Organic electroluminescent element, display device and lighting device

Abstract

An organic EL element, which has high light emission efficiency, a long light emission life and a small color change when continuously driven, an illuminating device and a display device are provided. Especially, an organic EL element which emits white light and can be manufactured at low cost is provided.

1 . An organic electroluminescent element comprising a light emitting layer sandwiched between an anode and a cathode, wherein the light emitting layer contains at least two phosphorescence emitting metal complexes, provided that one of the phosphorescence emitting metal complexes has a ligand made of a six-membered aromatic compound condensed with three or more rings each having a five or a six-membered aromatic ring. 
     
     
         2 . The organic electroluminescent element of  claim 1 , wherein the one of the two phosphorescence emitting metal complexes has a partial structure represented by one of the following Formulas (1) to (4): 
       
         
           
           
               
               
           
         
         wherein, E1a to E1q each represent a carbon atom or a nitrogen atom; R1a to R1i each represent a hydrogen atom or a substituent; and M represents a transition metal of Group 8 to Group 10 in the periodic table. 
       
     
     
         3 . The organic electroluminescent element of  claim 1 , wherein the two phosphorescence emitting metal complexes each emits a light of a different hue, and the phosphorescence emitting metal complex having a ligand made of a six-membered aromatic compound condensed with three or more rings each having a five or a six-membered aromatic ring emits a blue light. 
     
     
         4 . The organic electroluminescent element of  claim 1 , wherein a difference of highest occupied molecular orbitals (HOMO) of the at least two phosphorescence emitting metal complexes is 0.5 eV or less. 
     
     
         5 . The organic electroluminescent element of  claim 1 , comprising at least two light emitting layers as constituting layers, provided that each of the two phosphorescence emitting metal complexes are contained in a different light emitting layer. 
     
     
         6 . The organic electroluminescent element of  claim 1 , wherein M represents platinum or iridium. 
     
     
         7 . The organic electroluminescent element of  claim 1 , wherein at least one of the light emitting layer is produced with a wet process. 
     
     
         8 . The organic electroluminescent element of  claim 1 , emitting a white light. 
     
     
         9 . A display device comprising the organic electroluminescent element of  claim 1 . 
     
     
         10 . A lighting device comprising the organic electroluminescent element of  claim 1 .