Organometallic complexes, organic light-emitting devices containing the same, display devices, imaging devices, electronic devices, lighting devices, and mobile bodies

Abstract

To provide an organic metal complex having a small half-width of an emission spectral peak and high luminous efficiency.SOLUTION: An organic metal complex is represented by, for example, a reaction product of the formula illustrated below.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an organometallic complex having a narrow emission spectrum peak, an organic light-emitting device including the same, a display device, an imaging device, an electronic apparatus, a lighting device, and a moving object. [Background Art]

[0002] An organic light-emitting device (also called an organic electroluminescent device or an organic EL device) is an electronic device including a first electrode, a second electrode, and an organic compound layer disposed between these electrodes. By injecting electrons and holes from the pair of electrodes, excitons of a luminescent organic compound in the organic compound layer are generated, and when the excitons return to the ground state, the organic light-emitting device emits light. Recent progress in organic light-emitting devices has been remarkable, and features thereof include low driving voltage, various emission wavelengths, high-speed response, and enabling thin and light-weight light-emitting devices.

[0003] To improve the performance of organic light-emitting devices, high-performance luminescent organic compounds are further demanded, and development is actively underway. However, for phosphorescent materials typified by iridium complexes, it is known that it is difficult to achieve both improved color purity by narrowing the peak width of the emission spectrum and improved luminous efficiency. Patent Document 1 describes the following compound A as a phosphorescent material having high luminous efficiency, and Patent Document 2 describes compound B as a compound having a narrow emission spectrum peak width.

[0004] [Chemical Formula] [Prior Art Documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-114137 [Patent Document 2] US Patent Application Publication No. 2017 / 0012223 Summary of the Invention Problems to be Solved by the Invention

[0006] Compound A described in Patent Document 1 is a compound having high luminous efficiency, but does not have a sufficiently narrow peak width of an emission spectrum. Although Compound B described in Patent Document 2 has a narrow peak width of an emission spectrum, its luminous efficiency is insufficient.

[0007] It is known that when an attempt is made to steepen the emission spectrum of a phosphorescent material, the luminous efficiency decreases, and there has been a demand for an organometallic complex that has a narrow peak width of an emission spectrum and high luminous efficiency.

[0008] The present invention has been made in view of the above problems, and an object of the present invention is to provide an organometallic complex that has a small half-value width of a peak in an emission spectrum and high luminous efficiency. Means for Solving the Problems

[0009] The present invention provides an organometallic complex represented by the following formula (1). ML m L' n L'' l (1)

[0010] In formula (1), M represents a transition metal, and L m L' n L'' l each represent a different ligand. m is an integer of 1 to 3, n is an integer of 0 to 2, l is an integer of 0 to 2, and m+n+l=3. ML m is a structure represented by the following general formula (2).

[0011] Chemical Formula

[0012] In general formula (2), R 11 to R 14Each of these groups is independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted amino group, a silyl group, and a cyano group.

[0013] X is selected from CRR', SiRR', S, SO, and SO2. R and R' are independently selected from substituted or unsubstituted alkyl groups, substituted or unsubstituted aryl groups, and halogen atoms, respectively.

[0014] Y1 to Y6 are independently selected from carbon atoms and nitrogen atoms, respectively.

[0015] If Y1 to Y6 is a carbon atom, that carbon atom may be substituted with an alkyl group or an aryl group.

[0016] If Y3 to Y6 are carbon atoms, these carbon atoms may bond with adjacent carbon atoms to form a ring structure.

[0017] ML' n and ML'' l These are independently selected from equation (4) or (5) below.

[0018] [ka]

[0019] In equations (4) and (5), R 31 ~R 38 and R 41 ~R 43 Each of these is independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aralkyl group, a substituted amino group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group. [Effects of the Invention]

[0020] According to the present invention, it is possible to provide organometallic complexes with a small half-width of the peaks in the emission spectrum and high luminescence efficiency. [Brief explanation of the drawing]

[0021] [Figure 1] This is the molecular structure model of example compound A-1. [Figure 2] (a) A schematic cross-sectional view showing an example of a pixel of a display device according to one embodiment of the present invention. (b) A schematic cross-sectional view showing an example of a display device using an organic light-emitting element according to one embodiment of the present invention. [Figure 3] This is a schematic diagram illustrating an example of a display device according to one embodiment of the present invention. [Figure 4] (a) A schematic diagram showing an example of an imaging device according to one embodiment of the present invention. (b) A schematic diagram showing an example of an electronic device according to one embodiment of the present invention. [Figure 5] (a) A schematic diagram showing an example of a display device according to one embodiment of the present invention. (b) A schematic diagram showing an example of a foldable display device. [Figure 6] (a) A schematic diagram showing an example of a lighting device according to one embodiment of the present invention. (b) A schematic diagram showing an example of an automobile having a vehicle light fixture according to one embodiment of the present invention. [Figure 7] (a) A schematic diagram showing an example of a wearable device according to one embodiment of the present invention. (b) A schematic diagram showing an example of a wearable device according to one embodiment of the present invention, which includes an imaging device. [Modes for carrying out the invention]

[0022] An iridium complex according to one embodiment of the present invention is represented by the following formula (1). ML m L' n L'' l (1)

[0023] In equation (1), M represents a transition metal, and L mL' n L'' l Each of these represents a different ligand. m is an integer from 1 to 3, n is an integer from 0 to 2, and l is an integer from 0 to 2, and m + n + l = 3. ML m This structure is represented by the following general formula (2).

[0024] [ka]

[0025] In general formula (2), R 11 ~R 14 Each of these groups is independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted amino group, a silyl group, and a cyano group.

[0026] X is selected from CRR', SiRR', S, SO, and SO2. R and R' are independently selected from substituted or unsubstituted alkyl groups, substituted or unsubstituted aryl groups, and halogen atoms, respectively.

[0027] Y1 to Y6 are independently selected from carbon atoms and nitrogen atoms, respectively.

[0028] If Y1 to Y6 is a carbon atom, the carbon atom may be substituted with an alkyl group or an aryl group. If it is not substituted with an alkyl group or an aryl group, it has a hydrogen atom.

[0029] If Y3 to Y6 are carbon atoms, these carbon atoms may bond with adjacent carbon atoms to form a ring structure. When carbon atoms bond to each other to form a ring structure, it may be an alicyclic structure, an aromatic ring, or a heterocyclic structure, and the number of fused rings constituting the ring structure may be 1 to 3, with 1 being preferable.

[0030] The aforementioned Y1 may be a nitrogen atom. When Y1 is a nitrogen atom, the highest occupied molecular orbital (HOMO) of the organometallic complex becomes lower, so the emission wavelength becomes shorter. On the other hand, the aforementioned Y4 or the aforementioned Y 10 These atoms may be nitrogen atoms. When these are nitrogen atoms, the lowest unoccupied molecular orbital (LUMO) of the organometallic complex becomes lower, so the emission wavelength becomes even longer.

[0031] When the carbon atoms of Y3 to Y6 bond with adjacent carbon atoms to form a ring structure, it is preferable that the structure be represented by the following formula (3). This is because it results in an organometallic complex with higher luminescence efficiency than when the ring structure is formed at other positions.

[0032] [ka]

[0033] In equation (3), R 21 ~R 26 Each of these groups is independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted amino group, a silyl group, and a cyano group.

[0034] X is selected from CRR', SiRR', S, SO, and SO2. R and R' are independently selected from substituted or unsubstituted alkyl groups, substituted or unsubstituted aryl groups, and halogen atoms, respectively.

[0035] Early Y7 to the aforementioned Y 12 These atoms are independently selected from carbon atoms and nitrogen atoms, respectively.

[0036] The above Y7 to the above Y 12 If the carbon atom is a carbon atom, that carbon atom may be substituted with an alkyl group or an aryl group.

[0037] The Y1 to the Y12 All of the atoms may be carbon atoms. When all of them are carbon atoms, the organometallic complex is highly stable.

[0038] ML' n and ML'' l These are independently selected from equation (4) or (5) below.

[0039] [ka]

[0040] In equations (4) and (5), R 31 ~R 38 and R 41 ~R 43 Each of these is independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aralkyl group, a substituted amino group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group.

[0041] In equation (5), R 41 , R 43 This may be an alkyl group having 1 to 8 carbon atoms. It may be a methyl group, an ethyl group, an isopropyl group, a t-butyl group, or a -CH(C2H5)2 group. 41 ~R 43 By using bulky substituents, the heat resistance and sublimation properties of organometallic complexes can sometimes be improved. In particular, R 41 , R 42 , R 43 The combination may be isopropyl group, hydrogen atom, isopropyl group. 41 , R 42 , R 43 The combination may be -CH(C2H5)2, hydrogen atom, -CH(C2H5)2. 41 , R 42 , R 43 The combination may be a t-butyl group, a hydrogen atom, and a t-butyl group. 41 , R 42 , R 43The combination may be an ethyl group, a hydrogen atom, and a methyl group.

[0042] In this specification, the transition metal atom may be trivalent, and specifically includes Ir, Co, Ru, Os, Rh, Re, etc., with Ir being preferred.

[0043] In this specification, halogen atoms include, but are not limited to, fluorine, chlorine, bromine, and iodine. Among halogen atoms, fluorine atoms are preferred.

[0044] In this specification, alkyl groups include alkyl groups having 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and even more preferably 1 to 4 carbon atoms. Specifically, examples include, but are not limited to, methyl groups, ethyl groups, n-propyl groups, isopropyl groups, n-butyl groups, tert-butyl groups, secondary butyl groups, octyl groups, cyclopentyl groups, cyclohexyl groups, 1-adamantyl groups, and 2-adamantyl groups.

[0045] In this specification, the alkoxy group is an alkoxy group having 1 to 10 carbon atoms, more preferably having 1 to 6 carbon atoms, and even more preferably having 1 to 4 carbon atoms. Specifically, examples include, but are not limited to, a methoxy group, an ethoxy group, a propoxy group, a 2-ethyl-xyloxy group, and a benzyloxy group.

[0046] In this specification, an amino group may be unsubstituted or substituted with an alkyl group, an aryl group, or an amino group. Alkyl groups, aryl groups, and amino groups may have halogen atoms as substituents. Aryl groups and amino groups may have alkyl groups as substituents. The substituted alkyl groups of the amino group may be bonded to each other to form a ring. Specifically, examples include, but are not limited to, N-methylamino group, N-ethylamino group, N,N-dimethylamino group, N,N-diethylamino group, N-methyl-N-ethylamino group, N-benzylamino group, N-methyl-N-benzylamino group, N,N-dibenzyloamino group, anilino group, N,N-diphenylamino group, N,N-dinaphthylamino group, N,N-difluorenylamino group, N-phenyl-N-tolylamino group, N,N-ditolylamino group, N-methyl-N-phenylamino group, N,N-dianisorylamino group, N-mesityl-N-phenylamino group, N,N-dimesitylamino group, N-phenyl-N-(4-tert-butylphenyl)amino group, N-phenyl-N-(4-trifluoromethylphenyl)amino group, N-piperidyl group, etc.

[0047] In this specification, the aryl group refers to an aryl group having 6 to 18 carbon atoms. Specifically, this includes the phenyl group, naphthyl group, indenyl group, biphenyl group, terphenyl group, fluorenyl group, phenanthryl group, triphenylenyl group, and the like.

[0048] In this specification, a heterocyclic group refers to a heterocyclic group having 3 to 15 carbon atoms. The heterocyclic group may have nitrogen, sulfur, and oxygen as heteroatoms. Specifically, examples include, but are not limited to, pyridyl, pyrazyl, pyrimidyl, triazyl, imidazolyl, oxazolyl, oxadiazolyl, thiazolyl, thiadiazolyl, carbazolyl, acridinyl, phenantrolyl, furanyl, thiophenyl, dibenzofuranyl, and dibenzothiophenyl groups.

[0049] In this specification, the aryloxy group includes, but is not limited to, a phenoxy group and a thienyloxy group.

[0050] In this specification, silyl groups include, but are not limited to, trimethylsilyl groups and triphenylsilyl groups.

[0051] The alkyl groups, alkoxy groups, amino groups, aryl groups, heterocyclic groups, and aryloxy groups mentioned above may have a deuterium atom as a substituent. Examples of alkyl groups having a deuterium atom as a substituent include, but are not limited to, -CD3, (-CD2CH3), and (-CD2CD3).

[0052] The alkyl groups, alkoxy groups, amino groups, aryl groups, heterocyclic groups, and aryloxy groups mentioned above may have halogen atoms as substituents. Examples of halogen atoms include fluorine, chlorine, bromine, and bromine, and may be fluorine atoms. In particular, alkyl groups may be trifluoride methyl groups (-CF3) or pentafluoroethyl groups (-C2F5) by having a fluorine atom.

[0053] The above amino groups, aryl groups, heterocyclic groups, and aryloxy groups may have alkyl groups as substituents. The alkyl group may have 1 to 10 carbon atoms. More specifically, it may be a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, or a tert-butyl group.

[0054] The alkyl groups, alkoxy groups, amino groups, aryl groups, heterocyclic groups, and aryloxy groups mentioned above may have an aryl group as a substituent. The aryl group may have 6 to 12 carbon atoms. More specifically, it may be a phenyl group, a biphenyl group, or a naphthyl group.

[0055] The alkyl groups, alkoxy groups, amino groups, aryl groups, heterocyclic groups, and aryloxy groups mentioned above may have heterocyclic groups as substituents. The heterocyclic group may have 3 to 9 carbon atoms. The heterocyclic group may have nitrogen, sulfur, and oxygen as heteroatoms. More specifically, it may be a pyridyl group or a pyrrolyl group.

[0056] The alkyl groups, alkoxy groups, amino groups, aryl groups, heterocyclic groups, and aryloxy groups mentioned above may have an amino group as a substituent. The amino group may have an alkyl group or an aryl group, and the alkyl groups may be bonded to each other to form a ring. Specifically, these may be a dimethylamino group, a diethylamino group, a dibenzylamino group, a diphenylamino group, or a dicylamino group.

[0057] The alkyl groups, alkoxy groups, amino groups, aryl groups, heterocyclic groups, and aryloxy groups described above may have substituents such as aralkyl groups (e.g., benzyl groups), alkoxy groups (e.g., methoxy groups, ethoxy groups, propoxy groups), aryloxy groups (e.g., phenoxy groups), cyano groups, etc. However, the substituents are not limited to these.

[0058] Next, we will explain the properties of organometallic complexes represented by general formula (1). Figure 1 is a molecular model of an organometallic complex represented by the following chemical structure formula.

[0059] [ka]

[0060] In the above chemical structural formulas, R is in formulas (2) and (3). 11 ~R 26The diagram shows the three-dimensional structure of a molecule in which is a hydrogen atom, X is two C(CH3) groups, and Y1 to Y6 are carbon atoms. The organometallic complex represented by the above chemical structural formula has a benzoisoquinoline (hereinafter referred to as BIQ) ring bonded to Ir and a phenyl group bonded to Ir. Furthermore, it has a cyclic ligand (hereinafter referred to as the main ligand) in which the phenyl group and the BIQ ring are bonded at other positions. The compound with the above chemical structural formula is an organometallic complex having two main ligands and one pivaloylmethane ligand (hereinafter referred to as the auxiliary ligand).

[0061] The organometallic complex represented by this chemical structure is the example compound A-1 described later. In the following explanation, this organometallic complex represented by this chemical structure will be referred to as "example compound A-1".

[0062] The three-dimensional structure shown in Figure 1 and the parameters for the molecular orbital calculations shown later were obtained by performing a ground state structure optimization calculation using the electronic state calculation software Gaussian09*Revision C.01. For this calculation, density functional theory was adopted as the quantum chemical calculation method, and LC-BLYP was used as the functional. The basis set used in Gaussian 09, Revision C.01 is 6-31. + G ** I used it.

[0063] Gaussian 09, Revision C.01, MJFrisch, GWTrucks, HBSchlegel, GEScuseria, MARobb, JRCheeseman, G. Scalmani, V. Barone, B. Mennucci, GAPetersson, H. Natsuji, M.Carica. X.Li, HPHratchian, AFIzmaylov, J. Bloino, G. Zheng, JLSonnenberg, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishidaji, T. Nakama, Y. O. Kindatao and O. Kindatao. H.Nakai, T.Vreven, JAMontgomery, Jr.JEPeralta, F.Ogliaro, M.Bearpark, JJHeyd, E.Brothers, KNKudin, VNStaroverov, T.Keith, R.Kobaya, Norman J.J. K.Raghavachari, A.Rendell, JCBurant, SSIyengar, J.Tomasi, M.Cossi, N.Rega, JMMillam, M.Klene, JEKnox, JBCross, V.Bakken, C.Adamo, J.G.G. REStratmann, O.Yazyev, AJAustin, R.Cammi, C.Pomelli, JWOchterski, RLMartin, K.Morokuma, VGZakrzewski, GAVoth, P.Salvador, JJDannenberg, S.Dapprich and ADD. O.Farkas、 JBForesman、 JVOrtiz、 J.Cioslowski、 and DJFox、Gaussian、Inc.Wallingford CT、2010.

[0064] In Figure 1, the example compound A-1 has two main ligands and one auxiliary ligand. The main ligand has a BIQ ring and a phenyl ring bonded to the BIQ ring, and the carbon atom adjacent to the carbon atom bonded to the phenyl ring on the BIQ ring and the carbon atom adjacent to the carbon atom bonded to the BIQ ring on the phenyl ring form a six-membered ring. The auxiliary ligand is pivaloylmethane.

[0065] The BIQ ring and the phenyl ring have not only a single bond but also another cross-linking structure, and by using a cyclic ligand, the emission spectrum has a small peak width and high luminescence efficiency.

[0066] The presence of a BIQ ring is advantageous in improving the luminescence quantum yield. To improve the efficiency of the luminescence quantum yield of phosphorescent materials such as iridium complexes, it is effective to increase the transition dipole moment in the excited state of the complex and improve the oscillator strength.

[0067] Iridium complexes containing a BIQ ring appropriately extend conjugation in a direction that moves the center of gravity of the conjugated plane further away from the metal atom. This increases the distance electrons travel from the metal atom to the ligand in the excited state of the complex, thereby increasing the transition dipole moment and improving oscillator strength. As a result, they become organometallic complexes with high luminescence efficiency.

[0068] The large dipole moment of the organometallic complex according to the present invention is shown below. The oscillator strength of each compound was calculated by molecular orbital calculations, using Ref-1 described in Patent Document 2, comparative compound 1 and comparative compound 2 which have one ring structure fused to Ref-1, and exemplary compound A-1.

[0069] The structures of Ref-1, comparative compounds 1 and 2, and example compound A-1 are shown below. Table 1 shows the values ​​of the highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO), maximum emission peak wavelength (λmax.calc), and oscillator intensity for each structure, calculated by molecular orbital calculations.

[0070] [ka]

[0071] [Table 1]

[0072] As a result, it can be seen that the oscillator strength of example compound A-1 is 1.3 times that of Ref-1, 1.3 times that of comparative compound 1, and 2.6 times that of comparative compound 2.

[0073] In other words, the BIQ ring in example compound A-1 most significantly increases the transition dipole moment of the organometallic complex, thereby increasing the oscillator intensity. This increased oscillator intensity is the most significant factor in improving luminescence efficiency.

[0074] Comparing the HOMO-LUMO energy levels of each compound in Table 1, there was no significant difference in the HOMO values ​​of each compound, but the LUMO values ​​differed considerably. In particular, comparative compound 1 has an emission wavelength in a wavelength range unsuitable for use as a light-emitting material for organic EL displays. This is because the magnitude of conjugation differs due to the difference in the ring fusion position.

[0075] Furthermore, using a cyclic ligand contributes to reducing the peak width of the emission spectrum. The broad peaks in the emission spectra of organic compounds are due to the difference between the structure in the ground state and the structure in the excited state. In other words, compounds with a small difference in structure between the ground state and the excited state have smaller peak widths in their emission spectra. Iridium complexes with cyclic ligands have a rigid structure as compounds, thus reducing the structural change between the ground state and the excited state. Therefore, the organometallic complexes according to the present invention, which have cyclic ligands, have small peak widths in their emission spectra. A small peak width means that the full width at half maximum may be 40 nm or less.

[0076] As shown in Figure 1, the structure of example compound A-1 exhibits increased rigidity due to the cyclic ligand, resulting in a structure with extremely high planarity. To demonstrate the planarity of the compounds, the dihedral angle of example compound A-1 was compared with that of comparative compound 3, which does not have a cyclic ligand. The dihedral angle was calculated using molecular orbital calculations. The results are shown in Table 2. Here, the dihedral angle refers to the angle between the BIQ ring and the phenyl ring. The dihedral angle is denoted as τ(1234). This indicates that the structures in Table 2 are numbered 1 to 4, and the dihedral angle was calculated using these four points.

[0077] [Table 2]

[0078] As a result, the dihedral angle of example compound A-1 is 0.2°, which is very small compared to 15.1° of comparative compound 3. It was revealed that example compound A-1 has very high planarity and a rigid structure. In other words, the organometallic complex according to the present invention, in which structural changes are reduced between the ground state and the excited state, has a small peak width in the emission spectrum.

[0079] Therefore, considering this in conjunction with a comparison of oscillator intensity, we found that example compound A-1 is suitable as an organometallic complex with high luminescence efficiency and a small peak width in its emission spectrum.

[0080] The following are examples of specific structural formulas of organometallic complexes according to the present invention. However, the organometallic complexes according to the present invention are not limited to these.

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[0102] The example compounds shown in groups A through D are examples of organometallic complexes represented by general formula (1). The organometallic complexes shown in group A are examples of compounds in which two main ligands L, which mainly contribute to luminescence, and one pivaloylmethane as auxiliary ligand L'' are coordinated to iridium. Compared with organometallic complexes in other groups, the organometallic complexes shown in group A have a lower molecular weight, which has the effect of allowing for a lower deposition temperature. The organic compounds shown in group B are examples of compounds in which three main ligands L are coordinated to iridium. Due to the high molecular symmetry, they are stable organometallic complexes. The organic compounds shown in group C are examples of compounds in which one main ligand L and two 2-phenylpyridine as auxiliary ligands L' are coordinated to iridium. The organic compounds shown in group D are examples of compounds in which two main ligands L and one 2-phenylpyridine as auxiliary ligand L' are coordinated to iridium. Organometallic complexes of groups C and D can be suitably used as compounds that offer a good balance of stability and deposition temperature by selecting an appropriate main ligand L and auxiliary ligand L'.

[0103] In all of the above organic compounds, the main ligand L, which primarily contributes to luminescence, is a cyclic ligand having a benzoisoquinoline or azachricene skeleton. This molecular structure achieves two effects simultaneously: it suppresses intramolecular structural changes, and the benzoisoquinoline and azachricene skeletons optimize the direction and length of the transition dipole moment, thereby increasing oscillator strength and improving the efficiency of the luminescence quantum yield. Therefore, the organometallic complexes in this embodiment tend to have a steep full width at half maximum in their emission spectra and possess both of these characteristics, resulting in a very high luminescence quantum yield.

[0104] Next, the organic light-emitting element of this embodiment will be described. The organic light-emitting element of this embodiment has at least a first electrode, a second electrode, and an organic compound layer disposed between these electrodes. One of the first electrode and the second electrode is the anode and the other is the cathode. In the organic light-emitting element of this embodiment, the organic compound layer may be a single layer or a laminate consisting of multiple layers, as long as it has a light-emitting layer. If the organic compound layer is a laminate consisting of multiple layers, the organic compound layer may have, in addition to the light-emitting layer, a hole injection layer, a hole transport layer, an electron blocking layer, a hole-exciton blocking layer, an electron transport layer, an electron injection layer, etc. Furthermore, the light-emitting layer may be a single layer or a laminate consisting of multiple layers.

[0105] In the organic light-emitting element of this embodiment, at least one layer of the organic compound layer contains the organometallic complex according to this embodiment. Specifically, the organic compound according to this embodiment is included in any of the above-mentioned light-emitting layer, hole implantation layer, hole transport layer, electron blocking layer, hole-exciton blocking layer, electron transport layer, electron implantation layer, etc. The organic compound according to this embodiment is preferably included in the light-emitting layer.

[0106] In the organic light-emitting element of this embodiment, when the organic compound according to this embodiment is included in the light-emitting layer, the light-emitting layer may consist only of the organic compound according to this embodiment, or it may consist of the organometallic complex according to this embodiment and other compounds. Here, when the light-emitting layer consists of the organometallic complex according to this embodiment and other compounds, the organic compound according to this embodiment may be used as a host or a guest in the light-emitting layer. It may also be used as an assist material that can be included in the light-emitting layer. Here, the host is the compound with the largest mass ratio among the compounds constituting the light-emitting layer. The guest is a compound with a smaller mass ratio than the host among the compounds constituting the light-emitting layer, and is responsible for the main light emission. The assist material is a compound with a smaller mass ratio than the host among the compounds constituting the light-emitting layer, and assists the light emission of the guest. The assist material is also called the second host. The host material can also be called the first organic compound, and the assist material can be called the second organic compound. The first organic compound has a higher minimum excitation singlet energy and minimum excitation triplet energy than the organometallic complex. The lowest excited triplet energy of the second organic compound may be higher than the lowest excited triplet energy of the organometallic complex and lower than the lowest excited triplet energy of the first organic compound.

[0107] When the organic compound according to this embodiment is used as a guest in the light-emitting layer, the concentration of the guest is preferably 0.01% by mass or more and 20% by mass or less, and more preferably 0.1% by mass or more and 10% by mass or less, relative to the entire light-emitting layer.

[0108] The inventors conducted various studies and found that when the organic compound according to this embodiment is used as a host or guest for the light-emitting layer, particularly as a guest for the light-emitting layer, a device can be obtained that exhibits high efficiency, high brightness, and extremely high durability. This light-emitting layer may be a single layer or a multi-layer, and it is also possible to mix the light emission with the red light emission of this embodiment by including a light-emitting material having another light emission color. A multi-layer means a state in which one light-emitting layer and another light-emitting layer are stacked. In this case, the light emission color of the organic light-emitting element is not limited to red. More specifically, it may be white or an intermediate color. In the case of white, the other light-emitting layer emits a color other than red, i.e., blue or green. Furthermore, the film is formed by vapor deposition or coating. Details of this will be explained in detail in the examples described later.

[0109] When the organometallic complex according to this embodiment is included in the light-emitting layer, a first organic compound layer may be provided between the light-emitting layer and the second electrode. Preferably, the first organic compound layer has a lower minimum excitation triplet energy than the light-emitting layer. Alternatively, a second organic compound layer may be provided between the light-emitting layer and the first electrode. Preferably, the second organic compound layer has a lower minimum excitation triplet energy than the light-emitting layer.

[0110] The organometallic complex according to this embodiment can be used as a constituent material for organic compound layers other than the light-emitting layer constituting the organic light-emitting device of this embodiment. Specifically, it may be used as a constituent material for electron transport layers, electron injection layers, hole transport layers, hole injection layers, hole blocking layers, etc. In this case, the light-emitting color of the organic light-emitting device is not limited to red. More specifically, it may be white light or an intermediate color.

[0111] In addition to the organic compounds according to this embodiment, conventionally known low-molecular-weight and high-molecular-weight hole-injecting or hole-transporting compounds, host compounds, luminescent compounds, electron-injecting or electron-transporting compounds, etc., can be used together as needed. Examples of these compounds are listed below.

[0112] As hole-implantation transport materials, materials with high hole mobility are preferred to facilitate hole injection from the anode and to transport the injected holes to the light-emitting layer. Furthermore, materials with a high glass transition temperature are preferred to suppress deterioration of the film quality, such as crystallization, in the organic light-emitting element. Examples of low-molecular-weight and high-molecular-weight materials with hole-implantation transport properties include triarylamine derivatives, arylcarbazole derivatives, phenylenediamine derivatives, stilbene derivatives, phthalocyanine derivatives, porphyrin derivatives, poly(vinylcarbazole), poly(thiophene), and other conductive polymers. Moreover, the above-mentioned hole-implantation transport materials are also suitably used in electron-blocking layers. Specific examples of compounds used as hole-implantation transport materials are shown below, but are not limited to these.

[0113] [ka]

[0114] Among the hole transport materials listed, HT16 to HT18 can reduce the driving voltage when used in the layer in contact with the anode. HT16 is widely used in organic light-emitting devices. HT2, HT3, HT4, HT5, HT6, HT10, and HT12 may be used in the organic compound layer adjacent to HT16. Furthermore, multiple materials may be used in a single organic compound layer.

[0115] Luminescent materials primarily involved in light emission include fused ring compounds (e.g., fluorene derivatives, naphthalene derivatives, pyrene derivatives, perylene derivatives, tetracene derivatives, anthracene derivatives, rubrene, etc.), quinacridone derivatives, coumarin derivatives, stilbene derivatives, organoaluminum complexes such as tris(8-quinolinolate)aluminum, iridium complexes, platinum complexes, rhenium complexes, copper complexes, europium complexes, ruthenium complexes, and polymer derivatives such as poly(phenylenevinylene) derivatives, poly(fluorene) derivatives, and poly(phenylene) derivatives.

[0116] The following are some specific examples of compounds used as luminescent materials, but of course, they are not the only ones.

[0117] [ka]

[0118] [ka]

[0119] When the luminescent material is a hydrocarbon compound, it is preferable because it can reduce the decrease in luminescence efficiency due to excyplex formation and the decrease in color purity due to changes in the emission spectrum of the luminescent material caused by excyplex formation.

[0120] Hydrocarbon compounds are compounds composed only of carbon and hydrogen, and among the example compounds listed above, these include BD7, BD8, GD5 through GD9, and RD1.

[0121] When the luminescent material is a condensed polycyclic material containing a five-membered ring, it is preferable because its ionization potential is high, making it less susceptible to oxidation and resulting in a highly durable device with a long lifespan. Among the example compounds listed above, BD7, BD8, GD5 to GD9, and RD1 are preferred.

[0122] Examples of light-emitting layer hosts or light-emitting assist materials included in the light-emitting layer include aromatic hydrocarbon compounds or their derivatives, as well as carbazole derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, organoaluminum complexes such as tris(8-quinolinolate)aluminum, and organoberylium complexes.

[0123] The following are specific examples of compounds used as luminescent layer hosts or luminescence assist materials contained in the luminescent layer, but of course, they are not limited to these.

[0124] [ka]

[0125] When the host material is a hydrocarbon compound, the compound of the present invention is more likely to trap electrons and holes, thus greatly enhancing efficiency, which is preferable. A hydrocarbon compound is a compound composed only of carbon and hydrogen, and among the example compounds above, these are EM1 to EM12 and EM16 to EM27.

[0126] As electron-transporting materials, any material capable of transporting electrons injected from the cathode to the light-emitting layer can be arbitrarily selected, taking into consideration the balance with the hole mobility of the hole-transporting material. Examples of materials with electron-transporting properties include oxadiazole derivatives, pyrazine derivatives, triazole derivatives, triazine derivatives, quinoline derivatives, quinoxaline derivatives, phenanthroline derivatives, organoaluminum complexes, and fused ring compounds (e.g., fluorene derivatives, naphthalene derivatives, chrysene derivatives, anthracene derivatives, etc.). Furthermore, the above electron-transporting materials are also suitably used in the hole-blocking layer.

[0127] The following are specific examples of compounds used as electron transport materials, but of course, they are not the only ones.

[0128] [ka]

[0129] Electron-injectable materials can be arbitrarily selected from those that allow for easy electron injection from the cathode, taking into consideration the balance with hole injection properties. Organic compounds include n-type dopants and reducing dopants. Examples include alkali metal compounds such as lithium fluoride, lithium complexes such as lithium quinolinol, benzimidazolidene derivatives, imidazolidene derivatives, fluvalene derivatives, and acridine derivatives.

[0130] It can also be used in combination with the electron transport materials mentioned above.

[0131] [Configuration of organic light-emitting element] An organic light-emitting element is provided on a substrate by forming an insulating layer, a first electrode, an organic compound layer, and a second electrode. A protective layer, a color filter, a microlens, etc., may be provided on the cathode. If a color filter is provided, a planarization layer may be provided between it and the protective layer. The planarization layer can be made of acrylic resin or the like. The same applies when a planarization layer is provided between the color filter and the microlens.

[0132] [substrate] Examples of substrates include quartz, glass, silicon wafers, resins, and metals. The substrate may also be equipped with switching elements such as transistors and wiring, and an insulating layer may be provided on top of them. The insulating layer can be made of any material that allows for the formation of contact holes between it and the first electrode, while ensuring insulation from wiring that is not connected. For example, resins such as polyimide, silicon oxide, and silicon nitride can be used.

[0133] [electrode] A pair of electrodes can be used. The pair of electrodes may be an anode and a cathode. When an electric field is applied in the direction in which the organic light-emitting element emits light, the electrode with the higher potential is the anode, and the other is the cathode. Alternatively, the electrode that supplies holes to the light-emitting layer can be the anode, and the electrode that supplies electrons can be the cathode.

[0134] For the anode, materials with the largest possible work function are preferable. For example, elemental metals such as gold, platinum, silver, copper, nickel, palladium, cobalt, selenium, vanadium, and tungsten, or mixtures containing these, or alloys combining them, as well as metal oxides such as tin oxide, zinc oxide, indium oxide, tin-indium oxide (ITO), and zinc-indium oxide can be used. Conductive polymers such as polyaniline, polypyrrole, and polythiophene can also be used.

[0135] These electrode materials may be used individually or in combination of two or more types. Furthermore, the anode may consist of a single layer or multiple layers.

[0136] When used as a reflective electrode, materials such as chromium, aluminum, silver, titanium, tungsten, molybdenum, or alloys or laminates thereof can be used. It is also possible to use the above materials as a reflective film without serving as an electrode. Furthermore, when used as a transparent electrode, oxide transparent conductive layers such as indium tin oxide (ITO) or indium zinc oxide can be used, but are not limited to these. Photolithography can be used to form the electrodes.

[0137] On the other hand, materials with a small work function are preferred for the cathode. Examples include alkali metals such as lithium, alkaline earth metals such as calcium, and elemental metals or mixtures containing aluminum, titanium, manganese, silver, lead, and chromium. Alternatively, alloys combining these elemental metals can also be used. For example, magnesium-silver, aluminum-lithium, aluminum-magnesium, silver-copper, and zinc-silver can be used. Metal oxides such as indium tin oxide (ITO) can also be used. These electrode materials may be used individually or in combination of two or more. The cathode may also be a single-layer or multi-layer structure. Among these, silver is preferred, and a silver alloy is even more preferred to reduce silver aggregation. The alloy ratio is not important as long as silver aggregation is reduced. For example, the ratio of silver to other metals may be 1:1, 3:1, etc.

[0138] The cathode may be a top-emission element using an oxide conductive layer such as ITO, or a bottom-emission element using a reflective electrode such as aluminum (Al), and is not particularly limited. The method for forming the cathode is not particularly limited, but using DC and AC sputtering methods is more preferable because it provides good film coverage and makes it easier to reduce resistance.

[0139] [Organic compound layer] The organic compound layer may be formed as a single layer or as multiple layers. If there are multiple layers, they may be called a hole injection layer, a hole transport layer, an electron blocking layer, an emissive layer, a hole blocking layer, an electron transport layer, or an electron injection layer, depending on their function. The organic compound layer is mainly composed of organic compounds, but may also contain inorganic atoms and inorganic compounds. For example, it may contain copper, lithium, magnesium, aluminum, iridium, platinum, molybdenum, zinc, etc. The organic compound layer may be placed between the first electrode and the second electrode, or it may be placed in contact with the first electrode and the second electrode.

[0140] [Protective layer] A protective layer may be provided on the cathode. For example, by bonding glass with a desiccant to the cathode, the intrusion of water and other substances into the organic compound layer can be reduced, thereby reducing the occurrence of display defects. In another embodiment, a passivation film such as silicon nitride may be provided on the cathode to reduce the intrusion of water and other substances into the organic compound layer. For example, after forming the cathode, it may be transported to another chamber without breaking the vacuum and a silicon nitride film with a thickness of 2 μm may be formed by the CVD method to serve as a protective layer. A protective layer may also be provided using atomic deposition (ALD) after the film formation by the CVD method. The material of the film formed by the ALD method is not limited, but may be silicon nitride, silicon oxide, aluminum oxide, etc. Silicon nitride may be further formed on the film formed by the ALD method by the CVD method. The film formed by the ALD method may have a thinner film thickness than the film formed by the CVD method. Specifically, it may be 50% or less, or even 10% or less.

[0141] [Color Filter] A color filter may be provided on top of the protective layer. For example, a color filter that takes into account the size of the organic light-emitting element may be provided on a separate substrate and bonded to the substrate on which the organic light-emitting element is provided, or a color filter may be patterned on the protective layer as described above using photolithography technology. The color filter may be made of polymer.

[0142] [Planarization layer] A planarizing layer may be provided between the color filter and the protective layer. The planarizing layer is provided to reduce the unevenness of the layer below. It may also be called a material resin layer without limiting its purpose. The planarizing layer may be composed of an organic compound, which may be low molecular weight or high molecular weight, but high molecular weight is preferred.

[0143] The planarization layer may be provided above or below the color filter, and its constituent materials may be the same or different. Specifically, examples include polyvinylcarbazole resin, polycarbonate resin, polyester resin, ABS resin, acrylic resin, polyimide resin, phenolic resin, epoxy resin, silicone resin, urea resin, etc.

[0144] [Microlens] An organic light-emitting device may have optical elements such as microlenses on its light-emitting side. Microlenses may be made of acrylic resin, epoxy resin, or the like. Microlenses may be used to increase the amount of light extracted from the organic light-emitting device or to control the direction of the extracted light. Microlenses may have a hemispherical shape. If they have a hemispherical shape, among the tangents tangent to the hemisphere, there is a tangent parallel to the insulating layer, and the point of contact between that tangent and the hemisphere is the vertex of the microlens. The vertex of the microlens can be similarly determined in any cross-sectional view. That is, among the tangents tangent to the semicircle of the microlens in the cross-sectional view, there is a tangent parallel to the insulating layer, and the point of contact between that tangent and the semicircle is the vertex of the microlens.

[0145] Furthermore, the midpoint of a microlens can also be defined. In the cross-section of a microlens, a line segment can be imagined from the point where one arc ends to the point where another arc ends, and the midpoint of this line segment can be called the midpoint of the microlens. The cross-section used to determine the vertices and midpoints may be a cross-section perpendicular to the insulating layer.

[0146] [Opposite substrate] A counter substrate may be provided on the planarized layer. The counter substrate is called a counter substrate because it is provided in a position corresponding to the aforementioned substrate. The constituent material of the counter substrate may be the same as that of the aforementioned substrate. The counter substrate may be the second substrate if the aforementioned substrate is referred to as the first substrate.

[0147] [Organic layer] The organic compound layer (hole injection layer, hole transport layer, electron blocking layer, light-emitting layer, hole blocking layer, electron transport layer, electron injection layer, etc.) constituting the organic light-emitting element according to one embodiment of the present invention is formed by the method shown below.

[0148] The organic compound layer constituting the organic light-emitting element according to one embodiment of the present invention can be formed using a dry process such as vacuum deposition, ionization deposition, sputtering, or plasma deposition. Alternatively, instead of a dry process, a wet process can be used in which the layer is formed by dissolving the compound in a suitable solvent and applying a known coating method (e.g., spin coating, dipping, casting, LB method, inkjet method, etc.).

[0149] When layers are formed using methods such as vacuum deposition or solution coating, crystallization is less likely to occur, resulting in excellent stability over time. Furthermore, when forming films using coating methods, it is possible to combine the film with an appropriate binder resin.

[0150] Examples of the binder resins mentioned above include, but are not limited to, polyvinylcarbazole resin, polycarbonate resin, polyester resin, ABS resin, acrylic resin, polyimide resin, phenolic resin, epoxy resin, silicone resin, and urea resin.

[0151] Furthermore, these binder resins may be used individually as homopolymers or copolymers, or as a mixture of two or more types. Additionally, known additives such as plasticizers, antioxidants, and UV absorbers may be used in combination as needed.

[0152] [Pixel circuit] The light-emitting device may have a pixel circuit connected to a light-emitting element. The pixel circuit may be an active-matrix type that independently controls the light emission of a first light-emitting element and a second light-emitting element. The active-matrix type circuit may be voltage-programmed or current-programmed. The drive circuit has a pixel circuit for each pixel. The pixel circuit may have a light-emitting element, a transistor that controls the light emission brightness of the light-emitting element, a transistor that controls the light emission timing, a capacitor that holds the gate voltage of the transistor that controls the light emission brightness, and a transistor for connecting to GND without going through the light-emitting element.

[0153] The light-emitting device has a display area and a peripheral area arranged around the display area. The display area has a pixel circuit, and the peripheral area has a display control circuit. The mobility of the transistors constituting the pixel circuit may be smaller than the mobility of the transistors constituting the display control circuit.

[0154] The slope of the current-voltage characteristics of the transistors constituting the pixel circuit can be smaller than the slope of the current-voltage characteristics of the transistors constituting the display control circuit. The slope of the current-voltage characteristics can be measured using the so-called Vg-Ig characteristic.

[0155] The transistors that make up the pixel circuit are transistors connected to light-emitting elements, such as the first light-emitting element.

[0156] [Pixels] The organic light-emitting device has multiple pixels. Each pixel has subpixels that emit light of a different color from the others. The subpixels may each have, for example, RGB light-emitting colors.

[0157] A pixel emits light in a region also called the pixel aperture. This region is the same as the first region. The pixel aperture may be 15 μm or less, or 5 μm or more. More specifically, it may be 11 μm, 9.5 μm, 7.4 μm, 6.4 μm, etc.

[0158] The distance between subpixels may be 10 μm or less, specifically 8 μm, 7.4 μm, or 6.4 μm.

[0159] Pixels can take on known arrangements in a plan view. For example, they may be in a stripe arrangement, delta arrangement, pentile arrangement, or Bayer arrangement. The shape of subpixels in a plan view may be any known shape. For example, rectangles, rhombuses, hexagons, etc. Of course, even if it is not a precise shape, if it is close to a rectangle, it is included in the category of rectangles. The shape of subpixels and the pixel arrangement can be used in combination.

[0160] [Applications of the organic light-emitting element according to one embodiment of the present invention] An organic light-emitting element according to one embodiment of the present invention can be used as a component of a display device or lighting device. Other applications include exposure light sources for electrophotographic image forming apparatuses, backlights for liquid crystal display devices, and light-emitting devices with a color filter in a white light source.

[0161] The display device may also be an image information processing device that has an image input unit for receiving image information from an area CCD, linear CCD, memory card, etc., an information processing unit for processing the input information, and displays the input image on the display unit.

[0162] Furthermore, the display unit of the imaging device or inkjet printer may have a touch panel function. The driving method for this touch panel function may be infrared, capacitive, resistive, or electromagnetic induction, and is not particularly limited. The display device may also be used as the display unit of a multifunction printer.

[0163] Next, the display device according to this embodiment will be described with reference to the drawings.

[0164] Figure 2 is a schematic cross-sectional view showing an example of a display device having an organic light-emitting element and a transistor connected to this organic light-emitting element. The transistor is an example of an active element. The transistor may also be a thin-film transistor (TFT).

[0165] Figure 2(a) shows an example of a pixel, which is a component of the display device according to this embodiment. The pixel has sub-pixels 10. The sub-pixels are divided into 10R, 10G, and 10B based on their light emission. The light emission color may be distinguished by the wavelength emitted from the light-emitting layer, or the light emitted from the sub-pixel may be selectively transmitted or color-converted by a color filter or the like. Each sub-pixel has a reflective electrode 2 which is a first electrode, an insulating layer 3 covering the end of the reflective electrode 2, an organic compound layer 4 covering the first electrode and the insulating layer, a transparent electrode 5, a protective layer 6, and a color filter 7 on an interlayer insulating layer 1.

[0166] The interlayer insulating layer 1 may have transistors and capacitive elements placed in the layer below or inside it. The transistor and the first electrode may be electrically connected via a contact hole or the like (not shown).

[0167] The insulating layer 3 is also called the bank or pixel isolation layer. It covers the edge of the first electrode and surrounds the first electrode. The portion without the insulating layer is in contact with the organic compound layer 4 and becomes the light-emitting region.

[0168] The organic compound layer 4 includes a hole injection layer 41, a hole transport layer 42, a first light-emitting layer 43, a second light-emitting layer 44, and an electron transport layer 45.

[0169] The second electrode 5 may be a transparent electrode, a reflective electrode, or a semi-transparent electrode.

[0170] The protective layer 6 reduces the penetration of moisture into the organic compound layer. Although the protective layer is shown as a single layer, it may consist of multiple layers. Each layer may contain an inorganic compound layer and an organic compound layer.

[0171] The color filters 7 are classified into 7R, 7G, and 7B according to their color. The color filters may be formed on a planarization film (not shown). The color filters may also have a resin protective layer (not shown). Alternatively, the color filters may be formed on a protective layer 6, or they may be bonded together after being placed on an opposing substrate such as a glass substrate.

[0172] The display device 100 in Figure 2(b) shows an organic light-emitting element 26 and a TFT 18 as an example of a transistor. A substrate 11 made of glass, silicon, or the like is provided, with an insulating layer 12 on top of it. An active element 18 such as a TFT is placed on the insulating layer, and the gate electrode 13, gate insulating film 14, and semiconductor layer 15 of the active element are arranged therein. The TFT 18 is also composed of a semiconductor layer 15, a drain electrode 16, and a source electrode 17. An insulating film 19 is provided on top of the TFT 18. The anode 21 and the source electrode 17 that constitute the organic light-emitting element 26 are connected via a contact hole 20 provided in the insulating film.

[0173] Note that the method of electrical connection between the electrodes (anode, cathode) included in the organic light-emitting element 26 and the electrodes (source electrode, drain electrode) included in the TFT is not limited to the configuration shown in Figure 2(b). In other words, it is sufficient for either the anode or cathode to be electrically connected to either the TFT source electrode or the drain electrode. TFT refers to a thin-film transistor.

[0174] In the display device 100 shown in Figure 2(b), the organic compound layer is depicted as a single layer, but the organic compound layer 22 may consist of multiple layers. A first protective layer 24 and a second protective layer 25 are provided on the cathode 23 to reduce the degradation of the organic light-emitting element.

[0175] In the display device 100 shown in Figure 2(b), a transistor is used as the switching element, but other switching elements may be used instead.

[0176] Furthermore, the transistor used in the display device 100 in Figure 2(b) is not limited to a transistor using a single-crystal silicon wafer, but may also be a thin-film transistor having an active layer on an insulating surface of the substrate. Examples of the active layer include non-single-crystal silicon such as single-crystal silicon, amorphous silicon, and microcrystalline silicon, and non-single-crystal oxide semiconductors such as indium zinc oxide and indium gallium zinc oxide. Thin-film transistors are also called TFT elements.

[0177] The transistors included in the display device 100 in Figure 2(b) may be formed within a substrate such as a Si substrate. Here, "formed within a substrate" means that the transistors are manufactured by processing the substrate itself, such as a Si substrate. In other words, having transistors within a substrate can be seen as the substrate and transistors being formed as a single unit.

[0178] The organic light-emitting element according to this embodiment has its luminescence controlled by a TFT, which is an example of a switching element, and by providing multiple organic light-emitting elements on the surface, an image can be displayed using the luminescence of each element. The switching element according to this embodiment is not limited to a TFT, but may also be a transistor made of low-temperature polysilicon, or an active matrix driver formed on a substrate such as a Si substrate. "On the substrate" can also mean "within the substrate." Whether to provide a transistor within the substrate or to use a TFT is selected depending on the size of the display area; for example, if the size is about 0.5 inches, it is preferable to provide the organic light-emitting element on a Si substrate.

[0179] Figure 3 is a schematic diagram showing an example of a display device according to this embodiment. The display device 1000 may have a touch panel 1003, a display panel 1005, a frame 1006, a circuit board 1007, and a battery 1008 between an upper cover 1001 and a lower cover 1009. Flexible printed circuits FPCs 1002 and 1004 are connected to the touch panel 1003 and the display panel 1005. Transistors are printed on the circuit board 1007. The battery 1008 may not be provided if the display device is not a portable device, or it may be provided in a different location even if it is a portable device.

[0180] The display device according to this embodiment may have a color filter having red, green, and blue colors. The color filter may have the red, green, and blue colors arranged in a delta array.

[0181] The display device according to this embodiment may be used in the display unit of a mobile terminal. In that case, it may have both display and operation functions. Examples of mobile terminals include smartphones and other mobile phones, tablets, and head-mounted displays.

[0182] The display device according to this embodiment may be used in the display unit of an imaging device having an optical unit with multiple lenses and an image sensor that receives light that has passed through the optical unit. The imaging device may have a display unit that displays information acquired by the image sensor. Furthermore, the display unit may be a display unit exposed to the outside of the imaging device or a display unit located inside the viewfinder. The imaging device may be a digital camera or a digital video camera.

[0183] Figure 4(a) is a schematic diagram showing an example of an imaging device according to this embodiment. The imaging device 1100 may include a viewfinder 1101, a rear display 1102, an operation unit 1103, and a housing 1104. The viewfinder 1101 may have a display device according to this embodiment. In that case, the display device may display not only the image to be captured, but also environmental information, imaging instructions, etc. Environmental information may include the intensity of ambient light, the direction of ambient light, the speed at which the subject is moving, the possibility of the subject being obscured by an obstacle, etc.

[0184] Since the optimal timing for imaging is very short, it is best to display the information as quickly as possible. Therefore, it is preferable to use a display device using the organic light-emitting element of the present invention, because organic light-emitting elements have a fast response speed. Display devices using organic light-emitting elements can be used more suitably than liquid crystal display devices, which require a fast display speed.

[0185] The imaging device 1100 has an optical section (not shown). The optical section has multiple lenses that form an image on the image sensor housed in the housing 1104. The focus can be adjusted by adjusting the relative positions of the multiple lenses. This operation can also be performed automatically. The imaging device may also be called a photoelectric converter. The photoelectric converter may not capture images sequentially, but may include imaging methods such as detecting the difference from the previous image or extracting from an image that is always being recorded.

[0186] Figure 4(b) is a schematic diagram showing an example of an electronic device according to this embodiment. The electronic device 1200 has a display unit 1201, an operation unit 1202, and a housing 1203. The housing 1203 may have a circuit, a printed circuit board having the circuit, a battery, and a communication unit. The operation unit 1202 may be a button or a touch panel type response unit. The operation unit may also be a biometric recognition unit that recognizes fingerprints to unlock or otherwise perform actions. An electronic device having a communication unit can also be called a communication device. The electronic device may further have a camera function by including a lens and an image sensor. Images captured by the camera function are displayed on the display unit. Examples of electronic devices include smartphones and laptop computers.

[0187] Figure 5 is a schematic diagram showing an example of a display device according to this embodiment. Figure 5(a) is a display device such as a television monitor or a PC monitor. The display device 1300 has a frame 1301 and a display unit 1302. The display unit 1302 may use the light-emitting device according to this embodiment.

[0188] It has a frame 1301 and a base 1303 that supports the display unit 1302. The base 1303 is not limited to the form shown in Figure 5(a). The bottom edge of the frame 1301 may also serve as the base.

[0189] Furthermore, the frame 1301 and the display section 1302 may be curved. Their radius of curvature may be between 5000 mm and 6000 mm.

[0190] Figure 5(b) is a schematic diagram showing another example of the display device according to this embodiment. The display device 1310 in Figure 5(b) is configured to be foldable and is a so-called foldable display device. The display device 1310 has a first display unit 1311, a second display unit 1312, a housing 1313, and a bending point 1314. The first display unit 1311 and the second display unit 1312 may have light-emitting devices according to this embodiment. The first display unit 1311 and the second display unit 1312 may be a single display device without seams. The first display unit 1311 and the second display unit 1312 can be separated at a bending point. The first display unit 1311 and the second display unit 1312 may each display different images, or the first and second display units may together display a single image.

[0191] Figure 6(a) is a schematic diagram showing an example of a lighting device according to this embodiment. The lighting device 1400 may include a housing 1401, a light source 1402, a circuit board 1403, an optical film 1404, and a light diffusion section 1405. The light source may have an organic light-emitting element according to this embodiment. The optical filter may be a filter that improves the color rendering of the light source. The light diffusion section can effectively diffuse the light from the light source, such as for lighting up, and deliver light over a wide area. The optical filter and light diffusion section may be provided on the light-emitting side of the lighting. A cover may be provided on the outermost part as needed.

[0192] The lighting device is, for example, a device for illuminating a room. The lighting device may emit white light, cool white light, or any other color from blue to red. It may have a dimming circuit to adjust the brightness of these lights. The lighting device may have the organic light-emitting element of the present invention and a power supply circuit connected thereto. The power supply circuit is a circuit that converts AC voltage to DC voltage. White light has a color temperature of 4200K, and cool white light has a color temperature of 5000K. The lighting device may have a color filter.

[0193] Furthermore, the lighting device according to this embodiment may have a heat dissipation section. The heat dissipation section releases heat from inside the device to the outside, and examples include metals with high specific heat, liquid silicon, etc.

[0194] Figure 6(b) is a schematic diagram of an automobile, which is an example of a mobile body according to this embodiment. The automobile has a taillight, which is an example of a lighting device. The automobile 1500 has a taillight 1501, and may be configured to illuminate when the brakes are applied or the like.

[0195] The tail lamp 1501 may have an organic light-emitting element according to this embodiment. The tail lamp may have a protective member to protect the organic EL element. The protective member has a reasonably high strength and can be made of any transparent material, but it is preferably made of polycarbonate or the like. A frangic acid derivative, an acrylonitrile derivative, or the like may be mixed with the polycarbonate.

[0196] The automobile 1500 may have a body 1503 and windows 1502 attached thereto. The windows may be transparent displays, unless they are windows for checking the front and rear of the automobile. The transparent displays may have organic light-emitting elements according to this embodiment. In this case, the constituent materials such as electrodes of the organic light-emitting element are made of transparent members.

[0197] The mobile body according to this embodiment may be a ship, aircraft, drone, etc. The mobile body may have a body and a lighting device provided on the body. The lighting device may emit light to indicate the position of the body. The lighting device has an organic light-emitting element according to this embodiment.

[0198] Referencing Figure 7, examples of applications of the display devices of each embodiment described above will be explained. The display device can be applied to systems that can be worn as wearable devices such as smart glasses, HMDs, and smart contacts. The imaging display device used in such applications has an imaging device capable of photoelectric conversion of visible light and a display device capable of emitting visible light.

[0199] Figure 7(a) illustrates a pair of glasses 1600 (smart glasses) according to one application example. An imaging device 1602, such as a CMOS sensor or SPAD, is provided on the front surface of the lens 1601 of the glasses 1600. In addition, the display devices of each embodiment described above are provided on the back surface of the lens 1601.

[0200] The eyeglasses 1600 further include a control device 1603. The control device 1603 functions as a power supply that provides power to the imaging device 1602 and the display device according to each embodiment. The control device 1603 also controls the operation of the imaging device 1602 and the display device. The lens 1601 has an optical system formed therein for focusing light onto the imaging device 1602.

[0201] Figure 7(b) illustrates a pair of glasses 1610 (smart glasses) relating to one application example. The glasses 1610 have a control device 1612, which is equipped with an imaging device equivalent to an imaging device 1602 and a display device. The lens 1611 has an optical system formed therein for projecting light emitted from the imaging device and the display device within the control device 1612, and an image is projected onto the lens 1611. The control device 1612 functions as a power supply to provide power to the imaging device and the display device, and also controls the operation of the imaging device and the display device. The control device may have a gaze detection unit that detects the wearer's gaze. Gaze detection may use infrared light. The infrared light emitter emits infrared light towards the eyeball of the user who is fixating on the displayed image. The imaging unit, which has a photodetector, detects the reflected light from the eyeball of the emitted infrared light, thereby obtaining an image of the eyeball. By having a reduction means that reduces the light from the infrared light emitter to the display unit in planar view, the degradation of image quality is reduced.

[0202] The user's gaze towards the displayed image is detected from an image of the eyeball obtained by imaging with infrared light. Any known method can be applied to gaze detection using an image of the eyeball. For example, a gaze detection method based on the Purkinje image obtained by the reflection of the irradiated light from the cornea can be used.

[0203] More specifically, gaze detection processing is performed based on the pupil-corneal reflection method. Using the pupil-corneal reflection method, a gaze vector representing the orientation (rotation angle) of the eyeball is calculated based on the pupil image and Purkinje image contained in the captured image of the eyeball, thereby detecting the user's gaze.

[0204] A display device according to one embodiment of the present invention includes an imaging device having a light-receiving element, and may control the display image of the display device based on the user's gaze information from the imaging device.

[0205] Specifically, the display device determines a first field of view that the user is fixated on, and a second field of view other than the first field of view, based on gaze information. The first and second field of view may be determined by the control device of the display device, or they may be determined by an external control device and received by the display device. Within the display area of ​​the display device, the display resolution of the first field of view may be controlled to be higher than the display resolution of the second field of view. In other words, the resolution of the second field of view may be lower than that of the first field of view.

[0206] Furthermore, the display area has a first display area and a second display area different from the first display area, and based on gaze information, the area with higher priority is determined from the first display area and the second display area. The first and second view areas may be determined by the control device of the display device, or they may be determined by an external control device and received. The resolution of the high-priority area may be controlled to be higher than the resolution of the areas other than the high-priority area. In other words, the resolution of areas with relatively lower priority may be lowered.

[0207] AI may be used to determine the primary field of view and high-priority areas. The AI ​​may be a model configured to estimate the angle of gaze and the distance to the target object at the end of the line of sight from the image of the eye, using the image of the eye and the direction the eye was actually looking in that image as training data. The AI ​​program may be installed in the display device, the imaging device, or an external device. If installed in an external device, it will be transmitted to the display device via communication.

[0208] In the case of performing display control based on visual recognition detection, the present invention can be preferably applied to smart glasses further comprising an imaging device that images the outside. The smart glasses can display captured external information in real time.

[0209] As described above, by using the device using the organic light-emitting element according to the present embodiment, display with good image quality that is stable even for long-time display can be achieved. [Examples]

[0210] The organometallic complex according to the present invention can be synthesized, for example, by the following synthesis method. The following shows the synthesis of exemplary compound A-1 as an example.

[0211] [Chemical Formula]

[0212] Examples will be described below. Of course, the present invention is not limited to these.

[0213] [Example 1] <Synthesis of Exemplary Compound A-1> Exemplary compound A-1 was synthesized according to the following procedure.

[0214] [Chemical Formula]

[0215] Under a nitrogen atmosphere, 2.19 g of 2-(methoxycarbonyl)phenylboronic acid, 2.0 g of 4-chlorobenzo[f]isoquinoline, 0.54 g of tetrakistriphenylphosphine palladium, 100 mL of 1,4-dioxane, 30 mL of pure water, and 3.00 g of sodium carbonate were added into a 200 mL eggplant flask. This solution was heated from room temperature to 90°C and stirred for 12 hours. Chloroform and water were added, and the organic layer was extracted. Magnesium sulfate was added to the organic layer, followed by filtration. After concentration, column purification was performed using a hexane solution containing 10% ethyl acetate. The obtained liquid was concentrated to give 1.61 g of Intermediate 1. The structure is1 Identification was performed using 1H-NMR and GC-MS.

[0216] [ka]

[0217] Under a nitrogen atmosphere, 1.5 g of intermediate 1, 50 mL of anhydrous THF, and 40 mL of 1.06 M methylmagnesium bromide / tetrahydrofuran solution were added to a 300 mL round-bottom flask. This solution was stirred at room temperature for 12 hours. The reaction was stopped with saturated aqueous ammonium chloride solution. Chloroform and water were added, and magnesium sulfate was added to the extracted organic layer, which was then filtered. After concentrating the solvent, it was column-fired using a hexane solution containing 10% ethyl acetate. The resulting liquid was concentrated to obtain 1.11 g of intermediate 2. The structure is 1 Identification was performed using 1H-NMR and GC-MS.

[0218] [ka]

[0219] Under a nitrogen atmosphere, 1.0 g of intermediate 2 and 10 mL of trifluoromethanesulfonic acid were added to a 100 mL round-bottom flask. The mixture was then stirred at room temperature for 1 hour. Dichloromethane and water were added, and magnesium sulfate was added to the extracted organic layer. The mixture was filtered. Concentration of the solvent yielded 0.85 g of intermediate 3. Its structure is... 1 Identification was performed using 1H-NMR and GC-MS.

[0220] [ka]

[0221] Under a nitrogen atmosphere, 0.80 g of intermediate 3, 0.48 g of iridium chloride trihydrate, 30 mL of 2-ethoxyethanol, and 10 mL of pure water were added to a 200 mL round-bottom flask. This solution was heated from room temperature to 120°C and stirred for 20 hours. Water was added, and the precipitated solid was filtered. The filtered solid was washed with methanol and hexane to obtain 1.00 g of intermediate 4.

[0222] [ka]

[0223] Under a nitrogen atmosphere, 0.5 g of intermediate 4, g of dipivaloylmethane, mL of 2-ethoxyethanol, and g of sodium carbonate were added to a 100 mL round-bottom flask. This solution was heated from room temperature to 120°C and stirred for 20 hours. Water was added, and the precipitated solid was filtered. The filtered solid was washed with methanol to obtain 0.47 g of exemplary compound A-1.

[0224] NMR measurements confirmed that the obtained compound was example compound A-1, as the ratio of peak integral values ​​closely matched that of the structure. The NMR spectrum measurement results are shown below.

[0225] 1H-NMR (deuterated chloroform) δ (ppm): 7.20 (t, 1H), 6.99-6.83 (m, 5H), 6.74 (d, 1H), 6.72-6.65 (m, 2H), 4 .45(sep, 2H), 3.69(s, 3H), 3.25(sep, 1H), 2.28(s, 3H), 1.62(d, 6H), 1.42-1.02(d, br, 12H)

[0226] [Example 2] (Evaluation of luminescence characteristics and luminescence efficiency) Toluene solution (1.0 × 10⁻⁶) obtained by dissolving exemplary compound A-1 obtained in Example 1. -5M) was adjusted, and the emission spectrum and quantum yield were measured. From the obtained results, the emission wavelength, full width at half maximum (FWHM) of the emission spectrum, chromaticity coordinates, and emission quantum yield of each iridium complex were calculated and listed in Table 3. Similarly, the measurement results of Compound A and Compound B are shown as comparative compounds. The full width at half maximum of the emission spectrum refers to the peak width of the emission spectrum. Since the width was measured at a position approximately half of the maximum emission intensity, it is described as the full width at half maximum.

[0227]

Table 3

[0228] [Example 3] <Synthesis of Exemplary Compound A-52> Exemplary Compound A-52 was synthesized according to the following procedure.

[0229]

Chemical Formula

[0230] Under a nitrogen atmosphere, 0.5 g (1.90 mmol) of NIQ-Cl, 0.37 g (2.28 mmol) of 2-acetoxyphenylboronic acid, 0.11 g (0.095 mmol) of tetrakistriphenylphosphinepalladium, 15 mL of 1,4-dioxane, 5 mL of pure water, and 0.40 g (3.80 mmol) of sodium carbonate were added into a 100 mL eggplant-shaped flask. The solution was heated from room temperature to 110°C and stirred for 6 hours. Chloroform and water were added, and the organic layer was extracted. Magnesium sulfate was added to the organic layer, followed by filtration. After concentration, column purification was performed to obtain 0.56 g of Intermediate b-1.

[0231] Next, in a nitrogen atmosphere, 0.5 g (1.44 mmol) of intermediate b-1 and 20 mL of anhydrous THF were added to a 100 mL round-bottom flask and stirred in an ice bath. 4.1 mL (4.32 mmol) of 1.06 M methylmagnesium bromide / tetrahydrofuran solution was added dropwise, and the solution was heated to room temperature and stirred for 12 hours. The reaction was stopped with saturated ammonium chloride aqueous solution. Chloroform and water were added, and magnesium sulfate was added to the extracted organic layer, which was then filtered. After concentrating the solvent, column purification was performed to obtain 0.26 g of intermediate b-2.

[0232] Under a nitrogen atmosphere, 0.2 g (0.56 mmol) of intermediate b-2 was suspended in 5 mL of trifluoromethanesulfonic acid in a 100 mL round-bottom flask and stirred at 120 °C for 5 hours. After the reaction was complete, the mixture was neutralized with aqueous sodium hydroxide solution while stirring in an ice bath, chloroform and water were added, and magnesium sulfate was added to the extracted organic layer, which was then filtered. After concentration, column purification was performed to obtain 0.17 g of intermediate b-3.

[0233] In a nitrogen atmosphere, 0.15 g (0.44 mmol) of intermediate b-3, 1.5 mg (0.44 mmol) of iridium chloride trihydrate, 10 mL of 2-ethoxyethanol, and 5 mL of pure water were mixed, and the solution was stirred at 120°C for 20 hours. Water was added, and the precipitated solid was filtered. The filtered solid was washed with methanol and hexane to obtain 0.15 g of intermediate b-4. This intermediate b-4 was mixed with 10 mL of 2-ethoxyethanol, and 199 mg of diketone b-5 and 78 mg of sodium carbonate were added, and the mixture was stirred at 120°C for 5 hours. Water was added, and the precipitated solid was filtered. The filtered solid was washed with methanol to obtain 0.10 g of exemplary compound A-52.

[0234] [Example 4] <Synthesis of example compound A-53> Exemplary compound A-53 was synthesized using the following procedure.

[0235] [ka]

[0236] In a nitrogen atmosphere, 0.5 g (1.44 mmol) of intermediate b-1 from Example 3, 437 mg (2.88 mmol) of cesium fluoride, and 20 mL of anhydrous 1,4-dioxane were mixed in a 100 mL round-bottom flask and stirred. 410 mg (2.88 mmol) of (trifluoromethyl)trimethylsilane was added dropwise, and the solution was stirred at room temperature for 3 hours. Saturated sodium hydroxide aqueous solution was added and stirred at 50°C for 30 minutes. Distilled water and chloroform were added to the residue, magnesium sulfate was added to the extracted organic layer, and the mixture was filtered. The solvent was concentrated to obtain 0.54 g of intermediate c-1.

[0237] Under a nitrogen atmosphere, 0.50 g (1.20 mmol) of intermediate c-1 was suspended in 5 mL of trifluoromethanesulfonic acid in a 100 mL round-bottom flask and stirred at 120°C for 5 hours. After the reaction was complete, the mixture was neutralized with aqueous sodium hydroxide solution while stirring in an ice bath, chloroform and water were added, and magnesium sulfate was added to the extracted organic layer, which was then filtered. After concentration, column purification was performed to obtain 0.33 g of intermediate c-2.

[0238] In a nitrogen atmosphere, 0.25 g (0.63 mmol) of intermediate c-2, 90 mg (0.30 mmol) of iridium chloride trihydrate, 20 mL of 2-ethoxyethanol, and 7 mL of pure water were mixed, and the solution was stirred at 120°C for 20 hours. Water was added, and the precipitated solid was filtered. The filtered solid was washed with methanol and hexane to obtain 0.21 g of intermediate c-3. This intermediate c-3 was mixed with 10 mL of 2-ethoxyethanol, and 177 mg of diketone b-5 and 88 mg of sodium carbonate were added, and the mixture was stirred at 120°C for 5 hours. Water was added, and the precipitated solid was filtered. The filtered solid was washed with methanol to obtain 0.10 g of exemplary compound A-53.

[0239] [Example 5] (Evaluation of luminescence characteristics and luminescence efficiency) Exemplary compound A-52 obtained in Example 3 and exemplary compound A-53 obtained in Example 4 were dissolved in toluene (1.0 × 10⁻⁶). -5 M) The emission spectrum and quantum yield were measured in the same manner as in Example 2. The results obtained are shown in Table 4.

[0240] [Table 4]

[0241] As described above, the organometallic complex according to the present invention can achieve both a small full width at half maximum of the emission spectrum and high emission quantum efficiency. [Explanation of Symbols]

[0242] Single-layer insulating layer 2 reflective electrode 3. Insulating layer 4 Organic compound layer 5 Transparent electrode 6 Protective layer 7 Color Filters 10 subpixels 11 circuit boards 12 Insulating layer 13 gates 14 Gate insulating film 15 Semiconductor layer 16 Drain electrode 17 Source electrodes 18 Thin-film transistors 19 Insulating film 20 contact holes 21 Lower electrode 22 Organic compound layer 23 Upper electrode 24 First protective layer 25 Second protective layer 26 Organic light-emitting diodes 100 display device 1000 display devices 1001 Top cover 1002 Flexible Printed Circuits 1003 Touch Panel 1004 Flexible Printed Circuit 1005 Display Panel 1006 Frame 1007 Circuit board 1008 Battery 1009 Lower cover 1100 Imaging device 1101 Viewfinder 1102 Rear display 1103 Operation section 1104 cabinet 1200 Electronic equipment 1201 Display section 1202 Operation unit 1203 enclosure 1300 display device 1301 Picture frame 1302 Display section 1303 Base 1310 Display device 1311 First display section 1312 Second display section 1313 cabinet 1314 Inflection point 1400 Lighting devices 1401 cabinet 1402 Light source 1403 Circuit board 1404 Optical Film 1405 Light Diffusion Section 1500 cars 1501 Taillight 1502 Window

Claims

1. An organometallic complex characterized by being represented by the following formula (1). ML ｍ 5 ｎ L'' ｌ ((1) In equation (1), M represents Ir, and L ｍ , L' ｎ , L'' ｌ Each of these represents a different ligand. m is an integer from 1 to 3, n is an integer from 0 to 2, and l is an integer from 0 to 2, so m + n + l = 3. ML ｍ This structure is represented by the following general formula (2). 【Chemistry 1】 In general formula (2), R １１ to R １４ are each independently selected from a hydrogen atom, a deuterium atom, a fluorine atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, and a silyl group. The substituent that said alkyl group has may be a deuterium atom or a fluorine atom. X is selected from CRR' and SiRR'. R and R' are independently selected from substituted or unsubstituted alkyl groups having 1 to 10 carbon atoms and fluorine atoms, respectively. The substituents on the alkyl group may be deuterium atoms or fluorine atoms. Y １ Y ６ The carbon atom is an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms. ３ Y ６ Two of these adjacent atoms may bond together to form a benzene ring. ML' ｎ and ML'' ｌ These are independently selected from equation (4) or (5) below. 【Chemistry 2】 In equations (4) and (5), R ３１ ~R ３８ and R ４１ ~R ４３ Each of these atoms is independently selected from a hydrogen atom, a deuterium atom, a fluorine atom, and an alkyl group having 1 to 10 carbon atoms, whether substituted or unsubstituted. The substituents on the alkyl group may be deuterium atoms or fluorine atoms.

2. The organometallic complex according to claim 1, characterized in that the organometallic complex is represented by the following formula (3). 【Transformation 3】 In equation (3), R ２１ ~R ２６ The substituents are independently selected from a hydrogen atom, a deuterium atom, a fluorine atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, and a silyl group. The substituents on the alkyl group may be a deuterium atom or a fluorine atom. X is selected from CRR' and SiRR'. R and R' are independently selected from substituted or unsubstituted alkyl groups having 1 to 10 carbon atoms and fluorine atoms, respectively. The substituents on the alkyl group may be deuterium atoms or fluorine atoms. Y ７ Y １２ This is a carbon atom having an alkyl group with 1 to 10 carbon atoms or an aryl group with 6 to 10 carbon atoms.

3. The organometallic complex according to claim 1 or 2, characterized in that X is CRR', and R and R' are each independently selected from substituted or unsubstituted alkyl groups having 1 to 10 carbon atoms.

4. The organometallic complex according to any one of claims 1 to 3, characterized in that the full width at half maximum of the emission spectrum is 40 nm or less.

5. In equation (1), R １１ ~R １４ The organometallic complex according to claim 1, characterized in that each of the hydrogen atom, the deuterium atom, and the aryl group is independently selected.

6. An organic light-emitting element comprising a first electrode, a second electrode, and an organic compound layer disposed between the first electrode and the second electrode, wherein the organic compound layer has an organometallic complex according to any one of claims 1 to 5.

7. The organic light-emitting element according to claim 6, wherein the organic compound layer has a light-emitting layer, and the light-emitting layer further comprises the organometallic complex and a first organic compound having a lower minimum excitation singlet energy greater than that of the organometallic complex.

8. The organic light-emitting element according to claim 7, wherein the light-emitting layer has a second organic compound different from the first organic compound, and the lowest excited triplet energy of the second organic compound is lower than the lowest excited triplet energy of the first organic compound and higher than the lowest excited triplet energy of the organometallic complex.

9. The organic light-emitting element according to claim 7 or 8, wherein the organic compound layer has a first organic compound layer between the light-emitting layer and the second electrode, and the lowest excitation triplet energy of the first organic compound layer is higher than the lowest excitation triplet energy of the light-emitting layer.

10. The organic light-emitting element according to claim 9, characterized in that the first organic compound layer is composed of a hydrocarbon compound.

11. The organic light-emitting element according to any one of claims 7 to 10, wherein the organic compound layer has a second organic compound layer between the light-emitting layer and the first electrode, and the lowest excitation triplet energy of the second organic compound layer is higher than the lowest excitation triplet energy of the light-emitting layer.

12. The organic light-emitting element according to claim 11, characterized in that the second organic compound layer is composed of a hydrocarbon compound.

13. A display device having a plurality of pixels, wherein at least one of the plurality of pixels is an organic light-emitting element according to any one of claims 6 to 12, and a transistor connected to the organic light-emitting element.

14. It comprises an optical unit having multiple lenses, an image sensor that receives light that has passed through the optical unit, and a display unit that displays the image captured by the image sensor. The imaging device is characterized in that the display unit has an organic light-emitting element as described in any one of claims 6 to 12.

15. An electronic device comprising: a display unit having an organic light-emitting element as described in any one of claims 6 to 12; a housing on which the display unit is provided; and a communication unit provided in the housing for communicating with the outside.

16. A lighting device comprising a light source having an organic light-emitting element as described in any one of claims 6 to 12, and a light-diffusing section or optical filter that transmits light emitted by the light source.

17. A mobile body comprising a lamp having an organic light-emitting element as described in any one of claims 6 to 12, and a body on which the lamp is provided.

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