Perylenebisimide regioisomers: Effect of substituent position on their spectroscopic, electrochemical, and photovoltaic properties

Abstract

New disubstituent fluorinated perylenebisimide regioisomers were synthesized and characterized. The single-crystal structure of a 1,6-disubstituted perylenebisimide was elucidated for the first time, which revealed that the molecules are arranged in stacks along the b-axis of the unit cell and share more than 50% of their core surface. Owing to the steric encumbrance of the substituents, the perylene cores were highly twisted. The effect of substituent positions on their spectroscopic, electrochemical, and photovoltaic properties were also examined. Moreover, the two substituent positions on perylenebisimides were found to have a large impact on the solar cell performance. Different perylenebisimide regioisomers made an impact on open circuit voltage, but strongly affected the short circuit current density, indirectly influencing the overall photovoltaic performance of the device.