Light-Emitting Element, Light-Emitting Device, Electronic Device, Lighting Device, and Lighting System

Abstract

A light-emitting element that contains a fluorescent compound, which has high efficiency is provided. A light-emitting element in which the proportion of delayed fluorescence to the total light emitted from the light-emitting element is higher than that in a conventional light-emitting element is provided. Emission efficiency of the light-emitting element containing a fluorescent compound can be improved by increasing the probability of TTA caused by an organic compound in an EL layer, converting energy of triplet excitons, which does not contribute to light emission, into energy of singlet excitons, and making the fluorescent compound emit light by energy transfer of the singlet excitons.

What is claimed is: 
     
         1 . Alight-emitting element comprising:
 an EL layer between an anode and a cathode,   wherein the EL layer includes a light-emitting layer,   wherein the light-emitting layer includes a first organic compound, and   wherein a difference between a T 1  level of the first organic compound and one or more of T n  levels of the first organic compound is less than the sum of the T 1  level and 0.6 eV.