Compound, light-emitting element comprising same, display device, illumination device, and

Abstract

The present invention addresses the problem of providing an organic EL element having excellent luminous efficiency and durability life. A compound represented by general formula (1). (In general formula (1), R1 and R2 are each independently selected from the group consisting of a substituted or unsubstituted aryl group and a substituted or unsubstituted heteroaryl group. R1 and R2 may be linked to each other to form a ring structure. And R3 is selected from the group consisting of substituted or unsubstituted alkyl, substituted or unsubstituted aryl and substituted or unsubstituted heteroaryl. And L is a substituted or unsubstituted arylene group, or a substituted or unsubstituted heteroarylene group. A is a structure represented by general formula (2) or (3). ) (In general formulae (2) and (3), R4 to R14 are each independently selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heteroaryl group. Wherein one of R4-R11 or R12-R14 is directly connected with the L. R7 and R8 may be connected to each other to form a ring structure. And X1-X8 each independently represents a carbon atom or a nitrogen atom. In this connection, at least one of X1 and X2 is a nitrogen atom, and at least one of X3 to X8 is a nitrogen atom. > # imgabs0 #

Description

Technical Field

[0001] The present invention relates to a compound, a light-emitting element, a display device, a lighting device, and a photosensitizer using the same. Background Art

[0002] In recent years, organic EL devices have steadily been put into practical use in applications such as televisions and smartphone displays. However, existing organic EL devices still face numerous technical challenges. Among these, achieving high-efficiency light emission while extending the life of organic EL devices has become a major challenge.

[0003] As compounds to solve these problems, imidazophenanthroline derivatives substituted with specific aryl or heteroaryl groups (for example, see Patent Document 1), imidazophenanthroline derivatives having a benzoacridine skeleton (for example, see Patent Document 2), and imidazole derivatives substituted with specific aryl and heteroaryl groups (for example, see Patent Documents 3 and 4) have been developed so far.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: China Patent Application Publication No. 101024765

[0007] Patent Document 2: International Publication No. 2015 / 083948

[0008] Patent Document 3: Korean Patent Application Publication No. 2009-0079134

[0009] Patent Document 4: Korean Patent Application Publication No. 2020-0076818 Summary of the Invention

[0010] Problems to be solved by the invention

[0011] The technologies described in Patent Documents 1 to 4 enable the production of organic EL devices that have improved luminous efficiency, enable low-voltage operation, and exhibit excellent durability. However, the luminous efficiency and durability required of organic EL devices have been increasing in recent years, and technologies are needed to achieve both higher luminous efficiency and a longer lifespan.

[0012] The present invention has been made in view of the above-mentioned problems in the prior art, and an object of the present invention is to provide an organic EL element having excellent luminous efficiency and durable life.

[0013] Means for solving problems

[0014] In order to solve the above-mentioned problems, the present invention adopts the following configuration.

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

[0016] [Chemical Formula 1]

[0017]

[0018] In the general formula (1), R 1 and R 2 are each independently selected from the group consisting of substituted or unsubstituted aryl and substituted or unsubstituted heteroaryl. 1 and R 2 They can be connected to each other to form a ring structure. 3 is selected from the group consisting of a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heteroaryl group. L is a substituted or unsubstituted arylene group, or a substituted or unsubstituted heteroarylene group. A is a structure represented by the following general formula (2) or (3).

[0019] [Chemical Formula 2]

[0020]

[0021] [Chemical Formula 3]

[0022]

[0023] In general formulas (2) and (3), R 4 ~R 14 are each independently selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heteroaryl group. 4 ~R 11 One of them is directly connected to L, R 12 ~R 14 One of them is directly connected to L. 7 and R 8 Can be connected to each other to form a ring structure. 1 ~X 8 Each independently represents a carbon atom or a nitrogen atom. 1 and X 2 At least one of X is a nitrogen atom, 3 ~X 8 At least one of them is a nitrogen atom.

[0024] [2] The compound described in [1] above, wherein in the general formula (1), R 1 and R 2 The total number of carbon atoms in is 8 to 20.

[0025] [3] The compound according to [1] or [2], wherein in the general formula (1), R 3The number of carbon atoms in is 1 to 12.

[0026] [4] The compound according to any one of [1] to [3], wherein in the general formula (1), L is a phenylene group, a naphthylene group, or a biphenylene group.

[0027] [5] The compound according to any one of [1] to [4], wherein in the general formula (1), A is represented by any one of the following general formulas (4) to (6).

[0028] [Chemical Formula 4]

[0029]

[0030] [Chemical Formula 5]

[0031]

[0032] [Chemical Formula 6]

[0033]

[0034] In general formulas (4) to (6), R 4 ~R 10 、R 15 and R 16 Each is independently selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heteroaryl group. 3 ~X 6 Each independently represents a carbon atom or a nitrogen atom. 3 ~X 6 At least one of them is a nitrogen atom. * indicates the position of connection with L.

[0035] [6] The compound according to any one of the above [5], wherein in the above general formulas (4) and (5), R 5 ~R 10 、R 15 and R 16 A hydrogen atom.

[0036] [7] The compound described in [5] or [6] above, wherein in the general formula (6), X 3 is a nitrogen atom and X 4 ~X 6 Any one of them is a nitrogen atom.

[0037] [8] A light-emitting element comprising at least an electron transport layer and a light-emitting layer between an anode and a cathode, and emitting light using electrical energy, wherein the electron transport layer contains the compound according to any one of [1] to [7].

[0038] [9] The light-emitting element according to [8], wherein the electron transport layer further contains alkali metal atoms or rare earth metal atoms.

[0039]

[10] A light-emitting element comprising at least a charge generation layer and a light-emitting layer between an anode and a cathode, and emitting light using electrical energy, wherein the charge generation layer contains the compound described in any one of [1] to [7].

[0040]

[11] The light-emitting element according to

[10] , wherein the charge generation layer further contains a phenanthroline derivative.

[0041]

[12] The light-emitting element according to

[10] or

[11] , wherein the charge generation layer further contains alkali metal atoms, copper group atoms, or rare earth metal atoms.

[0042]

[13] The light-emitting element according to any one of

[10] to

[12] , wherein the charge generation layer further contains an alkali metal atom, and the alkali metal atom is Li.

[0043]

[14] The light-emitting element according to

[11] , wherein the charge generation layer further contains rare earth metal atoms, and the rare earth metal atoms are Yb.

[0044]

[15] A light-emitting element comprising at least an electron injection layer and a light-emitting layer between an anode and a cathode, and emitting light using electrical energy, wherein the electron injection layer contains the compound according to any one of [1] to [7].

[0045]

[16] The light-emitting element according to

[15] , wherein the electron injection layer further contains alkali metal atoms or rare earth metal atoms.

[0046]

[17] A display device comprising the light-emitting element described in any one of [8] to

[16] .

[0047]

[18] A lighting device comprising the light-emitting element according to any one of [8] to

[16] .

[0048]

[19] A photosensitizer comprising the light-emitting element according to any one of [8] to

[16] .

[0049] Effects of the Invention

[0050] According to the present invention, an organic EL element having excellent luminous efficiency and durable life can be provided. DETAILED DESCRIPTION

[0051] Hereinafter, preferred embodiments of the compound, light-emitting element, display device, lighting device, and photosensitizer according to the present invention will be described in detail. However, the present invention is not limited to the following embodiments and can be implemented with various modifications depending on the purpose and application.

[0052] (Compound represented by general formula (1))

[0053] The compound according to the embodiment of the present invention is a compound represented by the general formula (1).

[0054] [Chemical Formula 7]

[0055]

[0056] In the general formula (1), R 1 and R 2 are each independently selected from the group consisting of substituted or unsubstituted aryl and substituted or unsubstituted heteroaryl. 1 and R 2 They can be connected to each other to form a ring structure. 3 is selected from the group consisting of a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heteroaryl group. L is a substituted or unsubstituted arylene group, or a substituted or unsubstituted heteroarylene group. A is a structure represented by the following general formula (2) or (3).

[0057] [Chemical Formula 8]

[0058]

[0059] [Chemical Formula 9]

[0060]

[0061] In general formulas (2) and (3), R 4 ~R 14 are each independently selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heteroaryl group. 4 ~R 11 One of them is directly connected to L, R 12 ~R 14 One of them is directly connected to L. R 7 and R 8 Can be connected to each other to form a ring structure. 1 ~X 8 Each independently represents a carbon atom or a nitrogen atom. 1 and X 2 At least one of X is a nitrogen atom, 3 ~X 8 At least one of them is a nitrogen atom.

[0062] In all the above groups, hydrogen atoms may be deuterium atoms. This also applies to the substituents, compounds, or partial structures described below.

[0063] When referred to as "substituted or unsubstituted", "unsubstituted" means that a hydrogen atom or a deuterium atom is bonded. The same applies to the case where "substituted or unsubstituted" is referred to in the compounds or partial structures described below.

[0064] The aryl group includes, for example, phenyl, biphenyl, terphenyl, naphthyl, fluorenyl, benzofluorenyl, dibenzofluorenyl, phenanthryl, anthracenyl, triphenylenyl, benzanthryl, Aromatic hydrocarbon groups such as phenanthrenyl, pyrenyl, fluoranthenyl, benzo[9,10]phenanthryl (triphenylenyl), benzofluoranthenyl, dibenzanthryl, perylenyl, and spiroenyl are also included. The number of ring atoms is not particularly limited, but is preferably in the range of 6 to 40, and more preferably in the range of 6 to 30. Among these, phenyl is preferred.

[0065] The arylene group includes, for example, phenylene, biphenylene, terphenylene, naphthylene, fluorenylene, benzofluorenylene, dibenzofluorenylene, phenanthrenylene, anthracenylene, triphenylenylene, benzanthrylene, phenyl ... An aromatic hydrocarbon group such as an arylene group, a pyrenyl group, a fluoranthenyl group, a benzo[9,10]phenanthryl group, a benzofluoranthenyl group, a dibenzoanthryl group, a perylene group, or a spiroenyl group. Here, the divalent bonds of the arylene group are connected to the same conjugated system. The number of ring atoms is not particularly limited, but is preferably in the range of 6 to 40, and more preferably in the range of 6 to 30. Among these, phenylene and biphenylene are preferred.

[0066] The so-called heteroaryl group refers to, for example, a cyclic aromatic group having one or more atoms other than carbon in the ring, such as pyridyl, furyl, thienyl, quinolyl, isoquinolyl, pyrazinyl, pyrimidinyl, pyridazinyl, triazinyl, naphthyridinyl, cinnolinyl, phthalazinyl, quinoxalinyl, quinazolinyl, benzofuranyl, benzothienyl, indolyl, dibenzofuranyl, dibenzothienyl, carbazolyl, benzocarbazolyl, carbolyl, indolocarbazolyl, benzofuranocarbazolyl, benzothienocarbazolyl, dihydroindenocarbazolyl, benzoquinolyl, acridinyl, dibenzoacridinyl, benzimidazolyl, imidazopyridyl, benzoxazolyl, benzothiazolyl, and phenanthrolinyl. The naphthyridinyl group refers to any one of 1,5-naphthyridinyl, 1,6-naphthyridinyl, 1,7-naphthyridinyl, 1,8-naphthyridinyl, 2,6-naphthyridinyl, and 2,7-naphthyridinyl. The number of ring atoms is not particularly limited, but is preferably in the range of 5 to 40, and more preferably in the range of 5 to 30.

[0067] The heteroarylene group includes, for example, pyridylene, furylene, thienylene, quinolylene, isoquinolylene, pyrazinylene, pyrimidylene, pyridazinylene, triazinylene, naphthyridylene, cinnolinylene, phthalazinylene, quinoxalinylene, quinazolinylene, benzofuranylene, benzothienylene, indolylene, dibenzofuranylene, dibenzothienylene, carbazolylene, phenylene The cyclic aromatic groups having one or more atoms other than carbon in the ring, such as carbazolyl, carbolyl, indolecarbazolyl, benzofurancarbazolyl, benzothiophenecarbazolyl, indenecarbazolyl, benzoquinolyl, acridinyl, dibenzoacridinyl, benzimidazolyl, imidazopyridinyl, benzoxazolyl, benzothiazolyl, phenanthroline, etc., are represented by. Wherein, the so-called naphthyridinyl group represents any one of 1,5-naphthyridinyl, 1,6-naphthyridinyl, 1,7-naphthyridinyl, 1,8-naphthyridinyl, 2,6-naphthyridinyl and 2,7-naphthyridinyl. Here, the divalent bond of the heteroarylene group is connected to the same conjugated system. The number of ring atoms is not particularly limited, but is preferably in the range of 5 or more and 40 or less, more preferably in the range of 5 or more and 30 or less. Among them, phenylene and biphenylene are preferred.

[0068] The term "alkyl" refers to, for example, saturated aliphatic hydrocarbon groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, and tert-butyl. The number of carbon atoms in the alkyl group is not particularly limited; however, from the perspectives of availability and cost, it is preferably in the range of 1 to 20, and more preferably in the range of 1 to 8. The term "carbon number" herein includes the number of carbon atoms contained in substituents bonded to the alkyl group, and the same applies to other substituents for which the number of carbon atoms is specified.

[0069] The term "alkoxy" refers to a group formed by bonding an alkyl group such as methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, or tert-butoxy to oxygen. The number of carbon atoms in the alkoxy group is not particularly limited; however, from the perspectives of availability and cost, the number is generally preferably 1 to 20, and more preferably 1 to 8.

[0070] As conventional compounds containing nitrogen-containing aromatic heterocycles and polycyclic aromatic hydrocarbons, for example, Patent Documents 1 to 4 disclose compounds W, X, Y, and Z represented by the following formulae.

[0071] [Chemical Formula 10]

[0072]

[0073] However, even when these compounds are used as materials for organic EL devices in electron injection layers, electron transport layers, or charge generation layers, they still do not achieve sufficient performance in terms of the properties required in recent years. Therefore, there is a need for compounds that can further improve performance in terms of luminous efficiency and long life.

[0074] For example, a compound having an imidazophenanthroline skeleton such as Compound W has a molecular weight of 310 and has problems with thermal stability and durability.

[0075] Compounds having a benzoacridine skeleton such as Compound X have high planarity derived from the benzoacridine skeleton, resulting in excessively high crystallinity. This leads to low film stability, high driving voltage, and problems with luminous efficiency and long life.

[0076] Compounds such as Compound Y having an anthracene skeleton and a p-biphenyl skeleton have excessively high crystallinity due to the high planarity of the anthracene skeleton. Furthermore, the molecular weight of the compound is greater than 700, which leads to reduced handleability and film stability.

[0077] Compounds having an arylamine skeleton such as Compound Z have an electron-donating substituent in the molecule, and therefore, there is a problem that the electron transport property of the compound is reduced and the driving voltage is increased.

[0078] The inventors of this application have focused on the effect of the imidazole skeleton in their research on improvement. The imidazole skeleton is a substituent with a large electron transport property and a high coordination property to the metal atom. The compound represented by the general formula (1) has an aryl or heteroaryl group as R 1 and R 2 , which makes it easier to conjugate and the electron transport property becomes greater. 1 and R 2 When they are linked to each other, the ring structure is fixed, thereby further improving the durability of the compound.

[0079] From the perspective of easy availability and operability of the compound, R 1 With R 2 The total number of carbon atoms in is preferably 8 to 20. In addition, from the viewpoint of improving film stability and further improving the durability of the light-emitting element, R 1 and R 2 More preferably, they are each independently selected from the group consisting of phenyl and pyridyl.

[0080] By making R 3 For the purpose of imparting appropriate crystallinity to the compound, R 3The number of carbon atoms in R is preferably 1 to 12. 3 More preferred are methyl and phenyl groups.

[0081] By making L the above-mentioned groups, the groups on both sides of L become more easily conjugated. Therefore, the electron transport property of the compound is further enhanced. From the perspective of having appropriate crystallinity of the compound, improving film stability, and further improving the long-term life of the light-emitting device, L is preferably a phenylene group, a naphthylene group, or a biphenylene group.

[0082] When A is the general formula (2), by making X 1 and X 2 At least one of the nitrogen atoms is a nitrogen atom, thereby improving the electron transport property of the compound. Similarly, when A is the general formula (3), by making X 3 ~X 8 At least one of the atoms is a nitrogen atom, thereby improving the electron transport property of the compound. In particular, when A is represented by any of the general formulae (4) to (6), these layers exhibit more stable and excellent performance, which is more preferred.

[0083] [Chemical Formula 11]

[0084]

[0085] [Chemical Formula 12]

[0086]

[0087] [Chemical Formula 13]

[0088]

[0089] When A is of the general formula (4) to (6), R 4 ~R 10 、R 15 and R 16 Each is independently selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heteroaryl group. 3 ~X 6 Each independently represents a carbon atom or a nitrogen atom. 3 ~X 6 At least one of them is a nitrogen atom. * indicates the position of connection with L.

[0090] General formula (4) and (5) represent bipyridine skeleton and phenanthroline skeleton respectively.These skeletons have both high coordination and high electron transport to metal, therefore, can contribute to the driving voltage reduction and efficiency improvement in light-emitting element. Especially the phenanthroline skeleton that ring structure is fixed can further improve the coordination to metal atom, therefore, can make driving voltage smaller, and further improve luminous efficiency, therefore is more preferred.

[0091] In general formulas (4) and (5), R 5 ~R 10 、R 15 and R 16 Preferably, each is independently selected from the group consisting of a hydrogen atom, a methyl group, and a phenyl group. 5 ~R 10 、R 15 and R 16 More preferably, it is a hydrogen atom.

[0092] In general formulas (4) and (5), R 4 Preferably, it is a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group. In this case, R is bonded to the highly reactive 2-position in the bipyridine skeleton and the phenanthroline skeleton. 4 , thus improving the stability of the compound and the device. 4 More preferably, it is phenyl, pyridyl, fluorophenyl and tolyl. These substituents impart appropriate crystallinity to the compound, thereby forming a stable layer. Therefore, the driving voltage can be further reduced and the durability life can be improved. From the perspective of further improving the stability and durability of the element, R 4 A phenyl group is more preferred.

[0093] The general formula (6) has a 6-membered ring skeleton containing at least one nitrogen atom, and thus, when used as A, it exhibits high coordination and high electron transport properties to metals, thereby achieving a reduction in driving voltage and an improvement in efficiency in light-emitting elements. 3 is a nitrogen atom and X 4 ~X 6 When one of the atoms is a nitrogen atom, the general formula (6) becomes a terpyridine skeleton, which can further improve the coordination with the metal atom. In this case, the driving voltage can be lowered and the luminous efficiency can be further improved, which is more preferable.

[0094] From the perspective of suppressing crystallization and improving film stability, the molecular weight of the compound represented by general formula (1) is preferably 380 or greater. On the other hand, from the perspective of improving sublimation purification and processability during vapor deposition, the molecular weight of the compound represented by general formula (1) is preferably 660 or less.

[0095] Among all the above-mentioned groups, the substituents in the case of substitution are preferably alkyl, cycloalkyl, heteroalicyclic, alkenyl, cycloalkenyl, alkynyl, aryl, heteroaryl, hydroxyl, thiol, alkoxy, alkylthio, aryl ether, aryl thioether, halogen, cyano, aldehyde, acyl, carboxyl, ester, amide, acyl, sulfonyl, sulfonate, sulfonamide, amino, nitro, silyl, siloxane, borane, and oxo. In addition, these substituents may be substituted by the above-mentioned substituents.

[0096] The cycloalkyl group includes, for example, saturated alicyclic hydrocarbon groups such as cyclopropyl, cyclohexyl, norbornyl, and adamantyl, which may or may not have a substituent. The number of ring carbon atoms is not particularly limited, but is preferably in the range of 3 or more and 20 or less.

[0097] The heteroalicyclic group refers to an aliphatic ring having atoms other than carbon in the ring, such as a pyran ring, a piperidine ring, or a cyclic amide, and may or may not have a substituent. The number of ring atoms is not particularly limited, but is preferably in the range of 3 or more and 20 or less.

[0098] The term "alkenyl" refers to an unsaturated aliphatic hydrocarbon group containing a double bond, such as vinyl, allyl, or butadienyl, and may or may not have a substituent. The number of carbon atoms in the alkenyl group is not particularly limited, but is preferably in the range of 2 or more and 20 or less.

[0099] The cycloalkenyl group refers to an unsaturated alicyclic hydrocarbon group containing a double bond, such as a cyclopentenyl group, a cyclopentadienyl group, and a cyclohexenyl group, and may or may not have a substituent.

[0100] The term "alkynyl" refers to an unsaturated aliphatic hydrocarbon group containing a triple bond, such as ethynyl, which may or may not have a substituent. The number of carbon atoms in the alkynyl group is not particularly limited, but is preferably in the range of 2 or more and 20 or less.

[0101] Examples of the compound represented by the general formula (1) include the following compounds. The following are merely examples, and compounds other than those explicitly described herein can also be preferably used as long as they are compounds represented by the general formula (1).

[0102] [Chemical Formula 14]

[0103]

[0104] [Chemical Formula 15]

[0105]

[0106] [Chemical Formula 16]

[0107]

[0108] [Chemical Formula 17]

[0109]

[0110] [Chemical Formula 18]

[0111]

[0112] [Chemical Formula 19]

[0113]

[0114] [Chemical Formula 20]

[0115]

[0116] [Chemical Formula 21]

[0117]

[0118] [Chemical Formula 22]

[0119]

[0120] [Chemical Formula 23]

[0121]

[0122] [Chemical Formula 24]

[0123]

[0124] [Chemical Formula 25]

[0125]

[0126] [Chemical Formula 26]

[0127]

[0128] [Chemical Formula 27]

[0129]

[0130] [Chemical Formula 28]

[0131]

[0132] [Chemical Formula 29]

[0133]

[0134] [Chemical formula 30]

[0135]

[0136] [Chemical Formula 31]

[0137]

[0138] [Chemical Formula 32]

[0139]

[0140] [Chemical Formula 33]

[0141]

[0142] [Chemical Formula 34]

[0143]

[0144] [Chemical Formula 35]

[0145]

[0146] [Chemical Formula 36]

[0147]

[0148] [Chemical Formula 37]

[0149]

[0150] [Chemical Formula 38]

[0151]

[0152] [Chemical Formula 39]

[0153]

[0154] [Chemical Formula 40]

[0155]

[0156] [Chemical Formula 41]

[0157]

[0158] [Chemical Formula 42]

[0159]

[0160] [Chemical Formula 43]

[0161]

[0162] [Chemical Formula 44]

[0163]

[0164] [Chemical Formula 45]

[0165]

[0166] [Chemical Formula 46]

[0167]

[0168] [Chemical Formula 47]

[0169]

[0170] [Chemical Formula 48]

[0171]

[0172] [Chemical Formula 49]

[0173]

[0174] [Chemical Formula 50]

[0175]

[0176] [Chemical Formula 51]

[0177]

[0178] [Chemical Formula 52]

[0179]

[0180] [Chemical Formula 53]

[0181]

[0182] [Chemical Formula 54]

[0183]

[0184] [Chemical Formula 55]

[0185]

[0186] [Chemical Formula 56]

[0187]

[0188] [Chemical Formula 57]

[0189]

[0190] [Chemical Formula 58]

[0191]

[0192] [Chemical Formula 59]

[0193]

[0194] The compound represented by the general formula (1) can be synthesized by a known synthesis method. Examples of the synthesis method include, but are not limited to, the reaction of an aryl aldehyde with 1,2-diketone using ammonium acetate.

[0195] The compound represented by the general formula (1) is preferably used in any layer of a light-emitting element. As described later, the compound represented by the general formula (1) is preferably used in a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, a protective film (cap layer) of an electrode, etc. in a light-emitting element. By using the material represented by the general formula (1) in any layer of a light-emitting element, a light-emitting element with excellent luminous efficiency and long life can be provided.

[0196] (Light-emitting element)

[0197] A light-emitting element comprises an anode, a cathode, and an organic layer interposed between the anode and cathode, and the organic layer emits light using electrical energy. In the following description, such a light-emitting element may be referred to as an "organic EL element."

[0198] As for the layer structure between the anode and the cathode in the organic EL element, in addition to the structure formed by only the light-emitting layer, there are also stacked structures such as 1) light-emitting layer / electron transport layer, 2) hole transport layer / light-emitting layer, 3) hole transport layer / light-emitting layer / electron transport layer, 4) hole injection layer / hole transport layer / light-emitting layer / electron transport layer, 5) hole transport layer / light-emitting layer / electron transport layer / electron injection layer, 6) hole injection layer / hole transport layer / light-emitting layer / electron transport layer / electron injection layer, and 7) hole injection layer / hole transport layer / light-emitting layer / hole blocking layer / electron transport layer / electron injection layer.

[0199] In addition, it can also be a tandem type in which a plurality of the above-mentioned stacked structures are stacked via an intermediate layer. The intermediate layer is generally referred to as an intermediate electrode, an intermediate conductive layer, a charge generating layer, an electron extraction layer, a connecting layer, and an intermediate insulating layer, and can be composed of known materials. Specific examples of the tandem type include, for example, 8) hole transport layer / luminescent layer / electron transport layer / charge generating layer / hole transport layer / luminescent layer / electron transport layer, 9) hole injection layer / hole transport layer / luminescent layer / electron transport layer / electron injection layer / charge generating layer / hole injection layer / hole transport layer / luminescent layer / electron transport layer / electron injection layer, such a stacked structure including a charge generating layer as an intermediate layer between the anode and the cathode.

[0200] In addition, each of the above-mentioned layers can be any of a single layer or a multilayer, and can also be doped. In particular, when the above-mentioned electron injection layer and the charge generation layer are metal-doped layers doped with metal, it is possible to improve the electron transport ability and the electron injection ability into other adjacent layers, and therefore it is preferred. In addition, when a protective layer (capping layer) is provided in addition to the above-mentioned layers, it is possible to further improve the luminous efficiency by utilizing the optical interference effect, and therefore it is preferred.

[0201] The compound represented by the general formula (1) can be used in any of the above-mentioned layers in the organic EL element, but is particularly preferably used in an electron transport layer, a charge generation layer, or an electron injection layer. The organic EL element involved in the embodiment of the present invention is preferably composed of the following: at least an electron transport layer and a light-emitting layer between the anode and the cathode, and the electron transport layer contains a compound represented by the general formula (1); at least a charge generation layer and a light-emitting layer between the anode and the cathode, and the charge generation layer contains a compound represented by the general formula (1); or at least an electron injection layer and a light-emitting layer between the anode and the cathode, and the electron injection layer contains a compound represented by the general formula (1). The material for an organic EL element represented by the general formula (1) may also be contained in two or more of these layers.

[0202] In the organic EL element according to the embodiment of the present invention, the anode and cathode have the function of supplying a current sufficient to cause the element to emit light. In order to extract the light, at least one of them is preferably transparent or translucent. Typically, the anode formed on the substrate is a transparent electrode.

[0203] (Substrate)

[0204] To ensure the mechanical strength of organic EL elements, they are preferably formed on a substrate. Examples of substrates include glass substrates such as soda-lime glass and alkali-free glass, as well as plastic substrates. When using a glass substrate, the thickness should be sufficient to ensure mechanical strength, with a minimum of 0.5 mm being sufficient. The glass material should preferably be low in ion dissolution, with alkali-free glass being preferred. Soda-lime glass coated with a barrier coating such as SiO2 is also commercially available and can also be used.

[0205] (anode)

[0206] An anode is formed on a substrate. The material for the anode is preferably capable of efficiently injecting holes into the organic layer. In addition, in order to extract light, it is preferably transparent or translucent. As the material for the anode, for example, conductive metal oxides such as zinc oxide, tin oxide, indium oxide, indium tin oxide (ITO), indium zinc oxide (IZO), metals such as gold, silver, chromium, inorganic conductive materials such as copper iodide, copper sulfide, conductive polymers such as polythiophene, polypyrrole, polyaniline, etc. can be enumerated. Among them, ITO glass and Nesser glass are preferred. These electrode materials can be used alone, or a variety of materials can be stacked or mixed and used.

[0207] (cathode)

[0208] The material for the cathode is not particularly limited as long as it is a substance that can efficiently inject electrons into the light-emitting layer. As the material for the cathode, for example, metals such as platinum, gold, silver, copper, iron, tin, aluminum, indium, or alloys of these metals with low work function metals such as lithium, sodium, potassium, calcium, magnesium, multilayer stacking, etc. can be cited. Among them, from the aspects of resistance value, ease of film making, stability of the film, luminous efficiency, etc., as the main component, it is preferably a metal selected from the group consisting of aluminum, silver, and magnesium, and from the aspect of easy electron injection into the electron transport layer and the electron injection layer, it is more preferably composed of magnesium and silver.

[0209] (Protective layer)

[0210] In order to protect the cathode, a protective layer (capping layer) is preferably stacked on the cathode. As the material constituting the protective layer (capping material), it is not particularly limited, for example, metals such as platinum, gold, silver, copper, iron, tin, aluminum and indium, inorganic substances such as alloys of these metals, silicon dioxide, titanium dioxide and silicon nitride, organic polymer compounds such as polyvinyl alcohol, polyvinyl chloride, hydrocarbon-based polymer compounds, etc. can be cited. In addition, the compound represented by general formula (1) can also be used as a capping material. However, in the case where the organic EL element is an element structure (top emission structure) that takes out light from the cathode side, the capping material preferably has light transmittance in the visible light region.

[0211] (Hole Injection Layer)

[0212] The hole injection layer is a layer inserted between the anode and the hole transport layer. The hole injection layer can be a single layer or a plurality of layers can be stacked. If a hole injection layer is present between the hole transport layer and the anode, low voltage driving can be further achieved, and the durability life is also improved. In addition, the carrier balance of the device is further improved, and the luminous efficiency is also improved, which is preferred.

[0213] The material for the hole injection layer can use a known material. For example, benzidine derivatives, a material group known as a starburst arylamine, a triarylamine derivative, a biscarbazole derivative, a pyrazoline derivative, a stilbene compound, a fluorene compound, a hydrazone compound, a benzofuran derivative, a thiophene derivative, an oxadiazole derivative, a phthalocyanine derivative, a porphyrin derivative and other heterocyclic compounds, a polycarbonate having the above-mentioned derivatives or compounds on the side chain, a styrene derivative, a polythiophene, a polyaniline, a polyfluorene, a polyvinylcarbazole, a polymer material such as a polysilane, etc. From the viewpoint of smoothly injecting and transporting holes from the anode to the hole transport layer, it is more preferable to use a benzidine derivative, a starburst arylamine material group, and a fluorene compound.

[0214] These materials can be used alone or in combination of two or more materials. In addition, a plurality of materials can be stacked and used as a hole injection layer. In addition, if the hole injection layer is composed of an acceptor compound alone or is doped with an acceptor compound in the hole injection material as described above, the above-mentioned effect can be obtained more significantly, and therefore it is more preferred. The so-called acceptor compound is a material that forms a charge transfer complex with the hole transport layer that is in contact when used as a monolayer film and the hole injection layer when doped. If such a material is used, the conductivity of the hole injection layer is improved, which is more conducive to reducing the driving voltage of the component and can further improve luminous efficiency and durable life.

[0215] As the acceptor compound, known materials can be used. For example, metal oxides such as metal chlorides and molybdenum oxide, charge transfer complexes, organic compounds having a nitro group, a cyano group, a halogen group or a trifluoromethyl group in the molecule, quinone compounds, acid anhydride compounds, fullerenes, etc. can be cited. Among them, metal oxides and cyano-containing compounds are easy to handle and easy to vapor-deposit, so it is easy to obtain the above-mentioned effect, so they are preferred. In any case where the hole injection layer is composed of an acceptor compound alone or in the case where an acceptor compound is doped in the hole injection layer, the hole injection layer can be one layer or a plurality of layers can be stacked and constituted.

[0216] (Hole Transport Layer)

[0217] The hole transport layer is a layer that transports holes injected from the anode to the light-emitting layer. The hole transport layer may be a single layer or a stack of multiple layers.

[0218] Materials used for the hole transport layer include those exemplified as materials for the hole injection layer. From the viewpoint of smoothly injecting and transporting holes into the light-emitting layer, triarylamine derivatives or benzidine derivatives are more preferred.

[0219] (Luminescent layer)

[0220] The light-emitting layer can be any of a single layer and a multilayer. The light-emitting layer is formed of a light-emitting material, and the light-emitting material can be a mixture of a host material and a dopant material, or can be a host material alone, or can be a mixture of two host materials and one dopant material, which can be any of the above. That is, with respect to the organic EL element in the embodiment of the present invention, in each light-emitting layer, only the host material or the dopant material can emit light, or both the host material and the dopant material can emit light. From the viewpoint of efficiently utilizing electrical energy and obtaining light of high color purity, the light-emitting layer preferably contains a mixture of a host material and a dopant material. In addition, the host material and the dopant material can each be one or a combination of multiple materials.

[0221] When the light-emitting layer is formed from a mixture of a host material and a dopant material, the dopant material can be contained in the host material as a whole or locally. The dopant material can be stacked or dispersed. The dopant material can be used to control the color of the emitted light. From the perspective of suppressing concentration quenching, the total amount of the host material and the dopant material is set to 100% by weight, and the amount of the dopant material is preferably 30% by weight or less, and more preferably 20% by weight or less. Regarding the doping method, it can be formed by co-evaporation with the host material, or it can be mixed with the host material in advance and then evaporated simultaneously.

[0222] As the light-emitting material, known materials can be used. For example, fused ring derivatives such as anthracene and pyrene, metal chelated octane compounds such as tris(8-quinolinol)aluminum, bisstyrylanthracene derivatives, bisstyrylbenzene derivatives and other bisstyryl derivatives, tetraphenylbutadiene derivatives, indene derivatives, coumarin derivatives, oxadiazole derivatives, pyrrolopyridine derivatives, perinone derivatives, cyclopentadiene derivatives, thiadiazolopyridine derivatives, dibenzofuran derivatives, carbazole derivatives, indolocarbazole derivatives, polyphenylenevinyl derivatives, polyparaphenylene derivatives, polymers such as polythiophene derivatives, and the like can be cited.

[0223] The host material contained in the luminescent material does not need to be limited to a single compound, and a plurality of compounds may be mixed and used. In addition, a stacked structure may be used. As the host material, known materials may be used. There are no particular restrictions, and examples thereof include naphthalene, anthracene, phenanthrene, pyrene, Compounds having fused aromatic rings such as tetracene, tri-o-phenylene, perylene, fluoranthene, fluorene, and indene, or their derivatives; aromatic amine derivatives such as N,N'-dinaphthyl-N,N'-diphenyl-4,4'-diphenyl-1,1'-diamine; metal chelated octane compounds such as tris(8-quinolinol)aluminum(III); bisstyryl derivatives such as distyrylbenzene derivatives; tetraphenylbutadiene derivatives; indene derivatives; coumarin derivatives; oxadiazole derivatives; pyrrolopyridine derivatives; perinone derivatives; cyclopentadiene derivatives; pyrrolopyrrole derivatives; thiadiazolopyridine derivatives; dibenzofuran derivatives; carbazole derivatives; indolocarbazole derivatives; triazine derivatives; polyphenylenevinyl derivatives; polyparaphenylene derivatives; polyfluorene derivatives; polyvinylcarbazole derivatives; and polymers such as polythiophene derivatives. Among them, as a host material used when the light-emitting layer emits triplet light (phosphorescence), metal chelated octane compounds, dibenzofuran derivatives, dibenzothiophene derivatives, carbazole derivatives, indolocarbazole derivatives, triazine derivatives, tri-o-phenylene derivatives, etc. are preferably used.

[0224] Examples of the dopant material contained in the light-emitting material include compounds having an aryl ring, derivatives thereof, compounds having a heteroaryl ring, derivatives thereof, distyrylbenzene derivatives, aminostyryl derivatives, aromatic acetylene derivatives, tetraphenylbutadiene derivatives, stilbene derivatives, aldazine derivatives, pyrromethene derivatives, diketopyrrolo[3,4-c]pyrrole derivatives, coumarin derivatives, azole derivatives, metal complexes thereof, aromatic amine derivatives, and compounds represented by the following general formula (7). Among these, dopant materials containing a diamine skeleton and a fluoranthene skeleton can further improve the luminous efficiency, and compounds represented by the following general formula (7) can further improve the luminous efficiency and the durable life.

[0225] [Chemical Formula 60]

[0226]

[0227] In the general formula (7), the Za ring, the Zb ring, and the Zc ring are each independently a substituted or unsubstituted aryl ring having 6 to 30 ring carbon atoms or a substituted or unsubstituted heteroaryl ring having 5 to 30 ring atoms. 1 and Z 2 Each is independently an oxygen atom, NRa (a nitrogen atom having a substituent Ra) or a sulfur atom. 1When Ra is NRa, Ra may be bonded to Za ring or Zb ring to form a ring, or may not be bonded to Za ring or Zb ring to form a ring. 2 In the case of NRa, Ra may be bonded to the Zb ring or the Zc ring to form a ring, or may not be bonded to the Zb ring or the Zc ring to form a ring. 1 and Z 2 In the case of NRa, each Ra is independently a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, or a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms. 1 and Z 2 Each of NRa is a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms. In general formula (7), Y is a boron atom, a phosphorus atom, SiRb (a silicon atom having a substituent Rb), P═O, or P═S. Each Rb is independently a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, or a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms. Y is preferably a boron atom. Among all the above-mentioned groups, the substituents in the case of substitution are preferably alkyl, cycloalkyl, heteroalicyclic, alkenyl, cycloalkenyl, alkynyl, aryl, heteroaryl, hydroxyl, thiol, alkoxy, alkylthio, aryl ether, aryl thioether, halogen, cyano, aldehyde, acyl, carboxyl, ester, amide, acyl, sulfonyl, sulfonate, sulfonamide, amino, nitro, silyl, siloxane, borane, and oxo. In addition, these substituents may be substituted by the above-mentioned substituents.

[0228] Examples of the alkyl group, alkoxy group, aryl group, and heteroaryl group include those exemplified as the substituents in the general formula (1).

[0229] The cycloalkyl group includes, for example, saturated alicyclic hydrocarbon groups such as cyclopropyl, cyclohexyl, norbornyl, and adamantyl, which may or may not have a substituent. The number of ring carbon atoms is not particularly limited, but is preferably in the range of 3 or more and 20 or less.

[0230] The heteroalicyclic group refers to an aliphatic ring having atoms other than carbon in the ring, such as a pyran ring, a piperidine ring, or a cyclic amide, and may or may not have a substituent. The number of ring atoms is not particularly limited, but is preferably in the range of 3 or more and 20 or less.

[0231] The term "alkenyl" refers to an unsaturated aliphatic hydrocarbon group containing a double bond, such as vinyl, allyl, or butadienyl, and may or may not have a substituent. The number of carbon atoms in the alkenyl group is not particularly limited, but is preferably in the range of 2 or more and 20 or less.

[0232] The cycloalkenyl group refers to an unsaturated alicyclic hydrocarbon group containing a double bond, such as a cyclopentenyl group, a cyclopentadienyl group, and a cyclohexenyl group, and may or may not have a substituent.

[0233] The term "alkynyl" refers to an unsaturated aliphatic hydrocarbon group containing a triple bond, such as ethynyl, which may or may not have a substituent. The number of carbon atoms in the alkynyl group is not particularly limited, but is preferably in the range of 2 or more and 20 or less.

[0234] An alkylthio group is a group obtained by replacing the oxygen atom in the ether bond of an alkoxy group with a sulfur atom. An alkylthio group may or may not have a substituent. The number of carbon atoms in an alkylthio group is not particularly limited, but is preferably in the range of 1 to 20.

[0235] The aryl ether group refers to a functional group in which an aromatic hydrocarbon group is bonded via an ether bond, such as a phenoxy group, and may or may not have a substituent. The number of carbon atoms in the aryl ether group is not particularly limited, but is preferably in the range of 6 or more and 40 or less.

[0236] The aryl thioether group is a functional group obtained by replacing the oxygen atom in the ether bond of an aryl ether group with a sulfur atom, and may or may not have a substituent. The number of carbon atoms in the aryl thioether group is not particularly limited, but is preferably in the range of 6 or more and 40 or less.

[0237] The halogen refers to fluorine, chlorine, bromine or iodine.

[0238] The term "acyl group" refers to a functional group such as acetyl, propionyl, benzoyl, or acryloyl, which is bonded to an alkyl, cycloalkyl, alkenyl, alkynyl, aryl, or heteroaryl group through a carbonyl group. The acyl group may or may not have a substituent. The number of carbon atoms in the acyl group is not particularly limited, but is preferably 2 or more and 40 or less, and more preferably 2 or more and 30 or less.

[0239] The so-called ester group, for example, represents a functional group obtained by bonding via an ester bond such as an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group, and may or may not have a substituent. The number of carbon atoms in the ester group is not particularly limited, but is preferably in the range of 1 to 20. More specifically, methyl ester groups such as methoxycarbonyl, ethyl ester groups such as ethoxycarbonyl, propyl ester groups such as propoxycarbonyl, butyl ester groups such as butoxycarbonyl, isopropyl ester groups such as isopropoxymethoxycarbonyl, hexyl ester groups such as hexyloxycarbonyl, phenyl ester groups such as phenoxycarbonyl, etc. can be mentioned.

[0240] The so-called amide group refers to a functional group formed by bonding an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group, etc. through an amide bond, and may or may not have a substituent. The number of carbon atoms in the amide group is not particularly limited, but is preferably in the range of 1 to 20. More specifically, methylamide group, ethylamide group, propylamide group, butylamide group, isopropylamide group, hexylamide group, phenylamide group, etc. can be mentioned.

[0241] The sulfonyl group refers to a functional group formed by bonding an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group, or the like through a -S(=O)2- bond, and may or may not have a substituent. The number of carbon atoms in the sulfonyl group is not particularly limited, but is preferably within the range of 1 to 20.

[0242] The so-called sulfonate group refers to a functional group formed by bonding an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group, or the like through a sulfonate bond, and may or may not have a substituent. Here, the so-called sulfonate bond refers to a bond formed by replacing the carbonyl portion of the ester bond, i.e., -C(=O)-, with a sulfonyl portion, i.e., -S(=O)2-. The number of carbon atoms in the sulfonate group is not particularly limited, but is preferably in the range of 1 to 20.

[0243] The so-called sulfonamide group refers to a functional group formed by bonding an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group, etc. through a sulfonamide bond, and may or may not have a substituent. Here, the so-called sulfonamide bond refers to a bond formed by replacing the carbonyl portion of the amide bond, i.e., -C(=O)-, with a sulfonyl portion, i.e., -S(=O)2-. The number of carbon atoms in the sulfonamide group is not particularly limited, but is preferably in the range of 1 to 20.

[0244] The amino group may or may not have a substituent. The number of carbon atoms in the amino group is not particularly limited, but is preferably in the range of 2 to 50, more preferably in the range of 6 to 40, and particularly preferably in the range of 6 to 30.

[0245] The term "silyl group" refers to a functional group bonded to a substituted or unsubstituted silicon atom, and includes, for example, alkylsilyl groups such as trimethylsilyl, triethylsilyl, tert-butyldimethylsilyl, propyldimethylsilyl, and vinyldimethylsilyl, and arylsilyl groups such as phenyldimethylsilyl, tert-butyldiphenylsilyl, triphenylsilyl, and trinaphthylsilyl. The silyl group may or may not have a substituent. The number of carbon atoms in the silyl group is not particularly limited, but is preferably in the range of 1 to 30.

[0246] The term "siloxane group" refers to a silicon compound group formed via an ether bond, such as a trimethylsiloxane group, etc. The siloxane group may or may not have a substituent.

[0247] The borane group may or may not have a substituent.

[0248] Examples of the compound represented by the general formula (7) include the following.

[0249] [Chemical Formula 61]

[0250]

[0251] In the organic EL device according to the embodiment of the present invention, it is also preferred that the light-emitting layer contain a triplet light-emitting material.

[0252] The dopant material used when the light-emitting layer emits triplet light (phosphorescence) is preferably a metal complex containing at least one metal selected from the group consisting of iridium (Ir), ruthenium (Ru), palladium (Pd), platinum (Pt), osmium (Os), and rhenium (Re). The ligand constituting the metal complex preferably has a nitrogen-containing aromatic heterocycle such as a phenylpyridine skeleton, a phenylquinoline skeleton, or a carbene skeleton. However, this is not a limitation; the appropriate complex can be selected based on the desired emission color, device performance, and relationship with the host material. Specifically, there can be mentioned tris(2-phenylpyridyl)iridium complex, tris{2-(2-thienyl)pyridyl}iridium complex, tris{2-(2-benzothienyl)pyridyl}iridium complex, tris(2-phenylbenzothiazole)iridium complex, tris(2-phenylbenzoxazole)iridium complex, tribenzoquinolineiridium complex, bis(2-phenylpyridyl)(acetylacetonate)iridium complex, bis{2-(2-thienyl)pyridyl}iridium complex, bis{2-(2-benzothienyl)pyridyl}(acetylacetonate)iridium complex, bis(2-phenylbenzothiazole)(acetylacetonate)iridium complex Complex, bis(2-phenylbenzoxazole)(acetylacetone)iridium complex, dibenzoquinoline(acetylacetone)iridium complex, bis{2-(2,4-difluorophenyl)pyridyl}(acetylacetone)iridium complex, tetraethylporphyrin platinum complex, {tris(thienyltrifluoroacetone)mono(1,10-phenanthroline)}europium complex, {tris(thienyltrifluoroacetone)mono(4,7-diphenyl-1,10-phenanthroline)}europium complex, {tris(1,3-diphenyl-1,3-propanedione)mono(1,10-phenanthroline)}europium complex, trisacetylacetonate terbium complex, etc. In addition, the phosphorescent dopant material described in Japanese Patent Application Laid-Open No. 2009-130141 is also preferably used. Iridium complex or platinum complex is preferred, and can further improve the luminous efficiency.

[0253] The triplet light-emitting materials used as dopant materials may be included in the light-emitting layer alone or in a mixture of two or more. When two or more triplet light-emitting materials are used, the total weight of the dopant materials relative to the host material is preferably 30% by weight or less, and more preferably 20% by weight or less.

[0254] Preferred host materials and dopant materials in a triplet light-emitting system are not particularly limited, but specific examples include the following.

[0255] [Chemical Formula 62]

[0256]

[0257] [Chemical Formula 63]

[0258]

[0259] In addition, it is also preferred that the light-emitting layer contains a thermally activated delayed fluorescence material. Thermally activated delayed fluorescence is explained on pages 87 to 103 of "The Most Advanced Organic EL" (edited by Chiba Ya Andachi and Hiroshi Fujimoto, published by CMC Publishing). In this document, it is explained as follows: By making the energy levels of the excited singlet state and the excited triplet state of the fluorescent material close, reverse energy transfer from the excited triplet state, which usually has a low transition probability, to the excited singlet state is generated with high efficiency, resulting in thermally activated delayed fluorescence (TADF). In addition, Figure 5 in this document illustrates the generation mechanism of delayed fluorescence. The luminescence of delayed fluorescence can be confirmed by transition PL (PhotoLuminescence) measurement.

[0260] Thermally activated delayed fluorescence materials are also commonly referred to as TADF materials. A thermally activated delayed fluorescence material can be a material that exhibits thermally activated delayed fluorescence with a single material, or a material that exhibits thermally activated delayed fluorescence with a plurality of materials. When the material is composed of a plurality of materials, it can be used as a mixture, or layers formed by stacking the materials can be used. As a thermally activated delayed fluorescence material, known materials can be used. For example, benzonitrile derivatives, triazine derivatives, disulfoxide derivatives, carbazole derivatives, indolocarbazole derivatives, dihydrophenazine derivatives, thiazole derivatives, oxadiazole derivatives, etc. can be mentioned, but are not limited thereto.

[0261] In devices containing a TADF material in the light-emitting layer, it is preferable to further include a fluorescent dopant material in the light-emitting layer. This is because the TADF material converts triplet excitons into singlet excitons, which are then absorbed by the fluorescent dopant material, thereby achieving higher luminous efficiency and a longer lifespan.

[0262] (Electron Transport Layer)

[0263] In the present invention, the so-called electron transport layer is a layer that further transports electrons after injecting electrons from the cathode. For the electron transport layer, it is desired that the electron injection efficiency is high and the injected electrons are transported efficiently. Therefore, the material constituting the electron transport layer is preferably a substance having a large electron affinity, a large electron mobility, excellent stability, and not prone to producing impurities that become traps during manufacture and use. Especially when the film thickness is stacked thickly, low molecular weight compounds will crystallize, etc., and the film quality is easily deteriorated. Therefore, in order to ensure a stable film quality, a compound with a molecular weight of 380 or more is preferred. However, considering the transport balance of holes and electrons, as long as the electron transport layer mainly plays a role in efficiently preventing holes from the anode from recombining and flowing to the cathode side, even if it is composed of a material that is not so high in electron transport ability, the effect of improving the luminous efficiency is equivalent to that of a material that is composed of a material with high electron transport ability. Therefore, in the electron transport layer in the present invention, a hole blocking layer that can efficiently prevent holes from moving is also included as a synonymous layer. The hole-blocking layer and the electron-transporting layer may be composed of a single material or a stack of multiple materials.

[0264] As an electron transport material for an electron transport layer, known materials can be used. For example, various metal complexes such as fused polycyclic aromatic derivatives, styryl aromatic ring derivatives, quinone derivatives, phosphorus oxide derivatives, hydroxyquinoline complexes, benzohydroxyquinoline complexes, hydroxyazole complexes, azomethine complexes, tropone metal complexes and flavonol metal complexes can be cited. From the perspective of further reducing the driving voltage and obtaining more efficient luminescence, it is preferred to use a compound composed of an element selected from carbon, hydrogen, nitrogen, oxygen, silicon, and phosphorus, and having a heteroaryl ring structure containing electron-accepting nitrogen.

[0265] Here, the so-called electron-accepting nitrogen refers to a nitrogen atom that forms a multiple bond with an adjacent atom. Since nitrogen atoms have high electronegativity, the multiple bond has an electron-accepting property. Therefore, the aromatic heterocycle containing electron-accepting nitrogen has a high electron affinity. The electron transport material with electron-accepting nitrogen easily receives electrons from a cathode with a high electron affinity, enabling driving at a lower voltage. In addition, the electron supply to the light-emitting layer increases, and the recombination probability increases, thereby further improving the luminous efficiency.

[0266] Examples of the heteroaryl ring containing electron-accepting nitrogen include a triazine ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a quinoline ring, a quinoxaline ring, a quinazoline ring, a naphthyridine ring, a pyrimidopyrimidine ring, a benzoquinoline ring, a phenanthroline ring, an imidazole ring, an oxazole ring, an oxadiazole ring, a triazole ring, a thiazole ring, a thiadiazole ring, a benzoxazole ring, a benzothiazole ring, a benzimidazole ring, and a phenanthroimidazole ring.

[0267] Examples of compounds having such heteroaryl ring structures include pyridine derivatives, triazine derivatives, quinazoline derivatives, pyrimidine derivatives, benzimidazole derivatives, benzoxazole derivatives, benzothiazole derivatives, oxadiazole derivatives, thiadiazole derivatives, triazole derivatives, pyrazine derivatives, phenanthroline derivatives, quinoxaline derivatives, quinoline derivatives, benzoquinoline derivatives, oligopyridine derivatives, quinoxaline derivatives, and naphthyridine derivatives. Among these, from the viewpoint of electron transport ability, imidazole derivatives, oxadiazole derivatives, triazole derivatives, triazine derivatives, pyrimidine derivatives, phenanthroline derivatives, benzoquinoline derivatives, bipyridine derivatives, terpyridine derivatives, and naphthyridine derivatives are preferably used.

[0268] In addition, if these derivatives have fused polycyclic aromatic skeletons, then the glass transition temperature is improved, and the electron mobility is also increased, and the driving voltage of the organic EL device can be further reduced, so it is preferred. In addition, considering that the durable life of the device is further improved, the ease of synthesis, the easy acquisition of raw materials, the fused polycyclic aromatic skeleton is more preferably a fluoranthene skeleton, anthracene skeleton, pyrene skeleton or phenanthroline skeleton.

[0269] Preferred electron transport materials are not particularly limited, but specific examples include the following.

[0270] [Chemical Formula 64]

[0271]

[0272] [Chemical Formula 65]

[0273]

[0274] Furthermore, the compound represented by the general formula (1) also has a high electron-transporting property and exhibits excellent properties as an electron-transporting layer, and therefore is preferred.

[0275] The electron transporting material may be used alone, or two or more of them may be mixed and used, or one or more other electron transporting materials may be mixed with the electron transporting material.

[0276] The electron transport layer may also contain a donor material. Here, the donor material is a compound that improves the electron injection barrier to facilitate electron injection from the cathode or the electron injection layer into the electron transport layer, thereby further improving the conductivity of the electron transport layer.

[0277] As the donor material, from the viewpoint of having a low work function and improving electron transport properties, it is preferred to contain an alkali metal atom, an alkaline earth metal atom or a rare earth metal atom. Among them, from the viewpoint of being able to further reduce the driving voltage of the organic EL, it is more preferred to contain an alkali metal atom or a rare earth metal atom.

[0278] (Electron Injection Layer)

[0279] In the present invention, an electron injection layer may be provided between the cathode and the electron transport layer. Typically, the electron injection layer is inserted for the purpose of assisting electron injection from the cathode into the electron transport layer. In the case of insertion, a compound having a heteroaryl ring structure containing electron-accepting nitrogen may be used, or a layer containing the above-mentioned donor material may be used.

[0280] In addition, inorganic substances such as insulators and semiconductors can also be used in the electron injection layer. When inorganic substances such as insulators and semiconductors are used in the electron injection layer, they can be selected from known materials. By using these materials, the short circuit of the organic EL element can be suppressed and the electron injectability can be improved.

[0281] As such an insulator, at least one metal compound selected from the group consisting of alkali metal chalcogenides, alkaline earth metal chalcogenides, alkali metal halides, and alkaline earth metal halides is preferred.

[0282] In addition, it is also preferred to use a complex compound of an organic substance and a metal. When using a complex compound of an organic substance and a metal in the electron injection layer, it is possible to easily adjust film thickness. As a preferred example of the organic substance in the organometallic complex, hydroxyquinoline, benzohydroxyquinoline, pyridylphenol, flavonol, hydroxyimidazopyridine, hydroxybenzoxazole, hydroxytriazole etc. can be enumerated.

[0283] In addition, the layer comprising the compound represented by general formula (1) also has high electron injection, showing excellent properties as an electron injection layer, and is therefore preferred. In addition, the electron injection layer preferably contains a compound represented by general formula (1) and an alkali metal atom or a rare earth metal atom. In this case, the driving voltage can be further reduced, and the durable life can be further improved.

[0284] (Charge Generation Layer)

[0285] The charge generation layer in the present invention is usually formed by a double layer. Specifically, it is preferred to use a pn junction charge generation layer formed by an n-type charge generation layer and a p-type charge generation layer. As for the above-mentioned pn junction charge generation layer, by applying a voltage in the organic EL element, charges are generated, or charges are separated into holes and electrons, and these holes and electrons are injected into the light-emitting layer via the hole transport layer and the electron transport layer. The specific use of the charge generation layer is: in an organic EL element having a plurality of light-emitting layers stacked, it is arranged in the middle of the plurality of light-emitting layers and used as a layer responsible for generating charges. The n-type charge generation layer supplies electrons to the first light-emitting layer present on the anode side, and the p-type charge generation layer supplies holes to the second light-emitting layer present on the cathode side. Therefore, the luminous efficiency in the organic EL element formed by stacking a plurality of light-emitting layers can be further improved to reduce the driving voltage, and the durable life of the element can also be further improved.

[0286] The n-type charge generation layer is formed by an n-type dopant material and a host material, and conventional materials can be used. For example, as the n-type dopant material, an alkali metal, an alkaline earth metal or a rare earth metal can be used. In addition, as the host material, a compound having a nitrogen-containing aromatic heterocycle such as a phenanthroline derivative and an oligopyridine derivative can be used. In particular, the compound represented by the general formula (1) or the phenanthroline dimer exhibits excellent properties as the host material of the above-mentioned n-type charge generation layer and is therefore preferred.

[0287] As one embodiment of the charge generating layer, it is preferable to contain a phenanthroline derivative in addition to the compound represented by the general formula (1). Examples of the phenanthroline derivative include the following compounds.

[0288] [Chemical Formula 66]

[0289]

[0290] As one embodiment of the charge generation layer, it is preferred that the charge generation layer further contain an alkali metal atom, a copper group atom, or a rare earth metal atom in addition to the compound represented by general formula (1). Li is particularly preferred as the alkali metal atom. Ag is particularly preferred as the copper group atom. Yb is particularly preferred as the rare earth metal atom.

[0291] As one embodiment of the charge generating layer, a structure containing, in addition to the compound represented by the general formula (1), a phenanthroline derivative and an alkali metal atom, a copper group atom, or a rare earth metal atom is also preferred.

[0292] The p-type charge generation layer is formed from a p-type dopant material and a host material. Conventional materials can be used for these materials. For example, the p-type dopant material can include tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ), tetracyanoquinodimethane derivatives, radialene derivatives, iodine, FeCl3, FeF3, SbCl5, and the like. A radialene derivative is preferred as the p-type dopant material. An arylamine derivative is preferred as the host material.

[0293] The method for forming the above-mentioned layers constituting the organic EL element is not particularly limited to resistance heating evaporation, electron beam evaporation, sputtering, molecular lamination, coating, etc. Generally, resistance heating evaporation or electron beam evaporation is preferred from the perspective of element characteristics.

[0294] The combined thickness of the organic layers between the anode and cathode is not limited, as it depends on the resistance of the light-emitting material, but is preferably 1 to 1000 nm. The thickness of the light-emitting layer, electron transport layer, and hole transport layer is preferably 1 nm to 200 nm, and more preferably 5 nm to 100 nm.

[0295] The organic EL elements according to embodiments of the present invention have the function of converting electrical energy into light. While direct current is primarily used as the electrical energy, pulsed current or alternating current may also be used. While there are no particular restrictions on the current and voltage values, they should be selected to achieve maximum brightness using the lowest possible energy, taking into account the device's power consumption and lifespan.

[0296] The organic EL element according to the embodiment of the present invention is preferably used in the form of a display device such as a display that performs display in a matrix and / or segment system.

[0297] The organic EL elements according to the embodiments of the present invention are also preferably used as backlights for various devices. Backlights are primarily used to improve the visibility of non-self-luminous display devices such as displays, and are used in liquid crystal displays, clocks, audio equipment, automotive panels, display boards, and signage. In particular, the organic EL elements of the present invention are preferably used as backlights for liquid crystal displays, particularly personal computers, for which thinning is being studied, and can provide backlights that are thinner and lighter than conventional backlights.

[0298] The organic EL elements according to the embodiments of the present invention are also preferably used in various lighting devices. The organic EL elements according to the embodiments of the present invention can simultaneously achieve high luminous efficiency and high color purity, while also being thinner and lighter. Therefore, they can realize lighting devices that combine low power consumption with vibrant luminous colors and high design appeal.

[0299] The organic EL elements involved in embodiments of the present invention are also preferably used in the form of photosensitizers. Photosensitizers can be used as a method of photodynamic therapy, which utilizes the fact that reactive oxygen species generated by specific photosensitizers can transform target substances present in biological tissues. Organic EL elements can efficiently generate light from electrodes embedded in the body, and can also achieve efficient generation of reactive oxygen species deep within the body.

[0300] Example

[0301] Hereinafter, the present invention will be described with reference to Examples, but the present invention is not limited to these Examples.

[0302] Synthesis Example 1: Synthesis of Compound 1

[0303] Compound 1 was synthesized by the synthetic route shown below.

[0304] [Chemical Formula 67]

[0305]

[0306] A mixed solution of 6.0 g of raw material A, 3.5 g of benzyl, 25.7 g of ammonium acetate, and 100 ml of acetic acid was heated and stirred at 80°C for 2 hours under a nitrogen stream. After cooling to room temperature, water was added, the mixture was filtered, washed with methanol, and vacuum-dried to obtain 8.6 g of intermediate A.

[0307] Next, a mixed solution of 6.0 g of Intermediate A, 8.9 g of cesium carbonate, 2.3 g of methyl iodide, and 110 ml of DMF was heated and stirred at 80°C for 2 hours under a nitrogen stream. After cooling to room temperature, water was added, the mixture was filtered, and washed with methanol. The mixture was recrystallized from pyridine and dried in vacuo to obtain 5.1 g of Compound 1.

[0308] For the obtained compound 1, an oil diffusion pump was used at 1×10 -3 Sublimation purification was performed at about 330° C. under a pressure of 1.0 Pa. The HPLC purity (area % at a measurement wavelength of 254 nm) of Compound 1 before and after sublimation purification was 99.9%.

[0309] After sublimation and purification, the 1 The structure of Compound 1 was identified by H-NMR analysis. The analysis results are shown below.

[0310] MS (m / z): 565 [M+H] +

[0311] 1H-NMR (400MHz, CDCl3) δ: 9.09 (s, 1H), 8.54-8.65 (m, 4H), 8.45-8.48 (m, 2H), 8.40-8.42 (m, 1H), 8.00- 8.05 (m, 3H), 7.81-7.85 (m, 1H), 7.48-7.63 (m, 7H), 7.40-7.45 (m, 3H), 7.15-7.27 (m, 3H), 3.70 (s, 3H).

[0312] Synthesis Example 2: Synthesis of Compound 9

[0313] Compound 9 was synthesized by the synthetic route shown below.

[0314] [Chemical Formula 68]

[0315]

[0316] Under a nitrogen stream, a mixed solution of 3.7 g of 3-bromobenzaldehyde, 4.2 g of 9,10-phenanthrenequinone, 31.8 g of ammonium acetate, and 100 ml of acetic acid was heated and stirred at 80°C for 2 hours. After cooling to room temperature, water was added, the mixture was filtered, washed with methanol, and vacuum dried. The resulting solid was heated and stirred at 80°C for 2 hours under a nitrogen stream with a mixed solution of 8.9 g of cesium carbonate, 2.3 g of methyl iodide, and 110 ml of DMF. After cooling to room temperature, water was added, the mixture was filtered, and vacuum dried to obtain 6.9 g of intermediate B.

[0317] Next, a mixed solution of 6.9 g of Intermediate B, 6.3 g of bis(pinacolato)diboron, 5.2 g of potassium acetate, 260 mg of bis(diphenylphosphino)ferrocenepalladium dichloride, and 120 ml of dimethylformamide was heated and stirred at 100°C under a nitrogen stream for 3 hours. After cooling to room temperature, water was added, the mixture was filtered, washed with methanol, and vacuum dried to obtain 16.8 g of Intermediate C.

[0318] Next, under a nitrogen stream, a mixed solution of 4.4 g of intermediate C, 2.6 g of 4'-chloro-2,2':6',2"-terpyridine, 4.2 g of tripotassium phosphate, 240 mg of dichlorobis(triphenylphosphine palladium) dichloride, 50 ml of dioxane, and 10 ml of water was heated and stirred under reflux for 8 hours. After cooling to room temperature, water was added and the mixture was filtered, washed with methanol, and vacuum dried. The resulting solid was removed from the catalyst using activated carbon, the solvent was removed by evaporation, and the resulting solid was recrystallized using pyridine and then vacuum dried to obtain 4.0 g of compound 9.

[0319] For the obtained compound 9, an oil diffusion pump was used at 1×10-3 Sublimation purification was performed at about 340° C. under a pressure of 1.5 Pa. The HPLC purity (area % at a measurement wavelength of 254 nm) of Compound 9 before and after sublimation purification was 99.9%.

[0320] After sublimation and purification, the 1 The structure of compound 9 was identified by H-NMR analysis. The analysis results are shown below.

[0321] MS (m / z): 540 [M+H] +

[0322] 1 H-NMR (400MHz, CDCl3) δ: 8.98-9.02 (m, 1H), 8.85-8.91 (m, 3H), 8.78-8.80 (m, 2H), 8.71-8.8.74 (m, 2H), 8.64-8.68 (m, 2H), 8. 38-8.40 (m, 1H), 8.15-8.18 (m, 1H), 8.05-8.09 (m, 3H), 7.85-7.89 (m, 1H), 7.65-7.80 (m, 4H), 7.55-7.58 (m, 2H), 4.38 (s, 3H).

[0323] Synthesis Example 3: Synthesis of Compound 10

[0324] Intermediate C was synthesized in the same manner as in Synthesis Example 2, and then Compound 10 was synthesized through the following synthetic route.

[0325] [Chemical Formula 69]

[0326]

[0327] Under a nitrogen flow, a mixed solution of 3.2 g of intermediate C, 5.6 g of 4'-chloro-2,2':6',2"-terpyridine, 5.0 g of tripotassium phosphate, 150 mg of dichlorobis(triphenylphosphine palladium) dichloride, 60 ml of dioxane, and 10 ml of water was heated and stirred under reflux for 8 hours. After cooling to room temperature, water was added and the mixture was filtered, washed with methanol, and vacuum dried. The resulting solid was removed from the catalyst using activated carbon, and the solvent was removed by evaporation. The resulting solid was recrystallized using pyridine and then vacuum dried to obtain 2.8 g of compound 10.

[0328] For the obtained compound 10, an oil diffusion pump was used at 1×10 -3Sublimation purification was performed at about 340° C. under a pressure of 1.5 Pa. The HPLC purity (area % at a measurement wavelength of 254 nm) of Compound 10 before and after sublimation purification was 99.9%.

[0329] After sublimation and purification, the 1 H-NMR analysis was used to identify the structure of Compound 10. The analysis results are shown below.

[0330] MS (m / z): 539 [M+H] +

[0331] 1 H-NMR (400MHz, CDCl3) δ: 8.98-9.02 (m, 1H), 8.86-8.91 (m, 1H), 8.72-8.75 (m, 1H), 8.58-8.65 (m, 4H), 8.38-8.41 (m, 1H), 8.28-8.34 (m , 2H), 8.23-8.26(m, 1H), 7.98-8.09(m, 3H), 7.92-7.95(m, 1H), 7.65-7.80(m, 5H), 7.48-7.52(m, 1H), 7.14-7.25(m, 2H), 4.40(s, 3H).

[0332] Next, the evaluation method in each example will be described. Unless otherwise specified, the number n in the measurement is 1.

[0333] (Drive voltage)

[0334] Case of single charged element

[0335] 10mA / cm 2 The single charge elements obtained in Examples 1 to 25 and Comparative Examples 1 to 12 were DC driven and the initial drive voltage was measured. Furthermore, the single charge elements were DC driven at 10 mA / cm2 in an environment at a temperature of 70°C. 2 The voltage during direct current driving was measured at a current density of 100 for 100 hours, and the voltage increase relative to the initial driving voltage was calculated.

[0336] ・Organic EL elements

[0337] 1000cd / m 2 The organic EL devices obtained in Examples 26 to 75 and Comparative Examples 13 to 36 were illuminated to a brightness of 10 mA / cm and the initial driving voltage was measured. 2 The voltage during constant current driving was measured at a current density of 100 for 100 hours, and the voltage increase relative to the initial driving voltage was calculated.

[0338] Evaluation of measured values

[0339] The lower the initial driving voltage, the lower the voltage can be used for driving, and thus the luminous efficiency (brightness / power) can be evaluated as being excellent. In addition, the smaller the voltage rise, the better the durable life can be evaluated.

[0340] (External quantum efficiency)

[0341] 10mA / cm 2 The organic EL elements obtained in Examples 26 to 75 and Comparative Examples 13 to 36 were illuminated at a current density of 100 nm and 100 nm, and the external quantum efficiency was measured to evaluate the luminous efficiency. A higher external quantum efficiency indicates better luminous efficiency. A spectroradiometer (manufactured by Konica Minolta Co., Ltd.) was used for the external quantum efficiency measurement.

[0342] (Durability)

[0343] At 10mA / cm 2 The organic EL devices obtained in Examples 26 to 75 and Comparative Examples 13 to 36 were continuously driven at a constant current of 100 Å, and the time required for the luminance to decrease by 20% relative to the initial luminance was measured as the durability.

[0344] Example 1

[0345] A glass substrate (manufactured by Geomatec, 11Ω / □, sputtered) with a 125nm thick ITO transparent conductive film deposited as an anode was cut into 38mm×46mm pieces and etched. The obtained substrate was ultrasonically cleaned for 15 minutes using "Semico Clean" (registered trademark) 56 (trade name, manufactured by Furuuchi Chemical Co., Ltd.) and then washed with ultrapure water. This substrate was subjected to UV-ozone treatment for 1 hour immediately before the production of a single-charge element, and then placed in a vacuum deposition apparatus and evacuated until the vacuum level in the apparatus reached 5×10 -4 Pa or less. Using the resistance heating method, compound 1 and the metal element Yb as a dopant material were evaporated at a deposition rate ratio of compound 1:Yb=9:1 for 100 nm to form an organic layer with a weight ratio of 9:1. Then, 60 nm of aluminum was evaporated to form a cathode, and a single-charge element of 5 mm × 5 mm square was made. The film thickness here refers to the value displayed by a quartz oscillator film thickness monitor, which is the same in other embodiments and comparative examples. The charge generation efficiency and electron transport properties of the compound when evaporated together with the metal can be evaluated using a single-charge element.

[0346] This single-charge element was evaluated by the aforementioned method. As a result, the initial driving voltage was 0.071 V, and the voltage rise amount after driving at 70° C. for 100 hours was 0.022 V.

[0347] Examples 2 to 25, Comparative Examples 1 to 12

[0348] A single-charge element was produced in the same manner as in Example 1, except that the compound, metal element, and the vapor deposition rate ratio of the compound to the metal element were changed as shown in Table 1. The results of each example and comparative example are shown in Table 1. Compounds 1 to 16 are the following compounds.

[0349] Compounds other than Compounds 1, 9, and 10 were synthesized by appropriately changing the starting materials, etc. In addition, Compound 13 was a commercially available product.

[0350] [Chemical Formula 70]

[0351]

[0352] [Chemical Formula 71]

[0353]

[0354] [Table 1]

[0355] [Table 1]

[0356]

[0357] Example 26

[0358] A glass substrate (Geomatec (co., Ltd., 11Ω / □, sputtered product) with a 165nm ITO transparent conductive film deposited as an anode was cut into 38mm×46mm and etched. The obtained substrate was ultrasonically cleaned for 15 minutes using "Semico Clean" 56 (trade name, Furuuchi Chemical (co., Ltd.) and then washed with ultrapure water. This substrate was subjected to UV-ozone treatment for 1 hour just before the production of the organic EL element, and was placed in a vacuum evaporation device and evacuated until the vacuum degree in the device reached 5×10 -4Pa or less. Using the resistance heating method, 5 nm of p-D1 is first evaporated as a hole injection layer, and then 50 nm of HT-1 is evaporated as a hole transport layer. Next, as a light-emitting layer, a mixed layer of the main material H-1 and the dopant material D-1 is evaporated to a thickness of 20 nm in a manner that the doping concentration becomes 5 wt%. Next, as an electron transport layer, ET-1 and 2E-1 are evaporated to a thickness of 35 nm at a deposition rate ratio of ET-1:2E-1=1:1. Next, as an electron injection layer, compound 1 and the metal element Yb as a dopant material are evaporated to 10 nm at a deposition rate ratio of compound 1:Yb=9:1. Then, 60 nm of aluminum is evaporated to form a cathode, and a 5 mm × 5 mm square organic EL element is produced.

[0359] This organic EL element was evaluated by the aforementioned method. The results showed an initial driving voltage of 4.40 V, an external quantum efficiency (luminous efficiency) of 5.39%, a durable life of 1030 hours, and a voltage rise of 0.022 V after 100 hours of driving at room temperature. Note that p-D1, HT-1, H-1, D-1, ET-1, and 2E-1 are the compounds shown below.

[0360] [Chemical Formula 72]

[0361]

[0362] Examples 27 to 50, Comparative Examples 13 to 24

[0363] An organic EL device was produced in the same manner as in Example 26 except that the compound, metal element, and the vapor deposition rate ratio between the compound and the metal element were changed as shown in Table 2. Table 2 shows the results of each example and comparative example.

[0364] [Table 2]

[0365] [Table 2]

[0366]

[0367] Example 51

[0368] A glass substrate (Geomatec (co., Ltd., 11Ω / □, sputtered product) with a 165nm ITO transparent conductive film deposited as an anode was cut into 38mm×46mm and etched. The obtained substrate was ultrasonically cleaned for 15 minutes using "Semico Clean" 56 (trade name, Furuuchi Chemical (co., Ltd.) and then washed with ultrapure water. This substrate was subjected to UV-ozone treatment for 1 hour just before the production of the organic EL element, and was placed in a vacuum evaporation device and evacuated until the vacuum degree in the device reached 5×10 -4 Pa or less. First, 5 nm of p-D1 was deposited as a hole injection layer using resistance heating. Next, a light-emitting unit (first light-emitting unit) including a hole transport layer, a light-emitting layer, and an electron transport layer was formed on the hole injection layer.

[0369] Specifically, 50 nm of HT-1 was evaporated as a hole transport layer. Next, as a light-emitting layer, a mixed layer of the main material H-1 and the dopant material D-1 was evaporated to a thickness of 20 nm at a doping concentration of 5 wt%. Next, as an electron transport layer, ET-1 and 2E-1 were evaporated to a thickness of 35 nm at a deposition rate ratio of ET-1:2E-1=1:1.

[0370] On the first light-emitting unit, as an N-type charge generation layer, compound 1 and metal element Yb as a dopant material are evaporated at a deposition rate ratio of compound 1:Yb=9:1 for 10nm. Next, 10nm of p-D1 is evaporated as a P-type charge generation layer.

[0371] Following the charge generation layer, a second light-emitting unit was formed in the same manner as the first. Next, as an electron injection layer, Compound 1 and metallic Yb, a dopant material, were vapor-deposited to a thickness of 10 nm at a deposition rate ratio of Compound 1:Yb = 9:1. Next, 60 nm of aluminum was vapor-deposited to form the cathode, creating a 5 mm x 5 mm square organic EL device.

[0372] The organic EL element was evaluated by the aforementioned method. The results showed that the initial driving voltage was 8.93 V, the external quantum efficiency (luminous efficiency) was 10.48%, the durable life was 2190 hours, and the voltage rise when driven for 100 hours at room temperature was 0.009 V.

[0373] Examples 52 to 75, Comparative Examples 25 to 36

[0374] An organic EL device was produced in the same manner as in Example 51, except that the compound used and the vapor deposition rate ratio of the compound to the metal element were changed as shown in Table 3. Table 3 shows the results of each of the Examples and Comparative Examples.

[0375] [Table 3]

[0376] [Table 3]

[0377]

[0378] In Examples 1 to 25, the results of single-charge elements obtained by using the compound represented by the general formula (1) together with Li as an alkali metal element and Yb as a rare earth metal element are shown. On the other hand, in Comparative Examples 1 to 12, the results of light-emitting elements obtained by using compounds 12 to 16 (which are not compounds represented by the general formula (1)) together with Li as an alkali metal element and Yb as a rare earth metal element are shown. Compared with each comparative example, the initial driving voltage of each embodiment is low and the increase in driving voltage is small. It can be understood that the reason is that compared with compounds 12 to 16, the coordination interactions of compounds 1 to 11 represented by the general formula (1) to the alkali metal element and the rare earth metal element are strong, and the charge generation efficiency and electron transport properties become higher, so the carrier balance is stable and the voltage increase during driving can be suppressed.

[0379] In addition, Examples 1 to 14 show the results of single-charged devices containing the compound represented by general formula (1) and Yb as a rare earth metal element, and Examples 15 to 25 show the results of single-charged devices containing Li as an alkali metal element instead of Yb. As can be understood from these results, it can be seen that by using the compound represented by general formula (1) together with a rare earth metal element, a stable layer with less increase in driving voltage can be formed.

[0380] In Examples 26 to 50, the results of applying the organic layers used in Examples 1 to 25 to light-emitting elements are shown. In Comparative Examples 13 to 24, the results of applying the organic layers used in Comparative Examples 1 to 12 to light-emitting elements are shown. Compared with the comparative examples, the driving voltage of each example is low, the external quantum efficiency is high, the durability is improved, and the driving voltage increase is small. In this regard, it can be seen that, similar to the results of the single-charge element, the compound represented by general formula (1) efficiently forms a more stable light-emitting element with a small driving voltage increase.

[0381] In addition, Examples 25 to 39 show the results of light-emitting devices containing the compound represented by general formula (1) and Yb as a rare earth metal element, and Examples 40 to 50 show the results of light-emitting devices containing Li as an alkali metal element instead of Yb. As can be understood from these results, it can be seen that by using the compound represented by general formula (1) together with a rare earth metal element, a stable layer with less increase in driving voltage can be formed.

[0382] In Examples 51 to 75, the results of applying the light-emitting elements used in Examples 26 to 50 to tandem light-emitting elements are shown. In Comparative Examples 25 to 36, the results of applying the light-emitting elements used in Comparative Examples 13 to 24 to tandem light-emitting elements are shown. Compared with the comparative examples, the driving voltage of each example is low, the external quantum efficiency is high, the durability is improved, and the driving voltage rise is small. In this regard, it can be seen that, similar to the results of the light-emitting elements used in Examples 26 to 50 and Comparative Examples 13 to 24, the compound represented by general formula (1) efficiently forms a more stable tandem light-emitting element with less driving voltage rise.

[0383] In addition, Examples 51 to 64 show the results of tandem light-emitting devices containing the compound represented by general formula (1) and Yb as a rare earth metal element, and Examples 65 to 75 show the results of tandem light-emitting devices containing Li as an alkali metal element instead of Yb. As can be understood from these results, it can be seen that by using the compound represented by general formula (1) together with a rare earth metal element, a stable layer with less increase in driving voltage can be formed.

Claims

1. A compound represented by the following general formula (1), [Chemical Formula 1] In the general formula (1), R 1 and R 2 are each independently selected from the group consisting of substituted or unsubstituted aryl and substituted or unsubstituted heteroaryl; R 1 and R 2 Can be connected to each other to form a ring structure; R 3 is selected from the group consisting of a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heteroaryl group; L is a substituted or unsubstituted arylene group, or a substituted or unsubstituted heteroarylene group; A is a structure represented by the following general formula (2) or (3); [Chemical Formula 2] [Chemical Formula 3] In general formulas (2) and (3), R 4 ~R 14 are each independently selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heteroaryl group; wherein, R 4 ~R 11 One of them is directly connected to L, R 12 ~R 14 One of them is directly connected to L; R 7 and R 8 Can be connected to each other to form a ring structure; X 1 ~X 8 are each independently a carbon atom or a nitrogen atom; wherein, X 1 and X 2 At least one of X is a nitrogen atom, 3 ~X 8 At least one of them is a nitrogen atom.

2. The compound according to claim 1, wherein In the general formula (1), R 1 and R 2 The total number of carbon atoms in is 8 to 20.

3. The compound according to claim 1, wherein In the general formula (1), R 3 The number of carbon atoms in is 1 to 12.

4. The compound according to claim 1, wherein In the general formula (1), L is a phenylene group, a naphthylene group or a biphenylene group.

5. The compound according to claim 1, wherein In the general formula (1), A is represented by any one of the following general formulas (4) to (6), [Chemical Formula 4] [Chemical Formula 5] [Chemical Formula 6] In general formulas (4) to (6), R 4 ~R 10 、R 15 and R 16 are each independently selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heteroaryl group; X 3 ~X 6 are each independently a carbon atom or a nitrogen atom; wherein, X 3 ~X 6 At least one of them is a nitrogen atom; * represents the connection position with L.

6. The compound according to claim 5, wherein In the general formulas (4) and (5), R 5 ~R 10 、R 15 and R 16 A hydrogen atom.

7. The compound according to claim 5, wherein In the general formula (6), X 3 is a nitrogen atom and X 4 ~X 6 Any one of them is a nitrogen atom.

8. A light-emitting device comprising at least an electron transport layer and a light-emitting layer between an anode and a cathode, and emitting light using electrical energy, wherein the electron transport layer contains the compound according to claim 1.

9. The light-emitting element according to claim 8, wherein The electron transport layer further contains alkali metal atoms or rare earth metal atoms.

10. A light-emitting device comprising at least a charge generation layer and a light-emitting layer between an anode and a cathode, and emitting light using electrical energy, wherein the charge generation layer contains the compound according to claim 1.

11. The light-emitting element according to claim 10, wherein The charge generating layer further contains a phenanthroline derivative.

12. The light-emitting element according to claim 10, wherein The charge generation layer further contains alkali metal atoms, copper group atoms, or rare earth metal atoms.

13. The light-emitting element according to claim 10, wherein The charge generation layer further contains an alkali metal atom, and the alkali metal atom is Li.

14. The light-emitting element according to claim 10, wherein The charge generation layer further contains rare earth metal atoms, and the rare earth metal atoms are Yb.

15. A light-emitting device comprising at least an electron injection layer and a light-emitting layer between an anode and a cathode, and emitting light using electrical energy, wherein the electron injection layer contains the compound according to claim 1.

16. The light-emitting element according to claim 15, wherein The electron injection layer further contains alkali metal atoms or rare earth metal atoms.

17. A display device comprising the light-emitting element according to any one of claims 8 to 11, 15 and 16.

18. A lighting device comprising the light-emitting element according to any one of claims 8 to 11, 15 and 16. A photosensitizer comprising the light-emitting element according to any one of claims 8 to 11, 15 and 16.

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