TW201345877A - Novel triphenylene derivatives and organic electroluminescent devices using said derivatives - Google Patents

Abstract

Triphenylene derivatives of the invention are represented by the following general formula (1), wherein Ar1 and Ar2 are aromatic groups. The compounds have a structure in which an aromatic tertiary amine is introduced into a triphenylene ring. Owing to this structure, the compounds exhibit (A) favorable positive hole injection property, (B) large positive hole mobility, (C) excellent electron blocking power, (D) stability in their thin-film state, and (E) excellent heat resistance. The compounds are useful as positive hole transporting materials for use in the organic EL devices.

Description

Novel triazine derivatives and organic electroluminescent elements using the same

The present invention relates to a novel compound (a triphenylene derivative) of an organic electroluminescence device which is suitable for a self-luminous element which is suitable for various display devices, and an organic electroluminescence device having an organic layer containing the compound.

Since an organic electroluminescence device (hereinafter also referred to as an organic EL device) is a self-luminous device, the liquid crystal device is brighter and more excellent in readability, and can be clearly displayed. Therefore, research and development have been actively conducted.

In 1987, CWTang et al. of Eastman Kodak Company made practical application of organic EL elements using organic materials by developing laminated structural elements that assigned various roles to various materials. These are formed by laminating an electron-transporting phosphor and an aromatic amine compound capable of transporting holes, and injecting charges of both into the layer of the phosphor to emit light, and A high brightness of 1000 cd/m ² or more is obtained with a voltage of 10 V or less.

Up to now, many improvements have been made to the practical use of organic electroluminescent elements. For example, a structure in which various characters are further subdivided and a structure in which an anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode are sequentially disposed on a substrate is known. Such components can achieve high efficiency and durability.

In order to improve the luminous efficiency, attempts have been made to utilize triplet excitons and to explore the use of phosphorescent emitters.

The light-emitting layer can also be produced by doping a phosphor or a phosphorescent light in a charge transporting compound called a host material. The selection of the organic material forming each layer in the organic EL element has a significant influence on various characteristics such as efficiency or durability of the element.

In the organic EL device, charges injected from the two electrodes are recombined in the light-emitting layer to obtain light emission, but how the two charges of the holes and electrons can be transported to the light-emitting layer with good efficiency is important. For example, by increasing the hole injectability and increasing the electron blocking property of electrons injected from the cathode, the probability of recombination of the hole and the electron can be improved, and high can be obtained by closing the excitons generated in the light-emitting layer. Luminous efficiency. Therefore, the role of the hole transporting material is important, and a hole transporting material having high hole injection property, large hole mobility, high electron blocking property, and high durability against electrons is being sought.

Further, regarding the life of the element, the heat resistance or the amorphous property of the material is also important. A material having low heat resistance causes thermal decomposition and deterioration of the material even at a low temperature due to heat generated when the element is driven. A material having a low amorphous property may crystallize the film even in a short period of time, causing deterioration of the element. Therefore, the materials used are required to have high heat resistance and good amorphous properties.

As a hole transporting material used for an organic EL element, N,N'-diphenyl-N,N'-bis(α-naphthyl)benzidine (hereinafter abbreviated as NPD) or various aromatic amines is known. Derivatives (for example, refer to Patent Document 1 and Patent Document 2).

Although NPD has a good hole transporting ability, the glass transition point (Tg) which is an index of heat resistance is low, and it is 96 ° C, and the element characteristics are deteriorated due to crystallization under high temperature conditions. Further, among the aromatic amine derivatives described in Patent Document 1 or Patent Document 2, there is an excellent mobility in which the hole mobility is 10 ^-3 cm ² /Vs or more, but some electrons are insufficient in blocking properties. A light-emitting layer is allowed to pass through, and improvement in luminous efficiency cannot be expected, and further improvement in efficiency is required. Therefore, a material having higher electron blocking property and a more stable film and high heat resistance is required.

In the case of a compound having improved properties such as heat resistance and hole injectability, arylamine compounds A and B having a substituted triazine structure represented by the following formula have been proposed in Patent Documents 3 and 4.

However, the use of these compounds in a hole injection layer or a hole transport layer has improved heat resistance, luminous efficiency, etc., but it cannot be said to be perfect, and low driving voltage or current efficiency is also It is not perfect, and there are problems with amorphousness. Therefore, a compound which can improve the amorphous property, has a lower driving voltage, and has higher luminous efficiency is being sought.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 8-48656

[Patent Document 2] Japanese Patent No. 3194657

Patent Document 3: WO2010/002850

[Patent Document 4] WO2011/081423

In order to achieve the above object, the inventors of the present invention have focused on the aromatic tertiary amine structure having high hole injection, transportability, and heat resistance of the triphenylene ring structure or film stability, and designing various benzene ring structures. The compound was chemically synthesized, and various organic electroluminescence elements were tried using this compound, and the results of evaluation of the characteristics of the elements were evaluated, and it was confirmed that high efficiency and excellent durability were obtained, and the present invention was completed.

According to the present invention, there can be provided a triazine derivative which is represented by the following formula (1):

Wherein p and q each represent 0 or an integer from 1 to 4; s represents 0 or an integer from 1 to 3; and Ar ¹ and Ar ² each represent an aromatic hydrocarbon group or an aromatic heterocyclic group, but Ar ¹ and Ar ² may be bonded to each other by a single bond or a methylene group having an substituent, an oxygen atom or a sulfur atom; R ¹ , R ² and R ³ each represent a halogen atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a carbon atom A cycloalkoxy group, an aromatic hydrocarbon group, an aromatic heterocyclic group or an aryloxy group of 5 to 10 is used.

According to the present invention, there is further provided an organic electroluminescence device comprising an organic layer of a pair of electrodes and at least one layer sandwiched therebetween, at least one layer of the organic layer containing the triazine derivative.

The organic EL device of the present invention has, as the organic layer containing a triazine derivative, and has, for example, a hole transport layer, an electron blocking layer, a hole injection layer or a light-emitting layer.

The triazine derivative of the present invention represented by the above formula (1) is a novel compound and has a structure in which an aromatic tertiary amino group (disubstituted aromatic amine group) is introduced into a benzene ring. With regard to such a structure, it has the following characteristics.

(A) The injection characteristics of the hole are good.

(B) The mobility of the hole is large.

(C) Excellent electronic blocking ability.

(D) The state of the film is stable (indicating excellent amorphousness).

(E) Excellent heat resistance.

Therefore, the triazine derivative of the present invention is useful as a hole transporting substance for use in an organic EL device, and is particularly useful as an organic layer provided in an organic EL device because the film state is stable. Moreover, the characteristics of the organic EL element can be imparted as follows.

(F) High luminous efficiency or power efficiency.

(G) The light emission starting voltage is low.

(H) The practical driving voltage is low.

(I) Long component life (high durability).

For example, an organic EL device which forms a hole injection layer and/or a hole transport layer by using the triphenylene derivative of the present invention has a high moving speed, high electron blocking property, and stability to electrons due to injection of a hole. High, can close the excitons generated in the luminescent layer, further increase the probability of recombination of holes and electrons, and exhibit high luminous efficiency. Moreover, the driving voltage is lowered, and durability can be improved.

Further, an organic EL device having an electron blocking layer formed by using the triphenylene derivative of the present invention has high electron-blocking ability and excellent hole transportability, has high luminous efficiency, and has low driving voltage and current. Improved patience and increased maximum brightness.

Moreover, the triazine derivative of the present invention can be used as a host material of a light-emitting layer because it has excellent hole transportability and a wide band gap as compared with a conventional material, for example, When a fluorescent illuminant or a phosphorescent illuminant called a dopant is used as a light-emitting layer, the driving voltage of the organic EL element can be lowered, and the luminous efficiency can be improved.

As described above, the triazine derivative of the present invention is extremely useful as a constituent material of a hole injection layer, a hole transport layer, an electron blocking layer or a light-emitting layer of an organic EL element, and can improve the luminous efficiency of the organic EL element and Power efficiency, reduced utility drive voltage, and improved durability.

1‧‧‧ glass substrate

2‧‧‧Transparent anode

3‧‧‧ hole injection layer

4‧‧‧ hole transport layer

5‧‧‧Lighting layer

6‧‧‧Electronic transport layer

7‧‧‧Electronic injection layer

8‧‧‧ cathode

Figure 1 shows a ¹ H-NMR chart of the compound of Example 1 (Compound 4).

Figure 2 shows a ¹ H-NMR chart of the compound of Example 2 (Compound 14).

Figure 3 shows a ¹ H-NMR chart of the compound of Example 3 (Compound 33).

Figure 4 shows a ¹ H-NMR chart of the compound of Example 4 (Compound 35).

Figure 5 shows a ¹ H-NMR chart of the compound of Example 5 (Compound 98).

Figure 6 shows a ¹ H-NMR chart of the compound of Example 6 (Compound 99).

Fig. 7 is a view showing an example of a layer structure of an organic EL element.

[Formation of the Invention]

The triazine derivative of the present invention is represented by the following formula (1) and has a structure in which an aromatic tertiary amino group (-NAr ¹ Ar ² ) is bonded to a hydrazine ring.

In the above formula (1), p and q representing the number of the substituents R ¹ and R ² bonded to the benzene ring are each represented by 0 or an integer of 1 to 4.

Further, s representing the number of substituents R ³ bonded to the benzene ring, represents 0 or an integer of 1 to 3.

Further, in the general formula (1), Ar ¹ and Ar ² which are bonded to a nitrogen atom of an aromatic tertiary amino group bonded to a benzene ring, each represents an aromatic hydrocarbon group or an aromatic heterocyclic group. The aromatic hydrocarbon group and the aromatic heterocyclic group may be either a monocyclic structure or a condensed polycyclic structure.

Examples of the aromatic group to be used herein include a phenyl group, a biphenyl group, a triphenylene group, a naphthyl group, an anthracenyl group, a phenanthryl group, an anthryl group, a fluorenyl group, a fluorenyl group, a fluorenyl group, and a propadiene. Hydrazine, triphenyl, pyridyl, furyl, pyranyl, thienyl, quinolyl, isoquinolinyl, benzofuranyl, benzothienyl, decyl, carbazolyl, Benzo Azolyl, benzothiazolyl, quin A phenyl group, a benzimidazolyl group, a pyrazolyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a porphyrin group, and a 9,10-dihydroacridinyl group.

Particularly, in the aromatic heterocyclic group, a nitrogen atom in which a carbon atom in the heterocyclic group is bonded to an amine group is preferable.

Further, among the aromatic heterocyclic groups, a furyl group, a benzofuranyl group, a benzo group Oxygen-containing aromatic heterocyclic group such as azole group, dibenzofuranyl group; sulfur-containing aromatic heterocyclic group such as thienyl group, benzothienyl group, benzothiazolyl group, dibenzothiophenyl group or the like; N-phenyl group The carbazolyl group and the N-phenyl-9,10-dihydroacridinyl group are ideal, and particularly the sulfur-containing aromatic heterocyclic group is most preferable.

In the present invention, the aromatic group (aromatic hydrocarbon group and aromatic heterocyclic group) exemplified above is preferably an aromatic hydrocarbon group, an N-phenylcarbazolyl group or a dibenzofuranyl group, and an aromatic hydrocarbon group is preferred. It is especially ideal.

Further, the above aromatic group may have a substituent. Examples of such a substituent include a halogen atom such as a halogen atom; a cyano group; a nitro group; a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom; and a methyl group, an ethyl group, a n-propyl group, an isopropyl group, and a positive group. a linear or branched alkyl group having 1 to 6 carbon atoms such as butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl or n-hexyl; methoxy, a linear or branched alkoxy group having 1 to 6 carbon atoms such as an ethoxy group or a propoxy group; an alkenyl group such as an allyl group; a benzyl group, a naphthylmethyl group or a phenethyl group; An aryloxy group such as a phenoxy group or a tolyloxy group; an aralkyloxy group such as a benzyloxy group or a phenethyloxy group; a phenyl group, a biphenyl group, a triphenylene group, a naphthyl group, an anthranyl group, and a phenanthrene group; An aromatic hydrocarbon group such as a thiol group, a fluorenyl group, a pyrenyl group, a pyrenyl group, a pyrenyl group, a pyrrolyl group or a quinoline group; Base, isoquinolyl, benzofuranyl, benzothienyl, fluorenyl, carbazolyl, benzo Azolyl, benzothiazolyl, quin An aromatic heterocyclic group such as a phenyl group, a benzimidazolyl group, a pyrazolyl group, a dibenzofuranyl group, a dibenzothienyl group or a porphyrin group; an arylvinyl group such as a styryl group or a naphthylvinyl group; A sulfhydryl group such as an acetamyl group or a benzamidine group. The substituents may further have a substituent such as a trifluoromethyl group, and the substituents bonded to Ar ^{1 or} the substituents bonded to Ar ² may be substituted by a single bond or may be substituted with each other. A methylene group (for example, an unsubstituted methylene group or a substituted methylene group such as a dimethylmethylene group), an oxygen atom or a sulfur atom is bonded to form a ring.

In the present invention, as the substituent of the above aromatic group, a linear or branched alkyl group having 1 to 6 carbon atoms is preferable, and a methyl group or a tertiary butyl group is particularly preferable.

Further, the above Ar ¹ and Ar ² may be a single bond or a methylene group which may have a substituent (for example, an unsubstituted methylene group or a substituted methylene group such as a dimethylmethylene group) or an oxygen atom. Alternatively, the sulfur atoms are bonded to each other to form a ring together with the nitrogen atom of the amine group.

Examples of such a ring include a carbazole ring, an acridine ring, and a phenol thiophene. Ring, brown The ring or the like (see the compounds 64 to 70 to be described later), particularly the acridine ring (see the compounds 65 to 67 described later) is preferred.

Further, these rings may have the same substituents as described above.

In the above formula (1), R ¹ , R ² and R ³ bonded to the triazine ring each represent a halogen atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, and an alkyl group having 1 to 6 carbon atoms. a group, a cycloalkyl group having 5 to 10 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cycloalkoxy group having 5 to 10 carbon atoms, an aromatic hydrocarbon group, An aromatic heterocyclic group or an aryloxy group.

In the above R ¹ to R ³ , the alkyl group having 1 to 6 carbon atoms may be linear or branched, and specific examples thereof include methyl group, ethyl group, n-propyl group and isopropyl group. , n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl and the like.

Further, in R ¹ to R ³ , a cycloalkyl group having 5 to 10 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and a carbon number of 5 to 10 are used. The cycloalkoxy group may be linear or branched, and specifically, the following may be exemplified.

Examples of the cycloalkyl group are a cyclopentyl group, a cyclohexyl group, a 1-adamantyl group, a 2-adamantyl group and the like.

Examples of alkenyl groups: vinyl, allyl, and the like.

Examples of alkoxy groups: methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, tert-butoxy, n-pentyloxy, n-hexyloxy and the like.

Examples of the cycloalkoxy group are a cyclopentyloxy group, a cyclohexyloxy group, a cycloheptyloxy group, a cyclooctyloxy group, a 1-adamantyloxy group, a 2-adamantanyloxy group and the like.

Further, the above-mentioned alkyl group, cycloalkyl group, alkenyl group, alkoxy group and cycloalkoxy group may have a substituent, and as such a substituent, an aromatic hydrocarbon group in the above Ar ¹ and Ar ² may be mentioned. And the aromatic heterocyclic group may have the same substituent.

Further, the aromatic hydrocarbon group or the aromatic heterocyclic group in R ¹ to R ³ is also the same as those exemplified above for Ar ¹ and Ar ² , and may have the same substituent.

Examples of the aryloxy group in R ¹ to R ³ include a phenoxy group, a tolyloxy group, a biphenyloxy group, a triphenyloxy group, a naphthyloxy group, a decyloxy group, a phenanthryloxy group, and a decyloxy group. , decyloxy, decyloxy, decyloxy and the like.

Of course, these aryloxy groups may have a substituent, and examples of such a substituent include the same as those of the aromatic hydrocarbon group and the aromatic heterocyclic group in Ar ¹ and Ar ² .

In the present invention, among the terphenyl derivatives represented by the above formula (1), those represented by the following formula (1a) are particularly:

In the formula, p, q, s, Ar ¹ , Ar ² and R ¹ to R ³ are as defined in the formula (1); that is, an aromatic tertiary amino group (-NAr ¹ Ar ² ) bond. It is desirable to form a bis-benzene derivative of the 2-position (β-position) of the benzene ring.

The above-mentioned triazine derivative is a novel compound, for example, synthesized in the following manner.

First, a ternary benzene which is equivalent to a benzene ring of the benzene derivative of the formula (1) is used, and the benzene ring is at the 2-position (β position) by N-brobroammonium. Bromination of ruthenium and the like by cross-coupling reaction of this bromide with an amine compound corresponding to a tertiary amino group (HNAr ¹ Ar ² ), such as Buchwald reaction (for example, refer to Org. Synth., 10, 423 (2002)), is capable of synthesizing a triazine derivative represented by the formula (1a).

Further, in the step of brominating the 2-position of the benzene, the other positions (for example, the 1-position (α-position)) of the benzene may be brominated by changing the reagent and conditions of the bromination. By utilizing this, by performing the same cross-coupling reaction as described above, it is possible to synthesize a triazine derivative having a different bonding position of an aromatic tertiary amino group.

Further, for example, a compound having a benzene ring structure can be synthesized by bromination using N-bromosuccinimide or the like, and various bromides can be synthesized by performing the bromide with various boric acid or boron. The cross-coupling reaction of an acid ester (for example, refer to J. Org. Chem., 60, 7508 (1995)), Suzuki coupling, etc. (for example, see Synth. Commun., 11, 513 (1981)), capable of performing a cis-triazole derivative. The substituent is further introduced.

Further, the purification of the obtained compound can be carried out by column chromatography, adsorption purification using tannin extract, activated carbon, activated clay, etc., by solvent recrystallization or crystallization, etc., and the identification is carried out by NMR analysis.

Among the triazine derivatives of the present invention represented by the above formula (1), specific examples of the desired ones are shown below.

The above-described triazine derivative of the present invention has a glass transition point (Tg) or a high melting point as compared with a conventionally known hole-transporting material, and can form a film excellent in heat resistance, and is stably maintained in an amorphous state. , can maintain the state of the film stably. Further, the electron blocking ability is strong, and for example, a vapor deposition film having a thickness of 100 nm is formed by using the triphenylene derivative of the present invention, and after measuring the work function, an extremely high value is exhibited.

Therefore, the triazine derivative of the present invention is extremely useful as a material for forming an organic layer of an organic EL element.

<Organic EL element>

An organic EL device having an organic layer formed by using the above-described triazine derivative of the present invention has a layer structure as shown, for example, in FIG.

In other words, a transparent anode 2, a hole injection layer 3, a hole transport layer 4, a light-emitting layer 5, and an electron transport layer 6 are provided on the glass substrate 1 (a transparent resin substrate or the like, which is a transparent substrate). The electron injection layer 7 and the cathode 8 are provided.

Of course, the organic EL device to which the triazine derivative of the present invention is applied is not limited to the above layer structure, and an electron blocking layer may be provided between the hole transport layer 4 and the light emitting layer 5, or may be provided in the light emitting layer 5. A hole blocking layer is provided between the electron transport layer 6 and a simple layer structure in which the electron injection layer 7 or the hole injection layer 3 is omitted. For example, in the above multilayer structure, it may be omitted Several layers. For example, on the substrate 1, a simple layer structure in which the anode 2, the hole transport layer 3, the light-emitting layer 5, the electron transport layer 6, and the cathode 8 are provided can be formed.

That is, the triazine derivative of the present invention is suitably used as an organic layer provided between the anode 2 and the cathode 8 described above (for example, the hole injection layer 3, the hole transport layer 4, and the electron blocking not shown). The layer or the forming material of the light-emitting layer 5) is used.

In the above-described organic EL device, the transparent anode 2 may be formed of a known electrode material, and an electrode material having a large work function such as ITO or gold may be deposited on the substrate 1 (a transparent substrate such as a glass substrate). ) formed on the top.

Further, the hole injection layer 3 provided on the transparent anode 2 may be formed by using a conventionally known material such as the following materials, in addition to the above-described triazine derivative of the present invention. .

a porphyrin compound represented by beryl phthalocyanine; a triphenylamine derivative of a starburst type; an arylamine having a structure of a triphenylamine skeleton bonded by a single bond or a divalent group containing no hetero atom (eg trimer or tetramer of triphenylamine); coated polymer materials such as poly(3,4-ethylenedioxythiophene) (PEDOT), poly(styrene sulfonate) (PSS) Or a heterocyclic compound such as hexacyanoazide mixed with benzene; forming a layer (film) using the above-mentioned material, in addition to the vapor deposition method, by spin coating or ink jet method A known method is carried out. The various layers described below can also be formed by vapor deposition, a rotary coating method, an inkjet method, or the like.

The hole transport layer 4 provided on the above-described hole injection layer 3 can be formed by using the above-described triazine derivative of the present invention, and can also be formed using a well-known hole transport material.

The representative of the well-known hole material as described above is as follows.

A benzidine derivative, for example: N,N'-diphenyl-N,N'-di(m-tolyl)benzidine (hereinafter abbreviated as TPD); N,N'-diphenyl-N,N'-bis(α-naphthyl) Benzidine (hereinafter abbreviated as NPD); N, N, N', N'-tetraphenylbenzidine; amine derivative, for example: 1,1-bis[4-(di-4-tolylamino) Phenyl]cyclohexane (hereinafter abbreviated as TAPC); various triphenylamine 3 polymers and tetramers; carbazole derivatives; and the above-mentioned coated polymer materials used as hole injection layers; The compound of the hole transporting material as described above may be formed separately from the film, or may be formed by mixing two or more kinds of the film, or one or more of the above compounds may be used to form a plurality of layers, and such a layer may be laminated. The multilayer film is used as a hole transport layer.

Further, it may be used as a layer of the hole injection layer 3 and the hole transport layer 4, and such a hole may be injected into the ‧ transport layer by using poly(3,4-ethylenedioxythiophene) (hereinafter referred to as It is formed by coating a polymer material such as PEDOT).

Further, in the hole transport layer 4 (the same applies to the hole injection layer 3), a material which is usually used for the layer may be subjected to P-type doping of bromophenylamine hexachloroguanidine or the like. Further, the hole transport layer 4 (or the hole injection layer 3) may be formed using a polymer compound having a basic skeleton of TPD or the like.

Further, an electron blocking layer (which may be disposed between the light-emitting layer 5 and the hole transport layer 4) (not shown) may be formed using the triazine derivative of the present invention having an electron blocking effect, and a known electron may be used. A barrier compound such as a carbazole derivative or a compound having a triphenylsulfonyl group and having a triarylamine structure is formed. Specific examples of the carbazole derivative and the compound having a triarylamine structure are as follows.

<carbazole derivatives>

4,4',4"-tris(N-carbazolyl)triphenylamine (hereinafter abbreviated as TCTA); 9,9-bis[4-(carbazol-9-yl)phenyl]anthracene; Bis(carbazol-9-yl)benzene (hereinafter abbreviated as mCP); 2,2-bis(4-carbazol-9-ylphenyl)adamantane (hereinafter abbreviated as Ad-Cz);

<Compound with triarylamine structure>

9-[4-(carbazol-9-yl)phenyl]-9-[4-(triphenylindenyl)phenyl]-9H-indole; the electron blocking layer is used alone or in combination of two or more. The triazine compound of the present invention may be formed by a hole transporting material as described above, or a plurality of layers of one or more of the hole transporting materials may be used, and a plurality of layers may be laminated. The film acts as an electron blocking layer.

For the light-emitting layer 5 of the organic EL device, for example, a metal complex of a hydroxyquinoline derivative of Alq ₃ may be used, and various metal complexes such as zinc, ruthenium, and aluminum may be used, and an anthracene derivative or a double may be used. Styrylbenzene derivatives, anthracene derivatives, It is formed by a luminescent material such as an azole derivative or a polyparaphenylene extended ethylene derivative.

Further, the light-emitting layer 5 may be composed of a host material and a dopant material.

As a host material in this case, in addition to the above-mentioned luminescent material, a thiazole derivative, a benzimidazole derivative, a polydialkyl hydrazine derivative or the like can be used, and the above-described triazine derivative of the present invention can also be used. .

As the dopant material, quinophthalone, coumarin, rubrene, hydrazine and derivatives thereof, benzopyran derivatives, rhodamine derivatives, amine groups can be used. Styryl derivatives and the like.

Such a light-emitting layer 5 can also be used as a single-layer structure using one type or two or more types of light-emitting materials, or as a multilayer structure in which a plurality of layers are laminated.

Moreover, the phosphor layer 5 can be formed using a phosphorescent material as a light-emitting material.

As the phosphorescent material, a phosphorescent emitter of a metal complex such as ruthenium or platinum can be used. For example, a green phosphorescent emitter such as Ir(ppy) ₃ , a blue phosphorescent emitter such as FIrpic or FIr6, a red phosphorescent emitter such as Btp ₂ Ir(acac), or the like can be used, and these phosphorescent materials are doped. Inject into the hole. It is used as a host material for transportability or as a host material for electron transport.

Made as a hole injection. As the host material for transportability, the triazine derivative of the present invention or 4,4'-bis(N-carbazolyl)biphenyl (hereinafter abbreviated as CBP) or a carbazole derivative such as TCTA or mCP can be used. Wait.

Further, as a host material for electron transport, p-bis(triphenylsulfonyl)benzene (hereinafter abbreviated as UGH2) or 2,2',2"-(1,3,5-phenylene) may be used. Reference (1-phenyl-1H-benzimidazole) (hereinafter abbreviated as TPBI).

Further, in order to avoid concentration extinction, doping of the host material of the phosphorescent luminescent material is preferably carried out by co-evaporation in a range of 1 to 30% by weight based on the entire light-emitting layer.

A hole blocking layer (not shown in FIG. 7) which can be disposed between the light-emitting layer 5 and the electron-transporting layer 6 can be formed using a compound having a hole blocking function known per se.

As an example of a known compound having a hole blocking action as described above, except for a phenanthroline derivative such as Bathocuproin (hereinafter abbreviated as BCP) or bis(2-methyl-8-hydroxyquinoline)-4 In addition to the metal complex of a hydroxyquinoline derivative such as phenylphenol aluminum (III) (hereinafter abbreviated as BAlq), a triazole derivative or a trisole may be mentioned. derivative, Diazole derivatives and the like.

These materials can also be used for the formation of the electron transport layer 6 described below, and the hole blocking layer and the electron transport layer 6 can also be used in combination.

Such a hole blocking layer may be formed as a single layer or a multilayered laminated structure, and each layer may be formed by using one or two or more of the above-described compounds having a hole blocking effect.

As the electron transport layer 6, a compound which is known to be electron transporting property is used, and for example, a metal complex such as hydroxyquinoline derivative of Alq ₃ or BAlq can be used, and zinc, bismuth, aluminum or the like can also be used. Various metal complexes, triazole derivatives, three derivative, Diazole derivatives, thiadiazole derivatives, carbodiimide derivatives, quinolin It is formed by a morphine derivative, a phenanthroline derivative, a silole derivative or the like.

The electron transport layer 6 may be formed in a single layer or a multilayer structure, and each layer may be formed by using one or two or more kinds of the above electron transporting compounds.

Further, the electron injecting layer 7 may be formed by a known one, for example, an alkali metal salt such as lithium fluoride or cesium fluoride, an alkaline earth metal salt such as magnesium fluoride, or a metal oxide such as alumina.

As the cathode 8 of the organic EL element, an electrode material having a low work function such as aluminum or an alloy having a lower work function such as a magnesium-silver alloy, a magnesium-indium alloy, or an aluminum-magnesium alloy can be used as the electrode material.

An organic EL element which forms at least one organic layer (for example, a hole injection layer 3, a hole transport layer 4, an electron blocking layer or a light-emitting layer 5) using the triphenylene derivative of the present invention, has high luminous efficiency and power efficiency, and is practical The driving voltage is low, the light-emitting starting voltage is also low, and it has extremely excellent durability.

[Examples]

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to the examples below.

<Example 1>

Synthesis of (biphenyl-4-yl)-(9,9-dimethyl-9H-indol-2-yl)-(bitriphenylene-2-yl)amine; (synthesis of compound 4)

12.3 g of (biphenyl-4-yl)-(9,9-dimethyl-9H-indol-2-yl)amine, 11.5 g of 2-bromo-triazine, and 3.92 g of sodium tris-butoxide. 180 ml of toluene was added to a reaction vessel substituted with nitrogen, and nitrogen gas was supplied thereto for 30 minutes while irradiating ultrasonic waves.

Next, add palladium acetate 0.15g ginseng (tertiary butyl) phosphine 0.55g

It was heated and stirred at 80 ° C for 3 hours. After cooling to room temperature, 150 ml of toluene and 100 ml of water were added, and then an organic layer was taken by a liquid separation operation.

The organic layer was dried over anhydrous magnesium sulfate, and then evaporated.

The obtained crude product was dissolved in 400 ml of toluene, and adsorbed and purified by using 20.0 g of tannin extract, followed by concentration under reduced pressure, and then crystallization was carried out using a mixed solvent of toluene/methanol, followed by reflux washing with methanol to obtain (biphenyl). -4-yl)-(9,9-dimethyl-9H-indol-2-yl)-(bitriphenylene-2-yl)amine (Compound 4) pale yellow powder 15.2 g (yield 76) %).

The structure was identified using NMR for the obtained pale yellow powder. ^The results of ¹ H-NMR measurement are shown in Fig. 1 .

The following 33 hydrogen signals were detected by ¹ H-NMR (THF-d ₈ ).

δ(ppm)=8.98(1H) 8.68(4H) 8.50(1H) 8.35(1H) 7.72-7.58(9H) 7.50-7.39(6H) 7.28(5H) 7.19(1H) 1.43(6H)

<Example 2>

Synthesis of bis(9,9-dimethyl-9H-indol-2-yl)-(bitriphenylene-2-yl)amine; (synthesis of compound 14)

12.8 g of bis(9,9-dimethyl-9H-inden-2-yl)amine, 10.8 g of 2-bromotriphenylene, 3.67 g of sodium tributoxide, and 220 ml of toluene were added to replace with nitrogen. The reaction vessel was purged with nitrogen for 30 minutes while irradiating the ultrasonic wave.

Next, palladium acetate was added 0.14 g of ginseng (tertiary butyl) phosphine 0.52 g

It was heated and stirred at 80 ° C for 2 hours. After cooling to room temperature, 100 ml of toluene and 100 ml of water were added, and then an organic layer was taken by a liquid separation operation. The organic layer was dried over anhydrous magnesium sulfate, and then evaporated.

This crude product was dissolved in 300 ml of toluene, and adsorbed and purified using 10.0 g of tannin. After concentrating under reduced pressure, crystallization was carried out by using a mixed solvent of toluene/n-hexane, and crystallization was carried out using a mixed solvent of toluene/methanol, followed by reflux washing with methanol to obtain bis(9,9-dimethyl-9H). 12.0 g (yield 60%) of pale yellow powder of -non-2-yl)-(bitriphenyl-2-yl)amine (Compound 14).

The structure was identified using NMR for the obtained pale yellow powder. ^The results of ¹ H-NMR measurement are shown in Fig. 2 .

The following 37 hydrogen signals were detected by ¹ H-NMR (THF-d ₈ ).

δ(ppm)=8.70(2H) 8.64(2H) 8.53(1H) 8.32(1H) 7.69(4H) 7.59(3H) 7.49-7.45(4H) 7.42(2H) 7.28(2H) 7.24-7.19(4H) 1.42 (12H)

<Example 3>

Synthesis of (biphenyl-4-yl)-(4'-tertiarybutylbiphenyl-4-yl)-(bitriphenylene-2-yl)amine; (synthesis of compound 33)

12.5 g of (biphenyl-4-yl)-(4'-tertiarybutylbiphenyl-4-yl)amine, 11.2 g of 2-bromotriphenylene, 3.82 g of sodium tributoxide, and 200 ml of toluene , It was added to a reaction vessel substituted with nitrogen, and nitrogen gas was supplied while irradiating ultrasonic waves for 30 minutes.

Next, 0.15 g of palladium acetate and 0.54 g of ginseng (tertiary butyl) phosphine were added.

It was heated and stirred at 80 ° C for 2 hours. After cooling to room temperature, 150 ml of toluene and 50 ml of water were added, and then an organic layer was taken by a liquid separation operation. The organic layer was dried over anhydrous magnesium sulfate, and then evaporated.

The obtained crude product was dissolved in 200 ml of toluene, and adsorbed and purified using 20.0 g of tannin. After concentrating under reduced pressure, crystallization was carried out by using a mixed solvent of tetrahydrofuran/n-hexane, and crystallization was carried out using a mixed solvent of tetrahydrofuran/methanol, followed by reflux washing with methanol to obtain (biphenyl-4-yl)-(4) 14.7 g (yield 73%) of pale yellow powder of '-tris-butylbiphenyl-4-yl)-(bitriphenyl-2-yl)amine (Compound 33).

The structure was identified using NMR for the obtained pale yellow powder. ^The results of ¹ H-NMR measurement are shown in Fig. 3 .

The following 37 hydrogen signals were detected by ¹ H-NMR (THF-d ₈ ).

δ(ppm)=8.71(2H) 8.65(2H) 8.49(1H) 8.38(1H) 7.60(11H) 7.52(1H) 7.45(3H) 7.40(2H) 7.29(5H) 1.35(9H)

<Example 4>

Synthesis of (4'-tertiary butylbiphenyl-4-yl)-(9,9-dimethyl-9H-indol-2-yl)-(bitriphenylene-2-yl)amine; 35 synthesis)

13.0 g of (4'-tertiary butylbiphenyl-4-yl)-(9,9-dimethyl-9H-indol-2-yl)amine, 10.5 g of 2-bromotriphenylene, benzene 3.58 g of sodium butoxide and 180 ml of toluene were added to a reaction vessel substituted with nitrogen, and nitrogen gas was supplied thereto for 30 minutes while irradiating ultrasonic waves.

Next, 0.14 g of palladium acetate and 0.50 g of ginseng-tertiary butylphosphine were added.

It was heated and stirred at 80 ° C for 2 hours. After cooling to room temperature, 200 ml of toluene and 100 ml of water were added, and then an organic layer was taken by a liquid separation operation. The organic layer was dried over anhydrous magnesium sulfate, and then concentrated under reduced pressure, and then lyophilized using a solvent mixture of tetrahydrofuran/methanol, recrystallized with toluene, and refluxed with methanol to obtain (4'-tertiary butyl linkage). White powder of phenyl-4-yl)-(9,9-dimethyl-9H-indol-2-yl)-(bitriphenyl-2-yl)amine (Compound 35) 11.3 g (yield 57 %).

The structure was identified using NMR for the obtained white powder. ^The results of ¹ H-NMR measurement are shown in Fig. 4 .

The following 41 hydrogen signals were detected by ¹ H-NMR (THF-d ₈ ).

δ(ppm)=8.67(4H) 8.49(1H) 8.34(1H) 7.70(2H) 7.59(7H) 7.49-7.41(6H) 7.29(3H) 7.24(1H) 7.18(1H) 1.42(6H) 1.34(9H)

<Example 5>

6-(9,9-Dimethyl-9H-indol-2-yl)-3-(bitriphenylene-2-yl)-1,1-dimethyl-1,3-dihydroindole ( Synthesis of dihydroindeno)[2,1-b]carbazole; (synthesis of compound 98)

6-bromo-3-(linked tris-phenyl-2-yl)-1,1-dimethyl-1,3-dihydroindeno[2,1-b]carbazole 18.0 g, 2-(4 , 4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-9,9-dimethyl-9H-indole 10.8 g, 2M potassium carbonate aqueous solution 30 ml, toluene 144 ml of ethanol and 36 ml of ethanol were added to a reaction vessel substituted with nitrogen, and nitrogen gas was supplied thereto for 30 minutes while irradiating the ultrasonic wave.

Next, add ytterbium (triphenylphosphine) palladium 1.06g

It was heated and stirred under reflux for 5.5 hours. After cooling to room temperature, 200 ml of toluene and 100 ml of water were added, and an organic layer was taken by a liquid separation operation. The organic layer was dried over anhydrous magnesium sulfate and then evaporated

The obtained crude product was purified by column chromatography (support: silica gel, solvent: dichloromethane/hexane) to give 6-(9,9-dimethyl-9H-indol-2-yl)- White powder of 3-(3-triphenyl-l-yl)-1,1-dimethyl-1,3-dihydroindeno[2,1-b]carbazole (Compound 98) 14.3g Rate 66%).

The structure was identified using NMR for the obtained white powder. ^The results of ¹ H-NMR measurement are shown in Fig. 5 .

The following 39 hydrogen signals were detected by ¹ H-NMR (THF-d ₈ ).

δ(ppm)=9.29(2H) 9.08-8.97(4H) 8.90(1H) 8.84(1H) 8.20-8.09(3H) 8.05(1H) 7.98-7.76(9H) 7.69-7.61(2H) 7.55-7.40(4H ) 1.74(6H) 1.65(6H)

<Example 6>

3,7-bis(dibenzofuran-4-yl)-10-(linked tris-2-phenyl)-10H-morphine Synthesis; (synthesis of compound 99)

3,7-dibromo-10-(bitriphenyl-2-yl)-10H-morphine 8.9 g, 9.69 g of 4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)dibenzofuran, 17 ml of 2M potassium carbonate aqueous solution, toluene 72 ml 18 ml of ethanol was added to a reaction vessel substituted with nitrogen, and nitrogen gas was supplied thereto for 30 minutes while irradiating the ultrasonic wave.

Next, add ruthenium (triphenylphosphine) palladium 0.54g

It was heated and stirred under reflux for 8.5 hours. After cooling to room temperature, 100 ml of heptane and 100 ml of water were added, and the precipitated crude product was taken by filtration.

The obtained crude product was purified by column chromatography (support: tannin extract, eluent: toluene/heptane), and then purified by using toluene to obtain 3,7-di(dibenzofuran-4). -yl)-10-(linked tris-2-phenyl)-10H-morphine The yellow powder (Compound 99) was 5.99 g (yield 51%).

The structure was identified using NMR for the obtained yellow powder. ^The results of ¹ H-NMR measurement are shown in Fig. 6.

The following 31 hydrogen signals were detected by ¹ H-NMR (THF-d ₈ ).

δ(ppm)=9.29(1H) 9.14(1H) 8.99(4H) 8.19(2H) 8.10(2H) 7.98(1H) 7.91-7.76(8H) 7.67-7.43(10H) 6.43(2H)

<Example 7>

(Measurement of glass transfer point)

The glass transition points were obtained by using a high-sensitivity differential scanning calorimeter (manufactured by Bruker AXS, DSC3100S) for the triazine derivatives obtained in Examples 1 to 4.

The results are shown below.

Because of this, the triazine derivative of the present invention has a glass transition point of 100 ° C or more, which is judged to indicate a stable film state.

<Example 8>

(evaluation of work function)

The benzene derivative obtained in each of Examples 1 to 3 was used, and a vapor deposited film (film thickness: 100 nm) of this compound was formed on an ITO substrate, and an atmospheric photoelectron spectroscope (manufactured by Riken Keiki Co., Ltd., AC-3 type) was used. ) Determine the work function. The results are as shown below.

From the above results, it is understood that the triazine derivative of the present invention exhibits an appropriate energy level and has a good electric power as compared with a work function 5.4 eV of a general hole transport material such as NPD or TPD. Hole transmission capability.

<Example 9>

(Evaluation of characteristics of organic EL elements)

An organic EL device having the hole transport layer formed of the biphenylene derivative (Compound 4) obtained in Example 1 and having the structure shown in Fig. 7 was produced.

Specifically, the glass substrate 1 on which ITO having a film thickness of 150 nm was formed was washed with an organic solvent, and then the surface was washed with oxygen plasma. Thereafter, the glass substrate 1 with the ITO electrode is attached to a vacuum vapor deposition machine, and the pressure inside the vapor deposition machine is reduced to 0.001 Pa or less. In this state, the compound 100 of the following structural formula is used to cover the transparent anode 2. In the manner, a hole injection layer 3 having a film thickness of 20 nm was formed.

On the hole injection layer 3 formed as described above, the triazine derivative (compound 4) obtained in Example 1 was vapor-deposited to form a hole transport layer 4 having a film thickness of 40 nm.

On the hole transport layer 4, a compound 101 of the following structural formula and a compound 102 of the following structural formula are subjected to binary vapor deposition at a vapor deposition rate of a compound 101: compound 102 = 5:95. The light-emitting layer 5 having a film thickness of 30 nm.

Next, an electron transport layer 6 having a film thickness of 30 nm was formed on the above-mentioned light-emitting layer 5 by using Alq ₃ .

Further, an electron injecting layer 7 having a film thickness of 0.5 nm was formed on the electron transporting layer 6 described above using lithium fluoride.

Finally, aluminum was vapor-deposited to form a cathode 8 with a film thickness of 150 nm, and an organic EL element having a structure as shown in Fig. 7 was obtained.

In the organic EL device produced as described above, the measurement results of the light-emitting characteristics when a DC voltage was applied to the atmosphere at room temperature were shown in Table 1.

<Comparative Example 1>

For comparison, an organic EL device was produced in the same manner as in Example 9 except that the compound 103 of the following structural formula was used instead of the triazine derivative of Example 1, and the hole transport layer 4 having a film thickness of 40 nm was formed.

The luminescent properties of the organic EL device obtained in this manner were measured in the same manner as in Example 9. The results are shown in Table 1.

As shown in Table 1, the driving voltage at the current of a current density of 10 mA/cm ² was 5.17 V of the organic EL device using the compound 103, and the organic EL device using the compound of Example 1 (Compound 4) was The power efficiency is 5.58 lm/W of the organic EL element using the compound 103, and the organic EL element using the compound of Example 1 (Compound 4) of the present invention is greatly improved by 6.52 lm/W. .

From the above results, it is apparent that the organic EL device using the triphenylene derivative of the present invention can achieve an improvement in luminous efficiency or electric power efficiency even when compared with an organic EL device using the above-mentioned compound 103 which is a known material. Or a reduction in the practical drive voltage.

[Industry Utilization]

The hydrazine derivative of the present invention has excellent hole transporting ability, excellent amorphous property, and stable film state, and therefore is excellent as a compound for an organic EL device. By using the compound to produce an organic EL device, high luminous efficiency and power efficiency can be obtained, and the practical driving voltage can be lowered, and durability can be improved. For example, the application to home electrochemical products or lighting can be carried out.

Claims (8)

A triazine derivative which is represented by the following formula (1): Wherein p and q each represent 0 or an integer from 1 to 4; s represents 0 or an integer from 1 to 3; and Ar ¹ and Ar ² each represent an aromatic hydrocarbon group or an aromatic heterocyclic group, but Ar ¹ and Ar ² may also be bonded to each other by a single bond or a methylene group having an substituent, an oxygen atom or a sulfur atom to form a ring; and R ¹ , R ² and R ³ each represent a halogen atom, a fluorine atom or a chlorine atom. , cyano group, nitro group, alkyl group having 1 to 6 carbon atoms, cycloalkyl group having 5 to 10 carbon atoms, alkenyl group having 2 to 6 carbon atoms, alkoxy group having 1 to 6 carbon atoms, carbon A cycloalkoxy group having an atomic number of 5 to 10, an aromatic hydrocarbon group, an aromatic heterocyclic group or an aryloxy group. The exemplified by the following formula (1a), as defined in the first application of the patent application: In the formula, p, q, s, Ar ¹ , Ar ² and R ¹ to R ³ are as defined in the above formula (1). The triazine derivative according to the first aspect of the patent application, wherein, in the formula (1), Ar ¹ and Ar ² together with a nitrogen atom form an indazole ring, an acridine ring or a phenol Ring or brown ring. An organic electroluminescent device having an organic layer of a pair of electrodes and at least one layer sandwiched therebetween, at least one layer of the organic layer containing a triazine derivative as in the first aspect of the patent application. The organic electroluminescence device of claim 4, wherein the organic layer containing the triazine derivative is a hole transport layer. The organic electroluminescence device according to claim 4, wherein the organic layer containing the triazine derivative is an electron blocking layer. The organic electroluminescence device according to claim 4, wherein the organic layer containing the triazine derivative is a hole injection layer. The organic electroluminescence device of claim 4, wherein the organic layer containing the triazine derivative is a light-emitting layer.