A multicolor light-emitting element using fluorescence and phosphorescence, which has a small number of manufacturing steps owing to a relatively small number of layers to be formed and is advantageous for practical application can be provided. In addition, a multicolor light-emitting element using fluorescence and phosphorescence, which has favorable emission efficiency is provided. A light-emitting element which includes a light-emitting layer having a stacked-layer structure of a first light-emitting layer exhibiting light emission from a first exciplex and a second light-emitting layer exhibiting phosphorescence is provided.

A light emitting device is capable of improving the efficiency in the visible light wavelength in a structure in which light extraction efficiency is improved through a microlens array. The light emitting display device includes a substrate having a plurality of subpixels, each comprising a light emitting region and a non-light emitting region, an over-coating layer having irregularities on a surface thereof in at least the light emitting region, and a light emitting device disposed on the surface of the over-coating layer, the light emitting device comprising an anode and a cathode facing each other, and at least two blue stacks and a phosphorescent stack between the anode and the cathode, at least one of the blue stacks is the blue light emitting layer and includes an electron transport layer including a first material, the electron transport layer being in contact with the blue light emitting layer.

A light-emitting element which includes a plurality of light-emitting layers between a pair of electrodes and has low driving voltage and high emission efficiency is provided. A light-emitting element including first to third light-emitting layers between a cathode and an anode is provided. The first light-emitting layer includes a first phosphorescent material and a first electron-transport material; the second light-emitting layer includes a second phosphorescent material and a second electron-transport material; the third light-emitting layer includes a fluorescent material and a third electron-transport material; the first to third light-emitting elements are provided in contact with an electron-transport layer positioned on a cathode side; and a triplet excitation energy level of a material included in the electron-transport layer is lower than triplet excitation energy levels of the first electron-transport material and the second electron-transport material.

Novel organic compounds comprising a bicarbazole core are provided. In particular, the compounds has a 3,3′-bicarbazole core substituted at the 9-position with a triazine or pyrimidine. The compounds may be used in organic light emitting devices to provide devices having improved efficiency and improved lifetime.

Devices containing novel carbazole-containing compounds are provided. The novel compounds also contain electron donor groups, aryl linkers, and at least one nitrogen heterocycle. These novel organic compounds can exhibit delayed fluorescence in the devices.

A compound represented by the following formula (1), wherein X.sub.1 is O or S, and two or more of Y.sub.1, Y.sub.2 and Y.sub.3 are N, provided that the case where one or both of —Ar.sub.1-Ar.sub.2 and —Ar.sub.3-Ar.sub.4 is a p-terphenyl-3-yl group is excluded. ##STR00001##

An organic light emitting diode display panel, a manufacturing method thereof, and a display device are disclosed. The organic light emitting diode display panel includes: a base substrate; a light emitting layer on the base substrate, a spectral width at 10%-15% of a maximum spectral intensity of an emission spectrum of the light emitting layer is not less than 200 nm, and a yellow-green wave band of the emission spectrum includes at least one peak located between 550 nm-562 nm.

It is an object of the present invention to provide an image display apparatus capable of inhibiting or preventing the deterioration of a light conversion layer while high luminous efficiency and high color reproducibility are achieved. The present invention provides a light-emitting device including a pair of electrodes, an electroluminescent layer disposed between a first electrode and a second electrode, a light conversion layer including multiple pixels and converting light that is emitted from the electroluminescent layer and that has a blue emission spectrum into light having a different wavelength. The light conversion layer includes pixels of three primary colors of red (R), green (G), and blue (B) and contains a light-emitting nanocrystal having an emission spectrum in any of red (R), green (G), and blue (B) when light from the electroluminescent layer is incident on at least one of the three primary colors.

An organic light-emitting device includes a first electrode; a second electrode facing the first electrode; and an organic layer between the first electrode and the second electrode, the organic layer including an emission layer. The emission layer includes at least one heterocyclic compound of Formula 1. The heterocyclic compound may be a host or a delayed fluorescent dopant. The organic light-emitting device including the heterocyclic compound may have a low driving voltage, high efficiency, high luminance, and a long lifespan.

Disclosed are an organic light emitting display device and lighting apparatus for vehicles using the same. The organic light emitting display device includes a first layer including a first organic layer and a first emission layer on a first electrode, a second layer including a second emission layer and a second organic layer on the first layer, a second electrode on the second layer, and a third organic layer between the first layer and the second layer. A thickness of the first emission layer is equal to or greater than a thickness of each of the first organic layer and the second organic layer.