A multicolor light-emitting element using fluorescence and phosphorescence, which has a small number of manufacturing steps owing to a relatively small number of layers to be formed and is advantageous for practical application can be provided. In addition, a multicolor light-emitting element using fluorescence and phosphorescence, which has favorable emission efficiency is provided. A light-emitting element which includes a light-emitting layer having a stacked-layer structure of a first light-emitting layer exhibiting light emission from a first exciplex and a second light-emitting layer exhibiting phosphorescence is provided.

The present invention relates to organic electroluminescent devices including a light-emitting layers B including a TADF material, an excitation energy transfer component EET-2, a small full width at half maximum (FWHM) emitter S.sup.B emitting blue light with an FWHM of less than or equal to 0.25 eV, and a host material H.sup.B. Furthermore, the present invention relates to a method for generating blue light by means of an organic electroluminescent device according to the present invention.

The present invention relates to organic electroluminescent devices including one or more light-emitting layers B, each of which is composed of one or more sublayers including as a whole one or more excitation energy transfer components EET-1, one or more excitation energy transfer components EET-2, one or more small full width at half maximum (FWHM) emitters S.sup.B emitting light with an FWHM of less than or equal to 0.25 eV. Furthermore, the present invention relates to a method for generating light by means of an organic electroluminescent device according to the present invention.

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, and a first layer. The first layer is positioned between the first electrode and the second electrode. The first layer includes a light-emitting material, a first organic compound, and a first material. The light-emitting material has a function of emitting fluorescent light. The absorption spectrum of the light-emitting material has the longest-wavelength edge at a first wavelength. The first organic compound has a function of converting triplet excitation energy into light emission. The spectrum of the emitted light has the shortest-wavelength edge at a second wavelength. The second wavelength is positioned at a wavelength shorter than the first wavelength. The first organic compound includes a first substituent R1. The first substituent R1 is any of an alkyl group, a substituted or unsubstituted cycloalkyl group, and a trialkylsilyl group. The first material has a function of emitting delayed fluorescent light at room temperature. The difference between the HOMO level and the LUMO level of the first material is smaller than the difference between the HOMO level and the LUMO level of the first organic compound.

A light-emitting device with favorable carrier balance is provided. The light-emitting device includes a light-emitting layer between a first electrode and a second electrode. The light-emitting layer includes at least a first substance and a light-emitting substance, the first substance includes an organic compound having one or more of a carbazole ring, an aromatic amine skeleton, and a ?-electron deficient heteroaromatic ring, a luminescence lifetime of delayed fluorescence caused by photoexcitation of the light-emitting substance is shorter at a first temperature than at a second temperature, the first temperature is lower than the second temperature, and the first temperature and the second temperature are each higher than or equal to 10 K and lower than or equal to 300 K.

A multicolor light-emitting element using fluorescence and phosphorescence, which has a small number of manufacturing steps owing to a relatively small number of layers to be formed and is advantageous for practical application can be provided. In addition, a multicolor light-emitting element using fluorescence and phosphorescence, which has favorable emission efficiency is provided. A light-emitting element which includes a light-emitting layer having a stacked-layer structure of a first light-emitting layer exhibiting light emission from a first exciplex and a second light-emitting layer exhibiting phosphorescence is provided.

A light emitting device of an embodiment includes a first light emitting unit including a first emission layer, and a second light emitting unit including a second emission layer. The first emission layer includes a first host, a phosphorescence sensitizer, a first fluorescence dopant, the second emission layer includes a second host which is different from the first host, and a second fluorescence dopant, the first fluorescence dopant has a highest occupied molecular orbital (HOMO) energy level of about ?5.2 eV or less, and the second fluorescence dopant has a HOMO energy level of about ?5.2 eV or more.

An organic light-emitting device which including a first electrode, a second electrode facing the first electrode, and an emission layer disposed between the first electrode and the second electrode, wherein an emission layer includes a first material, a second material, and a third material satisfying certain conditions.

A light-emitting element which uses a plurality of kinds of light-emitting dopants emitting light in a balanced manner and has high emission efficiency is provided. Further, a light-emitting device, a display device, an electronic device, and a lighting device each having reduced power consumption by using the above light-emitting element are provided. A light-emitting element which includes a plurality of light-emitting layers including different phosphorescent materials is provided. In the light-emitting element, the light-emitting layer which includes a light-emitting material emitting light with a long wavelength includes two kinds of carrier-transport compounds having properties of transporting carriers with different polarities. Further, in the light-emitting element, the triplet excitation energy of a host material included in the light-emitting layer emitting light with a short wavelength is higher than the triplet excitation energy of at least one of the carrier-transport compounds.

A light-emitting element is provided. The light-emitting element includes first and second electrodes and an EL layer therebetween. The EL layer includes a light-emitting layer containing first and second substances. The amount of the first substance is larger than that of the second substance. The second substance emits light. Average transition dipole moments of the second substance are divided into three components in x-, y-, and z-directions which are orthogonal to each other. Components parallel to the first or second electrode are assumed to be the components in the x- and y-directions, and a component perpendicular to the first or second electrode is assumed to be the component in the z-direction. The proportion of the component in the z-direction is represented by a, which is less than or equal to 0.2.