Two-dimensional (2D) crystals of organic semiconductors (2DCOS) have attracted attention for large-area and low-cost flexible optoelectronics. However, growing large 2DCOS in controllable ways and transferring them onto technologically important substrates, remain key challenges. Herein we report a facile, general, and effective method to grow 2DCOS up to centimeter size which can be transferred to any substrate efficiently. The method named "solution epitaxy" involves two steps. The first is to self-assemble micrometer-sized 2DCOS on water surface. The second is epitaxial growth of them into millimeter or centimeter sized 2DCOS with thickness of several molecular layers. The general applicability of this method for the growth of 2DCOS is demonstrated by nine organic semiconductors with different molecular structures. Organic field-effect transistors (OFETs) based on the 2DCOS demonstrated high performance, confirming the high quality of the 2DCOS.

The application of three-dimensional (3D) plasmonic nanostructures as metamaterials (MMs), nano-antennas, and other devices faces challenges in producing metallic nanostructures with easily definable orientations, sophisticated shapes, and smooth surfaces that are operational in the optical regime and beyond. Here, we demonstrate that complex 3D nanostructures can be readily achieved with focused-ion-beam irradiation-induced folding and examine the optical characteristics of plasmonic ''nanograter'' structures that are composed of free-standing Au films. These 3D nanostructures exhibit interesting 3D hybridization in current flows and exhibit unusual and well-scalable Fano resonances at wavelengths ranging from 1.6 to 6.4 mm. Upon the introduction of liquids of various refractive indices to the structures, a strong dependence of the Fano resonance is observed, with spectral sensitivities of 1400 nm and 2040 nm per refractive index unit under figures of merit of 35.0 and 12.5, respectively, for low-order and high-order resonance in the near-infrared region. This work indicates the exciting, increasing relevance of similarly constructed 3D free-standing nanostructures in the research and development of photonics and MMs.