WO2019235803A1

WO2019235803A1 - Organic electroluminescent compound and organic electroluminescent device comprising the same

Info

Publication number: WO2019235803A1
Application number: PCT/KR2019/006700
Authority: WO
Inventors: Hyun-Ju Kang; Hyo-Jung Lee; Sung-Wook Cho; Sang-Hee Cho
Original assignee: Rohm And Haas Electronic Materials Korea Ltd.
Priority date: 2018-06-05
Filing date: 2019-06-04
Publication date: 2019-12-12
Also published as: CN112119139A; KR20190138378A

Abstract

The present disclosure relates to an organic electroluminescent compound and an organic electroluminescent device comprising the same. By comprising the organic electroluminescent compound, an organic electroluminescent device having low driving voltage and/or a high luminous efficiency and/or long lifespan can be provided.

Description

ORGANIC ELECTROLUMINESCENT COMPOUND AND ORGANIC ELECTROLUMINESCENT DEVICE COMPRISING THE SAME

The present disclosure relates to an organic electroluminescent compound and an organic electroluminescent device comprising the same.

An electroluminescent device (EL device) is a self-light-emitting display device which has advantages in that it provides a wider viewing angle, a greater 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 aluminum complexes as materials for forming a light-emitting layer [Appl. Phys. Lett. 51, 913, 1987].

An organic EL device (OLED) changes electric energy into light by applying electricity to an organic electroluminescent material, and commonly comprises an anode, a cathode, and an organic layer formed between the two electrodes. The organic layer of the organic EL device may comprise a hole injection layer, a hole transport layer, a hole auxiliary layer, a light-emitting auxiliary layer, an electron blocking layer, a light-emitting layer (containing host and dopant materials), an electron buffer layer, a hole blocking layer, an electron transport layer, an electron injection layer, etc. In such organic EL device, holes from the anode and electrons from the cathode are injected into a light-emitting layer by the application of an electric voltage, and excitons having high energy are produced by the recombination of the holes and electrons. The organic light-emitting compound moves into an excited state by the energy and emits light from an energy when the organic light-emitting compound returns to the ground state from the excited state.

In conventional technology, 4,4’-N,N’-dicarbazol-biphenyl (CBP) is the most widely known phosphorescent host material. Although the conventional phosphorescent host materials provide good luminous characteristics, they have the following disadvantages: (1) Due to their low glass transition temperature and poor thermal stability, their degradation may occur during a high-temperature deposition process in a vacuum, and the lifespan of the device may be shortened. (2) The power efficiency of the organic electroluminescent device is given by [(π/voltage) × current efficiency], and the power efficiency is inversely proportional to the voltage. Although the organic electroluminescent device comprising phosphorescent host materials provides higher current efficiency (cd/A) than one comprising fluorescent materials, a significantly high driving voltage is necessary. Thus, there is no merit in terms of power efficiency (lm/W). (3) Also, the operational lifespan of the organic electroluminescent device is short, and luminous efficiency is still necessary to improve. Accordingly, in order to realize the excellent characteristics of the organic EL device, the materials constituting the organic layer in the device, in particular, the host or dopant constituting the light-emitting material, sholud be appropriately selected.

Korean Patent No. 2014-0006708 A discloses an organic electroluminescent device using a compound as a green phosphorescent host material in that a pyridine, pyrimidine or triazine is linked to an indolocarbazole derivative using at least one naphthylene as a linker.

Korean Patent Nos. 2013-0057397 A and 2016-0131963 A disclose a heterocyclic compound which can be used as a host material for a light-emitting layer; however, they do not disclose a host compound having an indolocarbazole derivative as a basic skeleton.

The object of the present disclosure is firstly, to provide an organic electroluminescent compound which is able to produce an organic electroluminescent device having low driving voltage and/or high luminous efficiency, and/or long lifespan, and secondly, to provide an organic electroluminescent device comprising the organic electroluminescent compound.

As a result of intensive studies to solve the technical problem above, the present inventors found that the aforementioned objective can be achieved by the organic electroluminescent compound represented by the following formula 1, so that the present invention was completed.

In formula 1,

A ring is tri- or more cyclic ring;

Ar1 and Ar2 each independently represent hydrogen, deuterium, cyano, a substituted or unsubstituted (C1-C30)alkyl, a substituted or unsubstituted (C6-C30)aryl, a substituted or unsubstituted (3- to 30-membered)heteroaryl, or a substituted or unsubstituted (C3-C30)cycloalkyl;

L₁ and L₂ each independently represent a single bond, a substituted or unsubstituted (C1-C30)alkylene, a substituted or unsubstituted (C6-C30)arylene, a substituted or unsubstituted (3- to 30-membered)heteroarylene, or a substituted or unsubstituted (C3-C30)cycloalkylene;

R₁ to R₃ each independently represent hydrogen, deuterium, halogen, cyano, a substituted or unsubstituted (C1-C30)alkyl, a substituted or unsubstituted (C6-C30)aryl, a substituted or unsubstituted (3- to 30-membered)heteroaryl, a substituted or unsubstituted (C3-C30)cycloalkyl, a substituted or unsubstituted (C1-C30)alkoxy, a substituted or unsubstituted tri(C1-C30)alkylsilyl, a substituted or unsubstituted di(C1-C30)alkyl(C6-C30)arylsilyl, a substituted or unsubstituted (C1-C30)alkyldi(C6-C30)arylsilyl, a substituted or unsubstituted tri(C6-C30)arylsilyl, a substituted or unsubstituted mono- or di- (C1-C30)alkylamino, a substituted or unsubstituted mono- or di- (C6-C30)arylamino, or a substituted or unsubstituted (C1-C30)alkyl(C6-C30)arylamino; or may be linked to adjacent substituents to form a substituted or unsubstituted ring;

a represents an integer of 1 to 4;

b represents an integer of 1 or more;

c represents an integer of 1 or 2; and

when a to c are 2 or more, each of R₁, each of R₂, or each of R₃ may be the same or different.

By using the organic electroluminescent compound according to the present disclosure, an organic electroluminescent device having a low driving voltage and/or a high luminous efficiency and/or long lifespan can be prepared.

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

The present disclosure relates to an organic electroluminescent compound represented by formula 1 and an organic electroluminescent device comprising the organic electroluminescent compound.

The term "organic electroluminescent compound" in the present disclosure means a compound that may be used in an organic electroluminescent device, and may be comprised in any material layer constituting an organic electroluminescent device, as necessary.

The term "organic electroluminescent material" in the present disclosure means a material that may be used in an organic electroluminescent device, and may comprise at least one compound. The organic electroluminescent material may be comprised in any layer constituting an organic electroluminescent device, as necessary. For example, the organic electroluminescent material may be a hole injection material, a hole transport material, a hole auxiliary material, a light-emitting auxiliary material, an electron blocking material, a light-emitting material, an electron buffer material, a hole blocking material, an electron transport material, or an electron injection material, etc.

Herein, "(C1-C30)alkyl(ene)" is meant to be a linear or branched alkyl having 1 to 30 carbon atoms constituting the chain, in which the number of carbon atoms is preferably 1 to 20, and more preferably 1 to 10. The above alkyl may include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, etc. "(C3-C30)cycloalkyl(ene)" is a mono- or polycyclic hydrocarbon having 3 to 30 ring backbone carbon atoms, in which the number of carbon atoms is preferably 3 to 20, and more preferably 3 to 7. The above cycloalkyl may include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc. "(C6-C30)aryl(ene)" is a monocyclic or fused ring radical derived from an aromatic hydrocarbon having 6 to 30 ring backbone carbon atoms, in which the number of the ring backbone carbon atoms is preferably 6 to 20, more preferably 6 to 15, may be partially saturated, and may comprise a spiro structure. Examples of the aryl specifically include phenyl, biphenyl, terphenyl, quaterphenyl, naphthyl, binaphthyl, phenylnaphthyl, naphthylphenyl, fluorenyl, phenylfluorenyl, dimethylfluorenyl, diphenylfluorenyl, benzofluorenyl, diphenylbenzofluorenyl, dibenzofluorenyl, phenanthrenyl, benzophenanthrenyl, phenylphenanthrenyl, anthracenyl, benzanthracenyl, indenyl, triphenylenyl, pyrenyl, tetracenyl, perylenyl, chrysenyl, benzochrysenyl, naphthacenyl, fluoranthenyl, benzofluoranthenyl, tolyl, xylyl, mesityl, cumenyl, spiro[fluorene-fluorene]yl, spiro[fluorene-benzofluorene]yl, azulenyl, etc. More specifically, the aryl may be o-tolyl, m-tolyl, p-tolyl, 2,3-xylyl, 3,4-xylyl, 2,5-xylyl, mesityl, o-cumenyl, m-cumenyl, p-cumenyl, p-t-butylphenyl, p-(2-phenylpropyl)phenyl, 4'-methylbiphenyl, 4"-t-butyl-p-terphenyl-4-yl, o-biphenyl, m-biphenyl, p-biphenyl, o-terphenyl, m-terphenyl-4-yl, m-terphenyl-3-yl, m-terphenyl-2-yl, p-terphenyl-4-yl, p-terphenyl-3-yl, p-terphenyl-2-yl, m-quaterphenyl, 1-naphthyl, 2-naphthyl, 1-fluorenyl, 2-fluorenyl, 3-fluorenyl, 4-fluorenyl, 9-fluorenyl, 9,9-dimethyl-1-fluorenyl, 9,9-dimethyl-2-fluorenyl, 9,9-dimethyl-3-fluorenyl, 9,9-dimethyl-4-fluorenyl, 9,9-diphenyl-1-fluorenyl, 9,9-diphenyl-2-fluorenyl, 9,9-diphenyl-3-fluorenyl, 9,9-diphenyl-4-fluorenyl, 1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl, 4-phenanthryl, 9-phenanthryl, 1-chrysenyl, 2-chrysenyl, 3-chrysenyl, 4-chrysenyl, 5-chrysenyl, 6-chrysenyl, benzo[c]phenanthryl, benzo[g]chrysenyl, 1-triphenylenyl, 2-triphenylenyl, 3-triphenylenyl, 4-triphenylenyl, 3-fluoranthenyl, 4-fluoranthenyl, 8-fluoranthenyl, 9-fluoranthenyl, benzofluoranthenyl, etc. "(3- to 30-membered)heteroaryl(ene)" is an aryl having 3 to 30 ring backbone atoms, in which the number of ring backbone atoms is preferably 5 to 25, including at least one, preferably 1 to 4 heteroatoms selected from the group consisting of B, N, O, S, Si, P, and Ge. The above heteroaryl may be a monocyclic ring, or a fused ring condensed with at least one benzene ring; and may be partially saturated. The above heteroatom may be linked with at least one substituent selected from the group consisting of hydrogen, deuterium, halogen, cyano, a substituted or unsubstituted (C1-C30)alkyl, a substituted or unsubstituted (C6-C30)aryl, a substituted or unsubstituted (5- to 30-membered)heteroaryl, a substituted or unsubstituted (C3-C30)cycloalkyl, a substituted or unsubstituted (C1-C30)alkoxy, a substituted or unsubstituted tri(C1-C30)alkylsilyl, a substituted or unsubstituted di(C1-C30)alkyl(C6-C30)arylsilyl, a substituted or unsubstituted (C1-C30)alkyldi(C6-C30)arylsilyl, a substituted or unsubstituted tri(C6-C30)arylsilyl, a substituted or unsubstituted mono- or di- (C1-C30)alkylamino, a substituted or unsubstituted mono- or di- (C6-C30)arylamino, and a substituted or unsubstituted (C1-C30)alkyl(C6-30)arylamino. Also, the above heteroaryl may be one formed by linking at least one heteroaryl or aryl group to a heteroaryl group via a single bond(s); and may comprise a spiro structure. Examples of the heteroaryl specifically may include a monocyclic ring-type heteroaryl including furyl, thiophenyl, pyrrolyl, imidazolyl, pyrazolyl, thiazolyl, thiadiazolyl, isothiazolyl, isoxazolyl, oxazolyl, oxadiazolyl, triazinyl, tetrazinyl, triazolyl, tetrazolyl, furazanyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, etc., and a fused ring-type heteroaryl including benzofuranyl, benzothiophenyl, isobenzofuranyl, dibenzofuranyl, dibenzothiophenyl, benzoimidazolyl, benzothiazolyl, benzoisothiazolyl, benzoisoxazolyl, benzoxazolyl, imidazopyridinyl, isoindolyl, indolyl, benzoindolyl, indazolyl, benzothiadiazolyl, quinolyl, isoquinolyl, cinnolinyl, quinazolinyl, quinoxalinyl, carbazolyl, azacarbazolyl, benzocarbazolyl, dibenzocarbazolyl, phenoxazinyl, phenanthridinyl, benzodioxolyl, indolizidinyl, acrylidinyl, silafluorenyl, germafluorenyl, etc. More specifically, the heteroaryl may be 1-pyrrolyl, 2-pyrrolyl, 3-pyrrolyl, 2-pyridinyl, 3-pyridinyl, 4-pyridinyl, 2-pyrimidinyl, 4-pyrimidinyl, 5-pyrimidinyl, 6-pyrimidinyl, 1,2,3-triazin-4-yl, 1,2,4-triazin-3-yl, 1,3,5-triazin-2-yl, 1-imidazolyl, 2-imidazolyl, 1-pyrazolyl, 1-indolizidinyl, 2-indolizidinyl, 3-indolizidinyl, 5-indolizidinyl, 6-indolizidinyl, 7-indolizidinyl, 8-indolizidinyl, 2-imidazopyridinyl, 3-imidazopyridinyl, 5-imidazopyridinyl, 6-imidazopyridinyl, 7-imidazopyridinyl, 8-imidazopyridinyl, 1-indolyl, 2-indolyl, 3-indolyl, 4-indolyl, 5-indolyl, 6-indolyl, 7-indolyl, 1-isoindolyl, 2-isoindolyl, 3-isoindolyl, 4-isoindolyl, 5-isoindolyl, 6-isoindolyl, 7-isoindolyl, 2-furyl, 3-furyl, 2-benzofuranyl, 3-benzofuranyl, 4-benzofuranyl, 5-benzofuranyl, 6-benzofuranyl, 7-benzofuranyl, 1-isobenzofuranyl, 3-isobenzofuranyl, 4-isobenzofuranyl, 5-isobenzofuranyl, 6-isobenzofuranyl, 7-isobenzofuranyl, 2-quinolyl, 3-quinolyl, 4-quinolyl, 5-quinolyl, 6-quinolyl, 7-quinolyl, 8-quinolyl, 1-isoquinolyl, 3-isoquinolyl, 4-isoquinolyl, 5-isoquinolyl, 6-isoquinolyl, 7-isoquinolyl, 8-isoquinolyl, 2-quinoxalinyl, 5-quinoxalinyl, 6-quinoxalinyl, 1-carbazolyl, 2-carbazolyl, 3-carbazolyl, 4-carbazolyl, 9-carbazolyl, azacarbazole-1-yl, azacarbazole-2-yl, azacarbazole-3-yl, azacarbazole-4-yl, azacarbazole-5-yl, azacarbazole-6-yl, azacarbazole-7-yl, azacarbazole-8-yl, azacarbazole-9-yl, 1-phenanthridinyl, 2-phenanthridinyl, 3-phenanthridinyl, 4-phenanthridinyl, 6-phenanthridinyl, 7-phenanthridinyl , 8-phenanthridinyl, 9-phenanthridinyl, 10-phenanthridinyl, 1-acrylidinyl, 2-acrylidinyl, 3-acrylidinyl, 4-acrylidinyl, 9-acrylidinyl, 2-oxazolyl, 4-oxazolyl, 5-oxazolyl, 2-oxadiazolyl, 5-oxadiazolyl, 3-furazanyl, 2-thienyl, 3-thienyl, 2-methylpyrrole-1-yl, 2-methylpyrrole-3-yl, 2-methylpyrrole-4-yl, 2-methylpyrrole-5-yl, 3-methylpyrrole-1-yl, 3-methylpyrrole-2-yl, 3-methylpyrrole-4-yl, 3-methylpyrrole-5-yl, 2-t-butylpyrrole-4-yl, 3-(2-phenylpropyl)pyrrole-1-yl, 2-methyl-1-indolyl, 4-methyl-1-indolyl, 2-methyl-3-indolyl, 4-methyl-3-indolyl, 2-t-butyl-1-indolyl, 4-t-butyl-1-indolyl, 2-t-butyl-3-indolyl, 4-t-butyl-3-indolyl, 1-dibenzofuranyl, 2-dibenzofuranyl, 3-dibenzofuranyl, 4-dibenzofuranyl, 1-dibenzothiophenyl, 2-dibenzothiophenyl, 3-dibenzothiophenyl, 4-dibenzothiophenyl, 1-silafluorenyl, 2-silafluorenyl, 3-silafluorenyl, 4-silafluorenyl, 1-germafluorenyl, 2-germafluorenyl, 3-germafluorenyl, and 4-germafluorenyl, etc.

"Nitrogen-containing (5- to 30-membered)heteroaryl(ene)" is meant to be an aryl group having at least one N, and 5 to 30 ring backbone atoms, in which the number of ring backbone atoms is preferably 5 to 20, more preferably 5 to 15; having preferably 1 to 4 heteroatoms, and may be a monocyclic ring, or a fused ring condensed with at least one benzene ring; may be partially saturated. Also, the above nitrogen-containing heteroaryl may be one formed by linking at least one heteroaryl or aryl group to a heteroaryl group via a single bond(s); and includes a monocyclic ring-type heteroaryl including pyrrolyl, imidazolyl, pyrazolyl, triazinyl, tetrazinyl, triazolyl, tetrazolyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, etc., and a fused ring-type heteroaryl including benzimidazolyl, isoindolyl, indolyl, indazolyl, benzothiadiazolyl, quinolyl, isoquinolyl, cinnolinyl, quinazolinyl, quinoxalinyl, benzoquinoxalinyl, carbazolyl, phenanthridinyl, etc. "Halogen" includes F, Cl, Br, and I.

In addition, "ortho (o)," "meta (m)," and "para (p)" are meant to signify the substitution position of all substituents. Ortho position is a compound with substituents, which are adjacent to each other, e.g., at the 1 and 2 positions on benzene. Meta position is the next substitution position of the immediately adjacent substitution position, e.g., a compound with substituents at the 1 and 3 positions on benzene. Para position is the next substitution position of the meta position, e.g., a compound with substituents at the 1 and 4 positions on benzene.

Herein, "a substituted or unsubstituted ring formed in linked to an adjacent substituent" means a substituted or unsubstituted (C3-C30) mono- or polycyclic, alicyclic, aromatic ring, or a combination thereof, formed by linking or fusing two or more adjacent substituents; preferably, may be a substituted or unsubstituted (C5-C25) mono- or polycyclic, alicyclic, aromatic ring, or a combination thereof; more preferably, may be a substituted or unsubstituted (C5-C18) mono- or polycyclic, alicyclic, aromatic ring, or a combination thereof. In addition, at least one of the carbon atoms in the formed ring may be replaced with at least one heteroatom selected from the group consisting of B, N, O, S, Si, and P, preferably, N, O, and S. According to one embodiment, the ring formed in linking to an adjacent substituent may be a (C5-C20) polycyclic aromatic ring, which may contain at least one heteroatom selected from the group consisting of N, O, and S.

In addition, "substituted" in the expression "substituted or unsubstituted" means that a hydrogen atom in a certain functional group is replaced with another atom or functional group, i.e., a substituent. The substituents of the substituted (C1-C30)alkyl(ene), the substituted (C6-C30)aryl(ene), the substituted (3- to 30-membered)heteroaryl(ene), the substituted (C3-C30)cycloalkyl(ene), the substituted (C1-C30)alkoxy, the substituted tri(C1-C30)alkylsilyl, the substituted di(C1-C30)alkyl(C6-C30)arylsilyl, the substituted (C1-C30)alkyldi(C6-C30)arylsilyl, the substituted tri(C6-C30)arylsilyl, the substituted mono- or di- (C1-C30)alkylamino, the substituted mono- or di- (C6-C30)arylamino, the substituted (C1-C30)alkyl(C6-C30)arylamino, and the substituted ring in Ar1, Ar2, L₁, L₂, and R₁ to R₃, are each independently at least one selected from the group consisting of deuterium, halogen, cyano, carboxyl, nitro, hydroxyl, (C1-C30)alkyl, halo(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 (3- to 30-membered)heteroaryl, (3- 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)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)ar(C1-C30)alkyl, and (C1-C30)alkyl(C6-C30)aryl, e.g., the substituents may be an unsubstituted phenyl, an unsubstituted o-biphenyl, an unsubstituted m-biphenyl, an unsubstituted p-biphenyl, or an unsubstituted naphthyl.

Hereinafter, the organic electroluminescent compound according to one embodiment will be described.

The organic electroluminescent compound according to one embodiment is represented by the following formula 1.

In formula 1,

A ring is a tri- or more cyclic ring;

a represents an integer of 1 to 4;

b represents an integer of 1 or more;

c represents an integer of 1 or 2; and

The organic electroluminescent compound of formula 1 according to one embodiment may be comprised in the light-emitting layer of an organic electroluminescent device as host materials.

The organic electroluminescent compound of formula 1 according to one embodiment has a basic skeleton in which an electron withdrawing group (EWG) having high electron withdrawing ability such as an aryl group and/or a nitrogen-containing heteroaryl group is bonded to an indolocarbazole derivative.

In general, indolocarbazole can be formed as various structures according to the linking position of a carbazole moiety and is suitable to use in a hole transport host due to high HOMO (Highest Occupied Molecular Orbital) energy level. The organic electroluminescent compound of formula 1 is a structure in which nitrogen (N) of indolocarbazole is bonded in a specific direction, i.e., to face in the same direction; and an indolocarbazole condensed with at least one benzene ring at its terminal, as a basic skeleton; a nitrogen(s) (N) of indolocarbazole is bonded to an aryl group having a strong electron characteristic and/or a nitrogen-containing heteroaryl group, thereby the entire molecule thereof has bipolar characteristics. Due to this, the bonding force between the hole and the electron can be increased, so that the compound of the present disclosure can exhibit excellent characteristics as a host material of the light-emitting layer; and as a result, an organic electroluminescent device having a low driving voltage and/or a high luminous efficiency and/or long lifespan can be provided.

Further, the structure in which at least one benzene ring is condensed with the indolocarbazole moiety enhances the thermal stability of the device due to increasing the conjugation length while maintaining the properties of the material, thereby improving the lifespan characteristics.

In one embodiment, in formula 1, A ring is a tri- or more cyclic ring, e.g., may be tricyclic to pentacyclic ring. Preferably, A ring may be a tri- or more cyclic aryl ring, more preferably, a condensed ring condensed with at least three benzene rings. For example, A ring may be a substituted or unsubstituted phenanthrene, or a substituted or unsubstituted phenalene.

The organic electroluminescent compound according to one embodiment may be represented by any one of the following formulae 1-1 to 1-3, as a basic skeleton in which at least one benzene ring is condensed with indolo[2,3-b]carbazole moiety.

In formulae 1-1 to 1-3, Ar1, Ar2, L₁, L₂, R₁ to R₃, a and c are defined as formula 1;

R₄ and R₅ each independently represent, hydrogen, deuterium, halogen, cyano, a substituted or unsubstituted (C1-C30)alkyl, a substituted or unsubstituted (C6-C30)aryl, a substituted or unsubstituted (3- to 30-membered)heteroaryl, a substituted or unsubstituted (C3-C30)cycloalkyl, a substituted or unsubstituted (C1-C30)alkoxy, a substituted or unsubstituted tri(C1-C30)alkylsilyl, a substituted or unsubstituted di(C1-C30)alkyl(C6-C30)arylsilyl, a substituted or unsubstituted (C1-C30)alkyldi(C6-C30)arylsilyl, a substituted or unsubstituted tri(C6-C30)arylsilyl, a substituted or unsubstituted mono- or di- (C1-C30)alkylamino, a substituted or unsubstituted mono- or di- (C6-C30)arylamino, or a substituted or unsubstituted (C1-C30)alkyl(C6-C30)arylamino; or may be linked to adjacent substituents to form a substituted or unsubstituted ring;

b represents an integer of 1 to 6;

d and e each independently are defined as a; and

when b, d, and e are an integer of 2 or more, each of R₂, each of R₄, or each of R₅ may be the same or different.

In one embodiment, in formulae 1 and 1-1 to 1-3, Ar1 and Ar2 each independently represent hydrogen, deuterium, cyano, a substituted or unsubstituted (C1-C30)alkyl, a substituted or unsubstituted (C6-C30)aryl, a substituted or unsubstituted (3- to 30-membered)heteroaryl, or a substituted or unsubstituted (C3-C30)cycloalkyl, preferably, each independently may be hydrogen, a substituted or unsubstituted (C6-C18)aryl or a substituted or unsubstituted (3- to 18-membered)heteroaryl, more preferably, each independently may be hydrogen, a substituted or unsubstituted (C6-C12)aryl, or a substituted or unsubstituted nitrogen-containing (5- to 20-membered) heteroaryl. For example, Ar1 and Ar2 each independently may be hydrogen, a substituted or unsubstituted phenyl, a substituted or unsubstituted o-biphenyl, a substituted or unsubstituted m-biphenyl, a substituted or unsubstituted p-biphenyl, a substituted or unsubstituted naphthyl, a substituted or unsubstituted triphenyl, a substituted or unsubstituted triazinyl, a substituted or unsubstituted quinoxalinyl, a substituted or unsubstituted quinazolinyl, or a substituted or unsubstituted benzoquinoxalinyl.

In formulae 1 and 1-1 to 1-3 according to one embodiment, a nitrogen(s) of indolocarbazole moiety is(are) bonded to an aryl group having a strong electron characteristic and/or a nitrogen-containing heteroaryl group; preferably at least one nitrogen of indolocarbazole moiety may be bonded to a nitrogen-containing heteroaryl group. In the indolocarbazole derivatives having high hole-transporting property, the selection of substituents having a suitable electron-transporting property is important since the band gap, electrical characteristics, interface characteristics, etc., may be changed according to the type of substituent and the bonding position.

Wherein in one embodiment, Ar1 and Ar2 each independently may be a nitrogen-containing heteroaryl selected from the following formulae 2-1 and 2-2. Thereby, the lifespan of an organic electroluminescent device comprising the organic electroluminescent compound according to one embodiment can be improved.

In formulae 2-1 and 2-2,

X each independently represents N or CR₂₁;

R₁₁ and R₂₁ each independently represent hydrogen, deuterium, cyano, a substituted or unsubstituted (C1-C30)alkyl, a substituted or unsubstituted (C6-C30)aryl, or a substituted or unsubstituted (3- to 30-membered)heteroaryl; or may be linked to adjacent substituents to form a substituted or unsubstituted ring; and

n represents an integer of 1 to 4.

In one embodiment, in formulae 2-1 and 2-2, at least one X may be N, for example, at least two X may be N. Specifically, Ar1 or Ar2 represented by formula 2-1 may be a substituted or unsubstituted triazinyl, Ar1 or Ar2 represented by formula 2-2 may be a substituted or unsubstituted naphthyl, a substituted or unsubstituted quinoxalinyl, a substituted or unsubstituted quinazolinyl, or a substituted or unsubstituted benzoquinoxalinyl.

In one embodiment, in formulae 1 and 1-1 to 1-3, L₁ and L₂ each independently represent, a single bond, a substituted or unsubstituted (C1-C30)alkylene, a substituted or unsubstituted (C6-C30)arylene, a substituted or unsubstituted (3- to 30-membered)heteroarylene, or a substituted or unsubstituted (C3-C30)cycloalkylene, preferably, each independently may be a single bond, a substituted or unsubstituted (C6-C18)arylene, or a substituted or unsubstituted (3- to 18-membered)heteroarylene, more preferably, each independently may be a single bond, a substituted or unsubstituted (C6-C12)arylene, or a substituted or unsubstituted nitrogen-containing (5- to 20-membered)heteroarylene. For example, L₁ and L₂ each independently may be a single bond, a substituted or unsubstituted phenylene, a substituted or unsubstituted o-biphenylene, a substituted or unsubstituted m-biphenylene, a substituted or unsubstituted p-biphenylene, a substituted or unsubstituted naphthylenylene, a substituted or unsubstituted triphenylene, a substituted or unsubstituted triazinylene, a substituted or unsubstituted quinoxalinylene, a substituted or unsubstituted quinazolinylene, or a substituted or unsubstituted benzoquinoxalinylene.

In one embodiment, in formulae 1 and 1-1 to 1-3, R₁ to R₅ each independently represent hydrogen, deuterium, halogen, cyano, a substituted or unsubstituted (C1-C30)alkyl, a substituted or unsubstituted (C6-C30)aryl, a substituted or unsubstituted (3- to 30-membered)heteroaryl, a substituted or unsubstituted (C3-C30)cycloalkyl, a substituted or unsubstituted (C1-C30)alkoxy, a substituted or unsubstituted tri(C1-C30)alkylsilyl, a substituted or unsubstituted di(C1-C30)alkyl(C6-C30) arylsilyl, a substituted or unsubstituted (C1-C30)alkyldi(C6-C30)arylsilyl, a substituted or unsubstituted tri(C6-C30)arylsilyl, a substituted or unsubstituted mono- or di- (C1-C30)alkylamino, a substituted or unsubstituted mono- or di- (C6-C30)arylamino, or a substituted or unsubstituted (C1-C30)alkyl(C6-C30)arylamino; or may be linked to adjacent substituents to form a substituted or unsubstituted ring. Preferably, R₁ to R₅ each independently may be hydrogen, deuterium, halogen, cyano, a substituted or unsubstituted (C1-C10)alkyl, a substituted or unsubstituted (C3-C10)cycloalkyl, or a substituted or unsubstituted (C1-C10)alkoxy, more preferably, may be hydrogen, deuterium, halogen, cyano, or a substituted or unsubstituted (C1-C4)alkyl. For example, all of R₁ to R₅ may be hydrogen.

In one embodiment, in formula 1, a represents an integer of 1 to 4, c represents an integer of 1 or 2. In addition, b represents an integer of 1 or more, preferably may be an integer of 1 to 20, or an integer of 1 to 14, more preferably, may be an integer of 1 to 8, or an integer of 1 to 6.

In one embodiment, in formulae 1-1 to 1-3, b may be an integer of 1 to 6, d and e each independently may be an integer of 1 to 4.

In one embodiment, in formulae 1-1 to 1-3, at least one of L₁, L₂, Ar1, and Ar2 may be a substituted or unsubstituted nitrogen-containing (5- to 30-membered)heteroaryl(ene), preferably, a substituted or unsubstituted nitrogen-containing (5- to 20-membered)heteroaryl(ene), more preferably, a substituted or unsubstituted nitrogen-containing (5- to 15-membered)heteroaryl(ene).

In one embodiment, in formulae 1-1 to 1-3, Ar1 and Ar2 each independently may be hydrogen, a substituted or unsubstituted (C6-C30)aryl, or a substituted or unsubstituted (3- to 30-membered)heteroaryl; L₁ and L₂ each independently may be a single bond, a substituted or unsubstituted (C6-C30)arylene, or a substituted or unsubstituted (3- to 30-membered)heteroarylene; preferably, Ar1 and Ar2 each independently may be hydrogen, a substituted or unsubstituted (C6-C18)aryl, or a substituted or unsubstituted (3- to 18-membered)heteroaryl; L₁ and L₂ each independently may be a single bond, a substituted or unsubstituted (C6-C18)arylene, or a substituted or unsubstituted (3- to 18-membered)heteroarylene; more preferably, Ar1 and Ar2 each independently may be hydrogen, a substituted or unsubstituted (C6-C12)aryl, or a substituted or unsubstituted nitrogen-containing (5- to 20-membered)heteroaryl; L₁ and L₂ each independently may be a single bond, a substituted or unsubstituted (C6-C12)arylene, or a substituted or unsubstituted nitrogen-containing (5- to 20-membered)heteroarylene.

In one embodiment, in formulae 1-1 to 1-3, L₁ may be a single bond or a substituted or unsubstituted nitrogen-containing (5- to 20-membered)heteroarylene; Ar1 may be hydrogen, a substituted or unsubstituted (C6-C18)aryl, or a substituted or unsubstituted nitrogen-containing (5- to 20-membered)heteroaryl; L₂ may be a single bond or a substituted or unsubstituted (C6-C18)arylene; and Ar2 may be hydrogen or a substituted or unsubstituted (C6-C18)aryl.

According to one embodiment, the compound represented by formula 1 may be more specifically illustrated by the following compounds, but is not limited thereto:

The compound of formula 1 according to the present disclosure may be produced by a synthetic method known to a person skilled in the art, and for example referring to the following reaction scheme 1, but is not limited thereto:

[Reaction Scheme 1]

In reaction scheme 1, A, Ar₁, Ar₂, L₁, and L₂ are as defined in formula 1.

As described above, exemplary synthesis examples of the compounds represented by formula 1 according to one embodiment are described, but they are based on Buchwald-Hartwig cross coupling reaction, N-arylation reaction, H-mont-mediated etherification reaction, Miyaura borylation reaction, Suzuki cross-coupling reaction, Intramolecular acid-induced cyclization reaction, Pd(II)-catalyzed oxidative cyclization reaction, Grignard reaction, Heck reaction, Cyclic Dehydration reaction, SN₁ substitution reaction, SN₂ substitution reaction, Phosphine-mediated reductive cyclization reaction, etc. It will be understood by one skilled in the art that the above reaction proceeds even if other substituents defined in the formula 1 other than the substituents described in the specific synthesis examples are bonded.

According to one embodiment, the present disclosure provides an organic electroluminescent device comprising the organic electroluminescent compound of formula 1.

The organic electroluminescent device according to the present disclosure includes a first electrode; a second electrode; and at least one organic layer interposed between the first electrode and the second electrode. The organic layer may comprise at least one of the organic electroluminescent compound of formula 1. The organic layer may further comprise at least one compound selected from the group consisting of an arylamine-based compound and a styrylarylamine-based compound. Also, the organic layer may further comprise at least one metal selected from the group consisting of metals of Group 1, metals of Group 2, transition metals of the 4^th period, transition metals of the 5^th period, lanthanides, and organic metals of the d-transition elements of the Periodic Table, or at least one complex compound comprising such a metal.

An organic electroluminescent material according to one embodiment may be used as light-emitting materials for a white organic light-emitting device. The white organic light-emitting device has suggested various structures such as a parallel side-by-side arrangement method, a stacking arrangement method, or CCM (color conversion material) method, etc., according to the arrangement of R (Red), G (Green), B (blue), or YG (yellowish green) light-emitting units. In addition, the organic electroluminescent material according to one embodiment may also be applied to the organic electroluminescent device comprising a QD (quantum dot).

Specifically, one of the first electrode and the second electrode may be an anode and the other may be a cathode. Wherein, the first electrode and the second electrode may each be formed as a transmissive conductive material, a transflective conductive material, or a reflective conductive material. The organic electroluminescent device may be a top emission type, a bottom emission type, or a both-sides emission type according to the kinds of the material forming the first electrode and the second electrode. The organic layer may comprise a light-emitting layer, and may further comprise 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 interlayer, a hole blocking layer, an electron blocking layer, and an electron buffer layer.

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 may be multi-layers in order to lower 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 multi-layers may use two compounds simultaneously. Also, the hole injection layer may be doped as a p-dopant. Also, the electron blocking layer may be placed between the hole transport layer (or hole injection layer) and the light-emitting layer, and can confine the excitons within the light-emitting layer by blocking the overflow of electrons from the light-emitting layer to prevent a light-emitting leakage. The hole transport layer or the electron blocking layer may be multi-layers, and wherein each layer may use a plurality of compounds.

An electron buffer layer, a hole blocking layer, an electron transport layer, an electron injection layer, or a combination thereof can be used between the light-emitting layer and the cathode. The electron buffer layer may be multi-layers in order to control the injection of the electron and improve the interfacial properties between the light-emitting layer and the electron injection layer, wherein each of the multi-layers may use two compounds simultaneously. The hole blocking layer or the electron transport layer may also be multi-layers, wherein each layer may use a plurality of compounds. Also, the electron injection layer may be doped as an n-dopant.

The light-emitting auxiliary layer may be placed between the anode and the light-emitting layer, or between the cathode and the light-emitting layer. When the light-emitting auxiliary layer is placed between the anode and the light-emitting layer, it can be used for promoting the hole injection and/or the hole transport, or for preventing the overflow of electrons. When the light-emitting auxiliary layer is placed between the cathode and the light-emitting layer, it can be used for promoting the electron injection and/or the electron transport, or for preventing the overflow of holes. In addition, the hole auxiliary layer may be placed between the hole transport layer (or hole injection layer) and the light-emitting layer, and may be effective to promote or block the hole transport rate (or the hole injection rate), thereby enabling the charge balance to be controlled. When an organic electroluminescent device includes two or more hole transport layers, the hole transport layer, which is further included, may be used as the hole auxiliary layer or the electron blocking layer. The light-emitting auxiliary layer, the hole auxiliary layer, or the electron blocking layer may have an effect of improving the efficiency and/or the lifespan of the organic electroluminescent device.

In the organic electroluminescent device of the present disclosure, preferably, at least one layer (hereinafter, "a surface layer") selected from a chalcogenide layer, a halogenated metal layer, and a metal oxide layer may be placed on an inner surface(s) of one or both electrode(s). Specifically, a chalcogenide (including oxides) layer of silicon and aluminum is preferably placed on an anode surface of an electroluminescent medium layer, and a halogenated metal layer or a metal oxide layer is preferably placed on a cathode surface of an electroluminescent medium layer. The operation stability for the organic electroluminescent device may be obtained by the surface layer. Preferably, the chalcogenide includes SiO_X(1≤X≤2), AlO_X(1≤X≤1.5), SiON, SiAlON, etc.; the halogenated metal includes LiF, MgF₂, CaF₂, a rare earth metal fluoride, etc.; and the metal oxide includes Cs₂O, Li₂O, MgO, SrO, BaO, CaO, etc.

In the organic electroluminescent device of the present disclosure, 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 may be placed on at least one surface of a pair of electrodes. In this case, the electron transport compound is reduced to an anion, and thus it becomes easier to inject and transport electrons from the mixed region to an electroluminescent medium. Furthermore, the hole transport compound is oxidized to a cation, 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. A reductive dopant layer may be employed as a charge generating layer to prepare an organic electroluminescent device having two or more light-emitting layers and emitting white light.

The organic electroluminescent compound of formula 1 may be comprised in the light-emitting layer. When used in the light-emitting layer, the organic electroluminescent compound of formula 1 may be comprised as a host material. Preferably, the light-emitting layer may further contain at least one dopant, and if necessary, may further contain a compound other than the organic electroluminescent compound of formula 1 of the present disclosure as a second host material. Herein, the weight ratio of the first host material to the second host material is in the range of 1:99 to 99:1. The second host material may use any well-known phosphorescent host.

The dopant comprised in the organic electroluminescent material of the present disclosure may be at least one phosphorescent or fluorescent dopant, preferably a phosphorescent dopant. The phosphorescent dopant material applied to the organic electroluminescent device of the present disclosure is not particulary limited, but may be preferably a metallated complex compound(s) of a metal atom(s) selected from iridium (Ir), osmium (Os), copper (Cu), and platinum (Pt), more preferably an ortho-metallated complex compound(s) of a metal atom(s) selected from iridium (Ir), osmium (Os), copper (Cu), and platinum (Pt), and even more preferably ortho-metallated iridium complex compound(s).

The compound represented by the following formula 101 may be used as the dopant, but is not limited thereto:

In formula 101,

wherein, L is selected from the following structure 1 or 2:

R₁₀₀ to R₁₀₃ each independently represent hydrogen, deuterium, halogen, halogen-substituted or unsubstituted (C1-C30)alkyl, a substituted or unsubstituted (C3-C30)cycloalkyl, a substituted or unsubstituted (C6-C30)aryl, cyano, a substituted or unsubstituted (3- to 30-membered)heteroaryl, or a substituted or unsubstituted (C1-C30)alkoxy; or R₁₀₀ to R₁₀₃ may be linked to an adjacent substituent(s) to form a substituted or unsubstituted fused ring, e.g., a substituted or unsubstituted quinoline, a substituted or unsubstituted benzofuropyridine, a substituted or unsubstituted benzothienopyridine, a substituted or unsubstituted indenopyridine, a substituted or unsubstituted benzofuroquinoline, a substituted or unsubstituted benzothienoquinoline, or a substituted or unsubstituted indenoquinoline;

R₁₀₄ to R₁₀₇ each independently represent hydrogen, deuterium, halogen, halogen-substituted or unsubstituted (C1-C30)alkyl, a substituted or unsubstituted (C3-C30)cycloalkyl, a substituted or unsubstituted (C6-C30)aryl, a substituted or unsubstituted (3- to 30-membered)heteroaryl, cyano, or a substituted or unsubstituted (C1-C30)alkoxy; or R₁₀₄ to R₁₀₇ may be linked to an adjacent substituent(s) to form a substituted or unsubstituted fused ring, e.g., a substituted or unsubstituted naphthyl, a substituted or unsubstituted fluorene, a substituted or unsubstituted dibenzothiophene, a substituted or unsubstituted dibenzofuran, a substituted or unsubstituted indenopyridine, a substituted or unsubstituted benzofuropyridine, or a substituted or unsubstituted benzothienopyridine;

R₂₀₁ to R₂₁₁ each independently represent hydrogen, deuterium, halogen, halogen-substituted or unsubstituted (C1-C30)alkyl, a substituted or unsubstituted (C3-C30)cycloalkyl, or a substituted or unsubstituted (C6-C30)aryl; or may be linked to an adjacent substituent(s) to form a substituted or unsubstituted fused ring; and

s represents an integer of 1 to 3.

The specific examples of the dopant compound include the following, but are not limited thereto:

In order to form each layer of the organic electroluminescent device of the present disclosure, dry film-forming methods such as vacuum evaporation, sputtering, plasma, ion plating methods, etc., or wet film-forming methods such as ink jet printing, nozzle printing, slot coating, spin coating, dip coating, flow coating methods, etc., can be used. When forming a layer by the dopant and the host compounds of the present disclosure, co-evaporation or mixture-evaporation may be used, but is not limited thereto.

When using a wet film-forming method, a thin film may be formed by dissolving or diffusing materials forming each layer into any suitable solvent such as ethanol, chloroform, tetrahydrofuran, dioxane, etc. The solvent may be any solvent where the materials forming each layer can be dissolved or diffused, and where there are no problems in film-formation capability.

The co-deposition is a mixed deposition method in which two or more isomer materials are put into respective individual crucible sources and a current is applied to both cells simultaneously to evaporate the materials and to perform mixed deposition; and the mixed deposition is a mixed deposition method in which two or more isomer materials are mixed in one crucible source before deposition, and then a current is applied to one cell to evaporate the materials.

The organic electroluminescent device of the present disclosure can be used for the manufacture of display devices such as smartphones, tablets, notebooks, PCs, TVs, or display devices for vehicles, or lighting devices such as outdoor or indoor lighting.

Hereinafter, the preparation method of compounds and the properties thereof according to the present disclosure will be explained with reference to the representative compound or the intermediate compound of the present disclosure in order to understand the present disclosure in detail.

[Example 1] Preparation of compound H-1

Preparation of Compound 1-1

9-bromophenanthrene (50 g, 194.4 mmol) was dissolved in 1300 mL of THF (Tetrahydrofuran) in flask, and at -78℃, n- butyllithium (97 mL, 194.4 mmol, 2.0 M in Hexane) was added slowly to the flask. After one hour, triisopropylborate (89 mL, 388.8 mmol) was added to the flask and stirred at room temperature for 12 hours, and then distilled water was added. After completion of the reaction, the organic layer was extracted with ethylacetate, and the residual water was removed with magnesium sulfate followed by drying, and then distillation under reduced pressure. Next, compound 1-1 was obtained (33.9 g, yield: 78%) by recrystallization with ethyl acetate and hexane.

Preparation of Compound 1-2

Compound 1-1 (33.9 g, 152.66 mmol), 1,4-dibromo-2-nitrobenzene (35.7 g, 128.22 mmol), tetrakistriphenylphosphine palladium (0) (7.4 g, 63.61 mmol), sodium carbonate (40 g, 381.66 mmol), 600 mL of toluene, 200 mL of ethanol, and 200 mL of water were added to a flask and then refluxed with stirring for 5 hours. After completion of the reaction, the organic layer was extracted with ethylacetate, and the residual water was removed with magnesium sulfate followed by drying, and thereafter purified by column chromatography to obtain compound 1-2 (34 g, yield: 71%).

Preparation of Compound 1-3

Compound 1-2 (34 g, 89.89 mmol), triphenylphosphine (58 g, 224.73 mmol), and 450 mL of dichlorobenzene were added to a flask and dissolved, followed by refluxing at 200℃ for 24 hours. After completion of the reaction, the solvent was removed by distillation under reduced pressure, and thereafter purified by column chromatography to obtain compound 1-3 (22 g, yield: 70%).

Preparation of Compound 1-4

Compound 1-3 (20 g, 57.76 mmol), 2-chloroaniline (12 mL, 115.53 mmol), tris (dibenzylideneacetone)dipalladium(0) (1.59 g, 1.732 mmol), tri-tert-butylphosphine (1.7 mL, 3.462 mmol), sodium-tert-butoxide (16.6 g, 173.28 mmol), and 300 mL of toluene were added to a flsk and refluxed with stirring for 5 hours. After completion of the reaction, the organic layer was extracted with ethylacetate, and the residual water was removed with magnesium sulfate followed by drying, and thereafter purified by column chromatography to obtain compound 1-4 (15 g, yield: 68%).

Preparation of Compound 1-5

Compound 1-4 (14 g, 35.63 mmol), iodobenzene (6 mL, 53.45 mmol), copper iodide (3.4 g, 17.81 mmol), 1,2-diaminohexane (4 g, 35.63 mmol), cesium carbonate (23.2 g, 71.26 mmol), and 180 mL of xylene were added to a flask and refluxed with stirring for 24 hours. After completion of the reaction, the organic layer was extracted with ethylacetate, and the residual water was removed with magnesium sulfate followed by drying, and thereafter purified by column chromatography to obtain compound 1-5 (15.5 g, yield: 92%).

Preparation of Compound 1-6

Compound 1-5 (15.5 g, 33.05 mmol), palladium(II) acetate (1.5 g, 6.610 mmol), tricyclohexylphosphine tetrafluoroborate (3.6 g, 9.915 mmol), cesium carbonate (32 g, 99.15 mmol), and 165 mL of dimethylaminopyridine were added to a flask and refluxed with stirring for 1 hour. After completion of the reaction, the organic layer was extracted with ethylacetate, and the residual water was removed with magnesium sulfate followed by drying, and thereafter purified by column chromatography to obtain compound 1-6 (3.2 g, yield: 22%).

Preparation of Compound H-1

Compound 1-6 (3.2 g, 33.05 mmol), 2-chloro-3-phenylquinoxaline (2.1 g, 8.877 mmol), potassium carbonate (1 g, 7.398 mmol), and 40 mL of dimethylaminopyridine were added to a flask and refluxed with stirring for 24 hours. After completion of the reaction, the organic layer was extracted with ethylacetate, and the residual water was removed with magnesium sulfate followed by drying, and thereafter purified by column chromatography to obtain compound H-1 (1.5g, yield: 32%).

[Example 2] Preparation of compound H-56

Preparation of Compound H-56

Compound 1-6 (4 g, 9.24 mmol), 2-chloro-4,6-diphenyl-1,3,5-triazine (3.7 g, 10.17 mmol), potassium carbonate (1.3 g, 9.24 mmol), 4-dimethylpyridine(0.5 g, 4.62 mmol), and 50 mL of dimethylformaldehyde were added to a flask and refluxed with stirring for 24 hours. After completion of the reaction, the organic layer was extracted with ethylacetate, and the residual water was removed with magnesium sulfate followed by drying, and thereafter purified by column chromatography to obtain compound H-56 (1.3 g, yield: 22%).

Hereinafter, the preparation method and the properties of an organic electroluminescent device comprising the organic electroluminescent compound of the present disclosure will be explained in order to understand the present disclosure in detail.

[Device Examples 1 and 2] Producing an OLED in which the compound

according to the present disclosure is deposited as a host

An OLED device comprising the compound of the present disclosure was produced. First, a transparent electrode indium tin oxide (ITO) thin film (10 Ω/sq) on a glass substrate for an OLED device (GEOMATEC CO., LTD., Japan) was subjected to an ultrasonic washing with acetone, ethanol, and distilled water, sequentially, and then was stored in isopropanol. The ITO substrate was then mounted on a substrate holder of a vacuum vapor deposition apparatus. Compound HI-1 was introduced into a cell of the vacuum vapor deposition apparatus, and then the pressure in the chamber of the apparatus was controlled to 10^-6 torr. Thereafter, an electric current was applied to the cell to evaporate the above-introduced material, thereby forming a first hole injection layer having a thickness of 80 nm on the ITO substrate. Next, compound HI-2 was introduced into another cell of the vacuum vapor deposition apparatus, and was evaporated by applying an electric current to the cell, thereby forming a second hole injection layer having a thickness of 5 nm on the first hole injection layer. Compound HT-1 was then introduced into another cell of the vacuum vapor deposition apparatus, and was evaporated by applying an electric current to the cell, thereby forming a first hole transport layer having a thickness of 10 nm on the second hole injection layer. Compound HT-2 was then introduced into another cell of the vacuum vapor deposition apparatus, and was evaporated by applying an electric current to the cell, thereby forming a second hole transport layer having a thickness of 60 nm on the first hole transport layer. After forming the hole injection layers and the hole transport layers, a light-emitting layer was formed thereon as follows: Compound H-1 (Device Example 1) or H-56 (Device Example 2) of the following Table 1 was introduced into one cell of the vacuum vapor depositing apparatus as a host, and compound D-39 was introduced into another cell as a dopant. The two host materials were evaporated at a different rate and the dopant was deposited in a doping amount of 3 wt%, to form a light-emitting layer having a thickness of 40 nm on the hole transport layer. Next, compounds ET-1 and EI-1 were evaporated at a rate of 1:1, and were deposited to form an electron transport layer having a thickness of 35 nm on the light-emitting layer. After depositing compound EI-1 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 apparatus. Thus, an OLED was produced.

[Comparative Examples 1 and 2] Producing an OLED in which the

conventional compound is deposited as a host

OLEDs were produced in the same manner as in Device Example 1, except that compound CBP (Comparative Example 1) or compound X (Comparative Example 2) was used as the host of the light-emitting layer, respectively.

The compounds used in Device Examples 1 and 2, and Comparative Examples 1 and 2 are shown specifically in Table 1 below.

Evaluation: Characteristics Evaluation of an Organic Electroluminescent

Device

The results of the driving voltage, the efficiency, the color coordinates at a luminance of 5,000 nits, and the time taken to reduce from 100% to 95% at a luminance of 5,000 nit (lifespan; T95), of the organic electroluminescent device of Device Examples 1 and 2 and Comparative Examples 1 and 2 produced as described above, are shown in the following Table 2.

Referring to Table 2 above, the OLEDs of Device Examples 1 and 2 using the organic electroluminescent compound according to one embodiment as a host, exhibit far superior effects in terms of driving voltage, luminous efficiency, and lifespan, as compared with the OLED of Comparative Example 1 using a conventional host material such as CBP.

In addition, it was confirmed that the OLED of Comparative Example 2 uses compound X having indolocarbazole derivatives as a basic skeleton; however, it is significantly lower than the OLED according to the Device Examples in terms of luminous efficiency and lifespan. The compound X is indolo[2,3-a]carbazole as a basic skeleton, wherein as the N-N distance of indolocarbazole is nearer, the electron mobility is slowed due to the steric hindrance between LUMO and the phenyl ring of phenanthrene fused to its terminal, resulting in a decrease in the efficiency and lifespan of the device.

That is, from the Device Examples and Comparative Examples, it can be confirmed that the organic electroluminescent device comprising the organic electroluminescent compound according to the present disclosure has low driving voltage, high luminous efficiency, and significantly improved lifespan characteristics as compared with the organic electroluminescent device comprising the conventional organic electroluminescent compound.

Claims

An organic electroluminescent compound represented by the following formula 1:

wherein,

A ring is a tri- or more cyclic ring;

Ar1 and Ar2 each independently represent hydrogen, deuterium, cyano, a substituted or unsubstituted (C1-C30)alkyl, a substituted or unsubstituted (C6-C30)aryl, a substituted or unsubstituted (3- to 30-membered)heteroaryl, or a substituted or unsubstituted (C3-C30)cycloalkyl;

L₁ and L₂ each independently represent a single bond, a substituted or unsubstituted (C1-C30)alkylene, a substituted or unsubstituted (C6-C30)arylene, a substituted or unsubstituted (3- to 30-membered)heteroarylene, or a substituted or unsubstituted (C3-C30)cycloalkylene;

R₁ to R₃ each independently represent hydrogen, deuterium, halogen, cyano, a substituted or unsubstituted (C1-C30)alkyl, a substituted or unsubstituted (C6-C30)aryl, a substituted or unsubstituted (3- to 30-membered)heteroaryl, a substituted or unsubstituted (C3-C30)cycloalkyl, a substituted or unsubstituted (C1-C30)alkoxy, a substituted or unsubstituted tri(C1-C30)alkylsilyl, a substituted or unsubstituted di(C1-C30)alkyl(C6-C30)arylsilyl, a substituted or unsubstituted (C1-C30)alkyldi(C6-C30)arylsilyl, a substituted or unsubstituted tri(C6-C30)arylsilyl, a substituted or unsubstituted mono- or di- (C1-C30)alkylamino, a substituted or unsubstituted mono- or di- (C6-C30)arylamino, or a substituted or unsubstituted (C1-C30)alkyl(C6-C30)arylamino; or may be linked to adjacent substituents to form a substituted or unsubstituted ring;

a represents an integer of 1 to 4;

b represents an integer of 1 or more;

c represents an integer of 1 or 2; and

when a to c are 2 or more, each of R₁, each of R₂, or each of R₃ may be the same or different.
The organic electroluminescent compound according to claim 1, wherein the formula 1 is represented by any one of the following formulae 1-1 to 1-3:

wherein,

Ar1, Ar2, L₁, L₂, R₁ to R₃, a and c are as defined in claim 1;

b represents an integer of 1 to 6;

R₄ and R₅ each independently, are as defined in R₁ to R₃;

d and e each independently, are as defined in a; and

when b, d, and e are 2 or more, each of R₂, each of R₄, or each of R₅ may be the same or different.
The organic electroluminescent compound according to claim 1, Ar1 and Ar2 each independently, are selected from the following formulae 2-1 and 2-2:

wherein,

X each independently represents N or CR₂₁;

R₁₁ and R₂₁ each independently represent hydrogen, deuterium, cyano, a substituted or unsubstituted (C1-C30)alkyl, a substituted or unsubstituted (C6-C30)aryl, or a substituted or unsubstituted (3- to 30-membered)heteroaryl; or may be linked to adjacent substituents to form a substituted or unsubstituted ring; and

n represents an integer of 1 to 4.
The organic electroluminescent compound according to claim 1, wherein the substituents of the substituted (C1-C30)alkyl(ene), the substituted (C6-C30)aryl(ene), the substituted (3- to 30-membered)heteroaryl(ene), the substituted (C3-C30)cycloalkyl(ene), the substituted (C1-C30)alkoxy, the substituted tri(C1-C30)alkylsilyl, the substituted di(C1-C30)alkyl(C6-C30)arylsilyl, the substituted (C1-C30)alkyldi(C6-C30)arylsilyl, the substituted tri(C6-C30)arylsilyl, the substituted mono- or di- (C1-C30)alkylamino, the substituted mono- or di- (C6-C30)arylamino, the substituted (C1-C30)alkyl(C6-C30)arylamino, and the substituted ring in Ar1, Ar2, L₁, L₂, and R₁ to R₃ each independently represent at least one selected from the group consisting of deuterium, halogen, cyano, carboxyl, nitro, hydroxyl, (C1-C30)alkyl, halo(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 (3- to 30-membered)heteroaryl, (3- 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)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)ar(C1-C30)alkyl, and (C1-C30)alkyl(C6-C30)aryl.
The organic electroluminescent compound according to claim 1, wherein the compound represented by formula 1 is selected from the group consisting of:
An organic electroluminescent device comprising the organic electroluminescent compound according to claim 1.
The organic electroluminescent device according to claim 6, wherein the organic electroluminescent compound is contained in a light-emitting layer.