Abstract: A novel light-emitting device is provided. The light-emitting device includes a first electrode, a second electrode, and a light-emitting layer between the first electrode and the second electrode. The light-emitting layer includes an organometallic complex emitting phosphorescence at room temperature and a light-emitting material emitting fluorescence. The organometallic complex includes a ligand with at least one first substituent selected from a branched alkyl group having 3 to 12 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms in a ring, and a trialkylsilyl group having 3 to 12 carbon atoms. An absorption spectrum of the light-emitting material has the longest-wavelength edge at a first wavelength ?abs (nm), and a phosphorescence spectrum of the organometallic complex has the shortest-wavelength edge at a second wavelength ?p (nm). The first wavelength ?abs (nm) is longer than the second wavelength ?p (nm).

Abstract: It is an object of the present invention to provide a light emitting element, which is resistant to repetition of an oxidation reaction. It is another object of the invention to provide a light emitting element, which is resistant to repetition of a reduction reaction. An anthracene derivative is represented by a general formula (1). In the general formula (1), R1 represents hydrogen or an alkyl group having 1 to 4 carbon atoms, R2 represents any one of hydrogen, an alkyl group having 1 to 4 carbon atoms and an aryl group having 6 to 12 carbon atoms, R3 represents any one of hydrogen, an alkyl group having 1 to 4 carbon atoms, and an aryl group having 6 to 12 carbon atoms, Ph1 represents a phenyl group, and X1 represents an arylene group having 6 to 15 carbon atoms.

Abstract: A novel light-emitting device, a light-emitting device with high emission efficiency, a light-emitting device with a long lifetime, or a light-emitting device with low driving voltage is provided. An EL layer includes a first layer, a second layer, a third layer, a light-emitting layer, and a fourth layer in this order from the anode side. The first layer contains a first organic compound and a second organic compound. The fourth layer contains a seventh organic compound. The first organic compound exhibits an electron-accepting property with respect to the second organic compound. A HOMO level of the second organic compound is higher than or equal to ?5.7 eV and lower than or equal to ?5.4 eV. The fourth layer includes a region where the amount of seventh organic compound is large and a region where the amount of seventh organic compound is small in the thickness direction.

Abstract: A light-emitting device with high emission efficiency and low driving voltage is provided. A light-emitting apparatus, an electronic device, and a lighting device with low power consumption are provided. The following organic compound is provided: the organic compound has an arylamine structure; and when the organic compound is deposited to be a film, the ordinary refractive index of the deposited film with respect to light with a wavelength of 458 nm is greater than or equal to 1.50 and less than or equal to 1.75, the birefringence ?n of the deposited film with respect to light with a wavelength of 458 nm is greater than or equal to 0 and less than or equal to 0.008, or the alignment order parameter of the deposited film with respect to light with a wavelength corresponding to the longest wavelength where an absorption peak appears in the absorption spectrum is greater than or equal to ?0.07 and less than or equal to 0.00.

Abstract: A light-emitting device is provided. The light-emitting device includes an intermediate layer, a first light-emitting unit, and a second light-emitting unit. The intermediate layer includes a region interposed between the first light-emitting unit and the second light-emitting unit. The intermediate layer has a function of supplying an electron to one of the first light-emitting unit and the second light-emitting unit and supplying a hole to the other. The first light-emitting unit includes a first light-emitting layer, the first light-emitting layer includes a first light-emitting material, the second light-emitting unit includes a second light-emitting layer, the second light-emitting layer includes a second light-emitting material, the second light-emitting layer has a first distance from the first light-emitting layer, and the first distance is longer than or equal to 5 nm and shorter than or equal to 65 nm.

Abstract: A display device that has a function of emitting visible light and infrared light and a function of detecting light. The display device is a display device including a first light-emitting device, a second light-emitting device, and a light-receiving device, in a display portion. The first light-emitting device includes a first pixel electrode, a first optical adjustment layer, a first light-emitting layer, a second light-emitting layer, and a common electrode. The second light-emitting device includes a second pixel electrode, a second optical adjustment layer, the first light-emitting layer, the second light-emitting layer, and the common electrode. The light-receiving device includes a third pixel electrode, an active layer, and the common electrode. The active layer includes an organic compound. The first light-emitting device emits infrared light emitted by the first light-emitting layer. The second light-emitting device emits visible light emitted by the second light-emitting layer.

Abstract: One object of this invention is to provide a novel light-emitting device with low power consumption. The light-emitting device includes a first light-emitting element and a second light-emitting element. The first light-emitting element includes a first electrode, a second electrode, and a light-emitting layer. The second light-emitting element includes the first electrode, a third electrode, and the light-emitting layer. The second electrode comprises only a first conductive film, and the third electrode comprises a second conductive film and a third conductive film. The first electrode has a function of reflecting light. The second conductive film has functions of reflecting light and transmitting light. The first conductive film and the third conductive film each have a function of transmitting light.

Abstract: Provided is a composition for a light-emitting device, which enables manufacture of a highly productive light-emitting device while device characteristics and reliability of the light-emitting device are maintained. The composition for a light-emitting device is formed by mixing a plurality of organic compounds. A first organic compound having a diazine skeleton (preferably, a benzofurodiazine skeleton, a naphthofurodiazine skeleton, a phenanthrofurodiazine skeleton, a benzothienodiazine skeleton, a naphthothienodiazine skeleton, or a phenanthrothienodiazine skeleton) and a second organic compound that is an aromatic amine compound are mixed to form the composition for a light-emitting device.

Abstract: A display apparatus having a function of emitting visible light and infrared light and a light detection function is provided. The display apparatus includes a first light-emitting device, a second light-emitting device, and a light-receiving device in a display portion. The first light-emitting device emits both visible light and infrared light and the second light-emitting device emits visible light. The light-receiving device has a function of absorbing at least part of visible light and infrared light. The first light-emitting device includes a first pixel electrode, a first light-emitting layer, a second light-emitting layer, and a common electrode. The second light-emitting device includes a second pixel electrode, a third light-emitting layer, and the common electrode. The light-receiving device includes a third pixel electrode, an active layer, and the common electrode. The first light-emitting layer includes a light-emitting material emitting infrared light.

Abstract: A novel light-emitting device with a microcavity structure which can improve the emission efficiency compared to the conventional one is provided. In a light-emitting device with a microcavity structure that emits light in a near-infrared range, reflectance of one or both of a first electrode (reflective electrode) and a second electrode (semi-transmissive and semi-reflective electrode) with respect to light in a near-infrared range (e.g., light with a wavelength of 850 nm) is higher than the reflectance thereof with respect to light in a visible light range (greater than or equal to 400 nm and less than 750 nm).

Abstract: An object is to provide a novel composition for an EL device. Another object of one embodiment of the present invention is to provide a composition for an EL device capable of easily manufacturing an EL device with stable characteristics. Another object of one embodiment of the present invention is to provide a composition for an EL device capable of manufacturing an EL device with stable characteristics at low cost. The present inventors have studied a composition for an EL device in which different substances are mixed in advance and which does not cause change in characteristics of the EL device even when evaporation is repeated with use of the composition. As a result, a composition for an EL device in which a difference in the 5% weight loss temperature under a pressure lower than or equal to 0.1 Pa between contained substances is less than or equal to 50° C. is provided.

Abstract: Provided is a light-emitting element which includes a first electrode, a second electrode over the first electrode, and first and second light-emitting layers therebetween. The first light-emitting layer contains a first host material and a first light-emitting material, and the second light-emitting layer contains a second host material and a second light-emitting material. The first light-emitting material is a fluorescent material, and the second light-emitting material is a phosphorescent material. The level of the lowest triplet excited state (T1 level) of the first light-emitting material is higher than the T1 level of the first host material. A light-emitting device, an electronic device, and a lighting device including the light-emitting element are further provided.

Abstract: A light-emitting device with high outcoupling efficiency is provided. In the light-emitting device including a light-emitting layer between a pair of electrodes, a low refractive index layer containing an organic compound and an inorganic compound is provided between the light-emitting layer and an anode or between the light-emitting layer and a cathode, and the low refractive index layer has a refractive index of less than or equal to 1.80 at a wavelength of light extracted from the light-emitting layer.

Abstract: A reliable light-emitting element with low driving voltage is provided. The light-emitting element includes an electron-injection layer between a cathode and a light-emitting layer. The electron-injection layer is a mixed film of a transition metal and an organic compound having an unshared electron pair. An atom of the transition metal and the organic compound form SOMO.

Abstract: Providing a light-emitting element emitting light in a broad emission spectrum. A combination of a first organic compound and a second organic compound forms an exciplex. The first organic compound has a function of converting triplet-excitation energy into light emission. The lowest triplet excitation level of the second organic compound is higher than or equal to the lowest triplet excitation level of the first organic compound, and the lowest triplet excitation level of the first organic compound is higher than or equal to the lowest triplet excitation level of the exciplex. Light emission from a light-emitting layer includes light emission from the first organic compound and light emission from the exciplex.

Abstract: To provide a light-emitting device whose amount of light can be adjusted, or the like. The amount of light emitted from the light-emitting device can be adjusted by controlling the magnitude of the constant current pulse by a control signal. Specifically, the light-emitting device includes a constant current supply configured to be supplied with a control signal and a control pulse signal and configured to supply a constant current pulse; a control device configured to supply the control signal; a driver circuit configured to supply the control pulse signal; and a light-emitting panel configured to be supplied with the constant current pulse. The control signal is a signal for controlling the magnitude of the constant current pulse. The light-emitting panel includes a light-emitting element. The current density of the light-emitting element is greater than or equal to 10 mA/cm2 and less than or equal to 1000 mA/cm2.

Abstract: An anthracene derivative represented by a general formula (1) and an organic compound represented by a general formula (8) are provided. Further, by use of the anthracene derivative represented by the general formula (1), a light-emitting element with high emission efficiency can be obtained. Furthermore, by use of the anthracene derivative represented by the general formula (1), a light-emitting element that emits blue light with high color purity can be obtained.

Abstract: A light-emitting device with high emission efficiency and high reliability is provided. The light-emitting device includes a host material and a guest material in a light-emitting layer. The host material has a function of converting triplet excitation energy into light emission and the guest material emits fluorescence. The guest material has a molecular structure including a luminophore and protecting groups, and five or more protecting groups are included in one molecule of the guest materials. When the protecting groups are introduced into the molecule, triplet excitation energy transfer from the host material to the guest material by the Dexter mechanism is inhibited. As the protecting group, an alkyl group or a branched-chain alkyl group is used. A light-emitting device with improved emission efficiency can be obtained with the use of a material having a five-membered ring skeleton in the host material.

Abstract: A light-emitting device material with a low refractive index is provided. The light-emitting device material contains an organic compound which has a pyridine skeleton, a diazine skeleton, or a triazine skeleton and in which the proportion of carbon atoms forming a bond by sp3 hybrid orbitals is within a certain range. The light-emitting device material contains an organic compound including at least one six-membered heteroaromatic ring having 1 to 3 nitrogen atoms and a plurality of aromatic hydrocarbon rings each having 6 to 14 carbon atoms in a ring. At least two of the plurality of aromatic hydrocarbon rings are benzene rings. The organic compound has a plurality of hydrocarbon groups forming a bond by the sp3 hybrid orbitals. The ordinary refractive index of a layer containing the organic compound with respect to light with a wavelength in the range from 455 nm to 465 nm is 1.5 to 1.75.

Abstract: A light-emitting device with high emission efficiency is provided. The light-emitting device includes an anode, a cathode, and an EL layer positioned between the anode and the cathode. The EL layer includes a light-emitting layer and an electron-transport layer; the light-emitting layer includes a light-emitting material; the electron-transport layer includes an organic compound having an electron-transport property and a metal complex of an alkali metal; the ordinary refractive index of the organic compound having an electron-transport property in a peak wavelength of light emitted from the light-emitting material is greater than or equal to 1.50 and less than or equal to 1.75; and the ordinary refractive index of the metal complex of an alkali metal in the peak wavelength of the light emitted from the light-emitting material is greater than or equal to 1.45 and less than or equal to 1.70.