Effect of drying behavior-induced self-organization process on the morphology and electronic properties of conjugated polymer films

Abstract

In this study, the morphology and electronic properties of semiconducting polymer films were investigated in relation to a different drying behavior induced by the spinning time variation. Morphology changes related to the decreased spinning time were evaluated for p-type (P3HT, PQT-12) and n-type (N2200, PDBPyBT) polymer films fabricated at different preparation conditions. Based on the improved morphology, OFET devices were fabricated showing a 2.5 times carrier mobility increase (0.044 ± 0.012 cm2V−1s−1 for 3 s spin to 0.018 ± 0.011 cm2V−1s−1 for 30 s spin) for P3HT films, and 3 times improvement (0.088 ± 0.023 cm2V−1s−1 for 50 s to 0.28 ± 0.017 cm2V−1s−1 for 5 s) for N2200 films. For short spinning times, the slow drying of residual solvent allowed for the self-organization of polymer chains improving the crystallinity of polymer films. The presented approach synergizes the benefits of the spin coating method, like highly controlled film uniformity and thickness, with improved film morphology provided by other methods, like drop casting, or dip-coating.