Specific ladder type compounds for organic light emitting devices

Abstract

The present invention relates to a compound of formula (I), wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are each independently hydrogen or R.sup.a, with proviso that a pair of two substituents selected from R.sup.1 and R.sup.2, R.sup.2 and R.sup.3, and R.sup.3 and R.sup.4 is linked to one another and forms a group of formula (II); a material for an organic electroluminescence device comprising at least one compound of formula (I); an organic electroluminescence device which comprises an organic thin film layer be-tween an anode and a cathode, wherein the organic thin film layer comprises one or more layers and comprises a light emitting layer, and at least one layer of the organic thin film layer comprises at least one compound of formula (I); and an electronic equipment comprising the inventive organic electroluminescence device. ##STR00001##

Claims

1. A compound of formula (I): ##STR00081## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are each independently hydrogen or R.sup.a, with proviso that a pair of two substituents selected from R.sup.2 and R.sup.3, and R.sup.3 and R.sup.4 is linked to one another and forms a group of formula (II): ##STR00082## wherein Ar.sub.1 represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms or a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms; dotted lines are bonding sites; R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9, R.sup.10, R.sup.15, R.sup.16 and R.sup.a are each independently hydrogen, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms; a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms; a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms; a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms; a substituted or unsubstituted aralkyl group having 7 to 31 ring carbon atoms; a di-substituted amino group having a substituent selected from a group consisting of a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms and a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms; a substituted or unsubstituted alkoxy group having I to 30 carbon atoms; a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms; a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms; a substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms; a mono-, di-, or tri-substituted silyl group having a substituent selected from a group consisting of a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms and a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms; a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms; a halogen atom; a cyano group; a nitro group; a sulfonyl group having a substituent selected from a group consisting of a substituted or unsubstituted alkyl group having I to 30 carbon atoms and a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms; a di-substituted phosphoryl group having a substituent selected from a group consisting of a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms and a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms; an alkylcarbonyloxy group having 2 to 31 carbon atoms; an arylcarbonyloxy group having 6 to 30 ring carbon atoms; or a boron-containing group; R.sup.15 and R.sup.16 are optionally bonded to each other to form a ring structure; two or more substituents selected from R.sup.a, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9 and R.sup.10 are optionally bonded to each other to form a ring structure; A is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms; or a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, or a disubstituted amino group; L is a single bond, a substituted or unsubstituted alkylene group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkylene group having 3 to 30 carbon atoms, a substituted divalent silyl group having 2 to 30 carbon atoms, a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted divalent heterocyclic group having 5 to 30 ring atoms; and l is 0, 1, 2 or 3.

2. The compound according to claim 1, wherein the group of formula (II) is represented by formula (IIb): ##STR00083## wherein Q.sup.1 is CR.sup.11 or N; Q.sup.2 is CR.sup.12 or N; Q.sup.3 is CR.sup.13 or N and Q.sup.4 is CR.sup.14 or N; dotted lines are bonding sites; R.sup.11, R.sup.12, R.sup.13 and R.sup.14 are each independently hydrogen, a substituted or unsubstituted alkyl group having I to 30 carbon atoms; a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms; a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms; a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms; a substituted or unsubstituted aralkyl group having 7 to 31 ring carbon atoms; a di-substituted amino group having a substituent selected from a group consisting of a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms and a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms; a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms; a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms; a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms; a substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms; a mono-, di-, or tri-substituted silyl group having a substituent selected from a group consisting of a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms and a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms; a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms; a halogen atom; a cyano group; a nitro group; a sulfonyl group having a substituent selected from a group consisting of a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms and a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms; a di-substituted phosphoryl group having a substituent selected from a group consisting of a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms and a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms; an alkylcarbonyloxy group having 2 to 31 carbon atoms; an arylcarbonyloxy group having 6 to 30 ring carbon atoms; or a boron-containing group; and two or more substituents selected from R.sup.11, R.sup.12, R.sup.13 and R.sup.14 are optionally bonded to each other to form a ring structure.

3. The compound according to claim 1, wherein the compound is represented by a formula selected from the following formulae(Ic-1a), (Id-1a); (Ie-1a) and (If-1a): ##STR00084## ##STR00085## wherein R.sup.17, R.sup.18, R.sup.19 and R.sup.20 are each independently hydrogen, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms; a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms; a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms; a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms; a substituted or unsubstituted aralkyl group having 7 to 31 ring carbon atoms; a di-substituted amino group having a substituent selected from a group consisting of a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms and a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms; a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms; a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms; a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms; a substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms; a mono-, di-, or tri-substituted silyl group having a substituent selected from a group consisting of a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms and a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms; a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms; a halogen atom; a cyano group; a nitro group; a sulfonyl group having a substituent selected from a group consisting of a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms and a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms; a di-substituted phosphoryl group having a substituent selected from a group consisting of a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms and a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms; an alkylcarbonyloxy group having 2 to 31 carbon atoms; an arylcarbonyloxy group having 6 to 30 ring carbon atoms; or a boron-containing group; two or more substituents selected from R.sup.17, R.sup.18, R.sup.19 and R.sup.20 are optionally bonded to each other to form a ring structure; is a single bond, a substituted or unsubstituted alkylene group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkylene group having 3 to 30 carbon atoms, a substituted divalent silyl group having 2 to 30 carbon atoms, a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted divalent heterocyclic group having 5 to 30 ring atoms, and l is 0,1,2 or 3.

4. The compound according to claim 1, wherein A is represented by formula (III) ##STR00086## wherein X.sup.1, X.sup.2 and X.sup.3 each independently represent CR.sup.23 or an N atom, wherein each R.sup.23 are optionally the same or different: and R.sup.21, R.sup.22, R.sup.23 and R.sup.26 each independently represent hydrogen, a halogen atom, a substituted or unsubstituted alkyl group having I to 30 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 31 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms, a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, a substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms, a substituted silyl group having 3 to 60 carbon atoms, or a cyano group, provided that, among R.sup.21, R.sup.22, R.sup.26 and R.sup.23, if X.sup.1, X.sup.2 and/or X.sup.3 are CR.sup.23, any two of R.sup.21, R.sup.22, R.sup.23 and R.sup.26 are optionally bonded each other to form ring structures; wherein one of R.sup.21, R.sup.22, R.sup.26 and, if X.sup.1, X.sup.2 and/or X.sup.3 are CR.sup.23, R.sup.23, represents a bonding site to -(L).sub.l-.

5. The compound according to claim 1, wherein A is represented by a formula selected from (IIIa), (IIIb), (IIIc), (IIId), (IIIe), and (IIIf): ##STR00087## wherein Y.sup.1 and Y.sup.2 each independently represent O, S, NR.sup.43 or CR.sup.44R.sup.45; and R.sup.21, R.sup.22, R.sup.23, R.sup.26, R.sup.31, R.sup.32, R.sup.33, R.sup.34, R.sup.35, R.sup.36, R.sup.37, R.sup.38, R.sup.39, R.sup.40, R.sup.41, R.sup.42, R.sup.43, R.sup.44 and R.sup.45 each independently represent hydrogen, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms, a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, a substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms, a substituted silyl group having 3 to 60 carbon atoms, or a cyano group, provided that, among from R.sup.21, R.sup.22, R.sup.23, R.sup.31, R.sup.32, R.sup.33, R.sup.34, R.sup.35, R.sup.36, R.sup.37, R.sup.38, R.sup.39, R.sup.40, R.sup.41 and R.sup.42, any two of from R.sup.21, R.sup.22, R.sup.23, R.sup.31, R.sup.32, R.sup.33, R.sup.34, R.sup.35, R.sup.36, R.sup.37, R.sup.38, R.sup.39, R.sup.40, R.sup.41 and R.sup.42 are optionally bonded each other to form ring structures, wherein one of R.sup.21, R.sup.22, R.sup.23, R.sup.26, R.sup.31, R.sup.32, R.sup.33, R.sup.34, R.sup.35, R.sup.36, R.sup.37, R.sup.38, R.sup.39, R.sup.40, R.sup.41, R.sup.42, R.sup.43, R.sup.44 and R.sup.45 represents a bonding site to -(L).sub.l-.

6. The compound according to claim 1 wherein is represented by formula (IVa): ##STR00088## wherein Y.sup.3 represents O, S or NR.sup.48; R.sup.46, R.sup.47 and R.sup.48 each independently represent a halogen atom, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms, a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, a substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms, a substituted silyl group having 3 to 60 carbon atoms, or a cyano group; a is 0, 1, 2, 3 or 4; and b is 0, 1, 2, 3 or 4, when a is more than 1, the R.sup.46s are optionally the same or different and are allowed to be bonded to each other to form a ring structure, when b is more than 1, the R.sup.47s are optionally the same or different and are allowed to be bonded to each other to form a ring structure, wherein one of R.sup.46, R.sup.47 and R.sup.48 represents a bonding site to -(L).sub.l-.

7. The compound according to claim 1, wherein A represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms.

8. The compound according to claim 1, wherein A represents a substituted or unsubstituted aromatic hydrocarbon group selected from the group consisting of phenyl, naphthyl, phenanthryl, triphenylenyl, fluorenyl and fluoranthenyl.

9. A material for an organic electroluminescence device comprising at least one compound according to claim 1.

10. An organic electroluminescence device which comprises an organic thin film layer between an anode and a cathode, wherein the organic thin film layer comprises one or more layers and comprises a light emitting layer, and at least one layer of the organic thin film layer comprises at least one compound according to claim 1.

11. The organic electroluminescence device according to claim 10, wherein the light emitting layer comprises the compound.

12. The organic electroluminescence device according to claim 10, wherein the light emitting layer comprises a phosphorescent material, which is an ortho-metallated complex comprising a metal atom selected from the group consisting of iridium, osmium and platinum.

13. The organic electroluminescence device according to claim 10, wherein an electron transporting layer is provided between the cathode and the light emitting layer, and the electron transporting layer comprises the compound.

14. The organic electroluminescence device according to claim 10, wherein an electron transporting layer is provided between the cathode and the light emitting laver, and the electron transporting layer comprises the compound.

15. An electronic equipment comprising the organic electroluminescence device according to claim 10.

Description

EXAMPLES

I Synthesis Examples

Synthesis Example 1

Synthesis Example 1-1

(1) ##STR00069##

(2) In a nitrogen flushed 500 ml three-necked round-bottomed flask 1-aminodibenzofuran (9.2 g, 50 mmol) was dissolved in carbon tetrachloride (250 ml) under nitrogen. N-chlorosuccinimide (6.3 g, 47.5 mmol) was added to the reaction mixture. The reaction mixture was heated to 90° C. with an oil bath for 2 hours. The solvent was evaporated and the residue was dissolved in methyl tert-butyl ether and then washed with water and brine. The crude product was added to a silica gel column and was eluted with heptane and toluene to give 8.9 g of white solid (82% yield). The identification of the intermediate 1 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 1-2

(3) ##STR00070##

(4) In a nitrogen flushed 1000 ml three-necked round-bottomed flask intermediate 1 (6.5 g, 30 mmol), 2-bromo-9,9-dimethylfluorene (6.8 g, 25 mmol), (±)-2,2′-bis(diphenylphosphino)-1,1′-binaphthalene (1.5 g, 2.4 mmol), palladium(II) acetate (0.27 g, 1.2 mmol) and sodium tert-butoxide (5.77 g, 60 mmol) were dissolved in xylene under nitrogen. The reaction mixture was heated 145° C. with an oil bath for 5 hours. The reaction mixture was diluted with ethyl acetate, and the insoluble salts were filtrated. The organic phase was washed with water. The crude product was added to a silica gel column and was eluted with heptane and toluene and to give 8.85 g of white solid (86% yield). The identification of the intermediate 2 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 1-3

(5) ##STR00071##

(6) In a nitrogen flushed 350 ml three-necked round-bottomed flask intermediate 2 (8.2 g, 20 mmol), tricyclohexylphosphine tetrafluoroborate (1.2 g, 3.2 mmol), palladium(II) acetate (0.36 g, 1.6 mmol) and potassium carbonate (5.5 g, 40 mmol) were dissolved in N,N-dimethylacetamide under nitrogen. The reaction mixture was heated 145° C. with an oil bath for 22 hours. The reaction mixture was filtrated and the most of N,N-dimethylacetamide was evaporated. Water was added to the crude product followed by extraction with ethyl acetate and then washed with water. The crude product was added to a silica gel column and was eluted with heptane and toluene and to give 4.28 g of yellow solid (57% yield). The identification of the intermediate 3 was made by FD-MS (field desorption mass spectrometry) analysis.

Synthesis Example 1-4

(7) ##STR00072##

(8) In a nitrogen flushed 100 ml three-necked round-bottomed flask intermediate 3 (1.5 g, 4.2 mmol), 2-(3-bromophenyl)-4,6-diphenyl-1,3,5-triazine (1.6 g, 4.2 mmol), 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (0.1 g, 0.17 mmol), tris(dibenzylideneacetone)dipalladium(0) (0.077 g, 0.084 mmol) and sodium tert-butoxide (1.2 g, 12.6 mmol) were dissolved in xylene under nitrogen. The reaction mixture was heated 145° C. with an oil bath for 3 hours. The reaction mixture was diluted with methanol, and the precipitate solid was filtrated then washed with methanol and water. The crude product was added to a silica gel column and was eluted with heptane and toluene and to give 2.33 g of white solid (90% yield).

(9) The compound was measured for FD-MS (field desorption mass spectrometry), maximum ultraviolet absorption wavelength (UV(PhMe) λmax) in toluene, and maximum fluorescence wavelength (FL (PhMe, λex=350 nm) λmax) in toluene. The result is shown below.

(10) FDMS: calcd. for C48H32N4O=680, found m/z=680 (M+)

(11) FL (PhMe, λex=350 nm) λmax: 482 nm

Synthesis Example 2-1

(12) ##STR00073##

(13) The procedure of the synthesis of compound 1 was repeated except for using 2-(4-bromophenyl)-4,6-diphenyl-1,3,5-triazine in place of 2-(3-bromophenyl)-4,6-diphenyl-1,3,5-triazine. The compound was measured for FD-MS (field desorption mass spectrometry) and maximum fluorescence wavelength (FL (PhMe, λex=350 nm) λmax) in toluene. The result is shown below.

(14) FDMS: calcd. for C48H32N4O=680, found m/z=680 (M+)

(15) FL (PhMe, λex=350 nm) λmax: 462 nm

Synthesis Example 3-1

(16) ##STR00074##

(17) The procedure of the synthesis of compound 1 was repeated except for using 2-chloro-4,6-diphenyl-1,3,5-triazine in place of 2-(3-bromophenyl)-4,6-diphenyl-1,3,5-triazine. The compound was measured for FD-MS (field desorption mass spectrometry) and maximum fluorescence wavelength (FL (PhMe, λex=350 nm) λmax) in toluene. The result is shown below.

(18) FDMS: calcd. for C42H28N4O=604, found m/z=604 (M+)

(19) FL (PhMe, λex=350 nm) λmax: 529 nm

II Application Example

Application Example 1

(20) A glass substrate with 120 nm-thick indium-tin-oxide (ITO) transparent electrode (manufactured by Geomatec Co., Ltd.) used as an anode was first cleaned with isopropanol in an ultrasonic bath for 10 min. To eliminate any possible organic residues, the substrate was exposed to an ultraviolet light and ozone for further 30 min. This treatment also improves the hole injection properties of the ITO. The cleaned substrate was mounted on a substrate holder and loaded into a vacuum chamber. Thereafter, the organic materials specified below were applied by vapor deposition to the ITO substrate at a rate of approx. 0.2-1 Å/sec at about 10.sup.−6-10.sup.−8 mbar. As a hole injection layer, 5 nm-thick of compound HI was applied. Then 100 nm-thick of compound HT1 and 60 nm-thick compound HT2 were applied as hole transporting layer 1 and hole transporting layer 2, respectively. Subsequently, a mixture of 5% by weight of an emitter compound (tris[2-phenylpyridinato-C.sup.2,N])iridium(III), 47.5% by weight of a host (compound 1) and 47.5% by weight of compound PH1 were applied to form a 40 nm-thick phosphorescent-emitting layer. On the emitting layer, 30 nm-thick compound ET was applied as an electron transport layer. Finally, 1 nm-thick LiF was deposited as an electron injection layer and 80 nm-thick Al was then deposited as a cathode to complete the device. The device was sealed with a glass lid and a getter in an inert nitrogen atmosphere with less than 1 ppm of water and oxygen. To characterize the OLED, electroluminescence spectra were recorded at various currents and voltages. In addition, the current-voltage characteristic was measured in combination with the luminance to determine luminous efficiency and external quantum efficiency (EQE). Driving voltage (Voltage) is given at a current density of 10 mA/cm.sup.2. The device results are shown in Table 1.

(21) ##STR00075## ##STR00076##

Comparative Application Example 1

(22) Application Example 1 was repeated except for using the compound shown in place of the host (compound 1). The device result is shown in Table 1.

(23) TABLE-US-00001 TABLE 1 Appl. Ex. Host Voltage [V] CIE(x, y) Appl. Ex. 1 Compound 1 4.9 0.31, 0.63 Comp. Appl. Ex. 1 Comparative 5.2 0.31, 0.63 Compound 1

(24) ##STR00077## ##STR00078##

(25) The results shown in Table 1 demonstrate that the voltage was improved in the case that an inventive compound 1 was used as green hosts together with a co-host Compound PH1 in an OLED.

Application Example 2

(26) Application Example 1 was repeated except for using a host compound PH2 in place of the host (compound PH1). The device result is shown in Table 2.

Comparative Application Examples 2-4

(27) Application Example 2 was repeated except for using each compound shown in table 2 in place of the host (compound 1). The device results are shown in Table 2.

(28) To characterize the OLED, electroluminescence spectra were recorded at various currents and voltages. In addition, the current-voltage characteristic was measured in combination with the luminance to determine luminous efficiency and external quantum efficiency (EQE). Driving voltage (Voltage) is given at a current density of 10 mA/cm.sup.2, and 80% lifetime (LT80), the time spent until the initial luminance at 50 mA/cm.sup.2 is reduced to 80%, is recorded. The device results are shown in Table 2.

(29) TABLE-US-00002 TABLE 2 Appl. Ex. Host Voltage [V] LT80 [hrs] CIE(x, y) Appl. Ex. 2 Compound 1 4.9 160 0.31, 0.63 Comp. Appl. Comparative 5.4 50 0.32, 0.63 Ex. 2 Compound 2 Comp. Appl. Comparative 5.3 100 0.31, 0.63 Ex. 3 Compound 3 Comp. Appl. Comparative 5.2 90 0.31, 0.63 Ex. 4 Compound 4

(30) The results shown in Table 2 demonstrate that the lifetime and voltage were improved in the case that an inventive compound 1 was used as a green host together with a co-host Compound PH2 in anOLED.

Application Example 3, Comparative Application Example 5

(31) Application Example 1 was repeated except for using the compounds shown in the Table 3 in place of the hosts compound 1 and PH1. The device result is shown in Table 3.

(32) TABLE-US-00003 TABLE 3 Appl. Ex. Host 1 Host 2 Voltage [V] CIE(x, y) Appl. Ex. 3 Compound 2 PH3 4.9 0.31, 0.63 Comp. Appl. Comparative PH3 5.2 0.31, 0.63 Ex. 5 Compound 1

(33) ##STR00079##

(34) The results shown in Table 3 demonstrate that the voltage was improved in the case that an inventive compound 2 was used as green hosts together with a co-host Compound PH3 in an OLED.

Application Example 4, Comparative Application Example 6

(35) Application Example 1 was repeated except for using the compounds shown in the Table 4 in place of the hosts compound 1 and PH1.

(36) To characterize the OLED, electroluminescence spectra were recorded at various currents and voltages. In addition, the current-voltage characteristic was measured in combination with the luminance to determine luminous efficiency and external quantum efficiency (EQE). Driving voltage (Voltage) is given at a current density of 10 mA/cm.sup.2, and 80% lifetime (LT80), the time spent until the initial luminance at 50 mA/cm.sup.2 is reduced to 80%, is recorded. The device results are shown in Table 4.

(37) TABLE-US-00004 TABLE 4 Voltage LT80 Appl. Ex. Host 1 Host 2 [V] [hrs] CIE(x, y) Appl. Ex. 4 Compound 3 PH3 5.0 140 0.31, 0.63 Comp. Appl. Comparative PH3 5.4 60 0.31, 0.63 Ex. 6 Compound 5

(38) ##STR00080##

(39) The results shown in Table 4 demonstrate that the lifetime and voltage were improved in the case that an inventive compound 3 was used as a green host together with a co-host Compound PH3 in anOLED.