Polarized Electroluminescence from Aligned Chromophores by Friction Transfer Method

We have demonstrated that friction transfer technique can be used to align materials for LED devices. Friction transferred PTFE has a high density of ridges and grooves with height variations on the ten-nanometer scale. A variety of materials such as vacuum evaporated small molecules and solution soluble conjugated polymers can be easily aligned on friction transferred PTFE. Polarized LEDs fabricated on such surfaces showed high dichroic ratios. The device performance can be optimized by introducing a PEDOT layer to help improve the charge injection and wetting property. Addition of an electron transporting layer can further increase the external efficiencies of the polarized LED device.