Organic semiconductor devices and organic electroluminescent devices produced by using wet process

Abstract

The present invention provides a method for manufacturing an organic semiconductor thin film by a wet process with a composite solution prepared by dissolving at least two organic semiconductor compounds in a mixed organic solvent including at least two organic solvents having different volatility and having different solubilities of the organic compounds at room temperature. Due to the differences in the evaporation speeds of the solvents and the solubilities of the organic compounds, the organic compounds are continuously deposited according to the composition of solvent that sequentially evaporates. Thus, the organic semiconductor thin film having a continuous multi-layer (non-boundary multi-layer) structure can be manufactured where different organic compounds coexist between the organic layers. Especially, the composite solution including at least two organic EL materials are used, and the organic materials are controlled to deposit on the anode in the order of hole injecting—hole transporting—light emitting—electron transporting—electron injecting layers to form an organic EL device.

1 . An organic semiconductor device, comprising: 
 an organic semiconductor thin film having a continuous non-boundary multi-layer structure, formed by a wet film formation process with a composite solution prepared by dissolving at least two organic compounds in a mixed organic solvent including at least two organic solvents having different volatility and having different solubilities of the organic compounds;    and electrodes for applying a voltage to the thin film.    
     
     
         2 . The device of  claim 1 , wherein the organic semiconductor thin film is an organic light emitting thin film including at least two organic layers deposited in the order of hole injecting layer, hole transporting layer, light-emitting layer, electron transporting layer and electron injecting layer on an anode.  
     
     
         3 . The device of  claim 1 , wherein the organic semiconductor thin film has a thickness of 0.001 to 1 μm.  
     
     
         4 . The device of  claim 1 , wherein the organic semiconductor thin film is an organic light emitting thin film, and the electrodes have a passive matrix or an active matrix electrode structure.  
     
     
         5 . The device of  claim 1 , wherein the organic semiconductor thin film is an organic light emitting thin film, and the organic semiconductor device is used for a device selected from the group consisting of televisions, digital cameras, computers, notebook computers, mobile computers, portable image recording or displaying device, screens, bulletin boards, store signs, goggle type displays, car displays, video cameras, printer displays, remote control devices, phone displays and mobile phones.  
     
     
         6 . An organic semiconductor device comprising: 
 an organic semiconductor thin film including at least two organic compounds, wherein the organic compounds are continuously deposited so that the concentrations of the organic compounds change with a gradient along with the deposition direction thereof; and    electrodes for applying a voltage to the organic semiconductor thin film.    
     
     
         7 . A method for manufacturing an organic semiconductor device, comprising the steps of: 
 coating a composite solution on a substrate, wherein the composite solution is prepared by dissolving at least two organic compounds in a mixed organic solvent including at least two organic solvents having different volatility and having different solubilities of the organic compounds; and    continuously depositing the at least two organic compounds by evaporating the organic solvents from the coated composite solution.    
     
     
         8 . The method of  claim 7 , wherein the organic compounds are at least two organic compounds selected from the group consisting of compounds for forming hole injecting layer, hole transporting layer, light-emitting layer, electron transporting layer and electron injecting layer, and the organic semiconductor device is an organic light emitting device.  
     
     
         9 . The method of  claim 8 , wherein the organic compounds further include a dopant and/or a binder resin.  
     
     
         10 . The method of  claim 7 , wherein the step for coating the composite solution on the substrate is performed by a method selected from the group consisting of a printing method, an inkjet method, spin coating, and a dipping method.  
     
     
         11 . The method of  claim 7 , further comprising the steps of: 
 forming an electrode after depositing the organic compounds; and    encapsulating the electrode and the deposited organic compounds under an inert gas atmosphere.    
     
     
         12 . The method of  claim 7 , wherein the organic solvents are selected from the group consisting of methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, dimethylformamide, dimethylacetamide, ketone, acetone, diacetone alcohol, keto-alcohol, dioxane, ether, polyethylene glycol, polypropylene glycol, polyalkylene glycol, ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, hexylene glycol, diethylene glycol, glycerol, ethyleneglycol monomethyl ether, diethyleneglycol methylether, triethyleneglycol monomethylether, 2-pyrrolidon, toluene, xylene, chlorobenzene, dichlorobenzene, chloroform, dichloromethane, dichloroethane, gamma-butyl lactone, butyl cellosolve, cyclohexane, NMP(N-methyl-2-pyrrolidon), cyclohexanone, tetrahydrofurane(THF), carbon tetrachloride, tetrachloroethane, octylbenzene, dodecylbenzene, quinoline, trichlorobenzene, nitrobenzaldehyde, nitrobenzene, carbon disulfide, 2-heptanone, benzene, terpineol, butylcarbitolacetate and ion exchange water.  
     
     
         13 . The method of  claim 7 , wherein a concentration of the organic compounds in the composite solution ranges from 0.005 to 10 wt %.  
     
     
         14 . The method of  claim 7 , wherein a viscosity of the composite solution is less than 5000 cp.  
     
     
         15 . The method of  claim 7 , wherein the organic semiconductor device is an organic light emitting device, and the step for continuously depositing the organic compounds is separately carried out for red, green and blue pixels.  
     
     
         16 . A composite solution for producing an organic thin film comprising: 
 at least two organic compounds to form the organic thin film; and    a mixed organic solvent including at least two organic solvents having different volatility and having different solubilities of the organic compounds.    
     
     
         17 . The composite solution of  claim 16 , wherein the at least two organic solvents are selected from the group consisting of methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tertbutyl alcohol, dimethylformamide, dimethylacetamide, ketone, acetone, diacetone alcohol, keto-alcohol, dioxane, ether, polyethylene glycol, polypropylene glycol, polyalkylene glycol, ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, hexylene glycol, diethylene glycol, glycerol, ethyleneglycol monomethyl ether, diethyleneglycol methylether, triethyleneglycol monomethylether, 2-pyrrolidon, toluene, xylene, chlorobenzene, dichlorobenzene, chloroform, dichloromethane, dichloroethane, gamma-butyl lactone, butyl cellosolve, cyclohexane, NMP(N-methyl-2-pyrrolidon), cyclohexanone, tetrahydrofurane(THF), carbon tetrachloride, tetrachloroethane, octylbenzene, dodecylbenzene, quinoline, trichlorobenzene, nitrohenzaldehyde, nitrobenzene, carbon disulfide, 2-heptanone, benzene, terpineol, butylcarbitolacetate and ion exchange water.  
     
     
         18 . The composite solution of  claim 16 , wherein a concentration of the organic compounds in the composite solution ranges from 0.005 to 10 wt %.  
     
     
         19 . The composite solution of  claim 16 , wherein a viscosity of the composite solution is less than 5000 cp.