Dibenzofuran and dibenzothiophene derivatives and organic light-emitting devices containing them
A compound of formula (I) wherein Z is a group of formula (II) and Core is selected from groups of formula (IIIa) or (IIIb) wherein X is S or O; R 1 is a substituent; n is 0 or a positive integer; Ar 1 independently in each occurrence is an arylene group; R 2 is a substituent; R 3 is a substituent; R 4 is an arylene or heteroarylene group; Y is C or Si; a is 1, 2 or 3; b is 0 or a positive integer; and c is 0 or a positive integer. The compound of formula (I) may be used as a host for a light-emitting dopant in an organic light-emitting device.
1. A compound of formula (I):
Z-Core-Z (I)
wherein:
Z in each occurrence is independently a group of formula (II):
X is S or O;
R 1 independently in each occurrence is a substituent;
n is 0 or a positive integer;
-* is a direct bond to Core; and
Core is of formula (IIIb):
wherein
R 3 is a substituent;
R 4 is an arylene or heteroarylene group that may independently in each occurrence be unsubstituted or substituted with one or more substituents;
Y is C;
and
c is 1.
2. A compound according to claim 1 wherein each R 4 is a phenylene group that may be unsubstituted or substituted with one or more substituents.
3. A compound according to claim 1 wherein each R 3 is an aryl or heteroaryl group which may be unsubstituted or substituted with one or more substituents.
4. A compound according to claim 1 having a HOMO level of at least 5.8 eV from vacuum level as measured by square wave voltammetry.
5. A composition comprising a compound according to claim 1 and at least one light-emitting dopant.
6. A composition according to claim 5 wherein the light-emitting dopant is a phosphorescent dopant.
7. A composition according to claim 5 wherein the light-emitting dopant is a blue light-emitting material.
8. A composition according to claim 5 wherein the light-emitting dopant is a metal complex comprising at least one unsubstituted or substituted phenylimidazole or phenyltriazole ligand.
9. A formulation comprising a compound according to claim 1 and one or more solvents.
10. An organic light-emitting device comprising an anode, a cathode and a light-emitting layer between the anode and the cathode wherein the light-emitting layer comprises a compound according to claim 1 .
11. An organic light-emitting device comprising an anode, a cathode and a light-emitting layer between the anode and the cathode wherein the organic light-emitting layer comprises a composition according to claim 5 .
12. An organic light-emitting device according to claim 10 wherein the device comprises at least one further light-emitting layer.
13. An organic light-emitting device according to claim 10 wherein the device emits white light.
14. A method of forming an organic light-emitting device according to claim 10 comprising the step of forming the light-emitting layer over one of the anode and the cathode and forming the other of the anode and the cathode over the light-emitting layer.
15. A method according to claim 14 wherein the light-emitting layer is formed by depositing a formulation comprising the compound of formula (I) and one or more solvents and evaporating the one or more solvents.
16. A compound of formula (I):
Z-Core-Z (I)
wherein:
Z in each occurrence is independently a group of formula (II):
X is S or O;
R 1 independently in each occurrence is a substituent;
n is 0 or a positive integer;
-* is a direct bond to Core; and
Core is of formula (IIIb):
wherein each R 3 is an aryl or heteroaryl group which may be unsubstituted or substituted with one or more substituents;
R 4 is an arylene or heteroarylene group that may independently in each occurrence be unsubstituted or substituted with one or more substituents;
Y is C; and
c independently in each occurrence is 0 or a positive integer.
17. A composition comprising a compound according to claim 16 and at least one light-emitting dopant.
18. A formulation comprising a compound according to claim 16 and one or more solvents.
19. An organic light-emitting device comprising an anode, a cathode, and a light-emitting layer between the anode and the cathode, wherein the light-emitting layer comprises a compound according to claim 16 .
20. A method of forming an organic light-emitting device according to claim 19 comprising the step of forming the light-emitting layer over one of the anode and the cathode and forming the other of the anode and the cathode over the light-emitting layer.