Highly Efficient Single‐Layer Polymer Electrophosphorescent Devices

A commercially available Ir complex has been employed for the preparation of highly efficient (see Figure) single‐layer phosphorescent polymer light‐emitting diodes by use of appropriate thermal treatment and proper adjustment of the layer composition. These devices exhibit essentially no dependence of the driving field on the concentration of the Ir complex, suggesting that the build‐up of space‐charge in the layer is insignificant.