Organic white-light-emitting blend materials and electroluminescent devices fabricated using the same

Abstract

Organic white-light-emitting blend materials were prepared by light-doping method and electroluminescent devices fabricated using the same, including a transparent substance, translucent electrode, white-light-emitting layer and metal electrode in order, can efficiently control Forster energy transfer in organic light-emitting materials by performing light doping, thus to fabricate a white electroluminescent device using the blend materials which can emit white-light with high efficiency. The white-light-emitting blend materials can be obtained by the light-doping method, in which the energy transfer occurs only between a host which is a donor and each dopant which is an acceptor, while the energy transfers between dopants are efficiently blocked.

What is claimed is:  
     
         1 . Organic white light-emitting blend materials which comprise three or more organic light-emitting material components, in which a component having the highest bandgap energy is a host, the rest components are dopants, and the dopants are lightly doped to the host with an amount of 0.1 wt % or below based on the total weight.  
     
     
         2 . The materials of  claim 1 , wherein when optical excitation is conducted at the absorption peak wavelength of the host material, Förster energy transfer occurs from the host to the respective dopants to make the photoluminescence intensity of the dopants similar to that of the host, whereas there is no affection by the Förster energy transfer between the respective dopants.  
     
     
         3 . The materials of  claim 1 , wherein the respective organic light-emitting material components are selected from the group consisting of light-emitting conjugated polymers, light-emitting non-conjugated polymers, organic low-molecular light-emitting materials, and copolymers of the above materials.  
     
     
         4 . The materials of  claim 3 , wherein the light-emitting conjugated polymers comprise poly(p-phenylenevinylene) and its derivatives, polythiophene and its derivatives, poly(p-phenylene) and its derivatives, polyfluorene and its derivatives, polyquinoline and its derivatives, polyacetylene and its derivatives, and polypyrrole and its derivatives; and 
 the light-emitting non-conjugated polymers comprise poly(9-vinylcarbarzole) and its derivatives.    
     
     
         5 . The materials of  claim 4 , wherein the organic low-molecular light-emitting materials comprise metal complex compound of a ligand structure, rubrene, anthracene, perylene, coumarin 6, Nile Red, aromatic diamine, TPD(N, N′-diphenyl-N,N′-bis-(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine), TAZ(3-(4-biphenyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole), DCM(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran), and derivatives of the above materials.  
     
     
         6 . An electroluminescent device, comprising: 
 a substrate having a transparent substrate and a translucent electrode thereon;    a luminescent layer which is formed on the translucent electrode; and    a metal electrode which is formed on the luminescent layer,    wherein the luminescent layer is composed of three or more organic light-emitting material components, in which a component having the highest bandgap energy is a host, the rest components are dopants, and the dopants are lightly doped to the host with an amount of 0.1 wt % or below based on the total weight.    
     
     
         7 . The device of  claim 6 , wherein the transparent substrate is selected from the group consisting of glass, quartz, and PET(polyethylene terephtalate) plate which is a transparent plastic material.  
     
     
         8 . The device of  claim 6 , wherein the translucent electrode is selected from the group consisting of ITO(indium tine oxide), PEDOT(polyethylene dioxythiophene), and polyaniline.  
     
     
         9 . The device of  claim 6 , the metal electrode is selected from the group consisting of aluminum, magnesium, lithium, calcium, copper, silver, gold and an alloy of the above materials.  
     
     
         10 . An electroluminescent device, comprising: 
 a substrate having a transparent substrate and a translucent electrode thereon;    a hole transporting layer which is formed on the translucent electrode;    a luminescent layer which is formed on the hole transporting layer; and    a metal electrode which is formed on the luminescent layer,    wherein the luminescent layer is composed of three or more organic light-emitting material components, in which a component having the highest bandgap energy is a host, the rest components are dopants, and the dopants are lightly doped to the host with an amount of 0.1 wt % or below based on the total weight.    
     
     
         11 . The device of  claim 10 , wherein the hole transporting layer is composed of one or more materials which are selected from the group consisting of polymers including polyvinylcarbazole and its derivatives; organic low-molecular materials including 4,4′-dicarbazolyl-1,1′-biphenyl(CBP), TPD(N,N′-diphenyl-N,N′-bis-(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine), NPB(4,4′-bis[N-(1-naphthyl-1-)-N-phenyl-amino]-biphenyl), triarylamine, pyrazoline and their derivatives; and organic low-molecular and polymer materials containing a hole transporting moiety.  
     
     
         12 . An electroluminescent device, comprising: 
 a substrate having a transparent substrate and a translucent electrode thereon;    a luminescent layer which is formed on the translucent electrode    an electron transporting layer which is formed on the luminescent layer; and    a metal electrode which is formed on the electron transporting layer,    wherein the luminescent layer is composed of three or more organic light-emitting material components, in which a component having the highest bandgap energy is a host, the rest components are dopants, and the dopants are lightly doped to the host with an amount of 0.1 wt % or below based on the total weight.    
     
     
         13 . The device of  claim 10 , wherein the electron transporting layer is composed of one or more materials which are selected from the group consisting of TPBI(2,2′, 2′-(1,3,5-phenylene)-tris[1-phenyl-1H-benzimidazole]), poly(phenyl quinoxzline), 1,3,5-tris[(6,7-dimethyl-3-phenyl)quinoxaline-2-yl]benzene(Me-TPQ), polyquinoline, tris(8-hydroxy quinoline)aluminum(Alq3), {6-N,N-diethylamino-1-methyl-3-phenyl-1H-pyrazolo[3,4-b]quinoline}(PAQ-NEt2), and low-molecular and polymer materials containing an electron transporting moiety.  
     
     
         14 . An electroluminescent device, comprising: 
 a substrate having a transparent substrate and a translucent electrode thereon;    a hole transporting layer which is formed on the translucent electrode;    a luminescent layer which is formed on the hole transporting layer;    an electron transporting layer which is formed on the luminescent layer; and    a metal electrode which is formed on the electron transporting layer,    wherein the luminescent layer is composed of three or more organic light-emitting material components, in which a component having the highest bandgap energy is a host, the rest components are dopants, and the dopants are lightly doped to the host with an amount of 0.1 wt % or below based on the total weight.