Abstract: A novel substance with which an increase in life and emission efficiency of a light-emitting element can be achieved is provided. A carbazole compound having a structure represented by General Formula (G1) is provided. Note that a substituent which makes the HOMO level and the LUMO level of a compound in which a bond of the substituent is substituted with hydrogen deep and shallow, respectively is used as each of substituents in General Formula (G1) (R1, R2, Ar3, and ?3). Further, a substituent which makes the band gap (Bg) and the T1 level of a compound in which a bond of the substituent is substituted with hydrogen wide and high is used as each of the substituents in General Formula (G1) (R1, R2, Ar3, and ?3).

Abstract: Provided is a novel substance that can emit phosphorescence. Alternatively, provided is a novel substance with high emission efficiency. An organometallic complex in which a 4-arylpyrimidine derivative is a ligand and iridium is a central metal is provided. Specifically, an organometallic complex having a structure represented by a general formula (G1) is provided. In the general formula (G1), R1 represents a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms or a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, R2 represents any of hydrogen, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, and a substituted or unsubstituted phenyl group, R3 represents hydrogen or a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, and Ar1 represents a substituted or unsubstituted arylene group having 6 to 10 carbon atoms.

Abstract: To provide a novel organometallic complex, and light emitting elements, light emitting devices, and electronic devices which include the organometallic complex. In addition, to provide a composition in which the organometallic complex is dissolved and to provide a method for manufacturing light emitting elements using the composition. An organometallic complex has high solubility in a solvent. In the organometallic complex, the ligand including a pyrazine skeleton is bound to an atom belonging to Group 9 (Co, Rh, or Ir) or an atom belonging to Group 10 (Ni, Pd, or Pt). In addition, the light emission efficiency is high. Therefore, the organometallic complex is preferably used for manufacturing a light emitting element.

Abstract: A substance having a hole-transport property and a wide band gap is provided. A fluorene compound represented by a general formula (G1) is provided. In the general formula (G1), ?1 and ?2 separately represent a substituted or unsubstituted arylene group having 6 to 13 carbon atoms; Ar1 represents a substituted or unsubstituted aryl group having 6 to 18 carbon atoms, a substituted or unsubstituted 4-dibenzothiophenyl group, or a substituted or unsubstituted 4-dibenzofuranyl group; n and k separately represent 0 or 1; Q1 represents sulfur or oxygen; and R1 to R15 separately represent hydrogen, an alkyl group having 1 to 12 carbon atoms, or an aryl group having 6 to 14 carbon atoms.

Abstract: Provided is a light-emitting element with high external quantum efficiency, or a light-emitting element with a long lifetime. The light-emitting element includes, between a pair of electrodes, a light-emitting layer including a guest material and a host material, in which an emission spectrum of the host material overlaps with an absorption spectrum of the guest material, and phosphorescence is emitted by conversion of an excitation energy of the host material into an excitation energy of the guest material. By using the overlap between the emission spectrum of the host material and the absorption spectrum of the guest material, the energy smoothly transfers from the host material to the guest material, so that the energy transfer efficiency of the light-emitting element is high. Accordingly, a light-emitting element with high external quantum efficiency can be achieved.

Abstract: In a sealing method of a top-emission organic light emitting element, in the case of using a method of filling with a sealing agent between a substrate mounted with pixels and an opposed substrate, the organic light-emitting element is degraded by ultraviolet rays when irradiation of the ultraviolet rays is performed toward the pixels in order to achieve ultraviolet curing of the sealing agent filling on the pixels. It is an object of the present invention to propose a method for avoiding this phenomenon to provide an organic light-emitting device with superior stability. In order for a sealing agent 13 filling on a pixel portion 14 to have a larger absorbance to ultraviolet rays, an ultraviolet-absorbent material is dispersed in a sealing agent to make an adjustment so that the absorbance of ultraviolet absorption wavelength of 400 nm or less becomes 1 or more.

Abstract: A light-emitting element having extremely high efficiency of approximately 25% is provided. The light-emitting element includes a light-emitting layer which contains a phosphorescent guest, an n-type host, and a p-type host, where the light-emitting layer is interposed between an n-type layer including the n-type host and a p-type layer including the p-type host, and where the n-type host and the p-type host are able to form an exciplex in the light-emitting layer. The light-emitting element exhibits an extremely high emission efficiency (power efficiency of 74.3 lm/W, external quantum efficiency of 24.5%, energy efficiency of 19.3%) at a low driving voltage (2.6 V) at which luminance of 1200 cd/m2 is attainable.

Abstract: In a light emitting element using an organic metal complex which can convert an excited triplet state into a light emission, a red color light emitting element exhibiting a high light emission efficiency and an excellent color purity is provided. A material used in a hole transporting layer and a host contained in a light emitting layer and an electron transporting layer has a triplet excitation energy larger than a triplet excitation energy of the organic metal complex which is a light emitting substance to enable a current efficiency and an external quantum efficiency of the light emitting element to be improved. It is possible to obtain a current efficiency of 2.0 cd/A or more and an external quantum efficiency of 5% or more. The color purity is excellent. The CIE chromaticity coordinate is X?0.7 and Y?0.3 to make it possible to exceed an NTSC standard.

Abstract: Provided is a novel substance that can emit phosphorescence. Alternatively, provided is a novel substance with high emission efficiency. An organometallic complex in which a 4-arylpyrimidine derivative is a ligand and iridium is a central metal is provided. Specifically, an organometallic complex having a structure represented by a general formula (G1) is provided. In the general formula (G1), R1 represents a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms or a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, R2 represents any of hydrogen, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, and a substituted or unsubstituted phenyl group, R3 represents hydrogen or a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, and Ar1 represents a substituted or unsubstituted arylene group having 6 to 10 carbon atoms.

Abstract: A light-emitting element disclosed in the present invention includes a light-emitting layer and a first layer between a first electrode and a second electrode, in which the first layer is provided between the light-emitting layer and the first electrode. The present invention is characterized by the device structure in which the first layer comprising a hole-transporting material is doped with a hole-blocking material or an organic compound having a large dipole moment. This structure allows the formation of a high performance light-emitting element with high luminous efficiency and long lifetime. The device structure of the present invention facilitates the control of the rate of the carrier transport, and thus, leads to the formation of a light-emitting element with a well-controlled carrier balance, which contributes to the excellent characteristics of the light-emitting element of the present invention.

Abstract: Provided is a light-emitting element which has an anode, a light-emitting layer over the anode, an electron-transport layer over and in contact with the light-emitting layer, an electron-injection layer over and in contact with the electron-transport layer, and a cathode over and in contact with the electron-injection layer. The light-emitting layer has an electron-transport property, and the electron-transport layer includes an anthracene derivative. The light-emitting layer further includes a phosphorescent substance. This device structure allows the formation of a highly efficient blue-emissive light-emitting element even though the phosphorescent substance has higher triplet energy than the anthracene derivative which directly contacts with the light-emitting layer.

Abstract: It is an object of the present invention to provide an organometallic complex which can increase recombination efficiency of electrons and holes. One aspect of the present invention is an organometallic complex having a structure represented by a general formula (1), wherein each of R1 and R2 is any of a halogen group, a —CF3 group, a cyano group, and an alkoxycarbonyl group, each of R3 and R4 is any of hydrogen and an alkyl group having 1 to 4 carbon atoms, and M is an element that belongs to Group 9 or 10 of the periodic table.

Abstract: A light-emitting element having extremely high efficiency of approximately 25% is provided. The light-emitting element includes a light-emitting layer which contains a phosphorescent guest, an n-type host, and a p-type host, where the light-emitting layer is interposed between an n-type layer including the n-type host and a p-type layer including the p-type host, and where the n-type host and the p-type host are able to form an exciplex in the light-emitting layer. The light-emitting element exhibits an extremely high emission efficiency (power efficiency of 74.3 lm/W, external quantum efficiency of 24.5%, energy efficiency of 19.3%) at a low driving voltage (2.6 V) at which luminance of 1200 cd/m2 is attainable.

Abstract: It is an object to provide a composition in which an anthracene derivative is dissolved and a technique in which a thin film that has a favorable film quality is formed by a wet process using the composition. In addition, it is another object to manufacture a highly reliable light-emitting element using the composition at low cost with high productivity. A composition having a solvent and an anthracene derivative having one anthracene structure and one carbazolyl group which is bonded to the anthracene structure directly or through a phenyl group is formed. A thin film with a favorable film quality can be formed by a wet process using the composition. Accordingly, a highly reliable light-emitting element can be manufactured using such a thin film.

Abstract: A light-emitting element whose lifetime is improved. In addition, a light-emitting device, a lighting device, and an electronic appliance in which the light-emitting element is used. A light-emitting element including, between an anode and a cathode, a hole-transport layer and a layer containing a light-emitting substance provided to be in contact with a cathode side surface of the hole-transport layer, in which the hole-transport layer includes a first organic compound and an anti-reduction substance, and in which the layer containing a light-emitting substance includes a second organic compound and a light-emitting substance and has at least an electron-transport property is provided. In addition, a light-emitting device including the light-emitting element, or a lighting device or an electronic appliance including the light-emitting device is provided.

Abstract: To provide a light-emitting element with high emission efficiency or long lifetime, in which the use amount of a phosphorescent compound is small. To provide a light-emitting element including a light-emitting layer between a pair of electrodes, wherein the light-emitting layer includes a phosphorescent compound, a first organic compound, and a second organic compound, and the combination of the first organic compound and the second organic compound forms an exciplex. The light-emitting element transfers energy by utilizing the overlap between the emission spectrum of the exciplex and the absorption spectrum of the phosphorescent compound and thus has high energy transfer efficiency, even when the concentration of the phosphorescent compound is low.

Abstract: An object is to provide a novel quinoxaline derivative, a light-emitting element with low driving voltage, and a light-emitting element which consumes low power. Another object is to provide a light-emitting device and an electronic appliance which consume low power by using the above light-emitting element. A quinoxaline derivative represented by a general formula (G11) is provided, in which at least one of carbon at a 2-position and carbon at a 3-position of quinoxaline, and carbon at a 2-position of a 1H-benzimidazole ring are bonded to each other via an arylene group.

Abstract: In a sealing method of a top-emission organic light emitting element, in the case of using a method of filling with a sealing agent between a substrate mounted with pixels and an opposed substrate, the organic light-emitting element is degraded by ultraviolet rays when irradiation of the ultraviolet rays is performed toward the pixels in order to achieve ultraviolet curing of the sealing agent filling on the pixels. It is an object of the present invention to propose a method for avoiding this phenomenon to provide an organic light-emitting device with superior stability. In order for a sealing agent 13 filling on a pixel portion 14 to have a larger absorbance to ultraviolet rays, an ultraviolet-absorbent material is dispersed in a sealing agent to make an adjustment so that the absorbance of ultraviolet absorption wavelength of 400 nm or less becomes 1 or more.

Abstract: Disclosed is a light-emitting element having high emission efficiency, capable of driving at low voltage, and showing a long lifetime. The light-emitting element contains a compound between a pair of electrodes, and the compound is configured to give a first peak of m/z around 202 and a second peak of m/z around 227 in a mass spectrum. The first and second peaks are product ions of the compound and possess compositions of C16H9 and C17H10N, respectively, which are derived from a dibenzo[f,h]quinoline unit.

Abstract: An object is to provide an organometallic complex whose phosphorescence characteristics can be adjusted by varying the structure of a ligand. Alternatively, an object is to provide an organometallic complex capable of emitting yellow phosphorescence with high luminance. Alternatively, an object is to provide a light-emitting device with high added value. An organometallic complex which has a structure represented by a general formula (G1) below and at least one substituent group represented by a general formula (G2) below as a phenyl group and is formed in such a way that a phenylpyrazine derivative represented by a general formula (G0) below is ortho-metalated by an ion of a Group 9 metal or of a Group 10 metal is provided. Alternatively, a light-emitting element and a light-emitting device formed including the organometallic complex are provided.