Organic Semiconductor Crystal Engineering for High-Resolution Layer-Controlled 2D Crystal Arrays.

2D organic semiconductor crystals (2DOSCs) have extraordinary charge transport capability, adjustable photoelectric properties, and superior flexibility, and have stimulated continuous research interest for next-generation electronic and optoelectronic applications. The prerequisite for achieving large-area and high-throughput optoelectronic device integration is to fabricate high-resolution 2DOSC arrays. Patterned substrate- and template-assisted self-assembly is an effective strategy to fabricate OSC arrays. However, the film thickness is difficult to control due to the complicated crystallization process during solvent evaporation. Therefore, the manufacturing of 2DOSC arrays with high-resolution and controllable molecular-layer numbers through solution-based patterning methods remains a challenge. Herein, a two-step strategy to produce high-resolution layer-controlled 2DOSC arrays is reported. First, large-scale 2DOSCs with well-defined layer numbers are obtained by a solution-processed organic semiconductor crystal engineering method. Next, the high-resolution layer-controlled 2DOSC arrays are fabricated by a polydimethylsiloxane mold-assisted selective contact evaporation printing technique. The organic field-effect transistors (OFETs) based on 2DOSC arrays have high electrical performance and excellent uniformity. The 2,6-bis(4-hexylphenyl)anthracene 2DOSC arrays-based OFETs have a small variation of 12.5% in mobility. This strategy can be applied to various organic semiconductors and pattern arrays. These demonstrations will offer more opportunities for 2DOSCs for integrated optoelectronic devices.