Abstract: Disclosed is a light-emitting element with a microcavity structure which is capable of amplifying a plurality of wavelengths to give emission of a desired color. The light-emitting element includes a pair of electrodes and an EL layer having a light-emitting substance interposed between the pair of electrodes. One of the pair of electrodes gives a reflective surface and the other electrode gives a semi-reflective surface. The light-emitting element is arranged so that the emission of the light-emitting substance covers at least two wavelengths ? and an optical path length L between the reflective surface and the semi-reflective surface satisfies an equation L=n?/2 where n is an integer greater than or equal to 2.

Abstract: First to third light-emitting elements each including a reflection electrode layer, a transflective electrode layer, and a light-emitting layer provided therebetween are provided. In the first light-emitting element, the light-emitting layer is in contact with the reflection electrode layer and the transflective electrode layer. In the second light-emitting element, a first transparent electrode layer is in contact with the reflection electrode layer, the light-emitting layer is in contact with the first transparent electrode layer and the transflective electrode layer. In the third light-emitting element, a second transparent electrode layer is in contact with the reflection electrode layer, the light-emitting layer is in contact with the second transparent electrode layer and the transflective electrode layer. The first transparent electrode layer is different form the second transparent electrode layer in thickness.

Abstract: To provide a display device with low power consumption. The display device includes a plurality of pixels each having a light-emitting element having a structure in which light emitted from a light-emitting layer is resonated between a reflective electrode and a light-transmitting electrode, wherein no color filter layers are provided or color filter layers with high transmittance are provided in pixels for light with relatively short wavelengths (e.g., pixels for blue and/or green), and a color filter layer is selectively provided in pixels for light with a long wavelength (e.g., pixels for red), and thereby maintaining color reproducibility and consuming less power.

Abstract: A light-emitting element having high external quantum efficiency is provided. A light-emitting element having a long lifetime is provided. A light-emitting element includes a light-emitting layer between a pair of electrodes. The light-emitting layer contains at least a phosphorescent compound, a first organic compound (host material) having an electron-transport property, and a second organic compound (assist material) having a hole-transport property. The light-emitting layer has a stacked-layer structure including a first light-emitting layer and a second light-emitting layer, and the first light-emitting layer contains a higher proportion of the second organic compound than the second light-emitting layer. In the light-emitting layer (the first light-emitting layer and the second light-emitting layer), a combination of the first organic compound and the second organic compound forms an exciplex.

Abstract: Provided is a light-emitting device which can emit monochromatic lights with high color purity due to a microcavity effect and which can provide a white light with a broad spectrum when the monochromatic lights are combined. The light-emitting device has a red-, green-, blue-, and yellow-emissive light-emitting elements each of which has a reflective electrode and a semi-transmissive and semi-reflective electrode. The red-, green-, blue-, and yellow-emissive light-emitting elements have the same structure other than the reflective electrode and a layer in contact with the reflective electrode to selectively emit red, green, blue, and yellow lights, respectively. Red, green, and blue color filters are also provided over the red-, green-, blue-, light-emitting elements, respectively. An EL layer is commonly shared by the red-, green-, blue-, and yellow-emissive light-emitting elements, and the semi-transmissive and semi-reflective electrode covers an edge portion of the EL layer.

Abstract: Provided is a light-emitting device which can emit monochromatic light with high purity due to a microcavity effect and which can emit white light in the case of a combination of monochromatic light. Provided is a high-definition light-emitting device. Provided is a light-emitting device with low power consumption. In a light-emitting device with a white-color filter top emission structure, one pixel is formed of four sub-pixels of RBGY, an EL layer includes a first light-emitting substance which emits blue light and a second light-emitting substance which emits light corresponding to a complementary color of blue, and a semi-transmissive and semi-reflective electrode (an upper electrode) is formed so as to cover an edge portion of the EL layer.

Abstract: A light-emitting element with a high current efficiency is provided. A low-power consumption light-emitting device is also provided. In addition, low-power consumption electronic device and lighting device are provided. The light-emitting element includes an EL layer between a pair of electrodes. The EL layer includes a light-emitting layer. The light-emitting layer includes a first light-emitting layer and a second light-emitting layer. The emission peak of the second light-emitting layer is at a shorter wavelength than that of the first light-emitting layer. The first light-emitting layer includes a host material and a guest material. The LUMO level of the guest material is in the range of ±0.1 eV of the LUMO level of the host material.

Abstract: A technique of manufacturing a display device with high productivity is provided. In addition, a high-definition display device with high color purity is provided. By adjusting the optical path length between an electrode having a reflective property and a light-emitting layer by the central wavelength of a wavelength range of light passing through a color filter layer, the high-definition display device with high color purity is provided without performing selective deposition of light-emitting layers. In a light-emitting element, a plurality of light-emitting layers emitting light of different colors are stacked. The closer the light-emitting layer is to the electrode having a reflective property, the longer the wavelength of light emitted from the light-emitting layer is.

Abstract: A technique of manufacturing a display device with high productivity is provided. In addition, a high-definition display device with high color purity is provided. By adjusting the optical path length between an electrode having a reflective property and a light-emitting layer by the central wavelength of a wavelength range of light passing through a color filter layer, the high-definition display device with high color purity is provided without performing selective deposition of light-emitting layers. In a light-emitting element, a plurality of light-emitting layers emitting light of different colors are stacked. The closer the light-emitting layer is positioned to the electrode having a reflective property, the shorter the wavelength of light emitted from the light-emitting layer is.

Abstract: A light-emitting element with which a reduction in power consumption and an improvement in productivity of a display device can be achieved is provided. A technique of manufacturing a display device with high productivity is provided. The light-emitting element includes an electrode having a reflective property, and a first light-emitting layer, a charge generation layer, a second light-emitting layer, and an electrode having a light-transmitting property stacked in this order over the electrode having a reflective property. The optical path length between the electrode having a reflective property and the first light-emitting layer is one-quarter of the peak wavelength of the emission spectrum of the first light-emitting layer. The optical path length between the electrode having a reflective property and the second light-emitting layer is three-quarters of the peak wavelength of the emission spectrum of the second light-emitting layer.

Abstract: Disclosed is a light-emitting element with a microcavity structure which is capable of amplifying a plurality of wavelengths to give emission of a desired color. The light-emitting element includes a pair of electrodes and an EL layer having a light-emitting substance interposed between the pair of electrodes. One of the pair of electrodes gives a reflective surface and the other electrode gives a semi-reflective surface. The light-emitting element is arranged so that the emission of the light-emitting substance covers at least two wavelengths ? and an optical path length L between the reflective surface and the semi-reflective surface satisfies an equation L=n?/2 where n is an integer greater than or equal to 2.

Abstract: A light-emitting element having high external quantum efficiency is provided. A light-emitting element having a long lifetime is provided. A light-emitting element includes a light-emitting layer between a pair of electrodes. The light-emitting layer contains at least a phosphorescent compound, a first organic compound (host material) having an electron-transport property, and a second organic compound (assist material) having a hole-transport property. The light-emitting layer has a stacked-layer structure including a first light-emitting layer and a second light-emitting layer, and the first light-emitting layer contains a higher proportion of the second organic compound than the second light-emitting layer. In the light-emitting layer (the first light-emitting layer and the second light-emitting layer), a combination of the first organic compound and the second organic compound forms an exciplex.

Abstract: A technique of manufacturing a display device with high productivity is provided. In addition, a high-definition display device with high color purity is provided. By adjusting the optical path length between an electrode having a reflective property and a light-emitting layer by the central wavelength of a wavelength range of light passing through a color filter layer, the high-definition display device with high color purity is provided without performing selective deposition of light-emitting layers. In a light-emitting element, a plurality of light-emitting layers emitting light of different colors are stacked. The closer the light-emitting layer is to the electrode having a reflective property, the longer the wavelength of light emitted from the light-emitting layer is.

Abstract: A light-emitting element with which a reduction in power consumption and an improvement in productivity of a display device can be achieved is provided. A technique of manufacturing a display device with high productivity is provided. The light-emitting element includes an electrode having a reflective property, and a first light-emitting layer, a charge generation layer, a second light-emitting layer, and an electrode having a light-transmitting property stacked in this order over the electrode having a reflective property. The optical path length between the electrode having a reflective property and the first light-emitting layer is one-quarter of the peak wavelength of the emission spectrum of the first light-emitting layer. The optical path length between the electrode having a reflective property and the second light-emitting layer is three-quarters of the peak wavelength of the emission spectrum of the second light-emitting layer.

Abstract: A technique of manufacturing a display device with high productivity is provided. In addition, a high-definition display device with high color purity is provided. By adjusting the optical path length between an electrode having a reflective property and a light-emitting layer by the central wavelength of a wavelength range of light passing through a color filter layer, the high-definition display device with high color purity is provided without performing selective deposition of light-emitting layers. In a light-emitting element, a plurality of light-emitting layers emitting light of different colors are stacked. The closer the light-emitting layer is positioned to the electrode having a reflective property, the shorter the wavelength of light emitted from the light-emitting layer is.

Abstract: A light-emitting element with improved heat resistance is provided without losing its advantages such as thinness, lightness, and low power consumption. A light-emitting element is provided which includes a first electrode, a second electrode, and an EL layer between the first electrode and the second electrode, in which the EL layer includes a layer containing a condensed aromatic compound or a condensed heteroaromatic compound, and a layer containing 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen) in contact with the layer containing the condensed aromatic compound or the condensed heteroaromatic compound.

Abstract: A light-emitting panel can be manufactured in which a first light-emitting element emits light having high brightness and a pale color and causing less eyestrain even in the case of long time, a second light-emitting element emits light of a bright red color, a third light-emitting element emits green light, and a fourth light-emitting element emits blue light. Further, a layer transmitting light of a specific color (e.g., a color filter) is not provided in all the light-emitting elements except the second light-emitting element; thus, light emitted from the layer containing a light-emitting organic compound can be efficiently used. As a result, a light-emitting panel which is capable of bright, full-color light emission and whose power consumption is reduced can be provided.

Abstract: A light-emitting element, a light-emitting module, a light-emitting panel, or a light-emitting device in which loss due to electrical resistance is reduced is provided. The present invention focuses on a surface of an electrode containing a metal and on a layer containing a light-emitting organic compound. The layer containing a light-emitting organic compound is provided between one electrode including a first metal, whose surface is provided with a conductive inclusion, and the other electrode.

Abstract: One object is to provide a light-emitting element which overcomes the problems of electrical characteristics and a light reflectivity have been solved. The light-emitting element is manufactured by forming a first electrode including aluminum and nickel over a substrate; by forming a layer including a composite material in which a metal oxide is contained in an organic compound so as to be in contact with the first electrode after heat treatment is performed with respect to the first electrode; by forming a light-emitting layer over the layer including a composite material; and by forming a second electrode which has a light-transmitting property over the light-emitting layer. Further, the first electrode is preferably formed to include the nickel equal to or greater than 0.1 atomic % and equal to or less than 4.0 atomic %.

Abstract: A light-emitting panel includes at least a first light-emitting element emits and a second light-emitting element, each light-emitting element having, between a reflective film and a semi-transmissive/semi-reflective film, a layer including an optical adjustment layer and a light-emitting organic compound interposed between a pair of electrodes. One of the light-emitting elements further includes a layer transmitting red light provided over the corresponding semi-transmissive/semi-reflective film. The layer having the organic compound emits light having a wavelength between 600 nm and 800 nm, and light having a wavelength between 400 nm and 600 nm.