Organic electroluminescence device

Abstract

An organic electroluminescence device including a lower electrode disposed on a substrate, an organic layer having at least a light emission layer and disposed above the lower electrode, and upper electrode having a transparent conductive film and disposed above the organic layer, in which the device has an electron injecting layer between the organic layer and the upper electrode. The electron injecting layer has a buffer layer comprising an insulative material and a mixed layer comprising an organic material that has an electron transporting property and a metal material that has an electron injecting property.

What is claimed is: 
     
         1 . A display device comprising:
 a plurality of light emission units laminated between a lower electrode and an upper electrode, where each light emission unit comprises at least an organic light emission layer; and   a connection layer is between the respective light emission units,   wherein,
 the organic light emission layer in each light emission unit includes a hole injection layer, a hole transporting layer, a light emission layer, an electron transporting layer in direct succession in the recited order, beginning on the lower electrode, 
 the connection layer having a laminate part comprising (1) a buffer layer of a thickness of 1 nm or less in contact with the organic light emission layer, the buffer layer (a) employing an oxide which contains at least one of an alkali metal and an alkaline-earth metal, and (b) the buffer layer having a hole blocking property resulting from disposing the buffer layer in contact with the organic light emission layer, (2) a mixed layer employing a charge transporting organic material having an electron transporting property and a metal material having an electron injecting property, the mixed layer being composed of the same material as the electron transporting layer in the organic light emission layer, the metal material reacts while reducing the charge transporting organic material to become transparent to ensure the electron injecting property, and (3) a protective layer employing at least one of triphenylene derivatives and azatriphenylene derivatives, the protective layer is oxidized to become light permeable to prevent oxidation of the mixed layer, are successively laminated from the lower electrode side in direct succession. 
   
     
     
         2 . The display device according to  claim 1 , wherein the charge transporting organic material constituting the connection layer is an electron transporting organic material. 
     
     
         3 . The display device according to  claim 2 , wherein the mixed layer employing a charge transporting organic material comprises only an electron transporting organic material. 
     
     
         4 . The display device according to  claim 1 , wherein the charge transporting organic material within the connection layer is a hole transporting organic material. 
     
     
         5 . The display device according to  claim 4 , wherein the buffer layer, the mixed layer, and the protective layer were deposited successively utilizing vapor deposition. 
     
     
         6 . The display device according to  claim 1 , wherein the buffer layer confines holes to the organic light emission layer. 
     
     
         7 . The display device according to  claim 1 , wherein the layer employing an oxide constitutes a boundary layer on the lower electrode side in the connection layer. 
     
     
         8 . The display device according to  claim 1 , wherein the oxide is at least one selected from the group consisting of Li 2 Si0 3 , Li 2 C0 3 , Cs 2 C0 3 , Li 2 W0 4  and SrO. 
     
     
         9 . A display device comprising in order a lower electrode, a light emission layer, a buffer layer, and an upper electrode, wherein the buffer layer includes ytterbium (Yb). 
     
     
         10 . The light emission layer according to any one of  claim 1 , wherein the light emission layer is also configured to be an electron transporting light emission layer. 
     
     
         11 . The light emission layer according to any one of  claim 1 , wherein the light emission layer is also configured to be a hole transporting light emission layer.