LIGHT EMITTING ELEMENT, LIGHT EMITTING DEVICE, AND ELECTRONIC EQUIPMENT

摘要

PROBLEM TO BE SOLVED: To provide a light emitting element having an improved lifetime.

SOLUTION: This light emitting element includes a first luminescent layer formed on a first electrode, a second luminescent layer formed on the first luminescent layer in contact with the first luminescent layer, and a second electrode formed on the second luminescent layer. The first luminescent layer includes a first luminescent substance and a hole transporting organic compound, and the second luminescent layer includes a second luminescent substance and an electron transporting organic compound. The substances are selected to satisfy the following: differences between the LUMO (lowest unoccupied molecular orbital) levels of the first and second luminescent substances and the LUMO level of the electron transporting organic compound are not more than 0.2 eV respectively, differences between the HOMO level of the hole transporting organic compound and the highest occupied molecular orbital (HOMO) levels of the first and second luminescent substances are not more than 0.2 eV respectively, and a difference between the LUMO level of the hole transporting organic compound and the LUMO level of the first luminescent substance is larger than 0.3 eV.

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