Enhanced electron mobility in crystalline thionated naphthalene diimides

A series of five thionated naphthalene diimides (NDIs) with linear alkyl chains was synthesized and the optoelectronic, self-assembly, and device properties were studied. When tested in organic thin-film transistors, the electron mobilities of the thionated derivatives are three orders of magnitude higher than the non-thionated parent analogue, with the highest mobility measured for cis-S2 ( μ max = 7.5 × 10 −2 cm 2 V −1 s −1 ). In contrast to branched chain PDIs and NDIs, the electron mobility does not increase appreciably with degree of thionation, and the average mobilities are quite consistent ranging from 3.9 × 10 −2 to 7.4 × 10 −2 cm 2 V −1 s −1 for one to three sulfurs.