Molecular design of porphyrin dyes using different electron-withdrawing moieties for high performance dye-sensitized solar cells

Abstract

In spite of having some favorable light harvesting properties, porphyrins are still inferior to ruthenium dyes in dye sensitized solar cells. Nevertheless, there are enormous scope for improving the efficacy of these dyes. To recognize the connection between the structure and light-harvesting properties, herein, we have made a systematic theoretical investigation on a series of Zn-porphyrin dyes. We have explored the effect of benzodithiazole based model acceptor groups on their photovoltaic properties, especially on the electron injection dynamics with TiO2 photoanode. The model dyes show enhance light absorption in the entire visible region of solar spectrum in comparison to the parent dye which has been synthesized recently. The interfacial electron transfer (IET) dynamics reveals that suitable heteroatom substitution in acceptor group offers faster (sub-picosecond) electron injection as compared to the parent dye.