Abstract: A positive electrode active material with high charge and discharge capacity is provided. A positive electrode active material with high charge and discharge voltage is provided. A power storage device that hardly deteriorates is provided. A highly safe power storage device is provided. A novel power storage device is provided. A positive electrode active material containing lithium, a plurality of transition metals, oxygen, and an impurity element. The positive electrode active material includes a first region including a surface portion and a second region provided inward from the first region, and the concentration of a transition metal is higher in the first region than in the second region. An impurity region is included between the first region and the second region.

Abstract: A novel light-emitting device is provided. A light-emitting device with high emission efficiency is provided. A light-emitting device with a long lifetime is provided. A light-emitting device with low driving voltage is provided. The light-emitting device includes an anode, a cathode, and an EL layer between the anode and the cathode. The EL layer includes a hole-injection layer, a light-emitting layer, and an electron-transport layer. The hole-injection layer is positioned between the anode and the light-emitting layer. The electron-transport layer is positioned between the light-emitting layer and the cathode. The hole-injection layer contains a first substance and a second substance. The first substance is an organic compound which has a hole-transport property and a HOMO level higher than or equal to ?5.7 eV and lower than or equal to ?5.4 eV. The second substance exhibits an electron-accepting property with respect to the first substance.

Abstract: A property prediction system for a semiconductor element is provided. The property prediction system includes a memory unit, an input unit, a processing unit, and an arithmetic unit. The processing unit has a function of creating a learning data set from first data stored in the memory unit, a function of creating prediction data from second data supplied from the input unit, a function of converting qualitative data (a material name or a compositional formula) into quantitative data (the properties of an element and a composition), and a function of performing extraction or removal on the first data and the second data. The first data includes step lists of first to m-th semiconductor elements (m is an integer of 2 or more) and the properties of the first to m-th semiconductor elements. The second data includes a step list of an (m+1)-th semiconductor element.

Abstract: A novel light-emitting device is provided. A light-emitting device with high emission efficiency is provided. A light-emitting device with along lifetime is provided. A light-emitting device with low driving voltage is provided. The light-emitting device includes an anode, a cathode, and an EL layer between the anode and the cathode. The EL layer includes a hole-injection layer, a light-emitting layer, and an electron-transport layer. The hole-injection layer is positioned between the anode and the light-emitting layer. The electron-transport layer is positioned between the light-emitting layer and the cathode. The hole-injection layer contains a first substance and a second substance. The first substance is an organic compound which has a hole-transport property and a HOMO level higher than or equal to ?5.7 eV and lower than or equal to ?5.4 eV. The second substance exhibits an electron-accepting property with respect to the first substance.

Abstract: Provided is a positive electrode for a secondary battery, which has a small change in a crystal structure due to charging and discharging and has excellent cycle performance. The positive electrode for a secondary battery includes n positive electrode active material layers (n is an integer greater than or equal to 2), n?1 separation layer(s), and a positive electrode current collector layer. The positive electrode active material layers and the separation layer(s) are alternately stacked. The positive electrode active material layer contains lithium, cobalt, and oxygen. The separation layer contains a titanium compound. Titanium oxide and titanium nitride are preferable as the titanium compound, and titanium oxide is particularly preferable.

Abstract: A novel method for manufacturing a positive electrode active material is provided. In the method, an acid solution is formed by mixing an aqueous solution containing nickel, cobalt, and manganese with an aqueous solution containing a first additive element; a composite hydroxide containing nickel, cobalt, manganese, and the first additive element is formed by a reaction between the acid solution and an alkaline solution; the composite hydroxide and a lithium source are mixed and heated (first heating) to form a composite oxide; and the composite oxide and a second additive element source are mixed and heated (second heating). The first additive element is at least one of gallium, boron, aluminum, indium, magnesium, and fluorine, and the second additive element is at least one of calcium, gallium, boron, aluminum, indium, magnesium, and fluorine.

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 (G0). 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 (G0), 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 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 (G0). 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 (G0), 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 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 (G0). 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 (G0), 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 is provided. A light-emitting device with high emission efficiency is provided. A light-emitting device with along lifetime is provided. A light-emitting device with low driving voltage is provided. The light-emitting device includes an anode, a cathode, and an EL layer between the anode and the cathode. The EL layer includes a hole-injection layer, a light-emitting layer, and an electron-transport layer. The hole-injection layer is positioned between the anode and the light-emitting layer. The electron-transport layer is positioned between the light-emitting layer and the cathode. The hole-injection layer contains a first substance and a second substance. The first substance is an organic compound which has a hole-transport property and a HOMO level higher than or equal to ?5.7 eV and lower than or equal to ?5.4 eV. The second substance exhibits an electron-accepting property with respect to the first substance.

Abstract: A light-emitting element with a lower voltage and higher emission efficiency is provided. 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, and a difference between them is larger than 0 eV and smaller than or equal to 0.5 eV. Furthermore, the HOMO level of the first organic compound is lower than 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 having a high hole-transport property is provided. A long-lifetime light-emitting element is provided. An organic compound represented by General Formula (G0) is provided. In General Formula (G0), Ar1 represents a substituted or unsubstituted naphthyl group, Ar2 represents a substituted or unsubstituted carbazolyl group, Ar3 represents a substituted or unsubstituted fluorenyl group or a substituted or unsubstituted spirofluorenyl group, and ?1 and ?2 each independently represent a substituted or unsubstituted phenylene group or a substituted or unsubstituted biphenyldiyl group.

Abstract: A light-emitting element with a lower voltage and higher emission efficiency is provided. 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, and a difference between them is larger than 0 eV and smaller than or equal to 0.5 eV. Furthermore, the HOMO level of the first organic compound is lower than 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 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 (G0). 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 (G0), 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 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 (G0). 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 (G0), 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 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 (G0). 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 (G0), 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 light-emitting element with a lower voltage and higher emission efficiency is provided. 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, and a difference between them is larger than 0 eV and smaller than or equal to 0.5 eV. Furthermore, the HOMO level of the first organic compound is lower than 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 having a high hole-transport property is provided. A long-lifetime light-emitting element is provided. An organic compound represented by General Formula (G0) is provided. In General Formula (G0), Ar1 represents a substituted or unsubstituted naphthyl group, Ar2 represents a substituted or unsubstituted carbazolyl group, Ar3 represents a substituted or unsubstituted fluorenyl group or a substituted or unsubstituted spirofluorenyl group, and ?1 and ?2 each independently represent a substituted or unsubstituted phenylene group or a substituted or unsubstituted biphenyldiyl group.

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 (G0). 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 (G0), 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 organic compound having a high hole-transport property is provided. A long-lifetime light-emitting element is provided. An organic compound represented by General Formula (G0) is provided. In General Formula (G0), Ar1 represents a substituted or unsubstituted naphthyl group, Ar2 represents a substituted or unsubstituted carbazolyl group, Ar3 represents a substituted or unsubstituted fluorenyl group or a substituted or unsubstituted spirofluorenyl group, and ?1 and ?2 each independently represent a substituted or unsubstituted phenylene group or a substituted or unsubstituted biphenyldiyl group.