A delayed fluorescence material containing a mixture of an acceptor compound and a donor compound that satisfies the following formulae (1) to (4):
T.sub.1.sup.A−S.sub.1>0.2 eV  (1)
T.sub.1.sup.D−S.sub.1≧0.2 eV  (2)
|LUMO.sup.A|>2.0 eV  (3)
|HOMO.sup.D|≦5.3 eV  (4)
wherein T.sub.1.sup.A represents the excited triplet energy of the acceptor compound; T.sub.1.sup.D represents the excited triplet energy defined of the donor compound; S.sub.1 represents the excited singlet energy of the exciplex; LUMO.sup.A represents the energy level of LUMO of the acceptor compound; and HOMO.sup.D represents the energy level of HOMO of the donor compound.

An organic electroluminescent element includes a hole injection layer (HI), a first hole transport layer (HT1), a second hole transport layer (HT2), and a light-emitting layer containing a host compound (H) and a phosphorescence emitting dopant compound (D), which are laminated in this order, between and an anode and a cathode. The phosphorescence emitting dopant compound has a partial structure represented by Formula (1): ##STR00001## The “highest occupied molecular orbital” HOMO of the second hole transport layer satisfies the expression: −5.4<HOMO (HT2)<−4.8; and the relationship of triplet excitation energies (T1) between the phosphorescence emitting dopant compound and a hole transport material contained in the second hole transport layer satisfies the expression: T1 (HT2)−T1 (D)>0.1.

A specific nitrogen-containing heterocyclic compound having a urea structure, an electron transporting material containing the nitrogen-containing heterocyclic compound, and an organic electroluminescence device including a light emitting layer and an electron transporting layer between a cathode and an anode in which the electron transporting layer includes the electron transporting material or the nitrogen-containing heterocyclic derivative. An organic EL device exhibiting high emission efficiency even at low voltage and a material for organic EL devices are described.

Novel phosphorescent tetradentate platinum compounds of Formula I are provided. The complexes contain a dibenzo moiety, which allows for the creation of OLED devices with improved properties when compounds of Formula I are incorporated into such devices. Compounds of Formula I′ that comprise two ligands that contain a 5-membered carbocyclic or heterocyclic ring, one of which contains an imidazole ring with a twisted aryl group attached to N−1 and a second aromatic ring that is attached to the platinum via a carbon atom. These compounds may be advantageously used in OLEDs.

An aromatic amine derivative represented by the following formula (1) wherein at least one of Ar.sub.1 to Ar.sub.4 is a heterocyclic group represented by the following formula (2) wherein X.sub.1 is an oxygen atom or a sulfur atom. ##STR00001##

The present invention relates to copolymers containing indenocarbazole derivatives having electron- and hole-transporting properties, in particular for use in the interlayer, emission layer and/or charge-transport layer of electroluminescent devices. The invention furthermore relates to a process for the preparation of the compounds according to the invention and to electronic devices comprising these compounds.

Provided are a substrate for an organic electronic device (OED) and a use thereof. Provided is a substrate for a device having excellent durability by preventing interlayer delamination occurring due to internal stress in a structure in which an organic material and an inorganic material are mixed. In addition, provided is an OED having another required physical property such as excellent light extraction efficiency using the substrate, as well as the excellent durability.

An organometallic complex represented by Formula 1 below and an organic light-emitting device including the same: ##STR00001##
Formula 1 is as defined in the specification.

A metal complex exhibits blue light emission of high color purity and has a color purity of small temperature dependence, particularly in the blue region. Specifically, the metal complex is represented by Formula (1a): ##STR00001##
wherein M is a metal atom; R.sup.0 is a divalent linking group; each j independently represents 0 or 1; R.sup.P1, R.sup.P2, R.sup.P3, R.sup.P4 and R.sup.P6 each independently represents a hydrogen atom or the like; R.sup.P5 represents a halogen atom or the like; m is an integer of from 1 to 3, n is an integer of from 0 to 2, and m+n is 2 or 3; and the portion represented by Formula (2): ##STR00002##
represents a bidentate ligand; wherein R.sup.x and R.sup.y are an atom bonding to the metal atom M, and each independently represents a carbon atom, an oxygen atom or a nitrogen atom.

There is provided a compound having Formula I ##STR00001##
In the formula: R.sup.1 can be aryl, alkyl, silyl, or deuterated analogs thereof; R.sup.2 can be aryl, alkyl, silyl, or deuterated analogs thereof; R.sup.3 can be H, D, alkyl, silyl, deuterated alkyl, or deuterated silyl; and R.sup.4 is the same or different at each occurrence and is H, D, aryl, alkyl, silyl, deuterated aryl, deuterated alkyl, or deuterated silyl.