Electroluminescent device having an organic layer including polyimide

Abstract

An electroluminescent device comprising a transparent electrode layer, a metallic electrode layer, and an organic interlayer disposed between, and in close contact with, the electrode layers wherein the organic interlayer is comprised of an organic luminescent layer, an optional hole transport layer and an optional electron transport layer, and contains a polyimide of formula (I): wherein A is a moeity derived from a dianhydride compound; B is a moiety derived from a diamine compound; and n is an integer of 2 or higher.

What is claimed is:  
     
         1 . An electroluminescent device comprising a transparent electrode layer, a metallic electrode layer, and an organic interlayer disposed between, and in close contact with, the electrode layers wherein the organic interlayer is comprised of an organic luminescent layer, an optional hole transport layer and an optional electron transport layer, and contains a polyimide of formula (I):  
       
         
           
           
               
               
           
         
       
       wherein A is a moiety derived from a dianhydride compound; B is a moiety derived from a diamine compound; and n is an integer of 2 or higher.  
     
     
         2 . The electroluminescent device of  claim 1  further comprising a polyimide buffer layer arranged between the organic interlayer and the electrode layers.  
     
     
         3 . The electroluminescent device of  claim 1 , wherein the polyimide is a polyetherimide of formula (II):  
       
         
           
           
               
               
           
         
       
     
     
         4 . The electroluminescent device of  claim 1 , wherein the polyimide is derived from a polyimide precursor selected from the group consisting of a poly(amic acid) of formula (III), a polyamic dialkylester of formula (VI), a covalent type photosensitive polyimide precursor of formula (VII), an ionic type photosensitive polyimide precursor of formula (VIII) and a mixture thereof:  
       
         
           
           
               
               
           
         
       
       wherein R is an alkyl group; R* is a covalent type photosensitive group; and R +  is an ionic type photosensitive group.  
     
     
         5 . The electroluminescent device of  claim 1 , wherein the polyimide is derived from: 
 a dianhydride selected from the group consisting of pyromelliticdianhydride, 3,4,3′,4′-biphenyl-tetracarboxylic dianhydride, 3,3′,4,4′-benzophenone tetracarboxylic dianhydride, 4,4′-(hexafluoropropylidene)-diphthalic anhydride, 4,4′-(dimethylsilicon)diphthalic anhydride, 4,4′-oxydiphthalic anhydride, 3,3′,4,4′-diphenylsulfone tetracarboxylic dianhydride, 1,2,3,4-cyclopentane tetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride, 3,4,9,10-perylene tetracarboxylic dianhydride, 4-(2,5-dioxotetrahydrofuran-3-yl)tetralin-1,2-dicarboxylic anhydride, 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 2,2′-di-tert-butylbiphenyl-bis(etherphthalic anhydride), 2,5-di-tert-butylphenyl-bis(etherphthalic anhydride) and bisphenol A-bis(ether-phthalic anhydride); and    a diamine selected from the group consisting of 4,4′-diaminodiphenylether, 4,4′-diamino-diphenylmethane, 2,2-bis(4-aminophenyl)propane, 3,5-diaminotoluene, 3,4-diaminodiphenylether, 3,4-diamino-diphenylmethane, 4,4′-phenylene diamine, 3,4-phenylene diamine, 3,3′-diaminodiphenylether, 3,3′-diaminodiphenyl-methane, 2,5-dimethyl-p-phenylene diamine, 2,3,5,6-tetramethyl-p-phenylene diamine, diaminofluorene, diaminofluorenone, 4,4′-diaminobenzophenone, 4,4′-diaminobiphenyl, 3,3′-diaminobenzophenone, 4, 4′-diaminosulfide, α,α′-bis(4-aminophenyl)-1,4-diisopropyl-benzene, 2,2-bis[4-(4-aminophenoxy)phenyl]-propane, 1,4-bis(4-aminophenoxy)benzene, 2,2-bis[4-(3-aminophenoxy)-phenyl]hexafluoropropane, 2,6-diaminotoluene, mesitylene diamine, 4,4′-diaminodiphenyl-sulfone, 3,3′-diaminodiphenyl-sulfone, 3,3′-bis(aminophenyl)-hexafluoropropane, 2,2-bis(3-amino-4-hydroxylphenyl)hexa-fluoropropane, 4,4′-bis(2-chloroanilino)methane, 4,4′-bis(aminocyclohexyl)methane, 2,2′-bis(3-amino-4-methyl-phenyl)hexafluoropropane, 3,4′-diaminobenzophenone, 4,4′-diaminobibenzyl, 4,4′-bis(aminophenyl)hexafluoropropane, 1,3′-bis(m-amino-phenoxy)benzene, 4,4′-methylene-bis-o-toluidine, 3,3′-diamino-4,4′-dihydroxybiphenyl, 4,4′-diaminooctafluoro-diphenyl, 4,4′-bis(aminophenyl)selenide, 9,10-bis(3-amino-phenylthio)anthracene, 9,10-bis(4-aminophenylthio)-anthracene, 9,10-bis(3-aminoanilino)-anthracene, 9,10-bis(4-aminoanilino)anthracene, acridine yellow G, acriflavine, 3,6-diaminoacridine, 6,9-diamino-2-ethoxyacridine, basic fuchsin, methylated basic fuchsin, 2,4-diamino-6-phenyl-1,3,5-triazine, 9,10-diaminophen-anthrene, 3,8-diamino-6-phenylphenanthridine, dimidium bromide, ethidium bromide, propidium iodide, thionin, 3,7-diamino-5-phenylphenazium chloride and 3,3′-dimethylnaphthidine.    
     
     
         6 . The electroluminescent device of  claim 1 , wherein the organic luminescent layer contains an electroluminescent material selected from the group consisting of tris(8-hydroxyquinolinolato)aluminum, 1,1,4,4-tetraphenyl-1,3-butadiene, oligophenylenevinylene derivatives, 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran, 1,4-distyrylbenzene, anthracene, tetracene, pentracene, coronene, perylene, pyrene, bis(8-quinolinolato) zinc(II), 9,10-diphenylanthracene, tris(4,4,4-trifluoro-1-(2-thienyl)-l,3-butandiono)-1,10-phenanthroline europium(III), tris(2,4-pentadiono)-1,10-phenanthroline terbium(III), tris(4,4,4-trifluoro-1-(2-thienyl)-1,3-butandiono)-1,10-phenanthroline dysprosium(III) and a mixture thereof.  
     
     
         7 . The electroluminescent device of  claim 6 , wherein the amount of the electroluminescent material ranges from 5 to 70 wt % based on the total weight of the organic luminescent layer.  
     
     
         8 . The electroluminescent device of  claim 1 , wherein the hole transport layer contains a hole transport agent selected from the group consisting of N,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-diphenyl-4,4′-diamine(TPD), poly(N-vinylcarbazole) and a mixture thereof.  
     
     
         9 . The electroluminescent device of  claim 1 , wherein the hole transport layer contains a polyaniline doped with an acid selected from the group consisting of dodecylbenzenesulfonic acid, camphor sulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid and 5-sulfosalicylic acid.  
     
     
         10 . The electroluminescent device of  claim 9 , wherein the amount of the hole transport agent ranges from 5 to 80 wt % based on the total weight of the hole transport layer.  
     
     
         11 . The electroluminescent device or  claim 1  wherein, the electron transport layer contains an electron transport agent selected from the group consisting of an oxadiazole derivative, an imide derivative and a mixture thereof.  
     
     
         12 . The electroluminescent device of  claim 3 , wherein the organic interlayer is comprised of an organic luminescent layer, and a hole transport layer containing a hole transport agent selected from the group consisting of N,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-diphenyl-4,4′-diamine(TPD), poly(N-vinylcarbazole) and a mixture thereof and a polyetherimide of formula (II) in a weight ratio ranging from 10:90 to 90:10.  
     
     
         13 . The electroluminescent device of  claim 3 , wherein the organic luminescent layer contains an organic luminescent material and a polyetherimide of formula (II) in a weight ratio ranging from 5:95 to 70:30.  
     
     
         14 . The electroluminescent device of  claim 3 , wherein the organic interlayer is comprised of an organic luminescent layer, and a hole transport layer containing the three elements of a polyetherimide of formula (II), a hole transport agent and an organic luminescent material in a weight ratio ranging from 4:3:3 to 5:4:1.  
     
     
         15 . The electroluminescent device of  claim 1 , wherein the organic interlayer is comprised of an organic luminescent layer, and a hole transport layer prepared by coating a mixture of an acid-doped polyaniline and a polyimide precursor in a weight ratio ranging from 2:98 to 95:5 to form a coating layer and then subjecting the coating layer to thermal imidization.  
     
     
         16 . The electroluminescent device of  claim 3 , wherein the organic interlayer is comprised of an organic luminescent layer, and a hole transport layer containing an acid-doped polyaniline and a polyetherimide of formula (II) in a weight ratio ranging from 5:95 to 80:20.  
     
     
         17 . The electroluminescent device of  claim 1 , wherein the organic luminescent layer is prepared by coating a mixture of an organic luminescent material and a polyimide precursor in a weight ratio ranging from 2:98 to 95:5 to form a coating layer and then subjecting the coating layer to thermal imidization.  
     
     
         18 . The electroluminescent device of  claim 3 , wherein the organic interlayer is comprised of a hole transport layer containing a hole transport agent and a polyetherimide of formula (II) in a weight ratio ranging from 5:95 to 70:30, and an organic luminescent layer containing an organometallic compound having both luminescent and electron transport activities and a polyetherimide of formula (II) in a weight ratio ranging from 5:95 to 70:30.  
     
     
         19 . The electroluminescent device of  claim 1  or  3 , wherein the organic interlayer is comprised of a hole transport layer prepared by coating a mixture of a doped polyaniline and a polyimide precursor in a weight ratio ranging from 2:98 to 95:5 to form a coating layer and then subjecting the coating layer to thermal imidization, and an organic luminescent layer containing an organic luminescent agent and a polyetherimide of formula (II) in a weight ratio ranging from 5:95 to 70:30.