Patent Publication Number: US-2021167293-A1

Title: Polycyclic aromatic compounds and organic electroluminescent devices using the same

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to polycyclic aromatic compounds and highly efficient and long-lasting organic electroluminescent devices with greatly improved luminous efficiency using the same. 
     2. Description of the Related Art 
     Organic electroluminescent devices are self-luminous devices in which electrons injected from an electron injecting electrode (cathode) recombine with holes injected from a hole injecting electrode (anode) in a light emitting layer to form excitons, which emit light while releasing energy. Such organic electroluminescent devices have the advantages of low driving voltage, high luminance, large viewing angle, and short response time and can be applied to full-color light emitting flat panel displays. Due to these advantages, organic electroluminescent devices have received attention as next-generation light sources. 
     The above characteristics of organic electroluminescent devices are achieved by structural optimization of organic layers of the devices and are supported by stable and efficient materials for the organic layers, such as hole injecting materials, hole transport materials, light emitting materials, electron transport materials, electron injecting materials, and electron blocking materials. However, more research still needs to be done to develop structurally optimized structures of organic layers for organic electroluminescent devices and stable and efficient materials for organic layers of organic electroluminescent devices. 
     Thus, there is a continued need to develop structures of organic electroluminescent devices optimized to improve their luminescent properties and new materials capable of supporting the optimized structures of organic electroluminescent devices. 
     SUMMARY OF THE INVENTION 
     Therefore, the present invention intends to provide organic electroluminescent compounds that are employed in organic layers of organic electroluminescent devices, achieving high efficiency and long lifetime of the devices. The present invention also intends to provide organic electroluminescent devices including the organic electroluminescent compounds. 
     One aspect of the present invention provides an organic electroluminescent compound represented by Formula A-5 or A-7: 
     
       
         
         
             
             
         
       
     
     A description will be given concerning more detailed structures of the compounds of Formulae A-5 and A-7, the definitions of substituents Y 1 , Y 2 , X, and Z in the compounds of Formulae A-5 and A-7, and specific examples of polycyclic aromatic compounds that can be represented by Formulae A-5 and A-7. 
     A further aspect of the present invention provides an organic electroluminescent device including a first electrode, a second electrode opposite to the first electrode, and one or more organic layers interposed between the first and second electrodes wherein at least one of the organic layers includes the polycyclic aromatic compound represented by Formula A-5 or A-7. 
     The polycyclic aromatic compound of the present invention is employed in at least one of the organic layers of the organic electroluminescent device, achieving high efficiency and long lifetime of the device. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will now be described in more detail. 
     The present invention is directed to a polycyclic aromatic compound represented by Formula A-5 or A-7: 
     
       
         
         
             
             
         
       
     
     wherein X is selected from B, P, and P═O, 
     the moieties Y 1  and Y 2  are identical to or different from each other and are each independently selected from NR 1 , CR 2 R 3 , O, S, Se, and SiR 4 R 5 , with the proviso that the two Y 1  moieties are not simultaneously NR 1  (wherein R 1  to R 5  are identical to or different from each other and are each independently selected from hydrogen, deuterium, substituted or unsubstituted C 1 -C 30  alkyl, substituted or unsubstituted C 6 -C 50  aryl, substituted or unsubstituted C 3 -C 30  cycloalkyl, substituted or unsubstituted C 2 -C 50  heteroaryl, substituted or unsubstituted C 1 -C 30  alkoxy, substituted or unsubstituted C 6 -C 30  aryloxy, substituted or unsubstituted C 1 -C 30  alkylthioxy, substituted or unsubstituted C 5 -C 30  arylthioxy, substituted or unsubstituted C 1 -C 30  alkylamine, substituted or unsubstituted C 5 -C 30  arylamine, substituted or unsubstituted C 1 -C 30  alkylsilyl, substituted or unsubstituted C 5 -C 30  arylsilyl, substituted or unsubstituted C 3 -C 20  mixed aliphatic-aromatic cyclic group, nitro, cyano, and halogen, with the proviso that R 2  and R 3  are optionally linked to each other to form an alicyclic or aromatic monocyclic or polycyclic ring and R 4  and R 5  are optionally linked to each other to form an alicyclic or aromatic monocyclic or polycyclic ring), and 
     the moieties Z are identical to or different from each other and are each independently CR or N (wherein R is selected from hydrogen, deuterium, substituted or unsubstituted C 1 -C 30  alkyl, substituted or unsubstituted C 6 -C 50  aryl, substituted or unsubstituted C 3 -C 30  cycloalkyl, substituted or unsubstituted C 2 -C 50  heteroaryl, substituted or unsubstituted C 1 -C 30  alkoxy, substituted or unsubstituted C 6 -C 30  aryloxy, substituted or unsubstituted C 1 -C 30  alkylthioxy, substituted or unsubstituted C 5 -C 30  arylthioxy, substituted or unsubstituted C 1 -C 30  alkylamine, substituted or unsubstituted C 5 -C 30  arylamine, substituted or unsubstituted C 1 -C 30  alkylsilyl, substituted or unsubstituted C 5 -C 30  arylsilyl, substituted or unsubstituted C 3 -C 20  mixed aliphatic-aromatic cyclic group, nitro, cyano, and halogen), with the proviso that R 1  is optionally linked to R of the adjacent Z moiety through O, S, CR 6 R 7  or a single bond to form an alicyclic or aromatic monocyclic or polycyclic ring in which some or all of the carbon atoms are optionally substituted with heteroatoms selected from N, S, and O (wherein R 6  and R 7  are each independently selected from hydrogen, deuterium, substituted or unsubstituted C 1 -C 30  alkyl, substituted or unsubstituted C 6 -C 50  aryl, and substituted or unsubstituted C 3 -C 30  cycloalkyl, and substituted or unsubstituted C 2 -C 50  heteroaryl) and with the proviso that the plurality of R groups are optionally bonded to each other to form an alicyclic or aromatic monocyclic or polycyclic ring in which some or all of the carbon atoms are optionally substituted with heteroatoms selected from N, S, and O; or 
     
       
         
         
             
             
         
       
     
     wherein X, Y 1 , Y 2 , and Z are as defined in Formula A-5, with the proviso that the two Y 1  moieties are optionally simultaneously NR 1 . 
     According to a preferred embodiment of the present invention, X in Formula A-5 or A-7 is preferably B. The presence of boron (B) in the structure of the polycyclic aromatic compound ensures high efficiency and long lifetime of an organic electroluminescent device. 
     The polycyclic aromatic compound of Formula A-5 or A-7 can be employed in an organic electroluminescent device, achieving high efficiency and long lifetime of the device. 
     The use of the skeletal structure meets desired requirements of various organic layers of an organic electroluminescent device, achieving high efficiency and long lifetime of the device. 
     As used herein, the term “substituted” in the definition of R, and R 1  to R 5  indicates substitution with one or more substituents selected from the group consisting of deuterium, cyano, halogen, hydroxyl, nitro, C 1 -C 24  alkyl, C 3 -C 24  cycloalkyl, C 1 -C 24  haloalkyl, C 1 -C 24  alkenyl, C 1 -C 24  alkynyl, C 1 -C 24  heteroalkyl, C 1 -C 24  heterocycloalkyl, C 6 -C 24  aryl, C 6 -C 24  arylalkyl, C 2 -C 24  heteroaryl, C 2 -C 24  heteroarylalkyl, C 1 -C 24  alkoxy, C 1 -C 24  alkylamino, C 1 -C 24  arylamino, C 1 -C 24  heteroarylamino, C 1 -C 24  alkylsilyl, C 1 -C 24  arylsilyl, and C 1 -C 24  aryloxy, or a combination thereof. The term “unsubstituted” in the same definition indicates having no substituent. 
     In the “substituted or unsubstituted C 1 -C 10  alkyl”, “substituted or unsubstituted C 6 -C 30  aryl”, etc., the number of carbon atoms in the alkyl or aryl group indicates the number of carbon atoms constituting the unsubstituted alkyl or aryl moiety without considering the number of carbon atoms in the substituent(s). For example, a phenyl group substituted with a butyl group at the para-position corresponds to a C 6  aryl group substituted with a C 4  butyl group. 
     As used herein, the expression “form a ring with an adjacent substituent” means that the corresponding substituent combines with an adjacent substituent to form a substituted or unsubstituted alicyclic or aromatic ring and the term “adjacent substituent” may mean a substituent on an atom directly attached to an atom substituted with the corresponding substituent, a substituent disposed sterically closest to the corresponding substituent or another substituent on an atom substituted with the corresponding substituent. For example, two substituents substituted at the ortho position of a benzene ring or two substituents on the same carbon in an aliphatic ring may be considered “adjacent” to each other. 
     In the present invention, the alkyl groups may be straight or branched. The number of carbon atoms in the alkyl groups is not particularly limited but is preferably from 1 to 20. Specific examples of the alkyl groups include, but are not limited to, methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methylbutyl, 1-ethylbutyl, pentyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, heptyl, n-heptyl, 1-methylhexyl, cyclopentylmethyl, cyclohexylmethyl, octyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, 1-ethylpropyl, 1,1-dimethylpropyl, isohexyl, 4-methylhexyl, and 5-methylhexyl groups. 
     The alkenyl group is intended to include straight and branched ones and may be optionally substituted with one or more other substituents. The alkenyl group may be specifically a vinyl, 1-propenyl, isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 3-methyl-1-butenyl, 1,3-butadienyl, allyl, 1-phenylvinyl-1-yl, 2-phenylvinyl-1-yl, 2,2-diphenylvinyl-1-yl, 2-phenyl-2-(naphthyl-1-yl)vinyl-1-yl, 2,2-bis(diphenyl-1-yl)vinyl-1-yl, stilbenyl or styrenyl group but is not limited thereto. 
     The alkynyl group is intended to include straight and branched ones and may be optionally substituted with one or more other substituents. The alkynyl group may be, for example, ethynyl or 2-propynyl but is not limited thereto. 
     The cycloalkyl group is intended to include monocyclic and polycyclic ones and may be optionally substituted with one or more other substituents. As used herein, the term “polycyclic” means that the cycloalkyl group may be directly attached or fused to one or more other cyclic groups. The other cyclic groups may be cycloalkyl groups and other examples thereof include heterocycloalkyl, aryl, and heteroaryl groups. The cycloalkyl group may be specifically a cyclopropyl, cyclobutyl, cyclopentyl, 3-methylcyclopentyl, 2,3-dimethylcyclopentyl, cyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, 2,3-dimethylcyclohexyl, 3,4,5-trimethylcyclohexyl, 4-tert-butylcyclohexyl, cycloheptyl or cyclooctyl group but is not limited thereto. 
     The heterocycloalkyl group is intended to include monocyclic and polycyclic ones interrupted by a heteroatom such as O, S, Se, N or Si and may be optionally substituted with one or more other substituents. As used herein, the term “polycyclic” means that the heterocycloalkyl group may be directly attached or fused to one or more other cyclic groups. The other cyclic groups may be heterocycloalkyl groups and other examples thereof include cycloalkyl, aryl, and heteroaryl groups. 
     The aryl groups may be monocyclic or polycyclic ones. Examples of the monocyclic aryl groups include, but are not limited to, phenyl, biphenyl, terphenyl, and terphenyl groups. Examples of the polycyclic aryl groups include naphthyl, anthracenyl, phenanthrenyl, pyrenyl, perylenyl, tetracenyl, chrysenyl, fluorenyl, acenaphathcenyl, triphenylene, and fluoranthrene groups but the scope of the present invention is not limited thereto. 
     The heteroaryl groups refer to heterocyclic groups interrupted by one or more heteroatoms. Examples of the heteroaryl groups include, but are not limited to, thiophene, furan, pyrrole, imidazole, triazole, oxazole, oxadiazole, triazole, pyridyl, bipyridyl, pyrimidyl, triazine, triazole, acridyl, pyridazine, pyrazinyl, quinolinyl, quinazoline, quinoxalinyl, phthalazinyl, pyridopyrimidinyl, pyridopyrazinyl, pyrazinopyrazinyl, isoquinoline, indole, carbazole, benzoxazole, benzimidazole, benzothiazole, benzocarbazole, benzothiophene, dibenzothiophene, benzofuranyl, dibenzofuranyl, phenanthroline, thiazolyl, isoxazolyl, oxadiazolyl, thiadiazolyl, benzothiazolyl, and phenothiazinyl groups. 
     As used herein, the term “mixed aliphatic-aromatic cyclic group” refers to a ring structure in which at least one aliphatic ring and at least one aromatic ring are linked and fused together and which is overall non-aromatic. The mixed aliphatic-aromatic polycyclic group may include one or more heteroatoms selected from N, O, P, and S other than carbon atoms. 
     The alkoxy group may be specifically a methoxy, ethoxy, propoxy, isobutyloxy, sec-butyloxy, pentyloxy, iso-amyloxy or hexyloxy group, but is not limited thereto. 
     The silyl group is intended to include alkyl-substituted silyl groups and aryl-substituted silyl groups. Specific examples of such silyl groups include trimethylsilyl, triethylsilyl, triphenylsilyl, trimethoxysilyl, dimethoxyphenylsilyl, diphenylmethylsilyl, diphenylvinylsilyl, methylcyclobutylsilyl, and dimethylfurylsilyl. 
     The amine groups may be, for example, —NH 2 , alkylamine groups, and arylamine groups. The arylamine groups are aryl-substituted amine groups and the alkylamine groups are alkyl-substituted amine groups. Examples of the arylamine groups include substituted or unsubstituted monoarylamine groups, substituted or unsubstituted diarylamine groups, and substituted or unsubstituted triarylamine groups. The aryl groups in the arylamine groups may be monocyclic or polycyclic ones. The arylamine groups may include two or more aryl groups. In this case, the aryl groups may be monocyclic aryl groups or polycyclic aryl groups. Alternatively, the aryl groups may consist of a monocyclic aryl group and a polycyclic aryl group. The aryl groups in the arylamine groups may be selected from those exemplified above. 
     The aryl groups in the aryloxy group and the arylthioxy group are the same as those described above. Specific examples of the aryloxy groups include, but are not limited to, phenoxy, p-tolyloxy, m-tolyloxy, 3,5-dimethylphenoxy, 2,4,6-trimethylphenoxy, p-tert-butylphenoxy, 3-biphenyloxy, 4-biphenyloxy, 1-naphthyloxy, 2-naphthyloxy, 4-methyl-1-naphthyloxy, 5-methyl-2-naphthyloxy, 1-anthryloxy, 2-anthryloxy, 9-anthryloxy, 1-phenanthryloxy, 3-phenanthryloxy, and 9-phenanthryloxy groups. The arylthioxy group may be, for example, a phenylthioxy, 2-methylphenylthioxy or 4-tert-butylphenylthioxy group but is not limited thereto. 
     The halogen group may be, for example, fluorine, chlorine, bromine or iodine. 
     More specifically, the polycyclic aromatic compound represented by Formula A-7 may be selected from the following compounds: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     More specifically, the polycyclic aromatic compound represented by Formula A-5 may be selected from the following compounds: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     The specific examples of the substituents defined above can be found in the compounds of Formulae 1 to 136 but are not intended to limit the scope of the compound represented by Formula A-5 or A-7. 
     The introduction of substituents, including B, P or P═O, to form polycyclic aromatic structures allows the organic light emitting materials to have inherent characteristics of the substituents. For example, the introduced substituents may be those that are typically used in materials for hole injecting layers, hole transport layers, light emitting layers, electron transport layers, electron injecting layers, electron blocking layers, and hole blocking layers of organic electroluminescent devices. This introduction meets the requirements of the organic layers and enables the fabrication of highly efficient organic electroluminescent devices. 
     A further aspect of the present invention is directed to an organic electroluminescent device including a first electrode, a second electrode, and one or more organic layers interposed between the first and second electrodes wherein at least one of the organic layers includes the organic electroluminescent compound represented by Formula A-1 or A-2 and optionally another organic electroluminescent compound represented by Formula A-5 or A-7. 
     That is, according to one embodiment of the present invention, the organic electroluminescent device has a structure in which one or more organic layers are arranged between a first electrode and a second electrode. The organic electroluminescent device of the present invention may be fabricated by a suitable method known in the art using suitable materials known in the art, except that the organic electroluminescent compound of Formula A-5 or A-7 is used to form the corresponding organic layer. 
     The organic layers of the organic electroluminescent device according to the present invention may form a monolayer structure. Alternatively, the organic layers may have a multilayer laminate structure. For example, the structure of the organic layers may include a hole injecting layer, a hole transport layer, a hole blocking layer, a light emitting layer, an electron blocking layer, an electron transport layer, and an electron injecting layer, but is not limited thereto. The number of the organic layers is not limited and may be increased or decreased. Preferred structures of the organic layers of the organic electroluminescent device according to the present invention will be explained in more detail in the Examples section that follows. 
     A more detailed description will be given concerning exemplary embodiments of the organic electroluminescent device according to the present invention. 
     The organic electroluminescent device of the present invention includes an anode, a hole transport layer, a light emitting layer, an electron transport layer, and a cathode. The organic electroluminescent device of the present invention may optionally further include a hole injecting layer between the anode and the hole transport layer and an electron injecting layer between the electron transport layer and the cathode. If necessary, the organic electroluminescent device of the present invention may further include one or two intermediate layers such as a hole blocking layer or an electron blocking layer. The organic electroluminescent device of the present invention may further include one or more organic layers such as a capping layer that have various functions depending on the desired characteristics of the device. 
     The light emitting layer of the organic electroluminescent device according to the present invention includes, as a host compound, an anthracene derivative represented by Formula C: 
     
       
         
         
             
             
         
       
     
     wherein R 21  to R 28  are identical to or different from each other and are as defined for R 1  to R 5  in Formula A-5 or A-7, Ar 9  and Ar 10  are identical to or different from each other and are each independently selected from hydrogen, deuterium, substituted or unsubstituted C 1 -C 30  alkyl, substituted or unsubstituted C 6 -C 50  aryl, substituted or unsubstituted C 2 -C 30  alkenyl, substituted or unsubstituted C 2 -C 20  alkynyl, substituted or unsubstituted C 3 -C 30  cycloalkyl, substituted or unsubstituted C 5 -C 30  cycloalkenyl, substituted or unsubstituted C 2 -C 50  heteroaryl, substituted or unsubstituted C 2 -C 30  heterocycloalkyl, substituted or unsubstituted C 1 -C 30  alkoxy, substituted or unsubstituted C 6 -C 30  aryloxy, substituted or unsubstituted C 1 -C 30  alkylthioxy, substituted or unsubstituted C 6 -C 30  arylthioxy, substituted or unsubstituted C 1 -C 30  alkylamine, substituted or unsubstituted C 6 -C 30  arylamine, substituted or unsubstituted C 1 -C 30  alkylsilyl, and substituted or unsubstituted C 6 -C 30  arylsilyl, L 13  is a single bond or is selected from substituted or unsubstituted C 6 -C 20  arylene and substituted or unsubstituted C 2 -C 20  heteroarylene, preferably a single bond or substituted or unsubstituted C 6 -C 20  arylene, and k is an integer from 1 to 3, provided that when k is 2 or more, the linkers L 13  are identical to or different from each other. 
     Ar 9  in Formula C is represented by Formula C-1: 
     
       
         
         
             
             
         
       
     
     wherein R 31  to R 35  are identical to or different from each other and are as defined for R 1  to R 5  in Formula A-5 or A-7, and each of R 31  to R 35  is optionally bonded to an adjacent substituent to form a saturated or unsaturated ring. 
     The compound of Formula C employed in the organic electroluminescent device of the present invention may be specifically selected from the compounds of Formulae C1 to C48: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     The organic electroluminescent device of the present invention may further include one or more organic layers, for example, a hole transport layer and an electron blocking layer, each of which may include a compound represented by Formula D: 
     
       
         
         
             
             
         
       
     
     wherein R 41  to R 43  are identical to or different from each other and are each independently selected from hydrogen, deuterium, substituted or unsubstituted C 1 -C 20  alkyl, substituted or unsubstituted C 6 -C 50  aryl, substituted or unsubstituted C 7 -C 50  arylalkyl, substituted or unsubstituted C 3 -C 30  cycloalkyl, substituted or unsubstituted C 1 -C 30  alkylsilyl, substituted or unsubstituted C 6 -C 30  arylsilyl, and halogen, L 31  to L 34  are identical to or different from each other and are each independently single bonds or selected from substituted or unsubstituted C 6 -C 50  arylene and substituted or unsubstituted C 2 -C 50  heteroarylene, Ar 31  to Ar 34  are identical to or different from each other and are each independently selected from substituted or unsubstituted C 6 -C 50  aryl and substituted or unsubstituted C 2 -C 50  heteroaryl, n is an integer from 0 to 4, provided that when n is 2 or greater, the aromatic rings containing R 43  are identical to or different from each other, m 1  to m 3  are integers from 0 to 4, provided that when both m 1  and m 3  are 2 or more, the R 41 , R 42 , and R 43  groups are identical to or different from each other, and hydrogen or deuterium atoms are bonded to the carbon atoms of the aromatic rings to which R 41  to R 43  are not attached. 
     In Formula D, at least one of Ar 31  to Ar 34  is represented by Formula E: 
     
       
         
         
             
             
         
       
     
     wherein R 51  to R 54  are identical to or different from each other and are each independently selected from hydrogen, deuterium, substituted or unsubstituted C 1 -C 30  alkyl, substituted or unsubstituted C 6 -C 50  aryl, substituted or unsubstituted C 2 -C 30  alkenyl, substituted or unsubstituted C 2 -C 20  alkynyl, substituted or unsubstituted C 3 -C 30  cycloalkyl, substituted or unsubstituted C 5 -C 30  cycloalkenyl, substituted or unsubstituted C 2 -C 50  heteroaryl, substituted or unsubstituted C 2 -C 30  heterocycloalkyl, substituted or unsubstituted C 1 -C 30  alkoxy, substituted or unsubstituted C 6 -C 30  aryloxy, substituted or unsubstituted C 1 -C 30  alkylthioxy, substituted or unsubstituted C 5 -C 30  arylthioxy, substituted or unsubstituted C 1 -C 30  alkylamine, substituted or unsubstituted C 5 -C 30  arylamine, substituted or unsubstituted C 1 -C 30  alkylsilyl, substituted or unsubstituted C 5 -C 30  arylsilyl, nitro, cyano, and halogen, which are optionally linked to each other to form a ring, Y is a carbon or nitrogen atom, Z is a carbon, oxygen, sulfur or nitrogen atom, Ar 35  to Ar 37  are identical to or different from each other and are each independently selected from substituted or unsubstituted C 5 -C 50  aryl and substituted or unsubstituted C 3 -C 50  heteroaryl, provided that when Z is an oxygen or sulfur atom, Ar 37  is nothing, provided that when Y and Z are nitrogen atoms, only one of Ar 35 , Ar 36 , and Ar 37  is present, provided that when Y is a nitrogen atom and Z is a carbon atom, Ar 36  is nothing, with the proviso that one of R 51  to R 54  and Ar 35  to Ar 37  is a single bond linked to one of the linkers L 31  to L 34  in Formula D. 
     The compound of Formula D employed in the organic electroluminescent device of the present invention may be specifically selected from the compounds of Formulae D1 to D79: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     The compound of Formula D employed in the organic electroluminescent device of the present invention may be specifically selected from the compounds of Formulae D101 to D145: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     The organic electroluminescent device of the present invention may further include one or more organic layers, for example, a hole transport layer and an electron blocking layer, each of which may include a compound represented by Formula F: 
     
       
         
         
             
             
         
       
     
     wherein R 61  to R 63  are identical to or different from each other and are each independently selected from hydrogen, deuterium, substituted or unsubstituted C 1 -C 30  alkyl, substituted or unsubstituted C 6 -C 50  aryl, substituted or unsubstituted C 2 -C 30  alkenyl, substituted or unsubstituted C 2 -C 20  alkynyl, substituted or unsubstituted C 3 -C 30  cycloalkyl, substituted or unsubstituted C 5 -C 30  cycloalkenyl, substituted or unsubstituted C 2 -C 50  heteroaryl, substituted or unsubstituted C 2 -C 30  heterocycloalkyl, substituted or unsubstituted C 1 -C 30  alkoxy, substituted or unsubstituted C 6 -C 30  aryloxy, substituted or unsubstituted C 1 -C 30  alkylthioxy, substituted or unsubstituted C 6 -C 30  arylthioxy, substituted or unsubstituted C 1 -C 30  alkylamine, substituted or unsubstituted C 6 -C 30  arylamine, substituted or unsubstituted C 1 -C 30  alkylsilyl, substituted or unsubstituted C 6 -C 30  arylsilyl, substituted or unsubstituted C 1 -C 30  alkylgermanium, substituted or unsubstituted C 1 -C 30  arylgermanium, cyano, nitro, and halogen, and Ar 51  to Ar 54  are identical to or different from each other and are each independently substituted or unsubstituted C 6 -C 40  aryl or substituted or unsubstituted C 2 -C 30  heteroaryl. 
     The compound of Formula F employed in the organic electroluminescent device of the present invention may be specifically selected from the compounds of Formulae F1 to F33: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     A specific structure of the organic electroluminescent device according to the present invention, a method for fabricating the device, and materials for the organic layers will be described below. 
     First, a material for the anode is coated on the substrate to form the anode. The substrate may be any of those used in general electroluminescent devices. The substrate is preferably an organic substrate or a transparent plastic substrate that is excellent in transparency, surface smoothness, ease of handling, and waterproofness. A highly transparent and conductive metal oxide, such as indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO 2 ) or zinc oxide (ZnO), is used as the anode material. 
     A material for the hole injecting layer is coated on the anode by vacuum thermal evaporation or spin coating to form the hole injecting layer. Then, a material for the hole transport layer is coated on the hole injecting layer by vacuum thermal evaporation or spin coating to form the hole transport layer. 
     The material for the hole injecting layer is not specially limited so long as it is usually used in the art. Specific examples of such materials include 4,4′,4″-tris(2-naphthyl(phenyl)amino)triphenylamine (2-TNATA), N,N′-di(1-naphthyl)-N,N′-diphenylbenzidine (NPD), N,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine (TPD), and N,N′-diphenyl-N,N′-bis[4-(phenyl-m-tolylamino)phenyl]biphenyl-4,4′-diamine (DNTPD). 
     The material for the hole transport layer is not specially limited so long as it is commonly used in the art. Examples of such materials include N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1-biphenyl]-4,4′-diamine (TPD) and N,N′-di(naphthalen-1-yl)-N,N′-diphenylbenzidine (α-NPD). 
     Subsequently, a hole auxiliary layer and the light emitting layer are sequentially laminated on the hole transport layer. A hole blocking layer may be optionally formed on the organic light emitting layer by vacuum thermal evaporation or spin coating. The hole blocking layer blocks holes from entering the cathode through the organic light emitting layer. This role of the hole blocking layer prevents the lifetime and efficiency of the device from deteriorating. A material having a very low highest occupied molecular orbital (HOMO) energy level is used for the hole blocking layer. The hole blocking material is not particularly limited so long as it has the ability to transport electrons and a higher ionization potential than the light emitting compound. Representative examples of suitable hole blocking materials include BAlq, BCP, and TPBI. 
     Examples of materials for the hole blocking layer include, but are not limited to, BAlq, BCP, Bphen, TPBI, NTAZ, BeBq 2 , OXD-7, and Liq. 
     The electron transport layer is deposited on the hole blocking layer by vacuum thermal evaporation or spin coating, and the electron injecting layer is formed thereon. A metal for the cathode is deposited on the electron injecting layer by vacuum thermal evaporation to form the cathode, completing the fabrication of the organic electroluminescent device. 
     As the metal for the formation of the cathode, there may be used, for example, lithium (Li), magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In) or magnesium-silver (Mg—Ag). The organic electroluminescent device may be of top emission type. In this case, a transmissive material, such as ITO or IZO, may be used to form the cathode. 
     The material for the electron transport layer functions to stably transport electrons injected from the cathode. The electron transport material may be any of those known in the art and examples thereof include, but are not limited to, quinoline derivatives, particularly, tris(8-quinolinolate)aluminum (Alq3), TAZ, Balq, beryllium bis(benzoquinolin-10-olate (Bebq2), ADN, and oxadiazole derivatives, such as PBD, BMD, and BND. 
     Each of the organic layers can be formed by a monomolecular deposition or solution process. According to the monomolecular deposition process, the material for each layer is evaporated under heat and vacuum or reduced pressure to form the layer in the form of a thin film. According to the solution process, the material for each layer is mixed with a suitable solvent, and then the mixture is formed into a thin film by a suitable method, such as ink-jet printing, roll-to-roll coating, screen printing, spray coating, dip coating or spin coating. 
     The organic electroluminescent device of the present invention can be used in a display or lighting system selected from flat panel displays, flexible displays, monochromatic flat panel lighting systems, white flat panel lighting systems, flexible monochromatic lighting systems, and flexible white lighting systems. 
     The present invention will be explained in more detail with reference to the following examples. However, it will be obvious to those skilled in the art that these examples are in no way intended to limit the scope of the invention. 
     Synthesis Example 1. Synthesis of Compound 1 
     Synthesis of Intermediate 1-a 
     
       
         
         
             
             
         
       
     
     5 g (26 mmol) of 1-bromo-3-chlorobenzene, 2.92 g (31 mmol) of aniline, 0.1 g (1 mmol) of palladium acetate, 5 g (52 mmol) of sodium tert-butoxide, 0.3 g (1 mmol) of bis(diphenylphosphino)-1,1′-binaphthyl, and 50 mL of toluene were placed in a 100 mL reactor. The mixture was refluxed with stirring for 24 h. After completion of the reaction, the reaction mixture was filtered. The filtrate was concentrated and purified by column chromatography to afford Intermediate 1-a (4.3 g, yield 81%). 
     Synthesis of Intermediate 1-b 
     
       
         
         
             
             
         
       
     
     20 g (98 mmol) of Intermediate 1-a, 19.3 g (98 mmol) of 2-bromobenzofuran, 0.5 g (2 mmol) of palladium acetate, 18.9 g (196 mmol) of sodium tert-butoxide, 0.8 g (4 mmol) of tri-tert-butylphosphine, and 200 mL of toluene were placed in a 250 mL reactor. The mixture was refluxed with stirring for 5 h. After completion of the reaction, the reaction mixture was filtered. The filtrate was concentrated and purified by column chromatography to afford Intermediate 1-b (20 g, yield 64%). 
     Synthesis of Intermediate 1-c 
     
       
         
         
             
             
         
       
     
     Intermediate 1-c (yield 72%) was synthesized in the same manner as in the synthesis of Intermediate 1-a, except that Intermediate 1-b was used instead of 1-bromo-3-chlorobenzene. 
     Synthesis of Intermediate 1-d 
     
       
         
         
             
             
         
       
     
     Intermediate 1-d (yield 65%) was synthesized in the same manner as in the synthesis of Intermediate 1-b, except that Intermediate 1-c and 3-bromobenzofuran were used instead of Intermediate 1-a and 2-bromobenzofuran, respectively. 
     Synthesis of Compound 1 
     
       
         
         
             
             
         
       
     
     12 g (43 mmol) of Intermediate 1-d and 120 mL of tert-butylbenzene were placed in a 300 mL reactor, and 6.9 mL (73 mmol) of n-butyllithium was added dropwise thereto at −78° C. After the dropwise addition was finished, the mixture was stirred at 60° C. for 3 h. Thereafter, the reactor was flushed with nitrogen at 60° C. to remove heptane. After dropwise addition of 12.2 g (49 mmol) of boron tribromide at −78° C., the resulting mixture was stirred at room temperature for 1 h and 6.3 g (49 mmol) of N,N-diisopropylethylamine was added dropwise thereto at 0° C. After the dropwise addition was finished, the mixture was stirred at 120° C. for 2 h. After completion of the reaction, the reaction mixture was added with an aqueous sodium acetate solution at room temperature, stirred, and extracted with ethyl acetate. The organic layer was concentrated and purified by column chromatography to give Compound 1 (1.2 g, yield 10%). 
     MS (MALDI-TOF): m/z 500.17 [M + ] 
     Synthesis Example 2. Synthesis of Compound 2 
     Compound 2 (yield 8%) was synthesized in the same manner as in Synthesis Example 1, except that 2-bromobenzothiophene was used instead of 2-bromobenzofuran used in the synthesis of Intermediate 1-b and 3-bromobenzothiophene was used instead of 3-bromobenzofuran used in the synthesis of Intermediate 1-d. 
     MS (MALDI-TOF): m/z 532.12 [M + ] 
     Synthesis Example 3. Synthesis of Compound 7 
     Compound 7 (yield 10%) was synthesized in the same manner as in Synthesis Example 1, except that 2-bromo-1-phenyl-1H-indole was used instead of 2-bromobenzofuran used in the synthesis of Intermediate 1-b and 3-bromo-1,1-dimethyl-1H-indene was used instead of 3-bromobenzofuran used in the synthesis of Intermediate 1-d. 
     MS (MALDI-TOF): m/z 601.27 [M + ] 
     Synthesis Example 4. Synthesis of Compound 13 
     Synthesis of Intermediate 4-a 
     
       
         
         
             
             
         
       
     
     60 g (177 mmol) of 1-bromo-3-(tert-butyl)-5-iodobenzene, 39.6 g (425 mmol) of aniline, 1.6 g (7 mmol) of palladium acetate, 51 g (531 mmol) of sodium tert-butoxide, 4.4 g (7 mmol) of bis(diphenylphosphino)-1,1′-binaphthyl, and 600 mL of toluene were placed in a 1 L reactor. The mixture was refluxed with stirring for 24 h. After completion of the reaction, the reaction mixture was filtered. The filtrate was concentrated and purified by column chromatography to afford Intermediate 4-a (30 g, yield 53%). 
     Synthesis of Intermediate 4-b 
     
       
         
         
             
             
         
       
     
     10 g (32 mmol) of Intermediate 4-a, 6.7 g (32 mmol) of 2-bromobenzothiophene, 0.2 g (1 mmol) of palladium acetate, 6.1 g (63 mmol) of sodium tert-butoxide, 0.3 g (1 mmol) of tri-tert-butylphosphine, and 150 mL of toluene were placed in a 250 mL reactor. The mixture was refluxed with stirring for 5 h. After completion of the reaction, the reaction mixture was filtered. The filtrate was concentrated and purified by column chromatography to afford Intermediate 4-b (9 g, yield 63%). 
     Synthesis of Compound 13 
     Compound 13 (yield 10%) was synthesized in the same manner as in Synthesis Example 1, except that Intermediate 4-b was used instead of Intermediate 1-c and 3-bromobenzothiophene was used instead of 3-bromobenzofuran used in the synthesis of Intermediate 1-d. 
     MS (MALDI-TOF): m/z 588.19 [M + ] 
     Synthesis Example 5. Synthesis of Compound 12 
     Compound 12 (yield 10%) was synthesized in the same manner as in Synthesis Example 4, except that 4-(tert-butyl)aniline was used instead of aniline used in the synthesis of Intermediate 4-a, 2-bromo-5-(tert-butyl)benzofuran was used instead of 2-bromobenzothiophene used in the synthesis of Intermediate 4-b, and 3-bromo-5-(tert-butyl)benzofuran was used instead of 3-bromobenzothiophene used in the synthesis of Compound 13. 
     MS (MALDI-TOF): m/z 780.48 [M + ] 
     Synthesis Example 6. Synthesis of Compound 29 
     Synthesis of Intermediate 6-a 
     
       
         
         
             
             
         
       
     
     30.0 g (127 mmol) of 1,5-dichloro-2,4-dinitrobenzene, 46.3 g (380 mmol) of phenylboronic acid, 2.9 g (2.5 mmol) of tetrakis(triphenylphosphine) palladium, 40.3 g (380 mmol) of sodium carbonate, 90 mL of ethanol, 150 mL of toluene, and 120 mL of water were placed in a 1 L reactor. The mixture was refluxed with stirring. After completion of the reaction, the reaction mixture was extracted with water and ethyl acetate. The organic layer was concentrated and purified by column chromatography to afford Intermediate 6-a (25 g, yield 62%). 
     Synthesis of Intermediate 6-b 
     
       
         
         
             
             
         
       
     
     25 g (78 mmol) of Intermediate 6-a, 102.4 g (390 mmol) of triphenylphosphine, and 400 mL of dichlorobenzene were placed in a 1 L reactor. The mixture was refluxed with stirring for 3 days. After completion of the reaction, the dichlorobenzene was removed, followed by column chromatography to afford Intermediate 6-b (9.8 g, yield 49%). 
     Synthesis of Intermediate 6-c 
     
       
         
         
             
             
         
       
     
     11 g (43 mmol) of Intermediate 6-b, 8.5 g (43 mmol) of 2-bromobenzofuran, 5.5 g (86 mmol) of a copper powder, 2.3 g (9 mmol) of 18-crown-6-ether, and 17.8 g (129 mmol) of potassium carbonate were placed in a 250 mL reactor, and 110 mL of dichlorobenzene was added thereto. The mixture was refluxed with stirring at 180° C. for 24 h. After completion of the reaction, the dichlorobenzene was removed, followed by column chromatography to afford Intermediate 6-c (8.5 g, yield 53%). 
     Synthesis of Intermediate 6-d 
     
       
         
         
             
             
         
       
     
     Intermediate 6-d (yield 61%) was synthesized in the same manner as in the synthesis of Intermediate 6-c, except that Intermediate 6-c and 3-bromobenzofuran were used instead of Intermediate 6-b and 2-bromobenzofuran, respectively. 
     Synthesis of Compound 29 
     
       
         
         
             
             
         
       
     
     Compound 29 (yield 12%) was synthesized in the same manner as in Synthesis Example 1, except that Intermediate 6-d was used instead of Intermediate 1-d. 
     MS (MALDI-TOF): m/z 496.14 [M + ] 
     Synthesis Example 7. Synthesis of Compound 70 
     Synthesis of Intermediate 7-a 
     
       
         
         
             
             
         
       
     
     30.0 g (89 mmol) of Intermediate 2-b, 14.7 g (98 mmol) of benzothiophen-3-ol, 24.8 g (179 mmol) of potassium carbonate, and 200 mL of NMP were placed in a 500 mL reactor. The mixture was refluxed with stirring at 160° C. for 12 h. After completion of the reaction, the reaction mixture was cooled to room temperature, distilled under reduced pressure to remove the NMP, and extracted with water and ethyl acetate. The organic layer was concentrated under reduced pressure and purified by column chromatography to afford Intermediate 7-a (27 g, yield 67%). 
     Synthesis of Compound 70 
     
       
         
         
             
             
         
       
     
     Compound 70 (yield 11%) was synthesized in the same manner as in Synthesis Example 1, except that Intermediate 7-a was used instead of Intermediate 1-d. 
     MS (MALDI-TOF): m/z 457.08 [M + ] 
     Synthesis Example 8. Synthesis of Compound 92 
     Compound 92 (yield 10%) was synthesized in the same manner as in Synthesis Example 4, except that 3,5-dibromo-N,N-diphenylaniline and benzene-d 5 -amine were used instead of 1-bromo-3-(tert-butyl)-5-iodobenzene and aniline in the synthesis of Intermediate 4-a, respectively, 2-bromobenzofuran was used instead of 2-bromobenzothiophene in the synthesis of Intermediate 4-b, and 3-bromobenzofuran was used instead of 3-bromobenzothiophene in the synthesis of Intermediate 4-c. 
     MS (MALDI-TOF): m/z 677.31 [M + ] 
     Synthesis Example 9. Synthesis of Compound 125 
     Synthesis of Intermediate 9-b 
     
       
         
         
             
             
         
       
     
     25.0 g (74 mmol) of Intermediate 9-a, 12.3 g (82 mmol) of benzothiophen-3-ol, 20.7 g (150 mmol) of potassium carbonate, and 180 mL of NMP were placed in a 500 mL reactor. The mixture was refluxed with stirring at 160° C. for 12 h. After completion of the reaction, the reaction mixture was cooled to room temperature, distilled under reduced pressure to remove the NMP, and extracted with water and ethyl acetate. The organic layer was concentrated under reduced pressure and purified by column chromatography to afford Intermediate 9-b (23 g, yield 69%). 
     Synthesis of Compound 125 
     
       
         
         
             
             
         
       
     
     Compound 125 (yield 10%) was synthesized in the same manner as in Synthesis Example 1, except that Intermediate 9-b was used instead of Intermediate 1-d. 
     MS (MALDI-TOF): m/z 457.08 [M + ] 
     Synthesis Example 10. Synthesis of Compound 126 
     Synthesis of Intermediate 10-b 
     
       
         
         
             
             
         
       
     
     20.0 g (53 mmol) of Intermediate 10-a, 12 g (59 mmol) of 5-tert-butyl-benzofuran-3-thiol, 14.8 g (107 mmol) of potassium carbonate, and 160 mL of NMP were placed in a 500 mL reactor. The mixture was refluxed with stirring at 160° C. for 12 h. After completion of the reaction, the reaction mixture was cooled to room temperature, distilled under reduced pressure to remove the NMP, and extracted with water and ethyl acetate. The organic layer was concentrated under reduced pressure and purified by column chromatography to afford Intermediate 10-b (20 g, yield 69%). 
     Synthesis of Compound 126 
     
       
         
         
             
             
         
       
     
     Compound 126 (yield 11%) was synthesized in the same manner as in Synthesis Example 1, except that Intermediate 10-b was used instead of Intermediate 1-d. 
     MS (MALDI-TOF): m/z 553.22 [M + ] 
     Synthesis Example 11. Synthesis of Compound 128 
     Synthesis of Intermediate 11-b 
     
       
         
         
             
             
         
       
     
     30.0 g (95 mmol) of Intermediate 11-a, 12 g (104 mmol) of benzothiophen-3-ol, 26.3 g (190 mmol) of potassium carbonate, and 200 mL of NMP were placed in a 500 mL reactor. The mixture was refluxed with stirring at 160° C. for 12 h. After completion of the reaction, the reaction mixture was cooled to room temperature, distilled under reduced pressure to remove the NMP, and extracted with water and ethyl acetate. The organic layer was concentrated under reduced pressure and purified by column chromatography to afford Intermediate 11-b (27 g, yield 66%). 
     Synthesis of Compound 128 
     
       
         
         
             
             
         
       
     
     Compound 128 (yield 10%) was synthesized in the same manner as in Synthesis Example 1, except that Intermediate 11-b was used instead of Intermediate 1-d. 
     MS (MALDI-TOF): m/z 438.09 [M + ] 
     Examples 1-5: Fabrication of Organic Electroluminescent Devices 
     ITO glass was patterned to have a light emitting area of 2 mm×2 mm, followed by cleaning. After the cleaned ITO glass was mounted in a vacuum chamber, the base pressure was adjusted to 1×10 −7  torr. DNTPD (700 Å) and the compound of Formula H (250 Å) were deposited in this order on the ITO. A mixture of BH1 as a host and each of Compounds 2, 7, 12, 29, and 125 (3 wt %) was used to form a 250 Å thick light emitting layer. Thereafter, the compound of Formula E-1 and the compound of Formula E-2 in a ratio of 1:1 were used to form a 300 Å thick electron transport layer on the light emitting layer. The compound of Formula E-1 was used to form a 5 Å thick electron injecting layer on the electron transport layer. A1 was deposited on the electron injecting layer to form a 1000 Å thick A1 electrode, completing the fabrication of an organic electroluminescent device. The luminescent properties of the organic electroluminescent device were measured at 0.4 mA. 
     
       
         
         
             
             
         
       
     
     Comparative Examples 1 and 2 
     Organic electroluminescent devices were fabricated in the same manner as in Example 1, except that BD1 and BD2 were used instead of the inventive compounds. The luminescent properties of the organic electroluminescent devices were measured at 0.4 mA. The structures of BH1, BD1, and BD2 are as follows. 
     
       
         
           
               
             
               
                 TABLE 1 
               
               
                   
               
             
            
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 [BH1] 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 [BD1] 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 [BD 2] 
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                 External 
                   
               
               
                   
                   
                 Current 
                   
                 quantum 
                   
               
               
                   
                   
                 density 
                 Voltage 
                 efficiency 
                 T90 
               
               
                 Example No. 
                 Dopant 
                 (mA/cm 2 ) 
                 (V) 
                 (%) 
                 (hr) 
               
               
                   
               
               
                 Example 1 
                 Compound 2 
                 10 
                 3.88 
                 8.1 
                 117 
               
               
                 Example 2 
                 Compound 7 
                 10 
                 3.92 
                 7.7 
                 108 
               
               
                 Example 3 
                 Compound 12 
                 10 
                 3.83 
                 8.3 
                 125 
               
               
                 Example 4 
                 Compound 29 
                 10 
                 3.86 
                 8.0 
                 115 
               
               
                 Example 5 
                 Compound 125 
                 10 
                 3.89 
                 7.8 
                 112 
               
               
                 Comparative 
                 BD1 
                 10 
                 4.23 
                 4.3 
                 47 
               
               
                 Example 1 
                   
                   
                   
                   
                   
               
               
                 Comparative 
                 BD2 
                 10 
                 4.11 
                 5.8 
                 52 
               
               
                 Example 2 
               
               
                   
               
            
           
         
       
     
     Examples 6-11: Fabrication of Organic Electroluminescent Devices 
     ITO glass was patterned to have a light emitting area of 2 mm×2 mm, followed by cleaning. After the cleaned ITO glass was mounted in a vacuum chamber, the base pressure was adjusted to 1×10 −7  torr. DNTPD (700 Å) and the compound of Formula F (250 Å) were deposited in this order on the ITO. A mixture of BH2 as a host and each of Compounds 1, 13, 70, 92, 126, and 128 (3 wt %) was used to form a 250 Å thick light emitting layer. Thereafter, the compound of Formula E-1 and the compound of Formula E-2 in a ratio of 1:1 were used to form a 300 Å thick electron transport layer on the light emitting layer. The compound of Formula E-1 was used to form a 5 Å thick electron injecting layer on the electron transport layer. A1 was deposited on the electron injecting layer to form a 1000 Å thick A1 electrode, completing the fabrication of an organic electroluminescent device. The luminescent properties of the organic electroluminescent device were measured at 0.4 mA. 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     Comparative Examples 3 and 4 
     Organic electroluminescent devices were fabricated in the same manner as in Example 1, except that BD3 and BD4 were used instead of instead of the inventive compounds. The luminescent properties of the organic electroluminescent devices were measured at 0.4 mA. The structures of BD3 and BD4 are as follows. 
     
       
         
           
               
             
               
                 TABLE 2 
               
               
                   
               
             
            
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 [BD3] 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 [BD4] 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                   
                   
                 External 
                   
               
               
                   
                   
                 Voltage 
                 quantum 
                   
               
               
                 Example No. 
                 Dopant 
                 (V) 
                 efficiency (%) 
                 T90 (hr) 
               
               
                   
               
               
                 Example 6 
                 Compound 1 
                 3.8 
                 8.21 
                 120 
               
               
                 Example 7 
                 Compound 13 
                 3.7 
                 8.53 
                 128 
               
               
                 Example 8 
                 Compound 70 
                 3.8 
                 8.08 
                 117 
               
               
                 Example 9 
                 Compound 92 
                 3.8 
                 8.85 
                 140 
               
               
                 Example 10 
                 Compound 126 
                 3.8 
                 8.27 
                 126 
               
               
                 Example 11 
                 Compound 128 
                 3.8 
                 8.32 
                 130 
               
               
                 Comparative 
                 BD3 
                 3.8 
                 6.04 
                 59 
               
               
                 Example 3 
                   
                   
                   
                   
               
               
                 Comparative 
                 BD4 
                 3.9 
                 5.76 
                 45 
               
               
                 Example 4