FLUORESCENT ORGANIC LIGHT EMITTING ELEMENTS HAVING HIGH EFFICIENCY

Abstract

The present invention relates to organic light emitting elements, comprising thermally activated delayed fluorescence (TADF) emitters and/or hosts on basis of benzotriazoles, which have a sufficiently small energy gap between S.sub.1 and T.sub.1 (?E.sub.ST) to enable up-conversion of the triplet exciton from T.sub.1 to S.sub.1. The organic light emitting elements show high electroluminescent efficiency.

Claims

1.-22. (canceled)

23. An organic light-emitting element, comprising a light-emitting layer comprising i) a compound of formula ##STR00180## as guest and a host material; or ii) a compound of formula ##STR00181## as host and a fluorescent guest material, wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are independently of each other H, D, F, Cl, a C.sub.1-C.sub.25alkyl group, a C.sub.1-C.sub.25alkoxy group, a C.sub.6-C.sub.10aryloxy group, or a donor group of formula ##STR00182## R.sup.5, R.sup.6, R.sup.7, R.sup.8 and R.sup.9 are independently of each other H, D, F, Cl, a C.sub.1-C.sub.25alkyl group, a C.sub.1-C.sub.25alkoxy group, a C.sub.6-C.sub.10aryloxy group, a group of formula ##STR00183## (Xa), (Xb), (Xc), or (Xd); R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are independently of each other H, D, F, Cl, a C.sub.1-C.sub.25alkyl group, a C.sub.1-C.sub.25alkoxy group, or a C.sub.6-C.sub.10aryloxy group; or R.sup.1 and R.sup.2 together form a group of formula ##STR00184## R.sup.1 and R.sup.2 together form a group of formula ##STR00185## R.sup.3 and R.sup.4 together form a group of formula ##STR00186## R.sup.3 and R.sup.4 together form a group of formula ##STR00187## R.sup.5 and R.sup.6 together form a group of formula ##STR00188## and/or R.sup.8 and R.sup.9 together form a group of formula ##STR00189## A.sup.1, A.sup.2, A.sup.3, A.sup.4, A.sup.5, A.sup.6, A.sup.7 and A.sup.8 are independently of each other H, D, F, Cl, a C.sub.1-C.sub.25alkyl group, or a donor group of formula (Xa), (Xb), (Xc), or (Xd); A.sup.9, A.sup.10, A.sup.11, A.sup.12, A.sup.13, A.sup.14, A.sup.15 and A.sup.16 are independently of each other H, D, F, Cl, a C.sub.1-C.sub.25alkyl group, or a donor group of formula (Xa), (Xb), (Xc), or (Xd); X.sup.1 and X.sup.2 are independently of each other a single bond, O, S, N(R.sup.15), C(?O), C(R.sup.16)(R.sup.17), B(R.sup.18), or Si(R.sup.19)(R.sup.20) and R.sup.10, R.sup.11, R.sup.12, R.sup.13, R.sup.21 and R.sup.21 are independently of each other H, D, F, Cl, or a C.sub.1-C.sub.25alkyl group; R.sup.14, R.sup.15, R.sup.16, R.sup.17, R.sup.18, R.sup.19 and R.sup.20 are independently of each other H, D, a C.sub.1-C.sub.25alkyl group, or a C.sub.6-C.sub.14aryl group, which can optionally be substituted by one, or more groups selected from a C.sub.1-C.sub.25alkyl group, a C.sub.1-C.sub.25alkoxy group and a C.sub.6-C.sub.10aryloxy group; with the proviso that at least one donor group of formula (Xc) is present in the compound of formula (I); characterized in that it emits delayed fluorescence.

24. The organic light-emitting element according to claim 23, wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.6, R.sup.7, R.sup.8 and R.sup.9 are independently of each other H, a C.sub.1-C.sub.25alkyl group, a C.sub.1-C.sub.25alkoxy group, a C.sub.6-C.sub.10aryloxy group, a donor group of formula ##STR00190## or R.sup.1 and R.sup.2 together form a group of formula ##STR00191## and/or R.sup.8 and R.sup.9 together form a group of formula ##STR00192## R.sup.5 is H, a C.sub.1-C.sub.25alkyl group, a group of formula ##STR00193## or a donor group of formula (Xa), (Xb), (Xc), or (Xd); X.sup.1 and X.sup.2 are independently of each other a single bond, O, S, C(O), N(R.sup.15), or C(R.sup.16)(R.sup.17); and R.sup.10, R.sup.11, R.sup.12, R.sup.13, R.sup.21 and R.sup.21 are independently of each other H, or a C.sub.1-C.sub.25alkyl group; R.sup.14 and R.sup.15 are independently of each other a group of formula ##STR00194## R.sup.16 and R.sup.17 are independently of each other H, a C.sub.1-C.sub.25alkyl group; R.sup.22 and R.sup.23 are independently of each other H, a C.sub.1-C.sub.25alkyl group, a C.sub.1-C.sub.25alkoxy group, or a C.sub.6-C.sub.10aryloxy group; with the proviso that at least one of R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8 and R.sup.9 is a donor group of formula (Xc).

25. The organic light-emitting element according to claim 23, wherein the compound of formula (I) is a compound of formula ##STR00195## wherein R.sup.1 and R.sup.2 are independently of each other H, or a C.sub.1-C.sub.25alkyl group, or R.sup.1 and R.sup.2 together form a group of formula ##STR00196## R.sup.3, R.sup.7 and R.sup.8 are independently of each other H, a C.sub.1-C.sub.25alkyl group, or a donor group of formula ##STR00197## R.sup.5 is H, a C.sub.1-C.sub.25alkyl group, a group of formula ##STR00198## or a donor group of formula (Xa), (Xb), (Xc), or (Xd); R.sup.9 is H, or R.sup.8 and R.sup.9 together form a group of formula ##STR00199## X.sup.1 and X.sup.2 are independently of each other a single bond, O, S, N(R.sup.15), or C(R.sup.16)(R.sup.17); R.sup.10, R.sup.12, R.sup.13, R.sup.21 and R.sup.21 are independently of each other H, or a C.sub.1-C.sub.25alkyl group; R.sup.14 and R.sup.15 are independently of each other a group of formula ##STR00200## R.sup.16 and R.sup.17 are independently of each other H, a C.sub.1-C.sub.25alkyl group; R.sup.22 and R.sup.23 are independently of each other H, or a C.sub.1-C.sub.25alkyl group; with the proviso that at least one of R.sup.3, R.sup.5 and R.sup.7 is a donor group of formula (Xc).

26. The organic light-emitting element according to claim 23, wherein the compound of formula (I) is a compound of formula ##STR00201## wherein R.sup.1 and R.sup.2 are independently of each other H, or a C.sub.1-C.sub.25alkyl group, or R.sup.1 and R.sup.2 together form a group of formula ##STR00202## R.sup.3 is H, a C.sub.1-C.sub.25alkyl group, or a donor group of formula ##STR00203## R.sup.7 is H, a C.sub.1-C.sub.25alkyl group, or a donor group of formula (Xa), (Xb), (Xc), or (Xd); R.sup.8 and R.sup.9 are H, or R.sup.8 and R.sup.9 together form a group of formula ##STR00204## X.sup.1 and X.sup.2 are independently of each other a single bond, O, S, N(R.sup.15), or C(R.sup.16)(R.sup.17); R.sup.10, R.sup.11, R.sup.12, R.sup.13, R.sup.21 and R.sup.21 are independently of each other H, or a C.sub.1-C.sub.25alkyl group; R.sup.14 and R.sup.15 are independently of each other a group of formula ##STR00205## R.sup.16 and R.sup.17 are independently of each other H, a C.sub.1-C.sub.25alkyl group; R.sup.22 and R.sup.23 are independently of each other H, or a C.sub.1-C.sub.25alkyl group; with the proviso that at least one of R.sup.3 and R.sup.7 is a donor group of formula (Xc).

27. The organic light-emitting element according to claim 23, wherein the compound of formula (I) is a compound of formula ##STR00206## wherein R.sup.3 and R.sup.5 are H and R.sup.7 is a donor group of formula ##STR00207## R.sup.3 and R.sup.5 are H and R.sup.7 is a donor group of formula (Xc); or R.sup.3 is a donor group of formula (Xc) and R.sup.5 and R.sup.7 are H; or R.sup.5 is a donor group of formula (Xc) and R.sup.3 and R.sup.7 are H; or R.sup.3 and R.sup.7 are a donor group of formula (Xc) and R.sup.5 is H; or ##STR00208## wherein R.sup.3 and R.sup.5 are H and R.sup.7 is a donor group of formula (Xc); or R.sup.3 is a donor group of formula (Xc) and R.sup.5 and R.sup.7 are H; or R.sup.5 is a donor group of formula (Xc) and R.sup.3 and R.sup.7 are H; or R.sup.3 and R.sup.7 are a donor group of formula (Xc) and R.sup.5 is H; and R.sup.8 and R.sup.9 are H, or R.sup.8 and R.sup.9 together form a group of formula ##STR00209## R.sup.13 are independently of each other H, or a C.sub.1-C.sub.25alkyl group; R.sup.14 is a group of formula ##STR00210## and R.sup.22 and R.sup.23 are independently of each other H, or a C.sub.1-C.sub.25alkyl group.

28. The organic light-emitting element according to claim 27, wherein the compound of formula (I) is a compound of formula (Ia), wherein R.sup.5, R.sup.8 and R.sup.9 are H; R.sup.3 is H and R.sup.7 is a donor group of formula ##STR00211## or R.sup.3 is a donor group of formula (Xc) and R.sup.7 is H; or R.sup.3 and R.sup.7 are a donor group of formula (Xc); or a compound of formula (Ia), wherein R.sup.5 is H; R.sup.8 and R.sup.9 together form a group of formula ##STR00212## R.sup.3 is H and R.sup.7 is a donor group of formula (Xc); or R.sup.3 is a donor group of formula (Xc) and R.sup.7 is H; or R.sup.3 and R.sup.7 are a donor group of formula (Xc); or a compound of formula (Ia), wherein R.sup.3, R.sup.7, R.sup.8 and R.sup.9 are H; R.sup.5 is a donor group of formula (Xc); or a compound of formula (Ia), wherein R.sup.5, R.sup.8 and R.sup.9 are H; R.sup.3 is H and R.sup.7 is a donor group of formula (Xc); or R.sup.3 is a donor group of formula (Xc) and R.sup.7 is H; or R.sup.3 and R.sup.7 are a donor group of formula (Xc); or a compound of formula (Ia), wherein R.sup.5 is H; R.sup.8 and R.sup.9 together form a group of formula ##STR00213## R.sup.3 is H and R.sup.7 is a donor group of formula (Xc); or R.sup.3 is a donor group of formula (Xc) and R.sup.7 is H; or R.sup.3 and R.sup.7 are a donor group of formula formula (Xc); or a compound of formula (Ia), wherein R.sup.3, R.sup.7, R.sup.8 and R.sup.9 are H; R.sup.5 is a donor group of formula (Xc); R.sup.13 are independently of each other H, or a C.sub.1-C.sub.25alkyl group; R.sup.14 is a group of formula ##STR00214## and R.sup.22 and R.sup.23 are independently of each other H, or a C.sub.1-C.sub.25alkyl group.

29. The organic light-emitting element according to claim 25, wherein the compound of formula (I) is a compound of formula ##STR00215## wherein R.sup.5 is a group of formula ##STR00216## R.sup.7 and R.sup.8 are a donor group of formula ##STR00217## or a compound of formula (Ib), wherein R.sup.5 is a donor group of formula (Xc), and R.sup.7 and R.sup.8 are independently of each other H, or a C.sub.1-C.sub.25alkyl group; R.sup.13 are independently of each other H, or a C.sub.1-C.sub.25alkyl group; R.sup.14 is a group of formula ##STR00218## and R.sup.22 and R.sup.23 are independently of each other H, or a C.sub.1-C.sub.25alkyl group.

30. The organic light-emitting element according to claim 23, wherein the compound of formula (I) is a compound of formula ##STR00219## wherein R.sup.1 and R.sup.4 are a donor group of formula ##STR00220## R.sup.8 and R.sup.9 are H, or R.sup.8 and R.sup.9 together form a group of formula ##STR00221## R.sup.13 are independently of each other H, or a C.sub.1-C.sub.25alkyl group; R.sup.14 is a group of formula ##STR00222## and R.sup.22 and R.sup.23 are independently of each other H, or a C.sub.1-C.sub.25alkyl group.

31. The organic light-emitting element according to claim 23, wherein the donor group is a donor group of formula (Xc), wherein R.sup.13 is a group of formula ##STR00223## and R.sup.14 is a group of formula ##STR00224##

32. The organic light-emitting element according to claim 23, wherein the donor group is a group of formula ##STR00225##

33. A compound of formula ##STR00226## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are independently of each other H, D, F, Cl, a C.sub.1-C.sub.25alkyl group, a C.sub.1-C.sub.25alkoxy group, a C.sub.6-C.sub.10aryloxy group, or a donor group of formula ##STR00227## R.sup.5, R.sup.6, R.sup.7, R.sup.8 and R.sup.9 are independently of each other H, D, F, Cl, a C.sub.1-C.sub.25alkyl group, a C.sub.1-C.sub.25alkoxy group, a C.sub.6-C.sub.10aryloxy group, a group of formula ##STR00228## (Xa), (Xb), (Xc), or (Xd); R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are independently of each other H, D, F, Cl, a C.sub.1-C.sub.25alkyl group, a C.sub.1-C.sub.25alkoxy group, or a C.sub.6-C.sub.10aryloxy group, or; R.sup.1 and R.sup.2 together form a group of formula ##STR00229## R.sup.1 and R.sup.2 together form a group of formula ##STR00230## R.sup.3 and R.sup.4 together form a group of formula ##STR00231## R.sup.3 and R.sup.4 together form a group of formula ##STR00232## R.sup.5 and R.sup.6 together form a group of formula ##STR00233## and/or R.sup.8 and R.sup.9 together form a group of formula ##STR00234## A.sup.1, A.sup.2, A.sup.3, A.sup.4, A.sup.5, A.sup.6, A.sup.7 and A.sup.8 are independently of each other H, D, F, Cl, a C.sub.1-C.sub.25alkyl group, or a donor group of formula (Xa), (Xb), (Xc), or (Xd); A.sup.9, A.sup.10, A.sup.11, A.sup.12, A.sup.13, A.sup.14, A.sup.15 and A.sup.16 are independently of each other H, D, F, Cl, a C.sub.1-C.sub.25alkyl group, or a donor group of formula (Xa), (Xb), (Xc), or (Xd); X.sup.1 and X.sup.2 are independently of each other O, S, N(R.sup.15), C(R.sup.16)(R.sup.17), B(R.sup.18), or Si(R.sup.19)(R.sup.20) and R.sup.10, R.sup.11, R.sup.12, R.sup.13, R.sup.21 and R.sup.21 are independently of each other H, D, F, Cl, or a C.sub.1-C.sub.25alkyl group; R.sup.14, R.sup.15, R.sup.16, R.sup.17, R.sup.18, R.sup.19 and R.sup.20 are independently of each other H, D, a C.sub.1-C.sub.25alkyl group, or a C.sub.6-C.sub.14aryl group, which can optionally be substituted by one, or more groups selected from a C.sub.1-C.sub.25alkyl group, a C.sub.1-C.sub.25alkoxy group and a C.sub.6-C.sub.10aryloxy group; with the proviso that at least one donor group of formula (Xc) is present in the compound of formula (I).

34. The compound according to claim 33, wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.6, R.sup.7, R.sup.8 and R.sup.9 are independently of each other H, a C.sub.1-C.sub.25alkyl group, a C.sub.1-C.sub.25alkoxy group, a C.sub.6-C.sub.10aryloxy group, a donor group of formula ##STR00235## or R.sup.1 and R.sup.2 together form a group of formula ##STR00236## and/or R.sup.8 and R.sup.9 together form a group of formula ##STR00237## R.sup.5 is H, a C.sub.1-C.sub.25alkyl group, a group of formula ##STR00238## or a donor group of formula (Xa), (Xb), (Xc), or (Xd); X.sup.1 and X.sup.2 are independently of each other O, S, N(R.sup.15), or C(R.sup.16)(R.sup.17); and R.sup.10, R.sup.11, R.sup.12, R.sup.21 and R.sup.21 are independently of each other H, or a C.sub.1-C.sub.25alkyl group; R.sup.15 is a group of formula ##STR00239## R.sup.16 and R.sup.17 are independently of each other H, a C.sub.1-C.sub.25alkyl group; R.sup.22 and R.sup.23 are independently of each other H, a C.sub.1-C.sub.25alkyl group, a C.sub.1-C.sub.25alkoxy group, or a C.sub.6-C.sub.10aryloxy group; with the proviso that at least one of R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8 and R.sup.9 is a donor group of formula (Xc).

35. The compound according to claim 33, wherein the compound of formula (I) is a compound of formula ##STR00240## wherein R.sup.1 and R.sup.2 are independently of each other H, or a C.sub.1-C.sub.25alkyl group, or R.sup.1 and R.sup.2 together form a group of formula ##STR00241## R.sup.3, R.sup.7 and R.sup.8 are independently of each other H, a C.sub.1-C.sub.25alkyl group, or a donor group of formula ##STR00242## R.sup.5 is H, a C.sub.1-C.sub.25alkyl group, a group of formula ##STR00243## or a donor group of formula (Xa), (Xb), (Xc), or (Xd); R.sup.9 is H, or R.sup.8 and R.sup.9 together form a group of formula ##STR00244## X.sup.1 and X.sup.2 are independently of each other O, S, N(R.sup.15), or C(R.sup.16)(R.sup.17); R.sup.10, R.sup.11, R.sup.12, R.sup.13, R.sup.21 and R.sup.21 are independently of each other H, or a C.sub.1-C.sub.25alkyl group; R.sup.14 and R.sup.15 are independently of each other a group of formula ##STR00245## R.sup.16 and R.sup.17 are independently of each other H, a C.sub.1-C.sub.25alkyl group; R.sup.22 and R.sup.23 are independently of each other H, or a C.sub.1-C.sub.25alkyl group; with the proviso that at least one of R.sup.3, R.sup.5 and R.sup.7 is a donor group of formula (Xc).

36. The compound according to claim 35, which is a compound of formula ##STR00246## wherein R.sup.1 and R.sup.2 are independently of each other H, or a C.sub.1-C.sub.25alkyl group, or R.sup.1 and R.sup.2 together form a group of formula ##STR00247## R.sup.3 is H, a C.sub.1-C.sub.25alkyl group, or a donor group of formula ##STR00248## R.sup.7 is H, a C.sub.1-C.sub.25alkyl group, or a donor group of formula (Xa), (Xb), (Xc), or (Xd); R.sup.8 and R.sup.9 are H, or R.sup.8 and R.sup.9 together form a group of formula ##STR00249## X.sup.1 and X.sup.2 are independently of each other O, S, N(R.sup.15), or C(R.sup.16)(R.sup.17); R.sup.10, R.sup.11, R.sup.12, R.sup.13, R.sup.21 and R.sup.21 are independently of each other H, or a C.sub.1-C.sub.25alkyl group; R.sup.14 and R.sup.15 are independently of each other a group of formula ##STR00250## R.sup.16 and R.sup.17 are independently of each other H, a C.sub.1-C.sub.25alkyl group; R.sup.22 and R.sup.23 are independently of each other H, or a C.sub.1-C.sub.25alkyl group; with the proviso that at least one of R.sup.3 and R.sup.7 is a donor group of formula (Xc).

37. The compound according to claim 35, which is a compound of formula ##STR00251## wherein R.sup.3 and R.sup.5 are H and R.sup.7 is a donor group of formula ##STR00252## or R.sup.3 is a donor group of formula (Xc) and R.sup.5 and R.sup.7 are H; or R.sup.5 is a donor group of formula (Xc) and R.sup.3 and R.sup.7 are H; or R.sup.3 and R.sup.7 are a donor group of formula (Xc) and R.sup.5 is H; or ##STR00253## wherein R.sup.3 and R.sup.5 are H and R.sup.7 is a donor group of formula (Xc); or R.sup.3 is a donor group of formula (Xc) and R.sup.5 and R.sup.7 are H; or R.sup.5 is a donor group of formula (Xc) and R.sup.3 and R.sup.7 are H; or R.sup.3 and R.sup.7 are a donor group of formula (Xc) and R.sup.5 is H; R.sup.8 and R.sup.9 are H, or R.sup.8 and R.sup.9 together form a group of formula ##STR00254## R.sup.13 are independently of each other H, or a C.sub.1-C.sub.25alkyl group; R.sup.14 is a group of formula ##STR00255## and R.sup.22 and R.sup.23 are independently of each other H, or a C.sub.1-C.sub.25alkyl group.

38. The compound according to claim 37, wherein the compound of formula (I) is a compound of formula (Ia), wherein R.sup.5, R.sup.8 and R.sup.9 are H; R.sup.3 is H and R.sup.7 is a donor group of formula ##STR00256## or R.sup.3 is a donor group of formula (Xc) and R.sup.7 is H; or R.sup.3 and R.sup.7 are a donor group of formula (Xc); or a compound of formula (Ia), wherein R.sup.5, R.sup.8 and R.sup.9 are H; R.sup.3 is H and R.sup.7 is a donor group of formula (Xc); or R.sup.3 is a donor group of formula (Xc) and R.sup.7 is H; or R.sup.3 and R.sup.7 are a donor group of formula formula (Xc); R.sup.13 are independently of each other H, or a C.sub.1-C.sub.25alkyl group; R.sup.14 is a group of formula ##STR00257## and R.sup.22 and R.sup.23 are independently of each other H, or a C.sub.1-C.sub.25alkyl group.

39. The compound according to claim 35, wherein the compound of formula (I) is a compound of formula ##STR00258## wherein R.sup.5 is a group of formula ##STR00259## R.sup.7 and R.sup.8 are a donor group of formula ##STR00260## or a compound of formula (Ib), wherein R.sup.5 is a donor group of formula (Xc), and R.sup.7 and R.sup.8 are independently of each other H, or a C.sub.1-C.sub.25alkyl group; R.sup.13 are independently of each other H, or a C.sub.1-C.sub.25alkyl group; R.sup.14 is a group of formula ##STR00261## and R.sup.22 and R.sup.23 are independently of each other H, or a C.sub.1-C.sub.25alkyl group.

40. The compound according to claim 33, wherein the compound of formula (I) is a compound of formula ##STR00262## wherein R.sup.1 and R.sup.4 are a donor group of formula ##STR00263## R.sup.8 and R.sup.9 are H, or R.sup.8 and R.sup.9 together form a group of formula ##STR00264## R.sup.13 are independently of each other H, or a C.sub.1-C.sub.25alkyl group; R.sup.14 is a group of formula ##STR00265## and R.sup.22 and R.sup.23 are independently of each other H, or a C.sub.1-C.sub.25alkyl group.

41. The compound according to claim 33, wherein the donor group is a donor group of formula (Xc), wherein R.sup.13 is a group of formula ##STR00266## and R.sup.14 is a group of formula ##STR00267##

42. The compound according to claim 33, wherein the donor group is a group of formula ##STR00268##

43. A light-emitting layer comprising the compound according to claim 33.

44. An organic light emitting element, comprising the compound according to claim 33.

Description

EXAMPLES

Example 1

[0101] ##STR00165##

[0102] a) Phenyl hydrazine HCl (0.39 mol) and NaOAc.3H.sub.2O (0.59 mol) are placed in a 1.5 l flask with EtOH 550 ml. While stirring, 1-fluoro-4-bromo-2-nitrobenzene (0.20 mol) is added (by pouring). The slurry becomes slightly orange. The mixture is heated to reflux overnight (20 hours). After cooling to room temperature, the mixture is filtered and washed with EtOH. Without vacuum on the frit, water is added with stirring to dissolve the NaCl and NaF. Vacuum is applied and the process is repeated. Stirring twice with MeOH in the same manner and applying vacuum give a light orange solid. Volatiles are removed in vacuum. (Yield: 38.2%)

##STR00166##

[0103] b) The product from example 1a (0.11 mol), and sodium hydrogen sulfite (0.11 mol) are placed in a 250 ml 3 neck round balloon with 200 ml dimethyl formamide (DMF). While stirring, the reaction mixture is heated to 110? C. overnight. After cooling to room temperature, the mixture is poured into 300 ml ice water, and then the precipitate is filtered off and washed with 1000 ml water and 500 ml EtOH. Volatiles are removed in vacuum give a slightly beige powder (yield: 35.5%). .sup.1H-NMR (ppm, CDCl.sub.3): 8.15 (dd, 2H), 8.03 (d, 1H), 7.57-7.50 (m, 5H).

##STR00167##

[0104] c) The product from example 1b (1.45 mmol), phenoxazine (1.75 mmol), palladium acetate (0.03 mmol), tri-tert-Buthylphosphine (0.06 mmol), sodium t-buthoxide (2.9 mmol) and 10 ml of toluene are placed in a 50 ml flask. The mixture is stirred at 110? C. overnight and cooled. The mixture is then poured into H.sub.2O and extracted with ethylacetate. The organic layer is dried over MgSO.sub.4 and concentrated by evaporation. Column chromatography of the crude product with dichloromethane/hexane (1:15-1:5) as eluent gives a yellow solid (yield: 81.9%). The product is subsequently purified using zone sublimation. 1H-NMR (ppm, CDCl.sub.3): 8.33 (td, 3H), 8.24 (d, 1H), 7.69 (td, 2H), 7.60 (td, 1H), 7.45 (dd, 1H), 6.76 (dd, 2H), 6.72-6.61 (m, 4H), 5.97 (dd, 2H).

Example 2

[0105] ##STR00168##

[0106] a) 4-Bromoaniline (58.14 mmol) is dissolved in 200 ml water using 174 mmol HCl. The mixture is cooled to 0? C. and sodium nitrite (58.1 mmol) in 30 ml water is added dropwise over 30 minutes. After 45 minutes the diazonium salt is added via cannula to a mixture of 1-amino-4-bromonaphthalene (58.14 mmol) in 300 ml ethanol at 0? C. After 2 hours sodium carbonate (80.2 mmol) in 100 ml water is added dropwise, producing a pH of 7. After an additional 30 minutes the red precipitate is filtered and washed with water (2?300 ml). The brown-red solid is triturated in 100 ml methanol overnight, filtered and dried. The product is dried in vacuo to give a bright red solid (yield: 91.0%). .sup.1H-NMR (ppm, (CD.sub.3).sub.2SO): 8.59 (d, 1H), 8.12 (s, 1H), 8.07 (d, 1H), 8.04 (d, 2H), 7.82 (d, 1H), 7.76 (d, 2H), 7.70 (t, 1H).

##STR00169##

[0107] b) The product from step 2a (49.37 mmol) and copper(II) acetate (0.49 mmol) are placed in a 250 ml flask with a stir bar. 250 ml tert-amyl alcohol is added and the mixture is heated to 80? C. tert-Butyl hydroperoxide, (98.7 mmol) is slowly added and the reaction is monitored by TLC. The flask is cooled to room temperature and the product is filtered. Washing with tert-amyl alcohol and removal of volatiles in vacuo give a light brown solid. The product is triturated in 30 ml methanol overnight, filtered and dried to give an off-white solid (yield: 77.0%). .sup.1H-NMR (ppm, CDCl.sub.3): 8.47 (m, 1H), 8.20 (d, 1H), 8.08 (d, 2H), 8.01 (s, 1H), 7.58 (m, 2H), 7.49 (d, 2H).

##STR00170##

[0108] c) The product from example 2b (2.40 mmol), phenoxazine (6.2 mmol), palladium acetate (0.01 mmol), tri-tert-butylphosphine (0.02 mmol), sodium t-buthoxide (7.2 mmol) and 30 ml of toluene are placed in a 100 ml flask. The mixture is stirred at 110? C. overnight and cooled. The mixture is then poured into H.sub.2O and extracted with ethylacetate. The organic layer is dried over MgSO.sub.4 and concentrated by evaporation. Column chromatography of the crude product with ethylacetate/hexane (1:5) as eluent, followed by reprecipitation from dichloromethane-hexane gives a yellow solid (yield: 53.0%). The product is subsequently purified using zone sublimation. .sup.1H-NMR (ppm, CDCl.sub.3): 8.73 (d, 1H), 8.61 (d, 2H), 8.35 (s, 1H), 8.06 (d, 1H), 7.75 (m, 3H), 6.82-6.65 (m, 11H), 6.57 (td, 2H), 6.03 (m, 2H), 5.90 (dd, 2H).

Example 3

[0109] ##STR00171##

[0110] 4-Bromophenyl hydrazine-HCl (0.39 mol), and NaOAc.3H20 (0.59 mol) are placed in a 1.5 l flask with EtOH 550 ml. While stirring, 1-fluoro-4-bromo-2-nitrobenzene (0.20 mol) is added (by pouring). The slurry becomes slightly orange. The mixture is heated to reflux overnight (20 hours). After cooling to room temperature, the mixture is filtered and washed with EtOH. Without vacuum on the frit, water is added with stirring to dissolve the NaCl and NaF. Vacuum is applied and the process is repeated. Stirring twice with MeOH in the same manner and applying vacuum give a light yellow, crystalline solid. Volatiles are removed in vacuum (yield: 93.4%).

##STR00172##

[0111] b) The product from example 3a (0.11 mol), and sodium hydrogen sulfite (0.11 mol) are placed in a 250 ml 3 neck round balloon with 200 ml DMF. While stirring, the reaction mixture is heated to 110? C. overnight. After cooling to room temperature, the mixture is poured into 300 ml ice water, and then the precipitate is filtered off and washed with 1000 ml water and 500 ml EtOH. Volatiles are removed in vacuum give a slightly beige powder (yield: 93.4%). .sup.1H-NMR (ppm, CDCl.sub.3): 8.21 (dd, 2H), 8.09 (d, 1H), 7.79 (dd, 1H), 7.67 (dd, 2H), 7.49 (dd, 1H).

##STR00173##

[0112] c) The product from example 3b (0.62 mmol), phenoxazine (1.55 mmol), palladium acetate (0.01 mmol), tri-tert-butylphosphine (0.02 mmol), sodium t-buthoxide (1.87 mmol) and 10 ml of toluene are placed in a 50 ml flask. The mixture is stirred at 110? C. overnight and cooled. The mixture is then poured into H.sub.2O and extracted with ethylacetate. The organic layer is dried over MgSO.sub.4 and concentrated by evaporation. Column chromatography of the crude product with dichloromethane/hexane (1:10) as eluent gives a yellow solid (yield: 30.6%). The product is subsequently purified using zone sublimation. .sup.1H-NMR (ppm, CDCl3): 8.60 (d, 2H), 8.35 (d, 1H), 8.29 (d, 1H), 7.75 (d, 2H), 7.49 (dd, 1H), 6.80-6.63 (m, 12H), 6.00 (dd, 4H)

Application Example 1

a) Photoluminescent Characterization in Neat Film

[0113] On a silicon substrate, compound

##STR00174##

is vacuum-deposited in a thickness of 50 nm. Absorption, fluorescent spectra (excitation at 339 nm) and photoelectron yield spectroscopy of the film are measured, subsequently HOMO and LUMO (eV) of the compound are estimated as 5.76 eV and 3.20 eV, respectively.

b) Photoluminescent Characterization in Host-Guest Film

[0114] On a silicon substrate, mCBP doped with 8.6% by weight of compound (A-5) is co-deposited in a thickness of 100 nm. The time-resolved and temperature-dependent emission spectra of the host-guest film are measured by photoluminescence spectroscopy with a streak camera. The prompt (?30 ns) and delayed (>1 ?s) fluorescent components and the temperature dependency are observed as shown in FIG. 1 and Table 1. The host-guest film shows an emission peak at 520 nm in PL spectrum (see FIG. 2).

TABLE-US-00001 TABLE 1 Temperature dependency of PL emission of codeposited film (mCBP doped with 8.6% by weight of compound (A-5)) (streak camera) Temperature (K) Prompt PL intensity (a.u.) Delayed PL intensity (a.u.) 8 0.997 0.295 68 0.914 0.361 139 0.923 0.580 199 0.844 0.770 249 0.973 0.970 279 1 0.999 198 0.975 1

[0115] These results indicate that compound (A-5) is a TADF material.

Application Example 2

[0116] An organic light emitting device (OLED) is fabricated by vacuum deposition of ITO (100 nm)/dipyrazino[2,3-f:2,3-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HAT-CN) (10 nm)/

##STR00175##

(Tris-PCz, 30 nm)/88.7% by weight 3,3-di(9H-carbazol-9-yl)biphenyl (mCBP):11.3% by weight compound A-5 (30 nm)/2,4,6-tris(biphenyl-3-yl)-1,3,5-triazine (T2T, 10 nm)/

##STR00176##

(Bpy-TP2, 40 nm)/LiF (0.8 nm)/Al (100 nm) on a glass substrate, subsequently the device is encapsulated and the performance of the device is evaluated. The device shows an emission peak at 534 nm in electroluminescence (EL) spectrum (see FIG. 2) with an external quantum efficiency (EQE) of 11.1% which is higher than the theoretical value of conventional fluorescent materials (EQE=5-7.5%).

Application Example 3

[0117] Application Example 2 is repeated except that compound (A-5) is replaced by compound (A-6) and the emitting layer consists of 90.7% by weight of mCBP and 9.3% by weight of compound (A-6).

Application Example 4

[0118] An organic light emitting device (OLED) is fabricated by vacuum deposition of ITO (100 nm)/N-[4-[4-[N-(1-naphthyl)anilino]phenyl]phenyl]-N-phenyl-naphthalen-1-amine (?-NPD, 30 nm)/4-carbazol-9-yl-N,N-bis(4-carbazol-9-ylphenyl)aniline (TCTA, 20 nm)/[9-(4-tert-butylphenyl)-6-triphenylsilyl-carbazol-3-yl]-triphenyl-silane (CzSi, 10 nm)/82% by weight of bis(2-(diphenylphosphino)phenyl)ether oxide (DPEPO): 18% by weight of compound

##STR00177##

(20 nm)/DPEPO (10 nm)/2-[3,5-bis(1-phenylbenzimidazol-2-yl)phenyl]-1-phenyl-benzimidazole (TPBi, 30 nm)/LiF (0.8 nm)/Al (100 nm) on a glass substrate, subsequently the device is encapsulated and the performance of the device is evaluated.

Application Example 5

[0119] Application Example 2 is repeated except that compound A-5 is replaced by compound

##STR00178##

and the emitting layer consists of 87% by weight of mCBP and 13% by weight of compound (A-8).

Application Example 6

[0120] Application Example 2 is repeated except that compound A-5 is replaced by compound

##STR00179##

and the emitting layer consists of 88% by weight of mCBP and 12% by weight of compound (A-9).

TABLE-US-00002 TABLE 2 EL performance of the devices of Application Examples 3 to 6 Appl. Example Emitting compound EQE (%) Emission peak (nm) 3 A-6 11.9 569 4 A-7 15.7 516 5 A-8 7.6 543 6 A-9 14.1 542

[0121] The devices of Application Examples 3 to 6 show emission peaks at 516 to 569 nm in EL spectrum with EQEs of 7.6 to 15.7%, which are higher than the theoretical value of conventional fluorescent materials (EQE=5-7.5%).