Ion Transport beyond the Polyether Paradigm: Introducing Oligocarbonate Ion Transporters for Efficient Light‐Emitting Electrochemical Cells

The light‐emitting electrochemical cell (LEC) is fundamentally dependent on mobile ions for its operation. In polymer LECs, the mobile ions are commonly provided by dissolving a salt in an ion transporter, with the latter almost invariably being an ether‐based compound. Here, the synthesis, characterization, and application of a new class of carbonate‐based ion transporters are reported. A polymer LEC, comprising a star‐branched oligocarbonate endowed with aliphatic side groups as the ion transporter, features a current efficacy of 13.8 cd A^?1 at a luminance of 1060 cd m^?2, which is a record‐high efficiency/luminance combination for a singlet‐emitting LEC. It is further established that the design principles of a high‐performance carbonate ion transporter constitute the selection of an oligomeric structure over a corresponding polymeric structure and the endowment of the oligomer with functional side chains to render it compatible with the polymeric emitter.