Light-emitting element having an organic compound and a transition metal forming SOMO
View Patent ↗A reliable light-emitting element with low driving voltage is provided. The light-emitting element includes an electron-injection layer between a cathode and a light-emitting layer. The electron-injection layer is a mixed film of a transition metal and an organic compound having an unshared electron pair. An atom of the transition metal and the organic compound form SOMO.
1. A light-emitting element comprising:
a light-emitting layer between an anode and a cathode; and
a first layer between the light-emitting layer and the cathode,
wherein the first layer includes a first organic compound and a transition metal,
wherein the first organic compound includes an unshared electron pair, and
wherein the first organic compound and the transition metal form SOMO.
2. The light-emitting element according to claim 1 ,
wherein the transition metal is a metal belonging to Group 5, Group 7, Group 9, or Group 11 in the periodic table.
3. The light-emitting element according to claim 1 ,
wherein the first organic compound includes an electron deficient heteroaromatic ring.
4. The light-emitting element according to claim 3 ,
wherein the electron deficient heteroaromatic ring includes at least one of a pyridine ring, a diazine ring, and a triazine ring.
5. The light-emitting element according to claim 1 ,
wherein a LUMO level of the first organic compound is higher than or equal to 3.6 eV and lower than or equal to 2.3 eV.
6. The light-emitting element according to claim 1 , further comprising a second layer between the cathode and the first layer,
wherein the second layer includes a second organic compound including an electron deficient heteroaromatic ring.
7. The light-emitting element according to claim 6 ,
wherein a LUMO level of the second organic compound is lower than an energy level of the SOMO.
8. The light-emitting element according to claim 1 ,
wherein the cathode includes a metal which is the same as the transition metal.
9. A display device comprising:
the light-emitting element 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 light-emitting element comprising:
a first light-emitting unit and a second light-emitting unit between an anode and a cathode; and
a first layer between the first light-emitting unit and the second light-emitting unit,
wherein the first layer includes a first organic compound and a transition metal,
wherein the first organic compound includes an unshared electron pair, and
wherein the first organic compound and the transition metal form SOMO.
12. The light-emitting element according to claim 11 , further comprising a charge-generation layer between the first light-emitting unit and the second light-emitting unit,
wherein the first layer and the charge-generation layer are in contact with each other.
13. The light-emitting element according to claim 11 ,
wherein the transition metal is a metal belonging to Group 5, Group 7, Group 9, or Group 11 in the periodic table.
14. The light-emitting element according to claim 11 ,
wherein the first organic compound includes an electron deficient heteroaromatic ring.
15. The light-emitting element according to claim 14 ,
wherein the electron deficient heteroaromatic ring includes at least one of a pyridine ring, a diazine ring, and a triazine ring.
16. The light-emitting element according to claim 11 ,
wherein a LUMO level of the first organic compound is higher than or equal to −3.6 eV and lower than or equal to −2.3 eV.
17. The light-emitting element according to claim 11 , further comprising a second layer between the cathode and the first layer,
wherein the second layer includes a second organic compound including an electron deficient heteroaromatic ring.
18. The light-emitting element according to claim 17 ,
wherein a LUMO level of the second organic compound is lower than an energy level of the SOMO.
19. The light-emitting element according to claim 11 ,
wherein the cathode includes a metal which is the same as the transition metal.
20. A display device comprising:
the light-emitting element according to claim 11 ; and
at least one of a color filter and a transistor.