Organic electroluminescent device
View Patent ↗An organic electroluminescent device comprising: a pair of electrodes; and at least one organic layer between the pair of electrodes, the at least one organic layer between the pair of electrodes, the at least one organic layer including a luminescent layer, wherein the luminescent layer contains at least one electron injection/transport compound, at least one hole injection/transport compound, and at least one green or blue phosphorescent compound; and the electron injection/transport compound and the hole injection/transport compound each has a minimum triplet exciton energy value which is equal to or more than that of the green or blue phosphorescent compound.
1. An organic electroluminescent device comprising:
a pair of electrodes; and
at least one organic layer between the pair of electrodes, the at least one organic layer including a luminescent layer,
wherein the luminescent layer contains at least one electron injection/transport compound, at least one hole injection/transport compound, and at least one green or blue phosphorescent compound; and the electron injection/transport compound and the hole injection/transport compound each has a minimum triplet exciton energy value which is equal to or more than that of the green or blue phosphorescent compound;
wherein the hole injection/transport compound has an ionization potential of from 5.6 eV to 6.1 eV and the electron injection/transport compound has an electron affinity of from 2.0 eV to 3.5 eV; and
wherein the electron injection/transport compound, the hole injection/transport compound and the green or blue phosphorescent compound each has a T 1 value of 62 kcal/mole or more.
2. The organic electroluminescent device of claim 1 , wherein the green or blue phosphorescent compound is a transition metal complex capable of emitting light via a triplet excitation state.
3. The organic electroluminescent device of claim 1 , wherein phosphorescence obtained from the green or blue phosphorescent compound has a λmax of not longer than 500 nm.
4. The organic electroluminescent device of claim 1 , wherein the hole injection/transport compound is a substituted or unsubstituted pyrrole compound.
5. The organic electroluminescent device of claim 4 , wherein the substituted or unsubstituted pyrrole compound is represented by the formula (1):
wherein R 11 to R 15 each represents a hydrogen atom or a substituent, and the substituents may be bonded to each other to form a ring structure.
6. The organic electroluminescent device of claim 5 , wherein the formula (1) is represented by the formula (3):
wherein R 32 to R 35 each represents a hydrogen atom or a substituent, and the substituents may be bonded to each other to form a ring structure; L 31 represents a connecting group; L 32 represents a di- or more valent connecting group; n 31 represents an integer of 2 or more; and n 32 represents an integer of from 0 to 6.
7. The organic electroluminescent device of claim 1 , wherein the electron injection/transport compound is a heterocyclic compound containing at least two nitrogen atoms.
8. The organic electroluminescent device of claim 7 , wherein the heterocyclic compound containing at least two nitrogen atoms is a compound represented by the formula (2):
wherein R 21 represents a hydrogen atom or a substituent; X 21 , X 22 , X 23 , and X 24 each represents a nitrogen atom or a substituted or unsubstituted carbon atom; and at least one X 22 , X 23 , and X 24 represents a nitrogen atom.
9. The organic electroluminescent device of claim 8 , wherein the formula (2) is represented by the formula (4):
wherein R 41 , R 42 , and R 43 each represents a hydrogen atom or a substituent; L 41 represents a connecting group; n 41 represents an integer of 2 or more; L 42 represents a di- or more valent connecting group; and n 42 represents an integer of from 0 to 6.
10. The organic electroluminescent device of claim 8 , wherein the formula (2) is represented by the formula (5):
wherein R 52 , R 53 , and R 54 each represents a hydrogen atom or a substituent; L 51 represents a connecting group; n 51 represents an integer of 2 or more; L 52 represents a di- or more valent connecting group; and n 52 represents an integer of from 0 to 6.
11. The organic electroluminescent device of claim 1 , wherein at least one of the hole injection/transport compounds contained in the luminescent layer is represented by the following formula (6)
wherein R 61 , R 62 and R 63 each represent a substituent and n 61 to n 63 each represent an integer of 0 to 5.
12. The organic electroluminescent device of claim 1 , wherein at least one of the hole injection/transport compounds contained in the luminescent layer is represented by the following formula (7)
wherein R 70 to R 79 each represent a hydrogen atom, an alkyl group, an aryl group, or a group that forms a hydrocarbon ring when bonded to each other.
13. The organic electroluminescent device of claim 1 , wherein at least one of the electron injection/transport compounds contained in the luminescent layer is a nitrogen-containing six-membered ring compound.
14. The organic electroluminescent device of claim 13 , wherein the nitrogen-containing six-membered ring compound is represented by the following formula (8), formula (9), formula (10) or general formula (11)
wherein R 81 to R 85 , R 91 to R 94 , R 101 to R 104 and R 111 to R 113 each represents a hydrogen atom or a substituent.
15. The organic electroluminescent device of claim 1 , wherein at least one of the electron injection/transport compounds contained in the luminescent layer is a nitrogen-containing heterocyclic compound, and that at least one of the hole injection/transport compounds is a pyrrole compound.
16. The organic electroluminescent device of claim 1 , wherein at least one of the electron injection/transport compounds contained in the luminescent layer is a nitrogen-containing heterocyclic compound, and that at least one of the hole injection/transport compounds is a triarylamine-based compound.
17. The organic electroluminescent device of claim 1 , wherein at least one of the electron injection/transport compounds contained in the luminescent layer is a nitrogen-containing heterocyclic compound, and that at least one of the hole injection/transport compounds is a hydrocarbon-based aromatic compound.
18. The organic electroluminescent device of claim 1 , wherein at least one of the electron injection/transport compounds contained in the luminescent layer is a hydrocarbon-based aromatic compound, and that at least one of the hole injection/transport compounds is a triarylamine-based compound.
19. The organic electroluminescent device of claim 1 , wherein at least one of the electron injection/transport compounds contained in the luminescent layer is a hydrocarbon-based aromatic compound, and that at least one of the hole injection/transport compounds is a pyrrole compound.
20. The organic electroluminescent device of claim 1 , wherein the luminescent layer has at least one stacked layer structure of an electron injection/transport compound and a hole injection/transport compound.
21. The organic electroluminescent device of claim 1 , wherein a light emission caused by the organic electroluminescent device originates from the green or blue phosphorescent compound.
22. The organic electroluminescent device of claim 1 , wherein the electron injection/transport compound has an electron affinity of from 2.5 eV to 3.3 eV.
23. The organic electroluminescent device of claim 1 , wherein the hole injection/transport compound has an ionization potential of from 5.8 eV to 6.0 eV.
24. The organic electroluminescent device of claim 1 , wherein the phosphorescent compound is an iridium complex or a platinum complex.
25. The organic electroluminescent device of claim 1 , wherein the phosphorescent compound is an orthocarbometalated iridium complex.
26. The organic electroluminescent device of claim 1 , wherein the phosphorescent compound is an orthocarbometalated iridium complex having a difluorophenylpyridine ligand.