Self-Assembled Photochromic Molecular Dipoles for High-Performance Polymer Thin-Film Transistors

The development of high-performance multifunctional polymer-based electronic circuits is a major step toward future flexible electronics. Here, we demonstrate a tunable approach to fabricate such devices based on rationally designed dielectric super-lattice structures with photochromic azobenzene molecules. These nanodielectrics possessing ionic, molecular, and atomic polarization are utilized in polymer thin-film transistors (TFTs) to realize high-performance electronics with a p-type field-effect mobility (μ_FET) exceeding 2 cm² V^-1 s^-1. A crossover in the transport mechanism from electrostatic dipolar disorder to ionic-induced disorder is observed in the transistor characteristics over a range of temperatures. The facile supramolecular design allows the possibility to optically control the extent of molecular and ionic polarization in the ultrathin nanodielectric. Thus, we demonstrate a 3-fold increase in the capacitance from 0.1 to 0.34 μF/cm², which results in a 200% increase in TFT channel current.