Quest for an Appropriate Electrolyte for High-Performance Light-Emitting Electrochemical Cells

The electrolyte plays a critical role in the operation of light-emitting electrochemical cells (LECs), and the LEC operational stability and efficiency can be severely limited by electrolyte-induced side reactions. Here we employ a trimethylolpropane-LiCF 3 SO 3 electrolyte with a particularly wide electrochemical stability window and for-the-purpose appropriate transport properties to minimize cathodic side reactions and to keep the emission zone free from electrolyte species during steady-state operation. We utilize an optimized blend of this electrolyte and the conjugated polymer superyellow as the active material sandwiched between air-stable electrodes, and we demonstrate that such LEC devices can exhibit a notably respectable operational lifetime (57 days of uninterrupted operation at a brightness of >100 cd/m 2 ) and a high efficiency (>10 lm/W at >100 cd/m 2 ).