Organic light-emitting device

Abstract

An organic light-emitting device (OLED) which exhibits superior light extraction efficiency due to an extraction structure for dipole light generated from an organic light-emitting layer. The OLED includes a first glass substrate, a first electrode disposed on the first glass substrate, an organic light-emitting layer disposed on the first electrode, a second electrode disposed on the organic light-emitting layer, and a second glass substrate disposed on the second electrode. The second electrode has a composite electrode structure including a first transparent electrode layer and a second transparent electrode layer stacked on each other, the refractive index of the second transparent electrode layer being higher than the refractive index of the first transparent electrode layer.

What is claimed is: 
     
         1 . An organic light-emitting device comprising:
 a first glass substrate;   a first electrode disposed on the first glass substrate;   an organic light-emitting layer disposed on the first electrode;   a second electrode disposed on the organic light-emitting layer; and   a second glass substrate disposed on the second electrode,   wherein the second electrode has a composite electrode structure including a first transparent electrode layer and a second transparent electrode layer stacked on each other, a refractive index of the second transparent electrode layer being higher than a refractive index of the first transparent electrode layer.   
     
     
         2 . The organic light-emitting device according to  claim 1 , wherein the first transparent electrode layer is disposed at a side of the second glass substrate, and the second transparent electrode layer is disposed at a side of the organic light-emitting layer. 
     
     
         3 . The organic light-emitting device according to  claim 2 , wherein the refractive index of the second transparent electrode layer ranges from 2.1 to 2.5. 
     
     
         4 . The organic light-emitting device according to  claim 3 , wherein the second transparent electrode layer comprises Al- or Ga-doped ZnO or Nb-doped TiO 2 . 
     
     
         5 . The organic light-emitting device according to  claim 4 , wherein the first transparent electrode layer comprises indium tin oxide. 
     
     
         6 . The organic light-emitting device according to  claim 1 , wherein a thickness of the second electrode ranges from 50 to 200 nm. 
     
     
         7 . The organic light-emitting device according to  claim 1 , comprising a plurality of the organic light-emitting layers which each alternate with interconnecting layers to form a tandem structure. 
     
     
         8 . An organic light-emitting device comprising:
 a first glass substrate;   a first electrode disposed on the first glass substrate;   an organic light-emitting layer disposed on the first electrode;   a second electrode disposed on the organic light-emitting layer, wherein the second electrode has a composite electrode structure including a first transparent electrode layer and a second transparent electrode layer stacked on each other, a refractive index of the second transparent electrode layer being higher than a refractive index of the first transparent electrode layer;   a light extraction layer disposed on the second electrode; and   a second glass substrate disposed on the light extraction layer.   
     
     
         9 . The organic light-emitting device according to  claim 8 , wherein the light extraction layer comprises:
 a matrix layer; and   at least one light-scattering body disposed inside the matrix layer, the light-scattering body being made of a material, a refractive index of which is higher than a refractive index of the matrix layer.   
     
     
         10 . The organic light-emitting device according to  claim 9 , wherein the refractive index of the light-scattering body is higher than the refractive index of the first transparent electrode layer. 
     
     
         11 . The organic light-emitting device according to  claim 10 , wherein the first transparent electrode layer is disposed at a side of the light extraction layer, and the second transparent electrode layer is disposed at a side of the organic light-emitting layer. 
     
     
         12 . The organic light-emitting device according to  claim 11 , wherein the light-scattering body is disposed inside a portion of the matrix layer that adjoins to the first transparent electrode layer. 
     
     
         13 . The organic light-emitting device according to  claim 8 , wherein the refractive index of the second transparent electrode layer ranges from 2.1 to 2.5. 
     
     
         14 . The organic light-emitting device according to  claim 13 , the second transparent electrode layer comprises Al- or Ga-doped ZnO or Nb-doped TiO 2 . 
     
     
         15 . The organic light-emitting device according to  claim 14 , wherein the first transparent electrode layer comprises indium tin oxide. 
     
     
         16 . The organic light-emitting device according to  claim 8 , wherein a thickness of the second electrode ranges from 50 to 200 nm. 
     
     
         17 . The organic light-emitting device according to  claim 8 , comprising a plurality of the organic light-emitting layers which each alternate with interconnecting layers to form a tandem structure.