples of alkenyl groups include, but are not limited to, vinyl, 1-butenyl, 1-pentenyl, 1,3-butadienyl aryl, styrenyl, and styrylvinyl groups.

In this specification, the number of carbon atoms of 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 amine groups include, but are not limited to, methylamine group, dimethylamine group, phenylamine group, diphenylamine group, naphthylamine group, 9-methyl-anthracenylamine group, and triphenylamine group.

Hereinafter, an aromatic compound according to an embodiment of the present invention will be described.

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

[Formula 1]

In Formula 1, R ₁ to R ₄ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms. It is a heteroaryl group having 2 to 30 ring carbon atoms.

In Formula 1, at least two of R ₁ to R ₄ are each independently a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted ring-forming aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted alkyl group having 6 to 30 carbon atoms. It is a heteroaryl group with 2 to 30 carbon atoms to form a ring. That is, in Formula 1, at least two of R ₁ to R ₄ are substituted with a substituent other than a hydrogen atom.

In Formula 1, A is represented by any one of the following Formulas 2-1 to 2-11.

[Formula 2-1] [Formula 2-2] [Formula 2-3]

[Formula 2-4] [Formula 2-5]

[Formula 2-6] [Formula 2-7]

[Formula 2-8] [Formula 2-9]

[Formula 2-10] [Formula 2-11]

In Formulas 2-1 to 2-11, Q ₁ to Q ₁₅ are each independently a substituted or unsubstituted alkyl group having 1 to 15 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or It is an unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, and a, d, e, f, g, m, n, and o are each independently integers of 0 to 4, and b, c, h, i, j, k and l are each independently integers from 0 to 3.

In Formula 2-1, when a is 2 or more, a plurality of Q1s are the same or different from each other.

In Formula 2-2, when b is 2 or more, a plurality of Q2s are the same or different from each other.

In Formula 2-3, when c is 2 or more, a plurality of Q3s are the same or different from each other.

In Formula 2-4, when d is 2 or more, the plurality of Q4s are the same as or different from each other, and when e is 2 or more, the plurality of Q5s are the same or different from each other.

In Formula 2-5, when f is 2 or more, the plurality of Q6s are the same or different from each other, and when g is 2 or more, the plurality of Q7s are the same or different from each other.

In Formula 2-6, when h is 2 or more, a plurality of Q8s are the same or different from each other.

In Formula 2-7, when i is 2 or more, a plurality of Q9s are the same or different from each other.

In Formula 2-8, when j is 2 or more, a plurality of Q10 are the same or different from each other.

In Formula 2-9, when k is 2 or more, a plurality of Q11 are the same or different from each other.

In Formula 2-10, when l is 2 or more, the plurality of Q12s are the same or different from each other, and when m is 2 or more, the plurality of Q13s are the same or different from each other.

In Formula 2-11, when n is 2 or more, the plurality of Q14s are the same or different from each other, and when o is 2 or more, the plurality of Q15s are the same or different from each other.

In Formula 2-1, a may be 0.

In Formula 2-1, a is an integer of 1 to 4, and Q1 may each independently be a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms.

In Formula 2-2, b may be 0. However, it is not limited thereto, and in Formula 2-2, b may be an integer between 1 and 3.

In Formula 2-3, c may be 0.

In Formula 2-3, c is an integer of 1 to 3, and Q3 may each independently be a substituted or unsubstituted alkyl group with 1 to 15 carbon atoms or a substituted or unsubstituted aryl group with 6 to 30 ring carbon atoms. there is.

In Formula 2-4, d+e=0.

In Formula 2-4, at least one of d and e is an integer of 1 to 4, and at least one of Q4 and Q5 may be a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms.

In Formula 2-5, f+g=0.

In Formula 2-5, at least one of f and g is an integer of 1 to 4, and at least one of Q6 and Q7 may be a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms.

In Formula 2-6, h may be 0.

In Formula 2-6, h is an integer of 1 to 3, and Q8 is each independently a substituted or unsubstituted alkyl group with 1 to 15 carbon atoms or a substituted or unsubstituted aryl group with 6 to 30 ring carbon atoms. You can.

In Formula 2-7, i may be 0. However, it is not limited thereto, and in Formula 2-7, i may be an integer between 1 and 3.

In Formula 2-8, j may be 0.

In Formula 2-8, j is an integer of 1 to 3, and Q10 is each independently a substituted or unsubstituted alkyl group with 1 to 15 carbon atoms or a substituted or unsubstituted aryl group with 6 to 30 ring carbon atoms. You can.

In Formula 2-9, k may be 0.

In Formula 2-9, k is an integer of 1 to 3, and Q11 is each independently a substituted or unsubstituted alkyl group with 1 to 15 carbon atoms or a substituted or unsubstituted aryl group with 6 to 30 ring carbon atoms. You can.

In Formula 2-10, l+m=0.

In Formula 2-10, at least one of l and m is an integer of 1 or more, and at least one of Q12 and Q13 is each independently a substituted or unsubstituted alkyl group having 1 to 15 carbon atoms or a substituted or unsubstituted ring-forming alkyl group having 6 carbon atoms. It may be an aryl group of more than 30 or less.

In Formula 2-11, n+o=0.

In Formula 2-11, at least one of n and o is an integer of 1 to 4, and at least one of Q14 and Q15 is each independently a substituted or unsubstituted alkyl group having 1 to 15 carbon atoms or a substituted or unsubstituted ring. It may be an aryl group having 6 to 30 carbon atoms.

In Formula 1, D is represented by Formula 3-1 or Formula 3-2 below.

[Formula 3-1] [Formula 3-2]

In Formulas 3-1 and 3-2, L ₁ and L ₂ are each independently a direct linkage or a substituted or unsubstituted arylene group having 6 to 30 ring carbon atoms.

As used herein, “direct linkage” may include a single bond.

In Formulas 3-1 and 3-2, R ₅ to R ₂₂ are each independently a hydrogen atom, a deuterium atom, a halogen group, a substituted or unsubstituted silyl group, a substituted or unsubstituted alkyl group having 1 to 15 carbon atoms, or a substituted Or an unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms.

In Formula 3-2, It is a heteroaryl group having 2 to 30 carbon atoms.

In Formula 3-2, when X is CRaRb, Ra and Rb may combine with each other to form a ring.

In Formula 3-2, when X is SiRcRd, Rc and Rd may be combined with each other to form a ring.

In Formula 3-2, when X is GeReRf, Re and Rf may combine with each other to form a ring.

The aromatic compound according to one embodiment of the present invention includes an electron acceptor, an electron donor, and a linker. Specifically, the substituted phenylene group represented by Formula 1 is the linker, A in Formula 1 is the electron acceptor, and D is the electron donor.

The aromatic compound according to one embodiment of the present invention includes at least a disubstituted bulky linker. “At least disubstituted” means that the phenylene group is substituted by two or more in addition to the electron acceptor represented by A and the electron donor represented by D.

For example, Chemical Formula 1 may be represented by any one of the following Chemical Formulas 1-1 to 1-4.

[Formula 1-1] [Formula 1-2]

[Formula 1-3] [Formula 1-4]

In Formulas 1-1 to 1-4, R ₁ to R ₄ are each independently a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or It is an unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, and A and D are the same as described above. That is, in Formulas 1-1 to 1-4, R ₁ to R ₄ are each independently substituted with a substituent other than a hydrogen atom.

The aromatic compounds represented by Formula 1-1, 1-2 or 1-3 are linked through a linker in which the electron acceptor represented by A and the electron donor represented by D are disubstituted phenylene groups.

The aromatic compound represented by Formula 1-4 is linked through a linker in which the electron acceptor represented by A and the electron donor represented by D are tetrasubstituted phenylene groups. The aromatic compound represented by Formula 1-4 contains a linker that has a greater steric effect than the aromatic compound represented by Formula 1-1, 1-2, or 1-3, and thus has the advantage of realizing high efficiency.

However, it is not limited thereto, and the aromatic compound represented by Formula 1 may be connected through a linker in which the electron acceptor represented by A and the electron donor represented by D are trisubstituted phenylene groups.

In Formula 1, at least two of R ₁ to R ₄ may each independently be a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms or a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms.

In Formula 1, at least two of R ₁ to R ₄ may each independently be a methyl group or a phenyl group.

Chemical Formula 1 may be represented by any of the following structural formulas.

In the above structural formulas, Ph refers to a phenyl group.

In Formula 1, D may be represented by Formula 3-2, and X in Formula 3-2 may be CRaRb. The definitions of Ra and Rb are the same as described above.

In Formula 1, D may be represented by the following Formula 3-2-1.

[Formula 3-2-1]

However, it is not limited thereto, and for example, in Formula 1, D may be represented by any one of the following Formulas 3-2-2 to 3-2-5.

[Formula 3-2-2] [Formula 3-2-3]

[Formula 3-2-4] [Formula 3-2-5]

In Formulas 3-2-1 to 3-2-5, L ₂ , R ₁₅ to R ₁₇ and R ₂₀ to R ₂₂ are the same as defined in claim 1.

In Formula 3-2-1, L ₂ may be a direct bond, and R ₁₅ to R ₁₇ and R ₂₀ to R ₂₂ may be hydrogen atoms. In Formula 3-2-1, L ₂ is a direct bond, R ₁₇ and R ₂₀ are substituted or unsubstituted alkyl groups having 1 to 30 carbon atoms, and R ₁₅ , R ₁₆ , R ₂₁ and R ₂₂ are hydrogen atoms. It may be. In Formula 3-2-1, L ₂ is a direct bond, R ₁₇ and R ₂₀ are methyl groups, and R ₁₅ , R ₁₆ , R ₂₁ and R ₂₂ may be hydrogen atoms.

In Formulas 3-2-2 to 3-2-5, L ₂ may be a direct bond, and R ₁₅ to R ₁₇ and R ₂₀ to R ₂₂ may be hydrogen atoms. In Formulas 3-2-2 to 3-2-5, L ₂ is a direct bond, R ₁₇ and R ₂₀ are substituted or unsubstituted alkyl groups having 1 to 30 carbon atoms, R ₁₅ , R ₁₆ , R ₂₁ and R ₂₂ may be a hydrogen atom. In Formulas 3-2-2 to 3-2-5, L ₂ may be a direct bond, R ₁₇ and R ₂₀ may be a methyl group, and R ₁₅ , R ₁₆ , R ₂₁ and R ₂₂ may be a hydrogen atom.

In Formulas 3-1 and 3-2, L ₁ and L ₂ may each independently be a direct bond or a phenylene group.

In Formulas 3-1 and 3-2, L ₁ and L ₂ may each independently be a direct bond.

The aromatic compound represented by Formula 1 may be at least one selected from compounds shown in compound group 1 below. Among the compounds below, Ph refers to a phenyl group.

[Compound Group 1]

.

The aromatic compound according to an embodiment of the present invention can be used as a material for thermally activated delayed fluorescence. The aromatic compound according to an embodiment of the present invention may emit blue light through thermally activated delayed fluorescence. The aromatic compound according to an embodiment of the present invention can achieve highly efficient blue light emission.

The aromatic compound according to an embodiment of the present invention can implement a roll-off reduction effect by short-delayed fluorescence lifetime by introducing a linker with high steric hindrance (large volume).

Hereinafter, an organic electroluminescent device according to an embodiment of the present invention will be described. Hereinafter, the differences from the aromatic compound according to an embodiment of the present invention described above will be described in detail, and parts not described will be in accordance with the aromatic compound according to an embodiment of the present invention described above.

An organic electroluminescent device according to an embodiment of the present invention includes the aromatic compound according to an embodiment of the present invention described above.

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

1 and 2, the organic electroluminescent device 10 according to an embodiment of the present invention includes a first electrode (EL1), a hole transport region (HTR), an emitting layer (EML), and an electron transport region (ETR). and a second electrode (EL2).

The first electrode EL1 has conductivity. The first electrode EL1 may be a pixel electrode or an anode. The first electrode EL1 may be a transmissive electrode, a semi-transmissive electrode, or a reflective electrode. When the first electrode EL1 is a transparent electrode, the first electrode EL1 is made of a transparent metal oxide, for example, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), or indium ITZO. tin zinc oxide), etc. When the first electrode EL1 is a transflective electrode or a reflective electrode, the first electrode EL1 is made of Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, It may include LiF/Ca, LiF/Al, Mo, Ti, or a compound or mixture thereof (for example, a mixture of Ag and Mg). Or a plurality of layer structure including a reflective film or semi-transmissive film formed of the above materials and a transparent conductive film formed of ITO (indium tin oxide), IZO (indium zinc oxide), ZnO (zinc oxide), ITZO (indium tin zinc oxide), etc. It can be.

The hole transport region HTR is provided on the first electrode EL1. The hole transport region (HTR) may include at least one of a hole injection layer (HIL), a hole transport layer (HTL), a hole buffer layer, and an electron blocking layer. The thickness of the hole transport region (HTR) may be, for example, about 200Å to about 3000Å.

The hole transport region (HTR) may have a single layer made of a single material, a single layer made of a plurality of different materials, or a multilayer structure having a plurality of layers made of a plurality of different materials.

For example, the hole transport region (HTR) may have a single-layer structure of a hole injection layer (HIL) or a hole transport layer (HTL), or may have a single-layer structure composed of a hole injection material and a hole transport material. In addition, the hole transport region (HTR) has a single-layer structure made of a plurality of different materials, or a hole injection layer (HIL)/hole transport layer (HTL) sequentially stacked from the first electrode EL1, or a hole injection layer. layer (HIL)/hole transport layer (HTL)/hole buffer layer, hole injection layer (HIL)/hole buffer layer, hole transport layer (HTL)/hole buffer layer or hole injection layer (HIL)/hole transport layer (HTL)/electron blocking layer. It may have a structure, but is not limited to this.

The hole transport region (HTR) is created using various methods such as vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB), inkjet printing, laser printing, and laser induced thermal imaging (LITI). It can be formed using

The hole injection layer (HIL) includes, for example, phthalocyanine compounds such as copper phthalocyanine; DNTPD(N,N'-diphenyl-N,N'-bis-[4-(phenyl-m-tolyl-amino)-phenyl]-biphenyl-4,4'-diamine), m-MTDATA(4,4' ,4"-tris(3-methylphenylphenylamino)triphenylamine), TDATA(4,4'4"-Tris(N,N-diphenylamino)triphenylamine), 2-TNATA(4,4',4"-tris{N,- (2-naphthyl)-N-phenylamino}-triphenylamine), PEDOT/PSS(Poly(3,4-ethylenedioxythiophene)/Poly(4-styrenesulfonate)), PANI/DBSA(Polyaniline/Dodecylbenzenesulfonic acid), PANI/CSA(Polyaniline) /Camphor sulfonicacid), PANI/PSS((Polyaniline)/Poly(4-styrenesulfonate)), NPB(N,N'-di(naphthalene-l-yl)-N,N'-diplienyl-benzidine), triphenylamine Containing polyether ketone (TPAPEK), 4-Isopropyl-4'-methyldiphenyliodonium Tetrakis(pentafluorophenyl)borate], HAT-CN(dipyrazino[2,3-f: 2',3'-h] quinoxaline-2,3 ,6,7,10,11-hexacarbonitrile), etc.

The hole transport layer (HTL) is, for example, carbazole-based derivatives such as N-phenylcarbazole and polyvinylcarbazole, fluorine-based derivatives, TPD (N,N'-bis(3-methylphenyl)-N, Triphenylamine derivatives such as N'-diphenyl-[1,1-biphenyl]-4,4'-diamine), TCTA (4,4',4"-tris(N-carbazolyl)triphenylamine), NPB(N ,N'-di(naphthalene-l-yl)-N,N'-diplienyl-benzidine), TAPC(4,4'-Cyclohexylidene bis[N,N-bis(4-methylphenyl)benzenamine]), HMTPD(4 ,4'-Bis[N,N'-(3-tolyl)amino]-3,3'-dimethylbiphenyl), etc.

The thickness of the hole transport region (HTR) may be about 100 Å to about 10000 Å, for example, about 100 Å to about 1000 Å. When the hole transport region (HTR) includes both a hole injection layer (HIL) and a hole transport layer (HTL), the thickness of the hole injection layer (HIL) is about 100 Å to about 10000 Å, for example, about 100 Å to about 1000 Å, The thickness of the hole transport layer (HTL) may be about 30Å to about 1000Å. When the thickness of the hole transport region (HTR), hole injection layer (HIL), and hole transport layer (HTL) satisfies the above-described range, satisfactory hole transport characteristics can be obtained without a substantial increase in driving voltage.

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

As described above, the hole transport region (HTR) may further include at least one of a hole buffer layer and an electron blocking layer in addition to the hole injection layer (HIL) and the hole transport layer (HTL). The hole buffer layer can increase light emission efficiency by compensating for the resonance distance according to the wavelength of light emitted from the light emitting layer (EML). The material included in the hole buffer layer may be a material that can be included in the hole transport region (HTR). The electron blocking layer is a layer that serves to prevent electron injection from the electron transport region (ETR) to the hole transport region (HTR).

The light emitting layer (EML) is provided on the hole transport region (HTR). For example, the thickness of the light emitting layer (EML) may be about 100Å to about 1000Å. The light emitting layer (EML) may have a single layer made of a single material, a single layer made of a plurality of different materials, or a multi-layer structure having a plurality of layers made of a plurality of different materials.

The aromatic compound according to an embodiment of the present invention described above is included in at least one of the hole transport region (HTR), the emitting layer (EML), and the electron transport region (ETR).

Hereinafter, the inclusion of the aromatic compound according to an embodiment of the present invention described above in the light emitting layer (EML) will be described as an example. However, it is not limited thereto, and the aromatic compound according to an embodiment of the present invention may be included in at least one layer among one or more organic layers provided between the first electrode EL1 and the second electrode EL2. For example, the aromatic compound according to an embodiment of the present invention may be included in the hole transport region (HTR). For example, the aromatic compound according to an embodiment of the present invention may be included in the hole transport layer (HTL).

The emitting layer (EML) may include an aromatic compound according to an embodiment of the present invention described above. Specifically, the light emitting layer (EML) may include an aromatic compound represented by the following formula (1).

[Formula 1]

Detailed descriptions of R ₁ to R ₄ , A and D will be omitted as they are the same as described above.

The light emitting layer (EML) may include one or two or more types of aromatic compounds represented by Chemical Formula 1. The light emitting layer (EML) may further include known materials other than the aromatic compound represented by Chemical Formula 1. For example, spiro-DPVBi (spiro-DPVBi), spiro-6P (spiro-6P, 2,2',7,7'-tetrakis(biphenyl-4-yl)-9,9'-spirobifluorene (spiro-sexiphenyl )), DSB (distyryl-benzene), DSA (distyryl-arylene), PFO (polyfluorene) polymer, and PPV (poly(p-phenylene vinylene)) polymer. It can be done, but it is not limited thereto.

The aromatic compound according to an embodiment of the present invention may be included in the light emitting layer (EML) and emit delayed fluorescence. The aromatic compound represented by Formula 1 may be a material for delayed fluorescence. The aromatic compound represented by Formula 1 may be a material for thermally activated delayed fluorescence (TADF).

The aromatic compound according to an embodiment of the present invention may be a material for thermally activated delayed fluorescence that emits blue light. The aromatic compound according to an embodiment of the present invention may emit blue light having a wavelength range of less than about 470 nm, for example, emitting blue light having a wavelength range of about 440 nm to about 470 nm or about 450 nm to about 470 nm. It may be.

The aromatic compound according to an embodiment of the present invention may have an absolute value of the difference between the singlet energy level and the triplet energy level of 0.2 eV or less. There is an advantage in that thermally activated delayed fluorescence can be efficiently emitted by adjusting the singlet-triplet energy gap to be small.

The light emitting layer (EML) may further include a host. The host is not particularly limited as long as it is a commonly used material, for example, Alq ₃ (tris(8-hydroxyquinolino)aluminum), CBP(4,4'-bis(N-carbazolyl)-1,1'-biphenyl) , PVK(poly(n-vinylcabazole), ADN(9,10-di(naphthalene-2-yl)anthracene), TCTA(4,4',4''-Tris(carbazol-9-yl)-triphenylamine), TPBi(1,3,5-tris(N-phenylbenzimidazole-2-yl)benzene), TBADN(3-tert-butyl-9,10-di(naphth-2-yl)anthracene), DSA(distyrylarylene), CDBP (4,4'-bis(9-carbazolyl)-2,2''-dimethyl-biphenyl), MADN(2-Methyl-9,10-bis(naphthalen-2-yl)anthracene), DPEPO ( bis[2 -(diphenylphosphino)phenyl]ether oxide), CP1 (Hexaphenyl cyclotriphosphazene), UGH2 (1,4-Bis(triphenylsilyl)benzene), DPSiO ₃ (Hexaphenylcyclotrisiloxane), DPSiO ₄ (Octaphenylcyclotetra siloxane), PPF(2,8-Bis( diphenylphosphoryl)dibenzofuran), etc. may be used.

For example, the light emitting layer (EML) may have a thickness of about 100Å to about 1000Å.

An electron transport region (ETR) is provided on the light emitting layer (EML). The electron transport region (ETR) may include at least one of an electron blocking layer, an electron transport layer (ETL), and an electron injection layer (EIL), but is not limited thereto.

The electron transport region (ETR) may have a single layer made of a single material, a single layer made of a plurality of different materials, or a multilayer structure having a plurality of layers made of a plurality of different materials.

For example, the electron transport region (ETR) may have a single-layer structure of an electron injection layer (EIL) or an electron transport layer (ETL), or may have a single-layer structure composed of an electron injection material and an electron transport material. In addition, the electron transport region (ETR) has a single-layer structure made of a plurality of different materials, or an electron transport layer (ETL)/electron injection layer (EIL), or a hole blocking layer sequentially stacked from the first electrode (AN). It may have a layer/electron transport layer (ETL)/electron injection layer (EIL) structure, but is not limited thereto. The thickness of the electron transport region (ETR) may be, for example, about 1000Å to about 1500Å.

The electron transport region (ETR) is created using various methods such as vacuum deposition, spin coating, cast, LB (Langmuir-Blodgett), inkjet printing, laser printing, and laser induced thermal imaging (LITI). It can be formed using

When the electron transport region (ETR) includes an electron transport layer (ETL), the electron transport region (ETR) is Alq ₃ (Tris(8-hydroxyquinolinato)aluminum), 1,3,5-tri[(3-pyridyl)- phen-3-yl]benzene, 2,4,6-tris(3'-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine, 2-(4-(N-phenylbenzoimidazolyl -1-ylphenyl)-9,10-dinaphthylanthracene, TPBi(1,3,5-Tri(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl), BCP(2,9-Dimethyl-4 ,7-diphenyl-1,10-phenanthroline), Bphen(4,7-Diphenyl-1,10-phenanthroline), TAZ(3-(4-Biphenylyl)-4-phenyl-5-tert-butylphenyl-1,2 ,4-triazole), NTAZ(4-(Naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole), tBu-PBD(2-(4-Biphenylyl)-5-( 4-tert-butylphenyl)-1,3,4-oxadiazole), BAlq(Bis(2-methyl-8-quinolinolato-N1,O8)-(1,1'-Biphenyl-4-olato)aluminum), Bebq ₂ (May include, but are not limited to, berylliumbis (benzoquinolin-10-olate), ADN (9,10-di(naphthalene-2-yl)anthracene), and mixtures thereof. The thickness of the electron transport layers (ETL) is It may be about 100 Å to about 10000 Å, for example, about 1000 Å to about 1500 Å. When the thickness of the electron transport layers (ETL) satisfies the above-described range, satisfactory electron transport characteristics can be obtained without a substantial increase in driving voltage. there is.

When the electron transport region (ETR) includes an electron injection layer (EIL), the electron transport region (ETR) is a lanthanide metal such as LiF, LiQ (Lithium quinolate), Li ₂ O, BaO, NaCl, CsF, Yb, Alternatively, halogenated metals such as RbCl and RbI may be used, but are not limited thereto. The electron injection layer (EIL) may also be made of a mixture of an electron transport material and an insulating organo metal salt. Organic metal salts can be materials with an energy band gap of approximately 4 eV or more. Specifically, for example, the organometallic salt may include metal acetate, metal benzoate, metal acetoacetate, metal acetylacetonate, or metal stearate. You can. The thickness of the electron injection layers (EIL) may be about 1Å to about 100Å, or about 3Å to about 90Å. When the thickness of the electron injection layers (EIL) satisfies the range described above, satisfactory electron injection characteristics can be obtained without a substantial increase in driving voltage.

The electron transport region (ETR) may include a hole blocking layer, as previously mentioned. The hole blocking layer may include, for example, at least one of BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) and Bphen (4,7-diphenyl-1,10-phenanthroline). However, it is not limited to this.

The second electrode EL2 is provided on the electron transport region ETR. The second electrode EL2 may be a common electrode or a cathode. The second electrode EL2 may be a transmissive electrode, a semi-transmissive electrode, or a reflective electrode. When the second electrode EL2 is a transparent electrode, the second electrode EL2 is made of a transparent metal oxide, for example, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), or indium ITZO. It may be made of tin zinc oxide, etc.

When the second electrode EL2 is a transflective electrode or a reflective electrode, the second electrode EL2 is made of Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, It may include LiF/Ca, LiF/Al, Mo, Ti, or a compound or mixture containing these (for example, a mixture of Ag and Mg). Or a plurality of layer structure including a reflective film or semi-transmissive film formed of the above materials and a transparent conductive film formed of ITO (indium tin oxide), IZO (indium zinc oxide), ZnO (zinc oxide), ITZO (indium tin zinc oxide), etc. It can be.

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

In the organic electroluminescent device 10, as voltage is applied to the first electrode EL1 and the second electrode EL2, holes injected from the first electrode EL1 form the hole transport region HTR. The electrons injected from the second electrode EL2 move to the light emitting layer (EML) through the electron transport region (ETR). Electrons and holes recombine in the light emitting layer (EML) to generate excitons, and the excitons emit light as they fall from the excited state to the ground state.

When the organic electroluminescent device 10 is a top-emission type, the first electrode EL1 may be a reflective electrode, and the second electrode EL2 may be a transmissive electrode or a semi-transmissive electrode. When the organic electroluminescent device 10 is a bottom-emitting type, the first electrode EL1 may be a transmissive electrode or a semi-transmissive electrode, and the second electrode EL2 may be a reflective electrode.

An organic electroluminescent device according to an embodiment of the present invention is characterized by including an aromatic compound represented by Chemical Formula 1. The aromatic compound represented by Formula 1 contains a bulky linker. By including a compound into which a linker with a large steric effect is introduced, the organic electroluminescent device according to an embodiment of the present invention has the effect of improving efficiency and reducing roll-off while simultaneously realizing blue light emission.

Hereinafter, the present invention will be described in more detail through specific examples and comparative examples. The following examples are merely examples to aid understanding of the present invention, and the scope of the present invention is not limited thereto.

(Synthesis example)

The aromatic compound according to an embodiment of the present invention can be synthesized, for example, as follows. However, the method for synthesizing aromatic compounds according to an embodiment of the present invention is not limited to this.

1. Synthesis of compound 127

Compound 55, an aromatic compound according to an embodiment of the present invention, can be synthesized, for example, by the following reaction.

Under an argon (Ar) atmosphere, 1.00 g of Compound A, 3.50 g of Compound B, and 0.96 g of Pd(PPh ₃ ) ₄ and 1.78 g of K ₃ PO ₄ were added to a 100 mL three-necked flask, and the mixture was heated and refluxed in 50 mL of toluene solvent for 8 hours. . After air cooling, water was added to separate the organic layer, and the solvent was distilled. The obtained crude product was purified by silica gel column chromatography (using a mixed solvent of dichloromethane and hexane) and then recrystallized with a mixed solvent of toluene/hexane to obtain 2.50 g (yield) of the compound as a white solid. 69%) obtained.

The molecular weight of the compound measured by FAB-MS measurement was 870. Through the above results, it was confirmed that the white solid compound was compound 127.

2. Synthesis of compound 123

Under an argon (Ar) atmosphere, 1.80 g of Compound A, 3.27 g of Compound C, and 1.74 g of Pd(PPh ₃ ) ₄ and 3.20 g of K ₃ PO ₄ were added to a 100 mL three-necked flask, and the mixture was heated and refluxed in 50 mL of toluene solvent for 6 hours. . After air cooling, water was added to separate the organic layer, and the solvent was distilled. The obtained crude product was purified by silica gel column chromatography (using a mixed solvent of dichloromethane and hexane) and then recrystallized with a mixed solvent of toluene/hexane to obtain 3.8 g (yield) of the compound as a white solid. 85%) was obtained.

The molecular weight of the compound measured by FAB-MS measurement was 593. Through the above results, it was confirmed that the white solid compound was compound 123.

3. Synthesis of compound 124

Under an argon (Ar) atmosphere, 1.50 g of Compound A, 3.70 g of Compound D, and 1.45 g of Pd(PPh ₃ ) ₄ and 2.66 g of K ₃ PO ₄ were added to a 100 mL three-neck flask, and the mixture was heated and refluxed in 80 mL of toluene solvent for 6 hours. . After air cooling, water was added to separate the organic layer, and the solvent was distilled. The obtained crude product was purified by silica gel column chromatography (using a mixed solvent of dichloromethane and hexane) and then recrystallized with a mixed solvent of toluene/hexane to obtain 3.2 g (yield) of the compound as a white solid. 82%) was obtained.

The molecular weight of the compound measured by FAB-MS measurement was 621. Through the above results, it was confirmed that the white solid compound was compound 124.

(Device creation example)

The organic electroluminescent devices of Examples 1 to 3 were manufactured using the above-described compounds 123, 124, and 127 as light-emitting layer materials.

[Example compounds]

The organic electroluminescent device of Comparative Example 1 was manufactured using Comparative Example Compound X-1 below as a light emitting layer material.

[Comparative Example Compound]

In the organic electroluminescent devices of Examples 1 to 3 and Comparative Example 1, the first electrode with a thickness of 150 nm was formed with ITO, and dipyrazino[2,3-f: 2',3'-h] quinoxaline-2,3,6 , 7,10,11-hexacarbonitrile (HAT-CN) was used to form a 10 nm thick hole injection layer, and N,N'-di(naphthalene-l-yl)-N,N'-diplienyl-benzidine (NPB) was used to form the hole injection layer. An 80 nm thick hole transport layer was formed, a 5 nm thick electron blocking layer was formed with mCP, and 18% of the example or comparative example compound was doped into (bis{2-[di(phenyl) phosphino]phenyl}ether oxide (DPEPO). A 20 nm thick light emitting layer was formed, a 10 nm hole blocking layer was formed with (bis{2-[di(phenyl) phosphino]phenyl}ether oxide (DPEPO), and 1,3,5-Tris(1-phenyl- A 30 nm thick electron transport layer was formed with 1H-benzimidazol-2-yl) benzene (TPBi), a 0.5 nm thick electron injection layer was formed with lithium fluoride (LiF), and a 100 nm thick second electrode was formed with Al. Each layer and the second electrode were formed using a vacuum evaporator and a resistance heating method.

Next, the maximum emission wavelength, delayed fluorescence lifetime, external quantum efficiency, and roll-off of the fabricated organic electroluminescent device were evaluated. The evaluation results are shown in Table 1 below. The maximum emission wavelength was the maximum emission wavelength of the emission spectrum at room temperature (about 300K). External quantum efficiency was measured using a C9920-12 device from Hamamatsu Photonics.

Device creation example luminescent layer λmax Delayed fluorescence lifetime
(??s) Roll-off ^{1 )}
(%) Example 1 Example Compound 123 460 100 0.68 Example 2 Example Compound 124 450 125 0.65 Example 3 Example Compound 127 440 100 0.75 Comparative Example 1 Comparative Example Compound X-1 450 900 0.2

1) Roll-off = EQE (cd/10mA) / EQE (max)

Through the results in Table 1, it can be seen that the aromatic compound according to an embodiment of the present invention is a thermally activated delayed fluorescence (TADF) material that emits blue light of 470 nm or less. Comparing Examples 1 to 3 and Comparative Example 1, it can be seen that the aromatic compound according to an embodiment of the present invention has a short delayed fluorescence life and a decrease in roll-off. Through this, the introduction of a linker with high steric hindrance suggests the effect of reducing roll-off by shortening the lifespan. In particular, in the case of compounds with large spin-orbit coupling and large steric effects, as in Example 1, the effect is maximized.

Above, embodiments of the present invention have been described with reference to the attached drawings, but those skilled in the art will understand that the present invention can be implemented in other specific forms without changing its technical idea or essential features. You will understand that it exists. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive.

10: Organic electroluminescent element EL1: First electrode
HTR: hole transport region EML: emitting layer
ETR: electron transport region EL2: second electrode

Claims (19)

Aromatic compound represented by the following formula (1):
[Formula 1]

In Formula 1,
R ₁ to R ₄ are each independently a hydrogen atom, a substituted or unsubstituted methyl group, or a substituted or unsubstituted phenyl group,
At least two of R ₁ to R ₄ are substituted or unsubstituted methyl groups, or substituted or unsubstituted phenyl groups,
A is represented by the following formula 2-6,
[Formula 2-6]

In Formula 2-6,
Q ₈ is a substituted or unsubstituted alkyl group with 1 to 15 carbon atoms, a substituted or unsubstituted aryl group with 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group with 2 to 30 ring carbon atoms,
h is an integer from 0 to 3,
In Formula 1,
D is represented by the following formula 3-2-1:
[Formula 3-2-1]

In the above formula 3-2-1,
L ₂ is a direct linkage or a substituted or unsubstituted arylene group having 6 to 30 ring carbon atoms,
R ₁₅ to R ₁₇ , and R ₂₀ to R ₂₂ are each independently a hydrogen atom, a deuterium atom, a halogen group, a substituted or unsubstituted silyl group, a substituted or unsubstituted alkyl group having 1 to 15 carbon atoms, or a substituted or unsubstituted alkyl group. It is an aryl group with 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group with 2 to 30 ring carbon atoms. According to paragraph 1,
Formula 1 is an aromatic compound represented by any one of the following formulas 1-1 to 1-4:
[Formula 1-1] [Formula 1-2]

[Formula 1-3] [Formula 1-4]

In Formulas 1-1 to 1-4,
R ₁ to R ₄ are each independently a substituted or unsubstituted methyl group, or a substituted or unsubstituted phenyl group,
A and D are the same as defined in claim 1. delete delete delete delete According to paragraph 1,
L ₂ is an aromatic compound that is a direct bond. According to paragraph 1,
The aromatic compound represented by Formula 1 is at least one selected from the compounds shown in Compound Group 1 below:
[Compound Group 1]


. first electrode;
a hole transport region provided on the first electrode;
a light-emitting layer provided on the hole transport region;
an electron transport region provided on the light emitting layer; and
Comprising a second electrode provided on the electron transport region,
The first electrode and the second electrode are each independently selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF/Ca, LiF/Al, Mo, Contains at least one selected from Ti, In, Sn, and Zn, two or more compounds selected from these, a mixture of two or more selected from these, or oxides thereof,
An organic electroluminescent device wherein at least one of the hole transport region, the light-emitting layer, and the electron transport region includes an aromatic compound represented by the following formula (1):
[Formula 1]

In Formula 1,
R ₁ to R ₄ are each independently a hydrogen atom, a substituted or unsubstituted methyl group, or a substituted or unsubstituted phenyl group,
At least two of R ₁ to R ₄ are substituted or unsubstituted methyl groups, or substituted or unsubstituted phenyl groups,
A is represented by the following formula 2-6,
[Formula 2-6]

In Formula 2-6,
Q ₈ is a substituted or unsubstituted alkyl group with 1 to 15 carbon atoms, a substituted or unsubstituted aryl group with 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group with 2 to 30 ring carbon atoms,
h is an integer from 0 to 3,
In Formula 1,
D is represented by the following formula 3-2-1:
[Formula 3-2-1]

In the above formula 3-2-1,
L ₂ is a direct linkage or a substituted or unsubstituted arylene group having 6 to 30 ring carbon atoms,
R ₁₅ to R ₁₇ , and R ₂₀ to R ₂₂ are each independently a hydrogen atom, a deuterium atom, a halogen group, a substituted or unsubstituted silyl group, a substituted or unsubstituted alkyl group having 1 to 15 carbon atoms, or a substituted or unsubstituted alkyl group. It is an aryl group with 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group with 2 to 30 ring carbon atoms. According to clause 9,
An organic electroluminescent device wherein the light-emitting layer includes an aromatic compound represented by Formula 1. According to clause 9,
The aromatic compound represented by Formula 1 is
An organic electroluminescent device in which the absolute value of the difference between the singlet energy level and the triplet energy level is 0.2 eV or less. According to clause 9,
The aromatic compound represented by Formula 1 is
An organic electroluminescent device that is a material for thermally activated delayed fluorescence. According to clause 9,
Formula 1 is an organic electroluminescent device represented by any one of the following formulas 1-1 to 1-4:
[Formula 1-1] [Formula 1-2]

[Formula 1-3] [Formula 1-4]

In Formulas 1-1 to 1-4,
R ₁ to R ₄ are each independently a substituted or unsubstituted methyl group, or a substituted or unsubstituted phenyl group,
A and D are the same as defined in claim 9. delete delete delete delete According to clause 9,
L ₂ is an organic electroluminescent device that is a direct bond. According to clause 9,
An organic electroluminescent device wherein the aromatic compound represented by Formula 1 is at least one selected from the compounds shown in Compound Group 1 below:
[Compound Group 1]


.

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