Molecular design of organic sensitizers absorbing over a broadened visible region for dye-sensitized solar cells

Abstract

A group of sensitizers P1–P7, as well as the reference molecule XS54, were theoretically designed and investigated, and the properties of photo-induced charge transfer were characterized by density functional theory (DFT) and time-dependent density functional theory (TD-DFT). Research shows that P5 and P6 possess a broad spectral response, and exhibit strong electron migration ability along the conjugated bridge. The benzothiadiazole (BTD) unit being placed near the accepter unit can effectively extend the spectral range and improve the electron delocalization. Our theoretical design promotes the deeper understanding of dye-sensitized solar cells that absorb over a broad visible region.