ORGANOELECTROLUMINESCENT DEVICE USING POLYCYCLIC AROMATIC COMPOUNDS

Abstract

An organoelectroluminescent device according to the present invention employs compounds of characteristic structures as a hole transport material and a dopant material in a hole injection layer or a hole transport layer, and in an emissive layer, respectively, and thus can be driven at a low voltage and realize highly efficient emission characteristics with excellent external quantum efficiency. Thus, the organoelectroluminescent device may be industrially advantageously used in a flexible display device, a flexible display device, a single-color or white-color flat lighting device, a single-color or shite-color flexible lighting device, and the like.

Claims

1. An organic light-emitting device comprising: a first electrode; a second electrode facing the first electrode; and a hole injection layer or a hole transport layer and a light-emitting layer interposed between the first electrode and the second electrode, wherein (i) the hole injection layer or the hole transport layer comprises at least one compound represented by the following [Formula A], and (ii) the light-emitting layer comprises a compound represented by any one of the following [Formula B] to [Formula D]: ##STR00198## wherein L is a single bond, a substituted or unsubstituted aromatic C6-C50 hydrocarbon ring, or a substituted or unsubstituted C2-050 aromatic heterocyclic ring; n is an integer of 1 to 3, with the proviso that when n is 2 or more, L's are identical to or different from each other; Ar is selected from a substituted or unsubstituted C5-C50 aryl group and a substituted or unsubstituted C2-C50 heteroaryl group; R.sub.a to R.sub.c are identical to or different from each other, and are each independently hydrogen, deuterium, a substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C6-C50 aryl group, a substituted or unsubstituted C3-C30 cycloalkyl group, a substituted or unsubstituted C2-C50 heteroaryl group, a substituted or unsubstituted C1-C30 alkoxy group, a substituted or unsubstituted C6-C30 aryloxy group, a substituted or unsubstituted C1-C30 alkylthioxy group, a substituted or unsubstituted C5-C30 arylthioxy group, a substituted or unsubstituted C1-C30 alkylamine group, a substituted or unsubstituted C5-C30 arylamine group, a substituted or unsubstituted C1-C30 alkylsilyl group, a substituted or unsubstituted C5-C30 arylsilyl group, a nitro group, a cyano group, and a halogen group, with the proviso that R.sub.b and R.sub.a are bonded to each other to further form an alicyclic or aromatic monocyclic or polycyclic ring, ##STR00199## wherein Q.sub.1 to Q.sub.3 are identical to or different from each other, and are each independently a substituted or unsubstituted aromatic C6-C50 hydrocarbon ring, or a substituted or unsubstituted C2-050 aromatic heterocyclic group, Y is selected from N—R.sub.1, CR.sub.2R.sub.3, O, S, Se, and SiR.sub.4R.sub.5, with the proviso that Y's are identical to or different from each other, X is selected from B, P and P═O, R.sub.1 to R.sub.5 are identical to or different from each other, and are each independently hydrogen, deuterium, a substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C6-C50 aryl group, a substituted or unsubstituted C3-C30 cycloalkyl group, a substituted or unsubstituted C2-C50 heteroaryl group, a substituted or unsubstituted C1-C30 alkoxy group, a substituted or unsubstituted C6-C30 aryloxy group, a substituted or unsubstituted C1-C30 alkylthioxy group, a substituted or unsubstituted C5-C30 arylthioxy group, a substituted or unsubstituted C1-C30 alkylamine group, a substituted or unsubstituted C5-C30 arylamine group, a substituted or unsubstituted C1-C30 alkylsilyl group, a substituted or unsubstituted C5-C30 arylsilyl group, a nitro group, a cyano group, and a halogen group, with the proviso that each of R.sub.1 to R.sub.5 is bonded to the ring Q.sub.1 to Q.sub.3 to further form an alicyclic or aromatic monocyclic or polycyclic ring, and R.sub.2 and R.sub.3, and R.sub.4 and R.sub.5 are bonded to each other to further form an alicyclic or aromatic monocyclic or polycyclic ring, Cy1 is linked to an adjacent nitrogen (N) atom and an aromatic carbon atom in the adjacent Q.sub.1 ring to form a fused ring including a nitrogen (N) atom, an aromatic carbon atom in the Q.sub.1 ring to which the nitrogen (N) atom is bonded, and an aromatic carbon atom in the Q.sub.1 ring to which Cy1 is bonded, with the proviso that the fused ring formed by Cy1 is a substituted or unsubstituted C2-C5 alkylene group, provided that the nitrogen (N) atom, the aromatic carbon atom in the Q.sub.1 ring to which the nitrogen (N) atom is bonded, and the aromatic carbon atom in the Q.sub.1 ring to which Cy1 is bonded are excluded, Cy2 is added to Cy1 to form a saturated hydrocarbon ring, with the proviso that the ring formed by Cy2 is a substituted or unsubstituted C2-C5 alkylene group, provided that the carbon atom included in Cy1 is excluded, and Cy3 is linked to a carbon atom bonded to a nitrogen atom in the adjacent Cy1, and an aromatic carbon atom in the Q.sub.3 ring to form a fused ring including the aromatic carbon atom in the Q.sub.3 ring to which Cy3 is bonded, the nitrogen (N) atom and the carbon atom in Cy1 bonded to the nitrogen (N) atom, with the proviso that the fused ring formed by Cy3 is a substituted or unsubstituted C1-C4 alkylene group, provided that the aromatic carbon atom in the Q.sub.3 ring to which Cy3 is bonded, the nitrogen (N) atom and the carbon atom in Cy1 bonded to the nitrogen (N) atom are excluded.

2. The organic light-emitting device according to claim 1, wherein L in [Formula A] is a single bond, or a substituted or unsubstituted aromatic C6-C50 hydrocarbon ring.

3. The organic light-emitting device according to claim 2, wherein L in [Formula A] is a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted phenanthryl group, or a substituted or unsubstituted fluorenyl group.

4. The organic light-emitting device according to claim 1, wherein Y in [Formula B] to [Formula D] is NR.sub.1.

5. The organic light-emitting device according to claim 1, wherein the compound represented by [Formula A] is selected from the compounds represented by the following formulas: ##STR00200## ##STR00201## ##STR00202## ##STR00203## ##STR00204## ##STR00205## ##STR00206## ##STR00207## ##STR00208## ##STR00209## ##STR00210## ##STR00211## ##STR00212## ##STR00213## ##STR00214## ##STR00215## ##STR00216## ##STR00217## ##STR00218## ##STR00219## ##STR00220## ##STR00221## ##STR00222## ##STR00223## ##STR00224## ##STR00225## ##STR00226## ##STR00227## ##STR00228## ##STR00229## ##STR00230## ##STR00231## ##STR00232## ##STR00233## ##STR00234## ##STR00235## ##STR00236## ##STR00237## ##STR00238## ##STR00239## ##STR00240## ##STR00241## ##STR00242## ##STR00243## ##STR00244## ##STR00245## ##STR00246## ##STR00247## ##STR00248## ##STR00249## ##STR00250## ##STR00251## ##STR00252## ##STR00253## ##STR00254## ##STR00255## ##STR00256## ##STR00257## ##STR00258## ##STR00259## ##STR00260## ##STR00261## ##STR00262## ##STR00263## ##STR00264## ##STR00265## ##STR00266##

6. The organic light-emitting device according to claim 1, wherein the compounds represented by [Formula B] to [Formula D] are selected from compounds represented by the following formulas: ##STR00267## ##STR00268## ##STR00269## ##STR00270## ##STR00271## ##STR00272## ##STR00273## ##STR00274## ##STR00275## ##STR00276## ##STR00277## ##STR00278## ##STR00279## ##STR00280## ##STR00281## ##STR00282## ##STR00283## ##STR00284## ##STR00285## ##STR00286## ##STR00287## ##STR00288## ##STR00289## ##STR00290## ##STR00291## ##STR00292## ##STR00293## ##STR00294## ##STR00295## ##STR00296## ##STR00297## ##STR00298## ##STR00299## ##STR00300##

7. The organic light-emitting device according to claim 1, further comprising at least one selected from an electron injection layer, an electron transport layer, an electron blocking layer, a hole blocking layer and a hole auxiliary layer, in addition to the hole injection layer, the hole transport layer and the light emitting layer, between the first electrode and the second electrode.

8. The organic light-emitting device according to claim 7, wherein at least one selected from the layers is formed by a deposition process or a solution process.

9. The organic light-emitting device according to claim 1, wherein the organic light-emitting device is used for a display or lighting system selected from flat panel displays, flexible displays, monochromatic or white flat panel lighting systems, monochromatic or white flexible lighting systems, vehicle displays, and displays for virtual or augmented reality.

Description

MODE FOR INVENTION

[0070] Hereinafter, the present invention will be described in more detail with reference to preferred examples. However, it will be obvious to those skilled in the art that these examples are merely provided for illustration of the present invention, and should not be construed as limiting the scope of the present invention.

[Formula B] to [Formula D] Synthesis Example

Synthesis Example 1. Synthesis of Formula 1

Synthesis Example 1-1. Synthesis of <Intermediate 1-a

[0071] ##STR00185##

[0072] 100 g (0.924 mol) of phenylhydrazine and 500 mL of acetic acid were stirred in a round-bottom flask and then heated to 60° C. 103.6 g (0.924 mol) of 2-methyl cyclohexanone was slowly added dropwise, followed by refluxing for 8 hours. After completion of the reaction, the reaction product was extracted with water and ethyl acetate, concentrated and separated by column chromatography to obtain 130 g of <Intermediate 1-a>. (yield 76%)

Synthesis Example 1-2. Synthesis of <Intermediate 1-b>

[0073] ##STR00186##

[0074] 75 g (405 mmol) of <Intermediate 1-a> was added to a round-bottom flask containing 750 mL of toluene under a nitrogen atmosphere, cooled to −10° C., and then 380 mL (608 mmol) of 1.6 M methyl lithium was slowly added dropwise, followed by stirring at −10° C. for about 3 hours. After completion of the reaction, the product was extracted with water and ethyl acetate, concentrated and separated by column chromatography to obtain 50.5 g of <Intermediate 1-b>. (yield 62%)

Synthesis Example 1-3. Synthesis of <Intermediate 1-c>

[0075] ##STR00187##

[0076] 50 g (251 mmol) of <intermediate 1-b>, 56.7 g (251 mmol) of 1-bromo-2,3-dichlorobenzene, 4.5 g (5 mmol) of tris(dibenzylideneacetone)dipalladium, 2 g (10 mmol) of tritertiary butylphosphine, 35.8 g (373 mmol) of sodium tertiary butoxide, and 500 mL of toluene were added to a round-bottom flask under a nitrogen atmosphere, followed by refluxing for 24 hours. After completion of the reaction, the organic layer was concentrated under reduced pressure and separated by column chromatography to obtain 35.6 g of <Intermediate 1-c>. (yield 41%)

Synthesis Example 1-4. Synthesis of <Intermediate 1-d>

[0077] ##STR00188##

[0078] <Intermediate 1-d> was obtained in the same manner as in Synthesis Example 1-3, except that diphenylamine was used instead of <Intermediate 1-b> and <Intermediate 1-c> was used instead of 1-bromo-2,3-dichlorobenzene in Synthesis Example 1-3. (yield 73%)

Synthesis Example 1-5. Synthesis of <Compound 1>

[0079] ##STR00189##

[0080] 20 g (42 mmol) of <Intermediate 1-d> was added to a round-bottom flask containing 200 mL of tert-butylbenzene under a nitrogen atmosphere, cooled to −30° C., and 49.1 mL (84 mmol) of a 1.7 M tert-butyllithium pentane solution was slowly added dropwise. After completion of the dropwise addition, the temperature was raised to 60° C., followed by stirring for 3 hours and removal of pentane through distillation. The residue was cooled to −50° C., 20.8 g (84 mmol) of boron tribromide was added dropwise thereto, and the mixture was warmed to room temperature, followed by stirring for 1 hour. The reaction product was cooled to 0° C. again, and 10.7 g (84 mmol) of N,N-diisopropylethylamine was added thereto, followed by stirring at 120° C. for 3 hours. After completion of the reaction, tert-butylbenzene was removed by distillation under reduced pressure, extracted with water and ethyl acetate, and concentrated by column chromatography to obtain 5.3 g of <Compound 1>. (yield 28%)

[0081] MS (MALDI-TOF): m/z 452.24 [M.sup.−]

Synthesis Example 2. Synthesis of Compound 33

Synthesis Example 2-1. Synthesis of <Intermediate 2-a>

[0082] ##STR00190##

[0083] <Intermediate 2-a> was obtained in the same manner as in Synthesis Example 1-3, except that 2,3-dimethyl-2,3-dihydro-1H-indole was used instead of <Intermediate 1-b> in Synthesis Example 1-3. (yield 52%)

Synthesis Example 2-2. Synthesis of <Intermediate 2-b>

[0084] ##STR00191##

[0085] <Intermediate 2-b> was obtained in the same manner as in Synthesis Example 1-3, except that N.sup.1,N.sup.2,N.sup.3-triphenylbenzene-1,3,-diamine was used instead of <Intermediate 1-b> and <Intermediate 2-a> was used instead of 1-bromo-2,3-dichlorobenzene. (yield 55%)

Synthesis Example 2-3. Synthesis of <Formula 33>

[0086] ##STR00192##

[0087] <Formula 33> was obtained in the same manner as in Synthesis Example 1-5, except that <Intermediate 2-b> was used instead of <Intermediate 1-d>. (yield 68%)

Synthesis Example 3. Synthesis of Formula 95

Synthesis Example 3-1. Synthesis of <Formula 95>

[0088] <Formula 95> was obtained in the same manner as in Synthesis Example 1-4, except that N.sup.1,N.sup.2,N.sup.3-triphenyl-1,3-benzenediamine was used instead of diphenylamine. (yield 17%)

[0089] MS(MALDI-TOF): m/z 619.32 [M.sup.+]

[Formula A] Synthesis Example>

Synthesis Example 11. Synthesis of Compound 12

Synthesis Example 11-1. Synthesis of <Intermediate 11-a

[0090] ##STR00193##

[0091] 3-bromo-9-phenyl-9H-carbazole (11.3 g, 0.035 mol), 4-aminobiphenyl (6.6 g, 0.039 mol), tris(dibenzylideneacetone)dipalladium (0) (0.65 g, 0.0007 mol), sodium tert-butoxide (6.79 g, 0.0706 mol), 2,2′-bis(diphenylphosphino)-1,1′-binaphthalene (0.44 g, 0.0007 mol) and 100 mL of toluene were added to a round-bottom flask, followed by stirring under reflux for 3 hours. After completion of the reaction, the mixture was cooled to room temperature and extracted with ethyl acetate and water. The organic layer was separated, dehydrated with magnesium sulfate, and then concentrated under reduced pressure. The result was separated by column chromatography to obtain 12.2 g of <Intermediate 11-a>. (yield 85%)

Synthesis Example 11-2. Synthesis of <Compound 12>

[0092] ##STR00194##

[0093] 3-bromo-9,9-dimethylfluorene (2.4 g, 0.009 mol), <Intermediate 11-a> (5.3 g, 0.013 mol), palladium (II) acetate (0.08 g, 0.4 mmol), sodium tert-butoxide (3.4 g, 0.035 mol), tri-tert-butylphosphine (0.07 g, 0.4 mmol), and 60 mL of toluene were added to a round-bottom flask, followed by stirring under reflux for 2 hours. After completion of the reaction, the reaction solution was cooled to room temperature and extracted with ethyl acetate and water. The organic layer was separated, dehydrated with magnesium sulfate, and then concentrated under reduced pressure. The result was separated and purified by column chromatography and recrystallized with dichloromethane and acetone to obtain 2.6 g of <Compound 12>. (yield 48%)

[0094] MS (MALDI-TOF): m/z 602.27 [M.sup.−]

Synthesis Example 12. Synthesis of Compound 30

Synthesis Example 12-(1): Synthesis of Compound 30

[0095] <Compound 30> was synthesized in the same manner as in Synthesis Example 11 except that 1-naphthylamine was used instead of 4-aminobiphenyl used in Synthesis Example 11-(1), and 3-bromo-9,9-dimethylfluorene was used instead of 2-bromo-9,9-dimethylfluorene used in Synthesis Example 11-(2) (yield 45%).

[0096] MS (MALDI-TOF): m/z 830.29 [M.sup.−]

Synthesis Example 13. Synthesis of Compound 44

Synthesis Example 13-(1): Synthesis of Compound 44

[0097] <Compound 44> was synthesized in the same manner as in Synthesis Example 11 except that aniline-2,3,4,5,6-d5 was used instead of 4-aminobiphenyl used in Synthesis Example 11-(1), and 2-bromo-9,9′-dimethylfluorene was used instead of 2-bromo-9,9-dimethylfluorene used in Synthesis Example 11-(2) (yield 46%).

[0098] MS (MALDI-TOF): m/z 653.29 [M.sup.+]

Synthesis Example 14. Synthesis of Compound 78

Synthesis Example 14-(1): Synthesis of Compound 78

[0099] <Compound 78> was synthesized in the same manner as in Synthesis Example 11 except that 2-bromo-9,9-diphenylfluorene was used instead of 2-bromo-9,9-dimethylfluorene used in Synthesis Example 11-(2) (yield 46%).

[0100] MS (MALDI-TOF): m/z 726.30 [M.sup.+]

Synthesis Example 15. Synthesis of Compound 102

Synthesis Example 15-(1): Synthesis of Compound 102

[0101] <Compound 102> was synthesized in the same manner as in Synthesis Example 11, except that 2-naphthylamine was used instead of 4-aminobiphenyl used in Synthesis Example 11-(1) and 2-(4-bromophenyl)-9,9-diphenyl-9H-fluorene was used instead of 2-bromo-9,9-dimethylfluorene used in Synthesis Example 11-(2) (yield 45%).

[0102] MS (MALDI-TOF): m/z 776.32 [M.sup.+]

Synthesis Example 16. Synthesis of Compound 174

Synthesis Example 16-(1): Synthesis of Compound 174

[0103] <Compound 174> was synthesized in the same manner as in Synthesis Example 11, except that 3-bromo-9-phenyl-9H-carbazole was used instead of 2-bromo-9-phenyl-9H-carbazole used in Synthesis Example 11-(1), and 4-(1-naphthyl)aniline was used instead of 4-aminobiphenyl (yield 47%).

[0104] MS (MALDI-TOF): m/z 652.29 [M.sup.+]

Synthesis Example 17. Synthesis of Compound 195

Synthesis Example 17-(1): Synthesis of Compound 195

[0105] <Compound 195> was synthesized in the same manner as in Synthesis Example 11, except that 3-bromo-9-phenyl-9H-carbazole was used instead of 2-bromo-9-phenyl-9H-carbazole used in Synthesis Example 11-(1), 3-aminobiphenyl was used instead of 4-aminobiphenyl, and 1-(4-bromophenyl)-9,9-dimethyl-9H-fluorene was used instead of 2-bromo-9,9-dimethylfluorene used in Synthesis Example 11-(2) (yield 45%).

[0106] MS (MALDI-TOF): m/z 678.30 [M.sup.+]

Examples 1 to 15: Fabrication of Organic Light-Emitting Devices

[0107] ITO glass was patterned such that a light-emitting area of the ITO glass was adjusted to 2 mm×2 mm and was then washed. The ITO glass was mounted in a vacuum chamber, a base pressure was set to 1×10.sup.−7 torr, and 2-TNATA (400 Å) and a material for a hole transport layer shown in [Table 1] (200 Å) were sequentially deposited on the ITO glass. Then, a mixture of [BH] as a host and the compound shown in the following Table 1 as a dopant (3 wt %) was deposited to a thickness of 250 Å to form a light-emitting layer. Then, a compound of [Formula E-1] was deposited thereon to a thickness of 300 Å to form an electron transport layer, Liq was deposited thereon to a thickness of 10 Å to form an electron injection layer, and Al was deposited thereon to a thickness of 1,000 Å to form a cathode. As a result, an organic light-emitting device was fabricated. The properties of the organic light-emitting device were measured at 10 mA/cm.sup.2.

##STR00195##

Comparative Examples 1 to 8

[0108] Organic light-emitting devices were fabricated in the same manner as in Examples above, except that [HT] and [BD1] were used instead of the compound used as the hole transport layer material and dopant compounds, respectively, in Examples 1 to 15. The properties of the organic light-emitting devices were measured at 10 mA/cm.sup.2. The structures of [HT] and [BD1] are as follows.

TABLE-US-00001 TABLE 1 [HT] [BD1] [00196] [00197] Hole Dopant External transport compound quantum layer (Formula Voltage efficiency Item (Formula A) B/C/D) (V) (%) Example 1 12 1 3.6 11.4 Example 2 30 1 3.6 11.7 Example 3 44 1 3.5 11.8 Example 4 78 1 3.5 11.8 Example 5 174 1 3.6 11.2 Example 6 30 33 3.6 11.5 Example 7 44 33 3.5 11.7 Example 8 78 33 3.5 11.9 Example 9 102 33 3.6 11.4 Example 10 195 33 3.6 11.6 Example 11 44 95 3.5 12.0 Example 12 78 95 3.5 12.2 Example 13 102 95 3.6 11.6 Example 14 174 95 3.6 11.5 Example 15 195 95 3.6 11.4 Comparative Example 1 HT 1 3.8 8.6 Comparative Example 2 HT 33 3.7 8.4 Comparative Example 3 HT 95 3.7 8.8 Comparative Example 4 12 BD 1 3.8 7.7 Comparative Example 5 44 BD 1 3.8 7.9 Comparative Example 6 78 BD 1 3.7 8.0 Comparative Example 7 102 BD 1 3.7 7.8 Comparative Example 8 195 BD 1 3.8 7.6

[0109] As can be seen from [Table 1] above, the organic light-emitting device according to the present invention using the hole transport material (Formula A) in the hole transport layer, and using the dopant materials (Formula B/C/D) according to the present invention in the light-emitting layer can be operated at a lower voltage and exhibit improved luminous efficacy based on remarkably improved external quantum efficiency compared to the organic light-emitting device using the conventional compound represented by HT, the organic light-emitting device using the conventional compound represented by BD1, and the organic light-emitting device without using the combination of materials according to the present invention.

INDUSTRIAL APPLICABILITY

[0110] The organic light-emitting device according to the present invention can be operated at a lower driving voltage and exhibits excellent external quantum efficiency and thus high luminous efficacy by utilizing the compounds having characteristic structures as a hole transport material and a dopant material, respectively, in the hole injection layer or the hole transport layer, and the light-emitting layer, and thus is industrially applicable to flat panel displays, flexible displays, monochromatic or white flat panel lighting systems, monochromatic or white flexible lighting systems, vehicle displays, displays for virtual or augmented reality and the like.