High-Performance Triethylsilylethynyl Anthradithiophene Transistors Prepared without Solvent Vapor Annealing: The Effects of Self-Assembly during Dip-Coating

Solution-processable small-molecule organic semiconductors have recently attracted significant attention for use as the active channel layers in organic field-effect transistors due to their good intrinsic charge carrier mobility and easy processability. Dip-coating is a good method for optimizing the film morphology and molecular ordering of the small-molecular semiconductors because the drying speed can be quantitatively controlled at the air-solution-substrate contact line. Here, we report the preparation of highly crystalline triethylsilylethynyl-anthradithiophene (TES-ADT) crystal arrays that exhibit an excellent field-effect mobility (up to 1.8 cm(2)/(V s)) via an optimized one-step dip-coating process. High-quality TES-ADT crystals were grown without solvent vapor annealing postprocessing steps, which were previously thought to be essential for improving the morphology, crystallinity, and electrical characteristics of TES-ADT thin films. An interesting correlation between the optimal pull-out rate and the self-assembly tendencies of some soluble acene semiconductors was observed, and the origin of the correlation was investigated. Our work demonstrates an alternative simple approach to achieving highly crystalline TES-ADT thin films, and further proposes a prospective method for optimizing the formation of thin films via the molecular self-assembly of soluble acenes.This work was supported by a grant from the Korea Science and Engineering Foundation (KOSEF), funded by the Korea government (MEST) (2012-0000127), and by the PAL, XFEL projects, Korea