BODIPY-based panchromatic chromophore for efficient organic solar cell

A novel donor-acceptor-donor (D-A-D) type chromophore, named BDP-dBDT, with a boron dipyrromethene (BODIPY) linked through alkynyl with two benzo [l,2-b:4,5-b']dithiophene (BDT) terminal donors was designed and synthesized for solution-processed small molecule bulk heterojunction (BHJ) solar cell. The thermal and optochemical properties, BHJ morphology and solar cell performance were investigated. The new molecule shows panchromatic absorption with narrow optical band gap and high molar extinction coefficient. Moreover, the molecule displays deep highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels. The BHJ morphology was systematically optimized by additives, thermal annealing (TA) and solvent vapor annealing (SVA). Processed by a combination of TA and SVA treatments, the BDP-dBDT:PC71BM device exhibits a short-circuit current density (J(sc)) of 12.98 mA cm(-2), and a power conversion efficiency (PCE) of 5.61%, which is one of the best values among the ever reported BODIPY based organic solar cells.