New dithienosilole- and dithienogermole- based BODIPY for solar cell applications

We report two efficient donor materials for organic solar cells, namely Si- BDP and Ge- BDP, composed by the novel union of thienyl Bodipy wings and a dithienosilole/ dithienogermole core. These new donor molecules exhibited excellent solubility in organic solvents, extended p- conjugation and low- lying energy levels that matched with fullerene acceptors, supporting their application as donors in OSCs. Under optimized conditions and using PC70BM as an acceptor, desirable PCEs of 4.58% and 4.12% were observed for Si- BDP and Ge- BDP, respectively.