Organic light emitting display device

Abstract

An organic light emitting display device includes a first electrode and a second electrode disposed on a substrate opposite to each other, a first stack including a hole injection layer, a first hole transport layer, a first light emitting layer, and a first electron transport layer sequentially stacked on the first electrode, a second stack including a second hole transport layer, a second light emitting layer, and a second electron transport layer sequentially stacked between the first stack and the second electrode, and a charge generation layer disposed between the first stack and the second stack and including an N-type charge generation layer and a P-type charge generation layer to control charge balance between the first and second stacks. The P-type charge generation layer is doped with 1% to 20% of a hole transport material based on a volume of the P-type charge generation layer.

What is claimed is: 
     
       1. An organic light emitting display device comprising:
 a first electrode and a second electrode disposed on a substrate opposite to spaced from each other; 
 a first stack comprising a hole injection layer, a first hole transport layer, a first light emitting layer, and a first electron transport layer sequentially stacked on the first electrode; 
 a second stack comprising a second hole transport layer, a second light emitting layer, and a second electron transport layer sequentially stacked between the first stack and the second electrode; and 
 a charge generation layer disposed between the first stack and the second stack and comprising an at least one N-type charge generation layer and at least one P-type charge generation layerto control charge balance between the first and second stacks, 
 wherein the at least one P-type charge generation layer is composed of HAT(CN)6 doped with 1% to 20% 10% of a hole transport material based on a volume of the at least one P-type charge generation layer, wherein the hole transport material has a highest occupied molecular orbital (HOMO) level of 5.0 eV to 6.0 eV; and 
 wherein a thickness of a region in which the hole transport material is doped satisfies Expression 1 below to be at least 10% or greater of a total thickness of the at least one P-type charge generation layer:
   L×0.1≤X≤L,  Expression 1
 
 
 where L is a thickness of the at least one P-type charge generation layer, and X is a thickness of the region in which the hole transport material is doped. 
 
     
     
       2. The organic light emitting display device according to  claim 1 , wherein the hole transport material doped in the at least one P-type charge generation layer has a mobility of 5.0×10 −5  cm 2 /Vs to 1.0×10 −2  cm 2 /Vs. 
     
     
       3. The organic light emitting display device according to  claim 1 , wherein the hole transport material doped in the at least one P-type charge generation layer has a lowest unoccupied molecular orbital (LUMO) level of 2.0 eV to 3.5 eV. 
     
     
       4. The organic light emitting display device according to  claim 1 , wherein the hole transport material doped in the at least one P-type charge generation layer has a mobility of 9.0×10 −3  cm 2 /Vs, a LUMO level of 2.1 eV, and a HOMO level of 5.2 eV. 
     
     
       5. The organic light emitting display device according to  claim 1 , wherein the hole transport material doped in the at least one P-type charge generation layer has a mobility of 6.0×10 −4  cm 2 /Vs, a LUMO level of 2.3 eV, and a HOMO level of 5.5 eV. 
     
     
       6. The organic light emitting display device according to  claim 1 , wherein a thickness of a region in which the hole transport material is doped satisfies Expression 1 below to be a 10% or greater thickness of a total thickness of in the at least one P-type charge generation layer has a mobility of 6.0×10 −4  cm 2 /Vs, a LUMO level of 2.3 eV, and a HOMO level of 5.6 eV. 
     
     
       7. The original light emitting display device according to  claim 1 , further comprising a buffer layer between the at least one P-type charge generation layer doped with the hole transport layer and the N-type charge generation layer. 
     
     
       8. The organic light emitting display device according to  claim 1 , wherein the second hole transport layer of the second stack is formed by co-depositing same material included in the at least one P-type charge generation layer doped with the hole transport layer and material is also included in the second hold hole transport layer of the second stack. 
     
     
       9. The organic light emitting display device according to  claim 1 , wherein the at least one P-type charge generation layer comprises:
 a first P-type charge generation layer; and   a second P-type charge generation layer comprising a host identical to the material used to form the first P-type charge generation layer and a dopant comprising the hole transport material, and   wherein the second P-type charge generation layer is included as a layer in the at least one P-type charge generation layer.   
     
     
       10. The organic light emitting display device according to  claim 9 , wherein at least one layer of the second P-type charge generation layer is doped with a dopant comprising a hole transport material identical to a hole transport material of another layer of the second P-type charge generation layer. 
     
     
       11. The organic light emitting display device according to  claim 9 , wherein at least one layer of the second P-type charge generation layer is doped with a dopant comprising a hole transport material different from a hole transport material of another layer of the second P-type charge generation layer. 
     
     
       12. The organic light emitting display device according to  claim 9 , wherein at least one layer of the second P-type charge generation layer is doped at the same doping concentration from another layer of the second P-type charge generation layer. 
     
     
       13. The organic light emitting display device according to  claim 9 , wherein at least one layer of the second P-type charge generation layer is doped at a different doping concentration from another layer of the second P-type charge generation layer. 
     
     
       14. The organic light emitting display device according to  claim 1 , further comprising another hole transport layer comprising a different hole transport material from the material of the first hole transport layer, the another hole transport layer being positioned between the first hole transport layer and the first light emitting layer in the first stack. 
     
     
       15. The organic light emitting display device according to  claim 1 , further comprising another hole transport layer comprising a different hole transport material from the material of the second hole transport layer, the another hole transport layer being positioned between the second hole transport layer and the second light emitting layer in the second stack. 
     
     
       16. The organic light emitting display device according to  claim 1 , further comprising a third stack comprising a hole transport layer, a light emitting layer, and an electron transport layer stacked between the second stack and the second electrode. 
     
     
       17. An organic light emitting display device comprising:
 a first electrode and a second electrode on a substrate and spaced from each other;   a first stack comprising a hole injection layer, a first hole transport layer, a first light emitting layer, and a first electron transport layer on the first electrode;   a second stack comprising a second hole transport layer, a second light emitting layer, and a second electron transport layer, the second stack being positioned between the first stack and the second electrode; and   a charge generation layer between the first stack and the second stack and comprising an N-type charge generation layer and at least one P-type charge generation layer positioned between the first and second stacks,   wherein the at least one P-type charge generation layer is composed of HAT(CN)6 doped with 1% to 10% of a hole transport material based on a volume of the at least one P-type charge generation layer,   wherein the hole transport material has a highest occupied molecular orbital (HOMO) level of 5.0 eV to 6.0 eV and a lowest unoccupied molecular orbital (LUMO) level of 2.0 eV to 3.5 eV; and   wherein the hole transport material doped in the at least one P-type charge generation layer has a thickness satisfying the expression of:
   L×0.1≤X≤L,
 
   wherein L is a thickness of the at least one P-type charge generation layer, and X is a thickness of the hole transport material doped in the at least one P-type charge generation layer.   
     
     
       18. The organic light emitting display device according to  claim 17 , wherein the hole transport material doped in the at least one P-type charge generation layer has a mobility within the range of 5.0×10 −5  cm 2 /Vs to 1.0×10 −2  cm 2 /Vs. 
     
     
       19. The organic light emitting display device according to  claim 17 , wherein the at least one P-type charge generation layer comprises a first P-type charge generation layer; and a second P-type charge generation layer having a host material that is the same material used to form the first P-type charge generation layer and a dopant. 
     
     
       20. The organic light emitting display device according to  claim 17 , wherein the at least one P-type charge generation layer comprises a first P-type charge generation layer and a second P-type charge generation layer, the second P-type generation layer including a host having the same material used to form the first P-type charge generation layer and a dopant of the hole transport material,
 wherein the second P-type charge generation layer is a layer in a multi-layer structure of the at least one P-type charge generation layer, and   wherein at least one layer among the multi-layer structure of the second P-type charge generation layer is doped with a dopant having a second hole transport material.   
     
     
       21. The organic light emitting display device according to  claim 20 , wherein the second hole transport material is different from a third hole transport material of another layer among the multi-layer structure of the second P-type charge generation layer. 
     
     
       22. The organic light emitting display device according to  claim 17 , wherein the at least one P-type charge generation layer comprises a first P-type charge generation layer and a second P-type charge generation comprising host identical to the material used to form the first P-type charge generation layer and a dopant of the hole transport material,
 wherein the second P-type charge generation layer is included as a multi-layer structure in the at least one P-type charge generation layer, and   wherein at least one layer among the multi-layer structure of the second P-type charge generation layer is doped at a different doping concentration from another layer among the multi-layer structure of the second P-type charge generation layer.   
     
     
       23. The original light emitting display device according to  claim 17 , further comprising a buffer layer between the at least one P-type charge generation layer doped with the hole transport material and the N-type charge generation layer. 
     
     
       24. The organic light emitting display device according to  claim 17 , wherein at least one material constituting the at least one P-type charge generation layer is included in the second hole transport layer of the second stack. 
     
     
       25. The organic light emitting display device according to  claim 17 , further comprising a third hole transport layer between the first hole transport layer and the first light emitting layer and a fourth hole transport layer between the second hole transport layer and the second light emitting layer, wherein the third hole transport layer has a different hole transport material from the first hole transport layer and the fourth hole transport layer has a different hole transport material from the second hole transport layer. 
     
     
       26. The organic light emitting display device according to  claim 17 , further comprising a third stack having a hole transport layer, a light emitting layer, and an electron transport layer, third stack being positioned between the second stack and the second electrode. 
     
     
       27. An organic light emitting display device comprising:
 a substrate;   a plurality of transistors positioned on the substrate;   a first electrode positioned on the substrate and above at least one transistor of the plurality of transistors;   a second electrode on a substrate and on the first electrode, the second electrode being spaced from the first electrode;   a first stack positioned between the first and second electrodes, the first stack comprising a hole injection layer, a first hole transport layer, a first light emitting layer, and a first electron transport layer; and   a charge generation multilayer positioned between the first and second electrodes, the charge generation multilayer layer including an N-type charge generation layer and a P-type charge generation layer,   wherein the P-type charge generation layer includes HAT(CN)6 doped with a hole transport material at a volume of 1% to 10% based on a volume of the at least one P-type charge generation layer,   wherein the hole transport material has a highest occupied molecular orbital (HOMO) level of 5.0 eV to 6.0 eV; and   wherein the hole transport material doped in the P-type charge generation layer has a thickness that is at least 10% or greater of a total thickness of the P-type charge generation layer.   
     
     
       28. The organic light emitting display device of  claim 27 , wherein the charge generation multilayer is positioned between the first electrode and the first stack. 
     
     
       29. The organic light emitting display device of  claim 27 , wherein the charge generation multilayer is positioned between the first stack and the second electrode. 
     
     
       30. The organic light emitting display device of  claim 27 , further comprising a second stack and a third stack positioned between the first stack and the second electrode, the second stack comprising a second hole transport layer, a second light emitting layer, and a second electron transport layer, a third stack comprising a third hole transport layer, a third light emitting layer and a third electron transport layer. 
     
     
       31. The organic light emitting display device of  claim 30 , wherein the charge generation multilayer is positioned at least one between the first stack and the second stack, and between the second stack and the third stack. 
     
     
       32. The organic light emitting display device according to  claim 30 , wherein the P-type charge generation layer is in contact with the second hole transport layer and
 wherein the hole transport material doped in the P-type charge generation layer has the same HOMO level as a HOMO level of the second hole transport layer and a same LUMO level as a LUMO level of the second hole transport layer.   
     
     
       33. The organic light emitting display device according to  claim 27 , wherein the hole transport material doped in the P-type charge generation layer has a mobility of 5.0×10 −5  cm 2 /Vs to 1.0×10 −2  cm 2 /Vs.