Patent Application
20230255102
The present disclosure relates to a plurality of host materials and an organic electroluminescent device comprising the same.
In 1987, Tang et al. of Eastman Kodak first developed a small molecular green organic electroluminescent device (OLED) by using TPD/Alq3 bilayer consisting of a light-emitting layer and a charge transport layer. Thereafter, the development of OLEDs was rapidly effected and OLEDs have been commercialized. Currently, OLEDs mainly use phosphorescent materials having excellent luminous efficiency in panel implementation. However, in many applications such as TVs and lightings, the lifespan of OLEDs is insufficient, and higher efficiency of OLEDs is still required. In general, the lifespan of an OLED becomes shorter as the luminance of the OLED becomes higher. Thus, OLEDs having high luminous efficiency and/or long lifespan are required for long-term use and high resolution of a display.
In order to improve luminous efficiency, driving voltage, and/or lifespan, various materials or concepts for an organic layer of an organic electroluminescent device have been proposed, but they were not satisfactory in practical use. Accordingly, there has been a continuous need to develop an organic electroluminescent material having improved performances, for example, improved driving voltage, luminous efficiency, power efficiency, and/or lifespan properties, compared to a combination of specific compounds previously disclosed.
Meanwhile, Japanese Patent Application Laid-Open No. 2015-18883 discloses a plurality of host materials containing anthracene and/or cyclopentaphenanthrene structures, and Korean Patent Application Laid-Open No. 2019-0140421 discloses a compound containing an anthracene structure as a host material. In addition, Chinese Patent Application Laid-Open No. 110294663 discloses a compound containing a cyclopentaphenanthrene structure as a host material. However, the aforementioned references do not specifically disclose a specific combination of host materials claimed herein. In addition, there has been a continuous need to develop a light-emitting material having more improved performances, for example, improved driving voltage, luminous efficiency, power efficiency and/or lifespan properties, compared to the compound disclosed in the aforementioned references.
The objective of the present disclosure is to provide a plurality of host materials capable of producing an organic electroluminescent device with low driving voltage, high current efficiency and/or improved lifespan properties. Another objective of the present disclosure is to provide an organic electroluminescent device with low driving voltage, high current efficiency and/or improved lifespan properties by comprising a specific combination of compounds according to the present disclosure as a plurality of host materials.
As a result of intensive research to solve the above technical problems, the present inventors found that the above objective can be achieved by a plurality of host materials comprising at least one first host compound represented by the following formula 1 and at least one second host compound represented by the following formula 2, wherein the first host compound and the second host compound are different from each other. In addition, the present inventors found that the above objective can be achieved by a plurality of host materials comprising at least one first host compound and at least one second host compound, wherein the first host compound and the second host compound are represented by the following formula 2′, and wherein the first host compound and the second host compound are different from each other.
In formula 1,
In formula 2′, ArA represents the following formula A-1:
wherein,
An organic electroluminescent device having lower driving voltage, higher current efficiency and/or improved lifespan properties compared to a conventional organic electroluminescent device may be manufactured by comprising a specific combination of compounds according to the present disclosure as a plurality of host materials, and it is possible to manufacture a display system or a lighting system using the same.
Hereinafter, the present disclosure will be described in detail. However, the following description is intended to explain the present disclosure, and is not meant to restrict the scope of the present disclosure.
The present disclosure relates to a plurality of host materials comprising a first host material comprising at least one compound represented by formula 1 and a second host material comprising at least one compound represented by formula 2, wherein the compound represented by formula 1 and the compound represented by formula 2 are different from each other, and an organic electroluminescent device comprising the host materials. In addition, present disclosure relates to a plurality of host materials comprising at least one first host compound and at least one second host compound, wherein the first host compound and the second host compound are represented by formula 2′, and wherein the first host compound and the second host compound are different from each other.
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 (including a host material and a dopant material), an electron buffer material, a hole blocking material, an electron transport material, an electron injection material, etc.
The term “a plurality of organic electroluminescent materials” in the present disclosure means an organic electroluminescent material(s) comprising a combination of two or more 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 two or more compounds that 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. The two or more compounds may be comprised in the same layer or different layers, and may be mixture-evaporated or co-evaporated, or may be individually evaporated.
The term “a plurality of host materials” in the present disclosure means an organic electroluminescent material(s) comprising a combination of two or more host materials. 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). The plurality of host materials of the present disclosure may be comprised in any light-emitting layer constituting an organic electroluminescent device, wherein the two or more compounds comprised in the plurality of host materials may be comprised together in one light-emitting layer or may be respectively comprised in different light-emitting layers. When two or more host materials are comprised in one layer, for example, they may be mixture-evaporated to form a layer or separately and simultaneously co-evaporated to form a layer.
Herein, the term “(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. 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.
The term “(C6-C30)aryl,” “(C6-C30)arylene,” or “(C6-C30)arene” is meant to be a monocyclic or fused ring radical derived from an aromatic hydrocarbon having 6 to 30 ring backbone carbon atoms, which may be partially saturated, in which the number of ring backbone carbon atoms is preferably 6 to 20, and more preferably 6 to 15. The above aryl may comprise a spiro structure. The above aryl may include phenyl, biphenyl, terphenyl, quarterphenyl, 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-fluoren]yl, spiro[fluorene-benzofluoren]yl, azulenyl, tetramethyldihydrophenanthrenyl, etc. More specifically, the aryl may include o-tolyl, m-tolyl, p-tolyl, 2,3-xylyl, 3,4-xylyl, 2,5-xylyl, mesityl, o-cumenyl, m-cumenyl, p-cumenyl, p-tert-butylphenyl, p-(2-phenylpropyl)phenyl, 4′-methylbiphenyl, 4″-tert-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]fluorenyl, 11,11-dimethyl-5-benzo[a]fluorenyl, 11,11 -dimethyl-6-benzo[a]fluorenyl, 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]fluorenyl, 11,11-diphenyl-1-benzo[a]fluorenyl, 11,11-diphenyl-2-benzo[a]fluorenyl, 11,11 -diphenyl-3-benzo[a]fluorenyl, 11,11 -diphenyl-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[b]fluorenyl, 11,11 -diphenyl-7-benzo[b]fluorenyl, 11,11-diphenyl-8-benzo[b]fluorenyl, 11,11-diphenyl-9-benzo[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]fluorenyl, 11,11 -diphenyl-9-benzo[c]fluorenyl, 11,11-diphenyl-10-benzo[c]fluorenyl, 9,9,10,10-tetramethyl-9,10-dihydro-1-phenanthrenyl, 9,9,10,10-tetramethyl-9,10-dihydro-2-phenanthrenyl, 9,9,10,10-tetramethyl-9,10-dihydro-3-phenanthrenyl, 9,9,10,10-tetramethyl-9,10-dihydro-4-phenanthrenyl, etc.
The term “(3- to 30-membered)heteroaryl,” “(3- to 30-membered)heteroarylene,” or “(3-to 30-membered)heteroarene” in the present disclosure means an aryl group or an arylene group having 3 to 30 ring backbone atoms and including at least one, preferably 1 to 4 heteroatom(s) selected from the group consisting of B, N, O, S, Si, and P. The number of ring backbone atoms is preferably 3 to 30, and more preferably 5 to 20. It may be a monocyclic ring or a fused ring condensed with at least one benzene ring, and may be partially saturated. In addition, the above heteroaryl or heteroarylene comprises 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. The above heteroaryl may include a monocyclic ring-type heteroaryl such as 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 such as benzofuranyl, benzothiophenyl, isobenzofuranyl, dibenzofuranyl, dibenzothiophenyl, benzofuroquinolinyl, benzofuroquinazolinyl, benzofuronaphthyridinyl, benzofuropyrimidinyl, naphthofuropyrimidinyl, benzothienoquinolinyl, benzothienoquinazolinyl, benzothienonaphthyridinyl, benzothienopyrimidinyl, naphthothienopyrimidinyl, pyrimidoindolyl, benzopyrimidoindolyl, benzofuropyrazinyl, naphthofuropyrazinyl, benzothienopyrazinyl, naphthothienopyrazinyl, pyrazinoindolyl, benzopyrazinoindolyl, benzimidazolyl, 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, imidazopyridyl, chromenoquinazolinyl, thiochromenoquinazolinyl, dimethylbenzopyrimidinyl, indolocarbazolyl, indenocarbazolyl, etc. More specifically, the heteroaryl may include 1-pyrrolyl, 2-pyrrolyl, 3-pyrrolyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, 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-imidazopyridyl, 3-imidazopyridyl, 5-imidazopyridyl, 6-imidazopyridyl, 7-imidazopyridyl, 8-imidazopyridyl, 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, azacarbazolyl-1-yl, azacarbazolyl-2-yl, azacarbazolyl-3-yl, azacarbazolyl-4-yl, azacarbazolyl-5-yl, azacarbazolyl-6-yl, azacarbazolyl-7-yl, azacarbazolyl-8-yl, azacarbazolyl-9-yl, 1-phenanthridinyl, 2-phenanthridinyl, 3-phenanthridinyl, 4-phenanthridinyl, 6-phenanthridinyl, 7-phenanthridinyl, 8-phenanthridinyl, 9-phenanthridinyl, 10-phenanthridinyl, 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-tert-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-tert-butyl-1-indolyl, 4-tert-butyl-1-indolyl, 2-tert-butyl-3-indolyl, 4-tert-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-b]-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-d]pyrimidinyl, 2-benzothio[3,2-d]pyrimidinyl, 6-benzothio[3,2-d]pyrimidinyl, 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, etc.
The term “a fused ring group of a (C3-C30)aliphatic ring(s) and a (C6-C30)aromatic ring(s)” means a fused ring group of at least one aliphatic ring(s) having 3 to 30 ring backbone carbon atoms, preferably 3 to 25 ring backbone carbon atoms, and more preferably 3 to 18 ring backbone carbon atoms and at least one aromatic ring(s) having 6 to 30 ring backbone carbon atoms, preferably 6 to 25 ring backbone carbon atoms, and more preferably 6 to 18 ring backbone carbon atoms, for example, a fused ring group of at least one benzene and at least one cyclohexane, or a fused ring group of at least one naphthalene and at least one cyclopentane, etc. In the present disclosure, the carbon atom of the fused ring group of a (C3-C30)aliphatic ring(s) and a (C6-C30)aromatic ring(s) may be replaced with at least one heteroatom(s) selected from B, N, O, S, Si, and P, preferably at least one heteroatom(s) selected from N, O, and S. In the present disclosure, “halogen” includes F, Cl, Br, and I.
In addition, “ortho (o-),” “meta (m-),” and “para (p-)” are prefixes, which represent the relative positions of substituents, respectively. Ortho indicates that two substituents are adjacent to each other, and for example, when two substituents in a benzene derivative occupy positions 1 and 2, it is called an ortho position. Meta indicates that two substituents are at positions 1 and 3, and for example, when two substituents in a benzene derivative occupy positions 1 and 3, it is called a meta position. Para indicates that two substituents are at positions 1 and 4, and for example, when two substituents in a benzene derivative occupy positions 1 and 4, it is called a para position.
The term “a ring formed by a linkage of adjacent substituents” means that at least two adjacent substituents are linked to or fused with each other to form a substituted or unsubstituted mono- or polycyclic (3- to 30-membered) alicyclic or aromatic ring, or the combination thereof, preferably a substituted or unsubstituted mono- or polycyclic (5- to 25-membered) alicyclic or aromatic ring, or the combination thereof. In addition, the formed ring may contain at least one heteroatom selected from B, N, O, S, Si, and P, preferably at least one heteroatom selected from N, O, and S. According to one embodiment of the present disclosure, the number of ring backbone atoms is 5 to 20, and according to another embodiment of the present disclosure, the number of ring backbone atoms is 5 to 15. For example, the fused ring may be in the form of 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, 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 another functional group (i.e., a substituent), and also includes that the hydrogen atom is replaced with a group formed by a linkage of two or more substituents of the above substituents. For example, the “group formed by a linkage of two or more substituents” may be pyridine-triazine. That is, pyridine-triazine may be interpreted as a heteroaryl substituent, or as substituents in which two heteroaryls are linked. In formulas of the present disclosure, the substituent(s) of the substituted alkyl, the substituted alkenyl, the substituted aryl, the substituted arylene, the substituted heteroaryl, the substituted heteroarylene, the substituted cycloalkyl, the substituted cycloalkenyl, the substituted heterocycloalkyl, the substituted alkoxy, the substituted trialkylsilyl, the substituted dialkylarylsilyl, the substituted alkyldiarylsilyl, the substituted triarylsilyl, the substituted fused ring group of an aliphatic ring(s) and an aromatic ring(s), the substituted mono- or di- alkylamino, the substituted mono- or di- alkenylamino, the substituted mono- or di- arylamino, the substituted mono- or di- heteroarylamino, the substituted alkylalkenylamino, the substituted alkylarylamino, the substituted alkylheteroarylamino, the substituted alkenylarylamino, the substituted alkenylheteroarylamino, the substituted arylheteroarylamino, the substituted arene ring, the substituted heteroarene ring, and the substituted naphthalene ring each independently are at least one selected from the group consisting of deuterium; a halogen; a cyano; a carboxyl; a nitro; a hydroxyl; a phosphine oxide; a (C1-C30)alkyl unsubstituted or substituted with deuterium; a halo(C1-C30)alkyl; a (C2-C30)alkenyl; a (C2-C30)alkynyl; a (C1-C30)alkoxy; a (C1-C30)alkylthio; a (C3-C30)cycloalkyl; a (C3-C30)cycloalkenyl; a (3- to 7-membered)heterocycloalkyl; a (C6-C30)aryloxy; a (C6-C30)arylthio; a (3- to 30-membered)heteroaryl unsubstituted or substituted with at least one of deuterium and a (C6-C30)aryl(s); a (C6-C30)aryl unsubstituted or substituted with at least one of deuterium, a (C1-C30)alkyl(s), a (C6-C30)aryl(s), and a (3- to 30-membered)heteroaryl(s); tri(C1-C30)alkylsilyl; a tri(C6-C30)arylsilyl; a di(C1-C30)alkyl(C6-C30)arylsilyl; a (C1-C30)alkyldi(C6-C30)arylsilyl; an amino; a mono- or di- (C1-C30)alkylamino; a mono- or di-(C2-C30)alkenylamino; a mono- or di- (C6-C30)arylamino; a mono- or di- (3- to 30-membered)heteroarylamino; a (C1-C30)alkyl(C2-C30)alkenylamino; a (C1-C30)alkyl(C6-C30)arylamino; a (C1-C30)alkyl(3- to 30-membered)heteroarylamino; a (C2-C30)alkenyl(C6-C30)arylamino; a (C2-C30)alkenyl(3- to 30-membered)heteroarylamino; a (C6-C30)aryl(3- to 30-membered)heteroarylamino; a (C1-C30)alkylcarbonyl; a (C1-C30)alkoxycarbonyl; a (C6-C30)arylcarbonyl; a di(C6-C30)arylboronyl; a (C6-C30)arylphosphine; a di(C1-C30)alkylboronyl; a (C1-C30)alkyl(C6-C30)arylboronyl; a (C6-C30)aryl(C1-C30)alkyl; and a (C1-C30)alkyl(C6-C30)aryl, which may be further substituted with deuterium. According to one embodiment of the present disclosure, the substituent(s), each independently, are at least one selected from the group consisting of deuterium; a (C1-C20)alkyl unsubstituted or substituted with deuterium; a (3- to 20-membered)heteroaryl unsubstituted or substituted with at least one of deuterium and a (C6-C20)aryl(s); and a (C6-C30)aryl unsubstituted or substituted with at least one of deuterium, a (C1 -C20)alkyl(s), a (C6-C20)aryl(s), and a (6- to 20-membered)heteroaryl(s). For example, the substituent(s), each independently, may be at least one selected from the group consisting of deuterium, a methyl, a phenyl, a naphthyl, a biphenyl, a terphenyl, a phenanthrenyl, a dimethylfluorenyl, a dibenzofuranyl, a dibenzothiophenyl, and a carbazolyl, wherein the above substituents may be further substituted with deuterium.
Hereinafter, a plurality of host materials according to one embodiment will be described in more detail.
A plurality of host materials according to the present disclosure comprise a first host material and a second host material, wherein the first host material comprises at least one compound represented by formula 1, and the second host material comprises at least one compound represented by formula 2, wherein the compound represented by formula 1 and the compound represented by formula 2 are different from each other.
The first host material, which is a host material according to one embodiment, is represented by the following formula 1.
In formula 1,
According to one embodiment of the present disclosure, L1 and L2 each independently represent a single bond or a substituted or unsubstituted (C6-C30)arylene, preferably a single bond or a (C6-C20)arylene unsubstituted or substituted with deuterium. For example, L1 and L2 may each independently be a single bond, a phenylene unsubstituted or substituted with deuterium, a naphthylene unsubstituted or substituted with deuterium, or a phenanthrenylene unsubstituted or substituted with deuterium.
According to one embodiment of the present disclosure, Ar1 and Ar2 each independently represent a substituted or unsubstituted (C6-C30)aryl, preferably a (C6-C30)aryl unsubstituted or substituted with at least one of deuterium and a (C6-C30)aryl(s), and more preferably a (C6-C28)aryl unsubstituted or substituted with at least one of deuterium and a (C6-C20)aryl(s). For example, Ar1 and Ar2 may each independently be a substituted or unsubstituted phenyl, a substituted or unsubstituted biphenyl, a substituted or unsubstituted terphenyl, a substituted or unsubstituted naphthyl, or a substituted or unsubstituted phenanthrenyl, wherein the substituent(s) of the substituted phenyl, the substituted biphenyl, the substituted terphenyl, the substituted naphthyl, and the substituted phenanthrenyl may each independently be at least one of deuterium, a phenyl, a biphenyl, a terphenyl, a naphthyl, and a phenanthrenyl.
According to one embodiment of the present disclosure, R1 to R8 may each independently be hydrogen or deuterium.
The second host material, which is the other host material according to one embodiment, comprises the compound represented by the following formula 2.
In formula 2, ArA represents the following formula A-1 or A-2:
wherein,
According to one embodiment of the present disclosure, ring A and ring B each independently represent a substituted or unsubstituted (C6-C30)arene ring, or a substituted or unsubstituted (3- to 30-membered)heteroarene ring, preferably a substituted or unsubstituted (C6-C20)arene ring, or a substituted or unsubstituted (6- to 20-membered)heteroarene ring, and more preferably a (C6-C20)arene ring unsubstituted or substituted with at least one of deuterium and a (C1-C10)alkyl(s); or a (6- to 20-membered)heteroarene ring unsubstituted or substituted with at least one of deuterium and a (C6-C15)aryl(s). For example, ring A and ring B may each independently be a benzene ring, a naphthalene ring, a dimethylfluorene ring, a dibenzofuran ring, or a carbazole ring substituted with a phenyl(s), which may be further substituted with deuterium.
According to one embodiment of the present disclosure, ring C may be a naphthalene ring unsubstituted or substituted with deuterium.
According to one embodiment of the present disclosure, R19 and R20 may each independently be a site linked to L12; or may be hydrogen or deuterium.
According to one embodiment of the present disclosure, R11 to R18 may each independently be hydrogen or deuterium.
According to one embodiment of the present disclosure, R31 to R34 may each independently be a site linked to L12; or may be hydrogen or deuterium.
According to one embodiment of the present disclosure, Ra and Rb may each independently represent a substituted or unsubstituted (C1-C20)alkyl, preferably a substituted or unsubstituted (C1-C10)alkyl. For example, Ra and Rb may each independently be a methyl unsubstituted or substituted with deuterium.
According to one embodiment of the present disclosure, L11 to L13 each independently represent a single bond, a substituted or unsubstituted (C6-C25)arylene, or a substituted or unsubstituted (3- to 28-membered)heteroarylene, preferably a single bond; a (C6-C18)arylene unsubstituted or substituted with deuterium; or a (6- to 20-membered)heteroarylene unsubstituted or substituted with deuterium. For example, L11 to L13 may each independently be a single bond, a phenylene unsubstituted or substituted with deuterium, a biphenylene unsubstituted or substituted with deuterium, a naphthylene unsubstituted or substituted with deuterium, or a carbazolylene unsubstituted or substituted with deuterium.
According to one embodiment of the present disclosure, Ar11 represents a substituted or unsubstituted (C6-C28)aryl or a substituted or unsubstituted (3- to 25-membered)heteroaryl, preferably a (C6-C28)aryl unsubstituted or substituted with at least one of deuterium, a (C1-C10)alkyl(s), a (C6-C20)aryl(s), and a (6- to 25-membered)heteroaryl(s); or a (3- to 25-membered)heteroaryl unsubstituted or substituted with at least one of deuterium and a (C6-C20)aryl(s). For example, Ar11 may be at least one of a substituted or unsubstituted, phenyl, biphenyl, terphenyl, naphthyl, phenanthrenyl, triphenylenyl, fluorenyl, dimethylfluorenyl, spirobifluorenyl, benzofluorenyl, dimethylbenzofluorenyl, dibenzofuranyl, dibenzothiophenyl, carbazolyl, benzonaphthofuranyl, or benzonaphthothiophenyl, of which the substituent(s) may be at least one of deuterium, a methyl, a phenyl, a biphenyl, a naphthyl, a phenanthrenyl, a dimethylfluorenyl, a dibenzofuranyl, a dibenzothiophenyl, and a carbazolyl.
According to one embodiment of the present disclosure, ArA may be represented by any one of the following formulas b-1 to b-4.
In formulas b-1 to b-4,
According to one embodiment of the present disclosure, R21 to R26 each independently represent a site linked to L12, or represent hydrogen or deuterium; or may be linked to an adjacent substituent(s) to form a ring(s). According to one embodiment of the present disclosure, a ring(s) formed by a linkage of adjacent substituents of R21 to R26 may be a substituted or unsubstituted mono- or polycyclic (3- to 30-membered) alicyclic or aromatic ring, or the combination thereof, which may contain at least one heteroatom(s) selected from B, N, O, S, Si, and P. For example, a ring(s) formed by a linkage of adjacent substituents of R21 to R26 may be a benzene ring unsubstituted or substituted with deuterium, a dimethylindene ring unsubstituted or substituted with deuterium, a benzofuran ring unsubstituted or substituted with deuterium, or a phenylindole ring unsubstituted or substituted with deuterium, etc.
According to one embodiment of the present disclosure, formula 2 may be represented by the following formula 2-1 or 2-2.
In formulas 2-1 and 2-2,
According to one embodiment of the present disclosure, R21 to R26 each independently represent hydrogen or deuterium; or may be linked to an adjacent substituent(s) to form a ring(s). According to one embodiment of the present disclosure, a ring(s) formed by a linkage of adjacent substituents of R21 to R26 may be a substituted or unsubstituted mono- or polycyclic (3- to 30-membered) alicyclic or aromatic ring, or the combination thereof, which may contain at least one heteroatom(s) selected from B, N, O, S, Si, and P. For example, a ring(s) formed by a linkage of adjacent substituents of R21 to R26 may be a benzene ring unsubstituted or substituted with deuterium, a dimethylindene ring unsubstituted or substituted with deuterium, a benzofuran ring unsubstituted or substituted with deuterium, or a phenylindole ring unsubstituted or substituted with deuterium, etc.
According to one embodiment of the present disclosure, R27 to R29 each independently represent a site linked to L12, or represent hydrogen or deuterium.
According to one embodiment of the present disclosure, formula 2 may be represented by the following formula 3-1.
In formula 3-1,
R31 to R36 and R40 are as defined for R11 to R18, and T2, R11 to R18, L11, L12, and Ar11 are as defined in formula 2.
According to one embodiment of the present disclosure, at least one of formulas 1 and 2 may comprise deuterium.
According to one embodiment of the present disclosure, the first host material represented by formula 1 may be more specifically exemplified as the following compounds, but is not limited thereto.
In compounds C-56 to C-100, C-102, and C-104, Dn means that n number of hydrogen atoms are replaced with deuterium, and n is an integer from 1 to 34. Specifically, n is at least 1, and is an integer equal to the maximum number of hydrogen atoms in the compound.
According to one embodiment of the present disclosure, if a compound represented by formula 1 contains deuterium, the compound contains at least one deuterium, preferably at least one of R1 to R8 contains deuterium, more preferably each of R1 to R8 and —L1—(Ar1)a contain at least one deuterium, still more preferably each of R1 to R8, —L1Ar1)a, and —L2—(Ar2)b contain at least one deuterium. According to one embodiment of the present disclosure, if a compound represented by formula 1 contains deuterium, the deuterium substitution rate is preferably 20% or more, more preferably 30% or more, still more preferably 40% or more, much more preferably 45% or more of the total number of hydrogen atoms. The compound of formula 1 substituted with the deuterium substitution rate may increase the bond dissociation energy due to deuteration to increase the stability of the compound, and an organic electroluminescent device comprising the compound may exhibit improved lifespan properties.
According to one embodiment of the present disclosure, the second host material represented by formula 2 may be more specifically exemplified as the following compounds, but is not limited thereto.
In compounds H1-226 to H1-285 and H1-291 to H1-295, Dn means that n number of hydrogen atoms are replaced with deuterium, and n is an integer from 1 to 30. Specifically, n is at least 1, and is an integer equal to the maximum number of hydrogen atoms in the compound.
In compounds H2-66 to H2-115, Dn means that n number of hydrogen atoms are replaced with deuterium, and n is an integer from 1 to 33. Specifically, n is at least 1, and is an integer equal to the maximum number of hydrogen atoms in the compound.
According to one embodiment of the present disclosure, if a compound represented by formula 2 contains deuterium, the compound contains at least one deuterium, preferably at least one of R11 to R18 contain deuterium, more preferably each of R11 to R18 and —L11—Ar11; or each of R11 to R18 and —L12—ArA contain at least one deuterium, still more preferably each of R11 to R18, —L11—Ar11, and —L12—ArA contain at least one deuterium. According to one embodiment of the present disclosure, if a compound represented by formula 2 contains deuterium, the deuterium substitution rate is preferably 20% or more, more preferably 30% or more, still more preferably 40% or more, and much more preferably 45% or more of the total number of hydrogen atoms. The compound of formula 2 substituted with the deuterium substitution rate may increase the bond dissociation energy due to deuteration to increase the stability of the compound, and an organic electroluminescent device comprising the compound may exhibit improved lifespan properties.
Hereinafter, the plurality of host materials according to one embodiment of the present disclosure will be described in detail.
The plurality of host materials according to the present disclosure comprises at least one first host compound and at least one second host compound, wherein the first host compound and the second host compound are represented by the following formula 2′, and wherein the first host compound and the second host compound are different from each other.
The first host compound and the second host compound, which are host materials according to one embodiment of the present disclosure, are represented by the following formula 2′.
In formula 2′, ArA represents the following formula A-1:
wherein,
According to one embodiment of the present disclosure, formula 2′ may be represented by the following formula 2-1 or 2-2.
In formulas 2-1 and 2-2,
According to one embodiment of the present disclosure, the first host material and the second host material comprising the compound represented by formula 2′ may be more specifically exemplified as the following compounds, but is not limited thereto.
In compounds H1-226 to H1-285 and H1-291 to H1-295, Dn means that n number of hydrogen atoms are replaced with deuterium, and n is an integer from 1 to 30. Specifically, n is at least 1, and is an integer equal to the maximum number of hydrogen atoms in the compound.
According to one embodiment of the present disclosure, if a compound represented by formula 2′ contains deuterium, the compound contains at least one deuterium, preferably at least one of R11 to R18 contain deuterium, more preferably each of R11 to R18 and —L11—Ar11; or each of R11 to R18 and —L12—ArA contain at least one deuterium, still more preferably each of R11 to R18, —L11—Ar11, and —L12—ArA contain at least one deuterium. According to one embodiment of the present disclosure, if a compound represented by formula 2′ contains deuterium, the deuterium substitution rate is preferably 20% or more, more preferably 30% or more, still more preferably 40% or more, much more preferably 45% or more of the total number of hydrogen atoms. The compound of formula 2′ substituted with the deuterium substitution rate may increase the bond dissociation energy due to deuteration to increase the stability of the compound, and an organic electroluminescent device comprising the compound may exhibit improved lifespan properties.
The compounds represented by formulas 1, 2, and 2′ according to the present disclosure may be prepared by synthetic methods known to one skilled in the art. For example, the compound represented by formula 1 of the present disclosure may be prepared by referring to Korean Patent Application Laid-Open No. 2021-0046437, etc., but is not limited thereto. The compounds represented by formulas 2 and 2′ of the present disclosure may be prepared by referring to Korean Patent Application Laid-Open No. 2010-0109060 and Chinese Patent Application Laid-Open No. 110294663, etc., but is not limited thereto. The compound which is substituted with deuterium among the compounds represented by formulas 1, 2, and 2′ may be prepared by referring to Korean Patent Application Laid-Open No. 2012-0101029, etc. in addition to the aforementioned references, but is not limited thereto.
Although illustrative synthesis examples of the compounds represented by formulas 1, 2, and 2′ are described above, one skilled in the art will be able to readily understand that all of them are based on a Buchwald-Hartwig cross-coupling reaction, an N-arylation reaction, H-mont-mediated etherification reaction, a Miyaura borylation reaction, a Suzuki cross-coupling reaction, an intramolecular acid-induced cyclization reaction, a Pd(II)-catalyzed oxidative cyclization reaction, a Grignard reaction, a Heck reaction, a Cyclic Dehydration reaction, an SN, substitution reaction, an SN2 substitution reaction, a Phosphine-mediated reductive cyclization reaction, etc., and the reactions above proceed even when substituents, which are defined in formulas 1, 2, and 2′ but are not specified in the specific synthesis examples, are bonded.
Hereinafter, an organic electroluminescent device to which the plurality of host materials described above is applied will be described.
According to one embodiment of the present disclosure, an organic electroluminescent device comprises a first electrode; a second electrode; and at least one organic layer interposed between the first electrode and the second electrode, wherein the organic layer comprises a light-emitting layer, wherein the light-emitting layer may comprise a plurality of host materials comprising at least one first host material represented by formula 1 above and at least one second host material represented by formula 2 above, and wherein the first host material and the second host material are different from each other.
According to one embodiment of the present disclosure, the organic electroluminescent material of the present disclosure comprises at least one compound selected from compounds C-1 to C-104, which is a first host material, and at least one compound selected from compounds H1-1 to H1-295 and H2-1 to H2-115, which is a second host material. The plurality of host materials may be comprised in the same organic layer, for example, a light-emitting layer, or each may be comprised in different light-emitting layers.
According to another embodiment of the present disclosure, an organic electroluminescent device comprises a first electrode; a second electrode; and at least one organic layer interposed between the first electrode and the second electrode, wherein the organic layer comprises a light-emitting layer, wherein the light-emitting layer may comprise a plurality of host materials comprising at least one first host material and at least one second host material which are represented by formula 2′, wherein the first host material and the second host material are different from each other.
According to one embodiment of the present disclosure, the organic electroluminescent material of the present disclosure comprises at least one compound selected from compounds H1-1 to H1-295 as a first host material and a second host material, respectively, wherein the first host material and the second host material are different from each other. The plurality of host materials may be comprised in the same organic layer, for example, a light-emitting layer, or each may be comprised in different light-emitting layers.
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 azine-based compound in addition to the light-emitting material of 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 comprise an amine-based compound, for example, an arylamine-based compound, 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, and an electron blocking material. In addition, the electron transport layer, the electron injection layer, the electron buffer layer, and the hole blocking layer may comprise an azine-based compound as an electron transport material, an electron injection material, an electron buffer material, and a hole blocking material. Further, the organic layer may further comprise at least one metals selected from the group consisting of group 1, group 2, 4th period transition metals, 5th period transition metals, lanthanide metals, and organic metals of d-transition elements, or at least one complex compound comprising such metal.
The plurality of host materials according to the present disclosure may be used as light-emitting materials for a white organic light-emitting device. The white organic light-emitting device has been suggested in various structures such as a side-by-side structure or a stacking structure depending on the arrangement of R (Red), G (Green) or YG (Yellowish Green), and B (Blue) light-emitting parts, or a color conversion material (CCM) method, etc. In addition, the plurality of host materials according to the present disclosure may also be used in the organic electroluminescent device comprising a quantum dot (QD).
One of the first electrode and the second electrode may be an anode, and the other may be a cathode. In this case, each of the first electrode and the second electrode may be formed of a transparent conductive material or a transflective or reflective conductive material. Depending on the type of material forming the first electrode and the second electrode, the organic electroluminescent device may be a top emission type, a bottom emission type, or a both-sides emission type.
A hole injection layer, a hole transport layer, an electron blocking layer, or a combination thereof may be used between an anode and a light-emitting layer. The hole injection layer may be multilayers 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 two compounds may be simultaneously used in each of the multilayers. In addition, the hole injection layer may be doped with a p-dopant. The electron blocking layer may be placed between the hole transport layer (or hole injection layer) and the light-emitting layer, and may block overflow of electrons from the light-emitting layer and confine the excitons in the light-emitting layer to prevent light leakage. The hole transport layer or the electron blocking layer may be multilayers, wherein a plurality of compounds may be used in each of the multilayers.
An electron buffer layer, a hole blocking layer, an electron transport layer, an electron injection layer, or a combination thereof may be used between a light-emitting layer and a cathode. The electron buffer layer may be multilayers in order to control electron injection and improve interfacial properties between the light-emitting layer and the electron injection layer, wherein two compounds may be simultaneously used in each of the multilayers. The hole blocking layer is a layer located between an electron transport layer (or electron injection layer) and a light-emitting layer and prevents holes from reaching the cathode, thereby improving the recombination probability of electrons and holes in the light-emitting layer. The hole blocking layer or the electron transport layer may also be multilayers, wherein a plurality of compounds may be used in each of the multilayers. In addition, the electron injection layer may be doped with an n-dopant.
The light-emitting auxiliary layer is a layer placed between an anode and a light-emitting layer, or between a cathode and a light-emitting layer. When the light-emitting auxiliary layer is placed between the anode and the light-emitting layer, it may be used to facilitate injection and/or transport of holes or to prevent the overflow of electrons. When the light-emitting auxiliary layer is placed between the cathode and the light-emitting layer, it may be used to facilitate injection and/or transport of electrons or to prevent the overflow of holes. In addition, the hole auxiliary layer may be placed between a hole transport layer (or a hole injection layer) and a light-emitting layer to exhibit an effect of facilitating or blocking transport rate (or injection rate) of holes, thereby enabling the charge balance to be controlled. When the organic electroluminescent device comprises two or more hole transport layers, the hole transport layer, which is further comprised, may be used as a hole auxiliary layer or an 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 lifespan of the organic electroluminescent device.
In the organic electroluminescent device of the present disclosure, at least one layer selected from a chalcogenide layer, a metal halide layer, and a metal oxide layer (hereinafter, “a surface layer”) may be preferably placed on an inner surface(s) of one or both electrodes. Specifically, a chalcogenide (including oxides) layer of silicon or aluminum is preferably placed on an anode surface of an electroluminescent medium layer, and a metal halide layer or a metal oxide layer is preferably placed on a cathode surface of an electroluminescent medium layer. The surface layer may provide operation stability for the organic electroluminescent device. Preferably, the chalcogenide includes SiOx (1≤X≤2), AlOx (1≤X≤1.5), SiON, SiAlON, etc.; the metal halide 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 is preferably 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. Further, 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, which emits white light.
An organic electroluminescent device according to one embodiment of the present disclosure may further comprise at least one dopant in the light-emitting layer.
The dopants comprised in the organic electroluminescent device of the present disclosure may be at least one phosphorescent or fluorescent dopant, and is preferably a fluorescent dopant. The phosphorescent dopant materials applied to the organic electroluminescent device according to the present disclosure are not particularly limited, but may be selected from metallated complex compounds of iridium (Ir), osmium (Os), copper (Cu), and platinum (Pt), preferably selected from ortho-metallated complex compounds of iridium (Ir), osmium (Os), copper (Cu), and platinum (Pt), and more preferably an ortho-metallated iridium complex compound.
The dopant comprised in the organic electroluminescent device of the present disclosure may be a compound represented by the following formula D, but is not limited thereto.
In formula D,
In another embodiment of the present disclosure, R101 to R111 may each independently be hydrogen, deuterium, an unsubstituted (C1-C10)alkyl; a (C6-C18)aryl unsubstituted or substituted with at least one of a (C1-C10)alkyl(s), a (13- to 18-membered)heteroaryl(s), and a di(C6-C18)arylamino(s); a (5- to 18-membered)heteroaryl unsubstituted or substituted with a (C1-C10)alkyl(s); or —L′4—N—(Ar′4)(Ar′5); or may be linked to an adjacent substituent to form a ring(s). For example, R101 to R111 may each independently be hydrogen, a methyl, a tert-butyl, a substituted or unsubstituted phenyl, a biphenyl, a terphenyl, a triphenylenyl, a carbazolyl, a phenoxazinyl, a phenothiazinyl, a dimethylacridinyl, a dimethylxanthenyl, a diphenylamino unsubstituted or substituted with at least one of a methyl(s) and a diphenylamino(s), a phenylnaphthylamino, a dibiphenylamino, a phenylamino substituted with a phenylcarbazolyl(s) or a dibenzofuranyl(s), or a (17- to 21-membered)heteroaryl substituted with at least one of a methyl(s) and a phenyl(s); or may be linked to an adjacent substituent to form a benzene ring, an indole ring substituted with at least one of a phenyl(s) and a diphenylamino(s), a benzofuran ring, a benzothiophene ring, or a 19-membered hetero ring substituted with a methyl(s). The substituent(s) of the substituted phenyl may be at least one of a methyl, a carbazolyl, a dibenzofuranyl, a diphenylamino, a phenoxazinyl, a phenothiazinyl, and a dimethylacridinyl.
According to one embodiment, the compound represented by formula D above may be exemplified as the following compounds, but is not limited thereto.
In the compounds above, D2 to D5 mean that two (2) to five (5) hydrogen atoms have been replaced with deuterium.
Each layer of the organic electroluminescent device of the present disclosure may be formed by any one method of dry film-forming methods such as vacuum evaporation, sputtering, plasma, ion plating, etc., or wet film-forming methods such as spin coating, dip coating, flow coating, etc. When using a wet film-forming method, a thin film can be formed by dissolving or diffusing materials forming each layer into any suitable solvent such as ethanol, chloroform, tetrahydrofuran, dioxane, etc. The solvent can be any one where the material forming each layer is soluble or dispersible in the solvent and where there are no problems in film formation capability.
In addition, the first and the second host materials according to one embodiment of the present disclosure may be film-formed by the above-listed methods, commonly by a co-evaporation process or a mixture-evaporation process. The co-evaporation is a mixed deposition method in which two or more materials are placed in a respective individual crucible source and a current is applied to both cells at the same time to evaporate the materials. The mixture-evaporation is a mixed deposition method in which two or more materials are mixed in one crucible source before evaporation, and a current is applied to the cell to evaporate the materials.
When the first and second host materials are present in the same layer or in different layers in an organic electroluminescent device according to one embodiment of the present disclosure, the two host compounds may be film-formed individually, respectively. For example, the second host material may be evaporated after the first host material is evaporated.
The present disclosure may provide a display system comprising a plurality of host materials comprising a first host material represented by formula 1 and a second host material represented by formula 2; or a plurality of host materials comprising a first host material and a second host material which are represented by formula 2′. In addition, it is possible to produce a display system, e.g., a display system for smartphones, tablets, notebooks, PCs, TVs, or cars, or a lighting system, e.g., an outdoor or indoor lighting system by using an organic electroluminescent device of the present disclosure.
Hereinafter, driving voltage, current efficiency, CIE color coordinate, and lifespan properties of an OLED according to the present disclosure will be explained. However, the following examples only explain the properties of the OLED according to the present disclosure for a detailed understanding of the present disclosure, and the present disclosure is not limited to the following examples.
An OLED according to the present disclosure was produced. 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 then was stored in isopropyl alcohol. The ITO substrate was mounted on a substrate holder of a vacuum vapor deposition apparatus. Compound HI was introduced into a cell of the vacuum vapor deposition apparatus, and compound HT-1 was introduced into another cell. The two materials were evaporated at different rates, and compound HI was deposited in a doping amount of 3 wt% based to the total amount of compound HI and compound HT-1 to form a hole injection layer with a thickness of 10 nm. Subsequently, compound HT-1 was deposited on the hole injection layer to form a first hole transport layer with a thickness of 80 nm. Next, compound HT-2 was introduced into another cell of the vacuum vapor deposition apparatus and was evaporated by applying an electric current to the cell, thereby depositing a second hole transport layer with a thickness of 5 nm on the first hole transport layer. After forming the hole injection layer and the hole transport layers, a light-emitting layer was deposited thereon as follows: Compounds shown in Tables 1, 2, and 4 to 7 below were introduced into two cells of the vacuum vapor deposition apparatus at a ratio of 1:1 as hosts and compound BD was introduced into another cell as a dopant. The dopant material was simultaneously evaporated at a different rate, and the dopant was deposited in a doping amount of 2 wt% based on the total amount of the hosts and dopant to form a light-emitting layer with a thickness of 20 nm on the second hole transport layer. Compound EI-1 and compound EI-2 were introduced into two other cells and evaporated at a rate of 1:1 to form an electron transport layer having a thickness of 35 nm on the light-emitting layer. After depositing compound EI-2 as an electron injection layer with a thickness of 2 nm, an Al cathode was deposited with a thickness of 80 nm by using another vacuum vapor deposition apparatus, thereby producing an OLED. Each compound for each material was purified by vacuum sublimation under 10-6 torr before use.
OLEDs were produced in the same manner as in Device Examples 1-1 to 1-3, 2-1 to 2-3, 4-1 to 4-4, 5-1 to 5-3, 6-1 to 6-3, and 7-1 to 7-3, except that a compound shown in Tables 1, 2, and 4 to 7 below was used alone as a host material of a light-emitting layer.
An OLED was produced in the same manner as in Device Examples 1-1 to 1-3, 2-1 to 2-3, 4-1 to 4-4, 5-1 to 5-3, 6-1 to 6-3, and 7-1 to 7-3, except that a light-emitting layer was deposited using the compounds shown in Table 3 below as host materials of a light-emitting layer, and compound ET-1 was deposited as an electron buffer layer with a thickness of 5 nm, which was followed by introducing compound EI-1 and compound EI-2 into two different cells and evaporating them at a rate of 1:1 to deposit an electron transport layer with a thickness of 30 nm on the light-emitting layer.
OLEDs were produced in the same manner as in Device Example 3-1, except that a compound shown in Table 3 below was used alone as a host material of a light-emitting layer.
The driving voltage, current efficiency (cd/A), and CIE color coordinate at a luminance of 1,000 nit, and the minimum time taken for reduction of luminance from 100% to 95% (lifespan: T95) at a luminance of 1,280 nit of the OLEDs produced in the above Device Examples and Comparative Examples are provided in Tables 1 to 7 below.
From Tables 1 to 7 above, it can be confirmed that the organic electroluminescent devices comprising a specific combination of compounds according to the present disclosure as host materials exhibit lower driving voltage, higher current efficiency and/or improved lifespan properties, especially significantly improved lifespan properties, compared to the organic electroluminescent devices comprising the conventional compound as a single host material.
The compounds used in the Device Examples and Comparative Examples are shown in Table 8 below.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2022-0008481 | Jan 2022 | KR | national |
| 10-2022-0178324 | Dec 2022 | KR | national |
