A light emitting device includes a first electrode, a hole transporting layer in contact with the first electrode, a second electrode, an electron transporting layer in contact with the second electrode; and an emissive layer between the hole transporting layer and the electron transporting layer. The emissive layer includes a metal-assisted delayed fluorescent (MADF) emitter, a fluorescent emitter, and a host, and the MADF emitter harvests electrogenerated excitons and transfers energy to the fluorescent emitter.

An organic light-emitting device including: a first electrode; a second electrode facing the first electrode; a first emission unit and a second emission unit between the first electrode and the second electrode; and a first charge generation layer between the first emission unit and the second emission unit; wherein the first emission unit includes a first emission layer and a first inorganic buffer layer, and the second emission unit includes a second emission layer and a second inorganic buffer layer.

The present invention relates to organic light emitting devices with a multi-emissive material layer (EML), where a multi-EML generally refers to an emissive layer having at least two layers of emissive material, each layer having a different emitter concentration (e.g. a first EML in direct contact with a second EML, and the emitter concentration of the first EML (hole favorable) exceeds that of the second EML (electron favorable)).

A light emitting element that includes a first electrode, a second electrode on the first electrode, and an emission layer between the first electrode and the second electrode is provided. The emission layer includes an organometallic compound represented by Formula 1. The light emitting element has a reduced driving voltage, emits light having an increased color purity, and exhibits a high efficiency and a long lifespan.

##STR00001##

A metal complex is disclosed. In an embodiment a metal complex includes at least one metal atom M and at least one ligand L attached to the metal atom M, wherein the ligand L has the following structure: ##STR00001## wherein E.sup.1 and E.sup.2 are oxygen, wherein the substituent R.sup.1 is selected from the group consisting of branched or unbranched, fluorinated aliphatic hydrocarbons with 1 to 10 C atoms, wherein n=1 to 5, wherein the substituent R.sup.2 is selected from the group consisting of branched or unbranched aliphatic hydrocarbons with 1 to 10 C atoms, aryl and heteroaryl, wherein m>0 to at most 5−n, and wherein the metal M is a main group metal of groups 13 to 15 of the periodic table of elements.

An organic light-emitting device including: a first electrode; a second electrode facing the first electrode; a first emission unit and a second emission unit between the first electrode and the second electrode; and a first charge generation layer between the first emission unit and the second emission unit; wherein the first emission unit includes a first emission layer and a first inorganic buffer layer, and the second emission unit includes a second emission layer and a second inorganic buffer layer.

The present invention includes novel organic materials comprising indolo[2,3-c]carbazole linked to an aromatic heterocycle via a carbazole linker. These materials may be useful as host materials for PHOLED devices.

A multicolor light-emitting element using fluorescence and phosphorescence, which has a small number of manufacturing steps owing to a relatively small number of layers to be formed and is advantageous for practical application can be provided. In addition, a multicolor light-emitting element using fluorescence and phosphorescence, which has favorable emission efficiency is provided. A light-emitting element which includes a light-emitting layer having a stacked-layer structure of a first light-emitting layer exhibiting light emission from a first exciplex and a second light-emitting layer exhibiting phosphorescence is provided.

Platinum, palladium, and gold complexes suitable for use as phosphorescent emitters or as delayed fluorescent and phosphorescent emitters having one of the following structures:

##STR00001## ##STR00002##

The present invention includes novel compounds containing heterocycles or azaheterocycles and fused phenylene or aza and cyano substituted variants thereof. These compounds may be useful as host materials for phosphorescent electroluminescent devices. In some embodiments, the invention includes compounds of Formula I: ##STR00001##