In the organic electroluminescent device having at least an anode, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer and a cathode in this order, the hole injection layer includes an arylamine compound of the following general formula (1) and an electron acceptor.

##STR00001##

In the formula, Ar.sub.1 to Ar.sub.4 may be the same or different, and represent a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, or a substituted or unsubstituted condensed polycyclic aromatic group.

An organic light-emitting element which emits delayed fluorescence comprising specifically substituted 1,2,4-triazole derivatives, 1,2,4-oxadiazole derivatives or 1,2,4-thiadiazole derivatives in the light-emitting layer, a light-emitting layer comprising the specifically substituted 1,2,4-triazole derivatives, 1,2,4-oxadiazole derivatives or 1,2,4-thiadiazole derivatives, specific specifically substituted 1,2,4-triazole derivatives, 1,2,4-oxadiazole derivatives and 1,2,4-thiadiazole derivatives and an organic light emitting element comprising the specific 1,2,4-azole derivatives as well as a light emitting layer comprising the specific 1,2,4-azole derivatives; the use of the specifically substituted 1,2,4-triazole derivatives, 1,2,4-oxadiazole derivatives and 1,2,4-thiadiazole derivatives for electrophotographic photoreceptors, photoelectric converters, sensors, dye lasers, solar cell devices and organic light emitting elements, and the use of the specifically substituted 1,2,4-triazole derivatives, 1,2,4-oxadiazole derivatives and 1,2,4-thiadiazole derivatives for generating delayed fluorescence emission.

Complexes and devices, such as organic light emitting devices and full color displays, including a compound of the formula wherein: M is Pd.sup.2+, Ir.sup.+, Rh.sup.+, or Au.sup.3+; each of V.sup.1, V.sup.2, V.sup.3, and V.sup.4 is coordinated to M and is independently N, C, P, B, or Si; each of L.sup.1, L.sup.2, L.sup.3, and L.sup.4 is independently a substituted or unsubstituted aryl, cycloalkyl, cycloalkenyl, heterocyclyl, heteroaryl, carbene, or N-heterocyclic carbene; and Z is O, S, NR, CR.sub.2, SiR.sub.2, BR, PR, where each R is independently substituted or unsubstituted C1-C4 alkyl or substituted or unsubstituted aryl.

An organic electroluminescent element using a compound represented by the following general formula (I) emits dark blue light and has small changes in the chromaticity and in the driving voltage even after driving for a long period of time: ##STR00001##
wherein R.sup.1 to R.sup.6; Q.sup.1 and Q.sup.2; X.sup.1, X.sup.2, X.sup.3 and X.sup.4 are as defined herein.

An organometallic compound is represented by Formula 1. An organic light-emitting device includes: a first electrode; a second electrode facing the first electrode; an organic layer between the first electrode and the second electrode and comprising an emission layer; and the organometallic compound represented by Formula 1. In Formula 1, each substituent is the same as described herein. ##STR00001##

The invention relates to purely organic molecules according to formula A without metal center and their use as emitters in organic light-emitting diodes (OLEDs) and in other optoelectronic devices

##STR00001##

with Y is independently selected from the group consisting of C, PR, S, and S(═O); W is independently selected from the group consisting of C(CN).sub.2, NR, O, and S; X is selected from the group consisting of CR.sup.2, C═C(CN).sub.2, NR, O, and S; Ar is a substituted aryl or heteroaryl group with 5 to 40 aromatic ring atoms, which is substituted with m same or different radicals R* and with n same or different donor groups D with electron-donating properties, wherein m+n equals the number of substitutable ring atoms and wherein D comprises a structure of formula I:

##STR00002##

wherein A and B are independently selected from the group consisting of CRR′, CR, NR, and N, wherein there is a single of a double bond between A and B and a single or a double bond between B and Z; Z is a direct bond or a divalent organic bridge group selected from the group consisting of a substituted or unsubstituted C1-C9-alkylene group, C2-C8-alkenylene group, C2-C8-alkynylene or arylene group or a combination of these, —CRR′, —C═CRR′, —C═NR, —NR—, —O—, —SiRR′—, —S—, —S(O)—, —S(O).sub.2—, O-interrupted substituted or unsubstituted C1-C9-alkylene, C2-C8-alkenylene, C2-C8-alkynylene or arylene groups, and phenyl or substituted phenyl units; wherein the waved line indicates the position over which D is bound to Ar.

Thermally activated delayed fluorescent compounds and uses thereof are described. The thermally activated delayed fluorescent compounds are an analogues of 9,10-dihydro-9,9-dimethylacridine compounds.

An organic light-emitting device including: a first electrode; a second electrode facing the first electrode; and an organic layer between the first electrode and the second electrode and including an emission layer, wherein the organic layer includes: i) a hole transport region between the first electrode and the emission layer, and including at least one selected from a hole injection layer, a hole transport layer, an emission auxiliary layer, and an electron blocking layer, and ii) an electron transport region between the emission layer and the second electrode and including an electron transport layer, in addition to at least one selected from a hole blocking layer, an electron control layer, a buffer layer, and an electron injection layer, wherein the electron transport region includes a compound represented by Formula 1:

##STR00001##

An organometallic compound represented by Formula 1:

M(L.sub.1)(L.sub.2)  Formula 1 wherein, in Formula 1, M, L.sub.1, and L.sub.2 are the same as described in the specification.

Disclosed is a polycyclic compound that can be employed in various organic layers of an organic electroluminescent device. The polycyclic compound has a characteristic skeleton structure and characteristic substituents. Also disclosed is an organic electroluminescent device including the polycyclic compound. The organic electroluminescent device includes a light emitting layer employing the polycyclic compound as a dopant and an anthracene derivative having a characteristic structure as a host. The use of the polycyclic compound significantly improves the luminous efficiency and life characteristics of the organic electroluminescent device and makes the organic electroluminescent device highly efficient and long lasting.