Organic electroluminescent element

Abstract

Disclosed is an organic electroluminescent element, comprising an anode and a cathode, an organic light-emitting layer interposed between the anode and the cathode, and an organic hole transfer layer containing a polymer type organic hole transfer material having a metal oxide of a semiconductor material or a conductive material added thereto.

1 . An organic electroluminescent element, comprising: 
 an anode and a cathode;    an organic light-emitting layer interposed between the anode and the cathode; and    an organic hole transfer layer containing a polymer type organic hole transfer material having a metal oxide of a semiconductor material or a conductive material added thereto.    
   
   
       2 . The organic electroluminescent element according to  claim 1 , wherein both the metal oxide and the polymer type organic hole transfer material are soluble in water.  
   
   
       3 . The organic electroluminescent element according to  claim 1 , wherein the polymer type organic hole transfer material is poly(ethylenedioxy)thiophene doped with polystyrenesulphonic acid or a salt thereof (PSS).  
   
   
       4 . The organic electroluminescent element according to  claim 3 , wherein the poly(ethylenedioxy)thiophene is poly(2,3-ethylenedioxy) thiophene (PEDOT).  
   
   
       5 . The organic electroluminescent element according to  claim 1 , wherein the metal oxide is at least one oxide selected from the group consisting of MoO x , where x denotes an integer of 2 to 3 and VO x , where x is an integer of 1 to 2.5.  
   
   
       6 . The organic electroluminescent element according to  claim 1 , wherein the polymer type organic hole transfer material is a water-soluble PEDOT:PSS prepared by having poly(3,4-ethylenedioxy)thiophene doped with polystyrenesulphonic acid or a salt thereof, the metal oxide is a water-soluble MoO x  (where x is an integer of 2 to 3), the water-soluble PEDOT:PSS is mixed with the water-soluble MoO x  in the presence of water, and the mixed aqueous solution is used for forming the polymer type organic hole transfer layer on the anode by the ink jet method or a printing method.  
   
   
       7 . The organic electroluminescent element according to  claim 1 , wherein the organic light-emitting layer is formed of a material having a polymer type polyparaphenylene vinylene skeleton or a polyfluorene skeleton.  
   
   
       8 . The organic electroluminescent element according to  claim 1 , wherein the cathode has a stacked structure comprising a layer of an alkali metal or an alkaline earth metal such as Li, Ca, Ba and an Al layer stacked on the layer of the alkali metal or the alkaline earth metal.  
   
   
       9 . The organic electroluminescent element according to  claim 1 , further comprising a cathode buffer layer formed of CsF, which is interposed between the cathode and the organic light-emitting layer.