Organic electroluminescent display device having superior characteristics at high temperature

Abstract

An organic electroluminescent display device improves driving characteristics at a high temperature and storage characteristics of the organic electroluminescent display device, and prevents pixel contraction phenomena of the device by providing an organic electroluminescent display device comprising a substrate, a first electrode and a second electrode formed on the substrate, and an organic film layer comprising at least one emitting layer between the first electrode and the second electrode. The emitting layer includes at least one phosphorescent dopant, and the dopant is represented by L3M or L2ML′, wherein the M is a transition metal selected from the group consisting of Ir, Pt, Zn and Os, the L and L′ are bidendate ligands coordinated with carbon and nitrogen, and at least one of the L and L′ has 15 or more carbon atoms in the ligand.

1 . An organic electroluminescent display device comprising:
 a substrate;   a first electrode and a second electrode formed on the substrate; and   an organic film layer comprising at least one emitting layer between the first electrode and the second electrode,   wherein the emitting layer comprises at least one phosphorescent dopant represented by the formula L2ML′, wherein the M is a transition metal selected from the group consisting of Ir, and Os, L and L′ are bidendate ligands each coordinated with a carbon and a nitrogen, wherein L and L′ are different from each other and wherein at least one of L and L′ has 15 or more carbon atoms.   
   
   
       2 . The organic electroluminescent display device of  claim 1 , wherein both L and L′ have 15 or more carbon atoms. 
   
   
       3 . The organic electroluminescent display device according to  claim 1 , wherein at least one of the L and L′ has at least two hexagonal ring structures in the ligand. 
   
   
       4 . The organic electroluminescent display device according to  claim 1 , wherein both L and L′ have at least two hexagonal ring structures. 
   
   
       5 . The organic electroluminescent display device according to  claim 1 , wherein the emitting layer comprises subsidiary pixels of a red emitting-layer, a green emitting layer and a blue emitting layer. 
   
   
       6 . The organic electroluminescent display device according to  claim 5 , wherein the blue emitting layer is a fluorescent emitting layer. 
   
   
       7 . The organic electroluminescent display device according to  claim 5 , wherein the blue emitting layer comprises the phosphorescent dopant, and at least one of L and L′ has less than 15 carbon atoms. 
   
   
       8 . The organic electroluminescent display device according to  claim 1 , wherein L and L′ are each independently a compound having a structure represented by one the following chemical formulas 1 to 13 and 15: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
   
   
       9 . The organic electroluminescent display device according to  claim 1 , wherein the phosphorescent dopant represented by the formula L2ML′ is a compound represented by one of the following chemical formulas 16 to 22: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
   
   
       10 . The organic electroluminescent display device according to  claim 1 , wherein the organic film layer further comprises at least one layer selected from a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer and a hole blocking layer. 
   
   
       11 . The organic electroluminescent display device according to  claim 10 , wherein the organic film layer comprises a red emitting layer, a green emitting layer and a blue fluorescent emitting layer, and wherein the hole blocking layer is formed on an upper part of the red emitting layer and the green emitting layer. 
   
   
       12 . The organic electroluminescent display device according to  claim 6 , wherein the blue fluorescent emitting layer is formed on an upper part of the red and green phosphorescent emitting layers I over a front surface of the substrate as a common layer. 
   
   
       13 . The organic electroluminescent display device according to  claim 1 , wherein the second electrode is a cathode electrode if the first electrode is an anode electrode, and the second electrode is an anode electrode if the first electrode is a cathode electrode. 
   
   
       14 . An emitting compound having a chemical structure of L2ML′ wherein M is a transition metal selected from the group consisting of Ir and Os, L and L′ are bidendate ligands each coordinated with a carbon and a nitrogen, wherein L and L′ are different from each other and wherein at least one of L and L′ has 15 or more carbon atoms. 
   
   
       15 . The emitting compound according to  claim 14 , wherein L and L′ are each independently a compound having a structure of the following chemical formulas 1 to 13 and 15: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
   
   
       16 . The emitting compound according to  claim 14 , wherein L2ML′ is a compound selected from compounds represented by the following chemical formulas 16 to 22: