Patent ID: 8203262

Claim:
A light-emitting element comprising: a first electrode; a second electrode; and a light-emitting layer and a control layer between the first electrode and the second electrode, the control layer being in contact with the light-emitting layer, wherein: the control layer includes a first organic compound and a second organic compound; the first organic compound is included more than the second organic compound; the first organic compound is an organic compound having an electron-transporting property; a lowest unoccupied molecular orbital level (LUMO level) of the second organic compound is deeper than the lowest unoccupied molecular orbital level (LUMO level) of the first organic compound; a value of a parameter X obtained by an expression (1) is in the range of from 5×10 −4 to 2×10 −2 ; and X = 1 L ⁢ { exp ⁡ ( - Δ ⁢ ⁢ E kT ) } C 3 ( 1 ) ΔE is an energy difference [eV] between the LUMO level of the first organic compound and the LUMO level of the second organic compound, C is a molar fraction [dimensionless term] of the second organic compound in the control layer, L is a thickness [nm] of the control layer, k is a Boltzmann constant (=8.61×10 −5 [eV·K −1 ]), and T is a temperature (=300[K]), wherein the second organic compound is a quinoxaline derivative.