Organic electroluminescent element and process for its manufacture

Abstract

An organic EL element is formed having a crystalline CuPc film as a positive hole injection layer and a positive hole transport layer, a luminescent layer, an electron transport layer and an electron injection layer, composed of amorphous organic materials, laminated between a pair of electrodes, wherein the change in the diffraction peak value of the CuPc film appearing with X-ray diffraction, which is produced by heating in the utilization temperature range of the organic EL element, is within ±25% of the diffraction peak value before heating. The organic EL element comprising a crystalline organic material is resistant to current shorts and leaks and exhibits satisfactory luminance properties in the utilization temperature range.

What is claimed is:  
     
         1 . An organic electroluminescent element comprising 
 a substrate,    a first electrode layer on said substrate,    at least one crystalline organic material layer on said first electrode layer, and    a second electrode layer on said crystalline organic material layer(s),    wherein the change in the diffraction peak value of said crystalline organic material layer based on X-ray diffraction after heating at 120° C. is within ±25% with respect to said diffraction peak value before said heating.    
     
     
         2 . An organic electroluminescent element according to  claim 1 , wherein said first electrode is an ITO layer composed of indium-tin oxide, and said crystalline organic material layer is formed on said ITO layer in contact with said ITO layer.  
     
     
         3 . An organic electroluminescent element according to  claim 2 , wherein said crystalline organic material layer is a copper phthalocyanine layer, and said diffraction peak value is the diffraction peak value of the (200) plane of said copper phthalocyanine layer parallel to said substrate.  
     
     
         4 . An organic electroluminescent element according to  claim 1 , which further comprises at least one amorphous organic material layer on said crystalline organic material layer.  
     
     
         5 . An organic electroluminescent element comprising 
 a substrate,    an ITO layer composed of indium-tin oxide as a first electrode layer on said substrate,    a crystalline organic material layer on said ITO layer, and    a second electrode layer on said crystalline organic material layer,    wherein said ITO layer has no peak bonded water at near 330° C. in the moisture-derived spectrum of the surface as measured by thermal desorption method.    
     
     
         6 . An organic electroluminescent element according to  claim 5 , wherein said crystalline organic material layer is formed on said ITO layer in contact with said ITO layer.  
     
     
         7 . An organic electroluminescent element according to  claim 5 , wherein said crystalline organic material layer is a copper phthalocyanine layer.  
     
     
         8 . An organic electroluminescent element comprising 
 a substrate,    a first electrode layer on said substrate, said first electrode layer being an ITO layer composed of indium-tin oxide,    a crystalline organic metal complex layer on said first electrode layer,    at least one organic material layer on said crystalline organic metal complex layer, said organic material layer comprising a luminescent layer, and    a second electrode layer on said at least one organic material layer,    wherein all of the organic materials composing said organic material layer(s) exhibit volatility during film formation by vacuum vapor deposition, and the change in the diffraction peak value of said organic metal complex layer based on X-ray diffraction after heating at 120° C. is within ±25% with respect to said diffraction peak value before said heating.    
     
     
         9 . An organic electroluminescent element according to  claim 8 , wherein said organic metal complex layer is a copper phthalocyanine layer.  
     
     
         10 . An organic electroluminescent element according to  claim 8  or  9 , which is exposed to a temperature of 70° C. or higher.  
     
     
         11 . A process for manufacturing an organic electroluminescent element, which comprises the steps of 
 providing a substrate,    depositing an ITO layer composed of indium-tin oxide on said substrate,    subjecting the surface of said ITO layer to treatment for desorption of the bonded water, and    depositing a crystalline organic material layer on said ITO layer after said desorption treatment.    
     
     
         12 . A process for manufacturing an organic electroluminescent element according to  claim 11 , which is carried out so that in the moisture-derived spectrum of said ITO layer surface after said desorption treatment, measured by thermal desorption, the bonded water peak value at near 330° C. is within 50% of said bonded water peak value of said ITO layer surface before desorption treatment.  
     
     
         13 . A process for manufacturing an organic electroluminescent element according to  claim 11 , which is carried out so that in the moisture-derived spectrum of said ITO layer surface after said desorption treatment, measured by thermal desorption method, the bonded water peak value at near 330° C. disappears.  
     
     
         14 . A process for manufacturing an organic electroluminescent element according to  claim 11 , wherein said crystalline organic material layer is formed on said ITO layer in contact with said ITO layer.  
     
     
         15 . A process for manufacturing an organic electroluminescent element according to  claim 11 , wherein said crystalline organic material layer is a copper phthalocyanine layer.  
     
     
         16 . A process for manufacturing an organic electroluminescent element, which comprises the steps of 
 providing a substrate,    depositing an ITO layer composed of indium-tin oxide on said substrate,    subjecting said ITO layer to heat treatment at a temperature of 250° C. or higher, and    depositing a crystalline organic material layer on said ITO layer after said heat treatment.    
     
     
         17 . A process for manufacturing an organic electroluminescent element according to  claim 16 , wherein said crystalline organic material layer is formed on said ITO layer in contact with said ITO layer.  
     
     
         18 . A process for manufacturing an organic electroluminescent element according to  claim 16 , wherein said crystalline organic material layer is a copper phthalocyanine layer.  
     
     
         19 . A process for manufacturing an organic electroluminescent element, which comprises the steps of 
 providing a substrate,    depositing an ITO layer composed of indium-tin oxide on said substrate, and    depositing a crystalline organic material layer on said ITO layer, and then subjecting said crystalline organic material layer to heat treatment in a vacuum or in an inert gas atmosphere, to complete deposition of said crystalline organic material layer.    
     
     
         20 . A process for manufacturing an organic electroluminescent element according to  claim 19 , wherein said heat treatment temperature is 70° C. or higher.  
     
     
         21 . A process for manufacturing an organic electroluminescent element according to  claim 19 , wherein said crystalline organic material layer is formed on said ITO layer in contact with said ITO layer.  
     
     
         22 . A process for manufacturing an organic electroluminescent element according to  claim 19 , wherein said crystalline organic material layer is a copper phthalocyanine layer.