Rylene diimide and dithienocyanovinylene copolymers for polymer solar cells

Two polymers containing (E-2,3-bis(thiophen-2-yl)acrylonitrile (CNTVT) as a donor unit, perylene diimide (PDI) or naphthalene diimide (NDI) as an acceptor unit, are synthesized by the Stille coupling copolymerization, and used as the electron acceptors in the solution-processed organic solar cells (OSCs). Both polymers exhibit broad absorption in the region of 300–850 nm. The LUMO energy levels of the resulted polymers are ca.–3.93 eV and the HOMO energy levels are–5.97 and–5.83 eV. In the binary blend OSCs with PTB7-Th as a donor, PDI polymer yields the power conversion efficiency (PCE) of up to 1.74%, while NDI polymer yields PCE of up to 3.80%.