Organic compounds and organic light-emitting elements

Abstract

To provide an organic light-emitting device that has high color purity and is excellent in luminous efficacy.SOLUTION: An organic light-emitting device has a first electrode, a second electrode, a light-emitting layer arranged between the first electrode and the second electrode. The light-emitting layer includes a dopant material and a host material. The dopant material is a specific iridium complex. The host material is hydrocarbon.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention is organic compound and organic Light-emitting element Regarding. [Background technology]

[0002] An organic light-emitting element (hereinafter sometimes referred to as an "organic electroluminescent element" or "organic EL element") is an electronic element having a pair of electrodes and an organic compound layer placed between these electrodes. By injecting electrons and holes from this pair of electrodes, excitons of the light-emitting organic compound in the organic compound layer are generated, and when these excitons return to the ground state, the organic light-emitting element emits light. Recent advances in organic light-emitting devices are remarkable, and their characteristics include low drive voltage, diverse emission wavelengths, fast response, and the ability to make light-emitting devices thinner and lighter. Regarding the improvement of the efficiency of light-emitting devices, examples include devices using high-efficiency materials such as phosphorescent materials. Patent Document 1 describes the following compounds A-1 and A-2.

[0003] [ka] [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] U.S. Patent Application Publication No. 2019 / 0252619 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] When compounds A-1 and A-2 described in Patent Document 1 are used in the light-emitting layer of an organic light-emitting device, there is room for improvement in luminescence efficiency. The present invention has been made in view of the above problems, and its objective is to provide an organic light-emitting element and an organic compound that have high color purity and excellent luminous efficiency. Another objective of the present invention is to provide an organic light-emitting element that has excellent luminous efficiency and drive durability characteristics. [Means for solving the problem]

[0008] Book The organic compound of the invention is characterized by being represented by the following general formula [1] or [2].

[0009] [ka] In formulas [1] to [2], R1 to R 12 , R 21 ~R 32 Each of these is independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heteroaryloxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted silyl group, and a substituted or unsubstituted amino group. However, R1 to R 12 At least one of R 21 ~R 32 At least one of them is a tertiary alkyl group having 4 or more carbon atoms. m represents an integer between 1 and 3 (inclusive), and n represents an integer between 0 and 2 (inclusive). However, m + n is equal to 3. X represents a bidentate ligand, and the substructure IrX is one of the structures shown in the following general formulas [3] to [5].

[0010] [ka] In equations [3] through [5], R 41 ~R 55Each is independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heteroaryloxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted silyl group, and a substituted or unsubstituted amino group. Adjacent R 52 to R 55 may be bonded to each other to form a ring. [Effect of the Invention]

[0011] The organic light-emitting device according to the present invention exhibits light emission with good color purity as green, has high luminous efficiency, and excellent driving durability characteristics. In addition, the organic compound according to the present invention exhibits light emission suitable for green light emission and is a compound with high chemical stability. Therefore, by using the organic compound according to the present invention as a constituent material of an organic light-emitting device, an organic light-emitting device having good light-emitting characteristics and excellent durability characteristics can be obtained. [Brief Description of the Drawings]

[0012] [Figure 1] (a) It is a schematic cross-sectional view showing an example of a pixel of a display device according to an embodiment of the present invention. (b) It is a schematic cross-sectional view of an example of a display device using an organic light-emitting device according to an embodiment of the present invention. [Figure 2] It is a schematic diagram showing an example of a display device according to an embodiment of the present invention. [Figure 3] (a) It is a schematic diagram showing an example of an imaging device according to an embodiment of the present invention. (b) It is a schematic diagram showing an example of an electronic device according to an embodiment of the present invention. [Figure 4] (a) It is a schematic diagram showing an example of a display device according to an embodiment of the present invention. (b) It is a schematic diagram showing an example of a foldable display device. [Figure 5] (a) It is a schematic diagram showing an example of a lighting device according to an embodiment of the present invention. (b) It is a schematic diagram showing an example of a moving body having a vehicle lamp according to an embodiment of the present invention. [Figure 6] (a) A schematic diagram showing an example of a wearable device according to one embodiment of the present invention. (b) A schematic diagram showing another example of a wearable device according to one embodiment of the present invention. [Figure 7] (a) A schematic diagram showing an example of an image forming apparatus according to one embodiment of the present invention. (b) A schematic diagram showing an example of an exposure light source for an image forming apparatus according to one embodiment of the present invention. [Modes for carrying out the invention]

[0013] The organic light-emitting element of the present invention comprises a first electrode, a second electrode, and a light-emitting layer disposed between the first and second electrodes. The light-emitting layer comprises a dopant material and a host material, wherein the dopant material is a compound represented by the following general formula [1] or [2], and the host material is a hydrocarbon.

[0014] [ka]

[0015] In formulas [1] to [2], R1 to R 12 , R 21 ~R 32 Each of these is independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heteroaryloxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted silyl group, and a substituted or unsubstituted amino group.

[0016] m represents an integer between 1 and 3 (inclusive), and n represents an integer between 0 and 2 (inclusive). However, m + n is equal to 3.

[0017] X represents a bidentate ligand, and the substructure IrX is one of the structures shown in the following general formulas [3] to [5].

[0018] [ka]

[0019] In equations [3] through [5], R 41 ~R 55 Each is independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heteroaryloxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted silyl group, and a substituted or unsubstituted amino group. 52 ~R 55 These elements may also be joined together to form a ring.

[0020] (1) Characteristics of organic light-emitting diodes The organic light-emitting element of this embodiment is an organic light-emitting element having a first electrode, a second electrode, and a light-emitting layer disposed between the first electrode and the second electrode, and has the following features. (1-1) The light-emitting layer comprises a dopant material and a host material, the dopant material being a compound represented by general formula [1] or [2], and the host material being a hydrocarbon, resulting in strong interaction between the dopant material and the host material and easy energy transfer. (1-2) The effect of (1-1) above promotes hole transport hopping between the dopant material and the host material, thereby improving hole transportability in the light-emitting layer.

[0021] The following describes these features. (1-1) The light-emitting layer comprises a dopant material and a host material, the dopant material being a compound represented by general formula [1] or [2], and the host material being a hydrocarbon, resulting in strong interaction between the dopant material and the host material and easy energy transfer.

[0022] Compounds represented by general formulas [1] or [2] have a phenanthrene ring, which is a fused polycyclic hydrocarbon composed of three benzene rings, as a ligand. On the other hand, a hydrocarbon, preferably a fused polycyclic compound, is used as the host material. Since the dopant material has a fused ring structure with low polarity and aroma as a ligand, a hydrocarbon is selected as the host material, preferably by introducing a fused polycyclic group. This makes it easier for the ligands of the host material and the dopant material (guest material) to undergo ππ interactions, thereby facilitating energy transfer from the host material.

[0023] Here, it is known that the triplet energy used in phosphorescent light-emitting devices is transferred via the Dexter mechanism. In the Dexter mechanism, energy is transferred through contact between molecules. That is, by shortening the intermolecular distance between the host material and the dopant material, energy is efficiently transferred from the host material to the dopant material. Since the dopant material has a fused ring structure with low polarity and aromatic ligands, a hydrocarbon is selected as the host material, preferably a hydrocarbon-based fused ring structure is introduced. This makes it easier for the ligands of the host material and the dopant material to undergo ππ interactions, thereby facilitating energy transfer from the host material.

[0024] Due to the above effects, triplet excitons generated in the host material are quickly consumed for light emission, resulting in a highly efficient organic light-emitting device. Furthermore, material degradation due to high-energy triplet excited states, which occur when triplet excitons not used for light emission are further excited, can be reduced, resulting in good operating durability characteristics for the organic light-emitting device.

[0025] (1-2) The effect of (1-1) above promotes hole transport hopping between the dopant material and the host material, thereby improving hole transportability in the light-emitting layer.

[0026] Compounds represented by general formulas [1] or [2] tend to have a lower HOMO (close to the vacuum level) than the host material due to the effect of having a phenanthrene ring in the ligand. Holes injected from the hole transport layer are transported by the host material, but the holes are repeatedly trapped and detrapped during transport between the dopant material and the host material. In this case, it is preferable that similar skeletons are used for the host material and the dopant material. In this case, the overlap between the condensed rings of the host material and the dopant material is strong, and hole movement between the dopant material and the host material is carried out efficiently. As a result, the voltage rise in the light-emitting layer is suppressed, and an organic light-emitting element with good drive durability characteristics at low voltage is provided.

[0027] Furthermore, it is preferable that the organic light-emitting element of this embodiment has the following features. (1-3) The light-emitting layer further contains an assisting material, the LUMO of the assisting material is smaller than that of the host material (further from the vacuum level). This confines both electron and hole carriers within the light-emitting layer, providing a highly efficient device. (1-4) The effect of (1-3) above reduces the injection of carriers into the adjacent transport layer by passing through the light-emitting layer, thereby reducing the degradation of the transport layer and providing a highly durable element.

[0028] The following describes these features. (1-3) The light-emitting layer further contains an assisting material, the LUMO of the assisting material is smaller than that of the host material (further from the vacuum level). This confines both electron and hole carriers within the light-emitting layer, providing a highly efficient device.

[0029] The iridium complex represented by general formula [1] or [2] promotes the injection of holes into the light-emitting layer. Therefore, it is preferable to improve efficiency by injecting electrons and holes into the light-emitting layer in a balanced manner, and it is preferable to promote the injection of electrons into the light-emitting layer. Since the host material is a hydrocarbon, it has a wide band cap. As a result, the host material has a large LUMO (close to the vacuum level), and it may be difficult to inject electrons from the electron transport layer or hole blocking layer. Therefore, it is preferable to include an assist material in order to facilitate the injection of electrons into the light-emitting layer. Furthermore, it is preferable that the LUMO of the assist material is smaller than that of the host material. This improves the injection of both holes and electrons into the light-emitting layer, maintaining a carrier balance in the light-emitting layer and providing a highly efficient light-emitting element.

[0030] (1-4) The effect of (1-3) above reduces the injection of carriers into the adjacent transport layer by passing through the light-emitting layer, thereby reducing the degradation of the transport layer and providing a highly durable element.

[0031] As described above, the element of this embodiment exhibits the effect of the dopant material in the light-emitting layer promoting hole injection and trapping holes within the light-emitting layer through hole trapping. This reduces the injection of holes from the light-emitting layer into the hole-blocking layer and electron-transporting layer, thereby reducing the degradation of the hole-blocking layer and electron-transporting layer by holes.

[0032] Furthermore, the assist material, which has a smaller LUMO than the host material, promotes electron injection and exhibits the effect of confining electrons in the light-emitting layer through electron trapping. This reduces the injection of electrons from the light-emitting layer to the electron-blocking layer and hole transport layer, thereby reducing the degradation of the electron-blocking layer and hole transport layer by electrons.

[0033] (2) Dopant material (organic compound of the present invention) Dopant materials are compounds represented by the following general formulas [1] or [2]. Note that among the dopant materials, R1 to R 12 At least one of R 21 ~R 32A compound in which at least one is a tertiary alkyl group having 4 or more carbon atoms is an organic compound of the present invention.

[0034]

Chemical formula

[0035] <R1 to R 12 、R 21 to R 32 > In formulas [1] to [2], R1 to R 12 、R 21 to R 32 are each independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heteroaryloxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted silyl group, and a substituted or unsubstituted amino group.

[0036] Examples of the halogen atom include, but are not limited to, fluorine, chlorine, bromine, iodine, etc.

[0037] Examples of the alkyl group include, but are not limited to, methyl group, ethyl group, normal propyl group, isopropyl group, normal butyl group, tertiary butyl group, secondary butyl group, 3-pentyl group, octyl group, cyclohexyl group, tertiary pentyl group, 3-methylpentan-3-yl group, 1-adamantyl group, 2-adamantyl group, etc. The alkyl group is preferably an alkyl group having 1 to 10 carbon atoms.

[0038] Examples of the aralkyl group include, but are not limited to, benzyl group, etc. [[ID= thirty-nine]]

[0039] Examples of alkoxy groups include, but are not limited to, methoxy, ethoxy, propoxy, 2-ethyl-octyloxy, and benzyloxy groups. Preferably, the alkoxy group has 1 to 10 carbon atoms.

[0040] Examples of aryloxy groups include, but are not limited to, phenoxy and naphthoxy groups.

[0041] Examples of heteroaryloxy groups include, but are not limited to, furanyloxy groups and thienyloxy groups.

[0042] Examples of aryl groups include, but are not limited to, phenyl, naphthyl, indenyl, biphenyl, terphenyl, fluorenyl, phenanthryl, triphenylenyl, pyrenyl, anthranyl, perilenyl, chrysenyl, and fluoranthenyl groups. Preferably, the aryl group has 6 to 30 carbon atoms.

[0043] Examples of heterocyclic groups include, but are not limited to, pyridyl, pyrimidyl, pyrazyl, triazyl, thienyl, benzofuranyl, benzothiophenyl, dibenzofuranyl, dibenzothiophenyl, oxazolyl, oxadiazolyl, thiazolyl, thiadiazolyl, carbazolyl, acridinyl, and phenanthrolyl groups. Heterocyclic groups with 3 to 27 carbon atoms are preferred.

[0044] Examples of silyl groups include, but are not limited to, trimethylsilyl and triphenylsilyl groups.

[0045] Examples of amino groups 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-dibenzylamino 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, carbazolyl group, and acridyl group. As the amino group, an amino group having 1 to 32 carbon atoms is preferred.

[0046] Examples of substituents that may further be present include, but are not limited to, alkyl groups, aralkyl groups, alkoxy groups, aryloxy groups, heteroaryloxy groups, aryl groups, heterocyclic groups, silyl groups, and amino groups, as well as alkyl groups such as deuterium, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, and tert-butyl group; aralkyl groups such as benzyl group; aryl groups such as phenyl group and biphenyl group; heterocyclic groups such as pyridyl group and pyrrolyl group; amino groups such as dimethylamino group, diethylamino group, dibenzylamino group, diphenylamino group, and ditolylamino group; alkoxy groups such as methoxy group, ethoxy group, and propoxy group; aryloxy groups such as phenoxy group; halogen atoms such as fluorine, chlorine, bromine, and iodine; cyano groups, and thiol groups.

[0047] R1 to R 12 At least one of R 21 ~R 32 At least one of them is preferably a tertiary alkyl group having 4 or more carbon atoms. Also, R9 to R 12 At least one of R 29 ~R 32It is more preferable that at least one of them is a tertiary alkyl group having 4 or more carbon atoms.

[0048] Examples of tertiary alkyl groups having four or more carbon atoms include, but are not limited to, tertiary butyl, tertiary pentyl, 3-methylpentan-3-yl, and 1-adamantyl groups. Among these, the tertiary butyl group is preferred.

[0049] The dopant material is preferably a compound represented by the general formula [1], R 11 It is more preferable that it is a tert-butyl group.

[0050] <m、n> In equations [1] and [2], m is an integer between 1 and 3 (inclusive), and n is an integer between 0 and 2 (inclusive), where m + n is 3.

[0051] <x> X represents a bidentate ligand, and the substructure IrX is one of the structures shown in the following general formulas [3] to [5].

[0052] [ka]

[0053] [R 41 ~R 55 ] In equations [3] through [5], R 41 ~R 55 Each of these is independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heteroaryloxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted silyl group, and a substituted or unsubstituted amino group.

[0054] R 41 ~R 55 Specific examples of halogen atoms, alkyl groups, aralkyl groups, alkoxy groups, aryloxy groups, heteroaryloxy groups, aryl groups, heterocyclic groups, silyl groups, and amino groups represented by R1 to R 12 , R 21 ~R 32 Examples similar to those described above, but not limited to them, are given. As alkyl groups, alkyl groups having 1 to 10 carbon atoms are preferred. As alkoxy groups, alkoxy groups having 1 to 10 carbon atoms are preferred. As aryl groups, aryl groups having 6 to 30 carbon atoms are preferred. As heterocyclic groups, heterocyclic groups having 3 to 27 carbon atoms are preferred. As amino groups, amino groups having 1 to 32 carbon atoms are preferred. Furthermore, specific examples of substituents that alkyl groups, aralkyl groups, alkoxy groups, aryloxy groups, heteroaryloxy groups, aryl groups, heterocyclic groups, silyl groups, and amino groups may further have include R1 to R 12 , R 21 ~R 32 Examples similar to those explained earlier, but not limited to them, are listed.

[0055] Also, adjacent R 52 ~R 55 They may be joined to each other to form a ring. 52 ~R 55 The statement that R is a link to another is that R 52 and R 53 , R 53 and R 54 , R 54 and R 55 A ring formed by the bonding of R 52 ~R 55 This means that the benzene ring to which the R is bonded forms a fused ring. 52 ~R 55 The ring formed by the bonding of these elements may be an aromatic ring.

[0056] Compounds represented by general formulas [1] or [2] have the following characteristics: (2-1) The ligand has a phenanthrene ring, which gives it an emission wavelength of 520 nm to 540 nm, preferably 520 nm to 535 nm, which is required for a green light-emitting dopant. (2-2) The ligand has a phenanthrene ring, which gives it high hole transport capability. The following describes these features.

[0057] (2-1) The ligand has a phenanthrene ring, which gives it an emission wavelength of 520 nm to 540 nm, preferably 520 nm to 535 nm, which is required for a green light-emitting dopant.

[0058] The iridium complex represented by general formula [1] or [2] exhibits high oscillator strength and high quantum yield due to the coordination of a phenanthrene ring, which consists of three benzene rings fused to iridium. Furthermore, as shown in Table 1, compounds 1 and 2, which have a phenanthrene ring as a ligand, exhibit longer emission wavelengths compared to comparative compound 1, having emission wavelengths of 520 nm to 540 nm, preferably 520 nm to 535 nm, which are necessary for green emission dopants. Compound 1 is the exemplary compound B-1 described later, and compound 2 is the exemplary compound H-1 described later. The emission wavelength used was the peak value of the emission spectrum in a dilute toluene solution.

[0059] [Table 1]

[0060] (2-2) The ligand has a phenanthrene ring, which gives it high hole transport capability.

[0061] Iridium complexes represented by general formulas [1] or [2] exhibit high hole transport properties due to the presence of phenanthrene rings in their ligands. This is thought to be due to the structure, which allows the phenanthrene rings of the ligands to easily overlap, facilitating hole hopping between ligands.

[0062] Furthermore, compounds represented by general formula [1] or [2] are preferably characterized by the following: (2-3)R1 to R 12 At least one of R 21 ~R 32 The sublimation properties are improved if at least one of the components is a tertiary alkyl group having 4 or more carbon atoms. (2-4)R9 to R 12 At least one of R 29 ~R 32 It is even more preferable that at least one of them is a tertiary alkyl group having 4 or more carbon atoms. (2-5) The compound represented by general formula [1] has an emission wavelength that is even more optimal as a green emission dopant compared to the compound represented by general formula [2]. The following describes these features.

[0063] (2-3)R1 to R 12 At least one of R 21 ~R 32 The sublimation properties are improved if at least one of the components is a tertiary alkyl group having 4 or more carbon atoms.

[0064] Iridium complexes represented by general formulas [1] or [2] have the characteristics described above (2-1) and (2-2) due to the presence of a phenanthrene ring in the ligand, but the presence of condensed polycyclic rings results in a large molecular weight for the complex and poor sublimation properties. Specifically, this can occur when the temperature during sublimation purification is high, or when the complex partially decomposes after sublimation purification. Therefore, R1 to R 12 At least one of R 21 ~R 32 Preferably, at least one of the components is a tertiary alkyl group having 4 or more carbon atoms. This suppresses molecular stacking between the complexes and lowers the sublimation temperature. The alkyl group having 4 or more carbon atoms has a strong exclusion effect between the complexes and a strong effect in suppressing molecular stacking. The tertiary alkyl group reduces the radical cleavage of the benzyl hydrogen atom at high temperatures.

[0065] Table 2 shows the bond dissociation energies of carbon-hydrogen bonds as described in ACC.Chem.Res.36,255-263,(2003).

[0066] [Table 2]

[0067] A higher bond dissociation energy indicates a stronger bond, while a lower energy indicates a weaker bond. Therefore, the carbon-hydrogen bond at the benzyl position is a weak bond. This is because when the hydrogen atom at the benzyl position is eliminated and forms a radical, the radical is stabilized by resonance of π electrons with the adjacent benzene ring. For this reason, the carbon-hydrogen bond at the benzyl position is weak. In other words, compounds without structures like the benzyl group in their molecular structure are preferable because the carbon-hydrogen bond is less likely to be broken.

[0068] Table 3 shows the sublimation temperatures during the sublimation purification of each material. The vacuum level during sublimation purification is 1 × 10⁻⁶. -3 From 1 x 10 -2 Pa. Compound 5 is example compound A-1, which will be described later. From Table 3, R1 to R 12 At least one of R 21 ~R 32 It can be seen that the sublimation temperature is lower when at least one of the elements is a tertiary alkyl group having 4 or more carbon atoms.

[0069] [Table 3]

[0070] (2-4)R9 to R 12 At least one of R 29 ~R 32 It is even more preferable that at least one of them is a tertiary alkyl group having 4 or more carbon atoms.

[0071] The tertiary alkyl groups with four or more carbon atoms described in (2-3) are substituents with high electron-donating properties. In iridium complexes represented by general formulas [1] or [2], the LUMO is distributed on the pyridine ring side bonded to the phenanthrene ring of the ligand. Therefore, R9 to R 12 At least one of R 29 ~R 32 At least one of the atoms is a tertiary alkyl group having 4 or more carbon atoms, which shortens the emission wavelength, resulting in an emission wavelength with better color purity and a greener appearance. Table 4 shows the R in general formula [1] 11 This shows the difference in emission wavelength depending on whether or not it is a tert-butyl group. 11 The presence of a tert-butyl group shortens the emission wavelength by about 5 nm, resulting in an emission wavelength with better color purity and a more pronounced green color.

[0072] [Table 4]

[0073] Furthermore, as described in (2-2), iridium complexes represented by general formulas [1] or [2] exhibit high hole transport properties due to the presence of phenanthrene rings in their ligands. This is thought to be due to the structure in which the phenanthrene rings of the ligands easily overlap, facilitating hole hopping between ligands. Therefore, to avoid reducing the overlap between phenanthrene rings, R9 to R 12 At least one of R 29 ~R 32 It is even more preferable that at least one of them is a tertiary alkyl group having 4 or more carbon atoms.

[0074] (2-5) The compound represented by general formula [1] has an emission wavelength that is even more optimal as a green emission dopant compared to the compound represented by general formula [2].

[0075] Comparing compound 1 and compound 2 in Table 1, compound 1 exhibits shorter wavelength emission, resulting in a more green color purity. The compound represented by general formula [1] is thought to have lower electron-donating ability of the phenanthrene ring, thus resulting in a shorter emission wavelength.

[0076] <Specific example> Specific examples of compounds represented by general formula [1] or [2] that are dopant materials according to the present invention are shown below. (Compounds belonging to groups A, C, E, G, I, and K are examples.) However, the present invention is not limited to these.

[0077] [ka]

[0078] [ka]

[0079] [ka]

[0080] [ka]

[0081] [ka]

[0082] [ka]

[0083] [ka]

[0084] [ka]

[0085] [ka]

[0086] [ka]

[0087] The exemplary compounds belonging to group A are compounds represented by the general formula [1] that have two ligands containing phenanthrene rings. Having two highly planar phenanthrene rings results in high hole mobility and a high degree of orientation of the compound, which improves the light extraction from the light-emitting element.

[0088] Examples of compounds belonging to group B are compounds represented by the general formula [1] that have two ligands containing a phenanthrene ring, and the ligands containing the phenanthrene ring have a tertiary alkyl group having 4 or more carbon atoms. By reducing intermolecular stacking, sublimation is improved and concentration quenching in the luminescent layer can be reduced.

[0089] Examples of compounds belonging to group C are compounds represented by the general formula [1] that have one ligand containing a phenanthrene ring. Due to the presence of a highly planar phenanthrene ring, they have high hole mobility. In addition, they have lower molecular weights and lower sublimation temperatures compared to compounds belonging to group A.

[0090] Examples of compounds belonging to group D are compounds represented by the general formula [1] that have one ligand containing a phenanthrene ring, and the ligand containing the phenanthrene ring has a tertiary alkyl group having 4 or more carbon atoms. By reducing intermolecular stacking compared to compounds of group C, sublimation properties are improved and concentration quenching in the luminescent layer can be reduced.

[0091] Examples of compounds belonging to group E are compounds represented by the general formula [1] that have three ligands containing phenanthrene rings. Having three highly planar phenanthrene rings results in extremely high hole mobility.

[0092] Examples of compounds belonging to group F are compounds represented by the general formula [1] that have three ligands containing a phenanthrene ring, and each ligand containing a phenanthrene ring has a tertiary alkyl group with 4 or more carbon atoms. By reducing intermolecular stacking compared to compounds of group E, sublimation is improved and concentration quenching in the luminescent layer can be reduced.

[0093] Examples of compounds belonging to group G are compounds that have two ligands containing phenanthrene rings in the compound represented by general formula [2]. Having two highly planar phenanthrene rings results in high hole mobility and a high degree of orientation of the compound, which improves the light extraction from the light-emitting element.

[0094] Examples of compounds belonging to group H are compounds represented by the general formula [2] that have two ligands containing a phenanthrene ring, and the ligands containing the phenanthrene ring have a tertiary alkyl group having 4 or more carbon atoms. By reducing intermolecular stacking, sublimation is improved and concentration quenching in the luminescent layer can be reduced.

[0095] Examples of compounds belonging to Group I are compounds represented by the general formula [2] that have one ligand containing a phenanthrene ring. They have high hole mobility due to the presence of a highly planar phenanthrene ring. Furthermore, they have lower molecular weights and lower sublimation temperatures compared to compounds belonging to Group G.

[0096] The exemplary compounds belonging to group J are compounds represented by the general formula [2] that have one ligand containing a phenanthrene ring, and the ligand containing the phenanthrene ring has a tertiary alkyl group having 4 or more carbon atoms. By reducing intermolecular stacking compared to the compounds of group I, sublimation properties are improved and concentration quenching in the luminescent layer can be reduced.

[0097] Examples of compounds belonging to group K are compounds represented by the general formula [2] that have three ligands containing phenanthrene rings. Having three highly planar phenanthrene rings results in extremely high hole mobility.

[0098] Exemplary compounds belonging to group L are compounds represented by the general formula [2] that have three ligands containing a phenanthrene ring, and each ligand containing a phenanthrene ring has a tertiary alkyl group with 4 or more carbon atoms. By reducing intermolecular stacking compared to compounds of group K, sublimation is improved and concentration quenching in the luminescent layer can be reduced.

[0099] Among these, the following compounds are preferred.

[0100] [ka]

[0101] (3) Host material The host material is a hydrocarbon. Preferably, the host material has a T1 (lowest triplet excitation energy) higher than the dopant material, which is an iridium complex represented by general formula [1] or [2]. Specifically, since the dopant material of this embodiment has an emission region of 520 nm to 540 nm, preferably 520 nm to 535 nm, the T1 of the host material is preferably 2.4 eV or higher. Furthermore, as described above, to enhance the interaction between the ligand of the dopant material and the phenanthrene ring, a polycyclic compound with three or more rings is preferred.

[0102] Furthermore, the host material preferably has the following characteristics: (3-1) It has at least one of the following rings in its skeleton: a triphenylene ring, a chrysene ring, or a fluorantene ring. (3-2)SP 3 It does not contain carbon.

[0103] The following describes these features. (3-1) It has at least one of the following rings in its skeleton: a triphenylene ring, a chrysene ring, or a fluorantene ring.

[0104] The dopant material of this embodiment has a phenanthrene skeleton in the ligand. The phenanthrene skeleton has a highly planar structure. Since the dopant material and the host material interact as described in (1-1) and (1-2) above, it is preferable that the host material also has a highly planar structure. This is because having a highly planar structure allows highly planar sites to approach each other through interaction. More specifically, the phenanthrene site of the dopant material and the planar site of the host material are more likely to approach each other. Therefore, it can be expected that the intermolecular distance between the dopant material and the host material will be shortened. The above effects lead to the effect of increasing the efficiency of energy transfer described in (1-1).

[0105] Here, a highly planar structure refers to, for example, a structure of a hydrocarbon containing a condensed polycycle such as a triphenylene ring, a chrysene ring, a fluoranthene ring, or a phenanthrene ring. Among these, the triphenylene ring, the chrysene ring, and the fluoranthene ring have a different structure from the phenanthrene ring of the ligand of the dopant material, and the interaction with the dopant material is appropriate. Therefore, the emission wavelength of the dopant material is shortened, which is preferable.

[0106] (3-2) The host material is SP 3 Does not have carbon.

[0107] As described in the above explanation (3-1), the dopant material of this embodiment is a compound having the characteristic that its interaction and emission characteristics are improved by improving the distance from the host material. As the host material, further SP 3 By becoming a compound that does not have carbon, the distance from the dopant material can be shortened.

[0108] <Specific examples> Specific examples of the host material are shown below, but of course, they are not limited to these.

[0109]

Chemical formula

[0110] [ka]

[0111] The above example compounds have at least one of the following rings in their skeleton: a triphenylene ring, a phenanthrene ring, a chrysene ring, or a fluorantene ring, and SP 3 These are carbon-free compounds. As a result, these compounds can get closer to the dopant material of this embodiment, resulting in strong interactions and serving as host materials that facilitate good energy transfer to the dopant material. Among these, compounds having a triphenylene ring, a chrysene ring, or a fluorantene ring in their skeleton are preferred, and compounds having a triphenylene ring in their skeleton are particularly preferred due to their high planarity.

[0112] (4) Assist materials The light-emitting layer preferably further contains an assisting material. The LUMO of the assisting material is preferably smaller than that of the host material (further from the vacuum level). The assisting material is more preferably a compound having one of the following structures in part.

[0113] [ka] (In the above structure, X represents an oxygen atom, a sulfur atom, or a substituted or unsubstituted carbon atom.)

[0114] The above structure is effective because it has electron-withdrawing properties and can reduce the LUMO of the assist material. Furthermore, as a substructure, an assist material containing the above structure is preferable because it has moderately high electron-withdrawing properties and a moderately sized structure, making it less likely to form an exciplex with the dopant material of this embodiment. An example of an assist material that is considered likely to form an exciplex with the dopant material of this embodiment is a compound containing a triazine ring as a substructure.

[0115] The above structure may be unsubstituted or substituted. Furthermore, the carbon atom represented by X may be unsubstituted or substituted. Examples of substituents include halogen atoms, alkyl groups, alkoxy groups, aryloxy groups, heteroaryloxy groups, aryl groups, heterocyclic groups, silyl groups, and amino groups.

[0116] Examples of halogen atoms include, but are not limited to, fluorine, chlorine, bromine, and iodine.

[0117] Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, secondary butyl, octyl, cyclohexyl, 1-adamantyl, and 2-adamantyl groups.

[0118] Examples of alkoxy groups include, but are not limited to, methoxy, ethoxy, propoxy, 2-ethyl-octyloxy, and benzyloxy groups.

[0119] Examples of aryloxy groups include, but are not limited to, phenoxy and naphthoxy groups.

[0120] Examples of heteroaryloxy groups include, but are not limited to, furanyloxy groups and thienyloxy groups.

[0121] Examples of aryl groups include, but are not limited to, phenyl, naphthyl, indenyl, biphenyl, terphenyl, fluorenyl, phenanthryl, triphenylenyl, pyrenyl, anthranyl, perilenyl, chrysenyl, and fluoranthenyl groups.

[0122] Examples of heterocyclic groups include, but are not limited to, pyridyl, pyrimidyl, pyrazyl, triazyl, benzofuranyl, benzothiophenyl, dibenzofuranyl, dibenzothiophenyl, oxazolyl, oxadiazolyl, thiazolyl, thiadiazolyl, carbazolyl, acridinyl, and phenanthrolyl groups.

[0123] Examples of silyl groups include, but are not limited to, trimethylsilyl and triphenylsilyl groups.

[0124] Examples of amino groups 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-dibenzylamino 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, carbazolyl group, and acridyl group.

[0125] The alkyl, alkoxy, amino, aryl, heterocyclic, aryloxy, and silyl groups may have further substituents, and examples of substituents include, but are not limited to, deuterium, alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, and tert-butyl groups, aralkyl groups such as benzyl groups, aryl groups such as phenyl and biphenyl groups, heterocyclic groups such as pyridyl and pyrrolyl groups, amino groups such as dimethylamino, diethylamino, dibenzylamino, diphenylamino, and ditolylamino groups, alkoxy groups such as methoxy, ethoxy, and propoxy groups, aryloxy groups such as phenoxy groups, halogen atoms such as fluorine, chlorine, bromine, and iodine, and cyano groups.

[0126] <Specific example> Specific examples of assisting materials are shown below, but of course, these are not the only examples.

[0127] [ka]

[0128] [ka]

[0129] [ka]

[0130] (5) Details of organic light-emitting devices Next, the organic light-emitting element of this embodiment will be described in detail.

[0131] The organic light-emitting element of this embodiment comprises at least a first electrode, a second electrode, and an organic compound layer disposed between the first electrode and the second electrode. 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, provided that 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, and the like. The light-emitting layer may also be a single layer or a laminate consisting of multiple layers.

[0132] In the organic light-emitting element of this embodiment, at least one layer of the organic compound layer contains the organic compound according to this embodiment. Specifically, the organic compound according to this embodiment is included in any of the above-mentioned light-emitting layer, hole injection layer, hole transport layer, electron blocking layer, light-emitting layer, hole-exciton blocking layer, electron transport layer, electron injection layer, etc. The organic compound according to this embodiment is preferably included in the light-emitting layer.

[0133] In the organic light-emitting element of this embodiment, if 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 organic compound according to this embodiment and other compounds. Here, if the light-emitting layer consists of the organic compound according to this embodiment and other compounds, the organic compound according to this embodiment may be used as a host for the light-emitting layer, or as a guest (dopant). It may also be used as an assist material that can be included in the light-emitting layer.

[0134] Here, the host is the compound with the largest mass ratio among the compounds that make up the luminescent layer. The guest is the compound that has a smaller mass ratio than the host among the compounds that make up the luminescent layer and is responsible for the primary luminescence. The assist material is the compound that has a smaller mass ratio than the host among the compounds that make up the luminescent layer and assists the luminescence of the guest.

[0135] Here, 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 5% by mass or less, relative to the entire light-emitting layer.

[0136] When the organic compound according to this embodiment is used as an assist material for the light-emitting layer, the concentration of the assist material is preferably 0.1% by mass or more and 45% by mass or less, and more preferably 1% by mass or more and 30% by mass or less, relative to the entire light-emitting layer.

[0137] The inventors have conducted various studies and found that when the organic compound according to this embodiment is used as a host, guest, or assist material for the light-emitting layer, particularly as a guest material for the light-emitting layer, a device exhibiting high efficiency, high brightness, and extremely high durability can be obtained. Furthermore, they found that when used as an assist material for the light-emitting layer, a device exhibiting high efficiency, high brightness, and extremely high durability can be obtained. This light-emitting layer may be a single layer or a multi-layer, and may also contain multiple light-emitting materials. A multi-layer can be a state in which one light-emitting layer is stacked with another light-emitting layer, or an intermediate layer may be stacked between multiple light-emitting layers. It may also be a tandem element or a stacked element. In these cases, the light-emitting color of the organic light-emitting element is not limited to a single color. More specifically, it may be white or an intermediate color.

[0138] Furthermore, the film is formed by either vapor deposition or coating. Details of this will be explained in the examples described later.

[0139] The organic compound 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 element 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.

[0140] 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.

[0141] 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 reduce film quality degradation such as crystallization in organic light-emitting devices. 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.

[0142] [ka]

[0143] 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.

[0144] In addition to the luminescent dopant of this embodiment, other luminescent dopants may be used. Examples 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. Specific examples of compounds used as luminescent materials are shown below, but are of course not limited to these.

[0145] [ka]

[0146] [ka]

[0147] When the luminescent material is a hydrocarbon compound, it is preferable because it reduces the decrease in luminescence efficiency due to excyplex formation and the deterioration of color purity due to changes in the emission spectrum of the luminescent material. Hydrocarbon compounds are compounds composed only of carbon and hydrogen, and include BD7, BD8, GD5 to GD9, and RD1.

[0148] When the light-emitting material is a condensed polycyclic material containing a five-membered ring, it is even more preferable because its ionization potential is high, making it less susceptible to oxidation and providing a device with a long and durable lifespan. BD7, BD8, GD5 to GD9, and RD1 are examples of this.

[0149] Other host materials or assist materials may be used besides those specified in this embodiment. For example, in addition to aromatic hydrocarbon compounds or their derivatives, examples include carbazole derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, organoaluminum complexes such as tris(8-quinolinolate)aluminum, and organoberylium complexes.

[0150] The following are some specific examples of compounds, but of course, they are not the only ones.

[0151] [ka]

[0152] When the host material is a hydrocarbon compound, the compound of this embodiment is preferable because it can easily trap electrons and holes, resulting in a significant improvement in efficiency. A hydrocarbon compound is a compound composed only of carbon and hydrogen, and corresponds to EM1 to EM12 and EM16 to EM27.

[0153] 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. Specific examples of compounds used as electron-transporting materials are shown below, but are of course not limited to these.

[0154] [ka]

[0155] 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.

[0156] <Configuration of an 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 second electrode. 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.

[0157] [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.

[0158] [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.

[0159] 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.

[0160] 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.

[0161] 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.

[0162] 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.

[0163] 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.

[0164] [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.

[0165] 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.

[0166] 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.).

[0167] 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.

[0168] 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.

[0169] 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.

[0170] [Protective layer] A protective layer may be provided on the second electrode. For example, by bonding glass with a desiccant to the second electrode, 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 second electrode to reduce the intrusion of water and other substances into the organic compound layer. For example, after forming the second electrode, 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 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.

[0171] [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.

[0172] [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.

[0173] 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.

[0174] [Microlens] An organic light-emitting element or 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 element or 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.

[0175] 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.

[0176] [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.

[0177] [Pixel circuit] An organic light-emitting device having an organic light-emitting element may have a pixel circuit connected to the organic 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 driving circuit has a pixel circuit for each pixel. The pixel circuit may include 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.

[0178] 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. The slope of the current-voltage characteristic of the transistors constituting the pixel circuit may be smaller than the slope of the current-voltage characteristic of the transistors constituting the display control circuit. The slope of the current-voltage characteristic can be measured by the so-called Vg-Ig characteristic. The transistors constituting the pixel circuit are transistors connected to the light-emitting element, such as the first light-emitting element.

[0179] [Pixels] An organic light-emitting device having an organic light-emitting element may have a plurality of pixels. Each pixel may have subpixels that emit light of a different color from the others. The subpixels may each have, for example, RGB light-emitting colors.

[0180] A pixel emits light from 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. The distance between subpixels may be 10 μm or less, and specifically, it may be 8 μm, 7.4 μm, 6.4 μm.

[0181] 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.

[0182] <Applications of the organic light-emitting element according to this embodiment> The organic light-emitting element according to this embodiment 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.

[0183] The display device may also be an image information processing device having an image input unit that receives image information from an area CCD, linear CCD, memory card, etc., an information processing unit that processes the input information, and displays the input image on a display unit. The display device may have a plurality of pixels, and at least one of the plurality of pixels may have the organic light-emitting element of this embodiment and a transistor connected to the organic light-emitting element.

[0184] 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.

[0185] Next, a display device according to this embodiment will be described with reference to the drawings. Figure 1 is a schematic cross-sectional view showing an example of a display device having an organic light-emitting element and a transistor connected to the organic light-emitting element. The transistor is an example of an active element. The transistor may be a thin-film transistor (TFT).

[0186] Figure 1(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 10 has a reflective electrode which is a first electrode 2 on an interlayer insulating layer 1, an insulating layer 3 covering the end of the first electrode 2, an organic compound layer 4 covering the first electrode 2 and the insulating layer 3, a transparent electrode which is a second electrode 5, a protective layer 6, and a color filter 7.

[0187] 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 2 may be electrically connected via a contact hole or the like (not shown).

[0188] The insulating layer 3 is also called a bank or pixel isolation layer. It covers the edge of the first electrode 2 and surrounds the first electrode 2. The portion not covered by the insulating layer 3 is in contact with the organic compound layer 4 and becomes the light-emitting region.

[0189] 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.

[0190] The second electrode 5 may be a transparent electrode, a reflective electrode, or a semi-transparent electrode.

[0191] The protective layer 6 reduces the penetration of moisture into the organic compound layer 4. Although the protective layer 6 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.

[0192] The color filter 7 is classified into 7R, 7G, and 7B according to its color. The color filter 7 may be formed on a planarization film (not shown). The color filter 7 may also have a resin protective layer (not shown). Alternatively, the color filter 7 may be formed on a protective layer 6. Or it may be bonded to an opposing substrate such as a glass substrate after being placed on it.

[0193] The display device 100 in Fig. 1(b) has an organic light-emitting element 26 and a TFT 18 as an example of a transistor. A substrate 11 such as glass or silicon and an insulating layer 12 are provided on the upper part thereof. Active elements such as the TFT 18 are arranged on the insulating layer 12, and a gate electrode 13, a gate insulating film 14, and a semiconductor layer 15 of the active element are arranged. The TFT 18 is also composed of a drain electrode 16 and a source electrode 17. An insulating film 19 is provided on the upper part of the TFT 18. The anode 21 constituting the organic light-emitting element 26 and the source electrode 17 are connected through a contact hole 20 provided in the insulating film 19.

[0194] Note that the electrical connection method between the electrodes (anode 21, cathode 23) included in the organic light-emitting element 26 and the electrodes (source electrode 17, drain electrode 16) included in the TFT 18 is not limited to the mode shown in Fig. 1(b). That is, it is sufficient that either one of the anode 21 or the cathode 23 and either one of the source electrode 17 or the drain electrode 16 of the TFT 18 are electrically connected. The TFT refers to a thin-film transistor.

[0195] In the display device 100 of Fig. 1(b), the organic compound layer 22 is shown as if it were a single layer, but the organic compound layer 22 may be a plurality of layers. A first protective layer 24 and a second protective layer 25 for reducing the deterioration of the organic light-emitting element 26 are provided on the cathode 23.

[0196] In the display device 100 of Fig. 1(b), a transistor is used as a switching element, but other switching elements may be used instead.

[0197] Also, the transistor used in the display device 100 of FIG. 1(b) is not limited to a transistor using a single-crystalline silicon wafer, and may be a thin-film transistor having an active layer on an insulating surface of a substrate. Examples of the active layer include non-single-crystalline silicon such as single-crystalline silicon, amorphous silicon, and microcrystalline silicon, and non-single-crystalline oxide semiconductors such as indium zinc oxide and indium gallium zinc oxide. Note that a thin-film transistor is also called a TFT element.

[0198] The transistor included in the display device 100 of FIG. 1(b) may be formed in a substrate such as a Si substrate. Here, forming in the substrate means manufacturing a transistor by processing the substrate itself such as a Si substrate. That is, having a transistor in the substrate can also be regarded as the substrate and the transistor being integrally formed.

[0199] The organic light-emitting element according to the present embodiment has its emission luminance controlled by a TFT, which is an example of a switching element, and an image can be displayed according to the emission luminance of each organic light-emitting element provided on a plurality of planes. Note that the switching element according to the present embodiment is not limited to a TFT, and may be a transistor formed of low-temperature polysilicon or an active matrix driver formed on a substrate such as a Si substrate. "On the substrate" can also mean "in the substrate". Whether to provide a transistor in the substrate or use a TFT is selected according to the size of the display portion. For example, if the size is about 0.5 inches, it is preferable to provide an organic light-emitting element on a Si substrate.

[0200] Figure 2 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.

[0201] 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.

[0202] 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.

[0203] 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.

[0204] Figure 3(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.

[0205] 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 this embodiment, 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.

[0206] 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.

[0207] Figure 3(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 1202 may also be a biometric recognition unit that recognizes a fingerprint to unlock the device, etc. An electronic device having a communication unit can also be called a communication device. The electronic device 1200 may further have a camera function by including a lens and an image sensor. The image captured by the camera function is displayed on the display unit 1201. Examples of electronic devices 1200 include smartphones and laptop computers.

[0208] Figure 4 is a schematic diagram showing an example of a display device according to this embodiment. Figure 4(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 a light-emitting element according to this embodiment. 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 4(a). The lower edge of the frame 1301 may also serve as the base. In addition, the frame 1301 and the display unit 1302 may be curved. The radius of curvature may be 5000 mm or more and 6000 mm or less.

[0209] Figure 4(b) is a schematic diagram showing another example of the display device according to this embodiment. The display device 1310 in Figure 4(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 elements 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 by 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.

[0210] Figure 5(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, and an optical filter 1404 and a light diffusion unit 1405 that transmit light emitted from the light source 1402. The light source 1402 may have an organic light-emitting element according to this embodiment. The optical filter 1404 may be a filter that improves the color rendering of the light source. The light diffusion unit 1405 can effectively diffuse the light from the light source, such as for lighting up, and deliver light over a wide area. The optical filter 1404 and the light diffusion unit 1405 may be provided on the light-emitting side of the lighting. A cover may be provided on the outermost part as needed.

[0211] 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 this embodiment 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.

[0212] 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.

[0213] Figure 5(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.

[0214] The tail lamp 1501 may include the organic light-emitting device according to this embodiment. The tail lamp 1501 may include a protective member that protects the organic light-emitting device. The protective member has a certain degree of strength and may be made of any material as long as it is transparent, but it is preferably made of polycarbonate or the like. A phthalic acid derivative, an acrylonitrile derivative, or the like may be mixed with the polycarbonate.

[0215] The vehicle 1500 may include a vehicle body 1503 and a window 1502 attached thereto. The window 1502 may be a transparent display as long as it is not a window for checking the front and rear of the vehicle. The transparent display may include the organic light-emitting device according to this embodiment. In this case, constituent materials such as electrodes of the organic light-emitting device are made of transparent members.

[0216] The moving body according to this embodiment may be a ship, an aircraft, a drone, or the like. The moving body may include a fuselage and a lamp provided on the fuselage. The lamp may emit light to indicate the position of the fuselage. The lamp includes the organic light-emitting device according to this embodiment.

[0217] Referring to FIG. 6, application examples of the display device according to each of the above embodiments will be described. The display device can be applied to a system that can be worn as a wearable device such as, for example, smart glasses, an HMD, or smart contacts. The imaging display device used in such an application example includes an imaging device capable of photoelectrically converting visible light and a display device capable of emitting visible light.

[0218] FIG. 6(a) is a schematic diagram showing an example of a wearable device according to an embodiment of the present invention. Using FIG. 6(a), glasses 1600 (smart glasses) according to one application example will be described. An imaging device 1602 such as a CMOS sensor or a SPAD is provided on the front surface side of the lens 1601 of the glasses 1600. Further, on the back surface side of the lens 1601, the display device according to each of the above embodiments is provided.

[0219] 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. 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.

[0220] Figure 6(b) is a schematic diagram showing another example of a wearable device according to one embodiment of the present invention. Using Figure 6(b), we will describe a pair of glasses 1610 (smart glasses) according to one application example. The glasses 1610 have a control device 1612, which is equipped with an imaging device corresponding to the imaging device 1602 in Figure 6(a) 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 in the control device 1612, and an image is projected onto the lens 1611. The control device 1612 functions as a power supply that supplies power to the imaging device and the display device, and also controls the operation of the imaging device and the display device.

[0221] The control device 1612 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 user's eyeball that is fixated on the displayed image. An imaging unit having 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 a planar view, the degradation of image quality is reduced. The user's gaze toward the displayed image is detected from the image of the eyeball obtained by imaging with infrared light. Any known method can be applied to gaze detection using the image of the eyeball. As an example, a gaze detection method based on the Purkinje image obtained by the reflection of irradiated light from the cornea can be used. More specifically, gaze detection processing based on the pupil-corneal reflection method is performed. Using the pupil-corneal reflection method, the user's gaze is detected by calculating a gaze vector representing the orientation (rotation angle) of the eyeball based on the pupil image and Purkinje image included in the image of the eyeball.

[0222] A display device according to one embodiment of the present invention has 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. Specifically, the display device determines a first field of view area that the user is fixated on and a second field of view area other than the first field of view area, based on the gaze information. The first field of view area and the second field of view area 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. In the display area of ​​the display device, the display resolution of the first field of view area may be controlled to be higher than the display resolution of the second field of view area. In other words, the resolution of the second field of view area may be lower than that of the first field of view area.

[0223] 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 set lower.

[0224] 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.

[0225] When display control is based on visual detection, this method is preferably applicable to smart glasses that further include an imaging device for capturing images of the surrounding environment. The smart glasses can display the captured external information in real time.

[0226] Figure 7(a) is a schematic diagram showing an example of an image forming apparatus according to one embodiment of the present invention. The image forming apparatus 40 is an electrophotographic image forming apparatus and includes a photoreceptor 27, an exposure light source 28, a charging unit 30, a developing unit 31, a transfer unit 32, a transport roller 33, and a fuser 35. Light 29 is irradiated from the exposure light source 28, and an electrostatic latent image is formed on the surface of the photoreceptor 27. This exposure light source 28 has an organic light-emitting element according to this embodiment. The developing unit 31 contains toner or the like. The charging unit 30 charges the photoreceptor 27. The transfer unit 32 transfers the developed image to a recording medium 34. The transport roller 33 transports the recording medium 34. The recording medium 34 is, for example, paper. The fuser 35 fixes the image formed on the recording medium 34.

[0227] Figures 7(b) and 7(c) are diagrams showing the exposure light source 28, schematic diagrams showing how multiple light-emitting units 36 are arranged on a long substrate. The arrow 37 is parallel to the axis of the photoreceptor and represents the column direction in which the organic light-emitting elements are arranged. This column direction is the same as the direction of the axis in which the photoreceptor 27 rotates. This direction can also be called the long axis direction of the photoreceptor 27. Figure 7(b) shows a configuration in which the light-emitting units 36 are arranged along the long axis direction of the photoreceptor 27. Figure 7(c) is a different configuration from Figure 7(b), in which the light-emitting units 36 are arranged alternately in the column direction in the first column and the second column. The first column and the second column are arranged at different positions in the row direction. In the first column, multiple light-emitting units 36 are arranged with intervals between them. In the second column, light-emitting units 36 are located at positions corresponding to the intervals between the light-emitting units 36 in the first column. That is, multiple light-emitting units 36 are also arranged with intervals between them in the row direction. The arrangement in Figure 7(c) can also be described as a grid pattern, a houndstooth pattern, or a checkerboard pattern.

[0228] As described above, by using the device employing the organic light-emitting element according to this embodiment, it becomes possible to display images with good quality and stable display even for extended periods. [Examples]

[0229] The present invention will be described below with reference to examples. However, the present invention is not limited to these examples.

[0230] [Example 1 (Synthesis of Exemplary Compound C-1)] (Reference example) Exemplary compound C-1 was synthesized according to the following scheme. [ka]

[0231] (1) Synthesis of compound f-3 The following reagents and solvents were placed in a 200 ml round-bottom flask. Compound f-1: 6.08g (20.0mmol) Compound f-2: 2.27g (20.0mmol) Sodium carbonate: 5.3g (50.0 mmol) Pd(PPh3)4: 578mg Toluene: 35ml Water: 35ml Ethanol: 10ml Next, the reaction solution was heated and stirred at 60°C under a nitrogen stream for 5 hours. After the reaction was complete, the organic layer was extracted with toluene and concentrated to dryness. The resulting solid was purified by silica gel column chromatography (toluene:ethyl acetate mixture) to obtain 3.0 g of clear solid (f-3) (yield: 58%).

[0232] (2) Synthesis of compound f-5 The following reagents and solvents were placed in a 50 ml round-bottom flask. Compound f-4: 3.10g (20.0mmol) Iridium chloride hydrate: 1.60g Ethoxyethanol: 18ml Water: 6ml Next, the reaction solution was heated and stirred at 130°C under a nitrogen stream for 5 hours. After the reaction was complete, the reaction solution was filtered, and the resulting solid was washed with water and methanol on the filter. 3.4 g of yellow solid (f-5) was obtained (yield: 63%).

[0233] (3) Synthesis of compound f-6 The following reagents and solvents were placed in a 100 ml round-bottom flask. Compound f-5: 1.07g (1.00mmol) Silver triflate: 0.514g (2.00 mmol) Methylene chloride: 30 ml Methanol: 1.3 ml Next, the reaction solution was heated and stirred at room temperature under a nitrogen stream for 7 hours. After the reaction was complete, the solvent was removed from the reaction solution at 40°C. 1.56 g of a yellowish-brown solid (f-6) was obtained.

[0234] (4) Synthesis of Exemplary Compound C-1 The following reagents and solvents were placed in a 100 ml round-bottom flask. Compound f-6: 1.50g Compound f-3: 2.55g (1.00mmol) Ethanol: 50ml Next, the reaction solution was heated and stirred at 90°C under a nitrogen stream for 5 hours. After the reaction was complete, the reaction solution was filtered, and the resulting solid was washed with water and methanol on the filter. The resulting solid was purified by silica gel column chromatography (toluene:ethyl acetate mixture) to obtain 0.17 g of a yellow solid (exemplary compound C-1) (yield: 23%).

[0235] For example compound C-1, mass spectrometry was performed using MALDI-TOF-MS (Bruker Autoflex LRF). [MALDI-TOF-MS] Measured value: m / z = 755 Calculated value: C 41 H 28 IrN3=755

[0236] [Example 2] ~ 24 (Synthesis of Exemplary Compounds) Examples 2 through 4, 9, 10, 17, 20, and 21 are for reference only. As shown in Tables 5 to 7, the exemplary compounds in Examples 2 to 24 were synthesized in the same manner as in Example 1, except that raw material f-1 was replaced with raw material 1, raw material f-2 with raw material 2, and raw material f-4 with raw material 3. The measured values ​​(m / z) of the mass spectrometry results, measured in the same manner as in Example 1, are also shown.

[0237] [Table 5]

[0238] [Table 6]

[0239] [Table 7]

[0240] [Example 25 (Synthesis of Exemplary Compound A-16)] (Reference example) Exemplary compound A-16 was synthesized according to the following scheme. [ka]

[0241] (1) Synthesis of compound f-7 The following reagents and solvents were placed in a 100 ml round-bottom flask. Compound f-3: 5.10g (20.0mmol) Iridium chloride hydrate: 1.60g Ethoxyethanol: 36ml Water: 12ml Next, the reaction solution was heated and stirred at 130°C under a nitrogen stream for 5 hours. After the reaction was complete, the reaction solution was filtered, and the resulting solid was washed with water and methanol on the filter. 4.3 g of yellow solid (f-7) was obtained (yield: 58%).

[0242] (2) Synthesis of Exemplary Compound A-16 The following reagents and solvents were placed in a 100 ml round-bottom flask. Compound f-7: 1.47g (1.00mmol) Compound f-8: 0.40g (4.00mmol) Sodium carbonate: 1.06g (10.0 mmol) Ethoxyethanol: 30ml Water: 12ml Next, the reaction solution was heated and stirred at 100°C under a nitrogen stream for 6 hours. After cooling, methanol was added, filtered, and washed with methanol. 0.42 g of a yellow solid (exemplary compound A-16) was obtained (yield: 52%).

[0243] For example compound A-16, mass spectrometry was performed using MALDI-TOF-MS (Bruker Autoflex LRF). [MALDI-TOF-MS] Measured value: m / z = 800 Calculated value: C 43 H 32 IrO2N3 = 800

[0244] [Example 26] ~ 30 (Synthesis of Exemplary Compounds) (Examples 26 and 29 are for reference only) As shown in Table 8, the exemplary compounds in Examples 26 to 30 were synthesized in the same manner as in Example 25, except that raw material f-3 was replaced with raw material 1 and raw material f-8 with raw material 2. The measured values ​​(m / z) of the mass spectrometry results, measured in the same manner as in Example 25, are also shown.

[0245] [Table 8]

[0246] [Example 31 (Synthesis of Exemplary Compound E-1)] (Reference example) Exemplary compound E-1 was synthesized according to the following scheme. [ka]

[0247] (1) Synthesis of Exemplary Compound E-1 A 100 ml eggplant flask was charged with the following reagents and solvents. Compound A-16: 0.80 g (1.00 mmol) Compound f-3: 0.64 g (2.50 mmol) Sodium carbonate: 1.06 g (10.0 mmol) Glycerol: 30 ml Next, the reaction solution was degassed with nitrogen and then heated and stirred at 180 °C for 6 hours. After cooling, methanol was added, and the mixture was filtered and washed with methanol. The obtained solid was purified by silica gel column chromatography (toluene: ethyl acetate mixture), and 0.14 g (yield: 15%) of a yellow solid (exemplary compound E-1) was obtained.

[0248] Mass spectrometry was performed on the exemplary compound E-1 using MALDI-TOF-MS (Autoflex LRF manufactured by Bruker). [MALDI-TOF-MS] Measured value: m / z = 955 Calculated value: C 57 H 36 IrN3 = 955

[0249] [Example 32 ~ 33 (Synthesis of Exemplary Compounds)] As shown in Table 9, for the exemplary compounds shown in Examples 32 to 33, the exemplary compounds were synthesized in the same manner as in Example 31, except that starting material A-16 in Example 31 was changed to starting material 1 and starting material f-3 was changed to starting material 2. Also shown are the measured values of m / z of the mass spectrometry results measured in the same manner as in Example 31.

[0250]

Table 9

[0251] [Example 34] An organic light-emitting device with a bottom emission structure in which an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a cathode were sequentially formed on a substrate was fabricated.

[0252] First, an ITO film was deposited on a glass substrate, and an ITO electrode (anode) was formed by applying the desired patterning process. At this time, the film thickness of the ITO electrode was set to 100 nm. The substrate on which the ITO electrode was formed in this way was used as the ITO substrate in the following process. Next, 1.33 × 10 -4 Vacuum deposition was performed by resistance heating in a Pa vacuum chamber to continuously deposit the organic compound layer and electrode layer shown in Table 10 onto the ITO substrate. At this time, the electrode area of ​​the opposing electrodes (metal electrode layer, cathode) was 3 mm². 2 I made it so that it would be like that.

[0253] [Table 10]

[0254] The characteristics of the obtained elements were measured and evaluated. As shown in Table 11, the maximum emission wavelength of the light-emitting element was 529 nm, and the efficiency was 57 cd / A. Furthermore, the current density was 50 mA / cm². 2 A continuous operation test was conducted, and the time it took for the brightness degradation rate to reach 5% was measured.

[0255] In this embodiment, the measuring device specifically measured the current-voltage characteristics with a Hewlett-Packard 4140B micro-ammeter, and the luminous intensity with a Topcon BM7.

[0256] Furthermore, the LUMOs of the host and assist materials are shown in parentheses in Table 11. To calculate the LUMO, the ionization potential (IP) was determined using an AC-3 atmospheric photoelectron spectrometer manufactured by RIKEN KEKI Co., Ltd., and the optical band gap (BG), determined using a UV-Vis spectrophotometer manufactured by JASCO Corporation, was subtracted to calculate the LUMO level.

[0257] [Examples 35 to 41] (Example 41 is a reference example) In Examples 35 to 41, organic light-emitting elements were fabricated in the same manner as in Example 34, except that the materials of the light-emitting layer shown in Table 11 were appropriately changed. The obtained elements were evaluated in the same manner as in Example 34. The time at which the brightness degradation rate reached 5% is shown as a ratio with the time in Example 34 set to 1.0. The measurement results are shown in Table 11. The LUMO of the host material and assist material, calculated in the same manner as in Example 34, is shown in parentheses in Table 11.

[0258] [Table 11]

[0259] In Table 11, the dopant materials of Examples 34 to 36 are compounds of general formula [1] R 11 It is a compound having a tertiary alkyl group with 4 or more carbon atoms. Therefore, the emission wavelength is optimal as green, from 529 nm to 530 nm. On the other hand, the dopant materials of Examples 37 to 40 are compounds of general formula [2] and R 31 It is a compound having a tertiary alkyl group with 4 or more carbon atoms. Therefore, it emits longer wavelength light than the dopant materials of Examples 34 to 36. The dopant material of Example 41 is a compound of general formula [2] with R 31 Because the compound does not have a tertiary alkyl group with 4 or more carbon atoms, the emission wavelength is even longer. In addition, the devices of Examples 34 to 40 show little brightness degradation. This is thought to be because the effects of decomposition during vapor deposition are minimal.

[0260] [Example 42] In Example 34, an organic light-emitting element was fabricated using the same method as in Example 34, except that the materials and film thickness shown in Table 12 were changed. The characteristics of the obtained element were measured and evaluated in the same manner as in Example 34.

[0261] [Table 12]

[0262] The characteristics of the obtained element were measured and evaluated in the same manner as in Example 34. As shown in Table 13, the maximum emission wavelength of the light-emitting element was 530 nm, and the efficiency was 56 cd / A. The LUMO of the host material and assist material, calculated in the same manner as in Example 34, are shown in parentheses in Table 13.

[0263] [Examples 43 to 48, Comparative Examples 1 to 4] In Examples 43 to 48 and Comparative Examples 1 to 4, organic light-emitting devices were fabricated in the same manner as in Example 42, except that the materials of the light-emitting layer shown in Table 13 were appropriately changed. Compounds Q-2-1 and S-4-1 are shown below.

[0264] [ka]

[0265] The obtained elements were evaluated in the same manner as in Example 42. The time at which the brightness degradation rate reached 5% is shown as a ratio with the time in Example 42 set to 1.0. The measurement results are shown in Table 13. The LUMO of the host material and assist material, calculated in the same manner as in Example 42, are shown in parentheses in Table 13.

[0266] [Table 13]

[0267] Table 13 shows that the host materials in Comparative Examples 1 to 4 are nitrogen and oxygen-containing host materials, resulting in lower efficiency and shorter lifespan compared to the devices in Examples 42 to 48, where hydrocarbons are the host material. Furthermore, the devices in Examples 42 to 46 include an assist material with a smaller LUMO than the host material. Therefore, the efficiency of these devices is higher than that of Example 47, which does not include an assist material, and Example 48, which includes an assist material with a larger LUMO than the host material. From this, it can be concluded that by selecting hydrocarbons as the host material and selecting an assist material with a smaller LUMO than the host material, it is possible to provide devices with high efficiency and long lifespan. [Explanation of Symbols]

[0268] 1: Interlayer insulating layer, 2: First electrode, 3: Insulating layer, 4: Organic compound layer, 5: Second electrode, 6: Protective layer, 7: Color filter, 10: Sub-pixel, 11: Substrate, 12: Insulating layer, 13: Gate electrode, 14: Gate insulating film, 15: Semiconductor layer, 16: Drain electrode, 17: Source electrode, 18: TFT, 19: Insulating film, 20: Contact hole, 21: Anode, 22: Organic compound layer, 23: Cathode, 24: First protective layer, 25: Second protective layer, 26: Organic light-emitting element, 100: Display device< / x>

Claims

1. An organic compound characterized by being represented by the following general formula [1] or [2]. 【Transformation 5】 In equations [1] to [2], R 1 ~R 12 , R 21 ~R 32 Each of these is independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heteroaryloxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted silyl group, and a substituted or unsubstituted amino group. However, R 1 ~R 12 At least one of R 21 ~R 32 At least one of them is a tertiary alkyl group having four or more carbon atoms. m represents an integer between 1 and 3 (inclusive), and n represents an integer between 0 and 2 (inclusive). However, m + n is equal to 3. X represents a bidentate ligand, and the substructure IrX is one of the structures shown in the following general formulas [3] to [5]. 【Transformation 6】 In formulas [3] to [5], R 41 to R 55 are each independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heteroaryloxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted silyl group, and a substituted or unsubstituted amino group. Adjacent R 52 to R 55 may be bonded to each other to form a ring.

2. The aforementioned R 9 ~R 12 At least one of the R 29 ~R 32 The organic compound according to claim 1, characterized in that at least one of them is a tertiary alkyl group having 4 or more carbon atoms.

3. The organic compound according to claim 2, characterized in that the tertiary alkyl group having 4 or more carbon atoms is a tertiary butyl group.

4. The organic compound according to any one of claims 1 to 3, characterized by being represented by the general formula [1].

5. The aforementioned R 11 The organic compound according to claim 4, characterized in that the group is a tertiary butyl group.

6. The organic compound according to claim 5, characterized in that it is one of the following compounds. 【Transformation 7】

7. An organic light-emitting element having a first electrode, a second electrode, and a light-emitting layer disposed between the first electrode and the second electrode, The light-emitting layer is characterized by containing an organic compound according to any one of claims 1 to 6.

8. The organic light-emitting element according to claim 7, wherein the light-emitting layer further comprises a host material which is a hydrocarbon compound, and the host material has at least one of a triphenylene ring, a chrysene ring, or a fluorantene ring as its backbone.

9. The organic light-emitting element according to claim 8, wherein the light-emitting layer further comprises an assisting material, and the LUMO of the assisting material is smaller than the LUMO of the host material (further from the vacuum level).

10. The organic light-emitting element according to claim 9, characterized in that the assist material is a compound having any of the following structures in part. 【Transformation 8】 (In the above structure, X represents an oxygen atom, a sulfur atom, or a substituted or unsubstituted carbon atom.)

11. 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 7 to 10 and a transistor connected to the organic light-emitting element.

12. 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 photoelectric conversion device is characterized in that the display unit has an organic light-emitting element as described in any one of claims 7 to 10.

13. An electronic device comprising: a display unit having an organic light-emitting element as described in any one of claims 7 to 10; a housing on which the display unit is provided; and a communication unit provided in the housing for communicating with the outside.

14. A lighting device comprising a light source having an organic light-emitting element as described in any one of claims 7 to 10, and a light-diffusing section or optical filter that transmits light emitted by the light source.

15. A mobile body characterized by comprising a lamp having an organic light-emitting element as described in any one of claims 7 to 10, and a body on which the lamp is provided.

16. A device comprising a photoreceptor and an exposure light source for exposing the photoreceptor, The image forming apparatus is characterized in that the exposure light source has an organic light-emitting element as described in any one of claims 7 to 10.

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