Color stable organic light emitting diode stack
AssigneeUniversal Display Corporation
InventorsHitoshi Yamamoto, Xin Xu, Michael S. Weaver, Vadim Adamovich
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Abstract
The present invention relates to OLED devices and stacks for OLED devices that include a symmetric emissive-layer architecture. In one embodiment, the present invention relates to an emissive stack having three layers, wherein the top and bottom layers emit light in the same or similar color region while the middle layer emits light in a different color region than the other two layers. In such an embodiment, the three layers are in contact with each other with no other layers in between. The symmetric emissive-layer architecture of the present invention can be used to improve the color stability of OLED devices.
Claims19
An organic light emitting device, comprising:
- a first electrode;
- a first emissive stack disposed over the first electrode;
- and
- a second electrode disposed over the first emissive stack;
- wherein the first emissive stack consists of N emissive layers in contact and in sequence from the first electrode side;
- wherein N is an integer of at least 3;
- wherein the first emissive layer in the first emissive stack nearest the first electrode and the Nth emissive layer in the first emissive stack nearest the second electrode emit light in the same color region and differ in at least one of the following properties:
- doping concentration of emissive material, layer thickness, and emissive material,
- wherein at least one of the emissive layers between the first emissive layer and the Nth emissive layer has a thickness that is at least five times the thickness of the first emissive layer, and
- wherein at least one emissive layer in the first emissive stack other than the first and the Nth emissive layers emits light in a different color region than the first and the Nth emissive layers.
Dependencies are inferred from the claim text.