Efficient single-component light-emitting electrochemical cells with an ion-conducting water-soluble polyfluorene

Polymer light-emitting diodes (PLEDs) and light-emitting electrochemical cells (LECs) were fabricated using a water-soluble conjugated polymer with ion-conducting side chains. The water-soluble polymer was spin-coated on the emitting layer of a PLED and was used as an electron-injecting layer. The PLED showed enhanced performance with LEC behavior due to both the mobile ions and ion-conducting side groups of the polymer. A single-component and single-layer device was also fabricated, which showed typical LEC behavior with 1.13% maximum external quantum efficiency after complete ion migration.