Abstract: 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; R1 is a substituent; n is 0 or a positive integer; Ar1 independently in each occurrence is an arylene group; R2 is a substituent; R3 is a substituent; R4 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.

Abstract: A compound of formula (I) or (III) (Formulae (I), (III)) wherein: one Y is a substituent R1 bound directly to the fluorene unit of formula (I) by an sp3-hybridised carbon atom; the other Y is an aryl or heteroaryl group Ar1 that may be unsubstituted or substituted with one or more substituents; Ar2 is an arylene or heteroarylene group; R2 is a substituent; b is 0, 1, 2, 3 or 4; c is 0, 1, 2 or 3; and X is a group of formula (II): (Formula (II)) wherein Z is O or S; R3 independently in each occurrence is a substituent; each x is independently 0, 1, 2 or 3; and * is a bond to the fluorene unit of formula (I). The compounds may be used as host materials for phosphorescent dopants in organic light-emitting devices.

Abstract: An organic white light-emitting device comprising an anode, a cathode and at least one light-emitting layer between the anode and the cathode, wherein a first light-emitting layer comprises a first light-emitting compound of formula (I): wherein R1, R2 and R3 independently in each occurrence is a substituent; M1 is a transition metal; L1 is a ligand other than a ligand of formula: (II) a and b are each 0 or a positive integer; x is at least 1; and y is 0 or a positive integer, a light-emitting layer of the device comprising at least one further light-emitting material.

Abstract: A phosphorescent compound of formula (I): wherein: M is a transition metal; C1 is a carbon atom forming a metal-carbene bond with M; A is a saturated bridged bicyclic or saturated bridged tricyclic group consisting of one nitrogen atom and 6-12 carbon atoms; either: (i) X1 is a bridgehead carbon atom of the bridged bicyclic or bridged tricyclic group and X2 is NR1 wherein R1 is a substituent, or (ii) X1 is N and X2 is a bridgehead group of formula CR6 wherein R6 is H or a substituent; Ar1 is a C6-20 aromatic group or a 5-20 membered heteroaromatic group; L in each occurrence is independently a mono- or poly-dentate ligand other than a ligand of formula A-Ar1; x is at least 1; and y is 0 or a positive integer. The compound of formula (I) may be used as a blue light-emitting material in a white organic light-emitting device.

Abstract: A compound of formula (I): wherein M is a transition metal; Ar1 is a 5 or 6 membered heteroaryl ring or a polycyclic heteroaromatic group; Ar2 is a polycyclic group comprising two or more rings selected from aromatic and heteroaromatic rings; Ar1 and Ar2 may be linked by a direct bond or divalent linking group; L is a ligand; x is at least 1; a, b and y are each 0 or a positive integer; R1, R2 and R3 are each independently a substituent; and (i) Ar1 is a polycyclic heteroaromatic group; or (ii) Ar1 is a 5 or 6 membered heteroaryl ring and Ar2 is a polycyclic group comprising at least 3 rings selected from aromatic and heteroaromatic rings. The compound may be used as an infra-red emitting material of an organic light-emitting device.

Abstract: A phosphorescent compound of formula (I): wherein M is a transition metal; L is a ligand; R1 is a branched C3-20 alkyl group, a cyclic C5-20 alkyl group or group of formula (II): wherein each R5 is a C1-10, alkyl group; each R6 is a substituent; z is 0 or a positive integer; R2 is a C1-10 alkyl group; R3 is a C1-10 alkyl group or a group of formula —(Ar1)p wherein Ar1 is aryl or heteroaryl group and p is at least 1; each R4 is independently a substituent; v is at least 1; w is 0 or a positive integer; x is at least 1; and y is 0 or a positive integer. The compound may be used as a blue light-emitting material in an organic light-emitting device.

Abstract: A light-emitting polymer comprising a light-emitting repeat unit in a backbone of the polymer, wherein the polymer has an anisotropy of no more than 0.8 and wherein a transition dipole moment of the light-emitting repeat unit is aligned with the polymer backbone.

Abstract: An organic light-emitting device comprising an anode; a cathode; and a first light- emitting layer between the anode and the cathode, wherein the first light-emitting layer comprises a fluorescent light-emitting material of formula (I): wherein Ar1 independently in each occurrence is a substituted or unsubstituted aryl or heteroaryl group and each R1 is independently H or a substituent; and wherein a first phosphorescent light-emitting material is provided in the first light-emitting layer or in a second light-emitting layer adjacent to the first light-emitting layer.

Abstract: A compound of formula (I) wherein M is a transition metal; L is a ligand; x is at least 1; y is 0 or a positive integer; R1 in each occurrence is independently a substituent; R2 and R3 in each occurrence is independently H or a substituent, with the proviso that at least one of R1, R2 and R3 is a group X comprising at least one aryl or heteroaryl group. The compound of formula (I) may be used as a phosphorescent material in an organic light-emitting device.