Polarized polymer light-emitting electrochemical cells using polyfluorene and polycaprolactone blend film by floating-film transfer method

Sandwich-type structured polarized Polymer Light-emitting Electrochemical Cells (PLECs) of poly (9,9-dioctylfluorene) (PFO) successfully fabricated by a combination of floating-film transfer method (FTM) and Post-blending ionic liquid (IL) procedure. An ion-solvating polymer, polycaprolactone (PCL), was blended in PFO to improve IL penetration. The PFO:PCL film showed clear optical dichroism due to the PFO backbone orientation. The IL, 1-Ethyl-3-methylimidazolium (trifluoromethylsulfonyl)imide (EMIm-TFSI), easily post-blended into the PFO:PCL blend FTM film without disordering PFO backbone orientation. The fabricated thickness-varied PLECs with ITO anode and aluminum cathode demonstrated distinct anisotropy, whole device area emission, and low turn-on voltage compared to PLEDs.