Due to their extraordinary properties, single-crystalline organic nanowires (NWs) are important building blocks for future low-cost and efficient nano-optoelectronic devices. However, it remains a critical challenge to assemble organic NWs rationally in an orientation-, dimensionality- and location-controlled manner. Herein, we demonstrate a feasible method for aligned growth of single-crystalline copper phthalocyanine (CuPc) NW arrays with high density, large-area uniformity and perfect crossed alignment by using Au film as a template. The growth process was investigated in detail. The Au film was found to have a critical function in the aligned growth of NWs, but may only serve as the active site for NW nucleation because of the large surface energy, as well as direct the subsequent aligned growth. The as-prepared NWs were then transferred to construct single NW-based photoconductive devices, which demonstrated excellent photoresponse properties with robust stability and reproducibility; the device showed a high switching ratio of ∼180, a fast response speed of ∼100 ms and could stand continuous operation up to 2 h. Importantly, this strategy can be extended to other organic molecules for their synthesis of NW arrays, revealing great potential for use in the construction of large-scale high-performance functional nano-optoelectronic devices.

Highly uniform single-crystalline Bi19S27(Br3–x,Ix) alloyed nanowires (NWs) (0 ≤ x ≤ 3) were achieved for the first time. The NWs show a composition-independent band gap and have great application potential in optoelectronic devices.

Single-crystalline organic nanowires (NWs) are important building blocks for future low-cost and efficient nano-optoelectronic devices due to their extraordinary properties. However, it remains a critical challenge to achieve large-scale organic NW array assembly and device integration. Herein, we demonstrate a feasible one-step method for large-area patterned growth of cross-aligned single-crystalline organic NW arrays and their in-situ device integration for optical image sensors. The integrated image sensor circuitry contained a 10 × 10 pixel array in an area of 1.3 × 1.3 mm2, showing high spatial resolution, excellent stability and reproducibility. More importantly, 100% of the pixels successfully operated at a high response speed and relatively small pixel-to-pixel variation. The high yield and high spatial resolution of the operational pixels, along with the high integration level of the device, clearly demonstrate the great potential of the one-step organic NW array growth and device construction approach for large-scale optoelectronic device integration.

Single-crystal organic nanostructures show promising applications in flexible and stretchable electronics, while their applications are impeded by the large incompatibility with the well-developed photolithography techniques. Here we report a novel two-step transfer printing (TTP) method for the construction of organic nanowires (NWs) based devices onto arbitrary substrates. Copper phthalocyanine (CuPc) NWs are first transfer-printed from the growth substrate to the desired receiver substrate by contact-printing (CP) method, and then electrode arrays are transfer-printed onto the resulting receiver substrate by etching-assisted transfer printing (ETP) method. By utilizing a thin copper (Cu) layer as sacrificial layer, microelectrodes fabricated on it via photolithography could be readily transferred to diverse conventional or non-conventional substrates that are not easily accessible before with a high transfer yield of near 100%. The ETP method also exhibits an extremely high flexibility; various electrodes such as Au, Ti, and Al etc. can be transferred, and almost all types of organic devices, such as resistors, Schottky diodes, and field-effect transistors (FETs), can be constructed on planar or complex curvilinear substrates. Significantly, these devices can function properly and exhibit closed or even superior performance than the device counterparts fabricated by conventional approach.

A series of red-emitting Ca 2−x Al 2 SiO 7 :xEu 3+ (x = 1 mol.%-10 mol.%) phosphors were synthesized by the sol-gel method. The effects of annealing temperature and doping concentration on the crystal structure and luminescence properties of Ca 2 Al 2 SiO 7 :Eu 3+ phosphors were investigated. X-ray diffraction (XRD) profiles showed that all peaks could be attributed to the tetragonal Ca 2 Al 2 SiO 7 phase when the sample was annealed at 1000°C. Scanning electron microscopy (SEM) micrographs indicate that the phosphors have an irregularly rounded morphology with particles of about 200 nm. Excitation spectra showed that the strong broad band at around 258 nm and weak sharp lines in 350-490 nm were attributed to the charge transfer band of Eu 3+ −O 2− and f-f transitions within the 4f 6 configuration of Eu 3+ ions, respectively. Emission spectra implied that the red luminescence could be attributed to the transitions from the 5 D 0 excited level to the 7 F J (J = 0, 1, 2, 3, 4) levels of Eu 3+ ions with the main electric dipole transition 5 D 0 → 7 F 2 (618 and 620 nm), and Eu 3+ ions prefer to occupy a lower symmetry site in the crystal lattice. Moreover, the photoluminescence (PL) intensity was strongly dependent on both the sintering temperature and doping concentration, and the highest PL intensity was observed at an Eu 3+ concentration x = 7 mol.% after annealing at 1100°C. The obtained Ca 2 Al 2 SiO 7 :Eu 3+ phosphor may have potential application for the red lamp phosphor.