A light emitting element includes a first electrode, a second electrode disposed on the first electrode, and a light emitting area disposed between the first electrode and the second electrode and including a phosphorescent dopant, a hole transporting host, and an electron transporting host, wherein the light emitting area includes at least one auxiliary light emitting layer including a thermally activated delayed fluorescence dopant, the hole transporting host, and the electron transporting host and spaced apart from the first electrode and the second electrode.

An organic light-emitting device includes: a first electrode; a second electrode facing the first electrode; and an organic layer between the first electrode and the second electrode and comprising a fluorescent emission layer. The fluorescent emission layer includes a first host (H1), a second host (H2), a first dopant (D1), and a second dopant (D2).

Provided are a polycyclic compound represented by Formula 1 and an organic light-emitting device and an electronic apparatus, each including the same.

An organic electronic device, preferably an organic light-emitting diode (OLED), comprising at least one metal-carbene complex comprising one, two or three specific bidentate diazabenzimidazole carbene ligands; a light-emitting layer comprising said metal-carbene complex as emitter material, preferably in combination with at least one host material; the use of said metal-carbene complex in an OLED; an apparatus selected from the group consisting of stationary visual display units, mobile visual display units, illumination units, units in items of clothing, units in handbags, units in accessories, units in furniture and units in wallpaper comprising said organic electronic device, preferably said OLED, or said light-emitting layer; the metal-carbene complex comprising one, two or three specific bidentate diazabenzimidazole carbene ligands mentioned above and a process for the preparation of said metal-carbene complex.

An organic electroluminescent element including a substrate, a pair of electrodes including an anode and a cathode, disposed on the substrate, and at least one organic layer including a light emitting layer, disposed between the electrodes, in which at least one layer of the organic layer(s) contains a compound represented by the following formula, has low driving voltage and excellent durability.

##STR00001##

(X.sup.1 to X.sup.11 represent CR.sup.0 or N, and R.sup.0 represents a hydrogen atom or a substituent. Adjacent two of X.sup.1 to X.sup.11 each independently represent at least CR.sup.0, R.sup.0s of the adjacent two CR.sup.0s are bonded to each other to form a ring, and only one R.sup.0 of the adjacent two CR.sup.0s represents an aryl group or a heteroaryl group.)

The present disclosure provides an organic electroluminescent device including: an anode; a cathode; and one or more organic material layers interposed between the anode and cathode and selected from the group consisting of a hole injection layer, a hole transporting layer, a light emitting layer, an electron transporting layer, and an electron injection layer, and further including a lifetime enhancement layer (LEL) between the light emitting layer and the electron transporting layer.

A composition including a first compound capable of functioning as a phosphorescent emitter in an OLED is provided. The first compound has at least one aromatic ring and at least one substituent R directly bonded to one of the at least one aromatic rings. Each substituent R has the formula of ##STR00001##
where (a) G.sup.1 is selected from NR.sup.1, SiR.sup.1R.sup.2, GeR.sup.1R.sup.2, alkyl, cycloalkyl, and combinations thereof; and G.sup.2 is a non-aromatic polycyclic group; (b) G.sup.1 is a direct bond; and G.sup.2 is a non-aromatic spiro polycyclic group; or (c) G.sup.1 is selected from direct bond, NR.sup.1, SiR.sup.1R.sup.2, GeR.sup.1R.sup.2, alkyl, cycloalkyl, and combinations thereof; G.sup.2 is a non-aromatic polycyclic group; and R is directly bonded to a phenyl, pyridine, or triazine. R.sup.1, R.sup.2, and R.sup.3 are a variety of substituents. Formulations and devices, such as an OLEDs, that include the first compound are also described.

Provided is a heterocyclic compound of Chemical Formula 1:

##STR00001## wherein: X.sub.1 is O or S; L.sub.1 is a single bond or an unsubstituted phenylene; L.sub.2 is a single bond, or a substituted or unsubstituted: phenylene, naphthylene, or biphenylenyl; Y.sub.1 to Y.sub.3 are each independently N or CR.sub.3, where at least one is N; Ar.sub.1a and Ar.sub.1b are each independently a substituted or unsubstituted: C.sub.6-60 aryl or C.sub.1-60 heteroaryl containing 1 to 3 heteroatoms selected from N, O and S; R.sub.1 and R.sub.2 are each independently hydrogen, deuterium, cyano, or a substituted or unsubstituted C.sub.1-10 alkyl; each R.sub.3 is independently hydrogen, deuterium, halogen, cyano, nitro, amino, or a substituted or unsubstituted: C.sub.1-60 alkyl, C.sub.1-60 haloalkyl, C.sub.1-60 alkoxy, a C.sub.1-60 haloalkoxy, C.sub.3-60 cycloalkyl, C.sub.2-60 alkenyl, C.sub.6-60 aryl, C.sub.6-60 aryloxy, or a C.sub.1-60 heteroaryl containing at least one heteroatom selected from N, O and S; and an organic light emitting device comprising the same.

The invention relates to a composition comprising an electron-transporting host and a hole-transporting host, to the use thereof in electronic devices and to electronic devices containing said composition. The electron-transporting host is most preferably selected from the class of triazine-dibenzofurane-fluorenyl systems or from the class of triazine-dibenzothiophene-fluorenyl systems. The hole-transporting host is preferably selected from the class of biscarbazoles.

The invention relates to organic electroluminescence devices containing indone carbazole derivatives.