A D-A copolymer of dithienosilole and a new acceptor unit of naphtho[2,3-c]thiophene-4,9-dione for efficient polymer solar cells.

A strong electron-withdrawing unit, naphtho[2,3-c]thiophene-4,9-dione, was copolymerized with dithienosilole to get a D-A copolymer, PDTSNTDO, with a narrow bandgap and lower-lying HOMO level. The PCE of the PDTSNTDO-based device reached 5.21%, with a high open circuit voltage of 0.88 V. This journal is © The Royal Society of Chemistry 2011