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 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 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: To provide a light-emitting element with high emission efficiency and low driving voltage. The light-emitting element includes a guest material and a host material. A LUMO level of the guest material is lower than a LUMO level of the host material. An energy difference between the LUMO level and a HOMO level of the guest material is larger than an energy difference between the LUMO level and a HOMO level of the host material. The guest material has a function of converting triplet excitation energy into light emission. An energy difference between the LUMO level of the guest material and the HOMO level of the host material is larger than or equal to energy of light emission of the guest material.

Abstract: A light-emitting apparatus with low power consumption is provided. A light-emitting apparatus including a first light-emitting device and a first color conversion layer. The first light-emitting device includes an anode, a cathode, and an EL layer positioned between the anode and the cathode. The EL layer includes a layer including a material with a refractive index lower than or equal to 1.75 at 467 nm. The first color conversion layer includes a first substance capable of emission by absorbing light. Light emitted from the first light-emitting device enters the first color conversion layer.

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 light-emitting device with low power consumption is provided. The light-emitting apparatus including a first light-emitting device and a first color conversion layer. The first light-emitting device includes an anode, a cathode, and an EL layer between the anode and the cathode. The EL layer includes a layer including a material with an ordinary refractive index higher than or equal to 1.50 and lower than 1.75 with respect to light with a wavelength longer than or equal to 455 nm and shorter than or equal to 465 nm. The first color conversion layer includes a first substance that absorbs light and emits light. An ordinary refractive index of the first color conversion layer with respect to light with a wavelength longer than or equal to 455 nm and shorter than or equal to 465 nm is higher than or equal to 1.40 and lower than or equal to 2.10. The first color conversion layer is on an optical path of the light emitted from the first light-emitting device to an outside of the light-emitting apparatus.

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.

Abstract: Provided is a light-emitting device with high emission efficiency. Provided is a light-emitting device including an anode, a cathode, and an EL layer positioned therebetween; the EL layer includes a light-emitting layer, a first layer, and a second layer; the first layer is positioned between the anode and the light-emitting layer; the first layer is in contact with the second layer; the second layer contains a monoamine compound having an arylamine structure; a first group, a second group, and a third group are bonded to a nitrogen atom included in the amine in the monoamine compound; the first group is a group including a carbazole structure; the second group is a group including a dibenzofuran structure or a dibenzothiophene structure; the third group includes an aromatic hydrocarbon structure having 6 to 18 carbon atoms or a heteroaromatic hydrocarbon structure having 4 to 26 carbon atoms; and a refractive index of the first layer is lower than a refractive index of the light-emitting layer.

Abstract: An electronic device or a light-emitting device with high design flexibility and favorable reliability is provided by the following steps. A light-emitting layer containing a first organic compound and a second organic compound is formed over a substrate provided with a first electrode, the substrate is held under lighting of a light source whose shortest-wavelength emission edge among emission edges in an emission spectrum is positioned at a wavelength shorter than a wavelength of the longest-wavelength absorption edge among absorption edges in an absorption spectrum of the first organic compound and at a wavelength longer than a wavelength of the longest-wavelength absorption edge among absorption edges in an absorption spectrum of the second organic compound, a sacrificial layer is formed over the light-emitting layer, at least the light-emitting layer is processed into an island shape by a photolithography method, and a second electrode is formed over the light-emitting layer.

Abstract: A novel light-emitting device that is highly convenient, useful, or reliable is provided. The light-emitting device includes a first reflective film, first to fourth layers, and a first electrode. The first electrode overlaps with the first reflective film. The fourth layer is positioned between the first electrode and the first reflective film, and contains a first light-emitting material, which has an emission spectrum having a peak at a first wavelength. The third layer is positioned between the fourth layer and the first reflective film, and contains an organic compound having an ordinary refractive index of 1.45 to 1.75. The second layer is positioned between the third layer and the first reflective film, has a property of transmitting light with the first wavelength, includes a second electrode, and contains an element with an atomic number of 21 to 83 at 5 atomic % or higher.

Abstract: To provide a light-emitting element with high emission efficiency and low driving voltage. The light-emitting element includes a guest material and a host material. A LUMO level of the host material is higher than a LUMO level of the host material, and a HOMO level of the guest material is lower than a HOMO level of the host material. The guest material has a function of converting triplet excitation energy into light emission. The difference between a singlet excitation energy level and a triplet excitation energy level of the host material is greater than 0 eV and less than or equal to 0.2 eV. The energy difference between the LUMO level and the HOMO level of the host material is larger than or equal to light emission energy of the guest material.

Abstract: A novel organic compound is provided. The organic compound is represented by General Formula (G1).

Abstract: An electron-injection organic compound capable of providing a high-performance semiconductor device, and a light-emitting device including the organic compound are provided. An organic compound represented by General Formula (G1) and a light-emitting device including the organic compound are provided. Note that in General Formula (G1), R1 to R8 each independently represent any of hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 6 to 30 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, a substituted or unsubstituted heteroaromatic hydrocarbon group having 2 to 30 carbon atoms, and a group represented by Structural Formula (R-1). Note that at least two of R1 to R8 each represent a group other than hydrogen, and one to four of R1 to R8 each represent the group represented by Structural Formula (R-1).

Abstract: An electron-injection organic compound with low solubility in water is provided. An organic compound represented by General Formula (G1) is provided. In the organic compound, Ar represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms forming a ring or a substituted or unsubstituted heteroaromatic hydrocarbon group having 2 to 30 carbon atoms forming a ring, each of R1 and R2 independently represents hydrogen (including deuterium), an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 13 carbon atoms forming a ring, n represents an integer greater than or equal to 1 and less than or equal to 6, and L is the group represented by General Formula (L-1).

Abstract: A light-emitting apparatus with low power consumption is provided. A light-emitting apparatus including a first light-emitting device and a first color conversion layer. The first light-emitting device includes an anode, a cathode, and an EL layer positioned between the anode and the cathode. The EL layer includes a layer including a material with a refractive index lower than or equal to 1.75 at 467 nm. The first color conversion layer includes a first substance capable of emission by absorbing light. Light emitted from the first light-emitting device enters the first color conversion layer.

Abstract: An electronic device or a light-emitting device with high design flexibility and favorable reliability is provided by the following steps. A light-emitting layer containing organic compounds is formed over a substrate provided with a first electrode, the substrate is held in lighting of a light source whose shortest-wavelength peak among spectrum peaks is positioned at a wavelength longer than a longest-wavelength absorption edge among absorption edges in absorption spectra of the organic compounds, a sacrificial layer is formed over the light-emitting layer, at least the light-emitting layer is processed into an island shape by a lithography method, and a second electrode is formed over the light-emitting layer.

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, a unit, and a first layer. The unit is positioned between the first electrode and the second electrode and includes a second layer, a third layer, and a fourth layer. The second layer is positioned between the third layer and the fourth layer and contains a light-emitting material. The third layer is positioned between the second layer and the second electrode, is in contact with the second layer, and contains a first material, and an organometallic complex of an alkali metal or an organometallic complex of an alkaline earth metal. The fourth layer is positioned between the first electrode and the second layer and contains a second material. The first layer is positioned between the first electrode and the unit and contains a second material and a material having an electron acceptor property. The second material has a first refractive index.

Abstract: A novel optical functional device that is highly convenient, useful, or reliable is provided. A light-emitting device includes a first electrode, a second electrode, and an EL layer. The first electrode has a first transmittance; the second electrode overlaps with the first electrode. The second electrode has a second transmittance higher than the first transmittance. The EL layer is interposed between the first electrode and the second electrode and includes a first region, a second region, and a third region. The first region is interposed between the second region and the third region. The second region is interposed between the first electrode and the first region and has a first refractive index. The third region is interposed between the first region and the second electrode and has a second refractive index. The second refractive index is lower than the first refractive index. The EL layer includes a first unit, a second unit, and an intermediate layer.

Abstract: A novel organometallic complex with high heat resistance is provided. The organometallic complex includes a structure represented by General Formula (G1) below, in which iridium and a ligand are included, the ligand includes a pyrazine skeleton, iridium is bonded to nitrogen at the 1-position of the pyrazine skeleton, an aryl group including a cyano group as a substituent is bonded at the 5-position of the pyrazine skeleton, and each of the 3-position and the 6-position of the pyrazine skeleton is independently bonded to any one of hydrogen, an alkyl group, and an alkoxy group. (In the formula, A represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 25 carbon atoms. In addition, Ar represents an aryl group having 6 to 25 carbon atoms and at least one cyano group as a substituent. Each of R1 and R2 independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms.