Reduced Operating Voltages in Polymer Light‐Emitting Diodes Doped with Rare‐Earth Complexes

Light‐emitting diodes (LEDs) were fabricated using two europium complexes, differing only by the addition of tert‐butyl groups around the β‐diketonate ligands (see Figure), blended into poly(2‐(6′‐cyano‐6′‐methyl‐heptyloxy)‐1,4‐phenylene) (CN‐PPP). The addition of tert‐butyl groups results in CN‐PPP–Eu LEDs with increased operational lifetime and decreased operating voltage.