Devices are provided having an anode, a cathode, and an emissive layer
disposed between and electrically connected to the anode and the cathode.
The emissive layer includes an emissive material having more than one
metal center. In one embodiment, first and second metal centers are
independently selected from the group consisting of d7, d8 and d9 metals.
A bridging ligand is coordinated to the first metal center and to the
second metal center. In one embodiment, the first and second metal
centers each have coordination numbers of at least 3, and more preferably
each have coordination numbers of 4. In one embodiment, photoactive
ligands are coordinated to the first and second metal centers. In one
embodiment, there are no photoactive ligands. In one embodiment, a charge
neutral bi-nuclear emissive material is provided. In one embodiment the
first and metal centers have a co-facial configuration, and preferably a
square planar co-facial configuration. In one embodiment, the metal
centers are selected from metals having an atomic number greater than or
equal to 40.