Iridium complex compound, iridium complex compound-containing composition, organic electroluminescent device and method for producing the same

Abstract

Provided is an iridium complex compound represented by formula (1). The iridium complex compound has high solubility in solvents, exhibits excellent luminous efficiency when used in an organic EL element, and achieves an excellent operational lifespan. In formula (1), Ir denotes an iridium atom. n is 1 or 2. Ar is a structure represented by formula (2). In formula (2), the dotted line indicates a bond to Ar in formula (1). m is an integer having a value of n+1 to n+5. Substituent groups R and R1 in formula (1) and formula (2) are preferably hydrogen atoms or D.

Description

[Technical Field]

[0001] The present invention relates to an iridium complex compound and an iridium complex compound-containing composition, and in particular to an iridium complex compound useful as a material for the light-emitting layer of an organic electroluminescent device (hereinafter sometimes referred to as an "organic EL device") and an iridium complex compound-containing composition containing the iridium complex compound. The present invention also relates to an organic electroluminescent device containing the iridium complex compound and a method for producing the same. [Background technology]

[0002] Various electronic devices that use organic electroluminescent (EL) elements, such as organic EL lighting and displays, have been put to practical use. Organic electroluminescent elements consume little power due to the low applied voltage, and are also capable of emitting the three primary colors. For this reason, they are beginning to be applied not only to large display monitors, but also to small and medium-sized displays such as those found in mobile phones and smartphones.

[0003] Organic electroluminescent devices are manufactured by stacking multiple layers, such as a light-emitting layer, a charge injection layer, and a charge transport layer. Currently, most organic electroluminescent devices are manufactured by depositing organic materials under vacuum. The vacuum deposition method involves a complicated deposition process, resulting in poor productivity. Organic electroluminescent devices manufactured by the vacuum deposition method have the problem that it is extremely difficult to enlarge the panels for lighting or displays. For this reason, in recent years, wet film formation methods (coating methods) have been actively researched as a process for efficiently manufacturing organic electroluminescent elements that can be used in large displays and lighting. The wet film formation method has the advantage of being able to easily form stable layers compared to vacuum deposition methods. For this reason, it is expected to be used in the mass production of displays and lighting devices and in large devices.

[0004] To manufacture organic electroluminescent devices using a wet film-forming method, all materials used must be able to dissolve in organic solvents and be used as ink. If the materials used have poor solvent solubility, they may deteriorate before use due to the need for long-term heating or other operations. Furthermore, if the solution cannot be maintained in a homogeneous state for a long period of time, the materials will precipitate from the solution, making film formation using an inkjet device or other similar device impossible. That is, materials used in wet film-forming methods are required to have solubility in two senses: they must dissolve quickly in organic solvents, and after dissolving, they must remain in a homogeneous state without precipitating.

[0005] On the other hand, the performance required for organic electroluminescent devices is to improve luminous efficiency and extend their operating life. If these requirements cannot be met simultaneously, it will be difficult to use them as organic EL display materials.

[0006] As described above, the light-emitting materials used in organic EL displays are required to have the following properties 1 to 3. 1. It has high solubility in solvents and remains uniform as an ink for a long period of time without reprecipitation. 2.High luminous efficiency. 3. Long operating life when used as an organic EL element. In particular, with regard to 1), efforts have been made to increase the concentration of the light-emitting material in the light-emitting layer in order to extend the operating life, and as a result, the development of a light-emitting material with higher solubility is eagerly awaited.

[0007] Iridium complex compounds that utilize phosphorescence have been used as light-emitting materials that have high luminous efficiency and can extend operating life. In particular, iridium complex compounds having phenyl-pyridine type ligands, such as those shown in Patent Documents 1 to 3, are known. Patent Document 1 discloses an iridium complex compound with a structure similar to that of the iridium complex compound of the present invention. However, in the iridium complex compound disclosed in Patent Document 1, the group corresponding to Ar in formula (1) of the present invention is a phenyl group, biphenyl group, or terphenyl group, and the number of linked benzene rings is smaller than that of the iridium complex compound of the present invention. Furthermore, the iridium complex compound does not have multiple linked meta-phenylene groups. Patent Documents 2 and 3 also disclose a wide range of iridium complex compounds, but do not suggest the iridium complex compound of the present invention.

[0008] [Patent Document 1] International Publication No. 2013 / 142634 [Patent Document 2] International Publication No. 2004 / 026886 [Patent Document 3] International Publication No. 2020 / 230811

[0009] The compound disclosed in Patent Document 1 has low solubility in solvents and is difficult to make into a high-concentration ink, so it is not possible to increase the concentration of the light-emitting material in the light-emitting layer and thereby extend the life of the device. Among the compounds disclosed in Patent Documents 2 and 3, those containing flexible substituents such as alkyl or aralkyl groups are presumed to have high solvent solubility. However, these substituents form insulating regions in the light-emitting layer, increasing the driving voltage of the device. Alternatively, these substituents may cause decomposition involving the cleavage of C—C bonds or C—H bonds, adversely affecting the operating life of the device. Summary of the Invention

[0010] An object of the present invention is to provide an iridium complex compound and a composition containing an iridium complex compound that have high solvent solubility and can further improve the luminous efficiency and operating life of a device. Another object of the present invention is to provide an organic electroluminescent device that uses this iridium complex compound and has excellent luminous efficiency and driving life.

[0011] The present inventors have found that an iridium complex compound having a specific chemical structure has high solvent solubility and also contributes to improving the luminous efficiency and driving life of a device.

[0012] The present invention provides the following.

[0013] [1] An iridium complex compound represented by the following formula (1):

[0014] [ka]

[0015] In formula (1), Ir represents an iridium atom, n is 1 or 2, and Ar has a structure represented by the following formula (2):

[0016] [ka]

[0017] In formula (2), the dashed line represents a bond to Ar in formula (1), and m is an integer of m=n+1 to n+5.

[0018] The substituents R in formula (1) and formula (2) are each independently a hydrogen atom, D or F. Substituent R in formula (1) and formula (2) 1are each independently a hydrogen atom, D, F, Cl, Br, I, -N(R')2, -CN, -NO2, -OH, -COOR', -C(=O)R', -C(=O)NR', -P(=O)(R')2, -S(=O)R', -S(=O)2R', -OS(=O)2R', a linear, branched, or cyclic alkyl group having from 1 to 6 carbon atoms, a linear, branched, or cyclic alkoxy group having from 1 to 4 carbon atoms, a linear, branched, or cyclic alkylthio group having from 1 to 4 carbon atoms, a linear or branched alkenyl group having from 2 to 4 carbon atoms, a linear or branched alkynyl group having from 2 to 4 carbon atoms, an aromatic group having from 5 to 60 carbon atoms, a heteroaromatic group having from 5 to 60 carbon atoms, a diarylamino group having from 10 to 40 carbon atoms, an arylheteroarylamino group having from 10 to 40 carbon atoms, or a diheteroarylamino group having from 10 to 40 carbon atoms. These groups may be substituted with one or more R's other than hydrogen atoms. Each R' is independently a hydrogen atom, D, F, -CN, a linear, branched, or cyclic alkyl group having from 1 to 6 carbon atoms, a linear or branched alkenyl group having from 2 to 4 carbon atoms, or a linear or branched alkynyl group having from 2 to 4 carbon atoms.

[0019] [2] The substituents R and R in the formula (1) and the formula (2) 1 [1] The iridium complex compound according to [1], wherein

[0020] [3] An iridium complex compound-containing composition comprising the iridium complex compound according to [1] or [2].

[0021] [4] The iridium complex compound-containing composition according to [3], further comprising an iridium complex compound represented by the following formula (3):

[0022] [ka]

[0023] In formula (3), Ir represents an iridium atom, and Ar has a structure represented by the following formula (2):

[0024] [ka]

[0025] In formula (2), the dashed line represents a bond to Ar in formula (3).

[0026] The substituents R in formula (3) and formula (2) are each independently a hydrogen atom, D or F. Substituent R in formula (3) and formula (2) 1 are each independently a hydrogen atom, D, F, Cl, Br, I, -N(R')2, -CN, -NO2, -OH, -COOR', -C(=O)R', -C(=O)NR', -P(=O)(R')2, -S(=O)R', -S(=O)2R', -OS(=O)2R', a linear, branched, or cyclic alkyl group having from 1 to 6 carbon atoms, a linear, branched, or cyclic alkoxy group having from 1 to 4 carbon atoms, a linear, branched, or cyclic alkylthio group having from 1 to 4 carbon atoms, a linear or branched alkenyl group having from 2 to 4 carbon atoms, a linear or branched alkynyl group having from 2 to 4 carbon atoms, an aromatic group having from 5 to 60 carbon atoms, a heteroaromatic group having from 5 to 60 carbon atoms, a diarylamino group having from 10 to 40 carbon atoms, an arylheteroarylamino group having from 10 to 40 carbon atoms, or a diheteroarylamino group having from 10 to 40 carbon atoms. These groups may be substituted with one or more R's other than hydrogen atoms. Each R' is independently a hydrogen atom, D, F, -CN, a linear, branched, or cyclic alkyl group having from 1 to 6 carbon atoms, a linear or branched alkenyl group having from 2 to 4 carbon atoms, or a linear or branched alkynyl group having from 2 to 4 carbon atoms.

[0027] [5] An organic electroluminescent device having at least an anode, a cathode, and at least one organic layer between the anode and the cathode on a substrate, At least one of the organic layers is an emitting layer, An organic electroluminescent device comprising the iridium complex compound according to [1] or [2] in the light-emitting layer.

[0028] [6] The organic electroluminescent device according to [5], wherein the light-emitting layer further contains an iridium complex compound represented by the following formula (3):

[0029] [ka]

[0030] In formula (3), Ir represents an iridium atom, and Ar has a structure represented by the following formula (2):

[0031] [ka]

[0032] In formula (2), the dashed line represents a bond to Ar in formula (3). The substituents R in formula (3) and formula (2) are each independently a hydrogen atom, D or F. Substituent R in formula (3) and formula (2) 1 are each independently a hydrogen atom, D, F, Cl, Br, I, -N(R')2, -CN, -NO2, -OH, -COOR', -C(=O)R', -C(=O)NR', -P(=O)(R')2, -S(=O)R', -S(=O)2R', -OS(=O)2R', a linear, branched, or cyclic alkyl group having from 1 to 6 carbon atoms, a linear, branched, or cyclic alkoxy group having from 1 to 4 carbon atoms, a linear, branched, or cyclic alkylthio group having from 1 to 4 carbon atoms, a linear or branched alkenyl group having from 2 to 4 carbon atoms, a linear or branched alkynyl group having from 2 to 4 carbon atoms, an aromatic group having from 5 to 60 carbon atoms, a heteroaromatic group having from 5 to 60 carbon atoms, a diarylamino group having from 10 to 40 carbon atoms, an arylheteroarylamino group having from 10 to 40 carbon atoms, or a diheteroarylamino group having from 10 to 40 carbon atoms. These groups may be substituted with one or more R's other than hydrogen atoms. Each R' is independently a hydrogen atom, D, F, -CN, a linear, branched, or cyclic alkyl group having from 1 to 6 carbon atoms, a linear or branched alkenyl group having from 2 to 4 carbon atoms, or a linear or branched alkynyl group having from 2 to 4 carbon atoms.

[0033] [7] The iridium complex compound-containing composition according to [3] or [4], further comprising a solvent.

[0034] [8] A method for manufacturing an organic electroluminescent device having at least an anode, a cathode, and at least one organic layer between the anode and the cathode on a substrate, comprising: At least one of the organic layers is an emitting layer, A method for producing an organic electroluminescent device, comprising forming the light-emitting layer by wet film formation of the iridium complex compound-containing composition according to [7].

[0035] [9] An organic electroluminescent device manufactured by the method of [8].

[0036]

[10] A display device comprising the organic electroluminescent element according to [6] or [9].

[0037]

[11] A lighting device comprising the organic electroluminescent element according to [6] or [9]. [Effects of the Invention]

[0038] According to the present invention, there are provided an iridium complex compound and an iridium complex compound-containing composition that have high solubility in solvents and that can further improve the luminous efficiency and driving life when used in an organic EL device.The present invention also provides an organic electroluminescent device that uses this iridium complex compound and has excellent luminous efficiency and driving life. [Brief explanation of the drawings]

[0039] [Figure 1] FIG. 1 is a cross-sectional view schematically showing an example of the structure of an organic electroluminescent device of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0040] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the preferred embodiments. The present invention is not limited to the following embodiments, and various modifications can be made within the scope of the present invention. In this specification, the term "aromatic ring" refers to an "aromatic hydrocarbon ring" and is distinguished from a "heteroaromatic ring" that contains a heteroatom as a ring-constituting atom. Similarly, the term "aromatic group" refers to an "aromatic hydrocarbon ring group," and the term "heteroaromatic group" refers to a "heteroaromatic ring group." "Solvent" and "solvent" are synonymous.

[0041] [Iridium complex compounds] The iridium complex compound of the present invention is an iridium complex compound represented by the following formula (1).

[0042] [ka]

[0043] In formula (1), Ir represents an iridium atom, n is 1 or 2, and Ar has a structure represented by the following formula (2):

[0044] [ka]

[0045] In formula (2), the dashed line represents a bond to Ar in formula (1), and m is an integer of m=n+1 to n+5.

[0046] The substituents R in formula (1) and formula (2) are each independently a hydrogen atom, D or F. Substituent R in formula (1) and formula (2) 1are each independently a hydrogen atom, D, F, Cl, Br, I, -N(R')2, -CN, -NO2, -OH, -COOR', -C(=O)R', -C(=O)NR', -P(=O)(R')2, -S(=O)R', -S(=O)2R', -OS(=O)2R', a linear, branched, or cyclic alkyl group having from 1 to 6 carbon atoms, a linear, branched, or cyclic alkoxy group having from 1 to 4 carbon atoms, a linear, branched, or cyclic alkylthio group having from 1 to 4 carbon atoms, a linear or branched alkenyl group having from 2 to 4 carbon atoms, a linear or branched alkynyl group having from 2 to 4 carbon atoms, an aromatic group having from 5 to 60 carbon atoms, a heteroaromatic group having from 5 to 60 carbon atoms, a diarylamino group having from 10 to 40 carbon atoms, an arylheteroarylamino group having from 10 to 40 carbon atoms, or a diheteroarylamino group having from 10 to 40 carbon atoms. These groups may be substituted with one or more R's other than hydrogen atoms. Each R' is independently a hydrogen atom, D, F, -CN, a linear, branched, or cyclic alkyl group having from 1 to 6 carbon atoms, a linear or branched alkenyl group having from 2 to 4 carbon atoms, or a linear or branched alkynyl group having from 2 to 4 carbon atoms.

[0047] <Mechanism> The iridium complex compound of the present invention has higher solvent solubility than conventional materials and also contributes to improving the luminous efficiency and driving life of the device. The reason for this is presumed to be as follows.

[0048] In the widely known iridium complex, tris(2-phenylpyridine)iridium complex [Ir(ppy)3], the iridium atom has a high electron-donating property. This results in high electron density at the para-position of the benzene ring covalently bonded to the iridium atom. This site is highly susceptible to oxidation and radical attack. When a device using [Ir(ppy)3] as the light-emitting material is operated, the redox reaction that occurs in the light-emitting layer causes [Ir(ppy)3] to rapidly react with surrounding cation radical species and transform into a different substance. This shortens the operating life. Therefore, by substituting a phenyl group in advance at the para position of the benzene ring of [Ir(ppy)3], it is possible to suppress the deterioration to some extent. However, the electrons flowing in from the iridium atoms increase the electron density at the para position of the substituted phenyl group due to resonance, so the degree of degradation inhibition is not sufficient. As in the present invention, by substituting a para-biphenyl group (which has an iridium atom-para-terphenyl group as a partial structure) or a para-terphenyl group (which also has an iridium atom-para-quaterphenyl group) to further extend the conjugated bond, the electrons flowing from the iridium atom are dispersed and accepted by three or more para-linked conjugated benzene rings. This prevents the generation of sites with high electron density. In other words, it is possible to sufficiently suppress deterioration due to oxidation reactions, and as a result, the operating life of the device can be extended.

[0049] Furthermore, factors that favorably affect the driving life will be explained below. In the iridium complex compound of the present invention, the HOMO is widely distributed between the iridium atom and the terphenylene moiety through π-conjugation, making the iridium complex more susceptible to hole injection in the light-emitting layer. The oxidized iridium complex then recombines with electrons to generate excitons. Because excitons are generated on the iridium complex, there is less opportunity for energy to be dissipated into other quenching processes compared to when excitons are recombined on the host and then energy is transferred to the iridium complex. This results in higher luminous efficiency. If an iridium complex having such a structure that facilitates the transfer of holes can be present in a high concentration in the light-emitting layer, it will be possible to more easily conduct hopping of holes between the iridium complexes, and as a result, recombination on the iridium complexes can occur over a wider region of the light-emitting layer. One of the causes of impaired operating life is the localization of recombination sites within the light-emitting layer (for example, recombination occurring only near the interface between the light-emitting layer and the hole-transport layer). The excited state of the iridium complex generated by recombination is in a high energy state, so there is a path that not only leads to light emission but also to decomposition of the complex. When recombination sites are localized, only the iridium complex present at that site bears the burden of light emission for the entire device. This causes rapid deterioration and shortens operating life. Conversely, preventing the localization of recombination sites and allowing recombination to occur widely within the light-emitting layer can extend operating life.

[0050] In order to have a high concentration of iridium complex in the light-emitting layer (to the extent that concentration quenching does not occur), an ink (composition for forming a light-emitting layer) in which the iridium complex is dissolved at a high concentration is required. However, the para-terphenylene structure of the iridium complex of the present invention is a linear structure, unlike the bent meta-terphenylene structure, and therefore has poor solvent solubility, making it difficult to form the above-mentioned high-concentration ink. If a bent substituent such as an alkyl group or an aralkyl group is introduced to improve solvent solubility, the iridium complex is electrically insulated and shielded, which has a significant adverse effect on the exchange of holes and ultimately reduces the device life. However, when the meta(oligophenylene) skeleton represented by the above formula (2) is used, although the π-conjugated system is not extended, the presence of π-electrons in the oligophenylene skeleton can increase solvent solubility without being subject to insulating shielding. Here, if the number of benzene rings in the meta(oligophenylene) skeleton is too small, the solubility is insufficient, while if it is too large, the molecular size becomes too large, adversely affecting the hopping movement of holes. However, within the scope of the present invention, both of these can be achieved.

[0051] To facilitate the transfer of holes between iridium complexes in the light-emitting layer, it is preferable that all three bidentate ligands in the iridium complex are the ligands of the present invention, i.e., LIr (where L represents a bidentate ligand), as shown in formula (1). This is because in a complex containing even one ligand with a different structure, i.e., an LIrX (where X represents a bidentate ligand different from L) type complex, one-third of the space around the iridium complex is occupied by X, which is likely to impair hole injection and transport properties.

[0052] <n> In formula (1), n is 1 or 2. From the viewpoint of driving life, n=1 is preferred.

[0053] <Substituent> The substituents R and R in formula (1) and formula (2) 1 are independent of each other and may be the same or different. In formula (1), there is a benzene ring directly bonded to Ir and n benzene rings. In this specification, the benzene ring directly bonded to Ir is referred to as a "benzene ring (Ir)," and the n benzene rings are referred to as a "benzene ring (n)," and these are collectively referred to as "the benzene ring in formula (1)."

[0054] <Substituent R> As described in the previous section on mechanism, the substituent R is a substituent present in the terphenylene or quaterphenylene skeleton at a site where the HOMO is widely spread. If a sterically bulky substituent is present here, the bond between the phenylene rings or between the phenylene and the iridium atom will be significantly twisted, breaking the HOMO conjugation and significantly impairing the hole transport property, thereby preventing the effects of the present invention from being exhibited. Therefore, the substituent R is a hydrogen atom, D, or F.

[0055] <Substituent R 1 > Substituent R 1 is a substituent present at a substitution position that does not cause the above-mentioned HOMO twist, and is selected from the following substituent group W. However, since non-aromatic substituents have the effect of electrically insulating the iridium complex compound, if they are too large they may reduce the hole transport property of the iridium complex compound. The number of carbon atoms is limited to a level at which this effect is not apparent.

[0056] <Substituent group W> a hydrogen atom, D, F, Cl, Br, I, -N(R')2, -CN, -NO2, -OH, -COOR', -C(=O)R', -C(=O)NR', -P(=O)(R')2, -S(=O)R', -S(=O)2R', -OS(=O)2R', a linear, branched, or cyclic alkyl group having from 1 to 6 carbon atoms, a linear, branched, or cyclic alkoxy group having from 1 to 4 carbon atoms, a linear, branched, or cyclic alkylthio group having from 1 to 4 carbon atoms, a linear, branched, or cyclic alkenyl group having from 2 to 4 carbon atoms, a linear, branched, or cyclic alkynyl group having from 2 to 4 carbon atoms, an aromatic group having from 5 to 60 carbon atoms, a heteroaromatic group having from 5 to 60 carbon atoms, a diarylamino group having from 10 to 40 carbon atoms, an arylheteroarylamino group having from 10 to 40 carbon atoms, and a diheteroarylamino group having from 10 to 40 carbon atoms.

[0057] The alkyl group, the alkoxy group, the alkylthio group, the alkenyl group, the alkynyl group, the aromatic group, the heteroaromatic group, the diarylamino group, the arylheteroarylamino group and the diheteroarylamino group may be further substituted with one or more R' other than a hydrogen atom.

[0058] R' will be described later.

[0059] Each of the substituents in the above substituent group W will be explained below.

[0060] Examples of linear, branched, or cyclic alkyl groups having from 1 to 6 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, n-pentyl, n-hexyl, isopropyl, isobutyl, cyclopentyl, and cyclohexyl groups. In the case of alkyl groups, a large number of carbon atoms can result in a high degree of shielding of the iridium complex, resulting in a loss of durability. Therefore, the number of carbon atoms is preferably 1 or more, and is preferably 5 or less, and more preferably 4 or less.

[0061] Examples of the linear, branched, or cyclic alkoxy group having from 1 to 4 carbon atoms include a methoxy group, an ethoxy group, an n-propyloxy group, an n-butoxy group, etc. From the viewpoint of durability, the number of carbon atoms is preferably 1 or more, and is preferably 3 or less, more preferably 2 or less, and most preferably 1.

[0062] Examples of the linear, branched, or cyclic alkylthio group having from 1 to 4 carbon atoms include a methylthio group, an ethylthio group, an n-propylthio group, an n-butylthio group, an isopropylthio group, etc. From the viewpoint of durability, the number of carbon atoms is preferably 1 or more, and is preferably 3 or less, more preferably 2 or less, and most preferably 1.

[0063] Examples of the linear or branched alkenyl group having 2 to 4 carbon atoms include a vinyl group, an allyl group, a propenyl group, a butadiene group, etc. From the viewpoint of durability, the number of carbon atoms is preferably 2 or more and 3 or less, and 2 is most preferred.

[0064] Examples of the linear or branched alkynyl group having 2 to 4 carbon atoms include an ethynyl group, a propionyl group, a butynyl group, etc. From the viewpoint of durability, the number of carbon atoms is preferably 2 or more and preferably 3 or less, with 2 being most preferred.

[0065] The aromatic group having from 5 to 60 carbon atoms and the heteroaromatic group having from 5 to 60 carbon atoms may exist as a single ring or a condensed ring, or may be a group formed by further bonding or condensing another type of aromatic group or heteroaromatic group to one ring. Examples of these include a phenyl group, a naphthyl group, anthracenyl group, a benzanthracenyl group, a phenanthrenyl group, a benzophenanthrenyl group, a pyrenyl group, a chrysenyl group, a fluoranthenyl group, a perylenyl group, a benzopyrenyl group, a benzofluoranthenyl group, a naphthacenyl group, a pentacenyl group, a biphenyl group, a terphenyl group, a quaterphenyl group, a quinquephenyl group, a fluorenyl group, a spirobifluorenyl group, a dihydrophenanthrenyl group, a dihydropyrenyl group, a tetrahydropyrenyl group, an indenofluorenyl group, a furyl group, a benzofuryl group, an isobenzofuryl group, a dibenzofuranyl group, a thiophene group, a benzothiophenyl group, a dibenzothiophenyl group, a pyrrolyl group, an indolyl group, an isoindolyl group, a carbazolyl group, a benzocarbazolyl group, an indolocarbazolyl group, an indenocarbazolyl group, a pyridyl group, a cinnolyl group, and an isocinnolyl group. , acridyl group, phenanthridyl group, phenothiazinyl group, phenoxazyl group, pyrazolyl group, indazolyl group, imidazolyl group, benzimidazolyl group, naphthimidazolyl group, phenanthroimidazolyl group, pyridineimidazolyl group, oxazolyl group, benzoxazolyl group, naphthoxazolyl group, thiazolyl group, benzothiazolyl group, pyrimidyl group, benzopyrimidyl group, pyridazinyl group, quinoxalinyl group, diazaa Examples thereof include anthracenyl group, diazapyrenyl group, pyrazinyl group, phenoxazinyl group, phenothiazinyl group, naphthyridinyl group, azacarbazolyl group, benzocarbolinyl group, phenanthrolinyl group, triazolyl group, benzotriazolyl group, oxadiazolyl group, thiadiazolyl group, triazinyl group, 2,6-diphenyl-1,3,5-triazin-4-yl group, tetrazolyl group, purinyl group, and benzothiadiazolyl group.

[0066] From the viewpoint of the balance between solubility and durability, preferred are phenyl, naphthyl, phenanthrenyl, biphenyl, terphenyl, quaterphenyl, quinquephenyl, carbazolyl, indolocarbazolyl, indenocarbazolyl, pyridyl, pyrimidyl, and triazinyl groups, more preferred are phenyl, biphenyl, terphenyl, quaterphenyl, quinquephenyl, and pyridyl groups, and most preferred are phenyl, biphenyl, terphenyl, and quaterphenyl groups. From the viewpoint of the balance between solubility and durability, the number of carbon atoms in these groups is preferably 5 or more, and is preferably 50 or less, more preferably 40 or less, and most preferably 30 or less.

[0067] Examples of diarylamino groups having 10 to 40 carbon atoms include a diphenylamino group, a phenyl(naphthyl)amino group, a di(biphenyl)amino group, a di(p-terphenyl)amino group, etc. From the viewpoint of the balance between solubility and durability, the number of carbon atoms in these diarylamino groups is preferably 10 or more, and is preferably 36 or less, more preferably 30 or less, and most preferably 25 or less.

[0068] Examples of the arylheteroarylamino group having from 10 to 40 carbon atoms include a phenyl(2-pyridyl)amino group, a phenyl(2,6-diphenyl-1,3,5-triazin-4-yl)amino group, etc. From the viewpoint of the balance between solubility and durability, the number of carbon atoms in these arylheteroarylamino groups is preferably 10 or more, and is preferably 36 or less, more preferably 30 or less, and most preferably 25 or less.

[0069] Examples of diheteroarylamino groups having 10 to 40 carbon atoms include a di(2-pyridyl)amino group and a di(2,6-diphenyl-1,3,5-triazin-4-yl)amino group. From the viewpoint of the balance between solubility and durability, the number of carbon atoms in these diheteroarylamino groups is preferably 10 or more, and is preferably 36 or less, more preferably 30 or less, and most preferably 25 or less.

[0070] More preferred substituents R 1 In particular, from the viewpoint of not impairing the durability as a light-emitting material in an organic electroluminescent device, the substituents R each independently include a hydrogen atom, D, F, -CN, a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, an aromatic group having 5 to 60 carbon atoms, and a heteroaromatic group having 5 to 60 carbon atoms. 1 is particularly preferably D, F, -CN, an aromatic group or a heteroaromatic group. 1 is most preferably a hydrogen atom or D.

[0071] <R’> The R's are each independently selected from the following substituent group W'.

[0072] <Substituent group W'> A hydrogen atom, D, F, -CN, a linear, branched, or cyclic alkyl group having from 1 to 6 carbon atoms, a linear or branched alkenyl group having from 2 to 4 carbon atoms, or a linear or branched alkynyl group having from 2 to 4 carbon atoms.

[0073] Examples of the linear, branched, or cyclic alkyl group having from 1 to 6 carbon atoms, the linear or branched alkenyl group having from 2 to 4 carbon atoms, and the linear or branched alkynyl group having from 2 to 4 carbon atoms include the linear, branched, or cyclic alkyl group, linear or branched alkenyl group, and linear or branched alkynyl group exemplified in Substituent Group W.

[0074] <ar> Ar in the formula (1) has a structure represented by the formula (2). The substituents R and R of the benzene ring in the formula (2) 1 The types of the substituents R and R in formula (1) are 1 The types are similar. The benzene rings in formula (2) include the terminal benzene rings in formula (2), the m number of benzene rings, and the benzene rings bonded to the terminals of the n number of benzene rings in formula (1). In this specification, the terminal benzene ring in formula (2) is referred to as a "benzene ring (terminal)," the m number of benzene rings is referred to as a "benzene ring (m)," and the benzene ring bonded to the terminal of the n number of benzene rings in formula (1) is referred to as a "benzene ring (base end)," and these are collectively referred to as a "benzene ring in formula (2)."

[0075] <m> In formula (2), m teeth, m is an integer of n+1 to n+5. From the viewpoint of durability, m is preferably an integer of n+1 to n+4, and more preferably m is an integer of n+1 to n+3.

[0076] <Example> Preferred specific examples of the iridium complex compound of the present invention are shown below, but the iridium complex compound of the present invention is not limited to these.

[0077] [ka]

[0078] The maximum emission wavelength of the iridium complex compound of the present invention is not particularly limited, and can be measured, for example, by the following method. (Method for measuring maximum emission wavelength in solution) The iridium complex compound was dissolved in toluene at room temperature at a concentration of 1 x 10 -4 The phosphorescence spectrum of the solution dissolved at a concentration of 0.1 mol / L or less is measured using a spectrophotometer (organic electroluminescence quantum yield measurement system C9920-02 manufactured by Hamamatsu Photonics K.K.) The wavelength showing the maximum intensity of the obtained phosphorescence spectrum is regarded as the maximum emission wavelength in the present invention.

[0079] <Method for synthesizing iridium complex compounds> The ligands of the iridium complex compounds of this invention can be produced by converting building blocks such as bromopyridine, 2-(3-bromophenyl)pyridine, and 1-bromo-3-iodopyridine into boric acid esters via the Miyaura-Ishiyama borylation reaction or the Hartwig-Miyaura CH borylation reaction, and then constructing the skeleton via the Suzuki-Miyaura coupling reaction of these intermediates with aryl halides. By combining these with other known methods, ligands with various substituents can be synthesized.

[0080] Examples of methods for synthesizing iridium complex compounds include a method that uses a phenylpyridine ligand as an example for clarity, and that starts with a chlorine-bridged iridium dinuclear complex as shown in the following formula [A] (M.G. Colombo, T.C. Brunold, T.Riedener, H.U. Gudel, Inorg. Chem., 1994, 33, 545-550), and a method that converts a dinuclear complex as shown in the following formula [B] by exchanging the chlorine bridge with an acetylacetonate ligand to convert it into a mononuclear complex, and then obtains the target compound (S. Lamansky, P. Djurovich, D. Murphy, F. Abdel-Razzaq, R. Kwong, I. Tsyba, M. Borz, B. Mui, R. Bau, M. Thompson, Inorg. Chem., 2001, 40, 1704-1711). Another example is a method in which a ligand and a tris(acetylacetonato)iridium(III) complex are reacted in glycerin at high temperature to directly obtain a homo-triscyclometallated iridium complex (K. Dedeian, PI Djurovich, FO Garces, G. Carlson, RJ Watts, Inorg. Chem., 1991, 30, 1685-1687). The synthesis method for the iridium complex compound of the present invention is not limited to these.

[0081] The typical reaction conditions for the reaction represented by formula [A] are as follows: In the first step, a chlorine-bridged iridium dinuclear complex is synthesized by reacting two equivalents of a ligand with one equivalent of iridium chloride n-hydrate. A mixture of 2-ethoxyethanol and water is usually used as the solvent, but no solvent or other solvents may be used. The reaction can also be accelerated by using an excess amount of the ligand or by using an additive such as a base. Other bridging anionic ligands, such as bromine, can also be used instead of chlorine.

[0082] There are no particular limitations on the reaction temperature, but it is usually preferably 0° C. or higher, more preferably 50° C. or higher, and preferably 250° C. or lower, more preferably 150° C. or lower. Within these ranges, only the target reaction proceeds without the occurrence of by-products or decomposition reactions, and high selectivity tends to be obtained.

[0083] [ka]

[0084] In the second step, a halide ion scavenger such as silver trifluoromethanesulfonate is added and brought into contact with the newly added ligand to obtain the desired complex. Ethoxyethanol or diglyme is typically used as the solvent. Depending on the type of ligand, the reaction can proceed without a solvent or with a mixture of solvents. The addition of a halide ion scavenger is not always necessary, as the reaction may proceed without it. However, the addition of such a scavenger is advantageous for increasing the reaction yield and selectively synthesizing a facial isomer with a higher quantum yield. The reaction temperature is not particularly limited, but is typically in the range of 0°C to 250°C.

[0085] Typical reaction conditions represented by formula [B] are described below. The dinuclear complex in the first step can be synthesized in the same manner as formula [A]. In the second step, the dinuclear complex is converted into a mononuclear complex with a 1,3-dionato ligand by reacting it with at least one equivalent of a 1,3-dione compound such as acetylacetone and at least one equivalent of a basic compound capable of abstracting the active hydrogen of the 1,3-dione compound, such as sodium carbonate. A solvent such as ethoxyethanol or dichloromethane that can dissolve the starting dinuclear complex is usually used, but if the ligand is liquid, the reaction can be carried out without a solvent. There are no particular limitations on the reaction temperature, but it is usually within the range of 0°C to 200°C.

[0086] [ka]

[0087] In the third step, one or more equivalents of the ligand are reacted. There are no particular restrictions on the type or amount of solvent, and if the ligand is liquid at the reaction temperature, no solvent is necessary. There are also no particular restrictions on the reaction temperature, but because the reactivity is somewhat poor, the reaction is often carried out at relatively high temperatures of 100°C to 300°C. Therefore, a solvent with a high boiling point, such as glycerin, is preferably used.

[0088] After the final reaction, purification is carried out to remove unreacted raw materials, reaction by-products, and solvents. While purification procedures commonly used in organic synthetic chemistry can be applied, as described in the above-mentioned non-patent document, purification is primarily carried out by normal-phase silica gel column chromatography. The developing solution can be a single or mixed solution of hexane, heptane, dichloromethane, chloroform, ethyl acetate, toluene, methyl ethyl ketone, or methanol. Purification may be carried out multiple times under different conditions. Other chromatographic techniques (reverse-phase silica gel chromatography, size exclusion chromatography, paper chromatography), as well as purification procedures such as separation washing, reprecipitation, recrystallization, powder suspension washing, and vacuum drying, can also be used as needed.

[0089] <Uses of iridium complex compounds> The iridium complex compound of the present invention can be suitably used as a material for use in organic electroluminescent devices, i.e., as a red light-emitting material for organic electroluminescent devices, and can also be suitably used as a light-emitting material for organic electroluminescent devices and other light-emitting devices.

[0090] [Iridium complex compound-containing composition] The iridium complex compound of the present invention has excellent solvent solubility, and is therefore preferably used together with a solvent. Hereinafter, a composition containing the iridium complex compound of the present invention and a solvent (hereinafter, sometimes referred to as the "iridium complex compound-containing composition of the present invention" or simply as the "iridium complex compound-containing composition") will be described.

[0091] The iridium complex compound-containing composition of the present invention contains the iridium complex compound of the present invention described above and a solvent. Furthermore, the iridium complex compound-containing composition of the present invention may contain one or more iridium complex compounds represented by formula (3) described below. The iridium complex compound-containing composition of the present invention is typically used to form a layer or film by a wet film-forming method. It is particularly preferred to use it to form an organic layer of an organic electroluminescent device. The organic layer is preferably a light-emitting layer. In other words, the iridium complex compound-containing composition is preferably a composition for organic electroluminescent devices, and is particularly preferably used as a composition for forming a light-emitting layer.

[0092] The content of the iridium complex compound of the present invention in the iridium complex compound-containing composition is usually 0.001% by mass or more, preferably 0.01% by mass or more, and usually 99.9% by mass or less, preferably 99% by mass or less. By setting the content of the iridium complex compound in the composition within this range, holes and electrons can be efficiently injected from adjacent layers (e.g., hole transport layer or hole blocking layer) into the light-emitting layer, thereby reducing the driving voltage. The iridium complex compound-containing composition may contain only one type of iridium complex compound of the present invention, or two or more types may be contained in combination.

[0093] When the iridium complex compound-containing composition of the present invention contains the iridium complex compound of the present invention represented by the above formula (1) and an iridium complex compound as another luminescent material represented by the below-described formula (3), it is preferable that these iridium complex compounds are contained in such a way that the total amount of these iridium complex compounds satisfies the above-mentioned iridium complex compound content. In order to effectively obtain the effects of the present invention obtained by containing the iridium complex compound of the present invention represented by formula (1) above, and the effects described below by containing an iridium complex compound as another luminescent material represented by formula (3) described below, the content of the iridium complex compound of the present invention represented by formula (1) above in a total of 100% by mass of these iridium complex compounds is preferably 10% by mass or more, particularly 20% by mass or more, and is preferably 90% by mass or less.

[0094] When the iridium complex compound-containing composition of the present invention is used for, for example, an organic electroluminescent device, it may contain, in addition to the above-mentioned iridium complex compound and solvent, a charge transport compound used in the organic electroluminescent device, particularly in the light-emitting layer. When the iridium complex compound-containing composition of the present invention is used to form a light-emitting layer of an organic electroluminescent device, it is preferable that the iridium complex compound of the present invention is used as a light-emitting material and another charge-transporting compound is contained as a charge-transporting host material.

[0095] The solvent contained in the iridium complex compound-containing composition of the present invention is a volatile liquid component used to form a layer containing an iridium complex compound by wet film formation. The solvent is not particularly limited as long as it is an organic solvent in which the charge transporting compound described below dissolves well, since the iridium complex compound of the present invention, which is the solute, has high solvent solubility. Preferred solvents include, for example, alkanes such as n-decane, cyclohexane, ethylcyclohexane, decalin, and bicyclohexane; aromatic hydrocarbons such as toluene, xylene, mesitylene, phenylcyclohexane, and tetralin; halogenated aromatic hydrocarbons such as chlorobenzene, dichlorobenzene, and trichlorobenzene; and aromatic ethers such as 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole, and diphenyl ether. aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate; alicyclic ketones such as cyclohexanone, cyclooctanone, and fenchone; alicyclic alcohols such as cyclohexanol and cyclooctanol; aliphatic ketones such as methyl ethyl ketone and dibutyl ketone; aliphatic alcohols such as butanol and hexanol; and aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA).

[0096] Among these, alkanes and aromatic hydrocarbons are preferred, and phenylcyclohexane in particular has a viscosity and boiling point that are suitable for the wet film-forming process.

[0097] These solvents may be used alone or in any combination of two or more in any ratio.

[0098] The boiling point of the solvent used is usually 80° C. or higher, preferably 100° C. or higher, more preferably 120° C. or higher, and usually 270° C. or lower, preferably 250° C. or lower, more preferably 230° C. or lower. If the boiling point is below this range, evaporation of the solvent from the composition during wet film formation may result in a decrease in film formation stability.

[0099] The content of the solvent in the iridium complex compound-containing composition is preferably 1% by mass or more, more preferably 10% by mass or more, particularly preferably 50% by mass or more, and preferably 99.99% by mass or less, more preferably 99.9% by mass or less, particularly preferably 99% by mass or less. The thickness of the light-emitting layer is usually about 3 to 200 nm, but if the solvent content is below this lower limit, the viscosity of the composition may become too high, potentially reducing the film-forming workability. On the other hand, if the solvent content exceeds this upper limit, the film obtained by removing the solvent after film formation cannot be thick enough, which tends to make film formation difficult.

[0100] Other charge-transporting compounds that may be contained in the iridium complex compound-containing composition of the present invention include those conventionally used as materials for organic electroluminescent devices. Examples include pyridine, carbazole, naphthalene, perylene, pyrene, anthracene, chrysene, naphthacene, phenanthrene, coronene, fluoranthene, benzophenanthrene, fluorene, acetonaphthofluoranthene, coumarin, p-bis(2-phenylethenyl)benzene and derivatives thereof, quinacridone derivatives, DCM (4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran)-based compounds, benzopyran derivatives, rhodamine derivatives, benzothioxanthene derivatives, azabenzothioxanthene, fused aromatic ring compounds substituted with an arylamino group, and styryl derivatives substituted with an arylamino group.

[0101] These may be used alone or in any combination and ratio of two or more.

[0102] Furthermore, the content of other charge transport compounds in the iridium complex compound-containing composition is usually 1,000 parts by mass or less, preferably 100 parts by mass or less, and more preferably 50 parts by mass or less, relative to 1 part by mass of the iridium complex compound of the present invention in the iridium complex compound-containing composition, and is usually 0.01 part by mass or more, preferably 0.1 part by mass or more, and more preferably 1 part by mass or more.

[0103] The iridium complex compound-containing composition of the present invention may contain, as necessary, other compounds in addition to the above-mentioned compounds. For example, in addition to the above-mentioned solvents, another solvent may be contained. Examples of such solvents include amides such as N,N-dimethylformamide and N,N-dimethylacetamide, and dimethyl sulfoxide. These may be used alone or in any combination and ratio of two or more.

[0104] [Organic electroluminescent device] An organic electroluminescent device using the iridium complex compound of the present invention (hereinafter, sometimes referred to as "organic electroluminescent device of the present invention") will be described below. The organic electroluminescent device of the present invention contains the iridium complex compound of the present invention. The organic electroluminescent device of the present invention preferably has at least an anode, a cathode, and at least one organic layer between the anode and the cathode on a substrate, and at least one of the organic layers contains the iridium complex compound of the present invention. The organic layer includes a light-emitting layer.

[0105] The organic layer containing the iridium complex compound of the present invention is more preferably a layer formed using the iridium complex compound-containing composition of the present invention, and even more preferably a layer formed by a wet film-forming method. The layer formed by the wet film-forming method is preferably the light-emitting layer.

[0106] (Wet film formation method) The wet film formation method is a method in which a composition containing a solvent is applied onto a substrate, and then the solvent is removed to form a film. Examples of the application method include wet film formation methods such as spin coating, dip coating, die coating, bar coating, blade coating, roll coating, spray coating, capillary coating, inkjet printing, nozzle printing, screen printing, gravure printing, and flexographic printing. The film formed by these methods is dried to form a film.

[0107] As a method for removing the solvent after coating, reduced pressure and / or heating can be used. The method of removing the solvent by reduced pressure is also called vacuum drying. Vacuum drying is a method in which the substrate coated with the composition is placed in a vacuum chamber and the pressure is reduced to remove the solvent. The method of removing the solvent by heating is also called heat drying. As a heating means used in heat drying, a clean oven or a hot plate is preferred because it applies heat evenly to the entire film.

[0108] The heating temperature in the heat drying may be any temperature as long as it does not significantly impair the effects of the present invention. A higher temperature is preferable in terms of shortening the drying time, while a lower temperature is preferable in terms of minimizing damage to the material. The upper limit of the heating temperature is usually 250°C or less, preferably 200°C or less, and more preferably 150°C or less. The lower limit of the heating temperature is usually 30°C or more, preferably 50°C or more, and more preferably 80°C or more. Temperatures exceeding the upper limit are undesirable because they exceed the heat resistance of commonly used charge transport materials or phosphorescent materials, which may lead to decomposition or crystallization. Temperatures below the lower limit are undesirable because they require a long time to remove the solvent. The heating time in the heating step is appropriately determined based on the boiling point and vapor pressure of the solvent in the composition, the heat resistance of the materials, and the heating conditions.

[0109] Either one of vacuum drying and heat drying may be performed, or both may be performed. Heat drying is preferred because it is easier to remove the solvent. Furthermore, it is preferable to reduce the amount of solvent contained in the coating film by vacuum drying before heat drying, because this can suppress the influence of retention and make it easier to form a flat and uniform film.

[0110] Fig. 1 is a schematic cross-sectional view showing an example of a structure suitable for an organic electroluminescent element 10 of the present invention. In Fig. 1, reference numeral 1 represents a substrate, reference numeral 2 represents an anode, reference numeral 3 represents a hole injection layer, reference numeral 4 represents a hole transport layer, reference numeral 5 represents a light-emitting layer, reference numeral 6 represents a hole blocking layer, reference numeral 7 represents an electron transport layer, reference numeral 8 represents an electron injection layer, and reference numeral 9 represents a cathode.

[0111] The materials used in these structures are not particularly limited and may be known materials. Representative materials and manufacturing methods for each layer are described below as examples. When publications, papers, etc. are cited, the relevant content is deemed to be applicable and adaptable as appropriate within the scope of common sense of a person skilled in the art.

[0112] <Board 1> The substrate 1 serves as a support for the organic electroluminescent element, and is typically made of a quartz or glass plate, a metal plate or metal foil, a plastic film or sheet, or the like. Of these, a glass plate or a plate made of a transparent synthetic resin such as polyester, polymethacrylate, polycarbonate, or polysulfone is preferred. The substrate 1 is preferably made of a material with high gas barrier properties, as this makes it less likely for the organic electroluminescent element to deteriorate due to the outside air. Therefore, when using a material with low gas barrier properties, such as a synthetic resin substrate, it is preferable to provide a dense silicon oxide film or the like on at least one side of the substrate 1 to improve the gas barrier properties.

[0113] <Anode 2> The anode 2 has the function of injecting holes into the layer on the light-emitting layer side. The anode 2 is usually made of a metal such as aluminum, gold, silver, nickel, palladium, or platinum; a metal oxide such as indium and / or tin oxide; a metal halide such as copper iodide; or a conductive polymer such as carbon black, poly(3-methylthiophene), polypyrrole, or polyaniline.

[0114] The anode 2 is usually formed by a dry method such as sputtering or vacuum deposition. When the anode 2 is formed using metal fine particles such as silver, fine particles such as copper iodide, carbon black, conductive metal oxide fine particles, conductive polymer fine powder, or the like, the anode 2 can be formed by dispersing the material in an appropriate binder resin solution and applying it to the substrate. In the case of a conductive polymer, the anode 2 can be formed by forming a thin film directly on the substrate by electrolytic polymerization, or by applying the conductive polymer to the substrate (Appl. Phys. Lett., Vol. 60, p. 2711, 1992).

[0115] The anode 2 usually has a single layer structure, but may have a laminated structure as appropriate. When the anode 2 has a laminated structure, a different conductive material may be laminated on the first layer of the anode.

[0116] The thickness of the anode 2 may be determined depending on the required transparency, material, etc. When particularly high transparency is required, a thickness that provides a visible light transmittance of 60% or more is preferred, and a thickness that provides a visible light transmittance of 80% or more is even more preferred. The thickness of the anode 2 is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably 500 nm or less. When transparency is not required, the thickness of the anode 2 may be arbitrarily determined depending on the required strength, etc. In this case, the anode 2 may have the same thickness as the substrate 1.

[0117] When forming a film on the surface of the anode 2, it is preferable to perform a treatment with ultraviolet light and ozone, oxygen plasma, argon plasma, or the like before the film formation to remove impurities on the anode and adjust its ionization potential to improve hole injection properties.

[0118] <Hole injection layer 3> A layer that transports holes from the anode 2 side to the light-emitting layer 5 side is usually called a hole injection transport layer or hole transport layer. When there are two or more layers that transport holes from the anode 2 side to the light-emitting layer 5 side, the layer closer to the anode 2 side may be called the hole injection layer 3. The hole injection layer 3 is preferably used in order to enhance the function of transporting holes from the anode 2 to the light-emitting layer 5 side. When the hole injection layer 3 is used, the hole injection layer 3 is usually formed on the anode 2.

[0119] The thickness of the hole injection layer 3 is usually 1 nm or more, preferably 5 nm or more, and usually 1000 nm or less, preferably 500 nm or less.

[0120] The hole injection layer 3 may be formed by vacuum deposition or wet film formation, but is preferably formed by wet film formation in terms of excellent film formability.

[0121] The hole injection layer 3 preferably contains a hole transport compound, more preferably contains a hole transport compound and an electron acceptor compound, and further preferably contains a cation radical compound, particularly preferably contains a cation radical compound and a hole transport compound.

[0122] (Hole transporting compound) The hole injection layer-forming composition typically contains a hole transport compound that will become the hole injection layer 3. In the case of a wet film formation method, it typically also contains a solvent. The hole injection layer-forming composition preferably has high hole transport properties and can efficiently transport injected holes. For this reason, it is preferable that the hole injection layer-forming composition has high hole mobility and is less likely to generate impurities that become traps during production or use. It is also preferable that the composition has excellent stability, a small ionization potential, and high transparency to visible light. In particular, when the hole injection layer 3 is in contact with the light-emitting layer 5, it is preferable that the composition does not quench the emission from the light-emitting layer 5 or that does not form exciplexes with the light-emitting layer 5 and thereby reduce the luminous efficiency.

[0123] The hole transporting compound is preferably a compound having an ionization potential of 4.5 eV to 6.0 eV from the viewpoint of the charge injection barrier from the anode 2 to the hole injection layer 3. Examples of the hole transporting compound include aromatic amine compounds, phthalocyanine compounds, porphyrin compounds, oligothiophene compounds, polythiophene compounds, benzylphenyl compounds, compounds in which a tertiary amine is linked via a fluorene group, hydrazone compounds, silazane compounds, and quinacridone compounds.

[0124] Among the above-mentioned exemplary compounds, aromatic amine compounds are preferred, and aromatic tertiary amine compounds are particularly preferred, from the viewpoints of amorphousness and visible light transmittance. The aromatic tertiary amine compounds are compounds having an aromatic tertiary amine structure and also include compounds having a group derived from an aromatic tertiary amine.

[0125] The type of aromatic tertiary amine compound is not particularly limited, but it is preferable to use a polymer compound (polymerized compound having a series of repeating units) having a weight average molecular weight of 1,000 to 1,000,000, in terms of easily obtaining uniform light emission due to the surface smoothing effect. Preferred examples of aromatic tertiary amine polymer compounds include polymer compounds having a repeating unit represented by the following formula (I):

[0126] [ka]

[0127] (In formula (I), Ar 1 and Ar 2 each independently represents an aromatic group which may have a substituent or a heteroaromatic group which may have a substituent. Ar 3 ~Ar 5 each independently represents an aromatic group which may have a substituent or a heteroaromatic group which may have a substituent. Q represents a linking group selected from the group of linking groups shown below. Ar 1 ~Ar 5 Two groups bonded to the same N atom may be bonded to each other to form a ring.

[0128] The linking groups are shown below.

[0129] [ka]

[0130] (In each of the above formulas, Ar 6 ~Ar 16 R each independently represents an aromatic group which may have a substituent or a heteroaromatic group which may have a substituent. a ~R b each independently represents a hydrogen atom or an arbitrary substituent.

[0131] Ar 1 ~Ar 16 As the aromatic group and heteroaromatic group, from the viewpoints of the solubility, heat resistance, and hole injection and transport properties of the polymer compound, groups derived from a benzene ring, a naphthalene ring, a phenanthrene ring, a thiophene ring, and a pyridine ring are preferred, and groups derived from a benzene ring and a naphthalene ring are more preferred.

[0132] Specific examples of aromatic tertiary amine polymer compounds having a repeating unit represented by formula (I) include those described in WO 2005 / 089024.

[0133] (Electron-accepting compounds) The hole injection layer 3 preferably contains an electron accepting compound, since the conductivity of the hole injection layer 3 can be improved by oxidation of the hole transporting compound.

[0134] The electron-accepting compound is preferably a compound having oxidizing power and the ability to accept one electron from the hole-transporting compound. Specifically, a compound having an electron affinity of 4 eV or more is preferred, and a compound having an electron affinity of 5 eV or more is more preferred.

[0135] Examples of such electron-accepting compounds include one or more compounds selected from the group consisting of triarylboron compounds, metal halides, Lewis acids, organic acids, onium salts, salts of arylamines and metal halides, and salts of arylamines and Lewis acids. Specific examples include organically substituted onium salts such as 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate and triphenylsulfonium tetrafluoroborate (WO 2005 / 089024), high-valent inorganic compounds such as iron(III) chloride (JP 11-251067 A) and ammonium peroxodisulfate, cyano compounds such as tetracyanoethylene, aromatic boron compounds such as tris(pentafluorophenyl)borane (JP 2003-31365 A), fullerene derivatives, and iodine.

[0136] (cation radical compound) The cation radical compound is preferably an ionic compound consisting of a cation radical, which is a chemical species obtained by removing one electron from a hole-transporting compound, and a counter anion. However, when the cation radical is derived from a hole-transporting polymer compound, the cation radical has a structure in which one electron is removed from the repeating unit of the polymer compound.

[0137] The cation radical is preferably a chemical species obtained by removing one electron from the compound described above as a hole transport compound, which is preferable in terms of amorphousness, visible light transmittance, heat resistance, solubility, etc. The cation radical compound can be produced by mixing the hole transport compound and the electron acceptor compound. That is, by mixing the hole transport compound and the electron acceptor compound, electrons are transferred from the hole transport compound to the electron acceptor compound, and a cation ion compound consisting of the cation radical of the hole transport compound and a counter anion is produced.

[0138] Cation radical compounds derived from polymeric compounds such as PEDOT / PSS (Adv. Mater., 2000, Vol. 12, p. 481) and emeraldine hydrochloride (J. Phys. Chem., 1990, Vol. 94, p. 7716) can also be produced by oxidative polymerization (dehydrogenative polymerization). The oxidative polymerization referred to here is a process in which a monomer is chemically or electrochemically oxidized in an acidic solution using peroxodisulfate or the like. In this oxidative polymerization (dehydrogenative polymerization), the monomer is oxidized to form a polymer, and a cation radical is generated by removing one electron from the repeating unit of the polymer, with the anion derived from the acidic solution as the counter anion.

[0139] (Formation of Hole Injection Layer 3 by Wet Film Formation Method) When the hole injection layer 3 is formed by a wet film formation method, a film formation composition (hole injection layer formation composition) is usually prepared by mixing the material for the hole injection layer 3 with a soluble solvent (hole injection layer solvent), and this hole injection layer formation composition is formed into a film on a layer corresponding to the layer below the hole injection layer 3 (usually the anode 2) by a wet film formation method, followed by drying. The formed film can be dried in the same manner as in the formation of the light emitting layer 5 by a wet film formation method.

[0140] The concentration of the hole transport compound in the composition for forming a hole injection layer may be any concentration as long as it does not significantly impair the effects of the present invention, but a lower concentration is preferable in terms of uniformity of the film thickness, while a higher concentration is preferable in terms of reducing the likelihood of defects in the hole injection layer 3. Specifically, the concentration is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and particularly preferably 0.5% by mass or more, and is preferably 70% by mass or less, more preferably 60% by mass or less, and particularly preferably 50% by mass or less.

[0141] Examples of the solvent include ether-based solvents, ester-based solvents, aromatic hydrocarbon-based solvents, and amide-based solvents.

[0142] Examples of ether solvents include aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA), and aromatic ethers such as 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, and 2,4-dimethylanisole.

[0143] Examples of the ester solvent include aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate. Examples of aromatic hydrocarbon solvents include toluene, xylene, cyclohexylbenzene, 3-isopropylbiphenyl, 1,2,3,4-tetramethylbenzene, 1,4-diisopropylbenzene, and methylnaphthalene. Examples of the amide solvent include N,N-dimethylformamide and N,N-dimethylacetamide. In addition to these, dimethyl sulfoxide and the like can also be used.

[0144] The hole injection layer 3 is usually formed by a wet film formation method by preparing a composition for forming the hole injection layer, applying the composition to a layer (usually the anode 2) that corresponds to the layer below the hole injection layer 3, and then drying the applied film. After forming the hole injection layer 3, the applied film is usually dried by heating, drying under reduced pressure, or the like.

[0145] (Formation of Hole Injection Layer 3 by Vacuum Vapor Deposition) When forming the hole injection layer 3 by vacuum deposition, one or more of the constituent materials of the hole injection layer 3 (such as the hole transport compound and electron acceptor compound) are usually placed in a crucible installed in a vacuum chamber (when two or more materials are used, they are usually placed in separate crucibles), and the vacuum chamber is evacuated by a vacuum pump for 10 -4 After evacuating the chamber to about 100 Pa, the crucible is heated (when two or more materials are used, each crucible is usually heated), and the materials in the crucible are evaporated while controlling the evaporation rate (when two or more materials are used, each material is usually evaporated while controlling the evaporation rate independently), to form a hole injection layer 3 on the anode 2 on the substrate placed opposite the crucible. When two or more materials are used, a mixture of the materials can also be placed in the crucible, heated, and evaporated to form the hole injection layer 3.

[0146] The degree of vacuum during deposition is not limited as long as it does not significantly impair the effects of the present invention. -6 Torr (0.13 × 10 -4 Pa) or above, 9.0×10 -6 Torr (12.0 × 10 -4 The deposition rate is not limited as long as it does not significantly impair the effects of the present invention, but is usually 0.1 Å / sec or more and 5.0 Å / sec or less. The film formation temperature during deposition is not limited as long as it does not significantly impair the effects of the present invention, but is preferably 10°C or more and 50°C or less.

[0147] <Hole transport layer 4> The hole transport layer 4 is a layer that transports holes from the anode 2 side to the light-emitting layer 5 side. The hole transport layer 4 is not an essential layer in the organic electroluminescent device of the present invention, but it is preferable to provide this layer in order to enhance the function of transporting holes from the anode 2 to the light-emitting layer 5. When the hole transport layer 4 is provided, it is usually formed between the anode 2 and the light-emitting layer 5. When the above-mentioned hole injection layer 3 is present, the hole transport layer 4 is formed between the hole injection layer 3 and the light-emitting layer 5.

[0148] The thickness of the hole transport layer 4 is usually 5 nm or more, preferably 10 nm or more, and usually 300 nm or less, preferably 100 nm or less.

[0149] The hole transport layer 4 may be formed by vacuum deposition or wet film formation, but is preferably formed by wet film formation in terms of excellent film formability.

[0150] The hole transport layer 4 usually contains a hole transport compound. Examples of the hole transport compound contained in the hole transport layer 4 include aromatic diamines containing two or more tertiary amines and having two or more condensed aromatic rings substituted with nitrogen atoms, such as 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (JP-A-5-234681), and aromatic amine compounds having a starburst structure, such as 4,4',4''-tris(1-naphthylphenylamino)triphenylamine (J. Lumin. , vol. 72-74, p. 985, 1997), aromatic amine compounds consisting of triphenylamine tetramers (Chem. Commun., p. 2175, 1996), spiro compounds such as 2,2',7,7'-tetrakis-(diphenylamino)-9,9'-spirobifluorene (Synth. Metals, vol. 91, p. 209, 1997), and carbazole derivatives such as 4,4'-N,N'-dicarbazolebiphenyl. Furthermore, for example, polyvinylcarbazole, polyvinyltriphenylamine (JP-A-7-53953), and polyarylene ether sulfones containing tetraphenylbenzidine (Polym. Adv. Tech., vol. 7, p. 33, 1996) can also be preferably used.

[0151] (Formation of Hole Transport Layer 4 by Wet Film Formation Method) When the hole transport layer 4 is formed by a wet film formation method, it is usually formed using a composition for forming a hole transport layer instead of the composition for forming a hole injection layer, in the same manner as when the hole injection layer 3 described above is formed by a wet film formation method.

[0152] When the hole transport layer 4 is formed by a wet film formation method, the composition for forming a hole transport layer usually further contains a solvent. The solvent used in the composition for forming a hole transport layer can be the same as the solvent used in the composition for forming a hole injection layer described above. The concentration of the hole transporting compound in the composition for forming a hole transport layer can be set to the same range as the concentration of the hole transporting compound in the composition for forming a hole injection layer. The hole transport layer 4 can be formed by a wet film formation method similar to the film formation method for the hole injection layer 3 described above.

[0153] (Formation of Hole Transport Layer 4 by Vacuum Vapor Deposition) When forming the hole transport layer 4 by vacuum deposition, it can be formed in the same manner as when forming the hole injection layer 3 by vacuum deposition, using the material of the hole transport layer 4 instead of the material of the hole injection layer 3. The film formation conditions, such as the degree of vacuum, deposition rate, and temperature during deposition, can be the same as those used for vacuum deposition of the hole injection layer 3.

[0154] <Light-emitting layer 5> The light-emitting layer 5 is a layer that is excited by the recombination of holes injected from the anode 2 and electrons injected from the cathode 9 when an electric field is applied between the pair of electrodes, and thus emits light. The light-emitting layer 5 is a layer formed between the anode 2 and the cathode 9. When the hole injection layer 3 is present on the anode 2, the light-emitting layer 5 is formed between the hole injection layer 3 and the cathode 9. When the hole transport layer 4 is present on the anode 2, the light-emitting layer 5 is formed between the hole transport layer 4 and the cathode 9.

[0155] The thickness of the light-emitting layer 5 is arbitrary as long as it does not significantly impair the effects of the present invention, but a thicker layer is preferable in terms of preventing defects from occurring in the film, while a thinner layer is preferable in terms of facilitating a low driving voltage. Therefore, the thickness of the light-emitting layer 5 is preferably 3 nm or more, more preferably 5 nm or more, and usually preferably 200 nm or less, more preferably 100 nm or less.

[0156] The light-emitting layer 5 contains at least a material having light-emitting properties (light-emitting material), and preferably contains a material having charge-transport properties (charge-transporting material). As the light-emitting material, any of the light-emitting layers may contain the iridium complex compound of the present invention, and other light-emitting materials may also be used as appropriate. The light-emitting layer may contain two or more types of the iridium complex compound of the present invention. Light-emitting materials other than the iridium complex compound of the present invention will be described in detail below.

[0157] (luminescent material) The light-emitting material is not particularly limited as long as it emits light at a desired emission wavelength and does not impair the effects of the present invention, and any known light-emitting material can be used. The light-emitting material may be a fluorescent material or a phosphorescent material, but a material with good luminous efficiency is preferred. From the viewpoint of internal quantum efficiency, a phosphorescent material is preferred.

[0158] Examples of fluorescent materials include the following materials: Examples of fluorescent light-emitting materials that emit blue light (blue fluorescent light-emitting materials) include naphthalene, perylene, pyrene, anthracene, coumarin, chrysene, p-bis(2-phenylethenyl)benzene, and derivatives thereof. Examples of fluorescent materials that emit green light (green fluorescent materials) include quinacridone derivatives, coumarin derivatives, and aluminum complexes such as Al(C9H6NO)3. Examples of fluorescent materials that emit yellow light (yellow fluorescent materials) include rubrene and perimidon derivatives. Examples of fluorescent materials that emit red light (red fluorescent materials) include DCM (4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran) compounds, benzopyran derivatives, rhodamine derivatives, benzothioxanthene derivatives, and azabenzothioxanthene.

[0159] Examples of phosphorescent materials include organometallic complexes containing a metal selected from Groups 7 to 11 of the long periodic table (hereinafter, unless otherwise specified, the term "periodic table" refers to the long periodic table). Preferred examples of metals selected from Groups 7 to 11 of the periodic table include ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, and gold.

[0160] As the ligand of the organometallic complex, a ligand in which a (hetero)aryl group is linked to pyridine, pyrazole, phenanthroline, etc., such as a (hetero)arylpyridine ligand or a (hetero)arylpyrazole ligand, is preferred, and a phenylpyridine ligand or a phenylpyrazole ligand is particularly preferred. Here, (hetero)aryl represents an aryl group or a heteroaryl group.

[0161] Specific examples of preferred phosphorescent materials include phenylpyridine complexes such as tris(2-phenylpyridine)iridium, tris(2-phenylpyridine)ruthenium, tris(2-phenylpyridine)palladium, bis(2-phenylpyridine)platinum, tris(2-phenylpyridine)osmium, and tris(2-phenylpyridine)rhenium; and porphyrin complexes such as octaethylplatinum porphyrin, octaphenylplatinum porphyrin, octaethylpalladium porphyrin, and octaphenylpalladium porphyrin.

[0162] A particularly preferred material as another light-emitting material is an iridium complex compound represented by the following formula (3). By appropriately selecting the substituents, the iridium complex compound represented by the following formula (3) can reduce the effect on the emission wavelength and chromaticity of an organic EL device, and at the same time, can suppress aggregation of the iridium complex compound during the drying process of the light-emitting layer-forming composition (corresponding to the iridium complex compound-containing composition of the present invention) applied when forming the light-emitting layer, thereby preventing a decrease in device performance. Furthermore, an improvement in the dissolution stability of the light-emitting layer-forming composition, i.e., an effect of preventing reprecipitation during long-term storage, can also be expected.

[0163] [ka]

[0164] [In formula (3), Ir represents an iridium atom, and Ar has the structure represented by formula (2).]

[0165] The substituents R and R in formula (3) 1 The types and preferred ranges of are the same as those in the above formula (1). Ar has the same meaning as in the above formula (2). In this case, m is an integer ranging from 1 to 6.

[0166] Specific examples of iridium complex compounds represented by formula (3) that are particularly preferred as other light-emitting materials are shown below.

[0167] [ka]

[0168] Examples of polymer-based light-emitting materials include polyfluorene-based materials such as poly(9,9-dioctylfluorene-2,7-diyl), poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl))diphenylamine)], and poly[(9,9-dioctylfluorene-2,7-diyl)-co-(1,4-benzo-2{2,1'-3}-triazole)], and polyphenylenevinylene-based materials such as poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene].

[0169] (charge transport material) The charge transporting material is a material that has the ability to transport positive charges (holes) or negative charges (electrons), and is not particularly limited as long as it does not impair the effects of the present invention, and known materials can be used. As the charge transporting material, compounds that have been used in the light-emitting layer 5 of organic electroluminescent devices can be used, and compounds that have been used as host materials for the light-emitting layer 5 are particularly preferred.

[0170] Specific examples of the charge transporting material include the compounds exemplified as the hole transporting compound for the hole injection layer 3, such as aromatic amine compounds, phthalocyanine compounds, porphyrin compounds, oligothiophene compounds, polythiophene compounds, benzylphenyl compounds, compounds in which a tertiary amine is linked via a fluorene group, hydrazone compounds, silazane compounds, silanamine compounds, phosphamine compounds, and quinacridone compounds, as well as electron transporting compounds such as anthracene compounds, pyrene compounds, carbazole compounds, pyridine compounds, phenanthroline compounds, oxadiazole compounds, and silole compounds.

[0171] Other examples of charge transporting materials include aromatic diamines containing two or more tertiary amines, such as 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl, in which two or more condensed aromatic rings are substituted with nitrogen atoms (JP-A-5-234681); aromatic amine compounds having a starburst structure, such as 4,4',4''-tris(1-naphthylphenylamino)triphenylamine (J. Lumin., vol. 72-74, p. 985, 1997); triphenylamines; Compounds exemplified as hole-transporting compounds for the hole-transport layer 4, such as aromatic amine compounds consisting of a tetramer of diphenylamine (Chem. Commun., p. 2175, 1996), fluorene compounds such as 2,2',7,7'-tetrakis-(diphenylamino)-9,9'-spirobifluorene (Synth. Metals, vol. 91, p. 209, 1997), and carbazole compounds such as 4,4'-N,N'-dicarbazolebiphenyl, can also be preferably used. Other examples include oxadiazole compounds such as 2-(4-biphenylyl)-5-(p-tert-butylphenyl)-1,3,4-oxadiazole (tBu-PBD) and 2,5-bis(1-naphthyl)-1,3,4-oxadiazole (BND); silole compounds such as 2,5-bis(6'-(2',2"-bipyridyl))-1,1-dimethyl-3,4-diphenylsilole (PyPySPyPy); and phenanthroline compounds such as bathophenanthroline (BPhen) and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP, bathocuproine).

[0172] (Formation of light-emitting layer 5 by wet film formation method) The light-emitting layer 5 may be formed by vacuum deposition or wet film formation, but the wet film formation is preferred due to its superior film-forming properties.

[0173] When the light-emitting layer 5 is formed by a wet film-forming method, it is usually formed using a composition for forming a light-emitting layer prepared by mixing a material for the light-emitting layer 5 with a soluble solvent (solvent for the light-emitting layer) instead of the composition for forming a hole-injection layer, in the same manner as when the hole-injection layer 3 described above is formed by a wet film-forming method. In the present invention, it is preferable to use the iridium complex compound-containing composition of the present invention described above as the composition for forming the light-emitting layer.

[0174] Examples of the solvent include the ether-based solvents, ester-based solvents, aromatic hydrocarbon-based solvents, and amide-based solvents mentioned for forming the hole injection layer 3, as well as alkane-based solvents and halogenated aromatic hydrocarbon-based solvents. Basic Examples of solvents include ethanol-based solvents, aliphatic alcohol-based solvents, alicyclic alcohol-based solvents, aliphatic ketone-based solvents, and alicyclic ketone-based solvents. The solvents used are the same as those exemplified as solvents for the iridium complex compound-containing composition of the present invention. Specific examples of solvents are listed below, but are not limited to these as long as they do not impair the effects of the present invention.

[0175] For example, aliphatic ether solvents such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA); aromatic ether solvents such as 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole, and diphenyl ether; aromatic ester solvents such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate; toluene, xylene, mesitylene, cyclohexylbenzene, tetralin, and 3-isopropyl biphenyl. Examples of suitable solvents include aromatic hydrocarbon solvents such as phenyl, 1,2,3,4-tetramethylbenzene, 1,4-diisopropylbenzene, and methylnaphthalene; amide solvents such as N,N-dimethylformamide and N,N-dimethylacetamide; alkane solvents such as n-decane, cyclohexane, ethylcyclohexane, decalin, and bicyclohexane; halogenated aromatic hydrocarbon solvents such as chlorobenzene, dichlorobenzene, and trichlorobenzene; aliphatic alcohol solvents such as butanol and hexanol; alicyclic alcohol solvents such as cyclohexanol and cyclooctanol; aliphatic ketone solvents such as methyl ethyl ketone and dibutyl ketone; and alicyclic ketone solvents such as cyclohexanone, cyclooctanone, and fenchone. Among these, alkane solvents and aromatic hydrocarbon solvents are particularly preferred.

[0176] To obtain a more uniform film, it is preferable that the solvent evaporates at an appropriate rate from the liquid film immediately after film formation. Therefore, as described above, the boiling point of the solvent used is usually 80°C or higher, preferably 100°C or higher, more preferably 120°C or higher, and usually 270°C or lower, preferably 250°C or lower, more preferably 230°C or lower.

[0177] The amount of solvent used is arbitrary as long as it does not significantly impair the effects of the present invention. The total content of solvent in the composition for forming a light-emitting layer, i.e., the iridium complex compound-containing composition, is preferably high because it has low viscosity and therefore facilitates film formation, while being low because it facilitates the formation of a thick film. As mentioned above, the content of solvent in the iridium complex compound-containing composition is preferably 1% by mass or more, more preferably 10% by mass or more, particularly preferably 50% by mass or more, and preferably 99.99% by mass or less, more preferably 99.9% by mass or less, particularly preferably 99% by mass or less.

[0178] The solvent can be removed after the wet film formation by heating or reducing pressure. In the heating method, a clean oven or a hot plate is preferred as the heating means to apply heat uniformly to the entire film.

[0179] The heating temperature in the heating step may be any temperature as long as it does not significantly impair the effects of the present invention. However, a higher temperature is preferable in terms of shortening the drying time, and a lower temperature is preferable in terms of minimizing damage to the material. The upper limit of the heating temperature is usually 250°C or less, preferably 200°C or less, and more preferably 150°C or less. The lower limit of the heating temperature is usually 30°C or more, preferably 50°C or more, and more preferably 80°C or more. Temperatures exceeding the upper limit are not preferred because they exceed the heat resistance of commonly used charge transport materials or phosphorescent materials and may cause decomposition or crystallization. Temperatures below the lower limit are not preferred because they require a long time to remove the solvent. The heating time in the heating step is appropriately determined based on the boiling point and vapor pressure of the solvent in the composition for forming an emitting layer, the heat resistance of the material, and the heating conditions.

[0180] (Formation of the light-emitting layer 5 by vacuum deposition method) When forming the light-emitting layer 5 by vacuum deposition, one or more of the constituent materials of the light-emitting layer 5 (such as the above-mentioned light-emitting material and charge-transporting compound) are usually placed in a crucible installed in a vacuum chamber (when two or more materials are used, each is usually placed in a separate crucible), and the vacuum chamber is evacuated by a vacuum pump for 10 -4 After evacuating the chamber to about 100 Pa, the crucible is heated (when two or more materials are used, each crucible is usually heated), and the materials in the crucible are evaporated while controlling the amount of evaporation (when two or more materials are used, each material is usually evaporated while controlling the amount of evaporation independently), to form the light-emitting layer 5 on the hole injection layer 3 or hole transport layer 4 placed opposite the crucible. When two or more materials are used, the light-emitting layer 5 can also be formed by placing a mixture of these materials in the crucible and heating and evaporating them.

[0181] The degree of vacuum during deposition is not limited as long as it does not significantly impair the effects of the present invention. -6 Torr (0.13 × 10 -4 Pa) or above, 9.0×10 -6 Torr (12.0 × 10 -4 The deposition rate is not limited as long as it does not significantly impair the effects of the present invention, but is usually 0.1 Å / sec or more and 5.0 Å / sec or less. The film formation temperature during deposition is not limited as long as it does not significantly impair the effects of the present invention, but is preferably 10°C or more and 50°C or less.

[0182] <Hole-blocking layer 6> A hole-blocking layer 6 may be provided between the light-emitting layer 5 and the electron-injecting layer 8 described below. The hole-blocking layer 6 is a layer laminated on the light-emitting layer 5 so as to be in contact with the interface of the light-emitting layer 5 on the cathode 9 side.

[0183] The hole blocking layer 6 has the role of preventing holes migrating from the anode 2 from reaching the cathode 9 and the role of efficiently transporting electrons injected from the cathode 9 toward the light-emitting layer 5 . The properties required for the material constituting the hole blocking layer 6 include high electron mobility and low hole mobility, a large energy gap (difference between HOMO and LUMO), and a high excited triplet level (T1).

[0184] Examples of materials for the hole-blocking layer 6 that satisfy these conditions include mixed ligand complexes such as bis(2-methyl-8-quinolinolato)(phenolato)aluminum and bis(2-methyl-8-quinolinolato)(triphenylsilanolato)aluminum; metal complexes such as bis(2-methyl-8-quinolinolato)aluminum-μ-oxo-bis-(2-methyl-8-quinolinolato)aluminum binuclear metal complex; styryl compounds such as distyrylbiphenyl derivatives (Japanese Patent Laid-Open No. 11-242996); triazole derivatives such as 3-(4-biphenylyl)-4-phenyl-5(4-tert-butylphenyl)-1,2,4-triazole (Japanese Patent Laid-Open No. 7-41759); and phenanthroline derivatives such as bathocuproine (Japanese Patent Laid-Open No. 10-79297). Furthermore, compounds having at least one pyridine ring substituted at the 2-, 4-, and 6-positions, as described in WO 2005 / 022962, are also preferred as materials for the hole-blocking layer 6.

[0185] There is no limitation on the method for forming the hole blocking layer 6, and it can be formed in the same manner as the method for forming the light emitting layer 5 described above. The thickness of the hole blocking layer 6 is arbitrary as long as it does not significantly impair the effects of the present invention, but is usually 0.3 nm or more, preferably 0.5 nm or more, and usually 100 nm or less, preferably 50 nm or less.

[0186] <Electron transport layer 7> The electron transport layer 7 is formed by transferring electrons from the light-emitting layer 5 or the hole transport layer 6 to the light-emitting layer 5 in order to further improve the current efficiency of the device. prevention It is provided between layer 6 and electron injection layer 8 . The electron transport layer 7 is formed from a compound that can efficiently transport electrons injected from the cathode 9 between electrodes to which an electric field is applied, toward the light-emitting layer 5. The electron transporting compound used in the electron transport layer 7 is required to have a high efficiency of electron injection from the cathode 9 or the electron injection layer 8, and to have high electron mobility so that the injected electrons can be efficiently transported.

[0187] Specific examples of electron transport compounds that satisfy these conditions include metal complexes such as aluminum complexes of 8-hydroxyquinoline (Japanese Patent Laid-Open No. 194393 / 1984), metal complexes of 10-hydroxybenzo[h]quinoline, oxadiazole derivatives, distyrylbiphenyl derivatives, silole derivatives, 3-hydroxyflavone metal complexes, 5-hydroxyflavone metal complexes, benzoxazole metal complexes, benzothiazole metal complexes, trisbenzimidazolylbenzene (U.S. Pat. No. 5,645,948), quinoxaline compounds (Japanese Patent Laid-Open No. 207169 / 1994), phenanthroline derivatives (Japanese Patent Laid-Open No. 331459 / 1993), 2-t-butyl-9,10-N,N'-dicyanoanthraquinone diimine, n-type hydrogenated amorphous silicon carbide, n-type zinc sulfide, and n-type zinc selenide.

[0188] The thickness of the electron transport layer 7 is usually 1 nm or more, preferably 5 nm or more, and usually 300 nm or less, preferably 100 nm or less. The electron transport layer 7 is formed by laminating it on the light emitting layer 5 or the hole blocking layer 6 by a wet film formation method or a vacuum deposition method, similar to the light emitting layer 5. Usually, the vacuum deposition method is used.

[0189] <Electron injection layer 8> The electron injection layer 8 plays a role of efficiently injecting electrons injected from the cathode 9 into the electron transport layer 7 or the light-emitting layer 5 . To efficiently inject electrons, a metal with a low work function is preferable for the material forming the electron injection layer 8. Examples include alkali metals such as sodium and cesium, and alkaline earth metals such as barium and calcium. The thickness of the electron injection layer 8 is preferably 0.1 to 5 nm.

[0190] Inserting an ultrathin insulating film (with a film thickness of about 0.1 to 5 nm) made of LiF, MgF2, Li2O, Cs2CO3, or the like as an electron injection layer 8 at the interface between the cathode 9 and the electron transport layer 7 is also an effective method for improving the efficiency of the device (Appl. Phys. Lett., Vol. 70, p. 152, 1997; JP-A-10-74586; IEEE Trans. Electron. Devices, Vol. 44, p. 1245, 1997; SID 04 Digest, p. 154).

[0191] Organic electron-transporting materials, such as nitrogen-containing heterocyclic compounds such as bathophenanthroline or metal complexes such as aluminum complexes of 8-hydroxyquinoline, are preferably doped with alkali metals such as sodium, potassium, cesium, lithium, or rubidium (as described in JP-A Nos. 10-270171, 2002-100478, and 2002-100482). This improves electron injection and transport properties and provides excellent film quality. In this case, the film thickness is typically 5 nm or more, preferably 10 nm or more, and typically 200 nm or less, preferably 100 nm or less.

[0192] The electron injection layer 8 is formed by laminating it on the light-emitting layer 5 or the hole blocking layer 6 or electron transport layer 7 thereon by a wet film-forming method or a vacuum deposition method in the same manner as the light-emitting layer 5. The details of the wet film formation method are the same as those of the light-emitting layer 5 described above.

[0193] <Cathode 9> The cathode 9 serves to inject electrons into the layer on the light-emitting layer 5 side (such as the electron injection layer 8 or the light-emitting layer 5). The cathode 9 can be made of any of the materials used for the anode 2, but for efficient electron injection, it is preferable to use a metal with a low work function, such as tin, magnesium, indium, calcium, aluminum, silver, or an alloy thereof. Specific examples include low-work-function alloy electrodes such as a magnesium-silver alloy, a magnesium-indium alloy, or an aluminum-lithium alloy.

[0194] From the viewpoint of device stability, it is preferable to protect the cathode 9 made of a metal having a low work function by laminating a metal layer having a high work function and being stable against the atmosphere on the cathode 9. Examples of the metal to be laminated include aluminum, silver, copper, nickel, chromium, gold, and platinum. The thickness of the cathode is usually the same as that of the anode 2 .

[0195] <Other constituent layers> 1 has been mainly described, the organic electroluminescent device of the present invention may have any layer between the anode 2 and cathode 9 and the light-emitting layer 5 in addition to the layers described above, as long as the performance is not impaired. Any layer other than the light-emitting layer 5 may also be omitted.

[0196] For example, a hole blocking layer 6 For the same purpose, it is also effective to provide an electron blocking layer between the hole transport layer 4 and the light emitting layer 5. The electron blocking layer prevents electrons moving from the light emitting layer 5 from reaching the hole transport layer 4, thereby increasing the probability of recombination with holes in the light emitting layer 5 and trapping the generated excitons within the light emitting layer 5, and also efficiently transporting holes injected from the hole transport layer 4 toward the light emitting layer 5.

[0197] The properties required for the electron blocking layer include high hole transportability, a large energy gap (difference between HOMO and LUMO), and a high excited triplet level (T1). When the light-emitting layer 5 is formed by a wet film-forming method, it is preferable to also form the electron-blocking layer by a wet film-forming method, since this facilitates device production. Therefore, it is preferable that the electron blocking layer also has compatibility with wet film formation. Materials used for such electron blocking layers include copolymers of dioctylfluorene and triphenylamine, such as F8-TFB (WO 2004 / 084260).

[0198] 1, it is also possible to laminate the cathode 9, electron injection layer 8, electron transport layer 7, hole blocking layer 6, light-emitting layer 5, hole transport layer 4, hole injection layer 3, and anode 2 in this order on substrate 1. The organic electroluminescent device of the present invention can also be provided between two substrates, at least one of which is highly transparent. It is also possible to create a structure in which multiple layers of the layer configuration shown in Figure 1 are stacked (a structure in which multiple light-emitting units are stacked). In this case, using, for example, V2O5 as a charge generation layer instead of the interfacial layer between the layers (between the light-emitting units) (when the anode is ITO and the cathode is Al, these two layers) reduces the barrier between the layers, which is preferable from the standpoints of luminous efficiency and driving voltage.

[0199] The present invention can be applied to any organic electroluminescent device, whether it is a single device, a device with a structure in which the devices are arranged in an array, or a structure in which the anodes and cathodes are arranged in an XY matrix.

[0200] [Display and lighting devices] A display device (hereinafter referred to as "the display device of the present invention") and a lighting device (hereinafter referred to as "the lighting device of the present invention") can be manufactured using the organic electroluminescent device of the present invention as described above. There are no particular limitations on the type or structure of the display device and lighting device of the present invention, and they can be assembled in accordance with a conventional method using the organic electroluminescent device of the present invention. For example, the display device and lighting device of the present invention can be formed by a method such as that described in "Organic EL Display" (Ohmsha, published August 20, 2004, by Tokito Shizuo, Adachi Chinaya, and Murata Hideyuki). [Example]

[0201] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples, and the present invention can be practiced with any modifications without departing from the gist of the present invention. In the following synthesis examples, all reactions were carried out under a nitrogen stream. Solvents and solutions used in the reactions were degassed by an appropriate method such as nitrogen bubbling.

[0202] [Synthesis of Iridium Complex Compounds] <Synthesis Example 1: Synthesis of Compound (D-1)> [ka]

[0203] 3-(2-pyridyl)phenylboronic acid pinacol ester (7.32 g), 3-bromo-4'-iodo-1,1'-biphenyl (9.45 g), tetrakis(triphenylphosphine)palladium(0) (0.62 g), 2M aqueous potassium phosphate (35 mL), toluene (50 mL), and ethanol (35 mL) were placed in a 300 mL recovery flask and refluxed for 8 hours. After cooling to room temperature, the aqueous phase was removed, and the solvent was removed under reduced pressure. The resulting residue was purified by silica gel column chromatography (dichloromethane / hexane = 1 / 1 to 1 / 0) to give 9.95 g of intermediate 1 as a brown amorphous solid.

[0204] [ka]

[0205] Intermediate 1 (28.7 g), bis-pinacolatodiboron (23.7 g), potassium acetate (36.9 g), [Pd(dppf)2Cl2]CHCl2 (1.84 g), and dimethyl sulfoxide (250 mL) were placed in a 1 L recovery flask and stirred in a 90 °C oil bath for 3 h. After cooling to room temperature, water (0.5 L) and dichloromethane (0.3 L) were added for separation and washing. After drying over magnesium sulfate, the solvent was removed under reduced pressure. The resulting residue was purified by silica gel column chromatography (ethyl acetate / hexane = 1 / 9 to 15 / 85) to yield Intermediate 2 (30.1 g) as a pale yellow solid.

[0206] [ka]

[0207] Intermediate 2 (30.1 g), 3-bromo-3'-iodo-1,1'-biphenyl (27.5 g), tetrakis(triphenylphosphine)palladium(0) (1.06 g), 2M aqueous potassium phosphate (90 mL), toluene (300 mL), and ethanol (90 mL) were placed in a 1 L recovery flask and refluxed for 4 hours. After cooling to room temperature, the aqueous phase was removed and the solvent was removed under reduced pressure. The resulting residue was purified by silica gel column chromatography (dichloromethane / hexane = 1 / 1 to 7 / 3), yielding 35.8 g of intermediate 3 as a cream-colored amorphous solid.

[0208] [ka]

[0209] A 300 mL recovery flask was charged with intermediate 3 (15.3 g), m-biphenylboronic acid (7.2 g), tetrakis(triphenylphosphine)palladium(0) (1.25 g), 2 M aqueous potassium phosphate (45 mL), toluene (80 mL), and ethanol (45 mL), and the mixture was refluxed and stirred for 5 hours. After cooling to room temperature, the aqueous phase was removed, and the solvent was removed under reduced pressure. The residue was purified by silica gel column chromatography (dichloromethane / hexane = 1 / 1 to 1 / 0), yielding 18.2 g of ligand 1 as a white amorphous solid.

[0210] [ka]

[0211] Ligand 1 (10.2 g), iridium(III) chloride n-hydrate (Furuya Metals, 2.76 g), water (25 mL), and 2-ethoxyethanol (125 mL) were placed in a 200 mL three-neck flask equipped with a Dimroth tube and stirred in an oil bath at 140 °C while the solvent was removed by distillation. After 2.5 hours, diglyme (40 mL) was added, and the oil bath was heated to 150 °C. After another 2 hours, 2-ethoxyethanol (35 mL) was added, and the oil bath was heated to 155 °C. After another 4 hours, a solution of ethyldiisopropylamine (1.5 mL) in diglyme (2.5 mL) was added, and after another 1 hour, a solution of ethyldiisopropylamine (1.5 mL) in diglyme (2.5 mL) was added, and the mixture was stirred for another 2 hours. The volume of liquid distilled off during the reaction was 140 mL. After cooling to room temperature, the solvent was removed under reduced pressure and the resulting residue was purified by silica gel column chromatography (dichloromethane / hexane = 4 / 6 to 3 / 7), yielding 6.7 g of binuclear complex 1 as a golden yellow amorphous substance.

[0212] [ka]

[0213] Dinuclear complex 1 (6.7 g), ligand 1 (8.0 g), and diglyme (20 mL) were placed in a 200 mL recovery flask and stirred in an oil bath at 135 °C until dissolved. Then, silver trifluoromethanesulfonate (1.21 g) was added, and the temperature of the oil bath was increased to 140 °C and stirred for 1.5 hours. The solvent was then removed under reduced pressure, and the resulting residue was purified by silica gel column chromatography (dichloromethane / hexane = 1 / 1), yielding 7.7 g of compound (D-1) as a yellow solid.

[0214] <Synthesis Example 2: Synthesis of Compound (D-2)> [ka]

[0215] Intermediate 1 (10.0 g), [(1,1':3',1''-terphenyl)-3-yl]boronic acid (10.6 g), tetrakis(triphenylphosphine)palladium(0) (0.68 g), 2M aqueous potassium phosphate (35 mL), toluene (65 mL), and ethanol (35 mL) were placed in a 1 L recovery flask and refluxed with stirring for 5 hours. After cooling to room temperature, the aqueous phase was removed, and the solvent was removed under reduced pressure. The resulting residue was purified by silica gel column chromatography (dichloromethane / hexane = 7 / 3 to 1 / 0) to yield 12.2 g of Ligand 2 as a white amorphous solid.

[0216] [ka]

[0217] Ligand 2 (12.2 g), tris(acetylacetonato)iridium(III) (2.6 g), and glycerin (15.4 g) were placed in a 100 mL recovery flask equipped with a Dimroth tube and stirred in an oil bath at 240 °C for 7 hours. After cooling to room temperature, water (100 mL) and dichloromethane (100 mL) were added and the mixture was separated. The oil phase was dried over magnesium sulfate. After filtration, the solvent was removed under reduced pressure. The resulting residue was purified by silica gel column chromatography (dichloromethane / hexane = 1 / 1), yielding 2.75 g of compound (D-2) as a yellow solid.

[0218] <Synthesis Example 3: Synthesis of Compound (D-8)> [ka]

[0219] A 1-L recovery flask was charged with 2,6-dimethylphenylboronic acid (20.8 g), 1-bromo-3-iodobenzene (37.5 g), tetrakis(triphenylphosphine)palladium(0) (5.4 g), barium hydroxide octahydrate (62.9 g), water (150 mL), and 1,2-dimethoxyethane (400 mL), and the mixture was refluxed and stirred in an oil bath at 110°C for 3.5 hours. After cooling to room temperature, the aqueous phase was removed, and the solvent was removed under reduced pressure. The resulting residue was purified by silica gel column chromatography (dichloromethane / hexane = 1 / 200), yielding 29.2 g of 3-bromo-2',6'-dimethylbiphenyl as a colorless oil.

[0220] [ka]

[0221] A 1-L recovery flask was charged with 3-bromo-2',6'-dimethylbiphenyl (29.1 g), bispinacolatodiboron (34.8 g), potassium acetate (54.5 g), [Pd(dppf)2Cl2]CHCl2 (2.9 g), and 1,4-dioxane (300 mL) and stirred in an oil bath at 90 °C for 4.5 h. After cooling to room temperature, the solvent was removed under reduced pressure. The resulting residue was purified by silica gel column chromatography (ethyl acetate / hexane = 1 / 9) to yield 2-(2',6'-dimethyl[1,1'-biphenyl]-3-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (31.1 g) as a white solid.

[0222] [ka]

[0223] A 100 mL recovery flask was charged with intermediate 3 (4.1 g), 2-(2',6'-dimethyl[1,1'-biphenyl]-3-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2.5 g), tetrakis(triphenylphosphine)palladium(0) (0.44 g), 2 M aqueous potassium phosphate (11 mL), toluene (24 mL), and ethanol (12 mL). The mixture was refluxed in an oil bath at 95 °C for 14 h. After cooling to room temperature, the aqueous phase was removed, and the solvent was removed under reduced pressure. The resulting residue was purified by silica gel column chromatography (ethyl acetate / hexane = 1 / 4 to 1 / 3) to yield 4.3 g of ligand 3 as a white amorphous solid.

[0224] [ka]

[0225] Ligand 3 (3.9 g), tris(acetylacetonato)iridium(III) (0.75 g), and glycerin (4.6 g) were placed in a 100 mL recovery flask equipped with a Dimroth tube and stirred in an oil bath at 240 °C for 8 hours. After cooling to room temperature, water (30 mL) and dichloromethane (50 mL) were added and the mixture was separated. The oil phase was dried over magnesium sulfate. After filtration, the solvent was removed under reduced pressure. The resulting residue was purified by silica gel column chromatography (dichloromethane / hexane = 1 / 1), yielding 0.75 g of compound (D-8) as a yellow solid.

[0226] <Synthesis Example 4: Synthesis of Compound (D-9)> [ka]

[0227] Intermediate 3 (4.8 g), 4-tert-butylphenylboronic acid (1.7 g), tetrakis(triphenylphosphine)palladium(0) (0.51 g), 2M aqueous potassium phosphate solution (13 mL), toluene (28 mL), and ethanol (14 mL) were placed in a 100 mL recovery flask and refluxed in an oil bath at 95°C for 8.5 hours. After cooling to room temperature, the aqueous phase was removed, and the solvent was removed under reduced pressure. The resulting residue was purified by silica gel column chromatography (ethyl acetate / hexane = 1 / 4) to yield 3.8 g of ligand 4 as a white amorphous solid.

[0228] [ka]

[0229] Ligand 4 (3.8 g), tris(acetylacetonato)iridium(III) (0.78 g), and glycerin (4.5 g) were placed in a 100 mL recovery flask equipped with a Dimroth tube and stirred in an oil bath at 240 °C for 9 hours. After cooling to room temperature, water (30 mL) and dichloromethane (50 mL) were added and the mixture was separated. The oil phase was dried over magnesium sulfate. After filtration, the solvent was removed under reduced pressure. The resulting residue was purified by silica gel column chromatography (dichloromethane / hexane = 1 / 1), yielding 1.11 g of compound (D-9) as a yellow solid.

[0230] [Fabrication and Performance Evaluation of Organic Electroluminescent Devices] [Example 1] An organic electroluminescent device was fabricated in the following manner. A 50-nm-thick indium tin oxide (ITO) transparent conductive film (Geomatec, sputter-deposited) was deposited on a glass substrate and patterned into 2-mm-wide stripes using standard photolithography and hydrochloric acid etching to form the anode. The substrate with the ITO pattern formed was then ultrasonically cleaned with a surfactant solution, rinsed with ultrapure water, ultrasonically cleaned with ultrapure water, and rinsed with ultrapure water again, followed by drying with compressed air and finally cleaning with ultraviolet ozone.

[0231] A composition for forming a hole injection layer was prepared by dissolving 3.0 mass% of a hole transporting polymer compound having a repeating structure of the following formula (P-1) and 0.6 mass% of an electron accepting compound (HI-1) in ethyl benzoate.

[0232] [ka]

[0233] This composition for forming a hole injection layer was spin-coated onto the substrate in the atmosphere and dried on a hot plate in the atmosphere at 240° C. for 30 minutes to form a uniform thin film with a thickness of 40 nm, which was used as a hole injection layer.

[0234] Next, a charge transporting polymer compound having the following structural formula (HT-1) was dissolved in 1,3,5-trimethylbenzene at a concentration of 2.0% by mass to prepare a composition for forming a hole transporting layer.

[0235] [ka]

[0236] This composition for forming a hole transport layer was spin-coated in a nitrogen glove box onto the substrate on which the hole injection layer had been coated, and dried on a hot plate in the nitrogen glove box at 230°C for 30 minutes to form a uniform thin film with a thickness of 40 nm, which served as the hole transport layer.

[0237] Subsequently, as materials for the light-emitting layer, 1.3 mass % of compound (H-1) having the following structure, 1.3 mass % of (H-2), 2.6 mass % of (H-3), and 1.56 mass % of compound (D-1) of the present invention were dissolved in cyclohexylbenzene to prepare a composition for forming the light-emitting layer.

[0238] [ka]

[0239] This composition for forming an emissive layer was spin-coated in a nitrogen glove box onto the substrate on which the hole transport layer had been coated, and dried on a hot plate in the nitrogen glove box at 120°C for 20 minutes to form a uniform thin film with a thickness of 40 nm, which served as the emissive layer.

[0240] The substrate on which the light-emitting layer had been formed was placed in a vacuum deposition device, and the inside of the device was heated to 2 × 10 -4 The pressure was evacuated until it reached a pressure of 0.1 Pa or less.

[0241] Next, the following structural formula (ET-1) and 8-hydroxyquinolinolatolithium were co-deposited on the light-emitting layer in a thickness ratio of 2:3 by vacuum deposition to form an electron transport layer with a thickness of 30 nm.

[0242] [ka]

[0243] Next, a 2 mm wide striped shadow mask was attached to the substrate as a mask for cathode deposition so that it was perpendicular to the ITO stripes of the anode, and aluminum was heated using a molybdenum boat to form an 80 nm thick aluminum layer, forming the cathode. In this manner, an organic electroluminescent device having a light-emitting area measuring 2 mm×2 mm was obtained.

[0244] [Example 2] An organic electroluminescent device was produced in the same manner as in Example 1, except that the compound (D-2) having the following structure was used instead of the compound (D-1) in preparing the composition for forming the light-emitting layer to form the light-emitting layer.

[0245] [ka]

[0246] [Comparative Example 1] An organic electroluminescent device was produced in the same manner as in Example 1, except that the compound (D-3) having the following structure was used instead of the compound (D-1) in preparing the composition for forming the light-emitting layer to form the light-emitting layer.

[0247] [ka]

[0248] Comparative Example 2 An organic electroluminescent device was produced in the same manner as in Example 1, except that the compound (D-4) having the following structure was used instead of the compound (D-1) in preparing the composition for forming the light-emitting layer to form the light-emitting layer.

[0249] [ka]

[0250] [Example 3] An organic electroluminescent device was produced in the same manner as in Example 1, except that the light-emitting layer was formed by using 0.39 mass % of the compound (D-6) and 1.17 mass % of the compound (D-1) instead of the compound (D-1) in preparing the composition for forming the light-emitting layer. The compound (D-6) was synthesized with reference to the method described in Japanese Patent Publication No. 2014-074000.

[0251] [ka]

[0252] [Example 4] An organic electroluminescent device was produced in the same manner as in Example 1, except that the composition for forming the light-emitting layer was prepared by using 0.78 mass% of the compound (D-6) and 0.78 mass% of the compound (D-1) instead of the compound (D-1).

[0253] Comparative Example 3 An organic electroluminescent device was produced in the same manner as in Example 1, except that the light-emitting layer was formed using compound (D-5) having the following structure instead of compound (D-1) in the preparation of the composition for forming the light-emitting layer. Compound (D-5) was synthesized with reference to the synthesis method of compound (D-1).

[0254] [ka]

[0255] Comparative Example 4 An organic electroluminescent device was produced in the same manner as in Example 1, except that the compound (D-6) was used instead of the compound (D-1) in preparing the composition for forming the light-emitting layer to form the light-emitting layer.

[0256] Comparative Example 5 An organic electroluminescent device was produced in the same manner as in Example 1, except that the light-emitting layer was formed using compound (D-7) having the following structure instead of compound (D-1) in the preparation of the composition for forming the light-emitting layer. Compound (D-7) was synthesized by the method described in Japanese Patent Publication No. 2014-074000.

[0257] [ka]

[0258] [Example 5] An organic electroluminescent device was produced in the same manner as in Example 1, except that the compound (D-8) was used instead of the compound (D-1) in preparing the composition for forming the light-emitting layer to form the light-emitting layer.

[0259] [ka]

[0260] [Example 6] An organic electroluminescent device was produced in the same manner as in Example 1, except that the compound (D-9) was used instead of the compound (D-1) in preparing the composition for forming the light-emitting layer to form the light-emitting layer.

[0261] [ka]

[0262] Comparative Example 6 In preparing the composition for forming the light-emitting layer, the light-emitting layer was formed using the compound (D-10) having the following structure instead of the compound (D-1). An organic electroluminescent device was produced in the same manner as in Example 1. The compound (D-10) was synthesized by the method described in Japanese Patent Publication No. 2021-138735.

[0263] [ka]

[0264] [Element evaluation] The organic electroluminescent devices obtained in Examples 1 to 6 and Comparative Examples 1 to 6 were measured at a luminance of 1,000 cd / m 2 The voltage (V) and external quantum efficiency (%) were measured when the device was lit at 15 mA / cm. 2 When a current was continuously applied to the element at a current density of 1000 kJ / s, the time (LT90) until the luminance decreased to 90% of the initial luminance was measured. The value obtained by subtracting the voltage of Comparative Example 1 from the voltage of Example 1 was defined as the relative voltage (V) of Example 1. The value obtained by dividing the external quantum efficiency of Example 1 by the external quantum efficiency of Comparative Example 1 was defined as the relative external quantum efficiency of Example 1. The value obtained by dividing the LT90 of Example 1 by the LT90 of Comparative Example 1 was defined as the relative drive life of Example 1. Similarly, the value obtained by subtracting the voltage of Comparative Example 1 from the voltage of Example 2 was taken as the relative voltage (V) of Example 2. The value obtained by dividing the external quantum efficiency of Example 2 by the external quantum efficiency of Comparative Example 1 was taken as the relative external quantum efficiency of Example 2. The value obtained by dividing the LT90 of Example 2 by the LT90 of Comparative Example 1 was taken as the relative drive life of Example 2. Similarly, the value obtained by subtracting the voltage of Comparative Example 1 from the voltage of Comparative Example 2 was taken as the relative voltage (V) of Comparative Example 2. The value obtained by dividing the external quantum efficiency of Comparative Example 2 by the external quantum efficiency of Comparative Example 1 was taken as the relative external quantum efficiency of Comparative Example 2. The value obtained by dividing the LT90 of Comparative Example 2 by the LT90 of Comparative Example 1 was taken as the relative drive life of Comparative Example 2. The same applies to Examples 3 to 6 and Comparative Examples 3 to 6 below. The results of these measurements are shown in Table 1.

[0265] [Table 1]

[0266] The results in Table 1 show that the organic electroluminescent device using the iridium complex compound of the present invention has improved performance. As is clear from the solubility test results below, compounds (D-1) and (D-2) can be dissolved in cyclohexylbenzene at the same concentration as compounds (D-3) and (D-4), and have excellent solvent solubility, just like compounds (D-3) and (D-4).

[0267] [Solubility test of iridium complex compounds] [Example 7] 3% by mass of compound (D-1) and 97% by mass of cyclohexylbenzene (abbreviated as CHB) were mixed in a brown glass vial and sealed with a cap. This was heated on a hot plate at 68°C until completely dissolved. After storing at room temperature and observing, it was found that no precipitation occurred and the mixture remained homogeneous even after 210 days.

[0268] [Example 8] 3% by mass of compound (D-2) and 97% by mass of cyclohexylbenzene were mixed in a brown glass vial and sealed with a cap. This was heated on a hot plate at 68°C until completely dissolved. After that, it was stored at room temperature and observed. After 310 days, no precipitation occurred and the mixture remained homogeneous.

[0269] [Example 9] A 1:3 mixture of 3% by mass of compound (D-1) and compound (D-6) and 97% by mass of cyclohexylbenzene were mixed in a brown glass vial and sealed with a cap. The mixture was heated on a hot plate at 68°C until completely dissolved. After storage at room temperature and observation, the mixture remained homogeneous without precipitation even after 336 days.

[0270] [Example 10] A 1:1 mixture of 3% by mass of compound (D-1) and compound (D-6) and 97% by mass of cyclohexylbenzene were mixed in a brown glass vial and sealed with a cap. The mixture was heated on a hot plate at 68°C until completely dissolved. After storage at room temperature and observation, the mixture remained homogeneous without precipitation even after 335 days.

[0271] [Example 11] A 3:1 mixture of 3% by mass of compound (D-1) and compound (D-6) and 97% by mass of cyclohexylbenzene were mixed in a brown glass vial and sealed with a cap. The mixture was heated on a hot plate at 68°C until completely dissolved. After storage at room temperature and observation, the mixture remained homogeneous without precipitation even after 336 days.

[0272] Comparative Example 7 3% by mass of compound (D-5) and 97% by mass of cyclohexylbenzene were mixed in a brown glass vial and sealed with a cap. This was heated on a hot plate at 100°C until it was completely dissolved. After storing it at room temperature, precipitation was confirmed after just 5 minutes.

[0273] The results of these tests are shown in Table 2.

[0274] [Table 2]

[0275] The results in Table 2 show that the iridium complex compound of the present invention has excellent solubility in solvents and can remain stable as ink for a long period of time without causing precipitation.

[0276] Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the invention. This application is based on Japanese Patent Application No. 2021-087775, filed on May 25, 2021, the entire contents of which are incorporated by reference. [Explanation of symbols]

[0277] 1 board 2 Anode 3. Hole injection layer 4. Hole transport layer 5. Light-emitting layer 6. Hole-blocking layer 7 Electron transport layer 8 Electron injection layer 9 Cathode 10 Organic electroluminescent device< / m> < / ar> < / n>

Claims

1. An iridium complex compound represented by the following formula (1): 【Chemical Formula 1】 In formula (1), Ir represents an iridium atom, n is 1 or 2, and Ar has a structure represented by the following formula (2): 【Chemistry 2】 In formula (2), the dashed line represents a bond to Ar in formula (1), and m is an integer of m=n+1 to n+5. The substituents R in formula (1) and formula (2) are each independently a hydrogen atom, D or F. Substituent R in formula (1) and formula (2) １ are each independently a hydrogen atom, D, F, Cl, Br, I, or —N(R′) ２ , -CN, -NO ２ , -OH, -COOR', -C(=O)R', -C(=O)NR', -P(=O)(R') ２ , -S(=O)R', -S(=O) ２ R', -OS(=O) ２ R' is a linear, branched, or cyclic alkyl group having from 1 to 6 carbon atoms, a linear, branched alkoxy group having from 1 to 4 carbon atoms, a linear, branched, or cyclic alkylthio group having from 1 to 4 carbon atoms, a linear or branched alkenyl group having from 2 to 4 carbon atoms, a linear or branched alkynyl group having from 2 to 4 carbon atoms, an aromatic group having from 5 to 60 carbon atoms, a heteroaromatic group having from 5 to 60 carbon atoms, a diarylamino group having from 10 to 40 carbon atoms, an arylheteroarylamino group having from 10 to 40 carbon atoms, or a diheteroarylamino group having from 10 to 40 carbon atoms. These groups may be substituted with one or more R' other than a hydrogen atom. Each R' is independently a hydrogen atom, D, F, -CN, a linear, branched, or cyclic alkyl group having from 1 to 6 carbon atoms, a linear or branched alkenyl group having from 2 to 4 carbon atoms, or a linear or branched alkynyl group having from 2 to 4 carbon atoms.

2. The substituents R and R in the formula (1) and the formula (2) １ The iridium complex compound according to claim 1 , wherein is a hydrogen atom or D.

3. An iridium complex compound-containing composition comprising the iridium complex compound according to claim 1 or 2.

4. The iridium complex compound-containing composition according to claim 3 , further comprising a solvent.

5. A method for manufacturing an organic electroluminescent device having at least an anode, a cathode, and at least one organic layer between the anode and the cathode on a substrate, comprising: At least one of the organic layers is an emitting layer, A method for producing an organic electroluminescent device, comprising: forming the light-emitting layer by wet film-forming the iridium complex compound-containing composition according to claim 4 .

6. An organic electroluminescent device having at least an anode, a cathode, and at least one organic layer between the anode and the cathode on a substrate, At least one of the organic layers is an emitting layer, An organic electroluminescent device comprising the iridium complex compound according to claim 1 or 2 in the light-emitting layer.

7. An iridium complex compound-containing composition comprising the iridium complex compound according to claim 1 or 2 and an iridium complex compound represented by the following formula (3): 【Chemistry 3】 In formula (3), Ir represents an iridium atom, and Ar has a structure represented by the following formula (2): 【Chemistry 4】 In formula (2), the dashed line represents a bond to Ar in formula (3), and m is an integer of 1 to 6. The substituents R in formula (3) and formula (2) are each independently a hydrogen atom, D or F. Substituent R in formula (3) and formula (2) １ are each independently a hydrogen atom, D, F, Cl, Br, I, or —N(R′) ２ , -CN, -NO ２ , -OH, -COOR', -C(=O)R', -C(=O)NR', -P(=O)(R') ２ , -S(=O)R', -S(=O) ２ R', -OS(=O) ２ R' is a linear, branched, or cyclic alkyl group having from 1 to 6 carbon atoms, a linear, branched alkoxy group having from 1 to 4 carbon atoms, a linear, branched, or cyclic alkylthio group having from 1 to 4 carbon atoms, a linear or branched alkenyl group having from 2 to 4 carbon atoms, a linear or branched alkynyl group having from 2 to 4 carbon atoms, an aromatic group having from 5 to 60 carbon atoms, a heteroaromatic group having from 5 to 60 carbon atoms, a diarylamino group having from 10 to 40 carbon atoms, an arylheteroarylamino group having from 10 to 40 carbon atoms, or a diheteroarylamino group having from 10 to 40 carbon atoms. These groups may be substituted with one or more R' other than a hydrogen atom. Each R' is independently a hydrogen atom, D, F, -CN, a linear, branched, or cyclic alkyl group having from 1 to 6 carbon atoms, a linear or branched alkenyl group having from 2 to 4 carbon atoms, or a linear or branched alkynyl group having from 2 to 4 carbon atoms.

8. An iridium complex compound-containing composition as described in claim 7, further containing a solvent.

9. A method for manufacturing an organic electroluminescent device having at least an anode, a cathode, and at least one organic layer between the anode and the cathode on a substrate, comprising: At least one of the organic layers is an emitting layer, A method for producing an organic electroluminescent device, comprising: forming the light-emitting layer by wet film-forming the iridium complex compound-containing composition according to claim 8 .

10. An organic electroluminescent device having at least an anode, a cathode, and at least one organic layer between the anode and the cathode on a substrate, At least one of the organic layers is an emitting layer, An organic electroluminescent device, comprising the iridium complex compound according to claim 1 or 2 and an iridium complex compound represented by the following formula (3) in the light-emitting layer: 【Chemistry 5】 In formula (3), Ir represents an iridium atom, and Ar has a structure represented by the following formula (2): 【Chemistry 6】 In formula (2), the dashed line represents a bond to Ar in formula (3), and m is an integer of 1 to 6. The substituents R in formula (3) and formula (2) are each independently a hydrogen atom, D or F. Substituent R in formula (3) and formula (2) １ are each independently a hydrogen atom, D, F, Cl, Br, I, or —N(R′) ２ , -CN, -NO ２ , -OH, -COOR', -C(=O)R', -C(=O)NR', -P(=O)(R') ２ , -S(=O)R', -S(=O) ２ R', -OS(=O) ２ R' is a linear, branched, or cyclic alkyl group having from 1 to 6 carbon atoms, a linear, branched alkoxy group having from 1 to 4 carbon atoms, a linear, branched, or cyclic alkylthio group having from 1 to 4 carbon atoms, a linear or branched alkenyl group having from 2 to 4 carbon atoms, a linear or branched alkynyl group having from 2 to 4 carbon atoms, an aromatic group having from 5 to 60 carbon atoms, a heteroaromatic group having from 5 to 60 carbon atoms, a diarylamino group having from 10 to 40 carbon atoms, an arylheteroarylamino group having from 10 to 40 carbon atoms, or a diheteroarylamino group having from 10 to 40 carbon atoms. These groups may be substituted with one or more R' other than a hydrogen atom. Each R' is independently a hydrogen atom, D, F, -CN, a linear, branched, or cyclic alkyl group having from 1 to 6 carbon atoms, a linear or branched alkenyl group having from 2 to 4 carbon atoms, or a linear or branched alkynyl group having from 2 to 4 carbon atoms.

11. A display device comprising the organic electroluminescent device according to claim 6 .

12. A lighting device comprising the organic electroluminescent device according to claim 6 .

13. A display device comprising the organic electroluminescent element of claim 10.

14. A lighting device comprising the organic electroluminescent element described in claim 10.

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