Abstract:
Growth of two-dimensional (2D) organic single crystals (2DOSCs) on water surface has attracted increasing attention, because it can serve as a molecularly flat and defect-free substrate. However, large-area growth of 2DOSCs with controllable crystal orientation on water surface remains a key challenge. Herein, we develop a simple method, i.e. external-force-driven solution epitaxy (EFDSE), for the large-area growth of 2DOSCs at air/water interface. Using 2,7-didecylbenzothienobenzothiophene (C10-BTBT) as an example, high-quality 2D C10-BTBT crystals on centimeter scale are generated by directionally controlling the spreading of organic solution on water surface with external force. Benefiting from the controllable crystal orientation with optimal charge transport, the corresponding 2DOSC-based organic field-effect transistors (OFETs) exhibit a high carrier mobility of 13.5 cm2·V-1·s-1 (effective mobility ≈ 5.4 cm2·V-1·s-1 according to a reliability factor of 40%), which represents the best result achieved for water-surface-assembled 2DOSC-based OFETs. Furthermore, by transferring the C10-BTBT 2DOSCs to flexible substrates, devices with excellent bending stability are achieved. It is anticipated that our method will provide new insight into the controllable growth of large-area 2DOSCs for high-performance organic devices.
链接：https://link.springer.com/article/10.1007/s12274-019-2515-4
