Phenanthroline compound and organic electroluminescent device

Abstract

In the present invention, a phenanthroline compound represented by general formula (A) has a high refractive index to wavelengths of 450 nm to 750 nm and a low extinction coefficient, and therefore is useful as a material for a capping layer of an organic EL device. Ar represents an unsubstituted heteroaryl group; L1 and L2 represent a single bond, an arylene group, or a heteroarylene group; X represents a methylene group, an oxygen atom, or a sulfur atom; and A represents an unsubstituted phenanthrolinyl group.

Description

Phenanthroline compounds and organic electroluminescent devices

[0001] The present invention relates to a compound suitable for a self-luminous electronic element suitable for various display devices, particularly a phenanthroline compound suitable for an organic electroluminescent element (hereinafter abbreviated as organic EL element), and to an organic EL element, an electronic element and an electronic device using the compound.

[0002] Organic EL elements are self-luminous elements, and therefore are brighter and more visible than liquid crystal elements, and are capable of producing clearer displays, and therefore have been the subject of vigorous research.

[0003] In 1987, C. W. Tang et al. of Eastman Kodak Company made organic EL devices practical by developing a layered structure element in which various roles are assigned to each material. They layered a phosphor capable of transporting electrons and an organic material capable of transporting holes, and by injecting both charges into the phosphor layer to emit light, they achieved 1000 cd / m at a voltage of 10 V or less. ２ Such high brightness is achieved (see, for example, Patent Documents 1 and 2).

[0004] To date, many improvements have been made to the practical application of organic EL elements, and the role of each layer in the laminated structure has been further subdivided. 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 to form a light-emitting element with a bottom emission structure that emits light from the bottom, thereby achieving high efficiency and durability (see, for example, Non-Patent Document 1).

[0005] In recent years, light-emitting devices with a top-emission structure that uses a metal with a high work function as the anode and emits light from the top have come into use. In a bottom-emission structure in which light is extracted from the bottom where the pixel circuit is located, the area of ​​the light-emitting section is limited, whereas a light-emitting device with a top-emission structure has the advantage that the light is extracted from the top and is not blocked by the pixel circuit, allowing for a larger light-emitting section. In light-emitting devices with a top-emission structure, a semi-transparent electrode such as LiF / Al / Ag (see, for example, Non-Patent Document 2), Ca / Mg (see, for example, Non-Patent Document 3), or LiF / MgAg is used as the cathode.

[0006] In such light-emitting devices, when light emitted from the light-emitting layer is incident on another film at an angle greater than a certain value, it is totally reflected at the interface between the light-emitting layer and the other film. As a result, only a portion of the emitted light can be utilized. In recent years, in order to improve the light extraction efficiency, light-emitting devices have been proposed in which a "capping layer" with a high refractive index is provided on the outside of a semi-transparent electrode with a low refractive index (see, for example, Non-Patent Documents 2 and 3).

[0007] As an effect of the capping layer in a top-emission light-emitting device, Ir(ppy) ３ In a light-emitting device using ZnSe as the light-emitting material, the current efficiency was 38 cd / A when there was no capping layer, whereas in a light-emitting device using ZnSe with a thickness of 60 nm as the capping layer, the efficiency was improved by approximately 1.7 times to 64 cd / A. Furthermore, it has been shown that the maximum points of the transmittance of the semi-transparent electrode and the capping layer do not necessarily coincide with the maximum points of the efficiency, and that the maximum point of the light extraction efficiency is determined by the interference effect (see, for example, Non-Patent Document 3).

[0008] Conventionally, the use of a high-resolution metal mask has been proposed for forming a capping layer, but when used under high-temperature conditions, the metal mask can become distorted due to heat, resulting in a problem of reduced alignment accuracy. Therefore, ZnSe, which has a high melting point of 1100°C or higher, cannot be deposited in the correct position using a high-resolution metal mask, which may adversely affect the light-emitting element (see, for example, Non-Patent Document 3). Furthermore, even when deposited by sputtering, the capping layer, which is made of an inorganic material, is not suitable for use, since it adversely affects the light-emitting element.

[0009] In addition, tris(8-hydroxyquinoline)aluminum (hereinafter referred to as Alq) is used as a capping layer for adjusting the refractive index. ３ It has also been proposed to use Alq ３ is known as an organic EL material that is generally used as a green light-emitting material or an electron transport material, and has weak absorption around 450 nm, which is close to the emission wavelength of blue light-emitting materials. Therefore, in the case of blue light-emitting devices, there are problems such as a decrease in color purity and a decrease in light extraction efficiency.

[0010] US5792557US5639914International Publication No. 2014 / 009310US2014 / 0225100 A1

[0011] Proceedings of the 9th Seminar of the Japan Society of Applied Physics, pages 55-61 (2001) Appl. Phys. Let. , 78, 544 (2001) Appl. Phys. Let. , 82, 466 (2003) Tetrahedron, 58, 9633 (2002) Appl. Phys. Let. , 98, 083302 (2011)

[0012] As described above, the use of an organic capping layer that exhibits a high refractive index in the emission wavelength range of the element is effective for improving the light extraction efficiency of an organic EL element. However, the organic capping materials proposed so far do not have a sufficiently high refractive index in the emission wavelength range of the organic EL element, and therefore are unable to sufficiently improve the efficiency of the element.

[0013] Therefore, in order to solve the problems of the conventional technology, the present inventors have conducted extensive research with the aim of providing an organic compound having a high refractive index and a low extinction coefficient for light with wavelengths of 450 nm to 750 nm, and further with the aim of providing an organic EL device with high efficiency.

[0014] As a result of extensive research to achieve the above-mentioned object, the present inventors have found that phenanthroline compounds have excellent stability and durability in a thin film state, and that by adding a specific aromatic ring group or aromatic heterocyclic group to the phenanthroline compound, a material can be obtained that has a high refractive index in the wavelength range of 450 nm to 750 nm and a low extinction coefficient. They have also found that using such a phenanthroline compound as a material for a capping layer can realize an organic EL device that has high luminous efficiency and a long lifetime. The present invention has been proposed based on these findings and specifically has the following configuration.

[0015] 1) A phenanthroline compound represented by the following general formula (A):

[0016]

[0017] In the formula, Ar represents an unsubstituted heteroaryl group; １ and L ２ each independently represents a single bond, an arylene group, or a heteroarylene group, and at least one hydrogen atom of the arylene group and the heteroarylene group may be substituted with an atom or group selected from the group consisting of a deuterium atom, a cyano group, a nitro group, a halogen atom, a silyl group, an alkyl group, an alkyloxy group, an alkenyl group, an aryloxy group, an arylalkyloxy group, an aryl group, and a heteroaryl group. X represents a methylene group, an oxygen atom, or a sulfur atom, and at least one hydrogen atom of the methylene group may be substituted with an atom or group selected from the group consisting of a deuterium atom, a cyano group, a nitro group, a halogen atom, a silyl group, an alkyl group, an alkyloxy group, an alkenyl group, an aryloxy group, an arylalkyloxy group, an aryl group, and a heteroaryl group. A represents an unsubstituted phenanthrolinyl group.

[0018] 2) The phenanthroline compound according to 1), wherein A in the general formula (A) is an unsubstituted 1,10-phenanthrolinyl group. This results in a 1,10-phenanthroline compound.

[0019] 3) The phenanthroline compound according to 2), wherein the general formula (A) is the following general formula (B):

[0020]

[0021] In general formula (B), A represents an unsubstituted 1,10-phenanthrolinyl group. １ , L ２ and X is as defined in the general formula (A) above.

[0022] 4) The phenanthroline compound according to 3), wherein X in general formula (B) is a methylene group, and at least one hydrogen atom of the methylene group is optionally substituted with an atom or group selected from the group consisting of a deuterium atom, a cyano group, a nitro group, a halogen atom, a silyl group, an alkyl group, an alkyloxy group, an alkenyl group, an aryloxy group, an arylalkyloxy group, an aryl group, and a heteroaryl group.

[0023] 5) L in the general formula (B) １ and L ２ 4) The phenanthroline compound according to 4), wherein is a single bond or an unsubstituted 1,4-phenylene group.

[0024] 6) The phenanthroline compound according to 5), wherein Ar in general formula (B) is an unsubstituted quinolyl group, an unsubstituted isoquinolyl group, an unsubstituted benzoxazolyl group, an unsubstituted benzothiazolyl group, an unsubstituted oxazolopyridyl group, an unsubstituted benzofuranyl group, or an unsubstituted benzothienyl group.

[0025] 7) An organic EL device having at least an anode electrode, a hole transport layer, a light-emitting layer, an electron transport layer, a cathode electrode, and a capping layer in this order, wherein the capping layer contains the phenanthroline compound represented by general formula (A) described in 1).

[0026] 8) The organic EL element according to 7), wherein the refractive index of a vapor-deposited film formed by vacuum-depositing the phenanthroline compound represented by general formula (A) on a silicon substrate to a thickness of 80 nm is 1.70 or more in the wavelength range of 450 nm to 750 nm, measured at room temperature (25° C.). 8') The organic EL element according to 7), wherein the capping layer has a thickness of 30 nm to 120 nm and a refractive index of 1.70 or more for light with a wavelength of 450 nm to 750 nm.

[0027] 9) The organic EL element according to 7), wherein the capping layer is a laminated or mixed layer composed of two or more compounds, and the capping layer contains at least one phenanthroline compound represented by general formula (A). 9') The organic EL element according to 7), wherein the capping layer contains two or more compounds, at least one of which is a phenanthroline compound represented by general formula (A). The capping layer here may be a mixed layer containing two or more compounds, or may have a laminated structure. Each layer constituting the laminated structure may be a single layer composed of one compound, or may be a mixed layer containing two or more compounds.

[0028] 10) An electronic device or electronic element having a pair of electrodes and at least one organic layer sandwiched between them, wherein the organic layer contains the phenanthroline compound represented by general formula (A) described in 1).

[0029] The phenanthroline compound of the present invention has a high refractive index and a low extinction coefficient for light with wavelengths of 450 nm to 750 nm, and therefore, by using the phenanthroline compound of the present invention as a material for the capping layer, an organic EL device with improved efficiency can be realized.

[0030] 1 is a diagram showing an example of the configuration of an organic EL element of the present invention.

[0031] The present invention will be described in detail below. The following description of the constituent elements may be based on representative embodiments and specific examples of the present invention, but the present invention is not limited to such embodiments and specific examples. In this specification, the term "to" is used to express a range, and for example, "5 to 10" means "5 to 10", and refers to a range that includes the numerical values ​​written before and after "to" as the lower and upper limits. A numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the lower and upper limits. Furthermore, the term "hydrogen atom" is used to express " １ H (protium) (normal hydrogen atom), and the term "deuterium atom" is ２ In this specification, "transparent" means that the transmittance of visible light is 50% or more, for example, 80% or more, for example, 90% or more, for example, 99% or more. The transmittance of visible light can be measured using an ultraviolet-visible spectrophotometer.

[0032] <Phenanthroline Compound Represented by General Formula (A)> The phenanthroline compound of the present invention has a structure represented by the following general formula (A).

[0033] In general formula (A), Ar represents an unsubstituted heteroaryl group. The "heteroaryl group" of the "unsubstituted heteroaryl group" represented by Ar may be a monocyclic heteroaryl group or may be composed of a fused ring formed by the fusion of two or more rings. Here, the multiple rings constituting the fused ring constituting the heteroaryl group may all be heterocyclic, or may contain a heterocyclic ring and a hydrocarbon ring (e.g., a benzene ring). The heterocyclic ring and hydrocarbon ring constituting the heteroaryl group may be aromatic or aliphatic, but the fused rings as a whole form an aromatic heterocyclic ring. Examples of heteroatoms contained in the heteroaryl group include a nitrogen atom, a sulfur atom, and an oxygen atom. The heteroaryl group may contain one heteroatom or two or more heteroatoms. When the heteroaryl group contains two or more heteroatoms, these heteroatoms may be the same or different. The number of atoms constituting the ring skeleton of the heteroaryl group is, for example, 4 to 40, 5 to 20, 5 to 16, or 6 to 14. The number of carbon atoms in the heteroaryl group is, for example, 3 to 35, and may be 3 to 30 or 2 to 20. Specific examples of the "heteroaryl group" include groups selected from heteroaryl groups having 2 to 20 carbon atoms, such as a pyridyl group, a pyrimidinyl group, a triazinyl group, a furyl group, a pyrrolyl group, a thienyl group, a quinolyl group, an isoquinolyl group, a benzofuranyl group, a benzothienyl group, an indolyl group, a carbazolyl group, a benzoxazolyl group, a benzothiazolyl group, an oxazolopyridyl group, a quinoxalinyl group, a quinazolinyl group, a benzimidazolyl group, a pyrazolyl group, a dibenzofuranyl group, a dibenzothienyl group, a naphthyridinyl group, a phenanthrolinyl group, an acridinyl group, and a carbolinyl group. Ar is preferably an unsubstituted 2-benzoxazolyl group, an unsubstituted 2-benzothiazolyl group, an unsubstituted 2-oxazolopyridyl group, an unsubstituted 2-benzofuranyl group, or an unsubstituted 2-benzothienyl group, and more preferably an unsubstituted 2-benzothiazolyl group or an unsubstituted 2-oxazolopyridyl group.

[0034] In general formula (A), L １ and L ２each independently represents a single bond, an arylene group, or a heteroarylene group. １ and L ２ may be the same or different. １ and L ２ The "arylene group" in the above formula (I) may be a monocyclic arylene group, or may be composed of a fused ring in which two or more rings are fused, or a linked ring in which two or more rings are linked by a single bond. Here, each of the rings constituting the fused rings constituting the arylene group may be an aromatic hydrocarbon ring (e.g., a benzene ring) or an aliphatic hydrocarbon ring, but the fused rings as a whole form an aromatic hydrocarbon ring. The number of carbon atoms in the arylene group is, for example, 6 to 40, and may be 6 to 30, 6 to 20, or 6 to 14. Specific examples of the "arylene group" include groups selected from arylene groups having 6 to 30 carbon atoms, such as a phenylene group, a biphenyl-diyl group, a terphenyl-diyl group, a naphthalene-diyl group, an anthracene-diyl group, a phenanthone-diyl group, a fluorene-diyl group, a spirobifluone-diyl group, an indene-diyl group, a pyrene-diyl group, a perylene-diyl group, a fluoranthene-diyl group, and a triphenylene-diyl group. １ and L ２ For the explanation of the "heteroarylene group" in the above, the description of the "heteroaryl group" in Ar can be referred to by replacing "heteroaryl group" with "heteroarylene group". Specific examples of the "heteroaryl group" include divalent groups obtained by removing one hydrogen atom from the specific groups given as examples of the "heteroaryl group" in Ar. １ and L ２ are preferably each independently a single bond or an arylene group, and L １ and L ２ It is also preferable that at least one of the following is a single bond. The arylene group is preferably a phenylene group, and more preferably a 1,4-phenylene group.

[0035] L １ and L ２The arylene group and heteroarylene group in the formula (I) may be unsubstituted, or at least one hydrogen atom of the arylene group and heteroarylene group may be substituted with an atom or group (herein, the "group" may be referred to as a "substituent") selected from the group consisting of a deuterium atom, a cyano group, a nitro group, a halogen atom, a silyl group, an alkyl group, an alkyloxy group, an alkenyl group, an aryloxy group, an arylalkyloxy group, an aryl group, and a heteroaryl group. Examples of the halogen atom, silyl group, alkyl group, alkyloxy group, alkenyl group, aryloxy group, arylalkyloxy group, aryl group, and heteroaryl group include the following, respectively. that is, halogen atoms such as fluorine, chlorine, bromine, and iodine; silyl groups such as trimethylsilyl and triphenylsilyl; linear or branched alkyl groups having 1 to 6 carbon atoms such as methyl, ethyl, and propyl; linear or branched alkyloxy groups having 1 to 6 carbon atoms such as methyloxy, ethyloxy, and propyloxy; alkenyl groups such as vinyl and allyl; aryloxy groups such as phenyloxy and tolyloxy; arylalkyloxy groups such as benzyloxy and phenethyloxy; aryl groups which are aromatic hydrocarbon groups or condensed polycyclic aromatic groups such as phenyl, biphenylyl, terphenylyl, naphthyl, anthracenyl, phenanthrenyl, fluorenyl, spirobifluorenyl, indenyl, pyrenyl, perylenyl, fluoranthenyl, and triphenylenyl; Examples of the substituent include heteroaryl groups such as pyridyl, thienyl, furyl, pyrrolyl, quinolyl, isoquinolyl, benzofuranyl, benzothienyl, indolyl, carbazolyl, benzoxazolyl, benzothiazolyl, quinoxalinyl, quinazolinyl, benzimidazolyl, pyrazolyl, dibenzofuranyl, dibenzothienyl, and carbolinyl. Other examples of the substituent include C aryl groups and C heteroaryl groups.These substituents may further be substituted with an atom or group selected from the group consisting of a deuterium atom, a cyano group, a nitro group, a halogen atom, a silyl group, an alkyl group, an alkyloxy group, an alkenyl group, an aryloxy group, an arylalkyloxy group, an aryl group, and a heteroaryl group. Furthermore, when these substituents are substituents on a benzene ring (including a benzene ring that is a constituent ring of a condensed ring), the benzene rings substituted with the substituents, or multiple substituents substituted on the same benzene ring, may 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. For examples of the substituents on the methylene group, please refer to the description of the substituents on the methylene group represented by X below.

[0036] In general formula (A), X represents a methylene group, an oxygen atom, or a sulfur atom, and at least one hydrogen atom of the methylene group may be substituted with an atom or group selected from the group consisting of a deuterium atom, a cyano group, a nitro group, a halogen atom, a silyl group, an alkyl group, an alkyloxy group, an alkenyl group, an aryloxy group, an arylalkyloxy group, an aryl group, and a heteroaryl group. Among these, the halogen atom, the silyl group, the alkyl group, the alkyloxy group, the alkenyl group, the aryloxy group, the arylalkyloxy group, the aryl group, and the heteroaryl group are described above with reference to L. １ and L ２ X is preferably a substituted or unsubstituted methylene group, and more preferably a dimethylmethylene group or an unsubstituted methylene group.

[0037] In general formula (A), A represents an unsubstituted phenanthrolinyl group. The phenanthrolinyl group is a monovalent group obtained by removing one hydrogen atom from a heterocycle (phenanthroline ring) in which two methine groups (=CH-) constituting the phenanthrene ring are replaced with nitrogen atoms. The positions of the nitrogen atoms in the phenanthrolinyl group are not particularly limited, but are preferably the 1st and 10th positions. That is, A in general formula (A) is preferably a 1,10-phenanthrolinyl group, and more preferably a 1,10-phenanthrolin-2-yl group.

[0038] In the phenanthroline compound represented by general formula (A), Ar-L １ - and Ar-L ２ The - may be bonded to any position of the benzene ring (the benzene ring constituting the ring skeleton) to which the bond is attached. In a preferred embodiment of the present invention, the phenanthroline compound represented by general formula (A) has a structure represented by the following general formula (B):

[0039]

[0040] A, Ar, and L in general formula (B) １ , L ２ and X represents A, Ar, L in general formula (A). １ , L ２ and X. A, Ar, and L in formula (B) １ , L ２ For the explanation of X, please refer to the corresponding description of general formula (A).

[0041] Preferred specific examples of the compound represented by general formula (A) are shown below, but the compounds represented by general formula (A) that can be used in the present invention should not be construed as being limited by these specific examples.

[0042]

[0043] <Method for synthesizing the compound represented by general formula (A)> The phenanthroline compound represented by general formula (A) is a novel compound. The compound represented by general formula (A) can be synthesized, for example, by a known coupling reaction using a palladium catalyst or the like (see, for example, Non-Patent Document 4).

[0044] The method for purifying the phenanthroline compound represented by general formula (A) is not particularly limited, and can be performed by known methods used for purifying organic compounds, such as purification by column chromatography, adsorption purification using silica gel, activated carbon, activated clay, etc., recrystallization purification using a solvent, crystallization purification, and sublimation purification, and the compound can be identified by NMR analysis. It is preferable to measure the melting point, glass transition point (Tg), refractive index, and extinction coefficient as physical property values ​​of the phenanthroline compound. The melting point is an index of vapor deposition property, the glass transition point (Tg) is an index of stability in the thin film state, and the refractive index and extinction coefficient are indexes related to improvement of light extraction efficiency.

[0045] The melting point and glass transition point (Tg) can be measured using a powder with a high-sensitivity differential scanning calorimeter (DSC3100SA, manufactured by Bruker AXS).

[0046] The refractive index and extinction coefficient can be measured by forming an 80 nm thin film on a silicon substrate and using a spectrophotometer (F10-RT-UV, manufactured by Filmetrics).

[0047] The phenanthroline compound represented by general formula (A) of the present invention has (1) a high refractive index in the wavelength range of 450 nm to 750 nm and (2) a low extinction coefficient. Furthermore, the phenanthroline compound represented by general formula (A) of the present invention is (3) vapor-depositable, (4) has a high glass transition temperature and is stable in a thin film state, and (5) has high heat resistance. Therefore, the phenanthroline compound represented by general formula (A) is useful as a material for the capping layer of an organic EL device. That is, by providing a capping layer containing the phenanthroline compound represented by general formula (A) on the outer side of the transparent or semitransparent electrode of an organic EL device, the light extraction efficiency is significantly improved, thereby realizing an organic EL device with high luminous efficiency and long life. Herein, the term "capping layer" refers to a layer disposed on the opposite side (outside) of at least one of the electrodes in an organic EL device having an emitting layer disposed between a pair of electrodes. The capping layer containing the compound represented by general formula (A) may be disposed on the outer side of only one of the pair of electrodes, or may be disposed on the outer side of both electrodes. An organic layer such as a charge transport layer may be disposed between the light-emitting layer and each electrode of the organic EL element to which the capping layer is applied.

[0048] <Organic Electroluminescence Device> Next, the organic electroluminescence device (organic EL device) of the present invention will be described. The organic EL device of the present invention has at least an anode electrode, a hole transport layer, an emitting layer, an electron transport layer, a cathode electrode, and a capping layer, in this order, and is characterized in that the capping layer contains a phenanthroline compound represented by general formula (A). For an explanation of the phenanthroline compound represented by general formula (A), please refer to the description in the above section "Phenanthroline Compound Represented by General Formula (A)." Examples of the structure of the organic EL device include, in the case of a light-emitting device with a top-emission structure, an anode, a hole transport layer, an emitting layer, an electron transport layer, a cathode, and a capping layer, arranged in this order on a substrate made of glass or the like. Other examples include a device having a hole injection layer between the anode and the hole transport layer, a device having an electron blocking layer between the hole transport layer and the emitting layer, a device having a hole blocking layer between the emitting layer and the electron transport layer, and a device having an electron injection layer between the electron transport layer and the cathode. In these multilayer structures, one organic layer can serve multiple roles, such as a structure that serves both as a hole injection layer and a hole transport layer, a structure that serves both as a hole transport layer and an electron blocking layer, a structure that serves both as a hole blocking layer and an electron transport layer, a structure that serves both as an electron transport layer and an electron injection layer, etc. Also, a structure in which two or more organic layers having the same function are laminated is possible, such as a structure in which two hole transport layers are laminated, a structure in which two light-emitting layers are laminated, a structure in which two electron transport layers are laminated, a structure in which two capping layers are laminated, etc.

[0049] The total thickness of each layer of the organic EL element is preferably 200 nm to 750 nm, more preferably 350 nm to 600 nm. The thickness of the capping layer is preferably, for example, 30 nm to 120 nm, more preferably 40 nm to 80 nm. In this case, good light extraction efficiency can be obtained. The thickness of the capping layer can be appropriately changed depending on the type of light-emitting material used in the light-emitting element, the thickness of the organic EL element other than the capping layer, and other factors. Each component and layer constituting the organic EL element will be described below.

[0050] [Anode] As the material for the anode of the organic EL element, an electrode material with a large work function, such as ITO (indium tin oxide) or gold, is used.

[0051] [Hole Injection Layer] Materials for the hole injection layer of an organic EL device include arylamine compounds having three or more triphenylamine structures in the molecule, with these triphenylamine structures linked by a single bond or a divalent group not containing a heteroatom. Examples of arylamine compounds include starburst triphenylamine derivatives and various triphenylamine tetramers. Materials for the hole injection layer include porphyrin compounds such as copper phthalocyanine, acceptor heterocyclic compounds such as hexacyanoazatriphenylene, and coating-type polymeric materials. The hole injection layer may be composed of a single layer formed from one of these hole injection materials, or a mixed layer formed from a mixture of two or more materials. The hole injection layer may have a single layer structure, a laminate structure of layers formed from a single material or a mixture of layers, or a laminate structure of layers formed from a single material and a mixture of layers. These materials can be formed into thin films by known methods such as vapor deposition, spin coating, and inkjet printing.

[0052] [Hole Transport Layer] Materials that can be used for the hole transport layer of an organic EL device include benzidine derivatives such as N,N'-diphenyl-N,N'-di(m-tolyl)benzidine (hereinafter abbreviated as TPD), N,N'-diphenyl-N,N'-di(α-naphthyl)benzidine, and N,N,N',N'-tetrabiphenylylbenzidine, as well as 1,1-bis[4-(di-4-tolylamino)phenyl]cyclohexane. In particular, it is preferable to use an arylamine compound having two triphenylamine structures in the molecule, where these triphenylamine structures are linked by a single bond or a divalent group not containing a heteroatom, such as N,N,N',N'-tetrabiphenylylbenzidine. It is also preferable to use an arylamine compound having three or more triphenylamine structures in the molecule, where these triphenylamine structures are linked by a single bond or a divalent group not containing a heteroatom, such as various triphenylamine trimers and tetramers. The hole transport layer may be composed of a single layer formed from one of these hole transport materials alone, or a mixed layer formed from a mixture of two or more materials. The hole transport layer may have a single layer structure, a laminated structure formed from layers formed from a single material or a mixed layer, or a laminated structure formed from a layer formed from a single material and a mixed layer. Coating-type polymer materials such as poly(3,4-ethylenedioxythiophene) / poly(styrene sulfonate) can be used as the hole injection / transport layer. These materials can be formed into thin films by known methods such as vapor deposition, spin coating, and inkjet printing.

[0053] Furthermore, as materials for the hole injection layer and the hole transport layer, materials that are typically used for these layers and that are doped with a p-type dopant such as trisbromophenylaminehexachloroantimony or a radialene derivative (see, for example, Patent Document 3), as well as polymer compounds that contain the structure of a benzidine derivative such as TPD as a partial structure, can be used.

[0054] [Electron Blocking Layer] The organic EL device of the present invention may have an electron blocking layer between the light-emitting layer and the hole-transporting layer. Materials that can be used for the electron blocking layer include compounds having an electron blocking effect, such as carbazole derivatives such as 4,4',4''-tri(N-carbazolyl)triphenylamine (hereinafter abbreviated as TCTA), 9,9-bis[4-(carbazol-9-yl)phenyl]fluorene, 1,3-bis(carbazol-9-yl)benzene (hereinafter abbreviated as mCP), and 2,2-bis(4-carbazol-9-ylphenyl)adamantane, and compounds having a triphenylsilyl group and a triarylamine structure, typified by 9-[4-(carbazol-9-yl)phenyl]-9-[4-(triphenylsilyl)phenyl]-9H-fluorene. The electron blocking layer may be formed as a single layer using one of these electron blocking materials alone, or as a mixed layer using a mixture of two or more materials. The electron blocking layer may have a single layer structure, a laminate structure of layers formed independently or in combination, or a laminate structure of layers formed independently and in combination. These materials can be formed into thin films by known methods such as vapor deposition, spin coating, and ink jet printing.

[0055] [Light-emitting layer] As a material for the light-emitting layer of the organic EL element, tris(8-quinolinolato)aluminum (Alq ３Light-emitting materials that can be used include metal complexes of quinolinol derivatives such as quinolinol derivatives (e.g., quinolinol derivatives), various metal complexes, anthracene derivatives, bisstyrylbenzene derivatives, pyrene derivatives, oxazole derivatives, and polyparaphenylenevinylene derivatives. The light-emitting layer may also be composed of a host material and a dopant material. Anthracene derivatives are preferably used as the host material. Other examples include the above-mentioned light-emitting materials, heterocyclic compounds having an indole ring as a fused ring substructure, heterocyclic compounds having a carbazole ring as a fused ring substructure, carbazole derivatives, thiazole derivatives, benzimidazole derivatives, and polydialkylfluorene derivatives. Dopant materials that can be used include quinacridone, coumarin, rubrene, perylene, and their derivatives, benzopyran derivatives, rhodamine derivatives, and aminostyryl derivatives. Green light-emitting materials are particularly preferred. The light-emitting layer may be composed of a single layer formed by depositing one of the above light-emitting materials alone, or may be composed of a Kondo layer formed by mixing two or more materials (for example, two or more light-emitting materials, or one or more host materials and one or more dopant materials). The light-emitting layer may have a single-layer structure, or a laminate structure in which layers formed by depositing alone or layers formed by mixing the materials are laminated, or a laminate structure in which a layer formed by depositing alone and a layer formed by mixing the materials are laminated.

[0056] It is also possible to use a phosphorescent emitter as the light-emitting material. As the phosphorescent emitter, a phosphorescent emitter of a metal complex such as iridium or platinum can be used. For example, Ir(ppy) ３ green phosphorescent emitters such as FIrpic (bis[2-(4,6-difluorophenyl)pyridinato-C2,N](picolinato)iridium(III)) and FIr6 (bis(2,4-difluorophenylpyridinato)tetrakis(1-pyrazolyl)borate iridium(III)); ２Red phosphorescent emitters such as Ir(acac) (bis(2-benzo[b]thiophen-2-yl-pyridine)(acetylacetonato)iridium(III)) can be used, and green phosphorescent emitters are particularly preferred. The light-emitting layer may be composed solely of these phosphorescent emitters, or may be composed of a host material and a phosphorescent emitter (e.g., a co-deposited film of a host material and a phosphorescent emitter). Carbazole derivatives such as 4,4'-di(N-carbazolyl)biphenyl, TCTA, and mCP can be used as hole-injecting / transporting host materials, and p-bis(triphenylsilyl)benzene and 2,2',2''-(1,3,5-phenylene)-tris(1-phenyl-1H-benzimidazole) can be used as electron-transporting host materials.

[0057] The amount of phosphorescent material doped into the host material is preferably in the range of 1 to 30 weight percent based on the total weight of the light-emitting layer in order to avoid concentration quenching.

[0058] Furthermore, as the light-emitting material, it is also possible to use materials that emit delayed fluorescence, such as carbazolyldicyanobenzene (CDCB) derivatives such as PIC-TRZ, CC2TA, PXZ-TRZ, and 4CzIPN (see, for example, Non-Patent Document 5). These materials can be formed into thin films by known methods such as vapor deposition, spin coating, and inkjet printing.

[0059] [Hole Blocking Layer] The organic EL device of the present invention may have a hole blocking layer between the light-emitting layer and the electron-transporting layer. Examples of materials for the hole blocking layer include phenanthroline derivatives such as bathocuproine, metal complexes of quinolinol derivatives such as aluminum(III) bis(2-methyl-8-quinolinato)-4-phenylphenolate (hereinafter abbreviated as BAlq), various rare earth complexes, triazole derivatives, triazine derivatives, pyrimidine derivatives, oxadiazole derivatives, and benzoazole derivatives, all of which have hole-blocking properties. These materials may also be used as materials for the electron-transporting layer. The electron blocking layer may be composed of a single layer formed from one of these electron-blocking materials, or a mixed layer formed from a mixture of two or more materials. The hole blocking layer may have a single layer structure, a laminate structure formed from layers formed from a single material or a mixture of layers formed from a single material, or a laminate structure formed from a layer formed from a mixture of layers formed from a single material and a layer formed from a mixture of layers. These materials can be used to form thin films by known methods such as vapor deposition, spin coating, and ink jet printing.

[0060] [Electron Transport Layer] Alq was used as a material for the electron transport layer of the organic EL element. ３ Metal complexes of quinolinol derivatives such as BAlq, various metal complexes, triazole derivatives, triazine derivatives, pyrimidine derivatives, oxadiazole derivatives, pyridine derivatives, benzimidazole derivatives, benzoazole derivatives, thiadiazole derivatives, anthracene derivatives, carbodiimide derivatives, quinoxaline derivatives, pyridoindole derivatives, phenanthroline derivatives, and silole derivatives can be used. The electron transport layer may be composed of a single layer formed from one of these electron transport materials alone, or a mixed layer formed from a mixture of two or more materials. The electron transport layer may also have a single layer structure, a laminate structure formed from layers formed from a single material or a mixture of layers, or a laminate structure formed from a layer formed from a single material and a layer formed from a mixture of layers. These materials can be formed into thin films by known methods such as vapor deposition, spin coating, and inkjet printing.

[0061] [Electron injection layer] Materials that can be used for the electron injection layer of an organic EL device include alkali metal salts such as lithium fluoride and cesium fluoride, alkaline earth metal salts such as magnesium fluoride, metal complexes of quinolinol derivatives such as lithium quinolinol, metal oxides such as aluminum oxide, and metals such as ytterbium (Yb), samarium (Sm), calcium (Ca), strontium (Sr), and cesium (Cs). The electron injection layer can be omitted by selecting the electron transport layer and the cathode appropriately.

[0062] Furthermore, materials that are normally used for the electron injection layer and the electron transport layer can be doped with an n-type metal dopant such as cesium.

[0063] [Cathode] Materials used for the cathode of an organic EL element include metals with a low work function such as aluminum, alloys with even lower work functions such as magnesium-silver alloys, magnesium-calcium alloys, magnesium-indium alloys, and aluminum-magnesium alloys, and conductive transparent materials such as ITO (indium tin oxide) and IZO (indium zinc oxide). Metals and alloys are formed to a thin thickness of about 10 to 200 nm to form a semitransparent cathode electrode.

[0064] [Capping Layer] The organic EL device of the present invention contains a phenanthroline compound represented by general formula (A) in the capping layer. The capping layer may be a single layer formed by depositing a single phenanthroline compound selected from the group of compounds represented by general formula (A), a mixed layer formed by mixing two or more phenanthroline compounds selected from this group of compounds, or a mixed layer formed by mixing a phenanthroline compound selected from this group of compounds with a material other than the phenanthroline compound represented by general formula (A). The capping layer may have a single layer structure, a laminated structure formed by laminating layers formed by depositing single layers or layers formed by mixing layers, or a laminated structure formed by laminating a layer formed by depositing a single layer and a layer formed by mixing layers. These materials can be formed into thin films by known methods such as vapor deposition, spin coating, and inkjet printing.

[0065] In the organic EL device, the thickness of the capping layer is preferably in the range of 30 nm to 120 nm, and particularly preferably in the range of 40 nm to 80 nm.

[0066] Furthermore, the capping layer containing the phenanthroline compound represented by general formula (A) preferably has a refractive index of 1.70 or more, particularly preferably 1.85 or more, for light with a wavelength of 450 nm to 700 nm.

[0067] While the present invention has been described above using an organic EL element with a top emission structure as an example, the organic EL element to which the present invention is applicable is not limited to this, and may also be an organic EL element with a bottom emission structure or an organic EL element with a dual emission structure that emits light from both the top and bottom. For descriptions of the components and layers constituting organic EL elements with a bottom emission structure and a dual emission structure, please refer to the description of the organic EL element above. However, it is preferable that the electrode in the direction in which light is extracted from the light-emitting element to the outside be transparent or semitransparent. That is, in a bottom emission structure, the electrode on the substrate side is preferably transparent or semitransparent, and in a dual emission structure, it is preferable that both electrodes are transparent or semitransparent.

[0068] <Electronic Device and Electronic Element> The electronic device and electronic element of the present invention have a pair of electrodes and at least one organic layer disposed between the pair of electrodes, and at least one of the organic layers contains a compound represented by general formula (I). For an explanation of the compound represented by general formula (I), please refer to the description in the above section <Compound represented by general formula (I)>. Examples of the electronic device include display devices and light-emitting devices equipped with organic EL elements, as well as electrophotographic photoreceptors, image sensors, photoelectric conversion elements, solar cells, etc. Examples of the display device include display components such as organic EL panel modules, televisions, mobile phones, tablets, personal computers, etc. Examples of the light-emitting device include lighting or vehicle lamps, etc.

[0069] Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples as long as it does not depart from the gist of the invention.

[0070] Example 1 Synthesis of 2-(4-(9,9-dimethyl-7-(1,10-phenanthroline-2-yl)-9H-fluoren-2-yl)phenyl)dibenzothiazole (Compound 30) A reaction vessel was charged with 5.0 g of 2-bromo-1,10-phenanthroline, 11.2 g of 2-(4-(9,9-dimethyl-7-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9H-fluoren-2-yl)phenyl)benzothiazole, 0.5 g of tetrakis(triphenylphosphine)palladium(0), and 5.3 g of potassium carbonate, and the mixture was diluted with toluene / EtOH / H ２ The mixture was refluxed and stirred overnight in a 0 mixed solvent. After allowing to cool, MeOH was added, and the precipitated solid was filtered to obtain a crude product. The obtained crude product was purified by crystallization using a monochlorobenzene / acetone mixed solvent to obtain 12.3 g (yield: 70.7%) of a white powder of 2-(4-(9,9-dimethyl-7-(1,10-phenanthrolin-2-yl)-9H-fluoren-2-yl)phenyl)dibenzothiazole (Compound 30).

[0071]

[0072] The structure of the resulting white powder was identified using NMR. １ H-NMR (CDCl ３ ), the following 27 hydrogen signals were detected, and it was confirmed to be compound 30. δ (ppm) = 9.27 (1H), 8.42 (1H), 8.34 (2H), 8.29 (1H), 8.26 (3H), 8.11 (1H), 7.94 (2H), 7.90 (1H), 7.83 (4H), 7.76 (1H), 7.69 (1H), 7.67 (1H), 7.52 (1H), 7.41 (1H), 1.69 (6H).

[0073] Example 2 Synthesis of 2-(4-(9,9-dimethyl-7-(1,10-phenanthroline-2-yl)-9H-fluoren-2-yl)phenyl)oxazolo[5,4-b]pyridine (Compound 31) A reaction vessel was charged with 3.0 g of 2-bromo-1,10-phenanthroline, 6.6 g of 2-(4-(9,9-dimethyl-7-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9H-fluoren-2-yl)phenyl)oxazolo[5,4-b]pyridine, 0.3 g of tetrakis(triphenylphosphine)palladium(0), and 3.2 g of potassium carbonate, and the mixture was diluted with toluene / EtOH / H ２ The mixture was refluxed and stirred overnight in a 0 mixed solvent. After allowing to cool, MeOH was added, and the precipitated solid was filtered to obtain a crude product. The obtained crude product was purified by crystallization using a monochlorobenzene / acetone mixed solvent to obtain 3.2 g (yield: 48.5%) of a white powder of 2-(4-(9,9-dimethyl-7-(1,10-phenanthrolin-2-yl)-9H-fluoren-2-yl)phenyl)oxazolo[5,4-b]pyridine (Compound 31).

[0074]

[0075] The structure of the resulting white powder was identified using NMR. １ H-NMR (CDCl ３ ), the following 26 hydrogen signals were detected, and it was confirmed to be compound 31. δ (ppm) = 9.26 (1H), 8.44 (1H), 8.40 (2H), 8.37 (1H), 8.34 (1H), 8.33 (1H), 8.28 (1H), 8.18 (1H), 8.09 (1H), 7.93 (1H), 7.91 (1H), 7.88 (2H), 7.82 (2H), 7.78 (1H), 7.70 (1H), 7.67 (1H), 7.38 (1H), 1.70 (6H).

[0076] Example 3 Synthesis of 2-(7-(4-(1,10-phenanthrolin-2-yl)phenyl)-9,9-dimethyl-9H-fluoren-2-yl)benzoxazole (Compound 38) A reaction vessel was charged with 2.5 g of 2-chlorobenzoxazole, 10.3 g of 2-(4-(9,9-dimethyl-7-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9H-fluoren-2-yl)phenyl)-1,10-phenanthroline, 0.4 g of tetrakis(triphenylphosphine)palladium(0), and 4.5 g of potassium carbonate, and the mixture was diluted with toluene / EtOH / H ２ The mixture was refluxed and stirred overnight in a 0 mixed solvent. After allowing to cool, MeOH was added, and the precipitated solid was filtered to obtain a crude product. The obtained crude product was purified by crystallization using a monochlorobenzene / acetone mixed solvent to obtain 5.7 g (yield: 61.9%) of a white powder of 2-(7-(4-(1,10-phenanthrolin-2-yl)phenyl)-9,9-dimethyl-9H-fluoren-2-yl)benzoxazole (Compound 38).

[0077]

[0078] The structure of the resulting white powder was identified using NMR. １ H-NMR (CDCl ３ ), the following 27 hydrogen signals were detected, and it was confirmed to be compound 38. δ (ppm) = 9.27 (1H), 8.49 (2H), 8.39 (1H), 8.33 (1H), 8.28 (2H), 8.18 (1H), 7.89 (3H), 7.87 (1H), 7.81 (4H), 7.73 (1H), 7.66 (1H), 7.62 (1H), 7.37 (2H), 1.66 (6H).

[0079] Example 4 Synthesis of 2-(7-(4-(1,10-phenanthroline-2-yl)phenyl)-9,9-dimethyl-9H-fluoren-2-yl)benzothiazole (Compound 39) A reaction vessel was charged with 10.0 g of 2-(4-bromophenyl)-1,10-phenanthroline, 14.9 g of 2-(9,9-dimethyl-7-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9H-fluoren-2-yl)benzothiazole, 0.7 g of tetrakis(triphenylphosphine)palladium(0), and 8.3 g of potassium carbonate, and the mixture was diluted with toluene / EtOH / H ２ The mixture was refluxed and stirred overnight in a toluene / acetone mixed solvent. After cooling, MeOH was added and the precipitated solid was filtered to obtain a crude product. The obtained crude product was purified by crystallization using a toluene / acetone mixed solvent to obtain 12.3 g (yield: 70.7%) of a white powder of 2-(7-(4-(1,10-phenanthrolin-2-yl)phenyl)-9,9-dimethyl-9H-fluoren-2-yl)benzothiazole (Compound 39).

[0080]

[0081] The structure of the resulting white powder was identified using NMR. １ H-NMR (CDCl ３ ), the following 27 hydrogen signals were detected, and it was confirmed to be compound 39. δ (ppm) = 9.28 (1H), 8.49 (2H), 8.33 (1H), 8.28 (1H), 8.26 (1H), 8.18 (1H), 8.11 (1H), 8.07 (1H), 7.93 (1H), 7.89-7.77 (7H), 7.73 (1H), 7.66 (1H), 7.52 (1H), 7.40 (1H), 1.67 (6H).

[0082] [Example 5] The melting points and glass transition points (Tg) of the compounds obtained in Examples 1 to 4 were measured using a high-sensitivity differential scanning calorimeter (DSC3100SA, manufactured by Bruker AXS). The measurement results are shown in Table 1.

[0083]

[0084] From the results shown in Table 1, it can be seen that the compounds obtained in Examples 1 to 4 have high melting points and glass transition points of 100° C. or higher, which indicates that the thin film state is stable.

[0085] [Example 6] Using the compounds obtained in Examples 1 to 4, a vapor-deposited film having a thickness of 80 nm was formed on a silicon substrate, and the refractive index n and extinction coefficient k at wavelengths of 450 nm and 750 nm were measured using a spectrophotometer (F10-RT-UV, manufactured by Filmetrics). ３ The measurement was also carried out for a comparative compound (CPL-1) of the following structural formula (see, for example, Patent Document 4). The measurement results are summarized in Table 2.

[0086]

[0087]

[0088] As shown in Table 2, the phenanthroline compound of the present invention exhibits a high affinity for Alq at wavelengths between 450 nm and 750 nm. ３ and a higher refractive index than that of the comparative compound (CPL-1). These results demonstrate that the use of the phenanthroline compound of the present invention as a constituent material of the capping layer can be expected to improve the light extraction efficiency of an organic EL device.

[0089] Example 7 As shown in FIG. 1 , a reflective ITO electrode was previously formed as a transparent anode 2 on a glass substrate 1, and a hole injection layer 3, a hole transport layer 4, a light-emitting layer 5, an electron transport layer 6, an electron injection layer 7, a cathode 8, and a capping layer 9 were deposited in this order on the substrate to prepare an organic EL device.

[0090] Specifically, a glass substrate 1 on which a 50 nm thick ITO film, a 100 nm thick silver alloy reflective film, and a 5 nm thick ITO film were sequentially formed was subjected to ultrasonic cleaning in isopropyl alcohol for 20 minutes and then dried for 10 minutes on a hot plate heated to 250°C. This was then subjected to UV ozone treatment for 2 minutes, after which the ITO-coated glass substrate was mounted in a vacuum deposition machine and the pressure was reduced to 0.001 Pa or less. Subsequently, a hole injection layer 3 was formed covering the transparent anode 2 by binary deposition of an electron acceptor (Acceptor-1) of the following structural formula and a compound (HTM-1) of the following structural formula at a deposition rate ratio of Acceptor-1:compound (HTM-1) = 3:97, to a thickness of 10 nm.

[0091] On the hole injection layer 3, a compound (HTM-1) having the following structural formula was formed as a hole transport layer 4 to a thickness of 140 nm. On this hole transport layer 4, a compound (EMD-1) having the following structural formula and a compound (EMH-1) having the following structural formula were formed as a light-emitting layer 5 by binary deposition at a deposition rate ratio of (EMD-1):(EMH-1) = 5:95 to form a layer of 20 nm. On this light-emitting layer 5, a compound (ETM-1) having the following structural formula and a compound (ETM-2) having the following structural formula were formed as an electron transport layer 6 by binary deposition at a deposition rate ratio of (ETM-1):(ETM-2) = 50:50 to form a layer of 30 nm. On this electron transport layer 6, lithium fluoride was formed as an electron injection layer 7 to a thickness of 1 nm. On this electron injection layer 7, a magnesium-silver alloy was formed as a cathode 8 to a thickness of 12 nm.

[0092] Finally, the compound (30) of Example 1 was formed to a thickness of 60 nm as a capping layer 9. The characteristics of the produced organic EL device were measured in the atmosphere at room temperature, and the measurement results of the light-emitting characteristics when a DC voltage was applied are summarized in Table 3.

[0093]

[0094] [Examples 8 to 10] Organic EL devices were fabricated under the same conditions as in Example 7, except that the compounds obtained in Examples 2 to 4 were used as the capping layer 9 instead of compound (30) in Example 1. The characteristics of the fabricated organic EL devices were measured in the atmosphere at room temperature, and the measurement results of the luminescence characteristics when a DC voltage was applied are summarized in Table 3.

[0095] Comparative Example 1 For comparison, in Example 7, Alq was used as the capping layer 9 instead of the compound (30) in Example 1. ３ The organic EL devices were fabricated under the same conditions except that the organic EL elements were used. The characteristics of the fabricated organic EL devices were measured in the atmosphere at room temperature, and the measurement results of the light-emitting characteristics when a DC voltage was applied are summarized in Table 3.

[0096] For comparison, an organic EL device was prepared under the same conditions as in Example 7, except that compound (CPL-1) was used as the capping layer 9 instead of compound (30) in Example 1. The characteristics of the prepared organic EL device were measured in the atmosphere at room temperature, and the measurement results of the luminescence characteristics when a DC voltage was applied are summarized in Table 3.

[0097] The organic EL elements fabricated in the examples and comparative examples were used to measure the element characteristics and element lifespan, and the results are summarized in Table 3. The element lifespan measured in the present invention was 10 mA / cm ２ The time required for the initial luminance to decay to 95% of 100% when the device was driven at a constant current of 100% was measured.

[0098]

[0099] As shown in Table 3, the current density was 10 mA / cm ２ The driving voltage at this time was almost the same for the devices of Comparative Examples 1 and 2 and the devices of Examples 7 to 10, whereas the devices of Examples showed significant improvements in brightness, luminous efficiency, power efficiency, and device life compared to the devices of Comparative Examples. This indicates that the phenanthroline compound of the present invention represented by general formula (A) is a material that can be suitably used for the capping layer, and that increasing the refractive index of the capping layer can significantly improve the light extraction efficiency of the organic EL device.

[0100] The phenanthroline compound of the present invention has a high refractive index, can significantly improve light extraction efficiency, and is stable in a thin film state, making it an excellent compound suitable for use in organic EL devices. Furthermore, organic EL devices fabricated using the phenanthroline compound of the present invention can achieve high efficiency. Furthermore, the use of the compound of the present invention, which has no absorption in the blue, green, and red wavelength regions, is particularly suitable for displaying clear, bright images with good color purity. For example, the compound can be expected to be used in home appliances and lighting.

[0101] REFERENCE SIGNS LIST 1 Glass substrate 2 Transparent anode 3 Hole injection layer 4 Hole transport layer 5 Light-emitting layer 6 Electron transport layer 7 Electron injection layer 8 Cathode 9 Capping layer

Claims

1. A phenanthroline compound represented by the following general formula (A): 【Chemistry 1】 (In the formula, Ar represents an unsubstituted heteroaryl group. L １ and L ２ one represents a single bond and the other represents an arylene group, and at least one hydrogen atom of the arylene group may be substituted with an atom or group selected from the group consisting of a deuterium atom, a cyano group, a nitro group, a halogen atom, a silyl group, an alkyl group, an alkyloxy group, an alkenyl group, an aryloxy group, an arylalkyloxy group, an aryl group, and a heteroaryl group. X represents a methylene group, an oxygen atom, or a sulfur atom, and at least one hydrogen atom of the methylene group may be substituted with an atom or group selected from the group consisting of a deuterium atom, a cyano group, a nitro group, a halogen atom, a silyl group, an alkyl group, an alkyloxy group, an alkenyl group, an aryloxy group, an arylalkyloxy group, an aryl group, and a heteroaryl group. A represents an unsubstituted phenanthrolinyl group.

2. 2. The phenanthroline compound according to claim 1, wherein A in the general formula (A) is an unsubstituted 1,10-phenanthrolinyl group.

3. 3. The phenanthroline compound according to claim 2, wherein the general formula (A) is the following general formula (B): 【Chemistry 2】 (In the formula, A represents an unsubstituted 1,10-phenanthrolinyl group. Ar, L １ , L ２ and X is as defined in the general formula (A).

4. 4. The phenanthroline compound according to claim 3, wherein X in general formula (B) is a methylene group, and at least one hydrogen atom of the methylene group may be substituted with an atom or group selected from the group consisting of a deuterium atom, a cyano group, a nitro group, a halogen atom, a silyl group, an alkyl group, an alkyloxy group, an alkenyl group, an aryloxy group, an arylalkyloxy group, an aryl group, and a heteroaryl group.

5. L in the general formula (B) １ and L ２ The phenanthroline compound according to claim 4, wherein one of the groups is a single bond and the other is an unsubstituted 1,4-phenylene group.

6. The phenanthroline compound according to claim 5, wherein Ar in the general formula (B) is an unsubstituted quinolyl group, an unsubstituted isoquinolyl group, an unsubstituted benzoxazolyl group, an unsubstituted benzothiazolyl group, an unsubstituted oxazolopyridyl group, an unsubstituted benzofuranyl group, or an unsubstituted benzothienyl group.

7. An organic EL device having at least an anode electrode, a hole transport layer, an emitting layer, an electron transport layer, a cathode electrode, and a capping layer in this order, wherein the capping layer contains a phenanthroline compound represented by the following general formula (A): 【Transformation 3】 (In the formula, Ar represents an unsubstituted heteroaryl group. L 1 represents a single bond, an arylene group, or a heteroarylene group, L 2 represents a single bond or an arylene group, and at least one hydrogen atom of the arylene group and the heteroarylene group may be substituted with an atom or group selected from the group consisting of a deuterium atom, a cyano group, a nitro group, a halogen atom, a silyl group, an alkyl group, an alkyloxy group, an alkenyl group, an aryloxy group, an arylalkyloxy group, an aryl group, and a heteroaryl group. X represents a methylene group, an oxygen atom, or a sulfur atom, and at least one hydrogen atom of the methylene group may be substituted with an atom or group selected from the group consisting of a deuterium atom, a cyano group, a nitro group, a halogen atom, a silyl group, an alkyl group, an alkyloxy group, an alkenyl group, an aryloxy group, an arylalkyloxy group, an aryl group, and a heteroaryl group. A represents an unsubstituted phenanthrolinyl group.

8. 8. The organic EL device according to claim 7, wherein a vapor-deposited film of the phenanthroline compound represented by general formula (A) vacuum-deposited on a silicon substrate to a thickness of 80 nm has a refractive index of 1.70 or more in the wavelength range of 450 nm to 750 nm, measured at room temperature (25°C).

9. 8. The organic EL element according to claim 7, wherein the capping layer is a laminated or mixed layer made of two or more compounds, and the capping layer contains at least one phenanthroline compound represented by general formula (A).

10. 10. An electronic device or electronic element having a pair of electrodes and at least one organic layer sandwiched between them, wherein the organic layer contains the phenanthroline compound represented by general formula (A) according to claim 1.

Images