Interlayers of conjugated luminescent polymers formed on top of PEDOT:PSS, prior to the deposition of the polymeric electroluminescent layer, have been shown to lead to improvements of light-emitting diodes performance. Such interlayers can improve charge balance within the emissive layer or reduce exciton quenching by PEDOT:PSS. We have been studying the use of regular and crosslinkable polymers to form such interlayers and used AFM and conductive AFM to characterise them. In particular, we aim to clarify the anchoring points of the conjugated polymer chains when an incomplete coverage of the PEDOT:PSS surface occurs.
I this communication I will present some of our recent results related to the use of different polymers to form interlayers aiming to determine the nature of the interactions leading to their formation. We have been using regular polyfluorenes and polyfluorenes functionalised with oxetanes, which undergo a ring opening reaction catalised by the acidic PEDOT:PSS, leading to the formation of crosslinked interlayers.