This Letter reports the novel use of poly(9-vinylcarbazole) (PVK) as a dielectric interfacial layer for n-type organic field-effect transistors (n-OFETs). With PVK, both the air stability and electron mobility of N,N′-ditridecylperylene-3,4,9,10-tetracarboxylic diimide (PTCDI-C13)-based OFETs were improved. Among the PVKs with different weight-average molecular weight (Mw), PVK with high Mw showed good performance. The high glass transition temperature of PVK enabled thermal post annealing of the active layer, which resulted in a high electron mobility of 0.61 cm2/Vs. This mobility was maintained at 90% and 59% after 4 days and 105 days in air, respectively. The PVK interfacial layer reduced the trapped charges in the PTCDI-C13-based n-OFET for air-exposure and caused a decrease in the threshold voltage shift.
(© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)