Aromatic amine derivative, and organic electroluminescent element using same

Abstract

An aromatic amine derivative represented by formula (1): ##STR00001##
wherein HAr.sup.1, Ar.sup.2, L.sup.1, L.sup.2, and L.sup.3 are as defined in the specification, is useful as a material for constituting an organic EL device and realizes an organic EL device having a high efficiency and a long lifetime even when driving at a low voltage.

Claims

1. An organic electroluminescence device comprising an anode, a cathode, and at least one organic thin film layers between the anode and the cathode, wherein: the at least one organic thin film layers comprises a light emitting layer and a hole transporting layer between the anode and the light emitting layer; the hole transporting layer comprises an anode side first hole transporting layer and a cathode side second hole transporting layer; and any of the anode side first hole transporting layer and the cathode side second hole transporting layer comprise an aromatic amine derivative represented by formula (1): ##STR00082## wherein HAr.sup.1 represents a group selected from formulae (2) to (4): ##STR00083## in formulae (2) to (4), n represents an integer of 0 to 4; and each R independently represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 3 to 50 ring atoms, a halogen atom, a substituted or unsubstituted fluoroalkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 50 ring carbon atoms, or a cyano group, when more than one R is present, the groups R may be the same or different; L.sup.1 to L.sup.2 may be the same or different and each independently represents a group represented by formula (6): ##STR00084## and L.sup.3 represents a single bond; Ar.sup.2 represents a group selected from formulae (8) and (10), provided that Ar.sup.2does not include a carbazole and a substitited or unsubstituted animo group: ##STR00085## in formulae (8) to (11), n represents an integer of 0 to 4; and each R independently represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 3 to 50 ring atoms, a halogen atom, a substituted or unsubstituted fluoroalkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 50 ring carbon atoms, or a cyano group, when more than one R is present, the groups R may be the same or different.

2. The organic electroluminescence according to claim 1, wherein the aromatic amine derivative is represented by formula (12): ##STR00086## wherein HAr.sup.1, Ar.sup.2, L.sup.2, and L.sup.3 are as defined in formula (1).

3. The organic electroluminescence device according to claim 1, wherein HAr1 does not include a carbazole skeleton and a substituted or unsubstituted amino group.

4. The organic electroluminescence device according to claim 1, wherein n in formulae (2) and (4) is 0.

5. The organic electroluminescence device according to claim 1, wherein n in formulae (8) and (10) is 0.

6. The organic electroluminescence device according to claim 2, wherein HAr.sup.1 does not include a carbazole skeleton and a substituted or unsubstituted amino group.

7. The organic electroluminescence device according to claim 2, wherein n in formulae (2) and (4) is 0.

8. The organic electroluminescence device according to claim 2, wherein n in formulae (8) and (10) is 0.

9. The organic electroluminescence device according to claim 1, wherein the cathode side second hole transporting layer comprises the aromatic amine derivative.

10. The organic electroluminescence device according to claim 1, wherein the organic electroluminescence device comprises a hole injecting layer between the anode and the anode side first hole transporting layer.

11. The organic electroluminescence device according to claim 1, wherein each of L.sup.1 and L.sup.2 is a p-phenylene group.

12. The organic electroluminescence device according to claim 2, wherein L.sup.2 is a p-phenylene group.

13. The organic electroluminescence device according to claim 1, wherein one of HAr.sup.1 and Ar.sup.2 is a 4-dibenzofuranyl group.

14. The organic electroluminescence device according to claim 1, wherein one of HAr.sup.1 and Ar.sup.2 is a 2-dibenzofuranyl group.

15. The organic electroluminescence device according to claim 1, wherein HAr.sup.1 and Ar.sup.2 are both 4-dibenzofuranyl groups.

16. The organic electroluminescence device according to claim 1, wherein HAr.sup.1 and Ar.sup.2 are both 2-dibenzofuranyl groups.

Description

EXAMPLES

(1) The present invention will be described below in more detail with reference to the examples. However, it should be noted that the scope of the invention is not limited thereto.

Intermediate Synthesis 1-1

Synthesis of Intermediate 1-1

(2) Under an argon atmosphere, 750 ml of dry toluene was added to a mixture of 50.8 g (150.0 mmol) of 2-bromotriphenylene, 25.4 g (150.0 mmol) of diphenylamine, and 28.8 g (300.0 mmol) of t-butoxysodium, and the resultant mixture was stirred. After further adding 674 mg (3.0 mmol) of palladium acetate and 607 mg (3.0 mmol) of tri-t-butylphosphine, the mixture was allowed to react at 80° C. for 8 h.

(3) After cooling, the reaction mixture was filtered through celite/silica gel. The filtrate was concentrated under reduced pressure. The obtained residue was recrystallized from toluene and the crystal was collected by filtration and dried to obtain 48.3 g of a white solid, which was identified as the intermediate 1-1 by FD-MS analysis (Field Desorption Mass Spectrometry Analysis) (yield: 82%).

(4) ##STR00058##

Intermediate Synthesis 1-2

Synthesis of Intermediate 1-2

(5) Under an argon atmosphere, 500 ml of toluene and 300 ml of ethyl acetate were added to 20.0 g (50.6 mmol) of the intermediate 1-1, and the resultant mixture was stirred. After adding 18.0 g (101.2 mmol) of N-bromosuccinimide, the mixture was allowed to react at room temperature for 24 h. After further adding 1.0 g (5.6 mmol) of N-bromosuccinimide, the reaction was continued at room temperature for 3 h.

(6) After adding 300 ml of water, the reaction mixture was extracted with toluene. The organic layer was washed with a saturated saline, dried over MgSO.sub.4, filtrate, and concentrated. The obtained residue was recrystallized from toluene and the crystal was collected by filtration and dried to obtain 24.4 g of a white solid, which was identified as the intermediate 1-2 by FD-MS analysis (yield: 87%).

(7) ##STR00059##

Intermediate Synthesis 1-3

Synthesis of Intermediate 1-3

(8) Under an argon atmosphere, 500 ml of toluene, 300 ml of dimethoxyethane, and 160 ml (320.0 mmol) of a 2 M aqueous solution of Na.sub.2CO.sub.3 were added to a mixture of 49.1 g (160.0 mmol) of 2-bromotriphenylene, 25.0 g (160.0 mmol) of 4-chlorophenylboronic acid, and 3.7 g (3.20 mmol) of Pd[PPh.sub.3].sub.4, and the resultant mixture was stirred for 30 h while refluxing under heating.

(9) After the reaction, the obtained mixture was cooled to room temperature and extracted with dichloromethane in a separatory funnel. The organic layer was dried over MgSO.sub.4, and then filtered and concentrated. The obtained residue was recrystallized from toluene and the crystal was collected by filtration and dried to obtain 49.0 g of a white solid, which was identified as the intermediate 1-3 by FD-MS analysis (yield: 90%).

(10) ##STR00060##

Intermediate Synthesis 1-4

Synthesis of Intermediate 1-4

(11) In the same manner as in Intermediate Synthesis 1-1 except for using 30.0 g of the intermediate 1-3 in place of 2-bromotriphenylene, 30.0 g of a white solid was obtained, which was identified as the intermediate 1-4 by FD-MS analysis (yield: 71%).

(12) ##STR00061##

Intermediate Synthesis 1-5

Synthesis of Intermediate 1-5

(13) In the same manner as in Intermediate Synthesis 1-2 except for using 30.0 g of the intermediate 1-4 in place of the intermediate 1-1, 25.4 g of a white solid was obtained, which was identified as the intermediate 1-5 by FD-MS analysis (yield: 63%).

(14) ##STR00062##

Intermediate Synthesis 2-1

Synthesis of Intermediate 2-1

(15) Under an argon atmosphere, 150 ml of toluene, 150 ml of dimethoxyethane, and 150 ml (300.0 mmol) of a 2 M aqueous solution of Na.sub.2CO.sub.3 were added to a mixture of 28.3 g (100.0 mmol) of 4-iodobromobenzene, 22.3 g (105.0 mmol) of dibenzofuran-4-boronic acid, and 2.31 g (2.00 mmol) of Pd[PPh.sub.3].sub.4, and the resultant mixture was stirred for 10 h while refluxing under heating.

(16) After the reaction, the obtained mixture was cooled to room temperature and extracted with dichloromethane in a separatory funnel. The organic layer was dried over MgSO.sub.4, and then filtered and concentrated. The concentrate was purified by silica gel column chromatography to obtain 26.2 g of a white solid, which was identified as the intermediate 2-1 by FD-MS analysis (yield: 81%).

(17) ##STR00063##

Intermediate Synthesis 2-2

Synthesis of Intermediate 2-2

(18) Under an argon atmosphere, 450 ml of toluene, 100 ml of dimethoxyethane, and 110 ml (220.0 mmol) of a 2 M aqueous solution of Na.sub.2CO.sub.3 were added to a mixture of 24.0 g (112.0 mmol) of 4′-bromoacetanilide, 28.6 g (135.0 mmol) of dibenzofuran-4-boronic acid, and 2.6 g (2.24 mmol) of Pd[PPh.sub.3].sub.4, and the resultant mixture was stirred for 10 h while refluxing under heating.

(19) After the reaction, the obtained mixture was cooled to room temperature, and the precipitated crystal was collected by filtration. The collected crystal was dissolved in tetrahydrofuran and filtered through celite/silica gel. The filtrate was concentrated under reduced pressure. The obtained residue was washed with methanol/hexane and dried to obtain 18.0 g of a white solid, which was identified as the intermediate 2-2 by FD-MS analysis (yield: 53%).

(20) ##STR00064##

Intermediate Synthesis 2-3

Synthesis of Intermediate 2-3

(21) A mixture obtained by adding 120 ml of xylene, 1200 ml of water, and 60 ml of ethanol to 18.0 g (59.7 mmol) of the intermediate 2-2 was stirred. After further adding 20.0 g (360.0 mmol) of potassium hydroxide, the resultant mixture was stirred for 10 h while refluxing under heating.

(22) After the reaction, the obtained mixture was cooled to room temperature and extracted with toluene in a separatory funnel. The organic layer was dried over MgSO.sub.4, and then filtered and concentrated. The obtained residue was recrystallized from xylene. The crystal was collected by filtration and dried to obtain 14.7 g of a white solid, which was identified as the intermediate 2-3 by FD-MS analysis (yield: 95%).

(23) ##STR00065##

Intermediate Synthesis 2-4

Synthesis of Intermediate 2-4

(24) Under a nitrogen atmosphere, 1000 ml of acetic acid was added to 150 g (0.89 mol) of dibenzofuran, and dissolved under heating. After further adding 188 g (1.18 mol) of bromine dropwise, the mixture was stirred at room temperature for 20 h. The precipitated crystal was collected by filtration and washed successively with acetic acid and water. The obtained crude product was recrystallized from methanol several times to obtain 66.8 g of a white crystal, which was identified as the intermediate 2-4 by FD-MS analysis (yield: 30%).

(25) ##STR00066##

Intermediate Synthesis 2-5

Synthesis of Intermediate 2-5

(26) Under an argon atmosphere, to 24.7 g (100.0 mmol) of the intermediate 2-4, 400 ml of dry tetrahydrofuran was added, and the mixture was cooled to −40° C. Then, 63 ml (100.0 mmol) of a 1.6 M hexane solution of n-butyllithium was gradually added. The reaction solution was stirred for one hour while heating to 0° C. Then, the reaction solution was cooled again to −78° C., to which a solution of 26.0 g (250.0 mmol) of trimethyl borate in 50 ml of dry tetrahydrofuran was added dropwise. After the dropwise addition, the reaction solution was stirred at room temperature for 5 h. After adding 200 ml of a 1 N hydrochloric acid, the solution was stirred for one hour and then the aqueous layer was removed. The organic layer was dried over MgSO.sub.4, and the solvent was evaporated off under reduced pressure. The obtained solid was washed with toluene to obtain 15.2 g of a white crystal (yield: 72%).

(27) ##STR00067##

Intermediate Synthesis 2-6

Synthesis of Intermediate 2-6

(28) Under an argon atmosphere, 150 ml of toluene, 150 ml of dimethoxyethane, and 150 ml (300.0 mmol) of a 2 M aqueous solution of Na.sub.2CO.sub.3 were added to a mixture of 28.3 g (100.0 mmol) of 4-iodobromobenzene, 22.3 g (105.0 mmol) of the intermediate 2-5, and 2.31 g (2.00 mmol) of Pd[PPh.sub.3].sub.4, and the resultant mixture was stirred for 10 h while refluxing under heating.

(29) After the reaction, the obtained mixture was extracted with dichloromethane in a separatory funnel. The organic layer was dried over MgSO.sub.4, and then filtered and concentrated. The concentrate was purified by silica gel column chromatography to obtain 24.2 g of a white solid, which was identified as the intermediate 2-6 by FD-MS analysis (yield: 75%).

(30) ##STR00068##

Intermediate Synthesis 2-7

Synthesis of Intermediate 2-7

(31) In the same manner as in Intermediate Synthesis 2-5 except for using 26.3 g of 2-bromodibenzothiophene in place of the intermediate 2-4, 14.8 g of a white solid was obtained, which was identified as the intermediate 2-7 by FD-MS analysis (yield: 65%).

(32) ##STR00069##

Intermediate Synthesis 2-8

Synthesis of Intermediate 2-8

(33) Under an argon atmosphere, 250 ml of dry toluene was added to a mixture of 16.9 g (50.0 mmol) of 2-bromotriphenylene, 13.0 g (50.0 mmol) of the intermediate 2-3, and 9.6 g (100.0 mmol) of t-butoxysodium, and the resultant mixture was stirred. After adding 225 mg (1.0 mmol) of palladium acetate and 202 mg (1.0 mmol) of tri-t-butylphosphine, the reaction was allowed to proceed at 80° C. for 8 h.

(34) After cooling, the reaction mixture was filtered through celite/silica gel. The filtrate was concentrated under reduced pressure. The obtained residue was recrystallized from toluene and the crystal was collected by filtration and dried to obtain 19.9 g of a white solid, which was identified as the intermediate 2-8 by FD-MS analysis (yield: 82%).

(35) ##STR00070##

Synthesis Example 1

Production of Aromatic Amine Derivative H1

(36) Under an argon atmosphere, 50 ml of toluene, 25 ml of dimethoxyethane, and 23 ml (46.0 mmol) of a 2 M aqueous solution of Na.sub.2CO.sub.3 were added to a mixture of 8.3 g (15.0 mmol) of the intermediate 1-2, 7.0 g (33.0 mmol) of dibenzofuran-4-boronic acid, and 0.87 g (0.75 mmol) of Pd[PPh.sub.3]4, and the resultant mixture was stirred for 10 h while refluxing under heating.

(37) After the reaction, the obtained mixture was extracted with toluene in a separatory funnel. The organic layer was dried over MgSO.sub.4, and then filtered and concentrated. The concentrate was purified by silica gel column chromatography. The crude product was recrystallized from toluene and the crystal collected by filtration was dried to obtain 7.9 g of a white solid, which was identified as the aromatic amine derivative H1 by FD-MS analysis (yield: 72%).

(38) ##STR00071##

Synthesis Example 2

Production of Aromatic Heterocyclic Derivative H2

(39) In the same manner as in Synthesis Example 1 except for using 7.0 g of the intermediate 2-5 in place of dibenzofuran-4-boronic acid, 6.9 g of a white crystal was obtained, which was identified as the aromatic amine derivative H2 by FD-MS analysis (yield: 63%).

(40) ##STR00072##

Synthesis Example 3

Production of Aromatic Heterocyclic Derivative H3

(41) In the same manner as in Synthesis Example 1 except for using 6.8 g of the intermediate 2-7 in place of dibenzofuran-4-boronic acid, 3.4 g of a white crystal was obtained, which was identified as the aromatic amine derivative H3 by FD-MS analysis (yield: 33%).

(42) ##STR00073##

Synthesis Example 4

Production of Aromatic Heterocyclic Derivative H4

(43) Under an argon atmosphere, 50 ml of dry xylene was added to a mixture of 3.2 g (10.0 mmol) of the intermediate 2-6, 4.9 g (10.0 mmol) of the intermediate 2-8, 0.14 g (0.15 mmol) of Pd.sub.2(dba).sub.3, 0.087 g (0.3 mmol) of P(tBu).sub.3HBF.sub.4, and 1.9 g (20.0 mmol) of t-butoxysodium, and the resultant mixture was refluxed for 8 h under heating.

(44) After the reaction, the reaction liquid was cooled to 50° C. and filtered through celite and silica gel. The filtrate was concentrated and the obtained concentrate was purified by silica gel column chromatography to obtain a white solid. The crude product was recrystallized from toluene to obtain 3.6 g of a white crystal, which was identified as the aromatic heterocyclic derivative H4 by FD-MS analysis (yield: 50%).

(45) ##STR00074##

Synthesis Example 5

Production of Aromatic Heterocyclic Derivative H5

(46) In the same manner as in Synthesis Example 4 except for using 3.1 g of 4-bromoterphenyl in place of the intermediate 2-6, 3.9 g of a white crystal was obtained, which was identified as the aromatic amine derivative H5 by FD-MS analysis (yield: 55%).

(47) ##STR00075##

Synthesis Example 6

Production of Aromatic Heterocyclic Derivative H6

(48) In the same manner as in Synthesis Example 4 except for using 2.7 g 2-bromo-9,9-dimethylfluorene in place of the intermediate 2-6, 3.5 g of a white crystal was obtained, which was identified as the aromatic amine derivative H6 by FD-MS analysis (yield: 52%).

(49) ##STR00076##

Synthesis Example 7

Production of Aromatic Heterocyclic Derivative H7

(50) In the same manner as in Synthesis Example 1 except for using 9.4 g of the intermediate 1-5 in place of the intermediate 1-2, 4.1 g of a white crystal was obtained, which was identified as the aromatic amine derivative H7 by FD-MS analysis (yield: 32%).

(51) ##STR00077##

Synthesis Example 8

Production of Aromatic Heterocyclic Derivative H8

(52) In the same manner as in Synthesis Example 1 except for using 6.8 g of dibenzothiophene-4-boronic acid in place of dibenzofuran-4-boronic acid, 3.0 g of a white crystal was obtained, which was identified as the aromatic amine derivative H8 by FD-MS analysis (yield: 26%).

(53) ##STR00078##

Example 1

Production of Organic EL Device

(54) A glass substrate with an ITO transparent electrode line having a size of 25 mm×75 mm×1.1 mm (manufactured by GEOMATEC Co., Ltd.) was ultrasonically cleaned in isopropyl alcohol for 5 min and then UV (ultraviolet)/ozone cleaned for 30 min.

(55) The cleaned glass substrate with the transparent electrode line was mounted on the substrate holder of a vacuum deposition apparatus. First, the following electron-accepting compound A was vapor-deposited onto the surface on the side where the transparent electrode line was formed so as to cover the transparent electrode, thereby forming a film A having a thickness of 5 nm.

(56) On the film A, the following aromatic amine derivative TPTE as a first hole transporting material was vapor-deposited to form a first hole transporting layer having a thickness of 65 nm.

(57) Successively after the formation of the first hole transporting layer, the aromatic amine derivative H1 as a second hole transporting material was vapor-deposited to form a second hole transporting layer having a thickness of 10 nm.

(58) On the hole transporting layer, the compound host1-X as a first host material, the compound host2-X as a second host material, and Ir(bzq).sub.3 as a phosphorescent dopant material were co-deposited, thereby forming a green-emitting light emitting layer having a thickness of 25 nm. The concentration of the phosphorescent dopant material was 10% by mass, the concentration of the first host material was 45% by mass, and the concentration of the second host material was 45% by mass.

(59) Next, on the phosphorescent light emitting layer, a film of the compound C having a thickness of 35 nm, a LiF film having a thickness of 1 nm, and a metallic Al film having a thickness of 80 nm were successively deposited to form an cathode. The electron injecting electrode LiF was formed at a film-forming speed of 1 Å/min.

(60) ##STR00079## ##STR00080##

Examples 2 to 8

Production of Organic EL Device

(61) Each organic EL device of Examples 2 to 8 was produced in the same manner as in Example 1 except for using each aromatic amine derivative listed in Table 1 as the second hole transporting material.

Comparative Examples 1 and 2

Production of organic EL device

(62) Each organic EL device of Comparative Examples 1 and 2 was produced in the same manner as in Example 1 except for using each of the following comparative compounds 1 and 2 as the second hole transporting material. The comparative compound 1 is described in Patent Document 6 (paragraph 104).

(63) ##STR00081##
Evaluation of Emission Performance of Organic EL Device

(64) Each organic EL device thus produced was measured for the luminance (L) and the current density by allowing the device to emit light under a direct current drive. Using the measured results, the current efficiency (L/J) and the driving voltage (V) at a current density of 10 mA/cm.sup.2 were determined. In addition, the organic EL device was measured for the lifetime at a current density of 50 mA/cm.sup.2. The 80% lifetime is the time taken until the luminance was reduced to 80% of the initial luminance when driving the device at constant current. The results are shown in Table 1.

(65) TABLE-US-00001 TABLE 1 Measured Results Emission Driving First hole Second hole efficiency voltage 80% transporting transporting (cd/A) (V) Lifetime material material @10 mA/cm.sup.2 @10 mA/cm.sup.2 (h) Examples 1 TPTE H1 60.7 3.1 400 2 TPTE H2 61.5 3.1 370 3 TPTE H3 61.2 3.1 350 4 TPTE H4 62.2 3.1 400 5 TPTE H5 59.5 3.1 400 6 TPTE H6 60.5 3.0 350 7 TPTE H7 60.5 3.2 380 8 TPTE H8 60.8 3.1 390 Comparative Examples 1 TPTE comparative 57.6 3.0 380 compound 1 2 TPTE comparative 60.5 3.5 220 compound 2

(66) The results of Table 1 show that an organic EL device having a high efficiency even when driving it at a low voltage and having a long lifetime is obtained by using the aromatic amine derivative of the invention.