Organic electroluminescent element

Abstract

The present invention addresses the problem of providing: a material for organic EL elements, said material being excellent in terms of hole injection / transport performance, electron blocking ability, and stability and durability in the state of a thin film; and an organic EL element having high efficiency, low drive voltage and long service life and obtained by combining the above-described material and various organic EL element materials that are excellent in terms of the injection / transport performance of holes and electrons, electron blocking ability, and stability and durability in the state of a thin film, in such a manner that the respective characteristics of the materials can be effectively exerted.　The present invention is an organic EL element comprising a specific arylamine compound as a material constituting a second hole transport layer, wherein the difference between the HOMO level of the second hole transport layer and the HOMO level of a first hole transport layer is 0.15 eV or less.

Description

[Technical Field]

[0001] The present invention relates to an organic electroluminescent element, which is a self-luminescent element suitable for various display devices, and more specifically to an organic electroluminescent element (hereinafter abbreviated as organic EL element) using a specific arylamine compound. [Background technology]

[0002] Because organic EL elements are self-emissive elements, they are brighter, more visible, and capable of sharper displays compared to liquid crystal elements, which has led to active research into them.

[0003] In 1987, CWTang et al. at Eastman Kodak made organic light-emitting diodes (OLEDs) practical by developing a multilayer structure in which various roles were assigned to different materials. They layered a phosphor capable of transporting electrons with an organic material capable of transporting holes, and injected the charges of both into the phosphor layer to cause light emission, achieving an emission of 1000 cd / m² at a voltage of 10V or less. 2 The above high brightness is achieved (see, for example, Patent Documents 1 and 2).

[0004] To date, many improvements have been made to commercialize organic EL elements, and the various roles of the stacked structure have been further subdivided. High efficiency and durability have now been achieved with field-emitting elements that sequentially arrange an anode, hole injection layer, hole transport layer, light-emitting layer, electron transport layer, electron injection layer, and cathode on a substrate (see, for example, Non-Patent Document 1).

[0005] Furthermore, attempts have been made to utilize triplet excitons to further improve luminescence efficiency, and the use of phosphorescent compounds is being considered (see, for example, Non-Patent Literature 2). Devices utilizing luminescence by thermally activated delayed fluorescence (TADF) have also been developed. In 2011, Adachi et al. at Kyushu University achieved an external quantum efficiency of 5.3% with a device using thermally activated delayed fluorescence material (see, for example, Non-Patent Literature 3).

[0006] The light-emitting layer can generally be produced by doping a charge-transporting compound generally referred to as a host material with a fluorescent compound, a phosphorescent compound, or a material that emits delayed fluorescence. As described in the non-patent literature, the selection of organic materials in an organic EL device greatly affects various characteristics such as the efficiency and durability of the device (see, for example, Non-Patent Document 2).

[0007] In an organic EL device, light is obtained when charges injected from both electrodes recombine in the light-emitting layer. However, it is important how to efficiently transfer both positive and negative charges, holes and electrons, to the light-emitting layer, and it is necessary to make the device have excellent carrier balance. Also, by enhancing the hole injection property and the electron blocking property that blocks electrons injected from the cathode, the probability of recombination of holes and electrons can be improved, and furthermore, by confining excitons generated in the light-emitting layer, high luminous efficiency can be obtained. Therefore, the role played by the hole transport material is important, and there is a demand for a hole transport material with high hole injection property, high hole mobility, high electron blocking property, and furthermore, high durability against electrons.

[0008] Regarding the lifespan of the device, the heat resistance and amorphousness of the material are also important. In materials with low heat resistance, thermal decomposition occurs even at low temperatures due to the heat generated during device driving, and the material deteriorates. In materials with low amorphousness, crystallization of the thin film occurs even in a short time, and the device deteriorates. Therefore, the materials to be used are required to have high heat resistance and good amorphousness.

[0009] Hitherto, as hole transport materials used in organic EL devices, N,N'-diphenyl-N,N'-di(α-naphthyl)benzidine (NPD) and various aromatic amine derivatives have been known (see, for example, Patent Document 1 and Patent Document 2). NPD has good hole transport ability, but the glass transition point (Tg) serving as an index of heat resistance is as low as 96°C, and deterioration of device characteristics due to crystallization occurs under high-temperature conditions (see, for example, Non-Patent Document 4). Also, among the aromatic amine derivatives described in the said patent documents, the hole mobility is 10 -3 cm 2Compounds having a mobility superior to / Vs are known (see, for example, Patent Document 1 and Patent Document 2), but since the electron blocking property is insufficient, some electrons pass through the light emitting layer, and an improvement in light emitting efficiency cannot be expected. Therefore, for further higher efficiency, materials with higher electron blocking property, more stable thin films, and higher heat resistance have been demanded. Although there are reports of highly durable aromatic amine derivatives (see, for example, Patent Document 3), they are used as charge transport materials for electrophotographic photoreceptors, and there are no examples of use as organic EL elements.

[0010] As compounds with improved properties such as heat resistance and hole injection property, arylamine compounds having a substituted carbazole structure have been proposed (see, for example, Patent Document 4 and Patent Document 5). In devices using these compounds for the hole injection layer or the hole transport layer, although improvements such as heat resistance and light emitting efficiency have been made, they are not yet sufficient, and further reduction of the driving voltage and further increase of the light emitting efficiency are demanded.

[0011] In order to improve the device characteristics of organic EL devices and the yield of device fabrication, by combining materials excellent in hole and electron injection / transport performance, thin film stability and durability, an element with high efficiency of recombination of holes and electrons, high light emitting efficiency, low driving voltage, and long life is demanded.

[0012] Also, in order to improve the device characteristics of organic EL devices, by combining materials excellent in hole and electron injection / transport performance, thin film stability and durability, an element with high efficiency, low driving voltage, and long life with balanced carriers is demanded.

Prior Art Documents

Patent Documents

[0013]

Patent Document 1

Patent Document 2

Patent Document 3

[0014] [Non-Patent Document 1] Proceedings of the 9th Workshop of the Japan Society of Applied Physics, pp. 55-61 (2001) [Non-Patent Document 2] Proceedings of the 9th Workshop of the Japan Society of Applied Physics, pp. 23-31 (2001) [Non-Patent Document 3] Appl.Phys.Let.,98,083302(2011) [Non-Patent Document 4] Proceedings of the 3rd Meeting of the Organic EL Symposium, pages 13-14 (2006) [Overview of the Initiative]

[0015] The object of the present invention is to provide a material for organic EL elements that has excellent hole injection and transport performance, electron blocking capability, and stability and durability in a thin film state, and further, to provide a highly efficient, low-drive voltage, and long-life organic EL element by combining this material with various other materials for organic EL elements that have excellent hole and electron injection and transport performance, electron blocking capability, stability and durability in a thin film state, in a way that effectively brings out the characteristics of each material.

[0016] The physical properties that the organic compound used in the organic EL element to be provided by the present invention should possess include: (1) good hole injection characteristics, (2) high hole mobility, (3) stable thin film state, and (4) excellent heat resistance. Furthermore, the physical properties that the organic EL element to be provided by the present invention should possess include: (1) high luminous efficiency and power efficiency, (2) low practical driving voltage, and (3) long lifespan.

[0017] Therefore, in order to achieve the above objectives, the inventors focused on the fact that triarylamine compounds have excellent hole injection and transport capabilities, as well as thin film stability and durability. As a result of diligently studying various triarylamine compounds, they found that using a triarylamine compound with a specific structure as the material for the hole transport layer allows for efficient transport of holes injected from the anode side. Furthermore, they discovered that the above objectives can be achieved by making the hole transport layer a two-layer structure and giving each layer a specific configuration, thus completing the present invention.

[0018] In other words, the present invention relates to the following organic EL element.

[0019] 1) An organic electroluminescent element having at least a first hole transport layer, a second hole transport layer, a light-emitting layer, and an electron transport layer between the anode and cathode, in this order from the anode side, wherein the second hole transport layer contains a triarylamine compound represented by the following general formula (1), and the absolute value of the difference between the HOMO level of the second hole transport layer and the HOMO level of the first hole transport layer is 0.15 eV or less.

[0020] [ka] (In the formula, A represents the group represented by the following general formula (2-1), B represents a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, or a substituted or unsubstituted condensed aromatic group. C represents a group represented by the following general formula (2-1), a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, or a substituted or unsubstituted condensed aromatic group.

[0021] [ka] (In the formula, the dashed lines represent the joints, R1 represents a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, a linear or branched alkyl group having 1 to 6 carbon atoms which may be substituted, a cycloalkyl group having 5 to 10 carbon atoms which may be substituted, a linear or branched alkenyl group having 2 to 6 carbon atoms which may be substituted, a linear or branched alkyloxy group having 1 to 6 carbon atoms which may be substituted, a cycloalkyloxy group having 5 to 10 carbon atoms which may be substituted, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, a substituted or unsubstituted condensed polycyclic aromatic group, or a substituted or unsubstituted aryloxy group. n is the number of R1 groups, representing an integer from 0 to 3. When n is 2 or 3, the R1 groups may be identical or different, and they may be bonded to each other via single bonds, substituted or unsubstituted methylene groups, oxygen atoms, or sulfur atoms to form a ring. L1 represents a divalent group of a substituted or unsubstituted aromatic hydrocarbon, a substituted or unsubstituted aromatic heterocycle, or a substituted or unsubstituted condensed polycyclic aromatic. m is the number of L1 elements, representing an integer between 1 and 3. When m is 2 or 3, L1 elements may be identical or different. Ar1 and Ar2 each independently represent a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, or a substituted or unsubstituted condensed polycyclic aromatic group.

[0022] 2) The organic electroluminescent element according to 1), wherein the group represented by the general formula (2-1) is the group represented by the general formula (2-2) below.

[0023] [ka] (In the formula, Ar1, Ar2, L1, m, n, and R1 are defined in the same way as in the general formula (2-1) above.)

[0024] 3) The organic electroluminescent element according to 1), wherein the group represented by the general formula (2-1) is the group represented by the general formula (2-3) below.

[0025] [ka] (In the formula, Ar1, Ar2, n, and R1 are defined the same as in the general formula (2-1) above. p represents 0 or 1.)

[0026] 4) The organic electroluminescent element according to 1), wherein the group represented by the general formula (2-1) is the group represented by the general formula (2-4) below.

[0027] [ka] (In the formula, Ar1 and Ar2 are defined the same as in the general formula (2-1) above. p represents 0 or 1.)

[0028] 5) An organic electroluminescent element according to any one of claims 1) to 4), wherein the first hole transport layer contains a triarylamine compound represented by general formula (3).

[0029] [ka] (In the formula, D, E, and F each independently represent a group represented by the following general formula (4-1), a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, or a substituted or unsubstituted condensed polycyclic aromatic group. However, at least one of D, E, and F is a group represented by the following general formula (4-1).)

[0030] [ka] (In the formula, the dashed lines represent the joints, L2 represents a divalent group of a substituted or unsubstituted aromatic hydrocarbon, a substituted or unsubstituted aromatic heterocycle, or a substituted or unsubstituted condensed polycyclic aromatic. q represents an integer between 0 and 3, and when q is 2 or 3, L2 can be the same or different from each other. R2 and R3 independently represent a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, a linear or branched alkyl group having 1 to 6 carbon atoms which may be substituted, a cycloalkyl group having 5 to 10 carbon atoms which may be substituted, a linear or branched alkenyl group having 2 to 6 carbon atoms which may be substituted, a linear or branched alkyloxy group having 1 to 6 carbon atoms which may be substituted, a cycloalkyloxy group having 5 to 10 carbon atoms which may be substituted, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, a substituted or unsubstituted condensed polycyclic aromatic group, or a substituted or unsubstituted aryloxy group. r represents an integer from 0 to 4, and s represents an integer from 0 to 3. When r is from 2 to 4, R2 may be the same or different from each other. When s is 2 or 3, R3 may be the same or different from each other. R2s may bond to each other, R3s to each other, or R2s and R3s may bond to each other via single bonds, substituted or unsubstituted methylene groups, oxygen atoms, or sulfur atoms to form a ring. X1 represents O, S, NR4, or CR5R6, and if two or more of D, E, and F are groups represented by general formula (4-1), then X1 may be identical or different from each other. R4 represents a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, a linear or branched alkyl group having 1 to 6 carbon atoms which may be substituted, a cycloalkyl group having 5 to 10 carbon atoms which may be substituted, a linear or branched alkenyl group having 2 to 6 carbon atoms which may be substituted, a linear or branched alkyloxy group having 1 to 6 carbon atoms which may be substituted, a cycloalkyloxy group having 5 to 10 carbon atoms which may be substituted, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, a substituted or unsubstituted condensed polycyclic aromatic group, or a substituted or unsubstituted aryloxy group. R5 and R6 independently represent a linear or branched alkyl group having 1 to 6 carbon atoms, which may be substituted; a cycloalkyl group having 5 to 10 carbon atoms, which may be substituted; a linear or branched alkenyl group having 2 to 6 carbon atoms, which may be substituted; a substituted or unsubstituted aromatic hydrocarbon group; a substituted or unsubstituted aromatic heterocyclic group; a substituted or unsubstituted condensed polycyclic aromatic group; or a substituted or unsubstituted aryloxy group. R5 and R6 may be bonded to each other via a single bond, a substituted or unsubstituted methylene group, an oxygen atom, or a sulfur atom to form a ring.

[0031] 6) The organic electroluminescent element according to 5), wherein two of D, E, and F in the general formula (3) are groups represented by the general formula (4-1), and X1 is independently NR4 or CR5R6.

[0032] 7) The organic electroluminescent element according to 5), wherein two of D, E, and F in the general formula (3) are groups represented by the general formula (4-1), one X1 is the NR4, and the other X1 is the CR5R6.

[0033] 8) The organic electroluminescent element according to any one of claims 1) to 7), wherein the light-emitting layer contains a blue light-emitting dopant.

[0034] 9) The organic electroluminescence device according to 8) above, wherein the blue light-emitting dopant is a compound represented by the following general formula (5-1) or (5-2).

[0035]

Chemical formula

[0036]

Chemical formula

[0037] 10) The organic electroluminescent element according to any one of claims 1) to 9), wherein the light-emitting layer contains an anthracene derivative having an anthracene skeleton.

[0038] In general formulas (2-1) to (2-3) and (4-1), the "substituted or unsubstituted aromatic hydrocarbon group," "substituted or unsubstituted aromatic heterocyclic group," or "substituted or unsubstituted condensed polycyclic aromatic group" represented by R1 to R6 include, specifically, phenyl group, biphenylyl group, terphenylyl group, naphthyl group, anthracenyl group, phenantrenyl group, fluorenyl group, spirobifluorenyl group, indenyl group, pyrenyl group, perilenyl group, fluoranthenyl group, triphenylenyl group, pyridyl group, pyrimidinyl group, triazinyl group, furyl group, pyrrolyl group, thienyl group, quinolyl group, isoquinolyl group, benzof In addition to lanyl groups, benzothienyl groups, indolyl groups, carbazolyl groups, benzoxazolyl groups, benzothiazolyl groups, quinoxalinyl groups, benzimidazolyl groups, pyrazolyl groups, dibenzofuranyl groups, dibenzothienyl groups, naphthilidinyl groups, phenanthrolinyl groups, acridinyl groups, and carboninyl groups, aryl groups having 6 to 30 carbon atoms or heteroaryl groups having 2 to 30 carbon atoms can be selected. These substituents may be substituted on benzene rings, or multiple substituents substituted on the same benzene ring may be bonded to each other via single bonds, substituted or unsubstituted methylene groups, substituted or unsubstituted amine groups, oxygen atoms, or sulfur atoms to form a ring.

[0039] In general formulas (2-1) to (2-3) and (4-1), the "substituted or unsubstituted aryloxy groups" represented by R1 to R6 include, specifically, phenyloxy group, biphenylyloxy group, terphenylyloxy group, naphthyloxy group, anthracenyloxy group, phenantrenyloxy group, fluorenyloxy group, indenyloxy group, pyrenyloxy group, and perilennyloxy group.

[0040] In general formulas (2-1) to (2-3) and (4-1), R1 to R6 represent "a linear or branched alkyl group having 1 to 6 carbon atoms that may have substituents," "a cycloalkyl group having 5 to 10 carbon atoms that may have substituents," or "a linear or branched alkenyl group having 2 to 6 carbon atoms that may have substituents." Specifically, the "linear or branched alkyl group having 1 to 6 carbon atoms," "a cycloalkyl group having 5 to 10 carbon atoms," or "a linear or branched alkenyl group having 2 to 6 carbon atoms" can refer to a methyl group, an ethyl group, an n-propyl group, etc. Examples include the 1-butyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, n-hexyl group, cyclopentyl group, cyclohexyl group, 1-adamantyl group, 2-adamantyl group, vinyl group, allyl group, isopropenyl group, and 2-butenyl group. A benzene ring substituted with these substituents, or multiple substituents substituted on the same benzene ring, may be bonded to each other via single bonds, substituted or unsubstituted methylene groups, substituted or unsubstituted amine groups, oxygen atoms, or sulfur atoms to form a ring.

[0041] In general formulas (2-1) to (2-3) and (4-1), R1 to R4 represent "linear or branched alkyloxy groups having 1 to 6 carbon atoms that may have substituents" or "cycloalkyloxy groups having 5 to 10 carbon atoms that may have substituents." Specifically, "linear or branched alkyloxy groups having 1 to 6 carbon atoms" or "cycloalkyloxy groups having 5 to 10 carbon atoms" include methyloxy group, ethyloxy group, n-propyloxy group, isopropyloxy group, n-butyloxy group, Examples include tert-butyloxy group, n-pentyloxy group, n-hexyloxy group, cyclopentyloxy group, cyclohexyloxy group, cycloheptyloxy group, cyclooctyloxy group, 1-adamantyloxy group, 2-adamantyloxy group, etc., and benzene rings substituted with these substituents, or substituents that are multiple times substituted on the same benzene ring, may be bonded to each other via single bonds, substituted or unsubstituted methylene groups, substituted or unsubstituted amine groups, oxygen atoms, or sulfur atoms to form a ring.

[0042] In general formulas (2-1) to (2-3) and (4-1), R1 to R6 represent "substituted aromatic hydrocarbon groups," "substituted aromatic heterocyclic groups," "substituted condensed polycyclic aromatic groups," "substituted aryloxy groups," "linear or branched alkyl groups having 1 to 6 carbon atoms that may have substituents," "cycloalkyl groups having 5 to 10 carbon atoms that may have substituents," "linear or branched alkenyl groups having 2 to 6 carbon atoms that may have substituents," "linear or branched alkyloxy groups having 1 to 6 carbon atoms that may have substituents," or "cycloalkyloxy groups having 5 to 10 carbon atoms that may have substituents." Specifically, the "substituents" in these groups include deuterium atoms, cyano groups, nitro groups; halogen atoms such as fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms; silyl groups such as trimethylsilyl groups and triphenylsilyl groups; linear or branched alkyl groups having 1 to 6 carbon atoms such as methyl groups, ethyl groups, and propyl groups; methyloxy groups, ethyloxy groups, propyloxy groups, etc. Linear or branched alkyloxy groups with 1 to 6 carbon atoms; alkenyl groups such as vinyl and allyl groups; aryloxy groups such as phenyloxy and tolyloxy groups; arylalkyloxy groups such as benzyloxy and phenethyloxy groups; aromatic groups such as phenyl, biphenylyl, terphenylyl, naphthyl, anthracenyl, phenantrenyl, fluorenyl, spirobifluorenyl, indenyl, pyrenyl, perilenyl, fluoranthenyl, and triphenylenyl groups. Fragrance hydrocarbon groups or condensed polycyclic aromatic groups; examples include aromatic heterocyclic groups such as pyridyl, thienyl, furyl, pyrrolyl, quinolyl, isoquinolyl, benzofuranyl, benzothienyl, indolyl, carbazolyl, benzoxazolyl, benzothiazolyl, quinoxalinyl, benzimidazolyl, pyrazolyl, dibenzofuranyl, dibenzothienyl, and carboninyl groups, and these substituents may be further substituted with the substituents exemplified above.Furthermore, the benzene rings substituted with these substituents, or the substituents that are multiple times substituted on the same benzene ring, may be bonded to each other via single bonds, substituted or unsubstituted methylene groups, substituted or unsubstituted amine groups, oxygen atoms, or sulfur atoms to form a ring.

[0043] In general formulas (2-1) to (2-4), the "substituted or unsubstituted aromatic hydrocarbon group," "substituted or unsubstituted aromatic heterocyclic group," or "substituted or unsubstituted condensed polycyclic aromatic group" represented by Ar1 and Ar2 can be the same as those shown for the "aromatic hydrocarbon group," "aromatic heterocyclic group," or "condensed polycyclic aromatic group" represented by R1 to R6 in general formulas (2-1) to (2-3) and (4-1), and the possible embodiments can also be the same.

[0044] The substituents in the "substituted aromatic hydrocarbon group," "substituted aromatic heterocyclic group," or "substituted condensed polycyclic aromatic group" represented by Ar1 and Ar2 in general formulas (2-1) to (2-4) are the same as those shown for the substituents represented by R1 to R6 in general formulas (2-1) to (2-3) and (4-1), and the possible embodiments are also the same.

[0045] The "substituted or unsubstituted aromatic hydrocarbon group," "substituted or unsubstituted aromatic heterocyclic group," or "substituted or unsubstituted condensed polycyclic aromatic group" represented by B and C in general formula (1) and D, E and F in general formula (3) can be the same as those shown for the "aromatic hydrocarbon group," "aromatic heterocyclic group," or "condensed polycyclic aromatic group" represented by R1 to R6 in general formulas (2-1) to (2-3) and (4-1), and the possible embodiments can also be the same.

[0046] The substituents in the "substituted aromatic hydrocarbon group," "substituted aromatic heterocyclic group," or "substituted condensed polycyclic aromatic group" represented by B and C in general formula (1) and D, E and F in general formula (3) are the same as those shown for the substituents represented by R1 to R6 in general formulas (2-1) to (2-3) and (4-1), and the possible embodiments are also the same.

[0047] In general formulas (2-1), (2-2), and (4-1), the "divalent groups of substituted or unsubstituted aromatic hydrocarbons, substituted or unsubstituted aromatic heterocycles, or substituted or unsubstituted condensed polycyclic aromatics" represented by L1 and L2 include, specifically, benzene, biphenyl, terphenyl, tetrakisphenyl, s Examples include ethylene, naphthalene, anthracene, acenaphthalene, fluorene, phenanthrene, indan, pyrene, triphenylene, pyridine, pyrimidine, triazine, pyrrole, furan, thiophene, quinoline, isoquinoline, benzofuran, benzothiophene, indoline, carbazole, carboline, benzoxazole, benzothiazole, quinoxaline, benzimidazole, pyrazole, dibenzofuran, dibenzothiophene, naphthyridine, phenanthroline, and acridine.

[0048] Furthermore, the "divalent groups of substituted or unsubstituted aromatic hydrocarbons, substituted or unsubstituted aromatic heterocycles, or substituted or unsubstituted fused polycyclic aromatics" represented by L1 and L2 in general formulas (2-1), (2-2), and (4-1) represent divalent groups obtained by removing two hydrogen atoms from the above-mentioned "aromatic hydrocarbons," "aromatic heterocycles," or "fused polycyclic aromatics." These divalent groups may also have substituents, and examples of "substituents" are the same as those shown for the "substituents" represented by R1 to R6 in general formulas (2-1) to (2-3) and (4-1), and the possible embodiments are also the same.

[0049] As the monovalent group represented by general formula (2-1), the group represented by general formula (2-2) is preferred from the viewpoint of hole injection and transport capacity, the group represented by general formula (2-3) is more preferred, and the group represented by general formula (2-4) is particularly preferred.

[0050] In the groups represented by general formulas (2-1) to (2-4), from the viewpoint of hole injection and transport capacity, it is preferable that Ar1 and Ar2 are substituted or unsubstituted aromatic hydrocarbon groups or substituted or unsubstituted condensed polycyclic aromatic groups, more preferably substituted or unsubstituted phenyl groups, substituted or unsubstituted naphthyl groups, or substituted or unsubstituted biphenylyl groups, and particularly preferably unsubstituted phenyl groups or unsubstituted naphthyl groups.

[0051] In the triarylamine compound represented by general formula (1), from the viewpoint of hole implantation and transport capacity, B and C are preferably independently substituted or unsubstituted aromatic hydrocarbon groups or substituted or unsubstituted condensed aromatic groups, and more preferably substituted or unsubstituted phenyl groups, substituted or unsubstituted naphthyl groups, substituted or unsubstituted phenantrenyl groups, or substituted or unsubstituted fluorenyl groups.

[0052] In the group represented by general formula (4-1), from the viewpoint of hole injection and transport capacity, X1 is preferably NR4 or CR5R6, and more preferably CR5R6. Furthermore, R5 and R6 are each preferably independently a linear or branched alkyl group having 1 to 6 carbon atoms, which may have substituents, or a substituted or unsubstituted aromatic hydrocarbon group, more preferably a linear alkyl group having 1 to 6 carbon atoms or an unsubstituted aromatic hydrocarbon group, and particularly preferably a linear alkyl group having 1 to 4 carbon atoms or an unsubstituted phenyl group.

[0053] In the group represented by general formula (4-1), it is preferable that both r and s are 0 from the viewpoint of hole injection and transport capacity. Furthermore, it is preferable that L2 is a phenylene group and q is 0 or 1.

[0054] In a triarylamine compound represented by general formula (3), it is preferable that two of D, E, and F are groups represented by general formula (4-1) from the viewpoint of hole implantation and transport capacity. In this case, it is preferable that the two X1 groups are independently NR4 or CR5R6, and more preferably that both X1 groups are CR5R6.

[0055] In the triarylamine compound represented by general formula (3), from the viewpoint of hole implantation and transport capacity, it is preferable that among D, E, and F, the group other than the group represented by general formula (4-1) is independently a substituted or unsubstituted aromatic hydrocarbon group or a substituted or unsubstituted condensed aromatic group, and more preferably a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, or a substituted or unsubstituted biphenylyl group.

[0056] In general formulas (5-1) and (5-2), the "substituted or unsubstituted aromatic hydrocarbons" or "substituted or unsubstituted aromatic heterocycles" represented by Q1 to Q3 include, specifically, benzene, naphthalene, anthracene, fluorene, phenanthrene, pyridine, pyrimidine, triazine, pyrrole, furan, thiophene, quinoline, isoquinoline, indene, benzofuran, benzothiophene, indole, indoline, carbazole, carbolin, benzoxazole, benzothiazole, quinoxaline, benzimidazole, pyrazole, dibenzofuran, dibenzothiophene, naphthyridine, phenanthroline, acridine, and others.

[0057] Furthermore, these may have substituents, and examples of substituents include those similar to those indicated for "substituted linear or branched alkyl groups having 1 to 6 carbon atoms," "substituted cycloalkyl groups having 5 to 10 carbon atoms," or "substituted linear or branched alkenyl groups having 2 to 6 carbon atoms" represented by R1 to R6 in general formulas (2-1) to (2-3) and (4-1). In addition, these substituents may be bonded to each other via single bonds, substituted or unsubstituted methylene groups, oxygen atoms, or sulfur atoms to form a ring.

[0058] In general formulas (5-1) and (5-2), X2 represents B, P, P=O, or P=S. B is defined as a boron atom, P as a phosphorus atom, P=O as a phosphorus atom double-bonded to an oxygen atom, and P=S as a phosphorus atom double-bonded to a sulfur atom.

[0059] In general formulas (5-1) and (5-2), Y1 to Y3 are, independently, N-R7, C-R8R9, O, S, Se, or Si-R 10 R 11 This represents: N-R7 is a nitrogen atom with R7 as a substituent, C-R8R9 is a carbon atom with R8 and R9 as substituents, O is an oxygen atom, S is a sulfur atom, Se is a selenium atom, and Si-R 10 R 11 is R 10 and R 11 This is defined as a silicon atom having as a substituent.

[0060] R7~R in general formulas (5-1) and (5-2) 11In the expression "a linear or branched alkyl group having 1 to 6 carbon atoms which may have substituents," "a cycloalkyl group having 5 to 10 carbon atoms which may have substituents," or "a linear or branched alkenyl group having 2 to 6 carbon atoms which may have substituents," examples of "a linear or branched alkyl group having 1 to 6 carbon atoms," "a cycloalkyl group having 5 to 10 carbon atoms which may have substituents," or "a linear or branched alkenyl group having 2 to 6 carbon atoms" include, specifically, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, n-hexyl group, cyclopentyl group, cyclohexyl group, 1-adamantyl group, 2-adamantyl group, vinyl group, allyl group, isopropenyl group, 2-butenyl group, and the like. Furthermore, these may have substituents, and examples of substituents include those similar to those shown for "substituted linear or branched alkyl groups having 1 to 6 carbon atoms," "substituted cycloalkyl groups having 5 to 10 carbon atoms," or "substituted linear or branched alkenyl groups having 2 to 6 carbon atoms" represented by R1 to R6 in the general formulas (2-1) to (2-3) and (4-1).

[0061] R7~R in general formulas (5-1) and (5-2) 11In the expression "a linear or branched alkyloxy group having 1 to 6 carbon atoms which may have substituents" or "a cycloalkyloxy group having 5 to 10 carbon atoms which may have substituents," examples of the "linear or branched alkyloxy group having 1 to 6 carbon atoms" or "a cycloalkyloxy group having 5 to 10 carbon atoms which may have substituents" include methyloxy group, ethyloxy group, n-propyloxy group, isopropyloxy group, n-butyloxy group, tert-butyloxy group, n-pentyloxy group, n-hexyloxy group, cyclopentyloxy group, cyclohexyloxy group, cycloheptyloxy group, cyclooctyloxy group, 1-adamantyloxy group, and 2-adamantyloxy group. Furthermore, these groups may have substituents, and examples of substituents include those similar to those shown for "substituted linear or branched alkyl groups having 1 to 6 carbon atoms," "substituted cycloalkyl groups having 5 to 10 carbon atoms," or "substituted linear or branched alkenyl groups having 2 to 6 carbon atoms" represented by R1 to R6 in the general formulas (2-1) to (2-3) and (4-1).

[0062] R7~R in general formulas (5-1) and (5-2) 11 In the terms "substituted or unsubstituted aromatic hydrocarbon group" and "substituted or unsubstituted aromatic heterocyclic group" represented by the above formulas (2-1) to (2-3) and (4-1), the "aromatic hydrocarbon group" and "aromatic heterocyclic group" specifically include phenyl group, biphenylyl group, terphenylyl group, naphthyl group, anthracenyl group, phenantrenyl group, pyridyl group, pyrimidinyl group, triazinyl group, furyl group, pyrrolyl group, thienyl group, and the like. These groups may also have substituents, and the substituents are the same as those shown for "substituted linear or branched alkyl groups having 1 to 6 carbon atoms," "substituted cycloalkyl groups having 5 to 10 carbon atoms," or "substituted linear or branched alkenyl groups having 2 to 6 carbon atoms" represented by R1 to R6 in the above general formulas (2-1) to (2-3) and (4-1).

[0063] R7~R in general formulas (5-1) and (5-2) 11 In the "substituted or unsubstituted aryloxy group" represented by the above formulas (2-1) to (2-3) and (4-1), the "aryloxy group" can specifically be a phenyloxy group, biphenylyloxy group, terphenylyloxy group, naphthyloxy group, anthracenyloxy group, phenantrenyloxy group, fluorenyloxy group, indenyloxy group, pyrenyloxy group, perilennyloxy group, etc. Furthermore, these groups may have substituents, and the substituents can be the same as those shown for the "substituted linear or branched alkyl group having 1 to 6 carbon atoms", "substituted cycloalkyl group having 5 to 10 carbon atoms", or "substituted linear or branched alkenyl group having 2 to 6 carbon atoms" represented by R1 to R6 in the above general formulas (2-1) to (2-3) and (4-1).

[0064] In the compounds represented by general formulas (5-1) and (5-2), from the viewpoint of luminescence efficiency, the "aromatic hydrocarbon" or "aromatic heterocycle" in the "substituted or unsubstituted aromatic hydrocarbon" or "substituted or unsubstituted aromatic heterocycle" represented by Q1 to Q3 is preferably benzene, naphthalene, phenanthrene, pyridine, pyrimidine, indene, benzofuran, benzothiophene, or indole, and more preferably benzene or naphthalene.

[0065] In the compounds represented by general formulas (5-1) and (5-2), from the viewpoint of luminescence efficiency, Y1 is preferably N-R7, O, or S, and more preferably O or S. Furthermore, in the compound represented by general formula (5-1), from the viewpoint of luminescence efficiency, at least one of Y2 and Y3 is preferably N-R7, and more preferably both are N-R7. R7 is preferably a "substituted or unsubstituted aromatic hydrocarbon group," and more preferably a substituted or unsubstituted phenyl group, biphenylyl group, terphenylyl group, or naphthyl group.

[0066] Of the compounds represented by the general formulas (5-1) and (5-2) mentioned above, compounds represented by the following general formulas (5-3) to (5-6) are preferred.

[0067] [ka]

[0068] [ka]

[0069] [ka]

[0070] [ka] (In formulas (5-3) to (5-6), X2, Y 1、 Y 2、 Y3 is defined identically to the general formulas (5-1) and (5-2) above, Y4 is N-R7, C-R8R9, O, S, Se or Si-R 10 R 11 One of the following will be selected: R7, R8, R9, R 10 and R 11 This is defined identically to the general formulas (5-1) and (5-2) above, Z may be the same or different from each other, CR 12 or N, R 12R may be the same or different from each other and represents a hydrogen atom, a deuterium atom, a halogen group, a cyano group, a nitro group, a linear or branched alkyl group having 1 to 6 carbon atoms which may be substituted, a cycloalkyl group having 5 to 10 carbon atoms which may be substituted, a linear or branched alkyloxy group having 1 to 6 carbon atoms which may be substituted, a linear or branched alkylthiooxy group having 1 to 6 carbon atoms which may be substituted, a linear or branched alkylamine group having 1 to 6 carbon atoms which may be substituted, a linear or branched alkylsilyl group having 3 to 10 carbon atoms which may be substituted, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted arylthiooxy group, a substituted or unsubstituted arylamine group, or a substituted or unsubstituted arylsilyl group. 12 These groups may be bonded to each other or to adjacent substituents to form alicyclic or aromatic single or polycyclic rings, and the carbon atoms in the alicyclic or aromatic single or polycyclic rings may be substituted with one or more complex atoms selected from N, S, and O.

[0071] R in general formulas (5-3) to (5-6) 12In the expression "a linear or branched alkyl group having 1 to 6 carbon atoms which may have substituents" or "a cycloalkyl group having 5 to 10 carbon atoms which may have substituents," examples of the "linear or branched alkyl group having 1 to 6 carbon atoms" or "a cycloalkyl group having 5 to 10 carbon atoms which may have substituents" include, specifically, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, n-hexyl group, cyclopentyl group, cyclohexyl group, 1-adamantyl group, 2-adamantyl group, and the like. Furthermore, these may have substituents, and examples of substituents include those similar to those shown for "substituted linear or branched alkyl groups having 1 to 6 carbon atoms," "substituted cycloalkyl groups having 5 to 10 carbon atoms," or "substituted linear or branched alkenyl groups having 2 to 6 carbon atoms" represented by R1 to R6 in the general formulas (2-1) to (2-3) and (4-1).

[0072] R in general formulas (5-3) to (5-6) 12 In the "linear or branched alkyloxy group having 1 to 6 carbon atoms that may have substituents" represented by (2-1) to (2-3) and (4-1), specific examples of the "linear or branched alkyloxy group having 1 to 6 carbon atoms" include methyloxy group, ethyloxy group, n-propyloxy group, isopropyloxy group, n-butyloxy group, tert-butyloxy group, n-pentyloxy group, and n-hexyloxy group. Furthermore, these groups may have substituents, and examples of substituents include those similar to those shown for "substituted linear or branched alkyl group having 1 to 6 carbon atoms", "substituted cycloalkyl group having 5 to 10 carbon atoms", or "substituted linear or branched alkenyl group having 2 to 6 carbon atoms" represented by R1 to R6 in the general formulas (2-1) to (2-3) and (4-1).

[0073] R in general formulas (5-3) to (5-6) 12In the "linear or branched alkyl thioxy group having 1 to 6 carbon atoms that may have substituents" represented by (2-1) to (2-3) and (4-1), specific examples of the "linear or branched alkyl thioxy group having 1 to 6 carbon atoms that may have substituents" include methyl thioxy group, ethyl thioxy group, n-propyl thioxy group, isopropyl thioxy group, n-butyl thioxy group, isobutyl thioxy group, tert-butyl thioxy group, n-pentyl thioxy group, isopentyl thioxy group, neopentyl thioxy group, n-hexyl thioxy group, etc. Furthermore, these may have substituents, and examples of substituents include those similar to those shown for "substituted linear or branched alkyl groups having 1 to 6 carbon atoms", "substituted cycloalkyl groups having 5 to 10 carbon atoms", or "substituted linear or branched alkenyl groups having 2 to 6 carbon atoms that have substituents" represented by R1 to R6 in the general formulas (2-1) to (2-3) and (4-1).

[0074] R in general formulas (5-3) to (5-6) 12 In the "linear or branched alkylamine group having 1 to 6 carbon atoms that may have substituents" represented by (2-1) to (2-3) and (4-1), specific examples of the "linear or branched alkylamine group having 1 to 6 carbon atoms that may have substituents" include methylamine group, dimethylamine group, ethylamine group, diethylamine group, n-propylamine group, di-n-propylamine group, isopropylamine group, diisopropylamine group, n-butylamine group, isobutylamine group, tert-butylamine group, n-pentylamine group, isopentylamine group, neopentylamine group, and n-hexylamine group. Furthermore, these may have substituents, and examples of substituents include those similar to those shown for "substituted linear or branched alkyl groups having 1 to 6 carbon atoms", "substituted cycloalkyl groups having 5 to 10 carbon atoms", or "substituted linear or branched alkenyl groups having 2 to 6 carbon atoms that have substituents" represented by R1 to R6 in the general formulas (2-1) to (2-3) and (4-1).

[0075] R in general formulas (5-3) to (5-6) 12 In the "linear or branched alkylsilyl group having 3 to 10 carbon atoms that may have substituents" represented by (2-1) to (2-3) and (4-1), specific examples of the "linear or branched alkylsilyl group having 3 to 10 carbon atoms that may have substituents" include trimethylsilyl group, triethylsilyl group, tri-n-propylsilyl group, triisopropylsilyl group, n-butyldimethylsilyl group, isobutyldimethylsilyl group, tert-butyldimethylsilyl group, and the like. Furthermore, these may have substituents, and examples of substituents are the same as those shown for "substituents" in the "linear or branched alkyl group having 1 to 6 carbon atoms with substituents," "cycloalkyl group having 5 to 10 carbon atoms with substituents," or "linear or branched alkenyl group having 2 to 6 carbon atoms with substituents" represented by R1 to R6 in the general formulas (2-1) to (2-3) and (4-1).

[0076] R in general formulas (5-3) to (5-6) 12 In the "substituted or unsubstituted aromatic hydrocarbon group" or "substituted or unsubstituted aromatic heterocyclic group" represented by the above formulas (2-1) to (2-3) and (4-1), the "aromatic hydrocarbon group" or "aromatic heterocyclic group" can specifically include phenyl group, biphenylyl group, terphenylyl group, naphthyl group, anthracenyl group, phenantrenyl group, pyridyl group, pyrimidinyl group, triazinyl group, furyl group, pyrrolyl group, thienyl group, and the like. These may also have substituents, and the substituents can be the same as those shown for "substituted linear or branched alkyl groups having 1 to 6 carbon atoms", "substituted cycloalkyl groups having 5 to 10 carbon atoms", or "substituted linear or branched alkenyl groups having 2 to 6 carbon atoms" represented by R1 to R6 in the above general formulas (2-1) to (2-3) and (4-1).

[0077] R in general formulas (5-3) to (5-6) 12In the "substituted or unsubstituted aryloxy group" represented by , specific examples of "aryloxy group" include phenyloxy group, biphenylyloxy group, terphenylyloxy group, naphthyloxy group, anthracenyloxy group, phenantrenyloxy group, fluorenyloxy group, indenyloxy group, pyrenyloxy group, and perilennyloxy group. These may also have substituents, and the substituents are the same as those shown for "substituted linear or branched alkyl groups with 1 to 6 carbon atoms", "substituted cycloalkyl groups with 5 to 10 carbon atoms", or "substituted linear or branched alkenyl groups with 2 to 6 carbon atoms" represented by R1 to R6 in the general formulas (2-1) to (2-3) and (4-1).

[0078] R in general formulas (5-3) to (5-6) 12 In the "substituted or unsubstituted arylthiooxy group" represented by (2-1) to (2-3) and (4-1), the "arylthiooxy group" can specifically be phenylthiooxy group, biphenylylthiooxy group, terphenylylthiooxy group, naphthylthiooxy group, anthracenylthiooxy group, phenantrenylthiooxy group, fluorenylthiooxy group, indenylthiooxy group, pyrenylthiooxy group, perilenylthiooxy group, etc. Furthermore, these may have substituents, and the substituents can be the same as those shown for the "substituted linear or branched alkyl group having 1 to 6 carbon atoms", "substituted cycloalkyl group having 5 to 10 carbon atoms", or "substituted linear or branched alkenyl group having 2 to 6 carbon atoms" represented by R1 to R6 in the general formulas (2-1) to (2-3) and (4-1).

[0079] R in general formulas (5-3) to (5-6) 12Specifically, the "arylamine group" in the "substituted or unsubstituted arylamine group" represented by the above formulas (2-1) to (2-3) and (4-1) can be the phenylamine group, biphenylylamine group, terphenylylamine group, naphthylamine group, anthracenylamine group, phenantrenylamine group, fluorenylamine group, indenylamine group, pyrenylamine group, perilennylamine group, diphenylamine group, dibiphenylamine group, diterphenylamine group, dinaphthylamine group, dianthracenylamine group, difluorenylamine group, diindenylamine group, etc. Furthermore, these may have substituents, and the substituents can be the same as those shown for the "substituted linear or branched alkyl group having 1 to 6 carbon atoms", "substituted cycloalkyl group having 5 to 10 carbon atoms", or "substituted linear or branched alkenyl group having 2 to 6 carbon atoms" represented by R1 to R6 in the above general formulas (2-1) to (2-3) and (4-1).

[0080] R in general formulas (5-3) to (5-6) 12 In the "substituted or unsubstituted arylsilyl group" represented by , specific examples of the "arylsilyl group" include triphenylsilyl group, trinaphthylsilyl group, and terphenylylsilyl group. These may also have substituents, and the substituents are the same as those shown for the "substituted linear or branched alkyl group having 1 to 6 carbon atoms", "substituted cycloalkyl group having 5 to 10 carbon atoms", or "substituted linear or branched alkenyl group having 2 to 6 carbon atoms" represented by R1 to R6 in the general formulas (2-1) to (2-3) and (4-1).

[0081] The triarylamine compound represented by the general formula (1) has the following characteristics: (1) good hole injection characteristics, (2) high hole mobility, (3) excellent electron blocking ability, (4) stable thin film state, and (5) excellent heat resistance. Therefore, it is suitable for use as a constituent material for the hole transport layer of the organic EL device of the present invention.

[0082] The organic EL element of the present invention, which uses the triarylamine compound represented by the general formula (1) above as a constituent material for the hole transport layer, exhibits higher hole mobility, superior electron blocking ability, excellent amorphous properties, and a stable thin film state compared to conventional hole transport materials. Therefore, it achieves high efficiency, low driving voltage, and long lifespan.

[0083] In the present invention, the hole transport layer has a two-layer structure consisting of a first hole transport layer and a second hole transport layer. By forming the second hole transport layer, located adjacent to the light-emitting layer, with a triarylamine compound represented by the general formula (1), the electron blocking performance of the triarylamine compound can be maximized, enabling the realization of a more efficient and longer-lasting organic EL element.

[0084] Furthermore, in the present invention, by setting the absolute value of the difference between the HOMO level of the second hole transport layer and the HOMO level of the first hole transport layer to 0.15 eV or less, excellent hole injection characteristics and hole transport performance can be achieved, thereby realizing an organic EL element with higher efficiency, lower drive voltage, and longer lifespan. [Brief explanation of the drawing]

[0085] [Figure 1] The diagram shows the structural formulas of compounds 1-1 to 1-12, which are examples of triarylamine compounds represented by general formula (1). [Figure 2] The diagram shows the structural formulas of compounds 1-13 to 1-24, which are examples of triarylamine compounds represented by general formula (1). [Figure 3] The diagram shows the structural formulas of compounds 1-25 to 1-36, which are examples of triarylamine compounds represented by general formula (1). [Figure 4] The diagram shows the structural formulas of compounds 1-37 to 1-48, which are examples of triarylamine compounds represented by general formula (1). [Figure 5]The diagram shows the structural formulas of compounds 1-49 to 1-60, which are examples of triarylamine compounds represented by general formula (1). [Figure 6] The diagram shows the structural formulas of compounds 1-61 to 1-72, which are examples of triarylamine compounds represented by general formula (1). [Figure 7] The diagram shows the structural formulas of compounds 1-73 to 1-84, which are examples of triarylamine compounds represented by general formula (1). [Figure 8] The diagram shows the structural formulas of compounds 1-85 to 1-96, which are examples of triarylamine compounds represented by general formula (1). [Figure 9] The diagram shows the structural formulas of compounds 1-97 to 1-105, which are examples of triarylamine compounds represented by general formula (1). [Figure 10] The diagram shows the structural formulas of compounds 3-1 to 3-12, which are examples of triarylamine compounds represented by general formula (3). [Figure 11] The diagram shows the structural formulas of compounds 3-13 to 3-24, which are examples of triarylamine compounds represented by general formula (3). [Figure 12] The diagram shows the structural formulas of compounds 3-25 to 3-36, which are examples of triarylamine compounds represented by general formula (3). [Figure 13] The diagram shows the structural formulas of compounds 3-37 to 3-48, which are examples of triarylamine compounds represented by general formula (3). [Figure 14] The diagram shows the structural formulas of compounds 3-49 to 3-60, which are examples of triarylamine compounds represented by general formula (3). [Figure 15] The diagram shows the structural formulas of compounds 3-61 to 3-72, which are examples of triarylamine compounds represented by general formula (3). [Figure 16] The diagram shows the structural formulas of compounds 3-73 to 3-84, which are examples of triarylamine compounds represented by general formula (3). [Figure 17]The diagram shows the structural formulas of compounds 3-85 to 3-96, which are examples of triarylamine compounds represented by general formula (3). [Figure 18] The diagram shows the structural formulas of compounds 3-97 to 3-108, which are examples of triarylamine compounds represented by general formula (3). [Figure 19] This figure shows the structural formulas of compounds 3-109 to 3-120, which are examples of triarylamine compounds represented by general formula (3). [Figure 20] The diagram shows the structural formulas of compounds 3-121 to 3-132, which are examples of triarylamine compounds represented by general formula (3). [Figure 21] The diagram shows the structural formulas of compounds 3-133 to 3-144, which are examples of triarylamine compounds represented by general formula (3). [Figure 22] The diagram shows the structural formulas of compounds 3-145 to 3-156, which are examples of triarylamine compounds represented by general formula (3). [Figure 23] The diagram shows the structural formulas of compounds 3-157 to 3-168, which are examples of triarylamine compounds represented by general formula (3). [Figure 24] The diagram shows the structural formulas of compounds 3-169 to 3-180, which are examples of triarylamine compounds represented by general formula (3). [Figure 25] The diagram shows the structural formulas of compounds 3-181 to 3-195, which are examples of triarylamine compounds represented by general formula (3). [Figure 26] The diagram shows the structural formulas of compounds 3-196 to 3-207, which are examples of triarylamine compounds represented by general formula (3). [Figure 27] The diagram shows the structural formulas of compounds 3-208 to 3-219, which are examples of triarylamine compounds represented by general formula (3). [Figure 28] This figure shows the structural formulas of compounds 3-220 to 3-231, which are examples of triarylamine compounds represented by general formula (3). [Figure 29]The diagram shows the structural formulas of compounds 3-232 to 3-243, which are examples of triarylamine compounds represented by general formula (3). [Figure 30] The diagram shows the structural formulas of compounds 3-244 to 3-255, which are examples of triarylamine compounds represented by general formula (3). [Figure 31] The diagram shows the structural formulas of compounds 3-256 to 3-269, which are examples of triarylamine compounds represented by general formula (3). [Figure 32] The diagram shows the structural formulas of compounds 3-270 to 3-282, which are examples of triarylamine compounds represented by general formula (3). [Figure 33] The diagram shows the structural formulas of compounds 3-283 to 3-297, which are examples of triarylamine compounds represented by general formula (3). [Figure 34] The diagram shows the structural formulas of compounds 3-298 to 3-311, which are examples of triarylamine compounds represented by general formula (3). [Figure 35] The diagram shows the structural formulas of compounds 3-312 to 3-326, which are examples of triarylamine compounds represented by general formula (3). [Figure 36] The diagram shows the structural formulas of compounds 3-327 to 3-338, which are examples of triarylamine compounds represented by general formula (3). [Figure 37] The diagram shows the structural formulas of compounds 3-339 to 3-353, which are examples of triarylamine compounds represented by general formula (3). [Figure 38] The diagram shows the structural formulas of compounds 3-354 to 3-368, which are examples of triarylamine compounds represented by general formula (3). [Figure 39] The diagram shows the structural formulas of compounds 3-369 to 3-384, which are examples of triarylamine compounds represented by general formula (3). [Figure 40] The diagram shows the structural formulas of compounds 3-385 to 3-392, which are examples of triarylamine compounds represented by general formula (3). [Figure 41]The diagram shows the structures of compounds 5-1-1 to 5-1-15 as examples of compounds represented by the general formula (5-1). [Figure 42] The diagram shows the structural formulas of compounds 5-1-16 to 5-1-26 as examples of compounds represented by the general formula (5-1). [Figure 43] The diagram shows the structural formulas of compounds 5-2-1 to 5-2-12, which are examples of compounds represented by the general formula (5-2). [Figure 44] This figure shows an example of the configuration of the organic EL element of the present invention. [Modes for carrying out the invention]

[0086] Specific examples of preferred triarylamine compounds represented by general formula (1) that are suitably used in the organic EL element of the present invention are shown in Figures 1 to 9, specific examples of preferred triarylamine compounds represented by general formula (3) are shown in Figures 10 to 40, specific examples of preferred compounds represented by general formula (5-1) are shown in Figures 41 to 42, and specific examples of preferred compounds represented by general formula (5-2) are shown in Figure 43, but the invention is not limited to these compounds.

[0087] The triarylamine compound represented by general formula (1) can be purified by column chromatography, adsorption using silica gel, activated carbon, activated clay, etc., recrystallization or crystallization with a solvent, or sublimation. The compound can be identified by NMR analysis. It is preferable to measure the melting point, glass transition temperature (Tg), and work function as physical properties. The melting point is an indicator of vapor deposition properties, the glass transition temperature (Tg) is an indicator of the stability of the thin film state, and the work function is an indicator of hole transport and hole blocking properties. It is preferable to use a compound used in the organic EL device of the present invention that has been purified by column chromatography, adsorption using silica gel, activated carbon, activated clay, etc., recrystallization or crystallization with a solvent, sublimation, etc., and finally purified by sublimation.

[0088] The melting point and glass transition temperature (Tg) can be measured using a powder with a high-sensitivity differential scanning calorimeter (Bruker AXS, DSC3100SA).

[0089] The HOMO levels of each layer can be determined by fabricating a 100 nm thin film on an ITO substrate and using an ionization potential measurement device (Sumitomo Heavy Industries, Ltd., PYS-202).

[0090] The structure of the organic EL element of the present invention includes, in order on a substrate, an anode, a first hole transport layer, a second hole transport layer, an emissive layer, an electron transport layer, and a cathode. Other structures include one having a hole injection layer between the anode and the first hole transport layer, one having a hole blocking layer between the emissive layer and the electron transport layer, and one having an electron injection layer between the electron transport layer and the cathode. In these multilayer structures, for example, the hole injection layer and the first hole transport layer can be combined, or the electron injection layer and electron transport layer can be combined. It is also possible to have a structure in which two or more organic layers having the same function are stacked, such as a configuration with two stacked first hole transport layers, a configuration with two stacked second hole transport layers, a configuration with two stacked emissive layers, or a configuration with two stacked electron transport layers. In the structure of the organic EL element of the present invention, it is preferable that the second hole transport layer is adjacent to the emissive layer and also functions as an electron blocking layer.

[0091] As the anode of the organic EL element of the present invention, electrode materials with a large work function, such as ITO or gold, are used. As the hole injection layer of the organic EL element of the present invention, materials such as starburst-type triphenylamine derivatives and various triphenylamine tetramers; porphyrin compounds represented by copper phthalocyanine; acceptor-type heterocyclic compounds such as hexacyanoazatriphenylene; and coated polymer materials can be used.

[0092] As hole-transporting materials that can be used as the first hole transport layer of the organic EL element of the present invention, benzidine derivatives such as N,N'-diphenyl-N,N'-di(m-tolyl)benzidine (TPD), N,N'-diphenyl-N,N'-di(α-naphthyl)benzidine (NPD), and N,N,N',N'-tetrabiphenylylbenzidine, as well as 1,1-bis[4-(di-4-tolylamino)phenyl]cyclohexane (TAPC), triarylamine compounds represented by the general formula (1) or the general formula (3), and various triphenylamine derivatives can be used. Furthermore, it is preferable to use the triarylamine compound represented by the general formula (3) as the first hole transport layer of the organic EL element of the present invention.

[0093] Furthermore, in the hole injection layer or the first hole transport layer, materials that are P-doped with trisbromophenylamine hexachloroantimony, radialene derivatives (see, for example, Patent Document 7), or polymer compounds having the structure of a benzidine derivative such as TPD as a substructure can be used in addition to the materials normally used in the layer.

[0094] As the second hole transport layer of the organic EL element of the present invention, a triarylamine compound represented by the general formula (1) is used. Examples of hole-transporting materials that can be mixed with or used simultaneously with the triarylamine compound represented by the general formula (1) include carbazole derivatives such as 4,4',4''-tri(N-carbazolyl)triphenylamine (TCTA), 9,9-bis[4-(carbazole-9-yl)phenyl]fluorene, 1,3-bis(carbazole-9-yl)benzene (mCP), and 2,2-bis(4-carbazole-9-ylphenyl)adamantane (Ad-Cz), and compounds having an electron-blocking effect such as compounds having a triphenylsilyl group and a triarylamine structure, represented by 9-[4-(carbazole-9-yl)phenyl]-9-[4-(triphenylsilyl)phenyl]-9H-fluorene.

[0095] In the present invention, the absolute value of the difference between the HOMO level of the second hole transport layer and the HOMO level of the first hole transport layer is 0.15 eV or less, more preferably 0.12 eV or less, and even more preferably 0.10 eV or less.

[0096] As the light-emitting layer of the organic EL element of the present invention, in addition to metal complexes of quinolinol derivatives such as Alq3, various metal complexes, anthracene derivatives, bis-styrylbenzene derivatives, pyrene derivatives, oxazole derivatives, poly(p-phenylenevinylene) derivatives, etc., can be used. The light-emitting layer may also be composed of a host material and a dopant material. Anthracene derivatives are preferably used as the host material, but in addition to the light-emitting materials mentioned above, heterocyclic compounds having an indole ring as a substructure of the fused ring, heterocyclic compounds having a carbazole ring as a substructure of the fused ring, carbazole derivatives, thiazole derivatives, benzimidazole derivatives, polydialkylfluorene derivatives, etc., can be used. As the dopant material, pyrene derivatives and compounds represented by the general formulas (5-1) or (5-2) are preferably used, but quinacridone, coumarin, rubrene, perylene and their derivatives, benzopyran derivatives, indenophenanthrene derivatives, rhodamine derivatives, aminostyryl derivatives, etc., can also be used.

[0097] Furthermore, phosphorescent materials can be used as light-emitting materials. As phosphorescent materials, metal complex phosphorescent materials such as iridium and platinum can be used. Green phosphorescent materials such as Ir(ppy)3, blue phosphorescent materials such as Firpic and Fir6, and red phosphorescent materials such as Btp2Ir(acac) can be used. As the host material in this case, hole-injection and transport host materials such as 4,4'-di(N-carbazolyl)biphenyl (CBP), TCTA, and mCP carbazole derivatives can be used. As electron-transport host materials, p-bis(triphenylsilyl)benzene (UGH2) and 2,2',2''-(1,3,5-phenylene)-tris(1-phenyl-1H-benzimidazole) (TPBI) can be used, and high-performance organic EL devices can be fabricated.

[0098] To avoid concentration quenching, doping of the phosphorescent luminescent material into the host material is preferably carried out by co-deposition in an amount ranging from 1 to 30 weight percent of the entire luminescent layer.

[0099] Furthermore, it is also possible to use materials that emit delayed fluorescence as light-emitting materials, such as PIC-TRZ, CC2TA, PXZ-TRZ, and CDCB derivatives such as 4CzIPN (see, for example, Non-Patent Document 3).

[0100] As the hole-blocking layer of the organic EL element of the present invention, metal complexes of phenanthroline derivatives such as bathocuproine (BCP) and quinolinol derivatives such as aluminum(III) bis(2-methyl-8-quinolinate)-4-phenylphenolate (hereinafter abbreviated as BAlq), as well as various rare earth complexes, triazole derivatives, triazine derivatives, oxadiazole derivatives, and other compounds having hole-blocking activity can be used.

[0101] As the electron transport layer of the organic EL element of the present invention, metal complexes of quinolinol derivatives including Alq3 and BAlq, various metal complexes, triazole derivatives, triazine derivatives, oxadiazole derivatives, pyridine derivatives, pyrimidine derivatives, benzimidazole derivatives, thiadiazole derivatives, anthracene derivatives, carbodiimide derivatives, quinoxaline derivatives, pyridoindole derivatives, phenanthroline derivatives, silole derivatives, and the like can be used.

[0102] As the electron injection layer of the organic EL element of the present invention, alkali metal salts such as lithium fluoride and cesium fluoride, alkaline earth metal salts such as magnesium fluoride, metal complexes of quinolinol derivatives such as lithium quinolinol, metal oxides such as aluminum oxide, or metals such as ytterbium (Yb), samarium (Sm), calcium (Ca), strontium (Sr), and cesium (Cs) can be used. However, the electron injection layer can be omitted by selecting the electron transport layer and cathode in the preferred manner.

[0103] Furthermore, in the electron injection layer or electron transport layer, a material that is N-doped with a metal such as cesium can be used in addition to the material normally used in the layer.

[0104] As the cathode of the organic EL element of the present invention, electrode materials with a low work function, such as aluminum, or alloys with an even lower work function, such as magnesium-silver alloy, magnesium-indium alloy, or aluminum-magnesium alloy, can be used as electrode materials.

[0105] The materials used in each layer constituting the organic EL element of the present invention described above may be deposited individually, or they may be used as single layers deposited by mixing them with other materials. They may also be used in a laminated structure of layers deposited individually, layers deposited by mixing, or layers deposited individually and layers deposited by mixing. These materials can be formed into thin films by known methods such as vapor deposition, spin coating, and inkjet printing. [Examples]

[0106] The embodiments of the present invention will be described in detail below with reference to examples, but the present invention is not limited to the following embodiments.

[0107] [Synthesis Example 1] <Synthesis of bis(4-naphthalene-2-ylphenyl)-(2',5'-diphenylbiphenyl-4-yl)amine (compound (1-4))> In a reaction vessel, 10.0 g of bis(4-naphthalene-2-ylphenyl)amine, 11.0 g of 4-bromo-2',5'-diphenyl-biphenyl, 0.1 g of palladium(II) acetate, 0.2 g of tri(t-butyl)phosphine, and 2.7 g of t-butoxysodium were charged and stirred under reflux in toluene for 3 hours. After cooling, the mixture was filtered, and the resulting filtrate was concentrated to obtain the crude product. The crude product was purified by crystallization using a toluene / acetone mixed solvent to obtain 9.0 g of white powder bis(4-naphthalene-2-ylphenyl)-(2',5'-diphenyl-biphenyl-4-yl)amine (compound (1-4)) (yield: 52.3%).

[0108] [ka]

[0109] Regarding the obtained white powder, 1 The following 39 hydrogen signals were detected by 1H-NMR (CDCl3) measurement, and the structure was identified. δ(ppm)=8.06(2H), 7.92(6H), 7.78(4H), 7.73(1H), 7.68(5H), 7.53(7H), 7.42(1H), 7.39-7.23(9H), 7.14(4H).

[0110] [Synthesis Example 2] <Synthesis of (2',5'-diphenyl-biphenyl-4-yl)-(4-naphthalene-1-ylphenyl)phenanthrene-9-ylamine (compound (1-58))> In a reaction vessel, 8.5 g of (2',5'-diphenyl-biphenyl-4-yl)-(4-naphthalen-1-ylphenyl)-amine, 4.8 g of 9-bromophenanthrene, 0.1 g of palladium(II) acetate, 0.3 g of tri(t-butyl)phosphine, and 2.3 g of t-butoxysodium were charged and stirred under reflux in toluene for 3 hours. After cooling, the filtrate obtained by filtration was concentrated to obtain the crude product. The obtained crude product was purified by crystallization using a toluene / acetone mixed solvent to obtain 8.3 g of white powder (yield: 73.1%) of (2',5'-diphenyl-biphenyl-4-yl)-(4-naphthalen-1-ylphenyl)-phenanthrene-9-ylamine (compound (1-58)).

[0111] [ka]

[0112] Regarding the obtained white powder, 1 The following 37 hydrogen signals were detected by 1H-NMR (CDCl3) measurement, and the structure was identified. δ(ppm)=8.79(1H), 8.75(1H), 8.14(1H), 8.03(1H), 7.92(1H), 7.85(2H), 7.72(6H) , 7.65(2H), 7.60(1H), 7.50(7H), 7.42(1H), 7.36(3H), 7.27-7.18(6H), 7.09(4H).

[0113] [Synthesis Example 3] <Synthesis of (2',5'-diphenyl-biphenyl-4-yl)-(4-naphthalene-2-ylphenyl)phenanthrene-9-ylamine (compound (1-59))> In a reaction vessel, 8.0 g of (2',5'-diphenyl-biphenyl-4-yl)-(4-naphthalen-2-ylphenyl)-amine, 4.5 g of 9-bromophenanthrene, 0.1 g of palladium(II) acetate, 0.2 g of tri(t-butyl)phosphine, and 2.2 g of t-butoxysodium were charged and stirred under reflux in toluene for 3 hours. After cooling, the filtrate obtained by filtration was concentrated to obtain the crude product. The obtained crude product was purified by crystallization using a toluene / acetone mixed solvent to obtain 6.6 g (yield: 61.7%) of a pale yellow powder of (2',5'-diphenyl-biphenyl-4-yl)-(4-naphthalen-2-ylphenyl)-phenanthrene-9-ylamine (compound (1-59)).

[0114] [ka]

[0115] Regarding the pale yellow powder obtained, 1 The following 37 hydrogen signals were detected by 1H-NMR (CDCl3) measurement, and the structure was identified. δ(ppm)=8.79(1H), 8.74(1H), 8.09(1H), 8.01(1H), 7.86(4H), 7.75(1H), 7.71(5H) , 7.66(2H), 7.60(3H), 7.50(5H), 7.39(1H), 7.34-7.23(6H), 7.20(2H), 7.07(4H).

[0116] [Synthesis Example 4] Synthesis of (2",5"-diphenyl-[1,1';4',1"]terphenyl-4-yl)-(4-naphthalene-2-ylphenyl)-phenylamine (compound (1-69)) In a reaction vessel, 6.0 g of (4-naphthalen-2-yl-phenyl)-phenyl-amine, 10.3 g of 4-bromo-2”,5”-diphenyl-[1,1';4',1”]terphenyl, 0.1 g of palladium(II) acetate, 0.2 g of tri(t-butyl)phosphine, and 2.3 g of t-butoxysodium were charged and stirred under reflux overnight in toluene. After cooling, the filtrate obtained by filtration was concentrated to obtain the crude product. The crude product was purified by column chromatography (support: silica gel, eluent: dichloromethane / n-heptane) to obtain 7.1 g (yield: 51.7%) of the white powder (2”,5”-diphenyl-[1,1';4',1”]terphenyl-4-yl)-(4-naphthalen-2-yl-phenyl)-phenyl-amine (compound (1-69)).

[0117] [ka]

[0118] Regarding the obtained white powder, 1 The following 37 hydrogen signals were detected by 1H-NMR (CDCl3) measurement, and the structure was identified. δ(ppm)=8.04(1H), 7.91(3H), 7.73(5H), 7.66(2H), 7.56(2H), 7.51(7H), 7.42(1H), 7.39-7.18(15H), 7.10(1H).

[0119] [Synthesis Example 5] <(2",5"-diphenyl-[1,1';4',1"]terphenyl-4-yl)-(4-phenanthrene-9-ylphenyl)-phenylamine (compound (1-83)) synthesis> Into a reaction vessel, 11.0 g of (4-phenanthren-9-yl-phenyl)-phenyl-amine, 16.2 g of 4-bromo-2″,5″-[1,1′;4′,1″]terphenyl, 0.1 g of palladium(II) acetate, 0.3 g of tri(t-butyl)phosphine, and 3.7 g of sodium t-butoxide were charged, and the mixture was refluxed and stirred overnight under a toluene solvent. After cooling, the filtrate obtained by filtration was concentrated to obtain a crude product. The obtained crude product was purified by column chromatography (carrier: silica gel, eluent: dichloromethane / n-heptane) to obtain 11.2 g (yield: 48.5%) of a white powder of (2″,5″-diphenyl-[1,1′;4′,1″]terphenyl-4-yl)-(4-phenanthren-9-yl-phenyl)-phenyl-amine (Compound (1-83)).

[0120]

Chemical formula

[0121] [[ID=​​​​​​​​​​​In a reaction vessel, 50.0 g of 4-bromoaniline, 113.9 g of 4,4,5,5-tetramethyl-2-[1,1':4',1''-terphenyl]-2'-yl-1,3,2-dioxaborolane, 350 mL of toluene, 88 mL of ethanol, 80.4 g of potassium carbonate, and 290 mL of water were charged. 6.7 g of tetrakistriphenylphosphine palladium was added, and the mixture was stirred under reflux for 14 hours. After cooling, the mixture was separated, and the organic layer was washed sequentially with water and saturated brine, and dried over anhydrous magnesium sulfate. The drying agent was removed by filtration, and the filtrate was concentrated. 450 mL of heptane was added to the residue, and the mixture was stirred overnight at room temperature. The solid was collected by filtration to obtain 77.8 g (yield: 83.3%) of a yellowish-white powder of [1,1':2',1'':4'',1'''-quarterphenyl]-4-amine.

[0123] [ka]

[0124] In a reaction vessel, 55.0 g of [1,1':2',1'':4'',1'''-quarterphenyl]-4-amine, 74.9 g of 2-(4-bromophenyl)naphthalene, 28.0 g of t-butoxysodium, 420 mL of toluene, 0.9 g of tris(dibenzylideneacetone)dipalladium, and 2,2'-bis(diphenylphosphin)-1,1'-binaphthyl were charged and stirred under reflux for 15 hours. The mixture was cooled to 80°C, and the solid was removed by thermal filtration using a funnel lined with Celite. The filtrate was heated and stirred, 50 g of silica gel was added at 80°C, and the mixture was stirred for 1 hour. The solid was then removed by thermal filtration. The filtrate was concentrated, and the residue was recrystallized in a toluene / acetone mixed solvent to obtain 69.5 g (yield: 68.3%) of N-(4-(2-naphthyl)phenyl)-[1,1':2',1'':4'',1'''-quarterphenyl]-4-amine as a yellowish-white powder.

[0125] [ka]

[0126] In a reaction vessel, 69.5 g of N-(4-(2-naphthyl)phenyl)-[1,1':2',1'':4'',1'''-quarterphenyl]-4-amine, 45.1 g of 1-bromo-4-iodobenzene, 25.7 g of t-butoxysodium, 700 mL of toluene, 2.5 g of copper iodide, and 2.3 g of N,N'-dimethylethylenediamine were charged and stirred under reflux for 16 hours. After cooling to 80°C, the solid was removed by thermal filtration using a funnel lined with Celite. The filtrate was concentrated, and the residue was purified by column chromatography (support: silica gel, eluent: dichloromethane / n-heptane) to obtain 59.4 g (yield: 65.5%) of a yellowish-white powder of N-(4-bromophenyl)-N-(4-(2-naphthyl)phenyl)-[1,1':2',1'':4'',1'''-quarterphenyl]-4-amine.

[0127] [ka]

[0128] In a reaction vessel, 12.0 g of N-(4-bromophenyl)-N-(4-(2-naphthyl)phenyl)-[1,1':2',1'':4'',1'''-quarterphenyl]-4-amine, 5.3 g of 3-(2-naphthyl)phenylboronic acid, 84 mL of toluene, 21 mL of ethanol, 4.9 g of potassium carbonate, and 18 mL of water were charged. 0.4 g of tetrakistriphenylphosphine palladium was added, and the mixture was stirred under reflux for 14 hours. After cooling, 84 mL of methanol was added, and the precipitated solid was collected by filtration. 70 mL of water and 70 mL of methanol were added to the solid, and it was dispersed and washed under reflux for 1 hour. The solid was collected by filtration, 140 mL of toluene was added, and the mixture was heated to 100°C to remove the water and methanol. After cooling to 80°C, 7 g of silica gel and 7 g of activated clay were added, and the mixture was stirred for 1 hour. The solid was removed by filtration, and the filtrate was concentrated. 140 mL of acetone was added to the residue, and the mixture was stirred overnight at room temperature. The solid was collected by filtration. The solid was recrystallized in a toluene / acetone mixed solvent to obtain 11.3 g (yield: 79.6%) of N-(3'-(naphthalene-2-yl)-[1,1'-biphenyl]-4-yl)-N-(4-(naphthalene)-2-yl)phenyl)-5'-phenyl-[1,1':2',1''-terphenyl]-4-amine (compound (1-96)) as a yellowish-white powder.

[0129] [ka]

[0130] Regarding the yellowish-white powder obtained, 1 The following 43 hydrogen signals were detected by 1H-NMR (CDCl3) measurement, and the structure was identified. δ(ppm)=8.09(1H), 8.01(1H), 7.77-7.92(8H), 7.43-7.73(19H), 7.21-7.38(10H), 7.04-7.13(4H).

[0131] [Synthesis Example 7] <Synthesis of <N,9,9-triphenyl-N-(4’-phenyl-[1,1’:2’,1’’:4’’,1’’’-quarterphenyl]-4’’’-yl)-9H-fluorene-2-amine (Compound (1-97))>> Into a reaction vessel, 20.0 g of 2’-chloro-[1,1’:4’,1’’-terphenyl], 29.5 g of N-phenyl-4’-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-[1,1’-biphenyl]-4-amine, 200 mL of 1,4-dioxane, 32.1 g of potassium phosphate, and 60 mL of water were charged. 2.1 g of tris(dibenzylideneacetone)dipalladium and 2.1 g of tricyclohexylphosphine were added, and the mixture was refluxed with stirring for 14 hours. After cooling, 200 mL of methanol was added, and the precipitated solid was collected by filtration. 360 mL of chlorobenzene was added to the solid, heated to 100 °C once, cooled to 80 °C, 9 g of silica gel and 9 g of activated clay were added, and the mixture was stirred for 1 hour. The solid was removed by filtration, and the filtrate was concentrated. 360 mL of acetone was added to the residue, stirred at room temperature overnight, and the solid was collected by filtration to obtain 30.6 g (yield: 85.5%) of a pale yellowish white powder of N,4’-diphenyl-[1,1’:2’,1’’:4’’,1’’’-terphenyl]-4’’’-amine.

[0132]

Chemical Structure

[0133] Into a reaction vessel, 20.0 g of N,4'-diphenyl-[1,1':2',1'':4'',1'''-terphenyl]-4'''-amine, 18.5 g of 2-bromo-9,9-diphenyl-9H-fluorene, 200 mL of toluene, and 6.1 g of sodium t-butoxide were charged. 0.1 g of tris(dibenzylideneacetone)dipalladium and 0.2 g of a 50% toluene solution of tri(t-butyl)phosphine were added, and the mixture was refluxed with stirring for 14 hours. After cooling to 80 °C, hot filtration was performed using a funnel lined with celite to remove solids. The filtrate was heated and stirred, and 12 g of silica gel and 12 g of activated clay were added at 80 °C, followed by stirring for 1 hour. The solids were removed by filtration, and the filtrate was concentrated. The residue was recrystallized from a toluene / acetone mixed solvent to obtain 21.4 g (yield: 64.1%) of a pale yellowish-white powder of N,9,9-triphenyl-N-(4'-phenyl-[1,1':2',1'':4'',1'''-quarterphenyl]-4'''-yl)-9H-fluorene-2-amine (Compound (1-97)).

[0134] [Chemical Structure]

[0135] Regarding the obtained pale yellowish-white powder, 1 43 hydrogen signals were detected by 1H-NMR (CDCl3) measurement to identify the structure. δ (ppm) = 7.64 - 7.71 (5H), 7.58 - 7.60 (1H), 7.51 - 7.53 (1H), 7.41 - 7.48 (6H), 7.30 - 7.38 (3H), 7.14 - 7.24 (21H), 6.98 - 7.09 (6H).

[0136] [Synthesis Example 8] [Synthesis of N-([1,1'-biphenyl]-4-yl)-5'-(naphthalen-2-yl)-N-(4-(naphthalen-2-yl)phenyl)-[1,1':2',1''-terphenyl]-4-amine (Compound (1-102))] In a reaction vessel, 31.0 g of 4-bromo-2-chloro-1,1'-biphenyl, 22.0 g of 2-naphthaleneboronic acid, 240 mL of toluene, 60 mL of ethanol, 24.1 g of potassium carbonate, and 80 mL of water were charged. 1.3 g of tetrakistriphenylphosphine palladium was added, and the mixture was stirred under reflux for 15 hours. After cooling, the mixture was separated, and the organic layer was washed with water. The organic layer was stirred, heated to 100°C to confirm the absence of water, cooled to 80°C, 20 g of silica gel was added, and the mixture was stirred for 1 hour. The solid was removed by thermal filtration, and the filtrate was concentrated. The residue was recrystallized in a toluene / heptane mixed solvent to obtain 25.6 g of gray powder 2-(2-chloro-[1,1'-biphenyl]-4-yl)naphthalene (yield: 63.5%).

[0137] [ka]

[0138] In a reaction vessel, 20.0 g of 2-(2-chloro-[1,1'-biphenyl]-4-yl)naphthalene, 24.8 g of N-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-[1,1'-biphenyl]-4-amine, 160 mL of 1,4-dioxane, 27.0 g of potassium phosphate, and 60 mL of water were charged. 1.8 g of tris(dibenzylideneacetone)dipalladium and 1.8 g of tricyclohexylphosphine were added, and the mixture was stirred under reflux for 12 hours. After cooling, the mixture was concentrated. The residue, with water remaining, was extracted with toluene. The organic layer was washed sequentially with water and saturated brine, and dried over anhydrous magnesium sulfate. The drying agent was removed by filtration, the filtrate was stirred and heated, and 20 g of silica gel was added at 80°C. The mixture was stirred for 1 hour, the solid was removed by thermal filtration, and the filtrate was concentrated. By recrystallizing the residue in toluene solvent, 26.0 g (yield: 78.0%) of a yellowish-white powder of N-([1,1'-biphenyl]-4-yl)-5'-(naphthalene-2-yl)-[1,1':2',1''-terphenyl]-4-amine was obtained.

[0139] [ka]

[0140] Into the reaction vessel, 24.6 g of N-([1,1'-biphenyl]-4-yl)-5'-(naphthalen-2-yl)-[1,1':2',1''-terphenyl]-4-amine, 14.7 g of 2-(4-bromophenyl)naphthalene, 250 mL of toluene, and 6.8 g of sodium t-butoxide were charged. 0.4 g of tris(dibenzylideneacetone)dipalladium and 0.4 g of a 50% toluene solution of tri(t-butyl)phosphine were added, and the mixture was refluxed and stirred for 4 hours. After cooling to 80 °C, hot filtration was performed using a funnel lined with celite to remove the solid. The filtrate was heated and stirred, and at 80 °C, 17 g of silica gel and 17 g of activated clay were added and stirred for 1 hour. The solid was removed by filtration, and the filtrate was concentrated. The residue was purified by crystallization from a mixed solvent of toluene / acetone to obtain 21.0 g (yield: 61.5%) of a pale yellowish-white powder of N-([1,1'-biphenyl]-4-yl)-5'-(naphthalen-2-yl)-N-(4-(naphthalen-2-yl)phenyl)-[1,1':2',1''-terphenyl]-4-amine (Compound (1-102)).

[0141] [Chemical Structure]<

[0142] Regarding the obtained pale yellowish-white powder, 1 39 hydrogen signals were detected by 1H-NMR (CDCl3) measurement, and the structure was identified. δ (ppm) = 8.14 (1H), 8.01 (1H), 7.82 - 7.93 (8H), 7.71 - 7.77 (2H), 7.39 - 7.63 (13H), 7.05 - 7.32 (14H).

[0143] [Synthesis Example 9] [Synthesis of N-([1,1'-biphenyl]-4-yl)-5'-phenyl-N-(4-(3-phenylnaphthalen-1-yl)phenyl)-[1,1':2',1''-terphenyl]-4-amine (Compound (1-103))] In a reaction vessel, 32.7 g of 2'-bromo-[1,1':4',1''-terphenyl], 24.8 g of N-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-[1,1'-biphenyl]-4-amine, 320 mL of toluene, 90 mL of ethanol, 21.9 g of potassium carbonate, and 80 mL of water were charged. 1.2 g of tetrakistriphenylphosphine palladium was added, and the mixture was stirred under reflux for 13 hours. After cooling, the precipitated solid was collected by filtration, and 250 mL of methanol and 250 mL of water were added. After dispersion washing under reflux for 1 hour, the solid was collected by filtration. 750 mL of toluene was added to the solid, and it was stirred. The mixture was heated to 100°C to confirm the removal of methanol and water, and then cooled to 80°C. 10 g of silica gel was added, the mixture was stirred for 1 hour, and the solid was removed by thermal filtration. The filtrate was concentrated, and the residue was crystallized using acetone solvent to obtain 33.0 g (yield: 65.9%) of a yellowish-white powder of N-([1,1'-biphenyl]-4-yl)-5'-phenyl-[1,1':2',1''-terphenyl]-4-amine.

[0144] [ka]

[0145] Into a reaction vessel, 10.2 g of N-([1,1'-biphenyl]-4-yl)-5'-phenyl-[1,1':2',1''-terphenyl]-4-amine, 7.0 g of 1-(4-bromophenyl)-3-phenylnaphthalene, 70 mL of toluene, and 2.8 g of sodium t-butoxide were charged. 0.1 g of palladium acetate and 0.4 g of a 50% toluene solution of tri(t-butyl)phosphine were added, and the mixture was refluxed with stirring for 4 hours. After cooling to room temperature, methanol was added, and the precipitated solid was collected by filtration. 300 mL of toluene was added to the solid, and the mixture was stirred and heated. At 80 °C, 7 g of silica gel and 7 g of activated clay were added and stirred for 1 hour. The solid was removed by hot filtration, and the filtrate was concentrated. The residue was recrystallized from a dichloromethane / acetone mixed solvent to obtain 10.9 g (yield: 74.2%) of a white powder of N-([1,1'-biphenyl]-4-yl)-5'-phenyl-N-(4-(3-phenylnaphthalen-1-yl)phenyl)-[1,1':2',1''-terphenyl]-4-amine (Compound (1-103)).

[0146] [Chemical formula]

[0147] Regarding the obtained white powder, 1 41 hydrogen signals as follows were detected by 1H-NMR (CDCl3), and the structure was identified. δ (ppm) = 8.01 - 8.03 (2H), 7.94 - 7.96 (1H), 7.58 - 7.77 (9H), 7.22 - 7.53 (25H), 7.08 - 7.15 (4H).

[0148] [Synthesis Example 10] [Synthesis of <N,N-bis(biphenyl-4-yl)-6-(9,9-dimethylfluorene-2-yl)biphenyl-3-amine (Compound (3-52))> Into a reaction vessel, 13.0 g of N,N-bis(biphenyl-4-yl)-6-bromobiphenyl-3-amine, 6.8 g of (9,9-dimethylfluorene-2-yl)boronic acid, 3.9 g of potassium carbonate, and 0.54 g of tetrakistriphenylphosphine palladium were charged. 100 mL of toluene, 26 mL of ethanol, and 40 mL of water were added, and the mixture was refluxed and stirred overnight. After cooling, the organic layer was separated and successively washed with water and saturated brine. The organic layer was dried over anhydrous magnesium sulfate, and the desiccant was removed by filtration. The filtrate was concentrated, and the residue was purified by column chromatography (silica gel, heptane:toluene = 2:1) to obtain 9.0 g (yield 57%) of pale yellow powder of N,N-bis(biphenyl-4-yl)-6-(9,9-dimethylfluorene-2-yl)biphenyl-3-amine (Compound (3-52)).

[0149] [Chemical formula]

[0150] Regarding the obtained white powder, 1 39 hydrogen signals were detected by 1H-NMR (CDCl3) measurement, and the structure was identified. [[ID=十六]]δ(ppm)=7.22 - 7.68(28H), 7.12(4H), 6.99(1H), 1.22(6H).

[0151] [Synthesis Example 11] [Synthesis of N-biphenyl-4-yl-N-[2-(9,9-diphenylfluorene-4-yl)phenyl]-9,9-diphenylfluorene-2-amine (Compound (3-130))] In a reaction vessel, 20.0 g of N-biphenyl-4-yl-9,9-dimethylfluoren-2-amine, 28.8 g of 4-(2-bromophenyl)-9,9-dimethylfluoren, 8.0 g of t-butoxysodium, and 200 mL of toluene were charged. 0.12 g of palladium acetate and 0.45 g of a toluene solution of 50% t-butylphosphine were added, and the mixture was stirred under reflux for 4 hours. After cooling, the filtrate was filtered and concentrated to obtain the crude product. The crude product was purified by column chromatography (silica gel, heptane:toluene = 2:1) to obtain 31.3 g of white powder N-biphenyl-4-yl-N-[2-(9,9-diphenylfluoren-4-yl)phenyl]-9,9-diphenylfluoren-2-amine (compound (3-130)) (yield: 75.0%).

[0152] [ka]

[0153] Regarding the obtained white powder, 1 The following 43 hydrogen signals were detected by 1H-NMR (CDCl3) measurement, and the structure was identified. δ(ppm)=7.46-7.55(4H), 6.79-7.38(29H), 6.67-6.69(2H), 6.47-6.51(2H), 1.08(3H), 1.01(3H).

[0154] [Synthesis Example 12] <Synthesis of compound (5-1-11)> 45.0 g of 1-bromobenzene (D-substituted), 58.0 g of 4-tert-butylaniline, 1.0 g of palladium(II) acetate, 30.0 g of t-butosodium, 2.0 g of bis(diphenylphosphin)-1,1'-binaphthyl, and 450 mL of toluene were added to a reaction vessel and stirred under reflux for 24 hours. After cooling, the mixture was concentrated and purified by column chromatography to obtain 49.9 g (78% yield) of the following compound (5-1-11a) in powder form.

[0155] [ka]

[0156] 20.0 g of the above compound (5-1-11a), 18.4 g of the following compound (5-1-11b), 0.5 g of palladium(II) acetate, 18.9 g of t-butoxysodium, 0.8 g of tri(t-butyl)phosphine, and 200 mL of toluene were added to a reaction vessel and stirred under reflux for 24 hours. After cooling, the mixture was concentrated and purified by column chromatography to obtain 21.5 g of the following compound (5-1-11c) in powder form (84% yield).

[0157] [ka]

[0158] [ka]

[0159] 12.0 g of the above compound (5-1-11c) and 120 ml of tert-butylbenzene were added to a reaction vessel, and 42.5 ml of n-butyllithium was added dropwise at -78°C. Then, nitrogen gas was passed through while stirring at 60°C for 3 hours. Next, 11.3 g of boron tripromide was added dropwise at -78°C, and the mixture was stirred at room temperature for 1 hour. Then, 5.9 g of N,N-diisopropylethylamine was added dropwise at 0°C, and the mixture was stirred at 120°C for 2 hours. After cooling, an aqueous sodium acetate solution was added and the mixture was stirred. The mixture was extracted with ethyl acetate, and the organic layer was concentrated. Purification by column chromatography yielded 1.7 g (yield 11%) of the following compound (5-1-11) in powder form.

[0160] [ka]

[0161] For the triarylamine compounds represented by the general formula (1) or (3) obtained in Synthesis Examples 1 to 11, the glass transition points were measured using a high-sensitivity differential scanning calorimeter (manufactured by Bruker AXS, DSC3100SA). The results are shown below. Compound (1-4) 107.1°C Compound (1-58) 131.2°C Compound (1-59) 129.7°C Compound (1-69) 110.0°C Compound (1-83) 127.9°C Compound (1-96) 109.5°C Compound (1-97) 136.2°C Compound (1-102) 109.1°C Compound (1-103) 118.7°C Compound (3-52) 114.6°C Compound (3-130) 137.3°C

[0162] From the above measurement results, it can be seen that the triarylamine compounds represented by the general formula (I) or (3) used in the present invention have a glass transition point of 100°C or higher. This indicates that the thin film state is stable.

[0163] Using the triarylamine compounds represented by the general formula (1) or (3) obtained in Synthesis Examples 1 to 11, a vapor deposition film with a thickness of 100 nm was formed on an ITO substrate, and the HOMO level (ionization potential) of each layer was measured using an ionization potential measuring device (manufactured by Sumitomo Heavy Industries, Ltd., PYS-202). The results are shown below. Compound (1-4) 5.67 eV Compound (1-58) 5.72 eV Compound (1-59) 5.75 eV Compound (1-69) 5.72 eV Compound (1-83) 5.76 eV Compound (1-96) 5.69 eV Compound (1-97) 5.68 eV Compound (1-102) 5.67 eV Compound (1-103) 5.73 eV Compound (3-52) 5.66 eV Compound (3-130) 5.67 eV

[0164] For comparison, the HOMO levels were also measured for the layers formed using compounds (HTM-1), (HTM-2), and (HTM-3) with the following structural formulas. The measurement results are summarized below. Compound (HTM-1) 5.50 eV Compound (HTM-2) 5.68 eV Compound (HTM-3) 5.73 eV

[0165] [Chemical formula]

[0166] From the above measurement results, it can be seen that the triarylamine compound represented by the general formula (1) shows a suitable energy level compared to the HOMO level of 5.4 eV of common hole transport materials such as NPD and TPD, and has good hole transport ability.

[0167] [Example 1] As shown in Fig. 44, the organic EL device was fabricated by depositing a hole injection layer 3, a first hole transport layer 4, a second hole transport layer 5, a light-emitting layer 6, an electron transport layer 7, an electron injection layer 8, a cathode 9, and a capping layer 10 in this order on a glass substrate 1 on which a reflective ITO electrode was previously formed as a transparent anode.

[0168] Specifically, a glass substrate 1, on which a 50 nm thick ITO film, a 100 nm thick silver alloy reflective film, and a 5 nm thick ITO film were sequentially deposited, was ultrasonically cleaned in isopropyl alcohol for 20 minutes, and then dried on a hot plate heated to 250°C for 10 minutes. After that, UV ozone treatment was performed for 15 minutes, and then this ITO-coated glass substrate was placed in a vacuum deposition machine and the pressure was reduced to 0.001 Pa or less. Next, a hole injection layer 3 was formed covering the transparent anode 2 by binary deposition of an electron acceptor (Acceptor-1) with the following structural formula and compound (3-52) from Example 10 at a deposition rate of Acceptor-1:compound (3-52)=3:97, resulting in a film thickness of 10 nm. On this hole injection layer 3, the compound (3-52) from Example 10 was formed as the first hole transport layer 4 to a thickness of 140 nm. On top of this first hole transport layer 4, the compound (1-4) from Example 1 was formed as a second hole transport layer 5 to a thickness of 5 nm. On this second hole transport layer 5, the compound (5-1-11) from Example 8 and the compound (EMH-1) with the following structural formula were deposited as a light-emitting layer 6 by binary deposition at a deposition rate where the deposition rate ratio of compound (5-1-11):(EMH-1)=5:95, to a film thickness of 20 nm. On this light-emitting layer 6, two compounds with the following structural formulas (ETM-1) and (ETM-2) were deposited as electron transport layers 7 using a binary deposition method at a deposition rate ratio of compound (ETM-1):(ETM-2)=50:50, to form a film thickness of 30 nm. On this electron transport layer 7, lithium fluoride was formed as an electron injection layer 8 to a thickness of 1 nm. A magnesium-silver alloy was formed on this electron injection layer 8 as a cathode 9 to a thickness of 12 nm. Finally, a compound with the following structural formula (CPL-1) was formed as a capping layer 10 to a thickness of 60 nm. The fabricated organic EL element was subjected to a DC voltage in air at room temperature, resulting in a current density of 10 mA / cm². 2The measurement of the light emission characteristics when a current was passed was carried out, and the results are summarized in Table 2.

[0169] [Chemical formula]

[0170] [Chemical formula]

[0171] [Chemical formula]

[0172] [Chemical formula]

[0173] [Example 2] In Example 1, an organic EL device was fabricated under the same conditions except that compound (1-58) was used instead of compound (1-4) as the material of the second hole transport layer 5, and the measurement of the light emission characteristics was carried out in the same manner. The results are summarized in Table 2.

[0174] [Example 3] In Example 1, an organic EL device was fabricated under the same conditions except that compound (1-59) was used instead of compound (1-4) as the material of the second hole transport layer 5, and the measurement of the light emission characteristics was carried out in the same manner. The results are summarized in Table 2.

[0175] [Example 4] In Example 1, an organic EL device was fabricated under the same conditions except that compound (1-69) was used instead of compound (1-4) as the material of the second hole transport layer 5, and the measurement of the light emission characteristics was carried out in the same manner. The results are summarized in Table 2.

[0176] [Example 5] In Example 1, an organic EL element was fabricated under the same conditions as in Example 1, except that compound (1-83) was used instead of compound (1-4) as the material for the second hole transport layer 5. The luminescence characteristics were then measured in the same manner, and the results are summarized in Table 2.

[0177] [Example 6] In Example 1, an organic EL element was fabricated under the same conditions as in Example 1, except that compound (3-130) was used instead of compound (3-52) as the material for the hole injection layer 3 and the first hole transport layer 4. The luminescence characteristics were then measured in the same manner, and the results are summarized in Table 2.

[0178] [Example 7] In Example 2, an organic EL element was fabricated under the same conditions as in Example 2, except that compound (3-130) was used instead of compound (3-52) as the material for the hole injection layer 3 and the first hole transport layer 4. The luminescence characteristics were then measured in the same manner, and the results are summarized in Table 2.

[0179] [Example 8] In Example 3, an organic EL element was fabricated under the same conditions as in Example 3, except that compound (3-130) was used instead of compound (3-52) as the material for the hole injection layer 3 and the first hole transport layer 4. The luminescence characteristics were then measured in the same manner, and the results are summarized in Table 2.

[0180] [Example 9] In Example 4, an organic EL element was fabricated under the same conditions as in Example 4, except that compound (3-130) was used instead of compound (3-52) as the material for the hole injection layer 3 and the first hole transport layer 4. The luminescence characteristics were then measured in the same manner, and the results are summarized in Table 2.

[0181] [Example 10] In Example 5, an organic EL element was fabricated under the same conditions as in Example 5, except that compound (3-130) was used instead of compound (3-52) as the material for the hole injection layer 3 and the first hole transport layer 4. The luminescence characteristics were then measured in the same manner, and the results are summarized in Table 2.

[0182] [Example 11] In Example 1, an organic EL element was fabricated under the same conditions as in Example 1, except that compound (1-96) was used instead of compound (1-4) as the material for the second hole transport layer 5. The luminescence characteristics were then measured in the same manner, and the results are summarized in Table 2.

[0183] [Example 12] In Example 1, an organic EL element was fabricated under the same conditions as in Example 1, except that compound (1-97) was used instead of compound (1-4) as the material for the second hole transport layer 5. The luminescence characteristics were then measured in the same manner, and the results are summarized in Table 2.

[0184] [Example 13] In Example 1, an organic EL element was fabricated under the same conditions as in Example 1, except that compound (1-102) was used instead of compound (1-4) as the material for the second hole transport layer 5. The luminescence characteristics were then measured in the same manner, and the results are summarized in Table 2.

[0185] [Example 14] In Example 1, an organic EL element was fabricated under the same conditions as in Example 1, except that compound (1-103) was used instead of compound (1-4) as the material for the second hole transport layer 5. The luminescence characteristics were then measured in the same manner, and the results are summarized in Table 2.

[0186] [Example 15] In Example 11, an organic EL element was fabricated under the same conditions as in Example 11, except that compound (3-130) was used instead of compound (3-52) as the material for the hole injection layer 3 and the first hole transport layer 4. The luminescence characteristics were then measured in the same manner, and the results are summarized in Table 2.

[0187] [Example 16] In Example 12, an organic EL element was fabricated under the same conditions as in Example 12, except that compound (3-130) was used instead of compound (3-52) as the material for the hole injection layer 3 and the first hole transport layer 4. The luminescence characteristics were then measured in the same manner, and the results are summarized in Table 2.

[0188] [Example 17] In Example 13, an organic EL element was fabricated under the same conditions as in Example 13, except that compound (3-130) was used instead of compound (3-52) as the material for the hole injection layer 3 and the first hole transport layer 4. The luminescence characteristics were then measured in the same manner, and the results are summarized in Table 2.

[0189] [Example 18] In Example 14, an organic EL element was fabricated under the same conditions as in Example 14, except that compound (3-130) was used instead of compound (3-52) as the material for the hole injection layer 3 and the first hole transport layer 4. The luminescence characteristics were then measured in the same manner, and the results are summarized in Table 2.

[0190] [Comparative Example 1] For comparison, an organic EL element was fabricated under the same conditions as in Example 1, except that compound (HTM-1) was used instead of compound (3-52) for the hole injection layer 3 and the first hole transport layer 4, and compound (HTM-2) was used instead of compound (1-4) for the second hole transport layer 5. The luminescence characteristics were then measured in the same manner, and the results are summarized in Table 2.

[0191] [Comparative Example 2] For comparison, an organic EL element was fabricated under the same conditions as in Example 1, except that compound (HTM-1) was used instead of compound (3-52) for the hole injection layer 3 and the first hole transport layer 4, and compound (HTM-3) was used instead of compound (1-4) for the second hole transport layer 5. The luminescence characteristics were then measured in the same manner, and the results are summarized in Table 2.

[0192] [Comparative Example 3] For comparison, an organic EL element was fabricated under the same conditions as in Example 1, except that compound (HTM-1) was used instead of compound (3-52) as the material for the hole injection layer 3 and the first hole transport layer 4. The luminescence characteristics were then measured in the same manner, and the results are summarized in Table 2.

[0193] Table 1 summarizes the results of calculating the absolute difference between the HOMO level of the second hole transport layer and the HOMO level of the first hole transport layer for the elements of the examples and comparative examples. [Table 1]

[0194] As shown in Table 1, in Examples 1 to 18, the absolute value of the difference between the HOMO levels of the second hole transport layer and the first hole transport layer is 0.15 eV or less. On the other hand, in Comparative Examples 1 to 3, the absolute value of the difference between the HOMO levels of the second hole transport layer and the first hole transport layer is greater than 0.15 eV.

[0195] Table 2 summarizes the device lifetimes of the examples and comparative examples, with an initial luminescence brightness of 2000 cd / m². 2 When driven with a constant current, the luminescence brightness is 1900 cd / m². 2 This is the time it takes for the brightness to decay to 95% (equivalent to 95% of the initial brightness, which is set to 100%).

[0196] [Table 2]

[0197] As shown in Table 2, the current density is 10 mA / cm². 2 When the current was passed through, the voltage in Examples 1-18 was 3.45-3.50V, which is clearly lower than the 3.59-3.61V in Comparative Examples 1-3. Current density: 10mA / cm² 2 When a current was applied, the luminous efficiency in Examples 1-18 was 8.28-9.13 cd / A, which is clearly higher than the 7.23-7.97 cd / A of Comparative Examples 1-3. In terms of power efficiency, Examples 1-18 were 7.43-8.32 lm / W, which is clearly higher than the 6.30-6.98 lm / W of Comparative Examples 1-3. Furthermore, the element lifespan (95% decay) was significantly extended, from 244-323 hours for Comparative Examples 1-3 to 389-456 hours for Examples 1-18. [Industrial applicability]

[0198] The organic EL element using a triarylamine compound having a specific structure according to the present invention offers improved luminous efficiency and enhanced durability compared to conventional organic EL elements, enabling its application in, for example, home appliances and lighting. [Explanation of Symbols]

[0199] 1. Glass substrate 2 transparent anode 3. Hole injection layer 4 First hole transport layer 5 Second hole transport layer 6. Emitting layer 7 Electron transport layer 8 Electron injection layer 9 Cathode 10 Capping Layers

Claims

1. An organic electroluminescent element having at least a first hole transport layer, a second hole transport layer, a light-emitting layer, and an electron transport layer between the anode and cathode, in this order from the anode side, wherein the second hole transport layer contains a triarylamine compound represented by (1-96), (1-97), (1-102), or (1-103) below, the first hole transport layer contains a triarylamine compound represented by general formula (3), and the absolute value of the difference between the HOMO level of the second hole transport layer and the HOMO level of the first hole transport layer is 0.15 eV or less. 【Chemistry 1】 【Chemistry 2】 【Transformation 3】 (In the formula, D, E, and F each independently represent a group represented by the following general formula (4-1), a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted condensed polycyclic aromatic group, The substituents are aromatic hydrocarbon groups or fused polycyclic aromatic groups, and these groups may be further substituted with the substituents. However, the aromatic hydrocarbon group is a group selected from a phenyl group and a biphenylyl group, and the condensed polycyclic aromatic group is a group selected from a naphthyl group, a phenantrenyl group and a fluorenyl group. At least one of D, E, and F is represented by the following general formula (4-1), and q is a base of 1. 【Chemistry 4】 (In the formula, the dashed lines represent the joints, L ２ This represents a phenylene group that is substituted with or unsubstituted with a phenyl group. q represents 0 or 1, R ２ and R ３ This represents a deuterium atom, r represents an integer from 0 to 4, and s represents an integer from 0 to 3. X １ CR ５ R ６ This represents X １ They may be identical or different from one another. R ５ and R ６ each independently represents a linear alkyl group having 1 to 6 carbon atoms or an unsubstituted aromatic hydrocarbon group.)

2. The organic electroluminescent element according to claim 1, wherein the light-emitting layer contains a blue light-emitting dopant.

3. The organic electroluminescent element according to claim 2, wherein the blue light-emitting dopant is a compound represented by the following general formula (5-1) or (5-2). 【Transformation 5】 【Transformation 6】 (In equations (5-1) and (5-2), Q １ Q ２ and Q ３ Each of these independently represents a substituted or unsubstituted aromatic hydrocarbon or a substituted or unsubstituted aromatic heterocycle. X ２ This represents B, P, P=O or P=S, Y １ , Y ２ and Y ３ Each of them independently, N-R ７ , C-R ８ R ９ , O, S, Se or Si-R １０ R １１ This represents, R ７ , R ８ , R ９ , R １０ and R １１ Each independently represents a hydrogen atom, a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, a linear or branched alkyl group having 1 to 6 carbon atoms which may be substituted, a cycloalkyl group having 5 to 10 carbon atoms which may be substituted, a linear or branched alkenyl group having 2 to 6 carbon atoms which may be substituted, a linear or branched alkyloxy group having 1 to 6 carbon atoms which may be substituted, a cycloalkyloxy group having 5 to 10 carbon atoms which may be substituted, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, or a substituted or unsubstituted aryloxy group, R ８ and R ９ and R １０ and R １１ These may be bonded to each other via single bonds, substituted or unsubstituted methylene groups, oxygen atoms, sulfur atoms, or monosubstituted amino groups to form a ring. Y １ N-R ７ , C-R ８ R ９ or Si-R １０ R １１ In the case of R ７ , R ８ , R ９ , R １０ and R １１ Q １ They may also be bonded to each other via single bonds, substituted or unsubstituted methylene groups, oxygen atoms, sulfur atoms, or monosubstituted amino groups to form a ring. Y ２ N-R ７ , C-R ８ R ９ or Si-R １０ R １１ In the case of R ７ , R ８ , R ９ , R １０ and R １１ Q ２ Or Q ３ They may also be bonded to each other via single bonds, substituted or unsubstituted methylene groups, oxygen atoms, sulfur atoms, or monosubstituted amino groups to form a ring. Y ３ N-R ７ , C-R ８ R ９ or Si-R １０ R １１ In the case of R ７ , R ８ , R ９ , R １０ and R １１ Q ３ They may also be bonded to each other via single bonds, substituted or unsubstituted methylene groups, oxygen atoms, sulfur atoms, or monosubstituted amino groups to form a ring. However, the substituents are deuterium atoms, cyano groups, nitro groups, halogen atoms, silyl groups, linear or branched alkyl groups having 1 to 6 carbon atoms, linear or branched alkyloxy groups having 1 to 6 carbon atoms, alkenyl groups, aryloxy groups, arylalkyloxy groups, aromatic hydrocarbon groups, condensed polycyclic aromatic groups, or aromatic heterocyclic groups, and these substituents may be further substituted with the aforementioned substituents. Furthermore, benzene rings substituted with these substituents, or substituents multiple times substituted on the same benzene ring, may be bonded to each other via single bonds, substituted or unsubstituted methylene groups, substituted or unsubstituted amine groups, oxygen atoms, or sulfur atoms to form a ring.

4. The organic electroluminescent element according to any one of claims 1 to 3, wherein the light-emitting layer contains an anthracene derivative having an anthracene skeleton.

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