Light-emitting element, light-emitting device, electronic device, and lighting device

Abstract

To provide a light-emitting element with improved reliability, a light-emitting element with high current efficiency (or quantum efficiency), and a novel dibenzo[f,h]quinoxaline derivative that is preferably used for a light-emitting element according to one aspect of the present invention.SOLUTION: An EL layer is provided between an anode and a cathode. The EL layer includes a light-emitting layer. The light-emitting layer contains a first organic compound with electron transporting property and hole transporting property, a second organic compound with hole transporting property, and a light-emitting material. The first organic compound and the second organic compound are the combination that forms an excitation complex. The HOMO level of the first organic compound is lower than the HOMO level of the second organic compound. The difference between the HOMO level of the first organic compound and the HOMO level of the second organic compound is 0.4 eV or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an article, a method, or a manufacturing method. Alternatively, the present invention relates to a process, a machine , a manufacture, or a composition of matter. In particular , one aspect of the present invention relates to a light-emitting element, a light-emitting device, an electronic device, and a lighting device, a driving method thereof , or a manufacturing method thereof. Furthermore, the present invention relates to an organic compound that can be used for a light-emitting element, a light-emitting device, an electronic device, and a lighting device.

Background Art

[0002] A light-emitting element using an organic compound having characteristics such as thin and light weight, high-speed response, and driving with a low DC voltage as a light-emitting body is expected to be applied to the next-generation flat panel display. In particular , a display device in which light-emitting elements are arranged in a matrix is considered to have an advantage in that it has a wider viewing angle and better visibility compared to a conventional liquid crystal display device.

[0003] The light-emitting mechanism of the light-emitting element is that when a voltage is applied across an EL layer containing a light-emitting body between a pair of electrodes, electrons injected from the cathode and holes injected from the anode recombine at the light-emitting center of the EL layer to form molecular excitons, and when the molecular excitons relax to the ground state, energy is released to emit light. It is known that there are singlet excitation and triplet excitation in the excited state, and it is considered that light emission is possible through either excited state.

[0004] Regarding such a light-emitting element, in order to improve its element characteristics, improvements in the element structure and material development etc. are actively carried out (for example, see Patent Document 1).

Prior Art Documents

[0005] [Patent Document 1] JP 2010-182699 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the development of light-emitting devices, increasing the reliability of the devices is an important factor for commercialization. In order to improve the reliability of the element, the capacitance of the EL layer of the light-emitting element is A device configuration that allows control of rear balance and improves the probability of carrier recombination is required. Therefore, by forming the EL layer into a desired device configuration, carrier movement in the light-emitting layer can be improved. In addition, it is an object of the present invention to provide a light-emitting element having high current efficiency (or It is also important to obtain a high quantum efficiency in order to reduce the amount of current required for driving and to improve reliability. .

[0007] In view of this, one embodiment of the present invention provides a light-emitting element with improved reliability. Further, a light-emitting element according to one embodiment of the present invention is provided. In another aspect of the present invention, a novel organic compound is provided, which is preferably applied to the above-mentioned Light emitting element and light emitting device with high luminous efficiency and high reliability using the organic compound as an EL material In another aspect of the present invention, a novel material is provided. Another embodiment of the present invention provides a novel light-emitting element and a novel light-emitting device. The description of these problems does not preclude the existence of other problems. It is not necessary for the embodiment to solve all of these problems. It becomes obvious by itself from the descriptions in the specification, drawings, claims, etc., and it is possible to extract other problems from the descriptions in the specification, drawings, claims, etc.

Means for Solving the Problems

[0008] One aspect of the present invention has an EL layer between an anode and a cathode, the EL layer has a light-emitting layer, the light-emitting layer includes a first organic compound having electron-transporting and hole-transporting properties, a second organic compound having hole-transporting properties, and a light-emitting substance, the first organic compound and the second organic compound are a combination that forms an exciplex, the HOMO level of the first organic compound is lower than the HOMO level of the second organic compound, and the difference between the HOMO level of the first organic compound and the HOMO level of the second organic compound is 0.4 eV or less. It is a light-emitting device characterized by this.

[0009] Also, another aspect of the present invention has an EL layer between an anode and a cathode, the EL layer has a light-emitting layer, the light-emitting layer has a first organic compound having electron-transporting and hole-transporting properties, a second organic compound having hole-transporting properties, and a light-emitting substance, the first organic compound and the second organic compound are a combination that forms an exciplex, the first organic compound includes a 6-membered nitrogen-containing heteroaromatic ring and a carbazole skeleton and does not include a triarylamine skeleton, and the second organic compound includes a triarylamine skeleton. It is a light-emitting device characterized by this.

[0010] Also, another aspect of the present invention has an EL layer between an anode and a cathode, the EL layer has a light-emitting layer, the light-emitting layer has a first organic compound having electron-transporting and hole-transporting properties, a second organic compound having hole-transporting properties, and a light-emitting substance, the first organic compound and the second organic compound ​ A compound is a combination that forms an exciplex. The first organic compound contains a nitrogen-containing heteroaromatic ring composed of a 6-membered ring and a bicarbazole skeleton, and also contains a triarylamine skeleton. First, a light-emitting device is characterized in that the second organic compound contains a triarylamine skeleton.

[0011] Further, in the above configuration, the bicarbazole skeleton is a 3,3'-bicarbazole skeleton or a 2,3'-bicarbazole skeleton.

[0012] Further, in each of the above configurations, the light-emitting substance is a phosphorescent compound.

[0013] Further, in each of the above configurations, the EL layer includes a hole transport layer. The hole transport layer is in contact with the light-emitting layer, and the hole transport layer has a third organic compound having hole transport properties. The HOMO level of the third organic compound is lower than the HOMO level of the second organic compound.

[0014] Further, in each of the above configurations, the first organic compound is represented by the following general formula (G0).

[0015]

Chemical formula

[0016] However, in the formula, A represents a dibenzo[f,h]quinoxalinyl group, and R 1 ~R 15 each independently represents hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 5 to 7 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. ​​​​​​​​​represents either a base or [a certain group], and Ar represents a substituted or unsubstituted arylene group having 6 to 25 carbon atoms, or a single bond. Note that the arylene group of Ar does not include an anthracenylene group which is preferable.

[0017] Another aspect of the present invention is an organic compound represented by the following general formula (G0).

[0018]

Chemical formula

[0019] However, in the formula, A represents a dibenzo[f,h]quinoxalinyl group, and R 1 ~R 15 each independently represents hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 5 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, or either of them, and Ar represents a substituted or unsubstituted arylene group having 6 to 25 carbon atoms, or a single bond. Note that the arylene group of Ar does not include an anthracenylene group which is preferable. or a single bond. Note that the arylene group of Ar does not include an anthracenylene group which is preferable.

[0020] Another aspect of the present invention is an organic compound represented by the following general formula (G1).

[0021]

Chemical formula

[0022] However, in the formula, R 1 ~R 24 each independently represents hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 5 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, or either of them, and Ar represents a substituted or unsubstituted​ represents an arylene group having 6 to 25 carbon atoms or a single bond. Note that as the arylene group of Ar, it is preferably free of anthracenylene groups.

[0023] Another aspect of the present invention is an organic compound represented by the following general formula (G2).

[0024] [Chemical formula]

[0025] However, in the formula, R 1 ~R 24 each independently represents hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 5 to 7 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and Ar represents a substituted or unsubstituted arylene group having 6 to 25 carbon atoms or a single bond. Note that as the arylene group of Ar, it is preferably free of anthracenylene groups.

[0026] Another aspect of the present invention is an organic compound represented by the following general formula (G3).

[0027] [Chemical formula]

[0028] However, in the formula, R 1 ~R 24 each independently represents hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 5 to 7 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and Ar represents a substituted or unsubstituted arylene group having 6 to 25 carbon atoms or a single bond. Note that as the arylene group of Ar, Further, it is preferable that the anthracenylene group is not included.

[0029] In the general formula (G0), general formula (G2), and general formula (G3) described above, the alkyl group having 1 to 6 carbon atoms includes, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group , a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an isopentyl group , a hexyl group, and the like. Further, examples of the cycloalkyl group having 5 to 7 carbon atoms include, for example, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and the like. Examples of the aryl group having 6 to 13 carbon atoms include a phenyl group, a tolyl group, a xylyl group , a biphenyl group, an indenyl group, a naphthyl group, a fluorenyl group, and the like. Further, examples of the arylene group having 6 to 25 carbon atoms in Ar include 1,2- or 1,3- or 1 ,4-phenylene group, 2,6- or 3,5- or 2,4-tolylene group, 4,6-dimethylbenzene-1,3-diyl group , 2,4,6-trimethylbenzene-1,3-diyl group, 2,3,5,6-tetramethylbenzene-1,4-diyl group, 3,3'- or 3 ,4'- or 4,4'-biphenylene group, 1,1':3',1''-terphenyl-3,3''-diyl group, 1,1':4',1''-terphenyl-3,3''-diyl group, 1 ,1':4',1''-terphenyl-4,4''-diyl group, 1,1':3',1'' :3'',1'''-quarterphenyl-3,3'''-diyl group, 1,1':3',1'' :4'',1'''-quarterphenyl-3,4'''-diyl group, 1,1':4' ,1'':4'',1'''-quarterphenyl-4,4'''-diyl group, 1,4- ,1'':4'',1'''-quarterphenyl-4,4'''-diyl group, 1,4- ,1'':4'',1'''-quarterphenyl-4,4'''-diyl group, 1,4- ​​​​​​or a 1,5- or 2,6- or 2,7-naphthylene group, 2,7-fluorenylene group, 9,9-dimethyl-2,7-fluorenylene group, 9,9-diphenyl-2,7-fluoren ylene group, 9,9-dimethyl-1,4-fluorenylene group, spiro-9,9'-bifluo rene-2,7-diyl group, 9,10-dihydro-2,7-phenanthrenylene group, 2,7 -phenanthrenylene group, 3,6-phenanthrenylene group, 9,10-phenanthrenylene group, 2,7-triphenyleneylene group, 3,6-triphenyleneylene group, 2,8-benzo [a]phenanthrenylene group, 2,9-benzo[a]phenanthrenylene group, 5,8-benzo [c]phenanthrenylene group and the like can be mentioned.

[0030] In addition, the above-mentioned alkyl group having 1 to 6 carbon atoms, cycloalkyl group having 5 to 7 carbon atoms, aryl group having 6 to 13 carbon atoms, and arylene group having 6 to 25 carbon atoms may have a substituent, and the substituent is preferably an alkyl group having 1 to 6 carbon atoms such as a methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, isopentyl group, hexyl group, etc., a cycloalkyl group having 5 to 7 carbon atoms such as a cyclopentyl group, cyclohexyl group, cyclohept yl group, and an aryl group having 6 to 13 carbon atoms that forms a ring such as a phenyl group, tolyl group, xylyl group, bi phenyl group, indenyl group, naphthyl group, fluorenyl group, 9,9'-dimethylfluoren yl group.

[0031] Another aspect of the present invention is a light-emitting device using any one of the organic compounds of the above general formulas (G0) to (G3).

[0032] Another embodiment of the present invention is a light-emitting device including the light-emitting element having any of the above structures and a housing. be.

[0033] Note that one embodiment of the present invention is not only a light-emitting device having a light-emitting element, but also a light-emitting element or a light-emitting device Electronic equipment to which the device is applied (specifically, the light-emitting element or the light-emitting device and a connection terminal or an operating and a lighting device (specifically, a light-emitting element or a light-emitting device and a housing Therefore, the light-emitting device in this specification also includes a lighting device having a light-emitting body. The term "device" refers to an image display device or a light source (including lighting equipment). Connectors, such as FPC (Flexible printed circuit) or is a module equipped with a TCP (Tape Carrier Package), A module with a printed wiring board at the end of the TCP, or a light-emitting element with COG (Chi All modules with ICs directly mounted using the PO On Glass method are also This is included in the light-emitting device. Effect of the Invention

[0034] According to one aspect of the present invention, it is possible to provide novel dibenzo[f,h]quinoxaline derivatives. According to one aspect of the present invention, the dibenzo[f,h]quinoxaline derivative can be prepared by the method of The present invention relates to a light-emitting element, a light-emitting device, an electronic device, and an optical material having high luminous efficiency and high reliability. According to one embodiment of the present invention, a novel material can be provided. In another embodiment of the present invention, a novel light-emitting element and a light-emitting device are provided. The description of these effects does not preclude the existence of other effects. Note that one aspect of the present invention does not necessarily have all of these effects. Note that these other effects will become apparent from the descriptions in the specification, drawings, claims, etc., and it is possible to extract these other effects from the descriptions in the specification, drawings, claims, etc.

Brief Description of the Drawings

[0035]

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Embodiments for Carrying Out the Invention

[0036] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and its form and details can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention is not interpreted as being limited to the description of the embodiments shown below.

[0037] Note that the term "film" and the term "layer" can be interchanged with each other depending on the case or the situation. For example, the term "conductive layer" can be changed to the term "conductive film" in some cases. Or, for example, the term "insulating film" can be changed to the term "insulating layer" in some cases.

[0038] (Embodiment 1) ​​In this embodiment, a light-emitting element, which is one aspect of the present invention, will be described.

[0039] The light-emitting element shown in this embodiment has an EL layer including a light-emitting layer sandwiched between a pair of electrodes (a first electrode (anode) and a second electrode (cathode)) ) and the EL layer includes, in addition to the light-emitting layer, a hole (or hole) injection layer, a hole (or hole) transport layer, an electron transport layer, an electron injection layer, and the like, and is formed. formed.

[0040] When a voltage is applied to the light-emitting element, holes injected from the first electrode side and electrons injected from the second electrode side recombine in the light-emitting layer, and the energy generated thereby causes the light-emitting substance contained in the light-emitting layer to emit light.

[0041] At this time, the light-emitting layer 100 includes a first organic compound (h) 101 having electron transporting property and hole transporting property as shown in FIG. 1, a second organic compound (a) 102 having hole transporting property, and a light-emitting substance (not shown). The first organic compound (h) 101 and the second organic compound (a) 102 are a combination that forms an exciplex (also referred to as an exciplex). That is, at least the lowest unoccupied molecular orbital (LUMO) level of the first organic compound (h) 101 is lower than the LUMO level of the second organic compound (a) 102, and the highest occupied molecular orbital (HOMO) level of the first organic compound (h) 101 is lower than the HOMO level of the second organic compound (a) 102. Therefore, the excitation energy of the generated exciplex is as shown in the figure. 1 is lower than the LUMO level of the second organic compound (a) 102, and the highest occupied molecular orbital (HOMO) level of the first organic compound (h) 101 is lower than the HOMO level of the second organic compound (a) 102. Therefore, the excitation energy of the generated exciplex is as shown in the figure. Occupied Molecular Orbital) level is lower than the HOMO level of the second organic compound (a ) 102. Therefore, the excitation energy of the generated exciplex is as shown in the figure. ​​​​​​​As shown, the energy difference (i.e., ΔE in the figure) between the LUMO level (LUMO(h)) of the first organic compound (h) 101 and the HOMO level (HOMO(a)) of the second organic compound (a) 102 is affected. e ) is affected.

[0042] In such a light-emitting layer 100, energy transfer utilizing the overlap between the emission spectrum of the exciplex and the absorption spectrum of the light-emitting substance (guest material) can be performed. Therefore, a light-emitting device with high energy transfer efficiency and high external quantum efficiency can be realized. Also, in order to electrically excite the exciplex, electrical energy (i.e., voltage) corresponding to ΔE e is required, but this ΔE is smaller than the energy ΔE e required to electrically excite the first organic compound (h) 101 or the energy ΔE required to electrically excite the second organic compound (a) 102. That is, in such a light-emitting layer 100, the driving voltage (light h emission start voltage) of the light-emitting device can be reduced. a That is, in such a light-emitting layer 100, the driving voltage (light emission start voltage) of the light-emitting device can be reduced. emission start voltage) of the light-emitting device can be reduced.

[0043] In this case, even by using a single type of organic compound having a HOMO-LUMO gap corresponding to ΔE ΔE e in the light-emitting layer 10 0, a driving voltage (light emission start voltage) as low as that of the light-emitting layer 100 can be obtained. However, in the case of a single type of organic compound, the triplet excitation energy is significantly reduced compared to the singlet excitation energy. Therefore, it is difficult to transfer the triplet excitation energy to the light-emitting substance (guest material) and further contribute this to light emission. On the other hand, the exciplex However, in the case of a single type of organic compound, the triplet excitation energy is significantly reduced compared to the singlet excitation energy. Therefore, it is difficult to transfer the triplet excitation energy to the light-emitting substance (guest material) and further contribute this to light emission. On the other hand, the exciplex is such that the triplet excitation energy is much lower than the singlet excitation energy, so it is difficult to transfer the triplet excitation energy to the light-emitting substance (guest material) and further contribute this to light emission. On the other hand, the exciplex is such that the triplet excitation energy is much lower than the singlet excitation energy, so it is difficult to transfer the triplet excitation energy to the light-emitting substance (guest material) and further contribute this to light emission. On the other hand, the exciplex It has the characteristic that the singlet excitation energy and triplet excitation energy are located at almost the same position. Therefore, both singlet excitation energy and triplet excitation energy are transferred to the luminescent material. As a result, in addition to the effect of lowering the voltage, the effect of increasing efficiency can be obtained. The details of the mechanism of high efficiency mentioned here are as follows.

[0044] When the luminescent material is a phosphorescent compound, the singlet excitation energy and triplet excitation energy of the exciplex are The energy of both the phosphorescent compound and the triplet excited state is transferred to the triplet excited state. This is most preferable from the viewpoint of high efficiency because the emitted light from the

[0045] In addition, when the luminescent substance is a thermally activated delayed fluorescent compound, the singlet excitation energy of the exciplex is Energy is transferred to the singlet excited state of the luminescent material, and light is emitted from the singlet excited state (i.e. The triplet excitation energy of the exciplex can be converted into a luminescent material. Energy is transferred to the triplet excited state of the nucleonyl group, but the triplet excited state is partially or completely activated by thermal activation. or all of the luminescent material undergoes reverse intersystem crossing to the singlet excited state and is finally converted to fluorescent emission. Therefore, high efficiency can be achieved.

[0046] In addition, when the luminescent substance is a fluorescent compound, the singlet excitation energy of the exciplex is Energy is transferred to a singlet excited state, and light is emitted from the singlet excited state (i.e., fluorescence emission). On the other hand, the triplet excitation energy of the exciplex can be converted to the triplet excitation energy of the luminescent material. At first glance, it may not seem possible to achieve high efficiency because the energy is transferred to the activated state and thermally deactivated. However, the energy donor exciplexes can transfer singlet excitation energy and triplet excitation energy. Since the difference in excitation energy is small, the exciplex itself has the property of exhibiting thermally activated delayed fluorescence. In other words, the triplet excited state of the exciplex undergoes reverse intersystem crossing partially or entirely to the singlet excited state. The ratio of singlet excitons increases compared to normal. The proportion of singlet excitons increases, and the singlet excitation energy is transferred to the singlet excited state of the luminescent material. Since energy transfer occurs, even if a fluorescent compound is used as a luminescent material, This phenomenon is also one of the features of the present invention.

[0047] In this way, the light-emitting device in which the exciplex is used as the energy donor in the light-emitting layer can emit light with a phosphorescent compound. The present invention uses any of the following compounds as the luminescent substance: a thermally activated delayed fluorescent compound, a fluorescent compound, and a luminescent compound. Although this is useful in some cases, problems may arise in terms of controlling the light-emitting region.

[0048] As mentioned above, at least the LUMO level (LU The LUMO level (LUMO(h)) of the second organic compound (a) is higher than the LUMO level (LUMO(a)) of the second organic compound (a). The energy level is low, and the HOMO level of the first organic compound (h) 101 (HOMO (h)) is more energetic than the HOMO level (HOMO(a)) of the second organic compound (a)102. The low energy level of the first organic compound (h) 101 and the second organic compound (a) 10 In particular, in the conventional method, the exciplex is formed in the light-emitting layer 100. In the light-emitting device in which the first organic compound (h) 101 is used as an energy donor, O level (HOMO(h)) and the HOMO level of the second organic compound (a)102 (HOMO( a)) and the energy difference ΔE HOMO By making has been realized. For example, as the first organic compound (h) 101, 2-[3’-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenz[f,h]quinoxaline (abbreviation : 2mDBTBPDBq-II) was used, and as the second organic compound (a) 102, N-(1, 1’-biphenyl-4-yl)-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluorene-2-amine (abbreviation: PCBB iF). When used, the HOMO level (HOMO(h)) of the first organic compound (h) 101 is -6.22 eV, while the HOMO level (HO MO(a)) of the second organic compound (a) 102 is -5.36 eV. Therefore, ΔE is as large as 0.86 eV. HOMO

[0049] Thus, when the difference (ΔE ) between the HOMO level (HOMO(h)) of the first organic compound (h) 101 and the HOMO level (HOMO(a)) of the second organic compound (a) 102 is large HOMO , the carrier balance is likely to change significantly depending on the content of the second organic compound (a) 102 in the light-emitting layer 100. That is, if the second organic compound (a) 102 is too little, there will be an excess of electrons, that is, the light-emitting region will be biased towards the anode side. However, if it is just a little more than the optimal amount , this time there will be an excess of holes, that is, the holes will escape to the cathode side. In the case of such a device with a small margin , even if the mixing ratio of the first organic compound (h) 101 and the second organic compound (a) 102 is optimized exquisitely, if the carrier balance is slightly disrupted due to long-term driving , the recombination efficiency will be affected and decrease, resulting in luminance degradation. Also, ΔE HOM O ​​​​​When it is large, holes accumulate in the second organic compound (a) 102, so within the light-emitting layer 100 the width of the recombination region itself also becomes narrow. Conversely, the recombination region within the light-emitting layer 100 is wider because the entire area of the light-emitting layer 100 can be utilized, and it can be said that the reliability is higher.

[0050] In addition, in the light-emitting element, as the electron injection electrode (cathode) deteriorates, etc., the electron injection property deteriorates, so during long-term driving, the recombination region often shifts toward the cathode side. At this time, the average distance for transporting holes to the recombination region becomes longer, so if the light-emitting layer 100 has poor hole transportability, the resistance of the light-emitting element increases. In other words, when driven with a constant current, the driving voltage increases significantly over time. When the difference (ΔE ) between the HOMO level (HOMO(h)) of the first organic compound (h) and the HOMO level (HOMO(a)) of the second organic compound (a) is large HOMO , there is also a problem that this problem is likely to occur significantly because holes do not easily advance within the light-emitting layer 100.

[0051] Solving the problems in the light-emitting element using the above-mentioned exciplex as an energy donor in the light-emitting layer 100 is one aspect of the light-emitting element of the present invention. That is, an EL layer is provided between the anode and the cathode, and the EL layer has a light-emitting layer 100. The light-emitting layer 100 includes a first organic compound (h) 101 having electron transportability and hole transportability, a second organic compound (a) 102 having hole transportability, and a light-emitting substance. The first organic compound (h) 101 and the second organic compound (a) 102 are a combination that forms an exciplex. The HOMO level (HOMO(h)) of the first organic compound (h ) is the HOMO level (HO ) of the second organic compound (a) ​​​Lower than MO(a)), and the difference between the HOMO level (HOMO(h)) of the first organic compound (h) and the HOMO level (HOMO(a)) of the second organic compound (a) is 0.4 eV or less This is a light-emitting element characterized by the above.

[0052] With such a configuration, part of the holes is injected not only into the second organic compound (a) 102 but also into the first organic compound (h) 101. As a result, it becomes difficult for holes to accumulate in the second organic compound (a) 10 2, so it is easy to maintain carrier balance, and a light-emitting element with a wide recombination region within the light-emitting layer 100 can be obtained. Also, voltage increase during long-term driving (constant current driving) can be suppressed. In this case, recombination occurs partly in the first organic compound (h) 10 1, and an excited state of the first organic compound is also formed, but this is quickly converted to an exciplex, so the high-efficiency effect by using the above-mentioned exciplex can also be enjoyed. Also, since holes are mainly injected into the second organic compound (a) 102 the effect of lowering the driving voltage (light emission start voltage) is also maintained.

[0053] Thus, while making ΔE HOMO 0.4 eV or less (and greater than 0 eV), by forming an exciplex between the first organic compound (h) 101 and the second organic compound (a) 102, the above-mentioned problems can be solved. From the viewpoint of injecting holes not only into the second organic compound (a) 102 but also into the first organic compound (h) 101, ΔE is more preferably 0.3 eV or less. HOMO is more preferably 0.3 eV or less.

[0054] Also, compounds suitable for obtaining the above concept are as follows. First, the first organic compound (h)101 preferably contains a nitrogen-containing heteroaromatic ring of a 6-membered ring and a carbazole skeleton, and does not contain a triarylamine skeleton. That is, while imparting electron transporting properties by means of a nitrogen-containing heteroaromatic ring of a 6-membered ring, a compound having an appropriate hole transporting property by containing a carbazole skeleton and not containing a triarylamine skeleton is preferred. On the other hand, the second organic compound (a)102 is a compound having hole transporting properties, and preferably contains a triarylamine skeleton in order to have a higher HOMO level than the first organic compound (h)101. Many compounds containing a triarylamine skeleton have a HOMO level of around -5.5 eV or higher according to cyclic voltammetry (CV) measurement. On the other hand, since the HOMO level of simple 9-phenylcarbazole is -5.88 eV, the difference often becomes 0.4 eV or more. Therefore, in one aspect of the present invention, the carbazole skeleton of the first organic compound (h)101 preferably contains a bicarbaazole skeleton. This is because bicarbaazole has a higher HOMO level than 9-phenylcarbazole. In particular, when a 3,3'-bicarbaazole skeleton or a 2,3'-bicarbaazole skeleton is introduced, the HOMO level becomes around -5.6 to -5.7 eV, which is suitable for the first organic compound (h)101 in one aspect of the present invention. While imparting electron transporting properties by means of a nitrogen-containing heteroaromatic ring of a 6-membered ring, a compound having an appropriate hole transporting property by containing a carbazole skeleton and not containing a triarylamine skeleton is preferred. On the other hand, the second organic compound (a)102 is a compound having hole transporting properties, and preferably contains a triarylamine skeleton in order to have a higher HOMO level than the first organic compound (h)101. Many compounds containing a triarylamine skeleton have a HOMO level of around -5.5 eV or higher according to cyclic voltammetry (CV) measurement. On the other hand, since the HOMO level of simple 9-phenylcarbazole is -5.88 eV, the difference often becomes 0.4 eV or more. Therefore, in one aspect of the present invention, the carbazole skeleton of the first organic compound (h)101 preferably contains a bicarbaazole skeleton.

[0055] This is because bicarbaazole has a higher HOMO level than 9-phenylcarbazole. In particular, when a 3,3'-bicarbaazole skeleton or a 2,3'-bicarbaazole skeleton is introduced, the HOMO level becomes around -5.6 to -5.7 eV, which is suitable for the first organic compound (h)101 in one aspect of the present invention. Many compounds containing a triarylamine skeleton have a HOMO level of around -5.5 eV or higher according to cyclic voltammetry (CV) measurement. On the other hand, since the HOMO level of simple 9-phenylcarbazole is -5.88 eV, the difference often becomes 0.4 eV or more. Therefore, in one aspect of the present invention, the carbazole skeleton of the first organic compound (h)101 preferably contains a bicarbaazole skeleton. This is because bicarbaazole has a higher HOMO level than 9-phenylcarbazole. In particular, when a 3,3'-bicarbaazole skeleton or a 2,3'-bicarbaazole skeleton is introduced, the HOMO level becomes around -5.6 to -5.7 eV, which is suitable for the first organic compound (h)101 in one aspect of the present invention. In addition, examples of the above-mentioned nitrogen-containing heteroaromatic ring of a 6-membered ring include diazines such as pyridine, pyrazine, pyrimidine, and pyridazine, as well as triazine and tetrazine. These nitrogen-containing heteroaromatic rings of 6-membered rings may further have a benzene ring or the like condensed thereto. For example, benzene In addition, examples of the above-mentioned nitrogen-containing heteroaromatic ring of a 6-membered ring include diazines such as pyridine, pyrazine, pyrimidine, and pyridazine, as well as triazine and tetrazine. These nitrogen-containing heteroaromatic rings of 6-membered rings may further have a benzene ring or the like condensed thereto. For example, benzene

[0056] In addition, examples of the above-mentioned nitrogen-containing heteroaromatic ring of a 6-membered ring include diazines such as pyridine, pyrazine, pyrimidine, and pyridazine, as well as triazine and tetrazine. These nitrogen-containing heteroaromatic rings of 6-membered rings may further have a benzene ring or the like condensed thereto. For example, benzene In addition, examples of the above-mentioned nitrogen-containing heteroaromatic ring of a 6-membered ring include diazines such as pyridine, pyrazine, pyrimidine, and pyridazine, as well as triazine and tetrazine. These nitrogen-containing heteroaromatic rings of 6-membered rings may further have a benzene ring or the like condensed thereto. For example, benzene In addition, examples of the above-mentioned nitrogen-containing heteroaromatic ring of a 6-membered ring include diazines such as pyridine, pyrazine, pyrimidine, and pyridazine, as well as triazine and tetrazine. These nitrogen-containing heteroaromatic rings of 6-membered rings may further have a benzene ring or the like condensed thereto. For example, benzene Examples of the nitrogen-containing heteroaromatic ring of the 6-membered ring with condensed rings include quinoline, isoquinoline, and dibenzo f,h]quinoline. Further, naphthyridine typified by quinoxaline, quinazoline, and phthalazine, and dibenzo[f,h]quinoxaline, dibenzo[f,h]quinazoline etc. are also useful.

[0057] In addition, in one aspect of the present invention, as described above, not only the second organic compound (a) 102, but also it is preferable to inject and transport holes into the first organic compound (h) 101. Therefore, as shown in FIG. 2, in order to enhance the hole injection property into both the first organic compound (h) 101 and the second organic compound (a) 102 in the light-emitting layer 100, a third organic compound (p) 105 having hole transportability is used in the hole transport layer 104 in contact with the light-emitting layer 100, and the HOMO level (HOMO(p)) of the third organic compound (p) 105 is preferably made lower than the HOMO level (HOMO(a)) of the second organic compound (a) 102. In particular, it is more preferable to select the third organic compound (p) 105 such that the HOMO level (HOMO(p)) of the third organic compound (p) 105 is between the HOMO level (HOMO(a)) of the second organic compound (a) 102 and the HOMO level (HOMO(h)) of the first organic compound (h) 101. (a) 102 and the HOMO level (HOMO(h)) of the first organic compound (h) 101.

[0058] Hereinafter, a specific example of the light-emitting device according to one aspect of the present invention having the above configuration will be described with reference to FIG. 3.

[0059] For the first electrode (anode) 201 and the second electrode (cathode) 203, metals, alloys, electrically conductive compounds, and mixtures thereof can be used. Specifically, indium oxide ​​​​​​Indium Tin Oxide, silicon or silicon oxide-containing Indium Tin Oxide, Indium Zinc Oxide ide, indium oxide containing tungsten oxide and zinc oxide, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo ), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), titanium (Ti) In addition, elements belonging to Group 1 or Group 2 of the periodic table, that is, alkali metals such as lithium (Li) and cesium (Cs), and alkaline earth metals such as calcium (Ca) and strontium (Sr) , magnesium (Mg), and alloys containing these (MgAg, Al Li), rare earth metals such as europium (Eu) and ytterbium (Yb) and alloys containing these, and others such as graphene can be used. Note that the first electrode (anode) 201 and the second electrode (cathode) 203 can be formed by, for example, sputtering or vapor deposition (including vacuum vapor deposition) and the like.

[0060] The hole injection layer 211 is a layer that injects holes into the light-emitting layer 213 through a hole transport layer 212 with high hole transport properties, and is a layer containing a substance with high hole transport properties (also referred to as a hole transport compound) and an acceptor substance. By containing a substance with high hole transport properties and an acceptor substance, electrons are drawn from the substance with high hole transport properties by the acceptor substance to generate holes, and the holes are injected into the light-emitting layer 213 through the hole transport layer 212. Note that the hole transport layer 2 12 is formed using a substance with high hole transport properties.

[0061] As a high hole-transporting material used for the positive hole injection layer 211 and the hole transport layer 212, for example, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB or α-NPD), N,N'-bis(3-methylphenyl)-N,N'-diphe nyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4',4 ''-tris(carbazol-9-yl)triphenylamine (abbreviation: TCTA), 4, 4',4''-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDA TA), 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino triphenylamine (abbreviation: MTDATA), 4,4'-bis[N-(spiro-9,9 '-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), etc. Any aromatic amine compound, 3-[N-(9-phenylcarbazol-3-yl)-N-f enylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarb azole (abbreviation: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phen ylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN 1), etc. can be mentioned. In addition, 4,4'-di(N-carbazolyl)biphenyl (abbreviation: C BP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: T CPB), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carb azole (abbreviation: CzPA), etc. of carbazole derivatives, etc. can be used. Here The substances described are mainly 1×10 -6 cm 2It is a substance having a hole mobility of 1 / Vs or more. However, as long as it is a substance with higher hole transportability than electrons, other substances may be used.

[0062] Furthermore, high molecular compounds such as poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N’-[4-(4-diphenylamino)phenyl]phenyl-N’-phenylamino}phenyl)methacrylamide] ( abbreviation: PTPDMA), poly[N,N’-bis(4-butylphenyl)-N,N’-bis (phenyl)benzidine] (abbreviation: Poly-TPD) can also be used. Moreover, as the acceptor substance used for the hole injection layer 211, metal oxides belonging to Groups 4 to 8 in the periodic table can be mentioned. Specifically, molybdenum oxide is particularly preferable. It is also possible.

[0063] The light-emitting layer 213 is a layer containing a light-emitting substance. However, when the light-emitting layer 213 has the configuration shown in FIG. 1, a first organic compound having electron transportability and hole transportability described later, a second organic compound having the above-described hole transportability, and a light-emitting substance are included. Also, the first organic

[0064] compound and the second organic compound are a combination capable of forming an exciplex (also referred to as an exciplex) at the time of recombination of carriers (electrons and holes) in the light-emitting layer. In the light-emitting layer, when an exciplex is formed, the fluorescence spectra of the first organic compound and the second organic compound are converted into the emission spectrum of the exciplex located on the longer wavelength side. And the emission spectrum of the exciplex and the absorption spectrum of the guest material In the light-emitting layer, by forming an exciplex, the fluorescence spectra of the first organic compound and the second organic compound are converted into the emission spectrum of the exciplex located on the longer wavelength side. And the emission spectrum of the exciplex and the absorption spectrum of the guest material at the time of recombination of carriers (electrons and holes) in the light-emitting layer can form an exciplex (also called an exciplex). In the light-emitting layer, when an exciplex is formed, the fluorescence spectra of the first organic compound and the second organic compound are converted into the emission spectrum of the exciplex located on the longer wavelength side. And the fluorescence spectra of the first organic compound and the second organic compound are converted into the emission spectrum of the exciplex located on the longer wavelength side. And the emission spectrum of the exciplex and the absorption spectrum of the guest material Select the first organic compound and the second organic compound so that the overlap with the spectrum becomes large, so that the energy transfer from the singlet excited state can be maximally enhanced. Note that Regarding the triplet excited state, it is considered that energy transfer occurs from the exciplex rather than the host material.

[0065] As the first organic compound and the second organic compound, any combination that forms an exciplex may be used, but it is preferable to combine a compound that easily accepts electrons (electron trap compound) and a compound that easily accepts holes (hole trap compound). Since the first organic compound preferably can trap (or transport) not only electrons but also holes, a compound containing a nitrogen-containing heteroaromatic ring composed of a 6-membered ring and a bicarbazole skeleton and not containing a triarylamine skeleton is preferable. For example, a compound represented by the following general formula (G0) is preferred. preferred.

[0066] [Chemical formula]

[0067] (In the formula, A represents a dibenzo[f,h]quinoxalinyl group, and R 1 ~R 15 each independently represents hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 5 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and Ar represents a substituted or unsubstituted arylene group having 6 to 25 carbon atoms, or represents a single bond. Note that as the arylene group of Ar, it is preferable that an anthracenylene group is not included. )

[0068] ​​​In addition, when Ar contains an anthracenylene group, the triplet excitation energy of the compound becomes large (1 .7 eV or less), and the triplet excitation energy of the exciplex is quenched . Therefore, it is preferable that the arylene group of Ar does not contain an anthracenylene group .

[0069] More specifically, the compounds represented by the above general formulas (G1) to (G3) are preferable. Even more specifically, for example, 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzof[h]quinoxaline (abbreviation: 2PCCzPDBq), 2-{3-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzof[h]quinoxaline (abbreviation: 2mPCCzPDBq), 2-{4-[2-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzof[h]quinoxa line (abbreviation: 2PCCzPDBq-02), and 2-{3-[2-(N-phenyl-9 H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzof h]quinoxaline (abbreviation: 2mPCCzPDBq-02) can be mentioned .

[0070] In addition, as a compound that easily receives holes, for example, 4-phenyl-4'-(9-phen enyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP) , 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino] -9-phenylcarbazole (abbreviation: PCzPCN1), 4,4',4''-tris[N ​​-(1-Naphthyl)-N-phenylamino]triphenylamine (abbreviation: 1’-TNAT A), 2,7-bis[N-(4-diphenylaminophenyl)-N-phenylamino]- Spiro-9,9’-bifluorene (abbreviation: DPA2SF), N,N’-bis(9-phenyl carbazol-3-yl)-N,N’-diphenylbenzene-1,3-diamine (abbreviation : PCA2B), N-(9,9-dimethyl-2-N’,N’-diphenylamino-9H- Fluoren-7-yl)diphenylamine (abbreviation: DPNF), N,N’,N’’-tri phenyl-N,N’,N’’-tris(9-phenylcarbazol-3-yl)benzene -1,3,5-triamine (abbreviation: PCA3B), 2-[N-(9-phenylcarbazol -3-yl)-N-phenylamino]spiro-9,9’-bifluorene (abbreviation: PCA SF), 2-[N-(4-diphenylaminophenyl)-N-phenylamino]spiro- 9,9’-bifluorene (abbreviation: DPASF), N,N’-bis[4-(carbazol- 9-yl)phenyl]-N,N’-diphenyl-9,9-dimethylfluorene-2,7- diamine (abbreviation: YGA2F), 4,4’-bis[N-(3-methylphenyl)-N-f enylamino]biphenyl (abbreviation: TPD), 4,4’-bis[N-(4-diphenyl amino)phenyl]-N-phenylamino]biphenyl (abbreviation: DPAB), N-(9,9- dimethyl-9H-fluorene-2-yl)-N-{9,9-dimethyl-2[N’-phenyl -N’-(9,9-dimethyl-9H-fluorene-2-yl)amino]-9H-fluoro rene-7-yl}phenylamine (abbreviation: DFLADFL), 3-[N-(9-phenyl carbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3-[N-(4-diphenylaminophenyl)-N-phenylamino -9-phenylcarbazole (abbreviation: PCzDPA1), 3,6-bis[N-(4-di phenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA2), 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N' -phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviation: DNTPD) , 3,6-bis[N-(4-diphenylaminophenyl)-N-(1-naphthyl)amino -9-phenylcarbazole (abbreviation: PCzTPN2), 3,6-bis[N-(9-f enylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole ( abbreviation: PCzPCA2), etc., compounds having a triarylamine skeleton are exemplified.

[0071] The above-mentioned first organic compound and second organic compound are not limited to these specific examples, but are a combination capable of forming an exciplex, and the emission spectrum of the exciplex overlaps with the absorption spectrum of the luminescent substance, and the peak of the emission spectrum of the exciplex is longer in wavelength than the peak of the absorption spectrum of the luminescent substance.

[0072] In addition, when the first organic compound and the second organic compound are composed of a compound that easily accepts electrons and a compound that easily accepts holes, the carrier balance can be controlled by the mixing ratio. Specifically, the range of the first organic compound: the second organic compound = 1:9 to 9:1 is preferable.

[0073] In the light-emitting layer 213, materials that can be used as the luminescent substance and the luminescence center substance A luminescent substance that converts singlet excitation energy into luminescence, or a luminescent substance that converts triplet excitation energy into luminescence, etc. can be used alone or in combination. The above-mentioned luminescent substances and luminescent center substances include, for example, the following. As the luminescent substance that converts singlet excitation energy into luminescence, for example, substances that emit fluorescence (fluorescent compounds) can be mentioned. Examples of substances that emit fluorescence include N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazol-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-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), N,N''-(2-tert-butylanthracene-9,10-diyl-di-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:

[0074] As the luminescent substance that converts singlet excitation energy into luminescence, for example, substances that emit fluorescence (fluorescent compounds) can be mentioned.

[0075] Examples of substances that emit fluorescence include N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazol-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-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), N,N''-(2-tert-butylanthracene-9,10-diyl-di-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: N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S) 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA) 4-(9H-carbazol-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-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA) N,N''-(2-tert-butylanthracene-9,10-diyl-di-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: N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: Name: 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl -N,N’,N’-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPP A), 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-anth ryl)-N,N’,N’-triphenyl-1,4-phenylenediamine (abbreviation: 2DPA PA), N-[9,10-bis(1,1’-biphenyl-2-yl)-2-anthryl] -N,N’,N’-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPh A), 9,10-bis(1,1’-biphenyl-2-yl)-N-[4-(9H-carb azole-9-yl)phenyl]-N-phenylanthracene-2-amine (abbreviation: 2YG ABPhA), N,N,9-triphenylanthracene-9-amine (abbreviation: DPhAP hA), coumarin 545T, N,N’-diphenylquinacridone (abbreviation: DPQd), ru brene, 5,12-bis(1,1’-biphenyl-4-yl)-6,11-diphenyltetra racene (abbreviation: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]ethe nyl}-6-methyl-4H-pyran-4-ylidene)propanedinitrile (abbreviation: DCM 1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-be {2-Isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile Dicyanomethylene-2-methyl-6-(4-dicyanomethylene-2-methyl-6-(4-dimethylaminostyryl)-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]fluoranthene-3,10-diamine (abbreviation: p-mPhAFD), {2-isopropyl- 6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5 H-benzo[ij]quinolin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI), {2-tert-butyl-6-[2-(1, 1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij H-benzo[ij]quinolin-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 1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij quinolin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), etc. Examples include dicyanomethylene-2-methyl-6-(4-dicyanomethylene-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran-4-ylidene)propane dinitrile (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]fluoranthene-3,10-diamine (abbreviation: p-mPhAFD), {2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI), {2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolin-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]quinolin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), etc. Examples thereof include substances that emit phosphorescence (phosphorescent compounds) and TADF materials that exhibit thermally activated delayed fluorescence (TADF) (thermally activated delayed fluorescent compounds). The delayed fluorescence in TADF materials is the same as normal fluorescence. Examples of the luminescent substance that converts triplet excitation energy into luminescence include, for example, substances that emit phosphorescence (phosphorescent compounds) and TADF materials that exhibit thermally activated delayed fluorescence (TADF) (thermally activated delayed fluorescent compounds). The delayed fluorescence in TADF materials is the same as normal fluorescence. Examples of the luminescent substance that converts triplet excitation energy into luminescence include, for example, substances that emit phosphorescence (phosphorescent compounds) and TADF materials that exhibit thermally activated delayed fluorescence (TADF) (thermally activated delayed fluorescent compounds). The delayed fluorescence in TADF materials is the same as normal fluorescence. Examples thereof include substances that emit phosphorescence (phosphorescent compounds) and TADF materials that exhibit thermally activated delayed fluorescence (TADF) (thermally activated delayed fluorescent compounds). The delayed fluorescence in TADF materials is the same as normal fluorescence. include substances that emit phosphorescence (phosphorescent compounds) and TADF materials that exhibit thermally activated delayed fluorescence (TADF) (thermally activated delayed fluorescent compounds). The delayed fluorescence in TADF materials is the same as normal fluorescence.

[0076] Examples of the luminescent substance that converts triplet excitation energy into luminescence include, for example, substances that emit phosphorescence (phosphorescent compounds) and TADF materials that exhibit thermally activated delayed fluorescence (TADF) (thermally activated delayed fluorescent compounds). The delayed fluorescence in TADF materials is the same as normal fluorescence. Examples of the luminescent substance that converts triplet excitation energy into luminescence include, for example, substances that emit phosphorescence (phosphorescent compounds) and TADF materials that exhibit thermally activated delayed fluorescence (TADF) (thermally activated delayed fluorescent compounds). The delayed fluorescence in TADF materials is the same as normal fluorescence. Examples of the luminescent substance that converts triplet excitation energy into luminescence include, for example, substances that emit phosphorescence (phosphorescent compounds) and TADF materials that exhibit thermally activated delayed fluorescence (TADF) (thermally activated delayed fluorescent compounds). The delayed fluorescence in TADF materials is the same as normal fluorescence. Refers to luminescence that has a spectrum and an extremely long lifespan. The lifespan is 10 -6 seconds or more, preferably 10 -3 seconds or more.

[0077] Examples of substances that emit phosphorescence include bis{2-[3’,5’-bis(trifluoromethyl)phenyl]pyridinato-N,C }iridium(III) picolinate (abbreviation: Ir(CF 2’ ppy) 3 (pic)), bis[2-(4’,6’-difluorophenyl)pyridinato 2 -N,C iridium(III) acetylacetonate (abbreviation: FIracac), 2’ tris(2-phenylpyridinato)iridium(III) (abbreviation: Ir(ppy) 3 ) bis(2-phenylpyridinato)iridium(III) acetylacetonate (abbreviation: I r(ppy) 2 (acac)), tris(acetylacetonato)(monophenanthroline(acac)), terbium(III) (abbreviation: Tb(acac) 3 (Phen)), bis(benzo[h(Phen)), bis(benzo[h quinolinato)iridium(III) acetylacetonate (abbreviation: Ir(bzq) 2 ( acac)), bis(2,4-diphenyl-1,3-oxazolato-N,C 2’ )iridium (III) acetylacetonate (abbreviation: Ir(dpo) 2 (acac)), bis{ 2-[4’-(perfluorophenyl)phenyl]pyridinato-N,C 2’}iridium (III) acetylacetonate (abbreviation: Ir(p-PF-ph) 2 (acac)), bis (2-phenylbenzothiazolato-N,C 2’)Iridium(III) acetylacetonate nart (abbreviation: Ir(bt) 2 (acac)), bis[2-(2'-benzo[4,5-a thienyl)pyridinato-N,C 3’ iridium(III) acetylacetonate (abbreviation : Ir(btp) 2 (acac)), bis(1-phenylisoquinolinato-N,C 2’ )iridium(III) acetylacetonate (abbreviation: Ir(piq) 2 (acac)) , (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato iridium(III) (abbreviation: Ir(Fdpq) 2 (acac)), (acetylacetonato nat)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III) (abbreviation : [Ir(mppr-Me) 2 (acac)]), (acetylacetonato)bis(5-i sopropyl-3-methyl-2-phenylpyrazinato)iridium(III) (abbreviation: [I r(mppr-iPr) 2 (acac)]), (acetylacetonato)bis(2,3,5 -triphenylpyrazinato)iridium(III) (abbreviation: Ir(tppr) 2 (aca c)), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato)iridi um(III) (abbreviation: [Ir(tppr) 2 (dpm)]), (acetylacetonato) bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation : [Ir(tBuppm) 2 (acac)]), (acetylacetonato)bis(4,6- diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm)2 (aca c)]), 2,3,7,8,12,13,17,18 - octaethyl - 21H,23H - porphyrin platinum(II) (abbreviation: PtOEP), tris(1,3 - diphenyl - 1,3 - propanedionato)(monophenanthroline)europium(III) (abbreviation: Eu( DBM) 3 (Phen)), tris[1 - (2 - thenoyl) - 3,3,3 - trifluoro acetonato](monophenanthroline)europium(III) (abbreviation: Eu(TTA) 3 (Phen)) and the like can be mentioned.

[0078] Also, as the TADF material, for example, fullerenes and their derivatives, act inine derivatives such as proflavin, eosin and the like can be mentioned. Also, magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or para dium (Pd) and the like can be mentioned. Metal - containing porphyrins include, for example, protoporphyrin - tin fluoride complex (SnF (Proto IX) 2 ), mesoporphyrin - tin fluoride complex (SnF (Meso IX)), hematoporph 2 yrin - tin fluoride complex (SnF (Hemato IX)), coproporphyrin tetra 2 methyl ester - tin fluoride complex (SnF (Copro III - 4Me)), oct 2 aethylporphyrin - tin fluoride complex (SnF (OEP)), etioporphyrin - 2 tin fluoride complex (SnF (Etio I)), octaethylporphyrin - platinum chloride complex 2 (PtCl ), 2Examples include OEP). Furthermore, 2-(biphenyl-4-yl)-4, 6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3 ,5-triazine (PIC-TRZ) and other heteroaromatic rings with π-excessive type and hetero aromatic rings with π-deficient type can also be used. Note that a substance in which a π-excessive type heteroaromatic ring and a π -deficient type heteroaromatic ring are directly bonded has both the donor property of the π-excessive type heteroaromatic ring and the acceptor property of the π -deficient type heteroaromatic ring enhanced, and the energy difference between S1 and T1 becomes small , so it is particularly preferable.

[0079] In addition, the light-emitting layer 213 may have a laminated structure as shown in FIG. 3(B). However, in this case, it shall be configured such that light emission can be obtained from each of the laminated layers. For example, from the first-layer light-emitting layer 213(a1), it may be configured to obtain fluorescence emission, and from the second-layer light-emitting layer 213(a2) laminated on the first layer, it may be configured to obtain phosphorescence emission. Note that the lamination order may be reversed. Also, in the layer where phosphorescence emission is obtained, it is preferably configured such that emission is obtained by energy transfer from an exciplex to a dopant. Also, regarding the emission color, when it is configured such that blue emission is obtained from one layer, orange emission or yellow emission or the like may be obtained from the other layer. Also, in each layer, it may be configured to contain a plurality of types of dopants. The electron transport layer 214 is a layer containing a substance with high electron transport property (also referred to as an electron transport compound). In the electron transport layer 214, tris(8-quinolinolato)aluminum(III) (abbreviation : Alq

[0080] 3 ​​​), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation : Almq 3 ), bis(10-hydroxybenzo[h]quinolinato)beryllium (abbreviation: BeBq 2 ), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)al uminum(III) (abbreviation: BAlq), bis[2-(2-hydroxyphenyl)benzo oxazolato]zinc(II) (abbreviation: Zn(BOX) 2 ), bis[2-(2-hydroxy phenyl)benzothiazolato]zinc(II) (abbreviation: Zn(BTZ) 2 ), and other metal complexes can be used. Also, 2-(4-biphenylyl)-5-(4-tert-butyl phenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p -tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene( abbreviation: OXD-7), 3-(4’-tert-butylphenyl)-4-phenyl-5-( 4’’-biphenyl)-1,2,4-triazole (abbreviation: TAZ), 3-(4-ter t-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenylyl)-1, 2,4-triazole (abbreviation: p-EtTAZ), bathophenanthroline (abbreviation: BPh en), bathocuproin (abbreviation: BCP), 4,4’-bis(5-methylbenzoxa zol-2-yl)stilbene (abbreviation: BzOs), and other heteroaromatic compounds can also be used . Also, poly(2,5-pyridinediyl) (abbreviation: PPy), poly[(9,9- dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbre viation: PF-Py), poly[(9,9-dioctylfluorene-2,7-diyl)-co- Polymers such as (2,2'-bipyridine-6,6'-diyl) (abbreviation: PF-BPy) can also be used. The substances described herein mainly have an electron mobility of 1×10 -6 cm 2 / Vs or higher. As long as the substance has higher electron transportability than holes, substances other than the above may be used as the electron transport layer 214.

[0081] In addition, the electron transport layer 214 may not only be a single layer, but also have a structure in which two or more layers made of the above substances are laminated. It may be a structure formed by laminating.

[0082] The electron injection layer 215 is a layer containing a substance with high electron injection properties. The electron injection layer 215 may use lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF ), 2 etc., such as alkali metals, alkaline earth metals, or their compounds. In addition, rare earth metal x compounds such as erbium fluoride (ErF ) can be used. In addition, electride may be used for the electron injection layer 215. 3 As the electride, for example, substances obtained by adding electrons to a mixed oxide of calcium and aluminum at a high concentration can be mentioned. In addition, the substances constituting the above-described electron transport layer 214 can also be used.

[0083] In addition, a composite material obtained by mixing an organic compound and an electron donor (donor) may be used for the electron injection layer 215. Such a composite material generates electrons in the organic compound by the electron donor, so it has excellent electron injection properties and electron transport properties. In this case, as the organic compound, since electrons are generated in the organic compound by the electron donor, it is excellent in electron injection properties and electron transport properties. In this case, as the organic compound, It is preferably a material excellent in the transport of generated electrons. Specifically, for example, the materials (such as metal complexes and heteroaromatic compounds) constituting the electron transport layer 214 described above can be used. As the electron donor, any material that exhibits electron-donating properties with respect to organic compounds may be used. Specifically, alkali metals, alkaline earth metals, and rare earth metals are preferable, and examples include lithium, cesium, magnesium, calcium, erbium, ytterbium, etc. Also, alkali metal oxides and alkaline earth metal oxides are preferable, and examples include lithium oxide, calcium oxide, barium oxide, etc. Further, a Lewis base such as magnesium oxide can also be used. In addition, organic compounds such as tetrathiafulvalene (abbreviation: TTF) can also be used. Note that the above-described hole injection layer 211, hole transport layer 212, light-emitting layer 213, electron transport layer 214, and electron injection layer 215 can be formed by methods such as vapor deposition (including vacuum vapor deposition), inkjet method, and coating method, respectively. The above-described light-emitting device emits light when holes and electrons recombine in the EL layer 202. And this light is taken out to the outside through either one or both of the first electrode 201 and the second electrode 203. Therefore, either one or both of the first electrode 201 and the second electrode 203 are electrodes having translucency. Note that the light-emitting device shown in this embodiment can perform energy transfer using the overlap between the emission spectrum of the exciplex and the absorption spectrum of the phosphorescent compound (guest material).

[0084]

[0085]

[0086] ​​​​​​​​​​Thus, a light-emitting device with high energy transfer efficiency and high external quantum efficiency can be realized.

[0087] In addition, the configuration shown in this embodiment can be used in appropriate combination with the configuration shown in other embodiments. It is assumed that this is possible.

[0088] (Embodiment 2) In this embodiment, a dibenzo[f,h]quinoxaline derivative, which can be used in a light-emitting device and is one aspect of the present invention, will be described. h]quinoxaline derivative will be described.

[0089] A dibenzo[f,h]quinoxaline derivative, which is one aspect of the present invention, is represented by the following general formula (G0). It is represented.

[0090]

Chemical formula

[0091] However, in the formula, A represents a dibenzo[f,h]quinoxalinyl group, and R 1 ~R 15 each independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 5 to 7 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and Ar represents a substituted or unsubstituted arylene group having 6 to 25 carbon atoms, or a single bond. Note that it is preferable that the arylene group of Ar does not include an anthracenylene group. or a single bond. Note that it is preferable that the arylene group of Ar does not include an anthracenylene group. or a single bond. Note that it is preferable that the arylene group of Ar does not include an anthracenylene group. or a single bond. Note that it is preferable that the arylene group of Ar does not include an anthracenylene group. This is preferable.

[0092] In addition, the dibenzo[f,h]quinoxaline derivative represented by the above general formula (G0) can be synthesized by the synthesis method shown below. First, as shown in the following synthesis scheme (a), a halogen compound (A1) of a dibenzo[f,h]quinoxaline derivative and bicarba azole By reacting with an arylboronic acid compound (A2) of the derivative, a dibenzo[f,h quinoxaline derivative (G0) is obtained.

[0093] [Chemical formula]

[0094] In the formula, A represents a dibenzo[f,h]quinoxalinyl group, and R 1 ~R 15 each independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 5 to 7 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Ar represents a substituted or unsubstituted arylene group having 6 to 25 carbon atoms, or a single bond. It is preferable that the arylene group of Ar does not include an anthracenylene group. Further, X represents a halogen. When Ar is a substituted or unsubstituted arylene group having 6 to 25 carbon atoms, B represents boric acid, a boronic acid ester, a cyclic triol borate salt, etc. As the cyclic triol borate salt, in addition to the lithium salt, a potassium salt or a sodium salt may also be used. When Ar is a single bond, B represents hydrogen. In addition, as shown in the following synthesis scheme (b), a halogen compound (A1) of a dibenzo[f,h]quinoxaline derivative and an arylboronic acid (B1) substituted with a halogen are reacted to obtain an intermediate (B2), and then reacted with a bicarbolide derivative (B3) to obtain a dibenzo[f,h]quinoxaline derivative (G0). In addition, when Ar is a substituted or unsubstituted arylene group having 6 to 25 carbon atoms, B represents boric acid, a boronic acid ester, or a cyclic triol borate salt. As the cyclic triol borate salt, in addition to the lithium salt, a potassium salt or a sodium salt may also be used. When Ar is a single bond, B represents hydrogen. In addition, as shown in the following synthesis scheme (b), a halogen compound (A1) of a dibenzo[f,h]quinoxaline derivative and an arylboronic acid (B1) substituted with a halogen are reacted to obtain an intermediate (B2), and then reacted with a bicarbolide derivative (B3) to obtain a dibenzo[f,h]quinoxaline derivative (G0).

[0095] In addition, as shown in the following synthesis scheme (b), a halogen compound (A1) of a dibenzo[f,h]quinoxaline derivative and an arylboronic acid (B1) substituted with a halogen are reacted to obtain an intermediate (B2), and then reacted with a bicarbolide derivative (B3) to obtain a dibenzo[f,h]quinoxaline derivative (G0). In addition, as shown in the following synthesis scheme (b), a halogen compound (A1) of a dibenzo[f,h]quinoxaline derivative and an arylboronic acid (B1) substituted with a halogen are reacted

[0096] [Chemistry]

[0097] In the formula, A represents a dibenzo[f,h]quinoxalinyl group, and R 1 ~R 15 each independently represents hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 5 to 7 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Ar represents a substituted or unsubstituted arylene group having 6 to 25 carbon atoms or a single bond. Note that the anthracenylene group is preferably not included as the arylene group of Ar. Also, X represents a halogen. Further, B represents boric acid, a boronic acid ester, a cyclic triol borate salt, or the like. When Ar in the general formula (G0) represents a single bond, (A1) and (B3) may be reacted as they are. Next, a dibenzo [f,h]quinoxaline derivative, which is one embodiment of the present invention that can be synthesized by the above-described synthesis method or the like, is more preferably a compound represented by the above general formulas (G1) to (G3). Also, specific structural formulas of the dibenzo[f,h]quinoxaline derivatives, which are one embodiment of the present invention represented by the general formulas (G0) to (G3), are shown below (the following structural formulas (1 00) to (131)). However, the present invention is not limited thereto.

[0098]

[0099] [f,h]quinoxaline derivative is preferably a compound represented by the above general formulas (G1) to (G3). Also, the dibenzo[f,h]quinoxaline derivative, which is one embodiment of the present invention represented by the general formulas (G0) to (G3), is preferably a compound represented by the above general formulas (G1) to (G3). 00) to (131)). However, the present invention is not limited thereto.

[0100] [Chemistry]

[0101] [Chemistry] ​​​​​​​

[0102] [Chemical formula]

[0103] [Chemical formula]

[0104] [Chemical formula]

[0105] [Chemical formula]

[0106] Note that by using the dibenzo[f,h]quinoxaline derivative, which is one aspect of the present invention, in one aspect of the present invention in a certain light-emitting element, a light-emitting element, a light-emitting device, an electronic device or a lighting device with high luminous efficiency and reliability can be realized. Also, a light-emitting element, a light-emitting device with low power consumption, an electronic device, or a lighting device can be realized.

[0107] In addition, the dibenzo[f,h]quinoxaline derivatives represented by general formulas (G0) to (G3) have electron-transporting and hole-transporting properties, so they can be used as a host material for the light-emitting layer, or as an electron-transporting layer or a hole-transporting layer. Also, since they exhibit fluorescence emission, they can be used as a light-emitting substance of the light-emitting element itself. Thus, the dibenzo[f,h]quinoxaline derivatives represented by general formulas (G0) to (G3) are useful novel compounds with a wide range of usage methods as materials for light-emitting elements. Therefore, the dibenzo represented by general formulas (G0) to (G3) quinoxaline derivatives are The light-emitting element containing the dibenzo[f,h]quinoxaline derivative is a light-emitting element according to one aspect of the present invention.

[0108] Note that the configuration shown in this embodiment can be used in appropriate combination with the configurations shown in other embodiments. It can be used.

[0109] (Embodiment 3) In this embodiment, as a light-emitting element according to one aspect of the present invention, a light-emitting element having a structure in which a plurality of EL layers are sandwiching a charge generation layer (hereinafter referred to as a tandem type light-emitting element) will be described. Note that the tandem type light-emitting element has a plurality of EL layers (the first EL layer 402(1), the second EL layer 40 2(2)) between a pair of electrodes (the first electrode 401 and the second electrode 404) as shown in Fig. 4(A). It has.

[0110] Note that in this embodiment, the first electrode 401 is an electrode that functions as an anode, and the second electrode 404 is an electrode that functions as a cathode. Also, the first electrode 401 and the second electrode 404 can use the same configuration as in Embodiment 1. Also, the plurality of EL layers ( the first EL layer 402(1), the second EL layer 402(2)) may have the same configuration as the EL layer shown in Embodiment 1, or any of them may have the same configuration. That is, the first EL layer 402(1) and the second EL layer 402(2) may have the same configuration or different configurations and the configuration can be the same as that in Embodiment 1. Further either of the plurality of EL layers (the first EL layer 402(1), the second EL layer 402(2)) can use the dibenzo[f,h]quinoxaline derivative shown in Embodiment 2.

[0111] In addition, between the multiple EL layers (the first EL layer 402(1) and the second EL layer 402(2)), The charge generating layer 405 is provided between the first electrode 401 and the second electrode 402. When a voltage is applied to the electrode 404, electrons are injected into one EL layer and holes are injected into the other EL layer. In the present embodiment, the first electrode 401 is connected to the second electrode 40. When a voltage is applied so that the potential becomes higher than that of the first EL layer 404, the charge generating layer 405 emits light to the first EL layer 404. Electrons are injected into second EL layer 402(1) and holes are injected into second EL layer 402(2).

[0112] The charge generating layer 405 is transparent to visible light from the viewpoint of light extraction efficiency. (Specifically, it is preferable that the transmittance of visible light through the charge generating layer 405 is 40% or more.) In addition, the charge generating layer 405 has a lower electrical conductivity than the first electrode 401 and the second electrode 404. But it still works.

[0113] The charge generation layer 405 is formed by adding an electron acceptor to an organic compound having a high hole transporting property. Even if the structure is such that an electron donor is added to an organic compound with high electron transport properties, In addition, both of these configurations may be laminated.

[0114] In the case where an electron acceptor is added to an organic compound having high hole transport properties, Examples of organic compounds with high transport properties include NPB, TPD, TDATA, MTDATA, 4,4'-Bis[N-(spiro-9,9'-bifluoren-2-yl)-N-phenyla Aromatic amine compounds such as bis(amino)biphenyl (abbreviation: BSPB) can be used. The substances mentioned here are mainly 1×10 -6 cm 2a substance having a hole mobility of 0.1 cm2 / Vs or more However, as long as it is an organic compound with higher hole transportability than electrons, substances other than the above may be used.

[0115] In addition, examples of the electron acceptor include 7,7,8,8 - tetracyano - 2,3,5,6 - tetrafluoroquinodimethane (abbreviation: F - TCNQ), chloranil, etc. Further, transition metal oxides can be mentioned. Also, oxides of metals belonging to Groups 4 to 8 in the periodic table of elements can be mentioned. Specifically, vanadium oxide, niobium oxide, 4 tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide are preferable because they have high electron - accepting properties. Among them, molybdenum oxide is particularly preferable because it is stable in the air, has low hygroscopicity, and is easy to handle.

[0116] On the other hand, in the case of a configuration in which an electron donor is added to an organic compound with high electron transportability, as the organic compound with high electron transportability, for example, Alq 3 , Almq 3 , BeBq 2 , B Alq, etc., metal complexes having a quinoline skeleton or a benzoquinoline skeleton can be used. In addition, Zn(BOX) , Zn(BTZ) 2 and other metal complexes having oxazole - based or thiazole - based ligands can also be used. Furthermore, in addition to metal complexes, 2 PBD, OXD - 7, TAZ, BPhen, BCP, etc. can also be used. The substances described here are mainly substances having an electron mobility of 1×10-4 cm2 / Vs or more. -6 cm 2 ​​​​​​​​​​In addition, any organic compound with higher electron transportability than holes can be used instead of the above substances without problem. It doesn't matter.

[0117] Moreover, as the electron donor, an alkali metal, an alkaline earth metal, a rare earth metal, or a metal belonging to Groups 2 and 13 in the periodic table and its oxides and carbonates can be used. Specifically, it is possible to use lithium (Li), cesium (Cs), magnesium (Mg), calcium (Ca), ytterbium (Yb), indium (In), lithium oxide, cesium carbonate, etc. It is also preferable to use an organic compound such as tetrathianaphthacene as the electron donor.

[0118] Note that by forming the charge generation layer 405 using the above-described materials, it is possible to suppress an increase in the driving voltage when the EL layer is laminated.

[0119] In this embodiment, a light-emitting device having two EL layers has been described. However, as shown in FIG. 4(B), even for a light-emitting device in which n EL layers (where n is 3 or more) (402(1) to 402(n)) are laminated, the same can be applied. When there are a plurality of EL layers between a pair of electrodes as in the light-emitting device according to this embodiment, by disposing charge generation layers (405(1) to 405(n - 1)) between the EL layers, respectively, it is possible to emit light in a high-luminance region while keeping the current density low. Since the current density can be kept low, a long-life device can be realized. Further, when applied to a light-emitting device, an electronic device, an illumination device, etc. having a large light-emitting surface, the voltage drop due to the resistance of the electrode material can be reduced, so that uniform light emission over a large area becomes possible.

[0120] Also, by making the emission colors of the respective EL layers different, it is possible to obtain emission of a desired color for the entire light-emitting element. For example, in a light-emitting element having two EL layers, by making the emission color of the first EL layer and the emission color of the second EL layer be in a complementary color relationship, it is possible to obtain a light-emitting element that emits white light as the entire light-emitting element. Note that complementary colors refer to the relationship between colors that become achromatic when mixed. That is, by mixing lights of colors in a complementary color relationship with each other, white light emission can be obtained. Specifically, a combination in which blue light emission is obtained from the first EL layer and yellow light emission (or orange light emission) is obtained from the second EL layer can be mentioned. In this case, it is not necessary for both the blue light emission and the yellow light emission (or orange light emission) to be the same fluorescence emission or phosphorescence emission. A combination in which the blue light emission is fluorescence emission and the yellow light emission (or orange light emission) is phosphorescence emission, or the reverse combination may be used. Furthermore, it is preferable to adopt a stacked structure suitable for adjusting the

[0121] optical path length in the light-emitting element (for example, a configuration in which yellow light emission is obtained from the first light-emitting layer and blue light emission is obtained from the second light-emitting layer), so that the element characteristics can be further improved.

[0122] In addition, the same applies to a light-emitting element having three EL layers. For example, when the emission color of the first EL layer is red, the emission color of the second EL layer is green, and the emission color of the

[0123] (Embodiment 4) In this embodiment, a colored layer (such as a color filter) is combined with the light-emitting element described in the first embodiment. In this embodiment, a light-emitting device in which the light-emitting element and the light-emitting diode are combined will be described. The configuration of the pixel section of the device will be described with reference to FIG.

[0124] In FIG. 5, a plurality of FETs (transistors) 502 are formed on a substrate 501. The ET 502 is electrically connected to each light emitting element (507R, 507G, 507B, 507Y). Specifically, each FET 502 is connected to a first electrode 503 which is a pixel electrode of a light-emitting element. In addition, a partition wall 5 is formed to fill the ends of the adjacent first electrodes 503. 04 is provided.

[0125] In addition, the first electrode 503 in this embodiment has a function as a reflective electrode. An EL layer 505 is formed on the first electrode 503, and a second An electrode 510 is formed on the EL layer 505. The EL layer 505 has a plurality of light-emitting elements each emitting a plurality of monochromatic lights. The second electrode 510 is an electrode that functions as a semi-transmissive and semi-reflective electrode. be.

[0126] Each light-emitting element (507R, 507G, 507B, 507Y) emits a different light. Specifically, the light emitting element 507R is optically adjusted to obtain red light emission. In the region indicated by 506R, red light passes through the colored layer 508R in the direction of the arrow. The light emitting element 507G is optically adjusted to emit green light. In the region indicated by 506G, green light is emitted in the direction of the arrow through the colored layer 508G. The light emitting element 507B is optically adjusted to emit blue light. In the region indicated by 06B, blue light is emitted in the direction of the arrow through the coloring layer 508B. The light-emitting element 507Y is optically adjusted so that yellow light emission can be obtained, and yellow light is emitted in the direction of the arrow through the coloring layer 508Y in the region indicated by 506 Y.

[0127] Each coloring layer (508R, 508G, 508B, 508Y) is provided on a transparent sealing substrate 511 disposed above the substrate 501 on which each light-emitting element (507R, 507G, 507B, 507Y) is provided, as shown in FIG. 5. Each coloring layer (508R, 508G , 508B, 508Y) is provided at a position overlapping each light-emitting element (507R, 507G , 507B, 507Y) that exhibits each emission color. Each coloring layer (508R, 508G , 508B, 508Y) is provided at a position overlapping each light-emitting element (507R, 507G , 507B, 507Y) that exhibits each emission color.

[0128] In addition, a black layer (black matrix) 509 is provided to fill the ends of adjacent coloring layers (508R, 508G, 508B, 508Y). Each coloring layer (508R , 508G, 508B, 508Y) and the black layer 509 may be covered with an overcoat layer using a transparent material.

[0129] In the configuration described above, a light-emitting device having a structure (top emission type) that extracts light on the side of the sealing substrate 511 is obtained. However, a structure (bottom emission type) that extracts light on the side of the substrate 501 on which the FET is formed may also be used. In the case of the top emission type light-emitting device shown in the present embodiment, a light-shielding substrate and a light-transmitting substrate can be used as the substrate 501. However, in the case of a bottom emission type light-emitting device, it is necessary to use a light-transmitting substrate as the substrate 501.

[0130] ​​​​​​For example, in this specification and the like, transistors and light-emitting elements can be formed using various substrates. The type of substrate is not limited to a specific one. As an example of the substrate, there are semiconductor substrates (e.g., single-crystal substrates or silicon substrates), SOI substrates, glass substrates, quartz substrates, plastic substrates, metal substrates, stainless-steel substrates, substrates having a stainless-steel foil, tungsten substrates, substrates having a tungsten foil, flexible substrates, laminated films, paper containing fibrous materials, or base films and the like. As an example of the glass substrate, there are barium borosilicate glass, aluminoborosilicate glass, or soda lime glass and the like. Examples of flexible substrates, laminated films, base films, etc. include the following. For example, plastics typified by polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), and polytetrafluoroethylene (PTFE). Or, synthetic resins such as acrylic, or films made of polypropylene, polyester, polyvinyl fluoride, vinyl chloride, etc., films made of polyamide, polyimide, aramid, epoxy, etc., inorganic vapor deposition films, or papers and the like. In particular, by manufacturing transistors using semiconductor substrates, single-crystal substrates, or SOI substrates, etc., transistors with less variation in characteristics, size, or shape, high current supply ability, and small size can be manufactured. When a circuit is configured with such transistors, low power consumption of the circuit or high integration of the circuit can be achieved. Moreover, as the substrate, a flexible substrate is used, and transistors and light-emitting elements are directly formed on the flexible substrate.

[0131] ​ It may be formed. Alternatively, a release layer may be provided between the substrate and transistors or the like. The release layer is used to separate from the substrate after partially or completely completing a semiconductor device thereon and transfer it to another substrate for mounting. At that time, transistors or the like can be transferred to a substrate with poor heat resistance or a flexible substrate. Note that, for example, a laminated structure of an inorganic film of a tungsten film and a silicon oxide film, or a structure in which an organic resin film such as polyimide is formed on a substrate can be used for the above-described release layer.

[0132] That is, a transistor or a light-emitting element may be formed using a certain substrate, and then the transistor or the light-emitting element may be transposed to another substrate and the transistor or the light-emitting element may be arranged on another substrate. As an example of the substrate to which the transistor or the light-emitting element is transposed, in addition to the substrate on which the above-described transistors or the like can be formed there are a paper substrate, a cellophane substrate, an aramid film substrate, a polyimide film substrate, a stone substrate, a wood substrate, a cloth substrate (including natural fibers (silk, cotton, linen), synthetic fibers( nylon, polyurethane, polyester) or recycled fibers (acetate, cupra, rayon, recycled polyester), etc.), a leather substrate, or a rubber substrate. By using these substrates, it is possible to form transistors or the like with good characteristics, form transistors or the like with low power consumption, manufacture a device that is difficult to break, impart heat resistance, reduce weight, or make it thinner

[0133] Note that the configuration shown in this embodiment can be used in appropriate combination with the configuration shown in other embodiments

[0134] (Embodiment 5) ​​​​In this embodiment, a light-emitting device having a light-emitting element using a dibenzo[f,h]quinoxaline derivative, which is one aspect of the present invention, will be described for an EL layer.

[0135] Further, the above light-emitting device may be a passive matrix type light-emitting device or an active matrix type light-emitting device. Note that the light-emitting elements described in other embodiments can be applied to the light-emitting device shown in this embodiment.

[0136] In this embodiment, an active matrix type light-emitting device will be described with reference to FIG. 6.

[0137] Note that FIG. 6(A) is a top view showing the light-emitting device, and FIG. 6(B) is a cross-sectional view taken along the dashed line A -A' in FIG. 6(A). The active matrix type light-emitting device according to this embodiment includes a pixel portion 602 provided on an element substrate 601, a driving circuit portion (source line driving circuit) 6 03, and driving circuit portions (gate line driving circuits) 604a and 604b. The pixel portion 6 02, the driving circuit portion 603, and the driving circuit portion 604 are sealed between the element substrate 601 and a sealing substrate 606 by a sealing material 605.

[0138] Further, on the element substrate 601, a routing wiring 607 for connecting external input terminals for transmitting an external signal (for example, a video signal, a clock signal, a start signal, or a reset signal, etc.) or a potential to the driving circuit portion 603 and the driving circuit portions 604a and 604b is provided. Here, an example in which an FPC (flexible printed circuit) 608 is provided as an external input terminal is shown. Note that only the FPC is illustrated here, but a printed wiring board (PWB) may be attached to this FPC. In the light-emitting device described in this specification ​ This shall include not only the light-emitting device body but also the state in which an FPC or PWB is attached thereto. Be so.

[0139] Next, the cross-sectional structure will be described with reference to FIG. 6(B). On the element substrate 601, a drive circuit section and a pixel section are formed. Here, the drive circuit section 603, which is a source line drive circuit, and the pixel section 602 are shown.

[0140] The drive circuit section 603 is exemplified as having a configuration combining FET609 and FET610. Note that the drive circuit section 603 may be formed of a circuit including a unipolar (either N-type or P-type only) transistor, or may be formed of a CMOS circuit including an N-type transistor and a P-type transistor. Also, in the present embodiment, a driver integrated type in which a drive circuit is formed on a substrate is shown, but a drive circuit may also be formed externally.

[0141] Also, the pixel section 602 is formed by a plurality of pixels including a switching FET611, a current control FET612, and a first electrode (anode) 613 electrically connected to the wiring (source electrode or drain electrode) of the current control FET612. Also, in the present embodiment, the pixel section 602 is shown as an example configured by two FETs, namely a switching FET611 and a current control FET612, but is not limited thereto. For example, the pixel section 602 may be a combination of three or more FETs and a capacitive element.

[0142] As FET609, 610, 611, and 612, for example, staggered or inverse-staggered transistors can be applied. What is used for FET609, 610, 611, and 612 ​​​​​​As the semiconductor material that can be used, for example, group 13 (such as gallium) semiconductors, group 14 (such as silicon) semiconductors, compound semiconductors, oxide semiconductors, and organic semiconductor materials can be used. Also, regarding the crystallinity of the semiconductor material, there is no particular limitation, and for example, an amorphous semiconductor film or a crystalline semiconductor film can be used. In particular, for FET609, 610, 611, 612 it is preferable to use an oxide semiconductor. Examples of the oxide semiconductor include In- Ga oxide, In-M-Zn oxide (M is Al, Ga, Y, Zr, La, Ce, or Nd), etc. As FET609, 610, 611, 612, for example, by using an oxide semiconductor material with a bandgap of 2 eV or more, preferably 2.5 eV or more, and more preferably 3 eV or more, the off-current of the transistor can be reduced.

[0143] Also, an insulator 614 is formed covering the end portion of the first electrode 613. Here, the insulator 614 is formed by using a positive-type photosensitive acrylic resin. Also, in this embodiment, the first electrode 613 is used as an anode.

[0144] Moreover, it is preferable that a curved surface having a curvature is formed at the upper end portion or the lower end portion of the insulator 614. By forming the shape of the insulator 614 as described above, the coating property of the film formed on the upper layer of the insulator 614 can be made good. For example, as the material of the insulator 614, either a negative-type photosensitive resin or a positive-type photosensitive resin can be used, and it is not limited to organic compounds, and inorganic compounds such as silicon oxide, silicon oxynitride, and silicon nitride can also be used.

[0145] On the first electrode (anode) 613, an EL layer 615 and a second electrode (cathode) 616 are laminated. The EL layer 615 is provided with at least a light-emitting layer. Also, in the EL layer 61 5, in addition to the light-emitting layer, a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, a charge generation layer, etc. can be appropriately provided.

[0146] Note that a light-emitting element 617 is formed in a laminated structure with the first electrode (anode) 613, the EL layer 615, and the second electrode (cathode) 616. As the materials used for the first electrode (anode) 613, the EL layer 615, and the second electrode (cathode) 616, the materials shown in Embodiment 2 can be used. Also, although not shown here, the second electrode (cathode) 616 is electrically connected to an FPC 608 that is an external input terminal. In the cross-sectional view shown in FIG. 6(B), only one light-emitting element 617 is shown, but in the pixel portion 6 02, it is assumed that a plurality of light-emitting elements are arranged in a matrix. In the pixel portion 60 2, light-emitting elements capable of obtaining three types (R, G, B) of light emission are selectively formed respectively, and a light-emitting device capable of full-color display can be formed. Also, in addition to the light-emitting elements capable of obtaining three types (R, G, B) of light emission, for example, light-emitting elements capable of obtaining light emission such as white (W), yellow (Y), magenta (M ) cyan (C), etc. may be formed. For example, by adding light-emitting elements capable of obtaining several types of the above-described light emission to the light-emitting elements capable of obtaining three types (R,

[0147] G, B) of light emission, effects such as improvement of color purity and reduction of power consumption can be obtained. Also, it may be a light-emitting device capable of full-color display by combining with a color filter. Furthermore, a light-emitting device with improved luminous efficiency and reduced power consumption by combination with quantum dots can be obtained. Also, by combining with a color filter, a light-emitting device capable of full-color display can be obtained. Further, by combining with quantum dots, the luminous efficiency can be improved and the power consumption can be reduced. ), cyan (C), etc. may be formed. For example, by adding light-emitting elements capable of obtaining several types of the above-described light emission to the light-emitting elements capable of obtaining three types (R, G, B) of light emission, effects such as improvement of color purity and reduction of power consumption can be obtained. Also, it may be a light-emitting device capable of full-color display by combining with a color filter. Furthermore, a light-emitting device with improved luminous efficiency and reduced power consumption by combination with quantum dots can be obtained. device can be obtained. It may also be arranged.

[0148] Furthermore, by bonding the sealing substrate 606 to the element substrate 601 with the sealing material 605, a structure is formed in which the light-emitting element 617 is provided in the space 618 surrounded by the element substrate 601, the sealing substrate 606, and the sealing material 605. In addition to the case where the space 618 is filled with an inert gas (such as nitrogen or argon), the structure also includes a configuration in which the sealing material 605 is filled.

[0149] It is preferable to use an epoxy resin or glass frit for the sealing material 605. Also, these materials are desirably materials that do not permeate moisture and oxygen as much as possible. In addition, as materials used for the sealing substrate 606 and the element substrate 601, in addition to glass substrates and quartz substrates, plastic substrates made of FRP (Fiber-Reinforced Plastics), PVF (polyvinyl fluoride), polyester, acrylic, or the like can be used. (Fiber-Reinforced Plastics), PVF (polyvinyl fluoride) ide), polyester, or acrylic can be used. When using glass frit as the sealing material, from the viewpoint of adhesiveness, it is preferable that the element substrate 601 and the sealing substrate 606 are glass substrates.

[0150] As described above, an active matrix type light-emitting device can be obtained.

[0151] Note that the configuration shown in this embodiment can be used by appropriately combining the configurations shown in other embodiments.

[0152] (Embodiment 6) In this embodiment, an example of various electronic devices completed by applying a light-emitting device which is one aspect of the present invention will be described with reference to FIG. 7.

[0153] As an electronic device to which a light-emitting device is applied, for example, a television device (also referred to as a TV or a television receiver), a monitor for a computer, a digital camera, a digital video camera, a camera such as a digital photo frame, a mobile phone (also referred to as a mobile phone or a mobile phone device), a portable game machine, a portable information terminal, an audio reproduction device, a large game machine such as a pachinko machine, etc. can be mentioned. Specific examples of these electronic devices are shown in FIG. 7. A monitor for a computer, a digital camera, a digital video camera, a camera such as a digital photo frame, a mobile phone (also referred to as a mobile phone or a mobile phone device), a portable game machine, a portable information terminal, an audio reproduction device, a large game machine such as a pachinko machine, etc. can be mentioned. A monitor for a computer, a digital camera, a digital video camera, a camera such as a digital photo frame, a mobile phone (also referred to as a mobile phone or a mobile phone device), a portable game machine, a portable information terminal, an audio reproduction device, a large game machine such as a pachinko machine, etc. can be mentioned. A monitor for a computer, a digital camera, a digital video camera, a camera such as a digital photo frame, a mobile phone (also referred to as a mobile phone or a mobile phone device), a portable game machine, a portable information terminal, an audio reproduction device, a large game machine such as a pachinko machine, etc. can be mentioned. Specific examples of these electronic devices are shown in FIG. 7.

[0154] FIG. 7(A) shows an example of a television device. The television device 7100 has a display unit 7103 incorporated in a housing 7101. The display unit 7103 can display an image, and it may be a touch panel (input / output device) equipped with a touch sensor (input device). Note that the light-emitting device, which is one aspect of the present invention, can be used for the display unit 7103. Here, a configuration in which the housing 7101 is supported by a stand 7105 is shown. The television device 7100 has a display unit 7103 incorporated in a housing 7101. The display unit 7103 can display an image, and it may be a touch panel (input / output device) equipped with a touch sensor (input device). Note that the light-emitting device, which is one aspect of the present invention, can be used for the display unit 7103. Here, a configuration in which the housing 7101 is supported by a stand 7105 is shown. The television device 7100 has a display unit 7103 incorporated in a housing 7101. The display unit 7103 can display an image, and it may be a touch panel (input / output device) equipped with a touch sensor (input device). Note that the light-emitting device, which is one aspect of the present invention, can be used for the display unit 7103. Here, a configuration in which the housing 7101 is supported by a stand 7105 is shown. The television device 7100 has a display unit 7103 incorporated in a housing 7101. The display unit 7103 can display an image, and it may be a touch panel (input / output device) equipped with a touch sensor (input device). Note that the light-emitting device, which is one aspect of the present invention, can be used for the display unit 7103. Here, a configuration in which the housing 7101 is supported by a stand 7105 is shown. The television device 7100 has a display unit 7103 incorporated in a housing 7101. The display unit 7103 can display an image, and it may be a touch panel (input / output device) equipped with a touch sensor (input device). Note that the light-emitting device, which is one aspect of the present invention, can be used for the display unit 7103. Here, a configuration in which the housing 7101 is supported by a stand 7105 is shown. The television device 7100 has a display unit 7103 incorporated in a housing 7101. The display unit 7103 can display an image, and it may be a touch panel (input / output device) equipped with a touch sensor (input device). Note that the light-emitting device, which is one aspect of the present invention, can be used for the display unit 7103. Here, a configuration in which the housing 7101 is supported by a stand 7105 is shown.

[0155] The operation of the television device 7100 can be performed by operation switches provided in the housing 7101 or by a separate remote control unit 7110. Channel and volume operations can be performed by operation keys 7109 provided on the remote control unit 7110, and the image displayed on the display unit 7103 can be operated. Further, the remote control unit 7110 may be configured to be provided with a display unit 7107 for displaying information output from the remote control unit 7110. The operation of the television device 7100 can be performed by operation switches provided in the housing 7101 or by a separate remote control unit 7110. Channel and volume operations can be performed by operation keys 7109 provided on the remote control unit 7110, and the image displayed on the display unit 7103 can be operated. Further, the remote control unit 7110 may be configured to be provided with a display unit 7107 for displaying information output from the remote control unit 7110. The operation of the television device 7100 can be performed by operation switches provided in the housing 7101 or by a separate remote control unit 7110. Channel and volume operations can be performed by operation keys 7109 provided on the remote control unit 7110, and the image displayed on the display unit 7103 can be operated. Further, the remote control unit 7110 may be configured to be provided with a display unit 7107 for displaying information output from the remote control unit 7110. The operation of the television device 7100 can be performed by operation switches provided in the housing 7101 or by a separate remote control unit 7110. Channel and volume operations can be performed by operation keys 7109 provided on the remote control unit 7110, and the image displayed on the display unit 7103 can be operated. Further, the remote control unit 7110 may be configured to be provided with a display unit 7107 for displaying information output from the remote control unit 7110. The operation of the television device 7100 can be performed by operation switches provided in the housing 7101 or by a separate remote control unit 7110. Channel and volume operations can be performed by operation keys 7109 provided on the remote control unit 7110, and the image displayed on the display unit 7103 can be operated. Further, the remote control unit 7110 may be configured to be provided with a display unit 7107 for displaying information output from the remote control unit 7110.

[0156] Note that the television device 7100 is configured to include a receiver, a modem, etc. The receiver can receive general TV broadcasts, and further, it can be connected to a wired or wireless network via a modem. Note that the television device 7100 is configured to include a receiver, a modem, etc. The receiver can receive general TV broadcasts, and further, it can be connected to a wired or wireless network via a modem. By connecting to a communication network, it is also possible to perform one-way (from the sender to the receiver) or two-way (between the sender and the receiver, or between the receivers, etc.) information communication. It is also possible to perform information communication in one direction (from the sender to the receiver) or two directions (between the sender and the receiver, or between the receivers, etc.).

[0157] Figure 7(B) is a computer, including a main body 7201, a housing 7202, a display unit 7203, a key board 7204, an external connection port 7205, a pointing device 7206, etc. Note that the computer can be manufactured by using the light-emitting device according to one aspect of the present invention for its display unit 7203. Also, the display panel 7203 may be a touch panel (input / output device) equipped with a touch sensor (input device ).

[0158] Figure 7(C) is a smartwatch, having a housing 7302, a display panel 7304, operation buttons 7311, 7312, connection terminals 7313, a band 7321, a buckle 7322, etc.

[0159] The display panel 7304 mounted on the housing 7302 that also serves as a bezel portion has a non-rectangular display area. The display panel 7304 can display an icon 7305 representing time, other icons 7306, etc. Also, the display unit 7304 may be a touch panel (input / output device) equipped with a touch sensor (input device).

[0160] Note that the smartwatch shown in Figure 7(C) can have various functions. For example , a function of displaying various information (still images, moving images, text images, etc.) on the display unit, a touch panel function, a function of displaying a calendar, date, or time, etc., a function of controlling processing by various software (program s), a wireless communication function, and a function of using the wireless communication function to communicate with various computers - A function of connecting to a network, and transmitting or receiving various data using a wireless communication function - A function of performing, and a function of reading a program or data recorded on a recording medium and displaying it on a display unit - It can have functions such as etc.

[0161] Also, inside the housing 7302, there can be a speaker, a sensor (for measuring force, displacement, position, speed, acceleration, angular velocity degree, rotational speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, electric pressure, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared rays), a microphone, etc. Note that the smartwatch can be manufactured by using a light-emitting device for its display panel 7304. It can be manufactured by using it for its display panel 7304.

[0162] FIG. 7(D) shows an example of a mobile phone (including a smartphone). The mobile phone 7 400 includes a display unit 7402, a microphone 7406, a speaker 7405, a camera 7407, an external connection unit 7404, operation buttons 7403, etc. on a housing 7401. Also, when a light-emitting element according to an aspect of the present invention is formed on a flexible substrate to manufacture a light-emitting device it can be applied to a display unit 7402 having a curved surface as shown in FIG. 7(D). It can be applied to a display unit 7402 having a curved surface as shown in FIG. 7(D).

[0163] The mobile phone 7400 shown in FIG. 7(D) can input information by touching the display unit 7402 with a finger or the like. Also, operations such as making a phone call or creating an email can be performed by touching the display unit 7402 with a finger or the like.

[0164] The screen of the display unit 7402 mainly has three modes. The first is a display mode mainly for displaying images and the second is an input mode mainly for inputting information such as characters. The third is the display This is a display + input mode that combines the display mode and the input mode.

[0165] For example, when making a call or composing an e-mail, the display unit 7402 is used to input characters. The main character input mode is to input characters displayed on the screen. It is preferable to display a keyboard or number buttons on most of the screen of the display portion 7402. It is nice.

[0166] In addition, a detection device such as a gyro sensor or an acceleration sensor is provided inside the mobile phone 7400. By this, the orientation of the mobile phone 7400 (vertical or horizontal) is determined, and the screen display of the display unit 7402 is can be made to switch automatically.

[0167] The screen mode can be changed by touching the display portion 7402 or by operating the housing 7401. The type of image displayed on the display unit 7402 can be changed by operating the button 7403. For example, the image signal to be displayed on the display unit may be changed by If the data is text data, the mode switches to input mode.

[0168] In the input mode, the optical sensor of the display unit 7402 detects a signal and displays If there is no input by touch operation of the part 7402 for a certain period of time, the screen mode is changed to the input mode. Alternatively, the display mode may be switched from the normal mode to the display mode.

[0169] The display portion 7402 can also function as an image sensor. By touching the palm or fingers of the user on the sensor 02 and capturing an image of the palm print or fingerprint, the user can be authenticated. In addition, a backlight that emits near-infrared light to the display unit or a sensing light source that emits near-infrared light If it is used, it is also possible to image finger veins, palm veins, etc.

[0170] Furthermore, as another configuration of a mobile phone (including a smartphone), it can also be applied to a mobile phone having a structure such as that shown in FIG. 7(D'-1) or FIG. 7(D'-2).

[0171] In addition, when having a structure such as that shown in FIG. 7(D'-1) or FIG. 7(D'-2), character information, image information, etc. can be displayed not only on the first surfaces 7501(1) and 7501 (2) of the housings 7500(1) and 7500(2), but also on the second surfaces 7502(1) and 7502(2). By having such a structure, while the mobile phone is stored in the chest pocket, the user can easily check the character information, image information, etc. displayed on the second surfaces 7502(1) and 7502(2).

[0172] Also, FIGS. 8(A) to (C) show a foldable portable information terminal 9310. FIG. 8(A ) shows the portable information terminal 9310 in the unfolded state. FIG. 8(B) shows the portable information terminal 9310 in a state where it is changing from one of the unfolded state or the folded state to the other. FIG. 8( C) shows the portable information terminal 9310 in the folded state. The portable information terminal 9310 has excellent portability in the folded state and excellent display integrity due to a seamless and wide display area in the unfolded state. The display panel 9311 is supported by three housings 9315 connected by a hinge 9313. Note that the display panel 9311 may be a touch panel (input / output device) equipped with a touch sensor (input device). Also, the display panel 9311 is connected via the hinge 9313.

[0173] By bending between the two housings 9315, the portable information terminal 9310 can be reversibly deformed from the unfolded state to the folded state. The light-emitting device according to one aspect of the present invention can be used for the display panel 9311. The display area on the display panel 9311 is the display area located on the side surface of the portable information terminal 9310 in the folded state. In the display area, information icons, frequently used apps, shortcuts to programs, etc. can be displayed, and information can be smoothly confirmed and apps can be smoothly launched.

[0174] As described above, an electronic device can be obtained by applying the light-emitting device according to one aspect of the present invention. Note that the applicable electronic devices are not limited to those shown in this portable embodiment, and can be applied to electronic devices in all fields.

[0175] Note that the configuration shown in this embodiment can be appropriately combined with the configuration shown in other embodiments and used.

[0176] (Embodiment 7) In this embodiment, an example of a lighting device to which the light-emitting device according to one aspect of the present invention is applied will be described with reference to FIG. 9.

[0177] FIG. 9 shows an example in which the light-emitting device is used as an indoor lighting device 8001. Note that since the light-emitting device can also be increased in area, a large-area lighting device can also be formed. In addition, by using a housing having a curved surface, a lighting device 8002 having a housing, a cover, or a support base and having a curved light-emitting area can also be formed. The light-emitting element included in the light-emitting device shown in this embodiment is in a thin film shape, and the degree of freedom in the design of the housing is high. Therefore, various designs are elaborated. element included in the light-emitting device shown in this embodiment is in a thin film shape, and the degree of freedom in the design of the housing is high. Therefore, various designs are elaborated. It is possible to form a lighting device. Further, a large lighting device 8003 may be provided on the interior wall surface. It may be.

[0178] Also, by using the light-emitting device on the surface of the table, a lighting device 8004 having a function as a table can be obtained. In addition, by using the light-emitting device for a part of other furniture, a lighting device having a function as furniture can be obtained. It can be made into the lighting device 8004. That is, it can be made into a lighting device having a function as furniture.

[0179] As described above, various lighting devices to which the light-emitting device is applied can be obtained. These lighting devices are included in one aspect of the present invention. It shall be.

[0180] Also, the configuration shown in this embodiment can be used in appropriate combination with the configuration shown in other embodiments. It can be.

Example

[0181] ≪Synthesis Example 1≫ In this example, as a synthesis method which is one aspect of the present invention, the synthesis method of 2-{4-[3-(N-phenyl -9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzo [f,h]quinoxaline (abbreviation: 2PCCzPDBq) (structural formula (100)) will be described. The structure of 2PCCzPDBq is shown below. That is, the structure of 2PCCzPDBq is shown below.

[0182]

Chemical formula

[0183] <Synthesis of 2PCCzPDBq> First, 1.0 g (2.8 mmol) of 2-(4-chlorophenyl)dibenzo[f,h]quinoxaline, 3-(9-phenyl-9H-carbazol-3-yl)-9H-carbazole ​1.1 g (2.8 mmol), 0.54 g (5.6 mmol) of sodium tert-butoxide, and 23 mg (0.10 mmol) of 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (S-Phos) were placed in a 200 mL three-necked flask and mixed, and the flask was purged with nitrogen. To this mixture was added 14 mL of mesitylene, and the inside of the flask was evacuated and degassed by stirring. Next, 16 mg (0.028 mmol) of bis(dibenzylideneacetone)palladium(0) (abbreviation: Pd(dba)) was added to this mixture. The mixture was stirred at 150 °C for 5 hours under a nitrogen stream, and a solid precipitated. The precipitated solid was collected by suction filtration.

[0184] The collected solid was dissolved in about 400 mL of heated toluene, and this solution was suction filtered through a Celite and alumina laminate. 2 The solid obtained by concentrating the resulting filtrate was recrystallized from toluene to obtain 1.6 g of the target yellow powder in a yield of 80%. 1.4 g of the obtained yellow powdery solid of the target product was sublimation purified by the train sublimation method. The sublimation purification conditions were as follows: pressure 3.8 Pa, flowing argon gas at a flow rate of 10 mL / min, and heating at 380 °C. After sublimation purification, 1.1 g of the yellow glassy solid of 2PCCzPDBq was obtained in a yield of 79%. The synthetic scheme for this step is shown in the following (a-1).

[0185]

[0186]

[0186]

Chemical formula

[0187] Analysis of the yellow powdery solid obtained in the above step by nuclear magnetic resonance spectroscopy (1H-NMR) 1 ​​The results are shown below. Also, 1 The 1H-NMR charts are shown in FIGS. 10(A) and (B). Note that FIG. 10(B) is an enlarged view of FIG. 10(A) with the horizontal axis (δ) ranging from 7.0 (ppm) to 10 (ppm). From this, it was found that 2PCCzPDBq (structural formula (100)) was obtained in the above step.

[0188] δ = 7.32 (t, J = 5.7 Hz, 1H), 7.37 (t, J = 8.0 Hz, 1H), 7.43 - 7.53 (m, 5H), 7.58 - 7.66 (m, 6H), 7.72 - 7.8 9 (m, 8H), 8.25 (d, J = 7.4 Hz, 1H), 8.30 (d, J = 8.1 H z, 1H), 8.44 (d, J = 7.5 Hz, 1H), 8.50 (d, J = 5.4 Hz, 2H), 8.64 - 8.67 (m, 3H), 9.25 (d, J = 8.0 Hz, 1H), 9 .37 (d, J = 6.3 Hz, 1H), 9.47 (s, 1H).

[0189] Next, the absorption spectrum and emission spectrum of a toluene solution of 2PCCzPDBq are shown in FIG. 11 , and the absorption spectrum and emission spectrum of the thin film are shown in FIG. 12. For the measurement of the spectra, a UV-visible spectrophotometer (manufactured by JASCO Corporation, model V550) was used. The spectrum of the toluene solution of toluene was measured by putting the toluene solution of 2PCCzPDBq in a quartz cell. Also, the spectrum of the thin film was measured by depositing 2PCCzPDBq on a quartz substrate to prepare a sample. Note that the absorption spectrum of the toluene solution is shown as the absorption spectrum obtained by subtracting the absorption spectrum measured with only toluene in the quartz cell, and the absorption spectrum of the thin film is shown as the absorption spectrum obtained by subtracting the absorption spectrum of the quartz substrate. spectrum. was shown.

[0190] As shown in Fig. 11, the toluene solution of 2PCCzPDBq exhibits absorption peaks around 305 nm and 385 nm, and the peak of the emission wavelength is 450 nm (excitation wavelength 305 nm). Also, as shown in Fig. 12, the thin film of 2PCCzPDBq exhibits absorption peaks around 209 nm, 258 nm, 307 nm, 336 nm, and 396 nm, and the peak of the emission wavelength is 502 nm (excitation wavelength 396 nm).

Example

[0191] ≪Synthesis Example 2≫ In this example, as a synthesis method according to one aspect of the present invention, the synthesis method of 2-{3-[3-(N-phenyl- 9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenz zo[f,h]quinoxaline (abbreviated as 2mPCCzPDBq) (structural formula (101)) will be described. The structure of 2mPCCzPDBq is shown below.

[0192]

Chemical formula

[0193] <Synthesis of 2mPCCzPDBq> First, 1.7 g (5.0 mmol) of 2-(3-chlorophenyl)dibenz[f,h]quinoxaline, 2.0 g (5.0 mmol) of 3-(9-phenyl-9H-carbazol-3-yl)-9H-carbazole, 0.96 g (10 mmol) of sodium tert-butoxide, and 41 mg (0.10 mmol) of 2-dicyclohexylphosphino-2’,6’-dimethoxybiphenyl (S-P hos) were placed in a 200 mL three-necked flask and mixed, and the flask was purged with nitrogen. 25 mL of mesitylene was added to this mixture, and the inside of the flask was placed under reduced pressure and degassed by stirring. ​​​​​

[0194] Next, 29 mg (0.050 mmol) of bis(dibenzylideneacetone)palladium(0) (abbreviation: Pd( dba) 2 ) was added to this mixture. When this mixture was stirred at 15 0 °C for 5 hours, a solid precipitated. The precipitated solid was collected by suction filtration . The collected solid was dissolved in about 400 mL of heated toluene, and this solution was suction filtered through a laminate of celite and aluminum sodium. The solid obtained by concentrating the resulting filtrate was recrystallized from toluene to obtain 2.8 g of the target yellow powder with a yield of 79%.

[0195] 2.2 g of the obtained yellow powdery solid of the target product was sublimation-purified by the train sublimation method . The sublimation purification conditions were carried out by heating at 360 °C while flowing argon gas at a flow rate of 10 mL / min under a pressure of 2.5 Pa . After sublimation purification, 1.2 g of the yellow glassy solid of 2mPCCzPDBq was obtained with a recovery rate of 55%. The synthesis scheme of this step is shown in the following (b-1) . .

[0196]

Chemical formula

[0197] Analysis of the yellow powdery solid obtained in the above step by nuclear magnetic resonance spectroscopy 1 (1H-NMR) results are shown below. Also 1 the 1H-NMR chart is shown in FIGS. 13(A) and (B). Note that FIG 13(B) is an enlarged view of FIG. 13(A) with the horizontal axis (δ) in the range of 7.0 (ppm) to 10 (ppm) . From this, in the above step, 2-{3-[3-( N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl 2,9-Dinaphtho[f,h]quinoxaline (abbreviation: 2mPCCzPDBq) (structural formula (10 1)) was found to be obtained.

[0198] 1 H NMR (CDCl 3 , 500 MHz): δ (ppm) = 7.31 - 7.54 (m, 7H), 7.58 - 7.67 (m, 6H), 7.73 - 7.90 (m, 8H), 8.25 (d, J = 8.0 Hz, 1H), 8.30 (d, J = 8.1 Hz, 1H), 8.45 (d , J = 6.3 Hz, 1H), 8.49 (d, J = 3.7 Hz, 2H), 8.65 - 8.6 8 (m, 3H), 9.25 (d, J = 2.0 Hz, 1H), 9.37 (d, J = 6.9H z, 1H), 9.48 (s, 1H).

[0199] Next, the absorption spectrum and emission spectrum of the toluene solution of 2mPCCzPDBq are shown in Fig. 1 4, and the absorption spectrum and emission spectrum of the thin film are shown in Fig. 15. For the measurement of the spectrum, an ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, model V550) was used. The spectrum of the toluene solution was measured by putting the toluene solution of 2mPCCzPDBq in a quartz cell. Also, the spectrum of the thin film was measured by depositing 2mPCCzPDBq on a quartz substrate to prepare a sample. Note that the absorption spectrum of the toluene solution was measured by subtracting the absorption spectrum measured with only toluene in the quartz cell and the absorption spectrum of the thin film was illustrated by subtracting the absorption spectrum of the quartz substrate .

[0200] From Fig. 14, the toluene solution of 2mPCCzPDBq had absorption peaks around 305 nm and 374 nm, and the peak of the emission wavelength was 480 nm (excitation wavelength 305 nm). Also , from Figure 15, the thin film of 2mPCCzPDBq has absorption peaks at around 208 nm, 257 nm, 308 nm, 36 1 nm, and 379 nm, and the peak of the emission wavelength is 515 nm (excitation wavelength 380 nm).

Example

[0201] ≪Synthesis Example 3≫ In this example, as a synthesis method which is one aspect of the present invention, 2-{4-[2-(N-phenyl -9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzo zo[f,h]quinoxaline (abbreviation: 2PCCzPDBq-02) (structural formula (102)) will be described. The structure of 2PCCzPDBq-02 is shown below.

[0202]

Chemical formula

[0203] <Synthesis of 2PCCzPDBq-02> First, 1.4 g (4.2 mmol) of 2-(4-chlorophenyl)dibenzo[f,h]quinoxaline, 1.7 g (4.2 mmol) of 2-(9-phenyl-9H-carbazol-3-yl)-9H-carbazole , 0.81 g (8.4 mmol) of sodium tert-butoxide, and 34 mg (0.10 mmol) of 2-dicyclohexylphosphino-2’,6’-dimethoxybiphenyl (S- Phos) are placed in a 200 mL three-necked flask and mixed, and the flask is purged with nitrogen. 21 mL of mesitylene is added to this mixture, and the inside of the flask is under reduced pressure and degassed by stirring. Next, to this mixture, bis(dibenzylideneacetone)palladium(0) (abbreviation: Pd( 0)) is added...

[0204] and... dba) 2 ) 24 mg (0.042 mmol) was added. The mixture was stirred at 15 0 °C for 5 hours, and a solid precipitated. The precipitated solid was collected by suction filtration . The collected solid was dissolved in about 400 mL of hot toluene, and this solution was filtered by suction through a laminate of celite and aluminum sodium. The solid obtained by concentrating the resulting filtrate was recrystallized from toluene , and 2.5 g of the yellow powder of the target product was obtained in a yield of 84%.

[0205] 2.0 g of the obtained yellow powdery solid of the target product was purified by sublimation using the train sublimation method . The sublimation purification conditions were carried out by heating at 390 °C while flowing argon gas at a flow rate of 10 mL / min under a pressure of 3.7 Pa . After sublimation purification, 1.7 g of the yellow glassy solid of 2PCCzPDBq-02 was obtained in a recovery rate of 85%. The synthesis scheme of this step is shown in the following (c-1) . as shown.

[0206]

Chemical formula

[0207] Analysis of the yellow powdery solid obtained in the above step by nuclear magnetic resonance spectroscopy ( 1 1H-NMR) results are shown below. Also, 1 the 1H-NMR chart is shown in FIGS. 16(A) and (B). Note that FIG. 16(B) is an enlarged view of FIG. 16(A) with the horizontal axis (δ) in the range from 7.0 (ppm) to 10 (ppm) . From this, in the above step, 2-{4-[2-( N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzof [h] quinoxaline (abbreviation: 2PCCzPDBq-02) (structural formula ( ) It was found that [[102)) was obtained.

[0208] δ = 7.25 - 7.48 (m, 7H), 7.71 - 7.75 (m, 2H), 7.71 - 7 .75 (m, 5H), 7.91 (d, J = 8.6 Hz, 2H), 8.21 (d, J = 7. 4 Hz, 1H), 8.26 (d, J = 8.0 Hz, 2H), 8.42 (sd, J = 1.7 Hz, 2H), 8.63 - 8.69 (m, 4H), 9.27 (d, J = 8.0 Hz, 1H ), 9.46 (d, J = 6.3 Hz, 1H), 9.51 (s, 1H).

[0209] Next, the absorption spectrum and emission spectrum of the toluene solution of 2PCCzPDBq - 02 are shown in Fig. 17 for the thin film absorption spectrum and emission spectrum in Fig. 18. The spectrum measurement was performed using an ultraviolet - visible spectrophotometer (manufactured by JASCO Corporation, model V550). The spectrum of the toluene solution was measured by putting the toluene solution of 2PCCzPDBq - 02 into a quartz cell. Also, the spectrum of the thin film was obtained by depositing 2PCCzPDBq - 02 on a quartz substrate to prepare a sample. Note that the absorption spectrum of the toluene solution is shown as the absorption spectrum obtained by subtracting the absorption spectrum measured with only toluene in the quartz cell, and the absorption spectrum of the thin film is shown as the absorption spectrum obtained by subtracting the absorption spectrum of the quartz substrate. From Fig. 17, the toluene solution of 2PCCzPDBq - 02 shows absorption peaks around 323 nm and 381 nm, and the peak of the emission wavelength is 421 nm (excitation wavelength 320 nm).

[0210] From Fig. 18, the thin film of 2PCCzPDBq - 02 shows absorption peaks around 209 nm, 257 nm, 311 n m, 326 nm, 351 nm, and 389 nm, and the peak of the emission wavelength is ​​K was 473 nm (excitation wavelength: 396 nm).

Example

[0211] ≪Synthesis Example 4≫ In this example, 2-{3-[2-(N-phenyl-9H-carbazol -3-yl)-9H-carbazol-9-yl]phenyl}dibenzof[h]quin xaline (abbreviation: 2mPCCzPDBq-02) (structural formula (103)), a synthesis method thereof will be described. The structure of 2mPCCzPDBq-02 is shown below.

[0212]

Chemical formula

[0213] <Synthesis of 2mPCCzPDBq-02> First, 1.7 g (5.0 mmol) of 2-(3-chlorophenyl)dibenzof[h]quinoxaline, 2.0 g (5.0 mmol) of 2-(9-phenyl-9H-carbazol-3-yl)-9H-carbazole, 0.96 g (10 mmol) of sodium tert-butoxide, and 41 mg (0.10 mmol) of 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (S-P hos) were placed in a 200 mL three-necked flask and mixed, and the flask was purged with nitrogen. 25 mL of mesitylene was added to this mixture, and the inside of the flask was evacuated and degassed by stirring.

[0214] Next, 29 mg (0.050 mmol) of bis(dibenzylideneacetone)palladium(0) (abbreviation: Pd( dba) 2 ) was added to this mixture. This mixture was stirred at 15 0 °C for 4 hours under a nitrogen stream, and a solid precipitated. The precipitated solid was collected by suction filtration 2 ) and the solid thus precipitated was collected by suction filtration. The recovered solid was dissolved in about 400 mL of heated toluene, and this solution was suction filtered through a layer of Celite and alumina and Florisil. The solid obtained by concentrating the resulting filtrate was recrystallized from toluene to obtain 3.1 g of the target white powder in a yield of 87%.

[0215] 3.0 g of the obtained white powdery solid of the target product was sublimation purified by the train sublimation method. The sublimation purification conditions were as follows: pressure 10 Pa, flowing argon gas at a flow rate of 5.0 mL / min, and heating at 360 °C. After sublimation purification, 2.0 g of the yellow glassy solid of 2mPCCzPDBq-02 was obtained at a recovery rate of 65%. The synthesis scheme of this step is shown in the following (d-1).

[0216]

Chemical formula

[0217] Analysis of the white powdery solid obtained in the above step by nuclear magnetic resonance spectroscopy ( 1 1H-NMR) is shown below. Also, the 1 1H-NMR chart is shown in FIGS. 19(A) and (B). Note that FIG. 19(B) is an enlarged view of FIG. 19(A) with the horizontal axis (δ) in the range of 7.0 (ppm) to 10 (ppm). From this, it was found that 2mPCCzPDB q-02 (structural formula (103)) was obtained in the above step.

[0218] 1 1H NMR (DMSO-d 6 , 500 MHz): δ (ppm) = 7.17 (t, J1 = 7.5 Hz, 1H), 7.31 - 7.39 (m, 4H), 7.47 - 7.52 (m, 2H ​​​​​​​), 7.56 - 7.57 (m, 3H), 7.63 - 7.66 (m, 3H), 7.75 - 7 .92 (m, 7H), 7.98 (t, J1 = 2.5Hz, 1H), 8.19 (d, J1 = 7.5Hz, 1H), 8.30 (d, J1 = 7.5Hz, 1H), 8.37 (d, J1 = 8.0Hz, 1H), 8.54 (sd, J1 = 1.5Hz, 1H), 8.62 (d, J1 = 8.0Hz, 1H), 8.79 - 8.82 (m, 3H), 9.19 (d, J1 = 8.0 Hz, 1H), 9.25 (d, J1 = 9.0Hz, 1H), 9.75 (s, 1H).

[0219] Next, the absorption spectrum and emission spectrum of the toluene solution of 2mPCCzPDBq - 02 are shown in Figure 20, and the absorption spectrum and emission spectrum of the thin film are shown in Figure 21. For the measurement of the spectra, a UV - visible spectrophotometer (manufactured by JASCO Corporation, model V550) was used. The spectrum of the toluene solution was measured by putting the toluene solution of 2mPCCzPDBq - 02 in a quartz cell. Also, the spectrum of the thin film was measured by depositing 2mPCCzPDBq - 02 on a quartz substrate to prepare a sample and then measuring it. Note that the absorption spectrum of the toluene solution is shown as the absorption spectrum obtained by subtracting the absorption spectrum measured with toluene only in the quartz cell, and the absorption spectrum of the thin film is shown as the absorption spectrum obtained by subtracting the absorption spectrum of the quartz substrate . From Figure 20, the toluene solution of 2mPCCzPDBq - 02 shows absorption peaks near 281 nm, 305 nm, 3 19 nm, and 374 nm, and the peak wavelengths of the emission are 389 nm and 410 nm. Also, from Figure 21, the thin film of 2mPCCzPDBq - 02 shows absorption peaks near 209

[0220] nm, 257 nm, 309 nm, 327 nm, 354 nm, and 386 nm. nm, 257 nm, 309 nm, 327 nm, 354 nm, and 386 nm near the absorption peaks ​​A peak was observed in the emission wavelength at 484 nm (excitation wavelength 381 nm). EXAMPLES

[0221] In this example, a development process was carried out using a dibenzo[f,h]quinoxaline derivative which is one embodiment of the present invention. The optical element 1, the light-emitting element 2, and the comparative light-emitting element 3 were fabricated. The details will be explained with reference to Fig. 22. The chemical formulas of the materials used in this example are shown below.

[0222] [ka]

[0223] [ka]

[0224] <Fabrication of Light-Emitting Element 1, Light-Emitting Element 2, and Comparative Light-Emitting Element 3> First, indium tin oxide containing silicon oxide (ITSO) is deposited on a glass substrate 1100. A film was formed by a sputtering method to form a first electrode 1101 that functions as an anode. The film thickness was 110 nm and the electrode area was 2 mm × 2 mm.

[0225] Next, in order to form the light-emitting element 1, the light-emitting element 2, and the comparative light-emitting element 3 on the substrate 1100, As a pretreatment, the substrate surface was washed with water, baked at 200°C for 1 hour, and then UV ozone treatment was performed. This was done for 370 seconds.

[0226] Then, 10 -4 The substrate is placed in a vacuum deposition apparatus whose inside has been reduced in pressure to about Pa, and vacuum deposition is performed. After vacuum baking at 170° C. for 30 minutes in the heating chamber of the device, the substrate 1100 is It was left to cool for about 0 minutes.

[0227] Next, the substrate 1100 was fixed to a holder provided in a vacuum deposition apparatus so that the surface on which the first electrode 1101 was formed faced downward. In this embodiment, a hole injection layer 1111, a hole transport layer 1112, a light-emitting layer 1113, an electron transport layer 1114, and an electron injection layer 1115 that constitute the EL layer 1102 will be described for the case where they are sequentially formed by a vacuum deposition method. 02 will be described for the case where they are sequentially formed by a vacuum deposition method. 1114, and an electron injection layer 1115 that constitute the EL layer 1102 will be described for the case where they are sequentially formed by a vacuum deposition method.

[0228] After reducing the pressure inside the vacuum deposition apparatus to 10 -4 Pa, 1,3,5-tri(dibenzothiophen- 4-yl)-benzene (abbreviation: DBT3P-II) and molybdenum oxide were co-evaporated so that the ratio of DBT3P- II:molybdenum oxide was 4:2 (mass ratio), thereby forming a hole injection layer 1111 on the first electrode 1101. The film thickness was set to 20 nm. Note that co-evaporation is a deposition method in which a plurality of different substances are simultaneously evaporated from different evaporation sources. is a deposition method in which a plurality of different substances are simultaneously evaporated from different evaporation sources.

[0229] Next, 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP) was deposited to a thickness of 20 nm to form a hole transport layer 1112. .

[0230] Next, a light-emitting layer 1113 was formed on the hole transport layer 1112. In the case of the light-emitting element 1, 2-{ 3-[2-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9 -yl]phenyl}dibenzof[f,h]quinoxaline (abbreviation: 2mPCCzPDBq-0 2 (structural formula (103))), N-(1,1'-biphenyl-4-yl)-N-[4-(9 -phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-f luorene-2-amine (abbreviation: PCBBiF), (acetylacetonato)bis(6-te (rt-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tB uppm) 2 (acac)]) was co-evaporated with 2mPCCzPDBq-02:PCBBiF:[Ir (tBuppm) 2 (acac)] = 0.7:0.3:0.05 (mass ratio) to form a layer with a thickness of 20 nm. Then, 2mPCCzPDBq-02:PCBBiF: Ir(tBuppm) (acac)] = 0.8:0.2:0.05 (mass ratio) was co-evaporated in the same way to form a light-emitting layer 1113 with a laminated structure having a thickness of 4 2 (acac)] = 0.8:0.2:0.05 (mass ratio) and formed with a thickness of 40 nm. By forming it with a thickness of 0 nm. A light-emitting layer 1113 having a laminated structure was formed with a thickness of 40 nm.

[0231] In the case of the light-emitting element 2, 2-{3-[3-(N-phenyl-9H-carbazol-3-yl )-9H-carbazol-9-yl]phenyl}dibenzof[h]quinoxaline (abbreviation : 2mPCCzPDBq (structural formula (101))), PCBBiF, [Ir(tBuppm ) 2 (acac)] was co-evaporated with 2mPCCzPDBq:PCBBiF:[Ir(tBuppm) 2 (acac)] = 0.7:0.3:0.05 (mass ratio) to form a layer with a thickness of 20 nm. Then, 2mPCCzPDBq:PCBBiF:[Ir(tBuppm 2 (acac)] = 0.8:0.2:0.05 (mass ratio) was co-evaporated in the same way to form a light-emitting layer 1113 with a laminated structure having a thickness of 20 nm. (acac)] = 0.8:0.2:0.05 (mass ratio) and formed with a thickness of 20 nm. By forming it with a thickness of 40 nm, a light-emitting layer 1113 having a laminated structure was formed with a thickness of 40 nm.

[0232] Also, in the case of the comparative light-emitting element 3, 2-[3'-(dibenzothiophen-4-yl)biphe Nil-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II ), PCBBiF, [Ir(tBuppm) 2 (acac)] were co-evaporated such that 2mDBTBPDBq -II:PCBBiF:[Ir(tBuppm) 2 (acac)] = 0.7:0.3:0 .05 (mass ratio), and after forming a film with a thickness of 20 nm, 2mDBTBPD Bq-II:PCBBiF:[Ir(tBuppm) 2 (acac)] = 0.8:0.2 :0.05 (mass ratio) was co-evaporated and formed with a film thickness of 20 nm to form a light-emitting layer 1113 having a stacked structure with a thickness of 40 nm.

[0233] Next, in the case of the light-emitting device 1, after evaporating 2mPCCzPDBq-02 at 20 nm on the light-emitting layer 1113, bathophenanthroline (abbreviation: Bphen) was evaporated at 10 nm to form an electron transport layer 1114. Also, in the case of the light-emitting device 2, after evaporating 2m PCCzPDBq at 20 nm on the light-emitting layer 1113, bathophenanthroline (abbreviation: Bphen) was evaporated at 10 nm to form an electron transport layer 1114. Also, in the case of the comparative light-emitting device 3, after evaporating 2mDBTBPDBq-II at 20 nm on the light-emitting layer 1113, batho phenanthroline (abbreviation: Bphen) was evaporated at 10 nm to form an electron transport layer 111 4.

[0234] Furthermore, on the electron transport layer 1114, lithium fluoride was evaporated at 1 nm to form an electron injection layer 1115.

[0235] Finally, aluminum was evaporated on the electron injection layer 1115 to a film thickness of 200 nm, A second electrode 1103 serving as a cathode was formed, and the light-emitting element 1, the light-emitting element 2, and the comparative light-emitting element were In the above-mentioned deposition process, the deposition was all performed by resistance heating.

[0236] The device structures of the thus obtained light-emitting element 1, light-emitting element 2, and comparative light-emitting element 3 are shown in Table 1. show.

[0237] [Table 1]

[0238] The fabricated light-emitting element 1, light-emitting element 2, and comparative light-emitting element 3 were placed in a container so as not to be exposed to the air. The device was sealed in a glove box with a nitrogen atmosphere (specifically, the device was sealed in a nitrogen atmosphere). The specimen was then coated with a coating of adhesive, UV-treated, and heat-treated at 80°C for 1 hour.

[0239] <Operation characteristics of light-emitting element 1, light-emitting element 2, and comparative light-emitting element 3> The operating characteristics of the fabricated light-emitting element 1, light-emitting element 2, and comparative light-emitting element 3 were measured. The measurements were carried out at room temperature (atmosphere maintained at 25°C). The results are shown in Figures 23 to 26. show.

[0240] Also, 1000cd / m 2 Light-emitting element 1, light-emitting element 2, and comparative light-emitting element 3 in the vicinity The main initial characteristic values ​​are shown in Table 2 below.

[0241] [Table 2]

[0242] In addition, the light-emitting element 1, the light-emitting element 2, and the comparative light-emitting element 3 were each subjected to a current of 2.5 mA / cm 2 Current density of The emission spectra when current is passed are shown in Fig. 27. As shown in Fig. 27, the light-emitting element 1, the light-emitting element 2, and the comparative light-emitting element 3 all have spectra with a peak near 546 nm 2 derived from [[Ir(tBuppm)(acac)]].

[0243] In addition, the results of the reliability tests for the light-emitting element 1, the light-emitting element 2, and the comparative light-emitting element 3 are shown in Fig. 28(A). In Fig. 28(A), the vertical axis represents the normalized luminance (%) with the initial luminance set to 100%, and the horizontal axis represents the driving time (h) of the element. Note that in the reliability test, the initial luminance was set to 5000 cd / m 2 , and the light-emitting element 1, the light-emitting element 2, and the comparative light-emitting element 3 were driven under the condition of a constant current density.

[0244] As a result, it was found that the light-emitting element 1 using 2mPCCzPDBq-02 and the light-emitting element 2 using 2mPCCzPDBq are long-life light-emitting elements with higher reliability than the comparative light-emitting element 3 using 2mDBTBPDBq-II.

[0245] In addition, the results of measuring the amount of voltage change during the reliability test are shown in Fig. 28(B). The vertical axis represents the voltage change amount (V), and the horizontal axis represents the driving time (h) of the element. As can be seen from this result, the light-emitting element 1 and the light-emitting element 2 have a smaller voltage increase when driven at a constant current than the comparative light-emitting element 3. For example, looking at the amount of voltage increase after driving for about 500 hours, the comparative light-emitting element 3 is about 0.08 V, while the light-emitting element 1 is about 0.05 V and the light-emitting element 2 is about 0.0 2 V. That is, compared with the comparative light-emitting element 3, the amount of voltage increase of the light-emitting element 1 is about half, and the The voltage increase amount of the element 2 is suppressed to about one-fourth, indicating a remarkable effect.

[0246] In addition, 2mPCCzPDBq-02, 2mPCCzPDBq, 2mDBTBPDBq-I I all form an exciplex with PCBBiF (the mixed films of these dibenzoquinoxaline compounds and PCBBiF all show yellow-green emission with a longer wavelength than each dibenzoquinoxaline compound single film or PCBBiF single film). BiF single film). Also, the HOMO levels of 2mPCCzPDBq-02, 2mPCCzPDBq, 2mDBTBPDBq-II, and PCBBiF are -5.69 eV, -5.63 eV, -6.22 eV, and -5.36 eV respectively. The HOMO level was calculated from cyclic voltammetry (CV) measurements.

[0247] From the measurement results of the HOMO level, ΔE in the light-emitting layer of each light-emitting element was calculated. HOMO The results are summarized in Table 3.

[0248]

Table 3

[0249] HOMO It can be seen from this result that it is important that ΔE is 0.4 eV or less, more preferably 0.3 eV or less.

[0250] The HOMO level of the third organic compound used in the hole transport layer is -5.51 eV. Therefore, the HOMO level of the third organic compound used in the hole transport layer is lower than the HOMO level of PCBBiF, which is the second organic compound. Also, the second organic compound It can be seen that it is located between the HOMO level of PCBBiF and the HOMO level of the first organic compound (2mPCCzPDBq-02 or 2mPCCzPDBq). This is important from the perspective of injecting holes not only into the second organic compound but also into a part of the first organic compound . .

Example

[0251] In this example, a light-emitting device 4 using a dibenzo[f,h]quinoxaline derivative, which is one aspect of the present invention, was fabricated. The configuration of the light-emitting device will be described with reference to FIG. 22 shown in Example 5. The chemical formulas of the materials used in this example are shown below. Also, the chemical formulas of the materials used in this example are shown below. .

[0252]

Chemical formula

[0253] ≪Fabrication of light-emitting device 4≫ First, indium tin oxide (ITSO) containing silicon oxide was formed on a glass substrate 1100 by a sputtering method to form a first electrode 1101 that functions as an anode. The film thickness was 110 nm, and the electrode area was 2 mm × 2 mm. . The film thickness was 110 nm, and the electrode area was 2 mm × 2 mm. .

[0254] Next, as a pretreatment for forming the light-emitting device 4 on the substrate 1100, the surface of the substrate was washed with water, baked at 200 °C for 1 hour, and then subjected to UV ozone treatment for 370 seconds. .

[0255] Thereafter, the substrate was introduced into a vacuum evaporation apparatus whose internal pressure was reduced to about 10 -4 Pa, and vacuum baking was performed at 170 °C for 30 minutes in the heating chamber of the vacuum evaporation apparatus. Then, the substrate 1100 was allowed to cool for about 3 0 minutes. .

[0256] Next, the substrate 1100 was fixed to a holder provided in a vacuum deposition apparatus so that the surface on which the first electrode 1101 was formed faced downward. In this embodiment, the case where the hole injection layer 1111, the hole transport layer 1112, the light-emitting layer 1113, the electron transport layer 1114, and the electron injection layer 1115 constituting the EL layer 1102 were sequentially formed by a vacuum deposition method will be described. 02 will be described. After reducing the pressure inside the vacuum deposition apparatus to 10

[0257] Pa, 1,3,5-tri(dibenzothiophen- -4 4-yl)benzene (abbreviation: DBT3P-II) and molybdenum oxide were co-evaporated so that the ratio of DBT3P-I I: molybdenum oxide was 4:2 (mass ratio), thereby forming a hole injection layer 1111 on the first electrode 1101. The film thickness was set to 20 nm. Note that co-evaporation is a deposition method in which a plurality of different substances are simultaneously evaporated from different evaporation sources.

[0258] Next, 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP) was deposited to a thickness of 20 nm to form a hole transport layer 1112.

[0259] Next, a light-emitting layer 1113 was formed on the hole transport layer 1112. 2-{4-[2-(N-phenyl- 9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}di benzo[f,h]quinoxaline (abbreviation: 2PCCzPDBq-02 (structural formula (102)) ), N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol- 3-yl)phenyl]-9,9-dimethyl-9H-fluorene-2-amine ( abbreviation: PCBBiF), (acetylacetonato)bis(4,6-diphenylpyrimidinato )Iridium(III) (abbreviation: [Ir(dppm) 2 (acac)]) was co-evaporated with 2PCCz PDBq-02:PCBBiF:[Ir(dppm) 2 (acac)] = 0.7:0.3 :0.05 (mass ratio) to form a film with a thickness of 20 nm. After that, 2PCCzP DBq-02:PCBBiF:[Ir(dppm) 2 (acac)] = 0.8:0.2: 0.05 (mass ratio) was co-evaporated and formed with a thickness of 20 nm to form a stacked structure The light-emitting layer 1113 having a thickness of 40 nm was formed.

[0260] Next, 2PCCzPDBq-02 was evaporated onto the light-emitting layer 1113 to a thickness of 20 nm, and then bathophen antroline (abbreviation: Bphen) was evaporated to a thickness of 10 nm to form an electron transport layer 1114.

[0261] Furthermore, lithium fluoride was evaporated onto the electron transport layer 1114 to a thickness of 1 nm to form an electron injection layer 1115.

[0262] Finally, aluminum was evaporated onto the electron injection layer 1115 to a thickness of 200 nm, and the second electrode 1103 serving as the cathode was formed to obtain the light-emitting device 4. In the above evaporation process all evaporation was carried out using the resistance heating method.

[0263] The device structure of the light-emitting device 4 obtained as above is shown in Table 4.

[0264]

Table 4

[0265] Also, the fabricated light-emitting device 4 was placed in a glove box under a nitrogen atmosphere so as not to be exposed to the air sealed (specifically, applying a sealing material around the element, UV treatment, and heat treatment at 80 °C for 1 hour). for 1 hour).

[0266] ≪Operating characteristics of the light-emitting element 4≫ The operating characteristics of the fabricated light-emitting element 4 were measured. The measurement was carried out at room temperature (atmosphere maintained at 25 °C). The results are shown in FIGS. 29 to 32.

[0267] Also, the main initial characteristic values of the light-emitting element 4 near 1000 cd / m² are shown in Table 5 below 2 .

[0268]

Table 5

[0269] Also, the emission spectrum when a current was passed through the light-emitting element 4 at a current density of 2.5 mA / cm² is shown in FIG. 33. As shown in FIG. 33, the light-emitting element 4 showed a spectrum having a peak near 581 nm derived from 2 [Ir(dppm) (acac)] 2 .

[0270] Also, the results of the reliability test for the light-emitting element 4 are shown in FIG. 34(A). In FIG. 34(A), the vertical axis represents the normalized luminance (%) when the initial luminance is 100%, and the horizontal axis represents the driving time (h) of the element. The reliability test was set with an initial luminance of 5000 cd / m² and the light-emitting element 4 was driven under the condition of constant current density. 2

[0271] As a result, it was found that the light-emitting element 4 using 2PCCzPDBq-02, which is one aspect of the present invention, is a long-life light-emitting element with high reliability.

[0272] ​​​​​​​The results of measuring the amount of voltage change during the reliability test are shown in Fig. 34(B). The vertical axis represents the amount of voltage change (V), and the horizontal axis represents the driving time (h) of the element. As can be seen from these results, it can be understood that the light-emitting element 4 has a small voltage increase when driven with a constant current. For example, looking at the amount of voltage increase after driving for about 500 hours, the light-emitting element 4 is about 0.01 V. On the other hand, when the 2PC CzPDBq-02 of the light-emitting element 4 was replaced with 2mDBTBPDBq-II to fabricate a comparative light-emitting element 9 and driven in the same manner, the amount of voltage increase after driving for about 500 hours was about 0.06 V. That is, compared with the comparative light-emitting element 9, the amount of voltage increase of the light-emitting element 4 is suppressed to about one-sixth, indicating a remarkable effect. In addition, 2PCCzPDBq-02 forms an exciplex with PCBBiF (since the mixed film of this dibenzoquinoxaline compound and PCBBiF exhibits green light emission with a longer wavelength than the single film of the dibenzoquinoxaline compound or the single film of PCBBiF). Also, since the HOMO level of 2PCCzPDB q-02 is -5.68 eV, ΔE HOMO in the light-emitting layer of the light-emitting element 4 is 0.32 eV. From this result, it can be understood that it is important to set ΔE to 0.4 eV or less.

[0273] q-02 is -5.68 eV, so ΔE E HOMO in the light-emitting layer of the light-emitting element 4 is 0.32 eV. From this result, it can be understood that it is important to set ΔE HOMO to 0.4 eV or less. This is found to be important.

[0274] Also, the HOMO level of BPAFLP used in the hole transport layer is -5.51 eV. Therefore, the HOMO level of the third organic compound used in the hole transport layer is lower than the HOMO level of PCBBiF, which is the second organic compound, and is also lower than the HOMO level of PCBBiF, which is the second organic compound, and the HOM O level of the first organic compound (2PCCzPDBq-02). PCBBiF and the HOM It can be seen that it is located between the O levels. This is important from the perspective of injecting holes not only into the second organic compound but also injecting a part into the first organic compound.

Example

[0275] ≪Synthesis Example 5≫ In this example, as a synthesis method according to an aspect of the present invention, 2-{3’-[3-(N-phenyl -9H-carbazol-3-yl)-9H-carbazol-9-yl]biphenyl-3 -yl}dibenzo[f,h]quinoxaline (abbreviation 2mPCCzBPDBq) (structural formula (1 22)) will be described. The structure of 2mPCCzBPDBq is shown below as follows.

[0276]

Chemical formula

[0277] <2-{3’-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carb azole-9-yl]biphenyl-3-yl}dibenzo[f,h]quinoxaline (abbreviation 2m PCCzBPDBq) synthesis> First, 2-(3’-bromobiphenyl-3-yl)dibenzo[f,h]quinoxaline 2. 0 g (4.3 mmol), 3-(9-phenyl-9H-carbazol-3-yl)-9H -carbazole 1.8 g (4.3 mmol), sodium tert-butoxide 0.8 3 g (8.6 mmol) were placed in a 100 mL three-necked flask and mixed, and the flask was purged with nitrogen and then 22 mL of mesitylene was added to this mixture, the inside of the flask was put under reduced pressure, and it was degassed by stirring for a while.

[0278] Next, to this mixture, bis(dibenzylideneacetone)palladium(0) (abbreviation: Pd( dba) 2 ) 25 mg (0.040 mmol) and 2-dicyclohexylphosphino-2’ ,6’-dimethoxybiphenyl (S-Phos) 35 mg (0.09 mmol) were added . After the mixture was stirred at 150 °C for 23 hours under a nitrogen stream and a predetermined time had elapsed, water and toluene were added to the mixture. The aqueous layer of the obtained filtrate was extracted with toluene, and the extraction solution and the organic layer were combined, washed with an aqueous sodium hydrogen carbonate solution and saturated brine, and dried over magnesium sulfate. The obtained mixture was filtered naturally, and the filtrate was concentrated to obtain an oily substance. The oily substance was dissolved in toluene , and this solution was suction-filtered through a laminate of celite and alumina. The obtained filtrate was concentrated to obtain a brown oily substance. This oily substance was purified by high-performance liquid chromatography. Column chromatography was performed by using chloroform as the developing solvent (column pressure 4.5 MPa, flow rate 100 mL / min, retention time 45 minutes, injection volume 0.9 g / 30 mL). The obtained fraction was concentrated and recrystallized from hexane, and as a result, 0. 66 g of the yellow powder of the target product was obtained in a yield of 18%.

[0279] 0.66 g of the obtained yellow powdery solid of the target product was purified by sublimation using the train sublimation method. The sublimation purification conditions were as follows: pressure 2.6 Pa, flowing argon gas at a flow rate of 5 mL / min, while heating at 385 °C. After sublimation purification, 0.5 g of the yellow glassy solid of 2mPCCzBPDBq was obtained in a recovery rate of 83%. The synthesis scheme of this step is shown in the following (e-1). is shown below.

[0280]

Chemical formula

[0281] Analysis of the yellow powdery solid obtained in the above step by nuclear magnetic resonance spectroscopy ( 1 1H-NMR) The results are shown below. Also, 1 the 1H-NMR chart is shown in FIGS. 35(A) and (B). Note that FIG. 35(B) is an enlarged view of FIG. 35(A) with the horizontal axis (δ) in the range of 7.0 (ppm) to 10 (ppm). From this, in the above step, 2-{3’-[3- (N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]vinyl }-3-yl}dibenzof[h]quinoxaline (abbreviation 2mPCCzBPDBq) (Structural formula (122)) was found to be obtained.

[0282] 1 1H NMR (CDCl 3 , 500 MHz): δ (ppm) = 7.30 - 7.37 (m, 2H), 7.41 - 7.53 (m, 5H), 7.59 - 7.89 (m, 18H), 8.0 4 (dd, J = 1.7 Hz, 1H), 8.23 (d, J = 7.5 Hz, 1H), 8.28 (d, 8.0 Hz, 1H), 8.35 (d, J = 8.0 Hz, 1H), 8.48 (dd, J = 11.4 Hz, J = 1.7 Hz, 2H), 8.66 (d, J = 8.1 Hz, 1H), 8.70 (s, 1H), 9.25 (dd, J = 6.3 Hz, J = 1.1 Hz, 1H), 9 .43 (dd, J = 7.5 Hz, J = 1.7 Hz, 1H), 9.47 (s, 1H).

Example

[0283] In this example, a light-emitting device 5 using a dibenzof[h]quinoxaline derivative 2mPCC zPDBq (structural formula (101)), which is one aspect of the present invention, and a comparative material 2-[3-(9H-carb ​[[9H - carbazol - 9 - yl)phenyl]dibenz[f,h]quinoxaline (abbreviation: 2mDBTP) Comparative light - emitting device 6 using DBq - II), and comparative light - emitting device 7 using the comparative material 2mCzPDBq were fabricated. The fabrication of each light - emitting device was basically the same as in Example 5, so it is omitted. Also, the chemical formulas of the materials used in this example are shown below.

[0284] [Chemical formula]

[0285] [Fabrication of Light - Emitting Device 5, Comparative Light - Emitting Device 6, and Comparative Light - Emitting Device 7] The device structures of the light - emitting device 5, comparative light - emitting device 6, and comparative light - emitting device 7 fabricated in this example are shown in Table 6.

[0286] [Table 6]

[0287] Also, the fabricated light - emitting device 5, comparative light - emitting device 6, and comparative light - emitting device 7 were sealed in a glove box under a nitrogen atmosphere so as not to be exposed to the air (a sealing material was applied around the device, and UV treatment and heat treatment at 80 °C for 1 hour were performed during sealing).

[0288] [Operating Characteristics of Light - Emitting Device 5, Comparative Light - Emitting Device 6, and Comparative Light - Emitting Device 7] The operating characteristics of the fabricated light - emitting device 5, comparative light - emitting device 6, and comparative light - emitting device 7 were measured. The measurement was performed at room temperature (an atmosphere maintained at 25 °C).

[0289] The current density - luminance characteristics of each light - emitting device are shown in Fig. 36, the voltage - luminance characteristics are shown in Fig. 37, the luminance - current efficiency characteristics are shown in Fig. 38, and the voltage - current characteristics are shown in Fig. 39, respectively.

[0290] Also, the main initial characteristic values of the light-emitting element 5, the comparative light-emitting element 6, and the comparative light-emitting element 7 in the vicinity of 1000 cd / m 2 are shown in Table 7 below.

[0291]

Table 7

[0292] Also, the emission spectra when a current is passed through the light-emitting element 5, the comparative light-emitting element 6, and the comparative light-emitting element 7 at a current density of 2.5 mA / cm 2 are shown in Fig. 40. As shown in Fig. 40, the light-emitting element 5, the comparative light-emitting element 6, and the comparative light-emitting element 7 all showed spectra having a peak at around 544 nm derived from [Ir(tBuppm) (ac 2 (ac)].

[0293] Also, the results of the reliability tests for the light-emitting element 5, the comparative light-emitting element 6, and the comparative light-emitting element 7 are shown in Fig. 41(A). In Fig. 41(A), the vertical axis represents the normalized luminance (%) with the initial luminance set to 100%, and the horizontal axis represents the driving time (h) of the element. The reliability test was conducted by setting the initial luminance to 5000 cd / m and driving the light-emitting element 5, the comparative light-emitting element 6 2 , and the comparative light-emitting element 7 under the condition of a constant current density.

[0294] As a result, it was found that the light-emitting element 5 using 2mPCCzPDBq, which is one aspect of the present invention, is a long-life light-emitting element having higher reliability than the comparative light-emitting element 6 using 2mDB TPDBq-II and the comparative light-emitting element 7 using 2mCzPDBq.

[0295] Also, the results of measuring the amount of voltage change during the reliability test are shown in Fig. 41(B). The vertical axis represents the voltage change ​​​​The vertical axis indicates the quantity (V), and the horizontal axis indicates the driving time (h) of the element. As can be seen from this result, the light emission Element 5 has a smaller voltage increase when driven with a constant current compared to comparative light-emitting element 6 and comparative light-emitting element 7 as can be seen. For example, looking at the voltage increase amount after driving for about 1000 hours, comparative light-emitting element 6 is about 0.31 V, and comparative light-emitting element 7 is about 0.50 V, while light-emitting element 5 is about 0.0 4 V. That is, compared to comparative light-emitting element 6 and comparative light-emitting element 7, the voltage increase amount of light-emitting element 5 is very much suppressed, and it can be seen that this is a remarkable effect.

[0296] Also, 2mPCCzPDBq, 2mDBTPDBq-II, and 2mCzPDBq all form an exciplex with PCBBiF (since the mixed films of these dibenzoquinoxaline compounds and PCBB iF all exhibit longer-wavelength yellow-green light emission compared to the single films of each dibenzoquinoxaline compound and the single film of PCBBiF ). Also, the HOMO levels of 2mPCCzPDBq, 2mDBTPD Bq-II, 2mCzPDBq, and PCBBiF are -5. 63 eV, -6.22 eV, -5.91 eV, and -5.36 eV, respectively. Note that the HOMO level was calculated from cyclic voltammetry (CV) measurements.

[0297] From the measurement results of the HOMO level, ΔE HOMO in the light-emitting layer of each light-emitting element was calculated. The results are summarized in Table 8.

[0298]

Table 8

[0299] From this result, it can be seen that it is important that ΔE HOMO is 0.4 eV or less, more preferably 0.3 eV or less. ​

[0300] In addition, the HOMO level of BPAFLP used in the hole transport layer is -5.51 eV. Therefore, the HOMO level of the third organic compound used in the hole transport layer is lower than the HOMO level of PCBBiF, which is the second organic compound, and is also located between the HOMO level of PCBBiF, which is the second organic compound, and the HOMO level of the first organic compound (2mPCCzPDBq). This is important from the perspective of injecting holes not only into the second organic compound but also into part of the first organic compound.

Example

[0301] In this example, a light-emitting device 8 using the dibenzo[f,h]quinoxaline derivative 2mPCCzBPDBq, which is one aspect of the present invention, was fabricated. The fabrication of the light-emitting device 8 is basically the same as that in Example 5, so it is omitted. The chemical formulas of the materials used in this example are shown below.

[0302]

Chemical formula

[0303] ≪Fabrication of Light-Emitting Device 8≫ The device structure of the light-emitting device 8 fabricated in this example is shown in Table 9.

[0304]

Table 9

[0305] In addition, the fabricated light-emitting device 8 was sealed in a glove box under a nitrogen atmosphere so as not to be exposed to the air (a sealing material was applied around the device, and UV treatment and heat treatment were performed at 80 °C for 1 hour during sealing). ​​​​​​​​​

[0306] ≪Operating Characteristics of Light-Emitting Element 8≫ The operating characteristics of the fabricated light-emitting element 8 were measured. The measurement was carried out at room temperature (maintained at 25 °C atmosphere).

[0307] The current density-luminance characteristics of the light-emitting element 8 are shown in FIG. 42, the voltage-luminance characteristics are shown in FIG. 43, the luminance-current efficiency characteristics are shown in FIG. 44, and the voltage-current characteristics are shown in FIG. 45, respectively.

[0308] Also, the main initial characteristic values of the light-emitting element 8 near 1000 cd / m 2 are shown in Table 10 below. Shown.

[0309]

Table 10

[0310] Also, the emission spectrum of the light-emitting element 8 when a current was passed through it at a current density of 2.5 mA / cm 2 is shown in FIG. 46. As shown in FIG. 46, the light-emitting element 8 showed a spectrum having a peak near 584 nm derived from 2 [Ir(dppm) (acac)]

Example

[0311] In this example, a light-emitting element according to one aspect of the present invention was fabricated and a storage test was conducted.

[0312] In this example, a light-emitting element 1A, a light-emitting element 2A, a comparative light-emitting element 3A, a light-emitting element 4A, and a light-emitting element 8A were fabricated. The light-emitting element 1A had the same configuration as the light-emitting element 1 in Example 5 and was fabricated by the same manufacturing method. The light-emitting element 2A was the light-emitting element 2 in Example 5, the comparative light-emitting element 3 A was the comparative light-emitting element 3 in Example 5, the light-emitting element 4A was the light-emitting element 4 in Example 6, and the light-emitting element 8 A was fabricated with the same structure and by the same fabrication method as the light-emitting element 8 of Example 9.

[0313] In the storage test of this example, each light-emitting element was stored in a thermostat maintained at 100°C, and after a predetermined time had elapsed, the operating characteristics were measured. The measurement was performed at room temperature (atmosphere maintained at 25°C) after taking the element out of the thermostat. First, the voltage-current characteristics of the light-emitting element 1A when stored at 100°C for a predetermined time are shown in FIG. 47, and the luminance-external quantum efficiency characteristics are shown in FIG. 48. In FIG. 47, the horizontal axis represents voltage (V), and the vertical axis represents current (mA). In FIG. 48, the horizontal axis represents luminance (cd / m ²), and the vertical axis represents external quantum efficiency (%).

[0314] Next, the voltage-current characteristics of the light-emitting element 2A when stored at 100°C for a predetermined time are shown in FIG. 49, and the luminance-external quantum efficiency characteristics are shown in FIG. 50. In FIG. 49, the horizontal axis represents voltage (V), and the vertical axis represents current (mA). In FIG. 50, the horizontal axis represents luminance (cd / m ²), and the vertical axis represents external quantum efficiency (%). Next, the voltage-current characteristics of the comparative light-emitting element 3A when stored at 100°C for a predetermined time are shown in FIG. 51, and the luminance-external quantum efficiency characteristics are shown in FIG. 52. In FIG. 51, the horizontal axis represents voltage (V), and the vertical axis represents current (mA). In FIG. 52, the horizontal axis represents luminance (cd / m 2 ²), and the vertical axis represents external quantum efficiency (%). In FIG. 52, since no light emission was observed for storage exceeding 20 hours, data for storage exceeding 20 hours could not be obtained.

[0315] Next, the voltage-current characteristics of the light-emitting element 2A when stored at 100°C for a predetermined time are shown in FIG. 49, and the luminance-external quantum efficiency characteristics are shown in FIG. 50. In FIG. 49, the horizontal axis represents voltage (V), and the vertical axis represents current (mA). In FIG. 50, the horizontal axis represents luminance (cd / m ²), and the vertical axis represents external quantum efficiency (%). Next, the voltage-current characteristics of the comparative light-emitting element 3A when stored at 100°C for a predetermined time are shown in FIG. 51, and the luminance-external quantum efficiency characteristics are shown in FIG. 52. In FIG. 51, the horizontal axis represents voltage (V), and the vertical axis represents current (mA). In FIG. 52, the horizontal axis represents luminance (cd / m 2 ²), and the vertical axis represents external quantum efficiency (%).

[0316] Next, the voltage-current characteristics of the comparative light-emitting element 3A when stored at 100°C for a predetermined time are shown in FIG. 51, and the luminance-external quantum efficiency characteristics are shown in FIG. 52. In FIG. 51, the horizontal axis represents voltage (V), and the vertical axis represents current (mA). In FIG. 52, the horizontal axis represents luminance (cd / m ²), and the vertical axis represents external quantum efficiency (%). In FIG. 52, since no light emission was observed for storage exceeding 20 hours, data for storage exceeding 20 hours could not be obtained. In FIG. 51, the horizontal axis represents voltage (V), and the vertical axis represents current (mA). In FIG. 52, the horizontal axis represents luminance (cd / m 2 ²), and the vertical axis represents external quantum efficiency (%). In FIG. 52, since no light emission was observed for storage exceeding 20 hours, data for storage exceeding 20 hours could not be obtained.

[0317] ​​​​Next, the voltage-current characteristics of the light-emitting element 4A when stored at 100°C for a predetermined time are shown in FIG. 53 , and the luminance-external quantum efficiency characteristics are shown in FIG. 54. In FIG. 53, the horizontal axis represents voltage (V), and the vertical axis represents current (mA). In FIG. 54, the horizontal axis represents luminance (cd / m 2 ), and the vertical axis represents the external quantity quantum efficiency (%).

[0318] Next, the voltage-current characteristics of the light-emitting element 8A when stored at 100°C for a predetermined time are shown in FIG. 55 , and the luminance-external quantum efficiency characteristics are shown in FIG. 56. In FIG. 55, the horizontal axis represents voltage (V), and the vertical axis represents current (mA). In FIG. 56, the horizontal axis represents luminance (cd / m 2 ), and the vertical axis represents the external quantity quantum efficiency (%).

[0319] From FIGS. 47 to 50 and FIGS. 53 to 56, it can be seen that the light-emitting elements 1A, 2A, 4A, and 8A show little change in voltage-current characteristics and luminance-external quantum efficiency characteristics despite being stored at 100°C for 500 hours, indicating little deterioration of the element characteristics due to high-temperature storage . On the other hand, from FIGS. 51 and 52, it can be seen that the comparative light-emitting element 3A shows significant changes in voltage-current characteristics and luminance-external quantum efficiency characteristics when stored at 100°C, indicating that the element characteristics are deteriorated due to high-temperature storage. From FIG. 51, it can be seen that the comparative light-emitting element 3A cannot maintain the initial insulation after 100 hours, and a leakage current occurs. From FIG. 52, it can be seen that a non-light-emitting defect has occurred. Therefore, it can be seen that by using the compound of the present invention, the heat resistance of the light-emitting element during high-temperature storage is significantly improved . . . .

Explanation of Reference Numerals

[0320] 100 Light-emitting layer 101 First organic compound (h) 102 Second organic compound (a) 103 Phosphorescent compound (g) 104 Hole transport layer 105 Hole transporting compound (p) 201 First electrode 202 EL layer 203 Second electrode 211 Hole injection layer 212 Hole transport layer 213 Light emitting layer 214 Electron transport layer 215 Electron injection layer 401 First electrode 402(1) First EL layer 402(2) Second EL layer 402(n - 1) (n - 1)th EL layer 402(n) nth EL layer 404 Second electrode 405 Charge generation layer 405(1) First charge generation layer 405(2) Second charge generation layer 405(n - 1) (n - 1)th charge generation layer 501 Substrate 502 FET 503 First electrode 504 Partition wall 505 EL layer 506R, 506G, 506B, 506Y Light emitting region 507R, 507G, 507B, 507Y Light emitting element 508R, 508G, 508B, 508Y Coloring layer 509 Black layer (black matrix) 510 Second electrode 511 Sealing substrate 601 Element substrate 602 Pixel portion 603 Driving circuit portion (source line driving circuit) 604a, 604b Driving circuit portion (gate line driving circuit) 605 Sealing material 606 Sealing substrate 607 Wiring 608 FPC (Flexible Printed Circuit) 609 FET 610 FET 611 FET for Switching 612 FET for Current Control 613 First Electrode (Anode) 614 Insulator 615 EL Layer 616 Second Electrode (Cathode) 617 Light-Emitting Element 618 Space 1100 Substrate 1101 First Electrode 1102 EL Layer 1103 Second Electrode 1111 Hole Injection Layer 1112 Hole Transport Layer 1113 Light-Emitting Layer 1114 Electron Transport Layer 1115 Electron Injection Layer 7100 Television Device 7101 Housing 7103 Display Unit 7105 Stand 7107 Display Unit 7109 Operation Key 7110 Remote Control Operation Unit 7201 Main Body 7202 Housing 7203 Display Unit 7204 Keyboard 7205 External Connection Port 7206 Pointing Device 7302 Housing 7304 Display Panel 7305 Icon Representing Time 7306 Other Icons 7311 Operation Button 7312 Operation Button 7313 Connection Terminal 7321 Band 7322 Fastener 7400 Mobile Phone 7401 Housing 7402 Display section 7403 Operation button 7404 External connection section 7405 Speaker 7406 Microphone 7407 Camera 8001 Lighting device 8002 Lighting device 8003 Lighting device 8004 Lighting device 9310 Portable information terminal 9311 Display panel 9313 Hinge 9315 Housing

Claims

1. A light-emitting device having a light-emitting layer between an anode and a cathode, the light-emitting layer includes a first organic compound having an electron transport property and a hole transport property, a second organic compound having a hole transport property, and a light-emitting substance; the first organic compound contains a nitrogen-containing heteroaromatic ring composed of a 6-membered ring and a bicarbazole skeleton, the first organic compound and the second organic compound are a combination that forms an exciplex, a HOMO level of the first organic compound is lower than a HOMO level of the second organic compound; A light-emitting element, wherein a difference between a HOMO level of the first organic compound and a HOMO level of the second organic compound is 0.4 eV or less.

2. A light-emitting device having a light-emitting layer between an anode and a cathode, the light-emitting layer includes a first organic compound having an electron transport property and a hole transport property, a second organic compound having a hole transport property, and a light-emitting substance; the first organic compound contains a nitrogen-containing heteroaromatic ring composed of a 6-membered ring and a bicarbazole skeleton, the first organic compound and the second organic compound are a combination that forms an exciplex, a HOMO level of the first organic compound is lower than a HOMO level of the second organic compound; A light-emitting element, wherein a difference between a HOMO level of the first organic compound and a HOMO level of the second organic compound is 0.3 eV or less.

3. In claim 1 or claim 2, The light-emitting element, wherein the light-emitting material is a phosphorescent compound.

4. A light-emitting device comprising: a light-emitting element according to any one of claims 1 to 3; and a transistor; the transistor is electrically connected to the light-emitting element.

5. A light-emitting element according to any one of claims 1 to 3, or a light-emitting device according to claim 4, An electronic device having at least one of a connection terminal and an operation key.

6. A lighting device having the light-emitting device described in claim 4 and a housing.

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