Synthesis and Characterization of Conjugated Polymers Based on Thieno[3,4‐b]Thiophene Quinoidal Unit

Abstract Driven by the success of quinoidal units for enabling high‐performance polymer semiconductors, herein a new quinoidal building block that terminated by indandione is reported. By introducing Br atoms into the terminal benzene rings of indandione, two CPs, P2TbTI‐DPP and P2TbTI‐TIID , are synthesized through Stille polycondensation. The strong electron‐withdrawing ability of indandione‐terminated quinoidal unit enables P2TbTI‐DPP and P2TbTI‐TIID with low‐lying LUMO energy levels of ≈–3.90 eV. Organic thin‐film transistors based on P2TbTI‐DPP and P2TbTI‐TIID exhibit n ‐type transport behavior. Besides, it is found that the electron mobility of these two polymers is weakly dependent on the annealing temperature due to the near‐amorphous of polymer thin‐film.