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.

Emission efficiency of a light-emitting element is improved. The light-emitting element has a pair of electrodes and an EL layer between the pair of electrodes. The EL layer includes a first light-emitting layer and a second light-emitting layer. The first light-emitting layer includes a fluorescent material and a host material. The second light-emitting layer includes a phosphorescent material, a first organic compound, and a second organic compound. An emission spectrum of the second light-emitting layer has a peak in a yellow wavelength region. The first organic compound and the second organic compound form an exciplex.

A light emitting element, includes a first light emitting layer and a second light emitting layer sequentially stacked; and an intermediate layer between the first light emitting layer and the second light emitting layer, and being in direct contact with the first light emitting layer on one side and in direct contact with the second light emitting layer on another side. Each of the intermediate layer, the first light emitting layer, and the second light emitting layer includes a same host material. The intermediate layer is a non-light emitting layer, and is an undoped layer absent of a dopant for emitting light. The light emitting element is configured to emit a composite light including the first light of the first wavelength range and the second light of the second wavelength range. The first wavelength range includes wavelength longer than the second wavelength range.

A light-emitting device with high emission efficiency is provided. The light-emitting device includes a fluorescent substance and a phosphorescent substance or a thermally activated delayed fluorescent material; the fluorescent substance includes a luminophore and five or more protecting groups; the luminophore is a condensed aromatic ring or a condensed heteroaromatic ring; the five or more protecting groups each have any one of an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, and a trialkylsilyl group having 3 to 12 carbon atoms; the lowest singlet excitation energy level of the fluorescent substance is higher than the lowest triplet excitation energy level of the phosphorescent substance or the thermally activated delayed fluorescent material; and light emission can be obtained from both the phosphorescent substance and the phosphorescent substance or the thermally activated delayed fluorescent material.

An organic light-emitting device including a first electrode, a second electrode facing the first electrode, and an emission layer disposed between the first electrode and the second electrode, wherein the emission layer includes a predetermined host and a thermally activated delayed fluorescence emitter.

Disclosed is an organic light-emitting diode and an organic light-emitting device including the organic light-emitting diode. The organic light-emitting diode includes a cathode electrode; an anode electrode; a first emitting material layer including a first host and a first delayed fluorescent material, which is between the cathode electrode and the anode electrode; and a second emitting material layer having a second delayed fluorescent material and a first fluorescent or phosphorescent material, between the cathode electrode and the anode electrode. The organic light-emitting diode has enhanced luminous efficiency and color continuity.

A display device includes: a substrate; a first insulating layer disposed on the substrate and that includes an inorganic insulating material; an oxide semiconductor layer disposed on the first insulating layer; a second insulating layer disposed on the oxide semiconductor layer and that includes an inorganic insulating material; and a third insulating layer disposed on a gate electrode disposed on the second insulating layer and that includes an inorganic insulating material. The oxide semiconductor layer includes a first conductive region, a second conductive region, and a channel region located between the first conductive region and the second conductive region, and a value in the channel region of the oxide semiconductor layer of HC according to equation (1) is less than 30%.

An organic light emitting diode includes: a first electrode layer; a second electrode layer on the first electrode layer and facing the first electrode layer; a first light emitting layer between the first electrode layer and the second electrode layer and comprising a phosphorescent material; a first hole control layer between the first electrode layer and the first light emitting layer; a second light emitting layer between the first light emitting layer and the second electrode layer and comprising a fluorescent material; and a charge generating layer between the first light emitting layer and the second light emitting layer, the first hole control layer having a thickness equal to or greater than 100 angstroms and equal to or smaller than 900 angstroms.

Provided are a light-emitting device 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 and at least one of an emission auxiliary layer and a buffer layer, the emission layer includes a host and a dopant, the dopant includes a first emissive compound and a second emissive compound, and the at least one of the emission auxiliary layer and the buffer layer includes a third emissive compound.

It is an object to provide a flexible light-emitting device with long lifetime in a simple way and to provide an inexpensive electronic device with long lifetime using the flexible light-emitting device. A flexible light-emitting device is provided, which includes a substrate having flexibility and a light-transmitting property with respect to visible light; a first adhesive layer over the substrate; an insulating film containing nitrogen and silicon over the first adhesive layer; a light-emitting element including a first electrode, a second electrode facing the first electrode, and an EL layer between the first electrode and the second electrode; a second adhesive layer over the second electrode; and a metal substrate over the second adhesive layer, wherein the thickness of the metal substrate is 10 μm to 200 μm inclusive. Further, an electronic device using the flexible light-emitting device is provided.