We present a novel soft-nanoimprint procedure to fabricate high-quality sub-wavelength hole arrays in optically thick films of gold on glass substrates. We fabricate 0.5 × 0.5 mm2 structures composed of a square array of 180 nm-diameter holes with a 780 nm pitch. Optical angular transmission measurements on the arrays show clear extraordinary transmission peaks corresponding to the dispersion of surface plasmon polaritons propagating on either side of the metal film. The transmission features can be strongly controlled by engineering the dielectric environment around the holes. As the nanoimprint procedure enables fabrication of nanoscale patterns over wafer-scale areas at low cost, these imprinted metal nanoparticle arrays can find applications in, e.g., optical components, photovoltaics, integrated optics, and microfluidics.

Photonic crystal nanolasers are fabricated and operated simply, and can be applied as disposable sensors for biomedical applications. They are sensitive to the change with environmental index and surface charge. Functionalizing the nanolaser surface with an antibody, the specific binding of target antigen is detected with a detection limit 2–4 orders lower than that achieved by current standard methods, enzyme-linked immuno-sorbent assay. Nanolasers also detect negatively-charged deoxyribonucleic acid from their emission intensity. This technique requires neither labels nor spectroscopy, which simplifies screening procedures. Its applicability for high-speed detection of endotoxin and for label-fee imaging of living cells are also demonstrated.

Metatronics, or metamaterial-inspired optical nanocircuitry, has provided a powerful toolset to tailor and implement modular quasi-static circuit functionalities in the optical regime. So far, these concepts have been mostly limited to linear operations, while many of the relevant operations in integrated circuits require nonlinear responses. In this work, we introduce nonlinear infrared nanocircuit elements exploiting large quantum conductance driven by photon-assisted tunneling and enhanced by hybrid plasmonic nanojunctions. Based on these concepts, we present infrared lumped nanocircuit mixers and switches for second-harmonic generation, and wide-spectrum self-amplitude modulators based on nanorods.

In this work, photonic crystals of plasmonic/excitonic semiconductor nanocrystals (NCs) were assembled from non-thermal plasma-synthesized boron (B)-doped silicon (Si) NCs. The photonic crystals form an inverse opal structure with larger refractive index than the conventional crystals made from silica nanoparticles and are aimed at controlling light propagation via excitonic and plasmonic absorption of the B-doped Si NC as well as the photonic band gap of the photonic crystal. Furthermore, we demonstrate self-assembly of mesoscopic photonic crystal particles consisting of B-doped Si NCs with well-defined inverse opal structure via simple aerosol processing.

Optoplasmonic networks consisting of dielectric microsphere resonators and plasmonic nanoantennas in a morphologically well-defined on-chip platform support unique electromagnetic signatures that are hybrids of photonic whispering gallery modes and localized surface plasmon resonances. Here we explore the dependence of their near- and far-field responses on the key structural parameters, including the size of the gold nanoparticles forming the plasmonic elements, the separation between the microspheres, and the geometry of the chain. The high degree of structural flexibility, which is experimentally accessible through template guided self-assembly approaches, makes these optoplasmonic structures a unique electromagnetic material for tuning spectral shapes and intensities.

Plasmonic waveguides can transport light while still confining it beyond the diffraction limit. Recently, crossing plasmonic waveguides have been suggested for the implementation of higher-density optical networks. However, suppressing undesirable scattering at their crossing point is still a challenging task because waveguides in these structures are physically connected. Here, we present an experimental demonstration of surface plasmon propagation on an overcrossing metallic waveguide fabricated by a pick-and-place method. By spatially separating the waveguides, the undesirable interaction at the interconnection can be suppressed. Our approach could be a powerful platform to achieve high-density integration of optical waveguides.

Thin films of the conjugated polymer poly(3-hexylthiophene) (P3HT) of different morphological structures were fabricated using both conventional spin-casting and the matrix-assisted pulsed laser evaporation (MAPLE). Films deposited by MAPLE exhibit inhomogeneous morphologies comprised globular subfeatures with dimensions of the order of 100 nm. We show that whereas the in-plane carrier mobilities of MAPLE-deposited films (8.3 × 10−3 cm2/V/s) are comparable with those of spin-cast analogs (5.5 × 10−3 cm2/V/s), the out-of-plane mobilities are an order of magnitude lower (4.1 × 10−4 cm2/V/s versus 2.7 × 10−3 cm2/V/s). Both in- and out-of-plane carrier transport characteristics of MAPLE-deposited films indicate a broad density of states and high carrier trap concentration. Optical absorbance spectroscopy not only corroborates a high degree of energetic disorder in MAPLE-deposited films, but also suggests that the P3HT chains possess average conjugation lengths comparable with spin-cast counterparts. Our findings, rationalized in terms of the Gaussian Disorder Model, describing carrier transport in an environment characterized by both positional and energetic disorder, provide important perspectives on the extent to which disorder impacts mechanisms of charge transport in conjugated polymers.

We demonstrate the gravure printing of a high-performance indacenodithiophene (IDT) copolymer, indacenodithiophene–benzothiadiazole (C16IDT–BT), onto self-aligned organic field-effect transistor architectures on flexible plastic substrates. We observed that the combination of a gravure-printed dielectric with gravure-printed semiconductor yielded devices with higher mean-effective mobility than devices manufactured using photolithographically patterned dielectric. Peak mobilities of μ = 0.1 cm2 V−1 s−1 were measured, and exceed previous reports for non-printed C16IDT-BT on non-flexible silicon substrates.

Metal oxide-based transistors can be fabricated by low-cost, large-area solution processing methods, but involve a trade-off between low processing temperature, facile charge transport and high-capacitance/low-voltage transistor gates. We achieve these simultaneously by fabricating zinc oxide and sodium-incorporated alumina (SA) thin films with temperature not exceeding 200 to 250 °C using aqueous and combustion precursors, respectively. X-ray reflectivity shows a compositionally distinct SA boundary layer forming near the substrate and that a portion of the SA is chemically removed during the subsequent semiconductor deposition. Improved etch resistance and reduced dielectric leakage was obtained when (3-glycidoxypropyl) trimethoxysilane was included in the SA precursor.

In this work, we showcased a visible-light-assisted reduction of graphene oxide (GO) using N-doped TiO2 photocatalysts. Bench scale capacitive deionization (CDI) experiments determine the optimum working voltage for TiO2–reduced graphene oxide (RGO) nanocomposites as CDI electrodes at 1.8 V. Furthermore, the coupled TiO2 nanoparticles within the as-prepared composite also exhibited photocatalytic ability by removing the humic acid model pollutant. This property is expected to be beneficial as it could relieve the degree of fouling on the electrosorptive surface caused by dissolved organic compounds. In the end, we have demonstrated their potential as a viable desalination water treatment technology in a pilot scale CDI unit.

This paper presents experimental results supporting a theory that electric fields accelerate the growth of tin (Sn) whiskers. We have rapidly (within one week) grown long (~100 µm) and dense (~300 mm−2) whiskers on thin Sn films. Humidity and an applied electric field are found to have a strong effect when applied together, making whiskers orders of magnitude longer and denser. An evidence of explosive whisker development is presented.

The remarkable optoelectronic and especially photovoltaic performance of hybrid organic–inorganic perovskite (HOIP) materials drives efforts to connect materials properties to this performance. From nano-indentation experiments on solution-grown single crystals we obtain elastic modulus and nano-hardness values of APbX3 (A = Cs, CH3NH3; X = I, Br). The Young's moduli are ~14, 19.5, and 16 GPa, for CH3NH3PbI3, CH3NH3PbBr3, and CsPbBr3, respectively, lending credence to theoretically calculated values. We discuss the possible relevance of our results to suggested “self-healing”, ion diffusion, and ease of manufacturing. Using our results, together with literature data on elastic moduli, we classified HOIPs amongst the relevant material groups, based on their elastomechanical properties.

Beyond the traditional phase conversion or biphase mixing hybrid, we developed the dilute magnesium-doped wollastonite inks and three-dimensional (3D) printing approaches to fabricate the ultrahigh strength bioceramic porous scaffolds. The mechanical strength (>120 MPa) of the porous bioceramics was an order of magnitude higher than the pure wollastonite and other stoichiometric Ca–Mg silicate porous bioceramics. This abnormal but expected improvement in strength in bioceramic scaffolds is equivalent or even superior to the mechanical requirement in load-bearing bone defects. The breakthrough is totally unexpected, and it quickly opens the door for the 3D printing bioceramics manufacture and large-area segmental bone defect repair applications.

A correction method for linear hardening materials is brought forward to obtain the true (or nearly true) modulus of cylindrical specimens with middle aspect ratios in compression tests. By considering the stress concentration near the interface between the specimen and the compression platen caused by slanted contact, a “sandwich” model is developed. A correction formula is derived and all parameters can be obtained from the tested stress–strain curve. Experiments were performed on Al 2024 specimens with four aspect ratios. The corrected results are closer to the intrinsic modulus than the tested values, which verify the effectiveness of the correction method.