US Patent 10062861 Light-emitting element, display device, electronic device, and lighting device

A light-emitting element with high emission efficiency which includes fluorescent materials is provided. The light-emitting element includes a first light-emitting layer and a second light-emitting layer. The first light-emitting layer includes a first fluorescent material and a first host material, and the second light-emitting layer includes a second fluorescent material and a second host material. The second host material includes a first organic compound and a second organic compound. The first organic compound and the second organic compound form an exciplex. A singlet excited energy level of the first host material is higher than a singlet excited energy level of the first fluorescent material, and a triplet excited energy level of the first host material is lower than a triplet excited energy level of the first fluorescent material.