| abstract |
An unsubstituted or substituted phosphorescent compound of formula (I): n n n n n n n n n n n n Wherein: n M is a transition metal; n L in each occurrence is independently a mono- or poly-dentate ligand; n R 8 is H or a substituent; n R 9 and R 10 are each independently selected from the group consisting of branched, linear or cyclic C 1-20 alkyl wherein non-adjacent C atoms of the C 1-20 alkyl may be replaced with —O—, —S—, —NR 12 —, —SiR 12 2 — or —COO— and one or more H atoms may be replaced with F or —NR 12 2 , wherein R 12 is H or a substituent; n R 11 in each occurrence is independently H or a substituent, wherein two groups R 11 may be linked to form a ring; n x is at least 1; n y is 0 or a positive integer; n and z1, z2 and z3 are each independently 0 or a positive integer. |