Organic 1D nanomaterials based on low-molecular-weight semiconducting organic compounds are of interest because they possess unique properties for use in electronic, optoelectronic, and photonic nanodevices.[1] Different organic materials and methods have been employed to synthesize 1D single-crystal nanostructures. [2] While there are reports on fabricating organic 1D single crystals on specific device platforms, [3] relatively few of these reports deal with aligned organic 1D nanostructures [4] because they are complex to pattern; [5] often requiring templates, an external electric field, or surface-invasive steps. Consequently, simple patterning and aligning methods of 1D crystals are highly desirable in the pursuit of low-cost, large-scale fabrication of parallel device arrays. Here, we report a one-step method that can enable the growth, alignment, and periodic patterning of organic 1D single-crystal nanowires on a solid substrate. This method combines the processes of solvent-evaporation-induced selfassembly, contact line pinning, and dewetting, thus promising to be a simple and versatile approach to prepare sophisticated nanostructures. [6,7] To demonstrate the efficiency of the method we choose a squaraine dye, 2,4-bis[4-(N,N-dimethylamino)phenyl]squaraine (SQ), as model organic semiconductor, because squaraines are a novel class of organic dyes for photonic applications such as imaging, nonlinear optics, photovoltaics, biological labeling, and photodynamic therapy.[8] Both ground and excited states of SQ are intramolecular donor-acceptor-donor charge-transfer (D-A-D CT) states and have been studied theoretically.[9] SQ molecules easily form aggregates in a ''slipped stack'' arrangement because of strong intermolecular interactions between the acceptor (A) and the donor (D) groups (Fig. S1 in the Supporting Information). [10] As it has been shown that strong donor-acceptor dipole-dipole intermolecular interactions can direct the growth of 1D nanostructures, [11] we expect SQ also to have a strong tendency to form 1D nanostructures under appropriate conditions. We report here the preparation of SQ nanostructures by solvent evaporation on a horizontal substrate. In a typical experiment, a drop of SQ/CH 2 Cl 2 solution (0.02 mM, about 10 mL) was placed on a silicon substrate at 20 8C. After complete evaporation of solvent, the substrate was examined by scanning electron microscopy (SEM). As shown in Figure 1a, many nanowires were deposited on the substrate. The majority of the nanowires had a length of about 40 mm and a diameter of 100-300 nm. The dimensions of the nanowires were found to be sensitive to the surface morphology of the substrate, temperature, and evaporation rate. However, under a saturated vapor environment, no nanowires formed on the substrate after solvent evaporation.The morphology of the nanowires was further characterized by transmission electron microscopy (TEM; Fig. 1b), which shows that the SQ nanostructures are solid wires of nanometer diameter. The nanowires are single-crystall...

The photoconductivity of a methyl squarylium (MeSq) single‐nanowire device shows a high light sensitivity, wavelength‐dependent photoresponse, good response speed, and excellent stability and reproducibility. Nanodevices fabricated on flexible substrates (see figure) exhibit good mechanical bendability and no obvious change in performance after bending to a curvature of 0.5 cm−1.

Graphene is considered to be a large aromatic molecule, the limiting case of the family of polycyclic aromatic hydrocarbons. This fascinating two-dimensional material has many potential applications, including fi eld effect transistors (FETs). However, the graphene sheets in these devices have irregular shapes and variable sizes, and contain various impurities and defects, which are undesirable for applications. Moreover, the bandgap of graphene is zero and, consequently, the on / off ratios of graphene FETs are small, making it diffi cult to build logic circuits. To overcome these diffi culties, we report here a bottom-up attempt to fabricate nanoscale graphene FETs. We synthesize structurally well-defi ned coronene molecules (consisting of 13 benzene rings) terminated with linker groups, bridge each molecule to source and drain electrodes through the linkers, measure conductance and demonstrate the FET behaviour of the molecule.