LIGHT-EMITTING ELEMENT, DISPLAY DEVICE, ELECTRONIC DEVICE, AND LIGHTING DEVICE

摘要

An embodiment of the present invention provides a light emitting element which includes a fluorescence material and has high luminous efficiency. The light emitting device contains the fluorescence material and a host material. The host material contains a first organic compound and a second organic compound. The first organic compound and the second organic compound have a function of forming exciplex. The occupied rate of a delayed fluorescence element in luminescence of the exciplex is 5% or more. The delayed fluorescence element has a delayed fluorescence element of which the phosphor life is in the range of 10 and 50 s.