Patent ID: 8294361

Claim:
An organic electric field light-emitting element, comprising: an anode; a cathode; and an organic layer containing a first organic layer, a second organic layer, and a third organic layer, provided between the anode and the cathode, where the first organic layer, the second organic layer, and the third organic layer are laminated in this order from the side of the anode, wherein the first organic layer contains a first host material and a first hole-transporting phosphorescent material, and the amount of the first host material and the amount of the first host hole-transporting phosphorescent material in the first organic layer are 10% by mass to 90% by mass, and 10% by mass to 90% by mass, respectively, wherein the second organic layer contains a second host material, a second hole-transporting phosphorescent material, and an electron-trapping material, and the amount of the second host material, the amount of the second hole-transporting phosphorescent material, and the amount of the electron-trapping material in the second organic layer are 65% by mass to 96.9% by mass, 3% by mass to 30% by mass, and 0.1% by mass to 5% by mass, respectively, wherein the third organic layer contain a hole-blocking material whose triplet excitation level (T1) is higher than the triplet excitation level (T1) of the second hole-transporting phosphorescent material by at least 0.1 eV, wherein the second host material, the second hole-transporting phosphorescent material, and the electron-trapping material satisfy the relationship expressed by the following formulae: |HOMO t2 |>|HOMO h2 | |HOMO t2 |>|HOMO p2 | |LUMO h2 |+0.25 eV<|LUMO t2 | |LUMO p2 |+0.25 eV<|LUMO t2 | where HOMO t2 is the HOMO level of the electron-trapping material contained in the second organic layer, HOMO h2 is the HOMO level of the second host material, HOMO p2 is the HOMO level of the second hole-transporting phosphorescent material, LUMO h2 is the LUMO level of the second host material, LUMO t2 is the LUMO level of the electron-trapping material contained in the second organic layer, and LUMO p2 is the LUMO level of the second hole-transporting phosphorescent material, and wherein the total of the average thickness of the first organic layer and the average thickness of the second organic layer is at least 40 nm.