Abstract:
It is an object to provide a novel material having a bipolar property, a light emitting element provided with the novel material, and a display device that includes the light emitting element. It is an object to provide a pyrazine derivative represented by the following general formula (g-1).
Abstract:
The volume density or weight density of lithium ions that can be received and released in and from a positive electrode active material is increased to achieve high capacity and high energy density of a secondary battery. In a lithium manganese composite oxide, each particle includes a first region including a crystal with a layered rock-salt crystal structure and a second region including a crystal with a spinel crystal structure. The second region is in contact with the outside of the first region. The lithium manganese composite oxide has high structural stability and high capacity.
Abstract:
As a novel substance having a novel skeleton, provided is a novel phosphorescent organometallic iridium complex that can emit phosphorescence in a blue green to red wavelength region and has high emission efficiency. The phosphorescent organometallic iridium complex has a ligand having a pyridyl pyrimidine skeleton, i.e., the phosphorescent organometallic iridium complex has a ligand having a structure represented by the following general formula (G0). Note that in the formula, R1 and R4 to R6 separately represent hydrogen or an alkyl group having 1 to 6 carbon atoms; and R2 and R3 separately represent any of hydrogen, an alkyl group having 1 to 6 carbon atoms, a phenyl group that may have a substituent, and a pyridyl group that may have a substituent.
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:
A positive electrode active material that achieves high capacity and high energy density of a secondary battery is provided. The positive electrode active material is represented by Li2Mn1-XAXO3 and contains a metal element, Si, or P as A. The positive electrode active material has higher discharge capacity than Li2MnO3.
Abstract:
A light-emitting element including a phosphorescent organometallic complex is provided. The organometallic complex emits phosphorescence in the yellow green to orange wavelength range and has high emission efficiency and high reliability. Thus, the organometallic complex that exhibits phosphorescence is provided. The organometallic complex, in which nitrogen at the 3-position of a pyrimidine ring is coordinated to a metal, a carbazole skeleton is bonded to the 4-position of the pyrimidine ring, and the carbazole skeleton is bonded to the metal, is used as an emission center. The metal is preferably a Group 9 element or a Group 10 element, more preferably iridium.
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:
A novel organic compound that forms an exciplex emitting light with high efficiency is provided. An organic compound with a triarylamine skeleton in which the three aryl groups of the triarylamine skeleton are a p-biphenyl group, a fluoren-2-yl group, and a phenyl group to which a dibenzofuranyl group or a dibenzothiophenyl group is bonded. By the use of the organic compound and an organic compound with an electron-transport property, an exciplex that emits light with extremely high efficiency can be formed.
Abstract:
Provided is a novel organometallic complex which can be synthesized easily and emits phosphorescence, or a compound which emits red phosphorescence. The inventors focused on easy synthesis of an m-aminophenyl pyrazine derivative represented by the following general formula (G0), synthesized an organometallic complex having a structure in which the derivative is coordinated to a Group 9 or Group 10 metal ion, and further synthesized a useful substance which emits red phosphorescence.
Abstract:
Novel anthracene derivatives are provided. Further, a light-emitting element, a light-emitting device, and an electronic appliance each using the novel anthracene derivative are provided. Anthracene derivatives represented by general formulae (G11) and (G21) are provided. The anthracene derivatives represented by the general formulae (G11) and (G21) each emit blue light with high color purity and have a carrier-transporting property. Therefore, each of the anthracene derivatives represented by the general formulae (G11) and (G21) is suitable for use in a light-emitting element, a light-emitting device, and an electronic appliance.