Layer-by-layer spin self-assembled hole injection layers containing a perfluorinated ionomer for efficient polymer light-emitting diodes

Deposition of hole injection layers including a perfluorinated ionomer has been demonstrated using layer-by-layer spin self-assembly for enhanced device efficiency and lifetime in PLEDs. We show that the LBL spin self-assembled thin films enable to control work functions of indium-tin oxide anodes by changing the PFI concentration and that a resulting green-emitting device has an enhanced luminescence efficiency and 18 times longer half lifetime than a device using a conventional HIL. We also fabricate a gradient of energy levels by the LBL self-assembly of the PFI that results in a work function of 5.74 eV, which can be used to improve carrier injection even for an emitting layer whose ionization potential is over 5.7 eV.