| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem that when a phosphorescent compound (e.g., blue phosphorescent compound) having high light-emitting energy is used as a guest material, a T1 level required for a host material becomes higher compared to a case where a phosphorescent compound having low light-emitting energy is used, thereby occurring a chemically unstable state.SOLUTION: A light-emitting element includes a light-emitting layer in which light emission obtained based on a host material and a guest material exhibits attenuation curves of multiple components when exhibiting a relationship between a relative light-emitting intensity and a light-emitting time, and by shortening (preferably, 15 μsec or less) a light-emitting time of the component whose attenuation curve takes the longest time until a relative light-emitting intensity decreases to 1/100 to a degree non-competitive with extinction of the host material, efficient luminous efficiency can be ensured. |
