Insights into the influence of fluorination positions on polymer donor materials on photovoltaic performance

Three novel donor-acceptor (D-A) alternative copolymers PHF, PFH and PFF were synthesized and applied for polymer solar cells (PSCs) to explore the influence of fluoro substitution position and number on optical, electrochemical and photovoltaic properties. PHF, PFH and PFF based PSCs gave power conversion efficiencies of 7.2%, 6.19% and 2.9%, respectively. TEM and R-SoXS studies indicated that the introduction of four fluorine atoms at each repeating unit can spoil the morphology of active layer.249