Thieno[2,3,a]carbazole donor-based organic dyes for high efficiency dye-sensitized solar cells

A new series of donor-π-acceptor organic K-dyes based on the thieno[2,3,a]carbazole moiety as a new electron donor, trithiophene as a π-linker and cyanoacrylic acid as an electron acceptor were designed and synthesized for achieving high performances in dye-sensitized solar cells (DSCs). The substituent effect and the molecular planarity for photophysical properties and DSC performances of K-dyes have been investigated, and the highest power conversion efficiency of 7.4% has been achieved. EIS and IMVS were employed to study the effect of the molecular structure on the charge transfer process and electron lifetime.