Synthesis of a polythieno[3,4-b]thiophene derivative with a low-lying HOMO level and its application in polymer solar cells

A planar benzodithiophene with lower HOMO was copolymerized with the thieno[3,4-b]thiophene unit to obtain a new low band gap polymer of PBDPTT-C, which exhibited a higher open-circuit voltage (V-oc) of 0.8 V and a promising efficiency of 5.2%.