Synthesis, Properties, Crystal Structures, and Semiconductor Characteristics of Naphtho[1,2-<i>b</i>:5,6-<i>b</i>′]dithiophene and -diselenophene Derivatives

In this paper we present the synthesis, structures, characterization, and applications to field-effect transistors (FETs) of naphtho[1,2-b:5,6-b′]dithiophene (NDT) and -diselenophene (NDS) derivatives. Treatment of 1,5-dichloro-2,6-diethynylnaphthalenes, easily derived from commercially available 2,6-dihydroxynaphthalene, with sodium chalcogenide afforded a straightforward access to NDTs and NDSs including the parent and dioctyl and diphenyl derivatives. Physicochemical evaluations of NDT and NDS derivatives showed that these heteroarenes have a similar electronic structure with isomeric [1]benzothieno[2,3-b][1]benzothiophene (BTBT) and [1]benzoselenopheneno[2,3-b][1]benzoselenophene (BSBS) derivatives, respectively. Although attempts to fabricate solution-processed field-effect transistors (FETs) with soluble dioctyl-NDT (C8-NDT) and -NDS (C8-NDS) failed, diphenyl derivatives (DPh-NDT and DPh-NDS) afforded vapor-processed FETs showing field-effect mobility as high as 0.7 cm2 V−1 s−1. These results indicated that NDT and NDS are new potential heteroarene core structures for organic semiconducting materials.