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 (mu(max) = 7.5 x 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 x 10(-2) to 7.4 x 10(-2) cm(2) V-1 s(-1) for one to three sulfurs.