A narrow band gap isoindigo based molecular donor for solution processed organic solar cells

Abstract

The synthesis and characterization of a novel isoindigo based small molecule semiconductor is reported. The new compound exhibits broad and efficient optical absorption extending beyond 800 nm, relatively low lying HOMO and LUMO energy levels of −5.14 and −3.69 eV, respectively, and good solubility in common organic solvents. When paired with PC₆₁BM, organic solar cells gave power conversion efficiencies as high as 3.2%, among the highest achieved for small molecule isoindigo based systems.