An organic light-emitting device containing a compound having a lone electron pair and a π electron orbital, the compound emitting fluorescent light by such a mechanism that when at least apart of electrons constituting the lone electron pair is excited to an excited triplet state .sup.3nπ* through nπ* transition, the part of electrons undergoes inverse intersystem crossing from the excited triplet state .sup.3nπ* to an excited singlet state .sup.1nπ*, and returns from the excited singlet state .sup.1nπ* to the ground state, at which the fluorescent light is emitted. The organic light-emitting device has a high light emission efficiency.

To provide an electrochromic compound, represented by the following general formula (I), where Ar.sub.1 is a pyridinium ring having a structure represented by the following general formula (IIa), (IIb), or (IIc), where Ar.sub.2 is a monovalent heterocyclic ring which may have a substituent, but Ar.sub.2 is not a pyridinium ring; R.sub.1 to R.sub.8 are each independently a monovalent group which may have a functional group, where the monovalent group may have a substituent; A is a monovalent group which may have a functional group, where the monovalent group may have a substituent; and B.sup.− is a monovalent anion.

##STR00001##

Provided are an organometallic compound, a light-emitting device including the organometallic compound, and an electronic apparatus including the light-emitting device. The light-emitting device includes a first electrode, a second electrode facing the first electrode, and an interlayer disposed between the first electrode and the second electrode. The interlayer includes an emission layer. The emission layer includes a first compound which is the organometallic compound; and a second compound, a third compound, a fourth compound, or any combination thereof. The first compound, the second compound, the third compound, and the fourth compound are different from one another.

A dual host system for OLEDs that contains hole-transporting indolocarbazole and electron-transporting indolocarbazole exhibiting superior performance in the OLEDs is disclosed.

The present invention relates to a compound of a formula (I) or (II), to the use of this compound in an electronic device, and to an electronic device comprising one or more compounds of the formula (I) or (II). The invention furthermore relates to the preparation of the compound of the formula (I) or (II) and to a formulation comprising one or more compounds of the formula (I) or (II).

A tris-type iridium complex in which a ligand having a distinctive nitrogen-containing five-membered heterocyclic skeleton is coordinated is provided. The ligand has a nitrogen-containing five-membered heterocyclic skeleton composed of 2 to 4 nitrogen atoms and one or more carbon atoms. In the skeleton, an aryl group is bonded to a carbon atom on both sides of which nitrogen atoms are positioned, and a tricycloalkyl group having a bridge structure and having 9 or 10 carbon atoms is bonded to one of the two nitrogen atoms positioned on both the sides of the carbon atom. The tricycloalkyl group having a bridge structure and having 9 or 10 carbon atoms may be an adamantyl group or a noradamantyl group.

The present invention relates to a novel indole-based compound having excellent hole injection and transport capabilities, light-emission, and other properties, and to an organic electroluminescent device the luminous efficiency, driving voltage, service life, and other characteristics of which are improved due to containing the compound in one or more organic material layers.

Provided is a metal complex which is excellent in quantum yield and full width at half maximum of a light emission spectrum. The metal complex is represented by the following formula (1):

##STR00001##

wherein M represents an iridium atom or the like, n.sub.1 represents 1 to 3, n.sub.2 represents 0 to 2, X.sup.1 to X.sup.8 represent a carbon atom or the like, R.sup.1 to R.sup.8 represent a hydrogen atom or the like, one of X.sup.a and X.sup.b is a single bond, and the other is a group represented by —CR.sup.11R.sup.12—CR.sup.13R.sup.14—, R.sup.11 to R.sup.14 represent an alkyl group or the like, ring A represents a heteroaromatic ring, and A.sup.1-G.sup.1-A.sup.2 represents an anionic bidentate ligand.

A condensed cyclic compound and an organic light-emitting device including the same are provided. The compound may be represented by the following structure:

##STR00001## wherein X.sub.1 is N or C(R.sub.1), X.sub.2 is N or C(R.sub.2), X.sub.3 is N or C(R.sub.3), X.sub.4 is N or C(R.sub.4), X.sub.5 is N or C(R.sub.5), and X.sub.6 is N or C(R.sub.6), and ring A.sub.1 is a C.sub.5-C.sub.60 carbocyclic group or a C.sub.2-C.sub.60 heterocyclic group, provided that ring A.sub.1 is not a benzene.

Provided are a fluorescent probe, a preparation method therefor and a use thereof. The fluorescent probe sensitively and specifically responds to viscosity, and can be used for the specific fluorescence labeling of proteins as well as in the quantification, detection or kinetic study of proteins and the imaging of cells, tissues and living bodies.