JP3999781B2 - Organic EL device - Google Patents

Description

The present invention relates to an organic EL (electroluminescence) element, and more particularly, relates to a element that emits light by applying an electric field to the multilayer structure film formed of an organic compound.

  An organic EL element has a configuration in which a thin film containing a fluorescent organic compound is sandwiched between a cathode and an anode, and excitons (excitons) are generated by injecting electrons and holes into the thin film and recombining them. It is an element that emits light by utilizing light emission (fluorescence / phosphorescence) when this exciton is deactivated.

The characteristics of the organic EL element are that it can emit surface light with a high luminance of about 100 to 10000 cd / m ² at a low voltage of about 10 V, and can emit light from blue to red by selecting the type of fluorescent material. That is.

On the other hand, the problems of the organic EL element are that the light emission life is short, the storage durability and the reliability are low.
(1) Physical changes in organic compounds (non-uniformity of the interface occurs due to crystal domain growth, etc., causing deterioration of charge injection capability, short-circuiting, and dielectric breakdown. Especially low molecular weight compounds with a molecular weight of 500 or less If used, the appearance and growth of crystal grains will occur and the film properties will be significantly reduced, and even if the interface of ITO etc. is rough, the appearance and growth of remarkable crystal grains will occur, resulting in a decrease in luminous efficiency and current leakage. (This also causes dark spots that are partially non-light emitting parts.)

(2) Oxidation / peeling of the cathode (Na, Mg, Al, etc. have been used as metals with a low work function to facilitate electron injection. These metals react with moisture and oxygen in the atmosphere. In other words, when the organic layer and the cathode are peeled off, it becomes impossible to inject the charge, especially when a film is formed by spin coating using a polymer compound or the like, and the residual solvent and decomposition products during the film formation promote the oxidation reaction of the electrode. The electrode is peeled off to cause a partial non-light emitting portion.)

(3) Low luminous efficiency and large calorific value (Because current flows through the organic compound, the organic compound must be placed under a high electric field strength, so it cannot escape from the heat generation. (Degradation / destruction of the device occurs due to melting, crystallization, thermal decomposition, etc.)

(4) Photochemical and electrochemical changes of the organic compound layer.

  In particular, with respect to blue light-emitting elements, there are few blue light-emitting materials that provide reliable and stable elements (for example, Non-Patent Document 1). In general, blue light-emitting materials have high crystallinity, for example, arylethene has high crystallinity despite high fluorescence quantum yield. Even if an element is manufactured using this compound as a light-emitting material, high luminance and A highly efficient and reliable device could not be provided. In addition, since the arylethene compounds reported so far are synthesized by the Wittig reaction, aromatic rings cannot be introduced into all ethene, resulting in low chemical stability and low molecular weight. The problem is that the amorphous structure of the thin film is low and it is easy to crystallize due to the presence of a stable structure of the conformation (for example, Patent Document 1).

Patent Document 2 discloses a diolefin compound in which three substituted triarylvinyl groups of an aryl group having 6 to 20 carbon atoms are linked via an arylene group having 6 to 20 carbon atoms. An organic EL device having a light emitting layer made of a diolefin compound has been proposed. Such a diolefin compound is obtained by making a diaryl halogenated methane Grignard, reacting this with dibenzoylaryl, and further dehydrating. For this reason, there are many side reaction residues, and there exists a fault which quenches fluorescence, when it uses for an EL element.
C. Adachi, et al., Appli. Phys. Lett., 56,799 (1990) JP-A-2-160894 JP-A-6-1000085

  The object of the present invention is to use a tetraarylethene derivative as an optical / electronic functional material that has little physical change, photochemical change, and electrochemical change, and has various emission colors with high reliability and luminous efficiency. An organic EL element having a blue emission color is realized. In particular, using an organic thin film formed by vapor deposition of a compound with a large molecular weight, high reliability with reduced drive voltage and reduced brightness, current leakage, and the appearance / growth of non-light emitting parts during device operation It is to realize a high-luminance light emitting element.

〔化１においてＡｒ_１、Ａｒ_２およびＡｒ_３は、各々芳香族残基を表し、これらは同一でも異なるものであってもよい。ｎは２〜６の整数である。Ｌ_０は、炭素数が２１以上のアリーレン基を表す。〕 Such an object is achieved by the present inventions (1) to (6) below.
( 1 ) An organic EL device having a light emitting layer containing a tetraarylethene derivative represented by the following chemical formula 1 .

_Ar 1, Ar ₂ and Ar ₃ in the chemical formula 1 each represent an aromatic residue, which may be different in the same. n is an integer of 2-6. L ₀ represents an arylene group having 21 or more carbon atoms. ]

〔化２において、Ｒ_１、Ｒ_２およびＲ_３は、各々、アルキル基、アリール基、アルコキシ基、アリーロキシ基またはアミノ基を表し、これらは同一でも異なるものであってもよい。ｓ、ｔおよびｕは、各々、０または１〜５の整数である。Ｌ_１１は、化１のＬ_０と同様である。ｎ１は２〜４の整数である。〕 ( 2 ) The organic EL device according to ( 1 ), wherein the aromatic residue represented by Ar ₁ , Ar ₂ or Ar ₃ is a phenyl group.
(3) Organic EL devices of the above tetraarylethene derivative is represented by the following formula 2 (1) or (2).

[In Chemical Formula 2 , R ₁ , R ₂ and R ₃ each represent an alkyl group, an aryl group, an alkoxy group, an aryloxy group or an amino group, and these may be the same or different. s, t, and u are each 0 or an integer of 1-5. L ₁₁ is the same as L ₀ in Chemical formula 1 . n1 is an integer of 2-4. ]

( 4 ) The above ( 4 ) further comprising at least one hole injection transport layer and at least one electron injection transport layer, wherein the light emitting layer is sandwiched between the hole injection transport layer and the electron injection transport layer ( Organic EL element in any one of 1 )-( 3 ).
( 5 ) Furthermore, it has at least one hole injection layer, at least one hole transport layer, and at least one electron injection transport layer, and the light emitting layer includes a hole transport layer, an electron injection transport layer, The organic EL element according to any one of the above ( 1 ) to ( 3 ), which is sandwiched between.
( 6 ) Furthermore, it has at least one hole injection layer, at least one hole transport layer, at least one electron injection layer, and at least one electron transport layer, and the light emitting layer transports holes. The organic EL element in any one of said ( 1 )-( 3 ) clamped by the layer and the electron carrying layer.

(Function)
In the organic EL device of the present invention, the tetraarylethene derivative represented by the above chemical formulas 1 to 3, preferably chemical formula 4 is appropriately selected and used for the organic compound layer, so that high luminance can be stably obtained. Further, it has high heat resistance and durability, and can be driven stably even when the element current density is about 100 mAcm ⁻² .

  Since the vapor-deposited film of the above-mentioned tetraarylethene derivative is in a stable amorphous state, the film physical properties are good and uniform light emission is possible without unevenness. Also, most compounds are stable for over a year in the atmosphere and do not cause crystallization.

  The organic EL device of the present invention emits light efficiently at a low driving voltage.

  In addition, the light emission maximum wavelength of the organic EL element of this invention is about 350-700 nm.

  The above-mentioned tetraarylethene derivative is obtained by Grignard aromatic residue trisubstituted halogenated ethene and cross-coupling with di-hexahalogenated aromatic compound or Grignard di-hexahalogenated aromatic compound. It is obtained by cross-coupling with a group III trisubstituted halogenated ethene. For this reason, a high purity product is obtained, and various reaction products can be obtained according to the purpose by appropriately selecting the starting materials.

  Moreover, when using the said compound for a light emitting layer among organic compound layers, about the thing whose carbon number of an arylene group is 21 or more among the tetraarylethene derivatives whose L is an arylene group (Formula 3, (See Chemical Formula 4). By setting the number of carbon atoms of the arylene group to 21 or more, stability in a thin film state is increased, and crystallization is further suppressed.

  JP-A-6-1000085 discloses a diolefin compound in which a triarylvinyl group substituted with three aryl groups having 6 to 20 carbon atoms is linked via an arylene group having 6 to 20 carbon atoms. An organic EL device having a light emitting layer made of this diolefin compound has been proposed. In this case, the diolefin compound partially overlaps with that of the present invention, but these compounds differ from the present invention in that diaryl halogenated methane is Grignarded and reacted with dibenzoylaryl to further dehydrate. Is gained by doing.

  Thus, when the arylene group of the linking group has 6 to 20 carbon atoms, the stability in a thin film state is slightly inferior when the light emitting material is used compared to those having 21 or more carbon atoms. The lifetime tends to be short, and the light emission luminance tends to decrease.

  In addition, what is obtained through the synthesis route described above has more impurities and lowers the stability of the thin film than the product obtained through the synthesis route in the present invention, and the lifetime of the device is shortened, resulting in lower emission luminance. To do.

Since the tetraarylethene derivative used in the present invention has a low crystallinity and can form a film having a good amorphous state, it is a compound for an organic EL device, specifically, a blue light emitting material, an electron injecting and transporting material, or a positive film. When used as a hole injecting and transporting material, the organic EL device of the present invention is a continuous emission light, and is a highly reliable device with little decrease in luminance and no occurrence of dark spots or current leaks. For example, when used in the light emitting layer, blue light emission with high luminance of 10,000 cd / m ² or more is possible.

  Hereinafter, a specific configuration of the present invention will be described in detail.

  The organic EL device of the present invention (hereinafter also referred to as “EL device”) has at least one organic compound layer, and at least one organic compound layer contains a tetraarylethene derivative represented by Chemical Formula 5. . A configuration example of the organic EL element of the present invention is shown in FIG. The organic EL element 1 shown in the figure has an anode 3, a hole injection / transport layer 4, a light emitting layer 5, an electron injection / transport layer 6, and a cathode 7 in this order on a substrate 2.

  The light emitting layer has a hole and electron injection function, a transport function thereof, and a function of generating excitons by recombination of holes and electrons. The hole injecting and transporting layer has the function of facilitating the injection of holes from the anode, the function of transporting holes and the function of hindering the transport of electrons, and the electron injecting and transporting layer prevents the injection of electrons from the cathode. It has a function to facilitate, a function to transport electrons, and a function to prevent the transport of holes, and these layers increase and confine holes and electrons injected into the light-emitting layer and optimize the recombination region. To improve luminous efficiency. The electron injecting and transporting layer and the hole injecting and transporting layer are provided as necessary in consideration of the height of each function of electron injection, electron transport, hole injection and hole transport of the compound used for the light emitting layer. For example, when the hole injection / transport function or electron injection / transport function of the compound used in the light-emitting layer is high, the light-emitting layer is not provided with the hole injection / transport layer or the electron injection / transport layer, but the hole injection / transport layer or the electron injection It can be set as the structure which serves as a transport layer. In some cases, neither the hole injection transport layer nor the electron injection transport layer may be provided. Further, each of the hole injecting and transporting layer and the electron injecting and transporting layer may be provided with a layer having an injection function and a layer having a transport function.

  Depending on the type of the compound, the tetraarylethene derivative represented by Chemical Formula 5 (hereinafter also referred to as “Compound of Chemical Formula 5”) may be used as a hole injecting / transporting compound having a hole injecting / transporting function. In addition, an electron injecting / transporting compound having a transporting function, and a relatively neutral compound can be appropriately used as a light emitting material.

  In addition, the recombination region and light emission can be controlled by controlling the film thickness while considering the carrier mobility and carrier density (determined by the ionization potential and electron affinity) of the light-emitting layer, electron injection transport layer, and hole injection transport layer to be combined. The region can be designed freely, and it is possible to design the light emission color, control the light emission luminance / light emission spectrum by the interference effect of both electrodes, and control the spatial distribution of light emission.

The tetraarylethene derivative of Chemical Formula 5 used in the present invention will be described. In Chemical Formula 5, Ar ₁ , Ar ₂ and Ar ₃ each represent an aromatic residue, and these may be the same or different.

Examples of the aromatic residue represented by Ar _{1 to} Ar ₃ include an aromatic hydrocarbon group (aryl group) and an aromatic heterocyclic group. The aromatic hydrocarbon group may be a monocyclic or polycyclic aromatic hydrocarbon group, and includes a condensed ring and a ring assembly. The aromatic hydrocarbon group preferably has a total carbon number of 6 to 30, and may have a substituent. In the case of having a substituent, examples of the substituent include an alkyl group, an aryl group, an alkoxy group, an aryloxy group, and an amino group. This substituent will be described later. Examples of the aromatic hydrocarbon group include a phenyl group, an alkylphenyl group, an alkoxyphenyl group, an arylphenyl group, an aryloxyphenyl group, an aminophenyl group, a biphenyl group, a naphthyl group, an anthryl group, a pyrenyl group, and a perylenyl group. It is done.

  The aromatic heterocyclic group preferably includes O, N, and S as a hetero atom, and may be a 5-membered ring or a 6-membered ring. Specific examples include a thienyl group, a furyl group, a pyrrolyl group, and a pyridyl group.

As the aromatic residue represented by Ar _{1 to} Ar ₃ , a phenyl group is particularly preferable.

  n is an integer of 2 to 6, and preferably an integer of 2 to 4.

  L represents an n-valent aromatic residue, and in particular, 2 to 6 valences derived from aromatic hydrocarbons, aromatic heterocycles, aromatic ethers (including aromatic thioethers) or aromatic amines, particularly 2 It is preferably a tetravalent residue. These aromatic residues may further have a substituent.

Of these, when a light emitting material is used, L is an oxy group (—O—), a thio group (—S—), an imino group (—NR ₀ —: R ₀ is an aryl group), a heterocyclic diyl group. , An arylene group in which one or more of an alkenylene group and an alkylene group are interposed, an arylene group having 21 or more carbon atoms, preferably 21 to 100, more preferably 24 to 50, and a trivalent to hexavalent aromatic hydrocarbon Residue or aromatic heterocycle, aromatic ether or aromatic amine that is a divalent to hexavalent residue, that is, a compound represented by Chemical Formula 2 (In Chemical Formula 5, L ₀ represents the above L). Is preferred.

  Of the chemical formula 5, the tetraarylethene derivative represented by the chemical formula 6 is preferable.

化６について説明すると、Ｒ_１、Ｒ_２およびＲ_３は、各々、アルキル基、アリール基、アルコキシ基、アリーロキシ基またはアミノ基を表し、これらは同一でも異なるものであってもよい。

Referring to Chemical Formula 6, R ₁ , R ₂ and R ₃ each represent an alkyl group, an aryl group, an alkoxy group, an aryloxy group or an amino group, which may be the same or different.

The alkyl group represented by R _{1 to} R ₃ is preferably an alkyl group having 1 to 10 carbon atoms, which may be linear or branched, and further has a substituent. Examples thereof include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, and a t-butyl group.

The aryl group represented by R _{1 to} R ₃ is preferably an aryl group having 6 to 20 carbon atoms and may have a substituent. For example, a phenyl group, an o-tolyl group, an m-tolyl group, p -A tolyl group, a naphthyl group, an anthryl group, etc. are mentioned.

The alkoxy group represented by R ₁ to R _3, it preferably has 1 to 6 carbon atoms in the alkyl group moiety of the alkoxy group include a methoxy group, an ethoxy group, t-butoxy group and the like.

Examples of the aryloxy group represented by R _{1 to} R ₃ include a phenoxy group, a 4-methylphenoxy group, and a 4- (t-butyl) phenoxy group.

The amino group represented by R _{1 to} R ₃ preferably has a substituent, and examples thereof include a dimethylamino group, a diethylamino group, a diphenylamino group, and a bis (biphenyl) amino group.

s, t and u are each an integer of 0 or 1 to 5. When s, t and u are integers of 2 or more, R _{1 s} , R _{2 s} , and R _{3 s} are the same or different. It may be a thing.

  In the chemical formula 6, each of s, t and u is preferably 0 or 1, particularly preferably 0, that is, an unsubstituted phenyl group.

L ₁ is an arylene group, an arenetriyl group, an arenetetrayl group, a heterocyclic diyl group, a heterocyclic triyl group, a heterocyclic tetrayl group, a triarylamine or a multimeric diyl group, a triarylamine or a multimer thereof A triyl group, a triarylamine or a multimer thereof, a tetrayl group, an aryl-substituted heterocyclic diyl group, an aryl-substituted heterocyclic triyl group, or an aryl-substituted heterocyclic tetrayl group. These may be further substituted. The arylene group, arenetriyl group, and arenetetrayl group represented by L ₁ are an oxy group (—O—), a thio group (—S—), an imino group (—NR ₀ —: R ₀ is a phenyl group, etc. Aryl group), a heterocyclic diyl group, an alkenyl group, and an alkylene group may be interposed.

Such an arylene group, arenetriyl group, and arenetetrayl group preferably have a total carbon number of 6 or more, more preferably 21 or more, particularly 21 to 100, and more particularly 24 to 50. Specific examples of the arylene group represented by L ₁ include a phenylene group, a biphenylene group, a naphthylene group, a diphenyletherdiyl group, a diphenylthioetherdiyl group, a diphenylmethyldiyl group, a diphenyloxadiazolediyl group, and a terphenylene group. It is done. Examples of the arenetriyl group include a benzenetriyl group and a quaterphenyltriyl group. Examples of the arenetetrayl group include a tetraphenylethenetetrayl group. Such a group may be substituted with a phenylethylyl group or the like.

The heterocyclic diyl group represented by L ₁ includes a thiophene diyl group, a furandiyl group, a pyridinediyl group, a bithiophenediyl group, a bifurandiyl group, a bipyridinediyl group, a pyrazinediyl group, a pyrrolediyl group, a bipyrrolediyl group, a quinolinediyl group, an oxaline group. Examples thereof include a diazole diyl group, a quinoxaline diyl group, and a diphenylquinoxaline diyl group. Examples of the heterocyclic triyl group include an isoquinoline triyl group, and examples of the heterocyclic tetrayl group include a quinoxaline tetrayl group. These groups may further have a substituent such as a methoxy group.

Examples of the triarylamine represented by L ₁ or a diyl group of the multimer include a triphenylamine diyl group, and the triarylamine of the triarylamine or the multimer thereof includes a triphenylamine triyl group. Can be mentioned. Examples of the triylamine or multimer tetrayl group include N, N′-tetraphenyl-4,4′-diamino-1,1′-biphenyltetrayl group. In addition, the multimer of triarylamine is usually about 2 to 4 mer.

Examples of the aryl-substituted heterocyclic diyl group represented by L ₁ include a diphenyloxadiazole diyl group, and examples of the aryl-substituted heterocyclic triyl group include a diphenyloxadiazole triyl group and a diphenylquinoxaline triyl group. Examples of the aryl-substituted heterocyclic tetrayl group include a diphenylquinoxaline tetrayl group.

Preferred examples of L ₁ are shown below, but the present invention is not limited thereto.

In formula 6, n1 is dependent on the valence of _{L 1,} is an integer of 2 to 4, further 2,3, and particularly preferably from 2.

In addition, as L ₁ when used as a hole injecting and transporting compound, heterocyclic diyl group, heterocyclic triyl group, heterocyclic tetrayl group, triarylamine derivative diyl group, triarylamine derivative triyl group, triarylamine derivative It is preferably an arylene group, an arenetriyl group or an arenetetrayl group which may be intervened by a tetrayl group or an imino group (—NR ₀ —: R ₀ is an aryl group).

In addition, as L ₁ when used as an electron injecting and transporting compound, one or more of an oxy group (—O—), a thio group (—S—), a heterocyclic diyl group, and an alkylene group are present. Arylene group, arenetriyl group or arenetetrayl group, heterocyclic diyl group, heterocyclic triyl group, heterocyclic tetrayl group, aryl-substituted heterocyclic diyl group, aryl-substituted heterocyclic triyl group, or aryl-substituted heterocyclic tetrayl It is preferably a group.

In addition, as L ₁ when used as a light emitting material, an oxy group (—O—), a thio group (—S—), an imino group (—NR ₀ —: R ₀ is an aryl group), a heterocyclic diyl group, an alkenylene An arylene group in which one or more of a group and an alkylene group are present, an arylene group having 21 or more carbon atoms, more preferably 21 to 100, and particularly preferably 24 to 50 carbon atoms, an oxy group (—O—), a thio group ( —S—), an imino group (—NR ₀ : R ₀ is an aryl group), a heterocyclic diyl group, an alkenylene group, and an alkylene group, an arenetriyl group or an arenetetrayl group that may be interposed. , Heterocyclic diyl group, heterocyclic triyl group, heterocyclic tetrayl group, triarylamine or multimeric diyl group, triarylamine or multimeric triyl group, Rear benzidine or tetrayl group multimers thereof, aryl-substituted heterocyclic diyl group, those wherein aryl substituted heterocyclic triyl group, or an aryl-substituted heterocyclic tetrayl group, i.e., the compounds (Formula 4, represented by Formula 4, L ₁₁ Represents L ₁ above).

Preferred examples of such tetraarylethene derivatives are shown below, but the present invention is not limited thereto. Chemical formula 13 is a general formula, and chemical formula 14 to chemical formula 21 are shown by using chemical formula 13 display. R _{11 to} R ₁₅ , R _{21 to} R ₂₅ , and R _{31 to} R ₃₅ are all H, when hydrogen, and only one of them is a substituent. In addition, the attribute of a compound is described collectively. In the case of a hole-injecting / transporting compound, n is used, and in the case of an electron-injecting / transporting compound, e is used. Of these compounds, compound No. 1 can be used as a blue light emitting material. 1-4, 14, 21, 23-26, 32, 42, 43, 47-59 and the like.

The tetraarylethene derivative of the present invention is
(1) A dihalogenated aryl derivative using a Ni complex such as NiCl ₂ (dppp) [dppp: diphenylphosphinopropane] by grinding an aromatic residue trisubstituted halogenated ether such as a halogenated triphenylethene compound. A method of cross-coupling with di-, tri-, tetra-, penta- or hexahalogenated aromatic compounds such as
(2) Di-, tri-, tetra-, penta- or hexa-halogenated aromatic compounds such as dihalogenated aryl derivatives are Grignarded, and aromatics such as halogenated triphenylethene derivatives using Ni complexes such as NiCl ₂ (dppp) It can be synthesized using a method of cross-coupling with a residue trisubstituted halogenated ethene.

The compound thus synthesized can be identified by elemental analysis, mass spectrometry, infrared absorption spectrum, ¹ H nuclear magnetic resonance absorption (NMR) spectrum, and the like.

  The tetraarylethene derivative of Chemical formula 5 used in the present invention has a molecular weight of about 500 to 2000, a high melting point of 200 to 350 ° C, and a glass transition temperature (Tg) of 80 to 250 ° C. Accordingly, a smooth and good film in an amorphous state that is transparent and stable even at room temperature or higher is formed by ordinary vacuum deposition or the like, and the good film state is maintained for a long period of time.

  The case where the compound of Chemical formula 5 is used in the light emitting layer will be described. In addition to the compound of Chemical formula 5, other fluorescent materials may be used for the light emitting layer. Examples of other fluorescent materials include compounds disclosed in Japanese Patent Application Laid-Open No. 63-264692, for example, Quinacridone, rubrene, styryl dyes and at least one compound selected from compounds such as metal complex dyes such as tris (8-quinolinolato) aluminum. The content of such a fluorescent substance is preferably 5 mol% or less of the compound of Chemical formula 5. By appropriately selecting and adding such a compound, emitted light can be shifted to the long wavelength side.

  The light emitting layer may contain a singlet oxygen quencher. Examples of such quenchers include nickel complexes, rubrene, diphenylisobenzofuran, and tertiary amines. The content of such a quencher is preferably 10 mol% or less of the compound of Chemical formula 5.

  When the compound of Chemical formula 5 is used for the light emitting layer, the hole injection transport layer and the electron injection transport layer may be made of various organic compounds used in ordinary organic EL devices, such as JP-A 63-295695. Various organic compounds described in Kaihei 2-191694, JP-A-3-792, and the like can be used. For example, an aromatic tertiary amine, a hydrazone derivative, a carbazole derivative, a triazole derivative, an imidazole derivative, an oxadiazole derivative having an amino group, or the like can be used for the hole injecting and transporting layer. Can be used organometallic complex derivatives such as aluminum quinolinol, oxadiazole derivatives, pyridine derivatives, pyrimidine derivatives, quinoline derivatives, quinoxaline derivatives, diphenylquinone derivatives, perylene derivatives, nitro-substituted fluorene derivatives, and the like.

  When the hole injecting and transporting layer is divided into a hole injecting layer and a hole transporting layer, a preferred combination can be selected from the compounds for the hole injecting and transporting layer. At this time, it is preferable to laminate in order of a compound layer having a small ionization potential from the anode (ITO or the like) side. Further, it is preferable to use a compound having a good thin film property on the anode surface. For example, a vapor deposition film of 8 or more oligothiophenes or polythiophenes is used as a hole injection and ITO surface modification layer, and tetraphenyldiaminobiphenyl derivative (TPD) or Compound No. 3 is preferably used as the hole transport layer. In the case of making an element, since vapor deposition is used, a thin film of about 1 to 10 nm can be made uniform and pinhole-free, so even if various compounds are used, the efficiency due to the color tone change and reabsorption of the emitted color Can be prevented.

  When the electron injecting and transporting layer is divided into an electron injecting layer and an electron transporting layer, a preferred combination can be selected from the compounds for the electron injecting and transporting layer. At this time, it is preferable to laminate in the order of the layer of the compound having a large electron affinity value from the cathode side. Such a stacking order is the same when two or more electron injecting and transporting layers are provided.

  In the present invention, the light emitting layer is preferably a mixed layer of an electron injecting and transporting compound and a hole injecting and transporting compound. And the compound of Chemical formula 5 is contained in such a mixed layer. When the compound of Chemical formula 5 is contained as a fluorescent substance, more specifically, when the compound of Chemical formula 5 is an electron injecting and transporting compound, it is preferable to add another hole injecting and transporting compound. When the compound 5 is a hole injecting and transporting compound, it is preferable to further add another electron injecting and transporting compound. The mixing ratio of the electron injecting and transporting compound and the hole injecting and transporting compound in the mixed layer is a weight ratio, and the ratio of the electron injecting and transporting compound to the hole injecting and transporting compound is 60:40 to 40:60. Is particularly preferable, and it is preferably about 50:50.

  The electron injecting and transporting compound to be provided to the mixed layer is selected from the above compounds for the electron injecting and transporting layer, and the hole injecting and transporting compound is selected from the above compounds for the hole injecting and transporting layer. Can be used. Moreover, depending on the case, you may select and use from the compound of Chemical formula 5, and you may comprise a mixed layer with the compounds of Chemical formula 5. Furthermore, in the mixed layer, each of the electron injecting and transporting compound and the hole injecting and transporting compound may be used alone or in combination of two or more. The mixed layer may be doped with a compound of Chemical Formula 5 or another fluorescent substance in order to increase the emission intensity.

  Furthermore, a mixed layer of another electron injecting and transporting compound and another hole injecting and transporting compound may be used, and such a mixed layer may be used by doping the compound of Chemical Formula 5.

  By applying such a mixed layer to an EL element, the stability of the element is improved.

  Next, the case where the compound of Chemical formula 5 is used for the hole injecting and transporting layer will be described. When the compound of Chemical formula 5 is used for the hole injecting and transporting layer, the fluorescent substance used for the light emitting layer may be selected from those having a longer wavelength fluorescence than the compound of Chemical formula 5, for example, What is necessary is just to select suitably from 1 or more types of the fluorescent substance used together with the compound of 5. In such a case, the compound of Chemical formula 5 can also be used for the light emitting layer. Moreover, the compound of Chemical formula 5 can also be used in a light emitting layer that also serves as a hole injecting and transporting layer.

  Furthermore, the case where the compound of Chemical formula 5 is used for the electron injecting and transporting layer will be described. In this case, the fluorescent substance used for the light emitting layer may be a substance having fluorescence with a wavelength longer than or equal to that of the compound of Chemical formula 5. For example, a fluorescent material that can be used in combination with the compound of Chemical formula 5 in the light emitting layer described above can be selected and used. In addition, the compound of Chemical formula 5 can be used in the light emitting layer in such a configuration. Moreover, the compound of Chemical formula 5 can also be used in a light emitting layer which also serves as an electron injecting and transporting layer.

  In addition, in the above, when other fluorescent substances are mainly used in the light emitting layer, the compound of Chemical formula 5 may be added as a fluorescent substance in an amount of 10 mol% or less and used in combination.

  The thickness of the light emitting layer, the thickness of the hole injecting and transporting layer, and the thickness of the electron injecting and transporting layer are not particularly limited, and may vary depending on the forming method, but is usually about 5 to 1000 nm, and particularly 8 to 200 nm. preferable.

  The thickness of the hole injecting and transporting layer and the thickness of the electron injecting and transporting layer may be about the same as the thickness of the light emitting layer or about 1/10 to 10 times depending on the design of the recombination / light emitting region. When the injection layer and the transport layer for electrons or holes are separated, the injection layer is preferably 1 nm or more, and the transport layer is preferably 10 nm or more. The upper limit of the thickness of the injection layer and the transport layer at this time is usually about 20 nm for the injection layer and about 100 nm for the transport layer.

  For the cathode, it is preferable to use a material having a low work function, such as Li, Na, Mg, Al, Ag, In, or an alloy containing one or more of these materials. Further, the cathode preferably has fine crystal grains, and particularly preferably in an amorphous state. The thickness of the cathode is preferably about 10 to 1000 nm.

In order to cause the EL element to emit light, at least one of the electrodes needs to be transparent or translucent, and as described above, the cathode material is limited, so that the transmittance of emitted light is preferably 80% or more. It is preferable to determine the material and thickness of the anode so that Specifically, for example, ITO, SnO ₂ , Ni, Au, Pt, Pd, polypyrrole doped with a dopant, or the like is preferably used for the anode. The anode thickness is preferably about 10 to 500 nm. Moreover, in order to improve the reliability of an element, it is necessary for a drive voltage to be low, However As a preferable thing, 10-30 ohms / square ITO is mentioned.

  The substrate material is not particularly limited, but in the illustrated example, a transparent or translucent material such as glass or resin is used to extract emitted light from the substrate side. Further, the emission color may be controlled by using a color filter film or a dielectric reflection film on the substrate.

  Note that when an opaque material is used for the substrate, the stacking order shown in FIG. 1 may be reversed.

  Next, the manufacturing method of the organic EL element of this invention is demonstrated.

  The cathode and the anode are preferably formed by vapor deposition such as vapor deposition or sputtering.

  For the formation of the hole injecting and transporting layer, the light emitting layer, and the electron injecting and transporting layer, it is preferable to use a vacuum deposition method because a homogeneous thin film can be formed. When the vacuum deposition method is used, a homogeneous thin film having an amorphous state or a crystal grain size of 0.1 μm or less (usually 0.005 μm or more) can be obtained. If the crystal grain size exceeds 0.1 μm, non-uniform light emission occurs, the drive voltage of the element must be increased, and the charge injection efficiency is also significantly reduced.

Although the conditions of vacuum deposition are not specifically limited, It is preferable to set it as the vacuum degree of 10 < ^-3 > Pa or less, and to set a vapor deposition rate to about 0.1-1 nm / sec. Moreover, it is preferable to form each layer continuously in a vacuum. If formed continuously in a vacuum, impurities can be prevented from adsorbing to the interface of each layer, so that high characteristics can be obtained. In addition, the driving voltage of the element can be lowered.

  In the case of using a vacuum deposition method for forming each of these layers, when a plurality of compounds are contained in one layer, it is preferable to co-deposit each boat containing the compounds by individually controlling the temperature.

  The EL element of the present invention is usually used as a direct current drive type EL element, but can be alternating current driven or pulse driven. The applied voltage is usually about 2 to 20V.

  Hereinafter, specific examples of the present invention will be shown together with comparative examples, and the present invention will be described in more detail.

<Example 1>
Compound No. Synthesis of 1 To 0.488 g (20 mmol) of magnesium activated under argon in a Schlenk flask, 50 ml of a tetrahydrofuran (THF) solution of 6.70 g (20 mmol) of 2-bromo-1,1,2-triphenylethene was added dropwise. It became Grignard. To this reaction solution, 0.3 g of NiCl ² (dppe) and 3.02 g (9.4 mmol) of 4,4′-dibromobiphenyl were added and refluxed at 60 ° C. for 4 hours. This reaction solution was poured into a 1N aqueous hydrochloric acid solution, extracted with toluene, washed with water, and dried over magnesium sulfate. After the solvent was distilled off, recrystallization from acetone / dichloromethane gave 3.0 g of a white solid exhibiting blue fluorescence.

  1.0 g of this white solid was purified by sublimation to obtain 0.8 g of a pure solid.

Mass spectrometry: m / e 662 (M +)
Elemental analysis: C H Br
Calculated value /% 94.22 5.78 0.0
Measurement /% 94.31 5.54 0.0
Infrared absorption spectrum: Fig. 2
¹ H-NMR spectrum (270 MHz): FIG.
Differential scanning calorimetry (DSC): melting point 304 ° C., glass transition temperature 110 ° C.
Ionization potential: 5.90 eV

<Example 2>
Compound No. Synthesis of 2 To 0.485 g (20 mmol) of magnesium activated under argon in a Schlenk flask, 50 ml of a THF solution of 6.70 g (20 mmol) of 2-bromo-1,1,2-triphenylethene was added dropwise to form a Grignard. . To this reaction solution, 0.4 g of NiCl ₂ (dppe) and 2.35 g (10 mmol) of 1,4-dibromobenzene were added and refluxed at 60 ° C. for 4 hours. This reaction solution was poured into a 1N aqueous hydrochloric acid solution, extracted with toluene, washed with water, and dried over magnesium sulfate. After the solvent was distilled off, recrystallization from acetone / dichloromethane gave 3.0 g of a white solid exhibiting blue fluorescence.

  1.0 g of this white solid was purified by sublimation to obtain 0.8 g of a pure solid.

Mass spectrometry: m / e 586 (M +)
Elemental analysis: C H Br
Calculated value /% 94.16 5.84 0.0
Measurement /% 94.15 5.53 0.0
Infrared absorption spectrum: Fig. 4
¹ H-NMR spectrum: FIG.
Differential scanning calorimetry (DSC): melting point 250 ° C., glass transition temperature 83 ° C.
Ionization potential: 5.95 eV

<Example 3>
Compound No. Synthesis of 3 To 0.488 g (20 mmol) of magnesium activated under argon in a Schlenk flask, 50 ml of a THF solution of 6.70 g (20 mmol) of 2-bromo-1,1,2-triphenylethene was added dropwise to make a Grignard. . To this reaction solution, 0.3 g of NiCl ₂ (dppe) and 3.00 g (6.0 mmol) of 4,4 ′, 4 ″ -tribromotriphenylamine were added and refluxed for 4 hours at 60 ° C. This reaction solution was 1N. The solution was poured into an aqueous hydrochloric acid solution, extracted with toluene, washed with water, dried over magnesium sulfate, evaporated, and recrystallized from acetone / dichloromethane to obtain 3.0 g of a yellowish white solid exhibiting blue-green fluorescence.

  1.0 g of this white solid was purified by sublimation to obtain 0.8 g of a pure solid.

Mass spectrometry: m / e 1007 (M +)
Elemental analysis: C H N Br
Calculated value /% 92.91 5.69 1.39 0.0
Measured value /% 92.46 5.32 1.29 0.0
Infrared absorption spectrum: FIG.
¹ H-NMR spectrum (270 MHz): 7
Differential scanning calorimetry (DSC): melting point 300 ° C., glass transition temperature 129 ° C.
Ionization potential: 5.45 eV

<Example 4>
Compound No. Synthesis of 7 To 0.485 g (20 mmol) of magnesium activated under argon in a Schlenk flask, 50 ml of a THF solution of 6.70 g (20 mmol) of 2-bromo-1,1,2-triphenylethene was added dropwise to form a Grignard. . To this reaction solution, 0.4 g of NiCl ₂ (dppe) and 2.07 g (6.6 mmol) of 1,3,5-tribromobenzene were added and refluxed at 60 ° C. for 4 hours. The reaction solution was poured into 1N aqueous hydrochloric acid solution, extracted with toluene, washed with water, and dried over magnesium sulfate. After distilling off the solvent, the residue was recrystallized from acetone / hexane and purified by silica column using toluene / hexane as a developing solvent to obtain 1.0 g of a white solid exhibiting blue fluorescence.

  0.5 g of this white solid was purified by sublimation to obtain 0.3 g of a pure solid.

Mass spectrometry: m / e 840 (M +)
Infrared absorption spectrum: FIG.
¹ H-NMR spectrum (270 MHz): FIG.
Differential scanning calorimetry (DSC): melting point 213 ° C., glass transition temperature 92 ° C.
Ionization potential: 5.95 eV

<Example 5>
Compound No. Synthesis of 8 To 0.485 g (20 mmol) of magnesium activated under argon in a Schlenk flask, 50 ml of a THF solution of 2.42 g (10 mmol) of 2,5-dibromothiophene was added dropwise to form a Grignard. To this reaction solution, 0.4 g of NiCl ₂ (dppe) and 6.70 g (20 mmol) of 1,2-bromo-1,1,2-triphenylethene were added and refluxed at 60 ° C. for 4 hours. The reaction solution was poured into 1N aqueous hydrochloric acid solution, extracted with toluene, washed with water, and dried over magnesium sulfate. After distilling off the solvent, 1.0 g of a yellow solid showing green fluorescence was obtained after recrystallization from acetone / hexane.

  1.0 g of this yellow solid was purified by sublimation to obtain 0.8 g of a pure solid.

Mass spectrometry: m / e 592 (M +)
Elemental analysis: C H S Br
Calculated value /% 89.15 5.44 5.41 0.0
Measured value /% 89.05 5.32 5.05 0.0
Ionization potential: 5.40 eV

In addition, it identified with the said compound also from the result of the infrared absorption spectrum and the < ¹ > H-NMR spectrum.

<Example 6>
Compound No. Synthesis of 19 To 0.485 g (20 mmol) of magnesium activated under argon in a Schlenk flask, 50 ml of a THF solution of 6.70 g (20 mmol) of 2-bromo-1,1,2-triphenylethene was dropped to form a Grignard. . To this reaction solution, 0.4 g of NiCl ₂ (dppe) and 4.40 g (20 mmol) of 2,3-bis (4-bromophenyl) quinoxaline were added and refluxed at 60 ° C. for 4 hours. The reaction solution was poured into a 0.1N hydrochloric acid aqueous solution, extracted with chloroform, washed with water, and dried over magnesium sulfate. After the solvent was distilled off, recrystallization from acetone gave 3.0 g of a yellow solid exhibiting green fluorescence.

  1.0 g of this yellow solid was purified by sublimation to obtain 0.8 g of a pure solid.

Mass spectrometry: m / e 790 (M +)
Elemental analysis: C H N
Calculated value /% 91.10 5.35 3.54
Measurement /% 91.03 5.28 3.40
Infrared absorption spectrum: FIG.
¹ H-NMR spectrum: FIG.
Ionization potential: 5.98 eV

<Example 7>
Compound No. Synthesis of 4 Synthesis was performed in the same manner as in Example 1 except that 2.95 g (9 mmol) of bis (p-bromophenyl) ether was used instead of 3.02 g (9.4 mmol) of 4,4′-dibromobiphenyl.

Mass spectrometry: m / e 678 (M +)
Infrared absorption spectrum: FIG.
¹ H-NMR spectrum: FIG.
Differential scanning calorimetry (DSC): melting point 254 ° C., glass transition temperature 90 ° C.
The measured values of elemental analysis agreed well with the calculated values.

<Example 8>
Compound No. Synthesis of 33 Synthesis of N, N ′-(bis (4-bromophenyl) -N, N′-diphenyl-4,4′-diaminobiphenyl 16.8 g (50 mmol) of N, N′-diphenylbenzidine and 4-iodo 42.4 g (150 mmol) of bromobenzene, 0.2 g of activated copper powder, and 20.7 g (150 mmol) of potassium carbonate were put into a 200 ml eggplant flask, and stirred for 24 hours at 200 ° C. after N ₂ substitution.

  100 ml of toluene was added, the organic layer was extracted and washed 3 times with water. Silica column chromatography purification was performed 3 times using a mixed solvent of toluene and hexane as an extraction solvent, and recrystallization from hexane / dichloromethane gave 15.2 g of white crystals having blue fluorescence.

  Compound No. Into a synthetic Schlekk flask No. 33, 50 ml of THF solution of 6.7 g (20 mmol) of 2-bromo-1,1,2-triphenylethene was added dropwise to 0.485 g (20 mmol) of magnesium activated under argon to form Grignard. did.

To this reaction solvent, 0.4 g of NiCl ₂ (dppe) and 5.82 g (9 mmol) of N, N′-bis (4-bromophenyl) -N, N′-diphenyl-4,4′-diaminobiphenyl were added. Refluxed at ˜70 ° C. for 4 hours.

  The reaction solution was poured into a 10% aqueous hydrochloric acid solution, extracted with toluene and chloroform, washed with water, and dried over magnesium sulfate. After the solvent was distilled off, the residue was washed with acetone and purified by column chromatography using a mixed solvent of toluene and hexane as a developing solvent to obtain 3.0 g of a yellowish white solid having greenish yellow fluorescence.

  1.0 g of this yellow solid was purified by sublimation to obtain 0.7 g of a pure solid.

Mass spectrometry: m / e 996 (M +)
Infrared absorption spectrum: FIG.
¹ H-NMR spectrum: FIG.
Differential scanning calorimetry (DSC): melting point 333 ° C., glass transition temperature 132 ° C.
Ionization potential: 5.38 eV
The measured values of elemental analysis agreed well with the calculated values.

<Example 9>
Compound No. Synthesis of 42 Synthesis of 9,10-bis (p-bromophenyl) anthracene From 4-iodobromobenzene and butyllithium (hexane solution) in 4.16 g (20 mmol) of anthraquinone and 100 ml of toluene in a 260 ml flask under argon Synthesized. An ether solution of 6.52 g (40 mmol) of 4-bromophenyllithium was added dropwise. After stirring at room temperature for 24 hours, 100 ml of water was added dropwise. The precipitate was filtered to obtain a diol form.

  This diol was dissolved in 100 ml of acetic acid, a hydrochloric acid solution of 2.0 g of tin dichloride was added dropwise, stirred at 100 ° C. for 1 hour, extracted with toluene, and washed 5 times with water. After drying over magnesium sulfate, the solvent was distilled off and purified by silica column chromatography using toluene and hexane as extraction solvents.

  Thereafter, it was recrystallized with toluene to obtain 1 g of white crystals exhibiting blue fluorescence.

  Compound No. Synthesis of 42, instead of 5.82 g (9 mmol) of N, N′-bis (p-bromophenyl) -N, N′-diphenyl-4,4′-aminobiphenyl, 9,10-bis (p-bromophenyl) ) Synthesis was performed in the same manner as in Example 8 using 4.40 g (9 mmol) of anthracene.

Mass spectrometry: m / e 838 (M +)
Infrared absorption spectrum: FIG.
¹ H-NMR spectrum: FIG.
Differential scanning calorimetry (DSC): melting point 370 ° C., glass transition temperature 143 ° C.
The measured values of elemental analysis agreed well with the calculated values.

<Example 10>
Compound No. Synthesis of 65 Synthesis was performed in the same manner as in Example 1 except that 2.5 g (9 mmol) of 2,6-dichloro-3methoxyacridine was used instead of 3.02 g (9.4 mmol) of 4,4′-dibromobiphenyl. .

Mass spectrometry: m / e 716 (M +)
Infrared absorption spectrum: FIG.
¹ H-NMR spectrum: FIG.
Differential scanning calorimetry (DSC): melting point 259.2 ° C., glass transition temperature 132.6 ° C.
The measured values of elemental analysis agreed well with the calculated values.

Other exemplary compounds shown in Chemical formulas 13 to 23 were also synthesized according to Examples 1 to 10. These compounds were identified from the results of elemental analysis, mass spectrometry, infrared absorption spectrum, and ¹ H-NMR spectrum.

<Example 11>
A glass substrate having an ITO transparent electrode (anode) with a thickness of 100 nm is ultrasonically cleaned with a neutral detergent, acetone, and ethanol, and is lifted from boiling ethanol and dried, and fixed to a substrate holder of a vapor deposition apparatus. The pressure was reduced to 1 × 10 ⁻⁴ Pa.

  Next, N, N′-diphenyl-N, N′-m-tolyl-4,4′-diamino-1,1′-biphenyl (TPD-1) was deposited to a thickness of 50 nm at a deposition rate of 0.2 nm / sec. It vapor-deposited and it was set as the positive hole injection transport layer.

  Subsequently, the compound No. 1 of Example 1 was used. 1 was deposited to a thickness of 50 nm to form a light emitting layer.

  Next, while maintaining the reduced pressure state, tris (8-quinolinolato) aluminum was deposited as an electron injecting and transporting layer to a thickness of 10 nm at a deposition rate of 0.2 nm / sec.

  Further, while maintaining the reduced pressure state, MgAg (weight ratio 10: 1) was vapor-deposited at a vapor deposition rate of 0.2 nm / sec to a thickness of 200 nm to form a cathode to obtain an organic EL device.

When a voltage was applied to the organic EL element and a current was passed, blue light of 8500 cd / m ² (light emission maximum wavelength λmax = 485 nm) was confirmed at 19 V, 155 mA / cm ² , and this light emission was in a dry nitrogen atmosphere. It was stable for over 200 hours. There was no emergence or growth of partially non-light emitting parts. The half life of the luminance was 10 hours when driven at a constant current of 10 mA / cm ² .

<Example 12>
A glass substrate having an ITO transparent electrode (anode) with a thickness of 100 nm is ultrasonically cleaned with a neutral detergent, acetone, and ethanol, and is lifted from boiling ethanol and dried, and fixed to a substrate holder of a vapor deposition apparatus. The pressure was reduced to 1 × 10 ⁻⁴ Pa.

  Next, poly (thiophene-2,5-diyl) was deposited to a thickness of 10 nm to form a hole injection layer.

  Next, N, N′-diphenyl-N, N′-m-tolyl-4,4′-diamino-1,1′-biphenyl (TPD-1) was deposited to a thickness of 50 nm at a deposition rate of 0.2 nm / sec. It vapor-deposited and it was set as the positive hole transport layer.

  Subsequently, the compound No. 1 of Example 1 was used. 1 was deposited to a thickness of 50 nm to form a light emitting layer.

  Next, while maintaining the reduced pressure state, tris (8-quinolinolato) aluminum was deposited as an electron injecting and transporting layer to a thickness of 10 nm at a deposition rate of 0.2 nm / sec.

  Further, while maintaining the reduced pressure state, MgAg (weight ratio 10: 1) was vapor-deposited at a vapor deposition rate of 0.2 nm / sec to a thickness of 200 nm to form a cathode to obtain an organic EL device.

When a voltage was applied to the organic EL element and a current was applied, 15000 cd / m ² of blue light (maximum light emission wavelength λmax = 485 nm) was confirmed at 16 V, 325 mA / cm ² , and this light emission was in a dry nitrogen atmosphere. And stable for over 1000 hours. There was no emergence or growth of partially non-light emitting parts. The half life of the luminance was 100 hours when driven at a constant current of 10 mA / cm ² .

<Example 13>
A device was produced in the same manner as in Example 12. However, N, N, N ′, N′-tetrakis (3-biphenyl) -4,4′-diamino-1,1′-biphenyl (TPD-2) was used instead of the hole transport material TPD-1. .

When a voltage was applied to the organic EL element and a current was passed, 11500 cd / m ² of blue light (maximum light emission wavelength λmax = 485 nm) was confirmed at 18 V, 475 mA / cm ² , and this light emission was in a dry nitrogen atmosphere. And stable for over 1000 hours. There was no emergence or growth of partially non-light emitting parts. The half life of the luminance was 200 hours when driven at a constant current of 10 mA / cm ² .

<Example 14>
A glass substrate having an ITO transparent electrode (anode) with a thickness of 100 nm is ultrasonically cleaned with a neutral detergent, acetone, and ethanol, and is lifted from boiling ethanol and dried, and fixed to a substrate holder of a vapor deposition apparatus. The pressure was reduced to 1 × 10 ⁻⁴ Pa.

  Next, poly (thiophene-2,5-diyl) was deposited to a thickness of 10 nm to form a hole injection layer.

  Next, N, N′-diphenyl-N, N′-m-tolyl-4,4′-diamino-1,1′-biphenyl (TPD-1) was deposited to a thickness of 50 nm at a deposition rate of 0.2 nm / sec. It vapor-deposited and it was set as the positive hole transport layer.

  Subsequently, Compound No. 2 of Example 2 was used. 2 was deposited to a thickness of 50 nm to form a light emitting layer.

  Next, while maintaining the reduced pressure state, tris (8-quinolinolato) aluminum was deposited as an electron injecting and transporting layer to a thickness of 10 nm at a deposition rate of 0.2 nm / sec.

  Further, while maintaining the reduced pressure state, MgAg (weight ratio 10: 1) was vapor-deposited at a vapor deposition rate of 0.2 nm / sec to a thickness of 200 nm to form a cathode to obtain an organic EL device.

When a voltage was applied to this organic EL element and a current was passed, blue light emission of 8000 cd / m ² (light emission maximum wavelength λmax = 485 nm) was confirmed at 15 V, 300 mA / cm ² , and this light emission was in a dry nitrogen atmosphere. And stable for over 100 hours. There was no emergence or growth of partially non-light emitting parts. The half life of the luminance was 20 hours with a constant current drive of 10 mA / cm ² .

<Example 15>
A glass substrate having an ITO transparent electrode (anode) with a thickness of 100 nm is ultrasonically cleaned with a neutral detergent, acetone, and ethanol, and is lifted from boiling ethanol and dried, and fixed to a substrate holder of a vapor deposition apparatus. The pressure was reduced to 1 × 10 ⁻⁴ Pa.

  Next, poly (thiophene-2,5-diyl) was deposited to a thickness of 10 nm to form a hole injection layer.

  Next, N, N′-diphenyl-N, N′-m-tolyl-4,4′-diamino-1,1′-biphenyl (TPD-1) was deposited to a thickness of 50 nm at a deposition rate of 0.2 nm / sec. It vapor-deposited and it was set as the positive hole transport layer.

  Subsequently, compound No. 3 of Example 3 was used. 3 was deposited to a thickness of 50 nm to form a light emitting layer.

  Next, while maintaining the reduced pressure state, tris (8-quinolinonato) aluminum was deposited as an electron injecting and transporting layer to a thickness of 10 nm at a deposition rate of 0.2 nm / sec.

  Further, while maintaining the reduced pressure state, MgAg (weight ratio 10: 1) was vapor-deposited at a vapor deposition rate of 0.2 nm / sec to a thickness of 200 nm to form a cathode to obtain an organic EL device.

When a voltage was applied to this organic EL element and a current was passed, 345 cd / m ² of blue-green light (maximum light emission wavelength λmax = 450 nm) was confirmed at 14 V, 53 mA / cm ² , and this light emission was in a dry nitrogen atmosphere. It was stable for over 1000 hours. There was no emergence or growth of partially non-light emitting parts. The half life of the luminance was 200 hours when driven at a constant current of 10 mA / cm ² .

<Example 16>
In Example 12, the compound No. Instead of using compound 1, compound no. An organic EL device was obtained in the same manner except that 42 was used.
When a voltage was applied to this organic EL element and a current was passed, 8020 cd / m ² of blue light (maximum light emission wavelength λmax = 470 nm) was confirmed at 15 V, 450 mA / cm ² , and this light emission was in a dry nitrogen atmosphere. It was stable for over 3000 hours. There was no emergence or growth of partially non-light emitting parts. The half life of the luminance was 300 hours when driven at a constant current of 10 mA / cm ² .

<Example 17>
In Example 12, the compound No. Instead of using compound 1, compound no. An organic EL device was obtained in the same manner except that 49 was used.
When a voltage was applied to the organic EL element and a current was passed, 18000 cd / m ² of blue light (maximum light emission wavelength λmax = 480 nm) was confirmed at 14 V, 340 mA / cm ² , and this light emission was in a dry nitrogen atmosphere. It was stable for over 5000 hours. There was no emergence or growth of partially non-light emitting parts. The half life of the luminance was 500 hours when driven at a constant current of 10 mA / cm ² .

<Example 18>
In Example 12, the compound No. Instead of using compound 1, compound no. An organic EL device was obtained in the same manner except that 53 was used.

When a voltage was applied to the organic EL element and a current was passed, 9040 cd / m ² of blue light (maximum light emission wavelength λmax = 470 nm) was confirmed at 16 V, 300 mA / cm ² , and this light emission was in a dry nitrogen atmosphere. And stable for over 1000 hours. There was no emergence or growth of partially non-light emitting parts. The half life of the luminance was 200 hours when driven at a constant current of 10 mA / cm ² .

<Example 19>
In Example 12, after forming the light emitting layer, tris (8-quinolinolato) aluminum was evaporated to a thickness of 20 nm at a deposition rate of 0.2 nm / sec to form an electron transport layer. Next, tetrabutyldiphenoquinone was deposited to a thickness of 10 nm to form an electron injection layer. Thereafter, an organic EL device was obtained in the same manner as in Example 12.

When a voltage was applied to this organic EL element and a current was passed, 4500 cd / m ² of blue light (maximum light emission wavelength λmax = 480 nm) was confirmed at 13 V, 105 mA / cm ² , and this light emission was in a dry nitrogen atmosphere. And stable for over 1000 hours. There was no emergence or growth of partially non-light emitting parts. The half life of the luminance was 50 hours with a constant current drive of 10 mA / cm ² .

<Example 20>
A glass substrate having an ITO transparent electrode (anode) with a thickness of 100 nm is ultrasonically cleaned with a neutral detergent, acetone, and ethanol, and is lifted from boiling ethanol and dried, and fixed to a substrate holder of a vapor deposition apparatus. The pressure was reduced to 1 × 10 ⁻⁴ Pa.

  Subsequently, Compound No. 7 was deposited at a deposition rate of 0.2 nm / sec to a thickness of 50 nm to form a hole injecting and transporting layer.

  Next, tris (8-quinolinolato) aluminum was vapor-deposited to a thickness of 50 nm to form a light emitting layer that also served as an electron injecting and transporting layer.

  Further, while maintaining the reduced pressure state, MgAg (weight ratio 10: 1) was vapor-deposited at a vapor deposition rate of 0.2 nm / sec to a thickness of 200 nm to form a cathode to obtain an organic EL device.

When a voltage was applied to this organic EL element and a current was passed, 1759 cd / m ² of green light emission (maximum light emission wavelength λmax = 500 nm) was confirmed at 11 V, 525 mA / cm ² , and this light emission was in a dry nitrogen atmosphere. And stable for over 1000 hours. There was no emergence or growth of partially non-light emitting parts. The half life of luminance was 400 hours.

<Example 21>
In Example 20, the compound No. Instead of using compound 7, compound no. An organic EL device was obtained in the same manner except that 8 was used.

When a voltage was applied to this organic EL element and a current was passed, 4000 cd / m ² of green light (maximum light emission wavelength λmax = 520 nm) was confirmed at 13 V, 300 mA / cm ² , and this light emission was in a dry nitrogen atmosphere. And stable for over 1000 hours. There was no emergence or growth of partially non-light emitting parts. The half life of the luminance was 50 hours with a constant current drive of 10 mA / cm ² .

<Example 22>
In Example 20, the compound No. Instead of using compound 7, compound no. An organic EL device was obtained in the same manner except that 33 was used.

When a voltage was applied to this organic EL element and a current was passed, 12000 cd / m ² of blue-green light (maximum light emission wavelength λmax = 503 nm) was confirmed at 12 V, 525 mA / cm ² , and this light emission was in a dry nitrogen atmosphere. It was stable for 4000 hours or more. There was no emergence or growth of partially non-light emitting parts. The half life of the luminance was 500 hours when driven at a constant current of 10 mA / cm ² .

<Example 23>
A glass substrate having an ITO transparent electrode (anode) with a thickness of 100 nm is ultrasonically cleaned with a neutral detergent, acetone, and ethanol, and is lifted from boiling ethanol and dried, and fixed to a substrate holder of a vapor deposition apparatus. The pressure was reduced to 1 × 10 ⁻⁴ Pa.

  Next, poly (thiophene-2,5-diyl) was deposited to a thickness of 10 nm to form a hole injection layer.

  Next, N, N′-diphenyl-N, N′-m-tolyl-4,4′-diamino-1,1′-biphenyl (TPD-1) was deposited to a thickness of 50 nm at a deposition rate of 0.2 nm / sec. It vapor-deposited and it was set as the positive hole transport layer.

  Next, tris (8-quinolinolato) aluminum was vapor-deposited at a deposition rate of 0.2 nm / sec to a thickness of 50 nm to form a light emitting layer.

  Next, while maintaining the reduced pressure state, as an electron injecting and transporting layer, Compound No. 6 of Example 6 was used. 19 was deposited to a thickness of 10 nm at a deposition rate of 0.2 nm / sec.

  Further, while maintaining the reduced pressure state, MgAg (weight ratio 10: 1) was vapor-deposited at a vapor deposition rate of 0.2 nm / sec to a thickness of 200 nm to form a cathode to obtain an organic EL device.

When a voltage was applied to the organic EL element and a current was passed, 15000 cd / m ² of blue-green light (maximum light emission wavelength λmax = 495 nm) was confirmed at 14 V, 300 mA / cm ² , and this light emission was in a dry nitrogen atmosphere. It was stable for 500 hours or more. There was no emergence or growth of partially non-light emitting parts. The half life of the luminance was 200 hours when driven at a constant current of 10 mA / cm ² .

<Example 24>
In Example 23, the compound No. Instead of using compound 19, compound no. An organic EL device was obtained in the same manner except that 16 was used.

When a voltage was applied to this organic EL element and a current was passed, 18000 cd / m ² of green light (maximum light emission wavelength λmax = 500 nm) was confirmed at 12 V, 450 mA / cm ² , and this light emission was in a dry nitrogen atmosphere. And stable for over 1000 hours. There was no emergence or growth of partially non-light emitting parts. The half life of the luminance was 400 hours when driven at a constant current of 10 mA / cm ² .

<Example 25>
After forming the hole transport layer in the same manner as in Example 12, TPD-1 and the compound No. 1 in Example 1 were used. 1 was deposited to a thickness of 20 nm at a deposition rate of 0.2 nm / sec to form a light emitting layer. In this case, TPD-1 and Compound No. The ratio to 1 was 1: 1 by weight.

  Subsequently, Compound No. Except for using 1, an electron injecting and transporting layer was formed in the same manner as in Example 12, and a cathode was formed in the same manner to obtain an organic EL device.

When a voltage was applied to the organic EL element and a current was applied, 12000 cd / m ² of blue light (maximum light emission wavelength λmax = 480 nm) was confirmed at 12 V, 250 mA / cm ² , and this light emission was in a dry nitrogen atmosphere. It was stable for over 5000 hours. There was no appearance and growth of a partial non-light emitting portion, and no current leakage was observed. The half life of the luminance was 1000 hours when driven at a constant current of 10 mA / cm ² .

  In Examples 11 to 25, one or more of the compounds of the present invention listed in Chemical Formulas 13 to 23 are selected as appropriate, and a light emitting layer, an electron injecting and transporting layer or a hole is combined in a combination other than the above examples. When used for the injecting and transporting layer, the same results as in the above examples were obtained depending on the layer structure of the organic EL element.

<Comparative Example 1>
A glass substrate having an ITO transparent electrode (anode) with a thickness of 100 nm is ultrasonically cleaned with a neutral detergent, acetone, and ethanol, and is lifted from boiling ethanol and dried, and fixed to a substrate holder of a vapor deposition apparatus. The pressure was reduced to 1 × 10 ⁻⁴ Pa.

  Next, N, N′-bis (-m-methylphenyl) -N, N′-diphenyl-1,1′-biphenyl-4,4′-diamine was vapor-deposited to a thickness of 50 nm, and a hole injection transport layer was formed. It was.

  Next, while maintaining the reduced pressure state, 1,3-bis (5- (4-t-butylphenyl) -1,3,4-oxadiazo-2-yl) benzene (OXD-7) was deposited at a deposition rate of 0.2 nm. The film was deposited to a thickness of 50 nm at / sec to form an electron injection transport / light emitting layer.

  Further, while maintaining the reduced pressure state, MgAg (weight ratio 10: 1) was vapor-deposited at a vapor deposition rate of 0.2 nm / sec to a thickness of 200 nm to form a cathode to obtain an organic EL device.

When a voltage was applied to the organic EL element and a current was passed, 550 cd / m ² of blue light (maximum light emission wavelength λmax = 480 nm) was confirmed at 14 V, 127 mA / cm ² , and this light emission was in a dry nitrogen atmosphere. In 10 hours, the appearance and growth of a partial non-light emitting portion was observed, and dielectric breakdown occurred in 20 hours. The half life of the brightness was 20 minutes.

<Comparative example 2>
Similar to this document, using 1,1,4,4-tetraphenyl-1,3-butadiene described in C. Adachi et al., Appli. Phys. Lett., 56, 799 (1990) in the light emitting layer. An organic EL element having the structure was assembled. That is, in Comparative Example 1, after forming a hole injecting and transporting layer, the above compound was similarly deposited to a thickness of 50 nm to form a light emitting layer. Thereafter, tris (8-quinolinolato) aluminum was deposited at a deposition rate of 0.2 nm / sec to a thickness of 10 nm to form an electron injecting and transporting layer, and a cathode was formed in the same manner as in Comparative Example 1 to obtain an organic EL device.

  In this organic EL element, the organic layer was crystallized, and when a voltage was applied to both electrodes, the organic EL element was in a short-circuited state and clear light emission was not obtained.

<Comparative Example 3>
In Comparative Example 2, an organic EL device having the same configuration was obtained except that t-butylphenylbiphenyloxadiazole (PBD) was used as the electron injecting and transporting layer.

  This organic EL element was short-circuited 1 hour after fabrication, and when a voltage was applied in this state, blue light emission was seen but dielectric breakdown occurred.

<Comparative Example 4>
In accordance with the method of Synthesis Example 1 of JP-A-6-1000085, diphenylchloromethane is converted into Grignard, reacted with 1,4-dibenzoylbenzene, dehydrated in the presence of formic acid, and compound No. 1 is obtained. 2 was obtained.

  Thus obtained compound No. An organic EL device was obtained in the same manner as in Example 14 except that 2 was used for the light emitting layer.

  The characteristics of this organic EL element were examined in the same manner as in Example 14. As a result, only about half the luminance was obtained with the same drive current value.

  In obtaining the above EL element, the stability of the vapor deposition film of the compound of Chemical formula 5 and the compound used in the comparative example was examined. An example of these is shown below.

<Example 26>
Compound No. 1 obtained in Example 1 was obtained. 1 was vacuum-deposited on a glass substrate under a reduced pressure of 10 ⁻⁵ Pa or less to form a 1000 A-thick deposited film.

  This deposited film was a transparent amorphous film in the initial stage, and did not crystallize for about one month even when left in the atmosphere.

<Example 27>
Compound No. obtained in Example 2 2 was used to form a deposited film in the same manner as in Example 26, and the stability of the film was examined in the same manner as in Example 26. As a result, the film was not crystallized for about 10 days.

<Comparative Example 5>
Compound No. 1 obtained according to Synthesis Example 1 of JP-A-6-1000085. 2 was used to form a vapor-deposited film in the same manner as in Example 26, and the stability of the film was examined in the same manner as in Example 26. As a result, the film was initially amorphous but crystallized after one day. did.

<Example 28>
For the compounds (Nos. 3, 7, 8, 16, 19, 33, 42, 49, 53), vapor-deposited films of the respective compounds were formed in the same manner as in Example 26, and the stability of each film was similarly examined. However, it was found that the initial amorphous state was maintained even after being left in the atmosphere for over a year.

It is a side view which shows the structural example of the EL element of this invention. It is a graph which shows the infrared absorption spectrum of the tetraarylethene derivative used for this invention. It is a graph which shows the NMR spectrum of the tetraarylethene derivative used for this invention. It is a graph which shows the infrared absorption spectrum of the tetraarylethene derivative used for this invention. It is a graph which shows the NMR spectrum of the tetraarylethene derivative used for this invention. It is a graph which shows the infrared absorption spectrum of the tetraarylethene derivative used for this invention. It is a graph which shows the NMR spectrum of the tetraarylethene derivative used for this invention. It is a graph which shows the infrared absorption spectrum of the tetraarylethene derivative used for this invention. It is a graph which shows the NMR spectrum of the tetraarylethene derivative used for this invention. It is a graph which shows the infrared absorption spectrum of the tetraarylethene derivative used for this invention. It is a graph which shows the NMR spectrum of the tetraarylethene derivative used for this invention. It is a graph which shows the infrared absorption spectrum of the tetraarylethene derivative used for this invention. It is a graph which shows the NMR spectrum of the tetraarylethene derivative used for this invention. It is a graph which shows the infrared absorption spectrum of the tetraarylethene derivative used for this invention. It is a graph which shows the NMR spectrum of the tetraarylethene derivative used for this invention. It is a graph which shows the infrared absorption spectrum of the tetraarylethene derivative used for this invention. It is a graph which shows the NMR spectrum of the tetraarylethene derivative used for this invention. It is a graph which shows the infrared absorption spectrum of the tetraarylethene derivative used for this invention. It is a graph which shows the NMR spectrum of the tetraarylethene derivative used for this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Organic EL element 2 Substrate 3 Anode 4 Hole injection transport layer 5 Light emitting layer 6 Electron injection transport layer 7 Cathode

Claims (6)

An organic EL device having a light emitting layer containing a tetraarylethene derivative represented by the following chemical formula 1 .

_Ar 1, Ar ₂ and Ar ₃ in the chemical formula 1 each represent an aromatic residue, which may be different in the same. n is an integer of 2-6. L ₀ represents an arylene group having 21 or more carbon atoms. ] The organic EL device according to claim 1 the aromatic residues represented by _Ar 1, Ar ₂ or Ar ₃ is a phenyl group. The organic EL device according to claim 1 or 2 tetraarylethene derivative is represented by the following formula 2.

[In Chemical Formula 2 , R ₁ , R ₂ and R ₃ each represent an alkyl group, an aryl group, an alkoxy group, an aryloxy group or an amino group, and these may be the same or different. s, t, and u are each 0 or an integer of 1-5. L ₁₁ is the same as L ₀ in Chemical formula 1 . n1 is an integer of 2-4. ] Further comprising a at least one layer hole injecting and transporting layer of at least one layer of electron injecting and transporting layer of the light emitting layer is a hole injection transport layer and the claims that are sandwiched between the electron injection transport layer 1-3 Organic EL element of any one of these. Furthermore, it has at least one hole injection layer, at least one hole transport layer, and at least one electron injection transport layer, and the light emitting layer is sandwiched between the hole transport layer and the electron injection transport layer. The organic EL device according to any one of claims 1 to 3 . Furthermore, it has at least one hole injection layer, at least one hole transport layer, at least one electron injection layer, and at least one electron transport layer. the organic EL device according to any one of claims 1 to 3 which is sandwiched by the transport layer.

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