Light-emitting element, light-emitting device, electronic device, lighting device, and organometallic complex
In a light-emitting element, a layer including an organic compound includes a light-emitting layer; the light-emitting layer includes a tris iridium complex; and on the assumption that there is a rectangle which covers the iridium complex and in which at least one atom of the iridium complex is located over each of four sides when the iridium complex is two-dimensionally seen from a direction of a C3 symmetry axis of the iridium complex, A×B/C 2 is greater than or equal to 2.5, where A represents a maximum length of a long side of the rectangle, B represents a length of a short side of the rectangle when the length of the long side of the rectangle is A, and C represents a width in the direction of the C3 symmetry axis when the iridium complex is two-dimensionally seen from a normal direction of the C3 symmetry axis.
1. A light-emitting element comprising:
a first electrode;
a second electrode; and
a layer including an organic compound,
wherein the layer including an organic compound is located between the first electrode and the second electrode,
wherein the layer including an organic compound comprises a light-emitting layer,
wherein the light-emitting layer comprises a host material comprising a first organic compound comprising a pyrimidine skeleton,
wherein the light-emitting layer comprises a tris iridium complex,
wherein on the assumption that there is a rectangle which covers the iridium complex and in which at least one atom of the iridium complex is located over each of four sides when the iridium complex is two-dimensionally seen from a direction of a C3 symmetry axis of the iridium complex, A×B/C 2 is greater than or equal to 3.0 and lower than or equal to 5.7, where A represents a maximum length of a long side of the rectangle, B represents a length of a short side of the rectangle when the length of the long side of the rectangle is A, and C represents a width in the direction of the C3 symmetry axis when the iridium complex is two-dimensionally seen from a normal direction of the C3 symmetry axis, and
wherein the iridium complex comprises a ligand comprising a triazole skeleton or a ligand comprising an imidazole skeleton.
2. The light-emitting element according to claim 1 , wherein the A×B/C 2 is 4.3.
3. A light-emitting device comprising:
the light-emitting element according to claim 1 ; and
at least one of a transistor and a substrate.
4. An electronic device comprising:
the light-emitting device according to claim 3 ; and
at least one of a sensor, an operation button, a speaker, and a microphone.
5. A lighting device comprising:
the light-emitting device according to claim 3 ; and
a housing.
6. The light-emitting element according to claim 1 , wherein the first organic compound further comprises a carbazole skeleton.
7. The light-emitting element according to claim 1 , wherein the host material further comprises a second organic compound.
8. The light-emitting element according to claim 7 , wherein the second organic compound comprises a carbazole skeleton.
9. The light-emitting element according to claim 7 , wherein a weight ratio of the host material to the tris iridium complex is 1:0.10 or higher and 1:0.125 or lower.
10. The light-emitting element according to claim 1 , wherein the light-emitting element emits blue light.
11. The light-emitting element according to claim 1 ,
wherein an orientation parameter of the tris iridium complex is lower than or equal to 0.25.
12. An organometallic complex represented by a following formula:
13. A light-emitting element comprising:
a first electrode;
a second electrode; and
a layer including an organic compound,
wherein the layer including an organic compound is located between the first electrode and the second electrode,
wherein the layer including an organic compound comprises a light-emitting layer,
wherein the light-emitting layer comprises a host material comprising a first organic compound comprising a pyrimidine skeleton,
wherein the light-emitting layer comprises a tris iridium complex,
wherein on the assumption that there is a rectangle which covers the iridium complex and in which at least one atom of the iridium complex is located over each of four sides when the iridium complex is two-dimensionally seen from a direction of a C3 symmetry axis of the iridium complex, A×B/C 2 is greater than or equal to 3.0 and lower than or equal to 4.3, where A represents a maximum length of a long side of the rectangle, B represents a length of a short side of the rectangle when the length of the long side of the rectangle is A, and C represents a width in the direction of the C3 symmetry axis when the iridium complex is two-dimensionally seen from a normal direction of the C3 symmetry axis, and
wherein the iridium complex comprises a ligand comprising a pyridine skeleton.
14. The light-emitting element according to claim 13 ,
wherein the first organic compound and/or the second organic compound comprise a carbazole skeleton.
15. The light-emitting element according to claim 14 , wherein the first organic compound comprises a pyrimidine skeleton.
16. The light-emitting element according to claim 13 , wherein the light-emitting element emits blue light.
17. A light-emitting device comprising:
the light-emitting element according to claim 13 ; and
at least one of a transistor and a substrate.