Luminescent composition, organic light emitting element, display device, imaging device, electronic device, lighting device, moving body, and method for manufacturing organic light emitting element

Abstract

To provide a luminescent composition that can improve the luminescence quantum yield of dopant luminescence and reduce host luminescence.SOLUTION: A luminescent composition includes a specific organometallic complex, a specific fluorene oligomer, and a polymeric host material.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a luminescent composition, an organic light-emitting element, a display device, an imaging device, an electronic device, an illumination device, a mobile device, and a method for manufacturing an organic light-emitting element. [Background technology]

[0002] An organic light-emitting device (organic LED) is an electronic element having a pair of electrodes, a first electrode and a second electrode, and an organic compound layer placed between these electrodes. By injecting electrons and holes from the pair of electrodes into the organic compound layer, the light-emitting organic compound in the organic compound layer is activated from the ground state to an excited state, and the excess energy released when it returns from the excited state to the ground state is emitted as light. Organic light-emitting devices are also called organic electroluminescent devices or organic EL devices.

[0003] Luminescent organic compounds are broadly classified into fluorescent materials and phosphorescent materials based on their luminescence principle. In the electrical exciton generation within organic light-emitting devices, according to quantum mechanical principles, 25% are singlet energy and 75% are triplet energy. Therefore, phosphorescent materials that emit light from a triplet excited state are known to exhibit higher luminescence efficiency than fluorescent materials that emit light from a singlet excited state. For example, Ir(piq)3 [tris[1-phenylisoquinoline-C2,N]iridium(III)], an organometallic complex with the following structure, is known as a red phosphorescent material.

[0004] [ka]

[0005] Conventionally, organic light-emitting devices have been manufactured by a so-called vapor deposition method in which materials for forming various functional layers such as organic compound layers, inorganic compound layers, and electrodes are thermally evaporated onto a substrate under high vacuum. However, in the vapor deposition method, it is difficult to achieve uniform vapor deposition on a large-area substrate, and there are also problems with material utilization rate, manufacturing cost, and the like.

[0006] In recent years, a printing method has been considered as a method for manufacturing an organic light-emitting device that can solve the above problems in the vapor deposition method. In the printing method, an organic light-emitting device is manufactured by applying a liquid composition containing various materials to a substrate. Since it is necessary to apply the liquid composition to the substrate and form a uniform film, the use of a polymer material or an oligomer having excellent film-forming properties and film stability as a host material has been considered.

[0007] Non-Patent Documents 1 and 2 describe the manufacture of an element by a printing method using a composition containing a polymer material and an Ir complex. Patent Document 1 describes a composition containing a fluorene oligomer and an Ir complex. Patent Document 2 describes a composition in which an oligomer and a polymer material are used in combination as a host material.

[0008] From the viewpoints of high efficiency and long life of the organic light-emitting device, it is important that the energy of excitons generated by the recombination of electrons and holes quickly moves to the light-emitting material. A phosphorescent material as a light-emitting material can efficiently utilize triplet energy. However, in this case, in order to utilize singlet energy, it is necessary to go through singlet energy transfer from the host to the dopant and intersystem crossing from singlet to triplet. If singlet energy transfer and intersystem crossing do not occur quickly, singlet energy is lost as non-radiative deactivation or the emission of the host itself. Many of the polymer materials and oligomers used in the printing method have luminescence properties. Therefore, when host emission occurs as an energy deactivation pathway, not only does the dopant emission decrease, but color purity also decreases due to the mixing of emission of a hue different from the desired hue from the host.

Prior Art Documents

Patent Documents

[0009] [Patent Document 1] International Publication No. 2017 / 038613 [Patent Document 2] Japanese Patent Publication No. 2009-071222 [Non-patent literature]

[0010] [Non-Patent Document 1] Thin Solid Films,2006,499,359-363 [Non-Patent Document 2] J.Mater.Chem.,2012,22,4660-4668 [Overview of the project] [Problems that the invention aims to solve]

[0011] The present inventors investigated various properties of the compositions described in Patent Documents 1 and 2. As a result, they found that host emission occurred, resulting in insufficient emission quantum yield of dopant emission.

[0012] Therefore, an object of the present invention is to provide a luminescent composition that can improve the luminescence quantum yield of dopant emission and reduce host emission. Another object of the present invention is to provide an organic light-emitting device, display device, imaging device, electronic device, lighting device, and mobile device having a light-emitting layer formed by the luminescent composition. Furthermore, another object of the present invention is to provide a method for manufacturing an organic light-emitting device using the luminescent composition. [Means for solving the problem]

[0013] The above objective is achieved by the present invention as described below. That is, the luminescent composition according to the present invention is a luminescent composition containing an organometallic complex, a fluorene oligomer, and a polymer host material, wherein the organometallic complex is at least one compound selected from the group consisting of compounds represented by the following general formula (1) and compounds represented by the following general formula (2), and the fluorene oligomer contains a unit represented by the following general formula (6), and the number of repeating units represented by the general formula (6) is 6 or more and 14 or less.

[0014] [ka]

[0015] (In general formulas (1) and (2), R 1 ~R 18 Each of these independently represents a hydrogen atom, a deuterium atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an aryl group, a heteroaryl group, an aryloxy group, a heteroaryloxy group, a silyl group, an alkoxycarbonyl group, an acyl group, or a cyano group. Ring A represents an aryl ring or a heteroaryl ring. L 1 -L 2 This is a bidentate ligand represented by any of the following general formulas (3) to (5).

[0016] [ka]

[0017] (In general formulas (3) to (5), R 19 ~R 33 Each of these independently represents a hydrogen atom, a deuterium atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an aryl group, or a heteroaryl group.

[0018] [ka]

[0019] (In general formula (6), R 101 and R 102 each independently represent a hydrogen atom, a deuterium atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an aryloxy group, or a heteroaryloxy group. A plurality of units represented by the general formula (6) are R 103 to R 106 any one of and R 107 to R 110 are bonded to each other by any one of. R 103 to R 110 not bonded to the molecular units of adjacent general formula (6) each independently represent a hydrogen atom, a deuterium atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an aryl group, a heteroaryl group, an aryloxy group, a heteroaryloxy group, or an amino group.) [Advantages of the Invention]

[0020] According to the present invention, it is possible to provide a light-emitting composition that improves the luminescence quantum yield of dopant emission and reduces the luminescence of the host. Further, according to another aspect of the present invention, it is possible to provide an organic light-emitting device, a display device, an imaging device, an electronic device, a lighting device, and a moving body having a light-emitting layer formed of the light-emitting composition. Furthermore, according to another aspect of the present invention, it is possible to provide a method for manufacturing an organic light-emitting device using the light-emitting composition. [Brief Description of the Drawings]

[0021] [Figure 1] (a) It is a schematic cross-sectional view showing an example of a pixel of a display device according to an embodiment of the present invention. (b) It is a schematic cross-sectional view of an example of a display device using an organic light-emitting device according to an embodiment of the present invention. [Figure 2] It is a schematic diagram of an example of a display device using an organic light-emitting device according to an embodiment of the present invention. [Figure 3] (a) It is a schematic diagram showing an example of an imaging device according to an embodiment of the present invention. (b) It is a schematic diagram showing an example of a portable device according to an embodiment of the present invention. [Figure 4] (a) A schematic diagram showing an example of a display device according to one embodiment of the present invention. (b) A schematic diagram showing an example of a foldable display device. [Figure 5] (a) A schematic diagram showing an example of a lighting device according to one embodiment of the present invention. (b) A schematic diagram showing an automobile, which is an example of a mobile body according to one embodiment of the present invention. [Figure 6] (a) A schematic diagram showing an example of a wearable device according to one embodiment of the present invention. (b) A schematic diagram showing an example of a wearable device according to one embodiment of the present invention, which includes an imaging device. [Modes for carrying out the invention]

[0022] The present invention will be further described in detail below with reference to preferred embodiments. It will be readily apparent to those skilled in the art that the present invention is not limited to the following description, and that its form and details can be modified in various ways without departing from the spirit and scope of the invention. That is, the present invention should not be interpreted as being limited by the following description. Unless otherwise specified, the physical properties are values ​​at room temperature (25°C). The luminescent composition of the present invention may be a composition that emits light itself, or a component formed by the composition that emits light; the term "luminescent composition" encompasses both of these.

[0023] The inventors investigated how to improve the quantum emission yield of dopant emission and reduce host emission by incorporating materials into a luminescent composition. As a result, they found that the above effects can be obtained with a luminescent composition containing a specific organometallic complex, a specific fluorene oligomer, and a polymeric host material. The organometallic complex is at least one compound selected from the group consisting of compounds represented by general formula (1) and compounds represented by general formula (2), which will be described later. The fluorene oligomer is a compound that contains a unit represented by general formula (6), and the number of repeating units is between 6 and 14. The inventors hypothesize the following mechanism by which the luminescent composition of the present invention can suppress host emission while improving the quantum emission yield of dopant emission.

[0024] The compounds represented by general formula (1) and general formula (2), which are organometallic complexes, are iridium complexes having benzoisoquinoline compounds as ligands and are red dopants. Examples of polymer host materials corresponding to these red dopants include polycarbazole-based and polyfluorene-based polymer compounds, which are commonly used as host materials for organic LEDs.

[0025] However, there is a large difference in S1 energy between polyvinylcarbazole compounds and the above-mentioned organometallic complex (red dopant). S1 energy represents the energy in the excited singlet state (S1). Therefore, energy transfer from the host to the dopant is less likely to occur, which can lead to a decrease in the emission quantum yield of the dopant. On the other hand, the difference in S1 energy between polyfluorene compounds and the above-mentioned organometallic complex (red dopant) is smaller than that of polyvinylcarbazole compounds. Therefore, energy transfer from the host to the dopant is more likely to occur. On the other hand, polyfluorene compounds have a rigid molecular structure and are prone to aggregation. As a result, trapping sites are formed, and the polyfluorene compound (host) itself emits blue light, reducing the color purity of the red emission of the red dopant.

[0026] In this invention, a compound (fluorene oligomer) containing a unit represented by general formula (6) is used. This improves the emission quantum yield of dopant emission and suppresses host emission. This is thought to be because the compound (fluorene oligomer) containing the unit represented by general formula (6) assists in energy transfer from the polymer host material with a higher S1 energy to the organometallic complex (dopant).

[0027] However, compounds containing the unit represented by general formula (6) are themselves rigid, similar to the polyfluorene compounds described above. The fluorene oligomers used in this invention have a repeating number of units represented by general formula (6) of 6 to 14, and the molecules are of a moderately compact size, which is thought to suppress aggregation of the polymer host material and make it difficult for trap sites to form. In this specification, the repeating number of units represented by general formula (6) in the fluorene oligomer can be rephrased as the number of carbazole skeletons, which are structures in which one benzene ring is condensed at the 2,3-position and 4,5-position of pyrrole. However, if multiple carbazole skeletons share one benzene ring, the condensed carbazole skeletons are counted together as one repeating unit. For example, the repeating number of compound 116, described later, is 7. If the repeating number is less than 6, trap sites are less likely to form, but it is not possible to assist in energy transfer from the polymer host material to the dopant. As a result, the emission quantum yield of dopant emission cannot be improved, and the emission of the host cannot be suppressed. On the other hand, if the number of repeats exceeds 14, the molecular size becomes large and rigid, similar to polyfluorene compounds, making it difficult to suppress aggregation of the polymer host material and resulting in the formation of trap sites. As a result, the emission quantum yield of dopant emission cannot be improved, and the emission of the host cannot be suppressed either.

[0028] <Luminescent composition> The luminescent composition of the present invention contains a specific organometallic complex, a fluorene oligomer, and a polymeric host material. The components and physical properties of the luminescent composition of the present invention will be described in detail below.

[0029] (Organometallic complexes) The luminescent composition contains an organometallic complex. The organometallic complex is at least one compound selected from the group consisting of compounds represented by general formula (1) and compounds represented by general formula (2).

[0030] [ka]

[0031] (In general formulas (1) and (2), R 1 ~R 18 Each of these independently represents a hydrogen atom, a deuterium atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an aryl group, a heteroaryl group, an aryloxy group, a heteroaryloxy group, a silyl group, an alkoxycarbonyl group, an acyl group, or a cyano group. Ring A represents an aryl ring or a heteroaryl ring. L 1 -L 2 (This is a bidentate ligand represented by at least one of the following general formulas (3) to (5).)

[0032] [ka]

[0033] (In general formulas (3) to (5), R 19 ~R 33 Each of these independently represents a hydrogen atom, a deuterium atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an aryl group, or a heteroaryl group.

[0034] In general formulas (1) to (5), the arrows indicate that an atom is coordinating with a metal atom.

[0035] In general formulas (1) and (2), R 1 ~R 18Each of these independently represents a hydrogen atom, a deuterium atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an aryl group, a heteroaryl group, an aryloxy group, a heteroaryloxy group, a silyl group, an alkoxycarbonyl group, an acyl group, or a cyano group.

[0036] Examples of halogen atoms include fluorine, chlorine, bromine, and iodine. Of these, fluorine is preferred from the viewpoint of thermal stability.

[0037] Examples of alkyl groups include linear or branched alkyl groups having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms. Specific examples of alkyl groups include methyl, ethyl, n-propyl, i-propyl, n-butyl, tert-butyl, sec-butyl, and octyl groups. Alkyl groups may be substituted with halogen atoms (such as those exemplified above), cyano groups, or nitro groups. Furthermore, one or more non-adjacent methylene groups of an alkyl group may be interrupted or substituted with -O-, -S-, -C(=O)-, -C(=O)O-, -O(C=O)-, -CH=CH-, or -C≡C-.

[0038] Examples of cycloalkyl groups include those having 3 to 30 carbon atoms, preferably 3 to 20 carbon atoms. Specific examples of cycloalkyl groups include cyclopropyl, cyclohexyl, 1-adamantyl, and 2-adamantyl groups. Cycloalkyl groups may be substituted with halogen atoms, cyano groups, or nitro groups.

[0039] Examples of alkoxy groups include alkoxy groups having 1 to 20 carbon atoms. Specifically, examples of alkoxy groups include methoxy groups, ethoxy groups, propoxy groups, and 2-ethyl-octyloxy groups. The alkoxy group may be substituted with a halogen atom, a cyano group, a nitro group, or an aryl group having 6 to 30 carbon atoms. Examples of halogen atoms include R in general formulas (1) and (2). 1 ~R 18Examples include those similar to those described as halogen atoms.

[0040] Examples of aryl groups include aryl groups having 6 to 30 carbon atoms, and may be monocyclic or fused rings. Specific examples of aryl groups include phenyl, naphthyl, biphenyl, fluorenyl, phenanthrenyl, anthracenyl, carbazolyl, dibenzofuryl, and dibenzothienyl groups. The aryl group may further be substituted with a halogen atom, a cyano group, an alkyl group, or an alkoxy group. Examples of halogen atoms, alkyl groups, and alkoxy groups include R in general formulas (1) and (2). 1 ~R 18 Examples include those similar to those described as individual groups.

[0041] Examples of heteroaryl groups include heteroaryl groups having 3 to 15 atoms constituting the ring, and may be monocyclic or fused rings. Examples of heteroatoms include nitrogen, oxygen, sulfur, silicon, phosphorus, and germanium atoms, and may contain multiple atoms of these. Specific examples of heteroaryl groups include pyridyl, pyrimidyl, pyrazyl, triazyl, benzofuranyl, benzothiophenyl, dibenzofuranyl, dibenzothiophenyl, oxazolyl, oxadiazolyl, thiazolyl, thiadiazolyl, carbazolyl, acridinyl, and phenanthrolyl groups. Heteroaryl groups may be substituted with halogen atoms, cyano groups, alkyl groups, or alkoxy groups. Examples of halogen atoms, alkyl groups, and alkoxy groups include R in general formulas (1) and (2). 1 ~R 18 Examples include those similar to those described as individual groups.

[0042] Examples of aryloxy groups include those in which the aryl portion has 6 to 30 carbon atoms. Specifically, examples of aryloxy groups include phenoxy groups and naphthoxy groups. The aryloxy group may be substituted with a halogen atom, a cyano group, an alkyl group, or an alkoxy group. Examples of halogen atoms, alkyl groups, and alkoxy groups include R in general formulas (1) and (2). 1 ~R 18 Examples include those similar to those described as individual groups.

[0043] Examples of heteroaryloxy groups include heteroaryloxy groups having 3 to 15 atoms constituting the ring of the heteroaryl moiety, and may be monocyclic or fused rings. Examples of heteroatoms include R in general formulas (1) and (2). 1 ~R 18 Examples of heteroaryloxy groups include those similar to the heteroatom of the heteroaryl group. Specifically, examples of heteroaryloxy groups include pyridyloxy, pyrimidyloxy, pyrazyloxy, triazyloxy, benzofuryloxy, dibenzofuryloxy, benzothienyloxy, dibenzothienyloxy, pyryloxy, indolyloxy, and N-methylcarbazolyloxy.

[0044] A silyl group is a group in which an alkyl group, aryl group, or alkoxy group is substituted on a silicon atom. Examples of silyl groups include trialkylsilyl groups, dialkylarylsilyl groups, alkyldiarylsilyl groups, and triarylsilyl groups. Among these, silyl groups substituted with an alkyl group having 1 to 8 carbon atoms or an aryl group having 6 to 10 carbon atoms are preferred. Specifically, examples include trimethylsilyl groups, tert-butyldimethylsilyl groups, triisopropylsilyl groups, and tert-butyldiphenylsilyl groups.

[0045] Examples of acyl groups include those having 1 to 20 carbon atoms. Specifically, examples of acyl groups include the formyl group, acetyl group, propionyl group, and benzoyl group.

[0046] Examples of alkoxycarbonyl groups include alkoxycarbonyl groups having 2 to 20 carbon atoms. Specific examples of alkylcarbonyl groups include methoxycarbonyl groups, ethoxycarbonyl groups, and hexyloxycarbonyl groups.

[0047] In general formulas (1) and (2), ring A represents an aryl ring or a heteroaryl ring. Ring A may be substituted with any of the groups listed above, namely a halogen atom, alkyl group, cycloalkyl group, alkoxy group, aryl group, heteroaryl group, aryloxy group, heteroaryloxy group, silyl group, alkoxycarbonyl group, acyl group, or cyano group. The aryl ring of ring A may be an aryl ring having 6 to 30 carbon atoms, and may be a monoring or a fused ring. In particular, the aryl ring of ring A in general formulas (1) and (2) is preferably a benzene ring, naphthalene ring, fluorene ring, phenanthrene ring, 9,9-spirobifluorene ring, or chrysene ring. As for the heteroaryl ring of ring A, R in general formulas (1) and (2) is... 1 ~R 18 Examples include those similar to those described as heteroaryl groups. Specifically, these include pyridine rings, pyrimidine rings, pyrazine rings, triazine rings, benzofuran rings, benzothiophene rings, dibenzofuran rings, dibenzothiophene rings, oxazoline rings, oxadiazole rings, thiazole rings, thiadiazole rings, carbazole rings, acridine rings, and phenanthroline rings.

[0048] In general formulas (1) and (2), L 1 -L 2 is a bidentate ligand represented by at least one of the general formulas (3) to (5). In general formulas (3) to (5), R 19 ~R 33 Each of these independently represents a hydrogen atom, a deuterium atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an aryl group, or a heteroaryl group. 19 ~R 33 The halogen atoms, alkyl groups, cycloalkyl groups, alkoxy groups, aryl groups, and heteroaryl groups are R1 ~R 18 Examples include those similar to those described as individual groups.

[0049] Specific examples of organometallic complexes (compounds represented by general formula (1) and general formula (2)) are shown below. Of course, in the present invention, the following specific examples are not limited to those that fall under the definitions of general formula (1) and general formula (2).

[0050] [ka]

[0051] [ka]

[0052] [ka]

[0053] [ka]

[0054] The content (ppm) of organometallic complexes in the luminescent composition is preferably 1 ppm to 3,000 ppm based on the total mass of the luminescent composition. Furthermore, the content (ppm) of organometallic complexes in the luminescent composition is preferably 0.001 to 0.20 times the total mass ratio of the fluorene oligomer content (ppm) and the polymer host material content (ppm). By setting the mass ratio within the above range, energy transfer from the host occurs efficiently, and aggregation of the organometallic complexes can be suppressed. As a result, the emission quantum yield of dopant emission can be further increased, and the emission quantum yield of the host relative to the dopant can be further effectively suppressed.

[0055] (Fluorene oligomer) The luminescent composition contains a fluorene oligomer which is a compound comprising a unit represented by the following general formula (6) and having 6 to 14 repeating units. In this specification, a fluorene oligomer refers to one with a weight-average molecular weight of 1,000 to 10,000. This fluorene oligomer usually does not have a molecular weight distribution. Such a fluorene oligomer can be purified to high purity by purification methods such as column chromatography or gel permeation chromatography. The fluorene oligomer used in this invention contains a fluorene unit represented by general formula (6) and is chemically, thermally, and electrochemically stable. The fluorene oligomer can improve the emission quantum yield of dopant emission and therefore also functions as a host material itself.

[0056] [ka]

[0057] (In general formula (6), R 101 and R 102 Each of these independently represents a hydrogen atom, a deuterium atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an aryloxy group, or a heteroaryloxy group, and the multiple units represented by the general formula (6) are R 103 ~R 106 One of the following and R 107 ~R 110 It bonds with one of the following R molecules. R molecules that are not bonded to an adjacent molecular unit of general formula (6) 103 ~R 110 Each of these independently represents a hydrogen atom, a deuterium atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, a heteroaryl group, an aryloxy group, a heteroaryloxy group, or an amino group.

[0058] In general formula (6), R 101 and R 102Each of these independently represents a hydrogen atom, a deuterium atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an aryloxy group, or a heteroaryloxy group, and the multiple units represented by the general formula (6) are R 103 ~R 106 One of the following and R 107 ~R 110 It is bonded to one of the following: halogen atoms, alkyl groups, cycloalkyl groups, alkoxy groups, aryloxy groups, and heteroaryloxy groups are the same as those described for each group in the organometallic complex above.

[0059] R not bound to adjacent molecular units of general formula (6) 103 ~R 110 Each of these independently represents a hydrogen atom, a deuterium atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an aryl group, a heteroaryl group, an aryloxy group, a heteroaryloxy group, or an amino group. Examples of halogen atoms, alkyl groups, cycloalkyl groups, alkoxy groups, aryl groups, heteroaryl groups, aryloxy groups, and heteroaryloxy groups are the same as those described above for each group in organometallic complexes. The amino group may be a substituted amino group or an unsubstituted amino group. Examples of substituents for a substituted amino group include alkyl groups having 1 to 8 carbon atoms and aryl groups having 6 to 10 carbon atoms. Specific examples of substituted amino groups include dialkylamino groups, alkylarylamino groups, and diarylamino groups. More specifically, examples include dimethylamino groups, diisopropylamino groups, ethylphenylamino groups, diphenylamino groups, and morpholino groups.

[0060] Specific examples of fluorene oligomers are shown below. Of course, in the present invention, the following specific examples are not limited to those that are included in the definitions of general formula (1) and general formula (2). Preferably, the fluorene oligomer is at least one of the following compounds (101) to (118). These are fluorene oligomers composed only of the unit represented by general formula (6). By using these compounds, the emission quantum yield of dopant emission can be further improved, and the emission quantum yield of the host relative to the dopant can be further effectively suppressed.

[0061] [ka]

[0062] [ka]

[0063] [ka]

[0064] [ka]

[0065] The content of fluorene oligomers in the luminescent composition (ppm) is preferably 100 ppm or more and 10,000 ppm or less, based on the total mass of the luminescent composition. The content of fluorene oligomers in the luminescent composition (ppm) is preferably 0.10 times or more and 0.95 times or less in mass ratio to the total content of fluorene oligomers (ppm) and polymer host material (ppm). By setting the mass ratio within the above range, aggregation of the polymer host material can be efficiently suppressed and energy transfer can be efficiently mediated, thereby further effectively suppressing the luminescence quantum yield of the host relative to the dopant.

[0066] (Polymer host material) The luminescent composition contains a polymer host material. The polymer host material is preferably a material that functions as a host, and specifically, known materials can be used. In this specification, a polymer host material refers to a material with a weight-average molecular weight of 20,000 or more. The weight-average molecular weight of the polymer host material is preferably 3,000,000 or less, and more preferably 2,000,000 or less. In this specification, the weight-average molecular weight is a polystyrene-based value measured by gel permeation chromatography.

[0067] The polymer host material may be conjugated or unconjugated. Examples of conjugated polymer materials include polyfluorene, polyphenylene vinylene, fluorene-carbazole copolymer, fluorene-diphenylamine copolymer, fluorene-thiophene copolymer, fluorene-vinylene copolymer, and derivatives thereof. Examples of unconjugated polymer materials include polystyrene, polyvinylcarbazole, and derivatives thereof. The polymer host material can be used alone or in combination of multiple materials.

[0068] The polymer host material is preferably one that has charge transport properties, and more preferably one that has hole transport properties. Among these, the compound represented by the following general formula (7) is preferred as the polymer host material. This compound is a polyvinylcarbazole derivative and is preferred not only from the viewpoint of the luminescence quantum yield of the dopant emission and the luminescence quantum yield of the host relative to the dopant, but also from the viewpoint of thermal stability.

[0069] [ka]

[0070] (In general formula (7), R 201 ~R 208Each of these independently represents a hydrogen atom, a deuterium atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an aryl group, a heteroaryl group, an aryloxy group, or a heteroaryloxy group. n is between 50 and 10,000.

[0071] In general formula (7), R 201 ~R 208 Each of these independently represents a hydrogen atom, a deuterium atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an aryl group, a heteroaryl group, an aryloxy group, or a heteroaryloxy group. Examples of halogen atoms, alkyl groups, cycloalkyl groups, alkoxy groups, aryl groups, heteroaryl groups, aryloxy groups, and heteroaryloxy groups are the same as those described above for each group in organometallic complexes.

[0072] The content (ppm) of the polymer host material in the luminescent composition is preferably 100 ppm or more and 10,000 ppm or less, based on the total mass of the luminescent composition.

[0073] (Additives) In addition to the various materials mentioned above, the luminescent composition may contain various additives as needed, such as charge transport materials, resins, plasticizers, antioxidants, and ultraviolet absorbers. Among these, it is preferable to include resins and charge transport materials (e.g., electron transport materials). The resin is preferably a binder resin. Specifically, examples include polyvinylcarbazole resin, polycarbonate resin, polyester resin, ABS resin, acrylic resin, polyimide resin, phenolic resin, epoxy resin, silicone resin, and urea resin. The resin may be a homopolymer or a copolymer, and one or more resins may be used. Known materials can be used as electron transport materials. For example, 1,3-bis[2-(4-tert-butylphenyl)-1,3,4-oxadiazo-5-yl]benzene. Commercially available electron transport materials (e.g., trade name "OXD-7," manufactured by Lumnescence Technology) can also be used. The content (ppm) of electron-transporting material in the luminescent composition is preferably 10 ppm or more and 5,000 ppm or less, based on the total mass of the luminescent composition.

[0074] (liquid medium) The luminescent composition may be a liquid. To make a liquid luminescent composition, a liquid medium must be included. The liquid medium is not particularly limited as long as it can dissolve or disperse organometallic complexes, fluorene oligomers, and polymer host materials. In particular, it is preferable to use an organic solvent having a boiling point of 70°C to 300°C at 1 atmosphere. The organic solvent may be water-soluble or water-miscible. The content (mass%) of the organic solvent as the liquid medium in the liquid luminescent composition is preferably 90.0% to 99.5% by mass, based on the total mass of the luminescent composition.

[0075] Examples of organic solvents include aromatic hydrocarbon compounds such as toluene, o-xylene, p-xylene, mesitylene, chlorobenzene, o-dichlorobenzene, anisole, and phenylcyclohexane; alkyl halides such as dichloromethane and chloroform; ethers such as diethyl ether, dibutyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, and diethylene glycol dimethyl ether; ketones such as dimethoxyethane, cyclopentanone, cyclohexanone, and methyl ethyl ketone; esters such as ethyl acetate, butyl acetate, and methyl benzoate; amide compounds such as dimethylformamide and dimethylacetamide; and cyclic amide compounds (lactams) such as N-methylpyrrolidone and dimethylimidazolidinone. Ketones are particularly preferred. Organic solvents can be used to adjust various properties in the luminescent composition, such as the compatibility of various materials, the viscosity of the liquid, and surface tension. One or more organic solvents can be used.

[0076] <Organic light-emitting element> An example of an organic light-emitting element is one having a structure in which an insulating layer, a first electrode, an organic compound layer, and a second electrode are laminated on a substrate in this order. A protective layer and a color filter may be provided on the second electrode (in the direction opposite to the substrate). If a color filter is provided, a planarization layer may be provided between the protective layer and the color filter. One of the first electrode and the second electrode is the anode and the other is the cathode.

[0077] (substrate) The substrate can be made of materials such as quartz, glass, silicon, resin, and metal. Alternatively, switching elements such as transistors and wiring may be placed on the substrate, and an insulating layer may be provided on top of them. The insulating layer can be made of any material that allows for the formation of contact holes to ensure conductivity between the anode and the wiring, and provides insulation from wiring that should not be connected. Specific examples of insulating layers include those made of resins such as polyimide, and silicon compounds such as silicon oxide and silicon nitride.

[0078] (electrode) An organic light-emitting element is provided with a pair of electrodes. These electrodes are the anode and the cathode. When a voltage is applied in the direction of light emission, the electrode with the higher potential becomes the anode, and the other becomes the cathode. Alternatively, the electrode supplying holes to the light-emitting layer can be considered the anode, and the electrode supplying electrons can be considered the cathode.

[0079] The anode is preferably composed of materials with a high work function. Examples include metals such as gold, platinum, silver, copper, nickel, palladium, cobalt, selenium, vanadium, and tungsten; metal oxides such as tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide; mixtures and alloys thereof; and conductive polymers such as polyaniline, polypyrrole, and polythiophene. The electrode may be composed of one or more materials. The anode may also be composed of one or more layers.

[0080] For use as a reflective electrode, the anode can be made from materials such as metals like chromium, aluminum, silver, titanium, tungsten, and molybdenum; alloys or laminates of these metals can also be used. For use as a transparent electrode, oxides such as indium tin oxide (ITO) and indium zinc oxide can be used as the anode material. Photolithography can be used to form the anode.

[0081] On the other hand, materials with a small work function are preferred for the cathode. Examples include alkali metals such as lithium; alkaline earth metals such as calcium; other metals such as aluminum, titanium, manganese, silver, lead, and chromium; and oxides, mixtures, and alloys thereof. Examples of alloys include magnesium-silver, aluminum-lithium, aluminum-magnesium, silver-copper, and zinc-silver. Metal oxides such as indium tin oxide (ITO) may also be used. One or more types of materials may be used for the electrode components. The cathode may also be composed of one or more layers. Among these, the use of silver is preferred, and a silver alloy is even more preferred in order to suppress silver aggregation. The ratio of alloys is not a concern as long as silver aggregation is suppressed. For example, a ratio of about 1:1 may be used.

[0082] The cathode may be a top-emission element using an oxide conductive layer such as indium tin oxide (ITO), or a bottom-emission element using a reflective electrode such as aluminum (Al). Photolithography can also be used to form the cathode. Among these methods, sputtering (DC or AC) is preferred for forming the cathode. This is because the film formed by sputtering has excellent coverage and makes it easy to reduce resistance.

[0083] (protective layer) The protective layer can be provided on the cathode. For example, by bonding a glass with a desiccant layer onto the cathode, the intrusion of water and other substances into the organic compound layer can be suppressed, thereby preventing display defects. Alternatively, a passivation film such as silicon nitride may be provided on the cathode to suppress the intrusion of water and other substances into the organic compound layer. The protective layer can be formed by chemical vapor deposition (CVD). Alternatively, after film formation by chemical vapor deposition, a two-layer protective layer may be provided by atomic deposition (ALD). For example, after forming the cathode, it can be transported to another chamber while maintaining a vacuum, and a silicon nitride film can be formed as a protective layer by CVD. The thickness of the protective layer is preferably 1 μm to 10 μm.

[0084] (Color filter) The color filter can be placed on top of the protective layer. For example, a color filter corresponding to the size of the organic light-emitting element may be placed on a separate substrate and bonded to the substrate on which the organic light-emitting element is placed, or the color filter may be patterned using photolithography technology. The color filter can be made of polymer material or the like.

[0085] (flattening layer) A planarization layer can be provided between the color filter and the protective layer. Examples of constituent materials for the planarization layer include organic compounds, with high-molecular-weight organic compounds being particularly preferred. The planarization layer may be provided on both sides of the color filter; in this case, the constituent materials of each planarization layer may be the same or different. Examples of constituent materials for the planarization layer include polyvinylcarbazole resin, polycarbonate resin, polyester resin, ABS resin, acrylic resin, polyimide resin, phenolic resin, epoxy resin, silicone resin, and urea resin. Here, ABS resin is a resin composed of three monomers: acrylonitrile, butadiene, and styrene.

[0086] (Opposite substrate) The opposing substrate can be placed on top of the planarization layer. Because the opposing substrate is placed opposite the substrate, it is called an opposing substrate. The constituent materials of the opposing substrate are the same as those listed for the constituent materials of the substrate.

[0087] (organic compound layer) The organic compound layer constituting the organic light-emitting element comprises at least a pair of electrodes, a first electrode and a second electrode, and an organic compound layer that is a light-emitting layer positioned between the first electrode and the second electrode. The organic compound layer may be a single layer or a laminate having multiple layers, as long as it has a light-emitting layer.

[0088] If the organic compound layer is a laminate having multiple layers, at least one of the organic compound layers is an emissive layer. In addition to the emissive layer, the organic compound layer may also have a hole injection layer, a hole transport layer, an electron blocking layer, a hole-exciton blocking layer, an electron transport layer, an electron injection layer, and the like. The emissive layer may also be a single layer or a laminate having multiple layers. The hole transport layer and the electron transport layer are also called charge transport layers.

[0089] At least one of the organic compound layers of the organic light-emitting element contains the organometallic complex described above. Specifically, the organometallic complex is preferably contained in at least one layer such as a hole implantation layer, a hole transport layer, an electron blocking layer, an emissive layer, a hole-exciton blocking layer, an electron transport layer, or an electron implantation layer. In particular, it is preferable that it be contained in the emissive layer.

[0090] The first electrode, the light-emitting layer, and the transport layer placed between them all function to transport charge together; therefore, these layers can be treated collectively as the first charge transport layer. Similarly, the second electrode, the light-emitting layer, and the transport layer placed between them all function to transport charge together; therefore, these layers can be treated collectively as the second charge transport layer. Consequently, one surface of the light-emitting layer is in contact with the first charge transport layer, while the other surface is in contact with the second charge transport layer.

[0091] When an organometallic complex is included in the luminescent layer, the luminescent layer only needs to be formed of the organometallic complex and does not need to contain other components. That is, the luminescent layer may be a layer formed solely of the organometallic complex. The luminescent layer may also contain a first organic compound in addition to the organometallic complex. In this case, it is preferable that the lowest excited triplet energy of the first organic compound is equal to or greater than the lowest excited triplet energy of the organometallic complex and less than or equal to the lowest excited triplet energy of the fluorene oligomer. The luminescent layer may also contain an organometallic complex, a first organometallic compound, and a second organic compound different from the first organic compound. It is preferable that the lowest excited triplet energy of the second organic compound is equal to or greater than the lowest excited triplet energy of the organometallic complex and less than or equal to the lowest excited triplet energy of the first organic compound. When the luminescent layer contains the first organic compound and the second organic compound, the first organic compound may be the host of the luminescent layer, and the second organic compound may be an assisting material. The organometallic complex may be a guest or a dopant.

[0092] The host is the component in the light-emitting layer that has the highest mass content. The guest or dopant is a component in the light-emitting layer that has a smaller mass content than the host and is responsible for the primary luminescence. The assist material is a component in the light-emitting layer that has a smaller mass content than the host and assists the luminescence of the guest. The assist material is also called the second host.

[0093] When organometallic complexes are used as guests in the luminescent layer, the guest content (mass%) is preferably 0.01% to 20.0% by mass, and more preferably 0.1% to 10.0% by mass, based on the total mass of the luminescent layer. The total mass of the luminescent layer refers to the total content of the components constituting the luminescent layer.

[0094] Furthermore, it is preferable that the lowest excited triplet energy of the first charge transport layer is greater than the lowest excited triplet energy of either the polymer host material or the fluorene oligomer. In addition, it is preferable that the lowest excited triplet energy of the second charge transport layer is greater than the lowest excited triplet energy of either the polymer host material or the fluorene oligomer. The lowest excited triplet energy of the charge transport layer can be estimated using the lowest excited triplet energy of the constituent materials of the layer. If the charge transport layer is composed of multiple materials, it may be considered as the lowest excited triplet energy of the compound with the largest mass-based content.

[0095] The thickness of each layer constituting the organic light-emitting element is preferably 1 nm to 10,000 nm (10 μm or less), independently of the others. In particular, from the viewpoint of obtaining excellent light emission characteristics, a thickness of 10 nm to 100 nm is preferred.

[0096] <Method for manufacturing organic light-emitting elements> A method for manufacturing an organic light-emitting element having an organic compound layer (such as a hole injection layer, hole transport layer, electron blocking layer, light-emitting layer, hole blocking layer, electron transport layer, or electron injection layer) is described. The organic light-emitting element is manufactured by a manufacturing method that includes the step of applying a light-emitting composition to a substrate to form an organic compound layer.

[0097] Methods for forming an organic compound layer include, for example, dry processes and wet processes. Dry processes include, for example, vacuum deposition, ionization deposition, sputtering, and plasma processes. Wet processes are methods for applying a liquid luminescent composition to a substrate by known methods. Methods for applying a liquid luminescent composition to a substrate include, for example, coating methods such as spin coating, casting, gravure coating, bar coating, roll coating, wire bar coating, dip coating, spray coating, capillary coating, and spray coating; and printing methods such as screen printing, flexographic printing, offset printing, and inkjet printing. Among these, vacuum deposition, ionization deposition, spray coating, and inkjet printing are preferred. The above methods are suitable from the viewpoint of being able to manufacture large-area organic light-emitting devices. In particular, inkjet printing is preferred.

[0098] It is preferable to form an organic compound layer by a wet process and then dry the liquid medium. The drying conditions can be appropriately set according to the constituent materials such as the organic compound layer. It is preferable to dry in an air or inert gas (nitrogen, argon, etc.) atmosphere. The heating temperature for drying is preferably 100°C to 250°C, and more preferably 110°C to 200°C. The heating time for drying is preferably 5 minutes to 60 minutes. The pressure during heating for drying may be at normal pressure (1 atmosphere) or under reduced pressure (100 Pa to 0.1 MPa). The various conditions (temperature, pressure, and time) in the drying process should be set so that the liquid medium can be removed from the organic compound layer, etc.

[0099] When forming an organic compound layer by a wet process using a liquid luminescent composition, it is preferable to appropriately determine the composition. The content (mass%) of the organic solvent as a liquid medium in the luminescent composition is preferably 10.0 to 100.0 times the total mass ratio of the content (mass%) of the solid components constituting the organic compound layer. Examples of solid components constituting the organic compound layer include organometallic complexes, fluorene oligomers, and polymer host materials.

[0100] When applying a liquid luminescent composition to a substrate using an inkjet method to form an organic compound layer, it is preferable to appropriately control its physical properties. The surface tension of the liquid luminescent composition at 25°C is preferably 15 mN / m to 75 mN / m, and more preferably 25 mN / m to 45 mN / m. The surface tension of the liquid luminescent composition can be adjusted by appropriately determining the type and content of the organic solvent in the luminescent composition. Furthermore, the viscosity of the liquid luminescent composition at 25°C is preferably 0.1 mPa·s to 20.0 mPa·s, and more preferably 0.5 mPa·s to 10.0 mPa·s. By setting the viscosity within the above range, clogging and ejection failures in the liquid ejection head during inkjet ejection can be suppressed.

[0101] <Pixel Circuit> The organic light-emitting device may have a pixel circuit connected to an organic light-emitting element. The pixel circuit is preferably an active-matrix type that independently controls the light emission of each of the multiple organic light-emitting elements. The active-matrix circuit may be voltage-programmed or current-programmed. The drive circuit has a pixel circuit for each pixel. The pixel circuit may further include a transistor for controlling the light emission brightness of the organic light-emitting element, a transistor for controlling the light emission timing, a capacitor for holding the gate voltage of the transistor controlling the light emission brightness, and a transistor for connecting to ground without going through the organic light-emitting element.

[0102] The organic light-emitting device has a display area and a peripheral area arranged around the display area. The display area has a pixel circuit, and the peripheral area has a display control circuit. The mobility of the transistors constituting the pixel circuit may be smaller than the mobility of the transistors constituting the display control circuit. The slope of the current-voltage characteristic of the transistors constituting the pixel circuit may be smaller than the slope of the current-voltage characteristic of the transistors constituting the display control circuit. The slope of the current-voltage characteristic can be measured by the so-called Vg-Ig characteristic. The transistors constituting the pixel circuit are transistors connected to the organic light-emitting element.

[0103] <Pixel> The organic light-emitting device has multiple pixels. Each of the multiple pixels has sub-pixels that emit light of a different color from the others. Each sub-pixel independently has a light-emitting color of red (R), green (G), and blue (B). The pixels emit light in a region also called the pixel aperture. The pixel aperture is preferably 15 μm or less, and preferably 5 μm or more. The pixel aperture can be, for example, 11.0 μm, 9.5 μm, 7.4 μm, 6.4 μm, etc. The distance between sub-pixels is preferably 10 μm or less. The distance between sub-pixels can be, for example, 8.0 μm, 7.4 μm, 6.4 μm, etc.

[0104] The planar arrangement of pixels can be a known form. Specifically, examples include stripe arrangement, delta arrangement, pentile arrangement, and Bayer arrangement. The planar shape of subpixels can be a known shape. Specifically, examples include rectangles, rhombuses, and other quadrilaterals and hexagons. Here, the planar shape of a subpixel does not need to be an exact shape; if it is close to a rectangle, it will be judged as a rectangle. The planar shape of subpixels and the pixel arrangement can be used in combination.

[0105] <Applications of organic light-emitting diodes> Organic light-emitting elements can be used as components in display devices and lighting equipment. Other applications include exposure light sources for electrophotographic image recording devices, backlights for liquid crystal display devices, and light-emitting devices with color filters in a white light source.

[0106] The display device has an image input unit that receives image information from an area CCD, linear CCD, memory card, etc., and an information processing unit that processes the input information. CCD stands for Charge-Coupled Device. The display device may also be an image information processing device that displays the input image on a display unit. Furthermore, the display unit of an imaging device or inkjet recording device may have a touch panel function. Specific examples of drive methods for the touch panel function include infrared, capacitive, resistive, and electromagnetic induction methods. The display device may also be used as the display unit of a so-called hybrid recording device.

[0107] Next, the display device will be described with reference to the drawings. Figure 1(a) is a schematic cross-sectional view of an example of a pixel constituting the display device. The pixel has sub-pixels 10. The sub-pixels 10 are divided into 10R, 10G, and 10B based on their light emission. The emitted color may be distinguished and determined by the wavelength emitted from the light-emitting layer, or it may be determined by selective transmission or color conversion of the light emitted from the sub-pixels 10 using a color filter or the like. Each sub-pixel 10 has a reflective electrode 2 which is a first electrode, an insulating layer 3 covering the end of the reflective electrode 2, an organic compound layer 4 covering the first electrode and the insulating layer, a transparent electrode 5, a protective layer 6, and a color filter 7 on an interlayer insulating layer 1.

[0108] The interlayer insulating layer 1 may have transistors or capacitive elements placed beneath or inside it in the direction shown in the illustration. The transistors and the first electrode may be electrically connected via contact holes or the like (not shown). The insulating layer 3 is also called a bank or pixel separation layer. The insulating layer 3 covers the end of the first electrode and is arranged surrounding the first electrode. The portion where the insulating layer 3 is not placed is in contact with the organic compound layer 4 and becomes a light-emitting region. The organic compound layer 4 has 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. The second electrode may be a transparent electrode, a reflective electrode, or a semi-transparent electrode. The protective layer 6 reduces the penetration of liquid components such as water into the organic compound layer. The protective layer is shown as a single layer, but may consist of multiple layers. If it consists of multiple layers, it may include inorganic compound layers and organic compound layers. The color filter 7 is divided into 7R, 7G, and 7B according to its color. The color filter may be formed on a planarization film (not shown). Alternatively, the color filter may have a resin protective layer (not shown). Furthermore, the color filter may be formed on the protective layer 6, or it may be bonded to an opposing substrate such as a glass substrate after being provided on it.

[0109] Figure 1(b) is a schematic cross-sectional view showing an example of a display device comprising an organic light-emitting element 26 and a transistor connected to the organic light-emitting element 26. The transistor is an example of an active element. The transistor may also be a thin-film transistor (TFT). The display device 100 in Figure 1(b) consists of a substrate 11 made of glass, silicon, or the like, and an insulating layer 12 provided on top of the substrate 11. An active element 18, such as a TFT, is arranged on top of the insulating layer 12, and the gate electrode 13, gate insulating film 14, and semiconductor layer 15 of the active element are arranged thereon. The TFT 18 consists of a semiconductor layer 15, a drain electrode 16, and a source electrode 17. An insulating film 19 is provided on top of the TFT 18. The anode 21 and source electrode 17 constituting the organic light-emitting element are connected via a contact hole 20 provided in the insulating film. Note that the method of electrical connection between the electrodes (anode, cathode) included in the organic light-emitting element and the electrodes (source electrode, drain electrode) included in the TFT is not limited to the embodiment shown in Figure 1(b). In other words, it is sufficient that the anode or cathode is electrically connected to the TFT source electrode or drain electrode.

[0110] In the display device 100 shown in Figure 1(b), the organic compound layer is depicted as a single layer, but the organic compound layer 22 may consist of multiple layers. A first protective layer 24 and a second protective layer 25 are provided on the cathode 23 to reduce the degradation of the organic light-emitting element. In the display device 100 shown in Figure 1(b), a transistor is used as the switching element, but other switching elements may be used instead.

[0111] Furthermore, the transistor used in the display device 100 in Figure 1(b) is not limited to a transistor using a single-crystal silicon wafer, but may also be a thin-film transistor having an active layer on an insulating surface of the substrate. Examples of the active layer include non-single-crystal silicon such as single-crystal silicon, amorphous silicon, and microcrystalline silicon, and non-single-crystal oxide semiconductors such as indium zinc oxide and indium gallium zinc oxide.

[0112] The transistors included in the display device 100 in Figure 1(b) may be formed within a substrate such as a silicon substrate. Forming within a substrate means that the transistors are manufactured by processing a substrate such as a silicon substrate. In other words, having transistors within a substrate can be seen as the substrate and transistors being formed as a single unit.

[0113] The organic light-emitting element's luminescence is controlled by a TFT, which is an example of a switching element. By arranging multiple organic light-emitting elements on a surface, an image is displayed based on the luminescence of each element. Note that the switching element is not limited to a TFT; it may also be a transistor made of low-temperature polysilicon or an active matrix driver formed on a substrate such as a silicon substrate. The term "top or inside the substrate" can also be interpreted as "within the substrate." Whether to provide a transistor within the substrate or use a TFT is selected depending on the size of the display area. For example, if the size is about 0.5 inches, it is preferable to provide the organic light-emitting element on a silicon substrate.

[0114] Figure 2 is a schematic diagram representing an example of a display device. The display device 1000 has a touch panel 1003, a display panel 1005, a frame 1006, a circuit board 1007, and a battery 1008 between an upper cover 1001 and a lower cover 1009. Flexible printed circuits (FPCs) 1002 and 1004 are connected to the touch panel 1003 and the display panel 1005. Transistors are printed on the circuit board 1007. If the display device is a portable device, a battery 1008 is provided. Alternatively, the battery 1008 may be provided in a different location.

[0115] The display device may have a color filter having red (R), green (G), and blue (B). The color filter may be arranged in a delta array, a stripe array, or a mosaic array.

[0116] The display device can be used in the display section of a mobile device. In this case, it may have both display and operation functions. Examples of mobile devices include smartphones and other mobile phones, tablets, and head-mounted displays.

[0117] The display device can be used in the display unit of an imaging device having an optical unit with multiple lenses and an image sensor that receives light that has passed through the optical unit. The imaging device may have a display unit that displays information acquired by the image sensor. The display unit may be an external display unit or a display unit located inside the viewfinder. The imaging device may be a digital camera or a digital video camera. The imaging device may also be called a photoelectric converter.

[0118] Figure 3(a) is a schematic diagram showing an example of an imaging device. The imaging device 1100 includes a viewfinder 1101, a rear display 1102, an operating unit 1103, and a housing 1104. The viewfinder 1101 can use a display device. In that case, the display device may display not only the image to be captured, but also environmental information, imaging instructions, etc. Environmental information may include the intensity of ambient light, the direction of ambient light, the speed at which the subject is moving, and the possibility that the subject may be obscured by an obstruction.

[0119] Since the optimal timing for imaging is only a short time, it is preferable to be able to display information quickly. Because organic light-emitting elements have a fast response speed, the display device using the organic light-emitting elements of the present invention can be suitably applied. The imaging device 1100 has an optical section (not shown). The optical section has multiple lenses and forms an image on the image sensor housed in the housing 1104. The focus can be adjusted by adjusting the relative positions of the multiple lenses. This operation can also be performed automatically.

[0120] Figure 3(b) is a schematic diagram representing an example of an electronic device. The electronic device 1200 has a display unit 1201, an operating unit 1202, and a housing 1203. The housing 1203 has a circuit, a printed circuit board with the circuit, a battery, and a communication unit. The operating unit 1202 may be a button or a touch panel type response unit. The operating unit 1202 may also be a biometric recognition unit that recognizes fingerprints to unlock the device. 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. In this case, the image captured by the camera function is displayed on the display unit 1201. Examples of the electronic device 1200 include smartphones and laptop computers.

[0121] Figure 4 is a schematic diagram showing an example of a display device. Figure 4(a) is a display device used as a monitor for televisions, personal computers, etc. The display device 1300 has a frame 1301, a display unit 1302, and a base that supports the display unit 1302. The display unit 1302 uses a light-emitting device. The base 1303 is not limited to the form shown in Figure 4(a), and the lower edge of the frame 1301 may also serve as the base. In addition, the frame 1301 and the display unit 1302 may be curved. The radius of curvature is preferably 5,000 mm or more and 6,000 mm or less.

[0122] Figure 4(b) is a schematic diagram representing another example of a display device. The display device 1310 in Figure 4(b) is configured to be foldable and is a so-called foldable display device. The display device 1310 has a first display unit 1311, a second display unit 1312, a housing 1313, and a bending point 1314. The first display unit 1311 and the second display unit 1312 may be light-emitting devices. The first display unit 1311 and the second display unit 1312 may be a single display device without seams. The first display unit 1311 and the second display unit 1312 can be separated at the bending point. The first display unit 1311 and the second display unit 1312 may each display different images or may display a single image.

[0123] Figure 5(a) is a schematic diagram showing an example of a lighting device. The lighting device 1400 includes a housing 1401, a light source 1402, a circuit board 1403, an optical film 1404, and a light diffusion section 1405. An organic light-emitting element can be used as the light source. The optical filter may be a filter that improves the color rendering of the light source. The light diffusion section effectively diffuses the light from the light source, such as for lighting up, and can deliver light over a wide area. The optical filter and light diffusion section may be provided on the light-emitting side of the lighting. A cover may be provided on the outermost part as needed.

[0124] A lighting device is, for example, a device for illuminating a room, and comprises a light source and a component that transmits the light emitted by the light source. The lighting device may emit light in any color from blue to red, not just white or cool white. Here, "white" refers to a color temperature of approximately 4,200K, and "cool white" refers to a color temperature of approximately 5,000K. The lighting device may have a dimming circuit to adjust the brightness. The lighting device may also have an organic light-emitting element and a power supply circuit connected thereto. The power supply circuit is a circuit that converts AC voltage to DC voltage. The lighting device may have a light-diffusing section or a color filter as a component that transmits the light emitted by the light source. The lighting device may also have a heat dissipation section. The heat dissipation section releases heat from inside the device to the outside, and examples include metals with high specific heat or liquid silicon.

[0125] Figure 5(b) is a schematic diagram of an automobile, which is an example of a mobile vehicle. The automobile has a taillight, which is an example of a lighting device. The automobile 1500 may have a taillight 1501, and the taillight may be configured to illuminate when the brakes are applied or when other actions are taken.

[0126] The tail lamp 1501 may have an organic light-emitting element. The tail lamp may also have a protective member to protect the organic light-emitting element. Any protective member can be suitably used as long as it has a reasonably high strength and is transparent. Among these, it is preferable that it be composed of polycarbonate. A frangic acid derivative or an acrylonitrile derivative may be mixed with the polycarbonate.

[0127] The automobile 1500 may have a body 1503 and windows 1502 attached thereto. The windows may be transparent displays unless they are for checking the front and rear of the automobile. The transparent displays may have organic light-emitting elements. In this case, the constituent materials such as electrodes having the organic light-emitting elements are made of transparent components.

[0128] The mobile entity may be a ship, aircraft, drone, etc. The mobile entity may have a body and a light fixture installed on the body. The light fixture may emit light to indicate the position of the entity. The light fixture has an organic light-emitting element.

[0129] Refer to Figure 6 to describe examples of display device applications. The display device can be applied to systems that can be worn as wearable devices, such as smart glasses, head-mounted displays, and smart contact lenses. The imaging display device used in such applications comprises an imaging device capable of photoelectric conversion of visible light and a display device capable of emitting visible light.

[0130] Referring to Figure 6(a), the eyeglasses 1600 (smart glasses) will be described. An imaging device 1602, such as a CMOS sensor or SPAD sensor, is provided on the front surface of the lens 1601 of the eyeglasses 1600. Here, a CMOS (Complementary Metal-Oxide-Semiconductor) sensor is a solid-state image sensor using complementary metal-oxide-semiconductor. A SPAD (Single Photon Avalanche Diode) sensor is a sensor that has an electronic element that outputs a single large electrical pulse signal through avalanche-like multiplication when a single photon is incident on the pixel. A display device is also provided on the back surface of the lens 1601. The eyeglasses 1600 further includes a control device 1603. The control device 1603 functions as a power supply that provides power to the imaging device 1602 and the display device. The control device 1603 also controls the operation of the imaging device 1602 and the display device. An optical system for focusing light onto the imaging device 1602 is formed in the lens 1601.

[0131] Referring to Figure 6(b), the eyeglasses 1610 (smart glasses) will be described. The eyeglasses 1610 have a control device 1612, which is equipped with an imaging device equivalent to the imaging device 1602 and a display device. The lens 1611 has an optical system formed therein for projecting light emitted from the imaging device and display device in the control device 1612, and an image is projected onto the lens 1611. The control device 1612 functions as a power supply to supply power to the imaging device and display device, and also controls the operation of the imaging device and display device. The control device may have a gaze detection unit that detects the wearer's gaze. Gaze detection may use infrared light. The infrared light emitter emits infrared light towards the user's eyeball that is fixated on the displayed image. The imaging unit, which has a photodetector, detects the reflected light from the eyeball of the emitted infrared light, thereby obtaining an image of the eyeball. By having a reduction means that reduces the light from the infrared light emitter to the display unit in planar view, the deterioration of image quality is reduced.

[0132] The eyeglasses 1610 detect the user's gaze toward the displayed image from an image of the eyeball obtained by imaging with infrared light. Any known method can be applied to gaze detection using an image of the eyeball. As an example, a gaze detection method based on the Purkinje image obtained by the reflection of the irradiated light from the cornea can be used. Specifically, gaze detection processing based on the pupil-corneal reflection method is performed. Using the pupil-corneal reflection method, the user's gaze is detected by calculating a gaze vector representing the orientation (rotation angle) of the eyeball based on the pupil image and the Purkinje image included in the image of the eyeball.

[0133] The display device may have an imaging device with a light-receiving element, and may control the display image of the display device based on the user's gaze information from the imaging device. Specifically, the display device determines a first field of view area that the user is fixated on, and a second field of view area other than the first field of view area, based on the gaze information. The first field of view area and the second field of view area may be determined by the control device of the display device, or they may be determined by an external control device and received. 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.

[0134] Furthermore, the display area has a first display area and a second display area different from the first display area, and based on line-of-sight information, the area with higher priority is determined from the first display area and the second display area. The first and second field-of-sight areas may be determined by the control device of the display device, or they may be determined by an external control device and received. The resolution of the high-priority area may be controlled to be higher than the resolution of the areas other than the high-priority area. In other words, the resolution of areas with relatively lower priority may be lower.

[0135] Artificial intelligence (AI) may be used to determine the first field of view area and high-priority areas. The AI ​​may be a model configured to estimate the angle of gaze and the distance to the target object at the end of the line of sight from the image of the eye, using the image of the eye and the direction the eye was actually looking in the image as training data. The AI ​​program may be contained in the display device, imaging device, or external device. If contained in an external device, it is transmitted to the display device via communication. When display control is based on visual detection, it is preferably applicable to smart glasses that further have an imaging device for capturing images of the outside. The smart glasses can display the captured external information in real time.

[0136] As described above, by using the device employing the organic light-emitting element of the present invention, it becomes possible to achieve stable display with good image quality even during long-term display. Furthermore, it is possible to achieve both good visibility outdoors due to high-efficiency, high-brightness light output and power-saving display. [Examples]

[0137] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited in any way by the following examples unless it exceeds the gist of the invention. Unless otherwise specified, amounts of "parts" and "%" are based on mass. Also, unless otherwise specified, 1 ppm can be converted to 0.0001 mass%.

[0138] <Preparation of luminescent composition> The organometallic complexes, fluorene oligomers, polymer host materials, additives, and 9,900 parts of the organic solvent cyclopentanone, according to the types and amounts (parts) listed in Tables 1 to 4, were mixed and stirred at 25°C for 24 hours. The mixtures were then filtered through a 0.2 μm pore size filter to prepare each luminescent composition (liquid luminescent composition). The composition (number of repeating units, functional groups) of the fluorene oligomers in Tables 1 to 4 is shown in Table 5. In Table 5, if a fluorene oligomer is a compound containing multiple units with different substituents, the functional group characterizing the compound is indicated.

[0139] The compounds listed in Tables 1 to 4 are as follows: Organometallic complexes 35, 41, 48: Compounds exemplified as organometallic complexes Organometallic complex 100: Compound represented by the following structural formula

[0140] [ka]

[0141] Fluorene oligomers 101, 105, 108, 109, 115, 116: Compounds exemplified above as fluorene oligomers. Fluorene oligomers 119-125: Compounds represented by the following structural formulas.

[0142] [ka]

[0143] Polymer host materials 201, 202, and 203: Compounds represented by the following structural formulas (polymer host materials 201 and 203 are compounds that possess hole transport properties). Weight-average molecular weight of polymer host material 201: approximately 1,100,000 Weight-average molecular weight of polymer host material 202: greater than 20,000 and less than or equal to 2,000,000 Weight-average molecular weight of polymer host material 203: 20,000~200,000

[0144] [ka]

[0145] Additive 301: Electron transport material represented by the following structural formula (product name "OXD-7", manufactured by Lumnescence Technology)

[0146] [ka]

[0147] [Table 1]

[0148] [Table 2]

[0149] [Table 3]

[0150] [Table 4]

[0151] [Table 5]

[0152] <Fabrication of organic light-emitting devices> Organic light-emitting devices were fabricated by sequentially depositing the anode, hole-injection layer, light-emitting layer, electron transport layer, and cathode on a substrate using the following procedure. For the transparent conductive support substrate (ITO substrate), a glass substrate was used on which ITO was deposited as the anode to a thickness of 100 nm by sputtering. The ITO substrate was washed with pure water, then isopropanol, and after UV-ozone treatment, the hole-injection layer was deposited by spin coating. The deposition conditions were as follows. • Coating solution: Poly(3,4-ethylenedioxythiophene) polystyrene sulfonic acid aqueous solution (PEDOT; PSS aqueous solution, manufactured by Aldrich, conductivity 1 × 10⁻⁶ -5 S / cm, compound content 2.8%) • Spin court conditions: 3,000 rpm, 60 seconds Annealing conditions: 200°C, 1 hour • Film thickness: 40nm

[0153] Next, the luminescent layer was fabricated using the spin coating method. The fabrication conditions were as follows: • Coating solution: Luminescent compositions listed in Tables 1 to 4 • Spin court conditions: 3,000 rpm, 60 seconds Annealing conditions: 110°C, 10 minutes • Film thickness: 30nm

[0154] Finally, the electron transport layer and electrode layer were fabricated by vacuum deposition using resistance heating. The area of ​​the opposing electrodes was 3 mm². 2 The film deposition conditions were as follows: ·Vacuum degree: 1×10 -5 Pa ·Electron transport layer: TPBi (50nm) ·Metal electrode layer: LiF (0.5nm), Al (90nm)

[0155] Subsequently, to prevent deterioration due to moisture absorption, a protective glass plate was placed over the organic light-emitting element in a dry air atmosphere, and the glass plate was sealed with an acrylic resin adhesive.

[0156] <Rating> The organic light-emitting element fabricated as described above was evaluated for the following items. In this invention, "A" and "B" were defined as acceptable levels, and "C" as unacceptable levels in the evaluation criteria for each of the following items. The evaluation results are shown in Table 6.

[0157] (Measurement of luminescence quantum yield) The luminescence quantum yield (PLQY(H)) of the host and the luminescence quantum yield (PLQY(D)) of the dopant were measured for the obtained organic light-emitting devices. The measurement conditions were 346 nm excitation light, 400-550 nm for the host emission region, and 550-800 nm for the dopant emission region, and the absolute luminescence quantum yield was measured using an absolute luminescence quantum yield analyzer (product name "C11347-01", manufactured by Hamamatsu Photonics).

[0158] (Quantum emission yield of dopant emission) The dopant's quantum emission yield was evaluated based on the PLQY(D) values ​​obtained from the above measurements, according to the evaluation criteria shown below. A: The value of PLQY(D) was 72% or higher. The value of B:PLQY(D) was between 70% and 72%. The value of C:PLQY(D) was less than 70%.

[0159] (Vitamin emission yield of the host relative to the dopant) From the PLQY(H) and PLQY(D) values ​​obtained from the above measurements, PLQY(H) / PLQY(D) was calculated, and the ratio of the host's emission quantum yield to the dopant was evaluated according to the evaluation criteria shown below. A larger PLQY(H) / PLQY(D) value indicates that the host's emission has a greater influence on the color of the dopant's emission. A: The value of PLQY(H) / PLQY(D) was 6.5% or less. The value of B:PLQY(H) / PLQY(D) was greater than 6.5% and less than or equal to 11.0%. The value of C:PLQY(H) / PLQY(D) exceeded 11.0%.

[0160] [Table 6]

[0161] The luminescent composition of Example 12 received the same B rank as the luminescent composition of Example 13, but the luminescent composition of Example 13 was superior in terms of the emission quantum yield of dopant emission and the host emission quantum yield relative to the dopant. Furthermore, the luminescent composition of Example 22 also received the same B rank as the luminescent compositions of Examples 9-13, 18, 23, and 24, but among these, the luminescent composition of Example 22 was inferior in terms of the emission quantum yield of dopant emission and the host emission quantum yield relative to the dopant.

[0162] As Reference Example 1, an organic light-emitting element was fabricated in the same manner as in Example 1, except that the inkjet method was used instead of the sputtering method, by sequentially depositing the anode, hole injection layer, light-emitting layer, electron transport layer, and cathode on a substrate. Both of the resulting organic light-emitting elements were evaluated as "A". [Explanation of Symbols]

[0163] 4 Organic compound layer 7 Color Filters 10 subpixels 11 circuit boards 16 Drain electrode 17 Source electrodes 18 Active elements 21 Anode 22 Organic compound layer 23 Cathode 26 Organic light-emitting diodes

Claims

1. A light-emitting composition comprising an organometallic complex, a fluorene oligomer, and a polymeric host material, The organometallic complex is at least one compound selected from the group consisting of a compound represented by the following general formula (1) and a compound represented by the following general formula (2): The fluorene oligomer is a compound containing a unit represented by the following general formula (6), and the number of repetitions of the unit is 6 or more and 14 or less. 【Chemistry 1】 (In general formulas (1) and (2), R １ ~R １８ each independently represents a hydrogen atom, a deuterium atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an aryl group, a heteroaryl group, an aryloxy group, a heteroaryloxy group, a silyl group, an alkoxycarbonyl group, an acyl group, or a cyano group. Ring A represents an aryl ring or a heteroaryl ring. L １ -L ２ is a bidentate ligand represented by any one of the following general formulas (3) to (5): 【Chemistry 2】 (In general formulas (3) to (5), R １９ ~R ３３ each independently represents a hydrogen atom, a deuterium atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an aryl group, or a heteroaryl group. 【Transformation 3】 (In general formula (6), R １０１ and R １０２ each independently represents a hydrogen atom, a deuterium atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an aryloxy group, or a heteroaryloxy group, and a plurality of units represented by the general formula (6) are １０３ ~R １０６ One of the following and R １０７ ~R １１０ Any R that is not bonded to an adjacent molecular unit of general formula (6) is bonded to any one of the R １０３ ~R １１０ each independently represents a hydrogen atom, a deuterium atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an aryl group, a heteroaryl group, an aryloxy group, a heteroaryloxy group, or an amino group.

2. 2. The light-emitting composition according to claim 1, wherein the aryl ring of the ring A is a benzene ring, a naphthalene ring, a fluorene ring, a phenanthrene ring, a 9,9-spirobifluorene ring, or a chrysene ring.

3. 2. The luminescent composition according to claim 1, wherein the fluorene oligomer is at least one of the following compounds (101) to (118): 【Chemistry 4】 【Transformation 5】 【Transformation 6】 【Transformation 7】

4. 2. The light-emitting composition according to claim 1, wherein the polymer host material has hole-transporting properties.

5. 2. The light-emitting composition according to claim 1, wherein the polymer host material is a compound represented by the following general formula (7): 【Transformation 8】 (In general formula (7), R ２０１ ~R ２０８ each independently represents a hydrogen atom, a deuterium atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an aryl group, a heteroaryl group, an aryloxy group, or a heteroaryloxy group; and n is 50 or more and 10,000 or less.

6. 2. The luminescent composition according to claim 1, wherein the content (ppm) of the fluorene oligomer in the luminescent composition is 0.10 times or more and 0.95 times or less in mass ratio to the sum of the content (ppm) of the fluorene oligomer and the content (ppm) of the polymer host material.

7. 2. The luminescent composition according to claim 1, wherein the content (ppm) of the organometallic complex in the luminescent composition is 0.001 times or more and 0.20 times or less in mass ratio to the sum of the content (ppm) of the fluorene oligomer and the content (ppm) of the polymer host material.

8. The luminescent composition of claim 1 , wherein the luminescent composition is a liquid.

9. An organic light-emitting device having a first electrode, a second electrode, and an organic compound layer that is a light-emitting layer disposed between the first electrode and the second electrode, An organic light-emitting device, wherein the organic compound layer is formed from the light-emitting composition according to claim 1 .

10. the light-emitting layer further comprises a first organic compound; 10. The organic light-emitting element according to claim 9, wherein the lowest excited triplet energy of the first organic compound is equal to or higher than the lowest excited triplet energy of the organometallic complex and equal to or lower than the lowest excited triplet energy of the fluorene oligomer.

11. 11. The organic light-emitting element according to claim 10, wherein the organic compound layer further comprises a first charge transport layer between the first electrode and the light-emitting layer and in contact with the first electrode, and a second charge transport layer between the second electrode and the light-emitting layer and in contact with the second electrode.

12. 12. The organic light-emitting element according to claim 11, wherein the lowest excited triplet energy of the first charge transport layer is greater than the lowest excited triplet energy of both the polymer host material and the fluorene oligomer, and the lowest excited triplet energy of the second charge transport layer is greater than the lowest excited triplet energy of both the polymer host material and the fluorene oligomer.

13. A display device having a plurality of pixels and a transistor connected to the plurality of pixels, A display device, wherein at least one of the plurality of pixels is the organic light-emitting element according to claim 9.

14. An imaging element having an optical unit having a plurality of lenses, an imaging element that receives light that has passed through the optical unit, and a display unit that displays an image captured by the imaging element, An imaging device, wherein the display section includes the organic light-emitting element according to claim 9.

15. An electronic device having a display unit, a housing in which the display unit is provided, and a communication unit provided in the housing and communicating with an external device, An electronic device, wherein the display unit includes the organic light-emitting element according to claim 9.

16. A lighting device having a light source and a member that transmits light emitted by the light source, A lighting device, wherein the light source comprises the organic light-emitting element according to claim 9.

17. A moving body having a lighting fixture and a body on which the lighting fixture is provided, A moving body, wherein the lighting device comprises the organic light-emitting element according to claim 9.

18. A method for producing an organic light-emitting device, comprising the step of applying the light-emitting composition according to claim 1 to a substrate.

19. A method for producing an organic light-emitting device, comprising the step of applying the light-emitting composition according to claim 8 to a substrate by a coating method or a printing method.

20. 20. The method for producing an organic light-emitting element according to claim 19, wherein the coating method is a spin coating method, a casting method, a gravure coating method, a bar coating method, a roll coating method, a wire bar coating method, a dip coating method, a spray coating method, a capillary coating method, or a spray coating method.

21. The method for producing an organic light-emitting element according to claim 19, wherein the printing method is a screen printing method, a flexographic printing method, an offset printing method, or an inkjet printing method.

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