Compound and organic electroluminescent device

Abstract

According to the present invention, a compound having a peak wavelength of an emission spectrum in a blue wavelength region and capable of realizing light emission with high efficiency, and an organic electroluminescent device having a light emitting layer containing the compound are provided.SOLUTION: The present invention relates to a compound having a specific nitrogen-containing condensed ring structure and a specific degree of transition dipole moment orientation. The present invention also relates to an organic electroluminescent device having a light emitting layer containing a compound having a specific nitrogen-containing condensed ring structure and having a specific degree of transition dipole moment orientation. Further, the present invention also relates to an organic electroluminescent device having a light emitting layer containing a compound having a specific nitrogen-containing condensed ring structure and a specific degree of transition dipole moment orientation, and a phosphorescent complex.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a compound and an organic electroluminescent device. [Background technology]

[0002] In recent years, organic electroluminescence elements (hereinafter also referred to as "organic EL elements") have been used as various light-emitting devices, including smartphones and televisions. The light-emitting layer of an organic EL element uses a light-emitting material, and examples of such light-emitting materials include fluorescent materials, phosphorescent materials, and thermally delayed activated fluorescent materials (Non-Patent Document 1). Due to the principle of light emission, organic EL elements using fluorescent materials that utilize only fluorescent emission from singlet states have been put to practical use. However, the luminous efficiency of typical organic EL elements is 5% or less. Furthermore, organic EL elements using phosphorescent materials have a luminous efficiency of over 20%, and have already been put to practical use in green and red. However, for blue, fluorescent emission is still used due to the device's long lifespan, and there is a demand for improved performance.

[0003] In recent years, organic EL devices that combine a phosphor sensitizer with an emissive material have been proposed as a way to extend the device's lifetime while improving its luminous efficiency (Non-Patent Document 2). Conventional organic EL devices use a host material and an emissive material in the emissive layer. Excitons generated on the host material molecules in the emissive layer transfer energy to the emissive material, resulting in light emission. When a fluorescent material is used as the emissive material, the luminous efficiency is a maximum of 5%. However, adding a phosphor sensitizer to the emissive layer allows the triplet energy, which was previously unavailable, to be utilized for light emission, improving the luminous efficiency of the organic EL device to over 10%. Furthermore, it has been reported that the device lifetime is longer than when a phosphor sensitizer is used as the emissive material, and this is attracting attention as a candidate for next-generation organic EL devices.

[0004] However, even organic EL elements that combine a fluorescent sensitizer and a light-emitting material have inferior external quantum efficiency compared to organic EL elements that use phosphorescent materials, and therefore there is a demand for light-emitting materials that can achieve even higher efficiency organic EL elements.

[0005] In order to improve the external quantum efficiency of an organic EL device, it is necessary to improve the light extraction efficiency. Non-Patent Document 3 reports that by aligning the transition dipole moment of the luminescent material in a film containing the luminescent material formed on a substrate surface in a direction horizontal to the substrate surface, the inefficient vertically aligned luminescent material that cannot contribute to light emission as a device disappears, thereby improving the light extraction efficiency. Non-Patent Document 3 also shows that the molecular orientation of the luminescent material is related to the improvement of the external quantum efficiency.

[0006] [ka]

[0007] Furthermore, angle-resolved photoluminescence (PL) measurements have been reported as a method for measuring the molecular orientation of light-emitting materials (Non-Patent Document 4). The TDO value obtained from angle-resolved PL measurements corresponds to a quantity that represents the statistical degree of orientation of the transition dipole moment.

[0008] In addition, there have been reports of the application of derivatives having a basic skeleton of a compound represented by formula (S1) (hereinafter referred to as nitrogen-containing fused polycyclic compound S1) to organic electronic devices. Patent Document 1 reports that when a derivative of nitrogen-containing fused polycyclic compound S1 is used as the active layer of an organic transistor, it exhibits p-type channel characteristics and high hole mobility. Patent Document 2 reports that a derivative of nitrogen-containing fused polycyclic compound S1 having an aryl group introduced as a substituent functions as a light-emitting material for an organic EL device, and that the organic EL device exhibits high luminous efficiency. Thus, Patent Documents 1 and 2 demonstrate that nitrogen-containing fused polycyclic compound S1 is an excellent basic skeleton for organic semiconductor materials. Patent Document 3 also demonstrates that an organic EL device using a derivative of nitrogen-containing fused polycyclic compound S1 as a light-emitting material in combination with a phosphorescent complex can be fabricated, exhibiting blue light emission with a luminous efficiency of 5% or more and a spectral half-width of 20 nm or less, and exhibiting a narrow spectral half-width. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] International Publication No. 2013 / 084805 [Patent Document 2] Japanese Patent Application Publication No. 2020-107742 [Patent Document 3] Japanese Patent Application Publication No. 2020-107742 [Non-patent literature]

[0010] [Non-Patent Document 1] Adachi Chinaya (ed.), "Device Properties of Organic Semiconductors," Kodansha, March 22, 2012 [Non-patent document 2] Advanced Science,2021,9,4990. DOI:10.1038 / s41467-018-07432-2 [Non-patent document 3] J. Frischeisen, D. Yokoyama et al.,Org.Electron.12,809-817(2011) [Non-patent document 4] Sun, J.W.;Lee,J.-H.;Moon,C.-K.;Kim,K.-H.;Shin,H.;Kim,J.-J.,Adv.Mater.2014,26(32),5684~5688. Summary of the Invention [Problem to be solved by the invention]

[0011] However, further improvement in efficiency (superior luminous efficiency) is required for practical application in current organic EL devices. That is, further improvement in efficiency (superior luminous efficiency) is required for practical application of derivatives having the nitrogen-containing fused polycyclic compound S1 as a basic skeleton in current organic EL devices.

[0012] Therefore, an object of the present invention is to provide a compound having an emission spectrum with a peak wavelength in the blue wavelength region and capable of realizing highly efficient light emission. Another object of the present invention is to provide an organic electroluminescence device having an emission layer containing the compound. And still another object of the present invention is to provide a means for realizing an organic electroluminescence device having an emission spectrum with a peak wavelength in the blue wavelength region and capable of realizing highly efficient light emission. [Means for solving the problem]

[0013] In order to solve the above-mentioned problems, the present inventors conducted extensive research. They discovered that the above-mentioned problems can be solved by a compound having a specific nitrogen-containing fused polycyclic structure, a molecular weight of 1000 or more and 1400 or less, and a biaxial molecular length satisfying a specific relationship. As a result, the present inventors have completed the present invention. Furthermore, the compounds of the present invention having a specific nitrogen-containing fused polycyclic structure, a molecular length in the biaxial direction satisfying a specific relationship, and a molecular weight of 1000 or more and 1400 or less, can be used, but are not limited to, in an emissive layer. When the compounds are incorporated into the emissive layer, particularly when incorporated in combination with a phosphorescent material, the organic electroluminescent device can achieve significantly higher efficiency (significantly superior luminous efficiency). Here, in this specification, the biaxial molecular length refers to the two directions connecting opposing benzene rings among the four benzene rings located on the outer sides of the nitrogen-containing fused polycyclic compound S1. The two axes representing these biaxial directions intersect, but the angle at which they intersect is not particularly limited.

[0014] That is, at least one of the above-mentioned objects of the present invention can be achieved by the following means: The following formula (1):

[0015] [ka]

[0016] In formula (1), R 1 ~R 4 are each independently the following (1a) to (1d): (1a) a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms; (1b) a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms; (1c) a substituted or unsubstituted aromatic hydrocarbon group; or (1d) substituted or unsubstituted heterocyclic groups; and n1 to n4 are each independently 1, 2, 3, or 4, and when n1 is 2 or more, each R1 may be the same or different, and when n2 is 2 or more, each R 2 may be the same or different, and when n3 is 2 or more, each R 3 may be the same or different, and when n4 is 2 or more, each R 4 may be the same or different: is a compound represented by the molecular weight of the compound is 1000 or more and 1400 or less, The molecular length L1 and molecular length L2 of the compound in the biaxial directions defined by the following formula are each independently 16 Å or more and 38 Å or less, The product of the molecular length L1 and the molecular length L2 is 490 Å 2 More than 1200Å 2 A compound which is:

[0017]

number

[0018] Furthermore, at least one of the above-mentioned problems of the present invention can be solved by the following means: An organic electroluminescence device having a light-emitting layer containing a compound having a structure represented by the above formula (1) and a molecular weight of 1000 or more and 1400 or less, the molecular lengths in the two axial directions of which satisfy a specific relationship.

[0019] Furthermore, at least one of the above-mentioned problems of the present invention can be solved by the following means: An organic electroluminescence device having an emitting layer containing a compound having a structure represented by the above formula (1) and a molecular weight of 1000 or more and 1400 or less, the molecular lengths in the two axial directions of which satisfy a specific relationship, and a phosphorescent complex.

[0020] Furthermore, at least one of the above-mentioned problems of the present invention can be solved by the following means: An organic electroluminescence device having an emitting layer containing a host material and a compound having a structure represented by the above formula (1) and having molecular weights of 1000 or more and 1400 or less, the molecular lengths in the two axial directions of which satisfy a specific relationship. [Effects of the Invention]

[0021] According to one embodiment of the present invention, it is possible to provide a compound having an emission spectrum with a peak wavelength in the blue wavelength region and capable of realizing highly efficient light emission. According to another embodiment of the present invention, it is possible to provide an organic electroluminescence device including the compound. According to another embodiment of the present invention, it is possible to provide a means for realizing an organic electroluminescence device having an emission spectrum with a peak wavelength in the blue wavelength region and capable of realizing highly efficient light emission. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a cross-sectional view showing an organic electroluminescence element according to one embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view illustrating an organic electroluminescence element according to another embodiment of the present invention. [Figure 3] FIG. 10 is a cross-sectional view illustrating an organic electroluminescence element according to another embodiment of the present invention. [Figure 4] 1 is a graph showing the correlation between the molecular length and the transition dipole moment orientation degree TDO of a compound according to one embodiment of the present invention. [Figure 5] 1 is an emission spectrum of a toluene solution of a compound according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, embodiments of the present invention will be described. Note that the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the claims. Furthermore, the embodiments described in this specification can be arbitrarily combined to form other embodiments.

[0024] As used herein, "P and Q are each independently" means that P and Q may be the same or different. Furthermore, as used herein, "A and / or B" means that A and B are each independently present, as well as any combination thereof. Furthermore, unless otherwise specified, concentrations and percentages represent mass concentrations and mass percentages, respectively, and ratios represent mass ratios unless otherwise specified. Furthermore, unless otherwise specified, operations and measurements of physical properties, etc., are performed at room temperature (20°C or higher and 25°C or lower) and a relative humidity of 40% RH or higher and 50% RH or lower.

[0025] In addition, in this specification, the term "group derived from a ring" refers to a group obtained by removing from a ring structure hydrogen atoms directly bonded to ring-forming atoms in an amount equal to the valence, resulting in a free valence. Here, the ring-forming atoms refer to atoms that directly form the ring structure. For example, in the case of a benzene ring, the ring-forming atoms are carbon atoms, and hydrogen atoms are not included in the ring-forming atoms.

[0026] According to the present invention, a compound capable of realizing high efficiency of an organic electroluminescence device (organic EL device) is provided.

[0027] The following nitrogen-containing condensed polycyclic compound S1 is known as a known material, but the organic EL device using the nitrogen-containing condensed polycyclic compound S1 has a problem of low efficiency. Therefore, the light extraction efficiency (η out ) and investigated ways to improve the efficiency (excellent luminous efficiency) of organic EL elements.

[0028] [ka]

[0029] Light extraction efficiency: η ext =η int ×η out (ii) η ext : External quantum efficiency η int: Internal quantum efficiency η out : Light extraction efficiency.

[0030] It is generally known that light extraction efficiency can be improved by orienting the molecules so that the transition dipole moment of the dopant is parallel to the substrate (light-emitting layer). Various analyses of derivatives of nitrogen-containing fused polycyclic compound S1 that have been synthesized so far have revealed a correlation between the biaxial molecular length of the compound and the transition dipole moment orientation degree (TDO) of the compound in a thin film (hereinafter simply referred to as "TDO"). Therefore, according to the present invention, by calculating the biaxial molecular length of the compound from simulation results using DFT calculations, it is possible to design and synthesize a compound with a high transition dipole moment orientation degree (TDO) in a thin film. Using this compound as a dopant in the light-emitting layer can provide a highly efficient organic EL device (e.g., a blue organic EL device).

[0031] The compound of the present invention is represented by the following formula (1), and the molecular lengths L1 and L2 in the two axial directions defined by the following formula are each independently 16 Å or more and 38 Å or less, and the product of the molecular lengths L1 and L2 is 490 Å. 2 More than 1200Å 2 Hereinafter, the compound represented by formula (1) will also be referred to as "a compound of formula (1)" or "a compound of the present invention."

[0032] [ka]

[0033] R 1 ~R 4 are each independently (1a) to (1d) below: (1a) a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms; (1b) a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms; (1c) a substituted or unsubstituted aromatic hydrocarbon group; or (1d) substituted or unsubstituted heterocyclic groups; and n1 to n4 are each independently 1, 2, 3, or 4, and when n1 is 2 or more, each R 1 may be the same or different, and when n2 is 2 or more, each R 2 may be the same or different, and when n3 is 2 or more, each R 3 may be the same or different, and when n4 is 2 or more, each R 4 may be the same or different.

[0034]

number

[0035] According to a preferred embodiment, the compound represented by formula (1) is represented by the following formula (2), and the molecular lengths L3 and L4 in the two axial directions defined by the following formula are each independently 16 Å or more and 38 Å or less, and the product of the molecular lengths L3 and L4 is 490 Å or less. 2 More than 1200Å 2 The compound has a molecular weight of 1,000 or more and 1,400 or less.

[0036] [ka]

[0037] In equation (2), A a ~A d are each independently a benzene ring or a heterocycle, R a ~R deach independently represents a hydrogen atom, an unsubstituted alkyl group having from 1 to 20 carbon atoms, an unsubstituted alkoxy group having from 1 to 20 carbon atoms, an unsubstituted arylamino group having from 6 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted aromatic heterocyclic group; na is A a is a benzene ring, then 5, and A a When is a heterocycle, A a is the upper limit of the number of substitutions that can be made into nb is A b is a benzene ring, then 5, and A b When is a heterocycle, A b is the upper limit of the number of substitutions that can be made into nc is A c is a benzene ring, then 5, and A c When is a heterocycle, A c is the upper limit of the number of substitutions that can be made into nd is A d is a benzene ring, then 5, and A d When is a heterocycle, A d is the upper limit of the number of substitutions that can be made into X 1 ~X 4 are each independently a hydrogen atom, an unsubstituted alkyl group having from 1 to 20 carbon atoms, an unsubstituted alkoxy group having from 1 to 20 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group, m1 to m4 are 3:

[0038]

number

[0039] Here, the "substitutable number" refers to the number of substitutions that can be made in the structure of the compound. For example, A a is a carbazole ring, the number of possible substitutions is 8. Also, for example, when na R a When all of are hydrogen atoms, it means that there are no substituents and that the group is unsubstituted.

[0040] According to a more preferred embodiment, the compound represented by formula (1) is represented by the following formula (3), and the molecular lengths L5 and L6 in the two axial directions defined by the following formula are each independently 16 Å or more and 38 Å or less, and the product of the molecular lengths L5 and L6 is 490 Å or less. 2 More than 1200Å 2 The compound has a molecular weight of 1,000 or more and 1,400 or less.

[0041] [ka]

[0042] In equation (3), R 5 ~R 8 are each independently a hydrogen atom, an unsubstituted alkyl group having from 1 to 20 carbon atoms, an unsubstituted alkoxy group having from 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted aromatic heterocyclic group, n5 to n8 are 5, Y 1 ~Y 4 are each independently a hydrogen atom, an unsubstituted alkyl group having from 1 to 20 carbon atoms, an unsubstituted alkoxy group having from 1 to 20 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group, ng~nj is 3.

[0043]

number

[0044] That is, the compound of the present invention is a compound represented by formula (1) and having a molecular weight of 1000 to 1400, inclusive, in which the biaxial molecular lengths L1 and L2 satisfy a specific relationship; a compound represented by formula (2) and having a molecular weight of 1000 to 1400, inclusive, in which the biaxial molecular lengths L3 and L4 satisfy a specific relationship; or a compound represented by formula (3) and having a molecular weight of 1000 to 1400, inclusive, in which the biaxial molecular lengths L5 and L6 satisfy a specific relationship. According to a preferred embodiment, the transition dipole moment orientation degree (TDO) of the compound of the present invention in a thin film is greater than 90% and not more than 100%. By incorporating the compound of the present invention in the light-emitting layer, particularly by incorporating the compound in combination with a phosphorescent material (more preferably a phosphorescent complex) in the light-emitting layer, significantly improved efficiency (significantly superior luminous efficiency) of the organic EL device can be achieved.

[0045] In the following, unless otherwise specified, the physical properties of the compound represented by formula (1) are assumed to be the same as those of the compound represented by formula (2) and the compound represented by formula (3). In addition, the compound represented by formula (4) described below is assumed to have the same physical properties as the compound represented by formula (1).

[0046] As described above, according to a preferred embodiment, the transition dipole moment orientation degree (TDO) of the compound represented by the above formula (1) in the thin film is greater than 90% and less than or equal to 100%. The present inventors have found that the TDO can be increased (i.e., approached to 100%) by forming a compound having a structure in which the molecular length is extended in two directions (biaxial directions). That is, increasing the TDO can be achieved by designing a compound so that the molecular length is extended in two directions (biaxial directions). For example, when the substituent R 1 The terminal groups and substituents R 3 The direction of connecting the terminal groups of the substituent R 2 The terminal groups and substituents R 4 The substituent R 1 ~R 4 Specifically, as shown in the following formula (4), each R1 ~R 4 , R 1 is R 1a ~R 1d ;R 2 is R 2a ~R 2d ;R 3 is R 3a ~R 3d and;R 4 is R 4a ~R 4d ;When referring to 1b and R 3b ; and R 1c and R 3c and at least one combination selected from R 2b and R 4b ; and R 2c and R 4c and at least one combination selected from the group consisting of (1a) and (1d). 1b and R 3b ; and R 1c and R 3c and at least one combination selected from R 2b and R 4b ; and R 2c and R 4c and at least one combination selected from the above, preferably having the group (1c) or (1d).

[0047] [ka]

[0048] The reason why the TDO can be increased (i.e., approached to 100%) by using a compound with a structure in which the molecular length is extended in two axial directions is presumed to be as follows.

[0049] For example, if a compound has a structure in which the molecular length is extended in two directions, the molecules become large and planar, which makes them more likely to align horizontally in the light-emitting layer. This can result in the transition dipole moment orientation degree (TDO) of the compound being between 90% and 100%.

[0050] The above mechanism is based on speculation, and its correctness does not affect the technical scope of the present invention. Similarly, the correctness of other speculations in this specification does not affect the technical scope of the present invention.

[0051] Another aspect of the present invention is the discovery that, in a compound represented by formula (1), the molecular lengths in the biaxial directions correlate with the transition dipole moment orientation degree TDO of the compound in a thin film (hereinafter, this correlation will be referred to as the "relationship of the present invention"). Based on this finding, it has been discovered that, in a compound represented by formula (1), the above-mentioned problems can be solved by controlling the molecular lengths in the biaxial directions of the compound (types of substituents and their substitution positions) according to the transition dipole moment orientation degree TDO of the target compound in a thin film.

[0052] That is, one aspect of the present invention involves controlling the transition dipole moment orientation degree (TDO) in a thin film of a compound represented by the above formula (1) by appropriately selecting the biaxial molecular length (type and substitution position of substituents) of a target compound. Another aspect of the present invention involves determining the biaxial molecular length (type and substitution position of substituents) of a target compound represented by the above formula (1) according to the transition dipole moment orientation degree (TDO) of the compound.

[0053] The transition dipole moment orientation degree (TDO) of the compound represented by formula (2) in the thin film is greater than 90% and less than or equal to 100%. In the compound represented by formula (2), the biaxial molecular length correlates with the transition dipole moment orientation degree (TDO) of the compound in the thin film (there is a "relationship of the present invention"). Therefore, one aspect of the present invention involves controlling the transition dipole moment orientation degree (TDO) of the compound in the thin film by appropriately selecting the biaxial molecular length (type of substituent and its substitution position) of the compound represented by formula (2). Another aspect of the present invention involves determining (controlling) the biaxial molecular length (type of substituent and its substitution position) of the compound represented by formula (2) in accordance with the transition dipole moment orientation degree (TDO) of the target compound in the thin film.

[0054] In a preferred embodiment, the transition dipole moment orientation degree (TDO) of the compound represented by formula (3) in a thin film is greater than 90% and not greater than 100%. In the compound represented by formula (3), the biaxial molecular length correlates with the transition dipole moment orientation degree (TDO) of the compound in a thin film (having the "relationship of the present invention"). Therefore, one aspect of the present invention involves controlling the transition dipole moment orientation degree (TDO) of the compound in a thin film by appropriately selecting the biaxial molecular length (type of substituent and its substitution position) of the compound represented by formula (3). Another aspect of the present invention involves determining (controlling) the biaxial molecular length (type of substituent and its substitution position) of the compound represented by formula (3) in accordance with the transition dipole moment orientation degree (TDO) of the target compound in a thin film.

[0055] In the present invention, in view of existing technologies, a compound (i.e., a compound represented by formula (1)) in which a substituent that improves light extraction efficiency is introduced into a nitrogen-containing fused polycyclic compound S1 was designed as a method for improving the efficiency of organic EL devices without impairing the optical properties of the light-emitting material. This makes it possible to provide a blue-emitting material (i.e., a compound represented by formula (1)) with a high transition dipole moment orientation degree TDO in a thin film, a composition using the same, an organic EL device, and an organic EL display equipped with the organic EL device.

[0056] As described above, one aspect of the present invention relates to a compound represented by formula (1). Another aspect of the present invention also relates to an organic electroluminescence device having an emitting layer containing a compound represented by formula (1). Yet another aspect of the present invention also relates to an organic electroluminescence device having an emitting layer containing a compound represented by formula (1) below and a phosphorescent complex described below.

[0057] Hereinafter, the compound represented by the above formula (1) according to one embodiment of the present invention and the compound represented by the above formula (1) contained in the light-emitting layer of the organic electroluminescence device according to one embodiment of the present invention will be described.

[0058] <Compound represented by formula (1)> The present invention relates to a compound represented by the following formula (1):

[0059] [ka]

[0060] In formula (1), R 1 ~R 4 are each independently the following (1a) to (1d): (1a) a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms; (1b) a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms; (1c) a substituted or unsubstituted aromatic hydrocarbon group; or (1d) substituted or unsubstituted heterocyclic groups; and n1 to n4 are each independently 1, 2, 3, or 4, and when n1 is 2 or more, each R 1 may be the same or different, and when n2 is 2 or more, each R 2 may be the same or different, and when n3 is 2 or more, each R 3 may be the same or different, and when n4 is 2 or more, each R 4 may be the same or different.

[0061] In the formula (1), among the groups (1a) to (1d), the groups (1a), (1b) and (1c) are preferred, and the groups (1a) and (1c) are more preferred.

[0062] In the formula (1), when the groups (1a) to (1d) are substituted, the substituents substituting these groups are not particularly limited. However, in the formula (1), the substituents substituting the groups (1a) to (1d) are preferably each independently at least one substituent selected from the group consisting of a halogen atom, a cyano group, an alkyl group having 1 to 20 carbon atoms, a haloalkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an arylamino group having 6 to 20 carbon atoms, an aromatic hydrocarbon group having 6 to 30 carbon atoms, and a heterocyclic group having 3 to 30 ring atoms. These substituents may be substituted, but are preferably unsubstituted.

[0063] The alkyl group (1a) having 1 to 20 carbon atoms is not particularly limited and may be linear, branched, or cyclic. Of these, linear or branched is preferred from the viewpoint of luminous efficiency. The number of carbon atoms in the alkyl group is preferably 2 or more, more preferably 3 or more, and even more preferably 4 or more, from the viewpoint of luminous efficiency. Furthermore, the number of carbon atoms in the alkyl group is preferably 10 or less, more preferably 8 or less, and even more preferably 6 or less, from the viewpoint of luminous efficiency. From these viewpoints, the number of carbon atoms in the alkyl group is particularly preferably 4. Specific examples of the alkyl group include, but are not limited to, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an s-butyl group (sec-butyl group), a t-butyl group (tert-butyl group), an i-butyl group, a 2-ethylbutyl group, a 3,3-dimethylbutyl group, an n-pentyl group, an i-pentyl group, a neopentyl group, a t-pentyl group, a cyclopentyl group, a 1-methylpentyl group, a 3-methylpentyl group, a 2-ethylpentyl group, a 4-methyl-2-pentyl group, an n-hexyl group, a 1-methylhexyl group, a 2-ethylhexyl group, a 2-butylhexyl group, a cyclohexyl group, a 4-methylcyclohexyl group, a 4-t-butylcyclohexyl group, an n-heptyl group, a 1-methylheptyl group, a 2,2-dimethylheptyl group, a 2-ethylhexyl group, a 4-methylcyclohexyl group, a 4-t-butylcyclohexyl group, an n-heptyl group, a 1-methylheptyl group, a 2,2-dimethylheptyl group, a 2-ethylhexyl group, a 4-methyl-2-pentyl group, a 4-ethylhex ... ethylheptyl group, 2-butylheptyl group, n-octyl group, t-octyl group, 2-ethyloctyl group, 2-butyloctyl group, 2-hexyloctyl group, 3,7-dimethyloctyl group, cyclooctyl group, n-nonyl group, n-decyl group, adamantyl group, 2-ethyldecyl group, 2-butyldecyl group, 2-hexyldecyl group, 2-octyldecyl group, n-undecyl group Examples of the alkyl group include an n-dodecyl group, a 2-ethyldodecyl group, a 2-butyldodecyl group, a 2-hexyldodecyl group, a 2-octyldecyl group, an n-tridecyl group, an n-tetradecyl group, an n-pentadecyl group, an n-hexadecyl group, a 2-ethylhexadecyl group, a 2-butylhexadecyl group, an n-heptadecyl group, an n-octadecyl group, an n-nonadecyl group, and an n-icosyl group. Among these, a branched alkyl group is preferred, an isopropyl group or a tert-butyl group is more preferred, and a tert-butyl group is even more preferred.

[0064] The term "substituted alkyl group having 1 to 20 carbon atoms" refers to a group in which an unsubstituted alkyl group having 1 to 20 carbon atoms is substituted with a substituent. Therefore, the number of carbon atoms in the substituted alkyl group may be more than 20.

[0065] The alkoxy group (1b) having 1 to 20 carbon atoms is not particularly limited, and may be linear, branched, or cyclic. Among these, linear or branched alkoxy groups are preferred from the viewpoint of luminous efficiency. The number of carbon atoms in the alkoxy group is preferably 1 to 10 from the viewpoint of luminous efficiency. From the same viewpoint, the number of carbon atoms in the alkoxy group is more preferably 1 to 8, even more preferably 1 to 6, and particularly preferably 1. The alkyl group constituting the alkoxy group is not particularly limited, and examples thereof include those described above in connection with the alkyl group. Specific examples of the alkoxy group include, but are not limited to, a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, an octyloxy group, a nonyloxy group, and a decyloxy group. Among these, a methoxy group is preferred.

[0066] The term "substituted alkoxy group having 1 to 20 carbon atoms" refers to a group in which an unsubstituted alkoxy group having 1 to 20 carbon atoms is substituted with a substituent. Therefore, the number of carbon atoms in the substituted alkoxy group may be more than 20.

[0067] The aromatic hydrocarbon group (1c) above refers to a group derived from one or more aromatic hydrocarbon rings. In this specification, the aromatic hydrocarbon ring refers to a hydrocarbon ring that is aromatic in part or as a whole.

[0068] When an aromatic hydrocarbon group contains two or more aromatic hydrocarbon rings, these rings may be bonded to each other via a single bond or may be fused together. When an aromatic hydrocarbon group contains two or more aromatic hydrocarbon rings, one atom may also serve as a ring-forming atom for any of these rings.

[0069] From the viewpoint of luminous efficiency, the number of carbon atoms in the aromatic hydrocarbon group is preferably 6 to 30, more preferably 6 to 20, even more preferably 6 to 18, and still more preferably 6 to 16.

[0070] Specific examples of aromatic hydrocarbon groups include, but are not limited to, phenyl, mesityl, isopropylphenyl, di(isopropyl)phenyl, tri(isopropyl)phenyl, tert-butylphenyl, di(tert-butyl)phenyl, tri(tert-butyl)phenyl, biphenyl (biphenylyl), (tert-butyl)biphenylyl, terphenyl, naphthyl, fluorenyl, anthracenyl, terphenyl, quaterphenyl, quinquephenyl, sexiphenyl, triphenylenyl, pyrenyl, benzofluorenyl, chrysenyl, and groups formed from combinations thereof. Among these, a tri(iso-propyl)phenyl group, a tert-butylphenyl group, a bis(tert-butyl)phenyl group, and a (tert-butyl)biphenylyl group are preferred, and for example, a 2,4,6-tri(iso-propyl)phenyl group, a 2-(tert-butyl)-4,6-di(iso-propyl)phenyl group, a 4-tert-butylphenyl group, a 3,5-di(tert-butyl)phenyl group, and a 4'-tert-butyl-4-biphenylyl group are more preferred.

[0071] The term "substituted aromatic hydrocarbon group" refers to a group in which an unsubstituted aromatic hydrocarbon group is substituted with a substituent. Therefore, when the aromatic hydrocarbon group has a specific upper limit of carbon atoms, such as 30 or less, the substituted aromatic hydrocarbon group may have more carbon atoms than the upper limit.

[0072] The heterocyclic group in (1d) above refers to a group derived from one or more heterocycles. The heterocyclic group is not particularly limited and may be an aromatic heterocyclic group or a non-aromatic heterocyclic group. Among these, from the viewpoint of the color purity of light emission, an aromatic heterocyclic group is preferred. The number of ring-forming atoms in the heterocyclic group is preferably 3 to 30, more preferably 5 to 20, and even more preferably 6 to 14. As mentioned above, the ring-forming atoms refer to atoms that directly form a ring structure. When there is an atom outside the ring that forms a double bond with an atom that forms a ring structure, this atom is not included in the ring-forming atoms.

[0073] An aromatic heterocyclic group refers to a group derived from one or more aromatic heterocycles. In this specification, an aromatic heterocycle refers to a heterocycle that is aromatic in part or in its entirety. When a part of an aromatic heterocycle is aromatic, the aromaticity may be derived from the heterocyclic moiety in the ring or from the hydrocarbon ring moiety in the ring. Examples of aromatic heterocycles include, but are not limited to, rings having one or more heteroatoms (e.g., nitrogen atom (N), oxygen atom (O), phosphorus atom (P), sulfur atom (S), and silicon atom (Si)) as ring-forming atoms, with the remaining ring-forming atoms being carbon atoms (C). Note that atoms constituting the ring structure may be bonded to atoms outside the ring via double bonds, such as when the carbon atoms constituting the ring structure form a ketone group (C=O group), a thioketone group (C=S group), or a C=NH group, or when the sulfur atoms constituting the ring structure form a sulfinyl group (S=O group) or a sulfonyl group (S(=O)=O group). In this case, in this specification, an exocyclic atom forming a double bond with an atom constituting a ring structure is considered to be part of an aromatic heterocycle. In addition, when an exocyclic atom forming a double bond is bonded to a hydrogen atom via a single bond, the hydrogen atom is also considered to be part of an aromatic heterocycle.Specific examples of the aromatic heterocycle include, but are not limited to, a pyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidine ring, a triazine ring, a quinoline ring, an isoquinoline ring, a quinoxaline ring, a quinazoline ring, a naphthyridine ring, an acridine ring, a phenazine ring, a benzoquinoline ring, a benzoisoquinoline ring, a phenanthridine ring, a phenanthroline ring, a benzoquinone ring, a coumarin ring, an anthraquinone ring, a fluorenone ring, a furan ring, a thiophene ring, a benzofuran ring, a benzothiophene ring, a dibenzofuran ring, a dibenzothiophene ring, a pyrrole ring, an indole ring, a carbazole ring, an indolocarbazole ring, and an imidazole ring. ring, benzimidazole ring, pyrazole ring, indazole ring, oxazole ring, isoxazole ring, benzoxazole ring, benzisoxazole ring, thiazole ring, isothiazole ring, benzothiazole ring, benzisothiazole ring, imidazolinone ring, benzimidazolinone ring, imidazopyridine ring, imidazopyrimidine ring, imidazophenanthridine ring, benzimidazophenanthridine ring, azadibenzofuran ring, azacarbazole ring, azadibenzothiophene ring, diazadibenzofuran ring, diazacarbazole ring, diazadibenzothiophene ring, xanthone ring, thioxanthone ring, and the like.

[0074] When an aromatic heterocyclic group contains two or more aromatic heterocyclic rings, these rings may be bonded to each other via a single bond or may be condensed together. When an aromatic heterocyclic group contains two or more aromatic heterocyclic rings, one atom may also serve as a ring-forming atom of any of these rings.

[0075] The number of ring-forming atoms (total number of ring-forming carbon atoms and ring-forming heteroatoms) of the aromatic heterocyclic group is 3 to 30, and from the viewpoints of the peak wavelength of the emission spectrum and the color purity of the emission, it is preferably 5 to 20, and more preferably 6 to 14. The number of ring-forming heteroatoms of the aromatic heterocyclic group is not particularly limited, but from the viewpoints of the peak wavelength of the emission spectrum and the color purity of the emission, it is preferably 1 to 10. Furthermore, from the same viewpoints, the number of ring-forming heteroatoms of the aromatic heterocyclic group is more preferably 1 to 5, and even more preferably 1 to 3.

[0076] Specific examples of the aromatic heterocyclic group include, but are not limited to, a thienyl group, a furanyl group, a pyrrolyl group, an imidazolyl group, a thiazolyl group, an oxazolyl group, an oxadiazolyl group, a triazolyl group, a pyridyl group, a bipyridyl group, a pyrimidyl group, a triazinyl group, an acridinyl group, a pyridazinyl group, a pyrazinyl group, a quinolinyl group, a quinazolinyl group, a quinoxalinyl group, a phenoxazinyl group, a phthalazinyl group, a pyridopyrimidinyl group, a pyridopyrazinyl group, a pyrazinopyrazinyl group, an isopropyl group, a methyl ... Examples thereof include a quinolinyl group, an indolyl group, a carbazolyl group, a benzoxazolyl group, a benzimidazolyl group, a benzothiazolyl group, a benzocarbazolyl group, a benzothiophenyl group, a dibenzothiophenyl group, a thienothienyl group, a benzofuranyl group, a phenanthrolinyl group, a thiazolyl group, an isoxazolyl group, an oxadiazolyl group, a thiadiazolyl group, a phenothiazinyl group, a dibenzosilolyl group, a dibenzofuranyl group, a xanthonyl group, etc. Among these, a triazinyl group, a carbazolyl group, a benzoxazolyl group, and a xanthonyl group are preferred.

[0077] Furthermore, the term "non-aromatic heterocyclic group" refers to a group derived from one or more non-aromatic heterocycles. In this specification, the term "non-aromatic heterocycle" refers to a heterocycle that does not have aromaticity either in part or as a whole. The non-aromatic heterocycle is not particularly limited, but examples thereof include rings having one or more heteroatoms (e.g., nitrogen atom (N), oxygen atom (O), phosphorus atom (P), sulfur atom (S), silicon atom (Si)) as ring-forming atoms, and the remaining ring-forming atoms are carbon atoms (C). From the viewpoints of the peak wavelength of the emission spectrum and the color purity of the emission, nitrogen atom (N) and oxygen atom (O) are preferred as heteroatoms. Note that, in some cases, the atoms constituting the ring structure are bonded to atoms outside the ring via a double bond, such as when the carbon atoms constituting the ring structure form a ketone group (C=O group), a thioketone group (C=S group), or a C=NH group, or when the sulfur atoms constituting the ring structure form a sulfinyl group (S=O group) or a sulfonyl group (S(=O)=O group). In this case, in the present specification, an exocyclic atom forming a double bond with an atom constituting a ring structure is considered to be part of a non-aromatic heterocycle. Also, when an exocyclic atom forming a double bond is bonded to a hydrogen atom via a single bond, the hydrogen atom is also considered to be part of the non-aromatic heterocycle. Specific examples of non-aromatic heterocycles include, but are not limited to, a pyrrolidine ring, a tetrahydrofuran ring, a tetrahydrothiophene ring, a piperidine ring, a tetrahydropyran ring, a tetrahydrothiopyran ring, a dioxane ring, a morpholine ring, and a dioxolane ring.

[0078] When a non-aromatic heterocyclic group contains two or more non-aromatic heterocyclic rings, these rings may be bonded to each other via a single bond or may be fused together. When a non-aromatic heterocyclic group contains two or more non-aromatic heterocyclic rings, one atom may also serve as a ring-forming atom of any of these rings.

[0079] The number of ring-forming atoms (total number of ring-forming carbon atoms and ring-forming heteroatoms) of the non-aromatic heterocyclic group is 3 to 30, and from the viewpoints of the peak wavelength of the emission spectrum and the color purity of the emission, it is preferably 5 to 20, and more preferably 6 to 14. The number of ring-forming heteroatoms of the non-aromatic heterocyclic group is not particularly limited, but from the viewpoints of the peak wavelength of the emission spectrum and the color purity of the emission, it is preferably 1 to 10. Furthermore, from the same viewpoints, the number of ring-forming heteroatoms of the non-aromatic heterocyclic group is more preferably 1 to 5, and even more preferably 1 to 3.

[0080] Specific examples of non-aromatic heterocyclic groups include, but are not limited to, pyrrolidinyl, tetrahydrofuranyl, tetrahydrothienyl, piperidinyl, tetrahydropyranyl, tetrahydrothiopyranyl, dioxanyl, morpholinyl, and dioxolanyl.

[0081] The term "substituted heterocyclic group" refers to a group in which an unsubstituted heterocyclic group is substituted with a substituent. Therefore, when the heterocyclic group has a specific upper limit on the number of ring atoms, such as 30 or less, and the substituent forms a ring structure, the number of ring atoms in the substituted heterocyclic group may exceed the upper limit.

[0082] The unsubstituted alkyl group having 1 to 20 carbon atoms, the unsubstituted alkoxy group having 1 to 20 carbon atoms, the unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, and the unsubstituted heterocyclic group having 3 to 30 ring atoms, which are the substituents substituting the groups (1a) to (1d) above, are the same as the unsubstituted groups described for the groups (1a) to (1d) above.

[0083] The halogen atom as a substituent substituting the groups (1a) to (1d) above is not particularly limited, and examples thereof include a fluorine atom (F), a chlorine atom (Cl), a bromine atom (Br), an iodine atom (I), etc. Among these, a fluorine atom is preferred from the viewpoint of luminous efficiency.

[0084] The cyano group, which is a substituent substituting the groups (1a) to (1d) above, is represented as CN.

[0085] Examples of the unsubstituted haloalkyl group having 1 to 20 carbon atoms, which is a substituent substituting the groups (1a) to (1d) above, include the alkyl group described in (1a) above, in which at least one hydrogen atom is substituted with the halogen atom described above. From the viewpoint of luminous efficiency, the halogen atom is preferably a fluorine atom. Specific examples of the haloalkyl group include a trifluoromethyl group, a trichloromethyl group, a tribromomethyl group, and a triiodomethyl group. Among these, a fluorinated alkyl group is preferred, and a trifluoromethyl group is more preferred.

[0086] In the unsubstituted alkylamino group having 1 to 20 carbon atoms, which is a substituent substituting the groups (1a) to (1d) above, any atom constituting the unsubstituted group (1a) to (1d) above is bonded to its nitrogen atom by a single bond in the above formula (1). The alkyl group constituting the alkylamino group is not particularly limited, but is, for example, the same as that described for (1a) above. The alkylamino group is not particularly limited, and may be a monoalkylamino group or a dialkylamino group. Specific examples of alkylamino groups include, but are not limited to, an N-methylamino group, an N-ethylamino group, an N-propylamino group, an N-isopropylamino group, an N-butylamino group, an N-isobutylamino group, an N-sec-butylamino group, an N-tert-butylamino group, an N-pentylamino group, an N-hexylamino group, an N,N,N-dimethylamino group, an N-methyl-N-ethylamino group, an N,N-diethylamino group, an N,N-dipropylamino group, an N,N-diisopropylamino group, an N,N-dibutylamino group, an N,N-diisobutylamino group, an N,N-dipentylamino group, and an N,N-dihexylamino group.

[0087] The unsubstituted arylamino group having 6 to 20 carbon atoms, which is a substituent substituting the groups (1a) to (1d) above, has a nitrogen atom bonded to any of the atoms constituting the unsubstituted groups (1a) to (1d) above in the formula (1) via a single bond. The aryl group constituting the arylamino group is not particularly limited, but may be, for example, the same as the aromatic hydrocarbon group (i.e., aryl group) described in (1c) above. The arylamino group is not particularly limited, and may be either a monoarylamino group or a diarylamino group. Specific examples of the arylamino group include, but are not limited to, an N-phenylamino group, an N-biphenylamino group, an N-terphenylamino group, an N,N-diphenylamino group, and an N-biphenyl-N-phenylamino group.

[0088] Here, preferred substituents for substituting the groups (1a) to (1d) above include a halogen atom, a cyano group, an unsubstituted alkyl group having from 1 to 20 carbon atoms, an unsubstituted alkoxy group having from 1 to 20 carbon atoms, and an unsubstituted arylamino group having from 6 to 20 carbon atoms. Among these, a halogen atom and an unsubstituted alkyl group having from 1 to 20 carbon atoms are more preferred, a fluorine atom or an unsubstituted linear or branched alkyl group having from 1 to 20 carbon atoms is even more preferred, and an unsubstituted branched alkyl group having from 1 to 20 carbon atoms is particularly preferred. A fluorine atom, a methyl group, an ethyl group, an isopropyl group, and a tert-butyl group are particularly preferred.

[0089] A preferred substituent for substituting the group (1c) above is an unsubstituted branched alkyl group having from 1 to 20 carbon atoms, more preferably an unsubstituted branched alkyl group having from 1 to 10 carbon atoms, and even more preferably an unsubstituted branched alkyl group having from 1 to 5 carbon atoms, and particularly preferably, for example, an isopropyl group or a tert-butyl group.

[0090] In the compound of formula (1), R 1 ~R 4Preferably, each independently contains one or more groups selected from the following group (2X): 1 and R 3 contains one or more groups selected from the following group (2X), and R 2 and R 4 More preferably, contains one or more groups selected from the following group (2X):

[0091] [ka]

[0092] That is, in a preferred embodiment of the present invention, in the compound of formula (1), R 1 ~R 4 is a group selected from the above group (2X), and n1 to n4 are each independently 1, 2, 3, or 4, and when n1 is 2 or more, each R 1 may be the same or different, and when n2 is 2 or more, each R 2 may be the same or different, and when n3 is 2 or more, each R 3 may be the same or different, and when n4 is 2 or more, each R 4 may be the same or different. In addition, * in the above group (2X) represents a binding site.

[0093] In addition, in a more preferred embodiment of the present invention, in the compound of formula (1), R 1 ~R 4 is a group selected from the above group (2X), and n1 to n4 are each independently 1 or 2, and when n1 is 2, each R 1 may be the same or different, and when n2 is 2, each R 2 may be the same or different, and when n3 is 2, each R 3 may be the same or different, and when n4 is 2, each R 4 may be the same or different.

[0094] According to one embodiment of the present invention, the compound represented by formula (1) is a compound represented by the following formula (2):

[0095] [ka]

[0096] In equation (2), A a ~A d are each independently a benzene ring or a heterocycle, R a ~R d each independently represents a hydrogen atom, an unsubstituted alkyl group having from 1 to 20 carbon atoms, an unsubstituted alkoxy group having from 1 to 20 carbon atoms, an unsubstituted arylamino group having from 6 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted aromatic heterocyclic group; na is A a is a benzene ring, then 5, and A a When is a heterocycle, A a is the upper limit of the number of substitutions that can be made into nb is A b is a benzene ring, then 5, and A b When is a heterocycle, A b is the upper limit of the number of substitutions that can be made into nc is A c is a benzene ring, then 5, and A c When is a heterocycle, A c is the upper limit of the number of substitutions that can be made into nd is A d is a benzene ring, then 5, and A d When is a heterocycle, A d is the upper limit of the number of substitutions that can be made into X 1 ~X 4 are each independently a hydrogen atom, an unsubstituted alkyl group having from 1 to 20 carbon atoms, an unsubstituted alkoxy group having from 1 to 20 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group, m1 to m4 are 3.

[0097] In equation (2), R a At least one of R b At least one of R c At least one of, and R d At least one of R is preferably an unsubstituted alkyl group having 1 to 20 carbon atoms, an unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted aromatic heterocyclic group. a At least one of R b At least one of R c At least one of, and R d At least one of them is preferably an unsubstituted alkyl group having 1 to 20 carbon atoms or an unsubstituted alkoxy group having 1 to 20 carbon atoms.

[0098] According to one embodiment of the present invention, the compound represented by formula (1) is a compound represented by the following formula (3):

[0099] [ka]

[0100] In equation (3), R 5 ~R 8 are each independently a hydrogen atom, an unsubstituted alkyl group having from 1 to 20 carbon atoms, an unsubstituted alkoxy group having from 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted aromatic heterocyclic group, n5 to n8 are 5, Y 1 ~Y 4 are each independently a hydrogen atom, an unsubstituted alkyl group having from 1 to 20 carbon atoms, an unsubstituted alkoxy group having from 1 to 20 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group, ng~nj is 3.

[0101] In equation (3), R5 At least one of R 6 At least one of R 7 At least one of, and R 8 At least one of R is preferably an unsubstituted alkyl group having 1 to 20 carbon atoms, an unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted aromatic heterocyclic group. 5 At least one of R 6 At least one of R 7 At least one of, and R 8 At least one of them is preferably an unsubstituted alkyl group having 1 to 20 carbon atoms or an unsubstituted alkoxy group having 1 to 20 carbon atoms.

[0102] For the explanation of each group in the above formulas (2) and (3), please refer to the explanation of the groups in formula (1).

[0103] According to one embodiment, the compound of formula (1) is a compound represented by the following formula (4):

[0104] [ka]

[0105] In equation (4), R 1a ~R 1d , R 2a ~R 2d , R 3a ~R 3d and R 4a ~R 4d are each independently a hydrogen atom or the following group (1X):

[0106] [ka]

[0107] is a group selected from In this case, R 1a ~R 1dAt least one of R 2a ~R 2d At least one of R 3a ~R 3d At least one of, and R 4a ~R 4d At least one of the groups is a group selected from the group (1X), where * represents a binding site.

[0108] According to one embodiment, in the above formula (4), R 1a ~R 1d At least one of R 2a ~R 2d At least one of R 3a ~R 3d At least one of, and R 4a ~R 4d At least one of the groups is a group selected from the following group (2X): This allows the molecular length to be extended in two axial directions, and a higher TDO can be obtained.

[0109] [ka]

[0110] According to one embodiment, in the above formula (4), R 1b and R 3b ; and R 1c and R 3c and at least one combination of groups selected from the group consisting of R 2b and R 4b ; and R 2c and R 4c and at least one combination of groups selected from the above is a group selected from the group (2X). This allows the molecular length to be extended in two axial directions, and a higher TDO can be obtained. Note that * in the above group (2X) represents a binding site.

[0111] Thus, according to one embodiment, in formula (4): R 1a ~R4a (i.e., R 1a , R 2a , R 3a and R 4a ) and R 1d ~R 4d (i.e., R 1d , R 2d , R 3d and R 4d ) each independently represent a hydrogen atom or the following group (3X):

[0112] [ka]

[0113] where * represents a bonding site, R 1b ~R 4b (i.e., R 1b , R 2b , R 3b and R 4b ) and R 1c ~R 4c (i.e., R 1c , R 2c , R 3c and R 4c ) are each independently hydrogen or the following group (2X):

[0114] [ka]

[0115] where * represents a bonding site, and where R 1b and R 3b is either a hydrogen atom or a group selected from the above group (2X), and R 1c and R 3c is a hydrogen atom or a group selected from the above group (2X), and R 2b and R 4b is either a hydrogen atom or a group selected from the above group (2X), and R 2c and R 4cis either a hydrogen atom or a group selected from the above group (2X).

[0116] The molecular weight of the compound represented by formula (1) is 1000 or more and 1400 or less. If the molecular weight exceeds 1400, there is a risk of decomposition during vapor deposition. The molecular weight is preferably 1380 or less, more preferably 1350 or less, even more preferably 1300 or less, particularly preferably 1250 or less, and most preferably 1200 or less. The molecular weight of the compound represented by formula (1) is preferably more than 1000, more preferably 1010 or more, even more preferably 1020 or more, particularly preferably 1030 or more, and most preferably 1040 or more. The molecular weight is the sum of the atomic weights of the atoms constituting the compound represented by formula (1). The preferred form of the molecular weight of the compound represented by formula (1) above also applies to the compounds represented by formula (2), formula (3), and formula (4).

[0117] [Molecular length in two axial directions] The compound of formula (1) according to the present invention has molecular lengths in the two axial directions that satisfy a specific relationship. Specifically, the molecular lengths L1 and L2 in the two axial directions of the compound of formula (1) according to the present invention are defined as follows:

[0118]

number

[0119] When calculating from the molecular length L1 and the molecular length L2 are each independently 16 Å or more and 38 Å or less; The product of the molecular length L1 and the molecular length L2 is 490 Å 2 More than 1200Å 2 The following is the result.

[0120] Here, the biaxial direction means that in the compound of formula (1), R 1 From R 3 (hereinafter referred to as direction D1) and R2 From R 4 (hereinafter referred to as direction D2) and

[0121] In the following, the molecular length L1 and the molecular length L2 will be specifically explained in the case where the compound represented by formula (1) is represented by formula (4a).

[0122] [ka]

[0123] The compound represented by the formula (4a) is a compound represented by the formula (1), wherein n1 is 2; 1 is (x-1) (p-tert-butylphenyl group) of the group (2X) and (x-6) (tert-butyl group) of the group (3X); n2 is 1; R 2 is (x-2) (3,5-di-tert-butyl group) of the group (2X); n3 is 2; R 3 is (x-1) (p-tert-butylphenyl group) of the group (2X) and (x-6) (tert-butyl group) of the group (3X); n4 is 1; R 4 is (x-2) (3,5-di-tert-butyl group) of the group (2X). The compound represented by the above formula (4a) can be obtained by adding R 1b and R 3b is (x-1) (p-tert-butylphenyl group) of the group (2X); R 1d and R 3d is (x-6) (tert-butyl group) of the group (3X); R 2b and R 4b is (x-2) (3,5-di-tert-butyl group) of the group (2X). The definitions of the molecular length L1 and molecular length L2 of the compound represented by formula (1) will be explained below. For convenience, the substituent (R 1b and R 3b ;R 1d and R 3d ; and R 2b and R 4b ) will be used to explain.

[0124] In the compound represented by the formula (4a), first, the molecular length L1 in the direction D1 is calculated. 1 and the carbon atom of the substituent R 3 The longest distance L between the carbon atoms of 1x " is R 1b and R 3b The distance between the terminal carbon atoms of the group (x-1) (p-tert-butylphenyl group) of the group (2X) is measured. Here, the group (x-1) (p-tert-butylphenyl group) of the group (2X) has a plurality of terminal carbon atoms, and the longest distance between the terminal carbon atoms is referred to as "substituent R 1 and the carbon atom of the substituent R 3 The longest distance L between the carbon atoms of 1x " (For the compound of formula (4a), it is 23.1254 Å). R 1d (tert-butyl group) and R 3b Distance between terminal carbon atoms of (p-tert-butylphenyl group); R 1b (p-tert-butylphenyl group) and R 3d (tert-butyl group) terminal carbon distance; and R 1d (tert-butyl group) and R 3d (tert-butyl group); None of the distances between the terminal carbon atoms is the longest. 1 and the carbon atom of the substituent R 3 The longest distance L between the carbon atoms of 1x For example, the substituent R 1 and R 3 has two or more substituents, and the "longest distance between terminals L 1x If the same value is calculated as "Longest distance between ends L 1x " and the remaining longest distance between the ends is "Longest distance between the ends L 1y " and "Longest distance between ends L 1z In the molecular length L2 below, if the longest distance between multiple terminals is the same, the calculation is similar.

[0125] The compound represented by the above formula (4a) has a longest end-to-end distance L 1xR other than p-tert-butylphenyl group used in the calculation 1 (tert-butyl group), the longest distance between terminals L 1x The substituent R used in the calculation of 1 Substituent R other than 1 (Hereinafter, substituent R 1p ) is present, the substituent R 1p and the carbon atom bonded to the substituent R 1p The longest distance L between the carbon atoms of 1y " is calculated. As mentioned above, "R 1b and R 3b The longest distance between the ends of the carbon atoms in 1x " was adopted, so the substituent R 1d is the "longest distance between the ends L 1y In the compound represented by the above formula (4a), the longest distance between the terminals L 1y " is "substituent R 1d (tert-butyl group) and the carbon atom bonded to the substituent R 1d The longest distance between the carbon atoms of the (tert-butyl group) and the terminals of the tert-butyl group corresponds to the longest distance between the carbon atoms of the (tert-butyl group) and the terminals of the (tert-butyl group) (for the compound of formula (4a), it is 2.57896 Å). Next, for the compound represented by formula (4a), the longest distance between the terminals L 1x The substituent R used in the calculation of 3 (p-tert-butylphenyl group) 3 (tert-butyl group), the longest distance between terminals L 1x The substituent R used in the calculation of 3 Substituent R other than 3 (Hereinafter, substituent R 3p ) is present, the substituent R 3p and the carbon atom bonded to the substituent R 3p The longest distance L between the carbon atoms of 1z " is calculated. Substituent R 3d is "R 1b and R 3b The longest distance between the ends of the carbon atoms in 1x " was adopted as the "longest distance between the ends L 1zIn the compound represented by the above formula (4a), the longest distance between the terminals L 1z " is "substituent R 3d and the carbon atom bonded to the substituent R 3d The longest distance between the carbon atom of and the terminal of corresponds to this (in the compound of formula (4a), it is 2.57888 Å).

[0126] In this way, the "longest distance between the ends L 1x ”, “Maximum distance L between ends 1y " and "Longest distance between ends L 1z " are calculated and added together to calculate the molecular length L1. For example, in the compound of formula (4a), Molecular length L1=23.1254+2.57896+2.57888=28.28324Å Rounding to the second decimal place gives the result 28.3 Å.

[0127] Next, the molecular length L2 in the direction D2 of the compound represented by the above formula (4a) is calculated. 2 and the carbon atom of the substituent R 4 The longest distance L between the carbon atoms of 2x " is R 2b and R 4b The distance between the terminal carbon atoms of the group (x-2) (tert-butyl group) of the group (2X) is measured. Here, the group (x-2) (tert-butyl group) of the group (2X) has a plurality of terminal carbon atoms, and the longest distance between the terminal carbon atoms is referred to as "substituent R 2 and the carbon atom of the substituent R 4 The longest distance L between the carbon atoms of 2x " (for the compound of formula (4a), this is 22.97062 Å).

[0128] The compound represented by the above formula (4a) has a longest end-to-end distance L 2x The substituent R used in the calculation of 2 (tert-butyl group) 2 is a hydrogen atom. Therefore, the longest distance between the terminals L 2xThe substituent R used in the calculation of 2 Substituent R other than 2 (Hereinafter, substituent R 2p ) is present, the substituent R 2p and the carbon atom bonded to the substituent R 2p The longest distance L between the carbon atoms of 2y " is 0. Similarly, in the compound represented by the above formula (4a), the longest distance between the terminals, L 2x The substituent R used in the calculation of 4 (tert-butyl group) 4 is a hydrogen atom. Therefore, the longest distance between the terminals L 2x The substituent R calculated as 4 Other than R 4 (Hereinafter, substituent R 4p ) is present, the substituent R 4p and the carbon atom bonded to the substituent R 4p The longest distance L between the carbon atoms of 2z " is 0.

[0129] In this way, the "longest distance between the ends L 2x ”, “Maximum distance L between ends 2y " and "Longest distance between ends L 2z " are calculated and added together to calculate the molecular length L2. For example, in the compound of formula (4a), Molecular length L2=22.97062+0+0=22.97062Å Rounding to the second decimal place gives the result 23.0 Å.

[0130] In the compound of formula (1) according to the present invention, the molecular length L1 and molecular length L2 calculated as above are preferably 18 Å or more, more preferably 19 Å or more, even more preferably 20 Å or more, particularly preferably 21 Å or more, and most preferably 22 Å or more. The upper limit of the molecular length L1 and molecular length L2 is preferably 37 Å or less, more preferably 36 Å or less, and even more preferably 35 Å or less.

[0131] One of the features of the present invention is that not only are the molecular length L1 and the molecular length L2 within a specific range, but also that the product of the molecular length L1 and the molecular length L2 is within a specific range. The product of the molecular length L1 and the molecular length L2 is a numerical representation of a technical item called orientation TDO, and this product is 490 Å. 2 More than 1200Å 2 By ensuring that the thickness is within the following range, the effect of improving the device efficiency due to high orientation can be obtained.

[0132] The product of L1 and L2 is 490 Å 2 More than 1200Å 2 In the following cases, the TDO is 90% or more and 100% or less. On the other hand, when the product of the molecular length L1 and the molecular length L2 is 490 Å, 2 Less than or equal to 1200Å 2 If the product of molecular length L1 and molecular length L2 is 500 Å, the TDO is less than 90%. 2 More than 1180Å 2 Preferably, it is 520 Å or less. 2 Over 1150Å 2 More preferably, it is 550 Å or less. 2 More than 1140Å 2 More preferably, it is 580 Å or less. 2 More than 1135Å 2 It is particularly preferred that the thickness is 600 Å or less. 2 More than 1130Å 2 Most preferably, it is:

[0133] According to one embodiment, the molecular length L1 and the molecular length L2 are 18 Å or more and 38 Å or less, and the product of the molecular length L1 and the molecular length L2 is 500 Å or less. 2 More than 1180Å 2 According to one embodiment, the molecular length L1 and the molecular length L2 are 20 Å or more and 38 Å or less, and the product of the molecular length L1 and the molecular length L2 is 520 Å or less. 2 More than 1180Å 2 According to one embodiment, the molecular length L1 and the molecular length L2 are 21 Å or more and 31 Å or less, and the product of the molecular length L1 and the molecular length L2 is 490 Å or less. 2 More than 650Å 2 The following is the result.

[0134] When calculating the molecular length L1 and molecular length L2 as described above, the structure of the compound of formula (1) according to the present invention uses the most stable structure calculated by density functional theory (DFT) using Gaussian 16 (Gaussian Inc.) as calculation software. The molecular length is calculated using a function for measuring the distance between atoms in Gauss View. Details of the calculation of the most stable structure and molecular length are as described in the Examples. After calculating the most stable structure using Gaussian 16 (Gaussian Inc.), the molecular lengths L1 and L2 of the compound can also be calculated using software such as Gauss View, Chem 3D, and IQmol.

[0135] When the compound of formula (1) according to the present invention is represented by formula (2), the molecular lengths L1 and L2 correspond to the molecular lengths L3 and L4, and are defined as follows: In the compound of formula (2), the direction D1 is the direction of the substituent R a From the substituent R c The direction D2 corresponds to the direction connecting the substituent R b From the substituent R d This corresponds to the direction connecting these two points (hereinafter referred to as direction D2).

[0136]

number

[0137] The compound represented by the above formula (4a) is a compound represented by the formula (2), a ~A d is a benzene ring and one R a is a tert-butyl group, and four R a is a hydrogen atom, and two R b is a tert-butyl group, and three R b is a hydrogen atom and one R c is a tert-butyl group, and four R c is a hydrogen atom, and two R dis a tert-butyl group, and three R d is a hydrogen atom and one X 1 is a tert-butyl group, and two X 1 is a hydrogen atom, and three X 2 is a hydrogen atom and one X 3 is a tert-butyl group, and two X 3 is a hydrogen atom, and three X 4 is a hydrogen atom. The definitions of the molecular lengths L3 and L4 of the compound represented by formula (2) will be explained below. For convenience, the substituents (R 1b and R 3b ;R 1d and R 3d ; and R 2b and R 4b ) will be used to explain.

[0138] In the compound represented by the formula (4a), first, the molecular length L3 in the direction D1 is calculated. a and the carbon atom of the substituent R c The longest distance L between the carbon atoms of 3x " is the above-mentioned R 1b and R 3b As described above, there are multiple terminal carbon atoms in the group (x-1) (p-tert-butylphenyl group) of the group (2X), and the longest distance between the terminal carbon atoms is referred to as the "substituent R a and the carbon atom of the substituent R c The longest distance L between the carbon atoms of 3x " (for the compound of formula (4a), this is 23.1254 Å).

[0139] The compound represented by the above formula (4a) contains a substituent X other than a hydrogen atom. 1 (tert-butyl group) exists. Therefore, next, "Substituent X 1 is a group other than a hydrogen atom, the substituent X 1 and the carbon atom bonded to the substituent X 1 The longest distance L between the carbon atoms of3y In the compound represented by the above formula (4a), the "longest terminal-to-terminal distance L 3y " is "substituent R 1d (tert-butyl group) and the carbon atom bonded to the substituent R 1d The longest distance between the carbon atom of the (tert-butyl group) and the terminal of the ; corresponds to this (in the compound of formula (4a), it is 2.57896 Å). Similarly, in the compound represented by the above formula (4a), 3 (tert-butyl group) exists. Therefore, next, "Substituent X 3 is a group other than a hydrogen atom, the substituent X 3 and the carbon atom bonded to the substituent X 3 The longest distance L between the carbon atoms of 3z In the compound represented by the above formula (4a), the "longest terminal-to-terminal distance L 3z " is "substituent R 3d and the carbon atom bonded to the substituent R 3d The longest distance between the carbon atom of and the terminal of corresponds to this (in the compound of formula (4a), it is 2.57888 Å).

[0140] In this way, the "longest distance between the ends L 3x ”, “Maximum distance L between ends 3y " and "Longest distance between ends L 3z " are calculated and added together to calculate the molecular length L3 (28.3 Å for the compound of formula (4a)).

[0141] Next, the molecular length L4 in the direction D2 of the compound represented by the above formula (4a) is calculated. b and the carbon atom of the substituent R d The longest distance L between the carbon atoms of 4x " is the above-mentioned R 2b and R 4b As described above, in the group (x-2) of the group (2X), there are a plurality of terminal carbon atoms, and the longest distance between the terminal carbon atoms is referred to as the "substituent R band the carbon atom of the substituent R d The longest distance L between the carbon atoms of 4x " (for the compound of formula (4a), this is 22.97062 Å).

[0142] The compound represented by the above formula (4a) contains a substituent X other than a hydrogen atom. 2 and X 4 Therefore, "substituent X" does not exist. 2 is a group other than a hydrogen atom, the substituent X 2 and the carbon atom bonded to the substituent X 2 The longest distance L between the carbon atoms of 4y " and "Substituent X 4 is a group other than a hydrogen atom, the substituent X 4 and the carbon atom bonded to the substituent X 4 The longest distance L between the carbon atoms of 4z " is 0.

[0143] In this way, the "longest distance between the ends L 4x ”, “Maximum distance L between ends 4y " and "Longest distance between ends L 4z " are calculated and added together to calculate the molecular length L4 (23.0 Å for the compound of formula (4a)).

[0144] When the compound of formula (1) according to the present invention is represented by formula (3), the molecular lengths L1 and L2 correspond to the molecular lengths L5 and L6, and are defined as follows: In the compound of formula (3), the direction D1 is the direction of the substituent R 5 From the substituent R 7 The direction D2 corresponds to the direction connecting the substituent R 6 From the substituent R 8 This corresponds to the direction connecting these two points (hereinafter referred to as direction D2).

[0145]

number

[0146] The compound represented by the above formula (4a) is a compound represented by the formula (3) in which one R5 is a tert-butyl group, and four R 5 is a hydrogen atom, and two R 6 is a tert-butyl group, and three R 6 is a hydrogen atom and one R 7 is a tert-butyl group, and four R 7 is a hydrogen atom, and two R 8 is a tert-butyl group, and three R 8 is a hydrogen atom, and one Y 1 is a tert-butyl group, and two Y 1 are hydrogen atoms, and three Y 2 is a hydrogen atom, and one Y 3 is a tert-butyl group, and two Y 3 are hydrogen atoms, and three Y 4 is a hydrogen atom. The definitions of the molecular lengths L5 and L6 of the compound represented by formula (3) will be explained below. For convenience, the substituents (R 1b and R 3b ;R 1d and R 3d ; and R 2b and R 4b ) will be used to explain.

[0147] In the compound represented by the formula (4a), first, the molecular length L5 in the direction D1 is calculated. 5 and the carbon atom of the substituent R 7 The longest distance L between the carbon atoms of 5x " is the above-mentioned R 1b and R 3b As described above, there are multiple terminal carbon atoms in the group (x-1) (p-tert-butylphenyl group) of the group (2X), and the longest distance between the terminal carbon atoms is referred to as the "substituent R 5 and the carbon atom of the substituent R 7 The longest distance L between the carbon atoms of 5x " (for the compound of formula (4a), this is 23.1254 Å).

[0148] The compound represented by the above formula (4a) contains a substituent Y other than a hydrogen atom. 1 (tert-butyl group) exists. Therefore, next, "substituent Y 1 is a group other than a hydrogen atom, the substituent Y 1 and the carbon atom bonded to the substituent Y 1 The longest distance L between the carbon atoms of 5y In the compound represented by the above formula (4a), the "longest terminal-to-terminal distance L 5y " is "substituent R 1d (tert-butyl group) and the carbon atom bonded to the substituent R 1d The longest distance between the carbon atom of the substituent Y (tert-butyl group) and the terminal of the substituent Y (in the compound of formula (4a), it is 2.57896 Å). 3 (tert-butyl group) exists. Therefore, next, "substituent Y 3 is a group other than a hydrogen atom, the substituent Y 3 and the carbon atom bonded to the substituent Y 3 The longest distance L between the carbon atoms of 5z In the compound represented by the above formula (4a), the "longest terminal-to-terminal distance L 5z " is "substituent R 3d and the carbon atom bonded to the substituent R 3d The longest distance between the carbon atom of and the terminal of corresponds to this (in the compound of formula (4a), it is 2.57888 Å).

[0149] In this way, the "longest distance between the ends L 5x ”, “Maximum distance L between ends 5y " and "Longest distance between ends L 5z " are calculated and added together to calculate the molecular length L5 (28.3 Å for the compound of formula (4a)).

[0150] Next, the molecular length L4 in the direction D2 of the compound represented by the above formula (4a) is calculated. 6 and the carbon atom of the substituent R 8The longest distance L between the carbon atoms of 6x " is the above-mentioned R 2b and R 4b As described above, in the group (x-2) of the group (2X), there are a plurality of terminal carbon atoms, and the longest distance between the terminal carbon atoms is referred to as the "substituent R 6 and the carbon atom of the substituent R 8 The longest distance L between the carbon atoms of 6x " (for the compound of formula (4a), this is 22.97062 Å).

[0151] The compound represented by the above formula (4a) contains a substituent Y other than a hydrogen atom. 2 and Y 4 Therefore, "substituent Y 2 is a group other than a hydrogen atom, the substituent Y 2 and the carbon atom bonded to the substituent Y 2 The longest distance L between the carbon atoms of 6y " and "Substituent Y 4 is a group other than a hydrogen atom, the substituent Y 4 and the carbon atom bonded to the substituent Y 4 The longest distance L between the carbon atoms of 6z " is 0.

[0152] In this way, the "longest distance between the ends L 6x ”, “Maximum distance L between ends 6y " and "Longest distance between ends L 6z " are calculated and added together to calculate the molecular length L6 (23.0 Å for the compound of formula (4a)).

[0153] The molecular lengths L3 and L4, and the molecular lengths L5 and L6 thus obtained preferably have the same relationship as the molecular lengths L1 and L2. That is, the molecular lengths L3 and L4, and the molecular lengths L5 and L6 are preferably 18 Å or greater, more preferably 19 Å or greater, even more preferably 20 Å or greater, particularly preferably 21 Å or greater, and most preferably 22 Å or greater. The upper limits of the molecular lengths L1 and L2 are preferably 37 Å or less, more preferably 36 Å or less, and even more preferably 35 Å or less.

[0154] The product of the molecular length L3 and the molecular length L4 and the product of the molecular length L5 and the molecular length L6 are 500 Å. 2 More than 1180Å 2 Preferably, it is 520 Å or less. 2 Over 1150Å 2 More preferably, it is 550 Å or less. 2 More than 1140Å 2 More preferably, it is 580 Å or less. 2 More than 1135Å 2 It is particularly preferred that the thickness is 600 Å or less. 2 More than 1130Å 2 Most preferably, it is:

[0155] According to one embodiment, the molecular length L3 and the molecular length L4 are 18 Å or more and 38 Å or less, and the product of the molecular length L3 and the molecular length L4 is 500 Å or less. 2 More than 1180Å 2 According to one embodiment, the molecular length L3 and the molecular length L4 are 20 Å or more and 38 Å or less, and the product of the molecular length L3 and the molecular length L4 is 520 Å or less. 2 More than 1180Å 2 According to one embodiment, the molecular length L3 and the molecular length L4 are 21 Å or more and 31 Å or less, and the product of the molecular length L3 and the molecular length L4 is 490 Å or less. 2 More than 650Å 2 The following is the result.

[0156] According to one embodiment, the molecular length L5 and the molecular length L6 are 18 Å or more and 38 Å or less, and the product of the molecular length L5 and the molecular length L6 is 500 Å or less. 2 More than 1180Å 2 According to one embodiment, the molecular length L5 and the molecular length L6 are 20 Å or more and 38 Å or less, and the product of the molecular length L5 and the molecular length L6 is 520 Å or less. 2 More than 1180Å 2 According to one embodiment, the molecular length L5 and the molecular length L6 are 21 Å or more and 31 Å or less, and the product of the molecular length L5 and the molecular length L6 is 490 Å or less. 2 More than 650Å 2 The following is the result.

[0157] When calculating the molecular lengths L3 and L4 and the molecular lengths L5 and L6 as described above, the structure of the compound of formula (2) or (3) according to the present invention is the most stable structure calculated by density functional theory (DFT) using Gaussian 16 (Gaussian Inc.) as calculation software. After calculating the most stable structure using Gaussian 16 (Gaussian Inc.), the molecular lengths L3 to L6 of the compound can also be calculated using software such as Gauss View, Chem 3D, and IQmol.

[0158] Furthermore, when the compound of formula (1) according to the present invention is represented by formula (4), the molecular length L1 and the molecular length L2 correspond to the molecular length L7 and the molecular length L8 defined below.

[0159]

number

[0160] For the method of calculating the molecular lengths L7 and L8, the explanation of the method of calculating the molecular lengths L1 and L2 can be referred to.

[0161] When calculating the molecular lengths L7 and L8, the structure of the compound of formula (4) according to the present invention is the most stable structure calculated by density functional theory (DFT) using Gaussian 16 (Gaussian Inc.) as calculation software. After calculating the most stable structure using Gaussian 16 (Gaussian Inc.), the molecular lengths L7 and L8 of the compound can also be calculated using software such as Gauss View, Chem 3D, and IQmol.

[0162] The two axial directions in the compound represented by formula (4) are: direction D1, which is the direction of the substituent R 1a ~R 1d From the substituent R 3a ~R 3d The direction D2 corresponds to the direction connecting the substituent R 2a ~R 2d From the substituent R 4a ~R 4d This corresponds to the direction connecting these two points (hereinafter referred to as direction D2).

[0163] Molecular lengths L7 and L8 preferably have the same relationship as molecular lengths L1 and L2. That is, molecular lengths L7 and L8 are preferably 18 Å or more, more preferably 19 Å or more, even more preferably 20 Å or more, particularly preferably 21 Å or more, and most preferably 22 Å or more. The upper limits of molecular lengths L1 and L2 are preferably 37 Å or less, more preferably 36 Å or less, and even more preferably 35 Å or less.

[0164] The product of the molecular length L7 and the molecular length L8 is 500 Å. 2 More than 1180Å 2 Preferably, it is 520 Å or less. 2 Over 1150Å 2 More preferably, it is 550 Å or less. 2 More than 1140Å 2 More preferably, it is 580 Å or less. 2More than 1135Å 2 It is particularly preferred that the thickness is 600 Å or less. 2 More than 1130Å 2 Most preferably, it is:

[0165] According to one embodiment, the molecular length L7 and the molecular length L8 are 18 Å or more and 38 Å or less, and the product of the molecular length L7 and the molecular length L8 is 500 Å or less. 2 More than 1180Å 2 According to one embodiment, the molecular length L7 and the molecular length L8 are 20 Å or more and 38 Å or less, and the product of the molecular length L7 and the molecular length L8 is 520 Å or less. 2 More than 1180Å 2 According to one embodiment, the molecular length L7 and the molecular length L8 are 21 Å or more and 31 Å or less, and the product of the molecular length L7 and the molecular length L8 is 490 Å or less. 2 More than 650Å 2 The following is the result.

[0166] [Transition dipole moment orientation degree TDO] In a preferred embodiment of the present invention, the transition dipole moment of the compound of the present invention contained in the thin film formed on the substrate is 90% or more and 100% or less. If the transition dipole moment of the compound in the thin film is less than 90%, the light extraction efficiency and device efficiency will decrease. Note that although the upper limit of the transition dipole moment orientation degree (TDO) of the compound in the thin film is 100%, when the transition dipole moment orientation degree (TDO) of the compound in the thin film is calculated using the relationship of the present invention, it may exceed 100% in calculation. In this case, the transition dipole moment of the compound is considered to be 100%. According to one embodiment, the transition dipole moment orientation degree (TDO) of the compound of the present invention contained in the thin film formed on the substrate is greater than 90%. Furthermore, the transition dipole moment orientation degree (TDO) of the compound of the present invention contained in the thin film formed on the substrate is preferably 91% or more, more preferably 92% or more, even more preferably 93% or more, particularly preferably 94% or more, and most preferably 95% or more. The upper limit of the transition dipole moment orientation degree (TDO) of the compound of the present invention contained in the thin film formed on the substrate is 100%, and it can be 100% or less. According to one embodiment, the transition dipole moment orientation degree (TDO) of the compound of the present invention contained in the thin film formed on the substrate is, for example, 99% or less, or 98% or less. If the transition dipole moment of the compound of the present invention contained in the thin film formed on the substrate is within the above range, the light extraction efficiency can be further improved by the light-emitting layer containing the compound, thereby enabling an organic EL device with further improved luminous efficiency.

[0167] In the present invention, the transition dipole moment orientation degree (TDO) of the compound represented by formula (1) in a thin film is a value calculated by measuring angle-resolved photoluminescence (PL) using a Luxol OLED Analyzer from CoCoLink Corp. In detail, a 100% by mass film of the compound represented by formula (1) and 98.5% by mass of the host material is formed on a substrate (e.g., a quartz substrate) using 1.5% by mass of the compound represented by formula (1) and 98.5% by mass of the host material. -5A 50 nm-thick thin film was formed on a substrate by co-evaporation at a vacuum of 0.05 Pa and angle-resolved photoluminescence (PL) measurements were performed at room temperature (25°C) using a Luxol OLED Analyzer from CoCoLink Corp. The host materials used were compounds H-H1 and H-E1 in a mass ratio of compound H-H1:compound H-E1 = 60:40. Hereinafter, a thin film in which the compound represented by formula (1) is dispersed in the host materials, compounds H-H1 and H-E1, is also referred to as a "host-dispersed film." In other words, the transition dipole moment orientation degree (TDO) of the compound represented by formula (1) is a value that indicates the orientation state of the compound represented by formula (1) in the host-dispersed film.

[0168] [ka]

[0169] The transition dipole moment orientation degree (TDO) of a compound in a thin film calculated by angle-resolved photoluminescence (PL) measurement is defined by the following formula (i):

[0170] TDO=(Px+Py) / (Px+Py+Pz) (i) Px, Py, and Pz: The transition dipole moment components of the compounds contained in the thin film when the transition dipole moment is angularly resolved along the x, y, and z axes.

[0171] Formula (i) can be derived from the sum of the squares of the transition dipole moment of a compound contained in a thin film formed on a substrate, where the transition dipole moment is angularly resolved along the x-axis and y-axis, which are in-plane directions of the substrate, and along the y-axis, which is perpendicular to the substrate, and the moment components corresponding to the x-axis, y-axis, and z-axis are designated as Px, Py, and Pz. For a detailed explanation of the calculation of formula (i), see PHYS. REV. APPLIED 8,037001(2017).

[0172] When the transition dipole moment orientation degree (TDO) of the compound in the thin film calculated by formula (i) is 67%, it indicates that the compound is randomly arranged, and when the transition dipole moment orientation degree (TDO) of the compound in the thin film is 100%, it indicates that the compound is oriented horizontally with respect to the substrate.

[0173] [Correlation between molecular length in two directions and TDO] According to the present invention, compounds exhibiting a high transition dipole moment orientation degree (TDO) can be designed and synthesized by calculating the molecular length of the compound from the results of simulations using DFT calculations. The inventors have found that, for a compound represented by formula (1), the molecular length correlates with the transition dipole moment orientation degree (TDO) of the compound (the "relationship of the present invention"). Furthermore, for compounds represented by formulas (2) and (3), the molecular length also correlates with the transition dipole moment orientation degree (TDO) of the compound (i.e., the "relationship of the present invention" exists). That is, when designing a molecule to obtain a highly efficient compound, it has been found that by changing the molecular length of the compound, a compound having a desired transition dipole moment orientation degree (TDO) can be obtained (i.e., the relationship of the present invention exists). Therefore, for a compound represented by formula (1), the transition dipole moment (TDO) can be controlled by appropriately selecting the molecular length of the compound (the type and position of the substituent). As a result, a compound whose emission spectrum peak wavelength is in the blue wavelength region and which can achieve highly efficient emission can be selectively obtained.

[0174] The methods for calculating the molecular length L1 and molecular length L2 of the compound represented by formula (1) in the correlation of the present invention, the molecular length L3 and molecular length L4 of the compound represented by formula (2) in the correlation of the present invention, the molecular length L5 and molecular length L6 of the compound represented by formula (3) in the correlation of the present invention, and the molecular length L7 and molecular length L8 of the compound represented by formula (4) in the correlation of the present invention are as described above.

[0175] Based on the calculated molecular lengths L1 and L2, molecular lengths L3 and L4, or molecular lengths L5 and L6, the transition dipole moment orientation degree TDO of the compound can be calculated using the correlation of the present invention. Specifically, the predicted TDO (%) is calculated based on the multiplication of L1 and L2 (L1 × L2), the multiplication of L3 and L4 (L3 × L4), the multiplication of L5 and L6 (L5 × L6), or the multiplication of L7 and L8 (L7 × L8) by comparing the molecular length of the compound with the correlation (the relationship of the present invention) between the transition dipole moment orientation degree TDO of the compound. Note that this embodiment may further include determining the correlation (the relationship of the present invention) between the molecular length of the compound and the transition dipole moment orientation degree TDO of the compound. This correlation can be determined by conducting a preliminary experiment in which the transition dipole moment orientation degree (TDO) of a desired compound is measured by varying the molecular length of the compound to obtain compounds with various molecular lengths, and then measuring the transition dipole moment orientation degrees (TDO) of these compounds using a known regression analysis method such as the ordinary least squares (OLS). The specific expression of the "relationship of the present invention" determined by a known regression analysis method is not particularly limited, and may be, for example, an approximated straight line (linear regression) or an approximated curve (polynomial approximation). Furthermore, the degree of the approximated curve (polynomial approximation) is also not particularly limited, but is preferably 2- to 5-degree, and more preferably 3- to 4-degree. These approximated straight lines and approximated curves can be obtained using the "linear approximation" or "polynomial approximation" functions in the "formatting approximate curve" section of Microsoft Excel (manufactured by Microsoft Corporation). Furthermore, if a "relationship of the present invention" determined separately by such a method is available, it can also be used to carry out the production method of the present embodiment. In this case, the production method of the present embodiment does not involve determining the "relationship of the present invention." The transition dipole moment of the target compound can be appropriately set within the range of 90% to 100%. For example, the transition dipole moment of the target compound is 90% to 100%.

[0176] According to one embodiment of the present invention, a compound of the following formula (1):

[0177] [ka]

[0178] In formula (1), R 1 ~R 4 are each independently the following (1a) to (1d): (1a) a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms; (1b) a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms; (1c) a substituted or unsubstituted aromatic hydrocarbon group; or (1d) substituted or unsubstituted heterocyclic groups; and n1 to n4 are each independently 1, 2, 3, or 4, and when n1 is 2 or more, each R 1 may be the same or different, and when n2 is 2 or more, each R 2 may be the same or different, and when n3 is 2 or more, each R 3 may be the same or different, and when n4 is 2 or more, each R 4 may be the same or different; The compound has a transition dipole moment orientation degree TDO in a thin film, which is expressed by the following formula and calculated according to the following definition, of 90% or more and 100% or less.

[0179] TDO=(Px+Py) / (Px+Py+Pz) (i) Px, Py, and Pz: The transition dipole moment components of the compound contained in the thin film when angularly resolved along the x, y, and z axes; Here, the thin film is a film formed by using 1.5 mass % of the compound represented by formula (1) and 98.5 mass % of the host, based on the total mass (100 mass %) of the compound represented by formula (1) and the host material. -5A 50-nm-thick thin film was formed on a substrate by co-evaporation at a vacuum of 100 Pa. The host material was a mixture of Compound H-H1 and Compound H-E1 in a mass ratio of Compound H-H1:Compound H-E1=60:40.

[0180] [ka]

[0181] According to one embodiment of the present invention, a compound represented by the following formula (2):

[0182] [ka]

[0183] In equation (2), A a ~A d are each independently a benzene ring or a heterocycle, R a ~R d each independently represents a hydrogen atom, an unsubstituted alkyl group having from 1 to 20 carbon atoms, an unsubstituted alkoxy group having from 1 to 20 carbon atoms, an unsubstituted arylamino group having from 6 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted aromatic heterocyclic group; na is A a is a benzene ring, then 5, and A a When is a heterocycle, A a is the upper limit of the number of substitutions that can be made into nb is A b is a benzene ring, then 5, and A b When is a heterocycle, A b is the upper limit of the number of substitutions that can be made into nc is A c is a benzene ring, then 5, and A c When is a heterocycle, A c is the upper limit of the number of substitutions that can be made into nd is A d is a benzene ring, then 5, and A dWhen is a heterocycle, A d is the upper limit of the number of substitutions that can be made into X 1 ~X 4 are each independently a hydrogen atom, an unsubstituted alkyl group having from 1 to 20 carbon atoms, an unsubstituted alkoxy group having from 1 to 20 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group, m1 to m4 are 3; The compound has a transition dipole moment orientation degree TDO in a thin film, which is expressed by the following formula and calculated according to the following definition, of 90% or more and 100% or less.

[0184] TDO=(Px+Py) / (Px+Py+Pz) (i) Px, Py, and Pz: The transition dipole moment components of the compound contained in the thin film when angularly resolved along the x, y, and z axes; Here, the thin film is a film formed by using 1.5 mass % of the compound represented by formula (2) and 98.5 mass % of the host, based on the total mass (100 mass %) of the compound represented by formula (2) and the host material, and -5 A 50-nm-thick thin film was formed on a substrate by co-evaporation at a vacuum of 100 Pa. The host material was a mixture of Compound H-H1 and Compound H-E1 in a mass ratio of Compound H-H1:Compound H-E1=60:40.

[0185] According to one embodiment of the present invention, a compound represented by the following formula (3):

[0186] [ka]

[0187] In equation (3), R 5 ~R 8 are each independently a hydrogen atom, an unsubstituted alkyl group having from 1 to 20 carbon atoms, an unsubstituted alkoxy group having from 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted aromatic heterocyclic group, n5 to n8 are 5, Y 1 ~Y 4 are each independently a hydrogen atom, an unsubstituted alkyl group having from 1 to 20 carbon atoms, an unsubstituted alkoxy group having from 1 to 20 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group, ng~nj is 3; The compound has a transition dipole moment orientation degree TDO in a thin film, which is expressed by the following formula and calculated according to the following definition, of 90% or more and 100% or less.

[0188] TDO=(Px+Py) / (Px+Py+Pz) (i) Px, Py, and Pz: The transition dipole moment components of the compound contained in the thin film when angularly resolved along the x, y, and z axes; Here, the thin film is a film formed by using 1.5 mass % of the compound represented by formula (3) and 98.5 mass % of the host, based on the total mass (100 mass %) of the compound represented by formula (3) and the host material. -5 A 50-nm-thick thin film was formed on a substrate by co-evaporation at a vacuum of 100 Pa. The host material was a mixture of Compound H-H1 and Compound H-E1 in a mass ratio of Compound H-H1:Compound H-E1=60:40.

[0189] According to one embodiment of the present invention, a compound represented by the following formula (4):

[0190] [ka]

[0191] In equation (4), R 1a ~R 1d , R 2a ~R 2d , R 3a ~R 3d and R 4a ~R 4d are each independently a hydrogen atom or the following group (1X):

[0192] [ka]

[0193] is a group selected from In this case, R 1a ~R 1d At least one of R 2a ~R 2d At least one of R 3a ~R 3d At least one of, and R 4a ~R 4d at least one of the is a group selected from the group (1X) (note that * in the group (1X) represents a binding site); The compound has a transition dipole moment orientation degree TDO in a thin film, which is expressed by the following formula and calculated according to the following definition, of 90% or more and 100% or less.

[0194] TDO=(Px+Py) / (Px+Py+Pz) (i) Px, Py, and Pz: The transition dipole moment components of the compound contained in the thin film when angularly resolved along the x, y, and z axes; Here, the thin film is a film formed by using 1.5 mass % of the compound represented by formula (4) and 98.5 mass % of the host, based on the total mass (100 mass %) of the compound represented by formula (4) and the host material. -5 A 50-nm-thick thin film was formed on a substrate by co-evaporation at a vacuum of 100 Pa. The host material was a mixture of Compound H-H1 and Compound H-E1 in a mass ratio of Compound H-H1:Compound H-E1=60:40.

[0195] Specific examples of the compound of formula (1) according to one embodiment of the present invention are given below. However, the present invention is not limited to these specific examples. For example, the compound of formula (1) according to one embodiment of the present invention includes the following compounds (101) to (141).

[0196] [ka]

[0197] [ka]

[0198] [ka]

[0199] Preferred compounds include, for example, the above-mentioned compounds 101, 105, 110, 119, 135, 136, 140, and the like.

[0200] [Light Emitting Properties] The compound of formula (1) according to the present invention can realize light emission with a peak wavelength in the blue wavelength region of the emission spectrum and high color purity. In the present specification, the blue wavelength region refers to a wavelength range of 400 nm to 500 nm. The peak wavelength of photoluminescence (PL) emission of the compound of formula (1) according to the present invention is not particularly limited, but is preferably in the range of 440 nm to 480 nm. Furthermore, the peak wavelength preferably has a peak in the wavelength range of 445 nm to 470 nm, more preferably 450 nm to 470 nm, and particularly preferably 450 nm to 465 nm. When the peak wavelength is within the above range, good light emission, particularly good blue light emission, can be obtained. The peak wavelength of PL emission can be measured using a spectrofluorometer F-7000 manufactured by Hitachi High-Technologies Corporation. More specifically, when 1×10 -5 M (=mol / dm 3 The evaluation can be performed by measuring a toluene solution of the compound of formula (1) according to the present invention and a host molecule (mol / L) in an amount of 1000 ppm or a thin film formed by evaporating the compound of formula (1) according to the present invention and a host molecule by the method described in the Examples below, using the spectrofluorometer at an excitation wavelength of 360 nm at room temperature.

[0201] [Manufacturing method] The synthesis method of the compound of formula (1) according to the present invention is not particularly limited, and the compound can be synthesized based on the knowledge of known synthesis methods. More specifically, the compound can be synthesized by the method described in the Examples or in accordance with the method described in the Examples. For example, the compound can be synthesized by changing the raw materials, reaction conditions, etc., in the method described in the Examples, adding or excluding some steps, or appropriately combining known synthesis methods.

[0202] The method for confirming the structure of the compound of formula (1) according to the present invention is not particularly limited. The structure of the compound of formula (1) according to the present invention can be confirmed by known methods (e.g., NMR, LC-MS, etc.).

[0203] <Materials for organic electroluminescence devices> Another aspect of the present invention relates to a material for an organic electroluminescence device, comprising the compound of formula (1). The material is more preferably a material for an emitting layer.

[0204] A material for an organic electroluminescence device according to one embodiment of the present invention preferably contains the compound of formula (1) and other materials used in the organic electroluminescence device. The other materials used in the organic electroluminescence device are not particularly limited, but are preferably a phosphorescent material or a host material, and more preferably a phosphorescent complex and a host material. Here, it is preferable to use the compound of formula (1) as a dopant material and a phosphorescent complex as an auxiliary dopant material. The use of the compound of formula (1) together with a phosphorescent material or a host material (preferably a phosphorescent complex and a host material) significantly improves luminous efficiency. The reason for this is presumed to be as follows: When the material for an organic electroluminescence device contains a host material, the phosphorescent material receives energy from the host material. The phosphorescent material then transfers energy to the compound of formula (1) via a FRET (Fluorescence Resonance Energy Transfer) mechanism. As a result, highly efficient energy transfer occurs from the phosphorescent material to the compound of formula (1). Other materials used in the organic electroluminescent device may also be other materials known in the art.

[0205] The content of the compound of formula (1) relative to the total mass of the materials for organic electroluminescence devices (particularly, materials for the light-emitting layer) is not particularly limited, but is preferably 0.05% by mass or more. The content is more preferably 0.1% by mass or more, and even more preferably 0.2% by mass or more. Within this range, an organic electroluminescence device with excellent color purity of emitted light and high luminous efficiency can be obtained. The content of the compound of formula (1) relative to the total mass of the materials for organic electroluminescence devices (particularly, materials for the light-emitting layer) is not particularly limited, but is preferably 50% by mass or less. The content is more preferably 30% by mass or less, and even more preferably 25% by mass or less. Within this range, an organic electroluminescence device with excellent color purity of emitted light and high luminous efficiency can be obtained. The preferred content of the compound of formula (1) relative to the total mass of the light-emitting layer of an organic electroluminescence device, which will be described later, is also the same as above.

[0206] (phosphorescent complex) The material for an organic electroluminescence device according to one embodiment of the present invention preferably further contains a phosphorescent complex in addition to the compound of formula (1). The inclusion of the phosphorescent complex significantly improves the luminous efficiency. The use of the compound of formula (1) together with the phosphorescent complex significantly improves the luminous efficiency. The reason for this is presumed to be as follows: The phosphorescent complex transfers energy to the compound of formula (1) via a FRET (Fluorescence Resonance Energy Transfer) mechanism. As a result, highly efficient energy transfer occurs from the phosphorescent complex to the nitrogen-containing fused ring compound. It is presumed that the above-mentioned effects are achieved because highly efficient energy transfer is possible from the phosphorescent complex to the compound of formula (1).

[0207] The phosphorescent complex is not particularly limited, but is preferably a metal complex from the viewpoint of luminous efficiency. From the same viewpoint, a platinum complex or a palladium complex is more preferable, and a platinum complex is even more preferable. Therefore, in the material for an organic electroluminescence device according to a preferred embodiment of the present invention, for example, the phosphorescent complex is a platinum complex.

[0208] The phosphorescent complex is not particularly limited, but from the viewpoint of color purity and luminous efficiency of emitted light, a compound having a structure of the following formula (5) is a preferred example.

[0209] [ka]

[0210] In the above formula (5), M is a metal ion with a coordination number of 4, R 41 , R 42 , R 43 , and R 44 are each independently a substituted or unsubstituted hydrocarbon ring group or a substituted or unsubstituted heterocyclic group, L 41 is R 41 and R 42 is a linking group connecting L 42 is R 42 and R 43 is a linking group connecting L 43 is R 43 and R 44 is a linking group that links

[0211] In the above formula (5), the hydrocarbon ring group represents a group derived from one or more hydrocarbon rings. When the hydrocarbon ring group contains two or more hydrocarbon rings, some or all of these rings may be bonded to each other via single bonds or fused together. Furthermore, when the hydrocarbon ring group contains two or more hydrocarbon rings, one atom may also serve as a ring-forming atom for any of these rings.

[0212] In the above formula (5), the heterocyclic group is the same as the monovalent heterocyclic group described in the description of the group (1d) in the above formula (1), except that the valence may be different.

[0213] The substituent that substitutes the hydrocarbon ring group or heterocyclic group in the above formula (5) is not particularly limited, but is preferably one of the substituents exemplified as the substituents that substitute the groups (1a) to (1d) in the above formula (1).

[0214] In the above formula (5), M is a platinum (Pt) ion or a palladium (Pd) ion. Preferably, the ion is a platinum (Pt) ion, and more preferably, a platinum (Pt) ion.

[0215] Known compounds may be used as the phosphorescent complex. For example, see "Tyler Fleetham et al., Effective "Pure" Blue OLEDs Employing Tetradentate Pt Complexes with a Narrow Spectral Bandwidth”, Advanced Materials, 2014, 26, 7116-7121, the platinum complexes described in European Patent Application Publication No. 3670520, the platinum complexes and palladium complexes described in Japanese Patent Application Publication No. 2019-029500, and the platinum complexes described in U.S. Patent Application Publication No. 2015 / 0162552 may also be used.

[0216] Specific examples of phosphorescent complexes according to one embodiment of the present invention are given below, but the present invention is not limited to these specific examples.

[0217] [ka]

[0218] [ka]

[0219]

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[0220]

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[0221]

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[0222]

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[0224]

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[0225]

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[0226]

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[0227] The content of the phosphorescent complex relative to the total mass of the materials for organic electroluminescence devices (particularly, materials for the light-emitting layer) is not particularly limited, but is preferably 0.1% by mass or more, more preferably 0.2% by mass or more. The content is more preferably 0.5% by mass or more, even more preferably 1% by mass or more. The content is particularly preferably 3% by mass or more, even more preferably 5% by mass or more. Within this range, an organic electroluminescence device with excellent color purity of emitted light and high luminous efficiency can be obtained. The content of the phosphorescent complex relative to the total mass of the materials for organic electroluminescence devices (particularly, materials for the light-emitting layer) is not particularly limited, but is preferably 50% by mass or less. The content is more preferably 40% by mass or less, even more preferably 30% by mass or less. Within this range, an organic electroluminescence device with excellent color purity of emitted light and high luminous efficiency can be obtained. The preferred content of the phosphorescent complex relative to the total mass of the light-emitting layer of the organic electroluminescence device, which will be described later, is the same as above.

[0228] When the material for an organic electroluminescence device (particularly, the material for an emitting layer) contains a phosphorescent complex, the content thereof is preferably 100 parts by mass or more relative to 100 parts by mass of the compound of formula (1). Furthermore, the content is more preferably 150 parts by mass or more, and even more preferably 200 parts by mass or more, relative to 100 parts by mass of the compound of formula (1). Within this range, an organic electroluminescence device having excellent color purity of emitted light and high luminous efficiency can be obtained. Furthermore, the content of the phosphorescent complex is not particularly limited, but is preferably 10,000 parts by mass or less relative to 100 parts by mass of the compound of formula (1). Furthermore, the content is more preferably 7,500 parts by mass or less, and even more preferably 5,000 parts by mass or less, relative to 100 parts by mass of the compound of formula (1). Within this range, an organic electroluminescence device having excellent color purity of emitted light and high luminous efficiency can be obtained. The preferred content (parts by mass) of the phosphorescent complex relative to 100 parts by mass of the compound of the above formula (1) in the light-emitting layer of the organic electroluminescence device described below is also the same as above.

[0229] (host material) The material for an organic electroluminescence device according to one embodiment of the present invention preferably further contains a host material in addition to the compound of formula (1). By using the compound of formula (1) as a dopant material in combination with the host material, excellent luminous efficiency can be achieved in the organic electroluminescence device.

[0230] The host material is not particularly limited and can be a known host material. For example, the known host material may be an anthracene derivative, a pyrene derivative, a fluoranthene derivative, a chrysene derivative, a dihydrobenzoanthracene derivative, or a triphenylene derivative. As the anthracene derivative, 9-(1-naphthyl)-10-(2-naphthyl)anthracene (compound HT4 shown below) is preferably used.

[0231] [ka]

[0232] Preferred examples of the host material include compounds having a carbazole ring structure (excluding compounds represented by the above formula (1)), compounds having a ring structure in which one or more ring-forming carbon atoms of the carbazole ring are substituted with nitrogen atoms (excluding compounds represented by the above formula (1) and compounds having the above carbazole ring structure), and compounds having a triazine ring structure (excluding compounds represented by the above formula (1), compounds having the above carbazole ring structure, and compounds having a ring structure in which one or more ring-forming carbon atoms of the carbazole ring are substituted with nitrogen atoms). Among these, compounds having a carbazole ring structure are more preferred. Use of these compounds as host materials can promote efficient energy transfer within the light-emitting layer. Furthermore, the balance of carrier mobility between electrons and holes can be further improved. In the carbazole ring structure, the ring structure in which one or more ring-forming carbon atoms of the carbazole ring are substituted with nitrogen atoms, and the triazine ring structure in these compounds, hydrogen atoms bonded to the ring-forming atoms of these rings may be substituted with other atoms or substituents. In addition, two or more of these substituents may form a ring structure.

[0233] The compound having the above-mentioned carbazole ring structure or the compound having a ring structure in which one or more ring-forming carbon atoms of the above-mentioned carbazole ring are substituted with a nitrogen atom is not particularly limited, but a compound having a structure represented by the following formula (6) is preferred.

[0234] [ka]

[0235] In the above formula (6), Z 51 , CH, CR 51 or N, Z 52 , CH, CR 52 or N, Z 53 , CH, CR 53 or N, Z 54 , CH, CR 54 or N, Z 55 , CH, CR 55 or N, Z 56 , CH, CR 56 or N, Z 57 , CH, CR 57 or N, Z 58 , CH, CR 58 or N, R 51 ~R 58 are each independently any one of the following groups (6a) to (6h): (6a) a cyano group (-CN group), (6b) a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms; (6c) a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, (6d) a substituted or unsubstituted arylamino group having 6 to 20 carbon atoms, (6e) a substituted or unsubstituted phosphoryl group (-POH2 group); (6f) substituted or unsubstituted silyl groups (-SiH3 groups); (6g) a substituted or unsubstituted monovalent aromatic hydrocarbon group, (6h) a substituted or unsubstituted monovalent heterocyclic group, Ar 51 is a group containing at least one of an aromatic hydrocarbon group and a heterocyclic group, m is 1, 2, 3, 4, 5 or 6; Here, the R 51 and the above R 52 , the R 52 and the above R 53 , the R 53 and the above R 54 , the R 55 and the above R 56 , the R56 and the above R 57 , or the R 57 and the above R 58 may form an aliphatic hydrocarbon ring, an aromatic hydrocarbon ring, or a heterocyclic ring containing the carbon atoms to which they are attached.

[0236] In the formula (6), the explanations of the groups (6b), (6c), (6g) and (6h) are the same as the explanations of the groups (1a) to (1d) in the formula (1). In addition, in the formula (6), the explanation of the group (6d) is the same as the explanation of the R 1 ~R 4 The substituents which may be possessed by the arylamino group are the same as those of the arylamino group.

[0237] Also, Ar 51 In the above, the aromatic hydrocarbon group is the same as the aromatic hydrocarbon group described in the explanation of the group (1c) in the above formula (1), except that the valence may be different.

[0238] And Ar 51 In the above, the heterocyclic group is the same as the heterocyclic group described in the explanation of the group (1d) in the above formula (1), except that the valence may be different.

[0239] In the above formula (6), Z 51 ~Z 58 It is preferable that not all of Z are N or only one of Z is N. 51 ~Z 58 It is more preferable that all of the s are not N.

[0240] In the formula (6), when the groups (6b) to (6h) are substituted, the substituents substituting these groups are not particularly limited, and may be, for example, the groups (6a) to (6h). Specific examples of substituents substituting these groups include, but are not limited to, a cyano group, an unsubstituted alkyl group having from 1 to 20 carbon atoms, an alkoxy group having from 1 to 20 carbon atoms substituted with an aromatic hydrocarbon group having from 6 to 30 carbon atoms which is further substituted with an unsubstituted alkenyl group having from 2 to 30 carbon atoms, a substituted or unsubstituted arylamino group having from 6 to 20 carbon atoms, an unsubstituted aromatic hydrocarbon group having from 6 to 30 carbon atoms, an aromatic hydrocarbon group having from 6 to 30 carbon atoms substituted with a cyano group, an aromatic hydrocarbon group having from 6 to 30 carbon atoms substituted with an unsubstituted alkenyl group having from 2 to 30 carbon atoms, an aromatic hydrocarbon group having from 6 to 30 carbon atoms substituted with an unsubstituted arylamino group having from 6 to 20 carbon atoms, an unsubstituted heterocyclic group having from 3 to 30 ring atoms, and a heterocyclic group having from 3 to 30 ring atoms substituted with an unsubstituted aromatic hydrocarbon group having from 6 to 30 carbon atoms.

[0241] In the above formula (6), Ar 51 is not particularly limited as long as it is at least one of an aromatic hydrocarbon group and a heterocyclic group. Examples thereof include a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted heterocyclic group, a group in which one or more substituted or unsubstituted aromatic hydrocarbon groups and one or more substituted or unsubstituted heterocyclic groups are bonded via a single bond, and a group in which two or more substituted or unsubstituted aromatic hydrocarbon groups or substituted or unsubstituted heterocyclic groups are bonded via a linking group other than these groups.

[0242] In the group in which two or more substituted or unsubstituted aromatic hydrocarbon groups or substituted or unsubstituted heterocyclic groups are bonded via a linking group other than these groups, the linking group is not particularly limited, and specific examples include a Si group, an N group, a P=O group, an S(=O)=O group, and a C=O group.

[0243] In the above formula (6), Ar 51 When the groups constituting the formula (I) are substituted groups, the substituents substituting these groups are not particularly limited. For example, they may be the groups (6a) to (6h) above. Specific examples of the substituents substituting these groups are not particularly limited, but include a cyano group, an unsubstituted alkyl group having 1 to 20 carbon atoms, and a monovalent heterocyclic group having 3 to 30 ring atoms substituted with an unsubstituted alkyl group having 1 to 20 carbon atoms.

[0244] Here, the substituents of the groups (6b) to (6h) above, or Ar 51 The alkyl group having 1 to 20 carbon atoms, the alkoxy group having 1 to 20 carbon atoms, the aromatic hydrocarbon group having 6 to 30 carbon atoms, and the heterocyclic group having 3 to 30 ring atoms in the substituents of the group constituting the formula (1) are the same as those described for the groups (1a) to (1d) in the formula (1). 51 The arylamino group having 6 to 20 carbon atoms in the substituent of the group constituting the formula (1) is 1 ~R 4 The substituents which may be possessed by the arylamino group are the same as those of the arylamino group.

[0245] In addition, the substituents of the groups (6c) to (6h), Ar 51 The alkenyl group having 2 to 30 carbon atoms in the substituent of the group constituting the formula (I) is not particularly limited and may be linear, branched, or cyclic. Specific examples of the alkenyl group are not particularly limited, but include, for example, vinyl group, 2-propenyl group, 2-butenyl group, 3-butenyl group, 1-methyl-2-propenyl group, 2-methyl-2-propenyl group, 2-pentenyl group, 3-pentenyl group, 4-pentenyl group, 1-methyl-2-butenyl group, 2-methyl-2-butenyl group, 3-methyl-2-butenyl group, 1-methyl-3-butenyl group, 2-methyl-3-butenyl group, 3-methyl-3-butenyl group, 1,1-dimethyl-2-propenyl group, 1,2-dimethyl-2-propenyl group, and 1-ethyl-2-propenyl group.

[0246] m is preferably 1, 2, 3 or 4, and more preferably 2.

[0247] Specific examples of compounds having a carbazole ring structure, which are host materials according to one embodiment of the present invention, and compounds having a ring structure in which one or more ring-forming carbon atoms of the carbazole ring are substituted with nitrogen atoms are given below, but the present invention is not limited to these specific examples.

[0248] [ka]

[0249] [ka]

[0250] [ka]

[0251] [ka]

[0252] [ka]

[0253] [ka]

[0254] [ka]

[0255] [ka]

[0256] For these reasons, a preferred embodiment of the material for an organic electroluminescence device according to the present invention includes a compound of the formula (1), the phosphorescent complex, and a host material, wherein the host material includes a compound having a structure represented by the formula (6). A preferred embodiment of the organic electroluminescence device described below includes an organic electroluminescence device including a compound of the formula (1) and a host material, wherein the host material includes a compound having a structure represented by the formula (6). A preferred embodiment of the organic electroluminescence device includes a compound of the formula (1), the phosphorescent complex, and a host material, wherein the host material includes at least two compounds having a structure represented by the formula (6). In this case, for example, the compound having a structure represented by the formula (6) preferably includes the HT1 and HT2.

[0257] The compound having the triazine ring structure is not particularly limited, but is preferably a compound having a structure represented by the following formula (7).

[0258] [ka]

[0259] In the above formula (7), Ar 61 ~Ar 63 are each independently a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted heterocyclic group.

[0260] In the above formula (7), the substituted or unsubstituted aromatic hydrocarbon group is the same as that described for the group (1c) in the above formula (1), and the substituted or unsubstituted heterocyclic group is the same as that described for the group (1d) in the above formula (1).

[0261] The substituents substituting the aromatic hydrocarbon group or heterocyclic group in the formula (7) are not particularly limited, but are preferably those listed as the substituents substituting the groups (1a) to (1d) in the formula (1). Also preferred are silyl groups substituted with unsubstituted aromatic hydrocarbon groups. The unsubstituted aromatic hydrocarbon groups are the same as those described for the unsubstituted groups in the group (1c).

[0262] Among the compounds having a triazine ring structure, compounds containing a silyl group (compounds having a triazine ring structure with a silyl group) are preferred.

[0263] The compound having a triazine ring structure is preferably used in combination with the compound having the above-mentioned carbazole ring structure or the compound having a ring structure in which one or more ring-forming carbon atoms of the above-mentioned carbazole ring are substituted with a nitrogen atom.

[0264] Specific examples of compounds having a triazine ring structure that are host materials according to one embodiment of the present invention are given below, although the present invention is not limited to these specific examples.

[0265] [ka]

[0266] For these reasons, a preferred embodiment of the material for an organic electroluminescence device according to the present invention includes a compound of formula (1), the phosphorescent complex, and a host material, wherein the host material includes a compound having a structure represented by formula (6). A more preferred embodiment of the material for an organic electroluminescence device according to the present invention includes a compound of formula (1), the phosphorescent complex, and a host material, wherein the host material includes a compound having a structure represented by formula (6) and a compound having a structure represented by formula (7). A preferred embodiment of the organic electroluminescence device described below includes an organic electroluminescence device including a compound of formula (1) and a host material, wherein the host material includes a compound having a structure represented by formula (6). A more preferred embodiment of the organic electroluminescence device is an organic electroluminescence device comprising a compound of the above formula (1) and a host material, wherein the host material comprises a compound having a structure represented by the above formula (6) and a compound having a structure represented by the above formula (7).

[0267] The content of the host material relative to the total mass of the materials for organic electroluminescence devices (particularly, materials for the light-emitting layer) is not particularly limited, but is preferably 5% by mass or more. The content is more preferably 10% by mass or more, and even more preferably 20% by mass or more. Within this range, an organic electroluminescence device with excellent color purity of emitted light and high luminous efficiency can be obtained. The content of the host material relative to the total mass of the materials for organic electroluminescence devices (particularly, materials for the light-emitting layer) is not particularly limited, but is preferably 99% by mass or less. The content is more preferably 98% by mass or less, and even more preferably 95% by mass or less. Within this range, an organic electroluminescence device with excellent color purity of emitted light and high luminous efficiency can be obtained. The preferred content of the host material relative to the total mass of the light-emitting layer of the organic electroluminescence device described below is also the same as above.

[0268] When the material for an organic electroluminescence device contains a host material, the content thereof is preferably 1,000 parts by mass or more relative to 100 parts by mass of the compound of the above formula (1). The content is more preferably 2,000 parts by mass or more, and even more preferably 3,000 parts by mass or more, relative to 100 parts by mass of the compound of the above formula (1). Within this range, an organic electroluminescence device with excellent color purity of emitted light and high luminous efficiency can be obtained. The content of the host material is not particularly limited, but is preferably 200,000 parts by mass or less relative to 100 parts by mass of the compound of the above formula (1). The content is more preferably 150,000 parts by mass or less, and even more preferably 100,000 parts by mass or less, relative to 100 parts by mass of the compound of the above formula (1). Within this range, an organic electroluminescence device with excellent color purity of emitted light and high luminous efficiency can be obtained. The preferred content (parts by mass) of the host material relative to 100 parts by mass of the compound of the above formula (1) in the light-emitting layer of the organic electroluminescence device described below is also the same as above.

[0269] <Organic electroluminescence element> Another aspect of the present invention relates to an organic electroluminescent device having an emitting layer containing the compound of formula (1). In the organic electroluminescent device, the emitting layer preferably contains the compound of formula (1) and a phosphorescent complex, and more preferably contains a host material in addition to the compound of formula (1) and the phosphorescent complex. In this case, the phosphorescent complex is more preferably a platinum complex.

[0270] Another aspect of the present invention relates to an organic electroluminescence device including the material for an organic electroluminescence device. In the organic electroluminescence device, the material for an organic electroluminescence device preferably further includes the host material. In the organic electroluminescence device, the phosphorescent complex contained therein is more preferably a platinum complex.

[0271] In an organic electroluminescent device, the host material contained therein is preferably a compound having the above-mentioned carbazole ring structure, a compound having a ring structure in which one or more ring-forming carbon atoms of the above-mentioned carbazole ring are substituted with a nitrogen atom, or a compound having the above-mentioned triazine ring structure. Furthermore, in an organic electroluminescent device, the host material contained therein preferably includes a compound having a structure represented by the above-mentioned formula (6). Furthermore, in an organic electroluminescent device, the host material contained therein more preferably includes a compound having a structure represented by the above-mentioned formula (7). Furthermore, in an organic electroluminescent device, the host material contained therein more preferably includes a compound having a structure represented by the above-mentioned formula (6) and a compound having a structure represented by the above-mentioned formula (7).

[0272] In the organic electroluminescence device, the phosphorescent complex contained therein is preferably a compound having a structure represented by the above formula (5).

[0273] An organic electroluminescent device according to one embodiment of the present invention includes, but is not limited to, a first electrode, a second electrode, and one or more organic layers. The second electrode is disposed on the first electrode.

[0274] In this specification, when a layer, film, region, plate, or other portion is described as being "on" or "on top" of another portion, this includes not only the case where it is "directly above" the other portion, but also the case where there is another portion between them. Conversely, when a layer, film, region, plate, or other portion is described as being "under" or "below" the other portion, this includes not only the case where it is "directly below" the other portion, but also the case where there is another portion between them. Furthermore, in this application, being "located on" includes not only the case where it is located on the top, but also the case where it is located on the bottom or lower surface.

[0275] An organic electroluminescent device according to one embodiment of the present invention comprises a first electrode, a second electrode, and a single or multiple layers disposed between the first and second electrodes. The layers include at least one organic layer, and at least one of the organic layers contains the compound of formula (1) or the material for organic electroluminescent devices. The organic layer containing the compound of formula (1) or the material for organic electroluminescent devices preferably includes an emitting layer. These organic electroluminescent devices can achieve light emission with high color purity.

[0276] Thus, the light-emitting layer preferably comprises at least one compound of formula (1) above.

[0277] The light-emitting layer may be a single layer made of a single material, a single layer made of multiple different materials, or a multilayer structure having multiple layers made of multiple different materials.

[0278] The light-emitting layer is not particularly limited, and may contain, for example, a host material and a dopant material. The compound of formula (1) may be used as either a host material or a dopant material, but is preferably used as a dopant material.

[0279] For these reasons, a preferred embodiment of the present invention is an organic electroluminescence device including an emitting layer, the emitting layer containing the compound of formula (1) or the material for an organic electroluminescence device. It is more preferable that the emitting layer is composed of the material for an organic electroluminescence device. From the viewpoints of the peak wavelength of the emission spectrum, the color purity of the emitted light, and the luminous efficiency, it is preferable that the material for an organic electroluminescence device contains the host material in addition to the compound of formula (1). From the same viewpoint, it is more preferable that the material for an organic electroluminescence device contains the phosphorescent complex and the host material in addition to the compound of formula (1). The preferred ranges of the contents and content ratios of the compound of formula (1), the phosphorescent complex, and the host material in the emitting layer are the same as the preferred contents and content ratios in the material for an organic electroluminescence device.

[0280] The thickness of the light-emitting layer is not particularly limited, but is preferably 1 nm or more and 100 nm or less, and more preferably 10 nm or more and 50 nm or less.

[0281] The method for forming the light-emitting layer is not particularly limited, and examples thereof include known film-forming methods such as vacuum deposition, spin coating, Langmuir-Blodgett (LB) method, inkjet printing, laser printing, and laser induced thermal imaging (LITI).

[0282] The emission wavelength of the organic electroluminescence element is not particularly limited. A preferred range of the emission wavelength of the organic electroluminescence element is, for example, the same as the peak wavelength of emission in PL of the compound of formula (1) according to the present invention. Among these, from the specifications of currently commercialized products, in the case of blue light emission, it is preferable to emit light having a peak in the wavelength range of 445 nm or more and 470 nm or less, it is particularly preferable to emit light having a peak in the wavelength range of 450 nm or more and 470 nm or less, and it is extremely preferable to emit light having a peak in the wavelength range of 450 nm or more and 465 nm or less.

[0283] Hereinafter, with reference to the accompanying drawings, a detailed description will be given of an organic electroluminescent device according to one embodiment of the present invention, which further comprises an organic layer other than the light-emitting layer. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description will be omitted. Furthermore, the dimensional ratios in the drawings are exaggerated for the sake of explanation and may differ from the actual ratios.

[0284] 1 to 3 are cross-sectional views each showing an organic electroluminescence element according to one embodiment of the present invention, but the structure of the organic electroluminescence element according to the present invention is not limited to the forms shown in FIGS.

[0285] 1 is a cross-sectional view showing an organic electroluminescent device according to one embodiment of the present invention. The organic electroluminescent device 10 according to the present invention includes a substrate 1, a first electrode 2, a hole transport region 3, an emitting layer 4, an electron transport region 5, and a second electrode 6, which are stacked in this order.

[0286] Figure 2 is a cross-sectional view showing an organic electroluminescent device according to another embodiment of the present invention. An organic electroluminescent device 10 according to one embodiment of the present invention includes a substrate 1, a first electrode 2, a hole transport region 3, an emitting layer 4, an electron transport region 5, and a second electrode 6, which are stacked in this order. In Figure 2, the hole transport region 3 includes a hole injection layer 31 and a hole transport layer 32, which are stacked in this order. Also, in Figure 2, the electron transport region 5 includes an electron transport layer 52 and an electron injection layer 51, which are stacked in this order.

[0287] Figure 3 is a cross-sectional view showing an organic electroluminescent device according to another embodiment of the present invention. The organic electroluminescent device 10 according to one embodiment of the present invention includes a substrate 1, a first electrode 2, a hole transport region 3, an emitting layer 4, an electron transport region 5, and a second electrode 6, which are stacked in this order. In Figure 3, the hole transport region 3 includes a hole injection layer 31, a hole transport layer 32, and an electron blocking layer 33, which are stacked in this order. Also, in Figure 3, the electron transport region 5 includes a hole blocking layer 53, an electron transport layer 52, and an electron injection layer 51, which are stacked in this order.

[0288] The substrate, and each region and layer will be described in detail below.

[0289] (Substrate 1) The organic electroluminescent element 10 may have a substrate 1. A substrate used in a general organic electroluminescent element can be used as the substrate 1. For example, the substrate 1 may be a glass substrate, a semiconductor substrate such as a silicon substrate, or a transparent plastic substrate.

[0290] (1st electrode 2) The first electrode 2 is conductive. In an organic electroluminescent element according to one embodiment of the present invention, the first electrode 2 is preferably a positive electrode. The first electrode 2 is preferably a pixel electrode. The first electrode 2 is preferably a transmissive electrode, a semi-transmissive electrode, or a reflective electrode.

[0291] The material constituting the first electrode 2 is not particularly limited, and examples thereof include metals, metal alloys, and conductive compounds. If the first electrode 2 is a transmissive electrode, the first electrode 2 preferably contains a transparent metal oxide such as ITO (indium tin oxide), IZO (indium zinc oxide), ZnO (zinc oxide), or ITZO (indium tin zinc oxide). If the first electrode 2 is a semi-transmissive electrode or a reflective electrode, the first electrode 2 preferably contains Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, or a compound or mixture thereof (e.g., a mixture of Ag and Mg).

[0292] The first electrode 2 may be a single layer made of a single material, a single layer made of multiple different materials, or a multilayer structure having multiple layers made of multiple different materials.

[0293] The thickness of the first electrode 2 is not particularly limited, but is preferably 10 nm or more and 1000 nm or less, and more preferably 50 nm or more and 300 nm or less.

[0294] (Hole transport region 3) The hole transport region 3 is provided on the first electrode 2. The hole transport region 3 includes at least one of a hole injection layer 31, a hole transport layer 32, a hole buffer layer (not shown), and an electron blocking layer 33.

[0295] The hole transport region 3 may be a single layer made of a single material, a single layer made of multiple different materials, or a multi-layer structure having multiple layers made of multiple different materials.

[0296] For example, the hole transport region 3 may have a single layer structure of a hole injection layer 31 or a hole transport layer 32. Alternatively, for example, the hole transport region 3 may have a single layer structure formed of a hole injection material and a hole transport material. Alternatively, for example, the hole transport region 3 may have a structure of hole injection layer 31 / hole transport layer 32, which are stacked in this order from the first electrode 2. Alternatively, for example, the hole transport region 3 may have a structure of hole injection layer 31 / hole transport layer 32 / hole buffer layer (not shown). Alternatively, for example, the hole transport region 3 may have a structure of hole injection layer 31 / hole buffer layer (not shown), which are stacked in this order from the first electrode 2. Alternatively, for example, the hole transport region 3 may have a structure of hole transport layer 32 / hole buffer layer (not shown), which are stacked in this order from the first electrode 2. Furthermore, for example, the hole transport region 3 may have a structure of a hole injection layer 31 / a hole transport layer 32 / an electron blocking layer 33, which are stacked in this order from the first electrode 2. However, the structure of the hole transport region is not limited to this.

[0297] The hole injection layer 31 and other layers constituting the hole transport region 3 are not particularly limited, and may contain, for example, a known hole injection material. Examples of hole injection materials include phthalocyanine compounds such as copper phthalocyanine, DNTPD (N,N'-diphenyl-N,N'-bis-[4-(phenyl-m-tolyl-amino)-phenyl]-biphenyl-4,4'-diamine), m-MTDATA (4,4',4"-tris(3-methylphenylphenylamino)triphenylamine), TDATA (4,4',4"-tris(N,N-diphenylamino)triphenylamine), 2-TNATA (4,4',4"-tris{N,-(2-naphthyl)-N-phenylamino}-triphenylamine), PEDOT / PSS (poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate)), and PANI / DBSA (polyaniline). / dodecylbenzenesulfonic acid), PANI / CSA (polyaniline / camphorsulfonic acid), PANI / PSS (polyaniline) / poly(4-styrenesulfonate), NPB (N,N'-di(naphthalen-1-yl)-N,N'-diphenyl-benzidine), triphenylamine-containing polyether ketone (TPAPEK), 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate, HAT-CN (dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile), F6-TCNNQ (1,3,4,5,7,8-hexafluorotetracyano-2,6-naphthoquinodimethane), etc.

[0298] The hole transport layer 32 and other layers constituting the hole transport region 3 are not particularly limited, but may contain, for example, a known hole transport material. Examples of hole transport materials include carbazole derivatives such as N-phenylcarbazole and polyvinylcarbazole, fluorene derivatives, triphenylamine derivatives such as TPD (N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1-biphenyl]-4,4'-diamine) and TCTA (4,4',4"-tris(N-carbazolyl)triphenylamine), NPB (N,N'-di(naphthalen-1-yl)-N,N'-diphenyl-benzidine), TAPC (4,4'-cyclohexylidenebis[N,N-bis(4-methylphenyl)benzenamine]), HMTPD (4,4'-bis[N,N'-(3-tolyl)amino]-3,3'-dimethylbiphenyl), mCP (1,3-bis(N-carbazolyl)benzene), and the following compounds HTM1, HTM2, and HT1.

[0299] [ka]

[0300] In addition to the hole injection material and hole transport material described above, the hole transport region 3 may further contain a charge generation material to improve conductivity. The charge generation material is uniformly or non-uniformly dispersed in the hole transport region 3 or in each layer constituting the hole transport region 3. The charge generation material is not particularly limited, and examples thereof include known charge generation materials. Examples of the charge generation material include p-dopants. Examples of p-dopants include quinone derivatives such as TCNQ (tetracyanoquinodimethane) and F4-TCNQ (2,3,5,6-tetrafluorotetracyanoquinodimethane), metal oxides such as tungsten oxide and molybdenum oxide, and cyano group-containing compounds.

[0301] The hole buffer layer (not shown) compensates for the resonance distance depending on the wavelength of light emitted from the light-emitting layer 4, thereby increasing light emission efficiency. The material contained in the hole buffer layer (not shown) is not particularly limited, and materials used in hole buffer layers (not shown) can be used. For example, the compounds that can be contained in the hole transport region 3 as described above can be used.

[0302] The electron blocking layer 33 is a layer that serves to prevent electrons from being injected from the electron transport region 5 to the hole transport region 3. The material contained in the electron blocking layer 33 is not particularly limited, and any known material used for electron blocking layers 33 can be used. Examples include the host materials contained in the above-mentioned light-emitting layer (material for organic electroluminescence device), and preferred examples include the above-mentioned compounds H55, H86, and H87, which are host materials.

[0303] The thickness of the hole transport region 3 is not particularly limited, but is preferably 1 nm to 1000 nm, and more preferably 10 nm to 500 nm. Regarding the layers constituting the hole transport region 3, the thickness of the hole injection layer 31 is not particularly limited, but is preferably 3 nm to 200 nm. The thickness of the hole transport layer 32 is not particularly limited, but is preferably 3 nm to 200 nm. The thickness of the electron blocking layer 33 is not particularly limited, but is preferably 1 nm to 100 nm. The thickness of the hole buffer layer (not shown) is not particularly limited, as long as it functions as a hole buffer layer without interfering with the function of the organic electroluminescence device. When the thickness of the hole transport region 3, hole injection layer 31, hole transport layer 32, or electron blocking layer 33 satisfies the above range, better hole transport characteristics can be obtained while suppressing an increase in the actual driving voltage.

[0304] The method for forming the hole transport region 3 and each of the layers that constitute it is not particularly limited, but examples thereof include known film formation methods such as vacuum deposition, spin coating, LB method, inkjet printing, laser printing, and laser thermal transfer.

[0305] (Emitting layer 4) The light-emitting layer 4 is disposed on the hole transport region 3. Details of the light-emitting layer 4 are as described above.

[0306] (Electron transport area 5) The electron transport region 5 is disposed on the light-emitting layer 4. The electron transport region 5 includes at least one of an electron injection layer 51, an electron transport layer 52, and a hole blocking layer 53, although embodiments are not limited thereto.

[0307] The electron transport region 5 may be a single layer made of a single material, or a single layer made of multiple different materials. The electron transport region 5 may also have a multilayer structure having multiple layers made of multiple different materials. For example, the electron transport region 5 may have a single layer structure of an electron injection layer 51 or an electron transport layer 52. Alternatively, the electron transport region 5 may have a single layer structure made of an electron injection material and an electron transport material. Alternatively, the electron transport region 5 may have a structure of an electron transport layer 52 / electron injection layer 51, which are stacked in this order from the light-emitting layer 4. Alternatively, the electron transport region 5 may have a structure of a hole-blocking layer 53 / electron transport layer 52 / electron injection layer 51, which are stacked in this order from the light-emitting layer 4. However, the structure of the electron transport region 5 is not limited to these.

[0308] The electron injection layer 51 and other layers constituting the electron transport region 5 are not particularly limited and may contain, for example, a known electron injection material. Examples of electron injection materials include lanthanum group metals such as LiF, LiQ (lithium quinolate), LiO, BaO, NaCl, CsF, and Yb, and metal halides such as RbCl. The electron injection layer 51 is not particularly limited and may contain, for example, an electron transport material described below and an insulating organometallic salt. The organometallic salt is not particularly limited and may, for example, have an energy band gap of 4 eV or more. Examples of the organometallic salt include metal acetates, metal benzoates, metal acetoacetates, metal acetylacetonates, and metal stearates.

[0309] The electron transport layer 52 and other layers constituting the electron transport region 5 are not particularly limited, and may contain, for example, a known electron transport material. Examples of electron transport materials include anthracene compounds, Alq3 (tris(8-hydroxyquinolinolato)aluminum), 1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene, 2,4,6-tris(3'-pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine, 2-(4-(N-phenylbenzimidazolyl-1-ylphenyl)-9,10-dinaphthylanthracene), TPBi (1,3,5-tri(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl), BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), and Bphen (4,7-diphenyl-1,10-phenanthroline). -phenanthroline), TAZ (3-(4-biphenyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole), NTAZ (4-(naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole), tBu-PBD (2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole), BAlq (bis(2-methyl-8-quinolinolato-N1,O8)-(1,1'-biphenyl-4-olato)aluminum), Bebq2 (beryllium bis(benzoquinolin-10-olato), ADN (9,10-di(naphthalen-2-yl)anthracene), LiQ (Lithium quinolate), the following compounds ET1 and H91, etc. Also included are TRE314 (manufactured by Toray Industries, Inc., electron transport material), etc.

[0310] [ka]

[0311] The hole-blocking layer 53 serves to prevent holes from being injected from the hole-transporting region 3 to the electron-transporting region 5. The material contained in the hole-blocking layer 53 is not particularly limited, and any known material used for hole-blocking layers 53 can be used. The hole-blocking layer 53 may contain, for example, a known hole-blocking material. Examples of hole-blocking materials include BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) and BPhen (4,7-diphenyl-1,10-phenanthroline). Other examples include the host materials contained in the above-mentioned light-emitting layer (material for organic electroluminescence devices), and preferred examples include the above-mentioned compounds H77 and H87, which are host materials.

[0312] The thickness of the electron transport region 5 is not particularly limited, but is preferably 0.1 nm to 200 nm, and more preferably 30 nm to 150 nm. Regarding the layers constituting the electron transport region 5, the thickness of the electron transport layer 52 is not particularly limited, but is preferably 10 nm to 100 nm, and more preferably 15 nm to 50 nm. The thickness of the hole blocking layer 53 is not particularly limited, but is preferably 1 nm to 100 nm, and more preferably 5 nm to 30 nm. The thickness of the electron injection layer 51 is not particularly limited, but is preferably 0.1 nm to 10 nm, and more preferably 0.3 nm to 9 nm. When the thickness of the electron injection layer 51 is within the above range, better electron injection characteristics can be obtained while suppressing a substantial increase in driving voltage. When the thickness of the electron transport region 5, electron injection layer 51, electron transport layer 52, or hole blocking layer 53 is within the above range, better electron transport characteristics can be obtained while suppressing a substantial increase in driving voltage.

[0313] The method for forming the electron transport region 5 and each of the layers that constitute it is not particularly limited, but examples thereof include known film formation methods such as vacuum deposition, spin coating, LB method, inkjet printing, laser printing, and laser thermal transfer.

[0314] The second electrode 6 is disposed on the electron transport region 5. The second electrode 6 is conductive. In an organic electroluminescent device according to one embodiment of the present invention, the second electrode 6 is preferably a common electrode or a negative electrode. The second electrode 6 is preferably a transmissive electrode, a semi-transmissive electrode, or a reflective electrode.

[0315] The material constituting the second electrode 6 is not particularly limited, and examples thereof include metals, metal alloys, and conductive compounds. If the second electrode 6 is a transmissive electrode, the second electrode 6 preferably contains a transparent metal oxide such as ITO, IZO, ZnO, or ITZO. If the second electrode 6 is a semi-transmissive electrode or a reflective electrode, the second electrode 6 preferably contains Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, or a compound or mixture containing any of these (for example, a mixture of Ag and Mg).

[0316] The second electrode 6 may be a single layer made of a single material, a single layer made of multiple different materials, or a multi-layer structure having multiple layers made of multiple different materials.

[0317] The thickness of the second electrode 6 is not particularly limited, but is preferably 10 nm or more and 1000 nm or less.

[0318] The second electrode 6 may be connected to an auxiliary electrode (not shown). By connecting the second electrode 6 to the auxiliary electrode, the resistance of the second electrode 6 can be further reduced.

[0319] Furthermore, a capping layer (not shown) may be further disposed on the second electrode 6. The capping layer (not shown) is not particularly limited, and may be, for example, a layer containing α-NPD, NPB, TPD, m-MTDATA, Alq, CuPc, TPD15 (N,N,N',N'-tetra(biphenyl-4-yl)biphenyl-4,4'-diamine), TCTA (4,4',4"-tri-9-carbazolyltriphenylamine), N,N'-bis(naphthalen-1-yl), or the like.

[0320] The materials constituting the above-mentioned layers and electrodes may be used singly or in combination of two or more.

[0321] In the organic electroluminescence device 10 of FIGS. 1 to 3, the compound of the above formula (1) or the above material for an organic electroluminescence device may be contained in the light-emitting layer 4. Although it is preferable, the compound of formula (1) or the material for an organic electroluminescence device may be contained in the light-emitting layer 4 and an organic layer other than the light-emitting layer 4.

[0322] 1 to 3, when a voltage is applied to each of the first electrode 2 and the second electrode 6, holes injected from the first electrode 2 move to the light-emitting layer 4 via the hole transport region 3, and electrons injected from the second electrode 6 move to the light-emitting layer 4 via the electron transport region 5. The electrons and holes recombine in the light-emitting layer 4 to generate excitons, which emit light as they fall from the excited state to the ground state.

[0323] Although the embodiments of the present invention have been described in detail, it is clear that this is by way of illustration and example only and not of limitation, and that the scope of the present invention should be interpreted by the appended claims.

[0324] The present invention encompasses the following aspects and configurations.

[0325] [1] Formula (1):

[0326] [ka]

[0327] In formula (1), R 1 ~R 4 are each independently (1a) to (1d) below: (1a) a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms; (1b) a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms; (1c) a substituted or unsubstituted aromatic hydrocarbon group; or (1d) substituted or unsubstituted heterocyclic groups; and n1 to n4 are each independently 1, 2, 3, or 4, and when n1 is 2 or more, each R 1 may be the same or different, and when n2 is 2 or more, each R 2 may be the same or different, and when n3 is 2 or more, each R 3 may be the same or different, and when n4 is 2 or more, each R 4 may be the same or different: is a compound represented by the molecular weight of the compound is 1000 or more and 1400 or less, The molecular length L1 and molecular length L2 of the compound in the biaxial directions defined by the following formula are each independently 16 Å or more and 38 Å or less, The product of the molecular length L1 and the molecular length L2 is 490 Å 2 More than 1200Å 2 A compound which is:

[0328]

number

[0329] [2] The compound represented by the formula (1) is represented by the following formula (2):

[0330] [ka]

[0331] In equation (2), A a ~A d are each independently a benzene ring or a heterocycle, R a ~R d each independently represents a hydrogen atom, an unsubstituted alkyl group having from 1 to 20 carbon atoms, an unsubstituted alkoxy group having from 1 to 20 carbon atoms, an unsubstituted arylamino group having from 6 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted aromatic heterocyclic group; na is A a is a benzene ring, then 5, and A a When is a heterocycle, A a is the upper limit of the number of substitutions that can be made into nb is A b is a benzene ring, then 5, and A b When is a heterocycle, A b is the upper limit of the number of substitutions that can be made into nc is A c is a benzene ring, then 5, and A c When is a heterocycle, A c is the upper limit of the number of substitutions that can be made into nd is A d is a benzene ring, then 5, and A d When is a heterocycle, A d is the upper limit of the number of substitutions that can be made into X 1 ~X 4 are each independently a hydrogen atom, an unsubstituted alkyl group having from 1 to 20 carbon atoms, an unsubstituted alkoxy group having from 1 to 20 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group, m1 to m4 are 3: is a compound represented by the molecular weight of the compound is 1000 or more and 1400 or less, The molecular length L1 and molecular length L2 of the compound in the biaxial directions defined by the following formula are each independently 16 Å or more and 38 Å or less, The product of the molecular length L1 and the molecular length L2 is 490 Å 2 More than 1200Å 2 The compound according to [1] above, which is:

[0332]

number

[0333] [3] The compound represented by formula (1) is represented by the following formula (3):

[0334] [ka]

[0335] In equation (3), R 5 ~R 8 are each independently a hydrogen atom, an unsubstituted alkyl group having from 1 to 20 carbon atoms, an unsubstituted alkoxy group having from 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted aromatic heterocyclic group, n5 to n8 are 5, Y 1 ~Y 4 are each independently a hydrogen atom, an unsubstituted alkyl group having from 1 to 20 carbon atoms, an unsubstituted alkoxy group having from 1 to 20 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group, ng~nj is 3; is a compound represented by the molecular weight of the compound is 1000 or more and 1400 or less, The molecular length L1 and molecular length L2 of the compound in the biaxial directions defined by the following formula are each independently 16 Å or more and 38 Å or less, The product of the molecular length L1 and the molecular length L2 is 490 Å2 More than 1200Å 2 The compound according to the above [1] or [2], which is:

[0336]

number

[0337] [4] An organic electroluminescence device having a light-emitting layer containing the compound according to any one of [1] to [3] above.

[0338] [5] The organic electroluminescence device according to [4] above, wherein the light-emitting layer further contains a phosphorescent complex.

[0339] [6] The organic electroluminescence device according to the above [5], wherein the phosphorescent complex is a platinum complex.

[0340] [7] The organic electroluminescence device according to any one of the above [4] to [6], wherein the light-emitting layer further contains a host material.

[0341] [8] The organic electroluminescence device according to the above [7], wherein the host material includes a compound having a triphenylsilyl group.

[0342] [9] The organic electroluminescence device according to the above [7], wherein the host material contains a compound having an anthracene ring structure. [Example]

[0343] The present invention will be described in more detail using the following examples and comparative examples, but the technical scope of the present invention is not limited to the following examples.

[0344] <Compound design> For the following compounds, the compound structures were derived from simulation results using DFT calculations, and the molecular lengths L1 and L2 of the compounds were calculated based on the structures. Furthermore, using the relationship of the present invention, the transition dipole moment (TDO) of each compound was calculated based on the value obtained by multiplying the molecular lengths L1 and L2 of the compounds. The relationship of the present invention was calculated using a graph (see FIG. 4) showing the correlation between pre-calculated molecular length and TDO. The TDO corresponding to the value (x-axis) obtained by multiplying the calculated molecular lengths L1 and L2 was read from the graph curve. The TDO obtained using the relationship of the present invention is referred to as the predicted TDO. The value obtained by multiplying the molecular lengths L1 and L2 of the compounds and the predicted TDO results are shown in Table 1 (Tables 1-1 to 1-7 are collectively referred to as Table 1). Among the compounds in Table 1 below, compounds A1 to A38 are compounds represented by formula (1), and comparative compounds C1 to C3 are not compounds represented by formula (1). The measured TDO values ​​for comparative compounds C1 to C3 are also shown. Furthermore, for Compound 1 used in the following Examples, the predicted TDO calculated based on the value obtained by multiplying the molecular lengths L1 and L2, and the actually measured TDO are also shown in Table 1 (Table 1-7).

[0345] Here, the calculations by density functional theory (DFT) were performed using Gaussian 16 (Gaussian Inc.) as calculation software, according to the following calculation method (I): (I) S0 calculation method: Functional B3LYP, basis set 6-31G(d,p), geometry optimization calculation using DFT.

[0346] [Table 1-1]

[0347] [Table 1-2]

[0348] [Table 1-3]

[0349] [Table 1-4]

[0350] [Table 1-5]

[0351] [Table 1-6]

[0352] [Table 1-7]

[0353] <Synthesis of Compounds> Compound 1 was synthesized according to the following synthesis example for use in the production of an organic electroluminescence device. Compound 1 is a compound represented by formula (1). Comparative compound C1 was also prepared for use in the production of a comparative organic electroluminescence device.

[0354] [ka]

[0355] [Synthesis Example 1] Compound 1 was synthesized according to the following scheme.

[0356] [ka]

[0357] (Synthesis of Intermediate 1) Under a nitrogen atmosphere, a 100 mL three-neck flask was charged with 5-bromo-7-(tert-butyl)-1H-indole (1.0 g, 4.0 mmol), 4-tert-butylphenylboronic acid (1.3 g, 7.1 mmol), tetrakis(triphenylphosphine)palladium(0) (0.2 g, 0.2 mmol), potassium carbonate (1.1 g, 7.9 mmol), 20 mL of toluene, 10 mL of ethanol, and 10 mL of water. The resulting reaction mixture was heated to reflux for 2 hours. After cooling to room temperature, the ethanol was removed by distillation under reduced pressure, and toluene and water were added for washing and extraction. The resulting organic layer was dried over magnesium sulfate, filtered, and the solvent was removed by distillation under reduced pressure. The resulting solid was washed with methanol to obtain Intermediate 1 as a white powder. The yield of Intermediate 1 was 0.5 g (45%).

[0358] (Synthesis of Intermediate 2) Under a nitrogen atmosphere, 3',5'-di-tert-butyl-3-chloro-[1,1'-biphenyl]-4-carbaldehyde (6.8 g, 20.6 mmol), Intermediate 1 (6.3 g, 20.6 mmol), and 100 mL of acetonitrile were placed in a 100 mL three-neck flask. The resulting reaction solution was heated to 80 °C, and then 57% by mass hydroiodic acid (0.58 mL, 4.1 mmol) was added and stirred for 2 hours. The reaction solution was allowed to cool to room temperature, and the precipitated solid was filtered off and washed with chilled acetonitrile to obtain Intermediate 2 as a white powder. The yield of Intermediate 2 was 8.0 g (63%).

[0359] (Synthesis of Compound 1) Under a nitrogen atmosphere, a 100 mL three-neck flask was charged with intermediate 2 (3.0 g, 2.4 mmol), potassium carbonate (3.4 g, 24.3 mmol), copper(I) iodide (4.6 g, 24.3 mmol), 1,10-phenanthroline (4.4 g, 24.3 mmol), and 121 mL of 1,3-dimethyl-2-imidazolidinone. The resulting reaction solution was heated to 240°C with stirring for 2 hours. The reaction solution was then allowed to cool to room temperature, and the precipitated solid was filtered off. The filtered solid, 200 mL of methanol, and 50 mL of ethylenediamine were added to a 500 mL Erlenmeyer flask, and the mixture was stirred. The solid was then filtered off. The resulting solid was recrystallized using THF-acetonitrile to obtain compound 1 as a yellow solid. Compound 1 yield: 1.7 g (60%). LC-MS: 1158 ([M+H] + ).

[0360] [Compound data (identification data) for Compound 1] The structure of the obtained compound 1 was identified by nuclear magnetic resonance (H-NMR): NMR data (300MHz, CD2Cl2) (ppm) 1.49(9H,s),1.57(18H,s),2.09(9H,s),7.59(1H,s),7.70(2H,d,J=8.4Hz),7.80(2H,s),7.94-7.97(3H,m),8.04(1H,s),8.89-8.97(3H,m).

[0361] <Emission spectrum of solution> [Measurement method] The concentration of compound 1 is 1 x 10 -7 M (=mol / dm 3 The photoluminescence (PL) spectrum of a toluene solution of 1,2,3-trimethylsilyl benzoate (1,2,3,4-trimethylsilyl benzoate) was measured at room temperature using a Hitachi High-Technologies F-7000 spectrofluorometer with an excitation wavelength of 320 nm.

[0362] The emission spectrum of the toluene solution of Compound 1 measured by the above method is shown in Figure 5. Compound 1 of the present invention emitted blue light at an emission wavelength of 458 nm.

[0363] <Physical Properties of Thin Films> [Method for Producing Thin Film] On a quartz substrate, with respect to the total mass (100% by mass) of the compound represented by formula (1) and the host material, 1.5% by mass of the compound represented by formula (1) or the compound to be measured and 98.5% by mass of the host were used, and co-evaporation was carried out at a vacuum degree of 10 -5 Pa to produce a 50-nm-thick thin film. The host material used was compound H-H1 and compound H-E1 at a mass ratio; compound H-H1: compound H-E1 = 60:40. The structures of compound H-H1 and compound H-E1 are as follows.

[0364] [Chemical Formula]

[0365] [Measurement of Angular Resolved Photoluminescence (PL)] Using the CoCoLink Corp.'s Luxol OLED Analyzer, the above-prepared thin film was subjected to angular resolved PL measurement at room temperature with the excitation light set at 365 nm. The obtained evaluation results are shown in Table 2 below.

[0366] [Table 2]

[0367] In the host-dispersed state, the TDO of Compound 1 was 93%. Compound 1 has a newly introduced structure compared to Comparative Compound C1 having a tert-butylphenyl group and a di-tert-butylphenyl group as the main skeleton. As a result of the extension of the molecular length, the TDO has increased. On the other hand, in Comparative Compound C1, the TDO is as small as 63%. From this result, it can be seen that in Comparative Compound C1, the molecules are randomly oriented in the plane, while in Compound 1, the molecules are parallelly oriented in the in-plane direction. Since Compound 1 can obtain a higher light extraction efficiency, it can be seen that the compound of the present invention is excellent as a light-emitting dopant.

[0368] <Evaluation of OLED Device> [Fabrication of organic EL devices] (Preparing materials for forming each layer) As materials used to form each layer of the organic EL device, in addition to the compound 1 and comparative compound C1 obtained above, the following materials were prepared.

[0369] [ka]

[0370] <<Fabrication of organic EL elements 1>> Example 1 The electrode-patterned ITO glass substrate was cut into 50mm x 50mm x 0.7mm pieces, which were then ultrasonically cleaned in acetone, isopropyl alcohol, and pure water, in that order, for 15 minutes each, followed by UV ozone cleaning for 30 minutes.The following layers were deposited on the ITO electrode (anode) on this glass substrate using a vacuum deposition system.

[0371] First, F6-TCNNQ was vapor-deposited on the ITO electrode to form a hole injection layer with a thickness of 10 nm. Next, compound HT1 was vapor-deposited on the hole injection layer to form a hole transport layer with a thickness of 140 nm. Next, compound H-H1 was vapor-deposited on the hole transport layer to form an electron blocking layer with a thickness of 5 nm. In this way, a hole transport region was formed.

[0372] Compound H-H1, compound H-E1, and compound 1 obtained above were co-deposited on the hole transport region to form an emitting layer with a thickness of 40 nm. The emitting layer was formed so that the mass ratio of compound H-H1 and compound H-E1 in the emitting layer was compound H-H1:compound H-E1=60:40. The emitting layer was also formed so that the concentration of compound 1 in the emitting layer was 1.5 mass% relative to the total mass of compound H-H1, compound H-E1, and compound 1 (i.e., the total mass of the emitting layer). Compound H-H1 and compound H-E1 are host materials.

[0373] Compound H-E1 was vacuum-deposited on the light-emitting layer to form a hole-blocking layer with a thickness of 5 nm. Compound ET1 and LiQ were then co-deposited on the hole-blocking layer in a mass ratio of compound ET1:LiQ = 5:5 (unit: parts by mass) to form an electron-transporting layer with a thickness of 30 nm. LiQ was then vapor-deposited on the electron-transporting layer to form an electron-injecting layer with a thickness of 1 nm. Thus, an electron-transporting region was formed.

[0374] An organic EL device was fabricated by depositing Al (cathode) having a thickness of 100 nm on the electron injection layer.

[0375] Thereafter, in a nitrogen atmosphere glove box with a moisture concentration of 1 ppm or less and an oxygen concentration of 1 ppm or less, the organic EL element fabricated in the above process was sealed using a glass sealing can with a desiccant and an ultraviolet curing resin (MORESCO, product name WB90US), thus completing the organic EL element (1).

[0376] (Comparative Example 1) An organic EL element (2) was produced in the same manner as in Example 1 above, except that in the formation of the light-emitting layer, the compound 1 in the light-emitting layer was changed to comparative compound C1, and the organic EL element was then sealed to complete the organic EL element.

[0377] <<Fabrication of Organic EL Devices 2>> Example 2 An organic EL element (3) was produced and sealed in the same manner as in Example 1, except that the method for forming the light-emitting layer was changed to the following method.

[0378] The emitting layer was formed by co-depositing Compound H-H1, Compound H-E1, phosphorescent complex P1, and Compound 1 obtained above on a hole transport region obtained in the same manner as in Example 1 above, to form an emitting layer with a thickness of 40 nm. The emitting layer was formed so that the mass ratio of Compound H-H1, Compound H-E1, and phosphorescent complex P1 in the emitting layer was Compound H-H1:Compound H-E1:Phosphorescent complex P1=60:40:13. The emitting layer was formed so that the concentration of Compound 1 in the emitting layer was 0.4 mass% relative to the total mass of Compound H-H1, Compound H-E1, phosphorescent complex P1, and Compound 1 (i.e., the total mass of the emitting layer). Compounds H-H1 and H-E1 are host materials.

[0379] [ka]

[0380] (Comparative Example 2) An organic EL element (4) was produced in the same manner as in Example 2, except that in the film formation of the light-emitting layer, the compound 1 in the light-emitting layer was changed to the comparative compound C1, and the organic EL element was completed by sealing.

[0381] <Evaluation of organic EL elements> [External quantum efficiency] According to the following method, brightness is 1,000 cd / m 2 The results of evaluating the external quantum efficiency are shown in Table 3 below.

[0382] Using a DC constant voltage power supply (KEITHLEY, source meter 2400 type), the organic EL element was made to emit light while changing the applied voltage, and the luminance, emission spectrum, and amount of light emitted were measured using a luminance measuring device (Topcon, SR-3).

[0383] The external quantum efficiency was calculated from the emission spectrum, luminance, and current value at the time of measurement. 2 The external quantum efficiency at a current density of 0.1 mA / cm is defined as EQE [%].2 The external quantum efficiency at this temperature was defined as MaxEQE [%].

[0384] Next, the evaluation results of the OLED devices are shown in Table 3. The OLED device fabricated using Compound 1 of the present invention as the emitting material has a higher external quantum yield than the OLED device fabricated using Comparative Compound 1 as the emitting material. This clearly indicates that the high TDO of the present invention contributes to the improvement of light extraction efficiency, thereby contributing to the high efficiency of the device, and demonstrates that the compound of the present invention is excellent as an emitting dopant.

[0385] [Table 3]

[0386] As can be seen from Table 3, the OLED device fabricated using Compound 1 of the present invention as the emitting material has a higher external quantum yield than the OLED device fabricated using Comparative Compound C1 as the emitting material. This clearly shows that the high TDO of the present invention contributes to the improvement of light extraction efficiency, thereby contributing to the high efficiency of the device, and that the compound of the present invention is excellent as an emitting dopant.

[0387] The present invention has been described above with reference to embodiments and examples, but the present invention is not limited to the specific embodiments and examples, and various modifications and changes are possible within the scope of the invention described in the claims. [Explanation of symbols]

[0388] 1 board 2 1st electrode 3. Hole transport region 31 Hole injection layer 32 Hole transport layer 33 Electron blocking layer 4. Light-emitting layer 5 Electron transport area 51 Electron injection layer 52 Electron transport layer 53 Hole blocking layer 6 Second electrode 10 Organic electroluminescent device.

Claims

1. The following formula (1): 【number】 In formula (1), R １ ~R ４ are each independently The following (1a) to (1d): (1a) a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms; (1b) a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms; (1c) a substituted or unsubstituted aromatic hydrocarbon group; or (1d) a substituted or unsubstituted heterocyclic group; and n1 to n4 are each independently 1, 2, 3, or 4, and when n1 is 2 or more, each R １ may be the same or different, and when n2 is 2 or more, each R ２ may be the same or different, and when n3 is 2 or more, each R ３ may be the same or different, and when n4 is 2 or more, each R ４ can be the same or different: is a compound represented by the molecular weight of the compound is 1,000 or more and 1,400 or less, The molecular length L of the compound in the biaxial direction is defined by the following formula: １ and molecular length L ２ are each independently 16 Å or more and 38 Å or less, The molecular length L １ and the molecular length L ２ The product is 490 Å ２ More than 1200Å ２ A compound which is: [Equation 1]

2. The compound represented by formula (1) is represented by the following formula (2): 【number】 In formula (2), A ａ ~A ｄ are each independently a benzene ring or a heterocycle, R ａ ~R ｄ each independently represents a hydrogen atom, an unsubstituted alkyl group having from 1 to 20 carbon atoms, an unsubstituted alkoxy group having from 1 to 20 carbon atoms, an unsubstituted arylamino group having from 6 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted aromatic heterocyclic group; na is A ａ is a benzene ring, it is 5, and A ａ When A is a heterocycle, ａ is the upper limit of the number of substitutions that can be made into nb is A ｂ is a benzene ring, it is 5, and A ｂ When A is a heterocycle, ｂ is the upper limit of the number of substitutions that can be made into nc is A ｃ is a benzene ring, it is 5, and A ｃ When A is a heterocycle, ｃ is the upper limit of the number of substitutions that can be made into nd is A ｄ is a benzene ring, it is 5, and A ｄ When A is a heterocycle, ｄ is the upper limit of the number of substitutions that can be made into X １ ~X ４ are each independently a hydrogen atom, an unsubstituted alkyl group having from 1 to 20 carbon atoms, an unsubstituted alkoxy group having from 1 to 20 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group, m1 to m4 are 3; is expressed as the molecular weight of the compound is 1,000 or more and 1,400 or less, The molecular length L of the compound in the biaxial direction is defined by the following formula: ３ and molecular length L ４ are each independently 16 Å or more and 38 Å or less, The molecular length L ３ and the molecular length L ４ The product is 490 Å ２ More than 1200Å ２ The compound of claim 1, which is: [Equation 2]

3. The compound represented by formula (1) is represented by the following formula (3): 【number】 In formula (3), R ５ ~R ８ each independently represents a hydrogen atom, an unsubstituted alkyl group having from 1 to 20 carbon atoms, an unsubstituted alkoxy group having from 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted aromatic heterocyclic group, n5 to n8 are 5, Y １ ~Y ４ are each independently a hydrogen atom, an unsubstituted alkyl group having from 1 to 20 carbon atoms, an unsubstituted alkoxy group having from 1 to 20 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group, ng to nj are 3; is expressed as the molecular weight of the compound is 1,000 or more and 1,400 or less, The molecular length L of the compound in the biaxial direction is defined by the following formula: ５ and molecular length L ６ are each independently 16 Å or more and 38 Å or less, The molecular length L ５ and the molecular length L ６ The product is 490 Å ２ More than 1200Å ２ The compound of claim 1, which is: [Equation 3]

4. An organic electroluminescence device having a light-emitting layer comprising the compound according to claim 1.

5. The organic electroluminescence device according to claim 4 , wherein the light-emitting layer further contains a phosphorescent complex.

6. The organic electroluminescence device according to claim 5 , wherein the phosphorescent complex is a platinum complex.

7. The organic electroluminescence device according to claim 4 , wherein the light-emitting layer further comprises a host material.

8. The organic electroluminescence device according to claim 7 , wherein the host material includes a compound having a triphenylsilyl group.

9. The organic electroluminescence device according to claim 7 , wherein the host material includes a compound having an anthracene ring structure.

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