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.