Light-emitting element, display device, electronic device, and lighting device
An object is to provide a light-emitting element with high emission efficiency. The light-emitting element contains first to third organic compounds. The first organic compound has a function of converting triplet excitation energy into light. The second organic compound has a benzofuropyrimidine skeleton or a benzothienopyrimidine skeleton. The third organic compound is a fluorescent compound. Light emitted from the light-emitting element is light emitted from the third organic compound that receives excitation energy from the first organic compound or from an exciplex formed by the first and second organic compounds.
1. A A light-emitting device comprising:
a first electrode;
a light-emitting layer over the first electrode, the light-emitting layer comprising:
a first organic compound configured to emit thermally activated delayed fluorescence;
a second organic compound having one of a benzofuropyrimidine skeleton and a benzothienopyrimidine skeleton; and
a third organic compound configured to convert singlet excitation energy into light; and
a second electrode over the light-emitting layer,
wherein light emitted from the light-emitting layer comprises light emitted from the third organic compound, and
wherein an emission spectrum of a mixture of the first organic compound and the second organic compound overlaps with an absorption spectrum of the third organic compound.
2. The light-emitting device according to claim 1 , wherein the first organic compound is configured to supply excitation energy to the third organic compound.
3. The light-emitting device according to claim 1 ,
wherein the benzofuropyrimidine skeleton is a benzofuro[3,2-d]pyrimidine skeleton, and
wherein the benzothienopyrimidine skeleton is a benzothieno[3,2-d]pyrimidine skeleton.
4. The light-emitting device according to claim 3 ,
wherein the benzofuro[3,2-d]pyrimidine skeleton has one of a substituent at 4-position and a substituent at 8-position, and
wherein the benzothieno[3,2-d]pyrimidine skeleton has one of a substituent at 4-position and a substituent at 8-position.
5. The light-emitting device according to claim 1 , wherein the first organic compound has an emission quantum yield higher than or equal to 0% and lower than or equal to 40% at room temperature.
6. The light-emitting device according to claim 1 , wherein the third organic compound emits fluorescence.
7. A display device comprising:
the light-emitting device according to claim 1 ; and
at least one of a color filter and a transistor.
8. An electronic device comprising:
the display device according to claim 7 ; and
at least one of a housing and a touch sensor.
9. A lighting device comprising:
the light-emitting device according to claim 1 ; and
at least one of a housing and a touch sensor.
10. The light-emitting device according to claim 1 , wherein the emission spectrum of the mixture of the first organic compound and the second organic compound overlaps with an absorption band on the longest wavelength side of the absorption spectrum of the third organic compound.
11. A light-emitting device comprising:
a first electrode;
a light-emitting layer over the first electrode, the light-emitting layer comprising:
a first organic compound configured to emit thermally activated delayed fluorescence;
a second organic compound having one of a benzofuropyrimidine skeleton and a benzothienopyrimidine skeleton; and
a third organic compound configured to convert singlet excitation energy into light; and
a second electrode over the light-emitting layer,
wherein light emitted from the light-emitting layer comprises light emitted from the third organic compound, and
wherein an emission peak of a mixture of the first organic compound and the second organic compound overlaps with an absorption spectrum of the third organic compound.
12. The light-emitting device according to claim 11 , wherein the first organic compound is configured to supply excitation energy to the third organic compound.
13. The light-emitting device according to claim 11 ,
wherein the benzofuropyrimidine skeleton is a benzofuro[3,2-d]pyrimidine skeleton, and
wherein the benzothienopyrimidine skeleton is a benzothieno[3,2-d]pyrimidine skeleton.
14. The light-emitting device according to claim 13 ,
wherein the benzofuro[3,2-d]pyrimidine skeleton has one of a substituent at 4-position and a substituent at 8-position, and
wherein the benzothieno[3,2-d]pyrimidine skeleton has one of a substituent at 4-position and a substituent at 8-position.
15. The light-emitting device according to claim 11 , wherein the first organic compound has an emission quantum yield higher than or equal to 0% and lower than or equal to 40% at room temperature.
16. The light-emitting device according to claim 11 , wherein the third organic compound emits fluorescence.
17. A display device comprising:
the light-emitting device according to claim 11 ; and
at least one of a color filter and a transistor.
18. An electronic device comprising:
the display device according to claim 17 ; and
at least one of a housing and a touch sensor.
19. A lighting device comprising:
the light-emitting device according to claim 11 ; and
at least one of a housing and a touch sensor.
20. The light-emitting device according to claim 11 , wherein the emission peak of the mixture of the first organic compound and the second organic compound overlaps with an absorption band on the longest wavelength side of the absorption spectrum of the third organic compound.