New copper-based materials for White Light-emitting Electrochemical Cells (LEC) applications

Light-emitting Electrochemical Cell (LEC) has emerged as a simple lightning technology. Indeed, these devices involve only one emitting layer containing an ionic emitter. Phosphorescent cationic organometallics are good candidates but they are usually based on expensive noble metals. Cationic copper (I) complexes exhibiting potential Thermally Activated Delayed Fluorescence (TADF) can offer an interesting alternative. In this context, we have developed cationic tricoordinated copper complexes bearing N-Heterocyclic Carbene (NHC) and bis-pyridyl derivatives as ligands [Cu(NHC)(N^N)] [PF6]. By varying the electronic properties on both ligands, some structure/properties relationships, supported by structural, photophysical and Time-Dependent Density Functional Theory (TD-DFT) studies, were established. Some of these complexes led to the first blue LEC but showed moderate stability over time. Our next goal is to develop more stable complexes and red emitters for application in white LECs