Synthesis of Highly Photostable Benzoindolenine-Based Squaraine Dyes by using Aromatic Fluorine Atoms

摘要

We have elucidated the details of the photodegradation of non-fluorinated benzoindolenine-based SQ dyes with low photostability in solution and proposed a hypothesis to improve their photostability. Based on the results, replacing all the hydrogen atoms on the benzoindolenine ring with fluorine atoms or methylation of the oxygen anions of the non- fluorinated benzoindolenine SQ dye resulted in improvement of photostability. Furthermore, a preliminary investigation of the synthesized SQ dyes for organic photovoltaics revealed that the O-methylated SQ dye with bulky fluorine-containing anions provided a much higher V_(oc) than similar benzoindolenine-based SQ dyes.