Abstract
In this review paper, we summarize the series of semiconducting polymers based on the thiazolothiazole heteroaromatic ring in terms of the molecular design, thin film structures and photovoltaic properties. The polymers formed crystalline structures that facilitate charge transport in thin films. Interestingly, the polymers having branched alkyl groups as the side chain, were found to change their backbone orientation, namely “edge-on” and “face-on”, by the molecular weight, side chain composition, and addition of the fullerene derivative. The change in the orientation greatly affected their photovoltaic properties of the solar cells. These results will provide new insight into the design of high-performance semiconducting polymers.
