Dibenzothiopheno[6,5-b:6′,5′-f]thieno[3,2-b]thiophene (DBTTT): High-Performance Small-Molecule Organic Semiconductor for Field-Effect Transistors

We present the synthesis, characterization, and structural analysis of a thiophene-rich heteroacene, dibenzothiopheno[6,5-b:6′,5′-f]thieno[3,2-b]thiophene (DBTTT) as well as its application in field-effect transistors. The design of DBTTT is based on the enhancement of intermolecular charge transfer through strong S–S interactions. Crystal structure analysis showed that the intermolecular π–π distance is shortened and that the packing density is higher than those of the electronically equivalent benzene analogue, dinaphtho-[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DNTT). The highest hole mobility we obtained in polycrystalline DBTTT thin-film transistors was 19.3 cm2·V–1·s–1, six times higher than that of DNTT-based transistors. The observed isotropic angular mobilities and thermal stabilities at temperatures up to 140 °C indicate the great potential of DBTTT for attaining device uniformity and processability.