Disclosed is an organic light emitting diode (OLED) includes a first emitting material layer, which includes a first compound and a second compound, and a second emitting material layer, which includes a third compound and a fourth compound, wherein a HOMO energy level of the first compound is higher than a HOMO energy level of the second compound and a HOMO energy level of the third compound is lower than a HOMO energy level of the fourth compound, and an organic light emitting device having the OLED. The OLED and the organic light emitting device disclosed have enhanced luminous efficiency, color purity and luminous life span as well as low driving voltage by applying the emitting material layer.

A display apparatus according to an embodiment of the present disclosure includes a substrate in which an emission area and a non-emission area are divided and a plurality of sub pixels is defined, a first electrode disposed in each of the plurality of sub pixels, a bank which is disposed on an insulating layer above the substrate and exposes the first electrode through an opening, a trench which is formed by removing a partial area of the bank between the plurality of sub pixels to expose the insulating layer, an organic layer disposed above the substrate in which the bank is disposed, a charge blocking layer interposed in the organic layer in the trench, and a second electrode disposed on the organic layer.

Disclosed is an organic light-emitting device including an emission layer that includes a first compound.

An organic electroluminescence device includes an anode, a cathode, a first emitting layer, and a second emitting layer provided between the first emitting layer and the cathode in which the first emitting layer contains a first compound represented by a formula (1) below as a first host material, the first compound containing at least one group represented by a formula (11) below, the second emitting layer contains a second compound represented by a formula (2) below as a second host material, and the first emitting layer and the second emitting layer are in direct contact with each other.

##STR00001##

Provided is a compound of Chemical Formula 1: ##STR00001## where R.sub.1 and R.sub.2 are each independently hydrogen, a substituted or unsubstituted C.sub.1-60 alkyl, a substituted or unsubstituted C.sub.1-60 alkoxy, a substituted or unsubstituted C.sub.1-60 haloalkyl, a substituted or unsubstituted C.sub.1-60 haloalkoxy, halogen, cyano, tri(C.sub.1-60 alkyl)silyl, a substituted or unsubstituted C.sub.6-60 aryl, or a substituted or unsubstituted C.sub.2-60 heteroaryl containing at least one of O, N, Si and S, R.sub.3 and R.sub.4 are each independently hydrogen, deuterium, a substituted or unsubstituted C.sub.1-60 alkyl, a substituted or unsubstituted C.sub.1-60 alkoxy, a substituted or unsubstituted C.sub.1-60 haloalkyl, a substituted or unsubstituted C.sub.1-60 haloalkoxy, halogen, cyano, tri(C.sub.1-60 alkyl)silyl, or a substituted or unsubstituted C.sub.2-60 heteroaryl containing at least one of O, N, Si and S, and Ar is C.sub.6-60 aryl, or C.sub.2-60 heteroaryl containing at least one of O, N, Si and S, wherein the C.sub.6-60 aryl, or C.sub.2-60 heteroaryl is substituted with 1 to 5 substituents each selected from the group consisting of a substituted or unsubstituted C.sub.1-60 alkyl, a substituted or unsubstituted C.sub.1-60 alkoxy, a substituted or unsubstituted C.sub.1-60 haloalkyl, a substituted or unsubstituted C.sub.1-60 haloalkoxy, halogen, cyano, and tri(C.sub.1-60 alkyl)silyl, and an organic light emitting device including the same.

To increase emission efficiency of a fluorescent light-emitting element by efficiently utilizing a triplet exciton generated in a light-emitting layer. The light-emitting layer of the light-emitting element includes at least a host material and a guest material. The triplet exciton generated from the host material in the light-emitting layer is changed to a singlet exciton by triplet-triplet annihilation (TTA). The guest material (fluorescent dopant) is made to emit light by energy transfer from the singlet exciton. Thus, the emission efficiency of the light-emitting element is improved.

To increase emission efficiency of a fluorescent light-emitting element by efficiently utilizing a triplet exciton generated in a light-emitting layer. The light-emitting layer of the light-emitting element includes at least a host material and a guest material. The triplet exciton generated from the host material in the light-emitting layer is changed to a singlet exciton by triplet-triplet annihilation (TTA). The guest material (fluorescent dopant) is made to emit light by energy transfer from the singlet exciton. Thus, the emission efficiency of the light-emitting element is improved.

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.

An organic electroluminescent device and a display apparatus. The organic electroluminescent device includes a first electrode, a second electrode and at least two organic electroluminescent units located between the first electrode and the second electrode. The at least two organic electroluminescent units are arranged in a stacked manner. The at least two organic electroluminescent units include a first organic electroluminescent unit. The first organic electroluminescent unit includes a first light-emitting layer. The first light-emitting layer contains a first host material, a thermally activated delayed fluorescence sensitizer and a first fluorescent dye.

An organic electroluminescent device and a display apparatus. The organic electroluminescent device includes a first electrode, a second electrode and at least two organic electroluminescent units located between the first electrode and the second electrode. The at least two organic electroluminescent units are arranged in a stacked manner. The at least two organic electroluminescent units include a first organic electroluminescent unit. The first organic electroluminescent unit includes a first light-emitting layer. The first light-emitting layer contains a first host material, a thermally activated delayed fluorescence sensitizer and a first fluorescent dye.