One-Step Deposition of Self-Oriented \beta-Phase Polyfluorene Thin Films for Polarized Polymer Light-Emitting Diodes

Uniaxially self-oriented centimeter-scale thin films of poly(9,9'-dioctylfluorene) (PFO) could be obtained with a one-step deposition by the floating-film transfer method (FTM) under ambient conditions. β-phase PFO was also generated along with the orientation direction during the film formation by FTM. Polarized β-phase electroluminescence having a maximum dichroic ratio of 7.7 was realized in bilayer polymer light-emitting diodes consisting of a self-oriented PFO film as the emission layer and a poly(9-vinylcarbazole) film as the hole-transporting and electron-blocking layer.