Solution-processable double-layered ionic p-i-n organic light-emitting diodes

► We study solution-processed double-layered organic light-emitting diodes (OLEDs), which comprise an EML and a photo-crosslinkable HTL. ► The EML was doped with ionic salt and the double layers were annealed using simultaneous thermal and electrical treatments, resulting in the formation of a bright and efficient ionic p-i-n structure. ► Annealing treatments can lead to the increased and balanced injection of carriers in solution-processed double-layered OLEDs.