Morphology controlled synthesis of one-dimensional BTR micro-ribbons and two-dimensional single-crystal films for field-effect transistors

Single crystals have no grain boundaries, long-range order, and fewer traps and defects, making them an excellent carrier to explore the intrinsic properties and structure-property relationships of organic optoelectronic materials. Single crystals of a well-studied organic semiconductor used in organic solar cells, namely BTR, have been prepared in this work by a liquid-phase self-assembly method. By using appropriate solvents and the space-confined method, the morphology-controlled synthesis of one-dimensional (1D) BTR micro-ribbons and two-dimensional (2D) single-crystal films has been demonstrated. Both ac planes of the two single crystals are stacked parallel to the substrate with high quality, and the electrical properties of the single crystals were explored in field-effect transistors (FET). Field-effect transistors based on the BTR 2D crystal can achieve approximately an order better hole mobility than a spin-coated film. The single crystals with high intermolecular organization reveal the intrinsic charge transport properties of BTR.