Surficial Marangoni Flow‐Induced Growth of Ultrathin 2D Molecular Crystals on Target Substrates

Abstract 2D molecular crystals (2DMCs) are emerging as excellent candidates for the application of organic field‐effect transistors (OFETs), owing to their enhanced charge transport efficiency and long‐range molecular ordering. However, many current methods involve an additional transfer process, which largely hinders the large‐area fabrication of high‐quality, intact 2DMCs for practical applications. Here, an efficient surficial Marangoni flow‐induced self‐assembly (SMFIS) method is developed for the fabrication of 2DMCs directly on target substrates without the need of a transfer process. This method utilizes a solvent/antisolvent system to confine the crystallization field at a liquid/air interface, and then the formed 2DMCs land on the target substrate with the full solvent evaporation. By controlling the vertical convection flow and the spreading coefficient of the solvent/antisolvent system, few‐layer (3–4 layers) 2DMCs are directly produced on the target substrates. The SMFIS method shows no substrate dependency and universal compatibility. With bis(triethylsilylethynyl)anthradithiophene (Dif‐TES‐ADT) as an example, the resulting 2D Dif‐TES‐ADT crystal exhibits an efficient charge transport with high average mobility up to 2.15 cm 2 V −1 s −1 . The proposed method with general applicability has great potential to be developed as a platform for the growth of high‐quality 2DMCs on the target substrate.