Hybrid Nanostructure Arrays Research Articles

Ultrasensitive surface-enhanced Raman scattering detection of urea by highly ordered Au/Cu hybrid nanostructure arrays.

We report a simple approach to fabricate cost-effective and highly sensitive surface-enhanced Raman scattering substrates based on Au/Cu hybrid nanostructure arrays for the detection of urea, an important molecule in biological and medical fields. By effectively adjusting the gap size between neighbouring nanorods into the sub-10 nm regime, a high density of hot-spots was generated, enabling the substrates to detect urea signals at a concentration as low as 1 mM with great reproducibility.

Ultrafast Dynamics of Metal Plasmons Induced by 2D Semiconductor Excitons in Hybrid Nanostructure Arrays

With the advanced progress achieved in the field of nanotechnology, localized surface plasmon resonances are actively considered to improve the efficiency of metal-based photocatalysis, photodetection, and photovoltaics. Here, we report on the exchange of energy and electric charges in a hybrid composed of a two-dimensional tungsten disulfide (2D-WS2) monolayer and an array of aluminum (Al) nanodisks. Femtosecond pump–probe spectroscopy results indicate that within ∼830 fs after photoexcitation of the 2D-WS2 semiconductor energy transfer from the 2D-WS2 excitons excites the plasmons of the Al array. Then, upon the radiative and/or nonradiative damping of these excited plasmons, energy and/or electron transfer back to the 2D-WS2 semiconductor takes place as indicated by an increase in the reflected probe at the 2D-exciton transition energies at later time delays. This simultaneous exchange of energy and charges between the metal and the 2D-WS2 semiconductor resulted in an extension of the average lifetime ...

Highly Ordered Ag/Cu Hybrid Nanostructure Arrays for Ultrasensitive Surface‐Enhanced Raman Spectroscopy

Despite significant progress recently made in this field, the practical application of surface‐enhanced Raman spectroscopy (SERS) is frequently limited by the lack of highly sensitive, reproducible, and cost‐effective substrates. The fabrication of SERS substrates with a consistently high density of hot‐spots is a key step to address this issue. Here, a simple approach is reported for the fabrication of Ag/Cu hybrid nanostructure arrays as highly sensitive and cost‐effective substrates for SERS application. By effectively tuning the gap size between neighboring nanorods to sub‐10 nm and increasing the packing density of nanorods, ordered Cu nanorod arrays can be used as cheap and effective SERS substrates in their own right. After sputtering a very thin layer of Ag nanoparticles on the surface of the Cu nanorods to get sub‐5 nm gaps, further field enhancement is enabled. A cascaded field enhancement has been evidenced by the electromagnetic simulations. The Ag/Cu hybrid nanostructure arrays exhibit a detection limit down to 10−15 m for nonresonant molecules such as benzenethiol.

STED nanolithography of three-dimensional plasmonic structures

The application of the STED method (STimulated Emission Depletion) to silver photoreduction and metal and metalorganic nanostructure formation is demonstrated. We study the influence of various factors on the process of STED nanolithography. We investigate the morphology and structural parameters of the hybrid nanostructure arrays produced with the STED method. The influence of silver nanoparticles on the physical properties of photoinitiator molecules (DETC) manifests itself in a lifetime reduction of the excited state with 2.3 to 0.6 ns. A new method of additive nanotechnology is proposed.

Synthesis of Au–ZnO hybrid nanostructure arrays and their enhanced photocatalytic activity

The as-prepared Au–ZnO hybrid nanostructure exhibits superior photodegradation ability on methyl orange compared to the ZnO nanorod array without Au particles.

Highly porous Ti/SnO 2 network composite film as stable binder-free anode materials for lithium ion batteries

• A 3D porous Ti/SnO 2 network film was designed and prepared. • The 3D network composites consists of Ti core and SnO 2 shell. • The 3D network film shows promising capacity and enhanced cycling performance. Electrodes with three-dimensional (3D) nanostructure are expected to improve the energy and power densities of lithium ion batteries. Herein, we report a 3D porous Ti/SnO 2 nanocomposite which was prepared by a novel experimental procedure combining the dealloying technique and hydrothermal treatment. Its structure and electrochemical properties were investigated with scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) analysis, X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray (EDX) spectroscopy and galvanostatic charge–discharge tests. The results of electrochemical tests showed that the porous composite anode presented the largest reversible capacity of 616.0 mA h g −1 at the first cycle; and it still delivered a reversible Li storage capacity of 432.5 mA h g −1 after 100 cycles. Our work suggests the possibility of further improving the specific capacity/energy density of 3D microelectrodes by designing ordered hybrid nanostructure arrays.

Doubling the efficiency of third harmonic generation by positioning ITO nanocrystals into the hot-spot of plasmonic gap-antennas.

We incorporate dielectric indium tin oxide nanocrystals into the hot-spot of gold nanogap-antennas and perform third harmonic spectroscopy on these hybrid nanostructure arrays. The combined system shows a 2-fold increase of the radiated third harmonic intensity when compared to bare gold antennas. In order to identify the origin of the enhanced nonlinear response we perform finite element simulations of the nanostructures, which are in excellent agreement with our measurements. We find that the third harmonic signal enhancement is mainly related to changes in the linear optical properties of the plasmonic antenna resonances when the ITO nanocrystals are incorporated. Furthermore, the dominant source of the third harmonic is found to be located in the gold volume of the plasmonic antennas.

Effect of Chromium Interlayer Thickness on Optical Properties of Au‐Ag Nanoparticle Array

The effect of chromium interlayer thickness on optical properties of array of hybrid Au‐Ag triangular nanoparticles is systematically investigated. The optical spectrum simulated by discrete dipole approximation (DDA) numerical method shows that with increase of the chromium interlayer thickness both refractive index sensitivity (RIS) and figure of merit (FOM) of localized surface plasmon resonance from the hybrid nanostructures experience remarkable change and the intensity of the extinction efficiency decreases. The nanosphere lithography (NSL) is used to fabricate the hybrid nanostructure arrays with different chromium interlayer thicknesses. The experiment demonstrates that the spectrum as measured from the as‐fabricated hybrid nanostructure arrays is essentially in agreement with the simulated results.

Highly conductive carbon–CoO hybrid nanostructure arrays with enhanced electrochemical performance for asymmetric supercapacitors

Highly conductive carbon–CoO nanowire array electrodes on 3D nickel foam were designed with ultrahigh specific capacitance (3282.2 F g−1), approaching the CoO theoretical value. Assembled into an asymmetric supercapacitor, the energy density is ∼58.9 W h kg−1, a record among Co-based supercapacitors.

Template synthesis of SnO2/α-Fe2O3 nanotube array for 3D lithium ion battery anode with large areal capacity

Electrodes with three-dimensional (3D) nanostructure are expected to improve the energy and power densities per footprint area of lithium ion microbatteries. Herein, we report a large-scale synthesis of a SnO(2)/α-Fe(2)O(3) composite nanotube array on a stainless steel substrate via a ZnO nanowire array as an in situ sacrificial template without using any strong acid or alkali. Importantly, both SnO(2) and α-Fe(2)O(3) contribute to the lithium storage, and the hybridization of SnO(2) and α-Fe(2)O(3) into an integrated nanotube structure provides them with an elegant synergistic effect when participating in electrochemical reactions. Large areal capacities and good rate capability are demonstrated for such a composite nanotube array. Particularly noteworthy is that the areal capacities (e.g. 1.289 mAh cm(-2) at a current rate of 0.1 mA cm(-2)) are much larger than those of many previous thin-film/3D microbattery electrodes. Our work suggests the possibility of further improving the areal capacity/energy density of 3D microelectrodes by designing ordered hybrid nanostructure arrays.