Further Examination of Interconnection in Conjugated Polymers for Organic Field‐Effect Transistors

Abstract

Abstract Conventional design principles toward conjugated polymers aiming at high organic field‐effect‐transistor (OFET) mobilities are directed at the establishment of extensive edge‐on π‐order. However, emerging principles state that efficient charge transport can be established through interconnected short‐range‐order polymer crystallites. Fractional side‐chain truncation has been employed to furnish numerous polymers. The electronic structures of the polymers are insensitive to side‐chain variation, whereas the thermal and morphological properties respond to it significantly. As the butyl side chain in the polymer backbone increases in size, the π‐order of the corresponding polymer thin film decreases gradually, while the π‐interconnection is enhanced. Moreover, the π‐anisotropy is transformed from face‐on to isotropy, which can be rationalized by the geometric shape of polymer crystallite. The OFET results disclose the beneficial effect of π‐interconnection to enhance the electron mobility. The significant role of π‐interconnection in the transport is further emphasized. An electron mobility of 0.31 cm 2 V −1 s −1 is accomplished, strongly suggesting that the modulation of π‐interconnection by fractional side‐chain truncation can serve as a straightforward approach to improving OFET electron mobility.