JP2004311424A - Organic electroluminescent element, lighting device and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminesent element having high luminescent efficiency and a lighting device and a display device using it. <P>SOLUTION: In the EL element having at least an emitting layer including phosphorescence compound and a hole transport layer, adjoining the emitting layer and including a hole transport material, 0-0 band of phosphorescence spectral of the hole transport material is 300nm to 450nm and its molecular weight is equal to or larger than 550. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an organic electroluminescent element, a lighting device, and a display device, and more particularly, to an organic electroluminescent device, a lighting device excellent in light emission luminance, light emitting efficiency, and durability, and a display device having the same.

  2. Description of the Related Art Conventionally, there is an electroluminescence display (ELD) as a light-emitting electronic display device. ELD includes an inorganic electroluminescence element and an organic electroluminescence element (hereinafter, also referred to as an organic EL element).

  Inorganic electroluminescent devices have been used as flat light sources, but require a high AC voltage to drive the light emitting devices.

  On the other hand, an organic EL element has a configuration in which a light-emitting layer containing a compound that emits light is sandwiched between a cathode and an anode, and electrons and holes are injected into the light-emitting layer and recombined to form excitons. And emits light by utilizing light emission (fluorescence / phosphorescence) when the exciton is deactivated. The element can emit light at a voltage of about several volts to several tens of volts. Since it is a light emitting type, it has a wide viewing angle and high visibility, and because it is a thin-film type solid-state element, it is attracting attention from the viewpoint of space saving and portability.

  As for the development of organic EL elements for practical use in the future, organic EL elements that emit light with high efficiency and low power consumption are desired. For example, stilbene derivatives, distyryl arylene derivatives or tris A technique of doping a styrylarylene derivative with a trace amount of a phosphor to improve emission luminance and extend the life of the device (see, for example, Patent Document 1), and using an 8-hydroxyquinoline aluminum complex as a host compound. A device having an organic light emitting layer doped with a small amount of phosphor (see, for example, Patent Document 2), and a device having an organic light emitting layer doped with a quinacridone-based dye using an 8-hydroxyquinoline aluminum complex as a host compound (for example, And Patent Document 3) are known.

  In the technique disclosed in the above-mentioned patent document, when light emission from an excited singlet is used, the generation ratio of a luminescent excited species is 25% because the generation ratio between a singlet exciton and a triplet exciton is 1: 3. And the light extraction efficiency is about 20%, so that the limit of the external extraction quantum efficiency (ηext) is 5%.

  However, since Princeton University reported an organic EL device using phosphorescence emission from an excited triplet (for example, see Non-Patent Document 1), research on materials exhibiting phosphorescence at room temperature has been active. (For example, see Non-Patent Document 2 and Patent Document 4).

  When the excited triplet is used, the upper limit of the internal quantum efficiency becomes 100%. Therefore, the luminous efficiency is quadrupled in principle as compared with the case of the excited singlet, and the performance almost equal to that of the cold cathode tube is obtained. It is also applicable to and is attracting attention.

  For example, many compounds have been studied for synthesis centering on heavy metal complexes such as iridium complexes (for example, see Non-Patent Document 3).

  Further, studies using tris (2-phenylpyridine) iridium as a dopant have been made (for example, see Non-Patent Document 2).

In addition, L ₂ Ir (acac), for example, (ppy) ₂ Ir (acac) (for example, see Non-Patent Document 4) as a dopant, and tris (2- (p-tolyl) pyridine) iridium ( A study using Ir (ptpy) ₃ ), tris (benzo [h] quinoline) iridium (Ir (bzq) ₃ ), Ir (bzq) ₂ ClP (Bu) _3, etc. (for example, see Non-Patent Document 5). Is being done.

  Further, in order to obtain high luminous efficiency, a hole transporting compound is used as a host of a phosphorescent compound (for example, see Non-Patent Document 6).

  In addition, various electron-transporting materials are used as a host of a phosphorescent compound by doping them with a novel iridium complex (for example, see Non-Patent Document 4). Further, high luminous efficiency is obtained by introducing a hole blocking layer (for example, see Non-Patent Document 5).

  At present, further enhancement of the efficiency of light emission and prolongation of life of the organic EL element using the phosphorescent light emission are being studied.

  However, for green light emission, although the external extraction efficiency of about 20%, which is the theoretical limit, is achieved, only the low current region (low luminance region) is reached, and the theoretical limit is still high in the high current region (high luminance region). Not achieved. In addition, sufficient efficiency has not yet been obtained for other luminescent colors, and improvement is necessary. In addition, in the organic EL device for practical use in the future, light emission with high efficiency and low power consumption is required. There is a demand for the development of an organic EL device. In particular, an organic EL device which emits blue phosphorescent light with high efficiency is required.

  Α-NPD, m-MTDATA, TPD, hm-TPD and PEDOT and PVK used in polymer systems are used as hole transporting materials for organic EL devices using conventional phosphorescence.

  Α-NPD, which is the most common, can easily inject holes into the light-emitting layer, but has low excited triplet energy and has sufficient performance as a hole-transporting material for a green phosphorescent organic EL device. As a matter of course, it does not have sufficient performance as a hole transport material of a blue phosphorescent organic EL device.

  m-MTDATA easily injects holes and has relatively high excited triplet energy, but does not have sufficient performance as a blue phosphorescent organic EL device. Similarly, TPD and hm-TPD (literature) are also unsuitable for blue phosphorescent devices and have a problem in terms of life.

  PEDOT has a very small excited triplet energy, and does not have sufficient performance as a hole transport material of a phosphorescent organic EL device. PVK is very good because it has a very high excited triplet energy. However, it has a very large ionization potential and still has a serious problem in terms of hole transportability (high driving voltage).

Naturally, even if these compounds are used, the layer structure is devised (adjustment of the film thickness and the injection balance of both charges) so that the triplet exciton is not deactivated by the hole transport layer. Although it can be done, it is very difficult, especially in the high current region (high brightness region).
Patent No. 3093796 JP-A-63-264692 JP-A-3-255190 U.S. Pat. No. 6,097,147 M. A. Baldo et al. , Nature, 395, 151-154 (1998) M. A. Baldo et al. , Nature, Vol. 403, No. 17, pp. 750-753 (2000) S. See Lamansky et al. , J. et al. Am. Chem. Soc. 123, 4304 pages (2001) M. E. FIG. Thompson et al. , The 10th International Works on Inorganic and Organic Electroluminescence (EL'00, Hamamatsu) Moon-Jae Youn. Og, Tetsuo Tsutsui et al. , The 10th International Works on Inorganic and Organic Electroluminescence (EL'00, Hamamatsu) Ikai et al. , The 10th International Works on Inorganic and Organic Electroluminescence (EL'00, Hamamatsu)

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an organic EL element, a lighting device, and a display device having high luminous efficiency.

  The above object of the present invention has been attained by the following constitutions 1 to 56.

(Claim 1)
In a light-emitting element having at least a light-emitting layer containing a phosphorescent compound and a hole-transport layer containing a hole-transport material adjacent to the light-emitting layer,
The organic electroluminescent device, wherein the hole transporting material has a 0-0 band in a phosphorescence spectrum of 300 nm to 450 nm and a molecular weight of 550 or more.

(Claim 2)
The organic electroluminescence device according to claim 1, wherein the hole transport material has an ionization potential Ip1 (eV) of 5.00 to 5.70 eV.

(Claim 3)
The organic electroluminescent device according to claim 1, wherein the ionization potential Ip1 (eV) of the hole transport material and the ionization potential Ip3 (eV) of the phosphorescent compound satisfy the following expression.

−0.1 eV ≦ Ip3-Ip1 ≦ 0.5 eV
(Claim 4)
4. The electron affinity Ea1 (eV) of the hole transport material and the excited triplet level T3 (eV) of the phosphorescent compound satisfy the following expression. The organic electroluminescent device according to the above.

0.5 eV <T3-Ea1 <1.3 eV
(Claim 5)
The organic electroluminescence device according to any one of claims 1 to 4, wherein the phosphorescent compound has a phosphorescent maximum emission wavelength in a range from 380 nm to 480 nm.

(Claim 6)
A hole transporting layer adjacent to the hole transporting layer and opposite to the light emitting layer, wherein an ionization potential Ip4 (eV) of a hole transporting material contained in the hole transporting layer and the hole The organic electroluminescence device according to any one of claims 1 to 5, wherein the ionization potential Ip1 (eV) of the transport material satisfies the following expression.

0.1 eV <Ip1-Ip4 <0.7 eV
(Claim 7)
The organic electroluminescent device according to claim 6, wherein the thickness of the hole transport layer adjacent to the light emitting layer is 5 nm to 20 nm.

(Claim 8)
The organic electroluminescent device according to any one of claims 1 to 7, wherein the light emitting layer further contains a host compound.

(Claim 9)
The organic electroluminescence device according to claim 8, wherein the ionization potential Ip1 (eV) of the hole transport material and the ionization potential Ip2 (eV) of the host compound satisfy the following expression.

0.3 eV <Ip2-Ip1 <1.0 eV
(Claim 10)
10. The organic electroluminescence device according to claim 8, wherein the electron affinity Ea1 (eV) of the hole transport material and the electron affinity Ea2 (eV) of the host compound satisfy the following expression.

0.1 eV <Ea2-Ea1 <0.8 eV
(Claim 11)
The organic electroluminescent device according to any one of claims 8 to 10, wherein the 0-0 band of the phosphorescence spectrum of the host compound is from 300 nm to 450 nm.

(Claim 12)
The organic electroluminescence device according to claim 8, wherein the host compound is a carbazole derivative.

(Claim 13)
13. The organic electroluminescent device according to claim 12, wherein the carbazole derivative is a compound represented by the following general formula 11.

(In the formula, R _{1001 to} R ₁₀₁₃ each independently represent a hydrogen atom or a substituent, but at least one represents a substituent.)
(Claim 14)
13. The organic electroluminescence device according to claim 12, wherein the carbazole derivative is a compound represented by the following general formula 12.

(In the formula, R ₁₀₂₁ represents an alkyl group, a cycloalkyl group, or a fluorinated alkyl group, and R _{1022 to} R ₁₀₂₉ each independently represent a hydrogen atom or a substituent. Represents.)
(Claim 15)
13. The organic electroluminescent device according to claim 12, wherein the carbazole derivative is a compound represented by the following general formula 13.

(Wherein, R _{1031 to} R ₁₀₄₆ each independently represent a hydrogen atom or a substituent, and L ₃ represents a divalent linking group or a direct bond. In the case of a direct bond, R ₁₀₃₇ and R ₁₀₃₈ , R ₁₀₄₅ or R ₁₀₄₆ represents a substituent.)
(Claim 16)
The organic electroluminescent device according to claim 12, wherein the carbazole derivative is a compound represented by the following general formula 14.

(In the formula, R _{1051 to} R ₁₀₆₃ each independently represent a hydrogen atom or a substituent, and any of R ₁₀₅₇ , R ₁₀₅₈ , R ₁₀₆₂ , and R ₁₀₆₃ represents a substituent.)
(Claim 17)
The organic electroluminescent device according to claim 12, wherein the carbazole derivative is a compound represented by the following general formula 15.

(Wherein, R _{1071 to} R ₁₀₇₉ each independently represent a hydrogen atom or a substituent, and either R ₁₀₇₂ or R ₁₀₇₃ represents a substituent. N represents an integer of 1 to 8. )
(Claim 18)
The organic electroluminescent device according to any one of claims 1 to 17, wherein the hole transport material is a triarylamine compound.

(Claim 19)
The organic electroluminescent device according to claim 18, wherein the triarylamine compound is a compound represented by the following general formula 1.

(In the formula, Ar _{11 to} Ar ₁₃ each represent an arylene group or a heteroarylene group. R _{11 to} R ₁₃ each independently represent a hydrogen atom or a substituent, and at least one represents a substituent. .)
(Claim 20)
The organic electroluminescence device according to claim 18, wherein the triarylamine compound is a compound represented by the following general formula 2.

(In the formula, Ar ₃₀₁ represents an aryl group or a heteroaryl group which may have a substituent, B represents the following general formula 3, and n represents an integer of 1 to 3.)

(Wherein, Z ₁ and Z ₂ each independently represent an atomic group necessary for forming an aromatic carbocyclic ring or an aromatic heterocyclic ring, and X _{1 to} X ₄ each independently represent C It represents -R _301, N, O, S, a, R ₃₀₁ represents a hydrogen atom, or represents a substituent, at least one of X ₁ to X ₄ represents a C-R _301, R ₃₀₁ at that time Represents a substituent.)
(Claim 21)
The organic electroluminescence device according to claim 18, wherein the triarylamine compound is at least one of compounds represented by the following general formulas 4-1 and 4-2.

(Wherein, Ar _{801 to} Ar ₈₀₃ each represent an aryl group or a heteroaryl group which may have a substituent. R _{801 to} R ₈₂₇ each represent a hydrogen atom or a substituent; provided that R ₈₀₁ and R ₈₀₂ are each a substituent. Is a substituent, any of R ₈₀₃ and R ₈₀₄ is a substituent, and any of R ₈₀₅ and R ₈₀₆ is a substituent; any of R _{807 to} R ₈₁₀ is a substituent; and R _{811 to} R ₈₁₄ Is a substituent, and any of R _{815 to} R ₈₁₈ represents a substituent.)
(Claim 22)
19. The organic electroluminescent device according to claim 18, wherein the triarylamine compound is at least one of the compounds represented by the following general formula 5.

(Wherein, R _{960 to} R ₉₇₆ each independently represent a hydrogen atom or a substituent. However, any of R ₉₆₀ and R ₉₆₁ represents a substituent, and any of R ₉₆₃ and R ₉₆₄ represents a substituent. L ₁ represents a divalent linking group or a direct bond)
(Claim 23)
19. The organic electroluminescent device according to claim 18, wherein the triarylamine compound is at least one of the compounds represented by the following general formula 6.

(In the formula, R _{960 to} R ₉₇₆ each independently represent a hydrogen atom or a substituent. L ₂ represents a divalent alkylene group, a cycloalkylene group, or a fluorinated alkylene group.)
(Claim 24)
19. The organic electroluminescent device according to claim 18, wherein the triarylamine compound is at least one of the compounds represented by the following general formula 7.

(In the formula, B ₂ represents the following general formula 8, and Ar _{501 to} Ar ₅₀₃ each independently represent an aryl group or a heteroaryl group which may have a substituent. N is an integer of 1 to 3. Represent)

(Wherein, X _{5 to} X ₈ each independently represent N or C—R ₅₀₁ , and R ₅₀₁ represents a hydrogen atom or a substituent. At least one of X ₅ and X ₆ represents C— R ₅₀₁ , at least one of R ₅₀₁ represents a substituent, and at least one of X ₇ and X ₈ is _{CR 501} , and at least one of R ₅₀₁ represents a substituent.)
(Claim 25)
19. The organic electroluminescent device according to claim 18, wherein the triarylamine compound is at least one of the compounds represented by the following general formula 9.

(Wherein, R _{833 to} R ₈₇₄ each independently represent a hydrogen atom or a substituent. However, one of R ₈₃₃ and R ₈₃₄ represents a substituent, and one of R ₈₃₅ and R _{836 Represents} a substituent, one of R ₈₃₇ and R ₈₃₈ represents a substituent, one of R ₈₃₉ and R ₈₄₀ represents a substituent, and one of R ₈₄₁ and R ₈₄₂ represents a substituent. , R ₈₄₃ or R ₈₄₄ represents a substituent.)
(Claim 26)
The organic electroluminescence according to claim 18, wherein the triarylamine compound has at least one of terminal groups represented by the following general formulas 10-1, 10-2, 10-3, and 10-4. element.

(Wherein X ₉ and X ₁₀ each independently represent N, O, S, or C—R ₆₁₁ , and R ₆₁₁ represents a hydrogen atom or a substituent, and at least X ₉ and X ₁₀ One is C-R ₆₁₁ , wherein R ₆₁₁ is a substituent, and Z ₆₀₁ represents an atom group necessary for forming an aromatic carbon ring or an aromatic hetero ring together with X ₉ and X _10. R _{601 to} R ₆₀₅ each independently represent a hydrogen atom or a substituent, and at least one of R ₆₀₁ and R ₆₀₅ is a substituent, and R _{606 to} R ₆₁₀ each independently represent a substituent. .)
(Claim 27)
In a light-emitting element having at least a light-emitting layer containing a phosphorescent compound and a hole-transport layer containing a hole-transport material adjacent to the light-emitting layer,
The organic electroluminescent device, wherein the hole transport material is a triarylamine compound represented by the following general formula 1.

(In the formula, Ar _{11 to} Ar ₁₃ each represent an arylene group or a heteroarylene group. R _{11 to} R ₁₃ each independently represent a hydrogen atom or a substituent, and at least one represents a substituent. .)
(Claim 28)
In a light-emitting element having at least a light-emitting layer containing a phosphorescent compound and a hole-transport layer containing a hole-transport material adjacent to the light-emitting layer,
The organic electroluminescent device, wherein the hole transport material is a triarylamine compound represented by the following general formula 2.

(In the formula, Ar ₃₀₁ represents an aryl group or a heteroaryl group which may have a substituent, B represents the following general formula 3, and n represents an integer of 1 to 3.)

(Wherein, Z ₁ and Z ₂ each independently represent an atomic group necessary for forming an aromatic carbocyclic ring or an aromatic heterocyclic ring, and X _{1 to} X ₄ each independently represent C It represents -R _301, N, O, S, a, R ₃₀₁ represents a hydrogen atom, or represents a substituent, at least one of X ₁ to X ₄ represents a C-R _301, R ₃₀₁ at that time Represents a substituent.)
(Claim 29)
In a light-emitting element having at least a light-emitting layer containing a phosphorescent compound and a hole-transport layer containing a hole-transport material adjacent to the light-emitting layer,
An organic electroluminescent device, wherein the hole transporting material is at least one of triarylamine compounds represented by the following general formulas 4-1 and 4-2.

(Wherein, Ar _{801 to} Ar ₈₀₃ each represent an aryl group or a heteroaryl group which may have a substituent. R _{801 to} R ₈₂₇ each represent a hydrogen atom or a substituent; provided that R ₈₀₁ and R ₈₀₂ are each a substituent. Is a substituent, any of R ₈₀₃ and R ₈₀₄ is a substituent, and any of R ₈₀₅ and R ₈₀₆ is a substituent; any of R _{807 to} R ₈₁₀ is a substituent; and R _{811 to} R ₈₁₄ Is a substituent, and any of R _{815 to} R ₈₁₈ represents a substituent.)
(Claim 30)
In a light-emitting element having at least a light-emitting layer containing a phosphorescent compound and a hole-transport layer containing a hole-transport material adjacent to the light-emitting layer,
An organic electroluminescent device, wherein the hole transport material is a triarylamine compound represented by the following general formula 5.

(Wherein, R _{960 to} R ₉₇₆ each independently represent a hydrogen atom or a substituent. However, any of R ₉₆₀ and R ₉₆₁ represents a substituent, and any of R ₉₆₃ and R ₉₆₄ represents a substituent. L ₁ represents a divalent linking group or a direct bond)
(Claim 31)
In a light-emitting element having at least a light-emitting layer containing a phosphorescent compound and a hole-transport layer containing a hole-transport material adjacent to the light-emitting layer,
An organic electroluminescent device, wherein the hole transport material is a triarylamine compound represented by the following general formula 6.

(In the formula, R _{960 to} R ₉₇₆ each independently represent a hydrogen atom or a substituent. L ₂ represents a divalent alkylene group, a cycloalkylene group, or a fluorinated alkylene group.)
(Claim 32)
In a light-emitting element having at least a light-emitting layer containing a phosphorescent compound and a hole-transport layer containing a hole-transport material adjacent to the light-emitting layer,
The organic electroluminescent device, wherein the hole transport material is a triarylamine compound represented by the following general formula 7.

(In the formula, B ₂ represents the following general formula 8, and Ar _{501 to} Ar ₅₀₃ each independently represent an aryl group or a heteroaryl group which may have a substituent. N is an integer of 1 to 3. Represent)

(Wherein, X _{5 to} X ₈ each independently represent N or C—R ₅₀₁ , and R ₅₀₁ represents a hydrogen atom or a substituent. At least one of X ₅ and X ₆ represents C— R ₅₀₁ , at least one of R ₅₀₁ represents a substituent, and at least one of X ₇ and X ₈ is _{CR 501} , and at least one of R ₅₀₁ represents a substituent.)
(Claim 33)
In a light-emitting element having at least a light-emitting layer containing a phosphorescent compound and a hole-transport layer containing a hole-transport material adjacent to the light-emitting layer,
The organic electroluminescent device, wherein the hole transport material is a triarylamine compound represented by the following general formula 9.

(Wherein, R _{833 to} R ₈₇₄ each independently represent a hydrogen atom or a substituent. However, one of R ₈₃₃ and R ₈₃₄ represents a substituent, and one of R ₈₃₅ and R _{836 Represents} a substituent, one of R ₈₃₇ and R ₈₃₈ represents a substituent, one of R ₈₃₉ and R ₈₄₀ represents a substituent, and one of R ₈₄₁ and R ₈₄₂ represents a substituent. , R ₈₄₃ or R ₈₄₄ represents a substituent.)
(Claim 34)
In a light-emitting element having at least a light-emitting layer containing a phosphorescent compound and a hole-transport layer containing a hole-transport material adjacent to the light-emitting layer,
The organic electroluminescence, wherein the hole transport material is a triarylamine compound having at least one of terminal groups represented by the following general formulas 10-1, 10-2, 10-3, and 10-4. element.

(Wherein X ₉ and X ₁₀ each independently represent N, O, S, or C—R ₆₁₁ , and R ₆₁₁ represents a hydrogen atom or a substituent, and at least X ₉ and X ₁₀ One is C-R ₆₁₁ , wherein R ₆₁₁ is a substituent, and Z ₆₀₁ represents an atom group necessary for forming an aromatic carbon ring or an aromatic hetero ring together with X ₉ and X _10. R _{601 to} R ₆₀₅ each independently represent a hydrogen atom or a substituent, and at least one of R ₆₀₁ and R ₆₀₅ is a substituent, and R _{606 to} R ₆₁₀ each independently represent a substituent. .)
(Claim 35)
The organic electroluminescent device according to any one of claims 27 to 34, wherein the hole transport material has a molecular weight of 550 or more.

(Claim 36)
The organic electroluminescence device according to any one of claims 27 to 35, wherein the hole transport material has an ionization potential Ip1 (eV) of 5.00 to 5.70 eV.

(Claim 37)
37. The organic electroluminescent device according to claim 27, wherein the ionization potential Ip1 (eV) of the hole transport material and the ionization potential Ip3 (eV) of the phosphorescent compound satisfy the following expression. Luminescent element.

−0.1 eV ≦ Ip3-Ip1 ≦ 0.5 eV
(Claim 38)
The electron affinity Ea1 (eV) of the hole transporting material and the excited triplet level T3 (eV) of the phosphorescent compound satisfy the following expression. The organic electroluminescent device according to the above.

0.5 eV <T3-Ea1 <1.3 eV
(Claim 39)
The organic electroluminescence device according to any one of claims 27 to 38, wherein the phosphorescent compound has a phosphorescent maximum emission wavelength at 380 to 480 nm.

(Claim 40)
A hole transporting layer adjacent to the hole transporting layer and opposite to the light emitting layer, wherein an ionization potential Ip4 (eV) of a hole transporting material contained in the hole transporting layer and the hole The organic electroluminescence device according to any one of claims 27 to 39, wherein the ionization potential Ip1 (eV) of the transport material satisfies the following expression.

0.1 eV <Ip1-Ip4 <0.7 eV
(Claim 41)
41. The organic electroluminescence device according to claim 40, wherein the thickness of the hole transport layer adjacent to the light emitting layer is 5 nm to 20 nm.

(Claim 42)
The organic electroluminescence device according to any one of claims 27 to 41, wherein the light emitting layer further contains a host compound.

(Claim 43)
The organic electroluminescence according to any one of claims 27 to 42, wherein an ionization potential Ip1 (eV) of the hole transport material and an ionization potential Ip2 (eV) of the host compound satisfy the following expression. element.

0.3 eV <Ip2-Ip1 <1.0 eV
(Claim 44)
The organic electroluminescence according to any one of claims 27 to 43, wherein an electron affinity Ea1 (eV) of the hole transport material and an electron affinity Ea2 (eV) of the host compound satisfy the following expression. element.

0.1 eV <Ea2-Ea1 <0.8 eV
(Claim 45)
The organic electroluminescent device according to any one of claims 27 to 44, wherein the 0-0 band of the phosphorescence spectrum of the host compound is from 300 nm to 450 nm.

(Claim 46)
The organic electroluminescent device according to any one of claims 27 to 45, wherein the host compound is a carbazole derivative.

(Claim 47)
47. The organic electroluminescent device according to claim 46, wherein the carbazole derivative is a compound represented by the following general formula 11.

(In the formula, R _{1001 to} R ₁₀₁₃ each independently represent a hydrogen atom or a substituent, but at least one represents a substituent.)
(Claim 48)
47. The organic electroluminescent device according to claim 46, wherein the carbazole derivative is a compound represented by the following general formula 12.

(In the formula, R ₁₀₂₁ represents an alkyl group, a cycloalkyl group, or a fluorinated alkyl group, and R _{1022 to} R ₁₀₂₉ each independently represent a hydrogen atom or a substituent. Represents.)
(Claim 49)
47. The organic electroluminescent device according to claim 46, wherein the carbazole derivative is a compound represented by the following general formula 13.

(Wherein, R _{1031 to} R ₁₀₄₆ each independently represent a hydrogen atom or a substituent, and L ₃ represents a divalent linking group or a direct bond. In the case of a direct bond, R ₁₀₃₇ and R ₁₀₃₈ , R ₁₀₄₅ or R ₁₀₄₆ represents a substituent.)
(Claim 50)
47. The organic electroluminescent device according to claim 46, wherein the carbazole derivative is a compound represented by the following general formula 14.

(In the formula, R _{1051 to} R ₁₀₆₃ each independently represent a hydrogen atom or a substituent, and any of R ₁₀₅₇ , R ₁₀₅₈ , R ₁₀₆₂ , and R ₁₀₆₃ represents a substituent.)
(Claim 51)
47. The organic electroluminescent device according to claim 46, wherein the carbazole derivative is a compound represented by the following general formula 15.

(Wherein, R _{1071 to} R ₁₀₇₉ each independently represent a hydrogen atom or a substituent, and either R ₁₀₇₂ or R ₁₀₇₃ represents a substituent. N represents an integer of 1 to 8. )
(Claim 52)
The organic electroluminescence device according to any one of claims 1 to 51, wherein the hole transport layer is formed by vapor deposition.

(Claim 53)
The organic electroluminescent device according to any one of claims 1 to 51, wherein the hole transport layer is formed by a wet process.

(Claim 54)
A display device comprising the organic electroluminescence device according to claim 1.

(Claim 55)
An illumination device comprising the organic electroluminescence element according to claim 1.

(Claim 56)
A display device comprising: the lighting device according to claim 55; and a liquid crystal element as a display unit.

  According to the present invention, an organic EL element, a lighting device, and a display device having high luminous efficiency can be provided.

  In the organic electroluminescence device of the present invention, by adopting the configuration defined in any one of claims 1 to 13, an organic EL device having high luminous efficiency was obtained. In addition, the display device according to claim 54 or 56, the lighting device according to claim 55, and the like having high luminance can be obtained by using the organic EL element.

  Hereinafter, details of each component according to the present invention will be sequentially described.

  The present inventors have conducted intensive studies and found that a light-emitting element having at least a light-emitting layer containing a phosphorescent compound and a hole-transport layer containing a hole-transport material adjacent to the light-emitting layer, It has been found that when the 0-0 band of the phosphorescence spectrum of the transport material is 300 nm to 450 nm and the molecular weight is 550 or more, thermal stability can be improved and luminous efficiency can be increased. That is, the present inventors have found that the light emission of the organic EL element is caused not only by the recombination of the electron-hole (hole) on the cathode side in the light emitting layer, but also by the actual hole transport in the light emitting layer. It has been found that the light-emitting layer may be formed on the layer side, and by using a hole-transporting material having a 0-0 band in the phosphorescence spectrum of 300 nm to 450 nm and a molecular weight of 550 or more for the hole-transporting layer, It has been found that recombination of electrons-holes (holes) on the side of the hole transport layer in the medium can be performed efficiently, thereby improving luminous efficiency and improving thermal stability.

  By using a hole transporting material having a 0-0 band in the phosphorescence spectrum of 300 nm to 450 nm and a molecular weight of 550 or more in the hole transporting layer adjacent to the light emitting layer, the excited triplet energy can be increased. In this way, the triplet exciton can be confined to enhance the luminous efficiency and further improve the thermal stability. In particular, a remarkable effect can be obtained in a phosphorescent light emission or a blue phosphorescent light emitting element in a high current region.

  The 0-0 band of the phosphorescence spectrum can be determined by the following measurement method.

  The compound to be measured is dissolved in a well-deoxygenated mixed solvent of ethanol / methanol = 4/1 (vol / vol), placed in a cell for phosphorescence measurement, and then irradiated with excitation light at a liquid nitrogen temperature of 77 K. The emission spectrum at 100 ms after irradiation is measured. Since the phosphorescent light has a longer emission lifetime than the fluorescence, the light remaining after 100 ms can be considered to be almost phosphorescent light. The measurement may be performed with a shorter delay time for a compound having a phosphorescence life shorter than 100 ms. However, if the delay time is so shortened that it cannot be distinguished from fluorescence, phosphorescence and fluorescence cannot be separated. Since it causes a problem, it is necessary to select a delay time capable of separating the delay time.

  For a compound that cannot be dissolved in the above-mentioned solvent system, any solvent that can dissolve the compound may be used (substantially, there is no problem because the solvent effect of the phosphorescence wavelength is very small in the above-mentioned measurement method).

  Next, regarding the method of obtaining the 0-0 band, in the present invention, the 0-0 band is defined as the emission maximum wavelength that appears on the shortest wavelength side in the phosphorescence spectrum chart obtained by the above measurement method.

  Since the intensity of a phosphorescent spectrum is usually low, it is sometimes difficult to distinguish between a noise and a peak when the spectrum is enlarged. In such a case, the stationary light spectrum is enlarged and superimposed on the emission spectrum 100 ms after the excitation light irradiation (for convenience, this is called a phosphorescence spectrum), and the peak wavelength is read from the stationary light spectrum portion derived from the phosphorescence spectrum. Can be determined. Further, by performing a smoothing process on the phosphorescent spectrum, noise and a peak can be separated and the peak wavelength can be read. As the smoothing process, a Savitzky & Golay smoothing method or the like can be applied.

In the present invention, the 0-0 band of the phosphorescent spectrum is from 300 nm to 450 nm, more preferably from 350 nm to 430 nm. Thereby, the luminous efficiency can be further enhanced. As such a hole transport material, a triarylamine compound is preferable.

  Among the triaryl compounds, the following triarylamine compounds are preferable, whereby the luminous efficiency can be further improved.

  First, a triaryl compound represented by the general formula 1 can be mentioned.

In the general formula 1, as a substituent represented by R _{11 to} R ₁₃ , an alkyl group (for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group, Dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, etc., cycloalkyl group (eg, cyclopentyl group, cyclohexyl group, etc.), alkenyl group (eg, vinyl group, allyl group, etc.), alkynyl group (eg, ethynyl group, propargyl group) Group), an aryl group (eg, phenyl group, biphenylyl group, etc.), a heteroaryl group (eg, furyl group, thienyl group, pyridyl group, pyridazinyl group, pyrimidinyl group, pyrazinyl group, triazinyl group, imidazolyl group, pyrazolyl group, Thiazolyl group, carbazolyl group, etc.), heterocyclic group (for example, Loridyl group, imidazolidyl group, morpholyl group, oxazolidyl group, etc.), alkoxy group (for example, methoxy group, ethoxy group, propyloxy group, pentyloxy group, hexyloxy group, octyloxy group, dodecyloxy group, etc.), cycloalkoxy group (Eg, cyclopentyloxy group, cyclohexyloxy group, etc.), aryloxy group (eg, phenoxy group, naphthyloxy group, etc.), alkylthio group (eg, methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group) , Dodecylthio, etc.), cycloalkylthio (eg, cyclopentylthio, cyclohexylthio, etc.), arylthio (eg, phenylthio, naphthylthio, etc.), alkoxycarbonyl (eg, methyloxy Rubonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc., aryloxycarbonyl group (eg, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), sulfamoyl group (eg, amino Sulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2- Pyridylaminosulfonyl group, etc.), acyl group (eg, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexyl) Rubonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy group (for example, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, Octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc., amide group (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino Group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonyl Carbamoyl group (eg, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group) , Dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), ureido group (for example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido group, dodecyl) Ureido group, phenylureido group, naphthylureido group, 2-pyridylaminoureido group, etc.), sulfinyl group (for example, methylsulfinyl group, ethylsulfinyl group) Group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group and the like, alkylsulfonyl group (for example, methylsulfonyl group, ethylsulfonyl group, Butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc., arylsulfonyl group (phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (eg, amino group, ethylamino Group, dimethylamino group, butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, naphthylamino group, 2-pyridylamino group ), A halogen atom (eg, a fluorine atom, a chlorine atom, a bromine atom, etc.), a fluorinated hydrocarbon group (eg, a fluoromethyl group, a trifluoromethyl group, a pentafluoroethyl group, a pentafluorophenyl group, etc.), a cyano group, Examples include a nitro group, a hydroxy group, a mercapto group, and a silyl group (for example, a trimethylsilyl group, a triisopropylsilyl group, a triphenylsilyl group, a phenyldiethylsilyl group, and the like).

  These substituents may be further substituted by the above-mentioned substituents. In addition, these substituents include substituents which may be bonded to each other to form a ring. However, only the substituent is important, and the 0-0 band of the phosphorescence spectrum is 450 nm or less. Certain groups with low excited triplet energy are preferred.

  For example, the phenyl group has a 0-0 band in the phosphorescence spectrum of 400 nm or less and is preferably used as a substituent.

Among the substituents represented by R _{11 to} R ₁₃ , an alkyl group, a cycloalkyl group, a fluorinated hydrocarbon group, an aryl group, and a heteroaryl group are particularly preferably used.

When R _{11 to} R ₁₃ represent an aryl group or a heteroaryl group, the aryl group is preferably, for example, a phenyl group, and the heteroaryl group is a furyl group, a thienyl group, a pyridyl group, a pyridazinyl group, a pyrimidinyl group, Pyrazinyl, triazinyl, imidazolyl, pyrazolyl, thiazolyl, carbazolyl and the like are preferred.

  Similarly, a group having a large excited triplet energy such that only the aryl group or the heteroaryl group has a 0-0 band of 450 nm or less in a phosphorescence spectrum is preferable.

In the general formula 1, examples of the arylene group represented by each of Ar _{11 to} Ar ₁₃ include a phenylene group (for example, an o-phenylene group, an m-phenylene group, a p-phenylene group, and the like), and a biphenyldiyl group (for example, [1,1'-biphenyl] -4,4'-diyl group, 3,3'-biphenyldiyl group, 3,6-biphenyldiyl group and the like. Further, the arylene group may have a substituent represented by each of the above R _{11 to} R ₁₃ .

In the general formula 1, examples of the heteroarylene group represented by Ar _{11 to} Ar ₁₃ include, for example, a furan ring, a carbazole ring, a triazole ring, a pyrrole ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazine ring, an imidazole ring, A pyrazole ring, a thiazole ring, a thiophene ring, an oxadiazole ring, a dibenzofuran ring, a dibenzothiophene ring, a divalent group derived from the group consisting of an indole ring, and the like, and the heteroarylene group is, It may have a substituent represented by R _{11 to} R ₁₃ .

In the general formula 1, as for the arylene group and the heteroarylene group represented by Ar _{11 to} Ar ₁₃ , similarly to the substituent represented by the above R _{11 to} R ₁₃ , the arylene group or the heteroarylene group alone may be used. The 0-0 band of the phosphorescence spectrum is preferably 450 nm or less.

The dihedral angle of Ar ₁₁ to Ar ₁₃ connected to the aryl group or heteroaryl group of R _{11 to} R ₁₃ is preferably 50 degrees or more. This can be sterically controlled by introducing a substituent into Ar _{11 to} Ar ₁₃ or R _{11 to} R ₁₃ . When three-dimensional control is not performed without introducing a substituent, the dihedral angle is generally 50 degrees or less. In such a state, as the conjugate length is extended, the 0-0 band of the phosphorescence spectrum tends to have a longer wavelength and the excited triplet energy tends to be smaller.

  The dihedral angle refers to the angle between the directly connected aromatic ring plane and the directly connected aromatic ring plane by optimizing the structure in the ground state by molecular orbital calculation (for example, MOPAC, gaussian) of the compound.

  Next, a compound represented by the general formula 2 is exemplified.

In the general formula 2, Ar ₃₀₁ represents an aryl group or a heteroaryl group which may have a substituent, B represents the general formula 3, and n represents an integer of 1 to 3.

In the general formula 3, Z ₁ and Z ₂ each independently represent an atomic group required to form an aromatic carbocyclic ring or an aromatic heterocyclic ring, and X _{1 to} X ₄ each independently represent , _{CR 301} , N, O, S, wherein R ₃₀₁ represents a hydrogen atom or a substituent, and at least one of X _{1 to} X ₄ represents CR ₃₀₁ ; R ₃₀₁ represents a substituent. At least one of X _{1 to} X ₄ represents C—R ₃₀₁ , and R ₃₀₁ is a substituent, so that steric repulsion occurs and a dihedral angle of 50 ° or more is achieved.

  Next, the compounds represented by the general formulas 4-1 and 4-2 are exemplified.

In the general formulas 4-1 and 4-2, R _{801 to} R ₈₂₇ represent a hydrogen atom or a substituent. However, any of R ₈₀₁ and R ₈₀₂ is a substituent, any of R ₈₀₃ and R ₈₀₄ is a substituent, any of R ₈₀₅ and R ₈₀₆ is a substituent, and any of R _{807 to} R ₈₁₀ is a substituent. And any one of R _{811 to} R ₈₁₄ represents a substituent, and any of R _{815 to} R ₈₁₈ represents a substituent. By having such a substituent, a dihedral angle of 50 ° or more can be achieved. In particular, the central skeleton is preferably triphenylamine, and more preferably a phenyl group which may have a substituent as an aryl group to be linked. Here, it is preferable that each phenyl group has a substituent at the m-position and the P-position. By having a substituent in this portion, a higher excited triplet energy can be obtained, and the stability of the compound is also improved.

  Next, a compound represented by the general formula 5 is exemplified.

In Formula 5, R _{960 to} R ₉₇₆ each independently represent a hydrogen atom or a substituent. However, any of R ₉₆₀ and R ₉₆₁ represents a substituent, and any of R ₉₆₃ and R ₉₆₄ represents a substituent. L ₁ represents a divalent linking group or a direct bond, and is preferably an alkylene group, a cycloalkylene group, a fluorinated alkylene group, an arylene group, or a heteroarylene group.

Examples of the alkylene group represented by L ₁ include an ethylene group, a trimethylene group, a tetramethylene group, a propylene group, an ethylethylene group, a pentamethylene group, a hexamethylene group, a 2,2,4-trimethylhexamethylene group, Examples include a methylene group, an octamethylene group, a nonamethylene group, a decamethylene group, an undecamethylene group, and a dodecamethylene group.

Examples of the cycloalkylene group represented by L ₁ include a cyclohexylene group (eg, a 1,6-cyclohexanediyl group), a cyclopentylene group (eg, a 1,5-cyclopentanediyl group). Can be

Examples of the arylene group represented by L ₁ include an o-phenylene group, an m-phenylene group, a p-phenylene group, and a biphenyldiyl group (for example, a 3,3′-biphenyldiyl group, a 3,6-biphenyldiyl group). And the like. Further, the arylene group may further have a substituent represented by each of R _{1 to} R ₄ .

The heteroarylene group represented by L _1, for example, furan ring, a carbazole ring, a triazole ring, pyrrole ring, pyridine ring, pyrazine ring, a pyrimidine ring, a triazine ring, an imidazole ring, a pyrazole ring, a thiazole ring, a quinoxaline ring, And a divalent group derived from the group consisting of a thiophene ring, an oxadiazole ring, a dibenzofuran ring, a dibenzothiophene ring, and an indole ring.

Each group represented by the above L ₁ may have a substituent group represented by R ₁₁ to R _13.

Also here, similarly, there is no need for a substituent at the o-position of triphenylamine, and when L _{1 to} be further linked is an arylene or a heteroarylene, conjugation is connected. Therefore, steric control is effected by R _{960 to} R _964. In order to achieve this, it is preferable to have any substituent.

  Next, a compound represented by the general formula 6 is exemplified.

In Formula 6, R _{960 to} R ₉₇₆ each independently represent a hydrogen atom or a substituent. L ₂ represents a divalent alkylene group, a cycloalkylene group, a linking group such as a fluorinated alkylene group, but by using a non-conjugated linking group as a linking group, a substituent for steric control is do not need. In the present invention, similar effects can be obtained by using a non-conjugated linking group. However, it is not necessary to introduce a substituent at the 2,6-position of triphenylamine for the same reason as described above.

  Next, a compound represented by the general formula 7 is exemplified.

In the general formula 7, B ₂ represents the general formula 8, and Ar _{501 to} Ar ₅₀₃ each independently represent an aryl group or a heteroaryl group which may have a substituent. n represents an integer of 1 to 3.

In the general formula 8, X _{5 to} X ₈ each independently represent N or C—R ₅₀₁ , and R ₅₀₁ represents a hydrogen atom or a substituent. At least one of X _5, X ₆ is C-R _501, at least one of R ₅₀₁ represents a substituent. And at least one of X ₇ and X ₈ is C—R ₅₀₁ , and at least one of R ₅₀₁ represents a substituent. Such a triarylamine compound improves the stability and the durability of the device.

  Next, a compound represented by the general formula 9 is exemplified.

In Formula 9, R _{833 to} R ₈₇₄ each independently represent a hydrogen atom or a substituent. However, one of R _833, R ₈₃₄ represents a substituent, any one of R _835, R ₈₃₆ represents a substituent, any one of R _837, R ₈₃₈ represents a substituent, R _839, Any of R ₈₄₀ represents a substituent, any of R ₈₄₁ and R ₈₄₂ represents a substituent, and any of R ₈₄₃ and R ₈₄₄ represents a substituent.

  In the phenylenediamine skeleton, by introducing a substituent having steric hindrance into the phenylene portion of the phenylenediamine, the 0-0 band of the phosphorescent spectrum can be shortened (excitation triplet energy is increased). Although it has been described that it is preferable to introduce a substituent at a position other than the 2,6-position in triphenylamine, the instability of the compound is also reduced in the phenylenediamine skeleton.

  In addition, among the triarylamine compounds, a triarylamine compound having a terminal group represented by the aforementioned general formula 10-1, 10-2, 10-3, or 10-4 is exemplified.

In the general formulas 10-1, 10-2, 10-3, and 10-4, X ₉ and X ₁₀ each independently represent N, O, S, or C—R ₆₁₁ , and R ₆₁₁ is hydrogen. Represents an atom or a substituent, and at least one of X ₉ and X ₁₀ is C—R ₆₁₁ , wherein R ₆₁₁ is a substituent. Z ₆₀₁ represents an atom group necessary for forming an aromatic carbocyclic ring or an aromatic heterocyclic ring together with X ₉ and X ₁₀ . R _{601 to} R ₆₀₅ each independently represent a hydrogen atom or a substituent, and at least one of R ₆₀₁ and R ₆₀₅ is a substituent. R _{606 to} R ₆₁₀ each independently represent a substituent.

  Ortho and para orientations of the terminal groups of the compound are particularly likely to be degraded in triphenylamine derivatives and phenylenediamine derivatives. By introducing a substituent at this position, the stability of the compound can be effectively improved. In particular, the present invention is characterized by a hole transport compound having a large excited triplet energy, and such a compound naturally has a wide band gap and cannot be said to have good stability of the compound. Therefore, introduction of such a group is very effective in terms of the durability of the device. It seems that unsubstituted triphenylamine may be used, but in practice, good results cannot be obtained because of crystallization.

  Next, compounds represented by the following general formulas 16-1 and 16-2 are exemplified.

In Formulas 16-1 and 16-2, R _{875 to} R ₉₅₃ represent a hydrogen atom or a substituent. Here, at least one of R _{875 to} R ₈₇₈ represents a substituent, at least one of R _{879 to} R ₈₈₂ represents a substituent, and at least one of R _{883 to} R ₈₈₆ represents a substituent. R _{910 to} R ₉₅₃ represent a hydrogen atom or a substituent. Provided that at least one of R _{910 to} R ₉₁₃ represents a substituent, at least one of R _{914 to} R ₉₁₇ represents a substituent, and at least one of R _{918 to} R ₉₂₁ represents a substituent; At least one of R _{922 to} R ₉₂₅ represents a substituent, and at least one of R _{926 to} R ₉₂₉ represents a substituent.

  Examples of the triarylamine compound are shown below, but the invention is not limited thereto.

The triarylamine compound preferably has a 0-0 band in the phosphorescence spectrum of from 300 nm to 450 nm, more preferably from 350 to 430 nm. Thereby, the luminous efficiency can be further increased. Further, the molecular weight of the triarylamine compound is preferably 550 to 2,000. When the molecular weight is 550 to 2,000, Tg (glass transition temperature) increases, the thermal stability improves, and the device life is improved. More preferred molecular weight is 800-2000.

  In the present invention, as described above, the hole transporting material is preferably a triarylamine compound. In addition, a compound having a phenylenediamine skeleton may also be introduced with a sterically hindered group to obtain a phosphorescent spectrum. 0-0 band can satisfy 300 nm to 450 nm. The material is not limited to these as long as it is a hole transporting material in which the 0-0 band of the phosphorescent spectrum satisfies 300 nm to 450 nm.

<< Constituent Layer of Organic EL Element >>
The constituent layers of the organic EL device of the present invention will be described.

In the present invention, preferred specific examples of the layer constitution of the organic EL element are shown below, but the present invention is not limited to these.
(I) anode / light emitting layer / electron transport layer / cathode (ii) anode / hole transport layer / light emitting layer / electron transport layer / cathode (iii) anode / hole transport layer / light emitting layer / hole blocking layer / electron Transport layer / cathode (iv) anode / hole transport layer / emission layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode (v) anode / anode buffer layer / hole transport layer / emission layer / hole Blocking layer / Electron transport layer / Cathode buffer layer / Cathode << Anode >>
As the anode in the organic EL element, a metal, an alloy, an electrically conductive compound, or a mixture thereof having a large work function (4 eV or more) as an electrode material is preferably used. Specific examples of such an electrode material include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ , and ZnO. Alternatively, a material such as IDIXO (In ₂ O ₃ —ZnO) that can form an amorphous and transparent conductive film may be used. The anode may form a thin film by depositing these electrode materials by a method such as evaporation or sputtering, and form a pattern of a desired shape by a photolithography method, or when the pattern accuracy is not so required (100 μm or more). Degree), a pattern may be formed through a mask having a desired shape at the time of vapor deposition or sputtering of the electrode material. When light is extracted from the anode, the transmittance is desirably greater than 10%, and the sheet resistance of the anode is preferably several hundred Ω / □ or less. Further, the thickness depends on the material, but is usually selected in the range of 10 to 1000 nm, preferably 10 to 200 nm.

"cathode"
On the other hand, as a cathode, a metal having a small work function (4 eV or less) (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof are used as an electrode material. Specific examples of such an electrode material include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O) ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among them, from the viewpoint of electron injecting property and durability against oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a large work function, such as a magnesium / silver mixture, magnesium / Aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) mixture, lithium / aluminum mixture, aluminum and the like are preferred. The cathode can be manufactured by forming a thin film from these electrode substances by a method such as vapor deposition or sputtering. Further, the sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 to 200 nm. In order to transmit emitted light, it is convenient if one of the anode and the cathode of the organic EL element is transparent or translucent, because the emission luminance is improved.

  Further, after the metal is formed in the cathode in a thickness of 1 to 20 nm, a transparent or translucent cathode can be manufactured by manufacturing the conductive transparent material described in the description of the anode thereon. By applying this, an element in which both the anode and the cathode have transparency can be manufactured.

  Next, an injection layer, a blocking layer, an electron transport layer, and the like used as constituent layers of the organic EL device of the present invention will be described.

<< Injection Layer >>: Electron Injection Layer, Hole Injection Layer The injection layer is provided as necessary, and there are an electron injection layer and a hole injection layer, as described above, between the anode and the light emitting layer or the hole transport layer, and It may be present between the cathode and the light emitting layer or the electron transport layer.

  The injection layer is a layer provided between an electrode and an organic layer for lowering a driving voltage and improving light emission luminance. “The organic EL element and the forefront of its industrialization (published by NTT Corporation on November 30, 1998) )), Vol. 2, Chapter 2, “Electrode Materials” (pages 123 to 166), which includes a hole injection layer (anode buffer layer) and an electron injection layer (cathode buffer layer).

  The details of the anode buffer layer (hole injection layer) are also described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069 and the like, and specific examples thereof include copper phthalocyanine. Examples include a phthalocyanine buffer layer, an oxide buffer layer represented by vanadium oxide, an amorphous carbon buffer layer, and a polymer buffer layer using a conductive polymer such as polyaniline (emeraldine) or polythiophene.

  The details of the cathode buffer layer (electron injection layer) are also described in JP-A-6-325871, JP-A-9-17574, and JP-A-10-74586, and specifically, typified by strontium and aluminum. Metal buffer layer, an alkali metal compound buffer layer represented by lithium fluoride, an alkaline earth metal compound buffer layer represented by magnesium fluoride, an oxide buffer layer represented by aluminum oxide, and the like. The buffer layer (injection layer) is desirably an extremely thin film, and its thickness is preferably in the range of 0.1 nm to 5 μm, depending on the material.

<< blocking layer >>: hole blocking layer, electron blocking layer As described above, the blocking layer is provided as necessary in addition to the basic constituent layers of the organic compound thin film. For example, Japanese Patent Application Laid-Open Nos. 11-204258 and 11-204359, and pages 237 of "Organic EL Devices and Their Forefront of Industrialization (published by NTT Corporation on November 30, 1998)" and the like. There is a hole blocking (hole block) layer.

  The hole blocking layer is an electron transporting layer in a broad sense, and is made of a material having a function of transporting electrons and having an extremely small ability to transport holes. And the recombination probability of holes can be improved.

  On the other hand, an electron blocking layer is a hole transporting layer in a broad sense, and is made of a material that has a function of transporting holes and has a very small ability to transport electrons, and it blocks electrons while transporting holes. Thus, the recombination probability of electrons and holes can be improved.

<< Light-emitting layer >>
The light-emitting layer according to the present invention is an electrode or an electron-transport layer, a layer that emits light by recombination of electrons and holes injected from the hole-transport layer, and a light-emitting portion is in the light-emitting layer. May be the interface between the light emitting layer and the adjacent layer.

  The material used for the light-emitting layer (hereinafter, referred to as a light-emitting material) is a phosphorescent compound. In the present invention, the phosphorescent compound is a compound in which light emission from an excited triplet is observed, and is performed at room temperature (25 ° C.). ) Is a compound that emits phosphorescence, and has a phosphorescence quantum yield of 0.01 or more at 25 ° C. The phosphorescence quantum yield is preferably 0.1 or more.

  The phosphorescence quantum yield can be measured by the method described in Spectroscopy II, 4th Edition, pp. 398 (1992 edition, Maruzen) of Experimental Chemistry Course 7. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescent compound used in the present invention only needs to achieve the above-mentioned phosphorescence quantum yield in any of the solvents.

  Emission of a phosphorescent compound can be categorized into two types in principle. One is the recombination of carriers on the host compound where the carriers are transported, and the excited state of the host compound is generated. An energy transfer type in which light is emitted from a phosphorescent compound by transferring it to a compound.The other is that the phosphorescent compound becomes a carrier trap, and recombination of carriers occurs on the phosphorescent compound, causing the phosphorescent compound to emit light. Is obtained, in which case the energy of the excited state of the phosphorescent compound is lower than the energy of the excited state of the host compound.

  The phosphorescent compound can be appropriately selected from known compounds used for the light emitting layer of the organic EL device.

  The phosphorescent compound used in the present invention is preferably a complex compound containing a metal belonging to Group 8 of the periodic table of elements, and more preferably an iridium compound, an osmium compound, or a platinum compound (platinum complex-based compound). Compound) and a rare earth complex, and among them, the most preferable is an iridium compound.

  Hereinafter, specific examples of the phosphorescent compound used in the present invention are shown, but the invention is not limited thereto. These compounds are described, for example, in Inorg. Chem. 40, 1704-1711.

  In the present invention, the maximum phosphorescent emission wavelength of the phosphorescent compound is not particularly limited, and in principle, it can be obtained by selecting a central metal, a ligand, a substituent of a ligand, and the like. Although the emission wavelength of the phosphorescent compound can be changed, the phosphorescence emission wavelength of the phosphorescent compound preferably has a maximum wavelength of phosphorescence at 380 to 480 nm. With such an organic EL element emitting blue phosphorescent light or an organic EL element emitting white phosphorescent light, the luminous efficiency can be further improved.

  Further, the light emitting layer may contain a host compound in addition to the phosphorescent compound.

  In the present invention, the host compound is a compound having a phosphorescence quantum yield of phosphorescence at room temperature (25 ° C.) of less than 0.01 among the compounds contained in the light emitting layer.

  The host compound is preferably an organic compound or a complex. In the present invention, the host compound preferably has an excited triplet energy larger than that of the phosphorescent compound.

  In the present invention, the 0-0 band of the phosphorescence spectrum of the host compound is preferably in the range of 300 nm to 450 nm, whereby the luminous efficiency can be further enhanced, and in particular, BGR light emission is possible.

  That is, by making the excited triplet energy of the host compound larger than the excited triplet energy of the phosphorescent compound, phosphorescence emission of energy transfer type from the host compound to the phosphorescent compound can be performed. Further, a compound in which the wavelength of the 0-0 band in the phosphorescence spectrum of the host compound is 450 nm or less has a very wide band gap (ionization potential-electron affinity, HOMO-LUMO), and thus works advantageously for a carrier trap type.

  As such a host compound, any one of known compounds used in an organic EL device can be selected and used, and most of the hole transporting material and the electron transporting material described below are used as the host of the light emitting layer. It can also be used as a compound.

  A polymer material such as polyvinyl carbazole or polyfluorene may be used, and a polymer material in which the host compound is introduced into a polymer chain or in which the host compound is a polymer main chain may be used.

  Further, a plurality of host compounds and phosphorescent compounds may be used. By using a plurality of types of host compounds, it is possible to adjust the transfer of electric charges, and to increase the efficiency of the organic EL device. In addition, by using a plurality of kinds of phosphorescent compounds, different luminescence can be mixed, and thus, an arbitrary luminescent color can be obtained. By adjusting the type and the doping amount of the phosphorescent compound, white light emission is possible, and application to illumination and backlight is also possible.

  As the host compound, a compound which has a hole-transporting ability and an electron-transporting ability, prevents a long wavelength emission, and has a high Tg (glass transition temperature) is preferable.

  As the host compound, a carbazole derivative is preferable, and a compound having the performance of a single carbazole ring, more preferably a single N-phenylcarbazole or a single N-alkylcarbazole is effective. A carbazole ring alone, an N-phenylcarbazole alone, or an N-alkylcarbazole alone has a low glass transition point, which is unfavorable in terms of device life, and is increased in molecular weight to ensure thermal stability. At this time, sufficient consideration is required for the linking group so that the performance of the carbazole ring alone, N-phenylcarbazole alone, or N-alkylcarbazole alone can be maintained.

  When linked by a simple phenyl group or naphthalene group as used in organic EL materials, the conjugation is extended and the excited triplet energy is reduced. Therefore, the performance can be maintained by twisting the dihedral angle of the aromatic ring to 50 degrees or more by the substituent or using an alkyl group for the connection.

  In the present invention, a carbazole derivative represented by the following general formula is preferred.

  First, a compound represented by the general formula 11 can be mentioned.

In Formula 11, R _{1001 to} R ₁₀₁₃ each independently represent a hydrogen atom or a substituent, and at least one of them represents a substituent.

When R _{1001 to} R ₁₀₁₃ are an aryl group or a heteroaryl group, the dihedral angle connecting the aryl group, the heteroaryl group, and the phenylcarbazole is preferably 50 degrees or more. This can be sterically controlled by introducing a substituent.

  Note that, as described in the hole transporting material used in the present invention, a group having only a substituent, an aryl group, or a heteroaryl group and having a phosphorescence 0-0 band of 450 nm or more is not appropriate.

When three-dimensional control is not performed without introducing a substituent, the dihedral angle is generally 50 degrees or less. In such a state, the triplet energy of excitation may be reduced due to the extension of the conjugate length (the 0-0 band of phosphorescence becomes longer in wavelength).
Next, a compound represented by the general formula 12 is exemplified.

In the general formula 12, R ₁₀₂₁ represents an alkyl group, a cycloalkyl group, or a fluorinated alkyl group, and R _{1022 to} R ₁₀₂₉ each independently represent a hydrogen atom or a substituent. Represents a substituent.

When R _{1022 to} R ₁₀₂₉ are an aryl group or a heteroaryl group, the dihedral angle connecting the aryl group, the heteroaryl group, and the phenylcarbazole is preferably 50 degrees or more.

  Next, a compound represented by the general formula 13 is exemplified.

Wherein in Formula 13, R ₁₀₃₁ to R ₁₀₄₆ each independently represent a hydrogen atom or a substituent,, L ₃ is a divalent linking group, or represents a direct bond, in the case of a direct bond R _1037, Any of R ₁₀₃₈ , R ₁₀₄₅ and R ₁₀₄₆ represents a substituent.

  Next, a compound represented by the general formula 14 is exemplified.

In Formula 14, R _{1051 to} R ₁₀₆₃ each independently represent a hydrogen atom or a substituent, and any of R ₁₀₅₇ , R ₁₀₅₈ , R ₁₀₆₂ , and R ₁₀₆₃ represents a substituent.

  Next, a compound represented by the general formula 15 is exemplified.

In Formula 15, R _{1071 to} R ₁₀₇₉ each independently represent a hydrogen atom or a substituent, and either R ₁₀₇₂ or R ₁₀₇₃ represents a substituent. n represents an integer of 1 to 8.

  Examples of the carbazole derivative are shown below, but the invention is not limited thereto.

  In the present invention, by combining the hole transport material of the present invention and the above-described host compound, a great effect can be obtained particularly in luminous efficiency.

  In addition, the light emitting layer may further contain a host compound having a maximum fluorescence wavelength as the host compound. In this case, by the energy transfer from the other host compound and the phosphorescent compound to the fluorescent compound, the electroluminescence as the organic EL device can also obtain the light emission from the other host compound having the maximum fluorescence wavelength. Preferred as the host compound having the fluorescence maximum wavelength is one having a high fluorescence quantum yield in a solution state. Here, the fluorescence quantum yield is preferably 10% or more, particularly preferably 30% or more. Specific examples of host compounds having a fluorescence maximum wavelength include coumarin-based dyes, pyran-based dyes, cyanine-based dyes, croconium-based dyes, squarium-based dyes, oxobenzanthracene-based dyes, fluorescein-based dyes, rhodamine-based dyes, and pyrylium-based dyes And perylene dyes, stilbene dyes, and polythiophene dyes. The fluorescence quantum yield can be measured by the method described in Spectroscopy II, p. 362 (1992 edition, Maruzen) of the 4th edition of Experimental Chemistry Course 7.

  The color of light emitted in this specification is measured by a spectral radiance meter CS-1000 (manufactured by Minolta) in FIG. 4.16 on page 108 of “New Color Science Handbook” (edited by The Japan Society of Color Science, University of Tokyo Press, 1985). It is determined by the color when the measured result is applied to the CIE chromaticity coordinates.

  The light-emitting layer can be formed by forming the above compound by a known thinning method such as a vacuum evaporation method, a spin coating method, a casting method, an LB method, and an ink-jet method. The thickness of the light emitting layer is not particularly limited, but is usually selected in the range of 5 nm to 5 μm, preferably 5 to 200 nm. The light-emitting layer may have a single-layer structure composed of one or more of these phosphorescent compounds or host compounds, or a laminated structure composed of a plurality of layers having the same composition or different compositions. Good.

《Hole transport layer》
The hole transport layer is made of a hole transport material having a function of transporting holes. In a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer. The hole transport layer can be provided as a single layer or a plurality of layers.

  In the present invention, one or more of the above-described hole transport materials can be used as the hole transport material adjacent to the light emitting layer.

  In the organic EL device of the present invention, it is preferable that the ionization potential of the hole transporting material in the hole transporting layer adjacent to the light emitting layer is 5.00 to 5.70 eV. More preferably, it is 5.00 to 5.45 eV. Thereby, the luminous efficiency can be further increased and the driving voltage can be reduced.

  In the present invention, the ionization potential is defined as the energy required to emit an electron at the HOMO (highest occupied molecular orbital) level of a compound to a vacuum level. Energy required to extract electrons from the compound, which can be measured directly by photoelectron spectroscopy. In the present invention, a value measured by ESCA 5600 UPS (ultraviolet photoemission spectroscopy) manufactured by ULVAC-PHI, INC. Is used.

  In the present invention, it is preferable that the ionization potential Ip1 (eV) of the hole transport material of the hole transport layer adjacent to the light emitting layer and the ionization potential Ip3 (eV) of the phosphorescent compound of the light emitting layer satisfy the following expression, Thereby, energy efficiency can be improved, and luminous efficiency can be further improved.

−0.1 eV ≦ Ip3-Ip1 ≦ 0.5 eV
In the present invention, the ionization potential Ip1 (eV) of the hole transport material of the hole transport layer adjacent to the light emitting layer and the ionization potential Ip2 (eV) of the host compound of the light emitting layer preferably satisfy the following formula. In addition, energy efficiency can be improved, and luminous efficiency can be further improved.

0.3 eV <Ip2-Ip1 <1.0 eV
In the present invention, the electron affinity Ea1 (eV) of the hole transport material of the hole transport layer adjacent to the light emitting layer and the excited triplet level T3 (eV) of the phosphorescent compound of the light emitting layer satisfy the following expression. Is preferred.

0.5 eV <T3-Ea1 <1.3 eV
T3 (eV) can be determined by subtracting the excited triplet energy from Ip3 (eV) of the phosphorescent compound.

  The phosphorescent compound in the excited triplet state is more active than the ground state and is easily oxidized. Therefore, the phosphorescent compound may be deactivated by the transfer of electrons to and from a hole transporting material existing around the phosphorescent compound. However, the electron affinity Ea1 (eV) of the hole transporting material and the excited triplet of the phosphorescent compound may be reduced. When the level T3 (eV) satisfies the above relationship, the transfer of electrons is restricted to prevent deactivation, whereby the luminous efficiency can be further improved.

In the present invention, the electron affinity is defined as the energy at which electrons at a vacuum level fall to the LUMO (lowest unoccupied molecular orbital) level of a substance and are stabilized,
Electron affinity (eV) = ionization potential Ip (eV) + band gap (eV)
Can be obtained by

  In the present invention, the band gap represents the energy between HOMO and LUMO of a molecule. Specifically, a film is formed on a quartz substrate, an absorption spectrum is measured, and the band gap is determined from the absorption edge.

  In the present invention, the electron affinity Ea1 (eV) of the hole transport material of the hole transport layer adjacent to the light emitting layer and the electron affinity Ea2 (eV) of the host compound of the light emitting layer are 0.1 eV <Ea2−Ea1 <0. It preferably satisfies 8 eV, and most preferably satisfies 0.3 eV <Ea2−Ea1 <0.5 eV. By satisfying the above relationship between the electron affinity Ea1 (eV) of the hole transport material and the electron affinity Ea2 (eV) of the host compound, the transfer of electrons from the hole transport material to the host compound is restricted. Recombination of holes and electrons can be increased, and luminous efficiency can be further increased.

  According to the present invention, a hole transport layer is further provided adjacent to the hole transport layer and opposite to the light emitting layer, and the ion transport potential Ip4 (eV) of the hole transport layer and the hole transport material adjacent to the light emitting layer It is preferable that the ionization potential Ip1 (eV) satisfies 0.1 eV <Ip1−Ip4 <0.7 eV. By further providing a hole transport layer that satisfies the above relationship, it has been improved that injection of holes into the hole transport layer was not performed smoothly due to a difference in energy gap between the anode and the hole transport layer. Hole injection can be performed efficiently, whereby the luminous efficiency can be further increased and the driving voltage can be reduced. Further, at this time, it is preferable that the thickness of the hole transport layer adjacent to the light emitting layer is 5 to 20 nm, whereby holes are more effectively injected into the hole transport layer, and the luminous efficiency is further improved. Can be increased. In particular, the driving voltage can be reduced.

  The hole transporting material contained in the hole transporting layer adjacent to the hole transporting layer and located on the opposite side to the light emitting layer has a property of injecting or transporting holes or having a barrier property against electrons. Yes, it may be either organic or inorganic. For example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styryl anthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbenes Derivatives, silazane derivatives, aniline-based copolymers, conductive polymer oligomers, especially thiophene oligomers, and the like can be given.

  As the hole transporting material contained in the hole transporting layer adjacent to the hole transporting layer and on the opposite side to the light emitting layer, the above-mentioned materials can be used. It is preferable to use a tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound.

  Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N, N ', N'-tetraphenyl-4,4'-diaminophenyl; N, N'-diphenyl-N, N'- Bis (3-methylphenyl)-[1,1'-biphenyl] -4,4'-diamine (TPD); 2,2-bis (4-di-p-tolylaminophenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ', N'-tetra-p-tolyl-4,4'-diaminobiphenyl; 1,1-bis (4-di-p-tolyl Aminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-p-tolylaminophenyl) phenylmethane; N, N'-diphenyl-N, N ' − (4-methoxyphenyl) -4,4'-diaminobiphenyl; N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) quadriphenyl; N, N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenylamino- (2-diphenylvinyl) benzene; 3-methoxy-4'-N, N-diphenylaminostilbene; N-phenylcarbazole, and also two of the two described in U.S. Pat. No. 5,061,569. Those having a condensed aromatic ring in the molecule, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-30868 No. 4,4 ', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (MTDATA) in which three triphenylamine units described in the above-mentioned publication are linked in a starburst type. And the like.

  Further, a polymer material in which these materials are introduced into a polymer chain, or a polymer material in which these materials are used as a polymer main chain can be used. Further, inorganic compounds such as p-type Si and p-type SiC can also be used as the hole injection material and the hole transport material.

  The hole transport layer can be formed by thinning the hole transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an inkjet method, and an LB method. it can. The thickness of the hole transport layer is not particularly limited, but is usually about 5 nm to 5 μm, preferably 5 to 200 nm. The hole transport layer may have a single-layer structure made of one or more of the above materials.

《Electron transport layer》
The electron transport layer is made of a material having a function of transporting electrons. In a broad sense, the electron transport layer includes an electron injection layer and a hole blocking layer. The electron transport layer can be provided as a single layer or a plurality of layers.

  Conventionally, the following materials are used as an electron transporting material (also serving as a hole blocking material) used for a single layer of an electron transporting layer and an electron transporting layer adjacent to the light emitting layer on the cathode side with respect to the light emitting layer. Are known.

  Further, the electron transporting layer only needs to have a function of transmitting electrons injected from the cathode to the light emitting layer, and as the material thereof, any one of conventionally known compounds can be selected and used. .

  Examples of materials used for the electron transport layer (hereinafter, referred to as electron transport materials) include nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethanes, and anthrones. Derivatives, oxadiazole derivatives and the like. Further, in the oxadiazole derivative, a thiadiazole derivative in which an oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as the electron transport material.

  Further, a polymer material in which these materials are introduced into a polymer chain, or a polymer material in which these materials are used as a polymer main chain, can also be used.

  Further, a metal complex of an 8-quinolinol derivative, such as tris (8-quinolinol) aluminum (Alq), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) aluminum, Tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), and the like, and the central metals of these metal complexes are In, Mg, Cu , Ca, Sn, Ga or Pb can also be used as the electron transport material. In addition, metal-free or metal phthalocyanine, or those whose terminals are substituted with an alkyl group, a sulfonic acid group, or the like can be preferably used as the electron transporting material. Further, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can be used as the electron transporting material, and similarly to the hole injection layer and the hole transport layer, inorganic materials such as n-type Si and n-type SiC can be used. Semiconductors can also be used as electron transport materials.

  The electron transport layer can be formed by thinning the electron transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an inkjet method, and an LB method. The thickness of the electron transport layer is not particularly limited, but is usually about 5 nm to 5 μm, preferably 5 to 200 nm. The electron transport layer may have a single-layer structure made of one or more of the above materials.

<< Substrate (also referred to as substrate, substrate, support, etc.) >>
The organic EL device of the present invention is preferably formed on a substrate.

  The substrate of the organic EL device of the present invention is not particularly limited in the type of glass, plastic, and the like, and is not particularly limited as long as it is transparent. A light-transmitting resin film can be used. A particularly preferred substrate is a resin film that can provide flexibility to the organic EL element.

  Examples of the resin film include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyether sulfone (PES), polyether imide, polyether ether ketone, polyphenylene sulfide, polyarylate, polyimide, polycarbonate (PC), and cellulose triacetate. (TAC), cellulose acetate propionate (CAP) and the like. An inorganic or organic coating or a hybrid coating of both may be formed on the surface of the resin film.

  The external extraction efficiency at room temperature of light emission of the organic electroluminescence device of the present invention is preferably 1% or more, more preferably 5% or more. Here, the external extraction quantum efficiency (%) = the number of photons emitted to the outside of the organic EL element / the number of electrons flowing to the organic EL element × 100.

  Further, a hue improvement filter such as a color filter may be used in combination, or a color conversion filter for converting the emission color of the organic EL element into multiple colors using a phosphor may be used in combination. When a color conversion filter is used, λmax of light emission of the organic EL element is preferably 480 nm or less.

<< Method of manufacturing organic EL element >>
As an example of a method for producing an organic EL device of the present invention, a method for producing an organic EL device comprising an anode / a hole injection layer / a hole transport layer / a light emitting layer / an electron transport layer / an electron injection layer / a cathode will be described.

  First, a thin film made of a desired electrode material, for example, a material for an anode is formed on an appropriate substrate by a method such as vapor deposition or sputtering so as to have a thickness of 1 μm or less, preferably 10 to 200 nm, thereby producing an anode. I do. Next, organic compound thin films of a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and a hole blocking layer, which are organic EL element materials, are formed thereon.

As a method for thinning the organic compound thin film, there are a vapor deposition method and a wet process (spin coating method, casting method, ink jet method, printing method) as described above, but a uniform film is easily obtained and a pinhole is formed. In particular, a vacuum evaporation method, a spin coating method, an ink jet method, and a printing method are particularly preferable from the viewpoint that hardly occurs. Further, a different film forming method may be applied to each layer. When a vapor deposition method is used for film formation, the vapor deposition conditions vary depending on the type of compound used, etc., but generally, the boat heating temperature is 50 to 450 ° C., the degree of vacuum is 10 ⁻⁶ to 10 ⁻² Pa, and the vapor deposition rate is 0.01. To 50 nm / sec, a substrate temperature of -50 to 300 ° C., a film thickness of 0.1 nm to 5 μm, preferably 5 to 200 nm.

  After forming these layers, a thin film made of a material for a cathode is formed thereon by a method such as vapor deposition or sputtering so as to have a thickness of 1 μm or less, preferably in a range of 50 to 200 nm, and a cathode is provided. As a result, a desired organic EL device is obtained. In the production of this organic EL element, it is preferable to produce from the hole injection layer to the cathode consistently by one evacuation, but it is also possible to take it out in the middle and apply a different film forming method. At that time, it is necessary to consider that the operation is performed in a dry inert gas atmosphere.

  The multi-color display device of the present invention is provided with a shadow mask only when the light emitting layer is formed, and since the other layers are common, patterning such as a shadow mask is unnecessary. The film can be formed by a method, a printing method, or the like.

  When patterning is performed only on the light emitting layer, the method is not particularly limited, but is preferably an evaporation method, an inkjet method, or a printing method. When using an evaporation method, patterning using a shadow mask is preferable.

  In addition, it is also possible to reverse the manufacturing order and manufacture the cathode, the electron injection layer, the electron transport layer, the light emitting layer, the hole transport layer, the hole injection layer, and the anode in this order. When a DC voltage is applied to the thus obtained multicolor display device, light emission can be observed by applying a voltage of about 2 to 40 V with the positive polarity of the anode and the negative polarity of the cathode. Alternatively, an AC voltage may be applied. The waveform of the applied AC may be arbitrary.

  The multicolor display device of the present invention can be used as a display device, a display, and various light emission light sources. In a display device and a display, full-color display can be performed by using three types of organic EL elements emitting blue, red, and green light.

  Examples of the display device and display include a television, a personal computer, a mobile device, an AV device, a teletext display, and information display in a car. In particular, it may be used as a display device for reproducing a still image or a moving image, and when used as a display device for reproducing a moving image, the driving method may be either a simple matrix (passive matrix) method or an active matrix method.

  Lighting sources include home lighting, interior lighting, backlights for watches and LCDs, signboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copiers, light sources for optical communication processors, and light sources for optical sensors. But not limited thereto.

  Further, the organic EL device according to the present invention may be used as an organic EL device having a resonator structure.

  The intended use of the organic EL device having such a resonator structure is, for example, a light source of an optical storage medium, a light source of an electrophotographic copying machine, a light source of an optical communication processor, a light source of an optical sensor, and the like. Not limited. In addition, laser oscillation may be used for the above purpose.

《Display device》
The organic EL element of the present invention may be used as a kind of lamp such as an illumination light source or an exposure light source, a projection device for projecting an image, or a display for directly viewing a still image or a moving image. It may be used as a device (display). When used as a display device for reproducing moving images, the driving method may be either a simple matrix (passive matrix) method or an active matrix method. Alternatively, a full-color display device can be manufactured by using three or more kinds of the organic EL elements of the present invention having different emission colors. Alternatively, it is also possible to convert one luminescent color, for example, white luminescence, to BGR using a color filter to achieve full color. Further, it is possible to convert the luminescent color of the organic EL to another color by using a color conversion filter to obtain a full color. In this case, the λmax of the organic EL luminescence is preferably 480 nm or less.

  An example of a display device including the organic EL element of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic diagram illustrating an example of a display device including an organic EL element. FIG. 3 is a schematic diagram of a display such as a mobile phone for displaying image information by light emission of an organic EL element.

  The display 1 includes a display unit A having a plurality of pixels, a control unit B that performs image scanning of the display unit A based on image information, and the like.

  The control unit B is electrically connected to the display unit A, sends a scanning signal and an image data signal to each of the plurality of pixels based on image information from the outside, and the pixels for each scanning line are converted into an image data signal by the scanning signal. In response, the light is sequentially emitted, the image is scanned, and the image information is displayed on the display unit A.

  FIG. 2 is a schematic diagram of the display unit A.

  The display section A has a wiring section including a plurality of scanning lines 5 and data lines 6 and a plurality of pixels 3 on a substrate. The main members of the display unit A will be described below. FIG. 2 shows a case where the light emitted from the pixel 3 is extracted in the white arrow direction (downward).

  The scanning lines 5 and the plurality of data lines 6 of the wiring portion are each made of a conductive material, and the scanning lines 5 and the data lines 6 are orthogonal to each other in a grid pattern and are connected to the pixels 3 at orthogonal positions (for details, FIG. Not shown).

  When a scanning signal is applied from the scanning line 5, the pixel 3 receives an image data signal from the data line 6 and emits light according to the received image data. By appropriately arranging pixels in a red region, pixels in a green region, and pixels in a blue region on the same substrate, full-color display becomes possible.

  Next, a light emitting process of the pixel will be described.

  FIG. 3 is a schematic diagram of a pixel.

  Each pixel includes an organic EL element 10, a switching transistor 11, a driving transistor 12, a capacitor 13, and the like. A full-color display can be performed by using red, green, and blue light-emitting organic EL elements as the organic EL elements 10 in a plurality of pixels and juxtaposing them on the same substrate.

  In FIG. 3, an image data signal is applied from the control unit B to the drain of the switching transistor 11 via the data line 6. When a scanning signal is applied to the gate of the switching transistor 11 from the control unit B via the scanning line 5, the driving of the switching transistor 11 is turned on, and the image data signal applied to the drain is transferred to the capacitor 13 and the driving transistor 12. Transmitted to the gate.

  By transmitting the image data signal, the capacitor 13 is charged according to the potential of the image data signal, and the driving of the drive transistor 12 is turned on. The driving transistor 12 has a drain connected to the power supply line 7, a source connected to the electrode of the organic EL element 10, and from the power supply line 7 to the organic EL element 10 according to the potential of the image data signal applied to the gate. Current is supplied.

  When the scanning signal is transferred to the next scanning line 5 by the sequential scanning of the control unit B, the driving of the switching transistor 11 is turned off. However, even when the driving of the switching transistor 11 is turned off, the capacitor 13 holds the potential of the charged image data signal, so that the driving of the driving transistor 12 is kept on and the next scanning signal is applied. The light emission of the organic EL element 10 continues until this. When the next scanning signal is applied by the sequential scanning, the driving transistor 12 is driven according to the potential of the next image data signal synchronized with the scanning signal, and the organic EL element 10 emits light.

  That is, the organic EL element 10 emits light by providing a switching transistor 11 and a driving transistor 12 as active elements to the organic EL elements 10 of each of the plurality of pixels, and emitting light of the organic EL elements 10 of each of the plurality of pixels 3. It is carried out. Such a light emitting method is called an active matrix method.

  Here, the light emission of the organic EL element 10 may be light emission of a plurality of gradations based on a multi-valued image data signal having a plurality of gradation potentials, or ON / OFF of a predetermined light emission amount based on a binary image data signal. May be.

  Further, the holding of the potential of the capacitor 13 may be continued until the next scanning signal is applied, or may be discharged immediately before the next scanning signal is applied.

  The present invention is not limited to the active matrix method described above, but may be a passive matrix light emission drive in which the organic EL element emits light in accordance with a data signal only when a scanning signal is scanned.

  FIG. 4 is a schematic view of a display device using a passive matrix system. In FIG. 4, a plurality of scanning lines 5 and a plurality of image data lines 6 are provided in a lattice shape facing each other with the pixel 3 interposed therebetween.

  When the scanning signal of the scanning line 5 is applied by the sequential scanning, the pixels 3 connected to the applied scanning line 5 emit light according to the image data signal. In the passive matrix system, the pixel 3 has no active element, and the manufacturing cost can be reduced.

  Hereinafter, the present invention will be described with reference to examples, but embodiments of the present invention are not limited thereto.

Example 1
<Preparation of organic EL elements 1-1 to 1-19>
A 100 mm × 100 mm × 1.1 mm glass substrate as an anode is patterned on a substrate (NA45, manufactured by NH Techno Glass Co., Ltd.) on which 100 nm of ITO (indium tin oxide) is formed, and then a transparent support provided with this ITO transparent electrode is provided. The substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and washed with UV ozone for 5 minutes. This transparent support substrate was fixed to a substrate holder of a commercially available vacuum evaporation apparatus, while 200 mg of α-NPD was placed in a molybdenum resistance heating boat, 200 mg of CBP was placed in another molybdenum resistance heating boat, and another molybdenum resistance heating boat was placed. 200 mg of bathocuproin (BCP) was placed in a heating boat, 100 mg of Ir-1 was placed in another molybdenum resistance heating boat, and 200 mg of Alq ₃ was further placed in another molybdenum resistance heating boat, and attached to a vacuum evaporation apparatus.

Next, after the pressure in the vacuum chamber was reduced to 4 × 10 ⁻⁴ Pa, the heating boat containing α-NPD was energized and heated, and was vapor-deposited on the transparent support substrate at a vapor deposition rate of 0.1 nm / sec. A transport layer was provided. Further, the heating boat containing CBP and Ir-1 was energized and heated, and co-deposited on the hole transport layer at a deposition rate of 0.2 nm / sec and 0.012 nm / sec to form a light emitting layer. Was. In addition, the substrate temperature at the time of vapor deposition was room temperature. Further, an electric current is applied to the heating boat containing the BCP, and the heating boat is heated to be deposited on the light emitting layer at a deposition rate of 0.1 nm / sec to provide a 10 nm-thick electron transport layer also serving as a hole blocking layer. Was. On top of that, the heating boat containing Alq ₃ was further energized and heated, and was vapor-deposited on the electron transport layer at a vapor deposition rate of 0.1 nm / sec to further provide an electron injection layer having a thickness of 40 nm. . In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Subsequently, 0.5 nm of lithium fluoride and 110 nm of aluminum were vapor-deposited to form a cathode, thereby producing an organic EL device 1-1. Other organic EL devices shown in Table 1 were produced in the same manner as the organic EL device 1-1 except that the compounds of the hole transport layer and the light emitting layer were replaced with the compounds shown in Table 1. The structure of the compound used above is shown below.

<Evaluation of organic EL elements 1-1 to 1-19>
The organic EL devices 1-1 to 1-19 produced as described below were evaluated, and the results are shown in Table 2.

(External quantum efficiency)
With respect to the produced organic EL device, the external extraction quantum efficiency (%) was measured when a constant current of ^2.5 mA / cm ² was applied at 23 ° C. in a dry nitrogen gas atmosphere.

(Lm / W)
Using the luminance measured with a spectral radiance meter CS-1000 (manufactured by Minolta), lm / W was obtained from the following equation.
lm / W = (brightness (cd / m ² ) × π) / (current density (A / m ² ) × voltage (V))
(Aging degradation)
After storing the organic EL device at 50 ° C. for 7 days, the external extraction quantum efficiency was measured by the above-described external extraction quantum efficiency measurement method.

  The measurement results of the luminous efficiency, lm / W, and deterioration over time are expressed as relative values when the measured value of the organic EL element 1-1 is set to 100 for the organic EL elements 1-1 to 1-12. 1-13 to 1-19 are represented by relative values when the organic EL element 1-13 is set to 100.

  From Table 2, it was found that the organic EL device of the present invention was excellent in the external extraction quantum efficiency and lm / W, and the deterioration of the external extraction quantum efficiency with time was suppressed. In addition, organic EL elements 1-6, 1-10, and 1-18 of the present invention have less suppression of deterioration over time than the comparative organic EL element 1-1, but have an external quantum efficiency and 1 m / m It can be seen that W is greatly improved.

Example 2
<Preparation of organic EL elements 2-1 to 2-4>
A 100 mm × 100 mm × 1.1 mm glass substrate as an anode is patterned on a substrate (NA45, manufactured by NH Techno Glass Co., Ltd.) on which 100 nm of ITO (indium tin oxide) is formed, and then a transparent support provided with this ITO transparent electrode is provided. The substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and washed with UV ozone for 5 minutes. This transparent support substrate was fixed to a substrate holder of a commercially available vacuum evaporation apparatus, while 200 mg of CuPc was placed in a molybdenum resistance heating boat, 200 mg of 1-56 was placed in another molybdenum resistance heating boat, and another molybdenum resistance heating boat was placed. 200 mg of CBP was placed in a heating boat, 200 mg of bathocuproine (BCP) was placed in another molybdenum resistance heating boat, 100 mg of Ir-1 was placed in another molybdenum resistance heating boat, and Alq ₃ was placed in another molybdenum resistance heating boat. Was placed in a vacuum evaporation apparatus.

Next, after the pressure in the vacuum chamber was reduced to 4 × 10 ⁻⁴ Pa, the heating boat containing CuPc was energized and heated, and was vapor-deposited on the transparent support substrate at a vapor deposition rate of 0.1 nm / sec. Layers were provided. Further, the heating boat containing 1-56 was energized and heated, and vapor-deposited on the second hole transport layer at a vapor deposition rate of 0.1 nm / sec to provide a first hole transport layer. Further, the heating boat containing CBP and Ir-1 was energized and heated, and co-deposited on the first hole transport layer at a deposition rate of 0.2 nm / sec and 0.012 nm / sec, respectively, to form a light emitting layer. Was provided. In addition, the substrate temperature at the time of vapor deposition was room temperature. Further, an electric current is applied to the heating boat containing the BCP, and the heating boat is heated to be deposited on the light emitting layer at a deposition rate of 0.1 nm / sec to provide a 10 nm-thick electron transport layer also serving as a hole blocking layer. Was. On top of that, the heating boat containing Alq ₃ was further energized and heated, and was vapor-deposited on the electron transport layer at a vapor deposition rate of 0.1 nm / sec to further provide an electron injection layer having a thickness of 40 nm. . In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Subsequently, 0.5 nm of lithium fluoride and 110 nm of aluminum were deposited to form a cathode, and an organic EL device 2-1 was produced. Other organic EL devices shown in Table 3 were produced in the same manner as the organic EL device 2-1 except that the compounds of the hole transport layer and the light emitting layer were replaced with the compounds shown in Table 3. The structure of the compound used above is shown below.

<Evaluation of organic EL elements 2-1 to 2-4>
The evaluation of the organic EL device was performed in the same manner as in Example 1.

  The measurement results of the external extraction quantum efficiency, lm / W, and the deterioration with the lapse of time show that the organic EL elements 2-1, 2-2, 2-3, and 2-4 have the organic EL elements 1-2, 1-8, and 2-4, respectively. 1-15 and 1-10 were expressed as relative values when 100 was set. Table 4 shows the results.

  From Table 4, it can be seen that the provision of the second hole transporting layer satisfying 0.1 eV <Ip1-Ip4 <0.7 eV makes the organic EL device of the present invention more excellent in luminous efficiency and lm / W, and further more. It was found that deterioration with time was suppressed.

Example 3
The green and blue light-emitting organic EL devices of the present invention prepared in the above-described examples and the red light-emitting organic EL device prepared in the same manner except that the phosphorescent compound of the green light-emitting organic EL device of the present invention was replaced with Btp2Ir (acac). Were arranged side by side on the same substrate to produce an active matrix type full-color display device shown in FIG. FIG. 2 shows only a schematic diagram of the display section A of the manufactured full-color display device. That is, on the same substrate, a wiring portion including a plurality of scanning lines 5 and data lines 6 and a plurality of pixels 3 (pixels in a red region, pixels in a green region, pixels in a blue region, and the like) are arranged side by side. The scanning lines 5 and the plurality of data lines 6 of the wiring portion are each made of a conductive material, and the scanning lines 5 and the data lines 6 are orthogonal to each other in a grid and are connected to the pixels 3 at orthogonal positions (details). Is not shown). The plurality of pixels 3 are driven by an active matrix method provided with an organic EL element corresponding to each emission color, and a switching transistor and a driving transistor, which are active elements, and a scanning signal is applied from a scanning line 5. Then, an image data signal is received from the data line 6 and light is emitted according to the received image data. By appropriately arranging the red, green, and blue pixels in this manner, full-color display can be achieved.

  By driving the full-color display device, a clear full-color moving image display with high luminance and good durability was obtained.

FIG. 2 is a schematic diagram illustrating an example of a display device including an organic EL element. It is a schematic diagram of a display part. It is a schematic diagram of a pixel. It is a schematic diagram of a passive matrix type full color display device.

Explanation of reference numerals

Reference Signs List 1 display 3 pixel 5 scanning line 6 data line 7 power supply line 10 organic EL element 11 switching transistor 12 drive transistor 13 capacitor A display unit B control unit

Claims (56)

In a light-emitting element having at least a light-emitting layer containing a phosphorescent compound and a hole-transport layer containing a hole-transport material adjacent to the light-emitting layer,
The organic electroluminescent device, wherein the hole transporting material has a 0-0 band in a phosphorescence spectrum of 300 nm to 450 nm and a molecular weight of 550 or more. The organic electroluminescence device according to claim 1, wherein the hole transport material has an ionization potential Ip1 (eV) of 5.00 to 5.70 eV. The organic electroluminescent device according to claim 1, wherein the ionization potential Ip1 (eV) of the hole transport material and the ionization potential Ip3 (eV) of the phosphorescent compound satisfy the following expression.
−0.1 eV ≦ Ip3-Ip1 ≦ 0.5 eV 4. The electron affinity Ea1 (eV) of the hole transport material and the excited triplet level T3 (eV) of the phosphorescent compound satisfy the following expression. The organic electroluminescent device according to the above.
0.5 eV <T3-Ea1 <1.3 eV The organic electroluminescence device according to any one of claims 1 to 4, wherein the phosphorescent compound has a phosphorescent maximum emission wavelength in a range from 380 nm to 480 nm. A hole transporting layer adjacent to the hole transporting layer and opposite to the light emitting layer, wherein an ionization potential Ip4 (eV) of a hole transporting material contained in the hole transporting layer and the hole The organic electroluminescence device according to any one of claims 1 to 5, wherein the ionization potential Ip1 (eV) of the transport material satisfies the following expression.
0.1 eV <Ip1-Ip4 <0.7 eV The organic electroluminescent device according to claim 6, wherein the thickness of the hole transport layer adjacent to the light emitting layer is 5 nm to 20 nm. The organic electroluminescent device according to any one of claims 1 to 7, wherein the light emitting layer further contains a host compound. The organic electroluminescence device according to claim 8, wherein the ionization potential Ip1 (eV) of the hole transport material and the ionization potential Ip2 (eV) of the host compound satisfy the following expression.
0.3 eV <Ip2-Ip1 <1.0 eV 10. The organic electroluminescence device according to claim 8, wherein the electron affinity Ea1 (eV) of the hole transport material and the electron affinity Ea2 (eV) of the host compound satisfy the following expression.
0.1 eV <Ea2-Ea1 <0.8 eV The organic electroluminescent device according to any one of claims 8 to 10, wherein the 0-0 band of the phosphorescence spectrum of the host compound is from 300 nm to 450 nm. The organic electroluminescence device according to claim 8, wherein the host compound is a carbazole derivative. 13. The organic electroluminescent device according to claim 12, wherein the carbazole derivative is a compound represented by the following general formula 11.

(In the formula, R _{1001 to} R ₁₀₁₃ each independently represent a hydrogen atom or a substituent, but at least one represents a substituent.) 13. The organic electroluminescence device according to claim 12, wherein the carbazole derivative is a compound represented by the following general formula 12.

(In the formula, R ₁₀₂₁ represents an alkyl group, a cycloalkyl group, or a fluorinated alkyl group, and R _{1022 to} R ₁₀₂₉ each independently represent a hydrogen atom or a substituent. Represents.) 13. The organic electroluminescent device according to claim 12, wherein the carbazole derivative is a compound represented by the following general formula 13.

(Wherein, R _{1031 to} R ₁₀₄₆ each independently represent a hydrogen atom or a substituent, and L ₃ represents a divalent linking group or a direct bond. In the case of a direct bond, R ₁₀₃₇ and R ₁₀₃₈ , R ₁₀₄₅ or R ₁₀₄₆ represents a substituent.) The organic electroluminescent device according to claim 12, wherein the carbazole derivative is a compound represented by the following general formula 14.

(In the formula, R _{1051 to} R ₁₀₆₃ each independently represent a hydrogen atom or a substituent, and any of R ₁₀₅₇ , R ₁₀₅₈ , R ₁₀₆₂ , and R ₁₀₆₃ represents a substituent.) The organic electroluminescent device according to claim 12, wherein the carbazole derivative is a compound represented by the following general formula 15.

(Wherein, R _{1071 to} R ₁₀₇₉ each independently represent a hydrogen atom or a substituent, and either R ₁₀₇₂ or R ₁₀₇₃ represents a substituent. N represents an integer of 1 to 8. ) The organic electroluminescent device according to any one of claims 1 to 17, wherein the hole transport material is a triarylamine compound. The organic electroluminescent device according to claim 18, wherein the triarylamine compound is a compound represented by the following general formula 1.

(In the formula, Ar _{11 to} Ar ₁₃ each represent an arylene group or a heteroarylene group. R _{11 to} R ₁₃ each independently represent a hydrogen atom or a substituent, and at least one represents a substituent. .) The organic electroluminescence device according to claim 18, wherein the triarylamine compound is a compound represented by the following general formula 2.

(In the formula, Ar ₃₀₁ represents an aryl group or a heteroaryl group which may have a substituent, B represents the following general formula 3, and n represents an integer of 1 to 3.)

(Wherein, Z ₁ and Z ₂ each independently represent an atomic group necessary for forming an aromatic carbocyclic ring or an aromatic heterocyclic ring, and X _{1 to} X ₄ each independently represent C It represents -R _301, N, O, S, a, R ₃₀₁ represents a hydrogen atom, or represents a substituent, at least one of X ₁ to X ₄ represents a C-R _301, R ₃₀₁ at that time Represents a substituent.) The organic electroluminescence device according to claim 18, wherein the triarylamine compound is at least one of compounds represented by the following general formulas 4-1 and 4-2.

(Wherein, Ar _{801 to} Ar ₈₀₃ each represent an aryl group or a heteroaryl group which may have a substituent. R _{801 to} R ₈₂₇ each represent a hydrogen atom or a substituent; provided that R ₈₀₁ and R ₈₀₂ are each a substituent. Is a substituent, any of R ₈₀₃ and R ₈₀₄ is a substituent, and any of R ₈₀₅ and R ₈₀₆ is a substituent; any of R _{807 to} R ₈₁₀ is a substituent; and R _{811 to} R ₈₁₄ Is a substituent, and any of R _{815 to} R ₈₁₈ represents a substituent.) 19. The organic electroluminescent device according to claim 18, wherein the triarylamine compound is at least one of the compounds represented by the following general formula 5.

(Wherein, R _{960 to} R ₉₇₆ each independently represent a hydrogen atom or a substituent. However, any of R ₉₆₀ and R ₉₆₁ represents a substituent, and any of R ₉₆₃ and R ₉₆₄ represents a substituent. L ₁ represents a divalent linking group or a direct bond) 19. The organic electroluminescent device according to claim 18, wherein the triarylamine compound is at least one of the compounds represented by the following general formula 6.

(In the formula, R _{960 to} R ₉₇₆ each independently represent a hydrogen atom or a substituent. L ₂ represents a divalent alkylene group, a cycloalkylene group, or a fluorinated alkylene group.) 19. The organic electroluminescent device according to claim 18, wherein the triarylamine compound is at least one of the compounds represented by the following general formula 7.

(In the formula, B ₂ represents the following general formula 8, and Ar _{501 to} Ar ₅₀₃ each independently represent an aryl group or a heteroaryl group which may have a substituent. N is an integer of 1 to 3. Represent)

(Wherein, X _{5 to} X ₈ each independently represent N or C—R ₅₀₁ , and R ₅₀₁ represents a hydrogen atom or a substituent. At least one of X ₅ and X ₆ represents C— R ₅₀₁ , at least one of R ₅₀₁ represents a substituent, and at least one of X ₇ and X ₈ is _{CR 501} , and at least one of R ₅₀₁ represents a substituent.) 19. The organic electroluminescent device according to claim 18, wherein the triarylamine compound is at least one of the compounds represented by the following general formula 9.

(Wherein, R _{833 to} R ₈₇₄ each independently represent a hydrogen atom or a substituent. However, one of R ₈₃₃ and R ₈₃₄ represents a substituent, and one of R ₈₃₅ and R _{836 Represents} a substituent, one of R ₈₃₇ and R ₈₃₈ represents a substituent, one of R ₈₃₉ and R ₈₄₀ represents a substituent, and one of R ₈₄₁ and R ₈₄₂ represents a substituent. , R ₈₄₃ or R ₈₄₄ represents a substituent.) The organic electroluminescence according to claim 18, wherein the triarylamine compound has at least one of terminal groups represented by the following general formulas 10-1, 10-2, 10-3, and 10-4. element.

(Wherein X ₉ and X ₁₀ each independently represent N, O, S, or C—R ₆₁₁ , and R ₆₁₁ represents a hydrogen atom or a substituent, and at least X ₉ and X ₁₀ One is C-R ₆₁₁ , wherein R ₆₁₁ is a substituent, and Z ₆₀₁ represents an atom group necessary for forming an aromatic carbon ring or an aromatic hetero ring together with X ₉ and X _10. R _{601 to} R ₆₀₅ each independently represent a hydrogen atom or a substituent, and at least one of R ₆₀₁ and R ₆₀₅ is a substituent, and R _{606 to} R ₆₁₀ each independently represent a substituent. .) In a light-emitting element having at least a light-emitting layer containing a phosphorescent compound and a hole-transport layer containing a hole-transport material adjacent to the light-emitting layer,
The organic electroluminescent device, wherein the hole transport material is a triarylamine compound represented by the following general formula 1.

(In the formula, Ar _{11 to} Ar ₁₃ each represent an arylene group or a heteroarylene group. R _{11 to} R ₁₃ each independently represent a hydrogen atom or a substituent, and at least one represents a substituent. .) In a light-emitting element having at least a light-emitting layer containing a phosphorescent compound and a hole-transport layer containing a hole-transport material adjacent to the light-emitting layer,
The organic electroluminescent device, wherein the hole transport material is a triarylamine compound represented by the following general formula 2.

(In the formula, Ar ₃₀₁ represents an aryl group or a heteroaryl group which may have a substituent, B represents the following general formula 3, and n represents an integer of 1 to 3.)

(Wherein, Z ₁ and Z ₂ each independently represent an atomic group necessary for forming an aromatic carbocyclic ring or an aromatic heterocyclic ring, and X _{1 to} X ₄ each independently represent C It represents -R _301, N, O, S, a, R ₃₀₁ represents a hydrogen atom, or represents a substituent, at least one of X ₁ to X ₄ represents a C-R _301, R ₃₀₁ at that time Represents a substituent.) In a light-emitting element having at least a light-emitting layer containing a phosphorescent compound and a hole-transport layer containing a hole-transport material adjacent to the light-emitting layer,
An organic electroluminescent device, wherein the hole transporting material is at least one of triarylamine compounds represented by the following general formulas 4-1 and 4-2.

(Wherein, Ar _{801 to} Ar ₈₀₃ each represent an aryl group or a heteroaryl group which may have a substituent. R _{801 to} R ₈₂₇ each represent a hydrogen atom or a substituent; provided that R ₈₀₁ and R ₈₀₂ are each a substituent. Is a substituent, any of R ₈₀₃ and R ₈₀₄ is a substituent, and any of R ₈₀₅ and R ₈₀₆ is a substituent; any of R _{807 to} R ₈₁₀ is a substituent; and R _{811 to} R ₈₁₄ Is a substituent, and any of R _{815 to} R ₈₁₈ represents a substituent.) In a light-emitting element having at least a light-emitting layer containing a phosphorescent compound and a hole-transport layer containing a hole-transport material adjacent to the light-emitting layer,
An organic electroluminescent device, wherein the hole transport material is a triarylamine compound represented by the following general formula 5.

(Wherein, R _{960 to} R ₉₇₆ each independently represent a hydrogen atom or a substituent. However, any of R ₉₆₀ and R ₉₆₁ represents a substituent, and any of R ₉₆₃ and R ₉₆₄ represents a substituent. L ₁ represents a divalent linking group or a direct bond) In a light-emitting element having at least a light-emitting layer containing a phosphorescent compound and a hole-transport layer containing a hole-transport material adjacent to the light-emitting layer,
An organic electroluminescent device, wherein the hole transport material is a triarylamine compound represented by the following general formula 6.

(In the formula, R _{960 to} R ₉₇₆ each independently represent a hydrogen atom or a substituent. L ₂ represents a divalent alkylene group, a cycloalkylene group, or a fluorinated alkylene group.) In a light-emitting element having at least a light-emitting layer containing a phosphorescent compound and a hole-transport layer containing a hole-transport material adjacent to the light-emitting layer,
The organic electroluminescent device, wherein the hole transport material is a triarylamine compound represented by the following general formula 7.

(In the formula, B ₂ represents the following general formula 8, and Ar _{501 to} Ar ₅₀₃ each independently represent an aryl group or a heteroaryl group which may have a substituent. N is an integer of 1 to 3. Represent)

(Wherein, X _{5 to} X ₈ each independently represent N or C—R ₅₀₁ , and R ₅₀₁ represents a hydrogen atom or a substituent. At least one of X ₅ and X ₆ represents C— R ₅₀₁ , at least one of R ₅₀₁ represents a substituent, and at least one of X ₇ and X ₈ is _{CR 501} , and at least one of R ₅₀₁ represents a substituent.) In a light-emitting element having at least a light-emitting layer containing a phosphorescent compound and a hole-transport layer containing a hole-transport material adjacent to the light-emitting layer,
The organic electroluminescent device, wherein the hole transport material is a triarylamine compound represented by the following general formula 9.

(Wherein, R _{833 to} R ₈₇₄ each independently represent a hydrogen atom or a substituent. However, one of R ₈₃₃ and R ₈₃₄ represents a substituent, and one of R ₈₃₅ and R _{836 Represents} a substituent, one of R ₈₃₇ and R ₈₃₈ represents a substituent, one of R ₈₃₉ and R ₈₄₀ represents a substituent, and one of R ₈₄₁ and R ₈₄₂ represents a substituent. , R ₈₄₃ or R ₈₄₄ represents a substituent.) In a light-emitting element having at least a light-emitting layer containing a phosphorescent compound and a hole-transport layer containing a hole-transport material adjacent to the light-emitting layer,
The organic electroluminescence, wherein the hole transport material is a triarylamine compound having at least one of terminal groups represented by the following general formulas 10-1, 10-2, 10-3, and 10-4. element.

(Wherein X ₉ and X ₁₀ each independently represent N, O, S, or C—R ₆₁₁ , and R ₆₁₁ represents a hydrogen atom or a substituent, and at least X ₉ and X ₁₀ One is C-R ₆₁₁ , wherein R ₆₁₁ is a substituent, and Z ₆₀₁ represents an atom group necessary for forming an aromatic carbon ring or an aromatic hetero ring together with X ₉ and X _10. R _{601 to} R ₆₀₅ each independently represent a hydrogen atom or a substituent, and at least one of R ₆₀₁ and R ₆₀₅ is a substituent, and R _{606 to} R ₆₁₀ each independently represent a substituent. .) The organic electroluminescent device according to any one of claims 27 to 34, wherein the hole transport material has a molecular weight of 550 or more. The organic electroluminescence device according to any one of claims 27 to 35, wherein the hole transport material has an ionization potential Ip1 (eV) of 5.00 to 5.70 eV. 37. The organic electroluminescent device according to claim 27, wherein the ionization potential Ip1 (eV) of the hole transport material and the ionization potential Ip3 (eV) of the phosphorescent compound satisfy the following expression. Luminescent element.
−0.1 eV ≦ Ip3-Ip1 ≦ 0.5 eV The electron affinity Ea1 (eV) of the hole transporting material and the excited triplet level T3 (eV) of the phosphorescent compound satisfy the following expression. The organic electroluminescent device according to the above.
0.5 eV <T3-Ea1 <1.3 eV The organic electroluminescence device according to any one of claims 27 to 38, wherein the phosphorescent compound has a phosphorescent maximum emission wavelength at 380 to 480 nm. A hole transporting layer adjacent to the hole transporting layer and opposite to the light emitting layer, wherein an ionization potential Ip4 (eV) of a hole transporting material contained in the hole transporting layer and the hole The organic electroluminescence device according to any one of claims 27 to 39, wherein the ionization potential Ip1 (eV) of the transport material satisfies the following expression.
0.1 eV <Ip1-Ip4 <0.7 eV 41. The organic electroluminescence device according to claim 40, wherein the thickness of the hole transport layer adjacent to the light emitting layer is 5 nm to 20 nm. The organic electroluminescence device according to any one of claims 27 to 41, wherein the light emitting layer further contains a host compound. The organic electroluminescence according to any one of claims 27 to 42, wherein an ionization potential Ip1 (eV) of the hole transport material and an ionization potential Ip2 (eV) of the host compound satisfy the following expression. element.
0.3 eV <Ip2-Ip1 <1.0 eV The organic electroluminescence according to any one of claims 27 to 43, wherein an electron affinity Ea1 (eV) of the hole transport material and an electron affinity Ea2 (eV) of the host compound satisfy the following expression. element.
0.1 eV <Ea2-Ea1 <0.8 eV The organic electroluminescent device according to any one of claims 27 to 44, wherein the 0-0 band of the phosphorescence spectrum of the host compound is from 300 nm to 450 nm. The organic electroluminescent device according to any one of claims 27 to 45, wherein the host compound is a carbazole derivative. 47. The organic electroluminescent device according to claim 46, wherein the carbazole derivative is a compound represented by the following general formula 11.

(In the formula, R _{1001 to} R ₁₀₁₃ each independently represent a hydrogen atom or a substituent, but at least one represents a substituent.) 47. The organic electroluminescent device according to claim 46, wherein the carbazole derivative is a compound represented by the following general formula 12.

(In the formula, R ₁₀₂₁ represents an alkyl group, a cycloalkyl group, or a fluorinated alkyl group, and R _{1022 to} R ₁₀₂₉ each independently represent a hydrogen atom or a substituent. Represents.) 47. The organic electroluminescent device according to claim 46, wherein the carbazole derivative is a compound represented by the following general formula 13.

(Wherein, R _{1031 to} R ₁₀₄₆ each independently represent a hydrogen atom or a substituent, and L ₃ represents a divalent linking group or a direct bond. In the case of a direct bond, R ₁₀₃₇ and R ₁₀₃₈ , R ₁₀₄₅ or R ₁₀₄₆ represents a substituent.) 47. The organic electroluminescent device according to claim 46, wherein the carbazole derivative is a compound represented by the following general formula 14.

(In the formula, R _{1051 to} R ₁₀₆₃ each independently represent a hydrogen atom or a substituent, and any of R ₁₀₅₇ , R ₁₀₅₈ , R ₁₀₆₂ , and R ₁₀₆₃ represents a substituent.) 47. The organic electroluminescent device according to claim 46, wherein the carbazole derivative is a compound represented by the following general formula 15.

(Wherein, R _{1071 to} R ₁₀₇₉ each independently represent a hydrogen atom or a substituent, and either R ₁₀₇₂ or R ₁₀₇₃ represents a substituent. N represents an integer of 1 to 8. ) The organic electroluminescence device according to any one of claims 1 to 51, wherein the hole transport layer is formed by vapor deposition. The organic electroluminescent device according to any one of claims 1 to 51, wherein the hole transport layer is formed by a wet process. A display device comprising the organic electroluminescence device according to claim 1. A lighting device comprising the organic electroluminescent element according to claim 1. A display device comprising: the lighting device according to claim 55; and a liquid crystal element as a display unit.

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