Panchromatic squaraines for hybrid and organic photovoltaic cells (G. Pagani, L. Beverina)

Squaraine compounds are currently investigated as high performing active component in both organic and hybrid photovoltaic devices as well as in field effect transistors. Their most valuable features include a particularly efficient optical absorption in the Vis-NIR region, high polarizability, electrochemical reversibility (at least concerning to their behaviour at oxidative potentials) and a remarkable chemical stability. Their full exploitation in photoconductive devices is somewhat limited by their negligible absorption in the UV-Vis region (prototypical squaraines basically do not absorb below 500 nm). Aim of our reserach is the design and synthesis of truly panchromatic squaraines to be employed both as the single active material in Vis operating photodetecting devices and, as the Donor, in organic photovoltaic devices. Our strategy involves the design of innovative squaraines that are both nonsymmetric and core-substituted with suitable electron-withdrawing substituents.