An organic light emitting device contains a cathode, an anode, and has located there-between a light emitting layer, comprising co-hosts including a hole transporting compound and a particular aluminum chelate, together with at least one light emitting Iridium compound, wherein the Iridium compound is a tris C^N-cyclometallated complex with a triplet energy less than or equal to the triplet energy of each of the co-hosts.