Organic electroluminescent compound, organic electroluminescent material containing the same, and organic electroluminescent device

Abstract

The present disclosure relates to an organic electroluminescent compound, an organic electroluminescent material, and an organic electroluminescent device comprising the same. The organic electroluminescent compound of the present disclosure can provide an organic electroluminescent device with improved lifespan characteristics compared to an organic electroluminescent device comprising a conventional organic electroluminescent compound.

Description

Technical Field

[0001] The present disclosure relates to an organic electroluminescent compound, an organic electroluminescent material containing the same, and an organic electroluminescent device. Background Art

[0002] Among display devices, an electroluminescent device (EL device) is a self-luminous display device that has the advantages of providing a wider viewing angle, a larger contrast ratio, and a faster response time. The first organic EL device was developed by Eastman Kodak in 1987 by using small aromatic diamine molecules and an aluminum complex as materials for forming the light-emitting layer [Appl. Phys. Lett. 51, 913, 1987].

[0003] The most important factor that determines the luminous efficiency in an organic electroluminescent device is the luminescent material. So far, fluorescent materials have been widely used as luminescent materials. However, in view of the electroluminescence mechanism, phosphorescent luminescent materials have been widely studied because they theoretically enhance the luminous efficiency by four (4) times compared to fluorescent luminescent materials. Iridium (III) complexes are widely known as phosphorescent luminescent materials, including bis(2-(2'-benzothienyl)-pyridine-N, C-3')(acetylacetonato)iridium [(acac)Ir(btp)2], tris(2-phenylpyridine)iridium [Ir(ppy)3], and bis(4,6-difluorophenylpyridine-N, C2)picolinyliridium (Firpic), which are red, green, and blue luminescent materials, respectively.

[0004] Conventional technology uses 4,4'-N,N'-dicarbazole-biphenyl (CBP) as the most widely known phosphorescent host material. Recently, Pioneer Electronics (Japan) and others have developed a high-performance organic electroluminescent device using bathocuproine (BCP), a hole-blocking material, and aluminum(III) bis(2-methyl-8-quinolinolate)(4-phenylphenolate) (BAlq) as host materials.

[0005] Although these materials provide good luminescent characteristics, they have the following disadvantages: (1) Due to their low glass transition temperature and poor thermal stability, they may degrade during the high-temperature deposition process in a vacuum and may shorten the life of the device. (2) The power efficiency of an organic electroluminescent device is given by [(π / voltage)×current efficiency], and the power efficiency is inversely proportional to the voltage. Although an organic electroluminescent device containing a phosphorescent host material provides a higher current efficiency (cd / A) than an organic electroluminescent device containing a fluorescent material, a relatively high driving voltage is required. Therefore, there is no advantage in terms of power efficiency (lm / W). (3) In addition, the operating life of the organic electroluminescent device is short, and the luminescent efficiency is still in need of improvement. Therefore, the materials constituting the organic layer in the device, especially the host or dopant constituting the luminescent material, should be appropriately selected in order to achieve the excellent characteristics of the organic EL device.

[0006] Korean Patent No. 1477613 discloses an organic electroluminescent device using a substituted indolocarbazole compound as a host material; however, it does not disclose a compound having naphthalene as a linker.

[0007] Korean Patent No. 1313730 discloses a host material including a compound having a substituted indolocarbazole compound as a core and a naphthalene group as a linker; however, it does not disclose a compound having an asymmetric naphthalene linker. Summary of the Invention

[0008] Technical issues

[0009] The objects of the present disclosure are, first, to provide an organic electroluminescent compound capable of improving the lifespan characteristics of an organic electroluminescent device; second, to provide an organic electroluminescent material comprising the organic electroluminescent compound; and third, to provide an organic electroluminescent device comprising the organic electroluminescent compound having improved lifespan characteristics.

[0010] Solution to the problem

[0011] As a result of in-depth research to solve the above technical problems, the inventors of the present invention have found that it is possible to provide an organic electroluminescent device having low driving voltage and / or high luminous efficiency and / or long life characteristics by forming a structure in which a hole transport group and an electron transport group are asymmetrically connected through naphthalene as a linking group, thereby completing the present invention.

[0012] Specifically, the organic electroluminescent compound according to one embodiment (by connecting the indole and carbazole moiety that is easy to receive holes to the nitrogen-containing aromatic hexagonal ring group that is easy to receive electrons at the 1, 3 or 1, 6 positions (meta-type regiochemical position) of the naphthalene linker) has a high HOMO energy level because the electronic conjugation between the two modules is destroyed and the donor-acceptor electron bonding of the compound is weakened in the excited state. Due to this energy level, the hole current characteristics are improved, thereby improving the charge balance and enhancing the characteristics of the phosphorescent device. Therefore, compared with conventional compounds, the compound connected by the asymmetric naphthalene according to one embodiment can improve the efficiency of the organic electroluminescent device.

[0013] More specifically, the above-mentioned object can be achieved by an organic electroluminescent compound represented by Formula 1 below.

[0014]

[0015] in

[0016] X1 to X3 each independently represent CR 12 or N;

[0017] At least one of X1 to X3 represents N;

[0018] Ar1 to Ar3 each independently represent a substituted or unsubstituted (C1-C30)alkyl group, a substituted or unsubstituted (C6-C30)aryl group, or a substituted or unsubstituted (3- to 30-membered)heteroaryl group;

[0019] R1 to R3 and R 12 each independently represents hydrogen, deuterium, halogen, cyano, carboxyl, nitro, hydroxyl, substituted or unsubstituted (C1-C30) alkyl, substituted or unsubstituted (C3-C30) cycloalkyl, substituted or unsubstituted (C3-C30) cycloalkenyl, substituted or unsubstituted (3- to 7-membered) heterocycloalkyl, substituted or unsubstituted (C6-C30) aryl, or substituted or unsubstituted (3- to 30-membered) heteroaryl; or R1 and R3 may be linked with adjacent substituents to form a substituted or unsubstituted (C3-C30) monocyclic or polycyclic alicyclic ring or aromatic ring, or a combination thereof;

[0020] a and b each independently represent an integer from 0 to 4, c represents an integer from 0 to 2, when a or b is an integer of 2 or greater or c is 2, each R1, each R2 or each R3 may be the same or different;

[0021] L1 is represented by any one of the following formulas R-1 to R-3:

[0022]

[0023] in,

[0024] R4 represents hydrogen, deuterium, halogen, cyano, carboxyl, nitro, hydroxyl, substituted or unsubstituted (C1-C30)alkyl, substituted or unsubstituted (C3-C30)cycloalkyl, substituted or unsubstituted (C3-C30)cycloalkenyl, substituted or unsubstituted (3- to 7-membered)heterocycloalkyl, substituted or unsubstituted (C6-C30)aryl, or substituted or unsubstituted (3- to 30-membered)heteroaryl;

[0025] d represents an integer from 0 to 6. When d is an integer of 2 or greater, each R4 may be the same or different;

[0026] * indicates the connection position to the adjacent ring in Formula 1.

[0027] Beneficial effects of the present invention

[0028] By using the organic electroluminescent compound disclosed herein, an organic electroluminescent device having a long driving life can be provided. DETAILED DESCRIPTION

[0029] Hereinafter, the present disclosure will be described in detail. However, the following description is intended to explain the present invention and is not intended to limit the scope of the present invention in any way.

[0030] The term "organic electroluminescent compound" in the present disclosure means a compound that can be used in an organic electroluminescent device and can be contained in any layer constituting the organic electroluminescent device as needed.

[0031] The term "organic electroluminescent material" in this disclosure refers to a material that can be used in an organic electroluminescent device and can include at least one compound. If necessary, the organic electroluminescent material can be included in any layer constituting the organic electroluminescent device. For example, the organic electroluminescent material can be a hole injection material, a hole transport material, a hole assist material, a luminescence assist material, an electron blocking material, a luminescent material, an electron buffer material, a hole blocking material, an electron transport material, or an electron injection material.

[0032] Herein, “(C1-C30) alkyl” means a straight or branched chain alkyl group having 1 to 30 carbon atoms constituting the chain, wherein the number of carbon atoms is preferably 1 to 20, and more preferably 1 to 10. The above alkyl groups may include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, and the like. “(C2-C30) alkenyl” means a straight or branched chain alkenyl group having 2 to 30 carbon atoms constituting the chain, wherein the number of carbon atoms is preferably 2 to 20, and more preferably 2 to 10. The above alkenyl groups may include vinyl, 1-propenyl, 2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, 2-methylbut-2-enyl, and the like. “(C2-C30) alkynyl” means a straight or branched chain alkynyl group having 2 to 30 carbon atoms constituting the chain, wherein the number of carbon atoms is preferably 2 to 20, and more preferably 2 to 10. The above alkynyl groups may include ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, 1-methylpent-2-ynyl, and the like. "(C3-C30)cycloalkyl" is a monocyclic hydrocarbon or polycyclic hydrocarbon having 3 to 30 ring backbone carbon atoms, wherein the number of carbon atoms is preferably 3 to 20, and more preferably 3 to 7. The above cycloalkyl groups may include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and the like. The term "(3- to 7-membered)heterocycloalkyl" is a cycloalkyl group having 3 to 7, preferably 5 to 7, ring backbone atoms containing at least one heteroatom selected from B, N, O, S, Si, and P, and preferably O, S, and N. The above heterocycloalkyl groups may include tetrahydrofuran, pyrrolidine, tetrahydrothiophene (thiolan), tetrahydropyran, and the like. "(C6-C30)aryl" is a monocyclic or condensed ring group derived from an aromatic hydrocarbon having 6 to 30 ring backbone carbon atoms, wherein the number of ring backbone carbon atoms is preferably 6 to 20, more preferably 6 to 15, and may contain a spiro structure. The above aryl groups may include phenyl, biphenyl, terphenyl, naphthyl, binaphthyl, phenylnaphthyl, naphthylphenyl, fluorenyl, phenylfluorenyl, benzofluorenyl, dibenzofluorenyl, phenanthrenyl, phenylphenanthrenyl, anthracenyl, indenyl, triphenylene, pyrenyl, naphthacene, perylene, "(3- to 30-membered) heteroaryl" refers to an aryl group having 3 to 30 ring backbone atoms and containing at least one, preferably 1 to 4, heteroatoms selected from the group consisting of B, N, O, S, Si, and P. The above heteroaryl groups may be monocyclic or condensed rings condensed with at least one benzene ring; may be partially saturated; may be a heteroaryl group formed by linking at least one heteroaryl group or aryl group to a heteroaryl group via one or more single bonds; and may contain a spiro structure. The above heteroaryl groups may include monocyclic heteroaryl groups such as furyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, thiazolyl, thiadiazolyl, isothiazolyl, isoxazolyl, oxazolyl, oxadiazolyl, triazinyl, tetrazinyl, triazolyl, tetrazolyl, furazanyl, pyridyl, pyrazinyl, pyrimidinyl, and pyridazinyl, as well as fused ring heteroaryl groups such as benzofuranyl, benzothienyl, isobenzofuranyl, , dibenzofuranyl, dibenzothiophenyl, benzimidazolyl, benzothiazolyl, benzisothiazolyl, benzisoxazolyl, benzoxazolyl, isoindolyl, indolyl, indazolyl, benzothiadiazolyl, quinolyl, isoquinolyl, cinnolinyl, quinazolinyl, quinoxalinyl, carbazolyl, benzocarbazolyl, phenoxazinyl, phenothiazinyl, phenanthridinyl, benzodioxolyl, and dihydroacridinyl. "Halogen" includes F, Cl, Br, and I.

[0033] Herein, the "ring formed by connecting with adjacent substituents" means a substituted or unsubstituted (C3-C30) monocyclic or polycyclic alicyclic ring, aromatic ring, or a combination thereof formed by connecting or fusing two or more adjacent substituents; preferably, it is a substituted or unsubstituted (C3-C26) monocyclic or polycyclic alicyclic ring, aromatic ring, or a combination thereof. In addition, at least one of the carbon atoms in the formed ring may be replaced by at least one heteroatom selected from the group consisting of B, N, O, S, Si, and P, preferably N, O, and S.

[0034] In addition, the expression "substituted or unsubstituted" means that the hydrogen atom in a certain functional group is replaced by another atom or functional group (ie, a substituent). 12wherein the substituents of the substituted (C1-C30) alkyl, substituted (C3-C30) cycloalkyl, substituted (C3-C30) cycloalkenyl, substituted (3- to 7-membered) heterocycloalkyl, substituted (C6-C30) aryl, substituted (3- to 30-membered) heteroaryl, and substituted (C3-C30) monocyclic or polycyclic alicyclic ring, aromatic ring, or combination thereof are each independently at least one selected from the group consisting of deuterium, halogen, cyano, carboxyl, nitro alkyl, hydroxy, (C1-C30) alkyl, halogenated (C1-C30) alkyl, (C2-C30) alkenyl, (C2-C30) alkynyl, (C1-C30) alkoxy, (C1-C30) alkylthio, (C3-C30) cycloalkyl, (C3-C30) cycloalkenyl, (3- to 7-membered) heterocycloalkyl, (C6-C30) aryloxy, (C6-C30) arylthio, (C6-C30) aryl-substituted or unsubstituted (5- to 30-membered) heteroaryl, (5- to 30-membered)heteroaryl, substituted or unsubstituted (C6-C30)aryl, tri(C1-C30)alkylsilyl, tri(C6-C30)arylsilyl, di(C1-C30)alkyl(C6-C30)arylsilyl, (C1-C30)alkyldi(C6-C30)arylsilyl, amino, mono- or di-(C1-C30)alkylamino, (C1-C30)alkyl, substituted or unsubstituted mono- or di-(C6-C30)alkyl )arylamino, (C1-C30)alkyl(C6-C30)arylamino, (C1-C30)alkylcarbonyl, (C1-C30)alkoxycarbonyl, (C6-C30)arylcarbonyl, di(C6-C30)arylboronyl, di(C1-C30)alkylboronyl, (C1-C30)alkyl(C6-C30)arylboronyl, (C6-C30)aryl(C1-C30)alkyl, and (C1-C30)alkyl(C6-C30)aryl.

[0035] Hereinafter, an organic electroluminescent compound according to one embodiment will be described in more detail.

[0036] The organic electroluminescent compound according to one embodiment is represented by Formula 1 below.

[0037]

[0038] In formula 1,

[0039] X1 to X3 each independently represent CR 12 or N;

[0040] At least one of X1 to X3 represents N;

[0041] Ar1 to Ar3 each independently represent a substituted or unsubstituted (C1-C30)alkyl group, a substituted or unsubstituted (C6-C30)aryl group, or a substituted or unsubstituted (3- to 30-membered)heteroaryl group;

[0042] R1 to R3 and R 12 each independently represents hydrogen, deuterium, halogen, cyano, carboxyl, nitro, hydroxyl, substituted or unsubstituted (C1-C30) alkyl, substituted or unsubstituted (C3-C30) cycloalkyl, substituted or unsubstituted (C3-C30) cycloalkenyl, substituted or unsubstituted (3- to 7-membered) heterocycloalkyl, substituted or unsubstituted (C6-C30) aryl, or substituted or unsubstituted (3- to 30-membered) heteroaryl; or R1 and R3 may be linked with adjacent substituents to form a substituted or unsubstituted (C3-C30) monocyclic or polycyclic alicyclic ring or aromatic ring, or a combination thereof;

[0043] a and b each independently represent an integer from 0 to 4, c represents an integer from 0 to 2, when a or b is an integer of 2 or greater or c is 2, each R1, each R2 or each R3 may be the same or different;

[0044] L1 is represented by any one of the following formulas R-1 to R-3:

[0045]

[0046] In formulas R-1 to R-3,

[0047] R4 represents hydrogen, deuterium, halogen, cyano, carboxyl, nitro, hydroxyl, substituted or unsubstituted (C1-C30)alkyl, substituted or unsubstituted (C3-C30)cycloalkyl, substituted or unsubstituted (C3-C30)cycloalkenyl, substituted or unsubstituted (3- to 7-membered)heterocycloalkyl, substituted or unsubstituted (C6-C30)aryl, or substituted or unsubstituted (3- to 30-membered)heteroaryl;

[0048] d represents an integer from 0 to 6. When d is an integer of 2 or greater, each R4 may be the same or different;

[0049] * indicates the connection position to the adjacent ring in Formula 1.

[0050] In one embodiment, in Formula 1, L1 represents a substituted or unsubstituted naphthalene, which can be represented by the following formula a, for example, the 1- and 3-carbons, 1- and 6-carbons, 3- and 6-carbons, 3- and 8-carbons, or 6- and 8-carbons of naphthalene can be respectively connected to adjacent rings; or the 2- and 4-carbons, 2- and 5-carbons, 2- and 7-carbons, 4- and 7-carbons, or 2- and 7-carbons of naphthalene can be respectively connected to adjacent rings.

[0051]

[0052] Specifically, L1 may be represented by any one of the following formulae R-1 to R-3, that is, L1 is asymmetrically linked to indolocarbazole and a nitrogen-containing aromatic hexagonal ring group, which are adjacent substituents.

[0053] An organic light-emitting device according to one embodiment has a low driving voltage and / or high luminous efficiency and / or a long lifespan by including the organic electroluminescent compound represented by Formula 1. The above effects are achieved by connecting an indole-carbazole moiety as a hole-transporting group and a nitrogen-containing aromatic hexagonal ring group as an electron-transporting group at the above specific position of naphthalene, thereby disrupting the electron conjugation between the hole-transporting group and the electron-transporting group.

[0054] Formula 1 according to one embodiment may be represented by any one of the following Formulas 1-1 to 1-5.

[0055]

[0056] In formulas 1-1 to 1-5,

[0057] X1 to X3, Ar1 to Ar3, R1 to R4, and a to d are as defined in Formula 1.

[0058] In one embodiment, Ar1 to Ar3 each independently represent a substituted or unsubstituted (C6-C25) aryl group, preferably a substituted or unsubstituted (C6-C18) aryl group. For example, Ar1 to Ar3 each independently represent a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, or a substituted or unsubstituted naphthyl group.

[0059] In one embodiment, R1 to R4 and R 12 Each independently represents hydrogen, deuterium, halogen, cyano, carboxyl, nitro, hydroxyl, or substituted or unsubstituted (C1-C20) alkyl, preferably each independently may be hydrogen, deuterium, halogen, cyano, carboxyl, nitro, hydroxyl, or substituted or unsubstituted (C1-C10) alkyl. For example, R1 to R4 and R 12 It can all be hydrogen.

[0060] In one embodiment, at least two of X1 to X3 may be N. For example, X1 and X2 may be N, and X3 may be CR 12 , for example X1 and X3 can be N, and X2 can be CR 12 , for example X2 and X3 can be N, and X3 can be CR 12 .

[0061] In one embodiment, X1 to X3 may all be N.

[0062] In Formula 1, the heteroaryl group contains at least one heteroatom selected from B, N, O, S, Si and P, preferably, may contain at least one heteroatom selected from N, O and S, more preferably, may contain at least one N.

[0063] In Formula 1, a, b, c, and d preferably each independently represent an integer of 0 or 1. For example, a, b, c, and d may all be 0.

[0064] According to one embodiment of the present disclosure, the organic electroluminescent compound may be represented by any one of the following Formulae 2 to 7.

[0065]

[0066]

[0067] In equations 2 to 7,

[0068] L1, X1 to X3, Ar1 to Ar3, R1 to R3, and a to c are as defined in Formula 1.

[0069] According to one embodiment of the present disclosure, in Formula 1, at least two of X1 to X3 represent N, Ar1 to Ar3 each independently represent a substituted or unsubstituted (C6-C25) aryl group, R1 to R4 and R 12 Each independently represents hydrogen or deuterium, and a, b, c and d each independently represent an integer of 0 or 1.

[0070] According to another embodiment of the present disclosure, in Formula 1, X1 to X3 all represent N, Ar1 to Ar3 each independently represent a substituted or unsubstituted (C6-C18) aryl group, R1 to R4 and R 12 All represent hydrogen, and a, b, c and d all represent 0.

[0071] The compound represented by Formula 1 can be more specifically illustrated by the following compounds, but is not limited thereto:

[0072]

[0073]

[0074]

[0075]

[0076]

[0077]

[0078]

[0079]

[0080]

[0081]

[0082]

[0083]

[0084] The present disclosure may provide an organic electroluminescent material including an organic electroluminescent compound having Formula 1, and an organic electroluminescent device including the material.

[0085] The organic electroluminescent material according to one embodiment may consist of the organic electroluminescent compound of the present disclosure as a sole compound, or may further include conventional materials generally used in organic electroluminescent materials.

[0086] Meanwhile, the organic electroluminescent device of the present disclosure may include a first electrode, a second electrode, and at least one organic layer between the first electrode and the second electrode. The organic layer may include at least one organic electroluminescent compound having Formula 1. The organic layer may further include at least one compound selected from the group consisting of arylamine-based compounds and styrylarylamine-based compounds. In addition, the organic layer may further include at least one metal selected from the group consisting of: a metal of Group 1 of the periodic table, a metal of Group 2, a transition metal of Period 4, a transition metal of Period 5, an organometallic of a lanthanide element, and a d-transition element, or at least one complex compound comprising said metal.

[0087] One of the first electrode and the second electrode may be an anode, and the other may be a cathode. The organic layer may include a light-emitting layer, and may further include at least one layer selected from a hole injection layer, a hole transport layer, a hole auxiliary layer, a light-emitting auxiliary layer, an electron transport layer, an electron injection layer, an intermediate layer, a hole blocking layer, an electron blocking layer, and an electron buffer layer.

[0088] A hole injection layer, a hole transport layer, an electron blocking layer, or a combination thereof can be used between the anode and the light-emitting layer. The hole injection layer can be a multilayer to reduce the hole injection barrier (or hole injection voltage) from the anode to the hole transport layer or the electron blocking layer, wherein each of the multilayers can use two compounds at the same time. The electron blocking layer can be placed between the hole transport layer (or hole injection layer) and the light-emitting layer, and can confine excitons in the light-emitting layer by blocking electrons from overflowing from the light-emitting layer to prevent luminescence leakage. The hole transport layer or the electron blocking layer can also be a multilayer, wherein each layer can use a variety of compounds.

[0089] An electron buffer layer, hole blocking layer, electron transport layer, electron injection layer, or a combination thereof may be used between the light-emitting layer and the cathode. The electron buffer layer may be multilayered to control electron injection and improve the interface properties between the light-emitting layer and the electron injection layer, wherein each of the multilayers may use two compounds simultaneously. The hole blocking layer or electron transport layer may also be multilayered, wherein each layer may use multiple compounds.

[0090] The luminescence auxiliary layer can be placed between the anode and the light-emitting layer, or between the cathode and the light-emitting layer. When the luminescence auxiliary layer is placed between the anode and the light-emitting layer, it can be used to promote hole injection and / or hole transport, or to prevent electron overflow. When the luminescence auxiliary layer is placed between the cathode and the light-emitting layer, it can be used to promote electron injection and / or electron transport, or to prevent hole overflow. Moreover, the hole auxiliary layer can be placed between the hole transport layer (or hole injection layer) and the light-emitting layer, and can effectively promote or block the hole transport rate (or hole injection rate), thereby enabling control of charge balance. When the organic electroluminescent device includes two or more hole transport layers, the hole transport layer further included can be used as a hole auxiliary layer or an electron blocking layer. The luminescence auxiliary layer, the hole auxiliary layer or the electron blocking layer can have the effect of improving the efficiency and / or life of the organic electroluminescent device.

[0091] In the organic electroluminescent device of the present disclosure, preferably, at least one layer selected from a chalcogenide layer, a metal halide layer, and a metal oxide layer (hereinafter, "surface layer") can be placed on one or more inner surfaces of one or both electrodes. Specifically, it is preferred to place a chalcogenide (including oxide) layer of silicon or aluminum on the anode surface of the electroluminescent medium layer, and it is preferred to place a metal halide layer or a metal oxide layer on the cathode surface of the electroluminescent medium layer. The operational stability of the organic electroluminescent device can be obtained by the surface layer. Preferably, the chalcogenide includes SiO X (1≤X≤2), AlO X (1≤X≤1.5), SiON, SiAlON, etc.; metal halides include LiF, MgF2, CaF2, rare earth metal fluorides, etc.; and metal oxides include Cs2O, Li2O, MgO, SrO, BaO, CaO, etc.

[0092] In the organic electroluminescent device disclosed herein, a mixed region of an electron transport compound and a reductive dopant, or a mixed region of a hole transport compound and an oxidative dopant can be placed on at least one surface of a pair of electrodes. In this case, the electron transport compound is reduced to anions, and thus it becomes easier to inject and transport electrons from the mixed region to the electroluminescent medium. In addition, the hole transport compound is oxidized to cations, and thus it becomes easier to inject and transport holes from the mixed region to the electroluminescent medium. Preferably, the oxidative dopant includes various Lewis acids and acceptor compounds, and the reductive dopant includes alkali metals, alkali metal compounds, alkaline earth metals, rare earth metals, and mixtures thereof. The reductive dopant layer can be used as a charge generation layer to prepare an organic electroluminescent device having two or more light-emitting layers and emitting white light.

[0093] The organic electroluminescent compound represented by Formula 1 may be included in the light-emitting layer. When used in the light-emitting layer, the organic electroluminescent compound having Formula 1 may be included as a host material. Preferably, the light-emitting layer may further include at least one dopant. If necessary, another compound other than the organic electroluminescent compound having Formula 1 may be further included as a second host material. In this article, the weight ratio of the first host material to the second host material is 1:99 to 99:1.

[0094] The second host material may use any known phosphorescent host. In terms of luminous efficiency, the second host material may be particularly preferably selected from the group consisting of compounds represented by the following formulae 11 to 16.

[0095] H-(Cz-L4) h -M---(11)

[0096] H-(Cz) i -L4-M---(12)

[0097]

[0098] In equations 11 to 15,

[0099] Cz represents the following structure:

[0100]

[0101] A represents -O- or -S-;

[0102] R 21 to R 24 Each independently represents hydrogen, deuterium, halogen, substituted or unsubstituted (C1-C30) alkyl, substituted or unsubstituted (C6-C30) aryl, substituted or unsubstituted (5- to 30-membered) heteroaryl, or -SiR 25 R26 R 27 , where R 25 to R 27 Each independently represents a substituted or unsubstituted (C1-C30) alkyl group, or a substituted or unsubstituted (C6-C30) aryl group; L4 represents a single bond, a substituted or unsubstituted (C6-C30) arylene group, or a substituted or unsubstituted (5- to 30-membered) heteroarylene group; M represents a substituted or unsubstituted (C6-C30) aryl group, or a substituted or unsubstituted (5- to 30-membered) heteroaryl group; Y1 and Y2 each independently represent -O-, -S-, -N(R 31 )-or–C(R 32 )(R 33 )-, the premise is that Y1 and Y2 do not exist at the same time; R 31 to R 33 Each independently represents a substituted or unsubstituted (C1-C30)alkyl group, a substituted or unsubstituted (C6-C30)aryl group, or a substituted or unsubstituted (5- to 30-membered)heteroaryl group, R 32 and R 33 may be the same or different; h and i each independently represent an integer from 1 to 3; j, k, l and v each independently represent an integer from 0 to 4; u represents an integer from 0 to 3; when h, i, j, k, l, u or v represents an integer of 2 or greater, each (Cz-L4), each (Cz), each R 21 , each R 22 , each R 23 , or each R 24 Can be the same or different;

[0103]

[0104] In Equation 16,

[0105] Y3 to Y5 each independently represent CR 34 or N;

[0106] R 34 represents hydrogen, substituted or unsubstituted (C1-C30)alkyl, substituted or unsubstituted (C6-C30)aryl, or substituted or unsubstituted (5- to 30-membered)heteroaryl;

[0107] B1 and B2 each independently represent hydrogen, substituted or unsubstituted (C6-C30)aryl, or substituted or unsubstituted (5- to 30-membered)heteroaryl;

[0108] B3 represents a substituted or unsubstituted (C6-C30)aryl group, or a substituted or unsubstituted (5- to 30-membered)heteroaryl group;

[0109] L5 represents a single bond, a substituted or unsubstituted (C6-C30)arylene group, or a substituted or unsubstituted (5- to 30-membered)heteroarylene group.

[0110] Specifically, preferred examples of the second host material are as follows:

[0111]

[0112]

[0113]

[0114]

[0115]

[0116]

[0117]

[0118]

[0119] [wherein TPS represents triphenylsilyl]

[0120] The dopant contained in the organic electroluminescent device of the present disclosure is preferably at least one phosphorescent dopant. The phosphorescent dopant material used in the organic electroluminescent device of the present disclosure is not particularly limited, but can be preferably selected from metallized iridium (Ir), osmium (Os), copper (Cu), and platinum (Pt) complex compounds, more preferably selected from ortho-metallized iridium (Ir), osmium (Os), copper (Cu), and platinum (Pt) complex compounds, and even more preferably ortho-metallized iridium complex compounds.

[0121] The dopant included in the organic electroluminescent device of the present disclosure may include a compound represented by the following Formula 101:

[0122]

[0123] In formula 101,

[0124] Wherein, L is selected from the following structures 1 or 2:

[0125]

[0126] R 100 to R 103each independently represents hydrogen, deuterium, halogen, halogen-substituted or unsubstituted (C1-C30)alkyl, substituted or unsubstituted (C3-C30)cycloalkyl, substituted or unsubstituted (C6-C30)aryl, cyano, substituted or unsubstituted (3- to 30-membered)heteroaryl, or substituted or unsubstituted (C1-C30)alkoxy; or R 100 to R 103 May be linked to adjacent substituents to form a substituted or unsubstituted fused ring, for example, substituted or unsubstituted quinoline, substituted or unsubstituted benzofuranopyridine, substituted or unsubstituted benzothienopyridine, substituted or unsubstituted indenopyridine, substituted or unsubstituted benzofuranoquinoline, substituted or unsubstituted benzothienoquinoline, or substituted or unsubstituted indenoquinoline;

[0127] R 104 to R 107 each independently represents hydrogen, deuterium, halogen, halogen-substituted or unsubstituted (C1-C30)alkyl, substituted or unsubstituted (C3-C30)cycloalkyl, substituted or unsubstituted (C6-C30)aryl, substituted or unsubstituted (3- to 30-membered)heteroaryl, cyano, or substituted or unsubstituted (C1-C30)alkoxy; or R 104 to R 107 May be linked to adjacent substituents to form a substituted or unsubstituted fused ring, for example, substituted or unsubstituted naphthyl, substituted or unsubstituted fluorene, substituted or unsubstituted dibenzothiophene, substituted or unsubstituted dibenzofuran, substituted or unsubstituted indenopyridine, substituted or unsubstituted benzofuranopyridine, or substituted or unsubstituted benzothienopyridine;

[0128] R 201 to R 211 Each independently represents hydrogen, deuterium, halogen, halogen-substituted or unsubstituted (C1-C30)alkyl, substituted or unsubstituted (C3-C30)cycloalkyl, or substituted or unsubstituted (C6-C30)aryl; R 201 to R 211 May be linked to adjacent substituents to form a substituted or unsubstituted fused ring;

[0129] n represents an integer of 1 to 3.

[0130] Specific examples of the dopant compound include the following, but are not limited thereto:

[0131]

[0132]

[0133]

[0134]

[0135] To form each layer of the organic electroluminescent device of the present disclosure, a dry film forming method such as vacuum evaporation, sputtering, plasma, ion plating, etc., or a wet film forming method such as spin coating, dip coating, flow coating, etc. can be used. When forming a layer from the dopant and host compound of the present disclosure, co-evaporation or mixed evaporation can be used, but is not limited thereto.

[0136] When a wet film-forming method is used, a thin film can be formed by dissolving or diffusing the material forming each layer in any suitable solvent such as ethanol, chloroform, tetrahydrofuran, dioxane, etc. The solvent may be any solvent in which the material forming each layer can be dissolved or diffused and in which there is no problem in film-forming ability.

[0137] Co-deposition is a mixed deposition method in which two or more isomeric materials are placed in corresponding single crucible sources and current is applied to two chambers at the same time to evaporate the materials and perform mixed deposition; and mixed deposition is a mixed deposition method in which two or more isomeric materials are mixed in one crucible source before being deposited and then current is applied to one chamber to evaporate the materials.

[0138] Furthermore, the organic electroluminescent device of the present disclosure can be used to manufacture display devices such as smartphones, tablet computers, notebook computers, PCs, TVs, or display devices for vehicles, or lighting devices such as outdoor or indoor lighting.

[0139] Hereinafter, a preparation method of a subject compound according to the present disclosure and characteristics of a device including the same will be explained in detail with reference to representative compounds of the present disclosure in order to understand the present disclosure in detail.

[0140] [Example 1] Preparation of Compound C-193

[0141]

[0142] Preparation of compound 1

[0143] 5-aminonaphthalene-2-ol (70g, 440mmol) and the methanol of 1.7L are added in flask and dissolve.Next, the HCl of 400mL and the water of 640mL are added thereto, and at room temperature stirred 2 minutes.Sodium nitrite (30.34g, 440mmol) is added in above flask and after stirring 30 minutes, two (pinacolato) diboron (167g, 660mmol) are added thereto, and mixture was at room temperature stirred 24 hours.After reaction is completed, organic layer is extracted with ethyl acetate, then remove residual moisture and dry with magnesium sulfate, and products therefrom is passed through column chromatography to obtain compound 1 (27g, productive rate: 22%).

[0144] Preparation of compound 2

[0145] Compound 1 (27 g, 100 mmol), 2-chloro-4,6-diphenyl-1,3,5-triazine (26.7 g, 100 mmol), tetrakis(triphenylphosphine)palladium(0) (Pd(PPh3)4) (11.5 g, 0.10 mmol) and potassium carbonate (41.4 g, 300 mmol), 150 mL of ethanol, 150 mL of water and 300 mL of toluene were added to a flask and dissolved. The mixture was then refluxed and stirred at 120 ° C for 3 hours. After the reaction was completed, the organic layer was extracted with ethyl acetate, and then the residual moisture was removed with magnesium sulfate and dried, and the resulting product was purified by column chromatography to obtain compound 2 (29.7 g, yield: 79%).

[0146] Preparation of compound 3

[0147] Compound 2 (29.7g, 79mmol) and 400mL of dichloromethane are added to a flask and dissolved. Next, 33mL of triethylamine is added thereto, and stirred at 0°C for 10 minutes. Then 16mL of trifluoromethanesulfonic anhydride is slowly added to the flask, and stirred for 1 hour. After the completion of the reaction, the organic layer is extracted with ethyl acetate, and residual moisture is then removed and dried with magnesium sulfate, and the products therefrom is purified by column chromatography to obtain compound 3 (25g, yield: 62.7%).

[0148] Preparation of compound C-193

[0149] Compound 3 (25 g, 49 mmol), 5-phenyl-5,7-dihydroindole[2,3-b]carbazole (14.9 g, 45 mmol), tris(dibenzylideneacetone)dipalladium(0) (1.6 g, 2 mmol), 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (1.4 g, 4 mmol), sodium tert-butoxide (10 g, 112 mmol) and 245 mL of o-xylene were added to a flask and refluxed for 4 hours. After the reaction was completed, the organic layer was extracted with ethyl acetate after vacuum distillation, and then the residual moisture was removed with magnesium sulfate and dried, and the resulting product was purified by column chromatography to obtain compound C-193 (10 g, yield: 32%).

[0150] Compound MW Tg Melting point C-193 689.82 156℃ 298℃

[0151] [Example 2] Preparation of Compound C-196

[0152]

[0153] Preparation of compound B-1

[0154] 4-Bronaphthalene-2-ol (9 g, 40 mmol), bis(pinacolato)diboron (12.3 g, 48 mmol), bis(triphenylphosphine)palladium(II) dichloride (566 mg, 0.807 mmol), potassium acetate (7.9 g, 81 mmol) and 200 mL of 1,4-dioxane were added to a flask and dissolved, and then refluxed at 110° C. for 3 hours. After the reaction was completed, the organic layer was extracted with ethyl acetate after vacuum distillation, and then residual moisture was removed with magnesium sulfate and dried, and the resulting product was purified by column chromatography to obtain compound B-1 (9.1 g, yield: 83%).

[0155] Preparation of compound B-2

[0156] Compound B-1 (9.1 g, 34 mmol), 2-chloro-4,6-diphenyl-1,3,5-triazine (10.8 g, 40 mmol), tetrakis(triphenylphosphine)palladium(0) (1.9 g, 2 mmol), potassium carbonate (13.9 g, 101 mmol), 50 mL of ethanol, 50 mL of water, and 100 mL of toluene were added to a flask and dissolved, and then refluxed at 120° C. for 3 hours. After the reaction was completed, the organic layer was extracted with ethyl acetate after vacuum distillation, and then residual moisture was removed with magnesium sulfate and dried, and the resulting product was purified by column chromatography to obtain compound B-2 (8 g, yield: 63%).

[0157] Preparation of compound B-3

[0158] Compound B-2 (8.5 g, 23 mmol) and 113 mL of dichloromethane were added to a flask and dissolved. Next, 9.5 mL of triethylamine was added thereto and stirred at 0° C. for 10 minutes. 7.4 mL of trifluoromethanesulfonic anhydride was then slowly added to the flask and stirred for 1 hour. After the reaction was complete, the organic layer was extracted with ethyl acetate, residual moisture was then removed and dried with magnesium sulfate, and the product obtained was purified by column chromatography to obtain compound B-3 (5.9 g, yield: 51%).

[0159] Preparation of compound C-196

[0160] Compound B-3 (5.9 g, 12 mmol), 5-phenyl-5,7-dihydroindole[2,3-b]carbazole (3 g, 9 mmol), tris(dibenzylideneacetone)dipalladium(0) (0.329 g, 0.361 mmol), 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (0.297 g, 0.729 mmol), sodium tert-butoxide (1.7 g, 112 mmol) and 361 mL of o-xylene were added to a flask and refluxed for 3 hours. After the reaction was completed, the organic layer was extracted with ethyl acetate after vacuum distillation, and then the residual moisture was removed with magnesium sulfate and dried, and the resulting product was purified by column chromatography to obtain compound C-196 (1.7 g, yield: 27%).

[0161] Compound MW Tg Melting point C-196 689.82 154.6℃ 262℃

[0162] [Example 3] Preparation of Compound C-9

[0163] Compound B-3 (9.6 g, 19.5 mmol), 12-phenyl-5,12-dihydroindole [3,2-a] carbazole (6.3 g, 19.5 mmol), tris (dibenzylideneacetone) dipalladium (0) (0.7 g, 0.78 mmol), 2-dicyclohexylphosphino-2', 6'-dimethoxybiphenyl (0.6 g, 1.5 mmol), sodium tert-butoxide (4.5 g, 48.8 mmol) and 97.5 mL of o-xylene were added to a flask and refluxed for 3 hours. After the reaction was completed, the organic layer was extracted with ethyl acetate after vacuum distillation, and then the residual moisture was removed with magnesium sulfate and dried, and the resulting product was purified by column chromatography to obtain compound C-9 (1 g, yield: 7.6%).

[0164] Compound MW Tg Melting point C-9 689.82 159.68℃ 307℃

[0165] Device Example 1: Production of an OLED device comprising a red-emitting organic electroluminescent compound according to the present disclosure

[0166] OLED devices were produced by using the organic electroluminescent compounds disclosed herein. First, a transparent electrode indium tin oxide (ITO) film (10Ω / sq) on a glass substrate for an OLED device (GEOMATEC CO., LTD., Japan) was ultrasonically cleaned sequentially with acetone, ethanol, and distilled water, and then stored in isopropyl alcohol. The ITO substrate was then mounted on a substrate holder of a vacuum vapor deposition device. Compound HI-1 was introduced into a chamber of a vacuum vapor deposition device, and the pressure in the chamber of the device was then controlled to 10 -7After that, an electric current is applied to the chamber to evaporate the above-introduced materials, thereby forming a first hole injection layer with a thickness of 80nm on the ITO substrate. Next, compound HI-2 is introduced into another chamber of a vacuum vapor deposition device, and the compound is evaporated by applying an electric current to the chamber, thereby forming a second hole injection layer with a thickness of 5nm on the first hole injection layer. Compound HT-1 is then introduced into another chamber of a vacuum vapor deposition device, and the compound is evaporated by applying an electric current to the chamber, thereby forming a first hole transport layer with a thickness of 10nm on the second hole injection layer. Compound HT-2 is then introduced into another chamber of a vacuum vapor deposition device, and the compound is evaporated by applying an electric current to the chamber, thereby forming a second hole transport layer with a thickness of 60nm on the first hole transport layer. After the hole injection layer and the hole transport layer are formed, a light-emitting layer is formed thereon as follows: compound C-193 is introduced into a chamber of a vacuum vapor deposition device as a host, and compound D-39 is introduced into another chamber as a dopant. The dopant was deposited in an amount of 3 wt% based on the total amount of the host and the dopant to form a light-emitting layer having a thickness of 40 nm on the second hole transport layer. Next, the compounds ETL-1 and EIL-1 were evaporated and deposited in a 50:50 weight ratio to form an electron transport layer having a thickness of 35 nm on the light-emitting layer. After the compound EIL-1 was deposited as an electron injection layer having a thickness of 2 nm on the electron transport layer, an Al cathode having a thickness of 80 nm was deposited on the electron injection layer by another vacuum vapor deposition device. Thus, an OLED device was produced. Each compound was deposited at 10 -6 It was purified by under-pressure vacuum sublimation and then used.

[0167] Device Example 2: Production of an OLED device comprising a red-emitting organic electroluminescent compound according to the present disclosure

[0168] An OLED device was produced in the same manner as in Device Example 1, except that Compound C-196 was used as a host material of the light-emitting layer.

[0169] Device Example 3: Production of an OLED device comprising a red-emitting organic electroluminescent compound according to the present disclosure

[0170] An OLED device was produced in the same manner as in Device Example 1, except that Compound C-9 was used as a host material of the light-emitting layer.

[0171] Comparative Example 1: Production of an OLED device not containing the red-emitting organic electroluminescent compound according to the present disclosure

[0172] An OLED device was produced in the same manner as in Device Example 1, except that Compound H-1 was used as a host material of the light-emitting layer.

[0173] Comparative Example 2: Production of an OLED device not containing the red-emitting organic electroluminescent compound according to the present disclosure

[0174] An OLED device was produced in the same manner as in Device Example 1, except that Compound H-2 was used as a host material of the light-emitting layer.

[0175] Comparative Example 3: Production of an OLED device not containing the red-emitting organic electroluminescent compound according to the present disclosure

[0176] An OLED device was produced in the same manner as in Device Example 1, except that Compound H-3 was used as a host material of the light-emitting layer.

[0177] Comparative Example 4: Production of an OLED device not containing the red-emitting organic electroluminescent compound according to the present disclosure

[0178] An OLED device was produced in the same manner as in Device Example 1, except that Compound H-4 was used as a host material of the light-emitting layer.

[0179] The compounds used in Device Examples 1 to 3 and Comparative Examples 1 to 4 are shown in Table 1 below.

[0180] Table 1

[0181]

[0182]

[0183] Evaluation: Organic Electroluminescent Devices

[0184] Lifespan characteristic measurement

[0185] The driving voltage and luminescent color of the organic electroluminescent devices produced in Device Examples 1 to 3 and Comparative Examples 1 to 4 at a brightness of 1,000 nits, and the time taken for light emission to decrease from 100% to 95% at a brightness of 5,000 nits (lifetime; T95) were measured and shown in Table 2 below.

[0186] Table 2

[0187]

[0188] Referring to Table 2 above, it was confirmed that the organic electroluminescent devices according to Device Examples 1 to 3 had significantly improved lifespan characteristics compared to Comparative Examples 1 to 4. As described above, by asymmetrically linking the indolocarbazole and the nitrogen-containing aromatic hexagonal ring group on the naphthalene linker, the donor-acceptor electron bonding of the compound in the excited state was weakened due to the destruction of electron conjugation, and the compound had a high HOMO energy level, thereby relatively improving the hole current characteristics compared to the comparative examples.

[0189] In addition, the host compound included in the comparative example has a fast electron current characteristic but a very slow hole current characteristic, resulting in a reduced lifespan due to charge imbalance; however, the organic electroluminescent compound according to one embodiment includes an asymmetric connection within its structure, and thus can improve charge balance due to the enhancement of hole conduction characteristics, thereby contributing to improved device characteristics.

[0190] In other words, devices using the organic electroluminescent compound according to the present disclosure as a host material for emitting light exhibit improved lifespan characteristics, and thus may have advantages in devices requiring long lifespan, such as flexible displays, white organic light-emitting devices, lighting equipment, and automotive displays.

Claims

1. An organic electroluminescent compound represented by any one of the following formulas 5 and 7: in, X1 to X3 each independently represent N; Ar1 to Ar3 each independently represent a deuterium-substituted or unsubstituted (C6-C30) aryl group; R1 to R3 each independently represent hydrogen, deuterium, halogen, cyano, carboxyl, nitro or hydroxyl; a and b each independently represent an integer from 0 to 4, c represents an integer from 0 to 2, when a or b is an integer of 2 or greater or c is 2, each R1, each R2 or each R3 may be the same or different; L1 is represented by any one of the following formulas R-1 to R-2: in, R4 represents hydrogen, deuterium, halogen, cyano, carboxyl, nitro or hydroxyl; d represents an integer from 0 to 6. When d is an integer of 2 or greater, each R4 may be the same or different; * indicates the connection position to the adjacent ring in Formula 1.

2. The organic electroluminescent compound according to claim 1, wherein Ar1 to Ar3 each independently represent a deuterium-substituted or unsubstituted (C6-C25) aryl group; R1 to R4 each independently represent hydrogen or deuterium.

3. The organic electroluminescent compound according to claim 1, wherein The compound represented by Formula 5 or 7 is selected from the following compounds: An organic electroluminescent material comprising the organic electroluminescent compound according to claim 1 . 5 . An organic electroluminescent device comprising the organic electroluminescent compound according to claim 1 .

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