KR20100007639A - Novel phenyl-fluorene derivatives and organic electroluminescent device comprising the same - Google Patents

Abstract

PURPOSE: A phenyl-fluorene derivative is provided to realize excellent hole transport ability, high the luminous efficiency and luminescent brightness, and long lifetime, thereby improving driving voltage, luminous efficiency and lifetime property of an organic electroluminescence device. CONSTITUTION: A phenyl-fluorene derivative has a structure represented by chemical formula 1. In chemical formula 1, R^1 and R^2 are independently hydrogen, C1-30 alkyl or cycloalkyl group containing or not containing at least one hetero atom selected from the group consisting of S, N, O, P and Si, C1-10 alkenyl, aryloxy or arylalkyl- substituted aryl group; an aryl group C1-10 alkenyl, aryloxy or arylalkyl substituted with containing or not containing at least one hetero waters.

Description

Novel phenyl-fluorene derivative and organic electroluminescent device comprising the same {NOVEL PHENYL-FLUORENE DERIVATIVES AND ORGANIC ELECTROLUMINESCENT DEVICE COMPRISING THE SAME}

The present invention relates to an organic electroluminescent device comprising multiple organic layers between an anode and a cathode.

Recently, the organic electroluminescent device capable of low voltage driving with self-luminous type has better viewing angle, contrast ratio, etc. than liquid crystal display (LCD), which is the mainstream of flat panel display devices, and is light and thin because no backlight is required. It is advantageous in terms of power consumption, and has a wide range of color reproduction, attracting attention as a next generation display device.

In general, an organic electroluminescent device has a structure including a cathode (electron injection electrode) and an anode (hole injection electrode), and an organic layer between the two electrodes. In this case, the organic layer may be a hole injection layer (HIL), a hole transport layer (HTL), an electron transport layer (ETL) and / or an electron injection layer, in addition to the light emitting layer (EML). And an electron injection layer (EIL), and may further include an electron blocking layer (EBL) or a hole blocking layer (HBL) due to light emission characteristics of the light emitting layer. A general organic electroluminescent device has a structure laminated in the order of anode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer / cathode.

When an electric field is applied to the organic electroluminescent device having such a structure, holes are injected from the anode, electrons are injected from the cathode, and holes and electrons are recombined in the emission layer through the hole transport layer and the electron transport layer, respectively, thereby emitting light. form exitons). The formed light exciton emits light while transitioning to the ground state. In order to increase the efficiency and stability of the light emitting state, the light emitting dye (dopant) may be doped into the light emitting layer (host).

International Publication Nos. WO04 / 074399, Japanese Patent Laid-Open Nos. 2005-325097, 2007-063285, 2007-137795, 2007-142011, 2007-191465 and 2008-050337, And Japanese Patent Nos. 3,884,557, 3,902,993, 3,983,215 and 4,059,834 disclose compounds containing fluorene or phenyl-fluorene structures as materials used in the organic layers of organic electroluminescent devices.

However, in the case of an organic electroluminescent device using an arylamine-based compound including a fluorene structure known to date as a hole transport layer material, there are many difficulties in practical use due to high driving voltage, low efficiency and short lifespan.

Accordingly, efforts have been made to develop organic electroluminescent devices having low voltage driving, high efficiency and long life using various kinds of materials having arylamine-based structures including fluorene structures.

Accordingly, an object of the present invention is to provide a novel phenyl-fluorene derivative and an organic electroluminescent device using the same, which have excellent hole transporting ability and can significantly improve driving voltage, luminous efficiency, and lifetime characteristics of the organic electroluminescent device.

In order to achieve the above object, the present invention provides a compound represented by the following Chemical Formula 1:

Formula 1

Where

R ¹ And Each R ² is independently hydrogen; C _1-30 alkyl or cycloalkyl group with or without one or more heteroatoms selected from the group consisting of S, N, O, P and Si; Aryl groups substituted with C _1-10 alkenyl, aryloxy or arylalkyl containing or without one or more heteroatoms selected from the group consisting of S, N, O, P and Si; Or C _5-30 containing or without one or more heteroatoms selected from the group consisting of S, N, O, P and Si Aryl group, wherein R ¹ and R ² may be substituted with F or Cl, Can combine with each other to form one or more rings,

Ar ¹ to Ar ⁴ are each independently a C _1-50 aryl group; Polycyclic aromatic compounds; Or C _1-30 containing or without one or more hetero atoms selected from the group consisting of S, N, O, P and Si It is an aryl group containing an alkyl group.

The present invention also provides an organic electroluminescent device comprising the compound of Formula 1 in the hole transport layer.

The organic electroluminescent device including the compound of the present invention in the hole transport layer or the light emitting layer can significantly improve driving voltage, luminous efficiency and lifespan characteristics.

Hereinafter, the present invention will be described in more detail.

Preferably, R ¹ And Each R ² is independently hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, s-butyl, t-butyl, pentyl, neopentyl, hexyl, heptyl, octyl, methyloxy, ethyloxy, trichloromethyl , Trifluoromethyl, triphenylmethyl, cyclopentyl, cyclohexyl, phenyl, 2-phenylisopropyl, styryl, benzyl, α-phenoxybenzyl, α, α-dimethylbenzyl, α, α-phenylmethylbenzyl , α, α-ditrifluoromethylbenzyl, α, α-benzyloxybenzyl, 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 4-ethylphenyl, 1-naphthyl, 2-naphthyl, 4-methyl Naphthyl, 5-methylnaphthyl, biphenyl, 4-methylbiphenyl, 4-ethylbiphenyl, 4-cyclohexylbiphenyl, terphenyl, 3,5-dichlorophenyl, anthryl, pyrenyl, benzofuran 1, benzothiophenyl, benzothiazolyl, quinoline, isoquinoline, fluorenyl or phenanthryl, wherein R ¹ and R ² is It may combine with each other to form at least one ring.

Also preferably, Ar ¹ to Ar ⁴ are each independently phenyl, 1-naphthyl, 2-naphthyl, 4-methylnaphthyl, 5-methylnaphthyl, biphenyl, 4-methylbiphenyl, 4-ethyl Biphenyl, 4-cyclohexylbiphenyl, terphenyl, 3,5-dichlorophenyl, anthryl, pyrenyl, benzofuranyl, benzothiophenyl, benzothiazolyl, quinoline, isoquinoline, fluorenyl or It is phenanthryl.

Most preferably, R ¹ And Each R ² is independently methyl, ethyl, propyl, butyl, methyloxy, trifluoromethyl, cyclohexyl, phenyl, styryl, benzyl, 1-naphthyl, 2-naphthyl, biphenyl, terphenyl, anthryl Or fluorenyl, and Ar ¹ to Ar ⁴ are each independently phenyl, 1-naphthyl, 2-naphthyl, biphenyl, terphenyl, anthryl, pyrenyl, quinoline, fluorenyl or phenanthryl.

Specific examples of the compound represented by Chemical Formula 1 include, but are not limited to, compounds represented by the following Compounds 1 to 65:

The compound of formula 1 according to the present invention can be prepared by the aromatic amine compound and the aromatic halogen compound through the well-known Buchwald-Hartwig amine reaction in the carbon-nitrogen coupling reaction. For example, as shown in Scheme 1, the compound of Formula 1 may be prepared.

Where

R ¹ and R ² are as defined above,

X is I or Br.

The present invention also provides an organic electroluminescent device comprising the compound of Formula 1 in the hole transport layer.

The organic electroluminescent device of the present invention has a structure in which an anode (hole injection electrode), a hole transport layer (HTL) containing a compound of Formula 1, and a cathode (electron injection electrode) are sequentially stacked, in particular between an anode and a light emitting layer. A hole injection layer (HIL), a hole transport layer (HTL) or an electron blocking layer (EBL), and an electron transport layer (ETL), an electron injection layer (EIL) or a hole blocking layer (HBL) between the cathode and the light emitting layer It is preferable.

1 illustrates a structure of an organic electroluminescent device stacked on a substrate in the order of anode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer / cathode.

First, a positive electrode is coated on a surface of a substrate by a conventional method to form a positive electrode. At this time, the substrate used is preferably a glass substrate or a transparent plastic substrate excellent in transparency, surface smoothness, ease of handling and waterproofness. In addition, as the material for the anode, indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO ₂ ), zinc oxide (ZnO), and the like, which are transparent and have excellent conductivity, may be used.

Next, a hole injection layer is formed on the surface of the anode by vacuum thermal evaporation or spin coating of the hole injection layer material in a conventional manner. At this time, the hole injection layer material used is not particularly limited, copper phthalocyanine (CuPc), 4,4 ', 4 "-tris (3-methylphenylamino) triphenylamine (m-MTDATA), 4,4', 4,4'-tris (3-methylphenylamino) phenoxybenzene (m-MTDAPB), starburst amines 4,4 ', 4 "-tris (N-carbazolyl) triphenylamine (TCTA), 4 , 4 ', 4 "-tris (N- (2-naphthyl) -N-phenylamino) -triphenylamine (2T-NATA) or N, N'-di-1- available from Idemitsu Naphthyl-N, N'-bis ((4-diphenylamino) phenyl) benzidine (IDE406) and the like can be used.

A hole transport layer is formed on the surface of the hole injection layer by vacuum thermal evaporation or spin coating of the hole transport layer material in a conventional manner. In this case, the compound of Formula 1 may be used as the hole transport layer material, but is not particularly limited to the hole transport layer material that may be used with the compound of Formula 1, and bis (N- (1-naphthyl-n-phenyl)) Benzidine (α-NPD), N, N'-di (naphthalen-1-yl) -N, N'-diphenyl-benzidine (NPB) or N, N'-diphenyl-N, N'-bis (3 -Methylphenyl) -1,1'-diphenyl-4,4'-diamine (TPD) and the like can be used.

Compound of Formula 1 of the present invention may be included in the hole transport layer in an amount of 30 to 100 mol%.

The light emitting layer is formed on the surface of the hole transport layer by vacuum thermal evaporation or spin coating of a light emitting layer material in a conventional manner. At this time, the host material of the light emitting layer used is not particularly limited, tris (8-quinolinolato) aluminum (Alq ₃ ) or 9,10-di (naphthalen-2-yl) anthracene (ADN) can be used. have.

The dopant used with the light emitting host in the light emitting layer material is not particularly limited, but IDE102, IDE105, BD-052X or C-545T (2,3,6,7-tetra as a green fluorescent dopant) available from Idemitsu as a fluorescent dopant. Hydro-1,1,7,7-tetramethyl-1H, 5H, 11H-10- (2-benzothiazolyl) quinolizino- [9,9a, 1gh] coumarin) as a phosphorescent dopant Phenylpyridine) Iridium (III) (Ir (ppy) ₃ ), Iridium (III) Bis [(4,6-difluorophenyl) pyridinato-N, C-2 '] picolinate (FIrpic) (See Chihaya Adachi etc. Appl. Phys. Lett ., 2001 , 79 , 3082-3084)), platinum (II) octaethyl porphyrin (PtOEP) or TBE002 (Kobiion).

An electron transport layer is formed on the surface of the light emitting layer by vacuum thermal evaporation or spin coating in a conventional manner. In this case, the electron transporting material used is not particularly limited, and tris (8-quinolinolato) aluminum (Alq ₃ ) may be used.

Optionally, (8-hydroxyquinolinolato) lithium (Liq), bis (8-hydroxy-2-methylquinolinolato) -aluminum biphenoxide (BAlq), bathocuproine (BCP) ) Or a hole blocking layer (HBL) material such as LiF by vacuum thermal evaporation and spin coating in a conventional manner to form a hole blocking layer between the light emitting layer and the electron transport layer, and by using a phosphorescent dopant in the light emitting layer, It is possible to prevent the diffusion of holes into the electron transport layer. At this time, the hole blocking layer material used is not particularly limited.

An electron injection layer is formed on the surface of the electron transport layer by vacuum thermal evaporation or spin coating of an electron injection layer (EIL) material in a conventional manner. In this case, the electron injection layer material used is not particularly limited, and materials such as LiF, Liq, Li ₂ O, BaO, NaCl or CsF may be used.

Finally, a negative electrode is formed on the surface of the electron injection layer by vacuum thermal vapor deposition in a conventional manner. In this case, the negative electrode material used is lithium (Li), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium (Mg), magnesium-indium (Mg-In) or magnesium-silver ( Mg-Ag) and the like can be used. In addition, in the case of the front emission organic field device, a transparent cathode through which light may pass may be formed using ITO or IZO.

The organic electroluminescent device according to the present invention may be manufactured in the same order as described above, that is, in the order of anode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer / cathode, and vice versa You may manufacture in order of injection layer / electron transport layer / hole blocking layer / light emitting layer / hole transport layer / hole injection layer / anode.

Hereinafter, the present invention will be described in more detail based on the following examples. However, the following examples are only for illustrating the present invention, and the scope of the present invention is not limited thereto.

Experimental Example 1 Synthesis of Compound 2 of the Present Invention

250 mL three-neck round bottom flask was charged with nitrogen, then 2-bromo-7- (4-bromophenyl) -9,9-dimethyl-9 H -fluorene (10 mmol, 4.28 g), N − Phenylnaphthalen-1-amine (22 mmol, 4.82 g), Pd ₂ (dba) ₃ (0.5 mmol, 0.5 g), P ( t- Bu) ₃ (0.5 mmol, 0.05 g) and t- BuONa (2.10 g, 22 mmol) was added, and 100 ml (0.1 M) of toluene was added thereto as a solvent, and the reaction mixture was stirred at 120 ° C. for 6 hours. The temperature of the reaction solution was lowered to room temperature and extracted with dichloromethane. The obtained extract was dried over anhydrous magnesium sulfate and fractional distillation to remove the solvent. The resulting mixture was separated by silica gel column chromatography (eluent-dichloromethane: n-hexane = 1: 3) to give 6.4 g of the title compound as a yellow solid.

Yield: 91% (6.4 g)

¹ H-NMR (CDCl ₃ , 400 MHz) δ (ppm) 7.93 (d, 1H), 7.75 (s, 1H), 7.63-7.55 (m, 6H), 7.34-7.10 (m, 10H), 7.69 (t, 4H), 6.72 (s, 1H), 6.65-6.43 (m, 11H), 1.63 (s, 6H).

FD-MS: m / z = 705.3 (C ₅₃ H ₄₀ N ₂ = 704.9)

Experimental Example 2 Synthesis of Compound 10 of the Present Invention

N -biphenylnaphthalene-1-amine was synthesized in the same manner as in Experimental Example 1, instead of the N -phenylnaphthalen-1-amine intermediate.

Yield: 83% (7.1 g)

¹ H-NMR (CDCl ₃ , 400 MHz) δ (ppm) 7.91 (d, 1H), 7.79 (s, 1H), 7.69-7.55 (m, 6H), 7.48 (dd, 4H), 7.17-7.34 (m, 20H), 6.76 (s, 1H), 5.59-5.52 (m, 9H), 1.63 (s, 6H).

FD-MS: m / z = 857.42 (C ₆₅ H ₄₈ N ₂ = 857.09)

Experimental Example 3 Synthesis of Compound 24 of the Present Invention

N -fluorenylnaphthalene-1-amine was synthesized in the same manner as in Experimental Example 1, instead of the N -phenylnaphthalen-1-amine intermediate.

Yield: 85% (7.93 g)

¹ H-NMR (CDCl ₃ , 400 MHz) δ (ppm) 7.90 (d, 1H), 7.84 (dd, 2H), 7.71 (s, 1H), 7.66-7.50 (m, 10H), 7.36-7.28 (m, 8H), 7.21 (dd, 2H), 7.15-7.13 (m, 4H), 6.76 (s, 1H), 6.71 (s, 2H), 6.60-6.51 (m, 7H), 1.63 (s, 6H), 1.60 (s, 12H).

FD-MS: m / z = 857.36 (C ₇₁ H ₅₆ N ₂ = 937.22)

Comparative Example: Organic Electroluminescent Device Using NPB as Hole Transport Layer

An organic electroluminescent device was fabricated according to a conventional method using N, N'-di-1-naphthyl-N, N'-diphenylbenzidine (NPB) as the hole transport layer material. First, a 600 Å hole injection layer (hole injection layer material: 2-TNATA), a 300 Å hole transport layer (hole transport layer material: NPB) and a 450 Å thickness BD- are placed on the ITO layer (anode) formed on the glass substrate. Emission layer doped with 052X (Idemitsu Co., Ltd.) 7% (where BD-052X is a blue fluorescent dopant and 9,10-di (naphthalen-2-yl) anthracene (ADN) was used as a light emitting host material), 250 전자 thick electron transport layer (electron transport layer material: tris (8-quinolinolato) aluminum (Alq ₃ )), 10 Å thick electron injection layer (electron injection layer material: LiF) and 1500 Å thick aluminum cathode The organic electroluminescent device was manufactured by vapor deposition.

Example 1 Organic Electroluminescent Device Using Compound 2 of the Present Invention as a Hole Transport Material

An organic electroluminescent device was manufactured according to a conventional method using compound 2 as a hole transport layer material. First, a 600 Å hole injection layer (hole injection layer material: 2-TNATA), a 300 Å hole transport layer (hole transport layer material: compound 2), and a 450 Å BD on the ITO layer (anode) formed on the glass substrate. A light emitting layer doped with -052X (Idemitsu Co., Ltd.) 7% (where BD-052X is a blue fluorescent dopant and 9,10-di (naphthalen-2-yl) anthracene (ADN) was used as a light emitting host material), An electron transport layer (electron transport layer material: Tris (8-quinolinolato) aluminum (Alq ₃ )) of 250 Å thickness, an electron injection layer (electron injection layer material: LiF) 10 Å thick, and an aluminum cathode of 1500 Å thick By sequentially depositing, an organic electroluminescent device was manufactured.

Example 2 Organic Electroluminescent Device Using Compound 10 of the Present Invention as a Hole Transport Material

An organic electroluminescent device was manufactured in the same manner as in Example 1, using Compound 10 as a hole transport material instead of Compound 2.

Example 3 Organic Electroluminescent Device Using Compound 24 of the Present Invention as a Hole Transport Material

An organic electroluminescent device was manufactured in the same manner as in Example 1, using Compound 24 as a hole transport material instead of Compound 2.

For the manufactured organic electroluminescent device, voltage-luminance, current density-luminance, voltage-current density, and luminous efficiency-luminance curves are shown in FIGS. 2 to 5, respectively, and X and Y color coordinates-luminance curves are shown in FIGS. 6 and 7. The electroluminescence spectra and life curves are shown in FIGS. 8 and 9, respectively, and these results are summarized in Table 1 below.

As can be seen from Table 1 and the results of FIGS. 2 to 9, the organic electroluminescent device of the present invention has a lower driving voltage and an electrical stability than the organic electroluminescent device in which a hole transport layer is formed using NPB. It is excellent, it can be seen that not only has a high luminous efficiency and luminous luminance, but also excellent life characteristics.

1 is a cross-sectional view showing the structure of a general organic electroluminescent device,

2 is a voltage-luminance curve for an organic electroluminescent device using the compounds of Compounds 2, 10 and 24 of the present invention as the hole transport layer material,

3 is a current density-luminance curve for an organic electroluminescent device using the compounds of Compounds 2, 10 and 24 of the present invention as the hole transport layer material,

4 is a voltage-current density curve for an organic electroluminescent device using the compounds of Compounds 2, 10 and 24 of the present invention as the hole transport layer material,

FIG. 5 is a light emission efficiency-luminance curve for an organic electroluminescent device using the compounds of Compounds 2, 10 and 24 of the present invention as a hole transport layer material,

FIG. 6 is an X color coordinate-luminance curve for an organic electroluminescent device using the compounds of Compounds 2, 10, and 24 of the present invention as a hole transport layer material,

7 is a Y color coordinate-luminance curve for an organic electroluminescent device using the compounds of Compounds 2, 10, and 24 of the present invention as a hole transport layer material,

8 is an electroluminescence spectrum of an organic electroluminescent device using the compound of compounds 2, 10 and 24 of the present invention as a hole transport layer material,

9 is a lifetime curve for an organic electroluminescent device using the compounds of compounds 2, 10 and 24 of the present invention as the hole transport layer material.

Claims (7)

Phenyl-fluorene derivative represented by the following formula (1): Formula 1

Where R ¹ And Each R ² is independently hydrogen; C _1-30 alkyl or cycloalkyl group with or without one or more heteroatoms selected from the group consisting of S, N, O, P and Si; Aryl groups substituted with C _1-10 alkenyl, aryloxy or arylalkyl containing or without one or more heteroatoms selected from the group consisting of S, N, O, P and Si; Or C _5-30 containing or without one or more hetero atoms selected from the group consisting of S, N, O, P and Si Aryl group, wherein R ¹ and R ² may be substituted with F or Cl, Can combine with each other to form one or more rings, Ar ¹ to Ar ⁴ are each independently a C _1-50 aryl group; Polycyclic aromatic compounds; Or C _1-30 containing or without one or more heteroatoms selected from the group consisting of S, N, O, P and Si It is an aryl group containing an alkyl group. The method of claim 1, R ¹ And Each R ² is independently hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, s-butyl, t-butyl, pentyl, neopentyl, hexyl, heptyl, octyl, methyloxy, ethyloxy, trichloromethyl , Trifluoromethyl, triphenylmethyl, cyclopentyl, cyclohexyl, phenyl, 2-phenylisopropyl, styryl, benzyl, α-phenoxybenzyl, α, α-dimethylbenzyl, α, α-phenylmethylbenzyl , α, α-ditrifluoromethylbenzyl, α, α-benzyloxybenzyl, 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 4-ethylphenyl, 1-naphthyl, 2-naphthyl, 4-methyl Naphthyl, 5-methylnaphthyl, biphenyl, 4-methylbiphenyl, 4-ethylbiphenyl, 4-cyclohexylbiphenyl, terphenyl, 3,5-dichlorophenyl, anthryl, pyrenyl, benzofuran 1, benzothiophenyl, benzothiazolyl, quinoline, isoquinoline, fluorenyl or phenanthryl, Ar ¹ to Ar ⁴ are each independently phenyl, 1-naphthyl, 2-naphthyl, 4-methylnaphthyl, 5-methylnaphthyl, biphenyl, 4-methylbiphenyl, 4-ethylbiphenyl, 4- Cyclohexylbiphenyl, terphenyl, 3,5-dichlorophenyl, anthryl, pyrenyl, benzofuranyl, benzothiophenyl, benzothiazolyl, quinoline, isoquinoline, fluorenyl or phenanthryl, Phenyl-fluorene derivatives. The method of claim 1, R ¹ And Each R ² is independently methyl, ethyl, propyl, butyl, methyloxy, trifluoromethyl, cyclohexyl, phenyl, styryl, benzyl, 1-naphthyl, 2-naphthyl, biphenyl, terphenyl, anthryl Or fluorenyl, Ar ¹ to Ar ⁴ are each independently phenyl, 1-naphthyl, 2-naphthyl, biphenyl, terphenyl, anthryl, pyrenyl, quinoline, fluorenyl or phenanthryl, Phenyl-fluorene derivatives. The method of claim 1, Phenyl-fluorene derivatives selected from the following compounds 1 to 65:

The method of claim 1, The phenyl-fluorene derivatives selected from the following compounds 2, 10 and 24.

Compound 2

Compound 10

Compound 24 An organic electroluminescent device having a hole transport layer between an anode, a cathode and two electrodes, wherein the hole transport layer comprises a phenyl-fluorene derivative according to any one of claims 1 to 4. The method of claim 6, The hole transport layer is an organic electroluminescent device comprising the compound of Formula 1 in an amount of 30 to 100 mol%.

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