The present disclosure relates in parts to compounds capable of emitting delayed fluorescence and uses of these compounds in organic light-emitting diodes.

The present disclosure relates to compounds of Formula (I) as useful materials for OLED's. X is O or S; Y.sup.1 to Y.sup.4 are N or R—C; at least one of R and R.sup.5 to R.sup.8 is CN or heteroaryl; and at least other one of R and R.sup.5 to R.sup.8 is diarylamino. ##STR00001##

A condensed cyclic compound and an organic light-emitting device including the same are provided. The condensed cyclic compound is represented by Formula 1: ##STR00001##

The present disclosure relates to compounds capable of emitting delayed fluorescence, and uses of the compounds in organic light-emitting diodes.

Provided is a light-emitting element with high external quantum efficiency and a low drive voltage. The light-emitting element includes a light-emitting layer which contains a phosphorescent compound and a material exhibiting thermally activated delayed fluorescence between a pair of electrodes, wherein a peak of a fluorescence spectrum and/or a peak of a phosphorescence spectrum of the material exhibiting thermally activated delayed fluorescence overlap(s) with a lowest-energy-side absorption band in an absorption spectrum of the phosphorescent compound, and wherein the phosphorescent compound exhibits phosphorescence in the light-emitting layer by voltage application between the pair of electrodes.

A novel organic compound is provided. That is, a novel organic compound that is effective in improving reliability of a light-emitting element is provided. The organic compound includes a condensed ring including a pyrimidine ring and is represented by General Formula (G1). In General Formula (G1), A represents a group having 6 to 100 carbon atoms and includes at least one of an aromatic ring and a heteroaromatic ring. The aromatic ring and the heteroaromatic ring may each include a substituent. Furthermore, Q represents oxygen or sulfur. A ring X represents a substituted or unsubstituted naphthalene ring or a substituted or unsubstituted phenanthrene ring.

An organic compound having a naphtho fluoranthene core and a hetero aromatic group bonded to a specific position of the naphtho fluoranthene core, an organic light-emitting diode and an organic light-emitting device including the compound are disclosed. Since the organic compound has a narrow Stokes Shift between an absorption wavelength and an emission wavelength, the organic compound has a broad overlapped area between its absorption peak and an emission peak of a delayed fluorescent material, and therefore it can emit blue light with high color purity. It is possible to manufacture an organic light-emitting diode (OLED) and an organic light-emitting device that enhance luminous efficiency and color purity using the organic compound.

Provided is a light-emitting element with high external quantum efficiency and a low drive voltage. The light-emitting element includes a light-emitting layer which contains a phosphorescent compound and a material exhibiting thermally activated delayed fluorescence between a pair of electrodes, wherein a peak of a fluorescence spectrum and/or a peak of a phosphorescence spectrum of the material exhibiting thermally activated delayed fluorescence overlap(s) with a lowest-energy-side absorption band in an absorption spectrum of the phosphorescent compound, and wherein the phosphorescent compound exhibits phosphorescence in the light-emitting layer by voltage application between the pair of electrodes.

Provided is a light-emitting element including a fluorescence-emitting material with high emission efficiency. The light-emitting element includes a pair of electrodes and an EL layer between the pair of electrodes. The EL layer includes a first organic compound, a second organic compound, and a guest material. The first organic compound has a function of emitting a thermally activated delayed fluorescence at room temperature. The guest material has a function of emitting fluorescence. A HOMO level of the first organic compound higher than or equal to a HOMO level of the second organic compound. A LUMO level of the first organic compound is lower than or equal to a LUMO level of the second organic compound.

A light-emitting element including a fluorescent material as a light-emitting material and having high emission efficiency is provided. The light-emitting element includes a pair of electrodes and an EL layer provided between the pair of electrodes. The EL layer includes a host material and a guest material. The host material is capable of exhibiting thermally activated delayed fluorescence at room temperature. The guest material is capable of exhibiting fluorescence. The second triplet excitation energy level of the guest material is higher than or equal to the lowest singlet excitation energy level of the guest material.