Organic electroluminescent element

Abstract

A main object of the present invention is to provide an organic EL element which can ease damages of an organic EL layer upon formation of an electrode layer, and enables display of a high quality image. The present invention attains the above object by providing an organic electroluminescent element comprising: a substrate; a first electrode layer formed on the substrate; an organic electroluminescent layer which is formed on the first electrode layer, and has at least a light emitting layer; a semiconductor buffer layer which is formed on the organic electroluminescent layer, and contains an inorganic compound having a band gap of 2.0 eV or more and a metal; and a second electrode layer formed on the semiconductor buffer layer.

1 . An organic electroluminescent element comprising: a substrate; a first electrode layer formed on the substrate; an organic electroluminescent layer which is formed on the first electrode layer, and has at least a light emitting layer; a semiconductor buffer layer which is formed on the organic electroluminescent layer, and contains an inorganic compound having a band gap of 2.0 eV or more and a metal; and a second electrode layer formed on the semiconductor buffer layer.  
   
   
       2 . An organic electroluminescent element comprising: a substrate; an electrode layer formed on the substrate; an organic electroluminescent layer which is formed on the electrode layer and has at least a light emitting layer; and a semiconductor electrode layer which is formed on the organic electroluminescent layer and contains an organic compound having a band gap of 2.0 eV or more and a metal.  
   
   
       3 . The organic electroluminescent element according to  claim 1 , wherein the semiconductor buffer layer or the semiconductor electrode layer is a mixed semiconductor layer in which the metal is dispersed in the inorganic compound.  
   
   
       4 . The organic electroluminescent element according to  claim 2 , wherein the semiconductor buffer layer or the semiconductor electrode layer is a mixed semiconductor layer in which the metal is dispersed in the inorganic compound.  
   
   
       5 . The organic electroluminescent element according to  claim 1 , wherein the semiconductor buffer layer comprises: an inorganic layer comprising the inorganic compound; and a metal layer comprising the metal, and 
 the metal layer is formed in the inorganic layer, or between the inorganic layer and the second electrode layer.    
   
   
       6 . The organic electroluminescent element according to  claim 2 , wherein the semiconductor electrode layer comprises: an inorganic layer comprising the inorganic compound; and a metal layer comprising he metal, and 
 the metal layer is formed in the inorganic layer, or on an opposite side to a side on which the organic electroluminescent layer is formed.    
   
   
       7 . The organic electroluminescent element according to  claim 1 , wherein the semiconductor buffer layer or the semiconductor electrode layer comprises: a mixed semiconductor layer in which the metal is dispersed in the inorganic compound; and an inorganic layer comprising the inorganic compound.  
   
   
       8 . The organic electroluminescent element according to  claim 2 , wherein the semiconductor buffer layer or the semiconductor electrode layer comprises: a mixed semiconductor layer in which the metal is dispersed in the inorganic compound; and an inorganic layer comprising the inorganic compound.  
   
   
       9 . The organic electroluminescent element according to  claim 1 , wherein the semiconductor buffer layer or the semiconductor electrode layer comprises: a mixed semiconductor layer in which the metal is dispersed in the inorganic compound; and a metal layer comprising the metal.  
   
   
       10 . The organic electroluminescent element according to  claim 2 , wherein the semiconductor buffer layer or the semiconductor electrode layer comprises: a mixed semiconductor layer in which the metal is dispersed in the inorganic compound; and a metal layer comprising the metal.  
   
   
       11 . The organic electroluminescent element according to  claim 1 , wherein an electric resistivity ρ of the metal is less than 1×10 −5  Ω·cm.  
   
   
       12 . The organic electroluminescent element according to  claim 2 , wherein work function of a metal contained in the semiconductor electrode layer is 4.2 eV or more.  
   
   
       13 . The organic electroluminescent element according to  claim 1 , wherein the inorganic compound is an inorganic semiconductor compound.  
   
   
       14 . The organic electroluminescent element according to  claim 13 , wherein the inorganic semiconductor compound is a compound containing at least one kind of element selected from elements of Group 12 to Group 16 in 18 Group-type Element Periodic Table.  
   
   
       15 . The organic electroluminescent element according to  claim 1 , wherein the inorganic compound is a metal compound containing at least one kind of element selected from elements of Group 17 in 18 Group-type Element Periodic Table.  
   
   
       16 . The organic electroluminescent element according to  claim 1 , wherein the semiconductor buffer layer or the semiconductor electrode layer has a thickness in a range of 1 nm to 500 nm, and an average light transmittance in a visible region is 30% or more.  
   
   
       17 . The organic electroluminescent element according to  claim 1 , wherein a content of the metal in the semiconductor buffer layer or the semiconductor electrode layer is in a range of 0.0001% by volume to 90% by volume.  
   
   
       18 . The organic electroluminescent element according to  claim 1 , wherein the metal is contained in the semiconductor buffer layer or the semiconductor electrode layer so that, when a metal contained in the semiconductor buffer layer or the semiconductor electrode layer is formed into a layer consisting only of the metal, a thickness of the layer consisting only of the metal is 100 nm or less.  
   
   
       19 . The organic electroluminescent element according to  claim 1 , wherein the semiconductor buffer layer or the semiconductor electrode layer is formed into a film by a vacuum deposition method.  
   
   
       20 . The organic electroluminescent element according to  claim 1 , wherein a charge injecting/transporting layer is formed between the light emitting layer, and the semiconductor buffer layer or the semiconductor electrode layer.