Organic electroluminescent devices

摘要

An OLED having an organic layer formed of a dopant and a host, where the organic layer is disposed between an anode and a cathode is disclosed. The dopant's concentration level in the organic layer, along a direction perpendicular to the first and second planar surfaces of the organic layer, defines a novel concentration gradient that enhances the OLED's efficiency.

主权项

1. A device comprising one or more organic light emitting devices, at least one of the organic light emitting devices comprising:
an anode; a cathode that is parallel to the anode; and a first organic layer disposed between the anode and the cathode and having a first planar surface and a second planar surface that are parallel to the anode and the cathode and defining a perpendicular distance L, representing the thickness of the first organic layer, between the first planar surface and the second planar surface, wherein the anode is closer to the first planar surface than the second planar surface;
wherein the first organic layer comprises a dopant material and a host material;wherein the dopant material has a concentration level in the first organic layer that is between 0.1 to 90 wt. % and is generally constant throughout the first organic layer along a direction parallel to the first and second planar surfaces;wherein the dopant material's concentration level in the first organic layer along a direction perpendicular to the first and second planar surfaces, is not generally constant and defines a first concentration gradient along the direction perpendicular to the first and second planar surfaces;wherein the first concentration gradient has a first concentration level C1 within a distance of no more than 0.1 L from the first planar surface, a second concentration level C2 within a distance of no more than 0.1 L from the second planar surface, and a third concentration level C3 at a distance less than 0.5 L but greater than 0.1 L from the first planar surface, wherein the third concentration level C3 is greater than the first concentration level C1 and the second concentration level C2.