JP4655638B2 - Anthracene derivative, organic electroluminescent element, and display device - Google Patents

Description

  The present invention relates to an anthracene derivative suitably used as an organic material for an organic electroluminescent element, an organic electroluminescent element using the anthracene derivative, and a display device using the element.

  In recent years, a display device using an organic electroluminescent element (so-called organic EL element) has attracted attention as a flat panel display with low power consumption, high response speed, and no viewing angle dependency.

  In general, an organic electroluminescent element has an organic layer sandwiched between a cathode and an anode, and holes and electrons injected from the anode and the cathode, respectively, recombine in the organic layer. Emits light. As the organic layer, for example, a structure in which a hole transport layer, a light emitting layer containing a light emitting material, and an electron transport layer are laminated in order from the anode side, and further, a light emitting material is included in the electron transport layer so as to have an electron transporting property. A structure having a light emitting layer has been developed.

  By the way, the organic electroluminescent element having the above configuration is a self-luminous element. When a display device is configured using the organic electroluminescent element, it is most important to extend the life of the organic electroluminescent element and to ensure the reliability. It becomes one of the important issues. For this reason, research on organic materials constituting organic electroluminescent elements is being pursued.

  In particular, regarding a light emitting material that controls light emission, various studies have been made on red, green, and blue light emitting materials corresponding to the three primary colors. In addition to the indices specific to compounds such as heat resistance and fluorescence quantum yield, the physical properties required of luminescent materials are required to be materials that can solve element characteristics such as color purity and luminance in devices, as well as luminescence lifetime. .

  In particular, blue light-emitting materials have been vigorously developed from the past. For example, materials such as styryl allene or anthracene derivatives are known. A typical anthracene derivative is 9,10-diphenylanthracene having a phenyl group at the 9,10-position. And the structure which aims at thermal stabilization by increasing molecular weight by introduce | transducing a substituent into the phenyl group in this 9,10- diphenylanthracene is disclosed (refer the following patent document 1).

  Further, 9,10-di (2-naphthyl) anthracene (ADN) in which the 9,10-position is substituted from a phenyl group to a naphthyl group is also known as a good blue light emitting material.

  However, since the anthracene derivative having the above structure has a low current efficiency of 2 cd / A or less when the light emitting layer is formed alone, the current efficiency is improved mainly by using it as a host material of the light emitting layer. This has also been studied (see Non-Patent Document 1).

  On the other hand, a configuration in which an anthracene derivative is used as a guest material for a light-emitting layer has been studied. In particular, N, N′-di (anthracen-1-yl) -N, N′-diphenyl-4,4′-benzidine (K-1) is shown as a blue-colored guest material having an anthracene nucleus. (See Patent Document 2 below). It has been shown that the anthracene derivative (K-1) having such a structure is obtained by bonding an amino group directly to an anthracene nucleus and forming an amine compound, thereby obtaining a more efficient device.

  In addition, the use of an anthracene derivative in which the 9,10-position is substituted with a diarylamino group as a light emitting material is also disclosed (see Patent Document 3 and Non-Patent Document 2 below).

JP-A-11-323323 JP-A-8-199162 JP-A-8-53397 2003 SID Symposium Digest, Baltimore, Maryland, USA, May 21, 2003, p971-973 Chemistry of Materials (USA) 2002, Vol. 14, p. 3598-3963

  However, the anthracene derivative in which the 9th and 10th positions of the anthracene skeleton as described above are substituted with an aryl group or an arylamino group, when the organic electroluminescent device is formed using this as a light emitting material, emits green light or blue light close to green. However, high-purity blue light emission could not be obtained.

  For example, Patent Document 2 states that blue light emission is observed at K-1 shown as an anthracene derivative. However, in general, as a skeleton in which an amino group is directly bonded to an anthracene nucleus, for example, in the simplest diphenylaminoanthracene, the emission wavelength is around 480 nm, and thus K-1 emission is blue rather than blue. Synthetic Metals A (US) 2000, 111-112, p. 25-29.

  As for the color development of anthracene derivatives in which the 9,10-positions are substituted with diarylamino groups shown in Patent Document 3, for example, the emission wavelength in 9,10-bis (diphenylamino) anthracene having the smallest molecular weight is 520 nm. Non-Patent Document 2 also describes that it is completely green.

  As described above, each of the anthracene derivatives presented as the light emitting material has a high possibility as a chromophore, but only the light emission color close to green is obtained. Accordingly, an object of the present invention is to provide an anthracene derivative that can be used as an excellent blue light-emitting material, and to provide an organic electroluminescent element and a display device using the anthracene derivative.

An anthracene derivative of the present invention for achieving such an object is an anthracene derivative suitably used as an organic material constituting an organic electroluminescent device, and is represented by the following general formula (1).

In the general formula (1), A ^{1 to} A ⁸ , X, Y, Ar ^{1 to} Ar ⁴ represent the following groups, respectively.

A ^{1 to} A ⁸ are each independently hydrogen, halogen, hydroxyl group, substituted or unsubstituted carbonyl group having 20 or less carbon atoms, substituted or unsubstituted carbonyl ester group having 20 or less carbon atoms, and having 20 or less carbon atoms. A substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group having 20 or less carbon atoms, a substituted or unsubstituted alkoxyl group having 20 or less carbon atoms, a cyano group, a nitro group, or a substituted or unsubstituted group having 30 or less carbon atoms Represents a silyl group.

  X and Y each independently represent a substituted or unsubstituted arylene group having 30 or less carbon atoms, or a substituted or unsubstituted divalent heterocyclic group having 30 or less carbon atoms.

Ar ^{1 to} Ar ⁴ each independently represents a substituted or unsubstituted aryl group having 30 or less carbon atoms, or a substituted or unsubstituted heterocyclic group having 30 or less carbon atoms. Of these, Ar ¹ and Ar ² , Ar ³ and Ar ⁴ may be linked to each other to form a ring.

  Moreover, this invention is also an organic electroluminescent element using the anthracene derivative shown by General formula (1). This organic electroluminescent element includes an organic layer having at least a light emitting layer between an anode and a cathode, and an anthracene derivative having the above-described structure is used for the organic layer. In particular, this anthracene derivative is preferably used as a material constituting the light emitting layer.

  In the anthracene derivative represented by the general formula (1) as described above, the 9th and 10th positions of the anthracene skeleton are not substituted with an aryl group, an arylamino group, or the like, and other substituents or unsubstituted groups are used. The above-described group is provided at the 1st and 5th positions. As a result, it was confirmed that blue light emission with high color purity peculiar to anthracene can be obtained in an organic electroluminescence device using this anthracene derivative as a light emitting material. In addition, the molecular weight ensures a sufficient amount of heat resistance, ensuring good thermal properties, excellent external force and thermal durability, and stable voltage fluctuation. It has sex.

  In addition, since the anthracene derivative represented by the general formula (1) is also an amine compound, it has excellent charge transportability and good light emission efficiency can be obtained.

  Therefore, the organic electroluminescence device of the present invention in which the organic layer is formed using such an anthracene derivative has excellent durability of the organic layer when driven for a long time. Further, by using this anthracene derivative in the light emitting layer of the organic electroluminescent device, particularly excellent light emission characteristics for blue are exhibited.

  The present invention is also a display device including the organic electroluminescent element having the above structure using an anthracene derivative, and particularly preferably, the organic electroluminescent element having the above structure is a blue light emitting element as a part of a plurality of pixels. It is assumed that it is provided in the pixel.

  In such a display device, as described above, a display device using an organic electroluminescent element having a high color purity and luminance and a low luminance attenuation factor as a blue light emitting element is configured. In combination with a green light emitting element, full color display with high color reproducibility becomes possible.

  As described above, by forming the organic layer of the organic electroluminescent element using the anthracene derivative represented by the general formula (1) of the present invention, the durability of the organic layer is improved, and the emission lifetime in the organic electroluminescent element. In addition, it is possible to improve the light emission efficiency, particularly in the blue light emitting region. As a result, a full-color display with high color reproducibility can be realized by configuring a pixel by combining a green light emitting element, a red light emitting element, and a blue light emitting element together with the organic electroluminescent element.

  Embodiments of the present invention will be described below.

<Anthracene derivative>
A more specific example of the anthracene derivative of the present invention represented by the following general formula (1) will be described.

  The anthracene derivative represented by the general formula (1) is an anthracene derivative that is preferably used in the organic layer of the organic electroluminescence device, and the substituents X and Y are interposed independently at the 1-position and the 5-position of the anthracene skeleton, respectively. It is bound with an amino group.

In the general formula (1), the substituents A ^{1 to} A ^{8 at} positions other than the 1st and 5th positions of the anthracene skeleton are each independently hydrogen, halogen, hydroxyl group, substituted or non-substituted with 20 or less carbon atoms. Substituted carbonyl group, substituted or unsubstituted carbonyl ester group having 20 or less carbon atoms, substituted or unsubstituted alkyl group having 20 or less carbon atoms, substituted or unsubstituted alkenyl group having 20 or less carbon atoms, and having 20 or less carbon atoms It represents a substituted or unsubstituted alkoxyl group, a cyano group, a nitro group, or a substituted or unsubstituted silyl group having 30 or less carbon atoms.

  The carbonyl group includes an aldehyde group, a ketone group, and a carboxyl group. The alkyl group includes a linear alkyl group, a branched alkyl group, and a cyclic alkyl group.

  In the general formula (1), X and Y are each independently a substituted or unsubstituted arylene group having 30 or less carbon atoms, or a substituted or unsubstituted divalent group having 30 or less carbon atoms. Represents a heterocyclic group.

  X and Y are preferably the same as X and Y in consideration of the convenience in synthesizing the anthracene derivative of the general formula (1).

Further, the substituents Ar ^{1 to} Ar ⁴ bonded to nitrogen (N) bonded to X and Y in the general formula (1) are each independently substituted or unsubstituted having 30 or less carbon atoms having a substituent. It represents a substituted aryl group or a substituted or unsubstituted heterocyclic group having 30 or less carbon atoms. Of these, Ar ¹ and Ar ² , Ar ³ and Ar ⁴ may be linked to each other to form a ring.

Such Ar ¹ to Ar ^4, when the general formula anthracene derivative (1) Considering convenience in the case of synthesis, the Ar ¹ and Ar ³ are the same, is the same as Ar ² and Ar ⁴ Preferably there is.

Here, the aryl group constituting Ar ^{1 to} Ar ⁴ is preferably composed of 30 or less carbon atoms, for example, phenyl group, 1-naphthyl group, 2-naphthyl group, fluorenyl group, 1-anthryl group. 2-anthryl group, 9-anthryl group, 1-phenanthryl group, 2-phenanthryl group, 3-phenanthryl group, 4-phenanthryl group, 9-phenanthryl group, 1-naphthacenyl group, 2-naphthacenyl group, 9-naphthacenyl group 1-pyrenyl group, 2-pyrenyl group, 4-pyrenyl group, 1-chrycenyl group, 6-chrycenyl group, 2-fluoranthenyl group, 3-fluoranthenyl group, 2-biphenylyl group, 3-biphenylyl Group, 4-biphenylyl group, o-tolyl group, m-tolyl group, p-tolyl group, pt-butylphenyl group and the like.

  Moreover, the arylene group which comprises the said X and Y in General formula (1) can illustrate the arylene group derived | led-out from the aryl group illustrated above. Among them, the arylene group used as X and Y is preferably one having a phenyl nucleus, a biphenyl nucleus, or a naphthyl nucleus.

The heterocyclic group constituting Ar ^{1 to} Ar ⁴ is preferably one having 30 or less carbon atoms, for example, 1-pyrrolyl group, 2-pyrrolyl group, 3-pyrrolyl group, pyrazinyl group, 2-pyridinyl. Group, 3-pyridinyl group, 4-pyridinyl group, 1-indolyl group, 2-indolyl group, 3-indolyl group, 4-indolyl group, 5-indolyl group, 6-indolyl group, 7-indolyl group, 1-isoindolyl Group, 2-isoindolyl group, 3-isoindolyl group, 4-isoindolyl group, 5-isoindolyl group, 6-isoindolyl group, 7-isoindolyl group, 2-furyl group, 3-furyl group, 2-benzofuranyl group, 3-benzofuranyl group Group, 4-benzofuranyl group, 5-benzofuranyl group, 6-benzofuranyl group, 7-benzofuranyl group, 1-isobenzo Ranyl group, 3-isobenzofuranyl group, 4-isobenzofuranyl group, 5-isobenzofuranyl group, 6-isobenzofuranyl group, 7-isobenzofuranyl group, quinolyl group, 3-quinolyl group 4-quinolyl group, 5-quinolyl group, 6-quinolyl group, 7-quinolyl group, 8-quinolyl group, 1-isoquinolyl group, 3-isoquinolyl group, 4-isoquinolyl group, 5-isoquinolyl group, 6-isoquinolyl group 7-isoquinolyl group, 8-isoquinolyl group, 2-quinoxalinyl group, 5-quinoxalinyl group, 6-quinoxalinyl group, 1-carbazolyl group, 2-carbazolyl group, 3-carbazolyl group, 4-carbazolyl group, 9-carbazolyl group 1-phenanthridinyl group, 2-phenanthridinyl group, 3-phenanthridinyl group, 4-phenanthridinyl group, 6-phenanthridinyl group Nansridinyl group, 7-phenanthridinyl group, 8-phenanthridinyl group, 9-phenanthridinyl group, 10-phenanthridinyl group, 1-acridinyl group, 2-acridinyl group, 3-acridinyl group, 4-acridinyl group, 9-acridinyl group, etc. are mentioned.

  Moreover, the bivalent heterocyclic group which comprises said X and Y in General formula (1) can illustrate the bivalent thing derived | led-out from the heterocyclic group illustrated above.

Among the groups indicated as A ^{1 to} A ⁸ and X, Y, Ar ¹ , Ar ² , Ar ³ and Ar ⁴ described above, the substituent for the group which may further have a substituent is as follows. , Halogen, hydroxyl group, carbonyl group, carbonyl ester group, cyclic alkyl group, alkenyl group, alkoxy group, aryl group, heterocyclic group, cyano group, nitro group, or silyl group.

  Here, the group which may further have a substituent is a carbonyl group, a carbonyl ester group, an alkyl group, an alkenyl group, an alkoxyl group, a silyl group, an arylene group, a divalent heterocyclic group, an aryl group. And a heterocyclic group.

  The carbonyl group includes an aldehyde group, a ketone group, and a carboxyl group. The alkyl group includes a linear alkyl group, a branched alkyl group, and a cyclic alkyl group.

  Tables 1-a to 1-d below show exemplary structures of the general formula (1). The anthracene derivatives of the present invention are limited to the structures illustrated here as long as they are included in the above-mentioned range. is not.

The anthracene derivative of the present invention shown as an example above can be synthesized by various methods, and examples include the following methods a) to c).
a) A synthesis method in which a halogenated anthracene is coupled by a Grignard reaction using magnesium.
b) A method in which a halogenated anthracene is coupled by the Ullmann reaction in the presence of a copper catalyst.
c) A method of synthesizing boronic acid or boronic esterified anthracene and halogenated anthracene by a transition metal catalyst typified by palladium (so-called Suzuki coupling reaction).

  The anthracene derivative of the present invention is used as a material constituting the organic layer of the organic electroluminescent element, and it is preferable to increase the purity before being subjected to the manufacturing process of the organic electroluminescent element. It should be 95% or more, more preferably 99% or more. As a method for obtaining such a high-purity anthracene derivative, in addition to a recrystallization method, a reprecipitation method, or a column purification using silica or alumina, which is a purification after the synthesis of an anthracene derivative, a known method by sublimation purification or zone melt method is used. High purity methods can be used.

  Further, by repeating these purification methods or combining different purification methods, the mixture of unreacted anthracene derivatives, reaction by-products, catalyst residues, or residual solvents in the present invention is reduced, and more It is possible to obtain an organic electroluminescent element having excellent device characteristics.

  Further, this compound is composed of the organic light-emitting material, particularly by suppressing the deterioration reaction from the oxidation and decomposition by taking the following storage methods a) to c) from the external factors such as light and oxygen. In the organic electroluminescence device, not only provides superior light emission characteristics, but also exhibits an effect in reducing the load on the manufacturing apparatus.

a) After synthesizing the organic light emitting material, immediately leave it in a cool place. The storage temperature is preferably in the range of -100 ° C to 100 ° C, more preferably in the temperature range of -50 ° C to 50 ° C.
b) After synthesizing the organic light emitting material, immediately store it in a light-shielding container.
c) After synthesizing the organic light emitting material, the synthesized organic light emitting material is stored in an inert gas atmosphere such as nitrogen, carbon dioxide, argon or the like.

  The anthracene derivative of the present invention, exemplified by the general formula (1) and structural formula as described above, has other substituents without substituting the 9th and 10th positions of the anthracene skeleton with an aryl group or an arylamino group. Or it is set as the structure which was made into unsubstituted and provided the group mentioned above in the 1st, 5th position of the anthracene skeleton.

  Thereby, in the organic electroluminescent element using this anthracene derivative as a light emitting material, blue light emission with high color purity peculiar to anthracene can be obtained. In addition, the molecular weight ensures a sufficient amount of heat resistance, ensuring good thermal properties, excellent external force and thermal durability, and stable voltage fluctuation. It has sex.

  The anthracene derivative having the above structure is also an amine compound in which an anthracene skeleton is bonded to an anthracene group via an arylene group or a divalent heterocyclic group, so that it has excellent charge transportability and good light emission efficiency. can get.

  Therefore, the organic electroluminescence device of the present invention in which the organic layer is formed using such an anthracene derivative has excellent durability of the organic layer when driven for a long time. In addition, it also exhibits excellent light emission characteristics particularly in blue.

  Furthermore, the anthracene derivative according to the present invention has both electron transport performance and hole transport performance. For this reason, as will be described in detail below, among the organic layers of the organic electroluminescent device, it can be used as a light emitting layer also serving as an electron transporting layer or as a light emitting layer also serving as a hole transporting layer. . It is also possible to adopt a structure in which the anthracene derivative according to the present invention is sandwiched between the electron transport layer and the hole transport layer as a light emitting layer.

<Organic electroluminescent element and display device using the same>
Next, the structure of the organic electroluminescent element (organic EL element) using the organic luminescent material described above will be described in detail with reference to FIG.

  An organic electroluminescent element 11 shown in FIG. 1 is configured as a top emission type element in which an anode 13, an organic layer 14, and a cathode 15 are laminated in this order on a substrate 12, and light is extracted from the side opposite to the substrate 12. ing.

  Here, the substrate 12 is a support on which the organic electroluminescence elements 11 are arranged and formed on one main surface side thereof, and may be a well-known one, for example, made of quartz, glass, metal foil, or resin. Of these, quartz and glass are preferable. In the case of resin, methacrylic resins represented by polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polyethylene naphthalate (PEN) are used. ), Polyesters such as polybutylene naphthalate (PBN), polycarbonate resin, and the like, but it is necessary to perform a laminated structure and surface treatment that suppress water permeability and gas permeability.

The anode 13 provided on the substrate 12 has a high work function from the vacuum level of the electrode material in order to inject holes efficiently, for example, chromium (Cr), molybdenum (Mo), tungsten (W). , Copper (Cu), silver (Ag), gold (Au), alloy of tin oxide (SnO ₂ ) and antimony (Sb), ITO (indium tin oxide), InZnO (indium zinc oxide), zinc oxide (ZnO) An alloy of aluminum and aluminum (Al), and oxides of these metals and alloys are used alone or in a mixed state. The anode 13 can be produced by, for example, a sputtering method.

  When the driving method of the display device configured using the organic electroluminescent element 11 is an active matrix method, the anode 13 is patterned for each pixel and connected to a driving thin film transistor provided on the substrate 12. It is provided in the state that was done. Further, although not shown here, an insulating film is provided on the anode 13, and the surface of the anode 13 of each pixel is exposed from the opening of the insulating film. And

  And the organic layer 14 provided on this anode 13 turns into a layer comprised using the organic luminescent material peculiar to this invention. The organic layer 14 is formed, for example, by laminating four layers of a hole injection layer 14a, a hole transport layer 14b, a light emitting layer 14c, and an electron transport layer 14d in this order from the anode 13 side. In addition to using a compound that emits fluorescence or phosphorescence when an electric field is applied to each of these layers 14a to 14d, a compound having an electron or hole transport ability is appropriately used. To do.

  And in the organic electroluminescent element 11 of this invention, at least one layer of the positive hole transport layer 14b, the light emitting layer 14c, and the electron carrying layer 14d is comprised using the anthracene derivative shown using the said General formula (1). It has been done. In particular, the light-emitting layer 14c is preferably configured using the above-described anthracene derivative. For this reason, below, the case where the anthracene derivative mentioned above is used for the light emitting layer 14c is illustrated.

  Here, the hole injection layer 14a and the hole transport layer 14b are for increasing the efficiency of hole injection into the light emitting layer 14c, respectively. Examples of the material for the hole injection layer 14a or the hole transport layer 14b include benzine, styrylamine, triphenylamine, porphyrin, triazole, imidazole, oxadiazole, polyarylalkane, phenylenediamine, and arylamine. , Oxazole, anthracene, fluorenone, hydrazone, stilbene, or derivatives thereof, or heterocyclic conjugated monomers, oligomers or polymers such as polysilane compounds, vinylcarbazole compounds, thiophene compounds or aniline compounds Can do.

  As more specific materials for the hole injection layer 14a or the hole transport layer 14b, α-naphthylphenylphenylenediamine, porphyrin, metal tetraphenylporphyrin, metal naphthalocyanine, 4, 4, 4-tris ( 3-methylphenylphenylamino) triphenylamine, N, N, N ′, N′-tetrakis (p-tolyl) p-phenylenediamine, N, N, N ′, N′-tetraphenyl-4,4′- Examples include, but are not limited to, diaminobiphenyl, N-phenylcarbazole, 4-di-p-tolylaminostilbene, poly (paraphenylenevinylene), poly (thiophenevinylene), poly (2,2′-thienylpyrrole), and the like. Is not to be done.

  The light emitting layer 14c is a region in which holes and electrons are injected from each of the anode 13 and the cathode 15 when a voltage is applied by the anode 13 and the cathode 15, and these are recombined. In addition, organic light-emitting materials such as low-molecular fluorescent dyes, fluorescent polymers, and metal complexes are used. In the present embodiment, the light-emitting layer 14c contains anthracene derivatives represented by the general formula (1) and the structural formulas (1) -1 to (1) -34.

  More preferably, the anthracene derivative of the present invention is added as a guest material in the light emitting layer 14c. In this case, the addition amount of the anthracene derivative in the light emitting layer 14c is 1% by volume to 99% by volume, preferably 1% by volume to 50% by volume, and more preferably 20% by volume or less.

  The host material when an anthracene derivative is used as a guest material is an aromatic hydrocarbon compound composed of a phenylene nucleus, a naphthalene nucleus, an anthracene nucleus, a pyrene nucleus, a naphthacene nucleus, a chrysene nucleus, or a perylene nucleus. Specifically, 9,10-diphenylanthracene, 9,10-di (1-naphthyl) anthracene, 9,10-di (2-naphthyl) anthracene, 1,6-diphenylpyrene, 1,6-di (1-naphthyl) ) Pyrene, 1,6-di (2-naphthyl), 1,8-diphenylpyrene, 1,8-di (1-naphthyl) pyrene, 1,8-di (2-naphthyl) pyrene, rubrene, 6,12 -Diphenylchrysene, 6,12-di (1-naphthyl) chrysene, 6,12-di (2-naphthyl) chrysene and the like can be suitably used.

  A small amount of other guest material may be added to the light emitting layer 14c for the purpose of controlling the emission spectrum of the light emitting layer 14c. As such other guest materials, organic substances such as naphthalene derivatives, anthracene derivatives, pyrene derivatives, naphthacene derivatives, berylene derivatives, coumarin derivatives, and pyran dyes are used, and among these aromatic tertiary amine compounds. Are preferably used.

  In the above description, the case where the light emitting layer 14c is configured using the anthracene derivative of the present invention as a guest material has been described. However, in the case where the light emitting layer 14c is formed using the anthracene derivative of the present invention, the light emitting layer 14c made of a simple substance of the anthracene derivative of the present invention may be formed. Moreover, you may use the anthracene derivative of this invention as a host material. In this case, the guest material is configured using a material having high luminous efficiency, for example, an organic light emitting material such as a low molecular fluorescent dye, a fluorescent polymer, or a metal complex. Specific examples of the material used for the light emitting layer 14c include anthracene, naphthalene, indene, phenanthrene, pyrene, naphthacene, triphenylene, anthracene, perylene, picene, fluoranthene, acephenanthrylene, pentaphen, pentacene, coronene, and butadiene. , Coumarin, acridine, stilbene, or derivatives thereof, tris (8-quinolinolato) aluminum complex, bis (benzoquinolinolato) beryllium complex, tri (dibenzoylmethyl) phenanthroline europium complex ditoluyl vinylbiphenyl can be used.

  And the electron carrying layer 14d provided on the light emitting layer 14c comprised as mentioned above is for transporting the electron inject | poured from the cathode 15 to the light emitting layer 14c. Examples of the material for the electron transport layer 14d include quinoline, perylene, bisstyryl, pyrazine, triazole, oxazole, oxadiazole, fluorenone, and derivatives thereof. Specific examples include tris (8-hydroxyquinoline) aluminum (abbreviated as Alq3), anthracene, naphthalene, phenanthrene, pyrene, anthracene, perylene, butadiene, coumarin, acridine, stilbene, or derivatives thereof.

  As mentioned above, each said layers 14a-14d which comprise the organic layer 14 can be formed by methods, such as a vacuum evaporation method and a spin coat method, for example. However, in particular, when a small amount of a guest material is added to the light emitting layer 14c in addition to the anthracene derivative of the present invention for the purpose of controlling the emission spectrum of the light emitting layer 14c, the formation of the light emitting layer 14c Co-evaporation of guest materials.

  The organic layer 14 is not limited to such a layer structure, and has at least the light emitting layer 14c and the hole transport layer 14a or the hole injection layer 14b between the anode 13 and the light emitting layer 14c. If it is a structure, the laminated structure as needed can be selected.

  The light emitting layer 14c may be provided in the organic electroluminescent element 11 as a hole transporting light emitting layer, an electron transporting light emitting layer, or a charge transporting light emitting layer. Furthermore, each layer constituting the organic layer 14, for example, the hole injection layer 14a, the hole transport layer 14b, the light emitting layer 14c, and the electron transport layer 14d may have a laminated structure including a plurality of layers.

  Next, the cathode 15 provided on the organic layer 14 having such a configuration has, for example, a two-layer structure in which a first layer 15a and a second layer 15b are stacked in this order from the organic layer 14 side.

The first layer 15a is made of a material having a small work function and good light transmittance. Examples of such a material include lithium oxide (Li ₂ O) which is an oxide of lithium (Li), cesium oxide (Cs ₂ O) which is an oxide of cesium (Cs), and further, these oxides. Mixtures can be used. Further, the first layer 15a is not limited to such a material. For example, alkaline earth metals such as calcium (Ca) and barium (Ba), alkali metals such as lithium and cesium, and indium ( In), magnesium (Mg), or other low work function metals, or oxides of these metals may be used alone or as a mixture or alloy of these metals and oxides with increased stability. .

  The second layer 15b is constituted by a thin film using a light-transmitting layer such as MgAg. The second layer 15b may be a mixed layer containing an organic light emitting material such as an aluminum quinoline complex, a styrylamine derivative, or a phthalocyanine derivative. In this case, a layer having optical transparency such as MgAg may be additionally provided as the third layer.

  Each layer constituting the cathode 15 can be formed by a technique such as vacuum deposition, sputtering, or plasma CVD. Further, when the driving method of the display device configured using the organic electroluminescent element 11 is an active matrix method, the cathode 15 is formed by an organic layer 14 and the above-described insulating film, which is not shown here, by an anode. 13 is formed in a solid film shape on the substrate 12 in an insulated state and used as a common electrode of each pixel.

  Needless to say, the cathode 15 is not limited to the laminated structure as described above, and an optimum combination and laminated structure may be adopted according to the structure of the device to be manufactured. For example, the configuration of the cathode 15 of the above embodiment includes an inorganic layer (first layer 15a) that promotes functional separation of each electrode layer, that is, electron injection into the organic layer 14, and an inorganic layer (second layer 15b) that controls the electrode. Is a laminated structure in which and are separated. However, the inorganic layer that promotes electron injection into the organic layer 14 may also serve as the inorganic layer that controls the electrode, and these layers may be configured as a single layer structure. Moreover, it is good also as a laminated structure which formed transparent electrodes, such as ITO, on this single layer structure.

  The current applied to the organic electroluminescent element 11 having the above-described configuration is usually a direct current, but a pulse current or an alternating current may be used. The current value and the voltage value are not particularly limited as long as the element is not destroyed. However, considering the power consumption and life of the organic electroluminescent element, it is desirable to emit light efficiently with as little electrical energy as possible.

  Moreover, in the organic electroluminescent light emitting element 11 shown in FIG. 1, the structure which takes out light from upper and lower sides by using the transparent electrode which consists of ITO etc. for the anode 13 may be sufficient.

  When the organic electroluminescent element 11 has a cavity structure, the total film thickness of the organic layer 14 and the electrode layer (cathode 15 in the present embodiment) made of a transparent material or a semi-transparent material is light emission. It is defined by the wavelength and will be set to a value derived from multiple interference calculations. In a so-called TAC (Top Emitting Adoptive Current drive) structure in which a top emission type organic electroluminescence device is provided on a substrate on which a TFT is formed, light is extracted to the outside by actively using this cavity structure. It is possible to improve efficiency and control the emission spectrum.

  Furthermore, although illustration is omitted here, in the display device 1 including the organic electroluminescent element 11 having such a configuration, the organic electroluminescent element 11 is prevented from being deteriorated by moisture, oxygen, or the like in the atmosphere. It is preferable to perform a treatment such as forming a sealing film.

  Although not shown here, in a display device including the organic electroluminescent element 11 having such a configuration, the organic electroluminescent element 11 is a blue light emitting element, and a red light emitting element and a green light emitting element are used together with the blue light emitting element. May be provided in each pixel, and one pixel is formed by using these pixels as sub-pixels, and a plurality of pixels each having one set of these pixels are arranged on the substrate 2 to perform full color display.

  According to the organic electroluminescent element 11 having the configuration described above, the light emitting layer 14c of the organic layer 14 is configured using the anthracene derivative described using the general formula (1). Thereby, the durability and stability of the organic layer 14 can be improved, and electroluminescence based on the high fluorescence characteristic of anthracene can be obtained. As a result, it is possible to improve the light emission lifetime in the organic electroluminescent element 11, and it is possible to improve the color purity particularly in blue light emission.

  A full color display with high color reproducibility can be realized by configuring a pixel by combining a red light emitting element and a green light emitting element together with the organic electroluminescent element of the present invention.

  In the above embodiment, the anthracene derivative of the present invention is used as a constituent material of the light emitting layer 14c (including an electron transporting light emitting layer, a hole transporting light emitting layer, and a charge transporting light emitting layer). Only explained that. However, the anthracene derivative of the present invention is excellent in durability as described in the embodiment of the anthracene derivative, and since it is an amine compound, it has an electron transport property and a hole transport property. The anthracene derivative of the present invention can also be used as a material constituting a layer other than the light emitting layer 14c, such as the electron transport layer 14d, the hole transport layer 14b, and the hole injection layer 14a. It becomes possible to improve durability.

  Further, the organic electroluminescent device of the present invention is not limited to the top emission type, and is not limited to the application to the TAC structure using the same, and the organic layer having at least a light emitting layer is sandwiched between the anode and the cathode. The present invention can be widely applied to the configuration. Therefore, in order from the substrate side, the cathode, the organic layer, and the anode are laminated in sequence, and the electrode located on the substrate side (lower electrode as the cathode or anode) is made of a transparent material and located on the opposite side of the substrate It is also applicable to a so-called transmissive organic electroluminescence device in which the electrode (upper electrode as a cathode or anode) is made of a reflective material so that light is extracted only from the lower electrode side. Even if it is such a structure, it is possible to acquire the same effect by using the organic luminescent material demonstrated using General formula (1) for an organic layer.

  Furthermore, the organic electroluminescent element of the present invention may be an element formed by a pair of electrodes (anode and cathode) and an organic layer sandwiched between the electrodes. For this reason, it is not limited to what comprised only a pair of electrode and organic layer, and other components (for example, an inorganic compound layer and an inorganic component) coexist in the range which does not impair the effect of this invention. Is not to be excluded.

  A synthesis example of the anthracene derivative of the present invention and an example of the organic electroluminescence device of the present invention using this anthracene derivative will be specifically described. Here, first, Synthesis Examples 1 to 3 of the organic light-emitting material of the present invention will be described, and then Examples 1 to 3 of the production procedure of the organic electroluminescent element using these organic light-emitting materials and the organic electric field of the comparative example. A procedure for manufacturing a light-emitting element and the evaluation results thereof will be described.

<Synthesis example 1 of anthracene derivative>
The anthracene derivative shown by Structural Formula (1) -1 in Table 1-a was obtained by repeating the Suzuki coupling reaction shown in the following Reaction Formulas 1-2.

First, referring to the above reaction formula 1, after a 1000 ml three-necked flask equipped with a mechanical stirrer was sufficiently replaced with nitrogen, 500 ml of DMSO was added as a solvent, followed by 4-bromotriphenylamine (32 g, 100 mmol). , Bispinacolate diboron (30 g, 120 mmol), potassium acetate (CH ₃ COOK) (20 g, 200 mmol), and tetrakis (triphenylphosphine) palladium [Pd (PPh ₃ ) ₄ ] (1.16 g, 1 mmol) Added to solvent. While stirring, the temperature was raised to 90 ° C. and reacted for 6 hours after reaching a steady state.

  After completion of the reaction, the solvent DMSO was removed by distillation under vacuum conditions, and then redissolved with toluene and washed with water. Subsequently, the toluene layer side was dried with sodium sulfate and then concentrated, and passed through a silica column with a mixed solvent of hexane: toluene to obtain compound (C1) in a yield of 83%.

Subsequently, referring to the above reaction formula 2, after a 500 ml three-necked flask equipped with a mechanical stirrer was sufficiently substituted with nitrogen, 1,5-dibromoanthracene (6.7 g, 20 mmol), the compound synthesized above ( C1) (15.5 g, 42 mmol) was added sequentially and 50 ml of toluene was poured. While stirring, 50 ml of a 2.0 mol / liter Na ₂ CO ₃ aqueous solution was added, and the mixed solution was bubbled with nitrogen for 10 minutes to sufficiently exhaust dissolved oxygen in the solution. Subsequently, tetrakis (triphenylphosphine) palladium [Pd (PPh ₃ ) ₄ ] (232 mg, 200 μmol) was added as a palladium catalyst component, and then the temperature was raised and reacted at the reflux temperature (90 °) for 10 hours.

After completion of the reaction, the reaction mixture was cooled to room temperature, and the precipitated solid was sufficiently washed with acetone and ethanol to obtain 9.9 g (yield 75%) of a yellow solid. As a result of measuring the obtained solid by ¹ H-NMR, ¹³ C-NMR, and FD-MS, it was confirmed that it was the target anthracene derivative [Structural Formula (1) -1 in Table 1-a]. did.

<Synthesis example 2 of anthracene derivative>
The anthracene compound shown by Structural Formula (1) -17 in Table 1-b was obtained through the Suzuki coupling reaction shown in the following Reaction Formula 3.

  First, referring to the above reaction formula 3, by using 4,4′-dibromotriphenylamine and phenylboronic acid as starting materials and performing Suzuki coupling according to the above reaction formula 2, structural formula (1) — Compound (C2) [N- (4 bromophenyl) -N-phenylbiphenyl-4-amine] corresponding to the side of 17 was obtained.

  Subsequently, the same procedure as in Reaction Scheme 1 of Synthesis Example 1 was performed using Compound (C2) obtained in Reaction Scheme 3 instead of 4-bromotriphenylamine in Reaction Scheme 1 of Synthesis Example 1, and the compound ( An anthracene derivative of the structural formula (1) -17 in Table 1-b was obtained by converting C2) into a boronic ester and further performing a coupling reaction according to Reaction Formula 2.

<Synthesis example 3 of anthracene derivative>
The anthracene compound represented by Structural Formula (1) -19 in Table 1-b was obtained through a coupling reaction represented by the following Reaction Formula 4.

  First, referring to Reaction Formula 4, a 500 ml three-necked flask equipped with a mechanical stirrer was sufficiently replaced with nitrogen, and then 4-iodobromobenzene (5.6 g, 20 mmol), N- (1-naphthyl) phenylamine (4.4 g, 20 mmol), sodium-tert-butoxide (1.9 g, 20 mmol) was dissolved in 100 ml of toluene.

  The mixed solution was bubbled with nitrogen for 10 minutes to sufficiently exhaust the dissolved oxygen in the solution. Subsequently, palladium acetate (100 mg, 480 μmol) was added all at once as a palladium catalyst component, and tri (t-butylphosphine) (380 mg, 1.8 mmol) dissolved in 20 ml of toluene was added dropwise with stirring. After completion, the temperature was raised and the reaction was carried out at the reflux temperature for 3 hours.

  After completion of the reaction, the reaction mixture was cooled to room temperature, the organic layer was washed 5 times with water, and the organic layer was dried over magnesium sulfate. The solution was concentrated and then passed through a silica column with a mixed solvent of hexane / toluene to obtain an intermediate compound (C3) [N- (4 bromophenyl) -N-phenylnaphthalen-1-amine] in a yield of 72. %. This compound (C3) corresponds to the side part of the structural formula (1) -19.

  Subsequently, in place of 4-bromotriphenylamine used in Reaction Scheme 1 shown in Synthesis Example 1 except that compound (C3) obtained in Reaction Formula 4 was used, In the same manner, the compound (C3) was converted to a boronic ester. Then, the anthracene derivative shown to Structural formula (1) -19 of Table 1-b was obtained by performing the coupling reaction according to Reaction formula 2 shown in the synthesis example 1. FIG.

<Example 1>
Using the anthracene obtained in Synthesis Example 1 [Structural Formula (1) -1 in Table 1-a], a top emission organic electroluminescent element (see FIG. 1) was produced as follows.

First, a film (thickness: about 100 nm) made of chromium (Cr) is formed as an anode 13 on a substrate 12 made of a glass plate of 30 mm × 30 mm, and silicon dioxide (SiO ₂ ) not shown here is further removed. A cell for an organic electroluminescent element was produced by depositing the light emitting region other than 2 mm × 2 mm with an insulating film by vapor deposition.

Next, a film made of the following m-MTDATA was formed as a hole injection layer 14a of the organic layer 14 with a film thickness of 30 nm (deposition rate: 0.2 to 0.4 nm / sec) by a vacuum evaporation method. However, m-MTDATA is 4,4 ′, 4 ″ -tris (phenyl-m-tolylamino) triphenylamine.

Next, as the hole transport layer 14b, a film made of the following α-NPD was formed with a film thickness of 30 nm (deposition rate: 0.2 to 0.4 nm / sec). However, α-NPD is N, N′-bis (1-naphthyl) -N, N′-diphenyl [1,1′-biphenyl] -4,4′-diamine.

On the hole injection layer 14a and the hole transport layer 14b thus formed, the following ADN and the anthracene derivative synthesized in Synthesis Example 1 [Structural Formula (1) -1] are formed as the organic light emitting layer 14c. Vapor deposition was performed with a film thickness of 50 nm. However, ADN is 9,10-di (2-naphthyl) anthracene (ADN) and was used as a host material. Then, 4% by volume of the anthracene derivative [Structural Formula (1) -1] as a guest material was doped into this ADN at a relative film thickness ratio to obtain a light emitting layer 14c.

Next, the following Alq3 was deposited to a thickness of 20 nm as the electron transport layer 14d. Alq3 is 8-hydroxyquinoline aluminum.

As described above, after forming the organic layer 14 formed by sequentially laminating the hole injection layer 14a, the hole transport layer 14b, the light emitting layer 14c, and the electron transport layer 14d, as the first layer 15a of the cathode 15, A film made of Li ₂ O was formed with a film thickness of about 0.3 nm (deposition rate: 0.01 nm / sec.) By vacuum evaporation. Finally, a 10 nm-thick MgAg film was formed as the second layer 15b of the cathode 15 on the first layer 15a by vacuum deposition.

When the organic electroluminescence device produced in this way was driven by a direct current voltage, a blue color was confirmed, and the emission luminance was 680 cd / m ² at a voltage of 4.5V. In addition, the external quantum yield at this luminance was 4.5%, and the color purity was (0.13, 0.11).

<Example 2>
Implementation was performed except that the anthracene derivative [Structural Formula (1) -17] synthesized in Synthesis Example 2 was used instead of the anthracene derivative [Structural Formula (1) -1] as the guest material of the light-emitting layer 14c in FIG. An organic electroluminescent element was produced in the same manner as in Example 1, and the same evaluation was performed.

Table 2 below shows the guest material of the light emitting layer 14c and the evaluation result. The structural formula number of the guest material conforms to Table 1-a and Table 1-b.

<Comparative Examples 1 and 2>
As the guest material of the light emitting layer 14c in FIG. 1, the anthracene derivative (D-1) shown in Non-Patent Document 2 is used in Comparative Example 1, and the anthracene derivative (D--) shown in Patent Document 2 is used in Comparative Example 2. An organic electroluminescent element was produced in the same manner as in Example 1 except that 2) was used, and the same evaluation was performed. In Table 2, the evaluation results are also shown.

<Example 3>
In the following manner, a transmissive organic electroluminescent device for extracting emitted light from the substrate side was produced.

  In a vacuum deposition apparatus, a substrate 12 made of 30 mm × 30 mm glass having an anode 13 made of ITO having a thickness of 100 nm formed on one surface was set.

  As a vapor deposition mask, a metal mask having a plurality of 2.0 mm × 2.0 mm unit openings is arranged close to the anode 13 side of the substrate 12, and as a hole injection layer 14a of the organic layer 14 by vacuum vapor deposition, A film made of m-MTDATA was formed to a thickness of 30 nm. Next, as the hole transport layer 14b, a film made of the α-NPD was formed with a film thickness of 35 nm (deposition rate: 0.2 to 0.4 nm / sec).

On the hole injection layer 14a and the hole transport layer 14b thus formed, the following DTBADN and the anthracene derivative synthesized in Synthesis Example 3 [Structural Formula (1) -19] are formed as the organic light emitting layer 14c. Vapor deposition was performed with a film thickness of 40 nm. However, DTBADN was 2,6-di-tertbutyl-9,10-di (2-naphthyl) anthracene and was used as a host material. This DTBADN was doped with anthracene derivative [Structural Formula (1) -19] as a guest material at a relative film thickness ratio of 2.5% by volume to obtain a light emitting layer 14c.

  Next, the Alq3 was deposited to a thickness of 20 nm as the electron transport layer 14d.

  As described above, after forming the organic layer 14 formed by sequentially laminating the hole injection layer 14a, the hole transport layer 14b, the light emitting layer 14c, and the electron transport layer 14d, as the first layer 15a of the cathode 15, A film made of LiF was formed with a film thickness of about 0.3 nm (deposition rate: 0.01 nm / sec.) By vacuum evaporation. Finally, an MgAg film having a thickness of 70 nm was formed as the second layer 15b of the cathode 15 on the second layer 15a by a vacuum deposition method.

When the organic electroluminescent device produced in this way was driven by a direct current voltage, blue color was confirmed, the emission luminance was 1470 cd / m ² at a voltage of 6.8 V, and the current efficiency was 6.1 cd / A. Moreover, the external quantum efficiency in this light emission luminance was 3.8%, and the color coordinate was (0.14, 0.22).

  The results are also shown in Table 2.

  From the results shown in Table 2 above, in Examples 1 and 2 in which the anthracene derivative of the present invention was used as the guest material of the light emitting layer 14c, anthracene derivatives (D-1) and (D- Compared with Comparative Examples 1 and 2 using 2) as the guest material of the light emitting layer 14c, the color coordinates (particularly the Y value) are excellent, and the color purity is improved.

  Since the known material used in Comparative Examples 1 and 2 emits green light, it is obvious that the emission luminance is higher than that of blue light emission, and the external quantum energy that defines the photon generation rate for electron injection independent of the light emission color. When compared using the rate index, it was confirmed that the external quantum efficiencies of Examples 1 and 2 were maintained high.

  And from the result measured about Example 3, even when the transmissive | pervious type | mold which used ITO as an anode as an organic electroluminescent element was comprised, it is the same by using the anthracene derivative of this invention as a guest material of the light emitting layer 14c. It was confirmed that the effect of was obtained.

  As a result, a full color display with high color reproducibility is obtained by constructing a pixel by combining a green organic electroluminescent element and a red organic electroluminescent element together with the blue organic electroluminescent element using the anthracene derivative of the present invention. Was confirmed to be possible.

It is a cross-sectional block diagram for demonstrating an example of the organic electroluminescent element of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 13 ... Anode, 14 ... Organic layer, 14b ... Hole transport layer, 14c ... Light emitting layer, 14d ... Electron transport layer, 15 ... Cathode

Claims (8)

An anthracene derivative represented by the following formula.

An anthracene derivative represented by the following formula.

An anthracene derivative represented by the following formula.

Sandwiching an organic layer having at least a light emitting layer between the anode and the cathode,
The organic electroluminescent element by which the said organic layer is comprised using the anthracene derivative of any one of Claims 1-3. The organic electroluminescent element according to claim 4, wherein the anthracene derivative is used as a material constituting the light emitting layer. The organic electroluminescent element according to claim 5, wherein the light emitting layer contains the anthracene derivative as a guest material. A plurality of organic electroluminescent elements formed by sandwiching at least a light emitting layer between an anode and a cathode are formed on a substrate,
A display device in which at least one organic electroluminescent element according to any one of claims 4 to 6 is used as the organic electroluminescent element. The display device according to claim 7, wherein the organic electroluminescent element according to any one of claims 4 to 6 is provided as a blue light emitting element in a part of the plurality of pixels.

Images