Patent Grant
7888863
The present invention relates to novel organic electroluminescent compounds, and organic electroluminescent devices employing the same as electroluminescent material. Specifically, the organic electroluminescent compounds according to the present invention are represented by Chemical Formula (1):
wherein, A and B independently represent CR7 or N, provided that both A and B cannot be CR7 or N at the same time; and X is O or S.
Three electroluminescent materials (for red, green and blue) are employed to realize a full-colored OLED display. The important issue is to develop red, green and blue electroluminescent materials with high efficiency and long life in order to enhance the overall feature of the organic electroluminescent (EL) devices. From the aspect of function, the EL materials are classified into host materials and dopant materials. It is generally known that a device structure having the most excellent EL properties can be fabricated with an EL layer prepared by doping a dopant to a host. Recently, development of an organic EL device with high efficiency and long life comes to the fore as an urgent subject, and particularly urgent is development of a material with far better EL properties as compared to conventional EL materials as considering EL properties required for a medium to large sized OLED panel. From this point of view, development of host material is one of the most important issues to be settled. The desired properties for the host material (serving as a solvent and energy conveyer in solid state) are high purity and appropriate molecular weight to enable vapor-deposition in vacuo. In addition, glass transition temperature and thermal decomposition temperature should be high enough to ensure thermal stability. Further, the host material should have high electrochemical stability for providing long life. It is to be easy to form an amorphous thin film, with high adhesiveness to other adjacent materials but without interlayer migration.
In the meanwhile, for blue materials, a number of materials have been developed and commercialized since the development of diphenylvinyl-biphenyl (DPVBi) (Compound a) by Idemitsu-Kosan. In addition to the blue material system from Idemitsu-Kosan, dinaphthylanthracene (DNA) (Compound b), tetra(t-butyl)perylene (Compound c) system or the like have been known. However, extensive research and development should be performed with respect to these materials. The distryl compound system of Idemitsu-Kosan, which is known to have highest efficiency up to now, has 6 lm/W of power efficiency and beneficial device lifetime of more than 30,000 hr. However, when it is applied to a full-colored display, the lifetime is merely several thousand hours, owing to decrease of color purity over operation time. In case of blue electroluminescence, it becomes advantageous from the aspect of the luminous efficiency, if the electroluminescent wavelength is shifted a little toward longer wavelength. However, it is not easy to apply the material to a display of high quality because of unsatisfactory color purity in blue. Furthermore, the research and development of such materials are urgent because of the problems in color purity, efficiency and thermal stability.
In order to develop a host material with high efficiency and long life, compounds based on different backbones have been disclosed, such as dispiro-prolene-anthracene (TBSA), ter-spirofluorene (TSF) and bitriphenylene (BTP). These compounds, however, did not result in color purity and luminous efficiency at a sufficient level.
The compound TBSA as reported by Gyeongsang National University and Samsung SDI (Kwon, S. K. et al., Advanced Materials, 2001, 13, 1690; Japanese Patent Laid-Open JP 2002121547), showed luminous efficiency of 3 cd/A at 7.7 V, and relatively good color coordinate of (0.15, 0.11), but it was applied as a material for single layer, being inappropriate for practical use. The compound TSF reported by Taiwan National University (Wu, C.-C. et al., Advanced Materials, 2004, 16, 61; US Patent Publication US 2005040392) showed relatively good external quantum efficiency of 5.3%, but it was still inappropriate for practical use. The compound BTP reported by Chingwha National University of Taiwan (Cheng, C.-H. et al., Advanced Materials, 2002, 14, 1409; US Patent Publication US 2004076852) showed luminous efficiency of 2.76 cd/A and relatively good color coordinate of (0.16, 0.14), but this was still insufficient for practical use.
As described above, conventional materials are constituted of a single layer, not forming a host-dopant thin layer, and is difficult to be used practically from the aspect of color purity and efficiency. There are not enough data reliable, with respect to its long life.
In the meanwhile, according to a patent application of Mitsui Chemicals (Japan) (US Patent Publication U.S. Pat. No. 7,166,240), the compounds shown below have the absorption spectra at 390 to 430 nm, with luminous efficiency of 4.6 cd/A. However, on the basis of these data, the compounds with above absorption wavelength range, electroluminescence of greenish blue color is anticipated, and the Patent Publication indicates the color as bluish green color.
Particularly, embodiment of pure blue color is impossible with the symmetrical structure of the Patent Publication, and the material, which cannot provide pure blue luminescence, is inadequate to be practically applied to a full-colored display.
With intensive efforts to overcome the problems of conventional techniques as described above, the present inventors have invented novel electroluminescent compounds to realize an organic electroluminescent device having excellent luminous efficiency and surprisingly improved lifetime.
The object of the present invention is to provide organic electroluminescent compounds having the backbone to give more excellent luminous efficiency, longer device life and appropriate color coordinate, as compared to those of conventional host materials, with overcoming disadvantages of them.
Another object of the invention is to provide organic electroluminescent devices of high efficiency and long life, which employ said organic electroluminescent compounds as electroluminescent material.
Still another object of the invention is to provide organic solar cells comprising said organic electroluminescent compounds.
Thus, the present invention relates to organic electroluminescent compounds represented by Chemical Formula (1), and organic electroluminescent devices comprising the same. Since the organic electroluminescent compounds according to the invention have good luminous efficiency and excellent color purity and life property of material, OLED's having very good operation life can be manufactured therefrom:
In Chemical Formula (1), A and B independently represent CR7 or N, provided that both A and B cannot be CR7 or N at the same time;
X is O or S;
R1 through R7 independently represent hydrogen, deuterium, halogen, (C1-C60)alkyl, (C6-C60)aryl, (C3-C60)heteroaryl, 5- or 6-membered heterocycloalkyl containing one or more heteroatom(s) selected from N, O and S, (C3-C60)cycloalkyl, tri(C1-C60)alkylsilyl, di(C1-C60)alkyl(C6-C60)arylsilyl, tri(C6-C60)arylsilyl, adamantyl, (C7-C60)bicycloalkyl, (C2-C60)alkenyl, (C2-C60)alkynyl, (C1-C60)alkoxy, cyano, (C1-C60)alkylamino, (C6-C60)arylamino, (C6-C60)ar(C1-C60)alkyl, (C6-C60)aryloxy, (C6-C60)arylthio, (C1-C60)alkoxycarbonyl, carboxyl, nitro or hydroxyl, or R3 and R4 or R5 and R6 may be linked via (C3-C60)alkylene or (C3-C60)alkenylene to form a fused ring; the alkylene or alkenylene may be further substituted by one or more substituent(s) selected from deuterium, halogen, (C1-C60)alkyl, (C6-C60)aryl, (C3-C60)heteroaryl, 5- or 6-membered heterocycloalkyl containing one or more heteroatom(s) selected from N, O and S, (C3-C60)cycloalkyl, tri(C1-C60)alkylsilyl, di(C1-C60)alkyl(C6-C60)arylsilyl, tri(C6-C60)arylsilyl, adamantyl, (C7-C60)bicycloalkyl, (C2-C60)alkenyl, (C2-C60)alkynyl, (C1-C60)alkoxy, cyano, (C1-C60)alkylamino, (C6-C60)arylamino, (C6-C60)ar(C1-C60)alkyl, (C6-C60)aryloxy, (C6-C60)arylthio, (C1-C60)alkoxycarbonyl, carboxyl, nitro and hydroxyl;
Ar1 and Ar2 independently represent (C6-C60)aryl, (C3-C60)heteroaryl, 5- or 6-membered heterocycloalkyl containing one or more heteroatom(s) selected from N, O and S, (C3-C60)cycloalkyl, adamantyl, (C7-C60)bicycloalkyl, or a substituent selected from the following structures:
wherein, R11 through R23 independently represent hydrogen, deuterium, halogen, (C1-C60)alkyl, (C6-C60)aryl, (C3-C60)heteroaryl, 5- or 6-membered heterocycloalkyl containing one or more heteroatom(s) selected from N, O and S, (C3-C60)cycloalkyl, tri(C1-C60)alkylsilyl, di(C1-C60)alkyl(C6-C60)arylsilyl, tri(C6-C60)arylsilyl, adamantyl, (C7-C60)bicycloalkyl, (C2-C60)alkenyl, (C2-C60)alkynyl, (C1-C60)alkoxy, cyano, (C1-C60)alkylamino, (C6-C60)arylamino, (C6-C60)ar(C1-C60)alkyl, (C6-C60)aryloxy, (C6-C60)arylthio, (C1-C60)alkoxycarbonyl, carboxyl, nitro or hydroxyl; or each of R11 through R23 may be linked to an adjacent substituent via (C3-C60)alkylene or (C3-C60)alkenylene with or without a fused ring to form an alicyclic ring, or a monocyclic or polycyclic aromatic ring;
D and E independently represent a chemical bond, —(CR31R32)a—, —N(R33)—, —S—, —O—, —Si(R34)(R35)—, —P(R36)—, —C(═O)—, —B(R37)—, —In(R38)—, —Se—, —Ge(R39)(R40)—, —Sn(R41)(R42)—, —Ga(R43)— or —(R44)C═C(R45)—;
R31 through R45 independently represent hydrogen, deuterium, halogen, (C1-C60)alkyl, (C6-C60)aryl, (C3-C60)heteroaryl, 5- or 6-membered heterocycloalkyl containing one or more heteroatom(s) selected from N, O and S, (C3-C60)cycloalkyl, tri(C1-C60)alkylsilyl, di(C1-C60)alkyl(C6-C60)arylsilyl, tri(C6-C60)arylsilyl, adamantyl, (C7-C60)bicycloalkyl, (C2-C60)alkenyl, (C2-C60)alkynyl, (C1-C60)alkoxy, cyano, (C1-C60)alkylamino, (C6-C60)arylamino, (C6-C60)ar(C1-C60)alkyl, (C6-C60)aryloxy, (C6-C60)arylthio, (C1-C60)alkoxycarbonyl, carboxyl, nitro or hydroxyl, or R31, and R32, R34 and R35, R39 and R40, R41 and R42 or R44 and R45 may be linked via (C3-C60)alkylene or (C3-C60)alkenylene with or without a fused ring to form an alicyclic ring, or a monocyclic or polycyclic aromatic ring;
the alkyl, aryl, heteroaryl, heterocycloalkyl, cycloalkyl, trialkylsilyl, dialkylarylsilyl, triarylsilyl, adamantyl, bicycloalkyl, alkenyl, alkynyl, alkylamino or arylamino of R1 through R7, Ar1, Ar2, R11 through R23 and R31 through R45 may be further substituted by deuterium, halogen, (C1-C60)alkyl, (C6-C60)aryl, (C3-C60)heteroaryl, 5- or 6-membered heterocycloalkyl containing one or more heteroatom(s) selected from N, O and S, (C3-C60)cycloalkyl, tri(C1-C60)alkylsilyl, di(C1-C60)alkyl(C6-C60)arylsilyl, tri(C6-C60)arylsilyl, adamantyl, (C7-C60)bicycloalkyl, (C2-C60)alkenyl, (C2-C60)alkynyl, (C1-C60)alkoxy, cyano, (C1-C60)alkylamino, (C6-C60)arylamino, (C6-C60)ar(C1-C60)alkyl, (C6-C60)aryloxy, (C6-C60)arylthio, (C1-C60)alkoxycarbonyl, carboxyl, nitro or hydroxyl; and
a is an integer from 1 to 4.
Referring now to the Drawings,
The term “alkyl” includes saturated linear or branched monovalent hydrocarbon radicals consisting only of carbon atoms and hydrogen atoms, or combinations thereof. The term “alkoxy” means —O-alkyl groups, wherein the “alkyl” is defined as above.
The term “aryl” described herein means an organic radical derived from aromatic hydrocarbon via elimination of one hydrogen atom. Each ring suitably comprises a monocyclic or fused ring system containing from 4 to 7, preferably from 5 to 6 cyclic atoms. Further, “aryl” includes the structures wherein more than one aryls are bonded via chemical bond(s). Specific examples include phenyl, naphthyl, biphenyl, anthryl, indenyl, fluorenyl, phenanthryl, triphenylenyl, pyrenyl, perylenyl, chrysenyl, naphthacenyl and fluoranthenyl, but they are not restricted thereto.
The naphthyl of the compounds according to the invention may be 1-naphthyl or 2-naphthyl; the anthryl may be 1-anthryl, 2-anthryl or 9-anthryl; and the fluorenyl may be 1-fluorenyl, 2-fluorenyl, 3-fluorenyl, 4-fluorenyl or 9-fluorenyl.
The term “heteroaryl” described herein means an aryl group containing from 1 to 4 heteroatom(s) selected from N, O and S for the aromatic cyclic backbone atoms, and carbon atom(s) for remaining aromatic cyclic backbone atoms. The heteroaryl may be a 5- or 6-membered monocyclic heteroaryl or a polycyclic heteroaryl which is fused with one or more benzene ring(s), and may be partially saturated. Further, “heteroaryl” includes the structures wherein more than one heteroaryls are bonded via chemical bond(s). The heteroaryl groups may include divalent aryl groups of which the heteroatoms are oxidized or quarternized to form N-oxides, quaternary salts, or the like. Specific examples include monocyclic heteroaryl groups such as furyl, thiophenyl, pyrrolyl, imidazolyl, pyrazolyl, thiazolyl, thiadiazolyl, isothiazolyl, isoxazolyl, oxazolyl, oxadiazolyl, triazinyl, tetrazinyl, triazolyl, tetrazolyl, furazanyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl; polycyclic heteroaryl groups such as benzofuranyl, benzothiophenyl, isobenzofuranyl, benzimidazolyl, benzothiazolyl, benzisothiazolyl, benzisoxazolyl, benzoxazolyl, isoindolyl, indolyl, indazolyl, benzothiadiazolyl, quinolyl, isoquinolyl, cinnolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenanthridinyl and benzodioxolyl; and corresponding N-oxides (for example, pyridyl N-oxide, quinolyl N-oxide) and quaternary salts thereof; but they are not restricted thereto.
The substituents comprising “(C1-C60)alkyl” moiety described herein may contain 1 to 60 carbon atoms, 1 to 20 carbon atoms, or 1 to 10 carbon atoms. The substituents comprising “(C6-C60)aryl” moiety may contain 6 to 60 carbon atoms, 6 to 20 carbon atoms, or 6 to 12 carbon atoms. The substituents comprising “(C3-C60)heteroaryl” moiety may contain 3 to 60 carbon atoms, 4 to 20 carbon atoms, or 4 to 12 carbon atoms. The substituents comprising “(C3-C60)cycloalkyl” moiety may contain 3 to 60 carbon atoms, 3 to 20 carbon atoms, or 3 to 7 carbon atoms. The substituents comprising “(C2-C60)alkenyl or alkynyl” moiety may contain 2 to 60 carbon atoms, 2 to 20 carbon atoms, or 2 to 10 carbon atoms.
The organic electroluminescent compound according to the invention may be exemplified by the compounds represented by one of Chemical Formulas (2) to (4):
wherein, Ar1, Ar2, X and R1 through R7 are defined as in Chemical Formula (1); and
R51 through R54 independently represent hydrogen, deuterium, halogen, (C1-C60)alkyl, (C6-C60)aryl, (C3-C60)heteroaryl, 5- or 6-membered heterocycloalkyl containing one or more heteroatom(s) selected from N, O and S, (C3-C60)cycloalkyl, tri(C1-C60)alkylsilyl, di(C1-C60)alkyl(C6-C60)arylsilyl, tri(C6-C60)arylsilyl, adamantyl, (C7-C60)bicycloalkyl, (C2-C60)alkenyl, (C2-C60)alkynyl, (C1-C60)alkoxy, cyano, (C1-C60)alkylamino, (C6-C60)arylamino, (C6-C60)ar(C1-C60)alkyl, (C6-C60)aryloxy, (C6-C60)arylthio, (C1-C60)alkoxycarbonyl, carboxyl, nitro or hydroxyl, or R52 and R53 may be linked via (C3-C60)alkylene or (C3-C60)alkenylene with or without a fused ring to form an alicyclic ring, or a monocyclic or polycyclic aromatic ring.
In the chemical formulas, R1 through R7 independently represent hydrogen, deuterium, chloro, fluoro, methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, n-pentyl, i-pentyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, decyl, dodecyl, hexadecyl, benzyl, trifluoromethyl, perfluoroethyl, trifluoroethyl, perfluoropropyl, perfluorobutyl, methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, t-butoxy, n-pentoxy, i-pentoxy, n-hexyloxy, n-heptoxy, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, morpholino, thiomorpholino, phenyl, naphthyl, biphenyl, fluorenyl, phenanthryl, anthryl, fluoranthenyl, triphenylenyl, pyrenyl, chrysenyl, naphthacenyl, perylenyl, spirobifluorenyl, pyridyl, pyrrolyl, furanyl, thiophenyl, imidazolyl, benzimidazolyl, pyrazinyl, pyrimidinyl, pyridazinyl, quinolyl, triazinyl, benzofuranyl, benzothiophenyl, pyrazolyl, indolyl, carbazolyl, thiazolyl, oxazolyl, benzothiazolyl, benzoxazolyl, phenanthrolinyl, trimethylsilyl, triethylsilyl, tripropylsilyl, tri(t-butyl)silyl, t-butyldimethylsilyl, dimethylphenylsilyl, triphenylsilyl, adamantyl, bicyclo[2.2.1]heptyl, bicyclo[2.2.2]octyl, bicyclo[3.2.1]octyl, bicyclo[5.2.0]nonyl, bicyclo[4.2.2]decyl, bicyclo[2.2.2]octyl, 4-pentylbicyclo[2.2.2]octyl, ethenyl, phenylethenyl, ethynyl, phenylethynyl, cyano, dimethylamino, diphenylamino, monomethylamino, monophenylamino, phenyloxy, phenylthio, methoxycarbonyl, ethoxycarbonyl, t-butoxycarbonyl, carboxyl, nitro or hydroxyl.
In the formulas, Ar1 and Ar2 are independently selected from the following structures, but they are not restricted thereto:
wherein, R61 through R75 independently represent hydrogen, deuterium, halogen, (C1-C60)alkyl, (C6-C60)aryl, (C3-C60)heteroaryl, 5- or 6-membered heterocycloalkyl containing one or more heteroatom(s) selected from N, O and S, (C3-C60)cycloalkyl, tri(C1-C60)alkylsilyl, di(C1-C60)alkyl(C6-C60)arylsilyl, tri(C6-C60)arylsilyl, adamantyl, (C7-C60)bicycloalkyl, (C2-C60)alkenyl, (C2-C60)alkynyl, (C1-C60)alkoxy, cyano, (C1-C60)alkylamino, (C6-C60)arylamino, (C6-C60)ar(C1-C60)alkyl, (C6-C60)aryloxy, (C6-C60)arylthio, (C1-C60)alkoxycarbonyl, carboxyl, nitro or hydroxyl; the alkyl, aryl, heteroaryl, heterocycloalkyl, cycloalkyl, trialkylsilyl, dialkylarylsilyl, triarylsilyl, adamantyl, bicycloalkyl, alkenyl, alkynyl, alkylamino or arylamino of R61 through R75 may be further substituted by deuterium, halogen, (C1-C60)alkyl, (C6-C60)aryl, (C3-C60)heteroaryl, 5- or 6-membered heterocycloalkyl containing one or more heteroatom(s) selected from N, O and S, (C3-C60)cycloalkyl, tri(C1-C60)alkylsilyl, di(C1-C60)alkyl(C6-C60)arylsilyl, tri(C6-C60)arylsilyl, adamantyl, (C7-C60)bicycloalkyl, (C2-C60)alkenyl, (C2-C60)alkynyl, (C1-C60)alkoxy, cyano, (C1-C60)alkylamino, (C6-C60)arylamino, (C6-C60)ar(C1-C60)alkyl, (C6-C60)aryloxy, (C6-C60)arylthio, (C1-C60)alkoxycarbonyl, carboxyl, nitro or hydroxyl;
L1 and L2 independently represent a chemical bond, (C6-C60)arylene or (C3-C60)heteroarylene; the arylene or heteroarylene of L1 and L2 may be further substituted by one or more substituent(s) selected from deuterium, (C1-C60)alkyl, halogen, cyano, (C1-C60)alkoxy, (C3-C60)cycloalkyl, (C6-C60)aryl, (C3-C60)heteroaryl, adamantyl, (C7-C60)bicycloalkyl, cyano, (C1-C60)alkylamino, (C6-C60)arylamino, (C6-C60)ar(C1-C60)alkyl, (C6-C60)aryloxy, (C6-C60)arylthio, (C1-C60)alkoxycarbonyl, carboxyl, nitro, hydroxyl, tri(C1-C30)alkylsilyl, di(C1-C30)alkyl(C6-C30)arylsilyl and tri(C6-C30)arylsilyl;
F and G independently represent a chemical bond, —(CR81)(R82)—, —N(R83)—, —S—, —O—, —Si (R84)(R85)—, —P(R86)—, —C(═O)—, —B(R87)—, —In(R88)—, —Se—, —Ge(R89)(R90)—Sn (R91)(R92)— or —Ga(R93)—;
R81 through R93 independently represent hydrogen, deuterium, halogen, (C1-C60)alkyl, (C6-C60)aryl, (C3-C60)heteroaryl, 5- or 6-membered heterocycloalkyl containing one or more heteroatom(s) selected from N, O and S, (C3-C60)cycloalkyl, tri(C1-C60)alkylsilyl, di(C1-C60)alkyl(C6-C60)arylsilyl, tri(C6-C60)arylsilyl, adamantyl, (C7-C60)bicycloalkyl, (C2-C60)alkenyl, (C2-C60)alkynyl, (C1-C60)alkoxy, cyano, (C1-C60)alkylamino, (C6-C60)arylamino, (C6-C60)ar(C1-C60)alkyl, (C6-C60)aryloxy, (C6-C60)arylthio, (C1-C60)alkoxycarbonyl, carboxyl, nitro or hydroxyl; or R81 and R82, R84 and R85, R89 and R90, or R91 and R92 may be linked via (C3-C60)alkylene or (C3-C60)alkenylene with or without a fused ring to form an alicyclic ring, or a monocyclic or polycyclic aromatic ring; and
b is an integer from 1 to 5.
More specifically, Ar1 and Ar2 are independently selected from the following structures, but not restricted thereto:
More specifically, the organic electroluminescent compounds according to the present invention can be specifically exemplified by the following compounds, but they are not restricted thereto:
The organic electroluminescent compounds according to the present invention can be prepared as shown by Reaction Scheme (1):
wherein, A, B, X, Ar1, Ar2, and R1 through R6 are defined as in Chemical Formula (1).
The present invention also provides organic solar cells, which comprises one or more organic electroluminescent compound(s) represented by Chemical Formula (1).
The present invention also provides an organic electroluminescent device which is comprised of a first electrode; a second electrode; and at least one organic layer(s) interposed between the first electrode and the second electrode; wherein the organic layer comprises one or more organic electroluminescent compound(s) represented by Chemical Formula (1).
The organic electroluminescent device according to the present invention is characterized in that the organic layer comprises an electroluminescent region, which comprises one or more compound(s) represented by Chemical Formula (1) as electroluminescent host, and one or more dopant(s). The dopant applied to the organic electroluminescent device according to the invention is not particularly restricted, but preferably selected from the compounds represented by one of Chemical Formulas (5) to (7).
In Chemical Formula (5), R101 through R104 independently represent hydrogen, deuterium, halogen, (C1-C60)alkyl, (C6-C60)aryl, (C4-C60)heteroaryl, a 5- or 6-membered heterocycloalkyl containing one or more heteroatom(s) selected from N, O and S, (C3-C60)cycloalkyl, tri(C1-C60)alkylsilyl, di(C1-C60)alkyl(C6-C60)arylsilyl, tri(C6-C60)arylsilyl, adamantyl, (C7-C60)bicycloalkyl, (C2-C60)alkenyl, (C2-C60)alkynyl, (C1-C60)alkoxy, cyano, (C1-C60)alkylamino, (C6-C60)arylamino, (C6-C60)ar(C1-C60)alkyl, (C6-C60)aryloxy, (C1-C60)alkylthio, (C6-C60)arylthio, (C1-C60)alkoxycarbonyl, (C1-C60)alkylcarbonyl, (C6-C60)arylcarbonyl, carboxyl, nitro or hydroxyl, or each of R101 through R104 may be linked to an adjacent substituent via (C3-C60)alkylene or (C3-C60)alkenylene with or without a fused ring to form an alicyclic ring, or a monocyclic or polycyclic aromatic ring; and
the alkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, arylsilyl, alkylsilyl, alkoxy, aryloxy, arylthio, alkylamino, or arylamino of R101 through R104, or the alicyclic ring, or the monocyclic or polycyclic aromatic ring formed therefrom by linkage to an adjacent substituent via (C3-C60)alkylene or (C3-C60)alkenylene with or without a fused ring may be further substituted by one or more substituent(s) selected from halogen, deuterium, (C1-C60)alkyl, (C6-C60)aryl, (C4-C60)heteroaryl, a 5- or 6-membered heterocycloalkyl containing one or more heteroatom(s) selected from N, O and S, (C3-C60)cycloalkyl, tri(C1-C60)alkylsilyl, di(C1-C60)alkyl(C6-C60)arylsilyl, tri(C6-C60)arylsilyl, adamantyl, (C7-C60)bicycloalkyl, (C2-C60)alkenyl, (C2-C60)alkynyl, (C1-C60)alkoxy, cyano, (C1-C60)alkylamino, (C6-C60)arylamino, (C6-C60)ar(C1-C60)alkyl, (C6-C60)aryloxy, (C1-C60)alkylthio, (C6-C60)arylthio, (C1-C60)alkoxycarbonyl, (C1-C60)alkylcarbonyl, (C6-C60)arylcarbonyl, carboxyl, nitro and hydroxyl.
In Chemical Formula (7), Ar11 and Ar12 independently represent (C1-C60)alkyl, (C6-C60)aryl, (C4-C60)heteroaryl, (C6-C60)arylamino, (C1-C60)alkylamino, a 5- or 6-membered heterocycloalkyl containing one or more heteroatom(s) selected from N, O and S, or (C3-C60)cycloalkyl, or Ar11 and Ar12 may be linked via (C3-C60)alkylene or (C3-C60)alkenylene with or without a fused ring to form an alicyclic ring, or a monocyclic or polycyclic aromatic ring;
when c is 1, Ar13 represents (C6-C60)arylamino, (C6-C60)aryl, (C4-C60)heteroaryl, or a substituent represented by one of the following structural formulas:
when c is 2, Ar13 represents (C6-C60)arylene, (C4-C60)heteroarylene, or a substituent represented by one of the following structural formulas:
wherein Ar14 and Ar15 independently represent (C6-C60)arylene or (C4-C60)heteroarylene;
R111 through R113 independently represent hydrogen, deuterium, (C1-C60)alkyl or (C6-C60)aryl;
d is an integer from 1 to 4, e is an integer of 0 or 1; and
the alkyl, aryl, heteroaryl, arylamino, alkylamino, cycloalkyl or heterocycloalkyl of Ar11 and Ar12; the arylamino, aryl, heteroaryl, arylene or heteroarylene of Ar13; the arylene or heteroarylene of Ar14 and Ar15; or the alkyl or aryl of R111 through R113 may be further substituted by one or more substituent(s) selected from a group consisting of deuterium, halogen, (C1-C60)alkyl, (C6-C60)aryl, (C4-C60)heteroaryl, a 5- or 6-membered heterocycloalkyl containing one or more heteroatom(s) selected from N, O and S, (C3-C60)cycloalkyl, tri(C1-C60)alkylsilyl, di(C1-C60)alkyl(C6-C60)arylsilyl, tri(C6-C60)arylsilyl, adamantyl, (C7-C60)bicycloalkyl, (C2-C60)alkenyl, (C2-C60)alkynyl, cyano, (C1-C60)alkylamino, (C6-C60)arylamino, (C6-C60)ar(C1-C60)alkyl, (C6-C60)aryloxy, (C1-C60)alkyloxy, (C6-C60)arylthio, (C1-C60)alkylthio, (C1-C60)alkoxycarbonyl, (C1-C60)alkylcarbonyl, (C6-C60)arylcarbonyl, carboxyl, nitro and hydroxyl.
The electroluminescent layer means the layer where electroluminescence occurs, and it may be a single layer or a multi-layer consisting of two or more layers laminated. When a mixture of host-dopant is used according to the constitution of the present invention, noticeable improvement in luminous efficiency by the electroluminescent host according to the present invention could be confirmed. Those results can be achieved by doping concentration of 0.5 to 10% by weight. The host according to the present invention exhibits higher hole and electron conductivity, and excellent stability of the material as compared to other conventional host materials, and provides improved device life as well as luminous efficiency.
Thus, it can be described that use of the compound represented by one of Chemical Formulas (5) to (7) as an electroluminescent dopant significantly supplements electronic drawback of the organic electroluminescent compounds of Chemical Formula (1) according to the present invention.
The dopant compounds represented by one of Chemical Formulas (5) to (7) can be exemplified by the following compounds, but they are not restricted thereto.
The organic electroluminescent device according to the invention may further comprise one or more compound(s) selected from a group consisting of arylamine compounds and styrylarylamine compounds, as well as the organic electroluminescent compound represented by Chemical Formula (1). Examples of the arylamine or styrylarylamine compounds include the compounds represented by Chemical Formula (8), but they are not restricted thereto:
wherein, Ar21 and Ar22 independently represent (C1-C60)alkyl, (C6-C60)aryl, (C4-C60)heteroaryl, (C6-C60)arylamino, (C1-C60)alkylamino, a 5- or 6-membered heterocycloalkyl containing one or more heteroatom(s) selected from N, O and S, or (C3-C60)cycloalkyl, or Ar21 and Ar22 may be linked via (C3-C60)alkylene or (C3-C60)alkenylene with or without a fused ring to form an alicyclic ring, or a monocyclic or polycyclic aromatic ring;
when f is 1, Ar23 represents (C6-C60)arylamino, (C6-C60)aryl, (C4-C60)heteroaryl, or a substituent represented by one of the following structural formulas:
when f is 2, Ar23 represents (C6-C60)arylene, (C4-C60)heteroarylene, or a substituent represented by one of the following structural formulas:
wherein Ar24 and Ar25 independently represent (C6-C60)arylene or (C4-C60)heteroarylene;
R121, R122 and R123 independently represent hydrogen, deuterium, (C1-C60)alkyl or (C6-C60)aryl;
g is an integer from 1 to 4, h is an integer of 0 or 1; and
the alkyl, aryl, heteroaryl, arylamino, alkylamino, cycloalkyl or heterocycloalkyl of Ar21 and Ar22; the arylamino, aryl, heteroaryl, arylene or heteroarylene of Ar23; the arylene or heteroarylene of Ar24 and Ar25; or the alkyl or aryl of R121 through R123 may be further substituted by one or more substituent(s) selected from a group consisting of deuterium, halogen, (C1-C60)alkyl, (C6-C60)aryl, (C4-C60)heteroaryl, a 5- or 6-membered heterocycloalkyl containing one or more heteroatom(s) selected from N, O and S, (C3-C60)cycloalkyl, tri(C1-C60)alkylsilyl, di(C1-C60)alkyl(C6-C60)arylsilyl, tri(C6-C60)arylsilyl, adamantyl, (C7-C60)bicycloalkyl, (C2-C60)alkenyl, (C2-C60)alkynyl, cyano, (C1-C60)alkylamino, (C6-C60)arylamino, (C6-C60)ar(C1-C60)alkyl, (C6-C60)aryloxy, (C1-C60)alkyloxy, (C6-C60)arylthio, (C1-C60)alkylthio, (C1-C60)alkoxycarbonyl, (C1-C60)alkylcarbonyl, (C6-C60)arylcarbonyl, carboxyl, nitro and hydroxyl.
The arylamine compounds and styrylarylamine compounds may be more specifically exemplified by the following compounds, but they are not restricted thereto.
In an organic electroluminescent device according to the present invention, the organic layer may further comprise one or more metal(s) selected from a group consisting of organic metals of Group 1, Group 2, 4th period and 5th period transition metals, lanthanide metals and d-transition elements, as well as the organic electroluminescent compound represented by Chemical Formula (1). The organic layer may comprise a charge generating layer in addition to the electroluminescent layer.
The present invention can realize an organic electroluminescent device having a pixel structure of independent light-emitting mode, which comprises an organic electroluminescent device containing the compound of Chemical Formula (1) as a sub-pixel and one or more sub-pixel(s) comprising one or more metallic compound(s) selected from a group consisting of Ir, Pt, Pd, Rh, Re, Os, Tl, Pb, Bi, In, Sn, Sb, Te, Au and Ag, patterned in parallel at the same time.
Further, the organic electroluminescent device is an organic light-emitting display which further comprises one or more compound(s) selected from compounds having electroluminescent peak of wavelength of not less than 590 nm, as well as said organic electroluminescent compound in the organic layer. Those compounds can be exemplified by the compounds represented by one of Chemical Formulas (9) to (13), but they are not restricted thereto.
M1L3L4L5 Chemical Formula 9
In Chemical Formula (9), M1 is selected from metals of Group 7, 8, 9, 10, 11, 13, 14, 15 and 16 in the Periodic Table of Elements, and ligands L3, L4 and L5 are independently selected from the following structures:
wherein, R201 through R203 independently represent hydrogen, deuterium, (C1-C60)alkyl with or without halogen substituent(s), (C6-C60)aryl with or without (C1-C60)alkyl substituent(s), or halogen;
R204 through R219 independently represent hydrogen, deuterium, (C1-C60)alkyl, (C1-C30)alkoxy, (C3-C60)cycloalkyl, (C2-C30)alkenyl, (C6-C60)aryl, mono or di(C1-C30)alkylamino, mono or di(C6-30)arylamino, SF5, tri(C1-C30)alkylsilyl, di(C1-C30)alkyl(C6-C30)arylsilyl, tri(C6-C30)arylsilyl, cyano or halogen, and the alkyl, cycloalkyl, alkenyl or aryl of R204 through R219 may be further substituted by one or more substituent(s) selected from deuterium, (C1-C60)alkyl, (C6-C60)aryl and halogen;
R220 through R223 independently represent hydrogen, deuterium, (C1-C60)alkyl with or without halogen substituent(s), (C6-C60)aryl with or without (C1-C60)alkyl substituent(s);
R224 and R225 independently represent hydrogen, deuterium, (C1-C60)alkyl, (C6-C60)aryl or halogen, or R224 and R225 may be linked via (C3-C12)alkylene or (C3-C12)alkenylene with or without a fused ring to form an alicyclic ring, or a monocyclic or polycyclic aromatic ring; and the alkyl or aryl of R224 and R225, or the alicyclic ring, or the monocyclic or polycyclic aromatic ring formed therefrom via (C3-C12)alkylene or (C3-C12)alkenylene with or without a fused ring may be further substituted by one or more substituent(s) selected from deuterium, (C1-C60)alkyl with or without halogen substituent(s), (C1-C30)alkoxy, halogen, tri(C1-C30)alkylsilyl, tri(C6-C30)arylsilyl and (C6-C60)aryl;
R226 represents (C1-C60)alkyl, (C6-C60)aryl, (C5-C60)heteroaryl or halogen;
R227 through R229 independently represent hydrogen, deuterium, (C1-C60)alkyl, (C6-C60)aryl or halogen, and the alkyl or aryl of R226 through R229 may be further substituted by deuterium, halogen or (C1-C60)alkyl; and
Q represents
and R231 through R242 independently represent hydrogen, deuterium, (C1-C60)alkyl with or without halogen substituent(s), (C1-C30)alkoxy, halogen, (C6-C60)aryl, cyano or (C5-C60)cycloalkyl, or each of R231 through R242 may be linked to an adjacent substituent via alkylene or alkenylene to form a (C5-C7) spiro-ring or (C5-C9) fused ring, or each of them may be linked to R207 or R208 via alkylene or alkenylene to form a (C5-C7) fused ring.
In Chemical Formula (10), R301 through R304 independently represent (C1-C60)alkyl or (C6-C60)aryl, or each of them may be linked to an adjacent substituent via (C3-C60)alkylene or (C3-C60)alkenylene with or without a fused ring to form an alicyclic ring, or a monocyclic or polycyclic aromatic ring; and the alkyl or aryl of R301 through R304, or the alicyclic ring, or the monocyclic or polycyclic aromatic ring formed therefrom by linkage via (C3-C60)alkylene or (C3-C60)alkenylene with or without a fused ring may be further substituted by one or more substituent(s) selected from (C1-C60)alkyl with or without halogen substituent(s), (C1-C60)alkoxy, halogen, tri(C1-C60)alkylsilyl, tri(C6-C60)arylsilyl and (C6-C60)aryl.
In Chemical Formula (13), the ligands, L4 and L5 are independently selected from the following structures:
M2 is a bivalent or trivalent metal;
i is 0 when M2 is a bivalent metal, while i is 1 when M2 is a trivalent metal;
T represents (C6-C60)aryloxy or tri(C6-C60)arylsilyl, and the aryloxy and triarylsilyl of T may be further substituted by (C1-C60)alkyl or (C6-C60)aryl;
J represents O, S or Se;
ring A represents oxazole, thiazole, imidazole, oxadiazole, thiadiazole, benzoxazole, benzothiazole, benzimidazole, pyridine or quinoline;
ring B represents pyridine or quinoline, and ring B may be further substituted by deuterium, (C1-C60)alkyl, or phenyl or naphthyl with or without (C1-C60)alkyl substituent(s);
R401 through R404 independently represent hydrogen, deuterium, (C1-C60)alkyl, halogen, tri(C1-C60)alkylsilyl, tri(C6-C60)arylsilyl or (C6-C60)aryl, or each of them may be linked to an adjacent substituent via (C3-C60)alkylene or (C3-C60)alkenylene to form a fused ring, and the pyridine or quinoline may form a chemical bond with R401 to form a fused ring;
ring A or the aryl group of R401 through R404 may be further substituted by deuterium, (C1-C60)alkyl, halogen, (C1-C60)alkyl with halogen substituent(s), phenyl, naphthyl, tri(C1-C60)alkylsilyl, tri(C6-C60)arylsilyl or amino group.
The compounds having electroluminescent peak of wavelength of not less than 590 nm can be exemplified by the following compounds, but they are not restricted thereto.
In an organic electroluminescent device according to the present invention, it is preferable to place one or more layer(s) (here-in-below, referred to as the “surface layer”) selected from chalcogenide layers, metal halide layers and metal oxide layers, on the inner surface of at least one side of the pair of electrodes. Specifically, it is preferable to arrange a chalcogenide layer of silicon and aluminum metal (including oxides) on the anode surface of the EL medium layer, and a metal halide layer or a metal oxide layer on the cathode surface of the EL medium layer. As the result, stability in operation can be obtained.
Examples of chalcogenides preferably include SiOx (1≦x≦2), AlOx (1≦x≦1.5), SiON, SiAlON, or the like. Examples of metal halides preferably include LiF, MgF2, CaF2, fluorides of rare earth metal, or the like. Examples of metal oxides preferably include Cs2O, Li2O, MgO, SrO, BaO, CaO, or the like.
In an organic electroluminescent device according to the present invention, it is also preferable to arrange, on at least one surface of the pair of electrodes thus manufactured, a mixed region of electron transport compound and a reductive dopant, or a mixed region of a hole transport compound with an oxidative dopant. Accordingly, the electron transport compound is reduced to an anion, so that injection and transportation of electrons from the mixed region to an EL medium are facilitated. In addition, since the hole transport compound is oxidized to form a cation, injection and transportation of holes from the mixed region to an EL medium are facilitated. Preferable oxidative dopants include various Lewis acids and acceptor compounds. Preferable reductive dopants include alkali metals, alkali metal compounds, alkaline earth metals, rare-earth metals, and mixtures thereof.
The organic compounds according to the invention, having excellent luminous efficiency and life property of material, can be advantageously employed for manufacturing OLED's having very good operation life.
Best Mode
The present invention is further described with respect to the representative compounds of the invention, by describing the organic electroluminescent compounds, the processes for preparing the same, and luminescent properties of the device manufactured therefrom in the Examples below, which are provided for illustration of the embodiments only but are not intended to limit the scope of the invention by any means.
Preparation of Compound (1)
Preparation of Compound (A)
Under nitrogen atmosphere, a 50 mL round-bottomed flask was charged with 3-bromopyridine (96 μL, 1 mmol) and diethyl ether (10 mL), and the mixture was stirred. After chilling to −78° C., butyllithium (2.5 mL, 1 mmol, 2.5 M in hexane) was slowly added thereto. The resultant mixture was stirred at −78° C. for 1 hour, and dimethyl phthalate (0.17 mL, 1 mmol) was slowly added at −78° C. After stirring at the same temperature for 2 hours, the temperature was slowly raised to room temperature, and water (5 mL) was added to the reaction mixture to carry out hydrolysis. Organic layers obtained from ether extraction were combined, and dried to remove the solvent. Purification via column chromatography gave Compound (A) (0.14 g, 56%) as solid product.
Preparation of Compound (B)
Under nitrogen atmosphere, a 50 mL round-bottomed flask was charged with Compound (A) (0.11 g, 0.44 mmol) and THF (5 mL), and the mixture was stirred. At 0° C., LTMP solution (10 mL) was added thereto, and the resultant mixture was stirred at the same temperature for 2 hours. Then, the temperature was slowly raised to room temperature, and water (5 mL) was added to the mixture to carry out hydrolysis. Organic layers obtained from ethyl acetate extraction were combined, and dried to remove the solvent. Purification via column chromatography gave Compound (B) (41 mg, 44%) as solid product.
Preparation of Compound (C)
In a flask, CuSO4.5H2O (2.4 g, 9.56 mmol) was dissolved in water (30 mL), and Zn (11.7 g, 179.25 mmol) was added thereto. After sequentially adding aqueous 2M NaOH solution (50 mL), toluene (50 mL) and Compound (B) (5 g, 23.9 mmol), the mixture was stirred for about 10 minutes, and then stirred under reflux at 110° C. for one day. When the reaction was completed, the reaction mixture was extracted with water (200 mL) and dichloromethane (150 mL), and the extract was dried under reduced pressure. Purification via column chromatography gave Compound (C) (3.9 g, 21.8 mmol).
Preparation of Compound (D)
Compound (C) (3.9 g, 21.8 mmol) and N-bromosuccinimide (4.7 g, 26.2 mmol) were dissolved in dichloromethane (100 mL) under nitrogen atmosphere, and stirred at 25° C. for one day. Then, the reaction was quenched by adding distilled water (200 mL), and the mixture was extracted with dichloromethane (250 mL). After drying the extract under reduced pressure, the residue was purified via column chromatography to obtain Compound (D) (4.8 g, 18.45 mmol).
Preparation of Compound (E)
Compound (D) (4.8 g, 18.45 mmol), phenylboronic acid (2.4 g, 22.14 mmol) and tetrakispalladium (0) triphenylphosphine (Pd(PPh3)4) (2.8 g, 1.8 mmol) were dissolved in toluene (150 mL) and ethanol (80 mL), and aqueous 2 M sodium carbonate solution (80 mL) was added thereto. After stirring under reflux at 120° C. for 4 hours, the temperature was lowered to 25° C. Then, the reaction was quenched by adding distilled water (200 mL), and the mixture was extracted with ethyl acetate (150 mL). After drying the extract under reduced pressure, the residue was purified via column chromatography to obtain Compound (E) (4.3 g, 16.84 mmol).
Preparation of Compound (F)
Compound (E) (4.3 g, 16.84 mmol) and N-bromosuccinimide (3.6 g, 20.20 mmol) were dissolved in dichloromethane (100 mL) under nitrogen atmosphere, and the solution was stirred at 25° C. for one day. Then, the reaction was quenched by adding distilled water (200 mL), and the mixture was extracted with dichloromethane (250 mL). After drying under reduced pressure, the residue was purified via column chromatography to obtain Compound (F) (4.7 g, 14.06 mmol).
Preparation of Compound (1)
A reaction vessel was charged with Compound (F) (4.7 g, 14.06 mmol), phenol (4.0 g, 42.18 mmol) and potassium hydroxide (2.4 g, 42.18 mmol), and the mixture was stirred with heating at 230° C. for 6 hours. When the reaction was completed, the mixture was cooled to room temperature. After adding sodium hydroxide and toluene, the resultant mixture was extracted. Toluene was removed by vacuum sublimation, and the filtrate was purified via column chromatography to obtain Compound (I) (2.73 g, 7.9 mmol).
According to the procedure of Preparation Example 1, organic electroluminescent compounds (Compounds 1 to 657) were prepared, and the 1H NMR and MS/FAB data are shown in Table 1.
1H NMR(CDCl3, 200 MHz)
An OLED device was manufactured by using an electroluminescent material according to the invention.
First, a transparent electrode ITO thin film (15Ω/□) (2) prepared from glass for OLED (produced by Samsung Corning) (1) was subjected to ultrasonic washing with trichloroethylene, acetone, ethanol and distilled water, sequentially, and stored in isopropanol before use.
Then, an ITO substrate was equipped in a substrate folder of a vacuum vapor-deposit device, and 4,4′,4″-tris(N,N-(2-naphthyl)-phenylamino)triphenylamine (2-TNATA) was placed in a cell of the vacuum vapor-deposit device, which was then ventilated up to 10−6 torr of vacuum in the chamber. Electric current was applied to the cell to evaporate 2-TNATA, thereby providing vapor-deposit of a hole injecting layer (3) having 60 nm of thickness on the ITO substrate.
Then, to another cell of the vacuum vapor-deposit device, charged was N,N′-bis(α-naphthyl)-N,N′-diphenyl-4,4′-diamine (NPB) (of which the structure is shown below), and electric current was applied to the cell to evaporate NPB, thereby providing vapor-deposit of a hole transport layer (4) of 20 nm of thickness on the hole injecting layer.
After forming the hole injecting layer and the hole transport layer, an electroluminescent layer was vapor-deposited according to the following procedure. To one cell of a vacuum vapor-deposit device, charged was a compound according to the present invention (e.g. Compound 5) as an electroluminescent host material, while DSA-Ph (of which the structure is shown below) was charged to another cell. The two cells were simultaneously heated to carry out vapor-deposition of DSA-Ph at 2 to 5% by weight of vapor-deposition rate, to vapor-deposit an electroluminescent layer (5) having 30 nm of thickness on the hole transport layer.
Then, tris(8-hydroxyquinoline)aluminum (III) (Alq) was vapor-deposited as an electron transport layer (6) in a thickness of 20 nm, and then lithium quinolate (Liq) was vapor-deposited as an electron injecting layer (7) in a thickness of 1 to 2 nm. Thereafter, an Al cathode (8) was vapor-deposited in a thickness of 150 nm by using another vacuum vapor-deposit device to manufacture an OLED.
Each compound was employed as electroluminescent material for an OLED after purifying via vacuum sublimation at 10−6 torr.
After forming a hole injecting layer (3) and hole transport layer (4) according to the same procedure as described in Example 1, dinaphthylanthracene (DNA) was charged to another cell of said vacuum vapor-deposit device as electroluminescent host material, and DSA-Ph (as in Example 1) was charged to still another cell. At a vapor-deposition rate of 100:3, an electroluminescent layer (5) having 30 nm of thickness was vapor-deposited on the hole transport layer.
Then, an electron transport layer (6) and electron injecting layer (7) were vapor-deposited according to the same procedure as in Example 1, and an Al cathode (8) was vapor-deposited thereon with a thickness of 150 nm by using another vacuum vapor-deposit device to manufacture an OLED.
After forming a hole injecting layer and a hole transport layer according to the same procedure as described in Example 1, a compound according to the present invention (e.g. Compound 5) was charged to one cell of said vacuum vapor-deposit device as electroluminescent material, and Compound (E) (of which the structure is shown below) was charged to another cell. Then the two materials were evaporated at different rates to carry out doping at a concentration of 2 to 5% by weight on the basis of the host, thereby providing an electroluminescent layer having 30 nm of thickness vapor-deposited on the hole transport layer.
Then, an electron transport layer and electron injecting layer were vapor-deposited according to the same procedure as in Example 1, and an Al cathode was vapor-deposited thereon with a thickness of 150 nm by using another vacuum vapor-deposit device to manufacture an OLED.
After forming a hole injecting layer and a hole transport layer according to the same procedure as described in Example 1, tris(8-hydroxyquinoline)-aluminum (III) (Alq) was charged to another cell of said vacuum vapor-deposit device as electroluminescent host material, and Coumarin 545T (C545T) (of which the structure is shown below) was charged to still another cell. Then the two materials were evaporated at different rates to carry out doping, and thus providing an electroluminescent layer having 30 nm of thickness vapor-deposited on the hole transport layer. The doping concentration was preferably from 1 to 3% by weight on the basis of Alq.
Then, an electron transport layer and electron injecting layer were vapor-deposited according to the same procedure as Example 1, and an Al cathode was vapor-deposited thereon with a thickness of 150 nm by using another vacuum vapor-deposit device to manufacture an OLED.
The luminous efficiencies of the OLED's comprising the organic electroluminescent compounds according to the present invention (Examples 1 and 2) or conventional EL compound (Comparative Example 1 and 2) were measured at 5,000 cd/m2, respectively, and the results are shown in Table 2.
As can be seen from Table 2, when the material according to the invention was applied to a blue electroluminescent device, commonly with DSA-Ph doping to the organic electroluminescent compound of the invention, the device showed comparable luminous efficiency but far higher color purity as compared to the device employing DNA as conventional electroluminescent material according to Comparative Example 1.
Furthermore, it is found from Table 2 that, when the material according to the invention (Compound 257 as organic electroluminescent compound) was applied to a green electroluminescent device, with doping of Compound (E) at a concentration of 3.0 wt %, the device showed more than twice of luminous efficiency as compared to the conventional electroluminescent device employing Alq:C545T (Comparative Example 2).
Accordingly, the organic electroluminescent compounds according to the present invention can be used as blue or green electroluminescent material of high efficiency. Moreover, the device, to which the host material according to the invention was applied, showed noticeable improvement in view of color purity. The improvement in both color purity and luminous efficiency proves that the materials of the present invention have excellent properties.
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