Dialkylated dibenzo[a,h]anthracenes for solution-processable organic thin-film transistors†

Abstract

Here, two alkylated dibenzo[a,h]anthracene (DBA) derivatives with linear n-dodecyl (C12-DBA-C12) and ring-containing pentyl-cyclohexyl (Cy5-DBA-Cy5) moieties were successfully synthesized. Their chemical and thermal stability were both notably high, with the molecular arrangement of C12-DBA-C12 and Cy5-DBA-Cy5 being greatly influenced by the alkyl groups. C12-DBA-C12 formed a 2D lamellar herringbone packing structure and its blade-coated film exhibited high layered crystallinity and high carrier mobility up to 2.97 cm² V⁻¹ s⁻¹. By contrast, the arrangement of Cy5-DBA-Cy5 in the crystal exhibited a packing motif where π-cores and alkyl chains were intertwined due to the C–H⋯π proximity of cyclohexyl moieties and DBA cores. Meanwhile, Cy5-DBA-Cy5 demonstrated relatively poor film-forming capacity and moderate mobility of about 0.45 cm² V⁻¹ s⁻¹. These findings could expand the possibilities of using DBA instead of pentacene in developing high-performance OSCs for organic electronics, and offer insights into manipulating molecular arrangement through alkyl engineering.