Metal-assisted delayed fluorescent materials as co-host materials for fluorescent OLEDs

1. A light emitting device comprising:

a first electrode;

a hole transporting layer in contact with the first electrode;

a second electrode;

an electron transporting layer in contact with the second electrode; and

an emissive layer between the hole transporting layer and the electron transporting layer, the emissive layer comprising a metal-assisted delayed fluorescent (MADF) emitter, a fluorescent emitter, and a host, wherein the MADF emitter harvests electrogenerated excitons and transfers energy to the fluorescent emitter.

2. The light emitting device of claim 1 , wherein the emissive layer is a single layer comprising the host, the MADF emitter, and the fluorescent emitter.

3. The light emitting device of claim 1 , wherein the emissive layer comprises:

n emitter layers comprising the host and the fluorescent emitter; and

m donor layers comprising the host and the MADF emitter,

wherein n and m are integers ≥1.

4. The light emitting device of claim 3 , wherein n and m are equal.

5. The light emitting device of claim 3 , wherein each emitter layer is adjacent to at least one donor layer.

6. The light emitting device of claim 3 , wherein n=m+1, or m=n+1.

7. The light emitting device of claim 1 , wherein the light emitting device is a fluorescent organic light emitting device.

8. The light emitting device of claim 1 , wherein the MADF emitter is a five-membered or six-membered MADF emitter.

9. The light emitting device of claim 6 , wherein the MADF emitter is a compound of structure (a) or (b):

wherein:

M is platinum (II), palladium (II), nickel (II), manganese (II), zinc (II), gold (III), silver (III), copper (III), iridium (I), rhodium (I), or cobalt (I);

A is an accepting group having one of the following structures, which can optionally be substituted:

D is a donor group having one of the following structures, which can optionally be substituted:

C has one of the following structures, which can optionally be substituted:

N has one of the following structures, which can optionally be substituted:

each of a 0 , a 1 , and a 2 is independently present or absent, and if present, is a direct bond or linking group having one of the following structures:

each of b 1 and b 2 is independently present or absent, and if present, comprises a linking group comprising one or more of the following structures:

X is B, C, N, O, Si, P, S, Ge, As, Se, Sn, Sb, or Te;

Y is N, P, P═O, As, As═O, CH, CR, SiH, SiR, GeH, or GeR;

each R is independently hydrogen, deuterium, halogen, hydroxyl, thiol, nitro, cyano, nitrile, isonitrile, sulfinyl, mercapto, sulfo, carboxyl, hydrazino; substituted or unsubstituted: aryl, cycloalkyl, cycloalkenyl, heterocyclyl, heteroaryl, alkyl, alkenyl, alkynyl, amino, monoalkylamino, dialkylamino, monoarylamino, diarylamino, alkoxy, aryloxy, haloalkyl, aralkyl, ester, alkoxycarbonyl, acylamino, alkoxycarbonylamino, aryloxycarbonylamino, sulfonylamino, sulfamoyl, carbamoyl, alkylthio, ureido, phosphoramide, silyl, polymeric, or any conjugate or combination thereof; and

n is an integer that satisfies the valency of Y.

10. The light emitting device of claim 9 , wherein a 2 is absent.

11. The light emitting device of claim 9 , wherein a 2 and b 2 are absent.

12. The light emitting device of claim 9 , wherein X is N.

13. The light emitting device of claim 9 , wherein A is

a 2 is absent, b 2 is absent, and D is

14. The light emitting device of claim 9 , wherein C in structure (a) or (b) is

15. The light emitting device of claim 9 , wherein N in structure (a) or (b) is

or substituted

16. The light emitting device of claim 9 , wherein M is palladium (II).

17. The light emitting device of claim 9 , wherein the MADF emitter is one of the following:

18. The light emitting device of claim 9 , wherein the MADF emitter is a compound of General Formula A:

wherein:

M is Ir, Rh, Mn, Ni, Cu, or Ag;

each R 1 and R 2 is independently hydrogen, halogen, hydroxyl, nitro, thiol, or substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkane, cycloalkane, heterocyclyl, amino, alkoxy, haloalkyl, arylalkane, or arylalkene;

each of Y 1a and Y 1b is independently O, NR 3 , CR 3 R 4 , S, AsR 3 , BR 3 , PR 3 , P(O)R 3 , or SiR 3 R 4 , or a combination thereof, wherein each of R 3 and R 4 is independently hydrogen; halogen, hydroxyl, thiol, or substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkane, cycloalkane, heterocyclyl, amino, alkoxy, haloalkyl, arylalkane, arylalkene, or R 3 and R 4 together form C═O, wherein each of R 3 and R 4 is independently optionally linked to an adjacent ring structure, thereby forming a cyclic structure;

each of Y 2a , Y 2b , Y 2c , and Y 2d is independently N or CR 5 , wherein R 5 is hydrogen, halogen, hydroxyl, thiol, or substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkane, cycloalkane, heterocyclyl, amino, alkoxy, haloalkyl, arylalkane, or arylalkene;

each of Y 3a , Y 3b , Y 3c , Y 3d , Y 4a , Y 4b , Y 4c , and Y 4d is independently N, O, S, NR 6 , or CR 7 , wherein each of R 6 and R 7 is independently hydrogen, halogen, hydroxyl, thiol, or substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkane, cycloalkane, heterocyclyl, amino, alkoxy, haloalkyl, arylalkane, or arylalkene; or Z(R 8 ) 2 , wherein Z is C or Si, and wherein each R 8 is independently hydrogen, halogen, hydroxyl, thiol, or substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkane, cycloalkane, heterocyclyl, amino, alkoxy, haloalkyl, arylalkane, or arylalkene;

each of m and n is independently 1 or 2; and

each

independently represents partial or full unsaturation of the ring with which it is associated.

19. The light emitting device of claim 18 , wherein Y 2b is C; Y 2c , Y 3b and Y 4b are N and M is Ir or Rh.

20. The light emitting device of claim 9 , wherein the MADF emitter is a compound of General Formula B:

wherein:

M is Pt, Pd, or Au;

each of R 1 and R 2 is independently hydrogen, halogen, hydroxyl, nitro, thiol, or substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkane, cycloalkane, heterocyclyl, amino, alkoxy, haloalkyl, arylalkane, or arylalkene;

each of Y 1a and Y 1b is independently O, NR 3 , CR 3 R 4 , S, AsR 3 , BR 3 , PR 3 , P(O)R 3 , or SiR 3 R 4 , or a combination thereof, wherein each of R 3 and R 4 is independently hydrogen, halogen, hydroxyl, thiol, or substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkane, cycloalkane, heterocyclyl, amino, alkoxy, haloalkyl, arylalkane, arylalkene, or R 3 and R 4 together form C═O, wherein each of R 3 and R 4 is independently optionally linked to an adjacent ring structure, thereby forming a cyclic structure;

each of Y 2a , Y 2b , Y 2c , and Y 2d is independently N or CR 5 , wherein R 5 is hydrogen, halogen, hydroxyl, thiol, or substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkane, cycloalkane, heterocyclyl, amino, alkoxy, haloalkyl, arylalkane, or arylalkene;

each of Y 3a , Y 3b , Y 3c , Y 3d , Y 3e , Y 3f , Y 4a , Y 4b , Y 4c , and Y 4d is independently N, O, S, NR 6 , CR 7 , wherein each of R 6 and R 7 is independently hydrogen, halogen, hydroxyl, thiol, or substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkane, cycloalkane, heterocyclyl, amino, alkoxy, haloalkyl, arylalkane, or arylalkene; or Z(R 8 ) 2 , wherein Z is C or Si, and wherein each R 8 is independently hydrogen, halogen, hydroxyl, thiol, or substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkane, cycloalkane, heterocyclyl, amino, alkoxy, haloalkyl, arylalkane, or arylalkene;

m is 1 or 2; and

each

independently represents partial or full unsaturation of the ring with which it is associated.

21. The light emitting device of claim 20 , wherein M is Pt or Pd, Y 2b and Y 2c are C, Y 3b and Y 4b are N, each of Y 1a and Y 1b is independently O, NR 3 , CR 3 R 4 , S, AsR 3 , BR 3 , PR 3 , P(O)R 3 , or SiR 3 R 4 , or a combination thereof, wherein each of R 3 and R 4 is independently hydrogen, halogen, hydroxyl, thiol, or substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkane, cycloalkane, heterocyclyl, amino, alkoxy, haloalkyl, arylalkane, arylalkene, or R 3 and R 4 together form C═O, wherein each of R 3 and R 4 is independently optionally linked to an adjacent ring structure, thereby forming a cyclic structure.

22. The light emitting device of claim 20 , wherein M is Au, Y 2b , Y 2c and Y 4b are C, Y 3b is N, each of Y 1a and Y 1b is independently O, NR 3 , CR 3 R 4 , S, AsR 3 , BR 3 , PR 3 , P(O)R 3 , or SiR 3 R 4 , or a combination thereof, wherein each of R 3 and R 4 is independently hydrogen, halogen, hydroxyl, thiol, or substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkane, cycloalkane, heterocyclyl, amino, alkoxy, haloalkyl, arylalkane, arylalkene, or R 3 and R 4 together form C═O, wherein each of R 3 and R 4 is independently optionally linked to an adjacent ring structure, thereby forming a cyclic structure.

23. The light emitting device of claim 9 , wherein the MADF emitter is a compound of General Formula C:

wherein:

M is Pt, Pd, Au, or Ag;

each of R 1 and R 2 is independently hydrogen, halogen, hydroxyl, nitro, thiol, or substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkane, cycloalkane, heterocyclyl, amino, alkoxy, haloalkyl, arylalkane, or arylalkene;

one of Y 1a and Y 1b is B(R 3 ) 2 and the other of Y 1a and Y 1b is O, NR 3 , CR 3 R 4 , S, AsR 3 , BR 3 , PR 3 , P(O)R 3 , or SiR 3 R 4 , wherein each of R 3 and R 4 is independently hydrogen, halogen, hydroxyl, thiol, or substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkane, cycloalkane, heterocyclyl, amino, alkoxy, haloalkyl, arylalkane, arylalkene, or R 3 and R 4 together form C═O, wherein each of R 3 and R 4 is independently optionally linked to an adjacent ring structure, thereby forming a cyclic structure;

each of Y 2a , Y 2b , Y 2c , and Y 2d is independently N or CR 5 , wherein R 5 is hydrogen, halogen, hydroxyl, thiol, or substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkane, cycloalkane, heterocyclyl, amino, alkoxy, haloalkyl, arylalkane, or arylalkene;

each of Y 3a , Y 3b , Y 3c , Y 3d , Y 4a , Y 4b , Y 4c , and Y 4d is independently N, O, S, NR 6 , CR 7 , wherein each of R 6 and R 7 independently hydrogen, halogen, hydroxyl, thiol, or substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkane, cycloalkane, heterocyclyl, amino, alkoxy, haloalkyl, arylalkane, or arylalkene; or Z(R 8 ) 2 , wherein Z is C or Si, and wherein each R 8 is independently hydrogen, halogen, hydroxyl, thiol, or substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkane, cycloalkane, heterocyclyl, amino, alkoxy, haloalkyl, arylalkane, or arylalkene;

each of m and n is independently 1 or 2; and

each

independently represents partial or full unsaturation of the ring with which it is associated.

24. The light emitting device of claim 9 , wherein the MADF emitter is a compound of General Formula D:

wherein:

M is Ir, Rh, Pt, Os, Zr, Co, or Ru;

each of R 1 and R 2 is independently hydrogen, halogen, hydroxyl, nitro, thiol, or substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkane, cycloalkane, heterocyclyl, amino, alkoxy, haloalkyl, arylalkane, or arylalkene;

each of Y 1a , Y 1b , Y 1c and Y 1d is independently O, NR 3 , CR 3 R 4 , S, AsR 3 , BR 3 , PR 3 , P(O)R 3 , or SiR 3 R 4 , wherein each of R 3 and R 4 is independently hydrogen, halogen, hydroxyl, thiol, or substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkane, cycloalkane, heterocyclyl, amino, alkoxy, haloalkyl, arylalkane, arylalkene, or R 3 and R 4 together form C═O, wherein each of R 3 and R 4 is independently optionally linked to an adjacent ring structure, thereby forming a cyclic structure;

Y 1e , if present, is O, NR 3 , CR 3 R 4 , S, AsR 3 , BR 3 , PR 3 , P(O)R 3 , or SiR 3 R 4 , wherein each of R 3 and R 4 is independently hydrogen, halogen, hydroxyl, thiol, or substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkane, cycloalkane, heterocyclyl, amino, alkoxy, haloalkyl, arylalkane, arylalkene, or R 3 and R 4 together form C═O, wherein each of R 3 and R 4 is independently optionally linked to an adjacent ring structure, thereby forming a cyclic structure;

each of Y 2a , Y 2b , Y 2c , and Y 2d is independently N or CR 5 , wherein R 5 is hydrogen, halogen, hydroxyl, thiol, or substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkane, cycloalkane, heterocyclyl, amino, alkoxy, haloalkyl, arylalkane, or arylalkene;

each of Y 3a , Y 3b , Y 3c , Y 3d , Y 3e , Y 4a , Y 4b , Y 4c , and Y 4d is independently N, O, S, NR 6 , or CR 7 , wherein each of R 6 and R 7 is independently hydrogen, halogen, hydroxyl, thiol, or substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkane, cycloalkane, heterocyclyl, amino, alkoxy, haloalkyl, arylalkane, or arylalkene; or Z(R 8 ) 2 , wherein Z is C or Si, and wherein each R 8 is independently hydrogen, halogen, hydroxyl, thiol, or substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkane, cycloalkane, heterocyclyl, amino, alkoxy, haloalkyl, arylalkane, or arylalkene;

each of Y 5a , Y 5b , Y 5c , Y 5d , Y 6a , Y 6b , Y 6c , and Y 6d is independently N, O, S, NR 5 , or CR 6 ; each of m, n, l, and p is independently 1 or 2; and

each

independently represents partial or full unsaturation of the ring with which it is associated.

25. The light emitting device of claim 9 , wherein the MADF emitter is a compound of General Formula E:

wherein:

M is Pt, Pd, Ir, Rh, Au, Co, Mn, Ni, Ag, or Cu;

each of Y 1a and Y 1b is independently O, NR 3 , CR 3 R 4 , S, AsR 3 , BR 3 , PR 3 , P(O)R 3 , or SiR 3 R 4 , wherein each of R 3 and R 4 is independently hydrogen, halogen, hydroxyl, thiol, or substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkane, cycloalkane, heterocyclyl, amino, alkoxy, haloalkyl, arylalkane, arylalkene, or R 3 and R 4 together form C═O, wherein each of R 3 and R 4 is independently optionally linked to an adjacent ring structure, thereby forming a cyclic structure;

each of Y 2a , Y 2b , Y 2c , Y 2d , Y 2e , Y 2f , Y 2g , and Y 2h is independently N or CR 5 , wherein R 5 is hydrogen, halogen, hydroxyl, thiol, or substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkane, cycloalkane, heterocyclyl, amino, alkoxy, haloalkyl, arylalkane, or arylalkene;

each of Y 3a , Y 3b , Y 3c , Y 3d , Y 3e , Y 4a , Y 4b , Y 4c , Y 4d , and Y 4e is independently N, O, S, NR 6 , or CR 7 , wherein each of R 6 and R 7 independently hydrogen, halogen, hydroxyl, thiol, or substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkane, cycloalkane, heterocyclyl, amino, alkoxy, haloalkyl, arylalkane, or arylalkene; or Z(R 8 ) 2 , wherein Z is C or Si, and wherein each R 8 is independently hydrogen, halogen, hydroxyl, thiol, or substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkane, cycloalkane, heterocyclyl, aminoalkoxy, haloalkyl, arylalkane, or arylalkene;

m is 1 or 2;

n is 1 or 2;

each

independently represents partial or full unsaturation of the ring with which it is associated; and

each of Fl 1 , Fl 2 , Fl 3 and Fl 4 is independently present or absent, with at least one of Fl 1 , Fl 2 , Fl 3 and Fl 4 present, and if present each of Fl 1 , Fl 2 , Fl 3 and Fl 4 is a fluorescent emitter covalently bonded to one of Y 2a , Y 2d , Y 2e , Y 2f , Y 2g , Y 2h , Y 3c , Y 3d , Y 3e Y 4c , Y 4d and Y 4e .

26. The light emitting device of claim 9 , wherein the MADF emitter has an energy of the singlet excited state(s) no more than 0.2 eV greater than the energy of the lowest triplet state, and the MADF emitter emits simultaneously from the lowest triplet state and the singlet excited state(s) at room temperature or elevated temperature.

27. The light emitting device of claim 26 , wherein the MADF emitter harvests electrogenerated singlet and triplet excitons.

28. The light emitting device of claim 25 , wherein each of Fl 1 , Fl 2 , Fl 3 , Fl 4 , if present, has one of the following structures:

1. Aromatic Hydrocarbons and Their Derivatives

2. Arylethylene, Arylacetylene and Their Derivatives

3. Heterocyclic Compounds and Their Derivatives

4. Other fluorescent luminophors

wherein:

each of R 1l , R 2l , R 3l , R 4l , R 5l , R 6l , R 7l and R 8l is independently hydrogen, deuterium, halogen, hydroxyl, thiol, nitro, cyano, nitrile, isonitrile, sulfinyl, mercapto, sulfo, carboxyl, hydrazino; substituted or unsubstituted: aryl, cycloalkyl, cycloalkenyl, heterocyclyl, heteroaryl, alkyl, alkenyl, alkynyl, amino, monoalkylamino, dialkylamino, monoarylamino, diarylamino, alkoxy, aryloxy, haloalkyl, aralkyl, ester, alkoxycarbonyl, acylamino, alkoxycarbonylamino, aryloxycarbonylamino, sulfonylamino, sulfamoyl, carbamoyl, alkylthio, ureido, phosphoramide, silyl, polymeric, or any conjugate or combination thereof; and

each of Y a , Y b , Y c , Y d , Y e , Y f , Y g , Y h , Y i , Y j , Y k , Y l , Y m , Y n , Y o , and Y p is independently C, N or B; and

each of U a , U b and U c is independently CH 2 , CRR, C═O, SiRR, GeH 2 , GeRR 2 , NH, NR, PH, PR, RP═O, AsR, RAs═O, O, S, S═O, SO 2 , Se, Se═O, SeO 2 , BH, BR, RBi═O, BiH, or BiR, wherein each R is independently hydrogen, deuterium, halogen, hydroxyl, thiol, nitro, cyano, nitrile, isonitrile, sulfinyl, mercapto, sulfo, carboxyl, hydrazino; substituted or unsubstituted: aryl, cycloalkyl, cycloalkenyl, heterocyclyl, heteroaryl, alkyl, alkenyl, alkynyl, amino, monoalkylamino, dialkylamino, monoarylamino, diarylamino, alkoxy, aryloxy, haloalkyl, aralkyl, ester, alkoxycarbonyl, acylamino, alkoxycarbonylamino, aryloxycarbonylamino, sulfonylamino, sulfamoyl, carbamoyl, alkylthio, ureido, phosphoramide, silyl, polymeric, or any conjugate or combination thereof.

29. The light emitting device of claim 1 , wherein the fluorescent emitter comprises one of the following compounds:

3. Heterocyclic Compounds and Their Derivatives

4. Other fluorescent luminophors

wherein:

each of R 1l , R 2l , R 3l , R 4l , R 5l , R 6l , R 7l and R 8l is independently hydrogen, deuterium, halogen, hydroxyl, thiol, nitro, cyano, nitrile, isonitrile, sulfinyl, mercapto, sulfo, carboxyl, hydrazino; substituted or unsubstituted: aryl, cycloalkyl, cycloalkenyl, heterocyclyl, heteroaryl, alkyl, alkenyl, alkynyl, amino, monoalkylamino, dialkylamino, monoarylamino, diarylamino, alkoxy, aryloxy, haloalkyl, aralkyl, ester, alkoxycarbonyl, acylamino, alkoxycarbonylamino, aryloxycarbonylamino, sulfonylamino, sulfamoyl, carbamoyl, alkylthio, ureido, phosphoramide, silyl, polymeric, or any conjugate or combination thereof; and

each of Y a , Y b , Y c , Y d , Y e , Y f , Y g , Y h , Y i , Y j , Y k , Y l , Y m , Y n , Y o , and Y p is independently C, N or B; and

each of U a , U b and U c is independently CH 2 , CRR, C═O, SiRR, GeH 2 , GeRR 2 , NH, NR, PH, PR, RP═O, AsR, RAs═O, O, S, S═O, SO 2 , Se, Se═O, SeO 2 , BH, BR, RBi═O, BiH, or BiR, wherein each R is independently hydrogen, deuterium, halogen, hydroxyl, thiol, nitro, cyano, nitrile, isonitrile, sulfinyl, mercapto, sulfo, carboxyl, hydrazino; substituted or unsubstituted: aryl, cycloalkyl, cycloalkenyl, heterocyclyl, heteroaryl, alkyl, alkenyl, alkynyl, amino, monoalkylamino, dialkylamino, monoarylamino, diarylamino, alkoxy, aryloxy, haloalkyl, aralkyl, ester, alkoxycarbonyl, acylamino, alkoxycarbonylamino, aryloxycarbonylamino, sulfonylamino, sulfamoyl, carbamoyl, alkylthio, ureido, phosphoramide, silyl, polymeric, or any conjugate or combination thereof.