ORGANIC ELECTROLUMINESCENT MATERIALS AND ORGANIC ELECTROLUMINESCENT DEVICE COMPRISING THE SAME

Abstract

The present disclosure relates to an organic electroluminescent device including a first electrode; a second electrode; and at least one light-emitting layer(s) positioned between the first electrode and the second electrode, and wherein the light-emitting layer includes a host comprising a compound represented by formula 1 and a compound represented by formula 2, and a dopant comprising a compound represented by formula 3, so that the present disclosure may provide an organic electroluminescent device having high efficiency and long lifespan property.

Description

TECHNICAL FIELD

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

BACKGROUND ART

An organic electroluminescent device (OLED) was first 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].

The light-emitting material of an OLED is the most important factor determining luminous efficiency of the device, and may be classified into a host material and a dopant material in a functional aspect. A light-emitting material can be used by mixing a host and a dopant in order to improve color purity, luminous efficiency, and stability. Generally, a device having excellent electroluminescent (EL) characteristics has a structure comprising a light-emitting layer formed by doping a dopant to a host. When using such a dopant/host material system as a light-emitting material, their selection is important since host materials greatly influence the efficiency and lifespan of the light-emitting device.

Recently, an urgent task is the development of an OLED having high efficiency and long lifespan property. In particular, the development of highly excellent light-emitting material over conventional light-emitting materials is urgently required, considering the EL properties necessary for medium and large-sized OLED panels.

DISCLOSURE OF THE INVENTION

Technical Problem

The object of the present disclosure is firstly, to provide organic electroluminescent materials which are able to produce an organic electroluminescent device having high luminous efficiency and long lifespan property, and secondly, is to provide an organic electroluminescent device comprising an organic electroluminescent material.

Solution to Problems

As a result of intensive studies to solve the technical problem above, the present inventors found that the aforementioned objective can be achieved by an organic electroluminescent device including a host material comprising a compound represented by the following formula 1 and a compound represented by the following formula 2, and a dopant material comprising a compound represented by the following formula 3, in a light-emitting layer, so that the present invention was completed.

in formula 1,

La represents a single bond or a substituted or unsubstituted (C6-C30)arylene;

Ma represents a substituted or unsubstituted (5- to 30-membered)heteroaryl containing nitrogen; and

Xa to Xh each independently represent, hydrogen, deuterium, halogen, cyano, a substituted or unsubstituted (C1-C30)alkyl, a substituted or unsubstituted (C2-C30)alkenyl, a substituted or unsubstituted (C2-C30)alkynyl, a substituted or unsubstituted (C3-C30)cycloalkyl, a substituted or unsubstituted (C6-C30)aryl, a substituted or unsubstituted (3- to 30-membered)heteroaryl, a substituted or unsubstituted tri(C1-C30)alkylsilyl, a substituted or unsubstituted tri(C6-C30)arylsilyl, a substituted or unsubstituted di(C1-C30)alkyl(C6-C30)arylsilyl, or a substituted or unsubstituted mono- or di- (C6-C30)arylamino; or may be linked to the adjacent substituents to form a ring(s);

in formula 2,

A₁ and A₂ each independently represent, a substituted or unsubstituted (C6-C30)aryl, a substituted or unsubstituted dibenzofuranyl, a substituted or unsubstituted dibenzothiophenyl, or a substituted or unsubstituted carbazolyl; and

X₁₁ to X₂₆ each independently represent, hydrogen, deuterium, a substituted or unsubstituted (C6-C30)aryl, or a substituted or unsubstituted (3- to 30-membered)heteroaryl; or may be linked to the adjacent substituents to form a ring(s);

provided that at least four of X₁₁ to X₂₆ are deuterium, and at least one of X_11, X₁₈, X₁₉, and X₂₆ is deuterium;

in formula 3,

R₁ to R₈ each independently represent, hydrogen, deuterium, halogen, (C1-C30)alkyl unsubstituted or substituted with deuterium and/or (C3-C30)cycloalkyl, 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 may be linked to the adjacent substituents to form a ring(s); and

R₉ to R₁₁ each independently represent, hydrogen, deuterium, halogen, (C1-C30)alkyl unsubstituted or substituted with deuterium, a substituted or unsubstituted (C3-C30)cycloalkyl, or a substituted or unsubstituted (C6-C30)aryl; or may be linked to the adjacent substituents to form a ring(s).

Advantageous Effects of Invention

By using an organic electroluminescent material according to the present disclosure, an organic electroluminescent device having a high luminous efficiency and long lifespan property can be provided.

EMBODIMENTS OF THE INVENTION

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 material and an organic electroluminescent device comprising the same, and wherein the organic electroluminescent material includes host materials and dopant materials.

The present disclosure relates to an organic electroluminescent device including a first electrode; a second electrode; and at least one light-emitting layer(s) positioned between the first electrode and the second electrode, wherein the light-emitting layer includes a host comprising a compound represented by formula 1 and a compound represented by formula 2, and a dopant comprising a compound represented by formula 3.

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.

Herein, the term “organic electroluminescent material” 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 (containing host and dopant materials), an electron buffer material, a hole blocking material, an electron transport material, or an electron injection material, etc.

The term “a plurality of organic electroluminescent materials” in the present disclosure means an organic electroluminescent material comprising a combination of at least two compounds, which may be comprised in any layer constituting an organic electroluminescent device. It may mean both a material before being comprised in an organic electroluminescent device (for example, before vapor deposition) and a material after being comprised in an organic electroluminescent device (for example, after vapor deposition). For example, a plurality of organic electroluminescent materials may be a combination of at least two compounds, which may be comprised in at least one layer of 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, an electron buffer layer, a hole blocking layer, an electron transport layer, and an electron injection layer. Such at least two compounds may be comprised in the same layer or in different layers, and may be mixture-evaporated or co-evaporated, or may be individually evaporated.

Herein, the term “a plurality of host materials” means an organic electroluminescent material comprising a combination of at least two host materials. It may mean both a material before being comprised in an organic electroluminescent device (e.g., before vapor deposition) and a material after being comprised in an organic electroluminescent device (e.g., after vapor deposition). A plurality of host materials of the present disclosure may be comprised in any light-emitting layer constituting an organic electroluminescent device. The at least two compounds comprised in a plurality of host materials may be comprised together in one light-emitting layer, or may each be comprised in separate light-emitting layers. When at least two compounds are comprised in one light-emitting layer, the at least two compounds may be mixture-evaporated to form a layer or may be individually and simultaneously co-evaporated to form a layer.

Herein, “(C1-C30)alkyl” 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, sec-butyl, etc. Herein, the term “(C3-C30)cycloalkyl” is meant to be 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, cyclopentylmethyl, cyclohexylmethyl, etc. Herein, “(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 include a spiro structure. Examples of the aryl specifically may be 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[fluoren-fluoren]yl, spiro[fluoren-benzofluoren]yl, azulenyl, tetramethyl-dihydrophenanthrenyl, 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, 11,11-dimethyl-1-benzo[a]fluorenyl, 11,11-dimethyl-2-benzo[a]fluorenyl, 11,11-dimethyl-3-benzo[a]fluorenyl, 11,11 -dimethyl-4-benzo[a]fluorenyi, 11,11-dimethyl-5-benzo[a]fluorenyl, 11,11-dimethyl-6-benzo[aJfluorenyl, 11,11-dimethyl-7-benzo[a]fluorenyl, 11,11-dimethyl-8-benzo[a]fluorenyl, 11,11-dimethyl-9-benzo[a]fluorenyl, 11,11-dimethyl-10-benzo[a]fluorenyl, 11,11-dimethyl-1-benzo[b]fluorenyl, 11,11-dimethyl-2-benzo[b]fluorenyl, 11,11-dimethyl-3-benzo[b]fluorenyl, 11, 11-dimethyl-4-benzo[b]fluorenyl, 11, 11-dimethyl-5-benzo[b]fluorenyl, 11, 11-dimethyl-6-benzo[b]fluorenyl, 11,11-dimethyl-7-benzo[b]fluorenyl, 11,11-dimethyl-8-benzo[b]fluorenyl, 11,11 -dimethyl-9-benzo[b]fluorenyl, 11,11-dimethyl-10-benzo[b]fluorenyl, 11,11–dimethyl-1–benzo[c]fluorenyl, 11,11-dimethyl-2-benzo[c]fluorenyl, 11,11-dimethyl-3-benzo[c]fluorenyl, 11, 11-dimethyl-4-benzo[c]fluorenyl, 11,11-dimethyl-5-benzo[c]fluorenyl, 11,11-dimethyl-6-benzo[c]fluorenyl, 11,11-dimethyl-7-benzo[c]fluorenyl, 11,11-dimethyl-8-benzo[c]fluorenyl, 11,11 -dimethyl-9-benzo[c]fluorenyl, 11,11-dimethyl-10-benzo[c]fluorenly, 11,11–diphenyl-1–benzo[a]fluorenyl, 11,11-diphenyl-2-benzo[a]fluorenyl, 11,11-diphenyl-3-benzo[a]fluorenyl, 11,11-diphenyi-4-benzo[a]fluorenyl, 11,11-diphenyl-5-benzo[a]fluorenyl, 11,11 -diphenyl-6-benzo[a]fluorenyl, 11,11-diphenyl-7-benzo[a]fluorenyl, 11,11-diphenyl-8-benzo[a]fluorenyl, 11,11-diphenyl-9-benzo[a]fluorenyl, 11,11-diphenyl-10-benzo[a]fluorenyl, 11,11 -diphenyl-1 -benzo[b]fluorenyl, 11,11-diphenyl-2-benzo[b]fluorenyl, 11, 11-diphenyl-3-benzo[b]fluorenyl, 11,11 -diphenyl-4-benzo[b]fluorenyl, 11,11-diphenyl-5-benzo[b]fluorenyl, 11,11-diphenyl-6-benzo[blfluorenyl, 11,11 -diphenyl-7-benzo[b]fluorenyl, 11,11 -diphenyl-8-benzo[b]fluorenyl, 11,11-diphenyl-9-berizo[b]fluorenyl, 11,11 -diphenyl-10-benzo[b]fluorenyl, 11, 11-diphenyl-1-benzo[c]fluorenyl, 11, 11-diphenyl-2-benzo[c]fluorenyl, 11,11-diphenyl-3-benzo[c]fluorenyl, 11,11-diphenyl-4-benzo[c]fluorenyl, 11,11-diphenyl-5-benzo[c]fluorenyl, 11,11-diphenyl-6-benzo[c]fluorenyl, 11,11-diphenyl-7-benzo[c]fluorenyl, 11,11-diphenyl-8-benzo[c]fluorenyi, 11,11 -diphenyi-9-benzo[c]fluorenyl, 11,11 -diphenyl-10-benzo[c]fluorenyl, 9,9,10,10-tetramethyl-9, 10-dihydro-1 -phenanthrenyl, 9,9,10,″1 0-tetramethyl-9,1 0-dihydro-2-phenanthrenyl, 9,9,10,10-tetramethyl-9,10-dihydro-3-phenanthrenyl, 9,9,10,10-tetramethyl-9,10-dihydro-4-phenanthrenyl, etc. Herein, “(3- to 30-membered)heteroaryl(ene)” is an aryl having 3 to 30 ring backbone atoms including at least one, preferably 1 to 4 heteroatoms selected from the group consisting of B, N, O, S, Si, P, Se, and Ge, in which the number of the ring backbone carbon atoms is preferably 3 to 30, and more preferably 5 to 20. The above heteroaryl(ene) may be a monocyclic ring, or a fused ring condensed with at least one benzene ring; and may be partially saturated. Also, the above heteroaryl or heteroarylene herein 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 be 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, dibenzoselenophenyl, benzofuroquinolinyl, benzofuroquinazolinyl, benzofuronaphthiridinyl, benzofuropyrimidinyl, naphthofuropyrimidinyl, benzothienoquinolinyl, benzothienoquinazolinyl, benzothienonaphthiridinyl, benzothienopyrimidinyl, naphthothienopyrimidinyl, pyrimidoindolyi, benzopyrimidoindolyl, benzofuropyrazinyl, naphthofuropyrazinyl, benzothienopyrazinyl, naphthothienopyrazinyl, pyrazinoindolyl, benzopyrazinoindolyl, benzoimidazolyl, benzothiazolyl, benzoisothiazolyl, benzoisoxazolyl, benzoxazolyl, imidazopyridinyl, isoindolyl, indolyl, benzoindolyl, indazolyl, benzothiadiazolyl, quinolyl, isoquinolyl, cinnolinyl, quinazolinyl, quinoxalinyl, carbazolyl, azacarbazolyl, benzocarbazolyl, dibenzocarbazolyl, phenoxazinyl, phenanthridinyl, benzodioxolyl, indolizidinyl, acridinyl, silafluorenyl, germafluorenyl, benzotriazolyl, phenazinyl, imidazopyridinyl, chromenoquinazolinyl, thiochromenoquinazolinyl, dimethylbenzopyrimidinyl, indolocarbazolyl, indenocarbazolyl, 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, azacarbazol-1-yl, azacarbazol-2-yl, azacarbazol-3-yl, azacarbazol-4-yl, azacarbazol-5-yl, azacarbazol-6-yl, azacarbazol-7-yl, azacarbazol-8-yl, azacarbazol-9-yl, 1-phenanthridinyl, 2-phenanthridinyl, 3-phenanthridinyl, 4-phenanthridinyl, 6-phenanthridinyl, 7-phenanthridinyl, 8-phenanthridinyl, 9-phenanthridinyl, 10-phenanthridiriyl, 1-acridinyl, 2-acridinyl, 3-acridinyl, 4-acridinyl, 9-acridinyl, 2-oxazolyl, 4-oxazolyl, 5-oxazolyl, 2-oxadiazolyl, 5-oxadiazolyl, 3-furazanyl, 2-thienyl, 3-thienyl, 2-methylpyrrol--1-yl, 2-methylpyrrol-3-yl, 2-methylpyrrol-4-yl, 2-methylpyrrol-5-yl, 3-methylpyrrol-1 -yl, 3-methylpyrrol-2-yl, 3-methylpyrrol-4-yl, 3-methylpyrrol-5-yl, 2-t-butylpyrrol-4-yl, 3-(2-phenylpropyl)pyrrol-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-naphtho-[1,2-b]-benzofuranyl, 2-naphtho-[1,2-b]-benzofuranyl, 3-naphtho-[1,2-b]-benzofuranyl, 4-naphtho-[1,2-b]-benzofuranyl, 5-naphtho-[1,2-b]-benzofuranyl, 6-naphtho-[1,2-b]-benzofuranyl, 7-naphtho-[1,2-b]-benzofuranyl, 8-naphtho-[1,2-b]-benzofuranyl, 9-naphtho-[″1,2-bJ-benzofuranyl, 10-naphtho-[1,2-b]-benzofuranyl, 1-naphtho-[2,3-b]-benzofuranyl, 2-naphtho-[2,3-b]-benzofuranyl, 3-naphtho-[2,3-b]-benzofuranyl, 4-naphtho-[2, 3-b]-benzofuranyl, 5-naphtho-[2,3-b]-benzofuranyl, 6-naphtho-[2,3-b]-benzofuranyl, 7-naphtho-[2,3-b]-benzofuranyl, 8-naphtho-[2,3-b]-benzofuranyl, 9-naphtho-[2,3-b]-benzofuranyl, 10-naphtho-[2,3-b]-benzofuranyl, 1-naphtho-[2,1-b]-benzofuranyl, 2-naphtho-[2,1-b]-benzofuranyl, 3-naphtho-[2,1-b]-benzofuranyl, 4-naphtho-[2,1-b]-benzofuranyl, 5-naphtho-[2,1-b]-benzofuranyl, 6-naphtho-[2,1-b]-benzofuranyl, 7-naphtho-[2,1-b]-benzofuranyl, 8-naphtho-[2,1-b]-benzofuranyl, 9-naphtho-[2,1-b]-benzofuranyl, 10-naphtho-[2,1-b]-benzofuranyl, 1-naphtho-[1,2-b]-benzothiophenyl, 2-naphtho-[1,2-b]-benzothiophenyl, 3-naphtho-[1,2-b]-benzothiophenyl, 4-naphtho-[1,2-b]-benzothiophenyl, 5-naphtho-[1,2-b]-benzothiophenyl, 6-naphtho-[1,2-b]-benzothiophenyl, 7-naphtho-[1,2-b]-benzothiophenyl, 8-naphtho-[1,2-b]-benzothiophenyl, 9-naphtho-[1,2-b]-benzothiophenyl, 10-naphtho-[1,2-b]-benzothiophenyl, 1-naphtho-[2,3-b]-benzothiophenyl, 2-naphtho-[2,3-b]-benzothiophenyl, 3-naphtho-[2,3-b]-benzothiophenyl, 4-naphtho-[2,3-b]-benzothiophenyl, 5-naphtho-[2,3-b]-benzothiophenyl, 1-naphtho-[2,1-b]-benzothiophenyl, 2-naphtho-[2,1-b]-benzothiophenyl, 3-naphtho-[2,1-b]-benzothiophenyl, 4-naphtho-[2,1-b]-benzothiophenyl, 5-naphtho-[2,1-b]-benzothiophenyl, 6-naphtho-[2,1-b]-benzothiophenyl, 7-naphtho-[2,″1-b]-benzothiophenyl, 8-naphtho-[2,1-b]-benzothiophenyl, 9-naphtho-[2,1-b]-benzothiophenyl, 10-naphtho-[2,1-b]-benzothiophenyl, 2-benzofuro[3,2-d]pyrimidinyl, 6-benzofuro[3,2-d]pyrimidinyl, 7-benzofuro[3,2-d]pyrimidinyl, 8-benzofuro[3,2-d]pyrimidinyl, 9-benzofuro[3,2-dJpyrimidinyl, 2-benzothio[3,2-d]pyrimidinyl, 6-benzothio[3,2-djpyrimidinyl, 7-benzothio[3,2-d]pyrimidinyl, 8-benzothio[3,2-d]pyrimidinyl, 9-benzothio[3,2-d]pyrimidinyl, 2-benzofuro[3,2-d]pyrazinyl, 6-benzofuro[3,2-d]pyrazinyl, 7-benzofuro[3,2-d]pyrazinyl, 8-benzofuro[3,2-d]pyrazinyl, 9-benzofuro[3,2-d]pyrazinyl, 2-benzothio[3,2-d]pyrazinyl, 6-benzothio[3,2-d]pyrazinyl, 7-benzothio[3,2-d]pyrazinyl, 8-benzothio[3,2-d]pyrazinyl, 9-benzothio[3,2-d]pyrazinyl, 1-silafluorenyl, 2-silafluorenyl, 3-silafluorenyl, 4-silafluorenyl, 1-germafluorenyl, 2-germafluorenyl, 3-germafluorenyl, 4-germafluorenyl, 1-dibenzoselenophenyl, 2-dibenzoselenophenyl, 3-dibenzoselenophenyl, 4-dibenzoselenophenyl, etc. Herein, the term “a fused ring of (C3-C30) aliphatic ring and (C6-C30) aromatic ring” means a ring formed by fusing at least one aliphatic ring having 3 to 30 ring backbone carbon atoms in which the carbon atoms number is preferably 3 to 25, more preferably 3 to 18, and at least one aromatic ring having 6 to 30 ring backbone carbon atoms in which the carbon atoms number is preferably 6 to 25, more preferably 6 to 18. For example, the fused ring may be a fused ring of at least one benzene and at least one cyclohexane, or a fused ring of at least one naphthalene and at least one cyclopentane, etc. Herein, the carbon atoms in the fused ring of (C3-C30) aliphatic ring and (C6-C30) aromatic ring may be replaced with at least one heteroatom selected from B, N, O, S, Si and P, preferably at least one heteroatom selected from N, O and S. The term “Halogen” in the present disclosure includes F, Cl, Br, and l.

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, the term “a ring formed in linking to an adjacent substituent” means a substituted or unsubstituted (3- to 30-membered) 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 (5- to 25-membered) mono- or polycyclic, alicyclic, aromatic ring, or a combination thereof. Further, the formed ring may include 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 of the present disclosure, the number of atoms in the ring skeleton is 5 to 20; according to another embodiment of the present disclosure, the number of atoms in the ring skeleton is 5 to 15. In one embodiment, the fused ring may be, for example, benzofuropyridine ring, benzothienopyridine ring, a substituted or unsubstituted dibenzothiophene ring, a substituted or unsubstituted dibenzofuran ring, a substituted or unsubstituted naphthalene ring, a substituted or unsubstituted phenanthrene ring, a substituted or unsubstituted fluorene ring, a substituted or unsubstituted benzofluorene ring, a substituted or unsubstituted benzothiophene ring, a substituted or unsubstituted benzofuran ring, a substituted or unsubstituted indole ring, a substituted or unsubstituted indene ring, a substituted or unsubstituted benzene ring, or a substituted or unsubstituted carbazole ring, etc.

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, and substituted with a group to which two or more substituents are connected among the substituents. For example, “a substituent to which two or more substituents are connected” may be pyridine-triazine. That is, pyridine-triazine may be heteroaryl or may be interpreted as one substituent in which two heteroaryls are connected. The substituents of the substituent alkyl, the substituent alkenyl, the substituent alkynyl, the substituent cycloalkyl, the substituent aryl(ene), the substituent heteroaryl, the substituent cycloalkyl, the substituent alkoxy, the substituent trialkylsilyl, the substituent dialkylarylsilyl, the substituent triarylsilyl, and the substituent diarylamino in the formulas of the present disclosure, each independently represent, at least one selected from the group consisting of deuterium; halogen; cyano; carboxyl; nitro; hydroxyl; phosphine oxide; (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; (3- to 30-membered)heteroaryl unsubstituted or substituted with (C6-C30)aryl; (C6-C30)aryl unsubstituted or substituted with (3- to 30-membered) heteroaryl; tri(C1-C30)alkylsilyl; tri(C6-C30)arylsilyl; di(C1-C30)alkyl(C6-C30)arylsilyl; (C1-C30)alkyldi(C6-C30)arylsilyl; a fused ring of (C3-C30) aliphatic ring and (C6-C30) aromatic ring; amino; mono- or di- (C1-C30)alkylamino; mono- or di- (C2-C30)alkenylamino; (C1-C30)alkyl(C2-C30)alkenylamino; mono- or di- (C6-C30)arylamino; (C1-C30)alkyl(C6-C30)arylamino; mono- or di- (3- to 30-membered)heteroarylamino; (C1-C30)alkyl(3- to 30-membered)heteroarylamino; (C2-C30)alkenyl(C6-C30)arylamino; (C2-C30)alkenyl(3- to 30-membered)heteroarylamino; (C6-C30)aryl(3- to 30-membered)heteroarylamino; (C1-C30)alkylcarbonyl; (C1-C30)alkoxycarbonyl; (C6-C30)arylcarbonyl; (C6-C30)aryl phosphine; 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. For example, the substituents of the above substituents may be, deuterium; methyl; cyclopentyl; a substituted or unsubstituted phenyl; biphenyl; dibenzofuranyl; dibenzothiophenyl; or a substituted or unsubstituted carbazolyl, etc.

Hereinafter, an organic electroluminescent material according to one embodiment and an organic electroluminescent device comprising the same will be described.

An organic electroluminescent device according to one embodiment includes: a first electrode; a second electrode; and at least one light emitting layer(s) positioned between the first electrode and the second electrode, wherein the light emitting layer includes a host and a dopant, wherein the host is a compound represented by the following formula 1 and a compound represented by the following formula 2, and the dopant includes a compound represented by the following formula 3.

According to one embodiment, the present disclosure includes a first host compound represented by formula 1 and a second host compound represented by formula 2 as host materials.

The host materials according to one embodiment may comprise a compound represented by the following formula 1.

in formula 1, La represents a single bond or a substituted or unsubstituted (C6-C30)arylene; Ma represents a substituted or unsubstituted (5- to 30- membered) heteroaryl containing nitrogen; and Xa to Xh each independently represent, hydrogen, deuterium, halogen, cyano, a substituted or unsubstituted (C1-C30)alkyl, a substituted or unsubstituted (C2-C30)alkenyl, a substituted or unsubstituted (C2-C30)alkynyl, a substituted or unsubstituted (C3-C30)cycloalkyl, a substituted or unsubstituted (C6-C30)aryl, a substituted or unsubstituted (3- to 30-membered)heteroaryl, a substituted or unsubstituted tri(C1-C30)alkylsilyl, a substituted or unsubstituted tri(C6-C30)arylsilyl, a substituted or unsubstituted di(C1-C30)alkyl(C6-C30)arylsilyl, or a substituted or unsubstituted mono- or di- (C6-C30)arylamino; or may be linked to the adjacent substituents to form a ring(s).

In one embodiment, La may be a single bond or a substituted or unsubstituted (C6-C25)arylene, preferably a single bond or a substituted or unsubstituted (C6-C18)aryiene, more preferably a single bond or a substituted or unsubstituted (C6-C12)arylene. For example, La may be a single bond, phenylene unsubstituted or substituted with phenyl, naphthylene, or biphenylene.

In one embodiment, Ma may be a substituted or unsubstituted (5- to 30-membered)heteroaryl containing at least one nitrogen, preferably a substituted or unsubstituted (5- to 25-membered)heteroaryl containing at least two nitrogens, more preferably a substituted or unsubstituted (5- to 18-membered)heteroaryl containing at least three nitrogens. For example, Ma may be a substituted or unsubstituted pyridinyl, a substituted or unsubstituted pyrimidinyl, a substituted or unsubstituted triazinyl, a substituted or unsubstituted quinazolinyl, or a substituted or unsubstituted quinoxalinyl. The substituents of the substituted groups may be at least one of phenyl unsubstituted or substituted with carbazolyl, biphenyl, dibenzofuranyl, dibenzothiophenyl, triazolyl substituted with at least one phenyl, and carbazolyl unsubstituted or substituted with phenyl.

In one embodiment, Xa to Xh each independently may be hydrogen, a substituted or unsubstituted (C6-C30)aryl or a substituted or unsubstituted (5- to 30-membered)heteroaryl; or may be linked to the adjacent substituents to form a ring(s), preferably hydrogen, a substituted or unsubstituted (C6-C25)aryl, or a substituted or unsubstituted (5- to 25-membered)heteroaryl; or may be linked to the adjacent substituents to form a substituted or unsubstituted (C3-C30) mono- or polycyclic, alicyclic, or aromatic ring, more preferably hydrogen, a substituted or unsubstituted (C6-C18)aryl, or a substituted or unsubstituted (5-to 18-membered)heteroaryl; or may be linked to the adjacent substituents to form a substituted or unsubstituted (C5-C30) polycyclic, aromatic ring. Wherein, the carbon atoms in the formed alicyclic or aromatic ring may be replaced with at least one heteroatom selected from the group consisting of N, O, and S. For example, Xa to Xh each independently may be hydrogen, phenyl, biphenyl, dibenzofuranyl unsubstituted or substituted with phenyl, dibenzothiophenyl unsubstituted or substituted with phenyl, or carbazolyl unsubstituted or substituted with phenyl; or may be linked to the adjacent substituents to form benzene ring, indole ring, indene ring, benzofuran ring, or benzothiophene ring. These fused rings may be substituted with (C1-C10)alkyl and/or (C6-C15)aryl and/or (5- to 18-membered)heteroaryl such as phenyl, biphenyl, dibenzofuranyl, or carbazolyl.

In one embodiment, the compound represented by formula 1 may be represented by any one of the following formulas 1-1 to 1-22.

in formulas 1-1 to 1-22,

• X and T each independently represent, O, S, or NR₂₉;
• R₂₉ represents a substituted or unsubstituted (C6-C30)aryl or a substituted or unsubstituted (3- to 30-membered)heteroaryl;
• La and Ma are as defined in formula1; and
• R₂₁ to R₂₈ and R_a to R_i are as defined as Xa to Xh in formula 1.

In one embodiment, R₂₉ may be a substituted or unsubstituted (C6-C30)aryl, preferably a substituted or unsubstituted (C6-C25)aryl, more preferably a substituted or unsubstituted (C6-C18)aryl. For example, R₂₉ may be a substituted or unsubstituted phenyl.

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 represented by formula 1 of the present disclosure may be prepared with reference to a synthesis method known to those skilled in the art. For example, it may be prepared by the synthesis methods known in Korean Patent Nos. 10-1423067 B1, 10-1396171 B1, or 10-1431644 B1, but is not limited thereto.

Another host material according to one embodiment may be the compound represented by the following formula 2.

in formula 2

A₁ and A₂ each independently represent, a substituted or unsubstituted (C6-C30)aryl, a substituted or unsubstituted dibenzofuranyl, a substituted or unsubstituted dibenzothiophenyl, or a substituted or unsubstituted carbazolyl; and

X₁₁ to X₂₆ each independently represent, hydrogen, deuterium, a substituted or unsubstituted (C6-C30)aryl, or a substituted or unsubstituted (3- to 30-membered)heteroaryl; or may be linked to the adjacent substituents to form a ring(s); provided that at least four of X₁₁ to X₂₆ are deuterium, and at least one of X₁₁, X₁₈, X₁₉, and X₂₆ is deuterium.

In one embodiment, A₁ and A₂ each independently may be a substituted or unsubstituted (C6-C25)aryl, a substituted or unsubstituted dibenzofuranyl, a substituted or unsubstituted dibenzothiophenyl, or a substituted or unsubstituted carbazolyl. Wherein the substituent of (C6-C25)aryl may be at least one of (C1-C6)alkyl; (C6-C20)aryl; and (5- to 15-membered)heteroaryl unsubstituted or substituted with (C6-C20)aryl. The substituent of dibenzofuranyl, dibenzothiophenyl, and carbazolyl may be at least one (C6-C12)aryl. For example, A₁ and A₂ each independently may be a substituted or unsubstituted phenyl, a substituted or unsubstituted p-biphenyl, a substituted or unsubstituted m-biphenyl, a substituted or unsubstituted o-biphenyl, a substituted or unsubstituted p-terphenyl, a substituted or unsubstituted m-terphenyl, a substituted or unsubstituted o-terphenyl, a substituted or unsubstituted naphthyl, a substituted or unsubstituted fluorenyl, a substituted or unsubstituted benzofluorenyl, a substituted or unsubstituted triphenylenyl, a substituted or unsubstituted fluoranthenyl, a substituted or unsubstituted phenanthrenyl, a substituted or unsubstituted dibenzofuranyl, a substituted or unsubstituted carbazolyl, or a substituted or unsubstituted dibenzothiophenyl. For example, A₁ and A₂ each independently may be phenyl, naphthyl, p-biphenyl, m-biphenyl, o-biphenyl, p-terphenyl, m-terphenyl, o-terphenyl, triphenylenyl, naphthylphenyl, phenylnaphthyl, phenyl substituted with triphenylenyl, naphthylphenyl, phenyl substituted with methyl, phenyl substituted with dibenzofuranyl, phenyl substituted with dibenzothiophenyl, dibenzofuranyl, dibenzothiophenyl, dibenzofuranyl substituted with phenyl, dibenzothiophenyl substituted with phenyl, carbazolyl substituted with phenyl, or carbazolyl substituted with naphthyl.

In one embodiment, X₁₁ to X₂₆ each independently may be hydrogen, deuterium, a substituted or unsubstituted (C6-C30)aryl, or a substituted or unsubstituted (3- to 30-membered) heteroaryl, preferably hydrogen, deuterium, a substituted or unsubstituted (C6-C12)aryl, or a substituted or unsubstituted (5- to 15-membered) heteroaryl, more preferably hydrogen or deuterium. Wherein, at least one of X₁₁, X₁₈, X₁₉, and X₂₆, preferably at least two of X₁₁, X₁₈, X₁₉, and X₂₆, more preferably at least three of X₁₁, X₁₈, X₁₉, and X₂₆, and even more preferably all of X₁₁, X₁₈, X₁₉, and X₂₆, may be deuterium.

According to one embodiment of the present disclosure, the degree of deuteration in one compound represented by formula 2 is 15% or more, preferably 30% or more, more preferably 40% or more, in relation to the numbers of the total carbon atoms. When the compound of formula 2 is deuterated following the degree of deuteration, the bond dissociation energy according to deuteration increases, thereby increasing the stability of the compound. When such a compound is used in an organic electroluminescent device, improved lifespan property may be exhibited.

In one embodiment, the compound represented by formula 2 may be represented by any one of the following formulas 2-1 to 2-8.

in formulas 2-1 to 2-8,

A₁, A₂, and X₁₁ to X₂₆ are as defined in formula 2.

According to one embodiment, the compound represented by formula 2 may be more specifically illustrated by the following compounds, but is not limited thereto.

In the compounds above, Dn means that n number of hydrogens is replaced with deuterium, wherein n represents an integer of 4 to 50. According to one embodiment, n is an integer of 4 or more, preferably an integer of 6 or more, more preferably an integer of 8 or more, and even more preferably an integer of 10 or more. When deuterated with a number equal to or higher than the lower limit, the bond dissociation energy according to deuteration increases, thereby exhibiting the increased stability of the compound, and exhibiting the improved lifespan property when the compound is used in an organic electroluminescent device.

The compound represented by formula 2 according to one embodiment can be prepared by a known synthetic method. For example, it may be prepared with reference to the following reaction scheme 1, but is not limited thereto.

In reaction scheme 1,

• A₁, A₂, and X₁₁ to X₂₆ are as defined in formula 2, and
• D_n means that n number of hydrogens is replaced with deuterium.

As described above, exemplary synthesis examples of the compounds represented by formula 2 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(ll)-catalyzed oxidative cyclization reaction, Grignard reaction, Heck reaction, Cyclic Dehydration reaction, SN₁ substitution reaction, SN₂ substitution reaction, and 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 formula 2, other than the substituents described in the specific synthesis examples, are bonded.

In addition, the deuterated compound of formula 2 can be prepared using a deuterated precursor material in a similar manner, or more generally can be prepared by treating a non-deuterated compound with a deuterated solvent, D6-benzene in the presence of a Lewis acid H/D exchange catalyst such as aluminum trichloride or ethyl aluminum chloride. In addition, the degree of deuterization can be controlled by varying reaction conditions such as reaction temperature. For example, the number of deuterium in formula 2 can be adjusted by controlling the reaction temperature and time, the equivalent of acid, etc.

The dopant materials according to one embodiment may comprise a compound represented by the following formula 3.

in formula 3,

• R₁ to R₈ each independently represent, hydrogen, deuterium, halogen, (C1-C30)alkyl unsubstituted or substituted with deuterium and/or (C3-C30)cycloalkyl, 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 may be linked to the adjacent substituents to form a ring(s); and
• R₉ to R₁₁ each independently represent, hydrogen, deuterium, halogen, (C1-C30)alkyl unsubstituted or substituted with deuterium, a substituted or unsubstituted (C3-C30)cycloalkyl, or a substituted or unsubstituted (C6-C30)aryl; or may be linked to the adjacent substituents to form a ring(s).

In one embodiment, R₁ to R₈ each independently may be, hydrogen, (C1-C30)alkyl unsubstituted or substituted with deuterium and/or (C3-C30)cycloalkyl, a substituted or unsubstituted (C3-C30)cycloalkyl, or a substituted or unsubstituted (C6-C30)aryl; or R₅ to R₈ may be linked to the adjacent substituents to form a ring(s), preferably hydrogen, (C1-C20)alkyl unsubstituted or substituted with deuterium and/or (C5-C20)cycloalkyl, (C3-C20)cycloalkyl unsubstituted or substituted with deuterium, or (C6-C25)aryl unsubstituted or substituted with (C1-C10)alkyl; or R₅ to R₈ may be linked to the adjacent substituents to form a substituted or unsubstituted (5- to 30-membered) mono- or polycyclic, alicyclic, aromatic ring, or a combination thereof, more preferably hydrogen, (C1-C10)alkyl unsubstituted or substituted with deuterium and/or (C5-C10)cycloalkyl, a substituted or unsubstituted (C3-C10)cycloalkyl, or a substituted or unsubstituted (C6-C18)aryl; or R₅ to R₈ may be linked to the adjacent substituents to form a substituted or unsubstituted (5- to 25-membered) mono-or polycyclic, or aromatic ring, e.g., may be fused with benzene to form a substituted or unsubstituted benzofuropyridine, a substituted or unsubstituted benzothienopyridine, a substituted or unsubstituted dibenzofuran, a substituted or unsubstituted dibenzothiophene. The substituent of the fused rings may be (C1-C10)alkyl unsubstituted or substituted with at least one deuterium. For example, R₁ to R₈ each independently may be hydrogen, (C1-C10)alkyl unsubstituted or substituted with at least one deuterium and/or cyclopentyl, e.g., may be methyl, ethyl, tert-propyl, tert-butyl, iso-butyl, or neo-pentyl, cyclopentyl unsubstituted or substituted with at least one deuterium, or phenyl unsubstituted or substituted with a substituted or unsubstituted (C1-C10)alkyl.

In one embodiment, R₉ to R₁₁ each independently may be hydrogen or (C1-C30)alkyl unsubstituted or substituted with deuterium, preferably hydrogen or (C1-C20)alkyl unsubstituted or substituted with deuterium, more preferably hydrogen or unsubstituted (C1-C10)alkyl. For example, R₁₀ may be hydrogen, and R₉ and R₁₁ each independently may be unsubstituted (C1-C10)alkyl.

In one embodiment, the compound represented by formula 3 may be represented by the following formula 3-1 or 3-2.

in formulas 3-1 and 3-2,

• R₁ to R₄ and R₇ to R₁₁ are as defined in formula 3;
• Y represents O or S;
• Z₁ to Z₄each independently represent, N or CR_a; and
• R_a represents hydrogen, deuterium, halogen, (C1-C30)alkyl unsubstituted or substituted with deuterium and/or (C3-C30)cycloalkyl, 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.

According to one embodiment, the compound represented by formula 3 may be more specifically illustrated by the following compounds, but is not limited thereto.

The compound represented by formula 3 of the present disclosure can be prepared by a known synthetic method. For example, it may be synthesized by the method disclosed in US 2016-0133859 A1 or US 2015-0315222 A1, but is not limited thereto.

According to another embodiment, the present disclosure provides an organic electroluminescent compound represented by the following formula 3′.

in formula 3′,

• R₁ to R₈ each independently represent, hydrogen, deuterium, halogen, (C1-C30)alkyl unsubstituted or substituted with deuterium and/or (C3-C30)cycloalkyl, 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 may be linked to the adjacent substituents to form a ring(s); and
• R₁₂ to R₁₇ each independently represent, hydrogen, deuterium, (C1-C6)alkyl unsubstituted or substituted with deuterium, or a substituted or unsubstituted (C3-C30)cycloalkyl;
• provided that the case where R₁₂ to R₁₇ are all hydrogen is excluded.

In one embodiment, R₁ to R₈ each independently may be hydrogen, (C1-C30)alkyl unsubstituted or substituted with deuterium and/or (C3-C30)cycloalkyl, a substituted or unsubstituted (C3-C30)cycloalkyl, or a substituted or unsubstituted (C6-C30)aryl; or R₅ and R₈ may be linked to the adjacent substituents to form a ring(s); preferably hydrogen, (C1-C20)alkyl unsubstituted or substituted with deuterium and/or (C5-C20)cycloalkyl, (C3-C20)cycloalkyl unsubstituted or substituted with deuterium, or (C6-C25)aryl unsubstituted or substituted with (C1-C10)alkyl; or R₅ to R₈ may be linked to the adjacent substituents to form a substituted or unsubstituted (5- to 30-membered) mono- or polycyclic, alicyclic, aromatic ring, or a combination thereof, more preferably hydrogen, (C1-C10)alkyl unsubstituted or substituted with deuterium and/or (C5-C10)cycloalkyl, a substituted or unsubstituted (C3-C10)cycloalkyl, or a substituted or unsubstituted (C6-C18)aryl; or R₅ to R₈ may be linked to the adjacent substituents to form a substituted or unsubstituted (5- to 25-membered) mono-or polycyclic or aromatic ring, e.g., may be fused with benzene to form a substituted or unsubstituted benzofluropyridine, a substituted or unsubstituted benzothienopyridine, a substituted or unsubstituted dibenzofuran, or a substituted or unsubstituted dibenzothiophene. The substituent of the fused rings may be (C1-C10)alkyl unsubstituted or substituted with at least one deuterium. For example, R₁ to R₈ each independently may be hydrogen, (C1-C10)alkyl unsubstituted or substituted with at least one deuterium and/or cyclopentyl, e.g., may be methyl, ethyl, tert-propyl, tert-butyl, iso-butyl, or neo-pentyl, cyclopentyl unsubstituted or substituted with at least one deuterium, or phenyl unsubstituted or substituted with a substituted or unsubstituted (C1-C10)alkyl.

In one embodiment, R₁₂ to R₁₇ each independently may be hydrogen, deuterium, (C1-C6)alkyl unsubstituted or substituted with deuterium, or a substituted or unsubstituted (C5-C30)cycloalkyl, preferably hydrogen or (C1-C6)alkyl unsubstituted or substituted with deuterium, more preferably hydrogen or unsubstituted (C1-C6)alkyl.

In one embodiment, in formula 3,

and

each independently may be selected from the structures listed below:

In one embodiment, the compound represented by formula 3′ may be represented by the following formula 3′-1 or 3′-2.

in formulas 3′-1 and 3′-2,

• R₁ to R₄, R₇, R₈, and R₁₂ to R₁₇ are as defined in formula 3′;
• Y represents O or S;
• Z₁ to Z₄ each independently represents N or CR_a; and
• R_a represents hydrogen, deuterium, halogen, (C1-C30)alkyl unsubstituted or substituted with deuterium and/or (C3-C30)cycloalkyl, 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.

According to one embodiment, the compound represented by formula 3′ may be more specifically illustrated by the following compounds, but is not limited thereto.

Hereinafter, an organic electroluminescent device to which the aforementioned host material and dopant material are applied will be described.

The organic electroluminescent device according to one embodiment includes a first electrode; a second electrode; and at least one organic layer(s) interposed between the first electrode and the second electrode, wherein the organic layer includes at least one light-emitting layer. The light-emitting layer includes host materials comprising a compound represented by formula 1 and a compound represented by formula 2, and a dopant material comprising a compound represented by formula 3. Wherein the weight ratio of the first host compound represented by formula 1 to the second host compound represented by formula 2 may be in the range of about 1:99 to about 99:1, preferably about 10:90 to about 90:10, more preferably about 30:70 to about 70:30, more preferably about 40:60 to about 60:40, and even more preferably about 50:50 in the light-emitting layer.

The light-emitting layer according to the present disclosure comprises at least one of compound(s) H1-1 to H1-210 and H1′-1 to H1′-270 as the first host material, which is represented by formula 1 and at least one of compound(s) H2-1 to H2-145 as the second host material, which is represented by formula 2, and at least one of compounds D-1 to D-280 as the dopant compound, which is represented by formula 3. For example, the host materials and the dopant material may be included in the same light-emitting layer, or may be included in different light-emitting layers, respectively.

In the organic electroluminescent device according to an embodiment, the doping concentration of the dopant material to the host material in the light-emitting layer, may be less than 20 wt%, preferably less than 15 wt%.

The organic layer 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 in addition to the light-emitting layer. The organic layer may further comprise an amine-based compound and/or an azine-based compound other than the light-emitting material according to the present disclosure. Specifically, the hole injection layer, the hole transport layer, the hole auxiliary layer, the light-emitting layer, the light-emitting auxiliary layer, or the electron blocking layer may contain the amine-based compound, e.g., an arylamine-based compound and a styrylarylamine-based compound, etc., as a hole injection material, a hole transport material, a hole auxiliary material, a light-emitting material, a light-emitting auxiliary material, or an electron blocking material. Also, the electron transport layer, the electron injection layer, the electron buffer layer, or the hole blocking layer may contain the azine-based compound as an electron transport material, an electron injection material, an electron buffer material, or a hole blocking material. 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.

The 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), YG (yellowish green), or B (blue) 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).

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.

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 may be placed between the electron transport layer (or electron injection layer) and the light-emitting layer, and blocks the arrival of holes to the cathode, thereby improving the probability of recombination of electrons and holes in the light-emitting layer. 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 of a pair of electrodes. 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 addition, 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. Also, 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.

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 spin coating, dip coating, flow coating methods, etc., can be used. 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.

When forming a layer by the host materials and the dopant materials according to one embodiment, the layer can be formed by the above-listed methods, and can often be formed by co-deposition or mixture-deposition. The co-deposition is a mixed deposition method in which two or more materials are put into respective individual crucible sources and a current is applied to both cells simultaneously to evaporate the materials; and the mixed deposition is a method in which two or more materials are mixed in one crucible source before deposition, and then a current is applied to one cell to evaporate the materials.

According to one embodiment, when the first host compound and the second host compound are present in the same layer or different layers in the organic electroluminescent device, the two host compounds may be individually formed. For example, after depositing the first host material, a second host material may be deposited.

According to one embodiment, the present disclosure can provide display devices comprising host materials and a dopant material. In addition, by using the organic electroluminescent device of the present disclosure, display devices such as smartphones, tablets, notebooks, PCs, TVs, or display devices for vehicles, or lighting devices such as outdoor or indoor lighting can be prepared.

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

[Example 1] Synthesis of Compound D-132

1) Synthesis of Compound 3

Compound 1 (30 g, 202.7 mmol), compound 2 (51.6 g, 243.3 mmol), Pd(PPh₃)₄ (7 g, 6.08 mmol), K₂CO₃ (64.5 g, 608 mmol), 500 mL of toluene, 250 mL of ethanol (EtOH), and 250 mL of H₂O were added into a flask, and then stirred under reflux for 3 hours. Upon completion of the reaction, after cooling to room temperature, the mixture was stirred at room temperature, methanol (MeOH) was added thereto, and the resulting solid was filtered under reduced pressure. Thereafter, it was separated by column chromatography (methyl chloride/hexane (MC/Hex)) to obtain compound 3 (30 g, 53%).

2) Synthesis of Compound 5

Compound 3 (25 g, 89.4 mmol), compound 4 (16 g, 116 mmol), Pd₂(dba)₃ (4.9 g, 5.4 mmol), S-Phos (3.2 g, 7.87 mmol), K₃PO₄ (957 g, 268.2 mmol), and 600 mL of toluene were added into a flask, and then stirred under reflux for 18 hours. Upon completion of the reaction, after cooling to room temperature, the mixture was stirred at room temperature, methanol (MeOH) was added thereto, and the resulting solid was filtered under reduced pressure. Thereafter, it was separated by column chromatography (MC/Hex) to obtain compound 5 (23.5 g, 78.9%).

3) Synthesis of Compound 6

Compound 5 (11 g, 34.2 mmol) and IrCI₃ (4.6 g, 15.6 mmol) were added into 2-ethoxyethanol/H₂O=3/1 (150 mL/50 mL), and then the mixture was stirred under reflux for 24 hours. Upon completion of the reaction, after cooling to room temperature, the mixture was stirred at room temperature, and the resulting solid was filtered and dried to obtain compound 6 (12 g, 85.7%).

4) Synthesis of Compound D-132

Compound 6 (12 g, 6.7 mmol), acetylacetone (Acac) (2 g, 20 mmol), Na₂CO₃, (3.6 g, 33.5 mmol), and 100 mL of 2-ethoxyethanol were added into a flask, and then reacted at 110° C. for 12 hours. After completion of the reaction, the resulting solid was filtered and dried. Thereafter, it was separated by column chromatography (MC/Hex) to obtain compound D-132 (6 g, 93%).

	MW	UV	PL	M.P
D-132	960.12	310 nm	555 nm	400° C.

[Example 2] Synthesis of Compound D-241

1) Synthesis of Compound 8

Compound 7 (20 g, 76.83 mmol) and IrCl₃ (10.43 g, 34.92 mmol) were added into 2-ethoxyethanol/H₂O=3/1 (270 mL/90 mL), and then the mixture was stirred under reflux for 24 hours. Upon completion of the reaction, after cooling to room temperature, the mixture was stirred at room temperature, and the resulting solid was filtered and dried to obtain compound 8 (22 g, 84%).

2) Synthesis of Compound D-241

Compound 8 (10 g, 6.7 mmol), compound 9 (4.83 g, 20.1 mmol), Na₂CO₃ (4.26 g, 40.2 mmol), and 120 mL of 2-ethoxyethanol were added into a flask, and then reacted at 110° C. for 12 hours. After completion of the reaction, the resulting solid was filtered and dried. Thereafter, it was separated by column chromatography (MC/Hex) to obtain compound D-241 (5.2 g, 41%).

	MW	UV	PL	M.P
D-241	950.17	324 nm	543 nm	367° C.

Hereinafter, the preparation method of an organic electroluminescent device comprising the host materials and the dopant materials according to the present disclosure, and the device property thereof will be explained in order to understand the present disclosure in detail.

[Device Example 1] Preparation of OLED Comprising the Host Materials and the Dopant Materials According to the Present Disclosure

An OLED according to the present disclosure was prepared. First, a transparent electrode indium tin oxide (ITO) thin film (10 Ω/sq) on a glass substrate for an OLED (GEOMATEC CO., LTD., Japan) was subjected to an ultrasonic washing with acetone and isopropyl alcohol, sequentially, and thereafter was stored in isopropanol and then used. Thereafter, the ITO substrate was mounted on a substrate holder of a vacuum vapor deposition apparatus. Then, compound HI-1 as a first hole injection compound was introduced into a cell of the vacuum vapor deposition apparatus, and compound HT-1 as first hole transport compound was introduced into another cell. The two materials were evaporated at different rates and the first hole injection compound was deposited in a doping amount of 3 wt% based on the total amount of the first hole injection compound and the first hole transport compound to form a hole injection layer having a thickness of 10 nm. Next, compound HT-1 was deposited as a first hole transport layer having a thickness of 80 nm on the 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 30 nm on the first hole transport layer. After forming the hole injection layer and the hole transport layers, a light-emitting layer was formed thereon as follows: each of the first host and the second host materials described in the following Table 1 were introduced into two cells of the vacuum vapor deposition apparatus as hosts, respectively, and compound D-3 was introduced into another cell as a dopant. The two host materials were evaporated at a different rate of 1:2 and the dopant material was evaporated at a different rate, simultaneously, and was deposited in a doping amount of 10 wt% based on the total amount of the hosts and dopant to form a light-emitting layer having a thickness of 40 nm on the second hole transport layer. Next, compounds ETL-1 and EIL-1 as electron transport materials were deposited at a weight ratio of 40:60 to form an electron transport layer having a thickness of 35 nm on the light-emitting layer. After depositing compound EIL-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. Each compound used for all the materials were purified by vacuum sublimation under 10^-6 torr.

[Comparative Example 1] Preparation of OLED Comprising Conventional Compounds as a Host

An OLED was produced in the same manner as in Device Example 1, except that compound T-1 was used as the second host material and compound D-132 was used as the dopant, of the light-emitting layer.

The luminous color and the time taken for luminance to decrease from 100% to 80% at a luminance of 20,000 nits (lifespan; T80) of the OLEDs according to Device Example 1 and Comparative Example 1 produced as described above, were measured, and the results thereof are shown in the following Table 1.

	First Host Compound	Second Host Compound	Dopant	Lifespan (T80, hr)	Luminous Color
Device Example 1	H1′-235	H2-50	D-3	280	Yellow-green
Comparative Example 1	H1′-235	T-1	D-132	199	Yellow-green

[Device Example 2] Preparation of OLED Comprising the Host Materials and the Dopant Materials According to the Present Disclosure

An OLED was produced in the same manner as in Device Example 1, except that compound D-156 was used as the dopant of the light-emitting layer.

[Device Example 3] Preparation of OLED Comprising the Host Materials and the Dopant Materials According to the Present Disclosure

An OLED was produced in the same manner as in Device Example 1, except that compound H1-36 was used as the first host material of the light-emitting layer.

[Comparative Example 2] Preparation of OLED Comprising Conventional Compounds as a Host

An OLED was produced in the same manner as in Device Example 1, except that compound T-1 was used as the second host material and compound D-156 was used as the dopant, of the light-emitting layer.

[Comparative Example 3] Preparation of OLED Comprising Conventional Compounds as a Host

An OLED was produced in the same manner as in Device Example 1, except that compounds H1-36 and T-1 were used as the first and the second host materials of the light-emitting layer, respectively.

The luminous color and the time taken for luminance to decrease from 100% to 50% at a luminance of 20,000 nits (lifespan; T50) of the OLEDs according to Device Examples 2 to 3 and Comparative Examples 2 and 3 produced as described above, were measured, and the results thereof are shown in the following Table 2.

	First Host Compound	Second Host Compound	Dopant	Lifespan (T50, hr)	Luminous Color
Device Example 2	H1′-235	H2-50	D-156	311	Green
Device Example 3	H1-36	H2-50	D-3	422	Green
Comparative Example 2	H1′-235	T-1	D-156	250	Green
Comparative Example 3	H1-36	T-1	D-3	341	Green

[Device Example 4] Preparation of OLED Comprising the Host Materials and the Dopant Materials According to the Present Disclosure

An OLED was produced in the same manner as in Device Example 1, except that compound H1′-268 was used alone as a host and compound D-241 was used as a dopant, of the light-emitting layer.

[Comparative Example 4] Preparation of OLED Comprising Conventional Compound as a Dopant

An OLED was produced in the same manner as in Device Example 4, except that compound D-156 was used as the dopant of the light-emitting layer.

The driving voltage, the power efficiency, and the luminous color at a luminance of 10,000 nits of the OLEDs according to Device Example 5 and Comparative Example 5 were measured, and the results thereof are shown in the following Table 3:

	Host	Dopant	Driving Voltage (V)	Power Efficient (Lm/W)	Luminous Color
Device Example 4	H1’-268	D-241	2.9	115.3	Green
Comparative Example 4	H1’-268	D-156	3.0	92.6	Green

The organic electroluminescent device including the organic electroluminescent material according to the present disclosure not only exhibited excellent luminous property, in particular it exhibited significantly improved lifespan property, compared to the conventional light-emitting materials.

The compounds used in Device Examples and Comparative Examples are specifically shown in the following Table 4.

Hole Injection Layer / Hole Transport Layer
Light-Emitting Layer
Electron Transport Layer/ Electron Injection Layer

Claims

1. An organic electroluminescent device including a first electrode; a second electrode; and at least one light-emitting layer(s) positioned between the first electrode and the second electrode, wherein the light-emitting layer includes a host comprising a compound represented by the following formula 1 and a compound represented by the following formula 2, and a dopant comprising a compound represented by the following formula 3.

2. The organic electroluminescent device according to claim 1, wherein the formula 1 is represented by any one of the following formulas 1-1 to 1-22:

3. The organic electroluminescent device according to claim 1, wherein the formula 2 is represented by any one of the following formulas 2-1 to 2-8:

4. The organic electroluminescent device according to claim 1, wherein the formula 3 is represented by the following formula 3-1 or 3-2:

5. The organic electroluminescent device according to claim 1, wherein A1 and A2 of the formula 2 each independently represent, a substituted or unsubstituted phenyl, a substituted or unsubstituted biphenyl, a substituted or unsubstituted terphenyl, a substituted or unsubstituted naphthyl, a substituted or unsubstituted fluorenyl, a substituted or unsubstituted benzofluorenyl, a substituted or unsubstituted triphenylenyl, a substituted or unsubstituted fluoranthenyl, a substituted or unsubstituted phenanthrenyl, a substituted or unsubstituted dibenzofuranyl, a substituted or unsubstituted carbazolyl, or a substituted or unsubstituted dibenzothiophenyl.

6. The organic electroluminescent device according to claim 1, wherein the compound represented by formula 1 is selected from the following compounds:

7. The organic electroluminescent device according to claim 1, wherein the compound represented by formula 2 is selected from the following compounds: wherein, Dn means that n number of hydrogens is replaced with deuterium, wherein n represents an integer of 4 to 50.

8. The organic electroluminescent device according to claim 1, wherein the compound represented by formula 3 is selected from the following compounds:

9. An organic electroluminescent compound represented by the following formula 3′:

10. The organic electroluminescent compound according to claim 9, wherein the formula 3′ is represented by the following formula 3′-1 or 3′-2:

11. The organic electroluminescent compound according to claim 9, wherein

12. The organic electroluminescent compound according to claim 9, wherein the compound represented by formula 3’ is selected from the following compounds: