Organic electroluminescent compound and organic electroluminescent device comprising the same

Abstract

The present disclosure relates to an organic electroluminescent compound and an organic electroluminescent device comprising the same. By using the organic electroluminescent compound of the present disclosure, an organic electroluminescent device having excellent luminous properties can be produced.

Claims

1. An organic electroluminescent compound of the following formula 1: ##STR00159## wherein Ar.sub.1 to Ar.sub.6 each independently are selected from the group consisting of a substituted or unsubstituted (C1-C30)alkyl, a substituted or unsubstituted (C6-C30)aryl, a substituted or unsubstituted 5- to 30-membered heteroaryl, and a substituted or unsubstituted spiro[fluorene-(C3-C30)cycloalkane]yl; or Ar.sub.1 and Ar.sub.2, Ar.sub.3 and Ar.sub.4, and Ar.sub.5 and Ar.sub.6 may be linked to each other to form a mono- or polycyclic, 3- to 30-membered alicyclic or aromatic ring, whose carbon atom(s) may be replaced with at least one hetero atom selected from nitrogen, oxygen, and sulfur; L.sub.1 is selected from the group consisting of a single bond, a substituted or unsubstituted (C6-C30)arylene, and a substituted or unsubstituted 5- to 30-membered heteroarylene; L.sub.2 is selected from the group consisting of a single bond, a substituted or unsubstituted (C1-C30)alkylene, a substituted or unsubstituted (C6-C30)arylene, and a substituted or unsubstituted 5- to 30-membered heteroarylene, with a proviso that where n is 0, L.sub.2 does not exist; R.sub.1 and R.sub.2 each independently are selected from the group consisting of hydrogen, deuterium, a halogen, a substituted or unsubstituted (C1-C30)alkyl, a substituted or unsubstituted (C6-C30)aryl, a substituted or unsubstituted 5- to 30-membered heteroaryl, a substituted or unsubstituted (C3-C30)cycloalkyl, a substituted or unsubstituted 3- to 7-membered heterocycloalkyl, a substituted or unsubstituted (C6-C30)aryl(C1-C30)alkyl, NR.sub.11R.sub.12, SiR.sub.13R.sub.14R.sub.15, SR.sub.16, OR.sub.17, a cyano, a nitro, and a hydroxyl; or are linked to an adjacent substituent(s) to form a mono- or polycyclic, 3- to 30-membered alicyclic or aromatic ring, whose carbon atom(s) may be replaced with at least one hetero atom selected from nitrogen, oxygen, and sulfur; R.sub.11 to R.sub.17 each independently are selected from the group consisting of hydrogen, deuterium, a halogen, a substituted or unsubstituted (C1-C30)alkyl, a substituted or unsubstituted (C6-C30)aryl, a substituted or unsubstituted 5- to 30-membered heteroaryl, a substituted or unsubstituted 3- to 7-membered heterocycloalkyl, and a substituted or unsubstituted (C3-C30)cycloalkyl; or are linked to an adjacent substituent(s) to form a mono- or polycyclic, 3- to 30-membered alicyclic or aromatic ring, whose carbon atom(s) may be replaced with at least one hetero atom selected from nitrogen, oxygen, and sulfur; m represents an integer of 1 to 2, where m is 2, each of NAr.sub.1Ar.sub.2 may be the same or different; n represents an integer of 0 to 2, where n is 2, each of NAr.sub.3Ar.sub.4 may be the same or different; a represents an integer of 1 to 5, where a is an integer of 2 or more, each of R.sub.1 may be the same or different; b represents an integer of 1 to 4, where b is an integer of 2 or more, each of R.sub.2 may be the same or different; the heteroaryl(ene) contains at least one hetero atom selected from B, N, O, S, Si, and P; and the heterocycloalkyl contains at least one hetero atom selected from O, S, and N.

2. The organic electroluminescent compound according to claim 1, wherein the compound of formula 1 is selected from the group consisting of formula 2 and formula 3: ##STR00160## wherein Ar.sub.1 to Ar.sub.6, L.sub.1, L.sub.2, R.sub.1, R.sub.2, a, b, m, and n are as defined in claim 1.

3. The organic electroluminescent compound according to claim 1, wherein the substituents of the substituted alkyl(ene), the substituted aryl(ene), the substituted heteroaryl(ene), the substituted cycloalkyl, the substituted heterocycloalkyl, the substituted arylalkyl, and the substituted spiro[fluorene-(C3-C30)cycloalkane]yl in Ar.sub.1 to Ar.sub.6, L.sub.1, L.sub.2, R.sub.1, R.sub.2, and R.sub.11 to R.sub.17 each independently are at least one selected from the group consisting of deuterium, a halogen, a cyano, a carboxyl, a nitro, a hydroxyl, a (C1-C30)alkyl, a halo(C1-C30)alkyl, a (C2-C30)alkenyl, a (C2-C30)alkynyl, a (C1-C30)alkoxy, a (C1-C30)alkylthio, a (C3-C30)cycloalkyl, a (C3-C30)cycloalkenyl, a 3- to 7-membered heterocycloalkyl, a (C6-C30)aryloxy, a (C6-C30)arylthio, a 3- to 30-membered heteroaryl unsubstituted or substituted with a (C6-C30)aryl, a (C6-C30)aryl unsubstituted or substituted with a 3- to 30-membered heteroaryl, a tri(C1-C30)alkylsilyl, a tri(C6-C30)arylsilyl, a di(C1-C30)alkyl(C6-C30)arylsilyl, a (C1-C30)alkyldi(C6-C30)arylsilyl, an amino, a mono- or di-(C1-C30)alkylamino, a mono- or di-(C6-C30)arylamino, a (C1-C30)alkyl(C6-C30)arylamino, a (C1-C30)alkylcarbonyl, a (C1-C30)alkoxycarbonyl, a (C6-C30)arylcarbonyl, a di(C6-C30)arylboronyl, a di(C1-C30)alkylboronyl, a (C1-C30)alkyl(C6-C30)arylboronyl, a (C6-C30)aryl(C1-C30)alkyl, and a (C1-C30)alkyl(C6-C30)aryl.

4. The organic electroluminescent compound according to claim 1, wherein Ar.sub.1 to Ar.sub.4 each independently are selected from the group consisting of a substituted or unsubstituted (C6-C25)aryl, a substituted or unsubstituted 5- to 15-membered heteroaryl, and a substituted or unsubstituted spiro[fluorene-(C5-C8)cycloalkane]yl; Ar.sub.5 and Ar.sub.6 each independently are selected from the group consisting of a substituted or unsubstituted (C1-C6)alkyl, and a substituted or unsubstituted (C6-C12)aryl; or may be linked to each other to form a mono- or polycyclic, 5- to 15-membered alicyclic or aromatic ring; L.sub.1 is selected from the group consisting of a single bond, a substituted or unsubstituted (C6-C20)arylene, and a substituted or unsubstituted 5- to 15-membered heteroarylene; L.sub.2 is selected from the group consisting of a single bond, and a substituted or unsubstituted (C6-C12)arylene, with a proviso that where n is 0, L.sub.2 does not exist; and R.sub.1 and R.sub.2 each independently represent hydrogen.

5. The organic electroluminescent compound according to claim 1, wherein Ar.sub.1 to Ar.sub.4 each independently are selected from the group consisting of a (C6-C25)aryl unsubstituted or substituted with a (C1-C6)alkyl or a (C6-C20)aryl; a 5- to 15-membered heteroaryl unsubstituted or substituted with a (C1-C6)alkyl or a (C6-C12)aryl; an unsubstituted spiro[fluorene-cyclopentane]yl; and an unsubstituted spiro[fluorene-cyclohexane]yl; Ar.sub.5 and Ar.sub.6 each independently are selected from the group consisting of an unsubstituted (C1-C6)alkyl, and an unsubstituted (C6-C12)aryl; or may be linked to each other to form a monocyclic, 5- to 15-membered alicyclic ring; L.sub.1 is selected from the group consisting of a single bond, an unsubstituted (C6-C20)arylene, and an unsubstituted 5- to 15-membered heteroarylene; L.sub.2 is selected from the group consisting of a single bond, and an unsubstituted (C6-C12)arylene, with a proviso that where n is 0, L.sub.2 does not exist; and R.sub.1 and R.sub.2 each independently represent hydrogen.

6. The organic electroluminescent compound according to claim 1, wherein the compound of formula 1 is selected from the group consisting of: ##STR00161## ##STR00162## ##STR00163## ##STR00164## ##STR00165## ##STR00166## ##STR00167## ##STR00168## ##STR00169## ##STR00170## ##STR00171## ##STR00172## ##STR00173## ##STR00174## ##STR00175## ##STR00176## ##STR00177## ##STR00178## ##STR00179## ##STR00180## ##STR00181## ##STR00182## ##STR00183## ##STR00184## ##STR00185## ##STR00186## ##STR00187## ##STR00188## ##STR00189##

7. A hole transport material comprising the organic electroluminescent compound according to claim 1.

8. An organic electroluminescent device comprising the organic electroluminescent compound according to claim 1.

9. The organic electroluminescent device according to claim 8, wherein the organic electroluminescent compound is comprised in at least one layer of a light-emitting layer and a hole transport layer.

10. A display device comprising the organic electroluminescent compound according to claim 1.

Description

EXAMPLE 1: PREPARATION OF COMPOUND C-4

(1) ##STR00142##

(2) Preparation of Compound 1-1

(3) 100 g of indanone (757 mmol), 111.6 g of phthalaldehyde (832 mmol), 10.3 g of 20% sodium ethoxide ethyl alcohol solution (151 mmol), and 1300 mL of ethyl alcohol were introduced into a reaction vessel. After the mixture was refluxed for 2 hours, the mixture was cooled to room temperature and stirred overnight. The reaction solution was cooled to 0 C., and the separated solid was filtered and washed with cold methyl alcohol and hexane to obtain 95 g of compound 1-1 (yield: 55%).

(4) Preparation of Compound 1-2

(5) 33.3 g of iodine (144 mmol), 44 g of hypophosphorous acid (660 mmol, 50% aqueous solution), and 2000 mL of acetic acid were introduced into a reaction vessel, and the mixture was stirred at 80 C. for 30 minutes. 95 g of compound 1-1 (413 mmol) was slowly added dropwise thereto and the mixture was stirred under reflux overnight. The reaction solution was cooled to room temperature, and the separated solid was filtered and washed with cold methyl alcohol and hexane to obtain 73 g of compound 1-2 (yield: 82%).

(6) Preparation of Compound 1-3

(7) 30 g of compound 1-2 (139 mmol), 39 g of potassium hydroxide (694 mmol), 2.3 g of potassium iodide (14 mmol), 1.58 g of benzyltriethylammonium chloride (7 mmol), 70 mL of distilled water, and 700 mL of dimethylsulfoxide were introduced into a reaction vessel, and the mixture was stirred at room temperature for 30 minutes. 49 g of methyl iodide (347 mmol) was added thereto and the mixture was stirred at room temperature overnight. The reaction solution was diluted with ethylacetate and washed with distilled water. The extracted organic layer was then dried with magnesium sulfate. The solvent was removed with a rotary evaporator, and the resulting product was purified by column chromatography to obtain 34 g of compound 1-3 (yield: 68%).

(8) Preparation of Compound 1-4

(9) 3 g of compound 1-3 (12 mmol) was dissolved in 50 mL of methylene chloride in a reaction vessel. 1.3 g of bromine (16 mmol) was dissolved in 10 mL of methylene chloride and added to the reaction solution. The mixture was then stirred at room temperature for 2 hours. The reaction solution was diluted with methylene chloride and washed with distilled water. The extracted organic layer was then dried with magnesium sulfate. The solvent was removed with a rotary evaporator, and the separated solid was filtered and washed with cold methyl alcohol to obtain 1.8 g of compound 1-4 (yield: 45%).

(10) Compound 1-4 can also be obtained as follows:

(11) 1.3 g of compound 1-3 (5 mmol), 10 mL of dimethylformamide, and 1.23 g of N-bromosuccinimide (7 mmol) were introduced into a reaction vessel, and the mixture was stirred at room temperature overnight. The reaction solution was diluted with ethylacetate and washed with distilled water. The extracted organic layer was then dried with magnesium sulfate. The solvent was removed with a rotary evaporator, and the separated solid was filtered and washed with cold methyl alcohol to obtain 620 mg of compound 1-4 (yield: 36%).

(12) Preparation of Compound C-4

(13) 10 g of compound 1-4 (31 mmol), 13.7 g of bis-9,9-dimethyl-9H-fluoren-2-ylamine (31 mmol), 1.46 g of tris(dibenzylideneacetone)dipalladium(0) (2 mmol), 2.2 mL of tri-t-butylphosphine (6 mmol, 50% toluene solution), 5.9 g of sodium t-butoxide (62 mmol), and 223 mL of toluene were introduced into a reaction vessel, and the mixture was refluxed for 4 hours. The reaction solution was cooled to room temperature. The solvent was removed with a rotary evaporator, and the resulting product was purified by column chromatography to obtain 10.5 g of compound C-4 (yield: 52%). The properties of compound C-4 are shown in Table 1.

EXAMPLE 2: PREPARATION OF COMPOUND C-5

(14) ##STR00143##

(15) 40 g of compound 1-4 (124 mmol), 44.7 g of N-1,1-biphenyl-4-yl-9,9-dimethyl-9H-fluorene-2-amine (124 mmol), 3.4 g of tris(dibenzylideneacetone)dipalladium(0) (4 mmol), 3 mL of tri-t-butylphosphine (7 mmol, 50% toluene solution), 17.8 g of sodium t-butoxide (186 mmol), and 600 mL of toluene were introduced into a reaction vessel, and the mixture was refluxed for 3 hours. The reaction solution was cooled to room temperature. The solvent was removed with a rotary evaporator, and the resulting product was purified by column chromatography to obtain 37.8 g of compound C-5 (yield: 51%). The properties of compound C-5 are shown in Table 1.

EXAMPLE 3: PREPARATION OF COMPOUND C-7

(16) ##STR00144##

(17) 10 g of compound 1-4 (31 mmol), 16.5 g of N-1,1-biphenyl-4-yl-9,9-dimethyl-9H-fluorene-2-amine (34 mmol), 1.4 g of tris(dibenzylideneacetone)dipalladium(0) (2 mmol), 1.2 mL of tri-t-butylphosphine (3 mmol, 50% toluene solution), 5.9 g of sodium t-butoxide (62 mmol), and 600 mL of toluene were introduced into a reaction vessel, and the mixture was refluxed for 3 hours. The reaction solution was cooled to room temperature. The solvent was removed with a rotary evaporator, and the resulting product was purified by column chromatography to obtain 11 g of compound C-7 (yield: 49%). The properties of compound C-7 are shown in Table 1.

EXAMPLE 4: PREPARATION OF COMPOUND C-73

(18) ##STR00145##

(19) Preparation of Compound 2-1

(20) 10 g of 2-bromo-11,11-dimethyl-11H-benzo[b]fluorene (31 mmol), 10 mL of dimethylformamide, and 7.2 g of N-bromosuccinimide (40 mmol) were introduced into a reaction vessel, and the mixture was stirred at room temperature overnight. The reaction solution was diluted with ethylacetate and washed with distilled water. The extracted organic layer was then dried with magnesium sulfate. The solvent was removed with a rotary evaporator, and the separated solid was filtered and washed with cold methyl alcohol to obtain 10.5 mg of compound 2-1 (yield: 84%).

(21) Preparation of Compound C-73

(22) 10 g of compound 2-1 (25 mmol), 15.6 g of N-1,1-biphenyl-4-yl-9,9-diphenyl-9H-fluorene-2-amine (55 mmol), 2.3 g of tris(dibenzylideneacetone)dipalladium(0) (2.5 mmol), 2 mL of tri-t-butylphosphine (5 mmol, 50% toluene solution), 9.6 g of sodium t-butoxide (99 mmol), and 240 mL of toluene were introduced into a reaction vessel, and the mixture was refluxed for 3 hours. The reaction solution was cooled to room temperature. The solvent was removed with a rotary evaporator, and the resulting product was purified by column chromatography to obtain 9.6 g of compound C-73 (yield: 47%). The properties of compound C-73 are shown in Table 1.

EXAMPLE 5: PREPARATION OF COMPOUND C-10

(23) ##STR00146##

(24) 7.4 g of compound 1-4 (23 mmol), 9.4 g of 9,9-dimethyl-N-(4-(naphthalen-2-yl)phenyl)-9H-fluorene-2-amine (23 mmol), 1.05 g of tris(dibenzylideneacetone)dipalladium(0) (1.15 mmol), 1.2 mL of tri-t-butylphosphine (2.3 mmol, 50% toluene solution), 4.4 g of sodium t-butoxide (46 mmol), and 200 mL of toluene were introduced into a reaction vessel, and the mixture was refluxed for 3 hours at 80 C. The reaction solution was cooled to room temperature. The solvent was removed with a rotary evaporator, and the resulting product was purified by column chromatography to obtain 3.7 g of compound C-10 (yield: 25%). The properties of compound C-10 are shown in Table 1.

EXAMPLE 6: PREPARATION OF COMPOUND C-91

(25) ##STR00147##

(26) 10 g of compound 1-4 (31 mmol), 14.0 g of N-(9,9-dimethyl-9H-fluoren-2-yl)-11,11-dimethyl-11H-benzo[b]fluorene-2-amine (31 mmol), 1.42 g of tris(dibenzylideneacetone)dipalladium(0) (1.60 mmol), 1.6 mL of tri-t-butylphosphine (3.1 mmol, 50% toluene solution), 5.9 g of sodium t-butoxide (62 mmol), and 155 mL of toluene were introduced into a reaction vessel, and the mixture was refluxed for 16 hours at 80 C. The reaction solution was cooled to room temperature. The solvent was removed with a rotary evaporator, and the resulting product was purified by column chromatography to obtain 9.1 g of compound C-91 (yield: 42%). The properties of compound C-91 are shown in Table 1.

EXAMPLE 7: PREPARATION OF COMPOUND C-92

(27) ##STR00148##

(28) 8 g of compound 1-4 (25 mmol), 11.9 g of N-([1,1:4,1-terphenyl]-4-yl)-9,9-dimethyl-9H-fluorene-2-amine (27 mmol), 1.13 g of tris(dibenzylideneacetone)dipalladium(0) (1.35 mmol), 1.0 mL of tri-t-butylphosphine (2.7 mmol, 50% toluene solution), 4.8 g of sodium t-butoxide (50 mmol), and 125 mL of toluene were introduced into a reaction vessel, and the mixture was refluxed for 3 hours at 80 C. The reaction solution was cooled to room temperature. The solvent was removed with a rotary evaporator, and the resulting product was purified by column chromatography to obtain 5.7 g of compound C-92 (yield: 34%). The properties of compound C-92 are shown in Table 1.

EXAMPLE 8: PREPARATION OF COMPOUND C-71

(29) ##STR00149##

(30) 10 g of compound 2-1 (25 mmol), 13.4 g of N-phenyl-[1,1-biphenyl]-4-amine (55 mmol), 2.3 g of tris(dibenzylideneacetone)dipalladium(0) (2.5 mmol), 2 mL of tri-t-butylphosphine (5 mmol, 50% toluene solution), 9.6 g of sodium t-butoxide (99 mmol), and 260 mL of toluene were introduced into a reaction vessel, and the mixture was refluxed for 3 hours at 80 C. The reaction solution was cooled to room temperature. The solvent was removed with a rotary evaporator, and the resulting product was purified by column chromatography to obtain 5.2 g of compound C-71 (yield: 18%). The properties of compound C-71 are shown in Table 1.

EXAMPLE 9: PREPARATION OF COMPOUND C-93

(31) ##STR00150##

(32) Preparation of Compound 3-1

(33) 15 g of N-(9,9-dimethyl-9H-fluoren-2-yl)-11,11-dimethyl-N-(4-(naphthalen-2-yl)phenyl)-1H-benzo[b]fluorene-2-amine (23 mmol), 120 mL of dimethylformamide, and 5.3 g of N-bromosuccinimide (30 mmol) were introduced into a reaction vessel, and the mixture was stirred at room temperature overnight. The reaction solution was diluted with ethylacetate and washed with distilled water. The extracted organic layer was then dried with magnesium sulfate. The solvent was removed with a rotary evaporator, and the resulting product was purified by column chromatography to obtain 15 g of compound 3-1 (yield: 89%).

(34) Preparation of Compound C-93

(35) 10 g of compound 3-1 (14 mmol), 2.7 g of diphenylamine (16 mmol), 0.63 g of tris(dibenzylideneacetone)dipalladium(0) (0.68 mmol), 0.5 mL of tri-t-butylphosphine (1.4 mmol, 50% toluene solution), 2.6 g of sodium t-butoxide (28 mmol), and 260 mL of toluene were introduced into a reaction vessel, and the mixture was refluxed for 3 hours at 80 C. The reaction solution was cooled to room temperature. The solvent was removed with a rotary evaporator, and the resulting product was purified by column chromatography to obtain 3.1 g of compound C-93 (yield: 18%). The properties of compound C-93 are shown in Table 1.

EXAMPLE 10: PREPARATION OF COMPOUND C-94

(36) ##STR00151##

(37) Preparation of Compound 4-1

(38) 26 g of 2-([1,1-biphenyl]-4-yl)-11,11-dimethyl-11H-benzo[b]fluorene (66 mmol), 330 mL of dimethylformamide, 200 mL of methylene chloride, and 15.2 g of N-bromosuccinimide (85 mmol) were introduced into a reaction vessel, and the mixture was stirred at room temperature overnight. The reaction solution was diluted with ethylacetate and washed with distilled water. The extracted organic layer was then dried with magnesium sulfate. The solvent was removed with a rotary evaporator, and the resulting product was purified by column chromatography to obtain 26 g of compound 4-1 (yield: 83%).

(39) Preparation of Compound C-94

(40) 13 g of compound 4-1 (27 mmol), 9.9 g of N-1,1-biphenyl-4-yl-9,9-dimethyl-9H-fluorene-2-amine (27 mmol), 1.25 g of tris(dibenzylideneacetone)dipalladium(0) (1.4 mmol), 1.1 mL of tri-t-butylphosphine (2.7 mmol, 50% toluene solution), 5.3 g of sodium t-butoxide (54 mmol), and 136 mL of toluene were introduced into a reaction vessel, and the mixture was refluxed for 3 hours at 80 C. The reaction solution was cooled to room temperature. The solvent was removed with a rotary evaporator, and the resulting product was purified by column chromatography to obtain 4.5 g of compound C-94 (yield: 22%). The properties of compound C-94 are shown in Table 1.

EXAMPLE 11: PREPARATION OF COMPOUND C-25

(41) ##STR00152##

(42) 4 g of compound 1-4 (12 mmol), 7.9 g of N-([1,1-biphenyl]-4-yl)-9,9-dimethyl-N-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-[1,1-biphenyl]-4-yl)-9H-fluorene-2-amine (12 mmol), 0.72 g of tetrakis(triphenylphosphine)palladium (0.6 mmol), 3.4 g of potassium carbonate (24 mmol), 30 mL of toluene, and 15 mL of ethyl alcohol were introduced into a reaction vessel, 15 mL of distilled water was added thereto, and the mixture was stirred at 80 C. for 18 hours. After completion of the reaction, ethyl alcohol and toluene were removed with a rotary evaporator, and an organic layer was extracted with methylene chloride and distilled water. The organic layer was then dried with magnesium sulfate. The solvent was removed with a rotary evaporator, and the resulting product was purified by column chromatography to obtain 3.1 g of compound C-25 (yield: 33%). The properties of compound C-25 are shown in Table 1.

(43) TABLE-US-00001 TABLE 1 MS/EIMS Yield UV PL M.P. (M + H) Compound (%) (nm) (nm) ( C.) Found Calculated C-4 52 422 481 222 644.2 644.3 C-5 51 384 473 250 604.2 604.3 C-7 49 418 447 251 728.2 728.3 C-73 47 418 445 286 811.3 811.4 C-10 25 410 473 165 654.2 654.3 C-91 42 418 479 173.5 694.2 694.4 C-92 34 394 449 258 680.2 680.3 C-71 18 420 443 167 731.2 731.3 C-93 28 415 461 295 821.2 821.4 C-94 22 378 489 184 756.2 756.4 C-25 33 392 459 179 756.2 756.4

DEVICE EXAMPLE 1: PRODUCTION OF AN OLED DEVICE COMPRISING THE ORGANIC ELECTROLUMINESCENT COMPOUND OF THE PRESENT DISCLOSURE

(44) An OLED device comprising the organic electroluminescent compound of the present disclosure was produced as follows. A transparent electrode indium tin oxide (ITO) thin film (10 /sq) on a glass substrate for an organic light-emitting diode (OLED) device (Geomatec, Japan) was subjected to an ultrasonic washing with acetone, ethanol, and distilled water, sequentially, and was then stored in isopropanol. Next, the ITO substrate was mounted on a substrate holder of a vacuum vapor depositing apparatus. N.sup.4,N.sup.4-diphenyl-N.sup.4,N.sup.4-bis(9-phenyl-9H-carbazol-3-yl)-[1,1-biphenyl]-4,4-diamine (compound HI-1) was introduced into a cell of said vacuum vapor depositing apparatus, and then the pressure in the chamber of said apparatus was controlled to 10.sup.6 torr. Thereafter, an electric current was applied to the cell to evaporate the above-introduced material, thereby forming a first hole injection layer having a thickness of 90 nm on the ITO substrate. 1,4,5,8,9,12-hexaazatriphenylene-hexacarbonitrile (compound HI-2) was then introduced into another cell of said vacuum vapor depositing apparatus, and was evaporated by applying an electric current to the cell, thereby forming a second hole injection layer having a thickness of 5 nm on the first hole injection layer. N-([1,1-biphenyl]-4-yl)-9,9-dimethyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluorene-2-amine (compound HT-1) was introduced into another cell of said vacuum vapor depositing apparatus, and was evaporated by applying an electric current to the cell, thereby forming a first hole transport layer having a thickness of 10 nm on the second hole injection layer. Compound C-4 was introduced into another cell of said vacuum vapor depositing apparatus, and was evaporated by applying an electric current to the cell, thereby forming a second hole transport layer having a thickness of 60 nm on the first hole transport layer. After forming the hole injection layers and the hole transport layers, a light-emitting layer was then deposited as follows. Compound B-198 as below was introduced into one cell of the vacuum vapor depositing apparatus as a host, and compound D-71 was introduced into another cell as a dopant. The two materials were evaporated at different rates and were deposited in a doping amount of 2 wt % (the amount of dopant) based on the total amount of the dopant and host to form a light-emitting layer having a thickness of 40 nm on the second hole transport layer. 2,4-bis(9,9-dimethyl-9H-fluoren-2-yl)-6-(naphthalen-2-yl)-1,3,5-triazine (compound ET-1) and lithium quinolate (compound EI-1) were then introduced into another two cells, evaporated at the rate of 1:1, and deposited to form an electron transport layer having a thickness of 35 nm on the light-emitting layer. Next, after depositing lithium quinolate (compound EI-1) as an electron injection layer having a thickness of 2 nm on the electron transport layer, an Al cathode having a thickness of 80 nm was deposited by another vacuum vapor deposition apparatus on the electron injection layer. Thus, an OLED device was produced.

(45) The driving voltage, luminous efficiency, and CIE color coordinates at a luminance of 1,000 nit of the produced OLED device are provided in Table 2 below.

DEVICE EXAMPLES 2 AND 3: PRODUCTION OF AN OLED DEVICE COMPRISING THE ORGANIC ELECTROLUMINESCENT COMPOUND OF THE PRESENT DISCLOSURE

(46) OLED devices were produced in the same manner as in Device Example 1, except for using the compounds shown in Table 2 for the second hole transport layer.

(47) The driving voltage, luminous efficiency, and CIE color coordinates at a luminance of 1,000 nit of the produced OLED devices are provided in Table 2 below.

COMPARATIVE EXAMPLES 1 TO 3: PRODUCTION OF AN OLED DEVICE COMPRISING A CONVENTIONAL ORGANIC ELECTROLUMINESCENT COMPOUND

(48) OLED devices were produced in the same manner as in Device Example 1, except for using the compounds shown in Table 2 for the second hole transport layer.

(49) The driving voltage, luminous efficiency, and CIE color coordinates at a luminance of 1,000 nit of the produced OLED devices are provided in Table 2 below.

(50) TABLE-US-00002 TABLE 2 Second hole Color Color transport Voltage Efficiency coordinate coordinate layer (V) (cd/A) (x) (y) Device C-4 2.8 19.0 0.670 0.329 Example 1 Device C-5 2.7 24.7 0.671 0.329 Example 2 Device C-7 2.7 26.2 0.671 0.328 Example 3 Comparative R-1 2.9 12.2 0.667 0.331 Example 1 Comparative R-2 2.8 15.2 0.669 0.329 Example 2 Comparative R-3 2.9 15.8 0.670 0.329 Example 3

DEVICE EXAMPLES 4 TO 11: PRODUCTION OF AN OLED DEVICE COMPRISING THE ORGANIC ELECTROLUMINESCENT COMPOUND OF THE PRESENT DISCLOSURE

(51) OLED devices were produced in the same manner as in Device Example 1, except for using the compounds shown in Table 3 for the second hole transport layer, and using compound B-199 for the host.

(52) The driving voltage, luminous efficiency, and CIE color coordinates at a luminance of 1,000 nit of the produced OLED devices are provided in Table 3 below.

COMPARATIVE EXAMPLES 4 AND 5: PRODUCTION OF AN OLED DEVICE COMPRISING A CONVENTIONAL ORGANIC ELECTROLUMINESCENT COMPOUND

(53) OLED devices were produced in the same manner as in Device Example 4, except for using the compounds shown in Table 3 for the second hole transport layer.

(54) The driving voltage, luminous efficiency, and CIE color coordinates at a luminance of 1,000 nit of the produced OLED devices are provided in Table 3 below.

(55) TABLE-US-00003 TABLE 3 Second hole Color Color transport Voltage Efficiency coordinate coordinate layer (V) (cd/A) (x) (y) Device C-8 2.7 25.1 0.667 0.332 Example 4 Device C-91 2.8 20.4 0.666 0.332 Example 5 Device C-92 2.8 23.7 0.669 0.331 Example 6 Device C-73 2.8 19.7 0.666 0.333 Example 7 Device C-71 2.8 20.6 0.668 0.331 Example 8 Device C-93 3.2 18.6 0.666 0.333 Example 9 Device C-94 2.9 26.0 0.669 0.331 Example 10 Device C-25 2.9 24.4 0.669 0.331 Example 11 Comparative R-1 3.0 14.3 0.663 0.334 Example 4 Comparative R-3 3.0 16.3 0.667 0.332 Example 5

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(57) As shown in Tables 2 and 3, the devices using the organic electroluminescent compound according to the present disclosure in a second hole transport layer have excellent luminous efficiency. The second hole transport layer can also function as a hole auxiliary layer or a light-emitting auxiliary layer.

(58) From the results, it can be seen that the characteristics of the device are varied depending on the substituent's position, i.e. whether it is bonded at the second carbon position or the fifth carbon position, of a benzo[b]fluorene structure even when the substituents are the same.

(59) In addition, upon comparing Device Examples 1 to 3 and Comparative Examples 1 to 3, using compounds of structural isomer relation, the organic electroluminescent compound according to the present disclosure has a benzo[b]fluorene structure in which the substituent is bonded at the fifth carbon position. Accordingly, the luminous efficiency of the device increases due to the increase of triplet energy, and the thermal stability of the device is excellent due to the decrease of deposition temperature even when the molecular weight of the compounds are the same. This can be verified from Table 4 below.

(60) TABLE-US-00004 TABLE 4 Band Triplet Deposition HOMO LUMO gap energy temperature (eV) (eV) (eV) (eV) ( C.) Device C-4 1.393 4.742 3.349 2.378 250 Example 1 Device C-5 1.397 4.831 3.434 2.400 250 Example 2 Device C-7 1.365 4.836 3.471 2.403 290 Example 3 Device C-8 1.412 4.826 3.415 2.398 280 Example 4 Device C-91 1.421 4.763 3.342 2.371 285 Example 5 Device C-92 1.411 4.828 3.417 2.397 290 Example 6 Device C-73 1.362 4.721 3.359 2.289 316 Example 7 Device C-71 1.377 4.803 3.426 2.310 315 Example 8 Device C-93 1.385 4.741 3.356 2.296 328 Example 9 Device C-94 1.556 4.836 3.279 2.324 225 Example 10 Device C-25 1.175 4.826 3.651 2.520 360 Example 11 Comparative R-1 1.232 4.687 3.455 2.363 310 Example 1 Comparative R-2 1.242 4.752 3.510 2.377 280 Example 2 Comparative R-3 1.245 4.767 3.522 2.381 335 Example 3