Light-emitting element, display device, electronic device, and lighting device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsTakahiro ISHISONE, Satoshi SEO
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Abstract
A light-emitting element with high luminous efficiency is provided. The light-emitting element contains a first organic compound and a second organic compound. The first and second organic compounds form an exciplex. The first organic compound emits no fluorescence but phosphorescence at a temperature ranging from low temperature to normal temperature. The luminescence quantum yield of the first organic compound is higher than or equal to 0% and lower than or equal to 40% at room temperature. Light emitted from the light-emitting element includes light emitted from an exciplex formed by the first organic compound and the second organic compound.
Claims21
A light-emitting element comprising a light-emitting layer comprising a first organic compound and a second organic compound,
- wherein a LUMO level of one of the first organic compound and the second organic compound is higher than or equal to a LUMO level of the other of the first organic compound and the second organic compound,
- wherein a HOMO level of the one of the first organic compound and the second organic compound is higher than or equal to a HOMO level of the other of the first organic compound and the second organic compound,
- wherein a combination of the first organic compound and the second organic compound is capable of forming an exciplex,
- wherein the first organic compound is capable of converting triplet excitation energy into light emission,
- wherein the first organic compound has a luminescence quantum yield higher than or equal to 0% and lower than or equal to 40% at room temperature, and
- wherein light emitted from the light-emitting layer compries light emitted from the exciplex.
A light-emitting element comprising a light-emitting layer comprising a first organic compound and a second organic compound,
- wherein a LUMO level of one of the first organic compound and the second organic compound is higher than or equal to a LUMO level of the other of the first organic compound and the second organic compound,
- wherein a HOMO level of the one of the first organic compound and the second organic compound is higher than or equal to a HOMO level of the other of the first organic compound and the second organic compound,
- wherein a combination of the first organic compound and the second organic compound is capable of forming an exciplex,
- wherein the first organic compound is capable of not emitting fluorescence,
- wherein the first organic compound is capable of emitting phosphorescence,
- wherein the first organic compound has a luminescence quantum yield higher than or equal to 0% and lower than or equal to 40% at room temperature, and
- wherein light emitted from the light-emitting layer comprises light emitted from the exciplex.
A light-emitting element comprising a light-emitting layer comprising a first organic compound and a second organic compound,
- wherein a LUMO level of one of the first organic compound and the second organic compound is higher than or equal to a LUMO level of the other of the first organic compound and the second organic compound,
- wherein a HOMO level of the one of the first organic compound and the second organic compound is higher than or equal to a HOMO level of the other of the first organic compound and the second organic compound,
- wherein a combination of the first organic compound and the second organic compound is capable of forming an exciplex,
- wherein the first organic compound comprises Ru, Rh, Pd, Os, Ir, or Pt,
- wherein the first organic compound has a luminescence quantum yield higher than or equal to 0% and lower than or equal to 40% at room temperature, and
- wherein light emitted from the light-emitting layer comprises light emitted from the exciplex.
Dependencies are inferred from the claim text.