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 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 convert triplet excitation energy into light;
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 the first organic compound comprises one of Ru, Rh, Pd, Os, Ir and Pt.
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 is capable of emitting phosphorescence.
6. 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.
7. The light-emitting device according to claim 1 , wherein the third organic compound emits fluorescence.
8. The light-emitting device according to claim 1 , wherein a difference between the lowest singlet excitation energy and the lowest triplet excitation energy of the first organic compound is greater than or equal to 0 eV and less than or equal to 0.2 eV.
9. A display device comprising:
the light-emitting device according to claim 1 ; and
at least one of a color filter and a transistor.
10. An electronic device comprising:
the display device according to claim 9 ; and
at least one of a housing and a touch sensor.
11. A lighting device comprising:
the light-emitting device according to claim 1 ; and
at least one of a housing and a touch sensor.
12. 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 convert triplet excitation energy into light;
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 the first organic compound and the second organic compound are capable of forming an exciplex, and
wherein light emitted from the light-emitting layer comprises light emitted from the third organic compound.
13. The light-emitting device according to claim 12 , wherein the exciplex is configured to supply excitation energy to the third organic compound.
14. The light-emitting device according to claim 12 ,
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.
15. The light-emitting device according to claim 14 ,
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.
16. The light-emitting device according to claim 12 , wherein the first organic compound comprises one of Ru, Rh, Pd, Os, Ir and Pt.
17. The light-emitting device according to claim 12 , wherein the first organic compound is capable of emitting phosphorescence.
18. The light-emitting device according to claim 12 , wherein an emission spectrum of the exciplex partly overlaps an absorption band on the longest wavelength side of an absorption spectrum of the third organic compound.
19. The light-emitting device according to claim 12 , 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.
20. The light-emitting device according to claim 12 , wherein the exciplex is configured to emit light with higher emission efficiency than emission efficiency of the first organic compound.
21. The light-emitting device according to claim 12 , wherein the third organic compound emits fluorescence.
22. The light-emitting device according to claim 12 , wherein a difference between the lowest singlet excitation energy and the lowest triplet excitation energy of the first organic compound is greater than or equal to 0 eV and less than or equal to 0.2 eV.
23. A display device comprising:
the light-emitting device according to claim 12 ; and
at least one of a color filter and a transistor.
24. An electronic device comprising:
the display device according to claim 23 ; and
at least one of a housing and a touch sensor.
25. A lighting device comprising:
the light-emitting device according to claim 12 ; and
at least one of a housing and a touch sensor.