Researchers from the Max Planck Institute for Polymer Research developed a way to improve the current injection from the positive electrode in OLED panels. To enhance the hole injection the researchers covered the positive electrode with an ultrathin layer of an organic semiconductor as a spacer layer between the electrode and the light-emitting organic semiconductor.

Current flowing through an OLED (Max Planck Institute for Polymer Research)Current flowing from an electrode (left) to the organic material (right) via a thin molecular layer (center)

The researchers say that they did not actually expect that adding an extra layer and eliminating the physical contact between the electrode and the emitting layer actually improves the electrical contact.