Abstract: A light-emitting element with high emission efficiency. The light-emitting element includes a first organic compound, a second organic compound, and a guest material. The LUMO level of the first organic compound is lower than the LUMO level of the second organic compound. The HOMO level of the first organic compound is lower than the HOMO level of the second organic compound. The HOMO level of the guest material is higher than the HOMO level of the second organic compound. The energy difference between the LUMO level of the guest material and the HOMO level of the guest material is larger than the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound. The guest material has a function of converting triplet excitation energy into light emission. The first organic compound and the second organic compound form an exciplex.

Abstract: A novel organic compound is to be provided. In other words, a novel organic compound effective in improving element characteristics is to be provided. The organic compound is represented by General Formula (G1) shown below. In General Formula (G1) above, at least one or two of A1 to A4 represent nitrogen, and the others represent carbon. At least one or two of A5 to A8 represent nitrogen, and the others represent carbon. In addition, B1 and B2 each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, or a cyano group. In addition, Htuni1 and Htuni2 each independently represent a hole-transport skeleton.

Abstract: A novel organic compound is provided. A novel organic compound having a carrier-transport property is provided. A novel organic compound having a hole-transport property is provided. An organic compound having a low refractive index is provided. An organic compound having a low refractive index and a carrier-transport property is provided. An organic compound having a low refractive index and a hole-transport property is provided. An organic compound represented by the following general formula (G1) is provided.

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: A light-emitting element having a long lifetime is provided. A light-emitting element exhibiting high emission efficiency in a high luminance region is provided. A light-emitting element includes a light-emitting layer between a pair of electrodes. The light-emitting layer contains a first organic compound, a second organic compound, and a phosphorescent compound. The first organic compound is represented by a general formula (GO). The molecular weight of the first organic compound is greater than or equal to 500 and less than or equal to 2000. The second organic compound is a compound having an electron-transport property. In the general formula (GO), Ar1 and Ar2 each independently represent a fluorenyl group, a spirofluorenyl group, or a biphenyl group, and Ar3 represents a substituent including a carbazole skeleton.

Abstract: A novel light-emitting device that is highly convenient, useful, or reliable is provided. The light-emitting device includes a first electrode, a second electrode, and a first layer. The first layer is positioned between the first electrode and the second electrode. The first layer includes a light-emitting material, a first organic compound, and a first material. The light-emitting material has a function of emitting fluorescent light. The absorption spectrum of the light-emitting material has the longest-wavelength edge at a first wavelength. The first organic compound has a function of converting triplet excitation energy into light emission. The spectrum of the emitted light has the shortest-wavelength edge at a second wavelength. The second wavelength is positioned at a wavelength shorter than the first wavelength. The first organic compound includes a first substituent R1. The first substituent R1 is any of an alkyl group, a substituted or unsubstituted cycloalkyl group, and a trialkylsilyl group.

Abstract: A light-emitting device with high heat resistance in a manufacturing process is to be provided.

Abstract: A lightweight flexible light-emitting device which is able to possess a curved display portion and display a full color image with high resolution and the manufacturing process thereof are disclosed. The light-emitting device comprises: a plastic substrate; an insulating layer with an adhesive interposed therebetween; a thin film transistor over the insulating layer; a protective insulating film over the thin film transistor; a color filter over the protective insulating film; an interlayer insulating film over the color filter; and a white-emissive light-emitting element formed over the interlayer insulating film and being electrically connected to the thin film transistor.

Abstract: A novel organic compound is provided. Alternatively, an organic compound that exhibits light emission with favorable chromaticity is provided. Alternatively, an organic compound that exhibits blue light emission with favorable chromaticity is provided. Alternatively, an organic compound with favorable emission efficiency is provided. Alternatively, an organic compound having a high carrier-transport property is provided. Alternatively, an organic compound with favorable reliability is provided. An organic compound including at least one amino group in which any one of a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothiophenyl group, and a substituted or unsubstituted carbazolyl group is boneded to any one of a substituted or unsubstituted naphthobisbenzofuran skeleton, a substituted or unsubstituted naphthobisbenzothiophene skeleton, and a substituted or unsubstituted naphthobenzofuranobenzothiophene skeleton is provided.

Abstract: An object is to provide a highly reliable display unit having a function of sensing light. The display unit includes a light-receiving device and a light-emitting device. The light-receiving device includes an active layer between a pair of electrodes. The light-emitting device includes a hole-injection layer, a light-emitting layer, and an electron-transport layer between a pair of electrodes. The light-receiving device and the light-emitting device share one of the electrodes, and may further share another common layer between the pair of electrodes. The hole-injection layer is in contact with an anode and contains a first compound and a second compound. The electron-transport property of the electron-transport layer is low; hence, the light-emitting layer is less likely to have excess electrons. Here, the first compound is the material having a property of accepting electrons from the second compound.

Abstract: A light-emitting device with high heat resistance in a manufacturing process is to be provided.

Abstract: A light-emitting apparatus can be provided at low cost. The light-emitting apparatus includes a plurality of partitions formed over an insulating surface and extending in a first direction, a plurality of pixel electrodes each having an island shape formed over the insulating surface, an EL layer formed over the pixel electrodes, and a second electrode formed over the EL layer. The partition has an insulating property, the pixel electrodes that are aligned in the first direction are positioned column by column between adjacent partitions in the plurality of partitions, and the EL layer is in contact with the insulating surface between the pixel electrodes adjacent to each other in the first direction in the pixel electrodes aligned in the first direction.

Abstract: Intake efficiency in an intake system is improved. An intake system takes air through an air inlet duct extending from an air cleaner case, and includes a vortex generator that causes the flow of the intake air inside the air inlet duct to rotate around an axis of the air inlet duct.

Abstract: A light-emitting element having high emission efficiency is provided. The light-emitting element includes a first organic compound, a second organic compound, and a third organic compound. The first organic compound has a function of converting triplet excitation energy into light emission. The second organic compound is preferably a TADF material. The third organic compound is a fluorescent compound. Light emitted from the light-emitting element is obtained from the third organic compound. Triplet excitation energy in a light-emitting layer is transferred to the third organic compound by reverse intersystem crossing caused by the second organic compound or through the first organic compound.

Abstract: A light-emitting element with high emission efficiency and high reliability is provided. The light-emitting element 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 molecular structure of the guest material is a structure including a luminophore and protecting groups, and five or more protecting groups are included in one molecule of the guest material. The introduction of the protecting groups into the molecule inhibits energy transfer of triplet excitation energy by the Dexter mechanism from the host material to the guest material. As the protecting group, an alkyl group or a branched-chain alkyl group is used.

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: A novel mixed material with improved resistance is provided. The mixed material includes a first heteroaromatic compound and a second heteroaromatic compound, and the first heteroaromatic compound is represented by any one of General Formulae (G1) to (G6). The second heteroaromatic compound is not represented by the same general formula as that of the first heteroaromatic compound.

Abstract: A novel light-emitting device is provided. Alternatively, a light-emitting device having a long driving lifetime at high temperature 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 first layer, a second layer, a third layer, and a light-emitting layer in this order from the anode side. The first layer includes a first organic compound and a second organic compound. The second layer includes a third organic compound. The third layer includes a fourth organic compound. The light-emitting layer includes a fifth organic compound and an emission center substance. The first organic compound exhibits an electron-accepting property with respect to the second organic compound. A difference between HOMO levels of the fourth organic compound and the fifth organic compound is less than or equal to 0.24 eV.

Abstract: A novel ionic liquid is provided. A highly safe secondary battery with high charge and discharge capacity is provided. The ionic liquid includes a cation represented by General Formula (G1) and an anion represented by Structural Formula (200). In the formula, X1 to X3 each independently represent any one of fluorine, chlorine, bromine, and iodine. One of X1 to X3 may be hydrogen. In addition, n and m each independently represent 0 to 5. Furthermore, a secondary battery including the above-described ionic liquid is provided.

Abstract: A novel light-emitting device that is highly convenient, useful, or reliable is provided. The light-emitting device includes an anode over a cathode with an EL layer sandwiched therebetween. The EL layer includes at least a light-emitting layer and an oxidation-resistant layer over the light-emitting layer. The EL layer has a side surface. The light-emitting device includes a block layer in contact with a top surface and the side surface of the EL layer. The cathode is in contact with the side surface of the EL layer with the block layer therebetween. The block layer includes a heterocyclic compound. In the light-emitting device with the above structure, the oxidation-resistant layer may include any one or a plurality of oxides of metals belonging to Group 4 to Group 8 of the periodic table and an organic compound having an electron-withdrawing group.