Organic light-emitting devices

Abstract

To provide an organic light-emitting element with high color purity and excellent luminous efficacy.SOLUTION: In an organic light-emitting element, a light-emitting layer contains a dopant material and a host material. The dopant material is a compound represented by general formula [1]. The host material is a hydrocarbon.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention , Yes The present invention relates to an organic light-emitting element. [Background technology]

[0002] An organic light-emitting device (hereinafter sometimes referred to as an "organic electroluminescence device" or "organic EL device") is an electronic device having a pair of electrodes and an organic compound layer disposed between these electrodes. By injecting electrons and holes from this pair of electrodes, excitons of a light-emitting organic compound in the organic compound layer are generated, and when the excitons return to the ground state, the organic light-emitting device emits light. Recent advances in organic light-emitting devices have been remarkable, including low driving voltage, diverse emission wavelengths, fast response, and the ability to reduce the thickness and weight of light-emitting devices. Examples of light-emitting devices that can achieve high efficiency include devices that use highly efficient materials such as phosphorescent materials. Patent Document 1 describes the following compound A-1. Patent Document 2 describes an organic light-emitting device that uses the following compound A-2 as an emitting dopant and the following compound B-1 as a host material. Patent Documents 3 and 4 describe iridium complexes that use ligands represented by the following compounds C-1 and C-2. Patent Document 5 describes an organic light-emitting device that uses the following compound B-2 as a host material.

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

[0004] [Patent Document 1] Chinese Patent Application Publication No. 110294778 [Patent Document 2] Chinese Patent Application Publication No. 111690016 [Patent Document 3] Japanese Patent Application Publication No. 2020-125289 [Patent Document 4] Japanese Patent Application Laid-Open No. 2016-104722 [Patent Document 5] Japanese Patent Application Publication No. 2018-172366 Summary of the Invention [Problem to be solved by the invention]

[0005] When Compound A-1 described in Patent Document 1 is used in an emitting layer of an organic light-emitting device, there is a problem with the luminous efficiency due to the relationship with the host material. Furthermore, the organic light-emitting devices described in Patent Documents 2 and 5 and the organic light-emitting devices using iridium complexes described in Patent Documents 3 and 4 also have a problem with the luminous efficiency. The present invention has been made in view of the above problems, and an object of the present invention is to provide an organic light-emitting element having high color purity and excellent luminous efficiency. [Means for solving the problem]

[0006] The organic light-emitting device of the present invention comprises at least an anode, a light-emitting layer, and a cathode in this order, the light-emitting layer contains at least a dopant material and a host material; The dopant material is a compound represented by the following general formula [1]: The host material is characterized by being a hydrocarbon.

[0007] [ka] In formula [1], R1 to R8 are each independently selected from a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted silyl group, and a substituted or unsubstituted aryl group, provided that R1 to R8 do not include a cyano group. m is an integer between 1 and 3, and n is an integer between 0 and 2, provided that m+n is 3. X represents a bidentate ligand, and the partial structure IrX is any of the structures represented by the following general formulas [2] and [3].

[0008] [ka] In formulas [2] and [3], R9 to R 19 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 alkoxy group, a substituted or unsubstituted silyl group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group. 16 ~R 19 may be bonded to each other to form a ring. Ring A is any of the structures shown in the following general formulas [4] to [7].

[0009] [ka] In formulas [4] to [7], R 20 ~R 29 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 alkoxy group, a substituted or unsubstituted silyl group, and a substituted or unsubstituted aryl group. However, the above R 9 ~R 29 At least one of the groups is a tertiary alkyl group. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide an organic light-emitting device and an organic compound that have high color purity and excellent luminous efficiency. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a diagram illustrating the characteristics of the organic compound of the present invention. [Figure 2] 1A is a schematic cross-sectional view showing an example of a pixel of a display device according to one embodiment of the present invention, and FIG. 1B is a schematic cross-sectional view showing an example of a display device using an organic light-emitting element according to one embodiment of the present invention. [Figure 3] 1 is a schematic diagram illustrating an example of a display device according to an embodiment of the present invention. [Figure 4] (a) A schematic diagram showing an example of an imaging device according to an embodiment of the present invention. (b) A schematic diagram showing an example of an electronic device according to an embodiment of the present invention. [Figure 5] (a) A schematic diagram showing an example of a display device according to an embodiment of the present invention. (b) A schematic diagram showing an example of a foldable display device. [Figure 6] (a) A schematic diagram showing an example of a lighting device according to an embodiment of the present invention. (b) A schematic diagram showing an example of a moving body having a vehicle lamp according to an embodiment of the present invention. [Figure 7] (a) A schematic diagram showing an example of a wearable device according to an embodiment of the present invention. (b) A schematic diagram showing another example of a wearable device according to an embodiment of the present invention. [Figure 8] (a) A schematic diagram showing an example of an image forming device according to an embodiment of the present invention. (b) A schematic diagram showing an example of an exposure light source of the image forming device according to an embodiment of the present invention.

Embodiments for Carrying Out the Invention

[0016] (1) The organic compound and dopant material of the present invention The organic compound and dopant material of the present invention are compounds represented by the following general formula [1]. The organic compound of the present invention is a compound in which at least one of R1 to R8 is a tertiary alkyl group, and the dopant material of the present invention is a compound in which R1 to R8 do not contain a cyano group. In this specification, a coordination bond is indicated by a straight line or an arrow.

[0017]

Chemical Formula

[0018] <R1 to R8> In formula [1], R1 to R8 are each independently selected from a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted silyl group, and a substituted or unsubstituted aryl group. In the organic compound of this embodiment, at least one of R1 to R8 is a tertiary alkyl group. In the dopant material of this embodiment, R1 to R8 do not include a cyano group.

[0019] Examples of the alkyl group include, but are not limited to, a methyl group, an ethyl group, a normal propyl group, an isopropyl group, a normal butyl group, a tertiary butyl group, a secondary butyl group, an octyl group, a cyclohexyl group, a tertiary pentyl group, a 3-methylpentan-3-yl group, a 1-adamantyl group, and a 2-adamantyl group. The alkyl group is preferably an alkyl group having 1 to 10 carbon atoms.

[0020] Examples of the silyl group include, but are not limited to, a trimethylsilyl group and a triphenylsilyl group.

[0021] Examples of aryl groups include, but are not limited to, phenyl, naphthyl, indenyl, biphenyl, terphenyl, fluorenyl, phenanthryl, triphenylenyl, pyrenyl, anthranyl, perylenyl, chrysenyl, and fluoranthenyl groups. Preferred aryl groups have 6 to 30 carbon atoms.

[0022] Examples of substituents that the alkyl group, silyl group, and aryl group may further have include, but are not limited to, a deuterium atom; alkyl groups such as a methyl group, an ethyl group, a normal propyl group, an isopropyl group, a normal butyl group, and a tertiary butyl group; aralkyl groups such as a benzyl group; aryl groups such as a phenyl group and a biphenyl group; a hydroxy group, and a thiol group.

[0023] In the organic compound of this embodiment, it is preferable that R1 to R8 do not contain a cyano group. Also, in the dopant material of this embodiment, it is preferable that at least one of R1 to R8 is a tertiary alkyl group.

[0024] In the organic compound and dopant material of this embodiment, at least one of R1 to R8 is preferably a tertiary butyl group.

[0025] <m,n> In formula [1], m represents an integer of 1 or more and 3 or less, and n represents an integer of 0 or more and 2 or less, provided that m+n is 3. When m is 2 or more, the multiple ligands may be the same or different. When n is 2, the multiple Xs may be the same or different.

[0026] <x> In the formula [1], X represents a bidentate ligand, and the partial structure IrX is any of the structures represented by the following general formulae [2] and [3].

[0027] [ka]

[0028] [R9 to R 19 ] In formulas [2] and [3], R9 to R 19 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 alkoxy group, a substituted or unsubstituted silyl group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group.

[0029] Examples of halogen atoms include, but are not limited to, fluorine, chlorine, bromine, and iodine.

[0030] Examples of alkoxy groups include, but are not limited to, methoxy, ethoxy, isopropoxy, tertiary butoxy, etc. Preferred alkoxy groups are those having 1 to 10 carbon atoms.

[0031] Examples of heterocyclic groups include, but are not limited to, pyridyl, pyrimidyl, pyrazyl, triazyl, benzofuranyl, benzothiophenyl, dibenzofuranyl, dibenzothiophenyl, oxazolyl, oxadiazolyl, thiazolyl, thiadiazolyl, carbazolyl, acridinyl, phenanthrolyl, and thienyl. Preferred heterocyclic groups are those having 3 to 27 carbon atoms.

[0032] R9 to R 19 Specific examples of the alkyl group, silyl group, and aryl group represented by the formula (I) include, but are not limited to, those described for R1 to R8. The alkyl group is preferably an alkyl group having 1 to 10 carbon atoms. The aryl group is preferably an aryl group having 6 to 30 carbon atoms. Specific examples of the substituents that the alkyl group, alkoxy group, silyl group, aryl group, and heterocyclic group may further have include, but are not limited to, those described for R1 to R8 as those substituents that the alkyl group, silyl group, and aryl group may further have.

[0033] Also, adjacent R 16 ~R 19 may be bonded to each other to form a ring. 16 ~R 19 are bonded to each other to form a ring, R 16 and R 17 , R 17 and R 18 , R 18 and R 19 and a ring formed by bonding R 16 ~R 19 This means that the benzene ring to which the R is attached forms a condensed ring. 16 ~R 19 The ring formed by bonding may be an aromatic ring.

[0034] In the organic compound and dopant material of this embodiment, the partial structure IrX is a structure represented by general formula [3], and R 12 ~R 19 are preferably independently selected from a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group, and a substituted or unsubstituted silyl group. 11 At least one of or R 12 ~R 19 At least one of the groups is a tertiary alkyl group, preferably a tertiary butyl group.

[0035] Ring A is any of the structures shown in the following general formulas [4] to [7].

[0036] [ka]

[0037] [R 20 ~R 29 ] In formulas [4] to [7], R 20 ~R 29 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 alkoxy group, a substituted or unsubstituted silyl group, and a substituted or unsubstituted aryl group.

[0038] R 20 ~R 29 Specific examples of the halogen atom, alkyl group, alkoxy group, silyl group, and aryl group represented by the formula (I) include R9 to R 19 Examples of substituents that may be further introduced by the alkyl group, alkoxy group, silyl group, and aryl group include, but are not limited to, those similar to those described in R1 to R8. The alkyl group is preferably an alkyl group having 1 to 10 carbon atoms. The alkoxy group is preferably an alkoxy group having 1 to 10 carbon atoms. The aryl group is preferably an aryl group having 6 to 30 carbon atoms. Specific examples of substituents that may be further introduced by the alkyl group, alkoxy group, silyl group, and aryl group include, but are not limited to, those similar to the substituents that may be further introduced by the alkyl group, silyl group, and aryl group described in R1 to R8.

[0039] In the organic compound and dopant material of this embodiment, ring A preferably has a structure represented by general formula [4], and R 20 is preferably a tertiary butyl group.

[0040] <Features> The compound represented by the general formula [1] of this embodiment has the following characteristics. (1-1) By having a fluorene ring with ring A bonded to the 1-position as a ligand, the half-width of the emission spectrum is narrow and the emission is of high color purity. (1-2) Having a fluorene ring as a ligand provides high hole transport properties. (1-3) R1 to R8 do not have highly polar groups. This is explained below.

[0041] (1-1) By having a fluorene ring with ring A bonded to the 1-position as a ligand, the half-width of the emission spectrum is narrow and the emission is of high color purity.

[0042] The iridium complex of this embodiment has a fluorene ring (1-substituted fluorene ring) as a ligand, with ring A bonded to the 1-position. When ring A has the structure shown in formula [4], R1 and R2, preferably alkyl groups, at the 9-position of the fluorene ring are arranged to sandwich a hydrogen atom on the pyridine ring, as shown in Figure 1a). Because the hydrogen atom on the pyridine ring repels R1 and R2, particularly alkyl groups, on both sides of the fluorene ring, the dihedral angle between the pyridine ring and the fluorene ring is fixed, the rotational energy between the two rings is very high, and rotation of the bond between the pyridine ring and the fluorene ring is suppressed. As a result, vibrational modes due to rotational control are suppressed in the emission spectrum, the half-width of the emission spectrum is narrow, and color purity is high.

[0043] Therefore, in the compound represented by general formula [1] of this embodiment, when ring A has the structure represented by formula [4], the carbon atom at the position marked with an asterisk in Figure 1a) must be unsubstituted, i.e., bonded to a hydrogen atom. Figure 1b) shows the case where the carbon atom at the position marked with an asterisk is bonded to a phenyl group. As shown in Figure 1b), the phenyl group is not sandwiched between the alkyl groups of the fluorene ring, but is positioned outside the alkyl groups. In this case, the dihedral angle between the plane of the fluorene ring and the plane of the pyridine ring becomes very large, resulting in a highly distorted ligand, making synthesis impossible. Furthermore, even if the ligand could be synthesized, it would be impossible to form a complex with iridium metal.

[0044] When ring A has a structure represented by any of formulas [5] to [7], the lone electron pair at the position corresponding to the star in Figure 1a) functions in the same way as a hydrogen atom, and the same effect can be obtained.

[0045] (1-2) Having a fluorene ring as a ligand provides high hole transport properties.

[0046] The iridium complexes represented by the general formula [1] have high hole transport properties due to the fluorene rings in the ligands. This is thought to be due to the structure in which the fluorene rings of the ligands easily overlap, facilitating hole hopping between the ligands.

[0047] (1-3) R1 to R8 do not have highly polar groups.

[0048] As described in (2-1), the light-emitting device of this embodiment is characterized in that the dopant material of the light-emitting layer is a compound represented by general formula [1], and the host material is a hydrocarbon. This results in a strong interaction between the dopant material and the host material, facilitating energy transfer. That is, the short intermolecular distance between the host material and the dopant material results in efficient energy transfer from the host material to the dopant material. The dopant material has a fluorene ring, which is a fused ring structure with low polarity and aromaticity, in the ligand. Therefore, a hydrocarbon, preferably a hydrocarbon-based fused ring structure, is introduced into the host to facilitate ππ interaction between the host and the dopant ligand, facilitating energy transfer from the host to the dopant.

[0049] In order to obtain the above effect, it is preferable that R1 to R8 are groups with low polarity. 20 ~R 29 is more preferably a group with low polarity. Specific examples of the group with low polarity include a hydrogen atom, a deuterium atom, an alkyl group composed of a hydrocarbon, and an aryl group. The presence of a group with low polarity reduces the polarity of the iridium complex, making it less likely for molecular association between iridium complexes in the host material. This makes it less likely for ππ interactions with the host material to be inhibited. Furthermore, concentration quenching is less likely to occur. As a result, energy transfer from the host material to the dopant material is facilitated and concentration quenching is less likely to occur, improving the luminous efficiency of the organic light-emitting device. Examples of groups with high polarity include azine rings such as a cyano group, a halogen group, and a pyridyl group. Specific examples include ligands with the following structures:

[0050] [ka]

[0051] Furthermore, the compound represented by the general formula [1] of this embodiment preferably has the following characteristics. (1-4) Sublimation is improved when the auxiliary ligand X is a ligand with low planarity. (1-5) At least one of R1 to R8 or R 20 ~R 29 When at least one of the groups is a tertiary alkyl group, the sublimation property is improved. This is explained below.

[0052] (1-4) Sublimation is improved when the auxiliary ligand X is a ligand with low planarity.

[0053] The compound represented by general formula [1] of this embodiment has at least one ligand having a 1-substituted fluorene ring (1-substituted fluorene ligand) and may have an auxiliary ligand X. Because the 1-substituted fluorene ligand of this embodiment has high planarity, it is preferable to have an auxiliary ligand X that does not further enhance the planarity. The reason for this is that, as described in (1-1), the 1-substituted fluorene ligand of the compound represented by general formula [1] of this embodiment has ring A bonded to the 1-position of the fluorene ring, thereby fixing the dihedral angle between ring A and the fluorene ring, resulting in a narrow half-width of the emission spectrum and high color purity. On the other hand, the planarity of the 1-substituted fluorene ligand is high. Therefore, when the planarity of the auxiliary ligand X is low, stacking between the complexes is weakened, making concentration quenching in the light-emitting layer less likely. This narrows the half-width of the emission spectrum and improves luminous efficiency. Furthermore, the temperature rise during sublimation purification by stacking and vacuum deposition is reduced, making it difficult for the complex to decompose.

[0054] Therefore, when high sublimability is required, it is preferable that the auxiliary ligand X is a ligand with low planarity. Specifically, in the general formulas [2] and [3], R9 and R 19 is preferably a group that does not enhance the planarity, such as a hydrogen atom, an alkyl group, or a silyl group. 19 are preferably 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 alkoxy group, and a substituted or unsubstituted silyl group. 19 are each preferably independently selected from a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group, and a substituted or unsubstituted silyl group. 11 or R 12 ~R 19 Preferably, one or more of the following groups is a tertiary alkyl group. Having a tertiary alkyl group in the auxiliary ligand X reduces stacking of the complex, and has the effect of lowering the temperature during sublimation purification and vacuum deposition. As the tertiary alkyl group, a tertiary alkyl group having 4 or more carbon atoms is preferred, and a tertiary butyl group is more preferred.

[0055] Table 1 shows the sublimation temperature and sublimation purification yield during sublimation purification of each compound. Compounds 1 to 3 are the exemplified compounds F-1 and J-16 described later, and compound A-1 described in Patent Document 1, respectively. The degree of vacuum during sublimation purification was 1×10 -3 Pa to 1 x 10 -2 Pa. As can be seen from Table 1, the planarity of the auxiliary ligand X in compound 1 is lower than in compounds 2 and 3, where the auxiliary ligand X has a xanthene ring or a biphenyl ring, resulting in a lower sublimation temperature and a higher yield during sublimation purification.

[0056] [Table 1]

[0057] (1-5) At least one of R1 to R8 or R 20 ~R 29 When at least one of the groups is a tertiary alkyl group, the sublimation property is improved.

[0058] The iridium complex of this embodiment has the above-mentioned characteristics due to the presence of a fluorene ring in the ligand, but the presence of a fused polycyclic ring may result in a large molecular weight of the complex, which may cause poor sublimation. Specifically, the temperature during sublimation purification may be high, or the complex may be partially decomposed after sublimation purification. Therefore, at least one of R1 to R8 or R 20 ~R 29 At least one of (R 20 ~R 22 , R 23 ~R 25 , R 26 ~R 27 or R 28 ~R 29 Preferably, at least one of the groups is a tertiary alkyl group. This suppresses molecular stacking between complexes, lowering the sublimation temperature. If the tertiary alkyl group has four or more carbon atoms, it has a large effect of excluding complexes from each other, and is highly effective in suppressing molecular stacking. By having a tertiary alkyl group, it is possible to reduce radical cleavage of hydrogen at the benzyl position due to temperature when the temperature load is high.

[0059] Table 2 shows the bond dissociation energies of carbon-hydrogen bonds described in ACC. Chem. Res. 36, 255-263, (2003).

[0060] [Table 2]

[0061] A larger bond dissociation energy value indicates a stronger bond, and a smaller value indicates a weaker bond. In other words, it can be seen that the carbon-hydrogen bond at the benzylic position is a weak bond. This is because when the hydrogen atom at the benzylic position is eliminated to form a radical, the radical is stabilized by resonance with the π electrons of the adjacent benzene ring. For this reason, the carbon-hydrogen bond at the benzylic position is a weak bond. In other words, if a structure such as a benzyl group is not present in the molecular structure, the compound will have a carbon-hydrogen bond that is less likely to be broken, which is preferable.

[0062] In addition, the iridium complex represented by the general formula [1] of this embodiment has a high hole transport property due to the presence of a fluorene ring in the ligand. This is thought to be due to the structure in which the fluorene rings of the ligands tend to overlap with each other, making it easy for holes to hop between the ligands. Therefore, in order to prevent the overlapping of the fluorene rings from decreasing, the ring A side, i.e., R 20 ~R 29 It is more preferable that at least one of them is a tertiary alkyl group.

[0063] <Example> Specific examples of the organic compound and dopant material of this embodiment are shown below, but of course, the present invention is not limited to these. (D-1, 4 to 11, 13, 15, E-4, 10, 15, F-1, 4 to 11, 13, 15, G-10, 15, H-1 to 5, I-3, J-1, 3 to 5, 16, 18, 20, 23, 28, K-1, 3, 6, 9, 11, 13 to 15 are examples) .

[0064] [ka]

[0065] [ka]

[0066] [ka]

[0067] [ka]

[0068] [ka]

[0069] [ka]

[0070] [ka]

[0071] [ka]

[0072] The exemplary compounds belonging to group D are compounds in which m is 2 in general formula [1] and ring A has a structure represented by general formula [4]. The presence of two highly planar fluorene rings results in high hole mobility and a high degree of orientation of the compound, improving the light extraction of the light-emitting device.

[0073] The exemplary compounds belonging to group E are those in which, in general formula [1], m is 2, ring A has a structure represented by general formula [4], and R1 to R8, R 20 ~R 22 At least one of the groups is a tertiary alkyl group. By reducing intermolecular stacking, sublimation is improved and concentration quenching in the light-emitting layer can be suppressed.

[0074] The exemplary compounds belonging to group F are compounds in which m is 1 in general formula [1] and ring A has the structure shown in general formula [4]. The highly planar fluorene ring provides high hole mobility. In addition, compared to compounds belonging to group D, the molecular weight is lower and the sublimation temperature is lower.

[0075] The exemplary compounds belonging to group G are those in which, in general formula [1], m is 1, ring A has a structure represented by general formula [4], and R1 to R8, R 20 ~R 22 At least one of the groups is a tertiary alkyl group. Compared to the compounds in group F, this compound has reduced intermolecular stacking, which improves sublimation and suppresses concentration quenching in the light-emitting layer.

[0076] The exemplary compounds belonging to the H and I groups are compounds in which m is 3 in the general formula [1] and ring A has the structure shown in general formula [4]. The presence of three highly planar fluorene rings results in extremely high hole mobility.

[0077] The exemplary compounds belonging to Group J are compounds in which, in the general formula [1], m is 1 or 2, ring A has a structure represented by the general formula [4], and has a highly planar ligand as the auxiliary ligand X. The presence of a highly planar ligand results in extremely high hole mobility.

[0078] Exemplary compounds belonging to Group K are compounds in which, in general formula [1], m is 1, 2, or 3, and ring A has any of the structures shown in general formulas [5] to [7]. They have high electron-withdrawing properties and good carrier balance in the device.

[0079] (2) Characteristics of organic light-emitting devices The organic light-emitting device of the present invention comprises at least an anode, a light-emitting layer, and a cathode in this order, the light-emitting layer containing at least a dopant material and a host material, and has the following characteristics. (2-1) The dopant material of the light-emitting layer is a compound represented by the general formula [1], and the host material is a hydrocarbon, so that the interaction between the dopant material and the host material is strong and energy transfer is easy. (2-2) The effect of (2-1) above is to promote the transport hopping of holes between the dopant material and the host material, thereby improving the hole transportability in the light-emitting layer. This is explained below.

[0080] (2-1) The dopant material of the light-emitting layer is a compound represented by the general formula [1], and the host material is a hydrocarbon, so that the interaction between the dopant material and the host material is strong and energy transfer is easy.

[0081] The compound represented by general formula [1] has a fluorene ring, which is a fused polycyclic ring composed of hydrocarbons with three fused rings, as a ligand. On the other hand, a hydrocarbon, preferably a fused polycyclic compound, is used as the host material. The dopant material has a fused ring structure in the ligand, which is low in polarity and aromatic. Therefore, by introducing a hydrocarbon, preferably a fused polycyclic group, into the host, which facilitates ππ interactions between the host and dopant ligands, energy transfer from the host to the dopant becomes easier.

[0082] It is known that triplet energy used in phosphorescent light-emitting devices undergoes energy transfer via the Dexter mechanism. The Dexter mechanism involves energy transfer through molecular contact. In other words, shortening the intermolecular distance between the host material and the dopant material results in efficient energy transfer from the host material to the dopant material. The dopant material has a fused ring structure in the ligand that is low in polarity and aromatic. Therefore, a hydrocarbon, preferably a hydrocarbon-based fused ring structure, is introduced into the host to facilitate ππ interactions between the host and dopant ligands, facilitating energy transfer from the host to the dopant.

[0083] The above effects allow triplet excitons generated in the host material to be quickly consumed for light emission, resulting in highly efficient light emission. Furthermore, material degradation due to high-energy triplet excited states that occur when triplet excitons not used for light emission are further excited can be prevented, resulting in good driving durability of the organic light-emitting device.

[0084] The concentration of the dopant material is preferably 0.01% by mass or more and 30% by mass or less, and more preferably 2% by mass or more and 20% by mass or less, based on the total mass of the light-emitting layer.

[0085] (2-2) The effect of (2-1) above is to promote the transport hopping of holes between the dopant material and the host material, thereby improving the hole transportability in the light-emitting layer.

[0086] The compound represented by general formula [1] has a low HOMO level (close to the vacuum level) due to the effect of the fluorene ring in the ligand, and therefore tends to have a lower HOMO level than the host material. Holes injected from the hole-transport layer are transported by the host material, but the holes are transported by repeatedly trapping and detrapping between the dopant material and the host material. In this case, it is preferable to use similar skeletons for the host material and the dopant material. In this case, the fused rings of the host material and the dopant material overlap closely, allowing for efficient hole transfer between the dopant material and the host material. This suppresses voltage rise in the light-emitting layer, providing an organic light-emitting device with good driving durability at low voltages.

[0087] Furthermore, the organic light-emitting device of this embodiment preferably has the following features. (2-3) The light-emitting layer further contains an assist material. The LUMO level of the assist material is preferably lower (farther from the vacuum level) than the LUMO level of the host material. This allows both electron and hole carriers to be confined in the light-emitting layer, providing a highly efficient device. (2-4) The effect of (2-3) above reduces the injection of carriers into the adjacent transport layer through the light-emitting layer, thereby reducing the deterioration of the transport layer, thereby providing a highly durable element. This is explained below.

[0088] (2-3) The light-emitting layer further contains an assist material. The LUMO level of the assist material is preferably lower (farther from the vacuum level) than the LUMO level of the host material. This allows both electron and hole carriers to be confined in the light-emitting layer, providing a highly efficient device.

[0089] The iridium complex represented by general formula [1] promotes hole injection into the light-emitting layer, so 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 electron injection into the light-emitting layer. Because the host material is a hydrocarbon, it has a wide band gap. Therefore, the host material has a high LUMO level (close to the vacuum level), which may make it difficult to inject electrons from the electron transport layer or hole blocking layer. Therefore, to facilitate electron injection into the light-emitting layer, it is preferable to further include an assist material. Furthermore, it is preferable that the LUMO level of the assist material is lower than the LUMO level of the host material. This improves the injection of both holes and electrons into the light-emitting layer, maintaining carrier balance in the light-emitting layer and providing a highly efficient light-emitting device.

[0090] (2-4) The effect of (2-3) above reduces the injection of carriers into the adjacent transport layer through the light-emitting layer, thereby reducing the deterioration of the transport layer, thereby providing a highly durable element.

[0091] As described above, the device of this embodiment exhibits the effect of promoting hole injection in the light-emitting layer by the dopant material and confining holes in the light-emitting layer by the hole trap, thereby preventing holes from being injected from the light-emitting layer into the hole-blocking layer or the electron-transporting layer and reducing deterioration of the hole-blocking layer or the electron-transporting layer due to holes.

[0092] In addition, the assist material, which has a lower LUMO level than the host material, promotes electron injection and traps electrons in the light-emitting layer, reducing the injection of electrons from the light-emitting layer into the electron blocking layer and hole transport layer, and reducing the deterioration of the electron blocking layer and hole transport layer due to electrons.

[0093] (3) Host material The host material is a hydrocarbon. The host material preferably has a T1 (lowest triplet excitation energy) higher than that of the iridium complex represented by general formula [1]. Specifically, since the dopant material of this embodiment emits light in the 500 nm to 540 nm region, T1 is preferably 2.3 eV or higher, more preferably 2.5 eV or higher. Furthermore, as described above, in order to enhance the interaction between the fluorene ring of the ligand of the iridium complex and the host material, the host material is preferably a fused polycyclic compound. Specifically, fused polycyclic groups having a T1 of 2.3 eV or higher include fluoranthene, benzo[e]pyrene, benzo[g]chrysene, benzo[c]chrysene, coronene, benzofluorene, chrysene, picene, naphthalene, phenanthrene, triphenylene, and fluorene. Chrysene, picene, naphthalene, phenanthrene, triphenylene, and fluorene having a T1 of 2.5 eV or higher are preferred.

[0094] Furthermore, the host material of the present invention preferably has the following characteristics. (3-1) The skeleton contains at least one of a chrysene ring, a picene ring, a phenanthrene ring, a triphenylene ring, and a fluoranthene ring. (3-2)SP 3 It has no carbon. The above will be explained below.

[0095] (3-1) The skeleton contains at least one of a chrysene ring, a picene ring, a phenanthrene ring, a triphenylene ring, and a fluoranthene ring.

[0096] The dopant material of this embodiment has a fluorene skeleton in the ligand. The fluorene skeleton has a highly planar structure. As described above in (2-1) and (2-2), in order for the iridium complex of this embodiment and the host material to interact with each other, it is preferable that the host material also have a highly planar structure. This is because a highly planar structure allows highly planar moieties to approach each other through interaction. More specifically, the fluorene moiety of the iridium complex and the planar moiety of the host material are more likely to approach each other. This is expected to shorten the intermolecular distance between the iridium complex and the host material. The above effects lead to the effect of increasing the efficiency of energy transfer described in (2-1).

[0097] Here, examples of highly planar structures include structures containing fused polycyclic rings of three or more rings, and preferred are structures containing fused polycyclic rings that are hydrocarbons such as chrysene rings, picene rings, phenanthrene rings, triphenylene rings, and fluoranthene rings, which are fused polycyclic rings having a T1 of 2.5 eV or more.

[0098] Furthermore, the host material preferably has a ring other than a fluorene ring that has the same structure as the ligand of the iridium complex so as to strongly interact with the iridium complex of this embodiment and not to shift the emission wavelength of the iridium complex to a longer wavelength.

[0099] (3-2)SP 3 It has no carbon.

[0100] As described in the above explanation (3-1), the dopant material of this embodiment is a compound characterized by improving the interaction and luminescence characteristics by improving the distance from the host material. 3 By using a material that does not contain carbon, the distance to the iridium complex can be shortened.

[0101] <Example> Specific examples of the host material are shown below, but the present invention is not limited to these.

[0102] [ka]

[0103] [ka]

[0104] The exemplary host compounds are those having at least one of a triphenylene ring, a naphthalene ring, a phenanthrene ring, a chrysene ring, and a fluoranthene ring in the skeleton, and SP 3 These compounds are compounds that do not contain carbon. Therefore, these compounds can be brought closer to the dopant material of this embodiment, and therefore have a strong interaction, making them host materials that transfer energy well to the dopant material of this embodiment. Among these, compounds that have a triphenylene ring in the skeleton have high planarity and are particularly preferred.

[0105] (4) Assist materials The light-emitting layer preferably further contains an assist material, which is preferably a compound partially having any one of the following structures:

[0106] [ka]

[0107] (In the above structure, X' represents an oxygen atom, a sulfur atom, or a substituted or unsubstituted carbon atom.) The above structure is effective because it has electron-withdrawing properties and can lower the LUMO level of the assist material. The iridium complex represented by general formula [1] has a high HOMO level and tends to trap holes easily, while its LUMO level is high and tends to trap electrons poorly. Therefore, by including an assist material with a low LUMO level in the light-emitting layer, electrons can be trapped in the light-emitting layer, providing a device with an appropriate carrier balance, resulting in high efficiency and long life.

[0108] An assist material having the above structure as a partial structure is preferable because it is considered unlikely to form an exciplex with the dopant material of this embodiment due to its moderately high electron-withdrawing property and moderate size. Examples of assist materials that are considered likely to form an exciplex with the dopant material of this embodiment include compounds having a triazine ring as a partial structure.

[0109] The above structure may be unsubstituted or substituted. The carbon atom represented by X' may be unsubstituted or substituted. Examples of the substituent include a halogen atom, an alkyl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, an aryl group, a heterocyclic group, a silyl group, and an amino group.

[0110] Examples of halogen atoms include, but are not limited to, fluorine, chlorine, bromine, and iodine.

[0111] Examples of the alkyl group include, but are not limited to, a methyl group, an ethyl group, a normal propyl group, an isopropyl group, a normal butyl group, a tertiary butyl group, a secondary butyl group, an octyl group, a cyclohexyl group, a 1-adamantyl group, and a 2-adamantyl group.

[0112] Examples of alkoxy groups include, but are not limited to, methoxy, ethoxy, propoxy, 2-ethyl-octyloxy, and benzyloxy groups.

[0113] Examples of the aryloxy group include, but are not limited to, a phenoxy group and a naphthoxy group.

[0114] Examples of heteroaryloxy groups include, but are not limited to, furanyloxy groups and thienyloxy groups.

[0115] Examples of aryl groups include, but are not limited to, phenyl, naphthyl, indenyl, biphenyl, terphenyl, fluorenyl, phenanthryl, triphenylenyl, pyrenyl, anthranyl, perylenyl, chrysenyl, and fluoranthenyl groups.

[0116] 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.

[0117] Examples of the silyl group include, but are not limited to, a trimethylsilyl group and a triphenylsilyl group.

[0118] Examples of the amino group include, but are not limited to, an N-methylamino group, an N-ethylamino group, an N,N-dimethylamino group, an N,N-diethylamino group, an N-methyl-N-ethylamino group, an N-benzylamino group, an N-methyl-N-benzylamino group, an N,N-dibenzylamino group, an anilino group, an N,N-diphenylamino group, an N,N-dinaphthylamino group, an N,N-difluorenylamino group, an N-phenyl-N-tolylamino group, an N,N-ditolylamino group, an N-methyl-N-phenylamino group, an N,N-dianisolylamino group, an N-mesityl-N-phenylamino group, an N,N-dimesitylamino group, an N-phenyl-N-(4-tert-butylphenyl)amino group, an N-phenyl-N-(4-trifluoromethylphenyl)amino group, an N-piperidyl group, a carbazolyl group, and an acridyl group.

[0119] Examples of substituents that the alkyl group, alkoxy group, aryloxy group, heteroaryloxy group, aryl group, heterocyclic group, silyl group, and amino group may further have include, but are not limited to, deuterium, alkyl groups such as methyl group, ethyl group, normal propyl group, isopropyl group, normal butyl group, and tertiary 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, and cyano group.

[0120] <Example> Specific examples of the assist material are shown below, but the present invention is not limited to these.

[0121] [ka]

[0122] [ka]

[0123] [ka]

[0124] The concentration of the assist material is preferably 0.1% by mass or more and 45% by mass or less, and more preferably 5% by mass or more and 40% by mass or less, based on the total mass of the light-emitting layer.

[0125] (5) Details of organic light-emitting devices The organic light-emitting element of this embodiment has at least a first electrode, a second electrode, and an organic compound layer disposed between these electrodes. One of the first electrode and the second electrode is an anode and the other is a cathode. In the organic light-emitting element of this embodiment, the organic compound layer may be a single layer or a laminate consisting of multiple layers, as long as it has an emitting layer. Here, when the organic compound layer is a laminate consisting of multiple layers, the organic compound layer may have, in addition to the emitting layer, a hole injection layer, a hole transport layer, an electron blocking layer, a hole / exciton blocking layer, an electron transport layer, an electron injection layer, etc. Furthermore, the emitting layer may be a single layer or a laminate consisting of multiple layers.

[0126] In the organic light-emitting device of this embodiment, at least one of the organic compound layers contains the organic compound of this embodiment. Specifically, the organic compound of this embodiment is contained in any of the above-mentioned light-emitting layer, hole injection layer, hole transport layer, electron blocking layer, hole / exciton blocking layer, electron transport layer, electron injection layer, etc. The organic compound of this embodiment is preferably contained in the light-emitting layer.

[0127] In the organic light-emitting device of this embodiment, when the organic compound according to this embodiment is contained in the light-emitting layer, the light-emitting layer may be a layer consisting solely of the organic compound according to this embodiment, or may be a layer consisting of the organic compound according to this embodiment and other compounds. Here, when the light-emitting layer is a layer consisting of the organic compound according to this embodiment and other compounds, the organic compound according to this embodiment may be used as a host or a guest (dopant) of the light-emitting layer. It may also be used as an assist material that can be contained in the light-emitting layer. Here, the host is the compound with the largest mass ratio among the compounds constituting the light-emitting layer. The guest is a compound with a mass ratio smaller than that of the host among the compounds constituting the light-emitting layer, and is responsible for the main emission of light. The assist material is a compound with a mass ratio smaller than that of the host among the compounds constituting the light-emitting layer, and assists the emission of the guest. The assist material is also called a second host. The host material can also be called a first compound, and the assist material can also be called a second compound.

[0128] 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 30% by mass or less, and more preferably 2% by mass or more and 20% by mass or less, based on the total mass of the light-emitting layer.

[0129] The present inventors have conducted various studies and found that when the organic compound according to this embodiment is used as a host or guest in the light-emitting layer, particularly as a guest in the light-emitting layer, a device exhibiting high efficiency and high luminance light output and extremely high durability can be obtained. This light-emitting layer may be a single layer or multiple layers, and it is also possible to mix colors by including a light-emitting material having another light-emitting color. Multiple layers refer to a state in which the light-emitting layer and another light-emitting layer are stacked. In this case, the light-emitting color of the organic light-emitting element is not particularly limited. More specifically, it may be white or a neutral color. In the case of white, the other light-emitting layer emits a color different from the light-emitting color of the light-emitting layer. Furthermore, the film is formed by vapor deposition or coating. Details of this will be explained in detail in the examples below.

[0130] The organic compound according to this embodiment can be used as a constituent material of an organic compound layer other than the light-emitting layer that constitutes the organic light-emitting device of this embodiment. Specifically, it may be used as a constituent material of an electron transport layer, an electron injection layer, a hole transport layer, a hole injection layer, a hole blocking layer, etc. In this case, the emission color of the organic light-emitting device is not particularly limited. More specifically, it may emit white light or a neutral color.

[0131] <Compounds other than the organic compound of this embodiment> In addition to the organic compound according to this embodiment, conventionally known low-molecular-weight and high-molecular-weight hole-injecting or hole-transporting compounds, host compounds, light-emitting compounds, electron-injecting or electron-transporting compounds, etc. may also be used together as needed. Examples of these compounds are listed below.

[0132] As the hole injection and transport material, a material with high hole mobility is preferred so that holes can be easily injected from the anode and the injected holes can be transported to the light-emitting layer. Furthermore, a material with a high glass transition temperature is preferred to suppress deterioration of film quality, such as crystallization, in organic light-emitting devices. Examples of low-molecular-weight and high-molecular-weight materials with hole injection and transport properties include triarylamine derivatives, arylcarbazole derivatives, phenylenediamine derivatives, stilbene derivatives, phthalocyanine derivatives, porphyrin derivatives, poly(vinylcarbazole), poly(thiophene), and other conductive polymers. Furthermore, the above-mentioned hole injection and transport materials are also suitable for use in electron blocking layers. Specific examples of compounds that can be used as hole injection and transport materials are listed below, but the present invention is not limited to these.

[0133] [ka]

[0134] Among the hole transport materials listed above, HT16 to HT18 can reduce the driving voltage when used in a 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 an organic compound layer adjacent to HT16. Furthermore, multiple materials may be used in one organic compound layer.

[0135] Examples of light-emitting materials that are primarily involved in light-emitting function 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-quinolinolato)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 that can be used as light-emitting materials are listed below, but the present invention is not limited to these.

[0136] [ka]

[0137] [ka]

[0138] When the light-emitting material is a hydrocarbon compound, this is preferable because it can reduce the decrease in luminous efficiency due to exciplex formation and the decrease in color purity due to changes in the emission spectrum of the light-emitting material due to exciplex formation. Hydrocarbon compounds are compounds composed only of carbon and hydrogen, and among the above-mentioned exemplified compounds, BD7, BD8, GD5 to GD9, and RD1 are examples. When the light-emitting material is a fused polycyclic ring containing a five-membered ring, this is preferable because it has a high ionization potential, is resistant to oxidation, and results in an element with a long and durable lifespan. Among the above-mentioned exemplified compounds, BD7, BD8, GD5 to GD9, and RD1 are examples.

[0139] Examples of the light-emitting layer host or light-emitting assist material contained in the light-emitting layer include aromatic hydrocarbon compounds or derivatives thereof, as well as carbazole derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, organoaluminum complexes such as tris(8-quinolinolato)aluminum, and organic beryllium complexes. Specific examples of compounds used as the light-emitting layer host or light-emitting assist material contained in the light-emitting layer are shown below, but the present invention is not limited to these.

[0140] [ka]

[0141] When the host material is a hydrocarbon compound, the organic compound of this embodiment is more likely to trap electrons and holes, which is preferable because it significantly improves efficiency. Hydrocarbon compounds are compounds composed only of carbon and hydrogen, and among the above-mentioned exemplary compounds, EM1 to EM26 are examples.

[0142] The electron transport material can be arbitrarily selected from those capable of transporting electrons injected from the cathode to the light-emitting layer, and is selected taking into consideration the balance with the hole mobility of the hole transport material. Examples of materials having electron transport properties include oxadiazole derivatives, oxazole 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 transport materials are also suitable for use in hole-blocking layers. Specific examples of compounds used as electron transport materials are shown below, but of course, the present invention is not limited to these.

[0143] [ka]

[0144] The electron injection material can be selected from those that allow easy electron injection from the cathode, taking into consideration the balance with hole injection properties, etc. Organic compounds include n-type dopants and reducing dopants. Examples include compounds containing alkali metals such as lithium fluoride, lithium complexes such as lithium quinolinol, benzimidazolidene derivatives, imidazolidene derivatives, fulvalene derivatives, and acridine derivatives. They can also be used in combination with the above-mentioned electron transport materials.

[0145] <Configuration of organic light-emitting element> The organic light-emitting element is provided by forming an insulating layer, a first electrode, an organic compound layer, and a second electrode on a substrate. A protective layer, a color filter, a microlens, etc. may be provided on the second electrode. When a color filter is provided, a planarizing layer may be provided between the color filter and the protective layer. The planarizing layer may be made of an acrylic resin, etc. The same applies when a planarizing layer is provided between the color filter and the microlens.

[0146] [substrate] Examples of the substrate include quartz, glass, a silicon wafer, a resin, and a metal. Furthermore, the substrate may be provided with a switching element such as a transistor and wiring, and an insulating layer thereon. Any material can be used for the insulating layer, as long as it allows for the formation of a contact hole so that wiring can be formed between the first electrode and the insulating layer, and ensures insulation from wiring that is not connected. For example, resins such as polyimide, silicon oxide, silicon nitride, etc. can be used.

[0147] [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 a higher potential is the anode, and the other is the cathode. It can also be said that the electrode that supplies holes to the light-emitting layer is the anode, and the electrode that supplies electrons is the cathode.

[0148] The anode material should have as high a work function as possible. Examples include simple metals such as gold, platinum, silver, copper, nickel, palladium, cobalt, selenium, vanadium, and tungsten, mixtures containing these metals, alloys of these metals, and metal oxides such as tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), and zinc indium oxide. Conductive polymers such as polyaniline, polypyrrole, and polythiophene can also be used.

[0149] These electrode materials may be used alone or in combination of two or more. The anode may be composed of one layer or multiple layers.

[0150] When used as a reflective electrode, for example, chromium, aluminum, silver, titanium, tungsten, molybdenum, or alloys or laminates thereof can be used. The above materials can also function as a reflective film without functioning as an electrode. When used as a transparent electrode, transparent conductive oxide layers such as indium tin oxide (ITO) and indium zinc oxide can be used, but are not limited to these. Photolithography techniques can be used to form the electrode.

[0151] On the other hand, materials with a low work function are preferred for the cathode. Examples include alkali metals such as lithium, alkaline earth metals such as calcium, and metals such as aluminum, titanium, manganese, silver, lead, and chromium, as well as mixtures containing these metals. Alternatively, alloys combining these metals can 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 can be used alone or in combination. The cathode can have either 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 critical as long as silver aggregation can be reduced. For example, the silver:other metal ratio can be 1:1, 3:1, or the like.

[0152] 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 DC and AC sputtering methods are more preferred because they provide good film coverage and make it easier to reduce resistance.

[0153] [Organic compound layer] The organic compound layer may be formed as a single layer or as multiple layers. When multiple layers are included, they may be called hole injection layer, hole transport layer, electron blocking layer, light-emitting layer, hole blocking layer, electron transport layer, or electron injection layer depending on their functions. The organic compound layer is mainly composed of organic compounds but may also contain inorganic atoms or inorganic compounds. For example, the organic compound layer may contain copper, lithium, magnesium, aluminum, iridium, platinum, molybdenum, zinc, or the like. The organic compound layer may be disposed between the first electrode and the second electrode, or may be disposed in contact with the first electrode and the second electrode.

[0154] The organic compound layers (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 device according to one embodiment of the present invention are formed by the method shown below.

[0155] The organic compound layer constituting the organic light-emitting device according to one embodiment of the present invention can be formed by dry processes such as vacuum deposition, ionization deposition, sputtering, plasma, etc. Alternatively to the dry process, a wet process can be used in which the compound is dissolved in an appropriate solvent and a layer is formed by a known coating method (for example, spin coating, dipping, casting, LB method, inkjet method, etc.).

[0156] Here, when a layer is formed by a vacuum deposition method or a solution coating method, crystallization is unlikely to occur and the layer has excellent stability over time. When a film is formed by a coating method, the film can be formed by combining with an appropriate binder resin.

[0157] Examples of the binder resin include, but are not limited to, polyvinylcarbazole resin, polycarbonate resin, polyester resin, ABS resin, acrylic resin, polyimide resin, phenol resin, epoxy resin, silicone resin, and urea resin.

[0158] These binder resins may be used singly or in combination as homopolymers or copolymers, and may further contain known additives such as plasticizers, antioxidants, and ultraviolet absorbers, if necessary.

[0159] [Protective layer] A protective layer may be provided on the second electrode. For example, by adhering glass with a moisture absorbent on the second electrode, the infiltration of water and other contaminants 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 infiltration of water and other contaminants into the organic compound layer. For example, after forming the second electrode, the second electrode may be transferred to another chamber without breaking the vacuum, and a 2 μm-thick silicon nitride film may be formed by CVD to serve as a protective layer. A protective layer may be provided using atomic layer deposition (ALD) after the CVD film formation. The material of the film formed by ALD is not limited, and may be silicon nitride, silicon oxide, aluminum oxide, or the like. Silicon nitride may be further formed on the film formed by ALD by CVD. The film formed by ALD may have a thickness smaller than that of the film formed by CVD. Specifically, the thickness may be 50% or less, or even 10% or less.

[0160] [Color Filter] A color filter may be provided on the protective layer. For example, a color filter taking into consideration the size of the organic light-emitting element may be provided on a separate substrate and then bonded to the substrate on which the organic light-emitting element is provided, or a color filter may be patterned on the protective layer described above using photolithography technology. The color filter may be made of a polymer.

[0161] [Planarization layer] A planarization layer may be provided between the color filter and the protective layer. The planarization layer is provided for the purpose of reducing the unevenness of the underlying layer. It may also be called a material resin layer without limiting its purpose. The planarization layer may be composed of an organic compound, and may be either a low molecular weight or a high molecular weight, but a high molecular weight is preferred.

[0162] The planarizing layer may be provided above or below the color filter, and may be made of the same or different materials, such as polyvinyl carbazole resin, polycarbonate resin, polyester resin, ABS resin, acrylic resin, polyimide resin, phenol resin, epoxy resin, silicone resin, and urea resin.

[0163] [Microlens] The organic light-emitting element or organic light-emitting device may have an optical component such as a microlens on its light-emitting side. The microlens may be made of acrylic resin, epoxy resin, or the like. The microlens may be intended 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. The microlens may have a hemispherical shape. When the microlens has a hemispherical shape, among the tangents to the hemisphere, there is a tangent that is parallel to the insulating layer, and the vertex of the microlens is the point of contact between this tangent and the hemisphere. The vertex of the microlens can be determined in the same way in any cross-sectional view. In other words, among the tangents to the semicircle of the microlens in the cross-sectional view, there is a tangent that is parallel to the insulating layer, and the vertex of the microlens is the point of contact between this tangent and the semicircle.

[0164] It is also possible to define the midpoint of a microlens. In the cross section of the microlens, a line segment is imagined from the point where an arc shape ends to the point where another arc shape ends, and the midpoint of this line segment can be called the midpoint of the microlens. The cross section for determining the vertex and midpoint may be a cross section perpendicular to the insulating layer.

[0165] [Counter substrate] An opposing substrate may be provided on the planarization layer. The opposing substrate is called an opposing substrate because it is provided at a position corresponding to the aforementioned substrate. The constituent material of the opposing substrate may be the same as that of the aforementioned substrate. When the aforementioned substrate is defined as a first substrate, the opposing substrate may be a second substrate.

[0166] [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 controls the emission of the first light-emitting element and the second light-emitting element independently. The active matrix type circuit may be voltage-programmed or current-programmed. The drive circuit has a pixel circuit for each pixel. The pixel circuit may have a light-emitting element, a transistor that controls the emission brightness of the light-emitting element, a transistor that controls the emission timing, a capacitor that holds the gate voltage of the transistor that controls the emission brightness, and a transistor for connecting to GND without going through the light-emitting element.

[0167] 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 a transistor constituting the pixel circuit may be smaller than the mobility of a transistor constituting the display control circuit. The slope of the current-voltage characteristics of the transistor constituting the pixel circuit may be smaller than the slope of the current-voltage characteristics of the transistor constituting the display control circuit. The slope of the current-voltage characteristics can be measured by the so-called Vg-Ig characteristics. The transistor constituting the pixel circuit is a transistor connected to a light-emitting element, such as a first light-emitting element.

[0168] [Pixels] An organic light emitting device having an organic light emitting element may have a plurality of pixels, each of which has sub-pixels that emit different colors, for example, RGB colors.

[0169] A pixel emits light from an area called a pixel aperture. This area is the same as the first area. 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, more specifically, it may be 8 μm, 7.4 μm, or 6.4 μm.

[0170] The pixels may be arranged in a known manner in a plan view. For example, they may be in a stripe arrangement, a delta arrangement, a pentile arrangement, or a Bayer arrangement. The shape of the subpixels in a plan view may be any known shape. For example, they may be rectangular, quadrilaterals such as diamonds, or hexagons. Of course, a shape that is close to a rectangle, rather than an exact shape, is included in the rectangle. The shape of the subpixels and the pixel arrangement may be used in combination.

[0171] <Applications of organic light-emitting devices> The organic light-emitting device according to this embodiment can be used as a component of a display device or a lighting device, and can also be used as an exposure light source for an electrophotographic image forming device, a backlight for a liquid crystal display device, or a light-emitting device having a white light source and a color filter.

[0172] The display device may be an image information processing device that has an image input unit that inputs image information from an area CCD, a linear CCD, a memory card, etc., has 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, at least one of which may have the organic light-emitting element of this embodiment and a transistor connected to the organic light-emitting element.

[0173] The display unit of the imaging device or inkjet printer may have a touch panel function. The driving method of this touch panel function may be an infrared method, a capacitance method, a resistive film method, or an electromagnetic induction method, and is not particularly limited. The display device may also be used in the display unit of a multifunction printer.

[0174] Next, a display device according to this embodiment will be described with reference to the drawings. Fig. 2 is a 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).

[0175] FIG. 2(a) shows an example of a pixel, which is a component of the display device according to this embodiment. The pixel includes sub-pixels 10. The sub-pixels are divided into 10R, 10G, and 10B based on their light emission. The emitted colors may be distinguished by the wavelength of light emitted from the light-emitting layer, or the light emitted from the sub-pixels may be selectively transmitted or color-converted using a color filter or the like. Each sub-pixel 10 includes a reflective electrode serving as a first electrode 2 on an interlayer insulating layer 1, an insulating layer 3 covering the edge of the first electrode 2, an organic compound layer 4 covering the first electrode 2 and the insulating layer 3, a transparent electrode serving as a second electrode 5, a protective layer 6, and a color filter 7.

[0176] A transistor and a capacitor element may be disposed below or inside the interlayer insulating layer 1. The transistor and the first electrode 2 may be electrically connected via a contact hole or the like (not shown).

[0177] The insulating layer 3 is also called a bank or a pixel separation film. It covers the edges of the first electrode 2 and is disposed to surround the first electrode 2. The portion where the insulating layer 3 is not disposed contacts the organic compound layer 4 and becomes a light-emitting region.

[0178] 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 .

[0179] The second electrode 5 may be a transparent electrode, a reflective electrode, or a semi-transparent electrode.

[0180] The protective layer 6 reduces the penetration of moisture into the organic compound layer 4. Although the protective layer 6 is illustrated as being one layer, it may be multiple layers, and each layer may be an inorganic compound layer and an organic compound layer.

[0181] The color filters 7 are divided into 7R, 7G, and 7B depending on their colors. The color filters 7 may be formed on a planarization film (not shown). A resin protective layer (not shown) may be provided on the color filters 7. The color filters 7 may be formed on a protective layer 6. Alternatively, the color filters 7 may be provided on an opposing substrate such as a glass substrate and then bonded thereto.

[0182] The display device 100 in FIG. 2(b) has an organic light-emitting element 26 and a TFT 18 as an example of a transistor. A substrate 11 made of glass, silicon, or the like is provided with an insulating layer 12 on top of it. An active element such as the TFT 18 is disposed 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 disposed on top of it. The TFT 18 also includes a drain electrode 16 and a source electrode 17. An insulating film 19 is provided on top of the TFT 18. An anode 21 constituting the organic light-emitting element 26 and the source electrode 17 are connected via a contact hole 20 provided in the insulating film 19.

[0183] 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 embodiment shown in Fig. 2(b). In other words, it is sufficient that either the anode 21 or the cathode 23 is electrically connected to either the source electrode 17 or the drain electrode 16 of the TFT 18. TFT stands for thin film transistor.

[0184] 2(b), the organic compound layer 22 is illustrated as a single layer, but may be a multi-layer organic compound layer 22. A first protective layer 24 and a second protective layer 25 are provided on the cathode 23 to reduce deterioration of the organic light-emitting element 26.

[0185] In the display device 100 of FIG. 2(b), transistors are used as switching elements, but other switching elements may be used instead.

[0186] The transistors used in the display device 100 of Fig. 2(b) are not limited to transistors using single-crystal silicon wafers, but may also be thin-film transistors having an active layer on an insulating surface of a substrate. Examples of active layers include single-crystal silicon, amorphous silicon, microcrystalline silicon, and other non-single-crystal silicon, as well as non-single-crystal oxide semiconductors such as indium zinc oxide and indium gallium zinc oxide. Thin-film transistors are also called TFT elements.

[0187] The transistors included in the display device 100 of Fig. 2(b) may be formed within a substrate such as a Si substrate. Here, "formed within a substrate" means that the substrate itself, such as a Si substrate, is processed to form the transistors. In other words, having a transistor within a substrate can be seen as the substrate and the transistor being formed integrally.

[0188] The organic light-emitting element according to this embodiment has its emission brightness controlled by a TFT, which is an example of a switching element. By providing multiple organic light-emitting elements on a surface, an image can be displayed based on the emission brightness of each element. Note that the switching element according to this embodiment is not limited to a TFT, and may be a transistor formed from low-temperature polysilicon or an active matrix driver formed on a substrate such as a Si substrate. "On the substrate" can also be referred to as "inside the substrate." Whether to provide a transistor in the substrate or to use a TFT is determined by the size of the display unit. For example, for a display size of about 0.5 inches, it is preferable to provide the organic light-emitting element on a Si substrate.

[0189] 3 is a schematic diagram illustrating an example of a display device according to this embodiment. The display device 1000 may include 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. The touch panel 1003 and the display panel 1005 are connected by flexible printed circuits FPCs 1002 and 1004. Transistors are printed on the circuit board 1007. The battery 1008 may not be provided if the display device is not a portable device, and may be provided in a different position even if the display device is a portable device.

[0190] The display device according to this embodiment may have color filters having red, green, and blue colors, which may be arranged in a delta arrangement.

[0191] The display device according to the present embodiment may be used as a display unit of a mobile terminal. In this case, the display device may have both a display function and an operation function. Examples of the mobile terminal include a mobile phone such as a smartphone, a tablet, and a head-mounted display.

[0192] The display device according to this embodiment may be used as a display unit of an imaging device having an optical unit with a plurality of lenses and an imaging element that receives light that has passed through the optical unit. The imaging device may have a display unit that displays information acquired by the imaging element. The display unit may be a display unit exposed to the outside of the imaging device or a display unit disposed within a viewfinder. The imaging device may be a digital camera or a digital video camera.

[0193] 4A 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 include a display device according to this embodiment. In this case, the display device may display not only an image to be captured, but also environmental information, imaging instructions, and the like. The environmental information may include the intensity of external light, the direction of external light, the speed at which the subject is moving, the possibility that the subject will be blocked by an obstruction, and the like.

[0194] Since the optimum timing for capturing an image is very short, it is better to display information as soon as possible. Therefore, it is preferable to use a display device using the organic light-emitting element of this embodiment. This is because the organic light-emitting element has a fast response speed. A display device using the organic light-emitting element can be used more preferably than a liquid crystal display device, which requires a high display speed.

[0195] The imaging device 1100 has an optical section (not shown). The optical section has multiple lenses, which form an image on an imaging element housed in a housing 1104. The focus of the multiple lenses can be adjusted by adjusting their relative positions. This operation can also be performed automatically. The imaging device may also be called a photoelectric conversion device. Instead of sequentially capturing images, the photoelectric conversion device can include an imaging method that detects the difference from the previous image, or a method of cutting out an image from a constantly recorded image, etc.

[0196] FIG. 4(b) is a schematic diagram illustrating 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 reaction unit. The operation unit 1202 may be a biometric recognition unit that recognizes a fingerprint to perform unlocking or the like. 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. An image captured by the camera function is displayed on the display unit 1201. Examples of the electronic device 1200 include a smartphone and a laptop computer.

[0197] FIG. 5 is a schematic diagram illustrating an example of a display device according to this embodiment. FIG. 5(a) illustrates 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. The display device 1300 has the frame 1301 and a base 1303 that supports the display unit 1302. The base 1303 is not limited to the form shown in FIG. 5(a). The lower side of the frame 1301 may also serve as the base. 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.

[0198] FIG. 5(b) is a schematic diagram illustrating another example of a display device according to this embodiment. The display device 1310 in FIG. 5(b) is configured to be bendable, 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 include light-emitting elements according to this embodiment. The first display unit 1311 and the second display unit 1312 may be a single, seamless display unit. The first display unit 1311 and the second display unit 1312 can be separated by the 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 display a single image.

[0199] FIG. 6(a) is a schematic diagram illustrating an example of a lighting device according to this embodiment. The lighting device 1400 may include a housing 1401, a light source 1402, a circuit board 1403, an optical filter 1404 that transmits light emitted by the light source 1402, and a light diffusion unit 1405. The light source 1402 may include 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 light from the light source, such as for illumination, and deliver the light over a wide area. The optical filter 1404 and the light diffusion unit 1405 may be provided on the light emission side of the lighting. If necessary, a cover may be provided on the outermost surface.

[0200] The lighting device is, for example, a device that illuminates a room. The lighting device may emit white, daylight white, or any other color from blue to red. It may have a dimming circuit that dims these colors. 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. Furthermore, white has a color temperature of 4200K, and daylight white has a color temperature of 5000K. The lighting device may have a color filter.

[0201] The lighting device according to this embodiment may also include a heat dissipation unit, which dissipates heat from within the device to the outside, and may be made of a material such as a metal with a high specific heat capacity or liquid silicon.

[0202] 6(b) is a schematic diagram of an automobile, which is an example of a moving body according to this embodiment. The automobile has tail lamps, which are an example of lighting fixtures. The automobile 1500 has tail lamps 1501, and may be configured to turn on the tail lamps when braking or the like is performed.

[0203] The tail lamp 1501 may include an organic light-emitting element according to this embodiment. The tail lamp 1501 may include a protective member for protecting the organic light-emitting element. The protective member may be made of any material as long as it has a certain degree of strength and is transparent, but is preferably made of polycarbonate or the like. Polycarbonate may be mixed with a furandicarboxylic acid derivative, an acrylonitrile derivative, or the like.

[0204] The automobile 1500 may have a 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 automobile. The transparent display may have an organic light-emitting element according to this embodiment. In this case, the constituent materials of the electrodes and the like of the organic light-emitting element are made of transparent materials.

[0205] The moving body according to this embodiment may be a ship, an aircraft, a drone, or the like. The moving body may have a body and a lighting device provided on the body. The lighting device may emit light to indicate the position of the body. The lighting device has the organic light-emitting element according to this embodiment.

[0206] An application example of the display device of each of the above-described embodiments will be described with reference to Fig. 7. The display device can be applied to a system that can be attached as a wearable device, such as smart glasses, an HMD, or a smart contact lens. The image capturing and display device used in such an application example includes an image capturing device capable of photoelectrically converting visible light and a display device capable of emitting visible light.

[0207] Fig. 7(a) is a schematic diagram showing an example of a wearable device according to an embodiment of the present invention. Using Fig. 7(a), glasses 1600 (smart glasses) according to one application example will be described. An imaging device 1602 such as a CMOS sensor or SPAD is provided on the front side of a lens 1601 of the glasses 1600. In addition, a display device according to each of the above-mentioned embodiments is provided on the back side of the lens 1601.

[0208] The glasses 1600 further include a control device 1603. The control device 1603 functions as a power source that supplies power to the image capture device 1602 and the display device. The control device 1603 also controls the operations of the image capture device 1602 and the display device. The lens 1601 is formed with an optical system for focusing light onto the image capture device 1602.

[0209] FIG. 7(b) is a schematic diagram showing another example of a wearable device according to an embodiment of the present invention. Using FIG. 7(b), glasses 1610 (smart glasses) according to one application example will be described. The glasses 1610 have a control device 1612, which is equipped with an imaging device corresponding to the imaging device 1602 in FIG. 7(a) and a display device. A lens 1611 is formed with an optical system for projecting light emitted from the imaging device in the control device 1612 and the display device, and an image is projected onto the lens 1611. The control device 1612 functions as a power source that supplies power to the imaging device and the display device, and also controls the operation of the imaging device and the display device.

[0210] The control device 1612 may include a gaze detection unit that detects the wearer's gaze. The gaze detection may use infrared light. The infrared light emitter emits infrared light toward the eyeball of the user gazing at the display image. An imaging unit with a light-receiving element detects the reflected infrared light from the eyeball, thereby obtaining a captured image of the eyeball. A reduction unit that reduces light from the infrared light emitter to the display unit in a planar view reduces degradation of image quality. The user's gaze toward the displayed image is detected from the captured image of the eyeball obtained by capturing infrared light. Any known method can be applied to gaze detection using the captured image of the eyeball. As an example, a gaze detection method based on a Purkinje image formed by reflection of irradiated light on the cornea can be used. More specifically, gaze detection processing based on the pupil-corneal reflex method is performed. Using the pupil-corneal reflex method, a gaze vector representing the orientation (rotation angle) of the eyeball is calculated based on the image of the pupil and the Purkinje image included in the captured image of the eyeball, thereby detecting the user's gaze.

[0211] A display device according to one embodiment of the present invention may include an imaging device having a light receiving element, and may control the display image of the display device based on user line-of-sight information from the imaging device. Specifically, the display device determines a first field of view area where the user gazes and a second field of view area other than the first field of view area based on the line-of-sight information. The first field of view area and the second field of view area may be determined by a control device of the display device, or may be determined by an external control device and received. 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.

[0212] The display area includes a first display area and a second display area different from the first display area, and a high-priority area is determined from the first display area and the second display area based on line-of-sight information. The first field of view area and the second field of view area may be determined by a control device of the display device, or 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 areas other than the high-priority area. In other words, the resolution of an area with a relatively low priority may be lowered.

[0213] Note that AI may be used to determine the first field of view area and areas with high priority. The AI ​​may be a model configured to estimate the angle of gaze and the distance to an object in the line of sight from an image of the eyeball, using as training data an image of the eyeball and the direction in which the eyeball in the image was actually looking. The AI ​​program may be included in the display device, the imaging device, or an external device. If included in an external device, it is transmitted to the display device via communication.

[0214] When display control is performed based on visual recognition detection, the smart glasses can be preferably applied to smart glasses that further include an imaging device for capturing images of the outside world. The smart glasses can display captured external information in real time.

[0215] 8(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 photoconductor 27, an exposure light source 28, a charging unit 30, a developing unit 31, a transfer unit 32, a transport roller 33, and a fixing unit 35. Light 29 is irradiated from the exposure light source 28, and an electrostatic latent image is formed on the surface of the photoconductor 27. The exposure light source 28 includes the organic light-emitting element according to this embodiment. The developing unit 31 includes toner and the like. The charging unit 30 charges the photoconductor 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 fixing unit 35 fixes the image formed on the recording medium 34.

[0216] 8(b) and 8(c) are diagrams showing an exposure light source 28 and are schematic diagrams illustrating a state in which multiple light-emitting units 36 are arranged on a long substrate. Arrow 37 indicates the direction parallel to the axis of the photoconductor, the column direction in which the organic light-emitting elements are arranged. This column direction is the same as the axis direction about which the photoconductor 27 rotates. This direction can also be referred to as the long axis direction of the photoconductor 27. FIG. 8(b) shows a configuration in which the light-emitting units 36 are arranged along the long axis direction of the photoconductor 27. FIG. 8(c) shows a configuration different from FIG. 8(b), in which the light-emitting units 36 are arranged alternately in the column direction in the first and second columns. The first and second columns are arranged at different positions in the row direction. In the first column, multiple light-emitting units 36 are arranged at intervals. 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. In other words, multiple light-emitting units 36 are also arranged at intervals in the row direction. The arrangement in FIG. 8(c) can also be described as a grid arrangement, a houndstooth arrangement, or a checkerboard pattern.

[0217] As described above, by using a device using the organic light-emitting element according to this embodiment, it is possible to provide a stable display with good image quality even over a long period of time. [Example]

[0218] The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[0219] [Example 1 (Synthesis of Exemplary Compound F-1)] (Reference example) Exemplary compound F-1 was synthesized according to the following scheme.

[0220] [ka] (1) Synthesis of compound f-3 The following reagents and solvents were placed in a 200 ml recovery flask. Compound f-1: 6.08g (20.0mmol) Compound f-2: 2.27g (20.0mmol) Sodium carbonate: 5.3 g (50.0 mmol) Pd(PPh3)4: 578 mg Toluene: 35 ml Water: 35ml Ethanol: 10ml Next, the reaction solution was heated and stirred at 60°C for 5 hours under a nitrogen stream. After the reaction was completed, the mixture was extracted with toluene, and the organic layer was concentrated to dryness. The resulting solid was purified by silica gel column chromatography (toluene:ethyl acetate mixture) to obtain 3.0 g of a transparent solid (f-3) (yield: 58%).

[0221] (2) Synthesis of compound f-5 The following reagents and solvents were placed in a 50 ml recovery 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 for 5 hours under a nitrogen stream. After the reaction was completed, the reaction solution was filtered, and the obtained solid was washed on the filter with water and methanol. 3.4 g of a yellow solid (f-5) was obtained (yield: 63%).

[0222] (3) Synthesis of compound f-6 The following reagents and solvents were placed in a 100 ml recovery flask. Compound f-5: 1.07g (1.00mmol) Silver triflate: 0.514 g (2.00 mmol) Methylene chloride: 30 ml Methanol: 1.3 ml Next, the reaction solution was heated and stirred at room temperature for 7 hours under a nitrogen stream. After the reaction was completed, the solvent was distilled off from the reaction solution at 40° C., and 1.56 g of a yellowish brown solid (f-6) was obtained.

[0223] (4) Synthesis of Example Compound F-1 The following reagents and solvents were placed in a 100 ml recovery 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 for 5 hours under a nitrogen stream. After the reaction was completed, the reaction solution was filtered, and the obtained solid was washed on the filter with water and methanol. The obtained solid was purified by silica gel column chromatography (toluene:ethyl acetate mixture) to obtain 0.17 g (yield: 23%) of a yellow solid (exemplified compound F-1).

[0224] Exemplary Compound F-1 was subjected to mass spectrometry using MALDI-TOF-MS (Autoflex LRF, manufactured by Bruker).

[0225] [MALDI-TOF-MS] Measured value: m / z=771 Calculated value: C 42 H 32 IrN3=771

[0226] [Comparative Example 1] In Example 1, "(1) Synthesis of compound f-3," we attempted to synthesize g-2 in the same manner, except that raw material f-2 was replaced with raw material g-1 shown in the following scheme. However, the target compound g-2 was not obtained. This is thought to be due to the steric hindrance between the phenyl group of the pyridine ring and the methyl group of the fluorene ring.

[0227] [ka]

[0228] [Examples 2 to 20 (Synthesis of Exemplary Compounds)] (Examples 2, 4, 10, and 17 are reference examples) As shown in Tables 3 to 5, the exemplary compounds shown in Examples 2 to 20 were synthesized in the same manner as in Example 1, except that raw material f-1 in Example 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 actual measured values ​​(m / z) of the mass spectrometry results measured in the same manner as in Example 1 are also shown.

[0229] [Table 3]

[0230] [Table 4]

[0231] [Table 5]

[0232] [Example 21 (Synthesis of Exemplary Compound D-11)] (Reference example) Exemplary compound D-11 was synthesized according to the following scheme. [ka]

[0233] (1) Synthesis of compound f-7 The following reagents and solvents were placed in a 100 ml recovery flask. Compound f-3: 5.42g (20.0mmol) Iridium chloride hydrate: 1.60g Ethoxyethanol: 45ml Water: 15ml Next, the reaction solution was heated and stirred at 130°C for 5 hours under a nitrogen stream. After the reaction was completed, the reaction solution was filtered, and the obtained solid was washed on the filter with water and methanol. 3.8 g of a yellow solid (f-7) was obtained (yield: 49%).

[0234] (2) Synthesis of Example Compound D-11 The following reagents and solvents were placed in a 100 ml recovery flask. Compound f-7: 1.54g (1.00mmol) Compound f-8: 0.40g (4.00mmol) Sodium carbonate: 1.06 g (10.0 mmol) Ethoxyethanol: 30ml Water: 12ml Next, the reaction solution was heated and stirred at 100°C for 6 hours under a nitrogen stream. After cooling, methanol was added, and the mixture was filtered and washed with methanol to obtain 0.37g of a yellow solid (D-11) (yield: 45%).

[0235] Mass spectrometry was carried out on Exemplary Compound D-11 in the same manner as in Example 1.

[0236] [MALDI-TOF-MS] Measured value: m / z=832 Calculated value: C 45 H 39 IrO2N3=832

[0237] [Examples 22 to 26 (Synthesis of Exemplary Compounds)] (Example 26 is a reference example) As shown in Table 6, the exemplary compounds shown in Examples 22 to 26 were synthesized in the same manner as in Example 21, except that raw material f-3 in Example 21 was replaced with raw material 1 and raw material f-8 with raw material 2. The actual measured values ​​(m / z) of the mass spectrometry results measured in the same manner as in Example 21 are also shown.

[0238] [Table 6]

[0239] Example 27 (Synthesis of Exemplary Compound H-1) (Reference example) Exemplary compound H-1 was synthesized according to the following scheme. [ka]

[0240] The following reagents and solvents were placed in a 100 ml recovery flask. Compound D-11: 0.83g (1.00mmol) Compound f-3: 0.68g (2.50mmol) Sodium carbonate: 1.06 g (10.0 mmol) Glycerol: 30ml 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 resulting solid was purified by silica gel column chromatography (toluene:ethyl acetate mixture) to obtain 0.17 g (yield: 17%) of a yellow solid (exemplified compound H-1).

[0241] Mass spectrometry was carried out on Exemplary Compound H-1 in the same manner as in Example 1.

[0242] [MALDI-TOF-MS] Measured value: m / z=1003 Calculated value: C 60 H 40 IrN3=1003

[0243] [Examples 28 to 29 (Synthesis of Exemplary Compounds)] (Example 29 is a reference example) As shown in Table 5, the exemplary compounds shown in Examples 28 and 29 were synthesized in the same manner as in Example 27, except that raw material D-11 in Example 27 was replaced with raw material 1 and raw material f-3 with raw material 2. The actual measured values ​​(m / z) of the mass spectrometry results measured in the same manner as in Example 27 are also shown.

[0244] [Table 7]

[0245] [Example 30] (Reference example) An organic light-emitting device with a bottom emission structure was fabricated by sequentially forming 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 on a substrate.

[0246] First, an ITO film was formed on a glass substrate and then patterned as desired to form an ITO electrode (anode). At this time, the film thickness of the ITO electrode was set to 100 nm. The substrate on which the ITO electrode was formed was used as the ITO substrate in the following process. Next, a 1.3 × 10 -4 Vacuum deposition was performed by resistance heating in a vacuum chamber at 100 Pa to successively form the organic compound layer and electrode layer shown in Table 8 on the ITO substrate. At this time, the electrode area of ​​the opposing electrode (metal electrode layer, cathode) was 3 mm 2 It was made to be like this.

[0247] [Table 8]

[0248] The characteristics of the obtained device were measured and evaluated. The efficiency of the light-emitting device was 61 cd / A. Furthermore, at a current density of 50 mA / cm 2 A continuous driving test was performed at 1000 rpm, and the time when the luminance degradation rate reached 5% was measured. In Examples 31 to 37 and Comparative Examples 2 to 5, the time when the luminance degradation rate reached 5% is shown as a ratio when the time in these Examples is set to 1.0.

[0249] In this example, the measuring device was specifically a microcurrent meter 4140B manufactured by Hewlett-Packard Company to measure the current-voltage characteristics, and a BM7 manufactured by Topcon Corporation to measure the luminance.

[0250] [Examples 31 to 37, Comparative Examples 2 to 5] (Examples 33 and 36 are reference examples) An organic light-emitting device was produced in the same manner as in Example 30, except that the materials were appropriately changed to those shown in Table 9. Compound Q-2-1, Compound T-1, and Compound T-2 were the following compounds.

[0251] [ka]

[0252] The obtained element was evaluated in the same manner as in Example 30. The time when the luminance degradation rate reached 5% is shown as a ratio when the time in Example 30 is set to 1.0. The measurement results are shown in Table 9.

[0253] [Table 9]

[0254] Table 9 shows that the light-emitting elements of the examples have high-efficiency light emission and little deterioration in brightness. In the light-emitting elements of Comparative Examples 2 and 3, the light-emitting dopant has a cyano group or a pyridyl group in the pyridylfluorene ligand, which results in high polarity of the ligand, and weak interaction with the hydrocarbon host material, resulting in poor light-emitting efficiency and significant deterioration in brightness. In the light-emitting elements of Comparative Examples 4 and 5, the host material contains highly polar atoms such as nitrogen atoms and oxygen atoms, which results in weak interaction with the compound represented by general formula [1] of this embodiment, resulting in low light-emitting efficiency and significant deterioration in brightness, partly due to the poor stability of the host material.

[0255] As described above, by using the compound represented by the general formula [1] according to this embodiment as an emitting dopant and selecting a preferable host material, it is possible to provide a device having high efficiency and excellent durability characteristics.

[0256] [Example 38] An organic light-emitting device was produced in the same manner as in Example 30, except that the compounds and film thicknesses were changed as shown in Table 10.

[0257] [Table 10]

[0258] The obtained device was evaluated in the same manner as in Example 30. The efficiency of the light-emitting device was 63 cd / A. In Examples 39 to 43 and Comparative Examples 6 to 8, the time at which the luminance degradation rate reached 5% is shown as a ratio when the time in these examples is set to 1.0.

[0259] [Examples 39 to 43, Comparative Examples 6 to 8] (Examples 40 and 43 are reference examples) An organic light-emitting device was produced in the same manner as in Example 38, except that the materials were appropriately changed to those shown in Table 11. Compounds Q-2-1, Q-2-2 and S-4-1 are the following compounds.

[0260] [ka]

[0261] The obtained element was evaluated in the same manner as in Example 38. The time when the luminance degradation rate reached 5% is shown as a ratio, assuming that the time when the luminance degradation rate in Example 38 reached 5% was 1.0. The measurement results are shown in Table 11.

[0262] [Table 11]

[0263] Table 11 shows that the light-emitting elements of the examples have high light emission efficiency and little deterioration in brightness. In the light-emitting elements of Comparative Examples 6 to 8, the host material contains highly polar atoms such as nitrogen atoms and sulfur atoms, which results in weak interaction with the compound represented by general formula [1] of this embodiment, resulting in low light emission efficiency and significant brightness deterioration due in part to poor stability of the host material. Furthermore, Comparative Examples 7 and 8 have even poorer light emission efficiency. Since the assist material contains a triazine skeleton, it is believed to form an exciplex with the compound represented by general formula [1] of this embodiment.

[0264] As described above, by using the compound represented by the general formula [1] according to this embodiment as an emitting dopant and selecting a preferable host material, it is possible to provide a device having high efficiency and excellent durability characteristics. [Explanation of symbols]

[0265] 1: interlayer insulating layer, 2: first electrode, 3: insulating layer, 4: organic compound layer, 5: second electrode, 6: protective layer, 7: color filter, 10: subpixel, 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. At least an anode, a light-emitting layer, and a cathode are provided in this order; the light-emitting layer contains at least a dopant material and a host material; The dopant material is a compound represented by the following general formula [1]: The organic light-emitting device is characterized in that the host material is a hydrocarbon. 【Chemistry 1】 In formula [1], R 1 ~R 8 are each independently selected from a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted silyl group, and a substituted or unsubstituted aryl group. 1 ~R 8 does not contain a cyano group. m represents an integer of 1 or more and 3 or less, and n represents an integer of 0 or more and 2 or less, provided that m+n is 3. X represents a bidentate ligand, and the partial structure IrX is any of the structures represented by the following general formulas [2] and [3]. 【Chemistry 2】 In formulas [2] and [3], R 9 ~R 19 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 alkoxy group, a substituted or unsubstituted silyl group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group. 16 ~R 19 may be bonded to each other to form a ring. Ring A is any of the structures represented by the following general formulas [4] to [7]. 【Transformation 3】 In formulas [4] to [7], R 20 ~R 29 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 alkoxy group, a substituted or unsubstituted silyl group, and a substituted or unsubstituted aryl group. However, at least one of R 9 to R 29 is a tertiary alkyl group.

2. The organic compound according to claim 1, wherein R 1 to R 8 are not a tertiary alkyl group.

3. The R 1 ~R 8 2. The organic light-emitting device according to claim 1, wherein at least one of the groups is a tertiary alkyl group.

4. The organic light-emitting device according to claim 3 , wherein the tertiary alkyl group is a tertiary butyl group.

5. 5. The organic light-emitting device according to claim 1, wherein the ring A has a structure represented by the general formula [4].

6. The R 20 The organic light-emitting device according to claim 5 , wherein is a tertiary butyl group.

7. The partial structure IrX is a structure represented by the general formula [3], and the R 12 ~R 19 and are each independently selected from the group consisting of a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group, and a substituted or unsubstituted silyl group.

8. The R 9 ~R 11 or at least one of the R 12 ~R 19 8. The organic light-emitting device according to claim 1, wherein at least one of the groups is a tertiary alkyl group.

9. The organic light-emitting device according to claim 8 , wherein the tertiary alkyl group is a tertiary butyl group.

10. 10. The organic light-emitting element according to claim 1, wherein the host material has at least one of fluoranthene, benzo[e]pyrene, benzo[g]chrysene, benzo[c]chrysene, coronene, benzofluorene, chrysene, picene, naphthalene, phenanthrene, triphenylene, and fluorene in a skeleton.

11. 11. The organic light-emitting element according to claim 1, wherein the host material has at least one of a chrysene ring, a picene ring, a phenanthrene ring, a triphenylene ring, and a fluoranthene ring in its skeleton.

12. The host material is an SP 3 12. The organic light-emitting device according to claim 1, which does not contain carbon.

13. The organic light-emitting device according to claim 1 , wherein the light-emitting layer contains an assist material.

14. The organic light-emitting device according to claim 13 , wherein the assist material is a compound partially having any one of the following structures: 【Chemistry 4】 (In the above structure, X' represents an oxygen atom, a sulfur atom, or a substituted or unsubstituted carbon atom.)

15. A display device comprising a plurality of pixels, at least one of the plurality of pixels comprising the organic light-emitting element according to claim 1 and a transistor connected to the organic light-emitting element.

16. an optical unit having a plurality of lenses, an image pickup element that receives light that has passed through the optical unit, and a display unit that displays an image picked up by the image pickup element; The photoelectric conversion device, wherein the display section comprises the organic light-emitting element according to claim 1 .

17. 15. An electronic device comprising: a display unit having the organic light-emitting element according to claim 1; a housing in which the display unit is provided; and a communication unit provided in the housing and communicating with an external device.

18. 15. A lighting device comprising: a light source having the organic light-emitting element according to claim 1; and a light diffusion section or an optical filter that transmits light emitted by the light source.

19. A moving body comprising: a lamp having the organic light-emitting element according to claim 1; and a vehicle on which the lamp is provided.

20. An exposure light source for an electrophotographic image forming apparatus, comprising the organic light-emitting element according to claim 1 .

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