KR20090069248A - Organic electroluminescence material and element using the same - Google Patents

Abstract

An organic electroluminescence material is provided to obtain blue light with high chromatic purity and high applicability, and to be applicable to a light source or a display device required for high chromatic purity. An organic electroluminescence material has a structure represented by chemical formula(1). In chemical formula(1), R1~R7 are selected from hydrogen, alkyl group, cycloalkyl group, alkoxy group, cycloalkoxy group and aryloxy group; and A1~A3 are selected from substituted or unsubstituted phenyl group, 5 or 6-membered substituted or unsubstituted heterocyclic groups. The organic electroluminescent device comprises single or multilayered organic layer including a light-emitting layer between a pair of electrodes.

Description

Organic electroluminescent material and element using the same {ORGANIC ELECTROLUMINESCENCE MATERIAL AND ELEMENT USING THE SAME}

The present invention relates to a novel blue light emitting material comprising an anthracene derivative and an organic electroluminescent device (hereinafter referred to as an organic EL device) using the same.

The organic EL device is a self-luminous device that uses an organic compound as a light emitting material, and is capable of emitting light at high speed, which is suitable for displaying moving images, the device structure is simple, and the display panel can be thinned. Has the characteristics of. Since it has such excellent characteristic, organic electroluminescent element is spreading in daily life as a display for a mobile telephone or a vehicle.

Moreover, technology development as an illumination panel light source is progressing, unlike the LED, making surface light emission possible, taking advantage of the thinness and light weight.

The organic EL device achieves high efficiency of light emission by doping a small amount of light emitting material in the host. For this reason, the light emitting material which forms the basis of light emission is an important material in obtaining a high efficiency organic electroluminescent element.

In particular, in order to obtain a white light emitting element having high color rendering property, a light emitting material having high color purity is indispensable for each of the three primary colors of red, green, and blue light.

Among these light emitting materials, for the blue system, for example, anthracene derivatives as shown in the following formulas (1) to (3), distyryl arylene derivatives as shown in the following (Formula 4), and the following (Formula 5) Naphthalene derivatives as shown in the above are known [for example, Japanese Patent Laid-Open No. 11-312588, Japanese Patent Laid-Open No. 2005-222948, Japanese Patent Laid-Open No. 2-247278, J. Shi, et al., Applied Physics Letters, 80 (17), p.3201].

[Formula 1]

[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

However, Japanese Patent Laid-Open Nos. 11-312588, Japanese Patent Laid-Open No. 2005-222948, Japanese Patent Laid-Open No. 2-247278, J. Shi, et al., Applied Physics Letters, 80 (17), p The material described in .3201 emits blue green and light blue colors, and when used as a light emitting material of an organic EL device, blue light emission with high color purity as required by a high color rendering white light emitting device is obtained. It was difficult.

This invention is made | formed in order to solve the said technical subject, Comprising: It aims at providing the novel organic electroluminescent material which shows blue light emission excellent in color purity, and the organic electroluminescent element using the same.

The organic EL material according to the present invention is represented by the following general formula (1).

[Formula 6]

In General Formula (1), R ₁ to R ₇ are selected from hydrogen, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, and an aryloxy group, and may be the same or different groups, and A _{1 to} A ₃ Is selected from a substituted or unsubstituted phenyl group, a 5 or 6 membered substituted or unsubstituted heterocyclic group, and may be the same or different groups.

By using such a compound as an organic EL material, blue light emission useful in a light emitting area and excellent in color purity can be obtained.

Moreover, the organic electroluminescent element which concerns on this invention is an organic electroluminescent element provided with the organic layer of one layer or multiple layers containing a light emitting layer between a pair of electrode, WHEREIN: At least 1 layer of the said organic layer is independent of the said organic EL material. Or containing as a mixture.

By using the organic EL material according to the present invention described above, an element exhibiting blue light emission excellent in color purity can be constituted.

In the organic EL element, at least one layer of the organic layer is preferably a light emitting layer containing the organic EL material as a guest material and a host material.

In addition, the electrode is preferably a transparent conductive thin film formed on a transparent substrate.

As described above, according to the organic EL material according to the present invention, since blue light emission excellent in color purity can be obtained, it becomes possible to provide a high color rendering high efficiency white light emitting element by using this.

Therefore, the organic electroluminescent element which concerns on this invention is a flat panel display for OA computers and wall-mounted televisions which are required the more outstanding color reproducibility recently, and also the backlight light source of a lighting apparatus, a copier, a liquid crystal display, or a meter. Application to a light source, a display panel, a cover, etc. utilizing the characteristics as a surface light-emitting body is expected.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The organic EL material according to the present invention is a compound represented by the general formula (1).

Such anthracene derivative is a novel compound which exhibits blue light emission with excellent color purity, and by using this, a high color rendering white light emitting device can be provided.

Wherein in the formula _(1), R 1 ~R ₇ is selected from hydrogen, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, and an aryloxy group, the same be, respectively, may be different rep. A _{1 to} A ₃ may be selected from a substituted or unsubstituted phenyl group, a 5 or 6 membered substituted or unsubstituted heterocyclic group, and may be the same or different.

Among the substituents, the alkyl group represents, for example, a saturated aliphatic hydrocarbon group such as methyl group, ethyl group, propyl group or butyl group, and may be linear or branched.

The cycloalkyl group represents, for example, saturated alicyclic hydrocarbon groups such as cyclohexyl group, norbornyl group, and adamantyl group, and may be unsubstituted or substituted.

The alkoxy group represents, for example, a saturated aliphatic hydrocarbon group through an ether bond such as a methoxy group, and may be linear or branched.

The cycloalkoxy group represents, for example, a cyclic saturated aliphatic hydrocarbon group via an ether bond such as a cyclohexyl group, and may be unsubstituted or substituted.

The aryloxy group represents, for example, an aromatic hydrocarbon group via an ether bond such as a phenoxy group, and the aromatic hydrocarbon group may be unsubstituted or substituted.

Substituted phenyl group represents a phenyl group substituted with an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, and an aryloxy group.

The heterocyclic group represents a group containing any one of nitrogen, sulfur or oxygen as a cyclic constituent in addition to carbon. For example, oxazole, oxadiazole, thiazole, thiadiazole, furan, furazane, thiophene, pyran, thiopyran, pyrrole, pyrazole, imidazoline, imidazole, pyrazine, pyridine, pyridazine, pyrimidine , Triazole, triazine and the like, and unsubstituted or substituted.

A compound represented by the following, the above general formula (1), costs a specific example of the substituent bonded to any one of A ₁ ~A _3. Further, in the following (Formula 7) substituted or unsubstituted phenyl group, a 5- or 6-membered heterocyclic group of the substituted or unsubstituted shown in, X is a bond in the binding of the anthracene ring position, i.e., A ₁ ~A ₃ Mark the location.

[Formula 7]

In addition, the structure of a specific compound is illustrated below among the compound represented by the said General formula (1).

[Formula 8]

[Formula 9]

[Formula 10]

Among the compounds exemplified in the above formulas (8) to (10), particularly, 2,7,10-triphenylanthracene (hereinafter, abbreviated as TPA) represented by the following formula (11) can be exemplified.

[Formula 11]

The compound represented by the said General formula (1) can be synthesize | combined by the conventionally known synthesis reaction.

For example, first, 4-halogenated phthalic anhydride is used as a raw material, and first, a predetermined benzoyl benzoic acid is obtained by a Friedelcraft acylation reaction with a halogenated benzene. Next, this benzoyl benzoic acid is subjected to dehydration condensation ring closure using a dehydration condensation agent such as chlorine pentoxide, polyphosphoric acid, sulfuric acid or the like (preferably polyphosphoric acid) to synthesize an anthraquinone halide.

The anthraquinone halide is reduced to a metal powder (preferably aluminum powder) in an acidic acid to give an anthrone halide. The resulting anthron halide and nucleophilic reactants such as aryl magnesium bromide and aryl lithium are reacted and acidified with organic acids such as hydrochloric acid and sulfuric acid, and acetic acid, and then led to 2,7-dihalogenated 10-aryl anthracene. . An anthracene derivative represented by the general formula (1) is synthesized by a coupling reaction of a 2,7-dihalogenated 10-aryl anthracene with a corresponding crosscoupling agent using a transition metal catalyst such as Ni or Pd. .

In the above reaction step, by selecting a halogen group during Friedelcraft acylation reaction, the reaction selectivity during coupling reaction using a transition metal catalyst such as Ni and Pd can be obtained, and is asymmetric with the general formula (1). The compound represented can be synthesized. Moreover, also by selecting the nucleophile at the time of nucleophilic reaction, the compound represented by the said General formula (1) which is asymmetric can be synthesize | combined.

Further, by independently selecting the halogen group and the nucleophile, the second, seventh, and tenth positions may each be an independent substituent.

Moreover, the compound represented by the said General formula (1) can also be synthesize | combined using the Diels-Alder reaction.

The organic electroluminescent element which concerns on this invention provided with the layer containing the organic electroluminescent material which exhibits blue light emission excellent in color purity as mentioned above is the structure which laminated | stacked the organic layer of one layer or multiple layers between the electrodes, Specifically, First electrode / light emitting layer / second electrode, first electrode / hole transport layer / light emitting layer / electron transport layer / second electrode, first electrode / hole transport layer / light emitting layer / second electrode, first electrode / light emitting layer / electron transport layer / second Structures, such as an electrode, are mentioned.

Moreover, it is good also as a well-known laminated structure which also contains a hole injection layer, a hole transport light emitting layer, an electron injection layer, an electron transport light emitting layer, etc.

It is preferable that the electrode of the organic electroluminescent element which concerns on this invention is a transparent conductive thin film formed on the transparent substrate.

It is preferable that the said board | substrate becomes a support body of organic electroluminescent element, and when the board | substrate side becomes a light emitting surface, it is preferable to use the transparent board | substrate which has transparency in visible light. It is preferable that it is 80% or more, and, as for light transmittance, it is preferable that it is 85% or more. More preferably, it is 90% or more.

Generally as said transparent substrate, glass substrates, such as optical glass, such as BK7, BaK1, and F2, quartz glass, an alkali free glass, borosilicate glass, aluminosilicate glass, acrylic resins, such as PMMA, polycarbonate, polyether sulfonate Polymer substrates such as polyester such as polystyrene, polyolefin, epoxy resin and polyethylene terephthalate are used.

Although the thickness of the said board | substrate is about 0.1-10 mm normally, it is preferable that it is 0.3-5 mm, and it is more preferable that it is 0.5-2 mm in consideration of mechanical strength, a weight, etc.

Moreover, in this invention, it is preferable that a 1st electrode is provided on the said board | substrate. This first electrode is usually an anode, and is composed of a metal, an alloy, a conductive compound, or the like having a large work function (4 eV or more), but is preferably formed on the transparent substrate as a transparent electrode.

Metal oxides, such as indium tin oxide (ITO), indium zinc oxide, and zinc oxide, are generally used for this transparent electrode, In particular, ITO is used suitably from a viewpoint of transparency, electroconductivity, etc.

It is preferable that it is 80-400 nm, and, as for the film thickness of this transparent electrode, it is more preferable that it is 100-200 nm in order to ensure transparency and electroconductivity.

Formation of an anode is normally performed by sputtering method, a vacuum vapor deposition method, etc., and it is preferable to form as a transparent conductive thin film.

On the other hand, when the said anode is a 1st electrode, the cathode of the 2nd electrode which opposes this is comprised by the metal, alloy, and conductive compound with a small work function (4 eV or less). For example, aluminum, aluminum-lithium alloy, magnesium-silver alloy, etc. are mentioned.

It is preferable that it is 10-500 nm, and, as for the film thickness of the said cathode, it is more preferable that it is 50-200 nm.

The positive electrode and the negative electrode can be formed by forming a film by a commonly used method such as sputtering, ion plating or vapor deposition.

The material used for the said hole injection layer, a hole transport layer, and a hole transporting light emitting layer is not specifically limited, It can select from a well-known thing suitably, and can use.

Specifically, bis (di (p-tolyl) aminophenyl) -1,1-cyclohexane (common name: TAPc), Spiro-TPD (Formula 12), N, N'-diphenyl-N, N'-bis (3-methylphenyl) -1,1'-biphenyl-4,4'-diamine (commonly known as TPD), N, N'-diphenyl-N, N'-bis (1-naphthyl) -1,1 And arylamine derivatives such as' -biphenyl-4,4'-diamine (common name: α-NPD), TPTE (Formula 13), starburstamines (Formula 14), and styrylamines (Formula 15).

[Formula 12]

[Formula 13]

[Formula 14]

[Formula 15]

Further, carbazole derivatives such as bis (N-arylcarbazole) (formula 16), bis (N-alkenylcarbazole), bis (N-alkylcarbazole), pyrazoline derivatives, (Formula 17), and (Formula 17) Styryl compounds, such as 18) and (19), and its derivative (s) can also be used.

[Formula 16]

[Formula 17]

[Formula 18]

[Formula 19]

Or condensed polycyclic aromatic hydrocarbon compounds and derivatives thereof such as anthracene, triphenylene, perylene, naphthalene (Chemical Formula 20), (21), pyrene, coronene, chrysene, naphthacene, tetracene, phenanthrene, Polycyclic compounds, such as paraterphenyl, quaterphenyl, m-phenylene (22), and (23), and derivatives thereof can also be used.

[Formula 20]

[Formula 21]

[Formula 22]

[Formula 23]

As the hole injection layer, the hole transporting layer, or the hole transporting light emitting layer, those obtained by dispersing the organic compound in a polymer, oligomer or dendrimer, or polymerized, oligomerized or dendrimerized may be used.

In addition, so-called π conjugated polymers such as polyparaphenylene vinylene, polyfluorene and derivatives thereof, hole transporting non-conjugated polymers represented by poly (N-vinylcarbazole), and σ conjugated polymers represented by polysilanes, etc. It is available. Moreover, what is called a conjugated oligomer, such as a fluorene oligomer and its derivative (s), etc. can also be used.

As the hole injection layer, in addition to the above materials, conductive polymers such as metal phthalocyanines and metal phthalocyanines, carbon film, fluorocarbon film, polystyrene sulfonic acid (PEDOT-PSS) and polyaniline can also be used.

In addition, organic oxidative dopants such as tetracyanoquinone dimethane and trinitrofluorenone, inorganic oxidative dopants such as vanadium oxide, molybdenum oxide, tungsten oxide, and aluminum oxide are applied to the organic compound to form radical cations to form holes. It can also be used as an injection transport layer. Although the oxidative dopant concentration in this hole injection transport layer is not specifically limited, It is preferable that it is about 0.1 to 99 weight%.

In addition, the material used for an electron injection layer, an electron carrying layer, and an electron carrying luminescent layer is not specifically limited, either, It can select from a well-known thing suitably, and can use.

Specifically, polycyclic compounds such as paraterphenyl, quaterphenyl, m-phenylene (Formula 22), (Formula 23), and derivatives thereof, such as (Formula 17), (Formula 18), and (Formula 19) Styryl compounds and derivatives thereof.

In addition, condensed polycyclic aromatic hydrocarbon compounds such as anthracene, triphenylene, perylene, naphthalene (Formula 20), (pyrene, coronene, chrysene, naphthacene, tetracene, phenanthrene and derivatives thereof, Phenanthroline, vasophenanthroline, vasoprine, phenanthridine, acridine, quinoline, quinoxaline, pyridine (24), pyrimidine, pyrrole, pyrazole, pyridazine, pyrazine, phthalazine, Condensed heterocyclic compounds such as naphthyridine, quinazoline, cinnoline, thiazole, oxadiazole, oxazole, triazine, phenazine, imidazole, benzoxazole, benzothiazole, benzoimidazole, triazole and porphyrin And derivatives thereof.

[Formula 24]

Further, for example, aluminum quinolinol complex, benzoxazole azo complex, benzothiazole azo complex, azomethine zinc complex, europium complex, iridium complex, platinum complex and the like, such as Al, Zn, Be, Ir, Pt , A metal chelate complex material having Tb, Eu, or the like, and having an oxadiazole, thiadiazole, phenylpyridine, quinoline structure as a ligand.

Organosilicon compounds such as sirol and siloxane, derivatives thereof, organoboron compounds such as triaryl boron, derivatives thereof, pentavalent phosphorus compounds such as triaryl phosphoxide, and derivatives thereof.

Moreover, what disperse | distributed the said organic compound in a polymer, an oligomer, or a dendrimer, and polymerized, oligomerized, or dendrimerized can also be used as an electron injection layer, an electron carrying layer, and an electron carrying light emitting layer.

In addition, so-called π conjugated polymers such as polyparaphenylene vinylene, polyfluorene and derivatives thereof, electron transportable non-conjugated polymers represented by polyvinyl oxadiazole, and the like can also be used. Moreover, what is called a conjugated oligomer, such as a fluorene oligomer and its derivative (s), etc. can also be used.

As the constituent material of the electron injection layer, in addition to the above organic compounds, a single metal such as Ba, Ca, Li, Cs, Mg, Sr, W, magnesium fluoride, calcium fluoride, strontium fluoride, barium fluoride, lithium fluoride, cesium fluoride and the like Metal fluorides, alloys of metals such as aluminum lithium alloys, metal oxides such as magnesium oxide, strontium oxide and aluminum oxide, and organic complexes of metals such as polymethyl methacrylate polystyrene sulfonate.

In addition, an organic reducing reductant such as 8-hydroxyquinoline-based Cs or Li-organometallic complex can be applied to the organic compound to form a radical anion and used as an electron injection transport layer.

In addition, a single metal such as Ba, Ca, Li, Cs, Mg, Sr, W, metal oxides such as magnesium oxide, strontium oxide, aluminum oxide, magnesium fluoride, calcium fluoride, strontium fluoride, barium fluoride, lithium fluoride, fluoride Metal salts such as cesium, cesium chloride and strontium chloride and inorganic reducing dopants may be mixed or dispersed to form radical anions and used as an electron injection transport layer.

The reducing dopant concentration in the electron injection transport layer as described above is not particularly limited, but is preferably about 0.1 to 99% by weight.

In addition, you may comprise the organic layer of the organic electroluminescent element which concerns on this invention using a bipolar material. A bipolar material is a material which can transport both a hole and an electron, and can emit light itself.

The material used for a bipolar transport layer and a bipolar light emitting layer is not specifically limited.

 For example, styryl compounds such as (17), (18) and (19), and derivatives thereof, polyterpenes such as paraterphenyl, quaterphenyl, m-phenylene (22) and (23) Aromatic compounds and derivatives thereof, condensed polycyclic aromatic hydrocarbon compounds such as anthracene, triphenylene, perylene, naphthalene (Formula 20), (pyrene), pyrene, coronene, chrysene, naphthacene, tetracene, phenanthrene, Condensed heterocyclic compounds such as carbazole derivatives such as bis (N-arylcarbazole), bis (N-alkenylcarbazole) and bis (N-alkylcarbazole) (Formula 16) and thiophene; Can be mentioned.

Moreover, as a specific example other than these derivatives etc., 4, 4-bis (2, 2- diphenyl-ethen- 1-yl) diphenyl (DPVBi) (Formula 25), spiro6 (Formula 26), 2, 2 ' , 7,7'-tetrakis (carbazol-9-yl) -9,9'-spiro-bifluorene (Formula 27), 4,4'-di (N-carbazolyl) -2 ', 3 ', 5', 6'-tetraphenyl-p-terphenyl (Formula 28), 1,3-bis (carbazol) -9-yl) -benzene (Formula 29), 3-tert-butyl-9,10 -Di (naphtha-2-yl) anthracene (common name: TBADN) (Formula 30) is mentioned.

[Formula 25]

[Formula 26]

[Formula 27]

[Formula 28]

[Formula 29]

[Formula 30]

As a bipolar material, what disperse | distributed the said organic compound in a polymer, an oligomer, or a dendrimer, and what polymerized, oligomerized, or dendrimerized can also be used.

In addition, so-called π conjugated polymers such as polyparaphenylene vinylene, polyfluorene and derivatives thereof, and non-conjugated polymers represented by polyvinylcarbazole can also be used. Moreover, what is called a conjugated oligomer, such as a fluorene oligomer and its derivative (s), etc. can also be used.

Further, copolymers such as poly (vinyltriarylaminevinyloxadiazole) and dendrimers present in the same molecule of a monomer having a hole transporting function and an electron transporting function can also be used.

In addition, the hole injection layer or the electron injection layer may be formed using the above-described bipolar material by applying the oxidative dopant or the reducing dopant as described above. The oxidative dopant is particularly preferably molybdenum oxide and vanadium oxide.

The organic EL material represented by the general formula (1) can be used alone for the light emitting layer, but is dispersed, doped with other hole transport materials, light emitting materials, electron transport materials, etc., or the organic layer in any one of the above. It can also be used in combination with.

In the organic electroluminescent element which concerns on this invention, it is especially preferable to use the said blue light emitting material as a guest material, and to form the light emitting layer contained with another host material. In this case, it is preferable that the density | concentration of the organic EL material represented by the said General formula (1) shall be 0.1 to 99 weight%. Moreover, you may use in combination with another 2 or more types of host material.

The host material may be a material capable of emitting an organic EL material represented by the general formula (1), or may be a fluorescent or phosphorescent light emitting material.

For example, styryl such as polycyclic compounds such as paraterphenyl, quaterphenyl, m-phenylene (Formula 22), (Formula 23) and derivatives thereof, (Formula 17), (Formula 18), and (Formula 19) Compounds and derivatives thereof, ketone compounds such as tetraphenylbutadiene derivatives, pyrazoline derivatives, oxadiazole derivatives, coumarin derivatives, and diaryl ketones and derivatives thereof, anthracene, triphenylene, perylene, naphthalene (Formula 20), 21), condensed polycyclic aromatic hydrocarbon compounds such as pyrene, coronene, chrysene, naphthacene, tetracene, phenanthrene and derivatives thereof, bis (N-arylcarbazole) (Formula 16), bis (N-alkenyl Carbazole derivatives such as carbazole) and bis (N-alkylcarbazole).

Further, for example, aluminum quinolinol complex, benzoxazole azo complex, benzothiazole azo complex, azomethine zinc complex, europium complex, terbium complex, iridium complex, platinum complex and the like, such as Al, Zn, Be, Metal chelate complex materials having Ir, Pt, Tb, Eu, and the like and having oxadiazole, thiadiazole, phenylpyridine, quinoline structure as ligands can also be used. Specific examples thereof include metal chelate complexes represented by Ir (ppz) ₃ (Formula 31) and FIrpic (Formula 32) and derivatives thereof.

[Formula 31]

[Formula 32]

As said host material, what disperse | distributed the said organic compound in a polymer, an oligomer, or a dendrimer, and what was polymerized, oligomerized, or dendrimerized can also be used.

In addition, so-called π conjugated polymers such as polyparaphenylene vinylene, polyfluorene or derivatives thereof, and non-conjugated polymers represented by polyvinylcarbazole can also be used. Moreover, what is called a conjugated oligomer, such as a fluorene oligomer and its derivative (s), etc. can also be used.

In addition, the light emitting layer may be comprised by the bipolar material mentioned above. Blue light emission can also be taken out by containing the organic EL material represented by the said General formula (1) individually or as a mixture in the layer formed from the bipolar material.

The bipolar material used for this light emitting layer may itself be a material that emits fluorescent or phosphorescent light.

The organic layers may be formed by a dry method such as vacuum deposition, sputtering, inkjet, casting, dip coating, bar coating, blade coating, roll coating, gravure coating, flex printing, spray coating, or the like. It can be performed by a wet method. Preferably, film formation is performed by vacuum deposition.

In addition, although the film thickness of each said layer is suitably determined according to circumstances, in consideration of the adaptability of each layer, the total layer thickness etc. which are calculated | required, etc., it is usually preferable to exist in the range of 5 nm-5 micrometers.

In an organic EL device having a layer containing the organic EL material represented by the general formula (1) alone or as a mixture, blue light emission with high color purity obtained by the organic EL material represented by the general formula (1); By combining the green and red light emission, white light emission with high color rendering property can be obtained.

Specifically, as a method of obtaining high color rendering white light emission, a method of adding orange light emission from green light emission and yellow as complementary color to blue light emission by an organic EL material represented by the general formula (1) above, or the above general And a method of independently emitting each of the blue, green, and red light emitting materials including the material represented by Formula (1).

The green light emitting material or the red light emitting material may be a fluorescent or phosphorescent light emitting material.

For example, condensation of arylamine compounds such as quinacridone derivatives, squarylium derivatives, porphyrin derivatives, coumarin derivatives, dicyanopyran derivatives, anthracenediamines, and derivatives thereof, perylene, rubrene, tetracene, decacyclene and the like. And polycyclic aromatic hydrocarbon compounds and derivatives thereof, phenoxazone, quinoxaline derivatives, carbazole derivatives and fluorene derivatives.

Further, for example, aluminum quinolinol complex, benzoxazole azo complex, benzothiazole azo complex, azomethine zinc complex, europium complex, terbium complex, iridium complex, platinum complex and the like, such as Al, Zn, Be, A metal chelate complex material having Ir, Pt, Tb, Eu, or the like and having an oxadiazole, thiadiazole, phenylpyridine, quinoline structure as the ligand can also be used. Specifically, the metal chelate complex represented by Ir (ppy) ₃ (Chemical Formula 33) and Irpiq ₃ (Chemical Formula 34) and its derivative (s) are mentioned.

[Formula 33]

[Formula 34]

Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not restrict | limited by the following Example.

Example 1

(Synthesis of TPA)

TPA was synthesize | combined according to the synthesis scheme shown below.

[Formula 35]

First, 35.0 g (154.2 mmol) of 4-bromophthalic anhydride, 175 g (1.11 mol) of bromobenzene, and 51.4 g (385.5 mmol) of aluminum chloride were made to react at 90 degreeC for 6 hours.

Water was added to the reaction solution, acid treated with concentrated hydrochloric acid, extracted with chloroform, and washed twice with water. Chloroform was recovered to give a preparation.

The preparation was dispersed and washed with toluene, filtered and dried.

The obtained purified substance was white powder form, and it analyzed by <^1> H-NMR, and it confirmed that 5-bromo-2- (4-bromo benzoyl) benzoic acid which is a target object was contained. The yield as a mixture was 42.1 g (yield 71.1%).

41.0 g of a mixture containing 5-bromo-2- (4-bromobenzoyl) benzoic acid obtained in the above (106.8 mmol (based on 5-bromo-2- (4-bromobenzoyl) benzoic acid)), 403 g of polyphosphoric acid was made to react at 125 degreeC by nitrogen atmosphere for 12 hours.

Water was added to this reaction solution, and the precipitated crystals were separated by filtration and dried, and then dispersion washing with chloroform was repeated twice.

The obtained crystals were pale yellow-white powder type, and as a result of analysis by MS and ¹ H-NMR, it was confirmed that 2,7-dibromoanthraquinone as the target product was contained. The yield was 5.1 g (yield 13.1%).

5.1 g (10.00 mmol) of 2,7-dibromo anthraquinone obtained above, sulfuric acid, and 1.1 g (41.79 mmol) of Al powder were put in order, and it was made to react at 25 degreeC for 4 hours in nitrogen atmosphere.

Ice was poured into this sulfuric acid solution, and the precipitated crystals were separated by filtration and dried.

The obtained preparation was refine | purified in the silica gel column using the chloroform / n-hexane mixed solvent as a developing solvent.

The obtained purified product was white powdery form, and was identified as target product 3,6-dibromoanthrone as a result of analysis by MS and ¹ H-NMR. The yield was 1.9 g (39.4% yield).

2.0 g (5.681 mmol) of 3,6-dibromoanthrone obtained in the above and tetrahydrofuran were put in order, 9 ml (17.04 mmol) of 2M THF solutions of phenylmagnesium bromide were added at room temperature, It was made to react at room temperature for 4 hours, and then at 40 degreeC for 30 minutes.

20 mL of hydrochloric acid was added to this reaction solution at room temperature, and after reacting for 30 minutes, it extracted with chloroform and washed twice with water. Chloroform was recovered to give a preparation.

This preparation was refine | purified in the silica gel column using the chloroform / n-hexane mixed solvent as a developing solvent.

The obtained purified water, and the white crystals were confirmed by ¹ H-NMR, the results of analysis by MS, the target product, 2,7-dibromo-10-phenylanthracene. The yield was 1.8 g (yield 78.3%).

1.9 g (4.610 mmol) of 2,7-dibromo-10-phenylanthracene obtained in the above, 1.7 g (13.83 mmol) of phenylboric acid, toluene, and ethanol were put in order, and 1.5 g of sodium carbonate in 7 ml of water. (13.83 ㎜ol) the dissolved solution, by the addition of _{Pd (PPh 3) 4 0.37 g} (O.323 ㎜ol), under nitrogen atmosphere, was 24 hours at 73 ℃.

This reaction solution was taken out with toluene and washed once with water. Toluene was recovered and a preparation was obtained.

This preparation was refine | purified in the silica gel column using the chloroform / n-hexane mixed solvent as a developing solvent.

The obtained purified water, pale yellow powder-like and, ¹ H-NMR, the results of analysis by MS, was identified as the target product, TPA. The yield was 1.57 g (yield 84.0%).

In the following, TPA which sublimed and refine | purified at 195 degreeC and 3.5 * 10 <^-4> Pa was used further.

TPA synthesized above was dissolved in chloroform for fluorescence analysis, and fluorescence analysis was performed in a solution having a concentration of 10 ⁻⁵ mol / l.

This fluorescence spectrum is shown in FIG.

Comparative Example 1

About the compound (TBP) shown by said (Formula 3), it carried out similarly to Example 1, and performed fluorescence analysis.

This fluorescence spectrum is shown in FIG.

As a result of the above-described fluorescence analysis, as shown in FIGS. 1 and 2, it was confirmed that TPA exhibited a fluorescence maximum wavelength on the short wavelength side and was useful as a high color purity blue light emitting material as compared to TBP.

Example 2

1,3,5,7-tetra (3-methylphenyl) naphthalene (hereinafter, abbreviated to TMN1357) as the host material, and a light emitting layer doped with TPA is used as the organic EL material. The organic EL element which consists of a laminated constitution as shown in FIG. 3 using the compound (DTVPF) shown by General formula (19) was produced by the following method.

(First electrode)

First, the glass substrate on which the patterned transparent conductive film (ITO) was formed at a thickness of 150 nm was subjected to ultrasonic cleaning with pure water and a surfactant, running water washing with pure water, and ultrasonic waves using a 1: 1 mixed solution of pure water and isopropyl alcohol. The washing process was carried out in the order of washing and boiling treatment with isopropyl alcohol. The substrate was slowly pulled up from boiling isopropyl alcohol, dried in isopropyl alcohol vapor, and finally, ultraviolet ozone washing was performed.

This substrate was used as the anode 1, placed in a vacuum chamber, evacuated to 1 × 10 ⁻⁶ Torr, and formed in each of the molybdenum boats each filled with a vapor deposition material in a predetermined pattern. In order to form the deposition mask for the above, conducting heating of the boat and evaporating the deposition material, film formation of each organic layer was performed in order.

(Hole injection transport layer)

Using the compound (DTVPF) shown in the above formula (19) as the hole transporting material, each boat was simultaneously energized and co-deposited together with molybdenum trioxide (MoO ₃ ). The hole injection layer 2 of DTVPF: MoO ₃ = 67:33 was formed with a film thickness of 10 nm.

Next, the hole transport layer 3 which consists only of DTVPF was formed in the film thickness of 56 nm.

(Light emitting layer)

The light emitting layer 4 of TMN1357: TPA = 98: 2 was formed in 20 nm thick.

(Electron injection transport layer)

An electron transport layer 5 made of DTVPF was formed with a thickness of 15 nm.

On it, an electron injection layer 6 having a DTVPF: Liq = 50:50 was formed with a film thickness of 10 nm as an electron transporting material.

(Second electrode)

The mask was exchanged while the vacuum chamber was kept in vacuum, a mask for cathode deposition was provided, and an aluminum (Al) layer was formed with a thickness of 100 nm to obtain a cathode 7.

The vacuum chamber was returned to atmospheric pressure, the board | substrate which deposited each layer by the above was taken out, it moved to the glove box substituted with nitrogen, and it sealed with the other glass plate using UV hardening resin, and obtained the organic electroluminescent element.

The layer structure of this device is simplified to show ITO (150 nm) / DTVPF: MoO ₃ (10 nm, 67:33) / DTVPF (56 nm) / TMN1357: TPA (20 nm, 98: 2) / DTVPF (15 Nm) / DTVPF: Liq (10 nm, 50:50) / Al (100 nm).

The emission spectrum when a direct current of 1000 A / m 2 is applied to this organic EL element is shown in FIG. 4.

As shown in Fig. 4, pure blue light emission derived from TPA was obtained.

In addition, it was confirmed that the chromaticity of the color of emitted light was (x, y) = (0.165, 0.083) at CIE coordinates (1000 A / m 2), and was blue light with high color purity.

Comparative Example 2

The organic electroluminescent element which has the light emitting layer which doped the compound (TBP) shown by said Formula (3) as a host material as a host material was produced like Example 2, and was produced.

A simplified schematic of the layer structure of this device is shown: ITO (150 nm) / CuPc (20 nm) / NPD (40 nm) / TBADN: TBP (35 nm, 99.15: 0.85) / BAlq (12 nm) / Alq (20 Nm) / LiF / Al (100 nm).

The emission spectrum when a direct current of 1000 A / m 2 is applied to this organic EL element is shown in FIG. 5.

As shown in Fig. 5, light blue light emission derived from TBP was obtained.

In addition, the chromaticity of the emitted color was (x, y) = (0.15, 0.19) in the CIE coordinate (1000 A / m 2), and the color purity was lower than that of the device using TPA.

In the said Example 2 and the comparative example 2, it was confirmed that TPA is a blue light emitting material excellent in color purity compared with TBP.

As mentioned above, the organic electroluminescent material represented by General formula (1) which concerns on this invention is able to obtain blue light emission with high color purity, and it is confirmed that utility is high, and to the light source and display apparatus which require high color purity Application is expected.

1 shows a fluorescence spectrum of TPA.

2 shows the fluorescence spectrum of TBP.

3 is a cross-sectional view schematically showing the layer structure of the organic EL device according to Example 2. FIG.

4 is a graph showing the emission spectrum of the organic EL device according to Example 2. FIG.

5 is a graph showing the emission spectrum of the organic EL device according to Comparative Example 2. FIG.

Claims (4)

An organic electroluminescent material represented by the following general formula (1):

Herein, R ₁ to R ₇ are selected from hydrogen, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, and an aryloxy group, and may be the same or different groups, and A _{1 to} A ₃ are substituted or unsubstituted phenyl groups. And a 5- or 6-membered ring substituted or unsubstituted heterocyclic group, and may be the same or different groups. In an organic electroluminescent device having one layer or a plurality of organic layers including a light emitting layer between a pair of electrodes, at least one layer of the organic layer contains the organic electroluminescent material according to claim 1 alone or as a mixture. The organic electroluminescent element characterized by the above-mentioned. The organic electroluminescent device according to claim 2, wherein at least one layer of the organic layer is a light emitting layer comprising the organic electroluminescent material and host material according to claim 1 as a guest material. The organic electroluminescent device according to claim 2 or 3, wherein the electrode is a transparent conductive thin film formed on a transparent substrate.

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