Large-Area Deposition of Highly Crystalline F4-Tetracyanoquinodimethane Thin Films by Molecular Step Templates

Theoretical studies have unequivocally determined the exceptional electron transport properties of the fluorinated tetracyanoquinodimethane (Fx-TCNQ) family, presenting a promising avenue for the realization of high-performance n-channel organic thin-film transistors (OTFTs). However, owing to the intrinsic low crystallinity of this class of materials, Fx-TCNQ-based n-channel OTFTs have not been experimentally achieved so far. Herein, a molecular step template (MST)-assisted method that dramatically improves the crystallinity of F4-TCNQ thin films is reported. The MST not only lowers the nucleation barrier of F4-TCNQ molecules along the in-plane direction but also reduces the nucleation density. This approach facilitates the realization of compact, oriented, and highly crystalline F4-TCNQ thin films, resulting in impressive electron mobility of up to 2.58 cm² V^-1 s^-1. Notably, this achievement surpasses the electron mobility of F4-TCNQ thin films fabricated without the MST by a factor of 10⁷. Furthermore, the incorporation of the p-type MST provides a novel pathway for constructing complementary inverters, showcasing a high voltage gain of 112.6 V V^-1 and a substantial noise margin of 89.3% with exceptional uniformity. In this work, a general and efficient route is paved to produce high-performance n-channel OTFTs toward organic complementary circuits.