Directly Spin Coating a Low‐Viscosity Organic Semiconductor Solution onto Hydrophobic Surfaces: Toward High‐Performance Solution‐Processable Organic Transistors
Shuya Wang, Xiaoli Zhao, Yanhong Tong, Qingxin Tang, Yichun Liu
Abstract
Abstract Solution‐processable organic thin‐film transistors (OTFTs) have attracted considerable attention owing to their low cost, low‐temperature preparation, and compatibility with flexible substrates. Spin‐coating is the simplest and most common method for manufacturing large‐area OTFTs; it can be challenging, however, to spin‐coat high‐quality, uniform organic semiconductor films onto hydrophobic surfaces. The use of such surfaces is vital for improving device performance. In this work, through theoretical calculation of the spreading parameter and wetting envelope, the wetting behavior of organic semiconductor solutions on hydrophobic dielectrics is quantitatively analyzed. Based on the theoretical findings, organic‐semiconductor‐solution surface tension is systematically adjusted to solve the common wettability issues. The crystallinity of the wettable organic semiconductor film is also significantly improved by a post‐annealing performed at even lower temperature. As a result, fabricated 6,13‐bis(triisopropylsilylethynyl)‐pentacene OTFTs show excellent electrical characteristics, with mobility and current on/off ratios up to 1.66 cm 2 V −1 s −1 and 7 × 10 9 , respectively. This work provides general guidance for solving wettability issues, that can lead to the development of new‐generation, high‐performance, solution‐processable, organic electronic devices.