Materials for light-emitting devices

Abstract

To provide a material for an electron transport layer with a low refractive index.SOLUTION: A material for a light-emitting device or a material for an electron transport layer includes an organic compound including a pyridine skeleton, a diazine skeleton, or a triazine skeleton, in which the ratio of carbon atoms coupled in an sp3 hybrid orbital constituting a saturated hydrocarbon group is in a certain range. The material for a light-emitting device or the material for an electron transport layer includes at least one 6-membered complex aromatic ring including 1 to 3 nitrogen atoms, a plurality of aromatic hydrocarbon rings in which the number of carbon atoms forming the ring is 6 to 14, in which at least two of the aromatic hydrocarbon rings are benzene rings, and an organic compound including a plurality of hydrocarbon groups forming a bond in the sp3 hybrid orbital. The ordinary ray refractive index of a layer including the organic compound to the light of any wavelength in the range of 455 nm or more and 465 nm or less is 1.5 or more and 1.75 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] One aspect of the present invention relates to organic compounds, light-emitting devices, display modules, lighting modules, display devices, light-emitting devices, electronic devices, lighting devices, and electronic devices. However, one aspect of the present invention is not limited to the above-mentioned technical field. One aspect of the present invention disclosed herein relates to a product, a method, or a method of manufacture. Alternatively, one aspect of the present invention relates to a process, a machine, a manufacture, or a composition of matter. More specifically, one example of a technical field of one aspect of the present invention disclosed herein is a semiconductor device, a display device, a liquid crystal display device, a light-emitting device, a lighting device, a power storage device, a memory device, an imaging device, a method of driving them, or a method of manufacturing them. [Background technology]

[0002] The practical application of light-emitting devices (organic EL devices) that utilize electroluminescence (EL) using organic compounds is progressing. The basic structure of these light-emitting devices is an organic compound layer (EL layer) containing a light-emitting material sandwiched between a pair of electrodes. By applying a voltage to this device, carriers are injected, and by utilizing the recombination energy of these carriers, light emission can be obtained from the light-emitting material.

[0003] Because these light-emitting devices are self-emissive, using them as pixels in a display offers advantages over liquid crystal displays, such as higher visibility and the elimination of the need for a backlight, making them suitable as flat-panel display elements. Furthermore, displays using such light-emitting devices can be manufactured to be thin and lightweight, which is a significant advantage. Another characteristic is their extremely fast response speed.

[0004] Furthermore, since these light-emitting devices can form a light-emitting layer continuously in two dimensions, they can produce light in a planar manner. This is a feature that is difficult to obtain with point light sources such as incandescent bulbs and LEDs, or line light sources such as fluorescent lamps, and therefore has high value as a planar light source that can be applied to lighting and other applications.

[0005] While displays and lighting devices using light-emitting devices are suitable for various electronic devices, research and development are underway to find light-emitting devices with even better characteristics.

[0006] One of the problems often raised when discussing organic EL devices is their low light extraction efficiency. In particular, attenuation due to reflection caused by differences in refractive index between adjacent layers is a major factor in reducing the efficiency of the device. To mitigate this effect, a configuration has been proposed in which a layer made of a low refractive index material is formed inside the EL layer (see, for example, Non-Patent Document 1).

[0007] Light-emitting devices with this configuration can achieve higher light extraction efficiency, and consequently higher external quantum efficiency, than light-emitting devices with conventional configurations. However, forming such a low refractive index layer within the EL layer without adversely affecting other important properties of the light-emitting device is not easy. This is because there is a trade-off between a low refractive index and high carrier transportability or reliability when used in a light-emitting device. This problem stems from the fact that carrier transportability and reliability in organic compounds largely depend on the presence of unsaturated bonds, and organic compounds with many unsaturated bonds tend to have high refractive indices. [Prior art documents] [Non-patent literature]

[0008] [Non-Patent Document 1] Jaeho Lee, et al., "Synergetic electrode architecture for efficient graphene-based flexible organic light-emitting diodes," Nature Communications, June 2, 2016, DOI: 10.1038 / ncomms11791 [Overview of the project] [Problems that the invention aims to solve]

[0009] One aspect of the present invention aims to provide a novel material for a light-emitting device or a novel material for an electron transport layer. Another aspect of the present invention aims to provide a novel material for a light-emitting device or an electron transport layer with a low refractive index. Alternatively, one aspect of the present invention aims to provide a novel material for a light-emitting device or an electron transport layer with a low refractive index and carrier transport properties. Alternatively, one aspect of the present invention aims to provide a novel material for a light-emitting device or an electron transport layer with a low refractive index and electron transport properties.

[0010] One aspect of the present invention aims to provide a novel organic compound. Alternatively, one aspect of the present invention aims to provide a novel organic compound having carrier transport properties. Alternatively, one aspect of the present invention aims to provide a novel organic compound having electron transport properties. One aspect of the present invention aims to provide an organic compound with a low refractive index. Alternatively, one aspect of the present invention aims to provide an organic compound with a low refractive index and carrier transport properties. Alternatively, one aspect of the present invention aims to provide an organic compound with a low refractive index and electron transport properties.

[0011] Alternatively, in another aspect of the present invention, the objective is to provide a light-emitting device with high luminous efficiency. Alternatively, in another aspect of the present invention, the objective is to provide a light-emitting device, light-emitting apparatus, electronic device, display device, and electronic device, respectively, with low power consumption.

[0012] Furthermore, the description of these problems does not preclude the existence of other problems. Moreover, one aspect of the present invention does not necessarily have to solve all of these problems. Other problems will naturally become clear from the description in the specification, drawings, and claims, and it is possible to extract other problems from the description in the specification, drawings, and claims.

[0013] The present invention only needs to solve one of the above-mentioned problems. [Means for solving the problem]

[0014] One aspect of the present invention is a material for light-emitting devices comprising an organic compound having a pyridine skeleton, a diazine skeleton, or a triazine skeleton, wherein the proportion of carbon atoms bonded in sp3 hybrid orbitals constituting a saturated hydrocarbon group is within a certain range. Since this material for light-emitting devices possesses both low refractive index optical properties and electron transport properties, it is suitable for electron transport layers in photoelectronic devices such as light-emitting devices and photoelectric conversion elements, and can therefore be used as an electron transport layer material.

[0015] One aspect of the present invention is a material for a light-emitting device or an electron transport layer material comprising an organic compound having at least one six-membered heteroaromatic ring containing one to three nitrogen atoms, wherein the glass transition temperature of the organic compound is 90°C or higher, and the refractive index of the layer made of the organic compound is 1.5 or higher and 1.75 or lower. Alternatively, one aspect of the present invention is a material for a light-emitting device or an electron transport layer material comprising an organic compound having at least one six-membered heteroaromatic ring containing one to three nitrogen atoms, wherein the glass transition temperature of the organic compound is 90°C or higher, and the ratio of the total number of carbon atoms forming bonds in sp3 hybrid orbitals to the total number of carbon atoms in the molecule of the organic compound is 10% or higher and 60% or lower. Alternatively, one aspect of the present invention is a material for a light-emitting device or an electron transport layer material comprising an organic compound having at least one six-membered heteroaromatic ring containing one to three nitrogen atoms, wherein the glass transition temperature of the organic compound is 90°C or higher, 1 The material is a light-emitting device material or an electron transport layer material in which the integral value of signals less than 4 ppm, as measured by 1H-NMR of the organic compound, is at least half the integral value of signals of 4 ppm or more.

[0016] In addition, the heteroaromatic ring in the above organic compound is preferably a triazine ring or a diazine ring, and more preferably a triazine ring or a pyrimidine ring. Furthermore, the glass transition temperature is preferably 100°C or higher, more preferably 110°C or higher, and even more preferably 120°C or higher.

[0017] One aspect of the present invention is a material for a light-emitting device or an electron transport layer, comprising an organic compound having at least one six-membered heteroaromatic ring containing one to three nitrogen atoms, a plurality of aromatic hydrocarbon rings having 6 to 14 carbon atoms forming the ring, at least two of the plurality of aromatic hydrocarbon rings being benzene rings, and a plurality of hydrocarbon groups having bonds formed by sp3 hybrid orbitals, wherein the ordinary refractive index of the layer made of the organic compound for light of any wavelength in the range of 455 nm to 465 nm is 1.5 to 1.75. It is preferable that the benzene rings be monocyclic benzene rings, i.e., benzene rings not fused with other aromatic hydrocarbon rings.

[0018] Another aspect of the present invention is a material for a light-emitting device or an electron transport layer, comprising an organic compound having at least one six-membered heteroaromatic ring containing one to three nitrogen atoms, a plurality of aromatic hydrocarbon rings having 6 to 14 carbon atoms forming the ring, at least two of the plurality of aromatic hydrocarbon rings being benzene rings, and a plurality of hydrocarbon groups having bonds formed by sp3 hybrid orbitals, wherein the ratio of the total number of carbon atoms forming bonds by sp3 hybrid orbitals to the total number of carbon atoms in the molecule of the organic compound is 10% or more and 60% or less.

[0019] In the above configuration, the ratio of the total number of carbon atoms forming bonds with sp3 hybrid orbitals to the total number of carbon atoms in the molecule of the organic compound is 10% or more and 50% or less, making it a material for light-emitting devices or an electron transport layer.

[0020] Another aspect of the present invention is a material for light-emitting devices or an electron transport layer, comprising an organic compound having at least one six-membered heteroaromatic ring containing one to three nitrogen atoms, a plurality of aromatic hydrocarbon rings having 6 to 14 carbon atoms forming the ring, at least two of the plurality of aromatic hydrocarbon rings being benzene rings, and a plurality of hydrocarbon groups having bonds formed by sp3 hybrid orbitals, wherein the integral value of signals less than 4 ppm in the measurement of the organic compound by 1H-NMR is at least half the integral value of signals of 4 ppm or more.

[0021] In each of the above configurations, the molecular weight of the organic compound contained in the material for the light-emitting device or the material for the electron transport layer is preferably 500 or more and 2000 or less.

[0022] In each of the above configurations, it is preferable that the hydrocarbon group within the molecule of the organic compound contained in the light-emitting device material or the electron transport layer material is bonded to an aromatic hydrocarbon ring, and that the lowest unoccupied molecular orbital (LUMO) is not distributed in the aromatic hydrocarbon ring to which the hydrocarbon group is bonded; that is, that the LUMO is distributed in a ring other than the aromatic hydrocarbon ring to which the hydrocarbon group is bonded within the molecule of the organic compound. However, in the above, "there is no LUMO distributed in the aromatic hydrocarbon ring to which the hydrocarbon group is bonded" means, in this specification, that the distribution density of LUMO in the aromatic hydrocarbon ring to which the hydrocarbon group is bonded is 0.06 [electrons / au 3 This means less than 0.02, more preferably less than 0.02.

[0023] In each of the above configurations, it is preferable that at least one of the aromatic hydrocarbon rings to which the hydrocarbon group is bonded within the molecule of the organic compound contained in the light-emitting device material or the electron transport layer material is a benzene ring.

[0024] In each of the above configurations, the organic compound contained in the material for the light-emitting device or the material for the electron transport layer preferably has at least three benzene rings, and all three benzene rings are preferably bonded to a six-membered heteroaromatic ring.

[0025] In each of the above configurations, the organic compound contained in the material for the light-emitting device or the material for the electron transport layer preferably has at least three benzene rings, all three benzene rings are bonded to a six-membered heteroaromatic ring, and two of the three benzene rings are substituted or unsubstituted phenyl groups and preferably do not have a hydrocarbon group.

[0026] In each of the above configurations, the organic compound contained in the material for the light-emitting device or the material for the electron transport layer is a material for the light-emitting device or an electron transport layer having a substituted or unsubstituted pyridyl group.

[0027] In the above configuration, the six-membered heteroaromatic ring is preferably a triazine ring.

[0028] Alternatively, in the above configuration, the six-membered heteroaromatic ring is preferably a pyrimidine ring.

[0029] In each of the above configurations, the hydrocarbon group forming a bond with an sp3 hybrid orbital is preferably an alkyl group or a cycloalkyl group.

[0030] In the above configuration, the alkyl group preferably has branching with 3 to 5 carbon atoms.

[0031] In the above-mentioned materials for light-emitting devices or electron transport layers, the glass transition temperature of the organic compound is preferably 90°C or higher. More preferably, the glass transition temperature is 100°C or higher, even more preferably 110°C or higher, and particularly preferably 120°C or higher.

[0032] Another aspect of the present invention is an organic compound represented by the general formula (G1).

[0033] [ka]

[0034] In the above general formula (G1), A represents a six-membered heteroaromatic ring containing one to three nitrogen atoms. Also, R 0 R represents hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or a substituent represented by formula (G1-1). 1 ~R 15At least one of them is a phenyl group having a substituent, and the others each independently represent any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 14 carbon atoms forming a substituted or unsubstituted ring, and a substituted or unsubstituted pyridyl group. The phenyl group having a substituent has one or two substituents, and each of the substituents independently represents any one of an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 14 carbon atoms forming a substituted or unsubstituted ring, and a heteroaromatic ring group having 3 to 9 carbon atoms forming a substituted or unsubstituted ring. The organic compound represented by the general formula (G1) has a plurality of hydrocarbon groups selected from an alkyl group having 1 to 6 carbon atoms and an alicyclic group having 3 to 10 carbon atoms, and the ratio of the total number of carbon atoms forming bonds with sp3 hybrid orbitals to the total number of carbon atoms in the molecule is 10% or more and 60% or less.

[0035] Another aspect of the present invention is an organic compound represented by the general formula (G2).

[0036]

Chemical formula

[0037] In the general formula (G2) above, A represents a 6-membered heteroaromatic ring containing 1 to 3 nitrogen atoms. Also, R 0 represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or a substituent represented by the formula (G2-1). Also, R 2 , R 4 , R 7 , R 9 , R 12 , R 14At least one of the atoms is a substituted phenyl group, and the others each independently represent one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 14 carbon atoms forming a substituted or unsubstituted ring, or a substituted or unsubstituted pyridyl group. The substituted phenyl group has one or two substituents, and each substituent is independently one of the following: an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 14 carbon atoms forming a substituted or unsubstituted ring, or a heteroaromatic ring group having 3 to 9 carbon atoms forming a substituted or unsubstituted ring. The organic compound represented by the above general formula (G2) has multiple hydrocarbon groups selected from alkyl groups having 1 to 6 carbon atoms and alicyclic groups having 3 to 10 carbon atoms, and the ratio of the total number of carbon atoms forming bonds in sp3 hybrid orbitals to the total number of carbon atoms in the molecule is 10% or more and 60% or less.

[0038] In each of the above configurations, it is preferable that A in general formula (G2) is one of the following: a pyridine ring, a pyrimidine ring, a pyrazine ring, a pyridazine ring, or a triazine ring.

[0039] Another aspect of the present invention is an organic compound represented by the general formula (G3).

[0040] [ka]

[0041] In the above general formula (G3), Q 1 ~Q 3 Of these, 2 or 3 represent N, and Q 1 ~Q 3 If 2 of them are N, the remaining 1 represents CH. Also R 1 ~R 15At least one of the atoms is a substituted phenyl group, and the others each independently represent one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 14 carbon atoms that forms a substituted or unsubstituted ring, or a substituted or unsubstituted pyridyl group. The substituted phenyl group has one or two substituents, and each substituent is independently one of the following: an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 14 carbon atoms that forms a substituted or unsubstituted ring, or a heteroaromatic ring group having 3 to 9 carbon atoms that forms a substituted or unsubstituted ring. The organic compound represented by the above general formula (G3) has multiple hydrocarbon groups selected from alkyl groups having 1 to 6 carbon atoms and alicyclic groups having 3 to 10 carbon atoms, and the ratio of the total number of carbon atoms forming bonds in sp3 hybrid orbitals to the total number of carbon atoms in the molecule is 10% or more and 60% or less.

[0042] Another aspect of the present invention is an organic compound represented by the general formula (G4).

[0043] [ka]

[0044] In the above general formula (G4), Q 1 ~Q 3 Of these, 2 or 3 represent N, and Q 1 ~Q 3 If 2 of them are N, the remaining 1 represents CH. Also, R 2 , R 4 , R 7 , R 9 , R 12 , R 14At least one of the atoms is a substituted phenyl group, and the others each independently represent one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 14 carbon atoms that forms a substituted or unsubstituted ring, or a substituted or unsubstituted pyridyl group. The substituted phenyl group has one or two substituents, and each substituent is each independently one of the following: an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 14 carbon atoms that forms a substituted or unsubstituted ring, or a heteroaromatic ring group having 3 to 9 carbon atoms that forms a substituted or unsubstituted ring. The organic compound represented by the above general formula (G4) has multiple hydrocarbon groups selected from alkyl groups having 1 to 6 carbon atoms and alicyclic groups having 3 to 10 carbon atoms, and the ratio of the total number of carbon atoms forming bonds in sp3 hybrid orbitals to the total number of carbon atoms in the molecule is 10% or more and 60% or less.

[0045] In each of the above configurations, the substituted phenyl group in the organic compounds represented by general formula (G1), general formula (G2), general formula (G3), and general formula (G4) is preferably represented by the following formula (G1-2).

[0046] [ka]

[0047] In the above general formula (G1-2), α represents a substituted or unsubstituted phenylene group. Also, R 20 α represents an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 14 carbon atoms that forms a substituted or unsubstituted ring. Also, m and n represent 1 to 2. Note that when m is 2, the multiple αs may be the same or different. Also, when n is 2, the multiple R 20 These can be the same or different.

[0048] In the above configuration, the group represented by the above general formula (G1-2) is R 2 and R 4It is preferable that either one or both of the above (however, the group represented by general formula (G1-2) is R 2 and R 4 If both conditions are met, the two bases represented by the above general formula (G1-2) may be the same or different.

[0049] In each of the above configurations, the substituted phenyl group in the organic compounds represented by general formula (G1), general formula (G2), general formula (G3), and general formula (G4) is preferably represented by the following general formula (G1-3).

[0050] [ka]

[0051] In the above general formula (G1-3), R 21 R represents one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or a substituent represented by the general formula (G1-3-1). 22 R represents a substituent represented by the general formula (G1-3-1). In the general formula (G1-3-1), 23 and R 24 R represents one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, or an alicyclic group having 3 to 10 carbon atoms. 23 and R 24 At least one of them is an alkyl group having 1 to 6 carbon atoms, or an alicyclic group having 3 to 10 carbon atoms. 23 and R 24 It is more preferable that both are alkyl groups having 1 to 6 carbon atoms, or alicyclic groups having 3 to 10 carbon atoms. Also, n represents 0 to 2. Note that if n is 2, multiple R 21 These can be the same or different. Note that if n is 0, R 23 and R 24 At least one of these is either an alkyl group having 1 to 6 carbon atoms, or an alicyclic group having 3 to 10 carbon atoms.

[0052] In the above configuration, the group represented by the above general formula (G1-3) is R in the organic compound represented by general formula (G1), general formula (G2), general formula (G3), and general formula (G4). 2 and R 4 It is preferable that either one or both of the above (however, the group represented by general formula (G1-3) is R 2 and R 4 If both conditions are met, the two groups represented by the above general formula (G1-3) may be the same or different.

[0053] In each of the above configurations, if the aromatic hydrocarbon group having 6 to 14 carbon atoms that forms a ring in the organic compound represented by general formula (G1), general formula (G2), general formula (G3), and general formula (G4) has substituents, it is preferable that the substituent is one of the following: an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an unsubstituted aromatic hydrocarbon group having 6 to 14 carbon atoms, or an aromatic hydrocarbon group having 6 to 14 carbon atoms that forms a ring and is substituted with an alkyl group having 1 to 6 carbon atoms or an alicyclic group having 3 to 10 carbon atoms.

[0054] In each of the above configurations, the aromatic hydrocarbon group having 6 to 14 carbon atoms forming the ring in the organic compound represented by general formula (G1), general formula (G2), general formula (G3), and general formula (G4), and the phenyl group having substituents represented by general formula (G1-2) and general formula (G1-3), is preferably one of a phenyl group, a naphthyl group, a phenantrenyl group, or a fluorenyl group.

[0055] In each of the above configurations, the organic compounds represented by general formula (G1), general formula (G2), general formula (G3), and general formula (G4), and the aromatic hydrocarbon groups having substituents represented by general formula (G1-2) and general formula (G1-3), with a ring-forming number of carbon atoms from 6 to 14, are preferably represented by any one of the following formulas (ra-1) to (ra-15).

[0056] [ka]

[0057] In each of the above configurations, the substituted or unsubstituted pyridyl groups in the organic compounds represented by general formula (G1), general formula (G2), general formula (G3), and general formula (G4) are preferably unsubstituted pyridyl groups or pyridyl groups substituted with one or more methyl groups.

[0058] In each of the above configurations, the alicyclic group in the organic compounds represented by general formula (G1), general formula (G2), general formula (G3), and general formula (G4) is preferably a cycloalkyl group having 3 to 6 carbon atoms.

[0059] In each of the above configurations, the alkyl group having 1 to 6 carbon atoms in the organic compound represented by general formula (G1), general formula (G2), general formula (G3), and general formula (G4) is preferably a branched alkyl group having 3 to 5 carbon atoms.

[0060] Another aspect of the present invention is an organic compound represented by the general formula (G4').

[0061] [ka]

[0062] In the above general formula (G4'), Q 1 ~Q 3 Of these, 2 or 3 represent N, and Q 1 ~Q 3 If two of them are N, the remaining one represents CH. Also, R 2 This is expressed by the following formula (R 2 (-1) is expressed as R 4 , R 7 , R 9 , R 12 , R 14 Each of these independently represents one of the following equations (r-1) to (r-20). Note that equation (R 2 -1) In this case, β represents a substituted or unsubstituted phenylene group, or a substituted or unsubstituted biphenyldiyl group, R25 represents one of the formulas (r-1) to (r-17), and n represents 1 or 2. The organic compound represented by the above general formula (G4') has multiple hydrocarbon groups selected from alkyl groups having 1 to 6 carbon atoms and alicyclic groups having 3 to 10 carbon atoms, and the ratio of the total number of carbon atoms forming bonds in sp3 hybrid orbitals to the total number of carbon atoms in the molecule is between 10% and 60%.

[0063] [ka]

[0064] Furthermore, (R in the organic compound represented by the above general formula (G4') 2 The above formula (R 2 -1) can be expressed as one of the following equations (r-1) to (r-20).

[0065] [ka]

[0066] As shown in formulas (r-1), (r-2), (r-5), and (r-6), it is preferable that the phenyl group is substituted with an alkyl or cycloalkyl group at the meta position, as this reduces the film density and lowers the refractive index. Furthermore, as shown in formulas (r-5) and (r-6), having two alkyl or cycloalkyl groups on the phenyl group is preferable because it easily increases the total number of carbon atoms forming bonds in sp3 hybrid orbitals, thus reducing synthesis costs. Also, as shown in formulas (r-3) and (r-4), it is preferable that the phenyl group is substituted with an alkyl or cycloalkyl group at the para position, as this allows for higher carrier mobility. When a pyridyl group is present, as shown in formulas (r-19) and (r-20), electron injection from the cathode or electron injection layer is easier, and the driving voltage can be reduced, which is preferable.

[0067] In the above configuration, the above formula (R 2 It is preferable that the β represented in (-1) is represented by any one of the following formulas (β-1) to (β-14).

[0068] [ka]

[0069] Another aspect of the present invention is an organic compound represented by any one of the following structural formulas (100), (120), (121), (200), (123), or (412).

[0070] [ka]

[0071] Another aspect of the present invention is a light-emitting device using the organic compound described above. Furthermore, the present invention also includes light-emitting devices having a guest material in addition to the organic compound.

[0072] Furthermore, the present invention also includes light-emitting devices formed using an organic compound, which is one embodiment of the present invention, in an EL layer between a pair of electrodes or in a light-emitting layer contained within the EL layer. In addition to the above light-emitting devices, cases in which a layer having an organic compound in contact with the electrodes (e.g., a cap layer) are also included as light-emitting devices and are included in the present invention. Furthermore, light-emitting devices having transistors, substrates, etc., in addition to light-emitting devices are also included in the scope of the invention. Moreover, electronic devices and lighting devices having these light-emitting devices and any of the following, such as sensors, operation buttons, speakers, or microphones, are also included in the scope of the invention.

[0073] Furthermore, one aspect of the present invention includes a light-emitting device having a light-emitting device, and further includes an illumination device having a light-emitting device. Accordingly, in this specification, a light-emitting device refers to an image display device or a light source (including an illumination device). In addition, modules to which connectors such as FPC (Flexible Printed Circuit) or TCP (Tape Carrier Package) are attached, modules to which a printed circuit board is provided at the end of the TCP, or modules to which an IC (Integrated Circuit) is directly mounted on the light-emitting device using the COG (Chip On Glass) method are all included as light-emitting devices. [Effects of the Invention]

[0074] In one aspect of the present invention, a novel material for a light-emitting device or a novel material for an electron transport layer can be provided. In one aspect of the present invention, a novel material for a light-emitting device or an electron transport layer with a low refractive index can be provided. Alternatively, in one aspect of the present invention, a novel material for a light-emitting device or an electron transport layer with a low refractive index and carrier transport properties can be provided. Alternatively, in one aspect of the present invention, a novel material for a light-emitting device or an electron transport layer with a low refractive index and electron transport properties can be provided.

[0075] In one aspect of the present invention, a novel organic compound can be provided. Alternatively, in one aspect of the present invention, a novel organic compound having carrier transport properties can be provided. Alternatively, in one aspect of the present invention, a novel organic compound having electron transport properties can be provided. In one aspect of the present invention, an organic compound with a low refractive index can be provided. Alternatively, in one aspect of the present invention, an organic compound with a low refractive index and carrier transport properties can be provided. Alternatively, in one aspect of the present invention, an organic compound with a low refractive index and electron transport properties can be provided.

[0076] Alternatively, in another aspect of the present invention, a light-emitting device with high luminous efficiency can be provided. Alternatively, in one aspect of the present invention, a light-emitting device, a light-emitting apparatus, an electronic device, a display device, and an electronic device with low power consumption can each be provided.

[0077] Furthermore, the description of these effects does not preclude the existence of other effects. Moreover, one aspect of the present invention does not necessarily have to possess all of these effects. Other effects will naturally become apparent from the description in the specification, drawings, and claims, and it is possible to extract other effects from the description in the specification, drawings, and claims. [Brief explanation of the drawing]

[0078] [Figure 1] Figures 1(A), 1(B), and 1(C) are schematic diagrams of the light-emitting device. [Figure 2] Figures 2(A) and 2(B) are conceptual diagrams of an active matrix type light-emitting device. [Figure 3] Figures 3(A) and 3(B) are conceptual diagrams of an active matrix type light-emitting device. [Figure 4] Figure 4 is a conceptual diagram of an active matrix type light-emitting device. [Figure 5] Figures 5(A) and 5(B) are conceptual diagrams of a passive matrix type light-emitting device. [Figure 6] Figures 6(A) and 6(B) are diagrams representing lighting devices. [Figure 7] Figures 7(A), 7(B1), 7(B2), and 7(C) are diagrams representing electronic devices. [Figure 8] Figures 8(A), 8(B), and 8(C) are diagrams representing electronic devices. [Figure 9] Figure 9 is a diagram representing a lighting device. [Figure 10] Figure 10 is a diagram representing a lighting device. [Figure 11] Figure 11 is a diagram representing an in-vehicle display device and lighting system. [Figure 12]Figures 12(A) and 12(B) are diagrams representing electronic devices. [Figure 13] Figures 13(A), 13(B), and 13(C) are diagrams representing electronic devices. [Figure 14] Figure 14 shows the MS spectrum of mmtBumBP-dmmtBuPTzn. [Figure 15] Figure 15 shows the measured refractive index data for mmtBumBP-dmmtBuPTzn. [Figure 16] Figure 16 shows the MS spectrum of mmtBumBPTzn. [Figure 17] Figure 17 shows the measured refractive index data for mmtBumPTzn. [Figure 18] Figure 18 shows the MS spectrum of mmtBumTPTzn. [Figure 19] Figure 19 shows the measured refractive index data for mmtBumTPTzn. [Figure 20] Figure 20 shows the MS spectrum of mmtBumBP-dmmtBuPPm. [Figure 21] Figure 21 shows the measured refractive index data for mmtBumBP-dmmtBuPPm. [Figure 22] Figure 22 shows the measured refractive index data for mmtBumBP-dmmtBuPTzn, mPn-mDMePyPTzn, Li-6mq, and Liq. [Figure 23] Figure 23 shows the luminance-current density characteristics of light-emitting device 1 and comparative light-emitting device 1. [Figure 24] Figure 24 shows the current efficiency-luminance characteristics of light-emitting device 1 and comparative light-emitting device 1. [Figure 25] Figure 25 shows the luminance-voltage characteristics of light-emitting device 1 and comparison light-emitting device 1. [Figure 26] Figure 26 shows the current-voltage characteristics of light-emitting device 1 and comparison light-emitting device 1. [Figure 27] Figure 27 shows the blue index-luminance characteristics of light-emitting device 1 and comparison light-emitting device 1. [Figure 28]Figure 28 shows the emission spectra of light-emitting device 1 and comparison light-emitting device 1. [Figure 29] Figure 29 shows the measured refractive index data for mmtBumBPTzn and mPn-mDMePyPTzn. [Figure 30] Figure 30 shows the luminance-current density characteristics of light-emitting device 2 and comparison light-emitting device 2. [Figure 31] Figure 31 shows the current efficiency-luminance characteristics of light-emitting device 2 and comparative light-emitting device 2. [Figure 32] Figure 32 shows the luminance-voltage characteristics of light-emitting device 2 and comparison light-emitting device 2. [Figure 33] Figure 33 shows the current-voltage characteristics of light-emitting device 2 and comparison light-emitting device 2. [Figure 34] Figure 34 shows the blue index-luminance characteristics of light-emitting device 2 and comparison light-emitting device 2. [Figure 35] Figure 35 shows the emission spectra of light-emitting device 2 and comparison light-emitting device 2. [Figure 36] Figure 36 shows the luminance-current density characteristics of light-emitting devices 3, 4, and 5. [Figure 37] Figure 37 shows the current efficiency-luminance characteristics of light-emitting devices 3, 4, and 5. [Figure 38] Figure 38 shows the luminance-voltage characteristics of light-emitting devices 3, 4, and 5. [Figure 39] Figure 39 shows the current density-voltage characteristics of light-emitting devices 3, 4, and 5. [Figure 40] Figure 40 shows the power efficiency-luminance characteristics of light-emitting devices 3, 4, and 5. [Figure 41] Figure 41 shows the emission spectra of light-emitting device 3, light-emitting device 4, and light-emitting device 5. [Figure 42] Figure 42 shows the external quantum efficiency-luminance characteristics of light-emitting devices 3, 4, and 5. [Figure 43]Figure 43 shows the reliability of light-emitting devices 3, 4, and 5. [Figure 44] Figure 44 shows the absorption and emission spectra of Li-6mq in an anhydrous acetone solution. [Figure 45] Figure 45 shows the luminance-current density characteristics of light-emitting device 6, light-emitting device 7, and comparative light-emitting device 3. [Figure 46] Figure 46 shows the current efficiency-luminance characteristics of light-emitting device 6, light-emitting device 7, and comparative light-emitting device 3. [Figure 47] Figure 47 shows the luminance-voltage characteristics of light-emitting device 6, light-emitting device 7, and comparison light-emitting device 3. [Figure 48] Figure 48 shows the current density-voltage characteristics of light-emitting device 6, light-emitting device 7, and comparison light-emitting device 3. [Figure 49] Figure 49 shows the external quantum efficiency-luminance characteristics of light-emitting device 6, light-emitting device 7, and comparative light-emitting device 3. [Figure 50] Figure 50 shows the emission spectra of light-emitting device 6, light-emitting device 7, and reference light-emitting device 3. [Figure 51] Figure 51 shows the normalized luminance-time variation characteristics of light-emitting device 6, light-emitting device 7, and comparative light-emitting device 3. [Figure 52] Figure 52 shows the MS spectrum of mmtBumTPTzn-02. [Figure 53] Figure 53 shows the measured refractive index data for mmtBumTPTzn-02. [Figure 54] Figure 54 shows the MS spectrum of mmtBumTPTzn-04. [Figure 55] Figure 55 shows the measured refractive index data for mmtBumTPTzn-04. [Figure 56] Figure 56 shows the MS spectrum of mmtBuPh-mDMePyPTzn. [Figure 57] Figure 57 shows the measured refractive index data for mmtBuPh-mDMePyPTzn. [Figure 58] Figure 58 shows the MS spectrum of mmchmBPTzn. [Figure 59] Figure 59 shows the measured refractive index data for mmchmBPTzn. [Figure 60] Figure 60 shows the MS spectrum of mmtBuTPTzn-03. [Figure 61] Figure 61 shows the measured refractive index data for mmtBuTPTzn-03. [Figure 62] Figure 62 shows the MS spectrum of mmtBumBP2Tzn. [Figure 63] Figure 63 shows the measured refractive index data for mmtBumBP2Tzn. [Figure 64] Figure 64 shows the MS spectrum of oBP-mmtBumBPTzn. [Figure 65] Figure 65 shows the measured refractive index data for oBP-mmtBumBPTzn. [Figure 66] Figure 66 shows the MS spectrum of oBP-mmtBuBPTzn. [Figure 67] Figure 67 shows the measured refractive index data for oBP-mmtBuBPTzn. [Figure 68] Figure 68 shows the MS spectrum of mmtBuPh-mPyPTzn. [Figure 69] Figure 69 shows the measured refractive index data for mmtBuPh-mPyPTzn. [Figure 70] Figure 70 shows the MS spectrum of mmtBuBP-mDMePyPTzn. [Figure 71] Figure 71 shows the measured refractive index data for mmtBuBP-mDMePyPTzn. [Figure 72] Figure 72 shows the luminance-current density characteristics of light-emitting device 8, light-emitting device 9, and comparative light-emitting device 4. [Figure 73] Figure 73 shows the luminance-voltage characteristics of light-emitting device 8, light-emitting device 9, and comparison light-emitting device 4. [Figure 74]Figure 74 shows the current efficiency-luminance characteristics of light-emitting device 8, light-emitting device 9, and comparative light-emitting device 4. [Figure 75] Figure 75 shows the current density-voltage characteristics of light-emitting device 8, light-emitting device 9, and comparative light-emitting device 4. [Figure 76] Figure 76 shows the external quantum efficiency-luminance characteristics of light-emitting device 8, light-emitting device 9, and comparative light-emitting device 4. [Figure 77] Figure 77 shows the emission spectra of light-emitting device 8, light-emitting device 9, and comparison light-emitting device 4. [Figure 78] Figure 78 shows the luminance-current density characteristics of light-emitting device 10 and comparative light-emitting device 5. [Figure 79] Figure 79 shows the luminance-voltage characteristics of light-emitting device 10 and comparison light-emitting device 5. [Figure 80] Figure 80 shows the current efficiency-luminance characteristics of light-emitting device 10 and comparative light-emitting device 5. [Figure 81] Figure 81 shows the current density-voltage characteristics of the light-emitting device 10 and the comparative light-emitting device 5. [Figure 82] Figure 82 shows the external quantum efficiency-luminance characteristics of light-emitting device 10 and comparative light-emitting device 5. [Figure 83] Figure 83 shows the emission spectra of light-emitting device 10 and comparison light-emitting device 5. [Figure 84] Figure 84 shows the MS spectrum of mmtBuBP-mDMePyPTzn-02. [Figure 85] Figure 85 shows the measured refractive index data for mmtBuBP-mDMePyPTzn-02. [Figure 86] Figure 86 shows the MS spectrum of oBP2-mmtBuPh-mDMePyPTzn. [Figure 87] Figure 87 shows the measured refractive index data for oBP2-mmtBuPh-mDMePyPTzn. [Figure 88]Figure 88 shows the MS spectrum of oBP-mmtBuPh-mDMePyPTzn. [Figure 89] Figure 89 shows the measured refractive index data for oBP-mmtBuPh-mDMePyPTzn. [Figure 90] Figure 90 shows the MS spectrum of tBu-TmPPPyTz. [Figure 91] Figure 91 shows the MS spectrum of tBu-TmPPPyTz-02. [Modes for carrying out the invention]

[0079] The embodiments of the present invention will be described in detail below with reference to the drawings. However, it will be readily apparent to those skilled in the art that the present invention is not limited to the following description, and that its form and details can be modified in various ways without departing from the spirit and scope of the present invention. Accordingly, the present invention shall not be interpreted as being limited to the contents of the embodiments shown below.

[0080] (Embodiment 1) Among organic compounds with carrier transport properties that can be used in organic EL devices, 1,1-bis-(4-bis(4-methylphenyl)-aminophenyl)-cyclohexane (abbreviated as TAPC) is known as one of the materials with a low refractive index. Since using a material with a low refractive index in the EL layer can increase the external quantum efficiency of the light-emitting device, it is expected that a light-emitting device with good external quantum efficiency can be obtained by using TAPC. However, TAPC has a low glass transition temperature, which gives it problems with heat resistance. Also, while TAPC can carry holes, it is practically unable to carry electrons.

[0081] Furthermore, in order to obtain a material with a low refractive index, it is preferable to introduce atoms with low atomic refraction into the molecule or to introduce substituents with low molecular refraction. Examples of substituents with low molecular refraction include saturated hydrocarbon groups and cyclic saturated hydrocarbon groups.

[0082] Generally, there is a trade-off relationship between carrier transport and refractive index, and it is commonly believed that increasing carrier transport leads to a higher refractive index. This is because carrier transport in organic compounds largely stems from the presence of unsaturated bonds, and organic compounds with many unsaturated bonds tend to have a high refractive index.

[0083] Furthermore, electron-transporting organic compounds are known to be more difficult to produce than hole-transporting organic compounds in terms of mobility, stability, and other properties necessary for use in organic EL devices, due to the low LUMO level required. For this reason, the introduction of saturated hydrocarbon groups, which negatively affect these properties, has been considered undesirable.

[0084] However, contrary to these conventional theories, the inventors have discovered a material for light-emitting devices containing an organic compound having a pyridine, diazine, or triazine skeleton in which the proportion of carbon atoms forming bonds in sp3 hybrid orbitals constituting a saturated hydrocarbon group is within a certain range, as a compound that combines carrier transport properties and a low refractive index. Furthermore, since this material for light-emitting devices possesses both low refractive index and electron transport properties, it is suitable for electron transport layers in photoelectronic devices such as light-emitting devices and photoelectric conversion devices, and can also be used as an electron transport layer material. In addition, by devising the number of substituents or substitution positions of substituents having carbon atoms forming bonds in sp3 hybrid orbitals among the substituents of the organic compound, it is possible to achieve a low refractive index while maintaining high electron transport properties. Moreover, by keeping the proportion of carbon atoms forming bonds in sp3 hybrid orbitals within a certain range in the organic compound, it is possible to obtain a material for light-emitting devices and an electron transport layer that possesses not only a low refractive index and high electron transport properties, but also heat resistance in the form of a high glass transition temperature.

[0085] Furthermore, by using a material for light-emitting devices, which is one aspect of the present invention, in the EL layer of a light-emitting device, the extraction efficiency of light in the EL layer can be improved by taking advantage of its low refractive index, thereby improving the luminous efficiency of the light-emitting device.

[0086] Furthermore, the electron transport layer material according to one aspect of the present invention is suitable for the electron transport layer of an EL layer in a light-emitting device because it has high electron transport properties, and by taking advantage of its low refractive index, it can also improve the efficiency of light extraction in the EL layer, thereby improving the luminous efficiency of the light-emitting device. In addition, the electron transport layer material according to one aspect of the present invention is suitable for the electron transport layer of a photoelectric conversion device because it has high electron transport properties and light (especially visible light) transmittance.

[0087] In other words, one aspect of the present invention is a material for light-emitting devices that can be used in the EL layer of a light-emitting device, or a material for an electron transport layer that can be used in an electron transport layer in the EL layer of a light-emitting device or an electron transport layer of a photoelectric conversion device. The material for light-emitting devices or an electron transport layer comprises an organic compound having at least one six-membered heteroaromatic ring containing one to three nitrogen atoms, the glass transition temperature of the organic compound is 90°C or higher, and the refractive index of the layer made of the organic compound is 1.5 or higher and 1.75 or lower. Alternatively, one aspect of the present invention is a material for light-emitting devices or an electron transport layer comprising an organic compound having at least one six-membered heteroaromatic ring containing one to three nitrogen atoms, the glass transition temperature of the organic compound is 90°C or higher, and the ratio of the total number of carbon atoms forming bonds in sp3 hybrid orbitals to the total number of carbon atoms in the molecule of the organic compound is 10% or higher and 60% or lower. Alternatively, one aspect of the present invention is a material for a light-emitting device or an electron transport layer comprising an organic compound having at least one six-membered heteroaromatic ring containing one to three nitrogen atoms, wherein the glass transition temperature of the organic compound is 90°C or higher. 1The material is a light-emitting device material or an electron transport layer material in which the integral value of signals less than 4 ppm, as measured by 1H-NMR of the organic compound, is at least half the integral value of signals of 4 ppm or more.

[0088] In addition, the heteroaromatic ring in the above organic compound is preferably a triazine ring or a diazine ring, and more preferably a triazine ring or a pyrimidine ring. Furthermore, the glass transition temperature is preferably 100°C or higher, more preferably 110°C or higher, and even more preferably 120°C or higher.

[0089] Furthermore, if anisotropy is present in the material, the refractive index for ordinary light (ordinary refractive index) and the refractive index for extraordinary light (extra-ordinary refractive index) may differ. If the thin film to be measured is in such a state, anisotropy analysis can be performed to separate the ordinary refractive index and the extra-ordinary refractive index and calculate each refractive index. In this specification, if both ordinary and extra-ordinary refractive indices are present in the measured material, the ordinary refractive index is used as the index.

[0090] Furthermore, one aspect of the present invention is a material for light-emitting devices that can be used in the EL layer of a light-emitting device, or a material for an electron transport layer that can be used in the electron transport layer of the EL layer of a light-emitting device or the electron transport layer of a photoelectric conversion device. The material for light-emitting devices or the material for an electron transport layer contains an organic compound having at least one six-membered heteroaromatic ring containing one to three nitrogen atoms, a plurality of aromatic hydrocarbon rings having 6 to 14 carbon atoms forming the ring, at least two of the plurality of aromatic hydrocarbon rings being benzene rings, and a plurality of hydrocarbon groups having bonds formed by sp3 hybrid orbitals, wherein the ordinary refractive index of the layer made of the organic compound for light of any wavelength in the range of 455 nm to 465 nm is 1.5 to 1.75.

[0091] Furthermore, the proportion of carbon atoms forming bonds in sp3 hybrid orbitals, as shown in the above configuration, affects the refractive index of the organic compound. In other words, as the total number of carbon atoms forming bonds in sp3 hybrid orbitals increases, the refractive index decreases, which can improve the light extraction efficiency of light-emitting devices using this compound.

[0092] Another aspect of the present invention is a material for light-emitting devices that can be used in the EL layer of a light-emitting device, or a material for an electron transport layer that can be used in the electron transport layer of the EL layer of a light-emitting device or the electron transport layer of a photoelectric conversion device, wherein the material contains an organic compound having at least one six-membered heteroaromatic ring containing one to three nitrogen atoms, and having a plurality of aromatic hydrocarbon rings having 6 to 14 carbon atoms forming the ring, at least two of the plurality of aromatic hydrocarbon rings being benzene rings, and having a plurality of hydrocarbon groups that form bonds with sp3 hybrid orbitals, and preferably the ratio of the total number of carbon atoms forming bonds with sp3 hybrid orbitals to the total number of carbon atoms in the molecule of the organic compound is 10% or more and 60% or less.

[0093] The proportion of carbon atoms forming bonds in sp3 hybrid orbitals, as shown in the above configuration, affects the refractive index of the organic compound. Specifically, an increase in the total number of carbon atoms forming bonds in sp3 hybrid orbitals lowers the refractive index, thus improving the light extraction efficiency of light-emitting devices using this compound. However, if the total number of carbon atoms forming bonds in sp3 hybrid orbitals becomes too high, the overlap of LUMO orbitals between adjacent molecules in the organic compound is inhibited, reducing carrier transport properties (such as electron transport and injection). Therefore, the proportion of carbon atoms forming bonds in sp3 hybrid orbitals relative to the total number of carbon atoms in the molecule is preferably 10% to 60%, and more preferably 20% to 50%. Furthermore, it is preferable that the proportion of carbon atoms forming bonds in sp3 hybrid orbitals relative to the total number of carbon atoms in the molecule be 20% to 40%.

[0094] Another aspect of the present invention is a material for light-emitting devices that can be used in the EL layer of a light-emitting device, or a material for an electron transport layer that can be used in the electron transport layer of the EL layer of a light-emitting device or the electron transport layer of a photoelectric conversion device, wherein the material contains an organic compound having at least one six-membered heteroaromatic ring containing one to three nitrogen atoms, and a plurality of aromatic hydrocarbon rings having six to fourteen carbon atoms forming the ring, at least two of the plurality of aromatic hydrocarbon rings being benzene rings, and a plurality of hydrocarbon groups having bonds formed by sp3 hybrid orbitals, and it is preferable that the integral value of signals less than 4 ppm in the measurement of the organic compound by 1H-NMR is at least half the integral value of signals of 4 ppm or more.

[0095] Furthermore, the proportion of total carbon atoms forming bonds in sp3 hybrid orbitals, as shown in the above configuration, affects the refractive index of the organic compound. That is, as the total number of carbon atoms forming bonds in sp3 hybrid orbitals increases, the refractive index decreases, which can improve the light extraction efficiency of light-emitting devices using this compound. In addition, a higher total number of carbon atoms forming bonds in sp3 hybrid orbitals improves heat resistance, such as the glass transition temperature, which is desirable. However, if the total number of carbon atoms forming bonds in sp3 hybrid orbitals becomes too high, the overlap of LUMO orbitals between adjacent molecules in the organic compound is inhibited, which reduces carrier transport properties (such as electron transport and injection). Therefore, in the results of 1H-NMR measurement of the organic compound, it is preferable that the integral value of signals less than 4 ppm originating from alkyl groups and alicyclic groups is 1 / 2 to 2 times, more preferably 1 to 1.5 times, the integral value of signals of 4 ppm or more originating from aryl groups or heteroaromatic groups.

[0096] Furthermore, the molecular weight of the organic compound contained in the above-mentioned material for light-emitting devices or electron transport layer is preferably 500 to 2000. More preferably, a molecular weight of 700 to 1500 is preferable because it also results in higher thermal properties (glass transition temperature) and makes the material less prone to decomposition during sublimation (deposition).

[0097] Furthermore, it is preferable that, within the molecule of the organic compound contained in the above-mentioned light-emitting device material or electron transport layer material, the hydrocarbon groups that form bonds with sp3 hybrid orbitals are all bonded to an aromatic hydrocarbon ring, and that LUMOs are not distributed in the aromatic hydrocarbon ring to which the hydrocarbon groups are bonded; that is, LUMOs are distributed in rings other than the aromatic hydrocarbon ring to which the hydrocarbon groups are bonded within the molecule of the organic compound. However, in the above, "LUMOs are not distributed in the aromatic hydrocarbon ring to which the hydrocarbon groups are bonded" means, in this specification, that the distribution density of LUMOs in the aromatic hydrocarbon ring to which the hydrocarbon groups are bonded is 0.06 [electrons / au 3 This means less than 0.02, more preferably less than 0.02.

[0098] Furthermore, it is more preferable that the LUMOs are mainly distributed in the heteroaromatic ring and the substituents directly bonded to it. By creating such a molecule, the LUMO orbitals of adjacent organic compound molecules in the solid (film) state are more likely to overlap, making it easier to transport electrons, and thus it is expected that the driving voltage can be reduced.

[0099] The isovalues ​​of LUMO can be determined using molecular orbital calculations such as Gaussian.

[0100] Furthermore, it is preferable that at least one of the aromatic hydrocarbon rings to which a hydrocarbon group forming a bond in an sp3 hybrid orbital is bonded within the molecule of the organic compound contained in the above-mentioned material for light-emitting devices or electron transport layer material is a benzene ring.

[0101] Furthermore, in the organic compound contained in the above-mentioned material for light-emitting devices or electron transport layer material, it is preferable that at least three benzene rings are present, all three benzene rings being bonded to a six-membered heteroaromatic ring, and that two of the three benzene rings are substituted or unsubstituted phenyl groups and do not contain hydrocarbon groups. In addition, a triazine ring or a pyrimidine ring is preferred as the six-membered heteroaromatic ring.

[0102] Furthermore, the organic compounds contained in the above-mentioned light-emitting device material or electron transport layer material preferably have substituted or unsubstituted pyridyl groups. Having substituted or unsubstituted pyridyl groups is preferable because it can enhance the electron injection from the cathode or electron injection layer.

[0103] Furthermore, the hydrocarbon groups in the organic compounds contained in the above-mentioned light-emitting device material or electron transport layer material that form bonds with sp3 hybrid orbitals are preferably alkyl groups or cycloalkyl groups, and the alkyl groups preferably have branching with 3 to 5 carbon atoms.

[0104] In the above-mentioned materials for light-emitting devices or electron transport layers, the glass transition temperature of the organic compound is preferably 90°C or higher. More preferably, the glass transition temperature is 100°C or higher, even more preferably 110°C or higher, and particularly preferably 120°C or higher.

[0105] Next, an organic compound that can also be applied as one embodiment of the organic compound contained in the above-mentioned light-emitting device material or electron transport layer material, and which is one embodiment of the present invention, will be described below.

[0106] In other words, one aspect of the present invention is an organic compound represented by general formula (G1).

[0107] [ka]

[0108] In general formula (G1), A represents a six-membered heteroaromatic ring containing one to three nitrogen atoms. Also, R 0 R represents hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or a substituent represented by formula (G1-1). 1 ~R 15At least one of the atoms is a substituted phenyl group, and the others each independently represent one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 14 carbon atoms forming a substituted or unsubstituted ring, or a substituted or unsubstituted pyridyl group. The substituted phenyl group has one or two substituents, and each substituent is independently one of the following: an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 14 carbon atoms forming a substituted or unsubstituted ring, or a heteroaromatic ring group having 3 to 9 carbon atoms forming a substituted or unsubstituted ring. The organic compound represented by the above general formula (G1) has multiple hydrocarbon groups selected from alkyl groups having 1 to 6 carbon atoms and alicyclic groups having 3 to 10 carbon atoms, and the ratio of the total number of carbon atoms forming bonds in sp3 hybrid orbitals to the total number of carbon atoms in the molecule is 10% to 60%.

[0109] In the composition of the organic compound represented by the general formula (G1) above, the proportion of the total number of carbon atoms forming bonds in sp3 hybrid orbitals affects the refractive index of the organic compound. That is, as the total number of carbon atoms forming bonds in sp3 hybrid orbitals increases, the refractive index decreases, which can improve the light extraction efficiency of light-emitting devices using this compound. Furthermore, a higher total number of carbon atoms forming bonds in sp3 hybrid orbitals improves heat resistance, such as the glass transition temperature, which is desirable. However, if the total number of carbon atoms forming bonds in sp3 hybrid orbitals becomes too high, the overlap of LUMO orbitals between adjacent molecules in the organic compound is inhibited, reducing carrier transport properties (such as electron transport and injection). Therefore, the proportion of the total number of carbon atoms forming bonds in sp3 hybrid orbitals to the total number of carbon atoms in the molecule is preferably 10% to 60%, and more preferably 20% to 50%. Moreover, it is preferable that the proportion of the total number of carbon atoms forming bonds in sp3 hybrid orbitals to the total number of carbon atoms in the molecule be 20% to 40%.

[0110] Furthermore, when the organic compound represented by the above general formula (G1) is formed only of a six-membered heteroaromatic ring containing one to three nitrogen atoms, a six-membered aromatic ring (i.e., a substituted or unsubstituted phenyl group), and a hydrocarbon group (alkyl group or alicyclic group) that forms a bond with sp3 hybrid orbitals (i.e., does not contain a fused ring), it is preferable because the refractive index becomes lower and the carrier (electron) transport properties become higher.

[0111] Furthermore, in the organic compound represented by the above general formula (G1), A can be a pyridine ring, a pyrimidine ring, a pyrazine ring, a pyridazine ring, or a triazine ring. When the organic compound represented by the above general formula (G1) is used in a layer in contact with the luminescent layer or the active layer, a triazine ring, pyrazine ring, or pyrimidine ring is preferred, and a triazine ring is particularly preferred, as these rings facilitate electron injection into these layers and have good electron transport properties.

[0112] Furthermore, in the organic compound represented by the above general formula (G1), the total number of substituents (alkyl groups and alicyclic groups) per molecule is more preferably 4 to 10, considering the synthesis cost, and even more preferably 6 or more to lower the refractive index. Similarly, using larger substituents (alkyl groups and alicyclic groups) is more effective in lowering the refractive index even with a smaller number of substituents, and considering the synthesis cost, it is more preferable that the number of carbon atoms in the alkyl group be 4 or more. It is even more preferable that the number of carbon atoms in the alicyclic group be 6 or more.

[0113] Furthermore, in the organic compound represented by the above general formula (G1), the aromatic hydrocarbon group having 6 to 14 carbon atoms that forms the ring can be a substituted or unsubstituted phenyl group, naphthyl group, phenanthryl group, or fluorenyl group. The phenyl group is particularly preferred because it can lower the refractive index. The naphthyl group, phenanthryl group, and fluorenyl group are also preferred because they can raise the glass transition temperature. Moreover, substituting these aromatic hydrocarbon groups having 6 to 14 carbon atoms that form the ring with a branched alkyl group or cycloalkyl group having 3 to 5 carbon atoms is preferred because it raises the glass transition temperature while simultaneously preventing an increase in refractive index (i.e., maintaining a low refractive index). Furthermore, from the viewpoint of reducing the refractive index, it is preferable that the aromatic hydrocarbon group having 6 to 14 carbon atoms that forms the ring is substituted with an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 14 carbon atoms that forms a ring substituted with an alkyl group having 1 to 6 carbon atoms or an alicyclic group having 3 to 10 carbon atoms. For example, phenyl groups substituted with alkyl groups having 1 to 6 carbon atoms or alicyclic groups having 3 to 10 carbon atoms are preferred, such as 1,3-di(t-butyl)phenyl group and 1,3-dicyclohexylphenyl group. Also preferred are phenyl groups substituted with alkyl groups having 1 to 6 carbon atoms or alicyclic groups having 3 to 10 carbon atoms, such as 3-t-butyl-5-[1,3-di(t-butyl)phenyl]phenyl group and 3-cyclohexyl-5-[1,3-dicyclohexylphenyl]phenyl group. Furthermore, when a fused ring is used and there are three or more fused rings, it is preferable that the other six-membered rings are fused only at the a, c, and e positions relative to the six-membered ring, as this allows for a lower refractive index compared to polyacene. For example, a phenanthrene ring can have a lower refractive index than an anthracene ring.

[0114] Furthermore, as the heteroaromatic ring group having 3 to 9 carbon atoms forming the ring in the organic compound represented by the general formula (G1) above, pyridyl group, pyrimidinyl group, pyrazinyl group, triazinyl group, quinolyl group, quinazolinyl group, quinoxalinyl group, and the like can be used.

[0115] Furthermore, in the organic compound represented by the above general formula (G1), the alkyl group having 1 to 6 carbon atoms can be a methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group, etc. In addition, the alicyclic group having 3 to 10 carbon atoms can be a cyclopropyl group, cyclohexyl group, cyclodecanyl group, bicyclooctyl group, adamantyl group, etc.

[0116] Another aspect of the present invention is an organic compound represented by the general formula (G2).

[0117] [ka]

[0118] In the general formula (G2), A represents a six-membered heteroaromatic ring containing one to three nitrogen atoms. 0 R represents one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or a substituent represented by formula (G2-1). 2 , R 4 , R 7 , R 9 , R 12 , R 14At least one of the atoms is a substituted phenyl group, and the others each independently represent one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 14 carbon atoms forming a substituted or unsubstituted ring, or a substituted or unsubstituted pyridyl group. The substituted phenyl group has one or two substituents, and each substituent is independently one of the following: an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 14 carbon atoms forming a substituted or unsubstituted ring, or a heteroaromatic ring group having 3 to 9 carbon atoms forming a substituted or unsubstituted ring. The organic compound represented by the above general formula (G2) has multiple hydrocarbon groups selected from alkyl groups having 1 to 6 carbon atoms and alicyclic groups having 3 to 10 carbon atoms, and the ratio of the total number of carbon atoms forming bonds in sp3 hybrid orbitals to the total number of carbon atoms in the molecule is 10% or more and 60% or less.

[0119] In the composition of the organic compound represented by the general formula (G2) above, the proportion of the total number of carbon atoms forming bonds in sp3 hybrid orbitals affects the refractive index of the organic compound. That is, as the total number of carbon atoms forming bonds in sp3 hybrid orbitals increases, the refractive index decreases, which can improve the light extraction efficiency of light-emitting devices using this compound. Furthermore, a higher total number of carbon atoms forming bonds in sp3 hybrid orbitals improves heat resistance, such as the glass transition temperature, which is desirable. However, if the total number of carbon atoms forming bonds in sp3 hybrid orbitals becomes too high, the overlap of LUMO orbitals between adjacent molecules in the organic compound is inhibited, reducing carrier transport properties (such as electron transport and injection). Therefore, the proportion of the total number of carbon atoms forming bonds in sp3 hybrid orbitals to the total number of carbon atoms in the molecule is preferably 10% to 60%, and more preferably 20% to 50%. Moreover, it is preferable that the proportion of the total number of carbon atoms forming bonds in sp3 hybrid orbitals to the total number of carbon atoms in the molecule be 20% to 40%.

[0120] Furthermore, when the organic compound represented by the above general formula (G2) is formed only of a six-membered heteroaromatic ring containing one to three nitrogen atoms, a six-membered aromatic ring (i.e., a substituted or unsubstituted phenyl group), and a hydrocarbon group (alkyl group or alicyclic group) that forms a bond with sp3 hybrid orbitals (i.e., does not contain a fused ring), it is preferable because the refractive index becomes lower and the carrier (electron) transport properties become higher.

[0121] Furthermore, in the organic compound represented by the above general formula (G2), A can be a pyridine ring, a pyrimidine ring, a pyrazine ring, a pyridazine ring, or a triazine ring. When the organic compound represented by the above general formula (G2) is used in a layer in contact with the luminescent layer or the active layer, a triazine ring, pyrazine ring, or pyrimidine ring is preferred, and a triazine ring is particularly preferred, as these rings readily inject electrons into these layers and have good electron transport properties.

[0122] Furthermore, in the organic compound represented by the above general formula (G2), the total number of substituents (alkyl groups and alicyclic groups) per molecule is more preferably 4 to 10, considering the synthesis cost, and even more preferably 6 or more to lower the refractive index. Similarly, using larger substituents (alkyl groups and alicyclic groups) is more effective in lowering the refractive index even with a smaller number of substituents, and considering the synthesis cost, it is more preferable that the number of carbon atoms in the alkyl group be 4 or more. It is even more preferable that the number of carbon atoms in the alicyclic group be 6 or more.

[0123] In the organic compound represented by the general formula (G2), as the aromatic hydrocarbon group having 6 to 14 carbon atoms forming a ring, a substituted or unsubstituted phenyl group, naphthyl group, phenanthryl group, or fluorenyl group can be used. In particular, a phenyl group is preferable because it can have a low refractive index. Further, a naphthyl group, phenanthryl group, or fluorenyl group is preferable because it can increase the glass transition point. Further, by substituting the aromatic hydrocarbon group having 6 to 14 carbon atoms forming these rings with a branched alkyl group or cycloalkyl group having 3 to 5 carbon atoms, an effect can be obtained in which the glass transition point increases and the refractive index does not increase (that is, a low refractive index is maintained), so it is preferable. Further, from the viewpoint of reducing the refractive index, the aromatic hydrocarbon group having 6 to 14 carbon atoms forming the above ring is preferably substituted with an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 14 carbon atoms forming a ring substituted with an alkyl group having 1 to 6 carbon atoms or an alicyclic group having 3 to 10 carbon atoms. For example, a phenyl group substituted with an alkyl group having 1 to 6 carbon atoms or an alicyclic group having 3 to 10 carbon atoms, such as a 1,3-di(t-butyl)phenyl group or a 1,3-dicyclohexylphenyl group, is preferable. Further, a phenyl group substituted with a phenyl group substituted with an alkyl group having 1 to 6 carbon atoms or an alicyclic group having 3 to 10 carbon atoms, such as a 3-t-butyl-5-[1,3-di(t-butyl)phenyl]phenyl group or a 3-cyclohexyl-5-[1,3-dicyclohexylphenyl]phenyl group, is preferable. Further, in the case of using a condensed ring, when the number of condensed rings is 3 or more, when another six-membered ring is condensed only at the a-position, c-position, and e-position with respect to the six-membered ring, the refractive index can be made lower than that of polyacene, so it is preferable. For example, the phenanthrene ring can have a lower refractive index than the anthracene ring.

[0124] In addition, as the heteroaromatic ring group having 3 to 9 carbon atoms forming a ring in the organic compound represented by the general formula (G2), a pyridyl group, a pyrimidinyl group, a pyrazinyl group, a triazinyl group, a quinolyl group, a quinazolinyl group, a quinoxalinyl group, etc. can be used.

[0125] In addition, as the alkyl group having 1 to 6 carbon atoms in the organic compound represented by the general formula (G2), a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group, etc. can be used. Further, as the alicyclic group having 3 to 10 carbon atoms, a cyclopropyl group, a cyclohexyl group, a cyclodecanyl group, a bicyclooctyl group, an adamantyl group, etc. can be used.

[0126] R 2 、R 4 、R 7 、R 9 、R 12 、R 14 As in the case of R

[0127] In addition, it is preferable that, among R 2 、R 4 、R 7 、R 9 、R 12 、R 14 at least two or more are hydrogen, because the steric hindrance around A can be reduced (the steric hindrance between A where the LUMO orbital is mainly distributed and its substituents can be reduced), the electron transporting property becomes good, and the driving voltage can be reduced.

[0128] Another aspect of the present invention is an organic compound represented by the general formula (G3).

[0129]

Chemical formula

[0130] In the general formula (G3), Q1 up to Q 3 Among them, 2 or 3 represent N, and Q 1 up to Q 3 When 2 of them are N, the remaining 1 represents CH. Also, R 1 up to R 15 At least one of them is a phenyl group having a substituent, and the others are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 14 carbon atoms forming a substituted or unsubstituted ring, or a substituted or unsubstituted pyridyl group. The phenyl group having a substituent has 1 or 2 substituents, and each of the substituents is independently an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 14 carbon atoms forming a substituted or unsubstituted ring, or a heteroaromatic ring group having 3 to 9 carbon atoms forming a substituted or unsubstituted ring. The organic compound represented by the above general formula (G3) has a plurality of hydrocarbon groups selected from an alkyl group having 1 to 6 carbon atoms and an alicyclic group having 3 to 10 carbon atoms, and the ratio of the total number of carbon atoms forming bonds with sp3 hybrid orbitals to the total number of carbon atoms in the molecule is 10% or more and 60% or less.

[0131] In the structure of the organic compound represented by the general formula (G3), the ratio of the total number of carbon atoms forming bonds with sp3 hybrid orbitals affects the refractive index of the organic compound. That is, as the total number of carbon atoms forming bonds with sp3 hybrid orbitals increases, the refractive index decreases, so the light extraction efficiency of a light-emitting device using this can be improved. Also, as the total number of carbon atoms forming bonds with sp3 hybrid orbitals increases, the heat resistance such as the glass transition point improves, which is preferable. However, if the total number of carbon atoms forming bonds with sp3 hybrid orbitals becomes too large, the overlap of the LUMO orbitals with adjacent molecules among the organic compound molecules is inhibited, resulting in a decrease in carrier transport properties (such as electron transport properties and injection properties). Therefore, the ratio of the total number of carbon atoms forming bonds with sp3 hybrid orbitals to the total number of carbon atoms in the molecule is preferably 10% or more and 60% or less, more preferably 20% or more and 50% or less. Further, it is preferable that the ratio of the total number of carbon atoms forming bonds with sp3 hybrid orbitals to the total number of carbon atoms in the molecule is 20% or more and 40% or less.

[0132] Also, when the organic compound represented by the general formula (G3) is composed of a 6-membered heteroaromatic ring containing Q 1 to Q 3 and a 6-membered aromatic ring (that is, a substituted or unsubstituted phenyl group) and only hydrocarbon groups (alkyl groups or alicyclic groups) forming bonds with sp3 hybrid orbitals (that is, when not including condensed rings), the refractive index is low and the carrier (electron) transport properties are also high, which is preferable.

[0133] Also, in the organic compound represented by the general formula (G3), as the 6-membered ring containing Q 1 to Q 3 a pyridine ring or a triazine ring can be used. When the organic compound represented by the general formula (G3) is used in a layer adjacent to the light-emitting layer or the active layer, a triazine ring, a pyrazine ring, or a pyrimidine ring, which are easy to inject electrons into these layers and have good electron transport properties, is preferable, and a triazine ring is particularly preferable.

[0134] Furthermore, in the organic compound represented by the above general formula (G3), the total number of substituents (alkyl groups and alicyclic groups) per molecule is more preferably 4 to 10, considering the synthesis cost, and even more preferably 6 or more to lower the refractive index. Similarly, using larger substituents (alkyl groups and alicyclic groups) is more effective in lowering the refractive index even with a smaller number of substituents, and considering the synthesis cost, it is more preferable that the number of carbon atoms in the alkyl group be 4 or more. It is even more preferable that the number of carbon atoms in the alicyclic group be 6 or more.

[0135] Furthermore, in the organic compound represented by the above general formula (G3), the aromatic hydrocarbon group having 6 to 14 carbon atoms that forms the ring can be a substituted or unsubstituted phenyl group, naphthyl group, phenanthryl group, or fluorenyl group. The phenyl group is particularly preferred because it can lower the refractive index. The naphthyl group, phenanthryl group, and fluorenyl group are also preferred because they can raise the glass transition temperature. Moreover, substituting these aromatic hydrocarbon groups having 6 to 14 carbon atoms that form the ring with a branched alkyl group or cycloalkyl group having 3 to 5 carbon atoms is preferred because it raises the glass transition temperature while simultaneously preventing an increase in refractive index (i.e., maintaining a low refractive index). Furthermore, from the viewpoint of reducing the refractive index, it is preferable that the aromatic hydrocarbon group having 6 to 14 carbon atoms that forms the ring is substituted with an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 14 carbon atoms that forms a ring substituted with an alkyl group having 1 to 6 carbon atoms or an alicyclic group having 3 to 10 carbon atoms. For example, phenyl groups substituted with alkyl groups having 1 to 6 carbon atoms or alicyclic groups having 3 to 10 carbon atoms are preferred, such as 1,3-di(t-butyl)phenyl group and 1,3-dicyclohexylphenyl group. Also preferred are phenyl groups substituted with alkyl groups having 1 to 6 carbon atoms or alicyclic groups having 3 to 10 carbon atoms, such as 3-t-butyl-5-[1,3-di(t-butyl)phenyl]phenyl group and 3-cyclohexyl-5-[1,3-dicyclohexylphenyl]phenyl group. Furthermore, when a fused ring is used and there are three or more fused rings, it is preferable that the other six-membered rings are fused only at the a, c, and e positions relative to the six-membered ring, as this allows for a lower refractive index compared to polyacene. For example, a phenanthrene ring can have a lower refractive index than an anthracene ring.

[0136] Furthermore, as the heteroaromatic ring group having 3 to 9 carbon atoms forming the ring in the organic compound represented by the general formula (G3) above, pyridyl group, pyrimidinyl group, pyrazinyl group, triazinyl group, quinolyl group, quinazolinyl group, quinoxalinyl group, and the like can be used.

[0137] Furthermore, in the organic compound represented by the above general formula (G3), the alkyl group having 1 to 6 carbon atoms can be a methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group, etc. In addition, the alicyclic group having 3 to 10 carbon atoms can be a cyclopropyl group, cyclohexyl group, cyclodecanyl group, bicyclooctyl group, adamantyl group, etc.

[0138] Another aspect of the present invention is an organic compound represented by the general formula (G4).

[0139] [ka]

[0140] In the above general formula (G4), Q 1 ~Q 3 Of these, 2 or 3 represent N, and Q 1 ~Q 3 If 2 of them are N, the remaining 1 represents CH. Also, R 2 , R 4 , R 7 , R 9 , R 12 , R 14At least one of the atoms is a substituted phenyl group, and the others each independently represent one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 14 carbon atoms that forms a substituted or unsubstituted ring, or a substituted or unsubstituted pyridyl group. The substituted phenyl group has one or two substituents, and each substituent is each independently one of the following: an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 14 carbon atoms that forms a substituted or unsubstituted ring, or a heteroaromatic ring group having 3 to 9 carbon atoms that forms a substituted or unsubstituted ring. The organic compound represented by the above general formula (G4) has multiple hydrocarbon groups selected from alkyl groups having 1 to 6 carbon atoms and alicyclic groups having 3 to 10 carbon atoms, and the ratio of the total number of carbon atoms forming bonds in sp3 hybrid orbitals to the total number of carbon atoms in the molecule is 10% or more and 60% or less.

[0141] In the composition of the organic compound represented by the general formula (G4) above, the proportion of the total number of carbon atoms forming bonds in sp3 hybrid orbitals affects the refractive index of the organic compound. That is, as the total number of carbon atoms forming bonds in sp3 hybrid orbitals increases, the refractive index decreases, which can improve the light extraction efficiency of light-emitting devices using this compound. Furthermore, a higher total number of carbon atoms forming bonds in sp3 hybrid orbitals improves heat resistance, such as the glass transition temperature, which is desirable. However, if the total number of carbon atoms forming bonds in sp3 hybrid orbitals becomes too high, the overlap of LUMO orbitals between adjacent molecules in the organic compound is inhibited, reducing carrier transport properties (such as electron transport and injection). Therefore, the proportion of the total number of carbon atoms forming bonds in sp3 hybrid orbitals to the total number of carbon atoms in the molecule is preferably 10% to 60%, and more preferably 20% to 50%. Moreover, it is preferable that the proportion of the total number of carbon atoms forming bonds in sp3 hybrid orbitals to the total number of carbon atoms in the molecule be 20% to 40%.

[0142] Furthermore, the organic compound represented by the above general formula (G4) is Q 1 ~Q 3When it is formed only by a 6-membered complex aromatic ring containing [a certain structure], a 6-membered aromatic ring (i.e., a substituted or unsubstituted phenyl group), and a hydrocarbon group (alkyl group or alicyclic group) that forms a bond with sp3 hybrid orbitals (i.e., does not contain a condensed ring), it is preferable because the refractive index is low and the carrier (electron) transportability is high.

[0143] Also, in the organic compound represented by the above general formula (G4), Q 1 to Q 3 As the 6-membered ring containing [a certain structure], a pyridine ring or a triazine ring can be used. When the organic compound represented by the above general formula (G4) is used in a layer adjacent to the light-emitting layer or the active layer, a triazine ring, a pyrazine ring, or a pyrimidine ring, which is easy to inject electrons into these layers and has good electron transportability, is preferable, and a triazine ring is particularly preferable.

[0144] Also, in the organic compound represented by the above general formula (G4), considering the synthesis cost, the total number of substituents (alkyl group and alicyclic group) per molecule is more preferably 4 or more and 10 or less, and even more preferably 6 or more to make the refractive index lower. Similarly, using relatively large substituents (alkyl group or alicyclic group) has the effect of effectively lowering the refractive index even when the number of substituents is small. Considering the synthesis cost, the number of carbon atoms of the alkyl group is more preferably 4 or more. The number of carbon atoms of the alicyclic group is more preferably 6 or more.

[0145] Furthermore, in the organic compound represented by the above general formula (G4), the aromatic hydrocarbon group having 6 to 14 carbon atoms that forms the ring can be a substituted or unsubstituted phenyl group, naphthyl group, phenanthryl group, or fluorenyl group. The phenyl group is particularly preferred because it can lower the refractive index. The naphthyl group, phenanthryl group, and fluorenyl group are also preferred because they can raise the glass transition temperature. Moreover, substituting these aromatic hydrocarbon groups having 6 to 14 carbon atoms that form the ring with a branched alkyl group or cycloalkyl group having 3 to 5 carbon atoms is preferred because it raises the glass transition temperature while simultaneously preventing an increase in refractive index (i.e., maintaining a low refractive index). Furthermore, from the viewpoint of reducing the refractive index, it is preferable that the aromatic hydrocarbon group having 6 to 14 carbon atoms that forms the ring is substituted with an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 14 carbon atoms that forms a ring substituted with an alkyl group having 1 to 6 carbon atoms or an alicyclic group having 3 to 10 carbon atoms. For example, phenyl groups substituted with alkyl groups having 1 to 6 carbon atoms or alicyclic groups having 3 to 10 carbon atoms are preferred, such as 1,3-di(t-butyl)phenyl group and 1,3-dicyclohexylphenyl group. Also preferred are phenyl groups substituted with alkyl groups having 1 to 6 carbon atoms or alicyclic groups having 3 to 10 carbon atoms, such as 3-t-butyl-5-[1,3-di(t-butyl)phenyl]phenyl group and 3-cyclohexyl-5-[1,3-dicyclohexylphenyl]phenyl group. Furthermore, when a fused ring is used and there are three or more fused rings, it is preferable that the other six-membered rings are fused only at the a, c, and e positions relative to the six-membered ring, as this allows for a lower refractive index compared to polyacene. For example, a phenanthrene ring can have a lower refractive index than an anthracene ring.

[0146] Furthermore, as heteroaromatic ring groups having 3 to 9 carbon atoms forming a ring in the organic compound represented by the general formula (G4) above, pyridyl groups, pyrimidinyl groups, pyrazinyl groups, triazinyl groups, quinolyl groups, quinazolinyl groups, quinoxalinyl groups, and the like can be used.

[0147] Furthermore, as alkyl groups having 1 to 6 carbon atoms in the organic compound represented by the above general formula (G4), methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, and hexyl groups can be used. In addition, as alicyclic groups having 3 to 10 carbon atoms, cyclopropyl, cyclohexyl, cyclodecanyl, bicyclooctyl, and adamantyl groups can be used.

[0148] In each of the above configurations, the substituted phenyl group in the organic compounds represented by general formula (G1), general formula (G2), general formula (G3), and general formula (G4) is preferably represented by the following general formula (G1-2).

[0149] [ka]

[0150] In the above general formula (G1-2), α represents a substituted or unsubstituted phenylene group. Also, R 20 α represents an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 14 carbon atoms forming a substituted or unsubstituted ring, or a heteroaromatic ring group having 3 to 9 carbon atoms forming a substituted or unsubstituted ring. Also, m and n represent 1 to 2. Note that when m is 2, the multiple αs may be the same or different. Also, when n is 2, the multiple Rs 20 These can be the same or different.

[0151] In the above configuration, the phenyl group having substituents represented by the above general formula (G1-2) is R in the organic compound represented by general formula (G1), general formula (G2), general formula (G3), and general formula (G4). 2 and R 4 It is preferable that either one or both of the above (however, the group represented by general formula (G1-2) is R 2 and R 4 If both conditions are met, the two bases represented by the above general formula (G1-2) may be the same or different.

[0152] Furthermore, as alkyl groups having 1 to 6 carbon atoms in the phenyl group having substituents represented by the general formula (G1-2) above, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, and hexyl groups can be used. In addition, as alicyclic groups having 3 to 10 carbon atoms, cyclopropyl, cyclohexyl, cyclodecanyl, bicyclooctyl, and adamantyl groups can be used.

[0153] Furthermore, in the phenyl group having substituents represented by the general formula (G1-2) above, the aromatic hydrocarbon group having 6 to 14 carbon atoms that forms the ring can be a substituted or unsubstituted phenyl group, naphthyl group, phenanthryl group, or fluorenyl group. The phenyl group is particularly preferred because it can lower the refractive index. The naphthyl group, phenanthryl group, and fluorenyl group are also preferred because they can raise the glass transition temperature. Moreover, substituting these ring-forming aromatic hydrocarbon groups having 6 to 14 carbon atoms with branched alkyl groups or cycloalkyl groups having 3 to 5 carbon atoms is preferred because it raises the glass transition temperature while simultaneously preventing an increase in refractive index (i.e., maintaining a low refractive index). Furthermore, from the viewpoint of reducing the refractive index, it is preferable that the above ring-forming aromatic hydrocarbon group having 6 to 14 carbon atoms is substituted with an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 14 carbon atoms that forms a ring substituted with an alkyl group having 1 to 6 carbon atoms or an alicyclic group having 3 to 10 carbon atoms. For example, phenyl groups substituted with alkyl groups having 1 to 6 carbon atoms or alicyclic groups having 3 to 10 carbon atoms are preferred, such as 1,3-di(t-butyl)phenyl group and 1,3-dicyclohexylphenyl group. Also preferred are phenyl groups substituted with alkyl groups having 1 to 6 carbon atoms or alicyclic groups having 3 to 10 carbon atoms, such as 3-t-butyl-5-[1,3-di(t-butyl)phenyl]phenyl group and 3-cyclohexyl-5-[1,3-dicyclohexylphenyl]phenyl group. Furthermore, when a fused ring is used and there are three or more fused rings, it is preferable that the other six-membered rings are fused only at the a, c, and e positions relative to the six-membered ring, as this allows for a lower refractive index compared to polyacene. For example, a phenanthrene ring can have a lower refractive index than an anthracene ring.

[0154] In each of the above configurations, the substituted phenyl group in the organic compound represented by general formula (G1), general formula (G2), general formula (G3), and general formula (G4) is preferably represented by the following general formula (G1-3).

[0155] [ka]

[0156] In the above general formula (G1-3), R 21 R represents one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or a substituent represented by the general formula (G1-3-1). 22 R represents a substituent represented by the general formula (G1-3-1). In the general formula (G1-3-1), 23 and R 24 R represents one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, or an alicyclic group having 3 to 10 carbon atoms. 23 and R 24 At least one of them is an alkyl group having 1 to 6 carbon atoms, or an alicyclic group having 3 to 10 carbon atoms. 23 and R 24 It is more preferable that both are alkyl groups having 1 to 6 carbon atoms, or alicyclic groups having 3 to 10 carbon atoms. Also, n represents 0 to 2. Note that if n is 2, multiple R 21 These can be the same or different. Note that if n is 0, R 23 and R 24 At least one of these is either an alkyl group having 1 to 6 carbon atoms, or an alicyclic group having 3 to 10 carbon atoms.

[0157] Furthermore, the phenyl group having substituents represented by the above general formula (G1-3) is R in general formula (G1) to (G4). 2 and R 4 It is preferable that either one or both of the above (however, the group represented by general formula (G1-3) is R 2 and R 4 If both conditions are met, the two groups represented by the above general formula (G1-3) may be the same or different.

[0158] Furthermore, in the phenyl group having substituents represented by the general formula (G1-3) above, the alkyl group having 1 to 6 carbon atoms can be a methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group, etc. In addition, the alicyclic group having 3 to 10 carbon atoms can be a cyclopropyl group, cyclohexyl group, cyclodecanyl group, bicyclooctyl group, adamantyl group, etc.

[0159] Furthermore, in the phenyl group having substituents represented by the above general formula (G1-3), the aromatic hydrocarbon group having 6 to 14 carbon atoms that forms the ring can be a substituted or unsubstituted phenyl group, naphthyl group, phenanthryl group, or fluorenyl group. The phenyl group is particularly preferred because it can lower the refractive index. The naphthyl group, phenanthryl group, and fluorenyl group are also preferred because they can raise the glass transition temperature. Moreover, substituting these ring-forming aromatic hydrocarbon groups having 6 to 14 carbon atoms with branched alkyl groups or cycloalkyl groups having 3 to 5 carbon atoms is preferred because it raises the glass transition temperature while simultaneously preventing an increase in refractive index (i.e., maintaining a low refractive index). Furthermore, from the viewpoint of reducing the refractive index, it is preferable that the above ring-forming aromatic hydrocarbon group having 6 to 14 carbon atoms is substituted with an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 14 carbon atoms that forms a ring substituted with an alkyl group having 1 to 6 carbon atoms or an alicyclic group having 3 to 10 carbon atoms. For example, phenyl groups substituted with alkyl groups having 1 to 6 carbon atoms or alicyclic groups having 3 to 10 carbon atoms are preferred, such as 1,3-di(t-butyl)phenyl group and 1,3-dicyclohexylphenyl group. Also preferred are phenyl groups substituted with alkyl groups having 1 to 6 carbon atoms or alicyclic groups having 3 to 10 carbon atoms, such as 3-t-butyl-5-[1,3-di(t-butyl)phenyl]phenyl group and 3-cyclohexyl-5-[1,3-dicyclohexylphenyl]phenyl group. Furthermore, when a fused ring is used and there are three or more fused rings, it is preferable that the other six-membered rings are fused only at the a, c, and e positions relative to the six-membered ring, as this allows for a lower refractive index compared to polyacene. For example, a phenanthrene ring can have a lower refractive index than an anthracene ring.

[0160] In each of the above configurations, in the organic compounds represented by general formula (G1), general formula (G2), general formula (G3), and general formula (G4), if the aromatic hydrocarbon group having 6 to 14 carbon atoms that forms a ring or the heteroaromatic ring group having 3 to 9 carbon atoms that forms a ring has substituents, it is preferable that the substituent is one of the following: an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an unsubstituted aromatic hydrocarbon group having 6 to 14 carbon atoms, or an aromatic hydrocarbon group having 6 to 14 carbon atoms that forms a ring substituted with an alkyl group having 1 to 6 carbon atoms or an alicyclic group having 3 to 10 carbon atoms. Examples of alkyl groups having 1 to 6 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, and hexyl groups. Examples of alicyclic groups having 3 to 10 carbon atoms include cyclopropyl, cyclohexyl, cyclodecanyl, bicyclooctyl, and adamantyl groups. Furthermore, as aromatic hydrocarbon groups having 6 to 14 carbon atoms, phenyl groups, naphthyl groups, phenanthryl groups, and fluorenyl groups can be used. Phenyl groups are particularly preferred because they can lower the refractive index. Naphthyl groups, phenanthryl groups, and fluorenyl groups are also preferred because they can raise the glass transition temperature. Moreover, substituting these ring-forming aromatic hydrocarbon groups having 6 to 14 carbon atoms with branched alkyl groups or cycloalkyl groups having 3 to 5 carbon atoms is preferred because it raises the glass transition temperature while simultaneously preventing an increase in refractive index (i.e., maintaining a low refractive index). Furthermore, from the viewpoint of reducing the refractive index, it is preferable that the above ring-forming aromatic hydrocarbon groups having 6 to 14 carbon atoms are substituted with alkyl groups having 1 to 6 carbon atoms, alicyclic groups having 3 to 10 carbon atoms, or aromatic hydrocarbon groups having 6 to 14 carbon atoms that form a ring substituted with alkyl groups having 1 to 6 carbon atoms or alicyclic groups having 3 to 10 carbon atoms. For example, phenyl groups substituted with alkyl groups having 1 to 6 carbon atoms, such as 1,3-di(t-butyl)phenyl groups and 1,3-dicyclohexylphenyl groups, or alicyclic groups having 3 to 10 carbon atoms are preferred.Furthermore, phenyl groups substituted with alkyl groups having 1 to 6 carbon atoms or alicyclic groups having 3 to 10 carbon atoms are preferred, such as 3-t-butyl-5-[1,3-di(t-butyl)phenyl]phenyl groups or 3-cyclohexyl-5-[1,3-dicyclohexylphenyl]phenyl groups. In addition, when fused rings are used and there are three or more fused rings, it is preferable that the other six-membered rings are fused only at the a, c, and e positions relative to the six-membered ring, as this allows for a lower refractive index compared to polyacene. For example, a phenanthrene ring can have a lower refractive index than an anthracene ring.

[0161] Furthermore, in each of the above configurations, the organic compounds represented by general formula (G1), general formula (G2), general formula (G3), and general formula (G4), and the aromatic hydrocarbon groups having 6 to 14 carbon atoms forming a ring in the phenyl groups having substituents represented by general formula (G1-2) and general formula (G1-3), are preferably represented by any one of the following formulas (ra-1) to (ra-15).

[0162] [ka]

[0163] In each of the above configurations, the substituted or unsubstituted pyridyl groups in the organic compounds represented by general formula (G1), general formula (G2), general formula (G3), and general formula (G4) are preferably unsubstituted pyridyl groups or pyridyl groups substituted with one or more methyl groups.

[0164] Another aspect of the present invention is an organic compound represented by the general formula (G4').

[0165] [ka]

[0166] In the above general formula (G4'), Q 1 ~Q 3Of these, 2 or 3 represent N, and Q 1 ~Q 3 If two of them are N, the remaining one represents CH. Also, R 2 This is expressed by the following formula (R 2 (-1) is expressed as R 4 , R 7 , R 9 , R 12 , R 14 Each of these independently represents one of the following equations (r-1) to (r-20). Note that equation (R 2 -1) In this case, β represents a substituted or unsubstituted phenylene group, or a substituted or unsubstituted biphenyldiyl group, R 25 represents one of the formulas (r-1) to (r-20), and n represents 1 or 2. The organic compound represented by the above general formula (G4') has multiple hydrocarbon groups selected from alkyl groups having 1 to 6 carbon atoms and alicyclic groups having 3 to 10 carbon atoms, and the ratio of the total number of carbon atoms forming bonds in sp3 hybrid orbitals to the total number of carbon atoms in the molecule is between 10% and 60%.

[0167] In the composition of the organic compound represented by the general formula (G4') above, the proportion of the total number of carbon atoms forming bonds in sp3 hybrid orbitals affects the refractive index of the organic compound. That is, as the total number of carbon atoms forming bonds in sp3 hybrid orbitals increases, the refractive index decreases, which can improve the light extraction efficiency of light-emitting devices using this compound. Furthermore, a higher total number of carbon atoms forming bonds in sp3 hybrid orbitals improves heat resistance, such as the glass transition temperature, which is desirable. However, if the total number of carbon atoms forming bonds in sp3 hybrid orbitals becomes too high, the overlap of LUMO orbitals between adjacent molecules in the organic compound is inhibited, reducing carrier transport properties (such as electron transport and injection). Therefore, the proportion of the total number of carbon atoms forming bonds in sp3 hybrid orbitals to the total number of carbon atoms in the molecule is preferably 10% to 60%, and more preferably 20% to 50%. Moreover, it is preferable that the proportion of the total number of carbon atoms forming bonds in sp3 hybrid orbitals to the total number of carbon atoms in the molecule be 20% to 40%.

[0168] Furthermore, the organic compound represented by the above general formula (G4') is Q 1 ~Q 3 When the compound is formed only of a six-membered heteroaromatic ring containing a six-membered aromatic ring (i.e., a substituted or unsubstituted phenyl group) and hydrocarbon groups (alkyl groups or alicyclic groups) that form bonds in sp3 hybrid orbitals (i.e., when no fused ring is included), the refractive index is lower and the carrier (electron) transportability is higher, which is preferable.

[0169] Furthermore, in the organic compound represented by the above general formula (G4'), Q 1 ~Q 3 As the six-membered ring containing the above formula (G4'), a pyridine ring or a triazine ring can be used. When the organic compound represented by the above general formula (G4') is used in a layer in contact with the luminescent layer or the active layer, a triazine ring, pyrazine ring, or pyrimidine ring is preferred, with a triazine ring being particularly preferred, as these rings readily implant electrons into these layers and have good electron transport properties.

[0170] [ka]

[0171] The above formula (R 2 -1) The β in this group can be a substituted or unsubstituted phenylene group, a biphenylene group, or a benzene-triyl group. If a substituent is present, an alkyl group having 1 to 6 carbon atoms or an alicyclic group having 3 to 10 carbon atoms can be used.

[0172] Furthermore, (R in the organic compound represented by the above general formula (G4') 2 The above formula (R 2 -1) R in the middle 25 is expressed by one of the following equations (r-1) to (r-20), and β is expressed by one of the following equations (β-1) to (β-14).

[0173] [ka]

[0174] [ka]

[0175] Next, specific examples of organic compounds having the above-described configurations, which represent one aspect of the present invention, are shown below.

[0176] [ka]

[0177] [ka]

[0178] [ka]

[0179] [ka]

[0180] [ka]

[0181] [ka]

[0182] [ka]

[0183] [ka]

[0184] [ka]

[0185]

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[0186]

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[0187]

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[0188]

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[0189]

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[0190]

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[0191]

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[0192]

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[0193]

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[0194]

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[0195] [ka]

[0196] In the above general formula (G1), it is preferable that the material consists only of a six-membered ring, an alkyl group, and an alicyclic group, as this allows for lower refractive index and visible region absorption, and when used as an electron transport material for optical devices, it is possible to maintain a low driving voltage.

[0197] In the above general formula (G1), if A is substituted with three substituted or unsubstituted phenyl groups, it is preferable that at least one of the phenyl groups does not contain substituents of an alkyl group or alicyclic group, as this allows for a lower driving voltage when used as an electron transport material in an electronic device. Examples include structural formulas (103), (107), (111), (116) to (129), (212) to (215), (218) to (221), (311) to (316), (412) to (417), and (600) to (605).

[0198] The organic compounds represented by structural formulas (100) to (129), (200) to (223), (300) to (317), (400) to (435), (500) to (506), and (600) to (605) are examples of organic compounds represented by the general formula (G1), but the organic compounds in one aspect of the present invention are not limited to these.

[0199] Next, an embodiment of the present invention, a method for synthesizing an organic compound represented by the following general formula (G1), will be described.

[0200] [ka]

[0201] In the above general formula (G1), A represents a six-membered heteroaromatic ring containing one to three nitrogen atoms. Also, R 0R represents hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or a substituent represented by formula (G1-1). 1 ~R 15 At least one of the atoms is a substituted phenyl group, and the others each independently represent one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 14 carbon atoms forming a substituted or unsubstituted ring, or a substituted or unsubstituted pyridyl group. The substituted phenyl group has one or two substituents, and each substituent is independently one of the following: an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 14 carbon atoms forming a substituted or unsubstituted ring, or a heteroaromatic ring group having 3 to 9 carbon atoms forming a substituted or unsubstituted ring. The organic compound represented by the above general formula (G1) has multiple hydrocarbon groups selected from alkyl groups having 1 to 6 carbon atoms and alicyclic groups having 3 to 10 carbon atoms, and the ratio of the total number of carbon atoms forming bonds in sp3 hybrid orbitals to the total number of carbon atoms in the molecule is 10% to 60%.

[0202] ≪Synthesis method for organic compounds represented by general formula (G1)≫ Below is an example of a method for synthesizing organic compounds represented by general formula (G1). Various reactions can be applied to the synthesis of these organic compounds. For example, as shown in synthesis scheme (A-1), compound (a4) can be obtained by reacting aryl halide (a1) with aryl halides (a2) and (a3). In the above reaction, aryl halides (a2) and (a3) ​​are used as Grignard reagents or lithium compounds, and compound (a4) is obtained by reacting aryl halide (a1) in an ether solvent.

[0203] [ka]

[0204] In the formula, A represents a six-membered heteroaromatic ring containing one to three nitrogen atoms. Also, R 1 ~R 10 At least one of the atoms is a substituted phenyl group, and the others each independently represent one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 14 carbon atoms forming a substituted or unsubstituted ring, or a substituted or unsubstituted pyridyl group. The substituted phenyl group has one or two substituents, and each substituent is independently one of the following: an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 14 carbon atoms forming a substituted or unsubstituted ring, or a heteroaromatic ring group having 3 to 9 carbon atoms forming a substituted or unsubstituted ring. Also, X 1 ~X 5 Each of these independently represents either chlorine, bromine, or iodine.

[0205] In the above reaction, it is preferable to use aryl halides (a2) and (a3) ​​with the same structure to increase the yield of aryl halide (a4). However, if the structures of aryl halides (a2) and (a3) ​​are different, the yield of compound (a4) can be increased by dividing the synthesis steps into two or more steps, such as reacting aryl halide (a1) with aryl halide (a2) in the first step, and then reacting the resulting product with aryl halide (a3) ​​in the second step.

[0206] Note that R in the general formula (G1) 0 If it is hydrogen, X 3 By replacing with hydrogen, the organic compound represented by general formula (G1) can be synthesized using synthesis scheme (A-1).

[0207] Next, as shown in the synthesis scheme (A-2) below, the target compound (G1) can be synthesized by coupling an aryl halide (a4) with an arylboron compound (a5). In this reaction, a synthesis method using a metal catalyst in the presence of a base can be used; for example, the Suzuki-Miyaura reaction can be used.

[0208] [ka]

[0209] In the formula, A represents a six-membered heteroaromatic ring containing one to three nitrogen atoms. Also, R 0 R represents the substituent represented by formula (G1-1). 1 ~R 15 At least one of the atoms is a substituted phenyl group, and the others each independently represent one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 14 carbon atoms forming a substituted or unsubstituted ring, or a substituted or unsubstituted pyridyl group. The substituted phenyl group has one or two substituents, and each substituent is each independently one of the following: an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 14 carbon atoms forming a substituted or unsubstituted ring, or a heteroaromatic ring group having 3 to 9 carbon atoms forming a substituted or unsubstituted ring. 1 This represents boronic acid esters such as boronic acid and pinacolboron. 3 X is one of chlorine, bromine, or iodine, and using the one with the higher atomic number is preferable because it increases reactivity. 3 Boronic acid and boronic acid esters such as pinacol boron, Y 1 These can also be reacted with halogens or sulfonyloxy groups.

[0210] Also R 0However, in the case of alkyl groups having 1 to 6 carbon atoms, or alicyclic groups having 3 to 10 carbon atoms, compound (a4) can be obtained by reacting a Grignard reagent or lithium compound of these alkyl or alicyclic groups with aryl halide (a4) in an ether solvent using a metal catalyst. For example, the Kumada-Tamao-Colieu coupling can be used.

[0211] In addition, in the above synthesis scheme (A-1), the aryl halide (a1) may be reacted with the arylboron compound (a5) first, and the resulting compound may be reacted with the aryl halides (a2) and (a3). Furthermore, if the three substituents bonded to A of the target product (G1) all have the same structure, these three substituents and the X of the aryl halide (a1) in the first step may be reacted. 1 ~X 3 Substituting and respectively and then performing a coupling reaction can reduce synthesis costs, which is preferable.

[0212] Alternatively, as shown in the synthesis scheme (B-1) below, the target compound (G1) can be synthesized by coupling an aryl halide ((b1)+(b1-1)) with an arylboron compound (b2). In this reaction, a synthesis method using a metal catalyst in the presence of a base can be used; for example, the Suzuki-Miyaura reaction can be used.

[0213] [ka]

[0214] In the formula, A represents a six-membered heteroaromatic ring containing one to three nitrogen atoms. Also, R 0 R represents one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or a substituent represented by formula (G1-1). 1 ~R 15At least one of the atoms is a substituted phenyl group, and the others each independently represent one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 14 carbon atoms forming a substituted or unsubstituted ring, or a substituted or unsubstituted pyridyl group. The substituted phenyl group has one or two substituents, and each substituent is each independently one of the following: an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 14 carbon atoms forming a substituted or unsubstituted ring, or a heteroaromatic ring group having 3 to 9 carbon atoms forming a substituted or unsubstituted ring. 2 This represents boronic acid esters such as boronic acid and pinacolboron. 4 X represents chlorine, bromine, iodine, or a sulfonyloxy group, and using the one with the larger atomic number is preferable because it increases reactivity. 4 Boronic acid and boronic acid esters such as pinacol boron, Y 2 These can also be reacted with halogens or sulfonyloxy groups.

[0215] In this synthesis scheme, the R of the arylboron compound (b2) 12 The Y substituent (b1-1) of the aryl halide ((b1)+(b1-1)) 2 We have shown an example of a reaction in which substitution occurs, but a similar reaction can be performed with aryl halides ((b1)+(b1-1)) R 1 ~R 11 , R 13 ~R 15 You can also do it at the substitution position.

[0216] The above describes an example of a method for synthesizing an organic compound, which is one aspect of the present invention. However, the present invention is not limited thereto, and the compound may be synthesized by any other method.

[0217] The configuration shown in this embodiment can be used in appropriate combination with the configurations shown in other embodiments.

[0218] (Embodiment 2)

[0219] Figure 1(A) shows a diagram representing a light-emitting device according to one embodiment of the present invention. The light-emitting device according to one embodiment of the present invention has a first electrode 101, a second electrode 102, and an EL layer 103, and the EL layer uses the electron transport layer material shown in Embodiment 1 or the organic compound shown in Embodiment 1.

[0220] The EL layer 103 has an emissive layer 113 and may also have a hole injection layer 111 and / or a hole transport layer 112. The emissive layer 113 contains an emissive material, and a light-emitting device according to one embodiment of the present invention obtains light from the emissive material. The emissive layer 113 may also contain a host material or other materials. The electron transport layer material shown in Embodiment 1 is included in the electron transport layer 114 and / or the electron injection layer 115. The organic compound shown in Embodiment 1 may be included in the emissive layer 113, the electron transport layer 114, the electron injection layer 115, or any of these.

[0221] Although Figure 1(A) also shows a hole injection layer 111 and a hole transport layer 112, the configuration of the light-emitting device is not limited to these. For example, an electron blocking layer may be provided between the hole transport layer 112 and the light-emitting layer 113, or a hole blocking layer may be provided between the light-emitting layer 113 and the electron transport layer 114.

[0222] The electron transport layer material or organic compound is effective for use in the electron transport layer 114 because it has good electron transport properties. Furthermore, a configuration in which the electron transport layer material or organic compound according to one aspect of the present invention is mixed with an alkali metal organometallic complex and used in the electron transport layer 114 and / or electron injection layer 115 is a preferred configuration because it improves the driving voltage and luminous efficiency.

[0223] Furthermore, the organic compound according to one embodiment of the present invention can also be used as a host material. In this case, the organic compound may be co-deposited with a hole transport material to form an excited complex with the hole transport material. By forming an excited complex with an appropriate emission wavelength, it is possible to achieve effective energy transfer to the light-emitting material and provide a light-emitting device with high efficiency and a good lifespan.

[0224] Since the organic compound in one aspect of the present invention is an organic compound with a low refractive index, by using it inside the EL layer, a light-emitting device with good external quantum efficiency can be obtained.

[0225] Next, we will describe the detailed structure and examples of materials of the light-emitting device described above. In one embodiment of the present invention, as described above, the light-emitting device has an EL layer 103 consisting of multiple layers between a pair of electrodes, a first electrode 101 and a second electrode 102, and any portion of the EL layer 103 contains the electron transport layer material or organic compound disclosed in Embodiment 1.

[0226] The first electrode 101 is preferably formed using a metal, alloy, conductive compound, or mixture thereof with a large work function (specifically, 4.0 eV or more). Specifically, examples include indium tin oxide (ITO), indium tin oxide containing silicon or silicon oxide, indium zinc oxide, and indium oxide (IWZO) containing tungsten oxide and zinc oxide. These conductive metal oxide films are usually deposited by sputtering, but they may also be fabricated using methods such as the sol-gel method. As an example of a fabrication method, indium zinc oxide can be formed by sputtering using a target containing 1 to 20 wt% zinc oxide relative to indium oxide. Indium oxide (IWZO) containing tungsten oxide and zinc oxide can also be formed by sputtering using a target containing 0.5 to 5 wt% tungsten oxide and 0.1 to 1 wt% zinc oxide relative to indium oxide. Other materials include gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), or nitrides of metallic materials (e.g., titanium nitride). Graphene can also be used. Furthermore, by using the composite material described later in the layer in contact with the first electrode 101 in the EL layer 103, the electrode material can be selected regardless of the work function.

[0227] The EL layer 103 preferably has a multilayer structure, but there are no particular limitations on the multilayer structure, and various layer structures such as hole injection layers, hole transport layers, electron transport layers, electron injection layers, carrier block layers (hole block layers, electron block layers), exciton block layers, and charge generation layers can be applied. In this embodiment, two types of configurations will be described: one having an electron transport layer 114, an electron injection layer 115, and an emissive layer 113, in addition to a hole injection layer 111 and a hole transport layer 112, as shown in Figure 1(A); and one having an electron transport layer 114, an electron injection layer 115, an emissive layer 113, a hole injection layer 111, a hole transport layer 112, in addition to a charge generation layer 116, as shown in Figure 1(B). The materials constituting each layer are specifically described below.

[0228] The hole injection layer 111 is a layer containing an acceptor substance. Both organic and inorganic compounds can be used as the acceptor substance.

[0229] Examples of substances with acceptor properties include compounds having electron-withdrawing groups (halogen groups or cyano groups), such as 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviated as F4-TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviated as HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviated as F6-TCNNQ), and 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyrene-2-ylidene)malononitrile. In particular, compounds in which an electron-withdrawing group is bonded to a condensed aromatic ring having multiple heteroatoms, such as HAT-CN, are thermally stable and preferred. Furthermore, radialene derivatives having an electron-withdrawing group (especially halogen groups such as fluoro groups or cyano groups) are preferred because they have very high electron-accepting properties. Specific examples include α,α',α''-1,2,3-cyclopropanetriylidenates[4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α',α''-1,2,3-cyclopropanetriylidenates[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], and α,α',α''-1,2,3-cyclopropanetriylidenates[2,3,4,5,6-pentafluorobenzeneacetonitrile]. In addition to the organic compounds mentioned above, other substances with acceptor properties that can be used include molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide. Furthermore, the hole injection layer 111 can also be formed using phthalocyanine-based complex compounds such as phthalocyanine (abbreviated as H2Pc) and copper phthalocyanine (CuPc), aromatic amine compounds such as 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB) and N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviated as DNTPD), or polymers such as poly(3,4-ethylenedioxythiophene) / poly(styrene sulfonic acid) (PEDOT / PSS).Acceptor materials can extract electrons from adjacent hole transport layers (or hole transport materials) by applying an electric field.

[0230] Furthermore, a composite material containing the above-mentioned acceptor substance in a hole-transporting material can also be used as the hole injection layer 111. By using a composite material containing the acceptor substance in a hole-transporting material, it is possible to select the material for forming the electrode regardless of the work function. In other words, not only materials with a large work function but also materials with a small work function can be used as the first electrode 101.

[0231] Various organic compounds can be used as hole-transporting materials in composite materials, including aromatic amine compounds, carbazole derivatives, aromatic hydrocarbons, and polymer compounds (oligomers, dendrimers, polymers, etc.). -6 cm 2 It is preferable that the material has a hole mobility of / Vs or higher. Below, we specifically list organic compounds that can be used as hole transporting materials in composite materials.

[0232] Aromatic amine compounds that can be used in composite materials include N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviated as DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB), N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviated as DNTPD), and 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviated as DPA3B). Specifically, carbazole derivatives include 3-[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviated as PCzPCA1), 3,6-bis[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviated as PCzPCA2), and 3-[N-(1-naphthyl)-N-(9-phenylcarbazole-3-yl)amino]-9-phenylcarbazole Examples of substances that can be used include bazole (abbreviated as PCzPCN1), 4,4'-di(N-carbazolyl)biphenyl (abbreviated as CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviated as TCPB), 9-[4-(10-phenylanthracene-9-yl)phenyl]-9H-carbazole (abbreviated as CzPA), and 1,4-bis[4-(N-carbazolyl)phenyl]-2,3,5,6-tetraphenylbenzene.Examples of aromatic hydrocarbons include 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 2-tert-butyl-9,10-di(1-naphthyl)anthracene, 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 2-tert-butyl-9,10-bis(4-phenylphenyl)anthracene (abbreviation: t-BuDBA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 9,10-diphenylanthracene (abbreviation: DPAnth), 2-tert-butylanthracene (abbreviation: t-BuAnth), 9,10-bis(4-methyl-1-naphthyl)anthracene (abbreviation: DMNA), 2-tert- Examples include butyl-9,10-bis[2-(1-naphthyl)phenyl]anthracene, 9,10-bis[2-(1-naphthyl)phenyl]anthracene, 2,3,6,7-tetramethyl-9,10-di(1-naphthyl)anthracene, 2,3,6,7-tetramethyl-9,10-di(2-naphthyl)anthracene, 9,9'-bianthryl, 10,10'-diphenyl-9,9'-bianthryl, 10,10'-bis(2-phenylphenyl)-9,9'-bianthryl, 10,10'-bis[(2,3,4,5,6-pentaphenyl)phenyl]-9,9'-bianthryl, anthracene, tetracene, rubrene, perylene, and 2,5,8,11-tetra(tert-butyl)perylene. In addition, pentacene, coronene, and the like can also be used. The compound may have a vinyl skeleton. Examples of aromatic hydrocarbons having a vinyl group include 4,4'-bis(2,2-diphenylvinyl)biphenyl (abbreviated as DPVBi) and 9,10-bis[4-(2,2-diphenylvinyl)phenyl]anthracene (abbreviated as DPVPA). An organic compound according to one embodiment of the present invention can also be used.

[0233] In addition, polymer compounds such as poly(N-vinylcarbazole) (abbreviated as PVK), poly(4-vinyltriphenylamine) (abbreviated as PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviated as PTPDMA), and poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviated as Poly-TPD) can also be used.

[0234] The hole-transporting material used in the composite material is more preferably one of the following: a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, or an anthracene skeleton. In particular, it may be an aromatic amine having substituents including a dibenzofuran ring or a dibenzothiophene ring, an aromatic monoamine having a naphthalene ring, or an aromatic monoamine in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group. Furthermore, it is preferable that these organic compounds are substances having an N,N-bis(4-biphenyl)amino group, as this allows for the creation of light-emitting devices with a good lifetime. Specifically, the organic compounds described above include N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BnfABP), N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf), and 4,4'-bis(6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine). ru-4''-phenyltriphenylamine (abbreviation: BnfBB1BP), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-6-amine (abbreviation: BBABnf(6)), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-8-amine (abbreviation: BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-6-amine (abbreviation: BBABnf(6)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-8-amine (abbreviation: BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-6-amine (abbreviation: BnfBB1BP), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-8-amine (abbreviation: BBABnf(6 N-4-amine (abbreviation: BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(dibenzothiophen-4-yl)phenyl]-N-phenyl-4-biphenylamine (abbreviation: ThBA1BP), 4-(2-naphthyl)-4',4''-diphenyltriphenylamine (abbreviation: BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4''-diphenyltriphenylamine (abbreviation: BBAβNBi), 4,4'-diphenyl-4''-(6;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB), 4,4'-diphenyl-4''-(7;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB-03), 4,4'-Diphenyl-4''-(7-phenyl)naphthyl-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4,4'-Diphenyl-4''-(6;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B), 4,4'-Diphenyl-4''-(7;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-Diphenyl-4''-(4;2'-binaphthyl-1 -yl)triphenylamine (abbreviation: BBAβNαNB), 4,4'-diphenyl-4''-(5;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenylyl)-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: TPBiAβNB), 4-(3-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: mTPB) iAβNBi), 4-(4-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: TPBiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenylamine (abbreviation: αNBA1BP), 4,4'-bis(1-naphthyl)triphenylamine (abbreviation: αNBB1BP), 4,4'-diphenyl-4''-[4'-(carbazole-9-yl)biphenyl-4-yl]triphenyl Luamine (abbreviation: YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazole-9-yl)phenyl]tris(1,1'-biphenyl-4-yl)amine (abbreviation: YGTBi1BP-02), 4-[4'-(carbazole-9-yl)biphenyl-4-yl]-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: YGTBiβNB), N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl] -N-[4-(1-naphthyl)phenyl]-9,9'-spirobio(9H-fluorene)-2-amine (abbreviation: PCBNBSF), N,N-bis([1,1'-biphenyl]-4-yl)-9,9'-spirobio[9H-fluorene]-2-amine (abbreviation: BBASF), N,N-bis(1,1'-biphenyl-4-yl)-9,9'-spirobio[9H-fluorene]-4-amine (abbreviation: BBASF(4)), N-(1,1'-biphenyl-2-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi(9H-fluoren)-4-amine (abbreviation: oFBiSF), N-(4-biphenyl)-N-(9,9-dimethyl-9H-fluoren-2-yl)dibenzofuran-4-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4-phenyl-4'-(9-phenylfluoren-9-yl) Riphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-[4-(9-phenylfluoren-9-yl)phenyl]triphenylamine (abbreviation: BPAFLBi), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBNBB), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirobio[9H-fluorene]-2-amine (abbreviation: PCBASF), N-(1,1'-biphenyl-4-yl)-9,9-dimethyl-N-[4-(9-phenyl-9H- Carbazole-3-yl)phenyl]-9H-fluoren-2-amine (abbreviation: PCBBiF), N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobio-9H-fluoren-4-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobio-9H-fluoren-3-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobio-9H-fluoren-2-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,Examples include 9'-spirobio-9H-fluoren-1-amine.

[0235] Furthermore, it is even more preferable that the hole-transporting material used in the composite material has a relatively deep HOMO level, with its Highest Occupied Molecular Orbital (HOMO) level being between -5.7 eV and -5.4 eV. Having a relatively deep HOMO level in the hole-transporting material used in the composite material facilitates the injection of holes into the hole transport layer 112 and makes it easier to obtain a light-emitting device with a good lifetime.

[0236] Furthermore, by mixing alkali metal or alkaline earth metal fluoride into the above composite material (preferably with an atomic ratio of fluorine atoms of 20% or more in the layer), the refractive index of the layer can be reduced. This also makes it possible to form a layer with a low refractive index inside the EL layer 103, thereby improving the external quantum efficiency of the light-emitting device.

[0237] By forming the hole injection layer 111, the hole injection performance is improved, making it possible to obtain a light-emitting device with a low driving voltage. Furthermore, organic compounds with acceptor properties are easy to deposit and form films with, making them easy to use materials.

[0238] The hole transport layer 112 is formed by including a material having hole transport properties. The material having hole transport properties is 1 × 10 -6 cm 2 It is preferable that the hole mobility is greater than or equal to / Vs.

[0239] Materials possessing the above-mentioned hole transport properties include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated as NPB), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviated as TPD), 4,4'-bis[N-(spiro-9,9'-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviated as BSPB), and 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviated as BPA). FLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCB Aromatic amino acids such as ANB, 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]fluoren-2-amine (abbreviated as PCBAF), and N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirobio[9H-fluoren]-2-amine (abbreviated as PCBASF). Compounds with a carbazole skeleton, such as 1,3-bis(N-carbazolyl)benzene (abbreviated as mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviated as CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviated as CzTP), 3,3'-bis(9-phenyl-9H-carbazole) (abbreviated as PCCP), and 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviated as DBT3P-II), 2,Examples include compounds having a thiophene skeleton such as 8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviated as DBTFLP-III) and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviated as DBTFLP-IV), and compounds having a furan skeleton such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviated as DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviated as mmDBFFLBi-II). Among the above, compounds having an aromatic amine skeleton and compounds having a carbazole skeleton are preferred because they have good reliability, high hole transportability, and contribute to reducing the driving voltage. Furthermore, the materials listed as having hole-transporting properties used in the composite material of the hole injection layer 111 can also be suitably used as materials constituting the hole transport layer 112.

[0240] The light-emitting layer 113 contains a light-emitting substance and a host material. The light-emitting layer 113 may also contain other materials. Furthermore, it may be a laminate of two layers with different compositions.

[0241] The luminescent material may be a fluorescent material, a phosphorescent material, a material exhibiting thermally activated delayed fluorescence (TADF), or any other luminescent material. One aspect of the present invention can be more preferably applied when the luminescent layer 113 is a layer that exhibits fluorescent emission, particularly a layer that exhibits blue fluorescent emission.

[0242] Examples of materials that can be used as fluorescent materials in the light-emitting layer 113 include the following. Other fluorescent materials can also be used.

[0243] 5,6-Bis[4-(10-phenyl-9-antryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-Bis[4'-(10-phenyl-9-antryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-Diphenyl-N,N'-Bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyren-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-Bis(3-methylphenyl)-N,N'-Bis[3-(9-phenyl-9H-fluoren-9-yl )phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-bis[4-(9H-carbazole-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazole-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazole-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-( 10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra-tert-butylperylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBAPA), N,N''-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene)bis[N,N',N'-triphenyl-1,4-phenylenediamine] (abbreviation: DPABPA), N,9 -Diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), N,N,N',N',N'',N'',N''',N'''-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), coumarin 30, N-(9,10-diphenyl-2-anthryl)-N,9-Diphenyl-9H-carbazole-3-amine (abbreviation: 2PCAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCABPhA), N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthryl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPA BPhA), 9,10-bis(1,1'-biphenyl-2-yl)-N-[4-(9H-carbazole-9-yl)phenyl]-N-phenylanthracene-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracene-9-amine (abbreviation: DPhAPhA), coumarin 545T, N,N'-diphenylquinacridone (abbreviation: DPQd), rubren, 5,12-bis(1,1'-biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6 -methyl-4H-pyran-4-ylidene)propanedinitrile (abbreviation: DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N',N'-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluorantene-3,10-di Amine (abbreviation: p-mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2,6-Bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propanedinitrile (abbreviation: BisDCM), 2-{2,6-Bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), N,N'-diphenyl-N,N'-(1,6-pyrene-diyl)bis[(6-phenylbenzo[b Examples include ]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), 3,10-bis[N-(9-phenyl-9H-carbazole-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02), and 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10FrA2Nbf(IV)-02). In particular, condensed aromatic diamine compounds, such as pyrenediamine compounds like 1,6FLPAPrn, 1,6mMemFLPAPrn, and 1,6BnfAPrn-03, are preferred because they have high hole-trapping properties and excellent luminescence efficiency and reliability.

[0244] When a phosphorescent material is used as the light-emitting material in the light-emitting layer 113, the following are some examples of materials that can be used.

[0245] Organometallic iridium complexes having a 4H-triazole skeleton, such as Tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN2]phenyl-κC}iridium(III) (abbreviation: [Ir(mpptz-dmp)3]), Tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Mptz)3]), Tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(iPrptz-3b)3]), and Tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III) ( Organometallic iridium complexes having a 1H-triazole skeleton, such as tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III) (abbreviated as [Ir(Prptz1-Me)3]), or organometallic iridium complexes having an imidazole skeleton, such as fac-tris[(1-2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviated as [Ir(iPrpmi)3]), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridine]iridium(III) (abbreviated as [Ir(dmpimpt-Me)3]), or bis[2-(4',6'-difluorophenyl)pyridinate-N,C 2’ Iridium(III) tetrakis(1-pyrazolyl) borate (abbreviation: FIr6), bis[2-(4',6'-difluorophenyl)pyridinate-N,C 2’ Iridium(III) picolinate (abbreviation: Firpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinate-N,C 2’ Iridium(III) picolinate (abbreviation: [Ir(CF3ppy)2(pic)]), bis[2-(4',6'-difluorophenyl)pyridinate-N,C 2’Examples include organometallic iridium complexes that use phenylpyridine derivatives having electron-withdrawing groups, such as iridium(III) acetylacetonate (abbreviated as FIracac), as ligands. These compounds exhibit blue phosphorescence and have emission peaks between 440 nm and 520 nm.

[0246] Also, tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)3]), tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)3]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)2(acac)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm)2(acac)]), (acetylacetonato)bis[5-methyl-6-( Organometallic iridium complexes having a pyrimidine skeleton, such as [2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(mpmppm)2(acac)]), (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm)2(acac)]), organometallic iridium complexes having a pyrazine skeleton, such as [acetylacetonato]bis(3,5-dimethyl-2-phenylpyradinato)iridium(III) (abbreviation: [Ir(mppr-Me)2(acac)]), (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyradinato)iridium(III) (abbreviation: [Ir(mppr-iPr)2(acac)]), and tris(2-phenylpyridinato-N,C 2’ Iridium(III) (abbreviation: [Ir(ppy)3]), bis(2-phenylpyridinate-N,C) 2’Iridium(III) acetylacetonate (abbreviation: [Ir(ppy)2(acac)]), bis(benzo[h]quinolinate)iridium(III) acetylacetonate (abbreviation: [Ir(bzq)2(acac)]), tris(benzo[h]quinolinate)iridium(III) (abbreviation: [Ir(bzq)3]), tris(2-phenylquinolinate-N,C) 2’ Iridium(III) (abbreviation: [Ir(pq)3]), bis(2-phenylquinolinato-N,C) 2’ Examples include organometallic iridium complexes with a pyridine skeleton, such as iridium(III) acetylacetonate (abbreviated as [Ir(pq)2(acac)]), and rare earth metal complexes, such as tris(acetylacetonate)(monophenanthroline)terbium(III) (abbreviated as [Tb(acac)3(Phen)]). These compounds mainly exhibit green phosphorescence and have an emission peak in the 500nm-600nm range. Organometallic iridium complexes with a pyrimidine skeleton are particularly preferred due to their outstanding reliability and luminescence efficiency.

[0247] Furthermore, organometallic iridium complexes having a pyrimidine skeleton, such as (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [Ir(5mdppm)2(dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipvaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm)2(dpm)]), and bis[4,6-di(naphthalene-1-yl)pyrimidinato](dipvaloylmethanato)iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]), Organometallic iridium complexes with a pyrazine skeleton, such as (acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III) (abbreviation: [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato)iridium(III) (abbreviation: [Ir(tppr)2(dpm)]), and (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq)2(acac)]), as well as tris(1-phenylisoquinolinato-N,C) 2’ Iridium(III) (abbreviation: [Ir(piq)3]), bis(1-phenylisoquinolinato-N,C) 2’ Examples include organometallic iridium complexes with a pyridine skeleton, such as iridium(III) acetylacetonate (abbreviated as [Ir(piq)2(acac)]), as well as platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (abbreviated as PtOEP), and rare earth metal complexes such as tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviated as [Eu(DBM)3(Phen)]) and tris[1-(2-tenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III) (abbreviated as [Eu(TTA)3(Phen)]). These compounds exhibit red phosphorescence and have an emission peak between 600 nm and 700 nm. Furthermore, organometallic iridium complexes with a pyrazine skeleton produce a red emission with good chromaticity.

[0248] In addition to the phosphorescent compounds described above, other known phosphorescent substances may be selected and used.

[0249] As TADF materials, fullerenes and their derivatives, acridines and their derivatives, eosin derivatives, etc., can be used. Also, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd) can be used. Examples of metal-containing porphyrins include protoporphyrin-tin fluoride complexes (SnF2(Proto IX)), mesoporphyrin-tin fluoride complexes (SnF2(Meso IX)), hematoporphyrin-tin fluoride complexes (SnF2(Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complexes (SnF2(Copro III-4Me)), octaethylporphyrin-tin fluoride complexes (SnF2(OEP)), etioporphyrin-tin fluoride complexes (SnF2(Etio I)), and octaethylporphyrin-platinum chloride complexes (PtCl2OEP), as shown in the following structural formulas.

[0250] [ka]

[0251] Furthermore, there are 2-(biphenyl-4-yl)-4,6-bis(12-phenylindoro[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviated as PIC-TRZ), 9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviated as PCCzTzn), 9-[4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviated as PCCzPTzn), and 2-[4-(10H-phenoxazine-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviated as P Heterocyclic compounds having one or both of a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring can also be used, such as XZ-TRZ, 3-[4-(5-phenyl-5,10-dihydrophenazine-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviated as PPZ-3TPT), 3-(9,9-dimethyl-9H-acridine-10-yl)-9H-xanthene-9-one (abbreviated as ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviated as DMAC-DPS), and 10-phenyl-10H,10'H-spiro[acridine-9,9'-anthracene]-10'-one (abbreviated as ACRSA). The heterocyclic compound is preferred because it has both a π-electron-excess heteroaromatic ring and a π-electron-deficient heteroaromatic ring, resulting in high electron transport and hole transport properties. Among the skeletons having a π-electron-deficient heteroaromatic ring, the pyridine skeleton, diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), and triazine skeleton are preferred because they are stable and reliable. In particular, the benzoflopyrimidine skeleton, benzothienopyrimidine skeleton, benzoflopyrazine skeleton, and benzothienopyrazine skeleton are preferred because they have high acceptor properties and are reliable. Furthermore, among the skeletons having a π-electron-excess heteroaromatic ring, the acridine skeleton, phenoxazine skeleton, phenothiazine skeleton, furan skeleton, thiophene skeleton, and pyrrole skeleton are preferred because they are stable and reliable, and therefore it is preferable to have at least one of these skeletons.Furthermore, a dibenzofuran skeleton is preferred as the furan skeleton, and a dibenzothiophene skeleton is preferred as the thiophene skeleton. In addition, as the pyrrole skeleton, indole skeleton, carbazole skeleton, indrocarbazole skeleton, bicarbazole skeleton, and 3-(9-phenyl-9H-carbazole-3-yl)-9H-carbazole skeleton are particularly preferred. Substances in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded are particularly preferred because both the electron-donating and electron-accepting properties of the π-electron-rich heteroaromatic ring are strengthened, and the energy difference between the S1 and T1 levels is reduced, thus efficiently obtaining thermally activated delayed fluorescence. In addition, an aromatic ring to which an electron-withdrawing group such as a cyano group is bonded may be used instead of the π-electron-deficient heteroaromatic ring. Furthermore, aromatic amine skeletons, phenazine skeletons, etc., can be used as the π-electron-rich skeleton. Furthermore, as π-electron-deficient skeletons, xanthene skeletons, thioxanthene dioxide skeletons, oxadiazole skeletons, triazole skeletons, imidazole skeletons, anthraquinone skeletons, boron-containing skeletons such as phenylborane and volanthrene, aromatic rings or heteroaromatic rings having a nitrile group or a cyano group such as benzonitrile or cyanobenzene, carbonyl skeletons such as benzophenone, phosphine oxide skeletons, sulfone skeletons, etc., can be used. In this way, π-electron-deficient skeletons and π-electron-excess skeletons can be used instead of at least one of π-electron-deficient heteroaromatic rings and π-electron-excess heteroaromatic rings.

[0252] [ka]

[0253] TADF materials are materials that have a small difference between the S1 and T1 energy levels and possess the ability to convert energy from triplet excitation energy to singlet excitation energy through reverse intersystem crossing. Therefore, triplet excitation energy can be upconverted to singlet excitation energy with only a small amount of thermal energy (reverse intersystem crossing), and singlet excited states can be efficiently generated. Furthermore, triplet excitation energy can be converted into luminescence.

[0254] Furthermore, an excited complex (also called an exciplex) that forms an excited state with two types of substances has an extremely small difference between the S1 and T1 levels and functions as a TADF material that can convert triplet excitation energy into singlet excitation energy.

[0255] Furthermore, the phosphorescence spectrum observed at low temperatures (e.g., 77K to 10K) can be used as an indicator of the T1 level. For TADF materials, when a tangent is drawn at the short-wavelength tail of the fluorescence spectrum and the energy at the wavelength of the extrapolation is taken as the S1 level, and when a tangent is drawn at the short-wavelength tail of the phosphorescence spectrum and the energy at the wavelength of the extrapolation is taken as the T1 level, it is preferable that the difference between S1 and T1 is 0.3 eV or less, and more preferably 0.2 eV or less.

[0256] Furthermore, when using TADF material as a light-emitting material, it is preferable that the S1 level of the host material is higher than the S1 level of the TADF material. Also, it is preferable that the T1 level of the host material is higher than the T1 level of the TADF material.

[0257] Various carrier transport materials can be used as the host material for the light-emitting layer, such as materials with electron transport properties, materials with hole transport properties, and the TADF material mentioned above.

[0258] As materials possessing hole transport properties, organic compounds having an amine skeleton or a π-electron-rich heteroaromatic ring skeleton are preferred. For example, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated as NPB), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviated as TPD), 4,4'-bis[N-(spiro-9,9'-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviated as BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviated as BPAFLP), 4-phenyl Lu-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBANB), 4, Aromatic amine skeletons such as 4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), and N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirobio[9H-fluoren]-2-amine (abbreviation: PCBASF). Compounds containing, and compounds having a carbazole skeleton such as 1,3-bis(N-carbazolyl)benzene (abbreviated as mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviated as CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviated as CzTP), 3,3'-bis(9-phenyl-9H-carbazole) (abbreviated as PCCP), and 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviated as DBT3P-II), 2,Examples include compounds having a thiophene skeleton such as 8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviated as DBTFLP-III) and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviated as DBTFLP-IV), and compounds having a furan skeleton such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviated as DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviated as mmDBFFLBi-II). Among the above, compounds having an aromatic amine skeleton and compounds having a carbazole skeleton are preferred because they have good reliability, high hole transportability, and contribute to reducing the driving voltage. In addition, organic compounds listed as examples of hole transportable materials in the hole transport layer 112 can also be used. ,

[0259] Preferred materials with electron transport properties include metal complexes such as bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviated as BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviated as BAlq), bis(8-quinolinolato)zinc(II) (abbreviated as Znq), bis[2-(2-benzoxazollyl)phenolato]zinc(II) (abbreviated as ZnPBO), and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviated as ZnBTZ), as well as organic compounds having a π-electron-deficient heteroaromatic ring skeleton.Examples of organic compounds having a π-electron-deficient heteroaromatic ring skeleton include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviated as PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviated as TAZ), and 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene (abbreviated as OXD-7). Heterocyclic compounds having a polyazole skeleton, such as 9-[4-(5-phenyl-1,3,4-oxadiazole-2-yl)phenyl]-9H-carbazole (abbreviated as CO11), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzoimidazole) (abbreviated as TPBI), and 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzoimidazole (abbreviated as mDBTBIm-II), as well as 2-[3-(di Benzothiophene-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophene-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazole-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 4,6-bis[3-(phenanthrene-9-yl)phenyl Examples include heterocyclic compounds having a diazine skeleton, such as [nyl]pyrimidine (abbreviated as 4,6mPnP2Pm) and 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviated as 4,6mDBTP2Pm-II), and heterocyclic compounds having a pyridine skeleton, such as 3,5-bis[3-(9H-carbazole-9-yl)phenyl]pyridine (abbreviated as 35DCzPPy) and 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviated as TmPyPB). Among the above, heterocyclic compounds having a diazine skeleton and heterocyclic compounds having a pyridine skeleton are preferred due to their good reliability. In particular, heterocyclic compounds having a diazine (pyrimidine or pyrazine) skeleton have high electron transport properties and contribute to reducing the driving voltage. The organic compounds described in Embodiment 1 are also materials with electron transport properties and can be used as hosts.By using the organic compound described in Embodiment 1, a layer with a low refractive index can be formed inside the EL layer 103, thereby improving the external quantum efficiency of the light-emitting device.

[0260] The TADF materials listed above can be used as host materials. When a TADF material is used as a host material, the triplet excitation energy generated by the TADF material is converted into singlet excitation energy through reverse intersystem crossing, and this energy is then transferred to the light-emitting material, thereby increasing the luminescence efficiency of the light-emitting device. In this case, the TADF material functions as an energy donor, and the light-emitting material functions as an energy acceptor.

[0261] This is particularly effective when the light-emitting material is a fluorescent material. Furthermore, in order to obtain high luminescence efficiency, it is preferable that the S1 level of the TADF material is higher than that of the fluorescent material. Also, it is preferable that the T1 level of the TADF material is higher than that of the fluorescent material. Therefore, it is preferable that the T1 level of the TADF material is higher than that of the fluorescent material.

[0262] Furthermore, it is preferable to use a TADF material that exhibits emission that overlaps with the wavelength of the lowest-energy absorption band of the fluorescent material. This is preferable because it allows for smooth transfer of excitation energy from the TADF material to the fluorescent material, resulting in efficient emission.

[0263] Furthermore, for singlet excitation energy to be efficiently generated from triplet excitation energy by reverse intersystem crossing, it is preferable that carrier recombination occurs in the TADF material. It is also preferable that the triplet excitation energy generated in the TADF material does not transfer to the triplet excitation energy of the fluorescent material. To achieve this, it is preferable that the fluorescent material has protecting groups around the luminescent phosphodiocyte (the skeleton that causes luminescence). Preferred protecting groups are substituents that do not have π bonds, and saturated hydrocarbons are preferred. Specifically, examples include alkyl groups having 3 to 10 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 10 carbon atoms, and trialkylsilyl groups having 3 to 10 carbon atoms. It is even preferable to have multiple protecting groups. Substituents that do not have π bonds have poor carrier transport function, and therefore can increase the distance between the TADF material and the luminescent phosphodiocyte of the fluorescent material with little effect on carrier transport or carrier recombination. Here, the luminescent phosphodiocyte refers to the atomic group (skeleton) that causes luminescence in the fluorescent material. The luminescent phosphodiosity preferably has a skeleton containing π bonds, preferably contains an aromatic ring, and preferably has a condensed aromatic ring or a condensed heteroaromatic ring. Examples of condensed aromatic rings or condensed heteroaromatic rings include phenanthrene skeletons, stilbene skeletons, acridone skeletons, phenoxazine skeletons, and phenothiazine skeletons. Fluorescent materials having naphthalene, anthracene, fluorene, chrysene, triphenylene, tetracene, pyrene, perylene, coumarin, quinacridone, or naphthobisbenzofuran skeletons are particularly preferred due to their high fluorescence quantum yield.

[0264] When using a fluorescent material as the light-emitting material, a material having an anthracene skeleton is preferred as the host material. Using a material having an anthracene skeleton as the host material for a fluorescent material makes it possible to realize a light-emitting layer with good luminescence efficiency and durability. Among the materials having an anthracene skeleton to be used as the host material, materials having a diphenylanthracene skeleton, and especially a 9,10-diphenylanthracene skeleton, are preferred because they are chemically stable. Furthermore, while a carbazole skeleton is preferred as the host material because it improves hole injection and transport, a benzocarbazole skeleton, in which a benzene ring is further condensed into carbazole, is even more preferred because the HOMO is about 0.1 eV shallower than carbazole, making it easier for holes to enter. In particular, a dibenzocarbazole skeleton is preferred as the HOMO is about 0.1 eV shallower than carbazole, making it easier for holes to enter, and it also has excellent hole transport properties and high heat resistance. Therefore, a more preferable host material is a substance that simultaneously possesses a 9,10-diphenylanthracene skeleton and a carbazole skeleton (or a benzocarbazole skeleton or dibenzocarbazole skeleton). Furthermore, from the viewpoint of hole injection and transport properties, a benzofluorene skeleton or a dibenzofluorene skeleton may be used instead of the carbazole skeleton. Examples of such substances include 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviated as PCzPA), 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviated as PCPN), 9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviated as CzPA), and 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole. Examples include ruvasol (abbreviated as cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl]-benzo[b]naphtho[1,2-d]furan (abbreviated as 2mBnfPPA), 9-phenyl-10-{4-(9-phenyl-9H-fluoren-9-yl)biphenyl-4'-yl}anthracene (abbreviated as FLPPA), and 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviated as αN-βNPAnth).In particular, CzPA, cgDBCzPA, 2mBnfPPA, and PCzPA exhibit very good characteristics and are therefore preferred choices.

[0265] The host material may be a mixture of multiple substances, and when using a mixed host material, it is preferable to mix an electron-transporting material with a hole-transporting material. By mixing an electron-transporting material with a hole-transporting material, the transport properties of the light-emitting layer 113 can be easily adjusted, and the recombination region can also be easily controlled. The weight ratio of the hole-transporting material to the electron-transporting material should be 1:19 to 19:1.

[0266] Furthermore, phosphorescent materials can be used as part of the above-mentioned mixed materials. When a fluorescent material is used as the light-emitting material, the phosphorescent material can be used as an energy donor to supply excitation energy to the fluorescent material.

[0267] Furthermore, these mixed materials may form an excited complex. It is preferable to select a combination that forms an excited complex that exhibits emission overlapping with the wavelength of the lowest-energy absorption band of the luminescent material, as this facilitates smooth energy transfer and efficiently obtains light emission. This configuration is also preferable because it reduces the driving voltage.

[0268] Furthermore, at least one of the materials forming the excitation complex may be a phosphorescent material. By doing so, the triplet excitation energy can be efficiently converted to singlet excitation energy through reverse intersystem crossing.

[0269] For efficient excitation complex formation, it is preferable that the HOMO level of the hole-transporting material is above the HOMO level of the electron-transporting material. Furthermore, it is preferable that the LUMO level of the hole-transporting material is above the LUMO level of the electron-transporting material. The LUMO and HOMO levels of the materials can be derived from the electrochemical properties (reduction potential and oxidation potential) of the materials measured by cyclic voltammetry (CV).

[0270] The formation of excited complexes can be confirmed, for example, by comparing the emission spectra of a hole-transporting material, an electron-transporting material, and a mixed film made by mixing these materials, and observing that the emission spectrum of the mixed film shifts to a longer wavelength than the emission spectra of each individual material (or has a new peak on the longer wavelength side). Alternatively, it can be confirmed by comparing the transient photoluminescence (PL) of a hole-transporting material, the transient PL of an electron-transporting material, and the transient PL of a mixed film made by mixing these materials, and observing differences in the transient response, such as the transient PL lifetime of the mixed film having a longer lifetime component or a larger proportion of the delayed component than the transient PL lifetime of each individual material. Furthermore, the transient PL mentioned above can be replaced with transient electroluminescence (EL). That is, the formation of excited complexes can also be confirmed by comparing the transient EL of a hole-transporting material, the transient EL of an electron-transporting material, and the transient EL of a mixed film made by mixing these materials, and observing the differences in the transient response.

[0271] The electron transport layer 114 is a layer containing a substance having electron transport properties. The electron transport layer 114 is preferably formed with a film thickness of, for example, 10 nm or more and 50 nm or less, preferably 15 nm or more and 35 nm or less. As the substance having electron transport properties, it is preferable to use the electron transport layer material or organic compound disclosed in Embodiment 1. By using the electron transport layer material or organic compound disclosed in Embodiment 1 for the electron transport layer 114, a layer with a low refractive index can be formed inside the EL layer 103, thereby improving the external quantum efficiency of the light-emitting device.

[0272] When using an electron transport layer material or organic compound other than those disclosed in Embodiment 1 for the electron transport layer 114, any of the substances listed above as having electron transport properties that can be used as the host material can be used.

[0273] The electron transport layer 114 preferably contains an electron-transporting material and an alkali metal or alkaline earth metal in elemental form, compound, or complex form. In particular, an alkali metal organometallic complex is preferred, and a lithium organometallic complex is even more preferred. The ligand of the organometallic complex is particularly preferably one having an 8-quinolinolato structure, and more preferably 8-quinolinolatolithium or 6-methyl-8-quinolinolatolithium. The electron transport layer 114 having this configuration may also serve as the electron injection layer 115.

[0274] Furthermore, the electron transport layer 114 has an electron mobility of 1 × 10⁻¹⁴ at an electric field strength [V / cm] square root of 600. -7 cm 2 / Vs or more 5×10 -5 cm 2It is preferable that the value is less than or equal to / Vs. By reducing the electron transport properties in the electron transport layer 114, the amount of electrons injected into the light-emitting layer can be controlled, and it is possible to prevent the light-emitting layer from becoming electron-excessive. This configuration is particularly preferable because it results in a good lifetime when the hole injection layer is formed as a composite material and the HOMO level of the material having hole transport properties in the composite material is a relatively deep HOMO level between -5.7eV and -5.4eV. In this case, it is preferable that the HOMO level of the material having electron transport properties is -6.0eV or higher. Furthermore, it is preferable that the material having electron transport properties is an organic compound having an anthracene skeleton, and more preferably an organic compound containing both an anthracene skeleton and a heterocyclic skeleton. The heterocyclic skeleton is preferably a nitrogen-containing five-membered ring skeleton or a nitrogen-containing six-membered ring skeleton. These heterocyclic skeletons are particularly preferably nitrogen-containing five-membered ring skeletons or nitrogen-containing six-membered ring skeletons that contain two heteroatoms in the ring, such as pyrazole rings, imidazole rings, oxazole rings, thiazole rings, pyrazine rings, pyrimidine rings, and pyridazine rings. Furthermore, the alkali metal or alkaline earth metal element, compound, or complex preferably contains an 8-hydroxyquinolinate structure. Specifically, examples include 8-hydroxyquinolinate-lithium (abbreviated as Liq) and 8-hydroxyquinolinate-sodium (abbreviated as Naq). In particular, complexes of monovalent metal ions, especially lithium complexes, are preferred, with Liq being more preferred. When an 8-hydroxyquinolinate structure is included, its methyl-substituted derivatives (e.g., 2-methyl-substituted derivatives or 5-methyl-substituted derivatives) can also be used. Furthermore, it is preferable that within the electron transport layer, there is a concentration difference (including cases where it is zero) of alkali metals or alkaline earth metals in elemental form, compound, or complex form along the thickness direction.

[0275] The electron transport layer 114 is provided between the light-emitting layer 113 and the second electrode 102. Alternatively, an electron injection layer 115 may be provided between the electron transport layer 114 and the second electrode 102, containing an alkali metal or alkaline earth metal, or a compound thereof, such as lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), or 8-hydroxyquinolinatolithium (Liq). The electron injection layer 115 may be a layer containing an alkali metal or alkaline earth metal or a compound thereof within a layer of electron-transporting material, or an electride may be used. Examples of electrides include a substance obtained by adding a high concentration of electrons to a mixed oxide of calcium and aluminum.

[0276] Furthermore, a material obtained by mixing an electron-transporting material with an alkali metal or alkaline earth metal in its elemental form, compound, or complex form may be used as the electron injection layer 115. The electron-transporting material can be any of the materials listed as suitable for use in the electron injection layer 114. Note that the electron injection layer 115 having this configuration may also serve as the electron injection layer 114.

[0277] Furthermore, as the electron injection layer 115, it is also possible to use a layer containing an electron-transporting substance (preferably an organic compound having a bipyridine skeleton) with an alkali metal or alkaline earth metal fluoride at a concentration above that which results in a microcrystalline state (50 wt% or more). Since this layer has a low refractive index, it is possible to provide a light-emitting device with better external quantum efficiency.

[0278] Alternatively, a charge generation layer 116 may be provided instead of the electron injection layer 115 (Figure 1(B)). The charge generation layer 116 is a layer that can inject holes into the layer in contact with the cathode side and electrons into the layer in contact with the anode side by applying a potential. The charge generation layer 116 includes at least a P-type layer 117. The P-type layer 117 is preferably formed using a composite material listed above as a material that can constitute the hole injection layer 111. The P-type layer 117 may also be formed by laminating a film containing the acceptor material and a film containing the hole transport material as materials that constitute the composite material. By applying a potential to the P-type layer 117, electrons are injected into the electron transport layer 114 and holes are injected into the second electrode 102, which is the cathode, and the light-emitting device operates.

[0279] Furthermore, it is preferable that the charge generation layer 116 includes, in addition to the P-type layer 117, one or both of the electron relay layer 118 and the electron injection buffer layer 119.

[0280] The electron relay layer 118 contains at least an electron-transporting material and has the function of preventing interaction between the electron injection buffer layer 119 and the P-type layer 117, thereby smoothly transferring electrons. The LUMO level of the electron-transporting material contained in the electron relay layer 118 is preferably between the LUMO level of the acceptor material in the P-type layer 117 and the LUMO level of the material contained in the layer in contact with the charge generation layer 116 in the electron transport layer 114. The specific energy level of the LUMO level of the electron-transporting material used in the electron relay layer 118 is preferably -5.0 eV or higher, more preferably -5.0 eV or higher and -3.0 eV or lower. It is preferable to use a phthalocyanine-based material or a metal complex having a metal-oxygen bond and an aromatic ligand as the electron-transporting material used in the electron relay layer 118.

[0281] The electron injection buffer layer 119 can use materials with high electron injection potential, such as alkali metals, alkaline earth metals, rare earth metals, and compounds thereof (alkali metal compounds (including oxides such as lithium oxide, halides, and carbonates such as lithium carbonate and cesium carbonate), alkaline earth metal compounds (including oxides, halides, and carbonates), or rare earth metal compounds (including oxides, halides, and carbonates)).

[0282] Furthermore, when the electron injection buffer layer 119 is formed by including an electron-transporting substance and a donor substance, the donor substance can include alkali metals, alkaline earth metals, rare earth metals, and compounds thereof (alkali metal compounds (including oxides such as lithium oxide, halides, and carbonates such as lithium carbonate and cesium carbonate), alkaline earth metal compounds (including oxides, halides, and carbonates), or rare earth metal compounds (including oxides, halides, and carbonates)), as well as organic compounds such as tetratianaphthalene (abbreviated as TTN), nickerosene, and decamethylnickerosene. The electron-transporting substance can be formed using the same materials as those used to constitute the electron transport layer 114 described above. Moreover, since the organic compound in one embodiment of the present invention is an organic compound with a low refractive index, using it in the electron injection buffer layer 119 can yield a light-emitting device with good external quantum efficiency.

[0283] As the material forming the second electrode 102, metals, alloys, electrically conductive compounds, and mixtures thereof with a small work function (specifically, 3.8 eV or less) can be used. Specific examples of such cathode materials include alkali metals such as lithium (Li) and cesium (Cs), elements belonging to Group 1 or 2 of the periodic table such as magnesium (Mg), calcium (Ca), and strontium (Sr), and alloys containing these (MgAg, AlLi), rare earth metals such as europium (Eu) and ytterbium (Yb), and alloys containing these. However, by providing an electron injection layer between the second electrode 102 and the electron transport layer, various conductive materials such as Al, Ag, ITO, silicon, or indium oxide-tin oxide containing silicon oxide can be used as the second electrode 102, regardless of the magnitude of their work functions. These conductive materials can be formed using dry methods such as vacuum deposition and sputtering, as well as inkjet and spin coating methods. Alternatively, they may be formed using wet methods such as the sol-gel method, or using a paste made of a metal material.

[0284] Furthermore, various methods can be used to form the EL layer 103, regardless of whether they are dry or wet methods. For example, vacuum deposition, gravure printing, offset printing, screen printing, inkjet printing, or spin coating may be used.

[0285] Furthermore, each electrode or layer described above may be formed using different film deposition methods.

[0286] The configuration of the layer provided between the first electrode 101 and the second electrode 102 is not limited to those described above. However, a configuration is preferred in which a light-emitting region is provided at a location away from the first electrode 101 and the second electrode 102 where holes and electrons recombine, in order to suppress quenching that occurs when the light-emitting region is in close proximity to the electrodes and the metal used in the carrier injection layer.

[0287] Furthermore, the hole transport layer and electron transport layer in contact with the light-emitting layer 113, and especially the carrier transport layer near the recombination region in the light-emitting layer 113, are preferably made of a material whose band gap is larger than that of the light-emitting material constituting the light-emitting layer or the light-emitting material contained in the light-emitting layer, in order to suppress energy transfer from excitons generated in the light-emitting layer.

[0288] Next, an embodiment of a light-emitting device (also called a stacked element or tandem element) with a configuration in which multiple light-emitting units are stacked will be described with reference to Figure 1(C). This light-emitting device has multiple light-emitting units between the anode and the cathode. Each light-emitting unit has a configuration almost identical to the EL layer 103 shown in Figure 1(A). In other words, the light-emitting device shown in Figure 1(C) is a light-emitting device with multiple light-emitting units, while the light-emitting device shown in Figure 1(A) or Figure 1(B) is a light-emitting device with one light-emitting unit.

[0289] In Figure 1(C), a first light-emitting unit 511 and a second light-emitting unit 512 are stacked between the anode 501 and the cathode 502, and a charge generation layer 513 is provided between the first light-emitting unit 511 and the second light-emitting unit 512. The anode 501 and the cathode 502 correspond to the first electrode 101 and the second electrode 102 in Figure 1(A), respectively, and the same components as described in the explanation of Figure 1(A) can be applied. Furthermore, the first light-emitting unit 511 and the second light-emitting unit 512 may have the same configuration or different configurations.

[0290] The charge generation layer 513 has the function of injecting electrons into one light-emitting unit and holes into the other light-emitting unit when a voltage is applied to the anode 501 and cathode 502. That is, in Figure 1(C), when a voltage is applied such that the potential of the anode is higher than the potential of the cathode, the charge generation layer 513 only needs to inject electrons into the first light-emitting unit 511 and holes into the second light-emitting unit 512.

[0291] The charge generation layer 513 is preferably formed with the same configuration as the charge generation layer 116 described in Figure 1(B). The composite material of organic compound and metal oxide has excellent carrier implantation and carrier transport properties, enabling low-voltage and low-current operation. If the anode side of the light-emitting unit is in contact with the charge generation layer 513, the charge generation layer 513 can also act as a hole injection layer for the light-emitting unit, so the light-emitting unit does not need to have a hole injection layer.

[0292] Furthermore, when an electron injection buffer layer 119 is provided in the charge generation layer 513, the electron injection buffer layer 119 plays the role of an electron injection layer in the anode-side light-emitting unit, so it is not necessarily required to form an electron injection layer in the anode-side light-emitting unit.

[0293] Figure 1(C) illustrates a light-emitting device having two light-emitting units, but the same principles can be applied to light-emitting devices with three or more stacked light-emitting units. As in the light-emitting device according to this embodiment, by arranging multiple light-emitting units separated between a pair of electrodes by a charge generation layer 513, high-brightness light emission can be achieved while maintaining a low current density, and a long-life element can be realized. Furthermore, a light-emitting device that can be driven at a low voltage and consumes little power can be realized.

[0294] Furthermore, by making the light-emitting colors of each light-emitting unit different, it is possible to obtain a desired color of light emission from the entire light-emitting device. For example, in a light-emitting device having two light-emitting units, it is possible to obtain a light-emitting device that emits white light as a whole by obtaining red and green light-emitting colors from the first light-emitting unit and blue light-emitting color from the second light-emitting unit.

[0295] Furthermore, each layer and electrode, such as the EL layer 103, the first light-emitting unit 511, the second light-emitting unit 512, and the charge generation layer, can be formed using methods such as vapor deposition (including vacuum deposition), droplet ejection (also known as inkjet printing), coating, and gravure printing. They may also contain low-molecular-weight materials, medium-molecular-weight materials (including oligomers and dendrimers), or polymer materials.

[0296] (Embodiment 3) This embodiment describes a light-emitting device using the light-emitting device described in Embodiment 2.

[0297] In this embodiment, a light-emitting device manufactured using the light-emitting device described in Embodiment 2 will be explained with reference to Figure 2. Figure 2(A) is a top view showing the light-emitting device, and Figure 2(B) is a cross-sectional view obtained by cutting Figure 2(A) along A and C. This light-emitting device includes a drive circuit section (source line drive circuit) 601, a pixel section 602, and a drive circuit section (gate line drive circuit) 603, all indicated by dotted lines, to control the light emission of the light-emitting device. Furthermore, 604 is a sealing substrate, and 605 is a sealing material, with the area enclosed by the sealing material 605 being a space 607.

[0298] The routing wiring 608 is for transmitting signals input to the source line drive circuit 601 and the gate line drive circuit 603, and receives video signals, clock signals, start signals, reset signals, etc. from the FPC (flexible printed circuit) 609, which serves as an external input terminal. Although only the FPC is shown in this illustration, a printed circuit board (PWB) may be attached to this FPC. In this specification, the light-emitting device includes not only the light-emitting device itself, but also the state in which the FPC or PWB is attached to it.

[0299] Next, the cross-sectional structure will be explained using Figure 2(B). A drive circuit section and a pixel section are formed on the element substrate 610, and here, the source line drive circuit 601, which is the drive circuit section, and one pixel in the pixel section 602 are shown.

[0300] The element substrate 610 may be manufactured using a substrate made of glass, quartz, organic resin, metal, alloy, semiconductor, or other materials, as well as a plastic substrate made of FRP (Fiber Reinforced Plastics), PVF (Polyvinyl Fluoride), polyester, or acrylic resin.

[0301] The structure of the transistors used in pixels and driving circuits is not particularly limited. For example, they may be inverse staggered transistors or staggered transistors. They may also be top-gate or bottom-gate transistors. The semiconductor material used for the transistors is not particularly limited; for example, silicon, germanium, silicon carbide, gallium nitride, etc., can be used. Alternatively, an oxide semiconductor containing at least one of indium, gallium, and zinc, such as an In-Ga-Zn metal oxide, may be used.

[0302] The crystallinity of the semiconductor material used in the transistor is not particularly limited; amorphous semiconductors, crystalline semiconductors (microcrystalline semiconductors, polycrystalline semiconductors, single-crystal semiconductors, or semiconductors having a crystalline region in part) may be used. Using a crystalline semiconductor is preferable because it can suppress the degradation of transistor characteristics.

[0303] Here, it is preferable to use oxide semiconductors for semiconductor devices such as transistors used in the pixels and driving circuits described above, as well as transistors used in touch sensors and the like, which will be described later. In particular, it is preferable to use oxide semiconductors with a wider bandgap than silicon. By using oxide semiconductors with a wider bandgap than silicon, the current in the off state of the transistor can be reduced.

[0304] The above oxide semiconductor preferably contains at least indium (In) or zinc (Zn). More preferably, it is an oxide semiconductor containing an oxide represented as an In-M-Zn oxide (where M is a metal such as Al, Ti, Ga, Ge, Y, Zr, Sn, La, Ce, or Hf).

[0305] In particular, it is preferable to use an oxide semiconductor film as the semiconductor layer, which has multiple crystalline portions, the c-axis of which is oriented perpendicular to the surface on which the semiconductor layer is formed or to the upper surface of the semiconductor layer, and which does not have grain boundaries between adjacent crystalline portions.

[0306] By using such materials as semiconductor layers, fluctuations in electrical properties can be suppressed, enabling the realization of highly reliable transistors.

[0307] Furthermore, due to its low off-current, the transistor having the aforementioned semiconductor layer can retain the charge stored in the capacitor via the transistor for a long period of time. By applying such transistors to pixels, it becomes possible to maintain the gradation of the image displayed in each display area while simultaneously stopping the drive circuit. As a result, electronic devices with extremely reduced power consumption can be realized.

[0308] It is preferable to provide an undercoat to stabilize the characteristics of the transistor. As the undercoat, an inorganic insulating film such as a silicon oxide film, silicon nitride film, silicon oxynitride film, or silicon nitride film can be used and fabricated as a single layer or in layers. The undercoat can be formed using sputtering, CVD (Chemical Vapor Deposition) (plasma CVD, thermal CVD, MOCVD (Metal Organic CVD), etc.), ALD (Atomic Layer Deposition), coating, printing, etc. Note that the undercoat may be omitted if not necessary.

[0309] Note that FET623 is one of the transistors formed in the drive circuit section 601. The drive circuit can be formed using various CMOS, PMOS, or NMOS circuits. In this embodiment, a driver-integrated type with the drive circuit formed on the substrate is shown, but this is not necessarily required, and the drive circuit can be formed externally instead of on the substrate.

[0310] Furthermore, although the pixel section 602 is formed by a plurality of pixels including a switching FET 611 and a current control FET 612 and a first electrode 613 electrically connected to its drain, it is not limited to this, and the pixel section may be a combination of three or more FETs and a capacitive element.

[0311] Furthermore, an insulator 614 is formed to cover the end of the first electrode 613. This can be formed by using a positive-type photosensitive acrylic resin film.

[0312] Furthermore, in order to ensure good coverage of the EL layer and the like that will be formed later, a curved surface with curvature is formed at the upper or lower end of the insulator 614. For example, when a positive-type photosensitive acrylic resin is used as the material for the insulator 614, it is preferable to have a curved surface with a radius of curvature (0.2 μm to 3 μm) only at the upper end of the insulator 614. In addition, either a negative-type photosensitive resin or a positive-type photosensitive resin can be used as the insulator 614.

[0313] An EL layer 616 and a second electrode 617 are formed on the first electrode 613, respectively. Here, it is desirable to use a material with a large work function for the first electrode 613 which functions as an anode. For example, in addition to single-layer films such as ITO film, silicon-containing indium tin oxide film, indium oxide film containing 2-20 wt% zinc oxide, titanium nitride film, chromium film, tungsten film, Zn film, and Pt film, a laminate of titanium nitride film and a film mainly composed of aluminum, or a three-layer structure of titanium nitride film, a film mainly composed of aluminum, and titanium nitride film can be used. Furthermore, a laminated structure has low resistance as wiring, good ohmic contact can be obtained, and it can function as an anode.

[0314] Furthermore, the EL layer 616 is formed by various methods such as vapor deposition using a vapor deposition mask, inkjet printing, and spin coating. The EL layer 616 includes the configuration described in Embodiment 2. Other materials constituting the EL layer 616 may be low molecular weight compounds or high molecular weight compounds (including oligomers and dendrimers).

[0315] Furthermore, it is preferable to use a material with a low work function (such as Al, Mg, Li, Ca, or alloys or compounds thereof (MgAg, MgIn, AlLi, etc.)) for the second electrode 617, which is formed on the EL layer 616 and functions as a cathode. When light generated in the EL layer 616 is transmitted through the second electrode 617, it is preferable to use a laminate of a thin metal film and a transparent conductive film (such as ITO, indium oxide containing 2-20 wt% zinc oxide, indium tin oxide containing silicon, or zinc oxide (ZnO)) as the second electrode 617.

[0316] The first electrode 613, the EL layer 616, and the second electrode 617 form a light-emitting device. This light-emitting device is the light-emitting device described in Embodiment 2. Although the pixel portion is made up of multiple light-emitting devices, the light-emitting device in this embodiment may contain a mixture of the light-emitting device described in Embodiment 2 and light-emitting devices having other configurations.

[0317] Furthermore, by bonding the sealing substrate 604 to the element substrate 610 with the sealing material 605, the light-emitting device 618 is provided in the space 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealing material 605. The space 607 is filled with a filler material, which may be an inert gas (such as nitrogen or argon) or a sealing material. A recess is formed in the sealing substrate, and a desiccant is placed therein to suppress deterioration due to the effects of moisture, which is a preferred configuration.

[0318] Furthermore, it is preferable to use epoxy resin or glass frit for the sealing material 605. It is also desirable that these materials are as impermeable to moisture and oxygen as possible. In addition to glass substrates and quartz substrates, plastic substrates made of FRP (Fiber Reinforced Plastics), PVF (Polyvinyl Fluoride), polyester, or acrylic resin can be used as the material for the sealing substrate 604.

[0319] Although not shown in Figure 2, a protective film may be provided on the second electrode. The protective film may be made of an organic resin film or an inorganic insulating film. Alternatively, the protective film may be formed to cover the exposed portion of the sealing material 605. Furthermore, the protective film can be provided to cover the surface and sides of the pair of substrates, the sealing layer, the insulating layer, and other exposed sides.

[0320] The protective film can be made of a material that is impermeable to impurities such as water. Therefore, it is possible to effectively suppress the diffusion of impurities such as water from the outside to the inside.

[0321] Materials that constitute the protective film can include oxides, nitrides, fluorides, sulfides, ternary compounds, metals, or polymers. For example, materials containing aluminum oxide, hafnium oxide, hafnium silicate, lanthanum oxide, silicon oxide, strontium titanate, tantalum oxide, titanium oxide, zinc oxide, niobium oxide, zirconium oxide, tin oxide, yttrium oxide, cerium oxide, scandium oxide, erbium oxide, vanadium oxide, or indium oxide can be used. Other materials containing aluminum nitride, hafnium nitride, silicon nitride, tantalum nitride, titanium nitride, niobium nitride, molybdenum nitride, zirconium nitride, or gallium nitride can be used. Nitrides containing titanium and aluminum, oxides containing titanium and aluminum, oxides containing aluminum and zinc, sulfides containing manganese and zinc, sulfides containing cerium and strontium, oxides containing erbium and aluminum, oxides containing yttrium and zirconium can be used.

[0322] It is preferable to form the protective film using a film deposition method that provides good step coverage. One such method is atomic layer deposition (ALD). It is preferable to use a material that can be formed using the ALD method for the protective film. By using the ALD method, it is possible to form a dense protective film with reduced defects such as cracks and pinholes, or a protective film with a uniform thickness. Furthermore, it is possible to reduce the damage inflicted on the processed workpiece when forming the protective film.

[0323] For example, by using the ALD method to form a protective film, it is possible to create a uniform, low-defect protective film on surfaces with complex uneven shapes, as well as on the top, sides, and back surfaces of touch panels.

[0324] As described above, a light-emitting device can be obtained using the light-emitting device described in Embodiment 2.

[0325] Since the light-emitting device in this embodiment uses the light-emitting device described in Embodiment 2, a light-emitting device with good characteristics can be obtained. Specifically, because the light-emitting device described in Embodiment 2 has good luminous efficiency, it is possible to make a light-emitting device with low power consumption.

[0326] Figure 3 shows an example of a light-emitting device that is made full-color by forming a light-emitting device that emits white light and providing a colored layer (color filter), etc. Figure 3(A) shows a substrate 1001, a base insulating film 1002, a gate insulating film 1003, gate electrodes 1006, 1007, 1008, a first interlayer insulating film 1020, a second interlayer insulating film 1021, a peripheral portion 1042, a pixel portion 1040, a drive circuit portion 1041, first electrodes 1024W, 1024R, 1024G, 1024B of the light-emitting device, a partition wall 1025, an EL layer 1028, a second electrode 1029 of the light-emitting device, a sealing substrate 1031, a sealing material 1032, etc.

[0327] In Figure 3(A), the colored layers (red colored layer 1034R, green colored layer 1034G, and blue colored layer 1034B) are provided on a transparent substrate 1033. A black matrix 1035 may also be provided. The transparent substrate 1033 on which the colored layers and black matrix are provided is aligned and fixed to the substrate 1001. The colored layers and black matrix 1035 are covered with an overcoat layer 1036. In Figure 3(A), there is an emissive layer that emits light to the outside without transmitting through the colored layers, and an emissive layer that emits light to the outside by transmitting through each colored layer. Light that does not transmit through the colored layers is white, and light that transmits through the colored layers is red, green, and blue, so an image can be represented with four colored pixels.

[0328] Figure 3(B) shows an example in which colored layers (red colored layer 1034R, green colored layer 1034G, and blue colored layer 1034B) are formed between the gate insulating film 1003 and the first interlayer insulating film 1020. Thus, the colored layers may also be provided between the substrate 1001 and the encapsulating substrate 1031.

[0329] Furthermore, although the light-emitting device described above is a bottom-emission type device that extracts light from the substrate 1001 on which the FET is formed, it may also be a top-emission type device that extracts light from the sealing substrate 1031. A cross-sectional view of the top-emission type light-emitting device is shown in Figure 4. In this case, the substrate 1001 can be a substrate that does not transmit light. The process is the same as for the bottom-emission type light-emitting device until the connecting electrode that connects the FET and the anode of the light-emitting device is fabricated. After that, a third interlayer insulating film 1037 is formed covering the electrode 1022. This insulating film may also play a planarization role. The third interlayer insulating film 1037 can be formed using the same material as the second interlayer insulating film, as well as other known materials.

[0330] The first electrodes 1024W, 1024R, 1024G, and 1024B of the light-emitting device are designated as anodes here, but they may also be cathodes. Furthermore, in the case of a top-emission type light-emitting device as shown in Figure 4, it is preferable that the first electrodes be reflective electrodes. The configuration of the EL layer 1028 is the same as that described as the EL layer 103 in Embodiment 2, and the element structure is such that white light emission can be obtained.

[0331] In the top emission structure shown in Figure 4, sealing can be performed with a sealing substrate 1031 having colored layers (red colored layer 1034R, green colored layer 1034G, and blue colored layer 1034B). A black matrix 1035 may be provided on the sealing substrate 1031 so as to be located between pixels. The colored layers (red colored layer 1034R, green colored layer 1034G, and blue colored layer 1034B) and the black matrix may be covered with an overcoat layer 1036. The sealing substrate 1031 should be a translucent substrate. In addition, although an example of full-color display using four colors, red, green, blue, and white, is shown here, it is not particularly limited, and full-color display may also be performed using four colors, red, yellow, green, and blue, or three colors, red, green, and blue.

[0332] In top-emission type light-emitting devices, a microcavity structure can be suitably applied. A light-emitting device having a microcavity structure is obtained by using a reflective electrode as the first electrode and a semi-transparent / semi-reflective electrode as the second electrode. There is at least an EL layer between the reflective electrode and the semi-transparent / semi-reflective electrode, and there is at least a light-emitting layer that forms a light-emitting region.

[0333] The reflective electrode has a visible light reflectance of 40% to 100%, preferably 70% to 100%, and its resistivity is 1 × 10⁻⁶. -2 The film thickness is assumed to be Ωcm or less. Furthermore, the semi-transparent / semi-reflective electrode has a visible light reflectance of 20% to 80%, preferably 40% to 70%, and its resistivity is 1 × 10⁻⁶. -2 Assume the membrane is less than Ωcm in diameter.

[0334] The light emitted from the light-emitting layer contained in the EL layer is reflected by the reflective electrode and the semi-transparent / semi-reflective electrode, causing resonance.

[0335] This light-emitting device allows for changing the optical distance between the reflective electrode and the semi-transparent / semi-reflective electrode by varying the thickness of the transparent conductive film, the aforementioned composite material, or the carrier transport material. This makes it possible to enhance light of resonant wavelengths and attenuate light of non-resonant wavelengths between the reflective electrode and the semi-transparent / semi-reflective electrode.

[0336] Furthermore, since the light reflected back by the reflective electrode (first reflected light) interferes significantly with the light that directly enters the semi-transparent / semi-reflective electrode from the light-emitting layer (first incident light), it is preferable to adjust the optical distance between the reflective electrode and the light-emitting layer to (2n-1)λ / 4 (where n is a natural number greater than or equal to 1, and λ is the wavelength of the light emission to be amplified). By adjusting this optical distance, the phases of the first reflected light and the first incident light can be aligned, and the light emission from the light-emitting layer can be further amplified.

[0337] In the above configuration, the EL layer may have a structure with multiple light-emitting layers or a structure with a single light-emitting layer. For example, it may be applied to a configuration in which multiple EL layers are provided in a single light-emitting device with a charge generation layer in between, and one or more light-emitting layers are formed in each EL layer, in combination with the tandem light-emitting device configuration described above.

[0338] By incorporating a microcavity structure, it becomes possible to enhance the emission intensity in the front direction at specific wavelengths, thereby reducing power consumption. Furthermore, in the case of a light-emitting device that displays images using four sub-pixels of red, yellow, green, and blue, in addition to the brightness enhancement effect of yellow emission, a microcavity structure tailored to the wavelength of each color can be applied to all sub-pixels, resulting in a light-emitting device with excellent characteristics.

[0339] Since the light-emitting device in this embodiment uses the light-emitting device described in Embodiment 2, a light-emitting device with good characteristics can be obtained. Specifically, because the light-emitting device described in Embodiment 2 has good luminous efficiency, it is possible to make a light-emitting device with low power consumption.

[0340] Up to this point, we have described an active matrix type light-emitting device, but from here on we will describe a passive matrix type light-emitting device. Figure 5 shows a passive matrix type light-emitting device manufactured by applying the present invention. Figure 5(A) is a perspective view showing the light-emitting device, and Figure 5(B) is a cross-sectional view obtained by cutting Figure 5(A) along the X and Y lines. In Figure 5, an EL layer 955 is provided on the substrate 951 between electrodes 952 and 956. The ends of electrodes 952 are covered with an insulating layer 953. A partition layer 954 is provided on the insulating layer 953. The side walls of the partition layer 954 have a slope such that the distance between one side wall and the other side wall narrows as it approaches the substrate surface. In other words, the cross-section of the partition layer 954 in the short-side direction is trapezoidal, with the bottom side (facing the same direction as the surface direction of the insulating layer 953 and in contact with the insulating layer 953) being shorter than the top side (facing the same direction as the surface direction of the insulating layer 953 and not in contact with the insulating layer 953). By providing the partition layer 954 in this way, it is possible to prevent malfunctions of the light-emitting device caused by static electricity, etc. Furthermore, even in a passive matrix type light-emitting device, the light-emitting device described in Embodiment 2 is used, resulting in a light-emitting device with good reliability or low power consumption.

[0341] As described above, the light-emitting device is suitable for use as a display device for representing images because it is possible to control each of the numerous minute light-emitting devices arranged in a matrix.

[0342] Furthermore, this embodiment can be freely combined with other embodiments.

[0343] (Embodiment 4) In this embodiment, an example of using the light-emitting device described in Embodiment 2 as an illumination device will be explained with reference to Figure 6. Figure 6(B) is a top view of the illumination device, and Figure 6(A) is a cross-sectional view of ef in Figure 6(B).

[0344] In this embodiment, the lighting device has a first electrode 401 formed on a translucent substrate 400 which serves as a support. The first electrode 401 corresponds to the first electrode 101 in Embodiment 2. When light is extracted from the first electrode 401 side, the first electrode 401 is formed from a translucent material.

[0345] A pad 412 for supplying voltage to the second electrode 404 is formed on the substrate 400.

[0346] An EL layer 403 is formed on the first electrode 401. The EL layer 403 corresponds to the configuration of the EL layer 103 in Embodiment 2, or a configuration combining the light-emitting units 511, 512 and the charge generation layer 513. Please refer to the relevant description for details on these configurations.

[0347] A second electrode 404 is formed by covering the EL layer 403. The second electrode 404 corresponds to the second electrode 102 in Embodiment 2. When light emission is extracted from the first electrode 401 side, the second electrode 404 is formed of a material with high reflectivity. Voltage is supplied to the second electrode 404 by connecting it to the pad 412.

[0348] As described above, the lighting device shown in this embodiment has a light-emitting device having a first electrode 401, an EL layer 403, and a second electrode 404. Since this light-emitting device is a light-emitting device with high luminous efficiency, the lighting device in this embodiment can be a lighting device with low power consumption.

[0349] The lighting device is completed by fixing and sealing the substrate 400, on which the light-emitting device having the above configuration is formed, and the sealing substrate 407 using sealing materials 405 and 406. Either sealing material 405 or 406 may be used. In addition, a desiccant can be mixed into the inner sealing material 406 (not shown in Figure 6(B)), which allows for the adsorption of moisture and leads to improved reliability.

[0350] Furthermore, by extending the pad 412 and a portion of the first electrode 401 outside the sealing materials 405 and 406, it can be used as an external input terminal. Alternatively, an IC chip 420 with a converter or the like may be placed on top of it.

[0351] As described above, the lighting device described in this embodiment uses the light-emitting device described in Embodiment 2 as the EL element, and can be a light-emitting device with low power consumption.

[0352] (Embodiment 5) This embodiment describes an example of an electronic device that includes the light-emitting device described in Embodiment 2 as part of it. The light-emitting device described in Embodiment 2 has good luminous efficiency and low power consumption. As a result, the electronic device described in this embodiment can be an electronic device having a light-emitting section with low power consumption.

[0353] Examples of electronic devices to which the above-mentioned light-emitting devices are applied include television equipment (also called televisions or television receivers), monitors for computers, digital cameras, digital video cameras, digital photo frames, mobile phones (also called mobile phones or mobile phone devices), portable game consoles, personal digital assistants, sound playback devices, and large game machines such as pachinko machines. Specific examples of these electronic devices are shown below.

[0354] Figure 7(A) shows an example of a television system. The television system has a display unit 7103 incorporated into a housing 7101. This figure also shows a configuration in which the housing 7101 is supported by a stand 7105. The display unit 7103 is capable of displaying images, and the display unit 7103 is constructed by arranging the light-emitting devices described in Embodiment 2 in a matrix.

[0355] The television system can be operated using the operation switches on the housing 7101 or a separate remote control unit 7110. The operation keys 7109 on the remote control unit 7110 allow for channel and volume control, and the image displayed on the display unit 7103 can be controlled. Alternatively, the remote control unit 7110 may be configured to include a display unit 7107 that displays information output from the remote control unit 7110.

[0356] The television system will consist of a receiver, modem, and other components. The receiver will be able to receive general television broadcasts, and by connecting to a wired or wireless communication network via the modem, it will also be possible to perform one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers, etc.) information communication.

[0357] Figure 7(B1) shows a computer, which includes a main unit 7201, a housing 7202, a display unit 7203, a keyboard 7204, an external connection port 7205, a pointing device 7206, etc. This computer is manufactured by arranging the light-emitting devices described in Embodiment 2 in a matrix and using them in the display unit 7203. The computer in Figure 7(B1) may also take the form shown in Figure 7(B2). The computer in Figure 7(B2) has a second display unit 7210 instead of the keyboard 7204 and pointing device 7206. The second display unit 7210 is a touch panel, and input can be performed by operating the input display shown on the second display unit 7210 with a finger or a dedicated pen. In addition to the input display, the second display unit 7210 can also display other images. The display unit 7203 may also be a touch panel. The two screens are connected by a hinge, which prevents problems such as scratching or damaging the screens when storing or transporting the device.

[0358] Figure 7(C) shows an example of a mobile terminal. The mobile phone includes a display unit 7402 built into the housing 7401, as well as operation buttons 7403, an external connection port 7404, a speaker 7405, a microphone 7406, and the like. The mobile phone has a display unit 7402 made by arranging the light-emitting devices described in Embodiment 2 in a matrix.

[0359] The mobile terminal shown in Figure 7(C) can also be configured to allow information to be entered by touching the display unit 7402 with a finger or other object. In this case, operations such as making a phone call or composing an email can be performed by touching the display unit 7402 with a finger or other object.

[0360] The display unit 7402 has three main modes. The first is a display mode that primarily displays images, the second is an input mode that primarily inputs information such as text, and the third is a display + input mode that combines the display mode and the input mode.

[0361] For example, when making a phone call or composing an email, the display unit 7402 should be set to a text input mode, which primarily focuses on text input, and the user should perform the text input operation displayed on the screen. In this case, it is preferable to display a keyboard or number buttons on most of the screen of the display unit 7402.

[0362] Furthermore, by providing a detection device with a tilt sensor such as a gyroscope or accelerometer inside the mobile terminal, the orientation of the mobile terminal (portrait or landscape) can be determined, and the screen display of the display unit 7402 can be automatically switched accordingly.

[0363] Furthermore, the screen mode can be switched by touching the display unit 7402 or by operating the operation button 7403 on the housing 7401. It is also possible to switch modes depending on the type of image displayed on the display unit 7402. For example, if the image signal displayed on the display unit is video data, it can be switched to display mode; if it is text data, it can be switched to input mode.

[0364] Furthermore, in input mode, the system may detect a signal detected by the optical sensor of the display unit 7402 and, if there is no input via touch operation on the display unit 7402 for a certain period of time, control may be made to switch the screen mode from input mode to display mode.

[0365] The display unit 7402 can also function as an image sensor. For example, by touching the display unit 7402 with the palm or fingers, palm prints, fingerprints, etc., can be captured to perform user authentication. Furthermore, by using a backlight that emits near-infrared light or a sensing light source that emits near-infrared light in the display unit, it is also possible to capture images of finger veins, palm veins, etc.

[0366] Furthermore, the configuration shown in this embodiment can be used by appropriately combining the configurations shown in Embodiments 1 to 4.

[0367] As described above, the application range of the light-emitting device equipped with the light-emitting device described in Embodiment 2 is extremely broad, and this light-emitting device can be applied to electronic devices in all fields. By using the light-emitting device described in Embodiment 2, it is possible to obtain electronic devices with low power consumption.

[0368] Figure 8(A) is a schematic diagram showing an example of a cleaning robot.

[0369] The cleaning robot 5100 has a display 5101 on its top surface, multiple cameras 5102 on its sides, a brush 5103, and control buttons 5104. Although not shown in the illustration, the cleaning robot 5100 also has wheels, a suction port, etc. on its underside. The cleaning robot 5100 is also equipped with various sensors, including an infrared sensor, an ultrasonic sensor, an accelerometer, a piezoelectric sensor, a light sensor, and a gyroscope. Furthermore, the cleaning robot 5100 is equipped with a means of wireless communication.

[0370] The cleaning robot 5100 is self-propelled, can detect dirt 5120, and can suck up the dirt through a suction port located on its underside.

[0371] Furthermore, the cleaning robot 5100 can analyze images captured by the camera 5102 to determine the presence or absence of obstacles such as walls, furniture, or steps. If the image analysis detects objects that could become entangled in the brush 5103, such as wiring, it can stop the brush 5103 from rotating.

[0372] The display 5101 can display information such as the remaining battery level and the amount of dirt collected. The path taken by the cleaning robot 5100 may also be displayed on the display 5101. Alternatively, the display 5101 may be a touch panel, and operation buttons 5104 may be provided on the display 5101.

[0373] The cleaning robot 5100 can communicate with a portable electronic device 5140, such as a smartphone. Images captured by the camera 5102 can be displayed on the portable electronic device 5140. Therefore, the owner of the cleaning robot 5100 can check the status of the room even when they are away from home. In addition, the display on the display 5101 can be checked on a portable electronic device such as a smartphone.

[0374] A light-emitting device according to one aspect of the present invention can be used in a display 5101.

[0375] The robot 2100 shown in Figure 8(B) includes a computing unit 2110, an illuminance sensor 2101, a microphone 2102, an upper camera 2103, a speaker 2104, a display 2105, a lower camera 2106, an obstacle sensor 2107, and a movement mechanism 2108.

[0376] The microphone 2102 has the function of detecting the user's voice and ambient sounds. The speaker 2104 has the function of emitting sound. The robot 2100 can communicate with the user using the microphone 2102 and speaker 2104.

[0377] The display 2105 has the function of displaying various types of information. The robot 2100 can display the information desired by the user on the display 2105. The display 2105 may be equipped with a touch panel. The display 2105 may also be a detachable information terminal, and by installing it in a fixed position on the robot 2100, charging and data transfer can be made possible.

[0378] The upper camera 2103 and the lower camera 2106 have the function of imaging the area around the robot 2100. In addition, the obstacle sensor 2107 can detect the presence or absence of obstacles in the direction of travel when the robot 2100 moves forward using the movement mechanism 2108. The robot 2100 can recognize its surrounding environment and move safely using the upper camera 2103, the lower camera 2106 and the obstacle sensor 2107. The light-emitting device according to one aspect of the present invention can be used in the display 2105.

[0379] Figure 8(C) shows an example of a goggle-type display. The goggle-type display includes, for example, a housing 5000, a display unit 5001, a speaker 5003, an LED lamp 5004, a connection terminal 5006, a sensor 5007 (including functions for measuring force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared radiation), a microphone 5008, a second display unit 5002, a support unit 5012, an earphone 5013, etc.

[0380] A light-emitting device according to one aspect of the present invention can be used in a display unit 5001 and a second display unit 5002.

[0381] Figure 9 shows an example in which the light-emitting device described in Embodiment 2 is used in a desk lamp, which is a lighting device. The desk lamp shown in Figure 9 has a housing 2001 and a light source 2002, and the lighting device described in Embodiment 3 may be used as the light source 2002.

[0382] Figure 10 shows an example of using the light-emitting device described in Embodiment 2 as an indoor lighting device 3001. Since the light-emitting device described in Embodiment 2 is a light-emitting device with high luminous efficiency, it can be used as a lighting device with low power consumption. Furthermore, since the light-emitting device described in Embodiment 2 can be made to cover a large area, it can be used as a large-area lighting device. In addition, since the light-emitting device described in Embodiment 2 is thin, it can be used as a thin lighting device.

[0383] The light-emitting device described in Embodiment 2 can also be mounted on the windshield or dashboard of an automobile. Figure 11 shows one embodiment in which the light-emitting device described in Embodiment 2 is used on the windshield or dashboard of an automobile. Display areas 5200 to 5203 are displays provided using the light-emitting device described in Embodiment 2.

[0384] Display area 5200 and display area 5201 are display devices equipped with the light-emitting device described in Embodiment 2, which is installed on the windshield of an automobile. The light-emitting device described in Embodiment 2 can be made into a so-called see-through display device, where the opposite side is visible, by making the first electrode and the second electrode from translucent electrodes. If the display is in a see-through state, it can be installed on the windshield of an automobile without obstructing the view. When providing transistors for driving, it is preferable to use translucent transistors such as organic transistors made of organic semiconductor materials or transistors made of oxide semiconductors.

[0385] The display area 5202 is a display device equipped with the light-emitting device described in Embodiment 2, which is provided on the pillar. By displaying images from an imaging means provided on the vehicle body on the display area 5202, the field of view obstructed by the pillar can be compensated for. Similarly, the display area 5203 provided on the dashboard can compensate for the field of view obstructed by the vehicle body by displaying images from an imaging means provided on the outside of the vehicle, thereby compensating for blind spots and enhancing safety. By displaying images in a way that compensates for the parts that are not visible, safety checks can be performed more naturally and without discomfort.

[0386] Display area 5203 can also provide various information by displaying navigation information, speedometer, tachometer, air conditioning settings, etc. The display items and layout can be changed as needed to suit the user's preferences. This information can also be provided in display areas 5200 to 5202. Furthermore, display areas 5200 to 5203 can also be used as lighting devices.

[0387] Figures 12(A) and (B) also show a foldable portable information terminal 5150. The foldable portable information terminal 5150 has a housing 5151, a display area 5152, and a bending section 5153. Figure 12(A) shows the portable information terminal 5150 in its unfolded state. Figure 12(B) shows the portable information terminal in its folded state. Despite having a large display area 5152, the portable information terminal 5150 is compact and highly portable when folded.

[0388] The display area 5152 can be folded in half by the bending portion 5153. The bending portion 5153 is composed of an expandable member and multiple support members, and when folded, the expandable member extends. The bending portion 5153 is folded to have a radius of curvature of 2 mm or more, preferably 3 mm or more.

[0389] The display area 5152 may also be a touch panel (input / output device) equipped with a touch sensor (input device). A light-emitting device according to one aspect of the present invention can be used in the display area 5152.

[0390] Figures 13(A) to 13(C) also show the foldable portable information terminal 9310. Figure 13(A) shows the portable information terminal 9310 in its unfolded state. Figure 13(B) shows the portable information terminal 9310 in an intermediate state, either unfolded or folded. Figure 13(C) shows the portable information terminal 9310 in its folded state. The portable information terminal 9310 offers excellent portability in its folded state and excellent readability of the display due to its seamless, wide display area in its unfolded state.

[0391] The display panel 9311 is supported by three housings 9315 connected by a hinge 9313. The display panel 9311 may also be a touch panel (input / output device) equipped with a touch sensor (input device). Furthermore, the display panel 9311 can be reversibly transformed from an unfolded state to a folded state by bending the two housings 9315 via the hinge 9313. A light-emitting device according to one aspect of the present invention can be used in the display panel 9311. [Examples]

[0392] <<Synthesis Example 1>> In this example, we will describe the synthesis method of the organic compound 2-{(3',5'-di-tert-butyl)-1,1'-biphenyl-3-yl}-4,6-bis(3,5-di-tert-butylphenyl)-1,3,5-triazine (abbreviation: mmtBumBP-dmmtBuPTzn), which was shown as structural formula (100) in Embodiment 1. The structural formula of mmtBumBP-dmmtBuPTzn is shown below.

[0393] [ka]

[0394] <Step 1: Synthesis of 3-bromo-3',5'-di-tert-butylbiphenyl> 1.0 g (4.3 mmol) of 3,5-di-t-butylphenylboronic acid, 1.5 g (5.2 mmol) of 1-bromo-3-iodobenzene, 4.5 mL of 2 mol / L potassium carbonate aqueous solution, 20 mL of toluene, and 3 mL of ethanol were added to a three-necked flask and the mixture was degassed by stirring under reduced pressure. 52 mg (0.17 mmol) of tris(2-methylphenyl)phosphine and 10 mg (0.043 mmol) of palladium(II) acetate were then added, and the mixture was reacted under a nitrogen atmosphere at 80°C for 14 hours. After the reaction was complete, the mixture was extracted with toluene, and the resulting organic layer was dried over magnesium sulfate. The mixture was filtered naturally, and the resulting filtrate was purified by silica gel column chromatography (eluent: hexane) to obtain 1.0 g of the target white solid (yield: 68%). The synthesis scheme for Step 1 is shown in formula (a-1) below.

[0395] [ka]

[0396] <Step 2: Synthesis of 2-(3',5'-di-tert-butylbiphenyl-3-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane> 1.0 g (2.9 mmol) of 3-bromo-3',5'-di-tert-butylbiphenyl, 0.96 g (3.8 mmol) of bis(pinacolate)diborone, 0.94 g (9.6 mmol) of potassium acetate, and 30 mL of 1,4-dioxane were added to a three-necked flask and the mixture was degassed by stirring under reduced pressure. Then, 0.12 g (0.30 mmol) of 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl and 0.12 g (0.15 mmol) of [1,1'-bis(diphenylphosphino)ferrocene]palladium(II) dichloride dichloromethane adduct were added, and the mixture was reacted under a nitrogen atmosphere at 110°C for 24 hours. After the reaction was complete, extraction with toluene was performed, and the resulting organic layer was dried over magnesium sulfate. The mixture was then filtered naturally. The obtained filtrate was purified by silica gel column chromatography (eluent: toluene) to obtain 0.89 g of the target yellow oil (yield: 78%). The synthesis scheme for Step 2 is shown in formula (a-2) below.

[0397] [ka]

[0398] <Step 3: Synthesis of mmtBumBP-dmmtBuPTzn> 0.8 g (1.6 mmol) of 4,6-bis(3,5-di-tert-butylphenyl)-2-chloro-1,3,5-triazine, 0.89 g (2.3 mmol) of 2-(3',5'-di-tert-butylbiphenyl-3-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane, 0.68 g (3.2 mmol) of tripotassium phosphate, 3 mL of water, 8 mL of toluene, and 3 mL of 1,4-dioxane were added to a three-necked flask and the mixture was degassed by stirring under reduced pressure. Then, 3.5 mg (0.016 mmol) of palladium(II) acetate and 10 mg (0.032 mmol) of tris(2-methylphenyl)phosphine were added, and the mixture was heated under a nitrogen atmosphere under reflux for 12 hours. After the reaction was complete, the mixture was extracted with ethyl acetate, and the resulting organic layer was dried over magnesium sulfate. The mixture was then filtered by gravity. The obtained filtrate was concentrated and purified by silica gel column chromatography (eluent ethyl acetate:hexane = 1:20) to obtain a solid. This solid was purified by silica gel column chromatography (eluent chloroform:hexane = changed from 5:1 to 1:0). The obtained solid was recrystallized with hexane to obtain 0.88 g of the target white solid (yield: 76%). The synthesis scheme for step 3 is shown in formula (a-3) below.

[0399] [ka]

[0400] The obtained white solid (0.87 g) was purified by sublimation using the train sublimation method under conditions of 230°C and 5.8 Pa while flowing argon gas. After sublimation purification, 0.82 g of the target white solid was obtained with a recovery rate of 95%.

[0401] Furthermore, nuclear magnetic resonance spectroscopy of the white solid obtained in step 3 above ( 1 The results of the analysis by 1H-NMR are shown below. From these results, it was found that in this example, the organic compound mmtBumBP-dmmtBuPTzn, which is one embodiment of the present invention represented by the above-mentioned structural formula (100), was obtained.

[0402] H 1 NMR (CDCl3,300MHz): δ=1.42-1.49(m,54H),7.50(s,1H),7.61-7.70(m,5H),7.87(d,1H),8.68-8.69(m,4H),8.78(d,1H),9.06(s,1H).

[0403] Furthermore, the absorption spectrum of mmtBumBP-dmmtBuPTzn was measured using a UV-Vis spectrophotometer (JASCO Corporation, V550 model). The absorption spectrum of mmtBumBP-dmmtBuPTzn was obtained by subtracting the spectrum measured with only dichloromethane placed in a quartz cell from the absorption spectrum of a dichloromethane solution. As a result, an absorption peak was observed at 267 nm, and it was found that there was no absorption in the visible region, from 440 nm to 700 nm.

[0404] Next, the mmtBumBP-dmmtBuPTzn obtained in this example was analyzed by liquid chromatography mass spectrometry (LC / MS analysis).

[0405] LC / MS analysis was performed using a Thermo Fisher Scientific Ultimate 3000 for LC (liquid chromatography) separation, followed by MS (mass spectrometry) analysis using a Thermo Fisher Scientific Q Exactive.

[0406] For LC separation, any column was used with a column temperature of 40°C, and the solvent was appropriately selected for the delivery conditions. The sample was prepared by dissolving mmtBumBP-dmmtBuPTzn of any concentration in an organic solvent, and the injection volume was 5.0 μL.

[0407] MS / MS measurements were performed on the exact mass of mmtBumBP-dmmtBuPTzn at m / z 721.53 using the PRM method. The PRM settings were configured with a target ion mass range of m / z 721.53 ± 2.0 (isolation window = 4), and detection was performed in positive mode. The NCE (Normalized Collision Energy) for accelerating the target ion in the collision cell was set to 50. The MS spectrum obtained from the MS / MS measurement is shown in Figure 14.

[0408] Fragment ions with m / z values ​​of 216.17 and 292.21 were detected. These are thought to be fragments composed of one substituent bonded to triazine and carbon and nitrogen atoms derived from triazine. For example, m / z 216.17 is thought to be a fragment in which one carbon and one nitrogen atom derived from triazine are bonded to a phenyl group to which two tertiary butyl groups are bonded. Similarly, m / z 292.21 is thought to be a fragment in which one carbon and one nitrogen atom derived from triazine are bonded to a biphenyl group to which two tertiary butyl groups are bonded. These fragments can be considered a characteristic feature of compounds with a triazine skeleton.

[0409] Next, the glass transition temperature was investigated using a differential scanning calorimetry (DSC, PerkinElmer, Pyris 1 DSC). From the measurement results, the glass transition temperature was found to be 112°C. Thus, it was found that the organic compound according to one embodiment of the present invention exhibits a high glass transition temperature and has good heat resistance.

[0410] Figure 15 shows the results of measuring the refractive index of mmtBumBP-dmmtBuPTzn using a spectroscopic ellipsometer (M-2000U, J.A. Woo-Lam Japan). For the measurement, a film was used in which each layer material was deposited on a quartz substrate by vacuum deposition, with a thickness of approximately 50 nm. The figure also shows the refractive index of the ordinary ray (n,Ordinary) and the refractive index of the extraordinary ray (n,Extra-ordinary).

[0411] From this figure, it can be seen that mmtBumBP-dmmtBuPTzn has a paraphotonic refractive index in the range of 1.50 to 1.75 throughout the entire blue emission region (455 nm to 465 nm), and also has a paraphotonic refractive index in the range of 1.45 to 1.70 at 633 nm, indicating that it is a material with a low refractive index.

[0412] Furthermore, good luminescence was obtained from light-emitting devices fabricated using this organic compound as an electron transport material. [Examples]

[0413] ≪Synthesis Example 2≫ In this example, we will describe the synthesis method of the organic compound 2-{(3',5'-di-tert-butyl)-1,1'-biphenyl-3-yl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mmtBumBPTzn), which was shown as structural formula (120) in Embodiment 1. The structure of mmtBumBPTzn is shown below.

[0414] [ka]

[0415] <Step 1: Synthesis of 3-bromo-3',5'-di-tert-butylbiphenyl> The synthesis was performed in the same manner as in step 1 of synthesis example 1.

[0416] <Step 2: Synthesis of 2-(3',5'-di-tert-butylbiphenyl-3-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane> The synthesis was performed in the same manner as in step 2 of synthesis example 1.

[0417] <Step 3: Synthesis of mmtBumBPTzn> In a three-necked flask, 1.5 g (5.6 mmol) of 4,6-diphenyl-2-chloro-1,3,5-triazine, 2.4 g (6.2 mmol) of 2-(3',5'-di-tert-butylbiphenyl-3-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane, 2.4 g (11 mmol) of tripotassium phosphate, 10 mL of water, 28 mL of toluene, and 10 mL of 1,4-dioxane were added, and the mixture was degassed by stirring under reduced pressure. Then, 13 mg (0.056 mmol) of palladium(II) acetate and 34 mg (0.11 mmol) of tris(2-methylphenyl)phosphine were added, and the mixture was heated under reflux under a nitrogen atmosphere for 14 hours to allow the reaction to proceed. After the reaction was complete, extraction was performed with ethyl acetate, and the water in the resulting organic layer was removed with magnesium sulfate. The mixture was filtered naturally, and the resulting filtrate was purified by silica gel column chromatography (with the developing solvent chloroform:hexane = changed from 1:5 to 1:3). The filtrate was then recrystallized with hexane to obtain 2.0 g of the desired white solid (yield: 51%). The synthesis scheme for step 3 is shown in formula (b-1) below.

[0418] [ka]

[0419] 2.0 g of the obtained white solid was purified by sublimation using the train sublimation method under argon gas flow, pressure of 3.4 Pa, and temperature of 220°C. The solid was then heated. After sublimation purification, 1.8 g of the target white solid was obtained with a recovery rate of 80%.

[0420] Furthermore, nuclear magnetic resonance spectroscopy of the white solid obtained in step 3 above ( 1 The results of the analysis by 1H-NMR are shown below. From these results, it was found that in this example, an organic compound, mmtBumBPTzn, which is one embodiment of the present invention represented by the above-mentioned structural formula (120), was obtained.

[0421] H 1NMR (CDCl3, 300MHz): δ = 1.44 (s, 18H), 7.51-7.68 (m, 10H), 7.83 (d, 1H), 8.73-8.81 (m, 5H), 9.01 (s, 1H).

[0422] Next, the absorption spectrum of mmtBumBPTzn was measured using a UV-Vis spectrophotometer (JASCO Corporation, V550 model). The absorption spectrum of mmtBumBPTzn was obtained by subtracting the spectrum measured with only dichloromethane in a quartz cell from the absorption spectrum of a dichloromethane solution. As a result, an absorption peak was observed at 271 nm in the dichloromethane solution of mmtBumBPTzn. Since there was no absorption in the visible region, from 440 nm to 700 nm, it was found to have good absorption properties as a display material.

[0423] Next, the mmtBumBPTzn obtained in this example was analyzed by liquid chromatography-mass spectrometry (LC / MS analysis).

[0424] LC / MS analysis was performed using a Thermo Fisher Scientific Ultimate 3000 for LC (liquid chromatography) separation, followed by MS (mass spectrometry) analysis using a Thermo Fisher Scientific Q Exactive.

[0425] For LC separation, any column was used with a column temperature of 40°C, and the solvent was appropriately selected for the delivery conditions. The sample was prepared by dissolving mmtBumBPTzn of any concentration in an organic solvent, and the injection volume was 5.0 μL.

[0426] MS / MS measurements were performed on the exact mass of mmtBumBPTzn at m / z 497.28 using the PRM method. The PRM settings were configured with a target ion mass range of m / z 497.28 ± 2.0 (isolation window = 4), and detection was performed in positive mode. The NCE (Normalized Collision Energy) for accelerating the target ion in the collision cell was set to 50. The MS spectra obtained from the MS / MS measurements are shown in Figure 16.

[0427] Fragment ions with m / z values ​​of 104.05 and 292.21 were detected. These are thought to be fragments composed of one substituent bonded to triazine and carbon and nitrogen atoms derived from triazine. For example, m / z 104.05 is thought to be a fragment in which one carbon and one nitrogen atom derived from triazine are bonded to a phenyl group. m / z 292.21 is thought to be a fragment in which one carbon and one nitrogen atom derived from triazine are bonded to a substituent other than the phenyl group. These fragments can be said to be a characteristic feature of compounds with a triazine skeleton.

[0428] Figure 17 shows the results of measuring the refractive index of mmtBumBPTzn using a spectroscopic ellipsometer (M-2000U, J.A. Woo-Lam Japan). For the measurement, a film was used in which each layer material was deposited on a quartz substrate by vacuum deposition, with a thickness of approximately 50 nm. The figure also shows the refractive index of the ordinary ray (n,Ordinary) and the refractive index of the extraordinary ray (n,Extra-ordinary).

[0429] From this figure, it can be seen that mmtBumBPTzn has a paraphotonic refractive index in the range of 1.50 to 1.75 throughout the entire blue emission region (455 nm to 465 nm), and also has a paraphotonic refractive index in the range of 1.45 to 1.70 at 633 nm, indicating that it is a material with a low refractive index.

[0430] Furthermore, good luminescence was obtained from light-emitting devices fabricated using this organic compound as an electron transport material. [Examples]

[0431] ≪Synthesis Example 3≫ In this example, we will describe the synthesis method of the organic compound shown as structural formula (121) in Embodiment 1, 2-(3,3'',5,5''-tetra-tert-butyl-1,1':3',1''-terphenyl-5'-yl)-4,6-diphenyl-1,3,5-triazine (abbreviation: mmtBumTPTzn). The structure of mmtBumTPTzn is shown below.

[0432] [ka]

[0433] <Step 1: Synthesis of mmtBumTPTzn> 0.67 g (2.5 mmol) of 4,6-diphenyl-2-chloro-1,3,5-triazine, 1.6 g (2.8 mmol) of 2-3,5-bis(3,5-di-tert-butylphenyl)benzene-1-yl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane, 1.1 g (5.0 mmol) of tripotassium phosphate, 5 mL of water, 14 mL of toluene, and 5 mL of 1,4-dioxane were added to a three-necked flask and the mixture was degassed by stirring under reduced pressure. 5.6 mg (0.025 mmol) of palladium(II) acetate and 15 mg (0.050 mmol) of tris(2-methylphenyl)phosphine were then added, and the mixture was heated under a nitrogen atmosphere under reflux for 19 hours. After the reaction was complete, the reaction solution was filtered and separated into filtrate and filtrate (1). The obtained filtrate was extracted with ethyl acetate, and the resulting organic layer was dried over magnesium sulfate. This mixture was filtered, the resulting filtrate was concentrated and filtered to obtain filtrate (2).

[0434] The obtained filtrates (1) and (2) were combined and purified by silica gel column chromatography (eluent chloroform:hexane = 1:5), and then recrystallized in toluene to obtain 1.2 g of the target white solid (yield: 71%). The synthesis scheme of Step 1 is shown in formula (c-1) below.

[0435] [ka]

[0436] The obtained white solid (1.2 g) was purified by sublimation using the train sublimation method under an argon gas stream at a pressure of 3.4 Pa and 285°C. After sublimation purification, 1.1 g of the target white solid was obtained with a recovery rate of 89%.

[0437] Furthermore, nuclear magnetic resonance spectroscopy of the white solid obtained in step 1 above ( 1 The results of the analysis by 1H-NMR are shown below. From these results, it was found that in this example, an organic compound, mmtBumTPTzn, which is one embodiment of the present invention represented by the above-mentioned structural formula (121), was obtained.

[0438] H 1 NMR (CDCl3, 300MHz): δ = 1.44 (s, 36H), 7.54-7.62 (m, 12H), 7.99 (t, 1H), 8.79 (d, 4H), 8.92 (d, 2H).

[0439] Next, the absorption spectrum of mmtBumTPTzn was measured using a UV-Vis spectrophotometer (JASCO Corporation, V550 model). The absorption spectrum of mmtBumTPTzn was obtained by subtracting the spectrum measured with only dichloromethane in a quartz cell from the absorption spectrum of a dichloromethane solution. As a result, an absorption peak was observed at 265 nm, and it was found that there was no absorption in the visible region, from 440 nm to 700 nm.

[0440] Next, the mmtBumTPTzn obtained in this example was analyzed by liquid chromatography-mass spectrometry (LC / MS analysis).

[0441] LC / MS analysis was performed using a Thermo Fisher Scientific Ultimate 3000 for LC (liquid chromatography) separation, followed by MS (mass spectrometry) analysis using a Thermo Fisher Scientific Q Exactive.

[0442] For LC separation, any column was used with a column temperature of 40°C, and the solvent was appropriately selected for the delivery conditions. The sample was prepared by dissolving mmtBumTPTzn of any concentration in an organic solvent, and the injection volume was 5.0 μL.

[0443] MS / MS measurements were performed on the exact mass of mmtBumTPTzn at m / z 685.44 using the PRM method. The PRM settings were configured with a target ion mass range of m / z 685.44 ± 2.0 (isolation window = 4), and detection was performed in positive mode. The NCE (Normalized Collision Energy) for accelerating the target ion in the collision cell was set to 50. The MS spectra obtained from the MS / MS measurements are shown in Figure 18.

[0444] Fragment ions with m / z values ​​of 104.05 and 480.36 were detected. These are thought to be fragments composed of one substituent bonded to triazine and carbon and nitrogen atoms derived from triazine. For example, m / z 104.05 is thought to be a fragment in which one carbon and one nitrogen atom derived from triazine are bonded to a phenyl group. m / z 480.36 is thought to be a fragment in which one carbon and one nitrogen atom derived from triazine are bonded to a substituent other than the phenyl group. These fragments can be said to be a characteristic feature of compounds with a triazine skeleton.

[0445] Figure 19 shows the results of measuring the refractive index of mmtBumTPTzn using a spectroscopic ellipsometer (M-2000U, J.A. Woo-Lam Japan). For the measurement, a film was used in which each layer material was deposited on a quartz substrate by vacuum deposition, with a thickness of approximately 50 nm. The figure shows the refractive index of the ordinary ray (n,Ordinary) and the refractive index of the extraordinary ray (n,Extra-ordinary).

[0446] From this figure, it can be seen that mmtBumTPTzn has a paraphotonic refractive index in the range of 1.50 to 1.75 throughout the entire blue emission region (455 nm to 465 nm), and also has a paraphotonic refractive index in the range of 1.45 to 1.70 at 633 nm, indicating that it is a material with a low refractive index.

[0447] Furthermore, good luminescence was obtained from light-emitting devices fabricated using this organic compound as an electron transport material. [Examples]

[0448] <<Synthesis Example 4>> In this example, we will describe the synthesis method of the organic compound 2-(3',5'-di-tert-butylbiphenyl-3-yl)-4,6-bis(3,5-di-tert-butylphenyl)pyrimidine (abbreviation: mmtBumBP-dmmtBuPPm), which was shown as structural formula (200) in Embodiment 1. The structure of mmtBumBP-dmmtBuPPm is shown below.

[0449] [ka]

[0450] <Step 1: Synthesis of 4,6-bis(3,5-di-tert-butylphenyl)-2-chloro-1,3-pyrimidine> 1.4 g (7.8 mmol) of 2,4,6-trichloropyrimidine, 40 mL of acetonitrile, 16 mL of water, 3.8 g (16 mmol) of 3,5-di-tert-butylphenylboronic acid, and 4.3 g (31 mmol) of potassium carbonate were added to a three-necked flask and the mixture was degassed by stirring under reduced pressure. 0.22 g (0.31 mmol) of bis(triphenylphosphine)palladium(II) dichloride was added, and the mixture was stirred at 50°C for 4 hours under a nitrogen atmosphere. After the reaction was complete, toluene was added to the reaction mixture, and it was washed with water and saturated brine. The water in the resulting organic layer was removed with magnesium sulfate. The mixture was then filtered by gravity. The resulting filtrate was concentrated and purified by silica gel column chromatography (eluent hexane:toluene = 1:1) to obtain 2.7 g of the target product as a white solid in 71% yield. The synthesis scheme for Step 1 is shown in formula (d-1) below.

[0451] [ka]

[0452] <Step 2: Synthesis of 3-bromo-3',5'-di-tert-butylbiphenyl> The synthesis was performed in the same manner as in step 1 of synthesis example 1.

[0453] <Step 3: Synthesis of 2-(3',5'-di-tert-butylbiphenyl-3-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane> The synthesis was performed in the same manner as in step 2 of synthesis example 1.

[0454] <Step 4: Synthesis of mmtBumBP-dmmtBuPPm> In a three-necked flask, 0.93 g (1.9 mmol) of 4,6-bis(3,5-di-tert-butylphenyl)-2-chloro-1,3-pyrimidine synthesized in Step 1, 0.92 g (2.3 mmol) of 2-(3',5'-di-tert-butylbiphenyl-3-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane synthesized in Step 3, 0.53 g (3.8 mmol) of potassium carbonate, 20 mL of tetrahydrofuran (THF), and 4 mL of water were added, and the mixture was degassed by stirring under reduced pressure. 17 mg (0.057 mmol) of tri-tert-butylphosphonium tetrafluoroborate and 17 mg (0.019 mmol) of tris(dibenzylideneacetone)dipalladium(0) were added, and the solution was stirred at 80°C under a nitrogen atmosphere for 17 hours. After the reaction was complete, toluene was added to the reaction mixture, washed with water and saturated brine, and the water in the resulting organic layer was removed with magnesium sulfate. This mixture was filtered by gravity. The resulting filtrate was purified by silica gel column chromatography (eluent hexane:toluene = 4:1) to obtain approximately 1.3 g of the target product as a white solid (yield approximately 95%). The synthesis scheme for step 4 is shown in formula (d-2) below.

[0455] [ka]

[0456] Furthermore, nuclear magnetic resonance spectroscopy of the white solid obtained in step 4 above ( 1 The results of the analysis by 1H-NMR are shown below. From these results, it was found that in this example, the organic compound mmtBumBP-dmmtBuPPm, which is one embodiment of the present invention represented by the above-mentioned structural formula (200), was obtained.

[0457] H 1 NMR (CDCl3,300MHz): δ=1.39-1.45(m,54H),7.47(t,1H),7.59-7.65(m,5H),7.76(d,1H),7.95(s,1H),8.06(d,4H),8.73(d,1H),8.99(s,1H).

[0458] Next, the absorption spectrum of mmtBumBP-dmmtBuPPm was measured using a UV-Vis spectrophotometer (JASCO Corporation, V550 model). The absorption spectrum of mmtBumBP-dmmtBuPPm was obtained by subtracting the spectrum measured with only dichloromethane in a quartz cell from the absorption spectrum of a dichloromethane solution. As a result, an absorption peak was observed at 267 nm, and it was found that there was no absorption in the visible region, from 440 nm to 700 nm.

[0459] Next, the mmtBumBP-dmmtBuPPm obtained in this example was analyzed by liquid chromatography mass spectrometry (LC / MS analysis).

[0460] LC / MS analysis was performed using a Thermo Fisher Scientific Ultimate 3000 for LC (liquid chromatography) separation, followed by MS (mass spectrometry) analysis using a Thermo Fisher Scientific Q Exactive.

[0461] For LC separation, any column was used with a column temperature of 40°C, and the solvent was appropriately selected for the delivery conditions. The sample was prepared by dissolving mmtBumBP-dmmtBuPPm at any concentration in an organic solvent, and the injection volume was 5.0 μL.

[0462] MS / MS measurements were performed using the PRM method at the exact mass of mmtBumBP-dmmtBuPPm, with a m / z of 720.54. The PRM settings were configured with a target ion mass range of m / z 720.54 ± 2.0 (isolation window = 4), and detection was performed in positive mode. The NCE (Normalized Collision Energy) for accelerating the target ions within the collision cell was set to 70. The MS spectra obtained from the MS / MS measurements are shown in Figure 20.

[0463] A fragment ion with m / z 216.17 was detected. This is thought to be a fragment composed of one of the substituents attached to the triazine and carbon and nitrogen atoms derived from the triazine. For example, m / z 216.17 is thought to be a fragment in which one carbon and one nitrogen atom derived from the pyrimidine are attached to a phenyl group. This fragment can be said to be a characteristic feature of compounds with a pyrimidine skeleton.

[0464] Figure 21 shows the results of measuring the refractive index of mmtBumBP-dmmtBuPPm using a spectroscopic ellipsometer (M-2000U, J.A. Woo-Lam Japan). For the measurement, a film was used in which each layer material was deposited on a quartz substrate by vacuum deposition, with a thickness of approximately 50 nm. The figure also shows the refractive index of the ordinary ray (n,Ordinary) and the refractive index of the extraordinary ray (n,Extra-ordinary).

[0465] From this figure, it can be seen that mmtBumBP-dmmtBuPPm has a paraphotonic refractive index in the range of 1.50 to 1.75 throughout the entire blue emission region (455 nm to 465 nm), and also has a paraphotonic refractive index in the range of 1.45 to 1.70 at 633 nm, indicating that it is a material with a low refractive index.

[0466] Furthermore, good luminescence was obtained from light-emitting devices fabricated using this organic compound as an electron transport material. [Examples]

[0467] In this embodiment, a light-emitting device 1 and a comparative light-emitting device 1 according to one embodiment of the present invention described in the embodiments will be explained. The structural formulas of the organic compounds used in this embodiment are shown below.

[0468] [ka]

[0469] (Method for fabricating light-emitting device 1) First, a reflective electrode made of an alloy film of silver (Ag), palladium (Pd), and copper (Cu) (Ag-Pd-Cu(APC) film) was deposited on a glass substrate by sputtering to a thickness of 100 nm. Then, a transparent electrode made of indium tin oxide (ITSO) containing silicon oxide was deposited by sputtering to a thickness of 85 nm to form the first electrode 101. The electrode area was 4 mm². 2 (2mm x 2mm)

[0470] Next, as a pretreatment for forming a light-emitting device on the substrate, the substrate surface was washed with water, baked at 200°C for 1 hour, and then subjected to UV ozone treatment for 370 seconds.

[0471] Then, 10 -4 The substrate was introduced into a vacuum deposition apparatus where the internal pressure was reduced to approximately Pa. After vacuum firing at 170°C for 30 minutes in the heating chamber of the vacuum deposition apparatus, the substrate was allowed to cool for about 30 minutes.

[0472] Next, the substrate on which the first electrode 101 is formed is fixed to a substrate holder provided in a vacuum deposition apparatus so that the surface on which the first electrode 101 is formed faces downwards. Then, a hole injection layer 111 is formed on the first electrode 101 by co-depositing N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviated as PCBBiF) represented by the above structural formula (i) and an electron acceptor material (OCHD-001) at a weight ratio of 1:0.05 (=PCBBiF:OCHD-001) to a thickness of 10 nm using a vapor deposition method.

[0473] After depositing PCBBiF at a thickness of 20 nm onto the hole injection layer 111, N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviated as DBfBB1TP), represented by the above structural formula (ii), was deposited at a thickness of 10 nm to form a hole transport layer 112.

[0474] Next, an electron blocking layer was formed on the hole transport layer 112 by depositing 3,3'-(naphthalene-1,4-diyl)bis(9-phenyl-9H-carbazole) (abbreviated as PCzN2), represented by structural formula (iii), to a thickness of 10 nm.

[0475] Subsequently, 2-(10-phenyl-9-anthracenyl)-benzo[b]naphtho[2,3-d]furan (abbreviated as Bnf(II)PhA), represented by structural formula (iv), and 3,10-bis[N-(9-phenyl-9H-carbazole-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviated as 3,10PCA2Nbf(IV)-02), represented by structural formula (v), were co-deposited at a weight ratio of 1:0.015 (=Bnf(II)PhA:3,10PCA2Nbf(IV)-02) at a density of 25 nm to form the light-emitting layer 113.

[0476] Next, a hole blocking layer was formed by depositing a low refractive index material, 2-{(3',5'-di-tert-butyl)-1,1'-biphenyl-3-yl}-4,6-bis(3,5-di-tert-butylphenyl)-1,3,5-triazine (abbreviated as mmtBumBP-dmmtBuPTzn) (structural formula (100)), which is one embodiment of the present invention as described in Example 1, to a thickness of 10 nm. Then, an electron transport layer 114 was formed by co-depositing mmtBumBP-dmmtBuPTzn and 6-methyl-8-quinolinolato-lithium (abbreviated as Li-6mq), represented by structural formula (vii), to a thickness of 20 nm in a weight ratio of 1:1 (=mmtBumBP-dmmtBuPTzn:Li-6mq).

[0477] After forming the electron transport layer 114, an electron injection layer 115 was formed by depositing Li-6mq to a thickness of 1 nm. Finally, the second electrode 102 was formed by co-depositing silver (Ag) and magnesium (Mg) in a volume ratio of 1:0.1 and a film thickness of 15 nm to fabricate the light-emitting device 1. The second electrode 102 is a semi-transmissive / semi-reflective electrode having both light-reflecting and light-transmitting functions, and the light-emitting device in this embodiment is a top-emission type element that extracts light from the second electrode 102. In addition, 1,3,5-tri(dibenzothiophen-4-yl)-benzene (abbreviated as DBT3P-II), represented by structural formula (x), was deposited on the second electrode 102 to a thickness of 70 nm to improve extraction efficiency.

[0478] (Method for fabricating comparative light-emitting device 1) Comparative light-emitting device 1 has a hole transport layer 112 thickness of 15 nm, and instead of mmtBumBP-dmmtBuPTzn used in the hole block layer, it uses 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)-1,1'-biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mFBPTzn), represented by structural formula (vi), and mmtBumBP-dmmtBu used in the electron transport layer 114 The device was fabricated in the same manner as light-emitting device 1, using 2-[3-(2,6-dimethyl-3-pyridinyl)-5-(9-phenantrenyl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviated as mPn-mDMePyPTzn), represented by the above structural formula (viii), instead of PTzn, and using 8-quinolinolato-lithium (abbreviated as Liq), represented by structural formula (ix), instead of Li-6mq used in the electron transport layer 114 and electron injection layer 115.

[0479] The element structures of light-emitting device 1 and comparative light-emitting device 1 are summarized in Table 1 below.

[0480] [Table 1]

[0481] Furthermore, the refractive indices of mmtBumBP-dmmtBuPTzn, mPn-mDMePyPTzn, Li-6mq, and Liq are shown in Figure 22, respectively, and their refractive indices at 456 nm are shown in Table 2. The refractive indices were measured using a spectroscopic ellipsometer (M-2000U, J.A. Woolam Japan). For the measurement samples, films were used in which each layer material was deposited on a quartz substrate by vacuum deposition to a thickness of approximately 50 nm. Note that the figures show the refractive index of the ordinary ray (n,Ordinary) and the refractive index of the extraordinary ray (n,Extra-ordinary).

[0482] [Table 2]

[0483] Each of the above-mentioned light-emitting devices was sealed with a glass substrate in a glove box under a nitrogen atmosphere to prevent exposure to the atmosphere (sealant was applied around the element, UV treatment was performed during sealing, and heat treatment was performed at 80°C for 1 hour). After this, the initial characteristics of these light-emitting devices were measured. No special measures were taken to improve the removal efficiency of the sealed glass substrate.

[0484] Figure 23 shows the luminance-current density characteristics of light-emitting device 1 and comparative light-emitting device 1, Figure 24 shows the current efficiency-luminance characteristics, Figure 25 shows the luminance-voltage characteristics, Figure 26 shows the current-voltage characteristics, Figure 27 shows the blue index-luminance characteristics, and Figure 28 shows the emission spectra of light-emitting device 1 and comparative light-emitting device 1. 2 Table 3 shows the main characteristics of the vicinity. Luminance, CIE chromaticity, and emission spectrum were measured using a spectroradiometer (Topcon SR-UL1R) at room temperature.

[0485] The Blue Index (BI) is a value obtained by dividing the current efficiency (cd / A) by the y-chromaticity, and is one of the indicators that represent the emission characteristics of blue light. Blue light tends to have higher color purity as the y-chromaticity decreases. High-purity blue light can express a wide range of blue colors even with a small luminance component, and by using high-purity blue light, the required luminance to express blue decreases, resulting in a reduction in power consumption. Therefore, BI, which takes into account y-chromaticity as one of the indicators of blue purity, is suitably used as a means of representing the efficiency of blue light, and it can be said that light-emitting devices with a high BI are more efficient as blue light-emitting devices used in displays.

[0486] [Table 3]

[0487] As shown in Figures 23 to 28 and Table 3, the results indicate that the light-emitting device 1 using a low refractive index material, which is one embodiment of the present invention, exhibits almost the same emission spectrum as the comparative light-emitting device 1, while being an EL device with better current efficiency than the comparative light-emitting device 1.

[0488] Furthermore, the light-emitting device 1 and the comparative light-emitting device 1 have a luminescence of 1000 cd / m². 2 The blue index (BI) values ​​in the vicinity were 153 (cd / A / y) and 148 (cd / A / y), respectively, and the maximum BI values ​​were 161 (cd / A / y) and 149 (cd / A / y), respectively. Thus, the light-emitting device 1 can be said to be a light-emitting device with particularly good BI. For this reason, one aspect of the present invention is suitable for a light-emitting device used in a display. [Examples]

[0489] In this embodiment, a light-emitting device 2 and a comparative light-emitting device 2, which are aspects of the present invention, will be described. The structural formulas of the organic compounds used in this embodiment are shown below.

[0490] [ka]

[0491] (Method for fabricating light-emitting device 2) First, a reflective electrode made of an alloy film of silver (Ag), palladium (Pd), and copper (Cu) (Ag-Pd-Cu(APC) film) was deposited on a glass substrate by sputtering to a thickness of 100 nm. Then, a transparent electrode made of indium tin oxide (ITSO) containing silicon oxide was deposited by sputtering to a thickness of 85 nm to form the first electrode 101. The electrode area was 4 mm². 2 (2mm x 2mm)

[0492] Next, as a pretreatment for forming a light-emitting device on the substrate, the substrate surface was washed with water, baked at 200°C for 1 hour, and then subjected to UV ozone treatment for 370 seconds.

[0493] Then, 10 -4 The substrate was introduced into a vacuum deposition apparatus where the internal pressure was reduced to approximately Pa. After vacuum firing at 170°C for 30 minutes in the heating chamber of the vacuum deposition apparatus, the substrate was allowed to cool for about 30 minutes.

[0494] Next, the substrate on which the first electrode 101 is formed is fixed to a substrate holder provided in a vacuum deposition apparatus so that the surface on which the first electrode 101 is formed faces downwards. Then, a hole injection layer 111 is formed on the first electrode 101 by co-depositing N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviated as PCBBiF) represented by the above structural formula (i) and an electron acceptor material (OCHD-001) at a weight ratio of 1:0.05 (=PCBBiF:OCHD-001) to a thickness of 10 nm using a vapor deposition method.

[0495] After depositing PCBBiF at a thickness of 20 nm onto the hole injection layer 111, N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviated as DBfBB1TP), represented by the above structural formula (ii), was deposited at a thickness of 10 nm to form a hole transport layer 112.

[0496] Next, an electron blocking layer was formed on the hole transport layer 112 by depositing 3,3'-(naphthalene-1,4-diyl)bis(9-phenyl-9H-carbazole) (abbreviated as PCzN2), represented by the above structural formula (iii), to a thickness of 10 nm.

[0497] Subsequently, 2-(10-phenyl-9-anthracenyl)-benzo[b]naphtho[2,3-d]furan (abbreviated as Bnf(II)PhA), represented by the above structural formula (iv), and 3,10-bis[N-(9-phenyl-9H-carbazole-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviated as 3,10PCA2Nbf(IV)-02), represented by the above structural formula (v), were co-deposited at a weight ratio of 1:0.015 (=Bnf(II)PhA:3,10PCA2Nbf(IV)-02) at a density of 25 nm to form an emissive layer 113.

[0498] Next, a hole-blocking layer was formed by depositing a low refractive index material, 2-{(3',5'-di-tert-butyl)-1,1'-biphenyl-3-yl}-4,6-diphenyl-1,3,5-triazine (abbreviated as mmtBumBPTzn) (structural formula (120)), which is one embodiment of the present invention as described in Example 2, to a thickness of 10 nm. Then, an electron transport layer 114 was formed by co-depositing mmtBumBPTzn and 8-quinolinolato-lithium (abbreviated as Liq), represented by the above structural formula (ix), to a thickness of 1:1 (=mmtBumBPTzn:Liq) to a thickness of 20 nm.

[0499] After forming the electron transport layer 114, an electron injection layer 115 was formed by depositing Liq to a thickness of 1 nm. Finally, the second electrode 102 was formed by co-depositing silver (Ag) and magnesium (Mg) in a volume ratio of 1:0.1 and a film thickness of 15 nm to fabricate the light-emitting device 2. The second electrode 102 is a semi-transmissive / semi-reflective electrode having both light-reflecting and light-transmitting functions, and the light-emitting device in this embodiment is a top-emission type element that extracts light from the second electrode 102. In addition, 1,3,5-tri(dibenzothiophen-4-yl)-benzene (abbreviated as DBT3P-II), represented by the above structural formula (x), was deposited on the second electrode 102 to a thickness of 70 nm to improve extraction efficiency.

[0500] (Method for fabricating comparative light-emitting device 2) Comparative light-emitting device 2 was fabricated in the same manner as light-emitting device 2, except that the film thickness of the hole transport layer 112 was changed to 15 nm, the mmtBumBPTzn used in the hole blocking layer was changed to 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)-1,1'-biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviated as mFBPTzn) represented by the above structural formula (vi), and the mmtBumBPTzn used in the electron transport layer 114 was changed to 2-[3-(2,6-dimethyl-3-pyridinyl)-5-(9-phenantrenyl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviated as mPn-mDMePyPTzn) represented by the above structural formula (viii).

[0501] The element structures of light-emitting device 2 and comparative light-emitting device 2 are summarized in Table 4 below.

[0502] [Table 4]

[0503] Furthermore, the refractive indices of mmtBumBPTzn and mPn-mDMePyPTzn are shown in Figure 29, and the refractive indices at 456 nm are shown in Table 5. Measurements were performed using a spectroscopic ellipsometer (M-2000U, J.A. Woolam Japan). For the measurement samples, films were used in which each layer material was deposited on a quartz substrate by vacuum deposition to a thickness of approximately 50 nm. Note that the figures show the refractive index of the ordinary ray (n,Ordinary) and the refractive index of the extraordinary ray (n,Extra-ordinary).

[0504] [Table 5]

[0505] The above-mentioned light-emitting devices and comparative light-emitting devices were sealed with a glass substrate in a glove box under a nitrogen atmosphere to prevent exposure to the atmosphere (sealing material was applied around the elements, UV treatment was performed during sealing, and heat treatment was performed at 80°C for 1 hour). After this, the initial characteristics of these light-emitting devices were measured. No special measures were taken to improve the removal efficiency of the sealed glass substrate.

[0506] Figure 30 shows the luminance-current density characteristics of light-emitting device 2 and comparative light-emitting device 2, Figure 31 shows the current efficiency-luminance characteristics, Figure 32 shows the luminance-voltage characteristics, Figure 33 shows the current-voltage characteristics, Figure 34 shows the blue index-luminance characteristics, and Figure 35 shows the emission spectra. Furthermore, the luminance values ​​of light-emitting device 2 and comparative light-emitting device 2 at 1000 cd / m² are also shown. 2 Table 6 shows the main characteristics of the vicinity. Luminance, CIE chromaticity, and emission spectrum were measured using a spectroradiometer (Topcon SR-UL1R) at room temperature.

[0507] [Table 6]

[0508] Figures 30 to 35 and Table 6 show that the light-emitting device 2 using a low refractive index material according to one embodiment of the present invention exhibits almost the same emission spectrum as the comparative light-emitting device 2, while being an EL device with better current efficiency than the comparative light-emitting device 2.

[0509] Furthermore, the maximum BI values ​​for light-emitting device 2 and comparative light-emitting device 2 were 159 (cd / A / y) and 144 (cd / A / y), respectively. Thus, light-emitting device 2 can be said to be a light-emitting device with particularly good BI. For this reason, one aspect of the present invention is suitable for light-emitting devices used in displays. [Examples]

[0510] ≪Synthesis Example 5≫ In this example, we will describe the synthesis method of the organic compound shown as structural formula (123) in Embodiment 1, 2-(3,3'',5',5''-tetra-tert-butyl-1,1':3',1''-terphenyl-5-yl)-4,6-diphenyl-1,3,5-triazine (abbreviation: mmtBumTPTzn-02). The structure of mmtBumTPTzn-02 is shown below.

[0511] [ka]

[0512] <Step 1: Synthesis of 3,3'',5',5''-tetra-t-butyl-1,1':3',1''-terphenyl-5-yl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane> 1.0 g (1.9 mmol) of 5-bromo-3,3'',5',5''-tetra-t-butyl-1,1':3',1''-terphenyl, 0.62 g (2.4 mmol) of bis(pinacolate)diborone, 0.61 g (6.2 mmol) of potassium acetate, and 18 mL of 1,4-dioxane were added to a three-necked flask and degassed. 0.077 g (0.094 mmol) of [1,1'-bis(diphenylphosphino)ferrocene]palladium(II) dichloride dichloromethane adduct was added, and the mixture was reacted at 110°C under a nitrogen stream for 24 hours.

[0513] After the reaction was complete, extraction with toluene was performed, and the resulting organic layer was dried over magnesium sulfate. This mixture was filtered naturally, and the resulting filtrate was concentrated. This was purified by silica gel column chromatography, changing the developing solvent from toluene:hexane = 2:1 to toluene only, to obtain 0.78 g of the target white solid (yield: 72%). The synthesis scheme for Step 1 is shown in the following formula (e-1).

[0514] [ka]

[0515] <Step 2: Synthesis of mmtBumTPTzn-02> 0.33 g (1.2 mmol) of 4,6-diphenyl-2-chloro-1,3,5-triazine, 0.78 g (1.3 mmol) of 3,3'',5',5''-tetra-t-butyl-1,1':3',1''-terphenyl-5-yl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane, 0.57 g (2.7 mmol) of tripotassium phosphate, 3 mL of water, 7 mL of toluene, and 3 mL of 1,4-dioxane were added to a three-necked flask and degassed. Then, 3 mg (0.013 mmol) of palladium(II) acetate and 8 mg (0.027 mmol) of tris(2-methylphenyl)phosphine were added, and the mixture was heated under a nitrogen atmosphere for 20 hours under reflux. After the reaction was complete, extraction with toluene was performed, and the resulting organic layer was dried over magnesium sulfate. The mixture was filtered naturally, and the filtrate was concentrated to obtain a yellow solid. This solid was purified by silica gel column chromatography using chloroform:hexane in a ratio of 5:1 to 3:1, yielding 0.70 g of a white solid. This solid was recrystallized in ethanol / hexane to obtain 0.64 g of the desired white solid (yield: 76%). The synthesis scheme for Step 2 is shown in formula (e-2) below.

[0516] [ka]

[0517] Furthermore, nuclear magnetic resonance spectroscopy of the white solid obtained in step 2 above ( 1 The results of the analysis by 1H-NMR are shown below. From these results, it was found that in this example, the organic compound mmtBumTPTzn-02, which is one embodiment of the present invention represented by the above-mentioned structural formula (123), was obtained.

[0518] H 1 NMR(CDCl3,300MHz):δ=1.41(s,18H),1.49(s,9H),1.52(s,9H),7.49(s,3 H),7.58-7.63(m,7H),7.69-7.70(m,2H),7.88(t,1H),8.77-8.83(m,6H).

[0519] Next, the absorption spectrum of mmtBumTPTzn-02 was measured using a UV-Vis spectrophotometer (JASCO Corporation, V550 model). The absorption spectrum of mmtBumTPTzn-02 was obtained by subtracting the spectrum measured with only dichloromethane in a quartz cell from the absorption spectrum of a dichloromethane solution. As a result, an absorption peak was observed at 267 nm, and it was found that there was no absorption in the visible region, from 440 nm to 700 nm.

[0520] Next, the mmtBumTPTzn-02 obtained in this example was analyzed by liquid chromatography-mass spectrometry (LC / MS analysis).

[0521] LC / MS analysis was performed using a Thermo Fisher Scientific Ultimate 3000 for LC (liquid chromatography) separation, followed by MS (mass spectrometry) analysis using a Thermo Fisher Scientific Q Exactive.

[0522] For LC separation, any column was used with a column temperature of 40°C, and the solvent was appropriately selected for the delivery conditions. The sample was prepared by dissolving mmtBumTPTzn-02 at any concentration in an organic solvent, and the injection volume was 5.0 μL.

[0523] MS / MS measurements were performed on the Exact Mass of mmtBumTPTzn-02 at m / z 685.44 using the PRM method. The PRM settings were configured with a target ion mass range of m / z 685.44 ± 2.0 (isolation window = 4), and detection was performed in positive mode. The NCE (Normalized Collision Energy) for accelerating the target ion in the collision cell was set to 50. The MS spectrum obtained from the MS / MS measurement is shown in Figure 52.

[0524] Fragment ions with m / z values ​​of 104.05 and 670.42 were detected. These are thought to be fragments composed of one substituent bonded to triazine and carbon and nitrogen atoms derived from triazine. For example, m / z 104.05 is thought to be a fragment in which one carbon and one nitrogen atom derived from triazine are bonded to a phenyl group. m / z 670.42 is thought to be a fragment in which one carbon and one nitrogen atom derived from triazine are bonded to a substituent other than the phenyl group. These fragments can be said to be a characteristic feature of compounds with a triazine skeleton.

[0525] Figure 53 shows the results of measuring the refractive index of mmtBumTPTzn-02 using a spectroscopic ellipsometer (M-2000U, manufactured by J.A. Woolam Japan). For the measurement, a film was used in which each layer of material was deposited on a quartz substrate by vacuum deposition, with a thickness of approximately 50 nm. The figure shows the refractive index of the ordinary ray (n,Ordinary) and the refractive index of the extraordinary ray (n,Extra-ordinary).

[0526] From this figure, it can be seen that mmtBumTPTzn-02 has a paraphoton refractive index of 1.65 throughout the entire blue emission region (455 nm to 465 nm), which is in the range of 1.50 to 1.75. Furthermore, its paraphoton refractive index at 633 nm is 1.61, which is in the range of 1.45 to 1.70, indicating that it is a material with a low refractive index.

[0527] Furthermore, good luminescence was obtained from light-emitting devices fabricated using this organic compound as an electron transport material. [Examples]

[0528] In this embodiment, light-emitting devices 3, 4, and 5, which are aspects of the present invention, will be described. The structural formulas of the organic compounds used in this embodiment are shown below.

[0529] [ka]

[0530] (Methods for fabricating each light-emitting device) First, a first electrode 101 was formed on a glass substrate by sputtering indium tin oxide (ITSO) containing silicon oxide as a transparent electrode, with a film thickness of 110 nm. The electrode area was 4 mm². 2 (2mm x 2mm)

[0531] Next, as a pretreatment for forming a light-emitting device on the substrate, the substrate surface was washed with water, baked at 200°C for 1 hour, and then subjected to UV ozone treatment for 370 seconds.

[0532] Then, 10 -4 The substrate was introduced into a vacuum deposition apparatus where the internal pressure was reduced to approximately Pa. After vacuum firing at 170°C for 30 minutes in the heating chamber of the vacuum deposition apparatus, the substrate was allowed to cool for about 30 minutes.

[0533] Next, the substrate on which the first electrode 101 is formed is fixed to a substrate holder provided in a vacuum deposition apparatus so that the surface on which the first electrode 101 is formed faces downwards. Then, a hole injection layer 111 is formed on the first electrode 101 by co-depositing N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviated as PCBBiF) represented by the above structural formula (i) and an electron acceptor material (OCHD-001) at a weight ratio of 1:0.05 (=PCBBiF:OCHD-001) to a thickness of 10 nm using a vapor deposition method.

[0534] After depositing PCBBiF at a thickness of 80 nm onto the hole injection layer 111, N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviated as DBfBB1TP), represented by the above structural formula (ii), was deposited at a thickness of 10 nm to form a hole transport layer 112.

[0535] Next, an electron blocking layer was formed on the hole transport layer 112 by depositing 3,3'-(naphthalene-1,4-diyl)bis(9-phenyl-9H-carbazole) (abbreviated as PCzN2), represented by structural formula (iii), to a thickness of 10 nm.

[0536] Subsequently, 2-(10-phenyl-9-anthracenyl)-benzo[b]naphtho[2,3-d]furan (abbreviated as Bnf(II)PhA), represented by structural formula (iv), and 3,10-bis[N-(9-phenyl-9H-carbazole-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviated as 3,10PCA2Nbf(IV)-02), represented by structural formula (v), were co-deposited at a weight ratio of 1:0.015 (=Bnf(II)PhA:3,10PCA2Nbf(IV)-02) at a density of 25 nm to form the light-emitting layer 113.

[0537] Next, in light-emitting devices 3 and 4, a low refractive index material, 2-{(3',5'-di-tert-butyl)-1,1'-biphenyl-3-yl}-4,6-bis(3,5-di-tert-butylphenyl)-1,3,5-triazine (abbreviated as mmtBumBP-dmmtBuPTzn) (structural formula (100)), which is one embodiment of the present invention as described in Example 1, is deposited to a thickness of 10 nm to form a hole-blocking layer. Then, in the case of light-emitting device 3, mmtBumBP-dmmtBuPTzn is expressed as structural formula (ix). In the case of light-emitting device 4, 8-quinolinolato-lithium (abbreviated as Liq) was co-deposited at a weight ratio of 1:1 (=mmtBumBP-dmmtBuPTzn:Liq) at a density of 20 nm to form the electron transport layer 114. In the case of light-emitting device 4, mmtBumBP-dmmtBuPTzn and 6-methyl-8-quinolinolato-lithium (abbreviated as Li-6mq), represented by structural formula (vii), were co-deposited at a weight ratio of 1:1 (=mmtBumBP-dmmtBuPTzn:Li-6mq) at a density of 20 nm to form the electron transport layer 114. After forming the electron transport layer 114, in the case of light-emitting device 3, Liq was deposited at a density of 1 nm to form the electron injection layer 115, and in the case of light-emitting device 4, Li-6mq was deposited at a density of 1 nm to form the electron injection layer 115.

[0538] Furthermore, in the light-emitting device 5, a hole-blocking layer was formed by depositing a low refractive index material, 2-{(3',5'-di-tert-butyl)-1,1'-biphenyl-3-yl}-4,6-diphenyl-1,3,5-triazine (abbreviated as mmtBumBPTzn) (structural formula (120)), which is one embodiment of the present invention as described in Example 2, to a thickness of 10 nm. Then, an electron transport layer 114 was formed by co-depositing mmtBumBPTzn and 8-quinolinolato-lithium (abbreviated as Liq), represented by structural formula (ix), to a thickness of 1:1 (=mmtBumBPTzn:Liq) to a thickness of 20 nm. After forming the electron transport layer 114, an electron injection layer 115 was formed by depositing Liq to a thickness of 1 nm.

[0539] Finally, aluminum was deposited to a thickness of 200 nm to form the second electrode 102, and each light-emitting device was fabricated. The second electrode 102 is a reflective electrode that has the function of reflecting light, and the light-emitting device in this embodiment is a bottom-emission type element that extracts light from the first electrode 101.

[0540] The element structures of light-emitting devices 3, 4, and 5 are summarized in Table 7 below.

[0541] [Table 7]

[0542] Table 8 shows the refractive indices at 456 nm for mmtBumBP-dmmtBuPTzn, mmtBumBPTzn, Li-6mq, and Liq. The refractive index was measured using a spectroscopic ellipsometer (M-2000U, J.A. Woolam Japan). For the measurement samples, films were used in which each layer material was deposited on a quartz substrate by vacuum deposition to a thickness of approximately 50 nm.

[0543] [Table 8]

[0544] Each of the above-mentioned light-emitting devices was sealed with a glass substrate in a glove box under a nitrogen atmosphere to prevent exposure to the atmosphere (sealant was applied around the element, UV treatment was performed during sealing, and heat treatment was performed at 80°C for 1 hour). After this, the initial characteristics of these light-emitting devices were measured. No special measures were taken to improve the removal efficiency of the sealed glass substrate.

[0545] Figure 36 shows the luminance-current density characteristics of light-emitting devices 3, 4, and 5, Figure 37 shows the current efficiency-luminance characteristics, Figure 38 shows the luminance-voltage characteristics, Figure 39 shows the current density-voltage characteristics, Figure 40 shows the power efficiency-luminance characteristics, Figure 41 shows the emission spectrum, and Figure 42 shows the external quantum efficiency-luminance characteristics. Furthermore, the luminance characteristics of light-emitting devices 3, 4, and 5 at 1000 cd / m² are also shown. 2 Table 9 shows the main characteristics in the vicinity. A spectroradiometer (Topcon SR-UL1R) was used to measure luminance, CIE chromaticity, and emission spectrum at room temperature. The external quantum efficiency was calculated using the luminance and emission spectrum measured with the spectroradiometer, assuming a Lambertsian optical distribution pattern.

[0546] [Table 9]

[0547] As shown in Figures 36 to 42 and Table 9, the light-emitting devices 3, 4, and 5, which use a low refractive index material according to one embodiment of the present invention, are EL devices with good current efficiency and external luminescence efficiency.

[0548] Next, reliability tests were performed on each light-emitting device. The results of the reliability tests for light-emitting devices 3, 4, and 5 are shown in Figure 43. In these reliability figures, the vertical axis represents the normalized brightness (%) with the initial brightness set to 100%, and the horizontal axis represents the device's operating time (h). For the reliability tests, each light-emitting device was tested at 50 mA / cm². 2A drive test was conducted at a constant current density.

[0549] From the above results, it was shown that the low refractive index material mmtBumBP-dmmtBuPTzn, which is one aspect of the present invention, and the light-emitting devices 3, 4, and 5 shown in this embodiment, which use mmtBumBPTzn in the EL layer, all exhibited a normalized brightness of approximately 80% or more after 200 hours, demonstrating that they are highly reliable light-emitting devices. [Examples]

[0550] ≪Synthesis Example 6≫ In this example, we will describe the synthesis method of the organic compound 2-{3-(3,5-dicyclohexylphenyl)phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated as mmchmBPTzn), which was shown as structural formula (412) in Embodiment 1. The structure of mmchmBPTzn is shown below.

[0551] [ka]

[0552] <Step 1: Synthesis of mmchmBPTzn> 2.7 g (6.1 mmol) of 2,4-diphenyl-6-[3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]-1,3,5-triazine, 1.7 g (4.3 mmol) of 3,5-dicyclohexyl-1-phenyltrifluoromethanesulfonate, and 1.7 g (12 mmol) of potassium carbonate were placed in a three-necked flask. 60 ml of toluene, 12 ml of ethanol, and 6 ml of water were added to this mixture, and the mixture was stirred under reduced pressure to degass it. Then, 0.25 g (0.61 mmol) of 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (SPhos) and 0.0275 g (0.123 mmol) of palladium(II) acetate were added to this mixture, and the mixture was stirred at 80°C for 9.5 hours under a nitrogen atmosphere.

[0553] After the reaction was complete, the reaction solution was filtered and extracted with ethyl acetate. The extract was filtered through Celite, dehydrated with magnesium sulfate, and concentrated to obtain a brown solid containing the target product. The obtained solid was purified by silica gel column chromatography using a developing solvent whose polarity was changed from chloroform:hexane=1:5 to chloroform:hexane=1:3 to obtain the target white solid. The synthesis scheme for Step 1 is shown below.

[0554] [ka]

[0555] The obtained solid was further purified by high-performance liquid column chromatography. High-performance liquid column chromatography was performed using chloroform as the developing solvent. The resulting fraction was concentrated to obtain the target oil. The obtained oil was recrystallized with hexane / toluene to obtain the target white solid in a yield of 1.5 g and 65%.

[0556] The obtained white solid (1.5 g) was purified by sublimation using the train sublimation method. The conditions were heating the solid at 265°C for 19 hours under a pressure of 6.5 Pa while flowing argon gas. After sublimation purification, 1.1 g of the target white solid was obtained with a recovery rate of 73%.

[0557] Furthermore, the molecular weight of the target product obtained by the above synthesis method was measured using a GC / MS detector (Thermo Fisher ITQ1100 ion trap type GCMS system). This detected a peak mainly associated with mass number 549 (mode EI+). From these results, it was found that in this example, the organic compound mmchmBPTzn, which is one embodiment of the present invention represented by the above-mentioned structural formula (412), was obtained.

[0558] Next, the absorption spectrum of mmchmBPTzn was measured using a UV-Vis spectrophotometer (JASCO Corporation, V550 model). The absorption spectrum of mmchmBPTzn was obtained by subtracting the spectrum measured with only dichloromethane in a quartz cell from the absorption spectrum of a dichloromethane solution. As a result, an absorption peak was observed at 271 nm, and it was found that there was no absorption in the visible region, from 440 nm to 700 nm.

[0559] Next, the mmchmBPTzn obtained in this example was subjected to LC / MS analysis.

[0560] LC / MS analysis was performed using a Thermo Fisher Scientific Ultimate3000 for LC separation, followed by MS analysis (mass spectrometry) using a Thermo Fisher Scientific Q Exactive.

[0561] For LC separation, any column was used with a column temperature of 40°C, and the solvent was appropriately selected for the delivery conditions. The sample was prepared by dissolving mmchmBPTZn of any concentration in an organic solvent, and the injection volume was 5.0 μL.

[0562] MS / MS measurements were performed on the exact mass of mmchmBPTzn at m / z 549.31 using the PRM method. The PRM settings were configured with a target ion mass range of m / z 549.31 ± 2.0 (isolation window = 4), and detection was performed in positive mode. The NCE (Numerical Cervical Energy) for accelerating the target ion in the collision cell was set to 50. The MS spectra obtained from the MS / MS measurements are shown in Figure 58.

[0563] Fragment ions with m / z values ​​of 104.05 and 344.24 were detected. These are thought to be fragments composed of one substituent bonded to triazine and carbon and nitrogen atoms derived from triazine. For example, m / z 104.05 is thought to be a fragment in which one carbon and one nitrogen atom derived from triazine are bonded to a phenyl group. Similarly, m / z 344.24 is thought to be a fragment in which one carbon and one nitrogen atom derived from triazine are bonded to a substituent other than the phenyl group. These fragments can be considered a characteristic feature of compounds with a triazine skeleton.

[0564] Figure 59 shows the results of measuring the refractive index of mmchmBPTzn using a spectroscopic ellipsometer (M-2000U, manufactured by J.A. Woolam Japan). For the measurement, a film was used in which each layer material was deposited on a quartz substrate by vacuum deposition, with a thickness of approximately 50 nm. The figure shows the refractive index of the ordinary ray (n,Ordinary) and the refractive index of the extraordinary ray (n,Extra-ordinary).

[0565] From this figure, it can be seen that mmchmBPTzn has a paraphotonic refractive index of 1.68 throughout the entire blue emission region (455 nm to 465 nm), which is in the range of 1.50 to 1.75, and also has a paraphotonic refractive index of 1.64 at 633 nm, which is in the range of 1.45 to 1.70, indicating that it is a material with a low refractive index.

[0566] Furthermore, good luminescence was obtained from light-emitting devices fabricated using this organic compound as an electron transport material. [Examples]

[0567] In this embodiment, a light-emitting device 6, a light-emitting device 7, and a comparative light-emitting device 3, which are aspects of the present invention, will be described. The structural formulas of the organic compounds used in this embodiment are shown below.

[0568] [ka]

[0569] (Methods for fabricating each light-emitting device) First, a first electrode 101 was formed on a glass substrate by sputtering indium tin oxide (ITSO) containing silicon oxide as a transparent electrode, with a film thickness of 110 nm. The electrode area was 4 mm². 2 (2mm x 2mm)

[0570] Next, as a pretreatment for forming a light-emitting device on the substrate, the substrate surface was washed with water, baked at 200°C for 1 hour, and then subjected to UV ozone treatment for 370 seconds.

[0571] Then, 10 -4 The substrate was introduced into a vacuum deposition apparatus where the internal pressure was reduced to approximately Pa. After vacuum firing at 170°C for 30 minutes in the heating chamber of the vacuum deposition apparatus, the substrate was allowed to cool for about 30 minutes.

[0572] Next, the substrate on which the first electrode 101 is formed is fixed to a substrate holder provided in a vacuum deposition apparatus so that the surface on which the first electrode 101 is formed faces downwards. Then, a hole injection layer 111 is formed on the first electrode 101 by co-depositing N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviated as PCBBiF) represented by the above structural formula (i) and an electron acceptor material (OCHD-001) at a weight ratio of 1:0.05 (=PCBBiF:OCHD-001) to a thickness of 10 nm using a vapor deposition method.

[0573] After depositing PCBBiF at a thickness of 20 nm onto the hole injection layer 111, N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviated as DBfBB1TP), represented by the above structural formula (ii), was deposited at a thickness of 10 nm to form a hole transport layer 112.

[0574] Next, an electron blocking layer was formed on the hole transport layer 112 by depositing 3,3'-(naphthalene-1,4-diyl)bis(9-phenyl-9H-carbazole) (abbreviated as PCzN2), represented by structural formula (iii), to a thickness of 10 nm.

[0575] Subsequently, 2-(10-phenyl-9-anthracenyl)-benzo[b]naphtho[2,3-d]furan (abbreviated as Bnf(II)PhA), represented by structural formula (iv), and 3,10-bis[N-(9-phenyl-9H-carbazole-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviated as 3,10PCA2Nbf(IV)-02), represented by structural formula (v), were co-deposited at a weight ratio of 1:0.015 (=Bnf(II)PhA:3,10PCA2Nbf(IV)-02) at a density of 25 nm to form the light-emitting layer 113.

[0576] Next, in the light-emitting device 6 and the comparative light-emitting device 3, a hole-blocking layer is formed by depositing 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)-1,1'-biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviated as mFBPTzn), represented by the above structural formula (vi), to a thickness of 10 nm. Then, in the light-emitting device 6, 2-(3,3'',5,5''-tetra-tert-butyl-1,1':3',1''-terphenyl-5'-yl)-4,6-diphenyl-1,3,5-triazine (abbreviated as mmtBumTPTzn), which is a low refractive index material of one aspect of the present invention shown as structural formula (121) in Embodiment 1, and structural formula (vi In comparative light-emitting device 3, an electron transport layer 114 was formed by co-depositing 20 nm of 6-methyl-8-quinolinolato-lithium (abbreviated as Li-6mq) represented by structural formula (viii) in a weight ratio of 1:1 (=mmtBumTPTzn:Li-6mq) with 2-[3-(2,6-dimethyl-3-pyridinyl)-5-(9-phenantrenyl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviated as mPn-mDMePyPTzn) represented by the above structural formula (viii) and 8-quinolinolato-lithium (abbreviated as Liq) represented by structural formula (ix) in a weight ratio of 1:1 (=mPn-mDMePyPTzn:Linm of co-deposited. Furthermore, after forming the light-emitting layer, in the light-emitting device 7, a hole blocking layer was formed by depositing mmtBumTPTzn to a thickness of 10 nm, and then an electron transport layer 114 was formed by co-depositing mmtBumTPTzn and Li-6mq at a weight ratio of 1:1 (=mmtBumTPTzn:Li-6mq) to a thickness of 20 nm.

[0577] Next, after forming the electron transport layer 114, an electron injection layer 115 was formed by depositing Liq to a thickness of 1 nm. Finally, aluminum was deposited to a thickness of 200 nm to form the second electrode 102, thereby fabricating each light-emitting device. The second electrode 102 is a reflective electrode that has the function of reflecting light, and the light-emitting device in this embodiment is a bottom-emission type element that extracts light from the first electrode 101.

[0578] Table 10 summarizes the element structures of light-emitting device 6, light-emitting device 7, and comparative light-emitting device 3.

[0579] [Table 10]

[0580] Table 11 shows the refractive indices at 456 nm for mmtBumTPTzn, mPn-mDMePyPTzn, Li-6mq, and Liq. The refractive indices were measured using a spectroscopic ellipsometer (M-2000U, J.A. Woolam Japan). For the measurement samples, films were used in which each layer material was deposited on a quartz substrate by vacuum deposition to a thickness of approximately 50 nm.

[0581] [Table 11]

[0582] Each of the above-mentioned light-emitting devices was sealed with a glass substrate in a glove box under a nitrogen atmosphere to prevent exposure to the atmosphere (sealant was applied around the element, UV treatment was performed during sealing, and heat treatment was performed at 80°C for 1 hour). After this, the initial characteristics of these light-emitting devices were measured. No special measures were taken to improve the removal efficiency of the sealed glass substrate.

[0583] Figure 45 shows the luminance-current density characteristics of light-emitting device 6, light-emit...

Claims

1. The organic compound comprises a first heteroaromatic ring which is a six-membered ring containing one to three nitrogen atoms, a plurality of aromatic hydrocarbon rings having six to fourteen carbon atoms forming the ring, and a plurality of hydrocarbon groups that form bonds in sp3 hybrid orbitals. Of the aforementioned multiple aromatic hydrocarbon rings, at least two are benzene rings. The two benzene rings are each bonded to the first heteroaromatic ring, The two benzene rings are, independently, substituted or unsubstituted phenyl groups and do not have hydrocarbon groups that form bonds in sp3 hybrid orbitals. The aforementioned organic compound has only one heteroaromatic ring, which is a six-membered ring containing one to three nitrogen atoms within its molecule. A material for light-emitting devices, wherein the ordinary refractive index of the layer made of the organic compound for light of any wavelength in the range of 455 nm to 465 nm is 1.5 to 1.

75.

2. The organic compound comprises a first heteroaromatic ring which is a six-membered ring containing one to three nitrogen atoms, a plurality of aromatic hydrocarbon rings having six to fourteen carbon atoms forming the ring, and a plurality of hydrocarbon groups that form bonds in sp3 hybrid orbitals. Of the aforementioned multiple aromatic hydrocarbon rings, at least two are benzene rings. The two benzene rings are each bonded to the first heteroaromatic ring, The two benzene rings are, independently, substituted or unsubstituted phenyl groups and do not have hydrocarbon groups that form bonds in sp3 hybrid orbitals. The aforementioned organic compound has only one heteroaromatic ring, which is a six-membered ring containing one to three nitrogen atoms within its molecule. A material for light-emitting devices, wherein the ratio of the total number of carbon atoms forming bonds in sp3 hybrid orbitals to the total number of carbon atoms in the molecule of the organic compound is 10% or more and 60% or less.

3. The organic compound comprises a first heteroaromatic ring which is a six-membered ring containing one to three nitrogen atoms, a plurality of aromatic hydrocarbon rings having six to fourteen carbon atoms forming the ring, and a plurality of hydrocarbon groups that form bonds in sp3 hybrid orbitals. Of the aforementioned multiple aromatic hydrocarbon rings, at least two are benzene rings. The two benzene rings are each bonded to the first heteroaromatic ring, The two benzene rings are, independently, substituted or unsubstituted phenyl groups and do not have hydrocarbon groups that form bonds in sp3 hybrid orbitals. The aforementioned organic compound has only one heteroaromatic ring, which is a six-membered ring containing one to three nitrogen atoms within its molecule. A material for light-emitting devices, wherein the integral value of signals less than 4 ppm in the measurement of the organic compound by 1H-NMR is 1 / 2 times or more the integral value of signals of 4 ppm or more.

4. The present invention includes an organic compound having a first heteroaromatic ring which is a six-membered ring containing one to three nitrogen atoms, and having multiple hydrocarbon groups that form bonds in sp3 hybrid orbitals, wherein a first benzene ring, a second benzene ring, and a third benzene ring are bonded to the first heteroaromatic ring, respectively. The first benzene ring is a substituted or unsubstituted first phenyl group and does not have a hydrocarbon group that forms a bond with an sp3 hybrid orbital. The second benzene ring is a substituted or unsubstituted second phenyl group and does not have a hydrocarbon group that forms a bond with an sp3 hybrid orbital. The aforementioned organic compound has only one heteroaromatic ring, which is a six-membered ring containing one to three nitrogen atoms within its molecule. A material for light-emitting devices, wherein the ordinary refractive index of the layer made of the organic compound for light of any wavelength in the range of 455 nm to 465 nm is 1.5 to 1.

75.

5. The present invention includes an organic compound having a first heteroaromatic ring which is a six-membered ring containing one to three nitrogen atoms, and having multiple hydrocarbon groups that form bonds in sp3 hybrid orbitals, wherein a first benzene ring, a second benzene ring, and a third benzene ring are bonded to the first heteroaromatic ring, respectively. The first benzene ring is a substituted or unsubstituted first phenyl group and does not have a hydrocarbon group that forms a bond with an sp3 hybrid orbital. The second benzene ring is a substituted or unsubstituted second phenyl group and does not have a hydrocarbon group that forms a bond with an sp3 hybrid orbital. The aforementioned organic compound has only one heteroaromatic ring, which is a six-membered ring containing one to three nitrogen atoms within its molecule. A material for light-emitting devices, wherein the ratio of the total number of carbon atoms forming bonds in sp3 hybrid orbitals to the total number of carbon atoms in the molecule of the organic compound is 10% or more and 60% or less.

6. The present invention includes an organic compound having a first heteroaromatic ring which is a six-membered ring containing one to three nitrogen atoms, and having multiple hydrocarbon groups that form bonds in sp3 hybrid orbitals, wherein a first benzene ring, a second benzene ring, and a third benzene ring are bonded to the first heteroaromatic ring, respectively. The first benzene ring is a substituted or unsubstituted first phenyl group and does not have a hydrocarbon group that forms a bond with an sp3 hybrid orbital. The second benzene ring is a substituted or unsubstituted second phenyl group and does not have a hydrocarbon group that forms a bond with an sp3 hybrid orbital. The aforementioned organic compound has only one heteroaromatic ring, which is a six-membered ring containing one to three nitrogen atoms within its molecule. A material for light-emitting devices, wherein the integral value of signals less than 4 ppm in the measurement of the organic compound by 1H-NMR is 1 / 2 times or more the integral value of signals of 4 ppm or more.

7. In any one of claims 1 to 6, The first heteroatom ring is a triazine ring, and the material is for light-emitting devices.

8. In any one of claims 1 to 6, The first heteroaromatic ring is a pyrimidine ring, and the material is for light-emitting devices.

9. In any one of claims 1 to 8, A material for light-emitting devices, wherein the molecular weight of the aforementioned organic compound is 500 or more and 2000 or less.

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