Light-emitting element
First Claim
1. A light-emitting element comprising:
- a first electrode;
a hole-injection layer over the first electrode;
a first layer over the hole-injection layer, the first layer containing a first organic compound which has a hole-transport property;
a light-emitting layer over the first layer, the light-emitting layer containing a phosphorescent compound, the first organic compound, and a second organic compound which has an electron-transport property;
a second layer over the light-emitting layer, the second layer containing the second organic compound;
an electron-injection layer over the second layer; and
a second electrode over the electron-injection layer,wherein the first organic compound and the second organic compound are selected so that an exciplex is formed therebetween, andwherein the phosphorescent compound is an organometallic complex whose absorption originating from a triplet metal-to-ligand charge transfer transition overlaps with an emission of the exciplex.
1 Assignment
0 Petitions
Accused Products
Abstract
A light-emitting element having extremely high efficiency of approximately 25% is provided. The light-emitting element includes a light-emitting layer which contains a phosphorescent guest, an n-type host, and a p-type host, where the light-emitting layer is interposed between an n-type layer including the n-type host and a p-type layer including the p-type host, and where the n-type host and the p-type host are able to form an exciplex in the light-emitting layer. The light-emitting element exhibits an extremely high emission efficiency (power efficiency of 74.3 lm/W, external quantum efficiency of 24.5%, energy efficiency of 19.3%) at a low driving voltage (2.6 V) at which luminance of 1200 cd/m2 is attainable.
183 Citations
12 Claims
-
1. A light-emitting element comprising:
-
a first electrode; a hole-injection layer over the first electrode; a first layer over the hole-injection layer, the first layer containing a first organic compound which has a hole-transport property; a light-emitting layer over the first layer, the light-emitting layer containing a phosphorescent compound, the first organic compound, and a second organic compound which has an electron-transport property; a second layer over the light-emitting layer, the second layer containing the second organic compound; an electron-injection layer over the second layer; and a second electrode over the electron-injection layer, wherein the first organic compound and the second organic compound are selected so that an exciplex is formed therebetween, and wherein the phosphorescent compound is an organometallic complex whose absorption originating from a triplet metal-to-ligand charge transfer transition overlaps with an emission of the exciplex. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
Specification