Small Molecule Near-Infrared Boron Dipyrromethene Donors for Organic Tandem Solar Cells.

Three furan fused boron dipyrromethenes (BODIPYs) with a CF group on the meso-carbon are synthesized as near-infrared absorbing materials for vacuum processable organic solar cells. The best single junction device reaches a short-circuit current (j) of 13.3 mA cm and a power conversion efficiency (PCE) of 6.1%. These values are highly promising for an electron donor material with an absorption onset beyond 900 nm. In a tandem solar cell comprising a NIR BODIPY subcell and a matching "green" absorber subcell, complementary absorption is achieved, resulting in PCE of ∼10%.