Photovoltaic Devices Prepared through a Trihydroxy Substitution Strategy on an Unsymmetrical Squaraine Dye

Squaring away symmetry : A series of unsymmetrical squaraine derivatives containing two, three, or four hydroxy substituents have been designed and synthesized to investigate the effect of the number of hydroxy groups on the optoelectronic properties of squaraine derivatives. Results reveal that the trihydroxy‐substituted unsymmetrical squaraine shows the best photovoltaic performance (see figure).