Photo-Cross-Linkable Polyfluorene–Triarylamine (PF–PTAA) Copolymer Based on the [2 + 2] Cycloaddition Reaction and Its Use as Hole-Transport Layer in OLEDs

Abstract

We report the synthesis and characterization of a cross-linkable, cinnamic acid functionalized, hole-transporting polyfluorene–triarylamine (PF–PTAA) copolymer. Irradiation with light induces [2 + 2] cycloaddition and renders thin films of this polymer insoluble. Spin-coated films of the polymer and their light-induced cross-linking were investigated by atomic force and electron microscopy. In a proof-of-principle multilayer OLED device the polymer was applied as hole-transport layer (HTL) with commercially available F8BT as emitting layer (EML). Compared to the reference device without HTL we observe a significant increase in OLED performance. These results promise progress in cost-effective large area fabrication of polymer-based multilayer OLEDs with superior performance.