Fluorinated Dihydropentalene‐1,4‐Dione: A Strong Electron‐Accepting Unit with Organic Semiconductor Characteristics

Abstract

AbstractThe development of electron‐accepting units is of significant importance because the construction of donor (D)‐acceptor (A) configurations is an effective strategy for tuning the electronic properties of π‐conjugated systems. Although doubly fused pentagons represented by diketopyrrolopyrrole (DPP) have been used as an effective electron‐accepting unit, the relatively high‐lying frontier molecular orbital levels (FMOs) leave room for further improvement. We report herein the synthesis of a fluorinated dihydropentalene‐1,4‐dione (FPD) derivative as a strong electron‐accepting unit and the development of D−A−D π‐extended molecules. X‐ray analyses revealed that the presence of fluorine atoms contributed to the formation of high planar structures and slipped‐stacked packing. Electrochemical measurements indicated that the FPD derivatives showed relatively lower FMO energy levels than the corresponding DPP‐containing derivatives. The D−A−D molecule based on terthiophene and FPD showed semiconducting responses. This study demonstrates that the FPD unit can function as a new acceptor unit for organic semiconductors.