Patent Description:
Organic electroluminescent devices are self-luminous devices in which electrons injected from an electron injecting electrode (cathode) recombine with holes injected from a hole injecting electrode (anode) in a light emitting layer to form excitons, which emit light while releasing energy. Such organic electroluminescent devices have the advantages of low driving voltage, high luminance, large viewing angle, and short response time and can be applied to full-color light emitting flat panel displays. Due to these advantages, organic electroluminescent devices have received attention as next-generation light sources.

The above characteristics of organic electroluminescent devices are achieved by structural optimization of organic layers of the devices and are supported by stable and efficient materials for the organic layers such as hole injecting materials, hole transport materials, light emitting materials, electron transport materials, electron injecting materials, and electron blocking materials. However, more research still needs to be done to develop structurally optimized organic layers for organic electroluminescent devices and stable and efficient materials for organic layers of organic electroluminescent devices.

As such, there is a continued need to develop structures of organic electroluminescent devices optimized to improve their luminescent properties and new materials capable of supporting the optimized structures of organic electroluminescent devices. Known polycyclic aromatic compounds as light-emitting materials for organic light-emitting devices are described, for example, in <CIT> and <CIT>.

Accordingly, the present invention intends to provide an organic electroluminescent compound that is employed in an organic layer of an organic electroluminescent device to achieve high efficiency of the device. The present invention also intends to provide an organic electroluminescent device including the organic electroluminescent compound.

One aspect of the present invention provides a compound as defined in the appended claims.

A further aspect of the present invention provides an organic electroluminescent device including a first electrode, a second electrode opposite to the first electrode, and one or more organic layers interposed between the first and second electrodes wherein one of the organic layers includes at least one of the specific polycyclic aromatic compounds as defined in the appended claims.

The polycyclic aromatic derivative of the present invention can be employed in an organic layer of an organic electroluminescent device to achieve high efficiency of the device.

The present invention will now be described in more detail.

Described herein but not according to the present invention is a polycyclic aromatic derivative for use in an organic electroluminescent device, represented by Formula A:
<CHM>
wherein Q<NUM> to Q<NUM> are identical to or different from each other and are each independently a substituted or unsubstituted C<NUM>-C<NUM> aromatic hydrocarbon ring or a substituted or unsubstituted C<NUM>-C<NUM> aromatic heterocyclic ring, each X is independently selected from B, P, P=O, and P=S, each Y is independently selected from N-R<NUM>, CR<NUM>R<NUM>, O, S, Se, and SiR<NUM>R<NUM>, and R<NUM> to R<NUM> are identical to or different from each other and are each independently selected from hydrogen, deuterium, substituted or unsubstituted C<NUM>-C<NUM> alkyl, substituted or unsubstituted C<NUM>-C<NUM> aryl, substituted or unsubstituted C<NUM>-C<NUM> cycloalkyl, substituted or unsubstituted C<NUM>-C<NUM> heteroaryl, substituted or unsubstituted C<NUM>-C<NUM> alkoxy, substituted or unsubstituted C<NUM>-C<NUM> aryloxy, substituted or unsubstituted C<NUM>-C<NUM> alkylthioxy, substituted or unsubstituted C<NUM>-C<NUM> arylthioxy, substituted or unsubstituted C<NUM>-C<NUM> alkylamine, substituted or unsubstituted C<NUM>-C<NUM> arylamine, substituted or unsubstituted C<NUM>-C<NUM> alkylsilyl, substituted or unsubstituted C<NUM>-C<NUM> arylsilyl, nitro, cyano, and halogen, with the proviso that each of R<NUM> to R<NUM> is optionally bonded to one of the rings Q<NUM> and Q<NUM> to form an alicyclic or aromatic monocyclic or polycyclic ring, R<NUM> and R<NUM> are optionally linked to each other to form an alicyclic or aromatic monocyclic or polycyclic ring, and R<NUM> and R<NUM> are optionally linked to each other to form an alicyclic or aromatic monocyclic or polycyclic ring.

X in Formula A may be boron (B). The presence of boron (B) in the structure of the polycyclic aromatic derivative ensures high efficiency and long lifetime of the organic electroluminescent device.

The use of the polycyclic aromatic derivative makes the organic electroluminescent device highly efficient and long lasting.

The polycyclic aromatic derivative represented by Formula A has the following structural features:.

According to the structural features of the polycyclic aromatic derivative represented by Formula A , when either Q<NUM> or Q<NUM> is selected from the structures represented by Structural Formulae B-<NUM> to B-<NUM>, Formula A may have one of the following skeleton structures represented by Formulae A-<NUM> to A-<NUM>:
<CHM>
<CHM>
wherein X, Y, R, and Q<NUM> to Q<NUM> are as defined in Formula A.

According to the structural features of the polycyclic aromatic derivative represented by Formula A as described herein, when both Q<NUM> and Q<NUM> are selected from the structures represented by Structural Formulae B-<NUM> to B-<NUM>, Formula A may have one of the following skeleton structures represented by Formulae A-<NUM> to A-<NUM>:
<CHM>
<CHM>
<CHM>
wherein X, Y, R, Q<NUM>, Q<NUM>, Q<NUM>, and Q<NUM> are as defined in Formula A.

According to the structural features of the polycyclic aromatic derivative represented by Formula A as described herein, when Q<NUM> is selected from the structures represented by Structural Formulae B-<NUM> to B-<NUM>, Formula A may have one of the following skeleton structures represented by Formulae A-<NUM> to A-<NUM>:
<CHM>
<CHM>
wherein X, Y, Q<NUM>, Q<NUM>, Q<NUM>, Q<NUM>, and Q<NUM> are as defined in Formula A.

According to the structural features of the polycyclic aromatic derivative represented by Formula A as described herein, when Q<NUM> is selected from the structures represented by Structural Formulae B-<NUM> to B-<NUM> and either Q<NUM> or Q<NUM> is selected from the structures represented by Structural Formulae B-<NUM> to B-<NUM>, Formula A may have one of the following skeleton structures represented by Formulae A-<NUM> to A-<NUM>:
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
wherein X, Y, Q<NUM>, Q<NUM>, Q<NUM>, Q<NUM>, and Q<NUM> are as defined in Formula A.

According to the structural features of the polycyclic aromatic derivative represented by Formula A as described herein, when Q<NUM> is selected from the structures represented by Structural Formulae B-<NUM> to B-<NUM> and both Q<NUM> and Q<NUM> are selected from the structures represented by Structural Formulae B-<NUM> to B-<NUM>, Formula A may have one of the following skeleton structures represented by Formulae A-<NUM> to A-<NUM>:
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
wherein X, Y, R, Q<NUM>, Q<NUM>, and Q<NUM> are as defined in Formula A.

Although not specified in Formulae <NUM> to <NUM>, it should be understood that Q<NUM> and Q<NUM> are identical to or different from each other and are each independently from the structures represented by Structural Formulae B-<NUM> to B-<NUM>.

The use of the various polycyclic aromatic skeleton structures such as the structures represented by Formulae A-<NUM> to A-<NUM> meets the desired requirements of various organic layers of organic electroluminescent devices to achieve high efficiency and long lifetime of the devices.

Q<NUM> to Q<NUM> may be identical to or different from each other and may be each independently represented by Structural Formula Q-<NUM>:
<CHM>
wherein each Z is independently CR or N and each R is independently selected from hydrogen, deuterium, substituted or unsubstituted C<NUM>-C<NUM> alkyl, substituted or unsubstituted C<NUM>-C<NUM> aryl, substituted or unsubstituted C<NUM>-C<NUM> cycloalkyl, substituted or unsubstituted C<NUM>-C<NUM> heteroaryl, substituted or unsubstituted C<NUM>-C<NUM> alkoxy, substituted or unsubstituted C<NUM>-C<NUM> aryloxy, substituted or unsubstituted C<NUM>-C<NUM> alkylthioxy, substituted or unsubstituted C<NUM>-C<NUM> arylthioxy, substituted or unsubstituted C<NUM>-C<NUM> alkylamine, substituted or unsubstituted C<NUM>-C<NUM> arylamine, substituted or unsubstituted C<NUM>-C<NUM> alkylsilyl, substituted or unsubstituted C<NUM>-C<NUM> arylsilyl, nitro, cyano, and halogen, with the proviso that the groups R are optionally bonded to each other or are each independently optionally linked to an adjacent substituent to form an alicyclic or aromatic monocyclic or polycyclic ring, one or more of the carbon atoms in the alicyclic or aromatic monocyclic or polycyclic ring are optionally replaced with heteroatoms selected from N, S, and O, and Z structurally bonded to each of the adjacent X and Y is C-H unless otherwise defined.

As used herein, the term "substituted" in the definition of Q<NUM> to Q<NUM>, R, R<NUM> to R<NUM>, and R<NUM> to R<NUM> indicates substitution with one or more substituents selected from deuterium, cyano, halogen, hydroxyl, nitro, C<NUM>-C<NUM> alkyl, C<NUM>-C<NUM> cycloalkyl, C<NUM>-C<NUM> haloalkyl, C<NUM>-C<NUM> alkenyl, C<NUM>-C<NUM> alkynyl, C<NUM>-C<NUM> heteroalkyl, C<NUM>-C<NUM> heterocycloalkyl, C<NUM>-C<NUM> aryl, C<NUM>-C<NUM> arylalkyl, C<NUM>-C<NUM> heteroaryl, C<NUM>-C<NUM> heteroarylalkyl, C<NUM>-C<NUM> alkoxy, C<NUM>-C<NUM> alkylamino, C<NUM>-C<NUM> arylamino, C<NUM>-C<NUM> heteroarylamino, C<NUM>-C<NUM> alkylsilyl, C<NUM>-C<NUM> arylsilyl, and C<NUM>-C<NUM> aryloxy, or a combination thereof. As used herein, the term "unsubstituted" indicates having no substituent.

In the "substituted or unsubstituted C<NUM>-C<NUM> alkyl", "substituted or unsubstituted C<NUM>-C<NUM> aryl", etc., the number of carbon atoms in the alkyl or aryl group indicates the number of carbon atoms constituting the unsubstituted alkyl or aryl moiety without considering the number of carbon atoms in the substituent(s). For example, a phenyl group substituted with a butyl group at the para-position corresponds to a C<NUM> aryl group substituted with a C<NUM> butyl group.

As used herein, the expression "form a ring with an adjacent substituent" means that the corresponding substituent combines with an adjacent substituent to form a substituted or unsubstituted alicyclic or aromatic ring and the term "adjacent substituent" may mean a substituent on an atom directly attached to an atom substituted with the corresponding substituent, a substituent disposed sterically closest to the corresponding substituent or another substituent on an atom substituted with the corresponding substituent. For example, two substituents substituted at the ortho position of a benzene ring or two substituents on the same carbon in an aliphatic ring may be considered "adjacent" to each other.

The alkyl groups may be straight or branched. The number of carbon atoms in the alkyl groups is not particularly limited but is preferably <NUM> to <NUM>. Specific examples of the alkyl groups include, but are not limited to, methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, <NUM>-methylbutyl, <NUM>-ethylbutyl, pentyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, n-hexyl, <NUM>-methylpentyl, <NUM>-methylpentyl, <NUM>-methyl-<NUM>-pentyl, <NUM>,<NUM>-dimethylbutyl, <NUM>-ethylbutyl, heptyl, n-heptyl, <NUM>-methylhexyl, cyclopentylmethyl, cyclohexylmethyl, octyl, n-octyl, tert-octyl, <NUM>-methylheptyl, <NUM>-ethylhexyl, <NUM>-propylpentyl, n-nonyl, <NUM>,<NUM>-dimethylheptyl, <NUM>-ethylpropyl, <NUM>,<NUM>-dimethylpropyl, isohexyl, <NUM>-methylpentyl, <NUM>-methylhexyl, and <NUM>-methylhexyl groups.

The alkenyl group is intended to include straight and branched ones and may be optionally substituted with one or more other substituents. The alkenyl group may be specifically a vinyl, <NUM>-propenyl, isopropenyl, <NUM>-butenyl, <NUM>-butenyl, <NUM>-butenyl, <NUM>-pentenyl, <NUM>-pentenyl, <NUM>-pentenyl, <NUM>-methyl-<NUM>-butenyl, <NUM>,<NUM>-butadienyl, allyl, <NUM>-phenylvinyl-<NUM>-yl, <NUM>-phenylvinyl-<NUM>-yl, <NUM>,<NUM>-diphenylvinyl-<NUM>-yl, <NUM>-phenyl-<NUM>-(naphthyl-<NUM>-yl)vinyl-<NUM>-yl, <NUM>,<NUM>-bis(diphenyl-<NUM>-yl)vinyl-<NUM>-yl, stilbenyl or styrenyl group but is not limited thereto.

The alkynyl group is intended to include straight and branched ones and may be optionally substituted with one or more other substituents. The alkynyl group may be, for example, ethynyl or <NUM>-propynyl but is not limited thereto.

The cycloalkyl group is intended to include monocyclic and polycyclic ones and may be optionally substituted with one or more other substituents. As used herein, the term "polycyclic" means that the cycloalkyl group may be directly attached or fused to one or more other cyclic groups. The other cyclic groups may be cycloalkyl groups and other examples thereof include heterocycloalkyl, aryl, and heteroaryl groups. The cycloalkyl group may be specifically a cyclopropyl, cyclobutyl, cyclopentyl, <NUM>-methylcyclopentyl, <NUM>,<NUM>-dimethylcyclopentyl, cyclohexyl, <NUM>-methylcyclohexyl, <NUM>-methylcyclohexyl, <NUM>,<NUM>-dimethylcyclohexyl, <NUM>,<NUM>,<NUM>-trimethylcyclohexyl, <NUM>-tert-butylcyclohexyl, cycloheptyl or cyclooctyl group but is not limited thereto.

The heterocycloalkyl group is intended to include monocyclic and polycyclic ones interrupted by a heteroatom such as O, S, Se, N or Si and may be optionally substituted with one or more other substituents. As used herein, the term "polycyclic" means that the heterocycloalkyl group may be directly attached or fused to one or more other cyclic groups. The other cyclic groups may be heterocycloalkyl groups and other examples thereof include cycloalkyl, aryl, and heteroaryl groups.

The aryl groups may be monocyclic or polycyclic ones. Examples of the monocyclic aryl groups include, but are not limited to, phenyl, biphenyl, terphenyl, and stilbenyl groups. Examples of the polycyclic aryl groups include naphthyl, anthracenyl, phenanthrenyl, pyrenyl, perylenyl, tetracenyl, chrysenyl, fluorenyl, acenaphathcenyl, triphenylene, and fluoranthrene groups but the scope of the present invention is not limited thereto.

The heteroaryl groups refer to heterocyclic groups interrupted by one or more heteroatoms. Examples of the heteroaryl groups include, but are not limited to, thiophene, furan, pyrrole, imidazole, triazole, oxazole, oxadiazole, triazole, pyridyl, bipyridyl, pyrimidyl, triazine, triazole, acridyl, pyridazine, pyrazinyl, quinolinyl, quinazoline, quinoxalinyl, phthalazinyl, pyridopyrimidinyl, pyridopyrazinyl, pyrazinopyrazinyl, isoquinoline, indole, carbazole, benzoxazole, benzimidazole, benzothiazole, benzocarbazole, benzothiophene, dibenzothiophene, benzofuranyl, dibenzofuranyl, phenanthroline, thiazolyl, isoxazolyl, oxadiazolyl, thiadiazolyl, benzothiazolyl, and phenothiazinyl groups.

The alkoxy group may be specifically a methoxy, ethoxy, propoxy, isobutyloxy, sec-butyloxy, pentyloxy, iso-amyloxy or hexyloxy group but is not limited thereto.

The silyl group is intended to include alkyl-substituted silyl groups and aryl-substituted silyl groups. Specific examples of such silyl groups include trimethylsilyl, triethylsilyl, triphenylsilyl, trimethoxysilyl, dimethoxyphenylsilyl, diphenylmethylsilyl, diphenylvinylsilyl, methylcyclobutylsilyl, and dimethylfurylsilyl.

The amine groups may be, for example, -NH<NUM>, alkylamine groups, and heteroarylamine groups. The arylamine groups are aryl-substituted amine groups and the alkylamine groups are alkyl-substituted amine groups. Examples of the arylamine groups include substituted or unsubstituted monoarylamine groups, substituted or unsubstituted diarylamine groups, and substituted or unsubstituted triarylamine groups. The aryl moieties in the arylamine groups may be monocyclic or polycyclic ones. The arylamine groups may include two or more aryl moieties. In this case, the aryl moieties may be all either monocyclic or polycyclic ones. Alternatively, the arylamine groups may include one or more monocyclic aryl moieties and one or more polycyclic aryl moieties. The aryl moieties in the arylamine groups may be selected from those exemplified above for the aryl groups.

The aryl moieties in the aryloxy group and the arylthioxy group are the same as those described above for the aryl groups. Specific examples of the aryloxy groups include, but are not limited to, phenoxy, p-tolyloxy, m-tolyloxy, <NUM>,<NUM>-dimethylphenoxy, <NUM>,<NUM>,<NUM>-trimethylphenoxy, p-tert-butylphenoxy, <NUM>-biphenyloxy, <NUM>-biphenyloxy, <NUM>-naphthyloxy, <NUM>-naphthyloxy, <NUM>-methyl-<NUM>-naphthyloxy, <NUM>-methyl-<NUM>-naphthyloxy, <NUM>-anthryloxy, <NUM>-anthryloxy, <NUM>-anthryloxy, <NUM>-phenanthryloxy, <NUM>-phenanthryloxy, and <NUM>-phenanthryloxy groups. The arylthioxy group may be, for example, a phenylthioxy, <NUM>-methylphenylthioxy or <NUM>-tert-butylphenylthioxy group but is not limited thereto.

The halogen group may be, for example, fluorine, chlorine, bromine or iodine.

The polycyclic aromatic derivative of the present invention is selected from the following compounds <NUM> to <NUM>:
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>.

The specific substituents in Formula A can be clearly seen from the structures of the compounds <NUM> to <NUM>.

As can be seen from the above specific compounds, the polycyclic aromatic derivatives of the present invention contain B, P or P=O and have a polycyclic aromatic structure. The introduction of substituents into the polycyclic aromatic structure enables the synthesis of organic light emitting materials with inherent characteristics of the substituents. For example, the substituents are designed for use in materials for hole injecting layers, hole transport layers, light emitting layers, electron transport layers, electron injecting layers, electron blocking layers, and hole blocking layers of organic electroluminescent devices. This introduction meets the requirements of materials for the organic layers, making the organic electroluminescent devices highly efficient.

A further aspect of the present invention is directed to an organic electroluminescent device including a first electrode, a second electrode, and one or more organic layers interposed between the first and second electrodes wherein one of the organic layers includes at least one of the organic electroluminescent compounds of the present invention.

That is, according to one embodiment of the present invention, the organic electroluminescent device has a structure in which one or more organic layers are arranged between a first electrode and a second electrode. The organic electroluminescent device of the present invention may be fabricated by a suitable method known in the art using suitable materials known in the art, except that the organic electroluminescent compound of the present invention is used to form the corresponding organic layer.

The organic layers of the organic electroluminescent device according to the present invention may form a monolayer structure. Alternatively, the organic layers may have a multilayer stack structure. For example, the organic layers may have a structure including a hole injecting layer, a hole transport layer, a hole blocking layer, a light emitting layer, an electron blocking layer, an electron transport layer, and an electron injecting layer but are not limited to this structure. The number of the organic layers is not limited and may be increased or decreased. Preferred structures of the organic layers of the organic electroluminescent device according to the present invention will be explained in more detail in the Examples section that follows.

The organic electroluminescent device of the present invention will be described in more detail with reference to exemplary embodiments.

The organic electroluminescent device of the present invention includes an anode, a hole transport layer, a light emitting layer, an electron transport layer, and a cathode. The organic electroluminescent device of the present invention may optionally further include a hole injecting layer between the anode and the hole transport layer and an electron injecting layer between the electron transport layer and the cathode. If necessary, the organic electroluminescent device of the present invention may further include one or two intermediate layers such as a hole blocking layer or an electron blocking layer. The organic electroluminescent device of the present invention may further include one or more organic layers that have various functions depending on the desired characteristics of the device.

The light emitting layer of the organic electroluminescent device according to the present invention includes, as a host compound, an anthracene derivative represented by Formula C:
<CHM>
wherein R<NUM> to R<NUM> are identical to or different from each other and are as defined for R<NUM> to R<NUM> in Formula A, Ar<NUM> and Ar<NUM> are identical to or different from each other and are each independently selected from hydrogen, deuterium, substituted or unsubstituted C<NUM>-C<NUM> alkyl, substituted or unsubstituted C<NUM>-C<NUM> aryl, substituted or unsubstituted C<NUM>-C<NUM> alkenyl, substituted or unsubstituted C<NUM>-C<NUM> alkynyl, substituted or unsubstituted C<NUM>-C<NUM> cycloalkyl, substituted or unsubstituted C<NUM>-C<NUM> cycloalkenyl, substituted or unsubstituted C<NUM>-C<NUM> heteroaryl, substituted or unsubstituted C<NUM>-C<NUM> heterocycloalkyl, substituted or unsubstituted C<NUM>-C<NUM> alkoxy, substituted or unsubstituted C<NUM>-C<NUM> aryloxy, substituted or unsubstituted C<NUM>-C<NUM> alkylthioxy, substituted or unsubstituted C<NUM>-C<NUM> arylthioxy, substituted or unsubstituted C<NUM>-C<NUM> alkylamine, substituted or unsubstituted C<NUM>-C<NUM> arylamine, substituted or unsubstituted C<NUM>-C<NUM> alkylsilyl, and substituted or unsubstituted C<NUM>-C<NUM> arylsilyl, L<NUM> is a single bond or is selected from substituted or unsubstituted C<NUM>-C<NUM> arylene and substituted or unsubstituted C<NUM>-C<NUM> heteroarylene, preferably a single bond or substituted or unsubstituted C<NUM>-C<NUM> arylene, and k is an integer from <NUM> to <NUM>, provided that when k is <NUM> or more, the linkers L<NUM> are identical to or different from each other.

Ar<NUM> in Formula C is represented by Formula C-<NUM>:
<CHM>
wherein R<NUM> to R<NUM> are identical to or different from each other and are as defined for R<NUM> to R<NUM> in Formula A and each of R<NUM> to R<NUM> is optionally bonded to an adjacent substituent to form a saturated or unsaturated ring.

The compound of Formula C employed in the organic electroluminescent device of the present invention may be specifically selected from the compounds of Formulae C1 to C48:
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>.

A specific structure of the organic electroluminescent device according to the present invention, a method for fabricating the device, and materials for the organic layers will be described below.

First, an anode material is coated on a substrate to form an anode. The substrate may be any of those used in general electroluminescent devices. The substrate is preferably an organic substrate or a transparent plastic substrate that is excellent in transparency, surface smoothness, ease of handling, and waterproofness. A highly transparent and conductive metal oxide such as indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO<NUM>) or zinc oxide (ZnO) is used as the anode material.

A hole injecting material is coated on the anode by vacuum thermal evaporation or spin coating to form a hole injecting layer. Then, a hole transport material is coated on the hole injecting layer by vacuum thermal evaporation or spin coating to form a hole transport layer.

The hole injecting material is not specially limited as long as it is usually used in the art. Specific examples of such materials include <NUM>,<NUM>',<NUM>"-tris(<NUM>-naphthylphenyl-phenylamino)triphenylamine (<NUM>-TNATA), N,N'-di(<NUM>-naphthyl)-N,N'-diphenylbenzidine (NPD), N,N'-diphenyl-N,N'-bis(<NUM>-methylphenyl)-<NUM>,<NUM>'-biphenyl-<NUM>,<NUM>'-diamine (TPD), and N,N'-diphenyl-N,N'-bis(<NUM>-(phenyl-m-tolylamino)phenyl)biphenyl-<NUM>,<NUM>'-diamine (DNTPD).

The hole transport material is not specially limited as long as it is commonly used in the art. Examples of such materials include N,N'-bis(<NUM>-methylphenyl)-N,N'-diphenyl-(<NUM>,<NUM>-biphenyl)-<NUM>,<NUM>'-diamine (TPD) and N,N'-di(naphthalen-<NUM>-yl)-N,N'-diphenylbenzidine (α-NPD).

Subsequently, a hole auxiliary layer and a light emitting layer are sequentially formed on the hole transport layer. A hole blocking layer may be optionally formed on the light emitting layer by vacuum thermal evaporation or spin coating. The hole blocking layer is formed as a thin film and blocks holes from entering a cathode through the organic light emitting layer. This role of the hole blocking layer prevents the lifetime and efficiency of the device from deteriorating. A material having a very low highest occupied molecular orbital (HOMO) energy level is used for the hole blocking layer. The hole blocking material is not particularly limited as long as it can transport electrons and has a higher ionization potential than the light emitting compound. Representative examples of suitable hole blocking materials include BAlq, BCP, and TPBI.

Examples of materials for the hole blocking layer include, but are not limited to, BAlq, BCP, Bphen, TPBI, NTAZ, BeBq<NUM>, OXD-<NUM>, and Liq.

An electron transport layer is deposited on the hole blocking layer by vacuum thermal evaporation or spin coating, and an electron injecting layer is formed thereon. A cathode metal is deposited on the electron injecting layer by vacuum thermal evaporation to form a cathode, completing the fabrication of the organic electroluminescent device.

For example, lithium (Li), magnesium (Mg), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In) or magnesium-silver (Mg-Ag) may be used as the metal for the formation of the cathode. The organic electroluminescent device may be of top emission type. In this case, a transmissive material such as ITO or IZO may be used to form the cathode.

A material for the electron transport layer functions to stably transport electrons injected from the cathode. The electron transport material may be any of those known in the art and examples thereof include, but are not limited to, quinoline derivatives, particularly tris(<NUM>-quinolinolate)aluminum (Alq3), TAZ, Balq, beryllium bis(benzoquinolin-<NUM>-olate (Bebq2), ADN, and oxadiazole derivatives such as PBD, BMD, and BND.

Each of the organic layers can be formed by a monomolecular deposition or solution process. According to the monomolecular deposition process, the material for each layer is evaporated into a thin film under heat and vacuum or reduced pressure. According to the solution process, the material for each layer is mixed with a suitable solvent, and then the mixture is formed into a thin film by a suitable method such as ink-jet printing, roll-to-roll coating, screen printing, spray coating, dip coating or spin coating.

The organic electroluminescent device of the present invention can be used in a display or lighting system selected from flat panel displays, flexible displays, monochromatic flat panel lighting systems, white flat panel lighting systems, flexible monochromatic lighting systems, and flexible white lighting systems.

The present invention will be explained more specifically with reference to the following examples. However, it will be obvious to those skilled in the art that these examples are in no way intended to limit the scope of the invention.

<NUM>-a was synthesized by Reaction <NUM>.

<NUM> (<NUM> mmol) of <NUM>,<NUM>-dibromo-<NUM>-methoxybenzene, <NUM> (<NUM> mmol) of diphenylamine, <NUM> (<NUM> mmol) of sodium tert-butoxide, <NUM> (<NUM> mmol) of bis(tri-tert-butylphosphine)Pd(<NUM>), and <NUM> of toluene were placed in a <NUM> reactor. The mixture was stirred under reflux for <NUM>. After completion of the reaction, the reaction solution was left standing for layer separation. The organic layer was concentrated under reduced pressure and separated by column chromatography to afford <NUM> (yield <NUM>%) of <NUM>-a.

<NUM>-b was synthesized by Reaction <NUM>.

<NUM> (<NUM> mmol) of <NUM>-bromobenzothiophene, <NUM> (<NUM> mmol) of aniline, <NUM> (<NUM> mmol) of palladium acetate, <NUM> (<NUM> mmol) of sodium tert-butoxide, <NUM> (<NUM> mmol) of bis(diphenylphosphino)-<NUM>,<NUM>'-binaphthyl, and <NUM> of toluene were placed in a <NUM> reactor. The mixture was stirred under reflux for <NUM>. After completion of the reaction, the reaction solution was filtered. The filtrate was concentrated and separated by column chromatography to afford <NUM> (yield <NUM>%) of <NUM>-b.

<NUM>-c was synthesized by Reaction <NUM>.

<NUM> (<NUM> mmol) of <NUM>-a, <NUM> (<NUM> mmol) of <NUM>-b, <NUM> (<NUM> mmol) of sodium tert-butoxide, <NUM> (<NUM> mmol) of bis(tri-tert-butylphosphine)Pd(<NUM>), and <NUM> of toluene were placed in a <NUM> reactor. The mixture was stirred under reflux for <NUM>. After completion of the reaction, the reaction solution was left standing for layer separation. The organic layer was concentrated under reduced pressure and separated by column chromatography to afford <NUM> (yield <NUM>%) of <NUM>-c.

<NUM>-d was synthesized by Reaction <NUM>.

<NUM> (<NUM> mmol) of <NUM>-c, <NUM> of acetic acid, and <NUM> of hydrogen bromide were placed in a dry <NUM> reactor. The mixture was stirred under reflux for <NUM>. After completion of the reaction, the reaction solution was precipitated in excess water. The solid was collected by filtration and separated by column chromatography to afford <NUM> (yield <NUM>%) of <NUM>-d.

<NUM>-e was synthesized by Reaction <NUM>.

<NUM> (<NUM> mmol) of <NUM>-d, <NUM> (<NUM> mmol) of potassium carbonate, <NUM> (<NUM> mmol) of <NUM>-bromo-<NUM>-fluorobenzene, and <NUM> of <NUM>-methyl-<NUM>-pyrrolidone were placed in a <NUM> reactor. The mixture was stirred under reflux for <NUM>. After completion of the reaction, the reaction solution was precipitated in excess water. The solid was collected by filtration and separated by column chromatography to afford <NUM> (yield <NUM>%) of <NUM>-e.

<NUM>-f was synthesized by Reaction <NUM>.

<NUM> (<NUM> mmol) of <NUM>,<NUM>-dibromo-<NUM>-chlorobenzene, <NUM> (<NUM> mmol) of diphenylamine, <NUM> (<NUM> mmol) of sodium tert-butoxide, <NUM> (<NUM> mmol) of bis(tri-tert-butylphosphine)Pd(<NUM>), and <NUM> of toluene were placed in a <NUM> reactor. The mixture was stirred under reflux for <NUM>. After completion of the reaction, the reaction solution was left standing for layer separation. The organic layer was concentrated under reduced pressure and separated by column chromatography to afford <NUM> (yield <NUM>%) of <NUM>-f.

<NUM>-g was synthesized by Reaction <NUM>. <CHM>
<CHM>.

<NUM> (<NUM> mmol) of <NUM>-f, <NUM> (<NUM> mmol) of aniline, <NUM> (<NUM> mmol) of sodium tert-butoxide, <NUM> (<NUM> mmol) of bis(tri-tert-butylphosphine)Pd(<NUM>), and <NUM> of toluene were placed in a <NUM> reactor. The mixture was stirred under reflux for <NUM>. After completion of the reaction, the reaction solution was left standing for layer separation. The organic layer was concentrated under reduced pressure and separated by column chromatography to afford <NUM> (yield <NUM>%) of <NUM>-g.

<NUM>-h was synthesized by Reaction <NUM>.

<NUM> (<NUM> mmol) of <NUM>-e, <NUM> (<NUM> mmol) of <NUM>-g, <NUM> (<NUM> mmol) of sodium tert-butoxide, <NUM> (<NUM> mmol) of bis (tri-tert-butylphosphine)Pd(<NUM>), and <NUM> of toluene were placed in a <NUM> reactor. The mixture was stirred under reflux for <NUM>. After completion of the reaction, the reaction solution was left standing for layer separation. The organic layer was concentrated under reduced pressure and separated by column chromatography to afford <NUM> (yield <NUM>%) of <NUM>-h.

Compound <NUM> was synthesized by Reaction <NUM>.

<NUM> (<NUM> mmol) of <NUM>-h and <NUM> of dichlorobenzene were placed in a <NUM> reactor, and <NUM> (<NUM> mmol) of boron tribromide was added dropwise thereto at <NUM>. The mixture was stirred at room temperature for <NUM> and at <NUM> for <NUM>. After completion of the reaction, an aqueous sodium acetate solution was added to the reaction mixture at room temperature. The resulting mixture was stirred and extracted with ethyl acetate. The organic layer was concentrated and separated by column chromatography to afford <NUM> (yield <NUM>%) of Compound <NUM>.

<NUM> (yield <NUM>%) of <NUM>-a was synthesized in the same manner as in Synthesis Example <NUM>-<NUM>, except that <NUM>-bromo-<NUM>-chloro-N,N-diphenylaniline was used instead of <NUM>-a.

<NUM> (yield <NUM>%) of <NUM>-b was synthesized in the same manner as in Synthesis Example <NUM>-<NUM>, except that <NUM>-a was used instead of <NUM>-f.

<NUM> (yield <NUM>%) of <NUM>-c was synthesized in the same manner as in Synthesis Example <NUM>-<NUM>, except that <NUM>-b was used instead of <NUM>-g.

<NUM> (yield <NUM>%) of Compound <NUM> was synthesized in the same manner as in Synthesis Example <NUM>-<NUM>, except that <NUM>-c was used instead of <NUM>-h.

<NUM> (yield <NUM>%) of <NUM>-a was synthesized in the same manner as in Synthesis Example <NUM>-<NUM>, except that <NUM>,<NUM>-dibromothiophene was used instead of <NUM>-bromo-<NUM>-fluorobenzene.

<NUM> (yield <NUM>%) of <NUM>-b was synthesized in the same manner as in Synthesis Example <NUM>-<NUM>, except that <NUM>-a was used instead of <NUM>-e.

<NUM> (yield <NUM>%) of Compound <NUM> was synthesized in the same manner as in Synthesis Example <NUM>-<NUM>, except that <NUM>-b was used instead of <NUM>-h.

<NUM> (yield <NUM>%) of <NUM>-a was synthesized in the same manner as in Synthesis Example <NUM>-<NUM>, except that <NUM>-bromo-<NUM>-chloro-N,N-diphenylaniline and N-phenylbenzofuran-<NUM>-amine were used instead of <NUM>-a and <NUM>-b.

<NUM> (yield <NUM>%) of <NUM>-a was synthesized in the same manner as in Synthesis Example <NUM>-<NUM>, except that N-phenylbenzofuran-<NUM>-amine and <NUM>-bromo-<NUM>-fluorobenzene were used instead of <NUM>-a and <NUM>-b.

<NUM> (yield <NUM>%) of <NUM>-b was synthesized in the same manner as in Synthesis Example <NUM>-<NUM>, except that <NUM>,<NUM>-dihydroxybenzene and <NUM>-a were used instead of <NUM>-bromo-<NUM>-fluorobenzene and <NUM>-d.

Compound <NUM> was synthesized by Reaction <NUM>. <CHM>
<CHM>.

ITO glass was patterned to have a light emitting area of <NUM> × <NUM>, followed by cleaning. After the cleaned ITO glass was mounted in a vacuum chamber, the base pressure was adjusted to <NUM> × <NUM>-<NUM> pascals (<NUM> × <NUM>-<NUM> torr).

DNTPD (<NUM>Å) and the compound represented by Formula H (<NUM>Å) were deposited in this order on the ITO. A mixture of the compound represented by BH1 as a host and the inventive compound (<NUM> wt%) shown in Table <NUM> was used to form a <NUM>Å thick light emitting layer. Thereafter, a mixture of the compound represented by Formula E-<NUM> and the compound represented by Formula E-<NUM> in a ratio of <NUM>:<NUM> was used to form a <NUM>Å thick electron transport layer on the light emitting layer. The compound represented by Formula E-<NUM> was used to form a <NUM>Å thick electron injecting layer on the electron transport layer. Al was used to form a <NUM>Å thick Al electrode on the electron injecting layer, completing the fabrication of an organic electroluminescent device. The luminescent properties of the organic electroluminescent device were measured at <NUM> mA. <CHM>
<CHM>.

Organic electroluminescent devices were fabricated in the same manner as in Examples <NUM>-<NUM>, except that BD1 or BD2 was used instead of the inventive compound. The luminescent properties of the organic electroluminescent devices were measured at <NUM> mA. The structures of BD1 and BD2 are as follow:
<CHM>.

The organic electroluminescent devices of Examples <NUM>-<NUM> and Comparative Examples <NUM>-<NUM> were measured for driving voltage and external quantum efficiency. The results are shown in Table <NUM>.

As can be seen from the results in Table <NUM>, the organic electroluminescent devices of Examples <NUM>-<NUM>, each of which employed the inventive compound, had high luminous efficiencies compared to the devices of Comparative Examples <NUM> and <NUM>, which employed BD1 and BD2, respectively.

Claim 1:
A polycyclic aromatic derivative selected from the following compounds <NUM> to <NUM>:
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