Design of a Quinoidal Thieno[3,4-b]thiophene-Diketopyrrolopyrrole-Based Small Molecule as n-Type Semiconductor.

A quinoidal small-molecule semiconductor QDPPBTT was synthesized. Organic thin-film transistor (OTFT) devices based on QDPPBTT showed an electron mobility as high as 0.13 cm2  V-1  s-1 and Ion /Ioff ratio of 106 under ambient conditions. We suggested that 2D extended π-conjugation and quinoid-enhancing effect had an important role in electron mobility and stability of n-type FET devices, which might be a good strategy in designing new material systems.