Organic electroluminescent element

Abstract

An object of the present application is to provide an organic EL element having a capping layer composed of a material having the following properties: (1) high light absorption coefficient, (2) high refractive index, (3) good stability of thin film, (4) excellent durability, (5) excellent light resistance, and (6) no absorption in the respective wavelength regions of blue, green, and red. Since the arylamine-based material having a specific structure of the present application is excellent in stability of thin film and durability, an amine compound having a specific benzoxazole ring structure and a high refractive index is selected as a material constituting the capping layer, and an organic EL element using the material having a high absorbance at a wavelength of 400 nm to 410 nm in an absorption spectrum at a concentration of 10 ‑5 mol / L shows good element characteristics.

Description

TECHNICAL FIELD

[0001] The present application relates to a compound and an element suitable for an organic electroluminescent element (hereinafter referred to as an organic EL element) as a self-light-emitting element suitable for various display devices, and in detail, to an amine compound having a benzoxazole ring structure and an organic EL element using the same.

[0002] This application claims priority based on Japanese Patent Application No. 2020-023986 filed in Japan on February 17, 2020, the contents of which are incorporated herein. BACKGROUND

[0003] Since the organic EL element is a self-light-emitting element, it is brighter and has excellent visibility compared to a liquid crystal element, and can display vividly, so active research has been conducted.

[0004] In 1987, C. W. Tang et al. of Eastman Kodak Company developed a layered structure element in which various roles are shared to each material. As a result, an organic EL element using an organic material became a practical element. They stacked a fluorescent body capable of transporting electrons and an organic layer capable of transporting holes, and injected charges of both into the layer of the fluorescent body to make it emit light. As a result, 1000 cd / m2 was obtained using a voltage of 10 V or less. Since then, research and development of an organic EL element have been actively conducted. 2 The above high brightness (for example, refer to Patent Document 1 and Patent Document 2).

[0005] So far, in order to put the organic EL element into practical use, many improvements have been made. For example, various roles of the layered structure were further subdivided. Then, an organic EL element 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 provided on a substrate was manufactured. This organic EL element has a bottom emission structure that emits light from the bottom, and thus high efficiency and durability are achieved (for example, refer to Non-Patent Document 1).

[0006] In recent years, a metal having a high work function is used for an anode, and a light-emitting element using a top emission structure that emits light from the upper portion is gradually used. In the bottom emission structure that takes out light from the bottom portion having a pixel circuit, the area of the light-emitting portion is limited, and in contrast, in the light-emitting element of the top emission structure, since light is taken out from the upper portion, the pixel circuit is not blocked, and thus has an advantage that the light-emitting portion can be made wide. In the light-emitting element of the top emission structure, a semi-transparent electrode such as LiF / Al / Ag (for example, refer to Non-Patent Document 2), Ca / Mg (for example, refer to Non-Patent Document 3), LiF / MgAg, and the like is used for a cathode.

[0007] In such a light-emitting element, in a case where light emitted from the light-emitting layer is incident on another film, if the light is incident at an angle of equal to or higher than a certain angle, the light is totally reflected at the interface between the light-emitting layer and the other film. Thus, only a part of the emitted light can be utilized. In recent years, in order to improve the light extraction efficiency, a light-emitting element provided with a "capping layer" having a high refractive index on the outside of a semitransparent electrode having a low refractive index has been proposed (see Non-Patent Documents 2 and 3, for example).

[0008] As for the effect of the capping layer in a light-emitting element of a top emission structure, it is confirmed using a light-emitting element in which Ir(ppy)3 is used as a light-emitting material. In the light-emitting element, the current efficiency is 38 cd / A in the case where there is no capping layer, and is 64 cd / A in the case where ZnSe having a film thickness of 60 nm is used as the capping layer. It is seen that the efficiency is improved by about 1.7 times. In addition, it is shown that the maximum point of the transmittance of the semitransparent electrode and the capping layer does not necessarily coincide with the maximum point of the efficiency, and that the maximum point of the light extraction efficiency is determined by the interference effect (see Non-Patent Document 3, for example).

[0009] In the past, in order to form the capping layer, the use of a metal mask having high precision has been proposed, but since the metal mask is deformed by heat in use at a high temperature, there is a problem of a decrease in the alignment precision. Thus, in the case of ZnSe, the melting point is as high as 1100 °C or higher (see Non-Patent Document 3, for example), and in a metal mask having high precision, evaporation cannot be performed at a correct position, which can have an influence on the light-emitting element itself. Furthermore, even film formation by a sputtering method can have an influence on the light-emitting element, and thus a capping layer using an inorganic substance as a constituent material is not suitable for use.

[0010] In addition, as a capping layer for adjusting the refractive index, an example using tris(8-hydroxyquinoline)aluminum (hereinafter referred to as Alq3) is described (see Non-Patent Document 2, for example). Alq3 is known to be an organic EL material that is commonly used as a green light-emitting material or an electron-transporting material. However, Alq3 has a weak absorption near 450 nm, which is used for a blue light-emitting material, and thus in the case of a blue light-emitting element including a capping layer containing Alq3, there are problems of a decrease in color purity and a decrease in the light extraction efficiency.

[0011] In addition, in a light-emitting element manufactured using a conventional capping layer, there is a problem that light having a wavelength of 400 nm to 410 nm of sunlight passes through, has an influence on the materials in the inside of the element, and decreases the color purity and the light extraction efficiency.

[0012] In order to improve the element properties of an organic EL element, as a material for the cap layer, a material that absorbs light of a wavelength of 400 nm to 410 nm of sunlight, and does not affect the materials inside the element is particularly required. In addition, in order to greatly improve the light extraction efficiency, as a material for the cap layer, a material having a high absorption coefficient, a high refractive index, and excellent thin film stability and durability is required.

[0013] Prior Art Documents

[0014] Patent Documents

[0015] Patent Document 1: Japanese Patent Application Laid-Open (JP-A) No. 8-048656

[0016] Patent Document 2: Japanese Patent (JP-B) No. 3194657

[0017] Patent Document 3: International Publication No. 2014 / 009310

[0018] Patent Document 4: International Publication No. 2013 / 038627

[0019] Non-Patent Documents

[0020] Non-Patent Document 1: Preprints of the 9th Workshop on Applied Physics, pp. 55-61 (2001)

[0021] Non-Patent Document 2: Appl. Phys. Lett., 78, 544 (2001)

[0022] Non-Patent Document 3: Appl. Phys. Lett., 82, 466 (2003)

[0023] Non-Patent Document 4: J. Org. Chem., 71, 1802 (2006)

[0024] Non-Patent Document 5: J. Org. Chem., 60, 7508 (1995)

[0025] Non-Patent Document 6: Synth. Commun., 11, 513 (1981)

[0026] Non-Patent Document 7: Appl. Phys. Lett., 98, 083302 (2011) SUMMARY

[0027] PROBLEMS TO BE SOLVED BY THE INVENTION

[0028] The present application aims at improving the element characteristics of an organic EL element, particularly, at absorbing light of wavelengths of 400 nm to 410 nm of sunlight without affecting the materials inside the element, and at greatly improving the light extraction efficiency, by providing an organic EL element having a cap layer composed of a material having the following characteristics.

[0029] (1) high light absorption coefficient,

[0030] (2) high refractive index,

[0031] (3) good stability of thin film,

[0032] (4) excellent durability,

[0033] (5) excellent light resistance,

[0034] (6) material having no absorption in the wavelength region of each of cyan, green and red.

[0035] The material suitable for the cap layer of the present application has the following physical characteristics.

[0036] (1) high light absorption coefficient,

[0037] (2) high refractive index,

[0038] (3) vapor deposition,

[0039] (4) stable thin film state,

[0040] (5) high glass transition temperature.

[0041] Further, the element suitable for the present application has the following physical characteristics.

[0042] (1) absorption of light of 400 nm to 410 nm,

[0043] (2) high light extraction efficiency,

[0044] (3) no decrease in color purity,

[0045] (4) light transmission without change over time,

[0046] (5) long life.

[0047] Means for solving the problem

[0048] Therefore, the present inventors, in order to achieve the above object, focused on the fact that arylamine-based materials are excellent in stability and durability of thin film. An amine compound having a specific benzoxazole ring structure and a high refractive index was selected to have a concentration of 10 -5The benzoxazole ring structure shown here refers to a structure in which a benzene ring is fused with an oxazole that is a 5-membered heterocycle containing one or more nitrogen atoms. An organic EL element in which this compound is used as a material constituting a capping layer was manufactured, and the characteristics of the element were evaluated in depth, and as a result, the present application was completed.

[0049] That is, according to the present application, the following organic EL element is provided.

[0050] 1) An organic electroluminescent element which is an organic electroluminescent element having, in order, an anode, a hole transport layer, a light-emitting layer, an electron transport layer, a cathode, and a capping layer, characterized in that the refractive index of a material of the capping layer is 1.90 or greater at a wavelength of 500 nm to 570 nm, and the capping layer contains an amine compound represented by the following general formula (1).

[0051] [Chemical Formula 1]

[0052]

[0053] (In the formula, R1 to R5 can be the same as or different from each other, and represent a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, a linear or branched alkyl group having 1 to 6 carbon atoms which can have a substituent, a cyclic alkyl group having 5 to 10 carbon atoms which can have a substituent, a linear or branched alkenyl group having 2 to 6 carbon atoms which can have a substituent, a linear or branched alkoxy group having 1 to 6 carbon atoms which can have a substituent, a cyclic alkoxy group having 5 to 10 carbon atoms which can have a substituent, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, a substituted or unsubstituted condensed polycyclic aromatic group, or a substituted or unsubstituted aryloxy group,

[0054] In the case where R1 to R4 exist in plurality respectively, a ring can be formed between the plurality of adjacent ones.

[0055] X represents an oxygen atom, a sulfur atom, or a nitrogen atom,

[0056] Y and Z represent an oxygen atom or a sulfur atom.

[0057] In the case where X is an oxygen atom or a sulfur atom, X does not have R5.

[0058] Each Ar can be the same as or different from each other, and represents a divalent group of a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, or a substituted or unsubstituted condensed polycyclic aromatic group.

[0059] r1 to r3 represent an integer of 0 to 4,

[0060] r4 represents an integer of 0 to 3.

[0061] 2) The organic electroluminescent device according to the above item 1), characterized in that the amine compound is represented by the following General Formula (la).

[0062] [Chem. 2]

[0063]

[0064] (In the formula, R1to R5, X, Y, Z, r1to r4are as defined in the General Formula (1).)

[0065] 3) The organic electroluminescent device according to the above item 1) or 2), characterized in that r1to r4in the General Formula (1) are 0.

[0066] 4) The organic electroluminescent device according to any one of the above items 1) to 3), wherein a thickness of the capping layer is in a range of 30 nm to 120 nm.

[0067] 5) A method of manufacturing the organic electroluminescent device according to any one of the above items 1) to 4).

[0068] As "aromatic hydrocarbon group", "aromatic heterocyclic group" or "condensed polycyclic aromatic group" in "substituted or unsubstituted aromatic hydrocarbon group", "substituted or unsubstituted aromatic heterocyclic group" or "substituted or unsubstituted condensed polycyclic aromatic group" represented by R1to R5, Ar in General Formula (1) or (la), "aromatic hydrocarbon group" is a ring structure which is composed of only carbon atoms and shows non-condensed aromaticity; "aromatic heterocyclic group" is a ring structure which shows aromaticity and contains one or more kinds of atoms other than carbon in the atoms constituting the ring; "condensed polycyclic aromatic group" is a ring structure which is composed of only carbon atoms and is condensed with a plurality of aromatic rings. Specifically, as "aromatic hydrocarbon group", phenyl group, biphenyl group, terphenyl group and the like can be exemplified, and in addition to them, aryl groups having a ring structure showing aromaticity which is not condensed and having a carbon atom number of 6 to 30 can be exemplified. As "aromatic heterocyclic group", pyridyl group, pyrimidyl group, triazinyl group, furanyl group, pyrrolyl group, thienyl group, quinolyl group, isoquinolyl group, benzofuranyl group, benzothienyl group, indolyl group, carbazolyl group, benzoxazolyl group, benzothiazolyl group, quinoxalyl group, benzimidazolyl group, pyrazolyl group, dibenzofuranyl group, dibenzothienyl group, naphthylidene group, phenanthrolinyl group, acridinyl group, carbolinyl group and the like can be exemplified, and in addition to them, heteroaryl groups having a carbon atom number of 2 to 20 can be exemplified. As "condensed polycyclic aromatic group", naphthyl group, anthryl group, phenanthryl group, fluorenyl group, spirobifluorenyl group, indenyl group, pyrenyl group, perylenyl group, fluoranthenyl group, triphenylenyl group and the like can be exemplified, and in addition to them, aryl groups having a ring structure condensed with a plurality of aromatic rings and having a carbon atom number of 6 to 30 can be exemplified.

[0069] As "a linear or branched alkyl group having 1 to 6 carbon atoms which can have a substituent", "a cycloalkyl group having 5 to 10 carbon atoms which can have a substituent", "a linear or branched alkenyl group having 2 to 6 carbon atoms which can have a substituent", "a linear or branched alkoxy group having 1 to 6 carbon atoms which can have a substituent", "a cycloalkoxy group having 5 to 10 carbon atoms which can have a substituent", or "a substituted or unsubstituted aryloxy group" represented by R1to R5in General Formula (1) or (1a), specifically, as "a linear or branched alkyl group having 1 to 6 carbon atoms", there can be mentioned methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, n-pentyl group, isopentyl group, neopentyl group, n-hexyl group, and the like. As "a cycloalkyl group having 5 to 10 carbon atoms", there can be mentioned cyclopentyl group, cyclohexyl group, 1-adamantyl group, 2-adamantyl group, and the like. As "a linear or branched alkenyl group having 2 to 6 carbon atoms", there can be mentioned vinyl group, allyl group, isopropenyl group, 2-butenyl group, and the like. As "a linear or branched alkoxy group having 1 to 6 carbon atoms", there can be mentioned methoxy group, ethoxy group, n-propoxy group, and the like. As "a cycloalkoxy group having 5 to 10 carbon atoms", there can be mentioned cyclopentyloxy group, cyclohexyloxy group, 1-adamantyloxy group, and the like. As "an aryloxy group", there can be mentioned phenoxy group, tolyloxy group, and biphenylyloxy group, and the like.

[0070] As the "substituent" of "substituted aromatic hydrocarbon group", "substituted aromatic heterocyclic group", "substituted condensed polycyclic aromatic group", "linear or branched alkyl group having 1 to 6 carbon atoms which can have a substituent", "cycloalkyl group having 5 to 10 carbon atoms which can have a substituent", or "linear or branched alkenyl group having 2 to 6 carbon atoms which can have a substituent" represented by R1to R5or Ar in General Formula (1) or (1a), specifically, in addition to deuterium atom, cyano group, nitro group; halogen atom such as fluorine atom, chlorine atom, bromine atom, iodine atom; silyl group such as trimethylsilyl group, triphenylsilyl group; linear or branched alkyl group having 1 to 6 carbon atoms such as methyl group, ethyl group, propyl group; linear or branched alkoxy group having 1 to 6 carbon atoms such as methoxy group, ethoxy group, propoxy group; alkenyl group such as vinyl group, allyl group; aryloxy group such as phenoxy group, tolyloxy group; aralkyloxy group such as benzyloxy group, phenethyloxy group; aromatic hydrocarbon group or condensed polycyclic aromatic group such as phenyl group, biphenyl group, terphenyl group, naphthyl group, anthryl group, phenanthryl group, fluorenyl group, spirobifluorenyl group, indenyl group, pyrenyl group, perylenyl group, fluoranthenyl group, triphenylenyl group; and heteroaromatic group such as pyridyl group, thienyl group, furanyl group, pyrrolyl group, quinolyl group, isoquinolyl group, benzofuranyl group, benzothienyl group, indolyl group, carbazolyl group, benzoxazolyl group, benzothiazolyl group, quinoxalyl group, benzimidazolyl group, pyrazolyl group, dibenzofuranyl group, dibenzothienyl group, carbolinyl group, etc., a group having 6 to 30 carbon atoms as an aromatic group, or a group having 2 to 20 carbon atoms as a heteroaromatic group, etc. can be exemplified, and these substituents can be further substituted with the above-mentioned substituents. In addition, these substituents and the substituted benzene ring or the substituents of the same benzene ring can be bonded to each other via a single bond, a substituted or unsubstituted methylene group, an oxygen atom, or a sulfur atom to form a ring.

[0071] In addition, in the organic EL element of the present application, Ar in General Formula (1) or (1a) is preferably a substituted or unsubstituted aromatic hydrocarbon group, and more preferably a substituted or unsubstituted phenyl group.

[0072] In addition, in the organic EL element of the present application, the thickness of the cap layer is preferably in the range of 30 nm to 120 nm, and more preferably in the range of 40 nm to 80 nm.

[0073] In addition, in the organic EL element of the present application, the refractive index of the cap layer for light having a wavelength within the range of 500 nm to 570 nm which transmits through the cap layer is preferably 1.90 or more, and more preferably 2.00 or more.

[0074] In addition, in the organic EL element of the present application, the cap layer can be produced by laminating two or more different constituent material layers or forming a mixed layer.

[0075] Effects of the Invention

[0076] As for the organic EL element of the present application, by having a capping layer having a higher refractive index than the semi-transparent electrode provided outside the transparent or semi-transparent electrode, an organic EL element capable of greatly improving the light extraction efficiency can be obtained. In addition, capping can be performed. Therefore, damage to the light emitting element does not occur, and a high-precision mask can be used to optimize the light extraction efficiency of each color. In addition, it can be suitably applied to a full-color display, and an image with good color purity, vividness, and brightness can be displayed.

[0077] As for the organic EL element of the present application, a material for an organic EL element having a high light absorption coefficient, a high refractive index, and excellent stability, durability, and light resistance of a thin film is used as the material of the capping layer. Therefore, compared with conventional organic EL elements, the color purity is maintained, and the light extraction efficiency can be greatly improved, without being affected by sunlight. Furthermore, an organic EL element with high efficiency and long life can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0078] Figure 1 FIG. 1 is a diagram showing the structures of compounds (1-1) to (1-12) as amine compounds represented by general formulae (1) and (1a).

[0079] Figure 2 FIG. 2 is a diagram showing the structures of compounds (1-13) to (1-24) as amine compounds represented by general formulae (1) and (1a).

[0080] Figure 3 FIG. 3 is a diagram showing the structures of compounds (1-25) to (1-36) as amine compounds represented by general formulae (1) and (1a).

[0081] Figure 4 FIG. 4 is a diagram showing the structures of compounds (1-37) to (1-48) as amine compounds represented by general formulae (1) and (1a).

[0082] Figure 5 FIG. 5 is a diagram showing the structures of compounds (1-49) to (1-60) as amine compounds represented by general formulae (1) and (1a).

[0083] Figure 6 FIG. 6 is a diagram showing the organic EL element configurations of Examples 12 to 19 and Comparative Examples 1 to 4. DETAILED DESCRIPTION

[0084] The amine compound represented by the above general formula (1) or (1a) of the present embodiment is a novel compound having a benzoxazole ring structure. As for the benzoxazole derivative that is the main skeleton of these compounds, for example, it can be synthesized by a method known per se (for example, refer to Non-Patent Literature 4). Furthermore, the amine compound represented by the above general formula (1) or (1a) of the present embodiment can be synthesized by subjecting a synthesized halogenated benzoxazole derivative to a coupling reaction with an arylamine using a copper catalyst, a palladium catalyst, or the like. In addition, the amine compound represented by the above general formula (1) or (1a) of the present embodiment can also be synthesized by subjecting a halogenated benzoxazole derivative to a coupling reaction with a halogenated arylamine by making the halogenated benzoxazole derivative a boronic acid derivative or a boronic ester derivative (for example, refer to Non-Patent Literatures 5 and 6).

[0085] [Chemical Formula 3]

[0086]

[0087] Among the amine compounds represented by the above general formula (1) or (1a) that are suitable for the organic EL element of the present embodiment, specific examples of the preferable compounds are shown in Table 1. Figures 1-5 However, the compounds are not limited thereto.

[0088] As for the purification of the compound represented by general formula (1) or (1a), purification by column chromatography, adsorption purification using silica gel, activated carbon, activated clay, or the like, recrystallization using a solvent, crystallization, sublimation purification, or the like is performed, and as for the identification of the compound, NMR analysis is performed. As physical property values, the melting point, the glass transition temperature (Tg), and the refractive index are measured. The melting point becomes an index of the evaporation property, the glass transition temperature (Tg) becomes an index of the stability of the thin film state, and the refractive index becomes an index related to the improvement of the light extraction efficiency.

[0089] As for the melting point and the glass transition temperature (Tg), a high-sensitivity differential scanning calorimeter (manufactured by Bruker AXS, DSC3100SA) is used to measure the powder.

[0090] As for the refractive index and the extinction coefficient, a thin film of 80 nm is produced on a silicon substrate, and a spectrometer (manufactured by Filmetrics, F10-RT-UV) is used to measure it.

[0091] As for the absorbance, a toluene solvent is used to adjust the concentration to 10 -5 mol / L. As for the extinction coefficient, a toluene solution is used to adjust the concentration to 5.0 x 10 -6 mol / L, 1.0 x 10 -5 mol / L, 1.5 x 10 -5 mol / L, 2.0 x 10-5 The concentration of each of the four was 0.1 mol / L, and the concentration of each of the four was 0.5 mol / L. The concentrations of the four were measured using a UV-visible near-infrared spectrophotometer (Shimadzu Corporation, V-650).

[0092] As the structure of the organic EL element of the present embodiment, for example, in the case of a light-emitting element of a top emission structure, a multilayer structure composed of, in order, an anode, a hole-transporting layer, a light-emitting layer, an electron-transporting layer, a cathode, and a capping layer on a glass substrate can be exemplified. In addition, a structure having a hole-injecting layer between the anode and the hole-transporting layer of the above multilayer structure, a structure having an electron-blocking layer between the hole-transporting layer and the light-emitting layer of the above multilayer structure, a structure having a hole-blocking layer between the light-emitting layer and the electron-transporting layer of the above multilayer structure, a structure having an electron-injecting layer between the electron-transporting layer and the cathode of the above multilayer structure, and the like can be exemplified. In these multilayer structures, several organic layers can be omitted or combined. For example, it can also be a structure serving as both a hole-injecting layer and a hole-transporting layer, a structure serving as both a hole-transporting layer and an electron-blocking layer, a structure serving as both a hole-blocking layer and an electron-transporting layer, a structure serving as both an electron-transporting layer and an electron-injecting layer, and the like. In addition, it can also be a structure in which two or more organic layers having the same function are stacked. For example, it can also be a structure in which two hole-transporting layers are stacked, a structure in which two light-emitting layers are stacked, a structure in which two electron-transporting layers are stacked, a structure in which two capping layers are stacked, and the like.

[0093] The total of the film thicknesses of the respective layers of the organic EL element is preferably about 200 nm to 750 nm, and more preferably about 350 nm to 600 nm. In addition, the film thickness of the capping layer is preferably, for example, 30 nm to 120 nm, and more preferably 40 nm to 80 nm. In this case, good light extraction efficiency is obtained. Note that the film thickness of the capping layer can be appropriately changed depending on the kind of light-emitting material used in the light-emitting element, the thickness of the organic EL element other than the capping layer, and the like.

[0094] As the anode of the organic EL element of the present embodiment, an electrode material having a large work function such as ITO and gold is used.

[0095] As the hole injection layer of the organic EL element of the present embodiment, an arylamine compound having a structure in which three or more triphenylamine structures are connected by a single bond or a divalent group not containing a hetero atom in a molecule can be used. As such an arylamine compound, for example, starburst-type triphenylamine derivatives, various triphenylamine 4-mer materials, copper phthalocyanine as a representative of a porphyrin compound, a receptor heterocyclic compound such as hexacyanoazatriphenylene, and a coating-type polymer material can be listed. They can be formed into a film alone, but can also be used as a single layer formed by mixing with other materials. In addition, it can be a stacked structure of layers formed alone, layers formed by mixing, or a layer formed alone and a layer formed by mixing.

[0096] As the hole transport layer of the organic EL element of the present embodiment, an arylamine compound having a structure in which two triphenylamine structures are connected by a single bond or a divalent group not containing a hetero atom in a molecule can be used. As such an arylamine compound, for example, N,N'-diphenyl-N,N'-di(a-naphthyl)benzidine (hereinafter referred to as NPD), N,N,N',N'-tetraphenylbenzidine, and the like can be listed. In addition, an arylamine compound having a structure in which three or more triphenylamine structures are connected by a single bond or a divalent group not containing a hetero atom in a molecule is preferably used. As such an arylamine compound, for example, various triphenylamine 3-mer and 4-mer materials can be listed. They can be formed into a film alone, but can also be used as a single layer formed by mixing with other materials. In addition, it can be a stacked structure of layers formed alone, layers formed by mixing, or a layer formed alone and a layer formed by mixing. In addition, as the hole injection and transport layer, a coating-type polymer material such as poly(3,4-ethylenedioxythiophene) (hereinafter referred to as PEDOT) / poly(styrenesulfonic acid) (hereinafter referred to as PSS) can be used. In addition to the evaporation method, these materials can be formed into a film by a publicly known method such as a spin coating method, an inkjet method, and the like.

[0097] In addition, in the hole injection layer or the hole transport layer, a substance obtained by further P-doping of triphenylamine hexachloroantimony, an axeridine derivative (for example, see Patent Document 3), or the like to a material generally used in the layer can be used. In addition, a polymer compound having a structure of a benzidine derivative such as TPD in a partial structure thereof or the like can be used.

[0098] As the electron-blocking layer of the organic EL element of the present embodiment, a carbazole derivative such as 4,4',4"-tris(N-carbazolyl)triphenylamine (hereinafter referred to as TCTA), 9,9-bis[4-(carbazol-9-yl)phenyl]fluorene, 1,3-bis(carbazol-9-yl)benzene (hereinafter referred to as mCP), 2,2-bis(4-carbazol-9-yl-phenyl)adamantane (hereinafter referred to as Ad-Cz), and the like, a compound having a triphenylsilyl group and a triarylamine structure represented by 9-[4-(carbazol-9-yl)phenyl]-9-[4-(triphenylsilyl)phenyl]-9H-fluorene, and the like can be used. These compounds are compounds having an electron-blocking effect. They can be deposited as a single layer, can be used as a single layer deposited by mixing with other materials, and can be a stacked structure of a layer deposited as a single layer and a layer deposited by mixing.

[0099] As the light-emitting layer of the organic EL element of the present embodiment, in addition to a metal complex of a hydroxyquinoline derivative such as Alq3, various metal complexes, anthracene derivatives, distyrylbenzene derivatives, pyrene derivatives, oxazole derivatives, poly-p-phenylenevinylene derivatives, and the like can be used. In addition, the light-emitting layer can be composed of a host material and a dopant material. As the host material, an anthracene derivative is preferably used. In addition to the above-described light-emitting material, a heterocyclic compound having an indole ring as a partial structure of a condensed ring, a heterocyclic compound having a carbazole ring as a partial structure of a condensed ring, a carbazole derivative, a thiazole derivative, a benzimidazole derivative, a polydialkylfluorene derivative, and the like can be used. In addition, as the dopant material, quinacridone, coumarin, rubrene, perylene and derivatives thereof, benzopyran derivatives, rhodamine derivatives, aminostyryl derivatives, and the like can be used, and a green light-emitting material is particularly preferably used. They can be deposited as a single layer, can be used as a single layer deposited by mixing with other materials, and can be a stacked structure of a layer deposited as a single layer and a layer deposited by mixing.

[0100] In addition, a phosphorescent light emitter can also be used as the light emitting material. As the phosphorescent light emitter, a phosphorescent light emitter of a metal complex of iridium, platinum, or the like can be used. A green phosphorescent light emitter such as Ir(ppy)3, a blue phosphorescent light emitter such as FIrpic, FIr6, a red phosphorescent light emitter such as Btp2Ir(acac), or the like is used, and a green phosphorescent light emitter is particularly preferable. As the host material at this time, a carbazole derivative such as 4,4'-bis(N-carbazolyl)biphenyl (hereinafter referred to as CBP), TCTA, mCP, or the like can be used as a host material having a hole injecting and transporting property. As a host material having an electron transporting property, p-bis(triphenylsilyl)benzene (hereinafter referred to as UGH2), 2,2',2"-(l,3,5-phenyl ene)-tris(l-phenyl-lH-benzimidazole) (hereinafter referred to as TPBI), or the like can be used. If such a host material is used, an organic EL element having a high performance can be produced.

[0101] In the case of doping of a phosphorescent light emitting material into a host material, in order to avoid concentration quenching, doping is preferably performed by co-evaporation in a range of 1 to 30% by weight with respect to the entire light emitting layer.

[0102] In addition, as the light emitting material, a material emitting delayed fluorescence such as a CDCB derivative such as PIC-TRZ, CC2TA, PXZ-TRZ, 4CzIPN, or the like can also be used. (For example, see Non-Patent Document 7) In addition to the evaporation method, these materials can be formed into a thin film by a publicly known method such as a spin coating method, an inkjet method, or the like.

[0103] As the hole blocking layer of the organic EL element of the present embodiment, a phenanthroline derivative such as bathocuproin (hereinafter omitted as BCP), a metal complex of a hydroxyquinoline derivative such as bis(2-methyl-8-quinolino)4-phenylphenol aluminum (III) (hereinafter omitted as BAlq), various rare earth complexes, a triazole derivative, a triazine derivative, a pyrimidine derivative, an oxadiazole derivative, a benzoxazole derivative, or the like can be used. These compounds have a hole blocking action. These materials can also serve as a material of an electron transporting layer. They can be formed into a film alone, but can also be used as a single layer formed by mixing with other materials, and can be a stacked structure of layers formed by mixing layers formed alone with each other or layers formed by mixing with each other. In addition to the evaporation method, these materials can be formed into a thin film by a publicly known method such as a spin coating method, an inkjet method, or the like.

[0104] As the electron transport layer of the organic EL element of the present embodiment, various metal complexes, triazole derivatives, triazine derivatives, pyrimidine derivatives, oxadiazole derivatives, pyridine derivatives, benzimidazole derivatives, benzoxazole derivatives, thiadiazole derivatives, anthracene derivatives, carbodiimide derivatives, quinoxaline derivatives, pyridoindole derivatives, phenanthroline derivatives, thioxyl derivatives, and the like can be used in addition to metal complexes of hydroxyquinoline derivatives such as Alq3, BAIq. They can be formed into a single layer alone or in mixture with other materials, and can be in a stacked structure of layers formed alone, layers formed in mixture, or layers formed alone and layers formed in mixture.

[0105] As the electron injection layer of the organic EL element of the present embodiment, alkali metal salts such as lithium fluoride, cesium fluoride; alkaline earth metal salts such as magnesium fluoride; metal complexes of hydroxyquinoline derivatives such as lithium hydroxyquinolinate; metal oxides such as aluminum oxide; or metals such as ytterbium (Yb), samarium (Sm), calcium (Ca), strontium (Sr), cesium (Cs), and the like can be used. In the preferred selection of the electron transport layer and the cathode, it can be omitted.

[0106] Further, in the electron injection layer or the electron transport layer, a substance obtained by further N-doping a metal such as cesium to a material generally used in the layer can be used.

[0107] As the cathode of the organic EL element of the present embodiment, an electrode material having a low work function such as aluminum; an alloy having a lower work function such as a magnesium-silver alloy, a magnesium-calcium alloy, a magnesium-indium alloy, an aluminum-magnesium alloy; ITO; IZO; and the like are used as the electrode material.

[0108] As the capping layer of the organic EL element of the present embodiment, an amine compound represented by the above general formula (1) or (1a) and the like are preferably used. They can be formed into a single layer alone or in mixture with other materials, and can be in a stacked structure of layers formed alone, layers formed in mixture, or layers formed alone and layers formed in mixture. In addition to the evaporation method, these materials can be formed into a thin film by a publicly known method such as a spin coating method, an inkjet method, and the like.

[0109] Note that, in the above, the organic EL element of the top emission structure is described, but the present embodiment is not limited thereto, and the same can be applied to an organic EL element of a bottom emission structure, and an organic EL element of a double emission structure that emits light from both the upper and lower sides. In these cases, the electrode located in the direction in which light is taken out from the light emitting element to the outside needs to be transparent or semi-transparent.

[0110] The refractive index of the material constituting the capping layer is preferably greater than that of the adjacent electrodes. That is, the light extraction efficiency in the organic EL element is improved through the capping layer; however, for optimal light interference, a higher reflectivity at the interface between the capping layer and the material in contact with it is more effective. Therefore, the refractive index of the material constituting the capping layer is preferably greater than that of the adjacent electrodes; a refractive index of 1.90 or higher is acceptable, but 2.00 or higher is more preferable.

[0111] As an example of the method for manufacturing the organic EL element in this embodiment, for example, such as Figure 6 As shown, a method for manufacturing a metal anode 2 by pre-forming a reflective ITO electrode as a metal anode on a glass substrate 1, and then sequentially depositing a hole injection layer 3, a first hole transport layer 4, a second hole transport layer 5, a light-emitting layer 6, an electron transport layer 7, an electron injection layer 8, a cathode 9, and a capping layer 10 thereon. The capping layer 10 contains an amine compound represented by the above general formula (1) or formula (1a).

[0112] The embodiments of the present invention will be specifically described below, but the present invention is not limited to the following embodiments as long as it does not depart from its spirit.

[0113] Example

[0114] [Example 1]

[0115] <Synthesis of Exemplary Compound (1-18)>

[0116] Add 7.0 g of 4-(3-dibenzofuranyl)aniline, 16.3 g of 2-(4-bromophenyl)benzoxazole, 7.8 g of sodium tert-butoxide, and 70 ml of toluene to the reaction vessel, and purge with nitrogen for 30 minutes. Add 0.7 g of tris(dibenzylacetone)dipalladium(O) and 0.7 g of a 50% (w / v) toluene solution of tris-(tert-butyl)phosphine, and stir under reflux overnight.

[0117] After natural cooling, dispersion washing was performed at 80°C, and the insoluble matter was filtered off. The filtrate was concentrated to obtain the crude product. The solid precipitated from the crude product by crystallization with toluene solvent was collected to obtain 12.3 g of yellow powder of the illustrative compound (1-18) (yield 70.6%).

[0118] [Chemistry 4]

[0119]

[0120] The structure of the obtained yellow powder was identified using NMR.

[0121] use 1 H-NMR (CDCl3) detected the following 27 hydrogen signals.

[0122] δ (ppm) = 8.23-8.20 (4H), 8.05-7.99 (2H), 7.84-7.50 (10H), 7.41-7.32 (11H).

[0123] [Example 2]

[0124] <Synthesis of Exemplified Compound (1-6)>

[0125] Into a reaction vessel were placed 4-(3-dibenzofuranyl)aniline: 6.1 g, 2-(4-bromophenyl)benzothiazole: 15.0 g, sodium t-butoxide: 6.8 g, toluene: 60 ml, and nitrogen was bubbled for 30 minutes. Tris(dibenzylideneacetone)dipalladium(0): 0.7 g, 50% (w / v) toluene solution of tri-(t-butyl)phosphine: 0.6 g, and stirred under heating reflux for one night.

[0126] After natural cooling, dispersion washing was carried out at 80°C, insolubles were filtered, and the filtrate was concentrated to obtain a crude product. The crude product was refined by crystallization using toluene solvent to precipitate a solid, and yellow powder of Exemplified Compound (1-6): 9.1 g (yield 57.1%) was obtained.

[0127] [Formula 5]

[0128]

[0129] For the obtained yellow powder, NMR was used to identify the structure.

[0130] Using 1 H-NMR (CDC13) detected the following 27 hydrogen signals.

[0131] δ (ppm) = 8.23-8.20 (4H), 8.05-7.99 (2H), 7.84-7.50 (10H), 7.41-7.32 (11H).

[0132] [Example 3]

[0133] <Synthesis of Exemplified Compound (1-17)>

[0134] Into a reaction vessel were placed 4-(4-dibenzofuranyl)aniline: 5.3 g, 2-(4-bromophenyl)benzoxazole: 12.3 g, sodium t-butoxide: 5.9 g, toluene: 50 ml, and nitrogen was bubbled for 30 minutes. Tris(dibenzylideneacetone)dipalladium(0): 0.6 g, 50% (w / v) toluene solution of tri-(t-butyl)phosphine: 0.5 g, and stirred under heating reflux for one night.

[0135] After natural cooling, dispersion washing was performed at 80°C, insolubles were filtered, the filtrate was concentrated to obtain a crude product. The solid which was refined by crystallization refinement using toluene solvent from the crude product was collected to obtain a yellow powder of the Exemplified Compound (1-17): 6.8 g (yield 51.5%).

[0136] [Chemical 6]

[0137]

[0138] The structure was identified using NMR for the obtained yellow powder.

[0139] Using 1 The signals of the following 27 hydrogens were detected by1H-NMR (CDCI3).

[0140] δ (ppm) = 8.24-8.20 (4H), 8.05-7.96 (4H), 7.80-7.77 (2H), 7.68-7.59 (4H), 7.51-7.36 (13H).

[0141] [Example 4]

[0142] > Synthesis of Exemplified Compound (1-5)

[0143] To a reaction vessel were added 4-(4-dibenzofuranyl)aniline: 5.3 g, 2-(4-bromophenyl)benzothiazole: 13.1 g, sodium tert-butoxide: 5.9 g, toluene: 100 ml, and nitrogen was bubbled for 30 minutes. Tris(dibenzylideneacetone)dipalladium(0): 0.6 g, 50% (w / v) toluene solution of tri-(tert-butyl)phosphine: 0.5 g, and stirring was performed under heating reflux for one night.

[0144] After natural cooling, dispersion washing was performed at 80°C, insolubles were filtered, the filtrate was concentrated to obtain a crude product. The solid which was refined by crystallization refinement using toluene solvent from the crude product was collected to obtain a yellow powder of the Exemplified Compound (1-5): 7.5 g (yield 54.15%).

[0145] [Chemical 7]

[0146]

[0147] The structure was identified using NMR for the obtained yellow powder.

[0148] Using 1 The signals of the following 27 hydrogens were detected by1H-NMR (CDCI3).

[0149] δ (ppm) = 8.10-7.91 (12H), 7.68-7.64 (2H), 7.54-7.33 (13H).

[0150] [Example 5]

[0151] <Synthesis of Exemplary Compound (1-19)>

[0152] Add 7.0 g of 4-(2-dibenzofuranyl)aniline, 16.3 g of 2-(4-bromophenyl)benzoxazole, 7.8 g of sodium tert-butoxide, and 70 ml of toluene to the reaction vessel, and purge with nitrogen for 30 minutes. Add 0.7 g of tris(dibenzylacetone)dipalladium(O) and 0.7 g of a 50% (w / v) toluene solution of tris-(tert-butyl)phosphine, and stir under reflux overnight.

[0153] After natural cooling, dispersion washing was performed at 80°C, and the insoluble matter was filtered out. The filtrate was concentrated to obtain the crude product. The solid precipitated from the crude product by crystallization with toluene solvent was collected to obtain a yellow powder of the illustrative compound (1-19): 9.9 g (yield 56.9%).

[0154] [Chemistry 8]

[0155]

[0156] The structure of the obtained yellow powder was identified using NMR.

[0157] use 1 H-NMR (CDCl3) detected the following 27 hydrogen signals.

[0158] δ(ppm)=8.24-8.19(5H), 8.05-8.02(1H), 7.80-7.58(9H), 7.54-7.49(1H), 7.43-7.32(11H).

[0159] [Example 6]

[0160] <Synthesis of Exemplary Compound (1-7)>

[0161] Add 5.0 g of 4-(2-dibenzofuranyl)aniline, 12.3 g of 2-(4-bromophenyl)benzothiazole, 5.6 g of sodium tert-butoxide, and 50 ml of toluene to the reaction vessel, and purge with nitrogen for 30 minutes. Add 0.5 g of tris(dibenzylacetone)dipalladium(O) and 0.5 g of a 50% (w / v) toluene solution of tris-(tert-butyl)phosphine, and stir under reflux overnight.

[0162] After natural cooling, dispersion washing was performed at 80°C, insoluble matter was filtered out, and the filtrate was concentrated to obtain crude product. The solid precipitated from the crude product by crystallization with monochlorobenzene solvent was collected to obtain 8.5 g of yellow powder of the illustrative compounds (1-7) (yield 65.0%).

[0163] [Chemical 9]

[0164]

[0165] The structure of the obtained yellow powder was identified using NMR.

[0166] Using 1 The following 27 hydrogen signals were detected by H-NMR (CDC13).

[0167] δ (ppm) = 8.20-8.19 (1H), 8.09-8.03 (6H), 7.94-7.91 (2H), 7.75-7.61 (5H), 7.54-7.49 (3H), 7.43-7.30 (10H).

[0168] [Example 7]

[0169] Synthesis of Exemplified Compound (1-13)

[0170] Into a reaction vessel were placed 4-(4-dibenzothienyl)aniline: 5.0 g, 2-(4-bromophenyl)benzoxazole: 11.0 g, sodium tert-butoxide: 5.2 g, toluene: 50 ml, and nitrogen was bubbled for 30 minutes. Tris(dibenzylideneacetone)dipalladium(0): 0.5 g, 50% (w / v) toluene solution of tri-(tert-butyl)phosphine: 0.4 g, and stirring was carried out under heating reflux for one night.

[0171] After natural cooling, dispersion washing was carried out at 80°C, insolubles were filtered, the filtrate was concentrated, and a crude product was obtained. The crude product was refined by crystallization using toluene solvent, and the solid refined by crystallization was collected, and yellow powder of Exemplified Compound (1-13) was obtained: 10.6 g (yield 88.2%).

[0172] [Chemical 10]

[0173]

[0174] The structure of the obtained yellow powder was identified using NMR.

[0175] Using 1 The following 27 hydrogen signals were detected by H-NMR (CDC13).

[0176] δ (ppm) = 8.25-8.18 (6H), 7.91-7.88 (1H), 7.81-7.78 (4H), 7.63-7.49 (6H), 7.41-7.34 (10H).

[0177] [Example 8]

[0178] Synthesis of Exemplified Compound (1-1)

[0179] Into a reaction vessel, 4-(4-dibenzothienyl)aniline: 5.0 g, 2-(4-bromophenyl)benzothiazole: 11.6 g, sodium t-butoxide: 5.2 g, toluene: 50 ml were charged, and nitrogen was bubbled for 30 minutes. Tris(dibenzylideneacetone)dipalladium(0): 0.5 g, 50% (w / v) toluene solution of tri-(t-butyl)phosphine: 0.4 g were added, and stirring was carried out under heating reflux for one night.

[0180] After natural cooling, dispersion washing was carried out at 80°C, insolubles were filtered, the filtrate was concentrated, and a crude product was obtained. The crude product was refined by crystallization using monochlorobenzene solvent, and the solid refined and separated was collected, and yellow powder of Exemplified Compound (1-1): 9.1 g (yield 72.22%) was obtained.

[0181] [Chemical 11]

[0182]

[0183] For the obtained yellow powder, NMR was used to identify the structure.

[0184] Using 1 H-NMR (CDC13) detected the following 27 hydrogen signals.

[0185] δ (ppm) = 8.24-8.18 (2H), 8.10-8.06 (6H), 7.94-7.88 (3H), 7.79-7.76 (2H), 7.63-7.49 (6H), 7.43-7.33 (8H).

[0186] [Example 9]

[0187] For the amine compounds represented by general formula (1) or (1a), the melting point and glass transition temperature measured using a high sensitivity differential scanning calorimeter (manufactured by BURKER AXE S, DSC3100SA) were adopted.

[0188]

[0189] The amine compounds represented by general formula (1) or (1a) have a glass transition temperature of 100°C or higher, and show that the thin film state is stable.

[0190] [Example 10]

[0191] An evaporation film having a film thickness of 80 nm was produced on a silicon substrate using the amine compound represented by General Formula (1) or (1a). For the produced sample, the refractive index n at wavelengths of 400 nm, 410 nm, 500 nm, 570 nm and the extinction coefficient k at wavelengths of 400 nm, 410 nm were measured using a spectrophotometer (manufactured by Filmetrics, Inc., F10-RT-UV). For comparison, the following Comparative Compounds (2-1), (2-2), (2-3), and (2-4) were also measured (for example, refer to Patent Literature 4). The measurement results are shown in Table 1.

[0192] [Chem. 12]

[0193]

[0194] [Chem. 13]

[0195]

[0196] [Chem. 14]

[0197]

[0198] [Chem. 15]

[0199]

[0200] [Table 1]

[0201]

[0202] Thus, the compound of the present application has a refractive index of 1.90 or more at wavelengths of 500 nm to 570 nm, and has a value equivalent to or more than that of the comparative compound, which can be expected to improve the light extraction efficiency in an organic EL element. In addition, with respect to the extinction coefficient at wavelengths of 400 nm to 410 nm, the comparative compound is 0.03 to 0.45, and in contrast, the compound of the present application has 0.53 to 1.08. This shows that light at wavelengths of 400 nm to 410 nm, which is a wavelength of sunlight, is sufficiently absorbed without affecting the materials inside the element.

[0203] [Example 11]

[0204] With respect to absorbance, the absorbance at wavelengths of 400 nm, 410 nm was measured using the compound of the present application, using a toluene solution adjusted to a concentration of 10 -5 mol / L. -6 With respect to the extinction coefficient, the concentration was adjusted to 5 x 10 -5 mol / L, 1 x 10 -5 mol / L, 2.0 x 10-5 The absorbance was measured using a UV-VIS-NIR spectrophotometer (Shimadzu Corporation, V-650) at four concentrations of 0.01, 0.1, 1.0, and 10.0 mol / L, and the absorbance coefficient was calculated from a standard curve. For comparison, the comparative compounds (2-1), (2-2), (2-3), and (2-4) of the above structural formula were also measured. The results are shown in Table 2.

[0205] [Table 2]

[0206]

[0207] Thus, in terms of the absorbance at a wavelength of 400 nm, the comparative compounds were 0.02 to 0.60, and in contrast, the compounds of the present application were 0.74 to 1.38. The compounds of the present application had large values. In terms of the absorbance at 410 nm, the comparative compounds were 0.00 to 0.21, and in contrast, the compounds of the present application were 0.27 to 1.18. The compounds of the present application had large values. This shows that the compounds of the present application sufficiently absorb light at a wavelength of 400 nm to 410 nm of sunlight, and in addition, in terms of the absorbance coefficient, the compounds of the present application had values of 100000 or more. That is, it was shown that the compounds of the present application sufficiently absorb light if under the same concentration conditions. In addition, it was shown that, in terms of the compounds of the present application, in terms of the thin film, the thicker the film, the more sufficient the light absorption, and it is a material excellent in light resistance.

[0208] [Example 12]

[0209] In terms of the organic EL element, as shown in Figure 6 , a reflective ITO electrode was formed in advance on a glass substrate 1 as a metal anode 2, and a hole injection layer 3, a first hole transport layer 4, a second hole transport layer 5, a light emitting layer 6, an electron transport layer 7, an electron injection layer 8, a cathode 9, and a capping layer 10 were sequentially vapor-deposited thereon to produce.

[0210] Specifically, after a glass substrate 1 on which ITO of 50 nm in thickness, a reflective film of silver alloy of 100 nm in thickness, and ITO of 5 nm in thickness were sequentially formed was subjected to ultrasonic cleaning in isopropanol for 20 minutes, drying was performed on a hot plate heated to 250°C for 10 minutes. Thereafter, after UV ozone treatment was performed for 2 minutes, the ITO-equipped glass substrate was installed in a vacuum deposition machine, and the pressure was reduced to 0.001 Pa or less. Next, as a hole injection layer 3, an electron acceptor of the following structural formula (Acceptor-1) and a compound (3-1) of the following structural formula were subjected to binary deposition at a deposition rate ratio of Acceptor-1 : compound (3-1) = 3 : 97 in a manner so as to cover the metal anode 2, and were formed in a manner so as to have a film thickness of 10 nm. On the hole injection layer 3, as a first hole transport layer 4, the compound (3-1) of the following structural formula was formed in a manner so as to have a film thickness of 70 nm. On the first hole transport layer 4, as a second hole transport layer 5, the compound (3-2) of the following structural formula was formed in a manner so as to have a film thickness of 10 nm. On the second hole transport layer 5, as a light-emitting layer 6, the compound (3-3) of the following structural formula and the compound (3-4) of the following structural formula were subjected to binary deposition at a deposition rate ratio of (3-3) : (3-4) = 5 : 95, and were formed in a manner so as to have a film thickness of 40 nm. On the light-emitting layer 6, as an electron transport layer 7, the compound (3-5) of the following structural formula and the compound (3-6) of the following structural formula were subjected to binary deposition at a deposition rate ratio of (3-5) : (3-6) = 50 : 50, and were formed in a manner so as to have a film thickness of 30 nm. On the electron transport layer 7, as an electron injection layer 8, lithium fluoride was formed in a manner so as to have a film thickness of 1 nm.

[0211] On the electron injection layer 8, as a cathode 9, a magnesium-silver alloy was formed in a manner so as to have a film thickness of 12 nm. Finally, as a capping layer 10, the compound (1-18) of Example 1 was formed in a manner so as to have a film thickness of 60 nm. The produced organic EL element was subjected to property measurement in the atmosphere at ordinary temperature.

[0212] The results of measurement of the light-emitting properties of the produced organic EL element to which a direct current voltage was applied are shown in Table 3.

[0213] [Chem. 16]

[0214]

[0215] [Chem. 17]

[0216]

[0217] [Chem. 18]

[0218]

[0219] [Chem. 19]

[0220]

[0221] [Chem. 20]

[0222]

[0223] [Chem. 21]

[0224]

[0225] [Chem. 22]

[0226]

[0227] [Chem. 23]

[0228]

[0229] [Example 13]

[0230] An organic EL element was produced under the same conditions except that, in Example 12, the compound (1-6) of Example 2 was used instead of the compound (1-18) of Example 1 as the material of the capping layer 10. The produced organic EL element was subjected to property measurement in the atmosphere at normal temperature. The results of measurement of the emission property when a direct current voltage was applied to the produced organic EL element are shown in Table 3.

[0231] [Chem. 24]

[0232]

[0233] [Example 14]

[0234] An organic EL element was produced under the same conditions except that, in Example 12, the compound (1-17) of Example 3 was used instead of the compound (1-18) of Example 1 as the material of the capping layer 10. The produced organic EL element was subjected to property measurement in the atmosphere at normal temperature. The results of measurement of the emission property when a direct current voltage was applied to the produced organic EL element are shown in Table 3.

[0235] [Chem. 25]

[0236]

[0237] [Example 15]

[0238] Except that in Example 12, compounds (1-5) of Example 4 were used instead of compounds (1-18) of Example 1 as the material for the capping layer 10, the organic EL element was manufactured under the same conditions. The characteristics of the manufactured organic EL element were measured in atmospheric air at room temperature. The results of the measurement of the luminescence characteristics of the manufactured organic EL element when a DC voltage was applied are summarized in Table 3.

[0239] [Chemistry 26]

[0240]

[0241] [Example 16]

[0242] Except that in Example 12, compounds (1-19) of Example 5 were used instead of compounds (1-18) of Example 1 as the material for the capping layer 10, the organic EL element was manufactured under the same conditions. The characteristics of the manufactured organic EL element were measured in atmospheric air at room temperature. The results of the measurement of the luminescence characteristics of the manufactured organic EL element when a DC voltage was applied are summarized in Table 3.

[0243] [Chemistry 27]

[0244]

[0245] [Example 17]

[0246] Except that in Example 12, compounds (1-7) of Example 6 were used instead of compounds (1-18) of Example 1 as the material for the capping layer 10, the organic EL element was manufactured under the same conditions. The characteristics of the manufactured organic EL element were measured in atmospheric air at room temperature. The results of the measurement of the luminescence characteristics of the manufactured organic EL element when a DC voltage was applied are summarized in Table 3.

[0247] [Chemistry 28]

[0248]

[0249] [Example 18]

[0250] Except that in Example 12, compounds (1-13) of Example 7 were used instead of compounds (1-18) of Example 1 as the material for the capping layer 10, the organic EL element was manufactured under the same conditions. The characteristics of the manufactured organic EL element were measured in atmospheric air at room temperature. The results of the measurement of the luminescence characteristics of the manufactured organic EL element when a DC voltage was applied are summarized in Table 3.

[0251] [Chemistry 29]

[0252]

[0253] [Example 19]

[0254] An organic EL element was produced under the same conditions except that the compound (1-1) of Example 8 was used instead of the compound (1-18) of Example 1 as the material of the capping layer 10 in Example 12. The luminescent properties of the produced organic EL element when a direct current voltage was applied thereto were measured in the atmosphere at normal temperature. The measurement results of the luminescent properties of the produced organic EL element are shown in Table 3.

[0255] [Compound 30]

[0256]

[0257] [Comparative Example 1]

[0258] For comparison, an organic EL element was produced under the same conditions except that the comparative compound (2-1) of the following structural formula was formed so as to have a film thickness of 60 nm instead of the compound (1-18) of Example 1 as the material of the capping layer 10 in Example 7. The luminescent properties of the produced organic EL element when a direct current voltage was applied thereto were measured in the atmosphere at normal temperature. The measurement results of the luminescent properties of the produced organic EL element are shown in Table 3.

[0259] [Compound 31]

[0260]

[0261] [Comparative Example 2]

[0262] For comparison, an organic EL element was produced under the same conditions except that the comparative compound (2-2) of the following structural formula was formed so as to have a film thickness of 60 nm instead of the compound (1-18) of Example 1 as the material of the capping layer 10 in Example 7. The luminescent properties of the produced organic EL element when a direct current voltage was applied thereto were measured in the atmosphere at normal temperature. The measurement results of the luminescent properties of the produced organic EL element are shown in Table 3.

[0263] [Compound 32]

[0264]

[0265] [Comparative Example 3]

[0266] For comparison, under the same conditions, an organic EL element was produced except that, in Example 7, Comparative Compound (2-3) of the following structural formula was formed as the cap layer 10 at a film thickness of 60 nm instead of Compound (1-18) of Example 1. The produced organic EL element was subjected to property measurement at normal temperature in the atmosphere. The measurement results of the light emission properties of the produced organic EL element obtained by applying a direct current voltage thereto are shown in Table 3.

[0267] [Chem. 33]

[0268]

[0269] [Comparative Example 4]

[0270] For comparison, under the same conditions, an organic EL element was produced except that, in Example 7, Comparative Compound (2-4) of the following structural formula was formed as the cap layer 10 at a film thickness of 60 nm instead of Compound (1-18) of Example 1. The produced organic EL element was subjected to property measurement at normal temperature in the atmosphere. The measurement results of the light emission properties of the produced organic EL element obtained by applying a direct current voltage thereto are shown in Table 3.

[0271] [Chem. 34]

[0272]

[0273] The results of measurement of the element life obtained by using the organic EL elements produced in Examples 12 to 19 and Comparative Examples 1 to 4 are shown in Table 3. The element life was measured as the time until the initial luminance was attenuated to 95% when the constant current driving was performed at 10 mA / cm 2 .

[0274] [Table 3]

[0275]

[0276] As shown in Table 3, in terms of the driving voltage at a current density of 10 mA / cm 2 , the elements of Comparative Examples 1 to 4 using the comparative compounds and the elements of Examples 12 to 19 of the present application were substantially the same, and, in contrast, in terms of the luminance, the light emission efficiency, the power efficiency, and the life, the elements of Examples 12 to 19 of the present application were significantly improved relative to the elements of Comparative Examples 1 to 4 using the comparative compounds. This shows that, by including a material having a high refractive index, which is suitable for use in the organic EL element of the present application, in the cap layer, the light extraction efficiency can be greatly improved.

[0277] Industrial Applicability

[0278] As described above, the amine compound represented by General Formula (1) which is suitable for the organic EL element of the present application has a high light absorption coefficient, a high refractive index, can greatly improve the light extraction efficiency, and is stable in a thin film state, and thus is excellent as a compound for an organic EL element. By using this compound to produce an organic EL element, high efficiency can be obtained, and at the same time, durability and light resistance can be improved in a manner that absorbs sunlight without affecting the materials inside the element. In addition, by using this compound which does not have absorption in the respective wavelength regions of blue, green, and red, it is particularly suitable in cases where it is desired to display an image that is good in color purity, clear, and bright. For example, it can be gradually developed for use in household electric appliances, lighting, and the like.

[0279] BRIEF DESCRIPTION OF DRAWINGS

[0280] 1 glass substrate

[0281] 2 metal anode

[0282] 3 hole injection layer

[0283] 4 first hole transport layer

[0284] 5 second hole transport layer

[0285] 6 light emitting layer

[0286] 7 electron transport layer

[0287] 8 electron injection layer

[0288] 9 cathode

[0289] 10 sealing layer

Claims

1. An organic electroluminescent element which is an organic electroluminescent element having, in the stated order, an anode, a hole-transporting layer, a light-emitting layer, an electron-transporting layer, a cathode, and a capping layer, characterized in that the refractive index of the material of the capping layer is 1.90 or greater at a wavelength of 500 nm to 570 nm, the capping layer comprises at least one selected from the group consisting of a compound (1-18) represented by the following formula (1-18) and a compound (1-6) represented by the following formula (1-6), the hole-transporting layer comprises an arylamine compound having a structure in which 2 triphenylamine structures are linked by a 2-valent group that is a single bond or does not contain a hetero atom in a molecule, 2. The organic electroluminescent element according to claim 1, wherein the thickness of the capping layer is in the range of 30 nm to 120 nm.

3. A method for manufacturing the organic electroluminescent element according to claim 1 or 2.

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