KR102575578B1 - Truxene derivative and organic electroluminescenece device including the same - Google Patents

Abstract

Provided is a truxen derivative having excellent film-forming properties when forming a layer and an organic electroluminescent device including the same. The truxen derivative is represented by the following formula (1)
[Formula 1]

Description

Truxen derivative and organic electroluminescent device containing the same

The present invention relates to a truxen derivative and an organic electroluminescent device including the same.

Recently, an organic electroluminescence display (OLED) is being developed. In addition, organic electroluminescence devices, which are self-emissive light emitting devices used in organic light emitting display devices, are actively being developed.

As a structure of an organic electroluminescent device, for example, a structure in which an anode, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and a cathode are sequentially laminated is known. In such an organic electroluminescent device, first, holes and electrons injected from the anode and the cathode recombine in the light emitting layer to generate excitons, and then, the generated excitons transition to a ground state to emit light.

Here, various compounds are being studied as materials for each layer in order to improve the performance of the organic electroluminescent device. For example, Patent Documents 1 to 3 disclose Truxene derivatives that can be used as constituent materials of each layer of an organic electroluminescent device.

WO 2006-005626 A JP 2006-135146 A JP 2003-261473 A

However, the truxen derivatives disclosed in Patent Literatures 1 to 3 do not have sufficient film-forming properties when forming a layer by a coating method. If the film formability is insufficient when forming the layer, unevenness occurs on the surface of the layer and the layer thickness becomes non-uniform, resulting in various problems, for example, non-uniform electric field applied. This may cause a short circuit or uneven light emission.

Here, the present invention has been made in view of the above problems, and an object of the present invention is to provide a truxen derivative excellent in film formability when forming a layer, and an organic electroluminescent device containing the truxen derivative. there is.

According to certain aspects of the present invention to solve the above problems, a truxen derivative represented by the following formula (1) is provided.

[Formula 1]

In Formula 1, R ₁ to R ₆ are each independently a hydrogen atom, a substituted or unsubstituted linear, branched or cyclic alkyl group having 1 to 16 carbon atoms, or a substituted or unsubstituted carbon atom 1 16 linear or branched alkoxy group, substituted or unsubstituted aryl group having 6 to 36 ring carbon atoms, or substituted or unsubstituted heterocyclyl group having 3 to 32 ring carbon atoms, and X ₁ is a substituted or unsubstituted di A benzofuranyl group, a substituted or unsubstituted dibenzothienyl group, a substituted or unsubstituted carbazolyl group, or a substituted or unsubstituted fluorenyl group, and X ₂ and X ₃ are each independently a hydrogen atom or a substituted or unsubstituted dibenzo group. A furanyl group, a substituted or unsubstituted dibenzothienyl group, a substituted or unsubstituted carbazolyl group, or a substituted or unsubstituted fluorenyl group.

According to this point of view, it is possible to provide a truxen derivative excellent in film formability when forming a layer.

X ₁ , X ₂ and X ₃ may be the same group.

According to this point of view, the film-forming properties of the truxen derivative can be further improved, and the production of the truxen derivative is relatively easy.

X ₁ , X ₂ and X ₃ are each independently a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothienyl group, a substituted or unsubstituted carbazolyl group or a substituted or unsubstituted fluorenyl group, and ,

Each of X ₁ , X ₂ and X ₃ may bind to the benzene ring portion of the truxene backbone.

According to this viewpoint, a conjugated system is formed between the truxen skeleton and X ₂ , X ₄ and X ₆ in the truxen derivative, and the electron donating function of the truxen derivative is enhanced.

R ₁ to R ₆ are each independently a hydrogen atom, a substituted or unsubstituted linear, branched or cyclic alkyl group having 1 to 7 carbon atoms, a substituted or unsubstituted linear or branched alkyl group having 1 to 7 carbon atoms It may be an alkoxy group of the shape, or a substituted or unsubstituted aryl group having 6 to 12 ring carbon atoms.

According to this point of view, the film-forming properties of the truxen derivative can be further improved.

R ₁ to R ₆ may each independently be a straight-chain alkyl group having 1 to 7 carbon atoms, a phenyl group or an alkylphenyl group.

According to this point of view, the film-forming properties of the truxen derivative can be further improved.

In addition, according to a separate aspect of the present invention to solve the above problems, an organic electroluminescent device including the truxen derivative is provided.

According to this point of view, since the surface irregularities of the layer containing the thruxen derivative in the organic electroluminescent element are reduced, problems caused by non-uniformity of each layer of the organic electroluminescent element, for example, applied It is possible to prevent electric leakage and light emission irregularities due to non-uniformity of the electric field.

The organic electroluminescent device may have a light emitting layer, a hole transport layer and/or a hole injection layer, and the light emitting layer, the hole transport layer and/or the hole injection layer may include the truxene derivative.

According to this point of view, it is possible to prevent, for example, electric leakage caused by non-uniformity of the applied electric field or uneven light emission, and to use the input power for light emission without waste, as a result of which the organic electroluminescent element emits light. Efficiency can be relatively high.

As described above, according to the present invention, it is possible to provide a truxen derivative excellent in film formability when forming a layer, and an organic electroluminescent device containing the truxen derivative.

1 is a schematic diagram showing an example of an organic electroluminescent device according to an embodiment of the present invention.
2 is a schematic diagram showing an example of an organic electroluminescent device according to another embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and drawings, the same reference numerals are given to components having substantially the same function and structure, so that redundant descriptions are omitted.

<1. Truxen Derivatives>

First, a truxen derivative according to an embodiment of the present invention will be described. The truxen derivative according to the present embodiment is a compound represented by Formula 1 below.

[Formula 1]

In Formula 1, R ₁ to R ₆ are each independently a hydrogen atom, a substituted or unsubstituted linear, branched or cyclic alkyl group having 1 to 16 carbon atoms, or a substituted or unsubstituted carbon atom 1 It is a linear or branched alkoxy group of 16 to 16, a substituted or unsubstituted aryl group having 6 to 36 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 3 to 32 ring carbon atoms. X ₁ is a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothienyl group, a substituted or unsubstituted carbazolyl group, or a substituted or unsubstituted fluorenyl group ) is Ki. X ₂ and X ₃ are each independently a hydrogen atom, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothienyl group, or a substituted or unsubstituted carbazolyl group. or a substituted or unsubstituted fluorenyl group.

The truxen derivative according to the present embodiment has an amorphous structure in the formed film. Therefore, the truxen derivative according to the present embodiment is excellent in film formability when forming a layer by a coating method or the like, and it is possible to form a film with few surface irregularities. Therefore, it is possible to prevent problems caused by non-uniformity of each layer of the organic electroluminescent device, for example, electric leakage due to non-uniformity of the applied electric field or irregular light emission.

In addition, since the truxen derivative according to the present embodiment has an amorphous structure in the formed film, the formed film has flexibility and excellent followability to a substrate or the like. Therefore, truxen derivatives are suitable for use in flexible organic electroluminescent devices.

In addition, as represented by Chemical Formula 1, the truxen derivative according to the present embodiment has a specific benzoheterole ring such as a dibenzofuranyl group or a fluorenyl group bonded to the truxen skeleton. . In general, compounds having a truxen skeleton have a hole transport function and/or a hole injection function, but such a group imparts an appropriate electron donating function to the truxen derivative, and as a result, the truxen derivative has bipolarity. In addition, when such a truxen derivative is used in an organic electroluminescent device, the charge balance of holes and electrons in the device is appropriately controlled, and the organic electroluminescent device has excellent luminous efficiency. In addition, by binding X ₁ to X ₃ to a predetermined position on the truxen skeleton, the degree of steric complexity in the truxen derivative is relatively low, and as a result, the truxen derivative is chemically stable.

Although not limited thereto, the truxene derivative according to the present embodiment is particularly suitable for use as a host material, a hole transport material, and a hole injection material of a light emitting layer in an organic electroluminescent device.

The number of carbon atoms in the linear, branched, or cyclic alkyl group in R ₁ to R ₆ in the above formula (1) may be within the above range, but is preferably 1 to 12, more preferably 1 to 7. In particular, the number of carbon atoms in the linear or branched alkyl group is preferably 1 to 6, more preferably 1 to 4. In addition, the number of carbon atoms in the cyclic alkyl group in particular should be within the above-mentioned range, but is preferably 3 to 7, more preferably 4 to 7. Moreover, among linear, branched, or cyclic alkyl groups, a straight-chain or branched alkyl group is preferable, and a straight-chain alkyl group is more preferable.

In addition, although it does not specifically limit as a linear, branched, or cyclic alkyl group in _R1 - _R6 , For example, a methyl group, an ethyl group, a propyl group, a butyl ( butyl) group, octyl group, decyl group, straight chain alkyl group such as pentadecyl group, and branched alkyl group such as t-butyl group, cyclobutyl group, cyclopentyl group ) group, cyclohexyl group, cycloalkyl group such as cycloheptyl group.

The number of carbon atoms in the linear or branched alkoxy group in R ₁ to R ₆ may be within the above range, but is preferably 1 to 12, more preferably 1 to 7, still more preferably 1 to 12. 6, more preferably 1 to 4. Moreover, a linear alkoxy group is preferable among the linear or branched alkoxy groups. In addition, although it does not specifically limit as said alkoxy group, For example, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, an octyloxy group, Straight-chain alkoxy groups, such as a decyloxy group and a pentadecyloxy group, and branched alkoxy groups, such as a t-butoxy group, are mentioned.

The number of ring carbon atoms in the aryl group may be within the above range, but is preferably 6 to 18, more preferably 6 to 12, still more preferably 4 to 7. In addition, as an aryl group, for example, a monocyclic aromatic group such as a phenyl group, a biphenyl group, a terphenyl group, a fluoroanthenyl group, a triphenylenyl group, non-condensed polycyclic aromatic groups such as naphthyl, anthryl, phenanthryl, fluorenyl, indenyl, pyrenyl ) group, condensed polycyclic aromatic groups such as acetonaphtenyl group, and the like.

The number of ring carbon atoms in the heterocyclyl group may be within the above range, but is preferably 4 to 18, more preferably 5 to 12.

As a heterocyclyl group, a heteroaryl group and a non-aromatic heterocyclyl group are mentioned, for example.

Examples of the heteroaryl group include pyridyl, furanyl, pyranyl, thienyl, quinolyl, and isoquinolyl. monocyclic heteroaryl groups such as groups, benzofuranyl groups, benzothienyl groups, indolyl groups, carbazolyl groups, benzoxazolyl groups, benzothia a benzothiazolyl group, a quinoxalyl group, a benzimidazolyl group, a pyrazolyl group, a dibenzofuranyl group, and a dibenzothienyl group; A cyclic heteroaryl group is mentioned.

As non-aromatic heterocyclyl group, for example, pyrrolidinyl group, tetrahydrofuranyl group, tetrahydrothiophenyl group, tetrahydropyranyl group, tetrahydrothio pyranyl group, piperidinyl group, 1, 4-dioxanyl group, 1, 4-oxathianyl group, morpholinyl group, 1, 4 - A dithianyl group, a piperazinyl group, a 1,4-azathianyl group, etc. may be mentioned.

R ₁ to R ₆ may be those described above, but each independently represents a hydrogen atom, a substituted or unsubstituted linear, branched or cyclic alkyl group having 1 to 7 carbon atoms, or a substituted or unsubstituted carbon atom having 1 to 7 carbon atoms. It is preferably a linear or branched alkoxy group or a substituted or unsubstituted ring-forming aryl group having 6 to 12 carbon atoms, more preferably a linear alkyl group, phenyl group or alkylphenyl group having 1 to 7 carbon atoms, and a methyl group , more preferably an ethyl group, an n-propyl group, a phenyl group or a methylphenyl group.

X ₂ and X ₃ may be groups defined in Formula 1, but preferably each independently is a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothienyl group, or a substituted or unsubstituted carbazolyl group. Or a substituted or unsubstituted fluorenyl group. Thereby, the electron donating function of the truxen derivative can be sufficient. In particular, when the truxen derivative is included in the light emitting layer, it can be said to have excellent electron injection properties as well as hole injectability into the light emitting layer.

In this case, any one of X ₁ to X ₃ is preferably one, and more preferably all are bonded to the truxene skeleton at the benzene ring site. As a result, a conjugated system is formed between the truxen skeleton and X ₁ to X ₃ in the truxen derivative, and the electron donating function of the truxen derivative is enhanced.

More specifically, in the above case, X ₁ to X ₃ are substituted or unsubstituted dibenzofuran-1-, dibenzofuran-2-, dibenzofuran-3- or dibenzofuran-4-yl, substituted or unsubstituted cyclic dibenzothiophene-1-, dibenzothiophene-2-, dibenzothiophene-3- or dibenzothiophen-4-yl, substituted or unsubstituted carbazole-1-, carbazole-2-, carbazol-3- or carbazol-4-yl, or substituted or unsubstituted fluorene-1-, fluorene-2-, fluorene-3- or fluoren-4-yl. X ₁ to X ₃ are preferably substituted or unsubstituted dibenzofuran-2- or dibenzofuran-4-yl, substituted or unsubstituted dibenzothiophen-2- or dibenzothiophen-4-yl, or substituted or unsubstituted carbazol-3-yl or substituted or unsubstituted fluoren-2- or fluoren-4-yl.

In addition, X ₁ to X ₃ may not be bonded to the truxene skeleton in the benzene ring region. Specifically, X ₁ to X ₃ may be substituted or unsubstituted carbazol-9-yl or substituted or unsubstituted fluoren-9-yl.

X ₁ to X ₃ may be different from each other, but it is preferable that two or more of them are the same group, and it is more preferable that all of them are the same group. This stabilizes the structure of the truxen derivative and makes it relatively easy and simple to produce the truxen derivative.

Although it does not specifically limit as a substituent which can be substituted in each group of _X1 - _X3 and _R1 - _R6 , For example, a cyano group, a silyl group, a C1-C10 mono( mono-, di- or tri-alkylsilyl group, straight-chain, branched, or cyclic alkyl group having 1 to 16 carbon atoms, or 1 to 16 carbon atoms and a straight-chain or branched alkoxy group, an aryl group having 6 to 36 ring carbon atoms, and a heterocyclyl group having 3 to 32 ring carbon atoms. In addition, the above substituents in each group of X ₁ to X ₃ and R ₁ to R ₆ are substituted with a hydrogen atom in X ₁ to X ₃ and R ₁ to R ₆ in the case of unsubstituted. Further, in each group of X ₁ to X ₃ and R ₁ to R ₆ , when two or more hydrogen atoms are substituted, a cyclic alkyl group, an aryl group, and/or a heterocyclyl group, including atoms to which the substituent and the substituent are bonded, is substituted. can be formed Also, in this case, the substituent may form a structure condensed with the truxene skeleton.

In addition, the specific examples of each substituent, the preferred number of carbon atoms, etc. are not particularly limited, but may be the same as those of each group of R ₁ to R ₆ described above.

In particular, the substituents of X ₁ to X ₃ are independently preferably a straight-chain or branched alkyl group having 1 to 6 carbon atoms or an aryl group having 4 to 18 carbon atoms for forming a ring, and , a methyl group, an ethyl group, a propyl group, a t-butyl group, a phenyl group, or a condensed benzene ring formed together with a benzene ring of X ₁ to X ₃ , and more preferably a methyl group or a phenyl group.

In addition, the substituent can be substituted at any site of each group of X ₁ to X ₃ and R ₁ to R ₆ .

Here, structural formulas of compounds 1 to 29, which are specific examples of the truxen derivative according to the present embodiment, are shown below. The truxen derivative according to the present embodiment may include at least one of the compounds shown in compound group 1 below. Among the compounds 1 to 29 shown below, compounds 1, 18, 22 and 24 are particularly preferred. However, the truxen derivative according to the present embodiment is not limited to the following compounds.

[Compound group 1]

In the above, the truxen derivative according to the present embodiment has been described in detail. Since the truxen derivative according to the present embodiment has an amorphous structure in the formed film, it is possible to form a film with excellent film formability and less irregularities on the surface. In addition, the formed film has flexibility and is excellent in followability to a substrate or the like. In addition, the truxen derivative according to the present embodiment has moderate bipolarity and is excellent in hole injection function and hole transport function. Therefore, by using the truxen derivative according to the present embodiment as a hole transport material, a hole injection material, and/or a host material of the light emitting layer, the charge balance in the organic electroluminescent device is appropriately controlled, and the organic electroluminescent device luminous efficiency can be improved.

In addition, the method for producing the truxen derivative according to the present embodiment is not particularly limited, and can be produced by a known method or the like.

<2. Organic Electroluminescent Device>

Next, referring to FIG. 1, an organic electroluminescent device using the truxen derivative according to the present embodiment will be described in detail. 1 is a schematic diagram showing an example of an organic electroluminescent device according to an embodiment of the present invention.

As shown in FIG. 1 , the organic electroluminescent device 100 according to the present embodiment includes a substrate 110, a first electrode 120 disposed on the substrate 110, and holes disposed on the first electrode 120. The injection layer 130, the hole transport layer 140 disposed on the hole injection layer 130, the light emitting layer 150 disposed on the hole transport layer 140, the electron transport layer 160 disposed on the light emitting layer 150, An electron injection layer 170 disposed on the electron transport layer 160 and a second electrode 180 disposed on the electron injection layer 170 are provided.

The truxen derivative according to the present embodiment may be included in, for example, the hole injection layer 130 , the hole transport layer 140 , and/or the light emitting layer 150 . This makes the layer containing the truxen derivative flat or uniform. Therefore, for example, it is possible to prevent a short circuit or uneven light emission due to non-uniformity of the applied electric field, and to use the input power for light emission without waste, resulting in the light emission efficiency of the organic electroluminescent device 100. can be relatively increased. Preferably, the truxen derivative according to the present embodiment is included in the light emitting layer 150. However, the layer containing the truxen derivative according to the present embodiment is not limited to the above. For example, the truxen derivative according to the present embodiment may be included in any organic layer between the first electrode 120 and the second electrode 180 .

As the substrate 110, a substrate used in a general organic light emitting device may be used. For example, the substrate 110 may be a glass substrate, a semiconductor substrate, or a transparent plastic substrate.

A first electrode 120 is formed on the substrate 110 . The first electrode 120 is, for example, an anode, and is formed as a transmissive electrode by using a material having a large work function among metals, alloys, or conductive compounds. Specifically, the first electrode 120 is transparent and has excellent conductivity of indium tin oxide (In ₂ O ₃ -SnO ₂ :ITO), indium zinc oxide (In ₂ O ₃ -ZnO), tin oxide (SnO ₂ ), It may be formed of zinc oxide (ZnO) or the like. In addition, the first electrode 120 may be formed as a reflective electrode in which magnesium (Mg), aluminum (Al), or the like is laminated on the transparent conductive layer.

A hole injection layer 130 is formed on the first electrode 120 . The hole injection layer 130 is a layer having a function of facilitating hole injection from the first electrode 120 and is formed to a thickness of, for example, about 10 nm to about 150 nm.

Here, the hole injection layer 130 may be formed of a truxene derivative according to the present embodiment. In addition, when the truxen derivative according to the present embodiment is included in another layer, the hole injection layer 130 may be formed of, for example, a compound represented by the following structural formula or a known hole transport material.

[Formula 2]

In addition, known hole injection materials capable of forming the hole injection layer 130 include, for example, triphenylamine-containing polyether ketone (TPAPEK), 4-isopropyl-4'-methyldiphenyliodonium tetrakis (pentane Fluorophenyl) borate (PPBI), N, N'-diphenyl-N, N'-bis-[4-(phenyl-m-tril-amino)-phenyl]-biphenyl-4, 4'-diamine ( DNTPD), phthalocyanine compounds such as copper phthalocyanine, 4,4', 4"-tris(3-methylphenylphenylamino)triphenylamine (m-MTDATA), N, N'-di(1-naphthyl)-N, N'-diphenylbenzidine (NPB), 4, 4', 4"-tris {N, N diphenylamino} triphenylamine (TDATA), 4, 4', 4"-tris (N, N-2- Naphthylphenylamino)triphenylamine (2-TNATA), polyaniline/dodecylbenzenesulfonic acid (PANI/DBSA), poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS) ), polyaniline/camphorsulphonic acid (PANI/CSA), or polyaniline/poly(4-styrenesulfonate) (PANI/PSS).

A hole transport layer 140 is formed on the hole injection layer 130 . The hole transport layer 140 is a layer having a function of transporting holes, and is formed to a thickness of, for example, about 10 nm to about 150 nm. Also, the hole transport layer 140 may be formed of a plurality of layers.

Here, the hole transport layer 140 may be formed by including the truxen derivative according to the present embodiment. In addition, when the truxen derivative according to the present embodiment is included in another layer, the hole transport layer 140 may be formed of a known hole transport material. Known hole transport materials include, for example, 1, 1-bis [(di-4-triylamino) phenyl] cyclohexane (TAPC), N-phenylcarbazole, polyvinylcarbazole ), carbazole derivatives such as N, N'-bis(3-methylphenyl)-N, N'-diphenyl-[1,1-biphenyl]-4,4'-diamine (TPD), 4,4' , 4″-tris(N-carbazolyl)triphenylamine (TCTA), and N,N′-di(1-naphthyl)-N,N′-diphenylbenzidine (NPB).

A light emitting layer 150 is formed on the hole transport layer 140 . The light emitting layer 150 is a layer that emits light by fluorescence, phosphorescence, or the like, and is formed to a thickness of, for example, about 10 nm to about 60 nm. The light emitting layer 150 may be formed of, for example, a mixed layer of a dopant material and a host material. Specifically, the light emitting layer 150 may be formed as a mixed layer doped with a dopant material in an amount of 0.1 to 50% by mass, preferably 0.1 to 20% by mass, based on the total mass of the host material.

Any host material and dopant material included in the light emitting layer 150 may be used as long as they are known host materials and dopant materials. For example, the light emitting layer 150 may include fluoranthene derivatives, pyrene (and derivatives thereof), acetylene derivatives, fluorene derivatives, perylene (and derivatives thereof), chrysene derivatives, or styryl derivatives as host materials or dopants. It can be included as a material. More specifically, the light emitting layer 150 is tris (8-quinolinolato) aluminum (Alq3), 4, 4'-N, N'-dicarbazole-biphenyl (CBP), poly (n-vinylcarbazole) (PVK), 4,4',4"-tris(N-carbazolyl)triphenylamine (TCTA), 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene (TPBI) , 3-tert-butyl-9, 10-di (naphtho-2-yl) anthracene (TBADN), distyryl arylene (DSA), 4, 4'-bis (9-carbazole) -2, 2' -Dimethyl-biphenyl (dmCBP), bis (2, 2-diphenyl vinyl) -1, 1'-biphenyl (DPVBi), 1, 4-bis (2- (3-N-ethylcarbazolyl) vinyl )Benzene (BCzVB), 4-(di-p-trilamino)-4′-((di-p-trilamino)styryl)stilbene (DPAVB), N-(4-((E)-2- (6-((E)-4-(diphenylamino)styryl)naphtharen-2-yl)vinyl)phenyl)-N-phenylbenzeneamine (N-BDAVBi), 2, 5, 8, 11-tetra -t-butylperylene (TBPe), 1, 1-dipyrene (1, 1-dipyrene), 1, 4-dipyrenylbenzene (1, 4-dipyrenylbenzene), 1, 4-bis (N, N-di Phenylamino)pyrene (1,4-bis(N,N-diphenylamino)pyrene) and the like may be included as a host material or a dopant material.

In addition, the light emitting layer 150 may be formed as a layer emitting light of a specific color. For example, the light emitting layer 150 may be formed as a red light emitting layer, a green light emitting layer, or a blue light emitting layer.

When the light emitting layer 150 is a blue light emitting layer, a known blue dopant may be used. For example, as a blue dopant, perlene and its derivatives, bis[2-(4,6-difluorophenyl)pyridinate]picolinate iridium(III) (FIrpic ), iridium (Ir) complexes, etc. can be used.

In addition, when the light emitting layer 150 is a red light emitting layer, a known red dopant may be used. For example, as a red dopant, rubrene and its derivatives, 4-dicyanomethylene-2-(p-dimethylamino styryl)-6-methyl-4H-pyran (DCM) and its derivatives, bis(1 -Phenylisoquinoline) (acetylacetonate) Iridium complexes such as iridium (III) (Ir(piq) ₂ (acac)), osmium (Os) complexes, platinum complexes, and the like can be used.

In addition, when the light emitting layer 150 is a green light emitting layer, a known green dopant may be used. For example, coumarin and its derivatives, tris[2-(p-tolyl)pyridine]iridium(III), Ir(mppy) ₃ ), tris Iridium complexes, such as (2-phenyl pyridine) iridium (III) ((Ir(ppy) ₃ ), etc. can be used.

Also, the host material may include the truxen derivative according to the present embodiment. In addition, when the truxen derivative according to the present embodiment is included in another layer, the host material may be formed of a known host.

Also, the host material may be a mixture of two or more types of compounds. For example, in order to adjust the charge balance of the organic electroluminescent device 100, the host material may include a compound having an electron transport function or a hole transport function by adding a compound that is a main component of the host material. there is.

More specifically, when the light emitting layer 150 includes the truxen derivative according to the present embodiment as a main component of the host material, a compound having an electron transport function may be further included as the host material. Thereby, the charge balance of the organic electroluminescent element 100 is further well controlled, and the luminous efficiency is improved. The compound having such an electron transport function is not particularly limited, and is selected, for example, from the electron transport materials described below in addition to the compounds that can be used as the host material described above. Preferable examples of the compound having an electron transport function that can be used as the host material are not particularly limited, but include quinolinol derivatives, imidazole derivatives, and pyridine derivatives. More specifically, tris(8-quinolinolato) aluminum (Alq3 ), 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene (TPBI), 1,3-bis[2-(2,2'-bipyridin-6-yl)-1, 3,4-oxadiazo-5-yl]benzene, 3,3',5,5'-tetra[(m-pyridyl)-phenyl-3-yl]biphenyl, and the like.

In this case, the host material is a truxen derivative according to the present embodiment and a compound having an electron transport function in a mass ratio of truxen derivative: compound having an electron transport function = 20: 1 to 1: 4, preferably. It is included in a ratio of 10:1 to 1:1.

An electron transport layer 160 is formed on the light emitting layer 150 . The electron transport layer 160 is a layer having a function of transporting electrons, and is formed to a thickness of about 15 nm to about 50 nm, for example. The electron transport layer 160 may be formed of, for example, a compound represented by the following structural formula.

[Formula 3]

In addition, the electron transport layer 160 may be formed of a known electron transport material. Examples of known electron transport materials include tris(8-hydroxyquinolinato)aluminium (Alq3) and compounds having a nitrogen-containing aromatic ring. Specific examples of the compound having a nitrogen-containing aromatic ring include oxidiazole derivatives such as 2-(4-tert-butylphenyl)-5-(4-biphenylyl)-1,3,4-oxydiazole. , 1, 3, 5-tri [(3-pyridyl) -phen-3-yl] benzene, a compound containing a pyridine ring, 2, 4, 6-tris (3'-(pyridin-3- Compounds containing triazine rings such as yl)biphenyl-3-yl)-1,3,5-triazine, 2-(4-(N-phenylbenzoimidazolyl-1-ylphenyl)-9,10-dimethylanthracene and and compounds containing the same imidazole ring.

An electron injection layer 170 is formed on the electron transport layer 160 . The electron injection layer 170 is a layer having a function of facilitating injection of electrons from the second electrode 180, and is formed to a thickness of about 0.3 nm to about 9 nm. As the material for forming the electron injection layer 170 , any known material can be used for the electron injection layer 170 . For example, the electron injection layer 170 may include Li complexes such as lithium 8-quinolinatoto (Liq) and lithium fluoride (LiF), sodium chloride (NaCl), cesium fluoride (CsF), lithium oxide (Li ₂ O), Alternatively, it may be formed of barium oxide (BaO) or the like.

A second electrode 180 is formed on the electron injection layer 170 . The second electrode 180 is, for example, a cathode, and is formed as a reflective electrode made of metal, alloy, or conductive compound having a low work function. The second electrode 180 may be, for example, a metal such as lithium (Li), magnesium (Mg), aluminum (Al), or calcium (Ca), or aluminum-lithium (Al-Li) or magnesium-indium (Mg- In), may be formed of a mixture of metals such as magnesium-silver (Mg-Ag). In addition, the second electrode 180 may be formed as a transmissive electrode by a thin film of the metal material of 20 nm or less or a transparent conductive film such as indium tin oxide or indium zinc oxide.

In addition, each layer described above may be formed by a known suitable film formation method depending on the material, such as a vacuum deposition method, a sputtering method, and various coating methods. Each organic layer disposed between the first electrode 120 and the second electrode 180 may be formed by, for example, various deposition methods and various coating methods. Here, the truxen derivative represented by Formula 1 can form an amorphous film even in a coating method in which crystals are generally easily formed, and can form a smooth layer. Therefore, when the layer containing the truxen derivative is formed by the application method, it has particularly excellent smoothness and uniformity of the layer compared to the case formed using conventional compounds. In addition, each metal layer such as the first electrode 120 and the second electrode 180 may be formed by, for example, a vacuum deposition method or a sputtering method.

In the above, an example of the organic electroluminescent device 100 according to the present embodiment has been described. Since the layer containing the truxene derivative according to the present embodiment in the organic electroluminescent device 100 has fewer surface irregularities, problems caused by non-uniformity of each layer of the organic electroluminescent device 100, example For example, it is possible to prevent electric leakage or uneven light emission due to non-uniformity of the applied electric field. In addition, since the organic electroluminescent device 100 according to the present embodiment includes the truxene derivative represented by Chemical Formula 1, the charge balance in the organic electroluminescent device 100 is appropriately adjusted, and the luminous efficiency this will be excellent

Next, an organic electroluminescent device according to another embodiment of the present invention will be described. 2 is a schematic diagram showing an example of an organic electroluminescent device according to an embodiment of the present invention.

As shown in FIG. 2 , the organic electroluminescent device 100A includes a substrate 110, a first electrode 120 disposed on the substrate 110, and a hole injection layer 130 disposed on the first electrode 120. , a light emitting layer 150A disposed on the hole injection layer 130, an electron injection layer 170 disposed on the light emitting layer 150A, and a second electrode 180 disposed on the electron injection layer 170. do.

Here, the substrate 110, the first electrode 120, the hole injection layer 130, the electron injection layer 170, and the second electrode 180 are the same as each member corresponding to the organic electroluminescent device 100. Since it has a configuration, the description is omitted.

The light emitting layer 150A is a layer that emits light by fluorescence, phosphorescence, or the like, and is formed to a thickness of, for example, about 10 nm to about 200 nm, preferably 1 to 100 nm. Here, the light emitting layer 150A includes the aforementioned truxen derivative. The light emitting layer 150A may be formed of, for example, a mixed layer of a dopant material and a host material. Specifically, the light emitting layer 150 may be formed of a mixed layer doped with a dopant material in an amount of 0.1 to 50% by mass, preferably 0.1 to 20% by mass, based on the total mass of the host material. In this case, for example, a truxen derivative can be used as the host material.

In addition, the host material may contain other compounds in addition to the thruxen derivatives described above. The light emitting layer 150A may further include, for example, a compound having an electron transport function as a host material. Thereby, the charge balance of the organic electroluminescent element 100 is further adjusted, and the luminous efficiency is improved. The compound having such an electron transport function may be the same as that described for the light emitting layer 150, and the ratio of the above-mentioned truxen derivative and the corresponding compound among the host materials may be the same.

In the above, an example of the organic electroluminescent device 100A according to the present embodiment has been described. Since the surface irregularities of the light emitting layer 150A are reduced in the organic electroluminescent device 100A according to the present embodiment, problems caused by non-uniformity of the light emitting layer 150A of the organic electroluminescent device 100A, for example , electric leakage due to non-uniformity of the applied electric field and uneven light emission are prevented. In addition, since the organic electroluminescent device 100A according to the present embodiment includes the truxene derivative represented by Chemical Formula 1, the charge balance in the organic electroluminescent device 100A is appropriately adjusted, and the luminous efficiency is improved. become excellent

In addition, the stacked structure of the organic electroluminescent devices 100 and 100A according to the present embodiment is not limited to the above example. The organic electroluminescent devices 100 and 100A according to the present embodiment may be formed in other known stacked structures. For example, the organic electroluminescent device 100 may not include at least one layer of the hole injection layer 130, the hole transport layer 140, the electron transport layer 160, and the electron injection layer 170, and Other layers may be provided. In addition, each layer of the organic electroluminescent device 100 or 100A may be formed as a single layer or may be formed as a plurality of layers.

In addition, the organic electroluminescent device 100 may include a hole blocking layer between the hole transport layer 140 and the light emitting layer 150 to prevent triplet excitons or holes from diffusing into the electron transport layer 160 . The hole blocking layer may be formed of, for example, an oxadiazole derivative, a triazole derivative, or a phenanthroline derivative.

[Example]

<3. Example>

Hereinafter, referring to Examples and Comparative Examples, a truxen derivative according to the present embodiment and an organic electroluminescent device including the truxen derivative will be described in detail. In addition, the examples shown below are only examples, and the truxen derivative and the organic electroluminescent device according to the present embodiment are not limited to the following examples.

[Synthesis of truxen derivatives]

First, truxen derivatives were synthesized according to the method described below.

(A) raw material

All of the reagents and solvents used in the starting materials and synthesis were of commercially available reagent grade, and were used without purification. In addition, dehydrated tetrahydrofuran (dehydrated THF) was purchased commercially and used as it was. In addition, as a filler used for column chromatography, spherical silica gel (neutral) manufactured by Kanto Chemical Co., Ltd. was used.

In addition, 3, 8, 13-tribromo 10, 15-dihydro-5H-diindeno [1, 2-a: 1 ', 2'-c] fluorene is described in B. Gomez-Lor, et al. , Eur. J. Org. Chem. Gomez-Lor, et al., Eur. J. Org. Chem. 2001, it was synthesized by referring to the method described in 2107-2114.

(B) Recognition method

Recognition was performed for each synthesized compound using proton nuclear magnetic resonance ( ¹ H NMR) spectroscopy and mass spectrometry (mass (MS) spectrum). ¹ H NMR spectrum was measured using a Jeol J NM-ECX400 spectrophotometer (400 MHz) or a Jeol J NM-ECS400 spectrophotometer (400 MHz). For MS spectrum measurement, α-cyano-4-hydroxycinnamic acid (CHCA) is used as a matrix to ionize a sample by a matrix assisted laser desorption ionization method (MALDI method), and a time-of-flight (TOF) mass spectrometer is used to analyze the MS spectrum. was measured (MALDI-TOF-MS spectrum). In addition, the MALDI-TOF-MS measurement was performed using a Shimadzu-Kratos AXIMA-CFR PLUS TOF mass spectrometer.

(C) synthesis

(Synthesis Example 1) Synthesis of Ph3-Tr (Comparative Example)

A compound (Ph3-Tr) represented by the following formula was synthesized according to the procedure described below.

[Formula 4]

(i) Synthesis of Br3-Tr

First, prior to the synthesis of Ph3-Tr, Br3-Tr, an intermediate in the synthesis of Ph3-Tr, was synthesized according to the following mechanism.

[Formula 5]

A 50 mL two-necked flask was dried up and 3,8,13-tribromo10,15-dihydro-5H-diindeno[1,2-a:1',2'-c]flu was prepared under a nitrogen atmosphere. Orene (alias; 3,8,13-truxene) (116 mg, 0.200 mmol) and dehydrated THF (5.0 mL) were added to the mixed solution and stirred in an ice bath. Then, potassium t-butoxy (180 mg, 1.60 mmol) was added to the mixed solution. At this time, the mixed solution changed from light yellow to dark red. After stirring for 1 hour, iodomethane (283 mg, 2.00 mmol) was added slowly, followed by stirring for another 2 hours. Subsequently, t-butoxypotassium (180 mg, 1.60 mmol) and iodomethane (283 mg, 2.00 mmol) were added in the same procedure as before, and after removing the ice bath, the mixture was stirred at room temperature for 12 hours. After completion of the reaction, the solvent was removed from the reaction mixture in an evaporator, chloroform was added to the reaction mixture, and insoluble matter was removed by filtration. The filtrate was concentrated again in an evaporator, and silica gel column chromatography ( Developing solvent; chloroform/hexane = 1/2, volume ratio) to obtain Br3-Tr (75.0 mg, 0.113 mmol, 57%) as an ivory-colored powder.

¹ H NMR (400 MHz, CDCl ₃ ) (Sigmaso) 8.36 (d, J = 1.8 Hz, 3H), 7.51 (dd, J = 7.9 and 1.8 Hz, 3H), 7.40 (d, J = 7.9 Hz, 3H) ), 1.83 (s, 18H); ¹³ C NMR (100 MHz, CDCl ₃ ) (Sigmaso) 156.13, 149.34, 138.53, 134.89, 129.98, 128.58, 124.09, 120.28, 46.84, 23.92; MALDI-TOF MS (m/z): [M+2] ⁺ calcd for C ₃₃ H ₂₇ Br ₃ , 661.96; found, 661.96.

(ii) Synthesis of Ph3-Tr

Subsequently, Ph3-Tr was synthesized according to the following mechanism.

[Formula 6]

Br3-Tr (332 mg, 0.501 mmol), phenylboronic acid (305 mg, 2.50 mmol), tetrakis(triphenylphosphine)palladium(0) (57.8 mg, 0.0500 mmol) were dissolved in toluene (17.5 mL) and ethanol. (4.0 mL) of the mixed solvent, and a nitrogen atmosphere was created in the reaction vessel. After adding potassium carbonate (691 mg, 5.00 mol) dissolved in water (4.0 mL) thereto, the resulting mixture was heated and stirred at 80°C for 15 hours. After the reaction mixture was allowed to cool to room temperature, it was concentrated by removing the solvent under reduced pressure. The residue after concentration was extracted with chloroform and water using a separatory funnel, and the resulting organic layer was dried over magnesium sulfate, and then the solvent was distilled off with an evaporator. After purification by silica gel column chromatography (developing solvent; chloroform/hexane = 1/2, volume ratio), recrystallization was performed from a hexane-ethyl acetate mixed solvent to obtain Ph3-Tr as a white solid (88.0 mg, 0.134 mmol, 27%).

¹ H NMR (400 MHz, CDCl ₃ ) δ8.56 (s, 3H), 7.74 (dd, J = 7.9 and 1.4 Hz, 6H), 7.64 (dd, J = 7.3 and 1.4 Hz, 3H), 7.62 (d , J = 7.3 Hz, 3H), 7.54 (t, J = 7.3 Hz, 3H), 7.42 (t, J = 7.3 Hz, 3H), 2.00 (s, 18H); ¹³ C NMR (100 MHz, CDCl ₃ )δ 156.66, 148.83, 142.07, 139.61, 137.34, 135.68, 128.96, 127.32, 127.13, 126.15, 124.67, 122.70, 46.75, 24.28; MALDI-TOF MS (m/z): M ⁺ calcd for C ₅₁ H ₄₂ , 654.33; found, 654.09.

(Synthesis Example 2) Synthesis of Compound 1 (Example)

Compound 1 was synthesized according to the following mechanism.

[Formula 7]

Br3-Tr (133 mg, 0.201 mmol), dibenzo[b,d]thiophen-4-ylboronic acid (205 mg, 0.899 mmol), tetrakis(triphenylphosphine)palladium(0) (23.4 mg, 0.0202 mmol) was added to a mixed solvent of toluene (7.1 mL) and ethanol (1.6 mL), and a nitrogen atmosphere was created in the reaction vessel. After adding potassium carbonate (276 mg, 2.00 mol) dissolved in water (1.6 mL) thereto, the resulting mixture was heated and stirred at 80°C or less for 20 hours. After the reaction mixture was allowed to cool to room temperature, it was concentrated by removing the solvent under reduced pressure. The residue after concentration was extracted with chloroform and water using a separatory funnel, and the resulting organic layer was dried over magnesium sulfate, and then the solvent was distilled off with an evaporator. After purification by silica gel column chromatography (developing solvent; chloroform/hexane = 2/3, volume ratio), recrystallization was performed from an ethyl acetate-ethanol mixed solvent to obtain compound 1 as a white solid (142 mg, 0.146 mmol, 73 %).

^OneH NMR (400 MHz, CDCl₃) δ8.66 (d, J = 1.4 Hz, 3H), 8.26-8.22 (m, 6H), 7,88 (dd, J = 7.3 and 1.4 Hz, 3H), 7.74 (dd, J = 7.7 and 1.4 Hz) , 3H), 7.67-7.61 (m, 9H), 7.53-7.47 (m, 6H), 2,00 (s, 18H);¹³C NMR (100 MHz, CDCl₃) δ157.51, 149.32, 139.81, 138.96, 138.86, 137.97, 137.43, 136.37, 136.01, 135.69, 127.33, 127.30, 126.90, 125.60, 125.36, 124.53, 122.91, 122.82, 121.89, 120.44, 47.02, 24.43; MALDI-TOF MS (m/z): M⁺ calcd for C₆₉H₄₈S₃, 972.29; found, 972.29.

(Synthesis Example 3) Synthesis of Compound 18 (Example)

Compound 18 was synthesized according to the following mechanism.

[Formula 8]

Br3-Tr (265 mg, 0.400 mmol), 2-(dibenzo[b,d]thiophen-2-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaboro Lan (496 mg, 1.60 mmol) and tetrakis(triphenylphosphine)palladium(0) (46.2 mg, 0.0400 mmol) were added to a mixed solvent of benzene (14 mL) and ethanol (3.2 mL), and the reaction vessel The inside was made into a nitrogen atmosphere. Potassium carbonate (544 mg, 4.00 mol) dissolved in water (3.2 mL) was added thereto, and the obtained mixture was heated and stirred at 80 °C or less for 14 hours. After the reaction mixture was allowed to cool to room temperature, it was concentrated by removing the solvent under reduced pressure. The residue after concentration was extracted with chloroform and water using a separatory separator, and the organic layer was dried over magnesium sulfate, and then the solvent was distilled off with an evaporator. After purification by silica gel column chromatography (developing solvent; chloroform/hexane = 1/2, volume ratio), compound 18 was obtained as a white solid (219 mg, 0.225 mmol, 56%) by recrystallization from ethyl acetate.

¹ H NMR (400 MHz, CDCl ₃ ) δ8.70 (s, 3H), 8.49 (d, J = 1.4 Hz, 3H), 8.26 (d, J = 7.7 Hz, 3H), 7.81 (dd, J = 8.7 and 1.8 Hz, 3H), 7.77 (dd, J = 7.7 and 1.3 Hz, 3H), 7.68-7.62 (m, 15H), 7.58 (d, J = 8.6 Hz, 3H), 7.54-7.43 (m, 9H) , 7.37-7.33 (m, 3H), 2.07 (s, 18H); ¹³ C NMR (100 MHz, CDCl ₃ ) δ156.13, 148.94, 141.50, 140.50, 140.43, 137.82, 137.54, 135.92, 134.50, 130.04, 127.63, 127.21, 126.3 9, 126.29, 125.79, 125.07, 124.10, 123.63, 122.77, 120.46, 120.18, 119.00, 110.33, 110.07, 46.88, 24.48; MALDI-TOF MS (m/z): M ⁺ calcd for C ₈₇ H ₆₃ N ₃ , 1149.50; found, 1149.20.

(Synthesis Example 4) Synthesis of Compound 22 (Example)

Compound 22 was synthesized according to the following mechanism.

[Formula 9]

Br3-Tr (133 mg, 0.201 mmol), 9-phenyl-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9H-carbazole (295 mg, 0.80 mmol) and tetrakistriphenylphosphine palladium (0) (23.3 mg, 0.0202 mmol) were added to a mixed solvent of toluene (7.1 mL) and ethanol (1.6 mL), and the reaction vessel was placed under a nitrogen atmosphere. angry After adding potassium carbonate (276 mg, 4.00 mol) dissolved in water (1.6 mL) thereto, the resulting mixture was heated and stirred at 80°C or lower for 18 hours. After the reaction mixture was allowed to cool to room temperature, it was concentrated by removing the solvent under reduced pressure. The residue after concentration was extracted with chloroform and water using a separatory separator, and the resulting organic layer was dried over magnesium sulfate, and then the solvent was distilled off with an evaporator. After purification by silica gel column chromatography (chloroform:hexane = 1:2), the obtained solid was dispersed in an appropriate amount of methanol and filtered with suction to obtain compound 22 as a white solid (88.0 mg, 0.0765 mmol, 38%).

¹ H NMR (400 MHz, CDCl ₃ ) δ8.70 (s, 3H), 8.49 (d, J = 1.4 Hz, 3H), 8.26 (d, J = 7.7 Hz, 3H), 7.81 (dd, J = 8.7 and 1.8 Hz, 3H), 7.77 (dd, J = 7.7 and 1.3 Hz, 3H), 7.68-7.62 (m, 15H), 7.58 (d, J = 8.6 Hz, 3H), 7.54-7.43 (m, 9H) , 7.37-7.33 (m, 3H), 2.07 (s, 18H); ¹³ C NMR (100 MHz, CDCl ₃ ) δ156.13, 148.94, 141.50, 140.50, 140.43, 137.82, 137.54, 135.92, 134.50, 130.04, 127.63, 127.21, 126.3 9, 126.29, 125.79, 125.07, 124.10, 123.63, 122.77, 120.46, 120.18, 119.00, 110.33, 110.07, 46.88, 24.48; MALDI-TOF MS (m/z): M ⁺ calcd for C ₈₇ H ₆₃ N ₃ , 1149.50; found, 1149.20.

(Synthesis Example 5) Synthesis of Compound 24 (Example)

Compound 24 was synthesized according to the following mechanism.

[Formula 10]

Br3-Tr (133 mg, 0.201 mmol), dibenzo[b,d]furan-4-ylboronic acid (191 mg, 0.901 mmol), tetrakis(triphenylphosphine)palladium(0) (23.3 mg, 0.0202 mmol) was added to a mixed solvent of toluene (7.1 mL) and ethanol (1.6 mL), and a nitrogen atmosphere was created in the reaction vessel. After adding potassium carbonate (276 mg, 2.00 mol) dissolved in water (1.6 mL) thereto, the obtained mixture was heated and stirred at 85 or less for 14 hours. After the reaction mixture was allowed to cool to room temperature, it was concentrated by removing the solvent under reduced pressure. The residue after concentration was extracted with chloroform and water using a separatory separator, and the resulting organic layer was dried over magnesium sulfate, and then the solvent was distilled off with an evaporator. After purification by silica gel column chromatography (developing solvent; chloroform/hexane = 1/2, volume ratio), recrystallization was performed from an ethyl acetate-ethanol mixed solvent to obtain compound 24 as a white solid (111 mg, 0.120 mmol, 60 %).

¹ H NMR (400 MHz, CDCl ₃ ) δ9.09 (s, 3H), 8.07 (d, J = 7.7 Hz, 3H), 8.02 (dd, J = 7.7 and 0.9 Hz, 3H), 7.87 (dd, J = 7.3 and 0.9 Hz, 3H), 7.78 (d, J = 7.2 Hz, 3H), 7.70 (d, J = 8.2 Hz, 3H), 7.63 (d, J = 8.2 Hz, 3H), 7.55-7.51 (m , 6H), 7.42 (t, J = 7.7 Hz, 3H), 2.10 (s, 18H); ¹³ C NMR (100 MHz, CDCl ₃ ) δ157.35, 156.39, 153.60, 149.08, 137.36, 135.90, 134.45, 127.46, 127.31, 126.97, 126.61, 126.56, 125.1 4, 124.52, 123.56, 122.98, 122.90, 120.95, 119.64, 111.87, 47.17, 24.31; MALDI-TOF MS (m/z): M ⁺ calcd for C ₆₉ H ₄₈ O ₃ , 924.36; found, 924.28.

[Production of organic electroluminescent device]

Subsequently, an organic electroluminescent device containing the truxen derivative according to the present embodiment was fabricated in the following procedure using a coating method.

(Example 1)

First, after patterning in advance, surface treatment by ultraviolet/ozone (O ₃ ) was performed on an ITO-glass substrate subjected to cleaning treatment. In addition, in the glass substrate, the film thickness of the ITO film (first electrode) was 150 nm.

Subsequently, a mixed solution (1:1, v/v) of water and isopropyl alcohol was added to 1.0 mL of PEDOT:PSS (Heraeus Co., Ltd., Clevios (trademark) PVP CH8000) stock solution, and a hole injection layer was formed. of the solution was obtained. Using this solution for forming a hole injection layer, spin coating was applied to an ITO-glass substrate at 2000 rpm for 2 seconds and then at 4000 rpm for 60 seconds. Thereafter, the ITO-glass substrate coated with the solution was dried at 105 for 60 minutes to form a hole injection layer (thickness: 40 nm) made of PEDOT:PSS.

Then, compound 1 as a truxen derivative: 5 mg, tris [2- (p-tolyl) pyridine] iridium (Tris [2- (p-tolyl) pyridine] iridium (III), Ir (mppy) ₃ ): 0.50 mg , 2-(4-tert-butylphenyl)-5-(4-biphenylyl)-1,3,4-oxydiazole (PBD): 1.0 mg was dissolved in chloroform: 0.35 mL, for forming a light emitting layer of the solution was obtained. Using this solution for forming the light emitting layer, spin coating was applied on the hole injection layer of the ITO-glass substrate at 2000 rpm for 10 seconds and then at 3000 rpm for 20 seconds. Thereafter, the ITO-glass substrate coated with the solution was dried at 80° C. for 30 minutes to form a light emitting layer (thickness: 68 nm).

Subsequently, the substrate was moved to a metal deposition machine, and an electron injection layer and a second electrode were deposited at a vacuum degree of 3.0 ^-4 Pa to 3.6 ^-4 Pa to manufacture an organic electroluminescent device. In addition, the electron injection layer was formed with a film thickness of 1 nm using CsF at a film formation rate of 0.1 Å/s, and the second electrode was formed with a film thickness of 250 nm using aluminum (Al). In the deposition of aluminum, film formation conditions were 50 nm in thickness at a film formation rate of 5.0 Å/s, followed by 200 nm in thickness at a film formation rate of 11.0 Å/s.

(Example 2)

An organic electroluminescent device was manufactured in the same manner as in Example 1, except that Compound 24 was used instead of Compound 1 as a truxen derivative.

[Evaluation of coating film and film formation]

(Examples 3 and 4 and Comparative Examples 1 and 2)

Compound 1, 22, 10, 15-dihydro-5H-diindeno [1, 2-a: 1', 2'-c] fluorene (10, 15-Dihydro-5H-diindeno [1, 2-a : 1', 2'-c] fluorene, truxene), and Ph3-Tr were evaluated for film formation. Specifically, first, as in Example 1, patterning of the ITO-glass substrate, cleaning, and formation of a hole injection layer (a layer made of PEDOT:PSS) were performed. Then, 5 mg of compound 1, 22, truxen or Ph3-Tr was dissolved in 0.3 mL of chloroform to prepare a truxen derivative solution. Using this truxen derivative solution, spin coating was applied on the hole injection layer of the ITO-glass substrate at 2000 rpm for 10 seconds and then at 3000 rpm for 20 seconds. Thereafter, the ITO-glass substrate coated with the solution was dried at 80°C for 30 minutes, and a truxen derivative layer was formed.

Surface roughness and film thickness of the formed truxen derivative layer were measured. In the measurement of surface roughness, using a nanoscale hybrid microscope VN-8010 (manufactured by Keyence Co., Ltd.) equipped with a standard cantilever OP-75041, the surface of each truxen derivative layer was measured over a range of 200 mx200 m, and JIS Arithmetic average roughness (Ra) based on B 0601-1994 was calculated. In the measurement of the film thickness, a cut surface was formed from the truxen derivative layer using a cutter, and the height difference between the cut surface portion and other portions was measured at a plurality of locations and calculated. The average value of the height difference was regarded as the thickness of the hole injection layer and the truxen derivative layer, and the thickness of the truxen derivative layer was calculated by subtracting 40 nm in thickness of the hole injection layer from the average value of the height difference. The results are shown in Table 1.

Corresponding Example compound film thickness (nm) surface roughness (nm) Example 3 compound 1 61.0 1.1 Example 4 compound 22 64.3 0.85 Comparative Example 1 Truxen 85.5 39.8 Comparative Example 2 Ph3-Tr 70.2 56.6

Referring to the results in Table 1, the truxen derivatives of Compounds 1 and 22 used in Examples 3 and 4 have extremely small surface roughness compared to the truxen and Ph3-Tr used in Comparative Examples 1 and 2. It can be seen that a derivative layer can be formed and the film formability is good. Therefore, the light-emitting layers formed in Examples 3 and 4 have a more uniform film thickness than those in Comparative Examples 1 and 2, and problems caused by non-uniformity of each layer of the light-emitting element, for example, non-uniformity of the applied electric field It is presumed that electric leakage and uneven light emission due to this are prevented more reliably.

[Evaluation of device characteristics]

The evaluation results of the organic electroluminescent devices according to Example 4 and Comparative Example 1 are shown in Table 2 below. In addition, C9920-11 Luminance Orientation Characteristic Measuring Device manufactured by Hamamatsu Photonics was used to evaluate the emission characteristics of the fabricated organic electroluminescent device.

Example compound Driving voltage (V) External quantum extraction efficiency (%) Example 1 compound 1 9.0 6.6 Example 2 compound 24 11.5 5.0

Referring to the results of Table 2, the truxen derivative according to the present embodiment exhibited good external proton extraction efficiency.

As can be seen from the above results, since the truxen derivative according to the present embodiment has the structure represented by the above-mentioned formula (1), it has excellent film formability when forming a layer. In addition, it is possible to prevent problems caused by non-uniformity of each layer of the organic electroluminescent device including the truxen derivative according to the present embodiment, for example, electric leakage or uneven light emission due to non-uniform applied electric field.

In the above, the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to these examples. It is clear that a person having ordinary knowledge in the technical field to which the present invention belongs will find various examples of change or modification within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It will be understood as belonging to.

100, 100A: organic electroluminescent device 500: substrate
120: first electrode 130: hole injection layer
140: hole transport layer 150, 150A: light emitting layer
160: electron transport layer 170: electron injection layer
180: second electrode

Claims (15)

A truxen derivative represented by Formula 1 below:
[Formula 1]

In Formula 1
R ₁ to R ₆ are each independently an unsubstituted, straight-chain alkyl group having 1 to 16 carbon atoms;
X ₁ to X ₃ are an unsubstituted dibenzofuranyl group, an unsubstituted dibenzothienyl group, or a carbazolyl group substituted with a phenyl group;
X ₁ to X ₃ are the same group. delete According to claim 1,
A truxene derivative wherein each of X ₁ , X ₂ and X ₃ is bonded to the benzene ring of the truxene skeleton. delete delete An organic electroluminescent device comprising a truxen derivative represented by Formula 1 below:
[Formula 1]

In Formula 1
R ₁ to R ₆ are each independently an unsubstituted, straight-chain alkyl group having 1 to 16 carbon atoms;
X ₁ to X ₃ are an unsubstituted dibenzofuranyl group, an unsubstituted dibenzothienyl group, or a carbazolyl group substituted with a phenyl group;
X ₁ to X ₃ are the same group. delete According to claim 6,
An organic electroluminescent device in which each of X ₁ , X ₂ and X ₃ is bonded to a benzene ring of a truxene skeleton. delete delete According to claim 6,
The truxen derivative is
An organic electroluminescent device comprising at least one of the compounds represented by the following compound group 1:
[Compound group 1]



. According to claim 6,
Including a light emitting layer,
The light emitting layer is an organic electroluminescent device comprising the truxen derivative. According to claim 6,
a hole transport layer,
The hole transport layer is an organic electroluminescent device comprising the truxen derivative. According to claim 6,
a hole injection layer;
The hole injection layer is an organic electroluminescent device comprising the truxen derivative. According to claim 1,
A truxen derivative comprising at least one of the compounds represented by the following compound group 1:
[Compound group 1]



.