2D molecular crystals (2DMCs) have attracted considerable attention because of their unique optoelectronic properties and potential applications. Taking advantage of the solution processability of organic semiconductors, solution self-assembly is considered an effective way to grow large-area 2DMCs. However, this route is largely blocked because a precise molecular design towards 2DMCs is missing and little is known about the relationship between 2D solution self-assembly and molecular structure. A "phase separation" molecular design strategy towards 2DMCs is proposed and layer-by-layer growth of millimeter-sized monolayer or few-layer 2DMCs is realized. High-performance organic phototransistors are constructed based on the 2DMCs with unprecedented photosensitivity (2.58 × 107 ), high responsivity (1.91 × 104 A W-1 ), and high detectivity (4.93 × 1015 Jones). This "phase separation" molecular design strategy provides a guide for the design and synthesis of novel organic semiconductors that self-assemble into large-area 2DMCs for advanced organic (opto)electronics.
Keywords: 2D molecular crystals; organic field-effect transistors; organic phototransistors; organic single crystals; phase separation.
© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.