Method for forming multi-layer cathode in organic light-emitting devices

Abstract

A method for manufacturing an organic light-emitting device includes forming an anode over a substrate, at least one organic light-emitting layer over the anode, a buffer layer over the organic light emitting layer, and a cathode over the buffer layer. The cathode is formed of first, second and third cathode layers. The first cathode layer is formed of a conductive material. A second cathode layer of electron transport material is formed over the first cathode layer and a third cathode layer of conductive material is formed over the second cathode layer.

1 . A method of manufacturing a cathode in an organic light-emitting device, the method comprising: 
 forming a first cathode layer comprising conductive material over a buffer layer of the organic light-emitting device;    forming a second cathode layer comprising electron transport material over the first cathode layer; and    forming a third cathode layer comprising conductive material over the second cathode layer.    
   
   
       2 . The method of  claim 1 , wherein the forming a first cathode layer comprises physical vapor deposition.  
   
   
       3 . The method of  claim 1 , wherein the forming a first cathode layer comprises thermal evaporation or e-beam deposition  
   
   
       4 . The method of  claim 1 , wherein the first cathode layer comprises aluminum, magnesium or calcium.  
   
   
       5 . The method of  claim 1 , wherein the forming a third cathode layer comprises sputtering at a rate faster than 10 angstroms per second.  
   
   
       6 . The method of  claim 1 , wherein the second cathode layer comprises at least one high conjugation organic material having more than 15 π bonds.  
   
   
       7 . The method of  claim 6 , wherein the high conjugation organic material comprises at least one of phthalocyanine, triarylamine, polyaryl, C60, and PPV.  
   
   
       8 . The method of  claim 1 , wherein the first cathode layer comprises metal, the second cathode layer comprises phthalocyanine, the third cathode layer comprises an alkaline metal alloy, and the buffer layer comprises an alkaline halide.  
   
   
       9 . The method of  claim 1 , wherein the third cathode layer comprises an alkaline metal alloy.  
   
   
       10 . The method of  claim 1 , wherein the forming a first cathode layer comprises providing an aluminum tablet on a tungsten retaining member in a vacuum chamber and heating the tungsten retaining member.  
   
   
       11 . The method of  claim 10 , wherein the heating comprises heating to a temperature greater than the sublimation temperature of aluminum.