Benzo[1,2-b:4,5-b’]dithiophene is a planar symmetrical molecular structure of the thiophene derivative, enabling a better π-π?stacking and good electron delocalization that encourages charge transport. In recent years, it has been intensively studied for the application of OFETs and OPVs. The incorporation of a low-band-gap unit into the benzo[1,2-b:4,5-b’]dithiophene unit could potentially result in a red-shifted absorption due to its electron-rich properties. Benzo[1,2-b:4,5-b’]dithiophene can be chemically modified to fine-tune its chemical structure and electron properties (e.g. band gap), energy levels, and charge mobility of the small molecule/polymers of interest (at a molecular level).
Benzo[1,2-b:4,5-b′]dithiophene-4,8-dione (BDTD) is a conductive polymer with a symmetric and planar conjugated structure which has a hole mobility of 0.25 cm2V-1s-1.