Patent ID: 8519615

Claim:
A light emitting element comprising a first layer and a second layer containing a light emitting material between a first electrode and a second electrode, wherein the first layer is provided in contact with the first electrode, and the first layer comprises a composite material comprising an organic compound and an inorganic compound, wherein the organic compound is 4,4′-bis[N-(4-biphenylyl)-N-phenylamino]biphenyl, wherein the first electrode contains a material having a work function of 3.5 eV to 5.5 eV, wherein the activation energy for carrier generation in the composite material is 0.01 eV to 0.5 eV, wherein a measured current-voltage characteristic of a thin-film layer formed from the composite material which is interposed between first and second electrodes each having a work function of 3.5 eV to 5.5 eV follows Formula (1) below, J = { A ⁢ ⁢ exp ⁡ ( - ϕ a 2 ⁢ ⁢ kT ) } ⁢ V + BV n ( 1 ) wherein J denotes a current density; V, a voltage; φ a , activation energy for carrier generation in the composite material; k, Boltzmann constant; T, a temperature; n, an integer of 2 to 10; B denotes a parameter determined by inter-electrode distance d and the kind of the composite material; and A is σ 0 /d, wherein σ 0 denotes a material-specific constant.