An organic compound is disclosed comprising: a first chemical moiety with a structure of formula I

##STR00001##

and two second chemical moieties, independently from another with a structure of formula II,

##STR00002##

wherein the first chemical moiety is linked to each of the two second chemical moieties via a single bond.

Disclosed herein are an organic light emitting diode including: at least two light emitting stacks interposed between an anode and a cathode and including at least one light emitting material layer; and a charge generation layer interposed between the light emitting stacks. The charge generation layer includes an N-type charge generation layer and a P-type charge generation layer, wherein the N-type charge generation layer and the P-type charge generation layer are stacked in such direction for the N-type charge generation layer to face the anode and for the P-type charge generation layer to face the cathode. The N-type charge generation layer includes a compound represented by Formula 1. The P-type charge generation layer includes any one selected from the group consisting of a compound represented by Formula 2, a compound represented by Formula 3, and a combination thereof. The material for N-type charge generation layers and the material for P-type charge generation layers of the disclosure can secure low driving voltage and long lifespan of an organic light emitting diode when used in the organic light emitting diode. Compounds of Formulae 1, 2, and 3 are as defined herein.

An organic electroluminescent device includes an organic functional layer which is provided between a light emitting layer and an electron transport region, and has a refractive index equal to or greater than the refractive index of the corresponding light emitting layer. The organic electroluminescent device simultaneously exhibits high luminous efficiency, low driving voltage, long service life, and the like.

A light-emitting element includes at least: an anode; a cathode; a light-emitting layer between the anode and the cathode; and a hole-transport layer between the anode and the light-emitting layer. The hole-transport layer is a film containing a mixture of a hole-transport material and a polysiloxane-based polymer. The light-emitting element further includes: a first electron-transport layer between the light-emitting layer and the cathode; and a second electron-transport layer between the first electron-transport layer and the cathode. A value of a LUMO level of the first electron-transport layer is as high as, or higher than, a value of a LUMO level of the second electron-transport layer, and the value of the LUMO level of the first electron-transport layer is higher than a value of a LUMO level of the light-emitting layer in contact with the first electron-transport layer.

An organometallic compound, represented by Formula 1:

M.sub.1(Ln.sub.1).sub.n1(Ln.sub.2).sub.n2  Formula 1

wherein, Ln.sub.1 is a ligand represented by Formula 1-1, Ln.sub.2 is a ligand represented by Formula 2-1 or 2-2, n1 is 1, 2, or 3, and n2 is 0, 1, or 2,

##STR00001##

wherein CY.sub.1 is a benzoquinoline group or a benzoisoquinoline group, X.sub.31 and X.sub.32 are each independently O or S; R.sub.10, R.sub.21 to R.sub.28, R.sub.31 to R.sub.37, R.sub.41 to R.sub.44, and b10 are as defined herein; and * and *′ each indicate a binding site to M.sub.1.

The present specification relates to a heterocyclic compound represented by Chemical Formula 1, and an organic light emitting device comprising the same.

An objective of the disclosure is to provide an organic light-emitting composite material based on an exciplex, which, when used as a light-emitting layer, can enhance the efficiency of an organic electroluminescent device. The disclosure also relates to an organic light-emitting device comprising the organic light-emitting composite material, and use of the organic light-emitting composite material of the disclosure for an organic electron device.

Embodiments of the disclosed subject matter provide an organic light emitting diode (OLED) having an anode, a cathode, an emissive layer disposed between the anode and the cathode, and a hole blocking layer disposed between the emissive and the cathode. The emissive layer may include a phosphorescent dopant, where the phosphorescent dopant has an emission in 0.5% doped PMMA (Poly(methyl methacrylate)) thin film with a peak maximum wavelength that is greater than or equal to 600 nm at room temperature. The energy of a highest occupied molecular orbital (HOMO) of the phosphorescent dopant may be lower than or equal to −5.1 eV, and the energy of the HOMO of the hole blocking layer is at least 0.1 eV lower than the energy of the HOMO of the phosphorescent dopant.

An organic light emitting diode including a plurality delayed fluorescent materials with specific energy levels and an organic light emitting device including the diode is disclosed. When the plurality delayed fluorescent materials with specific energy levels are applied in an emitting material layer, it is possible to minimize the energy loss or exciton quenching during luminous process and to prevent the diode from reducing life span caused by the exciton quenching. When the emitting material layer includes other luminous material having a narrow FWHM, the organic light emitting diode can enhance its color purity.

Provided are an organic light emitting device and a display apparatus. An organic light emitting device, including an anode, a cathode, and an emitting layer disposed between the anode and the cathode; wherein a hole transport layer and an electron blocking layer are disposed between the anode and the emitting layer; the hole transport layer and the electron blocking layer satisfy:

|HOMO.sub.HTL−HOMO.sub.EBL|≤0.2 eV wherein HOMO.sub.HTL is a highest occupied molecular orbital, HOMO energy level of the hole transport layer and HOMO.sub.EBL is a HOMO energy level of the electron blocking layer.