Polymerisable compositions and organic light-emitting devices containing them
Compositions of a mixture of a thiol material and a material that contains a reactive unsaturated carbon-carbon bond that can be polymerised to form a charge-transporting or luminescent film are described, as is an organic light-emitting diode (OLED) device comprising at least one such charge-transporting or emissive layer that has been formed by polymerising a thiol material and an ene material. The process for forming such an OLED, including the deposition of a layer of material comprising the polymerisable composition, from solution, exposing said layer to actinic radiation through a mask, and then optionally developing said film to form a photopatterned film, is also disclosed.
1. A composition comprising a mixture of at least one monomer with the formula:
A-(X) n (1)
and at least one monomer with the formula:
B—(Y) m (2)
where monomers of formula (1) are polymerisable with monomers of formula (2), n and m are integers greater than or equal to 2, such that n and m may be the same or different, X is a group containing a terminal thiol, Y is a group containing a reactive unsaturated carbon-carbon bond, each X may be the same or different, each Y may be the same or different, and A and B are molecular fragments such that at least one of A or B is an organic charge-transporting or organic light-emitting fragment, said mixture further comprising at least one of an emissive dopant and a charge transporting dopant.
2. A composition according to claim 1 , wherein n+m>4.
3. A composition according to claim 1 , wherein A, B, X, and Y do not contain any carbonyl groups.
4. A composition according to claim 1 , wherein at least one of A and B is a hole-transporting molecular fragment.
5. A composition according to claim 1 , wherein at least one of A and B is an electron-transporting molecular fragment.
6. A composition according to claim 1 , wherein at least one of A and B is a bipolar-transporting molecular fragment.
7. A composition according to claim 1 , wherein at least one of A and B is a luminescent molecular fragment.
8. A composition according to claim 1 , further comprising an initiator.
9. A composition according to claim 1 , wherein A in the monomer of the formula 1 comprises a group of the formula
wherein Ar is an optionally-substituted aromatic group and each of Ar 1 , Ar 2 , Ar 3 and Ar 4 is, independently, an optionally-substituted aromatic or optionally-substituted heteroaomatic group and Ar 1 and Ar 2 and/or Ar 3 and Ar 4 may, optionally, be linked together to form, with the N atom to which they are attached, a N-containing ring, wherein at least two of Ar 1 , Ar 2 , Ar 3 and Ar 4 are bonded, optionally via a spacer unit, to the group X.
10. A composition according to claim 9 , wherein A in the monomer of the formula 1 comprises at least one group of the formula
11. A composition according to claim 10 , wherein The monomer of the formula I has the formula
12. A composition according to claim 9 , wherein Ar comprises biphenyl.
13. A composition according to claim 1 , wherein B in the monomer of the formula 2 comprises a group of the formula
wherein Ar is an optionally-substituted aromatic group and each of Ar 1 , Ar 2 , Ar 3 and Ar 4 is, independently, an optionally-substituted aromatic or optionally-substituted heteroaromatic group and Ar 1 and Ar 2 and/or Ar 3 and Ar 4 may, optionally, be linked together to form, with the N atom to which they are attached, a N-containing ring, wherein at least two of Ar 1 , Ar 2 , Ar 3 and Ar 4 are bonded, optionally via a spacer unit, to the group Y.
14. A composition according to claim 13 , wherein B in the monomer of the formula 2 comprises at least one group of the formula
15. A composition according to claim 14 , wherein the monomer of the formula 2 has the formula
16. A composition according to claim 13 , wherein Ar comprises biphenyl.
17. A solid film comprising a thermally-induced or radiation-induced polymerisation reaction product of a composition according to claim 1 .
18. An organic light emitting device comprising laminated in sequence a substrate, an electrode, a first optional charge transporting layer, an emissive layer, a second optional charge transporting layer and a counter electrode wherein at least one of the emissive layer, the first optional charge transporting layer or the second optional charge transporting layer is a film according to claim 17 .
19. A process for forming a device as claimed in claim 18 that comprises the steps of:
i) depositing a film of a composition comprising a mixture of at least one monomer with the formula:
A-(X) n (1)
and at least one monomer with the formula:
B—(Y) m (2)
where monomers of formula (1) are polymerisable with monomers of formula (2), n and m are integers greater than or equal to 2, such that n and m may be the same or different, X is a group containing a terminal thiol, Y is a group containing a reactive unsaturated carbon-carbon bond, each X may be the same or different, each Y may be the same or different, and A and B are molecular fragments such that at least one of A or B is an organic charge-transporting or organic light-emitting fragment, said mixture further comprising at least one of an emissive dopant and a charge transporting dopant; and
ii) polymerising said composition.
20. A process according to claim 19 , comprising exposing at least portions of the film of said composition to actinic radiation to polymerise the corresponding portions of the film.
21. A process according to claim 20 , comprising exposing the film to actinic radiation through a mask and then developing the film to remove the unexposed portions of the film.
22. A device as in claim 18 , wherein the light emitting layer contains an emissive dopant.
23. An organic light emitting device comprising laminated in sequence a substrate, an electrode, a first optional charge transporting layer, an emissive layer, a second optional charge transporting layer and a counter electrode wherein the emissive layer is a film according to claim 17 .
24. A process for forming a device as claimed in claim 23 that comprises the steps of:
i) depositing a film of a composition that is capable of emitting light of a first colour said composition comprising a mixture of at least one monomer with the formula:
A-(X) n (1)
and at least one monomer with the formula:
B—(Y) m (2)
where monomers of formula (1) are polymerisable with monomers of formula (2), n and m are integers greater than or equal to 2, such that n and m may be the same or different, X is a group containing a terminal thiol, Y is a group containing a reactive unsaturated carbon-carbon bond, each X may be the same or different, each Y may be the same or different, and A and B are molecular fragments such that at least one of A or B is an organic charge-transporting or organic light-emitting fragment, said mixture further comprising at least one of an emissive dopant and a charge transporting dopant;
ii) exposing portions of said film to actinic radiation through a mask to polymerise the corresponding portions of the film;
iii) removing unexposed portions of said film to leave a pre-determined pattern;
iv) depositing a film of said composition that is capable of emitting light of a second colour; and
v) exposing portions of said second colour film to actinic radiation through a mask to polymerise the corresponding portions of the film.
25. A device as in claim 23 , wherein the light emitting layer contains an emissive dopant.
26. A process for forming a device as claimed in claim 23 that comprises the steps of:
i) depositing a film of a composition comprising a mixture of at least one monomer with the formula:
A-(X) n (1)
and at least one monomer with the formula:
B—(Y) m (2)
where monomers of formula (1) are polymerisable with monomers of formula (2), n and m are integers greater than or equal to 2, such that n and m may be the same or different, X is a group containing a terminal thiol, Y is a group containing a reactive unsaturated carbon-carbon bond, each X may be the same or different, each Y may be the same or different, and A and B are molecular fragments such that at least one of A or B is an organic charge-transporting or organic light-emitting fragment, said mixture further comprising at least one of an emissive dopant and a charge transporting dopant; and
ii) polymerising said composition.
27. A process according to claim 26 , comprising exposing at least portions of the film of said composition to actinic radiation to polymerise the corresponding portions of the film.
28. A process according to claim 27 , comprising exposing the film to actinic radiation through a mask and then developing the film to remove the unexposed portions of the film.
29. A solid film comprising a radiation-induced polymerisation reaction product of a composition according to claim 1 that has a pre-determined pattern.
30. An organic light emitting device comprising laminated in sequence a substrate, an electrode, a first optional charge transporting layer, an emissive layer, a second optional charge transporting layer and a counter electrode wherein at least one of the emissive layer, the first optional charge transporting layer or the second optional charge transporting layer is a film according to claim 29 .
31. A device as in claim 30 , wherein the light emitting layer contains an emissive dopant.
32. An organic light emitting device comprising laminated in sequence a substrate, an electrode, a first optional charge transporting layer, an emissive layer, a second optional charge transporting layer and a counter electrode wherein the emissive layer is a film according to 29 .
33. A device as in claim 32 , wherein the light emitting layer contains an emissive dopant.