Organic electroluminescent materials and devices
A compound including a ligand having the formula: is disclosed. In these formulas, each R 1 , R 2 , and R 3 is independently selected from hydrogen, alkyl, and aryl; at least one of R 1 and R 2 is a branched alkyl containing at least 4 carbon atoms, where the branching occurs at a position further than the benzylic position; where R 1 and R 3 are mono-, di-, tri-, tetra-, or no substitutions; and R 2 is mono-, di-, or no substitutions. Heteroleptic iridium complexes including such compounds, and devices including such compounds are also disclosed.
1. An iridium compound having the formula:
wherein n is 1, 2 or 3;
wherein each R 1 , R 2 , and R 3 is independently selected from the group consisting of hydrogen, alkyl, and aryl;
wherein at least one of R 1 and R 2 is a branched alkyl containing at least 4 carbon atoms, and
wherein the branching occurs at a position further than the benzylic position;
wherein R 1 and R 3 are mono-, di-, tri-, tetra-, or no substitutions;
wherein R 2 is mono-, di-, or no substitutions; and
wherein X—Y is an ancillary ligand.
2. The compound of claim 1 , wherein at least one of R 1 and R 2 is an isobutyl group.
3. The compound of claim 1 , wherein X—Y is acac.
4. The compound of claim 1 , having a structure of the formula:
5. The compound of claim 1 , having a structure of the formula:
6. A compound including a ligand having the formula:
wherein each R 1 , R 2 , and R 3 is independently selected from the group consisting of hydrogen, alkyl, and aryl;
wherein at least one of R 1 and R 2 is a branched alkyl containing at least 4 carbon atoms, and
wherein the branching occurs at a position further than the benzylic position;
wherein R 1 and R 3 are mono-, di-, tri-, tetra-, or no substitutions; and
wherein R 2 is mono-, di-, or no substitutions.
7. The compound of claim 6 , wherein the ligand is coordinated to a metal having an atomic number greater than 40.
8. The compound of claim 6 , wherein the metal is Ir.
9. The compound of claim 6 , including a ligand having a structure of the formula:
10. The compound of claim 6 , including a ligand having a structure of the formula:
11. An organic light emitting device comprising:
an anode;
a cathode; and
an emissive organic layer, disposed between the anode and the cathode, wherein the organic layer comprises an iridium compound having the formula:
wherein n is 1, 2 or 3;
wherein each R 1 , R 2 , and R 3 is independently selected from the group consisting of hydrogen, alkyl, and aryl;
wherein at least one of R 1 and R 2 is a branched alkyl containing at least 4 carbon atoms, and
wherein the branching occurs at a position further than the benzylic position;
wherein R 1 and R 3 are mono-, di-, tri-, tetra-, or no substitutions;
wherein R 2 is mono-, di-, or no substitutions; and
wherein X—Y is an ancillary ligand.
12. The device of claim 11 , wherein the organic emissive layer further comprises BAlq or
13. The device of claim 12 , wherein the compound is:
and the organic emissive layer comprises BAlq.
14. The device of claim 12 , wherein the compound is
and the organic emissive layer comprises
15. The device of claim 11 , wherein at least one of R 1 and R 2 is an isobutyl group.
16. The device of claim 11 , wherein X—Y is acac.
17. The device of claim 11 , wherein the compound has a structure of the formula:
18. The device of claim 11 , wherein the compound has a structure of the formula: